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Calculation Heater-Tube thickness in Petroleum refineres

Calculation Heater-Tube thickness in Petroleum refineres

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API STD 530 Document Transcript

  • 1. ~~ A P I STD*530 96 m 0732290 05bL2918bT m Calculation of Heater-Tube Thickness in Petroleum Refineries API STANDARD 530 FOURTH EDITION, OCTOBER 1996 American Petroleum InstituteCOPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 2. A P I STDx530 9b 0732290 0 5 b l 1 2 9 2 7Tb D Calculation of Heater-Tube Thickness in Petroleum Refineries Manufacturing, Distribution and Marketing API STANDARD 530 FOURTH EDITION, OCTOBER1996 American Petroleum InstituteCOPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 3. A P I STD*530 96 m 0732290 0 5 6 3 2 9 36 3 2 m SPECIAL NOTES API publications necessarily address problems of a general nature. With respect to partic- ular circumstances, local, state, and federal laws and regulations should be reviewed. API is not undertaking to meet the duties of employers, manufacturers, or suppliers to warn and properly train and equip their employees,and others exposed, concerning health and safety risks and precautions, nor undertaking their obligations under local, state, or federal laws. Information concerning safety and health risks and proper precautions with respect to par- ticular materials and conditions should be obtained from the employer, the manufacturer or supplier of that material, or thematerial safety data sheet. Nothing contained in any API publication is to be construed as granting any right, by implication or otherwise, for manufacture, sale, or use of any method, apparatus, or prod- the uct covered by letters patent. Neither should anything contained in the publication be con- strued as insuring anyone against liability for infringement of letters patent. Generally,API standards are reviewed and revised, reaffirmed, or withdrawn at least every five years. Sometimes a one-time extension of up to two years will be added to this review cycle. This publication will no longer be in effect five years after its publication date as an operative AFI standard or, where an extension has been granted, upon republication. Status of the publication can be ascertained from the API Authoring Department [telephone (202) 682-8000]. A catalog of API publications and materials is published annually and updated quarterly by API, 1220 L Street, N.W., Washington, D.C. 20005. This document was produced under API standardization procedures that ensure appropri- ate notification and participation in the developmental process and is designated as an API standard. Questions concerning the interpretation of the content of this standard or com- ments and questions concerning the procedures under which this standard was developed should be directed in writing to the director of the Authoring Department (shown on the title page of this document), American Petroleum Institute, 1220 L Street, N.W., Washington, D.C. 20005. Requests for permission to reproduce or translate all or any part of the material published herein should also be addressed to the director. API standards are published to facilitate the broad availability of proven, sound engineer- ing and operating practices. These standards are not intended to obviate the need for apply- ing sound engineering judgment regarding whenand where these standards should be utilized. The formulation and publication of API standards is not intended in any way to inhibit anyone from using anyother practices. Any manufacturer marking equipment or materials in conformance with the marking requirements of an AFI standard is solely responsible for complying with all the applicable requirements of that standard. API does not represent, warrant, or guaranteethat such prod- ucts do in fact conform to the applicable API standard. All rights reserved. No part o this work may be reproduced, stored in a retrieval system, or f transmitted by any means, electronic, mechanical, photocopying, recording, or otherwise, without prior written permission from publisheE Contact the Publisher; the API Publishing Services, 1220 L Street, N. W , Washington, D.C. 20005. Copyright O 1996 American Petroleum InstituteCOPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 4. A P I STD*530 96 m 0732290 05b1294 579 FOREWORD This standardis based on the accumulated knowledge experience of petroleum refin- and ers, fired-heater manufacturers, and engineering contractors. The objective of this publica- tion is to provide a calculation procedure that will facilitate the design and procurement of fired-heater tubesused in general refinery service and related process facilities. This standard requires the purchaser to specify certain details. Although the purchaser may desire to modify, delete, or amplify sections of this publication, it is strongly recom- mended that all modifications, deletions, and amplifications be made by supplementing this standard rather than by rewriting or incorporating sections of this publication into another standard. API publications may be used by anyone desiring to do so. Every effort has been made by the Institute to assure the accuracy and reliability of the data containedin them; however, the Institute makes no representation. warranty, or guaranteein connection with this publica- tion and hereby expressly disclaims any liability or responsibility forloss or damage result- ing from its use or for the violation of any federal, state, or municipal regulation with which this publicationmay conflict. Suggested revisions are invited and should be submitted to director of the Manufacturing, the Distribution and Marketing Department, American -Petroleum Institute, 1220 L Street, N.W., Washington, D.C. 20005. iiiCOPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 5. API STD+530 96 m 0732290 05bL4L7 887 m IMPORTANT INFORMATION CONCERNING USEOF ASBESTOS OR ALTERNATIVE MATERIALS Asbestos is specified or referenced for certain components of the equipment described in some API standards. It has been of extreme usefulness in minimizing fire hazards associated with petroleum processing. Ithas also been a universal sealing material, compatiblewith most refining fluid services. Certain serious adversehealth effects are associatedwith asbestos, among them the serious and often fatal diseases lung cancer, asbestosis,and mesothelioma (a cancer the chest and of of abdominal linings). The degree of exposure to asbestos varies with the product and the work practices involved. Consult the most recent edition of the Occupational Safety and Health Administration (OSHA), U.S. Department of Labor, Occupational Safety and Health Standard for Asbestos, Tremolite, Anthophyllite, and Actinolite, 29 Code of Federal Regulations Section 1910.1001; the U.S. Environmental Protection Agency, National Emission Standard for Asbestos, Code 40 of Federal Regulations Sections 61.140 through 61.156; and the U.S. Environmental Protec- tion Agency (EPA) rule on labeling requirements and phased banning of asbestos products (Sections 763.160- 179). There are currently in use and under development a number of substitute materials to replace asbestos in certain applications. Manufacturers and users are encouraged to develop and use effectivesubstitutematerialsthat can meetthespecifications for, and operating requirements of,the equipment towhich they would apply. SAFETY AND HEALTH INFORMATION WITH RESPECT TOPARTICULAR PROD- UCTS OR MATERIALS CAN BE OBTAINED FROM THE EMPLOYER, THE MANUFAC- TURER OR SUPPLIER OF THAT PRODUCT OR MATERIAL, OR THE MATERIAL SAFETY DATA SHEET.COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 6. . ~ A P I STDx530 96 m 0732290 0563295 405 m CONTENTS Page SECTION I-GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Scope 1.1 ......................................................... 1 1.2 Information Required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Limitations 1.3 .................................................... 1 1.4 Definitions of Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.5 Referenced Material Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 SECTION%-DESIGN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.2 Equation forStress .............................................. 4 2.3 Elastic Design (Lower Temperatures) ................................ 5 2.4 Rupture Design (Higher Temperatures) .............................. 5 2.5 Intermediate Temperature Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.6 Minimum Allowable Thickness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.7 Minimum and Average Thicknesses ................................. 5 2.8 Equivalent Tube Metal Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.9 Return Bends and Elbows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 SECTION 3-ALLOWABLE STRESSES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 General 3.1 ....................................................... 10 3.2 ElasticAllowableStress .......................................... 10 3.3 RuptureAllowableStress ......................................... 10 3.4 RuptureExponent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 3.5 Yield and Tensile Strengths . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 3.6 Larson-Miller ParameterCurves .................................... 11 3.7 Limiting Design Metal Temperature ................................. 11 3.8 Allowable Curves Stress .......................................... 11 SECTION 4-SAMPLE CALCULATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91 4.1 Elastic Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91 4.2Thermal-StressCheck (for ElasticRange Only) ........................ 91 4.3Rupture Design With Constant Temperature ........................... 93 4.4Rupture Design With LinearlyChangingTemperature . . . . . . . . . . . . . . . . . . . 94 APPENDIX A-DATA SOURCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 APPENDIX B-DERIVATION OF CORROSION FRACTION AND TEMPERATURE FRACTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101 APPENDIX C-CALCULATION OF MAXIMUM RADIANT SECTION TUBESKIN TEMPERATURE,............................ 10.5 APPENDIX D-THERMAL-STRESS LIMITATIONS (ELASTICRANGE) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111 APPENDIX E-ESTIMATION OF REMAINING TUBE LIFE . . . . . . . . . . . . . . . 113 APPENDIX F- CALCULATION SHEETS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117 APPENDIX G-BIBLIOGRAPHY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121 VCOPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 7. A P I STD*530 76 m 0732290 0563276 3 4 3 m Figures I-Corrosion Fraction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 2-Temperature Fraction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 3-Return Bend and Elbow Geometry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 4A-Low-Carbon Steel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 4B-Medium-Carbon Steel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 4C-C./, Mo Steel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 4D-1 1/4Cr-1/zMo Steel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 4E"2I/,C r.1Mo Steel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 4F-3Cr-1Mo Steel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 4G"5Cr-/JVio Steel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 4H"SCr./,M o.Si Steel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 41-7Cr.1/, Mo Steel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 4J-9Cr-IMoSteel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 4K-9Cr-1Mo-VaSteel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 4L-Types 304 and 304H Stainless Steel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 4M"Types 3 16 and 3 16H Stainless Steel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 4N- Type 3 16LStainless Steel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 40-Type 321 Stainless Steel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 4P-Type 321H Stainless Steel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 4Q"Types 347 and 347H Stainless Steel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 4R-Alloy 800H. ASTM B 407 UNS N08810 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 4S-HK-40 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 4A (SI)-Low-Carbon Steel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 4B (SI)-Medium-Carbon Steel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 4C (SI)-C.l/, Mo Steel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 4D (SI)-I /4Cr-1/2Mo Steel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 4E (SI)-2/,C r.1Mo Steel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 4F(SI)-3Cr-lMo Steel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 4G (SI)--SCr.l/, Mo Steel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 4H (SI)-5Cr.1/,M o.Si Steel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 41(SI)-7Cr./, MoSteel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 45 (SI)-9Cr-lMo Steel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71 4K(SI)-9Cr- 1Mo-Va Steel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 4L (SI)-Types 304 and 304HStainless Steel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 4M (SI)-Types 3 16 and 3 16H Stainless Steel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77 4N (SI)-Type 316LStainless Steel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79 4 0 (SI)-Type32 1 Stainless Steel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81 4P (SI)-Type 321HStainless Steel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83 4Q (SI)-Types347and 347H StainlessSteel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 4R (S1)"Alloy 800H, ASTM B 407 UNS N088 1 O . . . . . . . . . . . . . . . . . . . . . . . . . 87 4S(SI)-HK-40 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89 5-Sample Calculation.Elastic Design ................................... 91 &"Sample Calculation. Rupture Design (Constant Temperature) . . . . . . . . . . . . . . 94 7"Sample Calculation, Rupture Design (Changing Temperature) . . . . . . . . . . . . . 96 C-l-Ratio of Maximum Local to Average Heat Flux . . . . . . . . . . . . . . . . . . . . . . . 107 Tables l-Minimum Allowable Thickness of NewTubes . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2-Summary of Working Equations ..................................... 6 viCOPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 8. ~ A P I STD*530 96 0732290 0561297 2 8 8 m 3”Material Constantfor Temperature Fraction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 &Limiting Design Metal Temperature for Heater-Tube Alloys . . . . . . . . . . . . . . . 10 5”Index to Allowable Stress Curves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 A-l-Sources of Data for Yield. Tensile. and Rupture Strengths . . . . . . . . . . . . . . . 97 E-l-Approximate Operating History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113 E-2-Life Fractionsfor Each Period . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114 E-3-Future LifeFractions. Minimum Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . 115 E-4-Future Life Fractions. Average Strength ............................. 115COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 9. Calculation of Heater-Tube Thickness in Petroleum Refineries SECTION 1 4 E N E R A L 1.I Scope c. A temperature-allowance equalto 25°F (15OC). This standard provides procedures and design criteria for d. The corrosion fraction givenin Figure 1. calculating the required wall thickness of new tubes for e. The elastic-range thermal-stress limits. petroleum refinery heaters. These procedures are appropriate for designing tubes that will be used in both corrosive and 1.3 Limitations noncorrosiveservices.Theseprocedures havebeen devel- oped specifically for the design of refinery and related The design procedures described in this standard are sub- process-fired heater tubes (direct-fired, heat-absorbing tubes ject to the limitations of 1.3.1 through 1.3.7. within enclosures). These procedures are not intended to be 1.3.1 Theallowablestressesarebased on a consideration used for the designof external piping. of yield strength and rupture strength only; plastic or creep This standard represents accepted engineering approaches strain has been not considered. Using these allowable based on up-to-date knowledge of the subject. Thebases and stresses may result in small permanent strains in some appli- sources of the procedures, particularly the design equations cations; however, these small strains will not affect the safety and stresses, are describedin Sections 2 and 3. or operability of heater tubes. Appendix A describes in detail the sources of the data used to develop the allowable stresses. Appendix B presents the 1.3.2 No considerations are included for adverse environ- derivations of the equations for corrosion fraction and tem- mental effects such as graphitization, carburization, or perature fraction. Appendix C describes a procedure for cal- hydrogen attack.Limitationsimposed by hydrogen attack culating the skin temperature of a heater tube. Appendix D can be developed from the Nelson curves [Reference 11.l describes limits forthermal stresses in heater tubes. 1.3.3 These design procedures have been developed for This standard does not include recommendations concern- seamless tubes. When they are applied to tubes that have a ing tube retirementthickness, but Appendix E describes a longitudinal weld, the allowable stressvalues should be mul- technique for estimating the life remains in a heater tube. that tiplied by the appropriate joint efficiency factor. Joint effi- ciency factors shall not be applied to circumferential welds. 1.2 Information Required When the use of this standard is specified, the usual design 1.3.4 Thesedesignprocedures have been developed for parameters4esign pressures, design fluid temperature, cor- thin tubes (tubes with a thickness/outside diameter t,,,/D,ratio rosion allowance, and tube material-mustbe defined. In of less than 0.15). Additional considerationsmay apply to the addition, the following information must be furnished: design of thicker tubes. a. The design life of the heater tube. 1.3.5 No considerations included are for the effects of b. Whether the equivalent-temperature concept is to be cyclic pressure or cyclic thermal loading. applied. If so, the operating conditions at the start andthe 1.3.6 Thedesignloadingincludesonly internal pressure. end of the run must be furnished. Limits for thermal stresses areprovided in Appendix D. Lim- c. The temperature allowance, if any. its for stresses developed by weight, supports, end connec- d.Thecorrosionfraction (if different from that shown i n tions, and so forth are not discussed in this standard. Figure 1). e. Whether elastic-range thermal-stresslimits are to be applied. 1.3.7 Mostofthe Larson-Millerparametercurves in 3.8 are not Larson-Miller curves in the traditional sense but are If any of Items a-e are not furnished, the following appli- derived from the 100,000-hour rupture strength as explained cable parameters shouldbe used: in A.3. Consequently, the curves may not provide a reliable a. A design life equal to 100,000 hours. estimate of the rupture strength for a design life that is less b. A design metal temperature based on the maximum metal than 20,000 hours or more than 200,000 hours. temperature. (The equivalent-temperature concept shall not apply.) References in brackets are listed in Appendix G. 1COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 10. API S T D x 5 3 0 76 0732290 0 5 b L 2 9 9 050 2 API STANDARD 530 Figure 1-Corrosion FractionCOPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 11. ~~ A P I STD8530 Yb m 0732290 05b1300bT2 m CALCULATION OF THICKNESS PETROLEUM REFINERIES HEATER-TUBE IN 3 1.4 Definitions ofTerms 1.4.7 The minimum thickness (t,,,), in inches (millimeters), is the minimum required thickness of a new tube, taking into Terms used in this standard are defined in 1.4.1 through account all appropriate allowances. (See Equation 5). 1.4.15. 1.4.8 The stress thickness (tJ, in inches (millimeters), 1.4.1 The design metal temperature (Td),in degrees Fahr- excludes all thickness allowancesand is calculated from enheit (degrees Celsius), is the tube metal, or skin, temperature Equations 2 and 4 that use the allowable stress. used fordesign. It shallbedetermined by calculating the maximum tube metal temperature (T,,,in Appendix C) or the 1.4.9 The outside diameter (Do),in inches (millimeters), is equivalent tube metal temperature (Te in 1.4.2) and adding an the outside diameter of a new tube. appropriate temperature allowance (see 1.4.6). A procedure 1.4.1O The actual inside diameter (Di),in inches (millime- for calculating the maximum tube metal temperature from ters), is the inside diameter of a new tube. The actual inside the heat flux is included in Appendix C. When the equivalent diameter shall be used to calculate the tubeskin temperature in tube metal temperature is used, the maximum operating tem- Appendix C and the thermal stress in Appendix D. perature can be higherthan the design metal temperature. 1.4.1 1 The inside diameter (D’i),in inches (millimeters), is 1.4.2 The equivalent metal tube temperature (TJ, in the inside diameter of a tube with the corrosion allowance degrees Fahrenheit (degreesCelsius), is a calculated constant removed. The inside diameter of a cast tube is the inside metal temperature that in a specified period of time produces diameter of the tube with the porosity and corrosion allow- the same creep damage as does a linearly changing metal ances removed. This inside diameter shall be used inthe temperature (see 2.8). design calculations. 1.4.3 The elastic design pressure (P,), in pounds per 1.4.12 The design rife (&), in hours, is the operating time square inch gauge (megapascals gauge), is maximum the used as a basis for tube design. The design life is not neces- pressure that the heater coil will sustain for short periods of sarily the same asthe retirement or replacement life. time. This pressure is usually related to relief valve settings, 1.4.13 The elastic allowable stress (Se), in pounds per pump shut-in pressures, and so forth. square inch (megapascals), is the allowable stress for the 1.4.4 The rupture design pressure (P,), pounds per square in elastic range (see 3.2). (See 1.3.3 for information about tubes inch gauge (megapascals gauge), is the maximum operating that have longitudinal welds.) pressure that the coil section will sustain during normal opera- 1.4.14 The rupture allowable stress (S?), in pounds per tion. The tube must withstand this pressure during long peri- square inch (megapascals), is the allowable stressfor the ods of operation. If the pressure changes during an operating creep-rupturerange(see 3.3). (See 1.3.3 for information run, the highest operating pressure should be used. about tubes that have longitudinal welds.) Note: The rupture design pressure is usually less than the elastic design pres- sure. The characteristic that differentiates these IWO pressures is the relative 1.4.15 The ruptureexponent (n) is a parameter usedfor length of time over which they are sustained. The rupture design pressure is design in the creep-rupture range. (See A.4). a long-term loading condition that remains relatively uniform over a period of years. The elastic design pressure is usually a short-term loading condi- tion that typically lasts only hours or days. The rupture design pressure is 1.5 ReferencedMaterialSpecifications used in the rupture design equation, since creep damage accumulates as a result of the action of the operating, or long-term, stress. The elastic design The current editions of the following ASTM2 specifica- pressure is used in the elastic design equation to prevent excessive stresses tions are cited in 3.8: in the tube during periodsof operation at the maximum pressure. A 53 Zinc-Coated Welded and Seamless Black 1.4.5 The corrosionallowance(CA ), in inches(millime- and Hot-Dipped Steel Pipe ters), is thepart of thetubethicknessthat is included for A 106 SeamlessCarbonSteelPipe for High- corrosion. Temperature Service A 161 Seamless Low-Carbon and Carbon- 1.4.6 The temperature allowance (TA), in degrees Fahren- Molybdenum Steel Still Tubes for Refin- heit (degrees Celsius), is the part of the design metal temper- ery Service ature that is included for process-or flue-gas maldistribution, A 192lA 192M Seamless Carbon Steel Boiler Tubes for operating unknowns, and design inaccuracies. The tempera- High-pressure Service ture allowance is added to the calculated maximum tube metal temperature or to the equivalent tube metal tempera- *American Society for Testing Materials, 1916 Race Street. Philadel- and ture to obtain the designmetal temperature (see 1.4.1). phia. Pennsylvania 19103.COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 12. A P I STD+530 9b W 0732290 05bL30L 5 3 9 m 4 API STANDARD 530 A200 SeamlessIntermediateAlloy-Steel Still A 3 1ZIA 3 12M Seamless and Welded Austenitic Stainless Tubes for Refinery Service Steel Pipe A 209/A 209M Seamless Carbon-Molybdenum Alloy- A 335/A 335M SeamlessFerritic Alloy Steel Pipe for Steel Boiler and Superheater Tubes High-Temperature Service A210/A 210M SeamlessMedium-CarbonSteelBoiler A 376/A 376M Seamless Austenitic Steel Pipe for High- and Superheater Tubes Temperature Central-Station Service A213/A 213M SeamlessFerriticandAusteniticAlloy Steel Boiler; Superheater and Heat A 608 Centrifusally Cast Iron-Chromium-Nickel Exchange Tubes High-Alloy Tubing for Pressure Applica- A 271 SeamlessAustenitic Chromium-Nickel tion atHigh Temperatures Steel Still Tubes Refinery Service for B407 Nickel-Iron-Chromium Alloy Seamless Pipe and Tube SECTION 2-DESIGN 2.1 General tion that uses these methods is included in Section 4. Calcu- lation sheets (seeAppendix F) are available for summarizing There is a fundamental differencebetween the behavior of the calculations of minimum thickness and equivalent tube carbon steel in a hot-oil heater tube operating at 575°F metal temperature. (300°C) and that of chromium-molybdenum steel in a cata- The minimum allowable thickness of a new tube is given in lytic-reformer heater tube operating at 1 1 10°F (600°C). The Table 1. steel operating at the highertemperature will creep, or All of the design equations described in this section are deform permanently, even at stress levels wellbelowthe summarized in Table 2. yield strength. When the tube metal temperature is high enough for the effects creep to be significant, the tube will of eventually fail from creep rupture,even when a corrosion or 2.2 EquationforStress oxidation mechanism is not active. For the steel operating at In both the elastic range and the creep-rupture range, the the lower temperature, the effects of creep will be nonexis- design equation is based on the mean-diameter equation for tent or negligible. Experience indicates that in this case the stress in a tube. In the elastic range, the elastic design pres- tube will last indefinitely unless a corrosion or oxidation sure (Pe)and the elastic allowable stress (S,) are used. In the mechanism is active. creep-rupture range, the rupture design pressure (P,) and the Since there is a fundamental difference between the behavior rupture allowable stress (S,) are used. of the materials at these two temperatures, there are two differ- The mean-diameter equation gives a good estimate of the ent design considerations for heater tube"-lastic design and pressure thatwill produce yielding through the entire tube creep-rupture design. Elastic designisdesign in theelastic wall in thin tubes (see 1.3.4 for a definition of thin tubes).The range, at lower temperatures, in whichallowablestressesare mean-diameter equationalsoprovidesagoodcorrelation basedontheyieldstrength(see 2.3). Creeprupture design between the creep rupture of a pressurized tube and a uniaxial (which is referred to below as rupture design) is design in the test specimen. It is therefore a good equation to use in both creeprupture range, at higher temperatures, in which allowable the elastic range and the creep-rupture range [References 2, stresses are basedon the rupture strength (see 2.4). 3, 4, 51. The mean diameter equation for stress as follows: is The temperature that separates the elastic and creep rupture ranges of a heater tube is not a single value; it is a range of temperatures that depends on the alloy. For carbon steel, the lower end of this temperature range is about 800°F (425°C); Where: for Type 347 stainless steel,the lower end of this temperature S= stress, in pounds p e r square inch (megapascals). range is about 1100°F (590°C). The considerations that govern P = pressure, in pounds per square inch (megapascals). the design range also include the elastic and rupture design D, = outside diameter, in inches (millimeters). pressures, the design life, and the corrosion allowance. D i = inside diameter, in inches (millimeters). In the temperature range nearor above the point where the t = thickness, in inches (millimeters). elastic and rupture allowable stress curves cross, elastic both and rupture design equations must be used. The larger value The equations for the stress thickness (tJ in 2.3 and 2.4 were of t,,, should govern the design (see 2.5). A sample calcula- derived from Equation 1.COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 13. ~~ A P I STD*530 9b m 0732290 5b3302 75 0 q m CALCULATION OF HEATER-TUBE THICKNESS PETROLEUM REFINERIES IN 5 2 3 Elastic Design (Lower Temperatures) . This design equation is suitable for heater tubes; however, if special circumstances require that the user choose a more The elastic design is based on preventing failure by burst- conservative design, a corrosion fraction unity (f = 1)may of ing when the pressure is at its maximum (that is,when a be specified. pressure excursionhas reached P,) near the end of the design life after the corrosion allowance has been used up. With the elastic design, t, and t,,, (see 2.6) are calculated as follows: 2.5 IntermediateTemperatureRange P, D o P, Di At temperatures near or above the point where the curves = - or f ,= - of S, and S, intersect on the figures in 3.8, either elastic or 2s,+P, 2s,-p, rupture considerationswill govern the design. In this temper- t,,, = t, + CA (3) ature range, both the elastic and rupture designs should be Where: applied. Thelarger value oft, shall govern the design. S, = the elastic allowable stress at the design metal tem- perature, in pounds per square inch (megapascals). 2.6 Minimum AllowableThickness The minimum thickness (r,,,) of a new tube (including the 2.4 Rupture Design (Higher Temperatures) corrosion allowance) shall not be less than that shown in Table The rupture design is based on preventing failure by creep 1. For ferritic steels, the values shown are the minimum thick- rupture during the design life. With the rupture design, t, and nesses of Schedule 40 average wall pipe. For austenitic steels, r,, (see 2.6) are calculated as follows: the values are the minimum thicknesses of Schedule 1 s aver- 0 age wallpipe.(Table 5 shows which alloys are ferritic and P, D o P D, which are austenitic.) The minimum thicknesses are 0.875 t , = - or I, = - 2s,tP, 2S,-P, times the average thicknesses. These minimums are based on industry practice. The minimum thickness is not the retirement or replacement thickness of a used tube. Where: S, = rupture allowable stress at the design metal temper- 2.7 Minimumand AverageThicknesses ature and the design life, in pounds per square inch The minimum thickness (t,,,) is calculated as described in (megapascals). 2.3 and 2.4. Tubes that are purchased to this minimum thick- f = corrosion fraction given as a function of B and n in ness will havean average thickness that is greater. thickness tol- A Figure 1. erance is specified in each ASTM specification.For most of the B = CAIt,. ASTM specifications shown on the figures in 3.8, the toler- n = ruptureexponent at the design metal temperature ance on the minimum thickness is - , +28 percent for hot-fin- O (shown on the figures i n 3.8). ished tubes and - , +22 percent for cold-drawn tubes. This is O equivalent to tolerances onthe average thickness of r12.3 Thederivation of the corrosion fraction is described in percent and r9.9 percent, respectively. The remaining ASTM Appendix B. It is recognized in this derivation that stress is specifications require that the minimum thickness be greater reduced by thecorrosionallowance;correspondingly, the than 0.875 times the average thickness, which is equivalent rupture life is increased. to a tolerance on the average thickness of k12.5 percent. Table 1-Minimum Allowable Thicknessof New Tubes Minimum ThicknessSteel Ferritic Diameter Outside Tube Millimeters Inches Inches Millimeters 2.375 60.3 O. 135 3.4 0.095 2.4 2.875 73.0 0.178 4.5 0.105 2.7 0.189 3.50 88.9 4.8 O. 105 2.7 4.00 101.6 0.198 5.0 0.105 2.7 4.50 114.3 0.207 5.32.7 O. 105 5.563 5.7 0.117 3.0 6.625 0.245 6.2 0.117 3.0 0.282 8.625 219.1 3.3 7.2 0.130 10.75 3.7 8.1 0.144 COPYRIGHT American Petroleum Institute Licensed by Information Handling Services
  • 14. A P I STDx530 96 W 0 7 3 2 2 9 0 0563303 301 W 6 API STANDARD 530 Table 2-Summary of Working Equations Elastic design (lower temperatures): t , = t, + CA Rupture design (higher temperatures): 1, = t, t fCA Where: t, = stress thickness, in inches (millimeters). P = . elastic design pressure, in pounds per square inch gauge [megapascals(gauge)]. P, = rupture design pressure, in pounds per square inch gauge [megapascals (gauge)]. D, = outside diameter, in inches (millimeters). D: = inside diameter with corrosion allowance removed, in inches (millimeters). S, = elastic allowable stress at the design metal temperature, in pounds per square inch (megapascals). S, = in pounds per square inch (megapascals) rupture allowable stress at the design metal temperature and design life, t, = minimum thickness, including corrosion allowance, in inches (millimeters). CA = corrosion allowance, in inches (millimeters). f = corrosion fraction, given in Figure 1 as a function of E and n. B = CA - tS n = ruptureexponent at thedesignmetaltemperature. Equivalent tube metal temperature: Where: T, = equivalent tube metal temperature, in degrees Fahrenheit (degrees Celsius). T,, = tube metal temperature at start of run, i n degrees Fahrenheit (degrees Celsius). T,,, = tube metal temperature at end of run, in degrees Fahrenheit (degrees Celsius). fT = temperature fraction, given i n Figure 2 as a function of VandN. N = no = rupture exponent at T,,. AT Tm, - T , , , temperature change during operating period,in degrees Fahrenheit (degrees Celsius). = T, T,,+ 460, in degrees Rankine (T,,, + 273, in kelvin). = A material constant, from Table 3, in pounds per square inch (megapascals). = S, = initial stress at start of run using Equation 1, in pounds per square inch (megapascals). At = RL,, thickness change during operating period, in inches (millimeters). R = corrosion rate, in inches per year (millimeters per year). L, = duration of operating period, i n years. to = initial thickness at start of run, i n inches (millimeters).COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 15. A P I STD*530 96 m 0732290 0563304 248 m CALCULATIONHEATER-TUBE OF THICKNESS PETROLEUM IN REFINERIES 7 With a - , +28-percent tolerance, a tube that is purchased O 2.8 Equivalent Tube Metal Temperature to a 0.500-inch (12.7-millimeter) minimum-thickness speci- In the creep-rupture range, the accumulation of damage is a fication will have the following averagethickness: function of the actual operating temperature. For applications (0.500)(1 + 0.28/2) = 0.570 inch (14.5 millimeters) in which there is a significant difference between start-of-run To obtain a minimum thickness of 0.500 inch (12.7 milli- and end-of-run metal temperatures, a design based onthe meters) in a tube purchased to a -.12.5-percent tolerance on maximum temperature may be excessive, since the actual the average thickness, the average thickness must be speci- operating temperature will usually be less than the maximum. fied as follows: For a linear change in metal temperature from start of run to end of run (Teor), equivalent tube metal tempera- an (0.500)(1/0.875) = 0.571 inch (14.5 millimeters) can ture (TL) be calculated as shown below. A tube operating All thickness specifications shall indicate whether the at the equivalent tube metal temperature will sustain the specified value is a minimum or an average thickness. The same creep damageas one that operates from the start-of-run tolerance used to relate the minimum and average wall thick- to end-of-run temperatures. nesses shall be the tolerance given in the ASTM specification to which the tubes will be purchased. T, = T o r + f~(Teor - T o r ) V = no [y][e]In no = rupture exponent at T,,, . AT = Te",- T,,,, temperature change during operating period, in degrees Fahrenheit (degrees Celsius). T, = T , , + 460, in degrees Rankine (To,273, in degrees kelvins). + In = natural logarithm. Ac = m,,,thickness change during operating period,in inches (millimeters). R = corrosion rate, in inches per year (millimeters per year). L, = duration of operating period, in years. r, = initial thickness at start of run, in inches (millimeters). S,, = initial stress at start of run using Equation 1, in pounds p e r square inch (megapascals). A = material constant, in poundsper square inch (megapascals). See Table 3. Figure 2"Temperature FractionCOPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 16. A P I STD*530 96 m 0732270 0563305 184 m 8 API STANDARD 530 L, = duration of operating period, in years. to = initial thickness at start of run in inches (millimeters). The constant A is given in Table 3. The significance of the Outer Radius material constant is explained in B.5. The temperature fraction and the equivalent temperature shall be calculated for the first operating cycle. In applications that involve very high corrosion rates, the temperature fraction for the last cycle will be greater than that for the first. In such cases, the calculation of the temperature fraction and the equivalent temperature should be based on the lastcycle. If the temperature change from start of run to end of run is other than linear, a judgment shall be made regarding the use of the value of f T given in Figure 2. Note that the calculated thickness of a tube is a function of the equivalent tempera- ture, which in turn is a function of the thickness (through the Figure 3-Return Bend and initial stress). A few iterations may therefore be necessary to Elbow Geometry arrive at the design (see the sample calculation in 4.4). Where: and Bends Return 2.9 Elbows T, = equivalent tube metal temperature, in degrees Fahr- The design procedure in this section shall be applied to enheit (degrees Celsius). austenitic stainlesssteel return bends and elbows (see Figure T,, = tube metal temperature at start of run, in degrees 3) located in the firebox and operating in the elastic range. In Fahrenheit (degrees Celsius). this situation, the allowable stress does not vary much with T,,, = tube metal temperature at end of run, in degrees temperature. This design procedure shall also be applied in Fahrenheit (degrees Celsius). other situations, if applicable. f T = temperature fraction given in Figure 2. The stressvariations in a return bend or elbow arefar more complex than in a straight tube. Thehoopstresses at the Thederivation of thetemperaturefraction is described in inner radius (or crotch) of a return bend are higher than in a Appendix B. The temperature fraction is a function oftwo straight tube of the same thickness. In the situation defined parameters, V and N above, the minimum thickness at the crotch may need to be greater than the minimum thickness of the attached tube. Due to the reduced exposure to radiant gases, the metal Table 3-Material Constant for Temperature Fraction ConstantA Where: Pounds Per Material TypeInch or Grade Square Megapascals no = rupture exponent at T,, . AT = T,,, - T,,, temperaturechange during operating Low-carbon steel 1.08 x lo* 7.46 x los Medium-carbon steel B 4.17 X 107 2.88 x 105 period, in degrees Fahrenheit (degrees Celsius). C-I/,Mo steel T1 or Pl 2.91 x 109 2.01 x 107 T, = T,,, + 460, in degrees Rankine (T,,, t 273, in degrees l-l/,Cr-l/,Mo steel 2-/,Cr-lMo steel T11 orPl1 T22 or P22 7.49 x 1.25 x 109 lo* 5.17 x 8.64 x 107 los kelvins). 3Cr-1Mo steel T21 or P21 3.07 x 108 2.12 x 106 In = natural logarithm. 5Cr-/,Mo steel T5 or P5 7.97 X 107 5.49 x 105 5Cr-L/,Mo-Si steel T5b or P5b 4.18 x 10 2.88 x 10 A = material constant, in pounds per square inch (mega- 7Cr-/, Mo steel T7 or P7 2.37 x IO7 1.64 x 10s pascals). 9Cr-1 Mosteel T9 or P9 1.09 x 109 7.54 x 106 9Cr-IMO steel Va T91 or P91 3.24 x 108 2.23 x 106 So = initialstress at start of run using Equation 1, in 18Cr-8Ni steel 304 or 304H 2.25 x 108 1.55 x 106 pounds per square inch (megapascals). 16Cr-12Ni-2Mosteel 316 or 316H 1.79 x 108 1.24 x 106 16Cr-12Cr-2Mo steel 316L 1.99 x 108 1.37 x 106 At = M,, thickness change during operating period, in 18Cr-1ONi-Ti steel 321 1.92 x 108 1.32 x 106 inches (millimeters). 18Cr-1ONi-Ti steel 321 H 4.00 x lo7 2.76 x 1W 18Cr-ION¡-Cb steel 347 or 347H 1.79 x 1n O 1.23 x 106 R = corrosion rate, in inches peryear (millimeters per Ni-Fe-Cr Alloy 800H 1.50 x lo7 1.03 x 10 year). 2.50-20Ni HK-~O 3.63 x lo7 2.50 x 1WCOPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 17. CALCULATION OF HEATER-TUBE THICKNESS PETROLEUM REFINERIES IN 9 temperature at the inner radius of a return bend in thefirebox Sr = elastic allowablestress at the design metal tempera- is lower than that of the fully exposed surface of the straight ture, in pounds per square inch (megapascals). tube. For this reason and because modern fabrication pro- The design metal temperature shall be the estimated temper- cesses for forged return bends result in greater thickness at ature at the inner radiusplus an appropriate temperature the inner radius, the higher stresses the inner radius can be at allowance. sustained without failurein most situations. Using the approximation given above, Equation 8 can be The hoop stress along the inner radius of the bend given by is solved for the stress thickness at the outer radius. elastic For 2R - r m stress design thickness the follows: is as S, = S (7) 2(R- Tm) D,e Where: f, s = 2N0 S, + e (11) si= stress, in pounds per square inch (megapascals). Where: R = center line radius of the bend, in inches (millime- ters). r,,thickness = stress radius, at outer in inches (millime- r,,, = mean radius of the tube, in inches (millimeters). ters). S = stress given by Equation 1, in pounds per square R 4-+2 inch (megapascals). & = - Do A n (12) The hoop stress alongthe outer radius is given by 4"+l DO S, = elastic allowable stress at the designmetal tempera- Where: ture, in pounds p e r square inch (megapascals). So = stress, in pounds per square inch (megapascals). The design metal temperature shall be the estimated temper- ature at theouterradius plus an appropriate temperature Using theapproximation that r,,, is almost equal to D,/2, allowance. Equation 7 can be solved for the stress thickness at the inner The minumum thickness at the inside radius, tsi, and out- is radius. For elastic design the stress thickness as follows: side radius, t,,, shall be calculated using Equations 9 and 11. The corrosion allowance, CA, shall be added to the mini- mum calculated thickness. The minimum thickness along the neutral axisof the bend Where: shall be the same as for a straight tube. tsi = stress thickness at inner radius, in inches (millime- Thisdesignprocedure is for return bends and elbows ters). located in the firebox that may operate at temperatures close to that of the tubes. This procedure may not be applicable to R 4 - -2 these fittings if they are located in header boxes since they D O N i= - will operate at lower temperatures.Otherconsiderations, R (10) 4 - -1 such as hydrostatic test pressure, may govern the design of D O fittings located in header boxes.COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 18. A P I STDJ530 96 m 0732290 0563307 T57 m 10 API STANDARD 530 SECTION >ALLOWABLE STRESSES 3.1 General son-Miller parameter curves for the minimum rupture strength shown on the right-hand side of Figures 4A-4S. For The allowable stresses for various heater-tube alloys are a design life other than those shown, the corresponding rup- plotted against design metal temperature in Figures 4 A 4 S . ture allowable stressshall be developed from the Larson- The values shown in the figures are recommended only for Miller parameter curves for the minimum rupture strength the design of heater tubes. These figures show two different (see 3.6). allowable stresses, the elastic allowable stress the rupture and If a different design basis is desired, the user shall specify allowable stress. The bases for these allowable stresses are the basis, and the alternative rupture allowable stress shall be given in 3.2 and 3.3 (see also 1.3.3). developed from the Larson-Miller parameter curves for the minimum or average rupture strength.If the resulting rupture 3.2 Elastic AllowableStress allowable stressis greater than the minimum rupture strength Theelasticallowablestress (S,) is two-thirds the yield for the design life, the effects of creep on the tube design strength at temperature for ferritic steels and 90 percent of equation shall be considered. the yield strength at temperature for austenitic steels. The data sources for the yield strength aregiven in Appendix A. 3.4 Rupture Exponent If a different designbasis is desired for special circumstances, the user shall specify the basis, and the alternativeelastic allow- Figures 4 A 4 S show the rupture exponent ( n ) as a func- able stress shall be developed from the yieldstrength. tion of the design metal temperature. The ruptureexponent is used for design in the creep-rupturerange(see2.4).The meaning of the rupture exponentis discussed in A.4. 3.3 Rupture AllowableStress The rupture allowable stressS )is 100 percent of the min- (, 3.5 Yield and Tensile Strengths imum rupture strength for a specified design life. Appendix A defines the minimumrupturestrength and provides the Figures 4 A 4 S also show the yield and tensile strengths. data sources. The 20,000-, 40,000-, 60,000-, and 100,000- These curves are included only for reference. Their sources hour rupture allowable stresses were developed from the Lar- are given in Appendix A. Table 4-Limiting for Design Metal Temperature Heater-TubeAlloys Limiting Design Lower Critical Metal Temperature Temperature Degrees Degrees Degrees Degrees Materials v p e or Grade Fahrenheit Celsius Fahrenheit Celsius Carbon steel B 1O00 540 1325 720 CJ/,Mo steel TI or P1 1100 595 1325 720 1 1/4Cr-1/2Mo steel TllorP11 1100 595 1430 775 2 1/4Cr-1Mo steel T22 or P22 1200 650 1480 805 3Cr-1Mo steel Tz1 or P21 1200 650 1500 815 SCr-’/,Mo steel T5 or P5 1200 650 1510 820 SCr-’/,Mo-Si steel T5b or P5b 1300 705 1550 845 7Cr-’/,Mo steel T7 or P7 I300 705 1515 825 9Cr-1Mo steel T9 or P9 I300 705 1515 825 9Cr-1Mo-Va steel T 9 1 or P91 1200” 650 1525 830 18Cr-8Ni steel 304 or 304H 1500 815 - - 16Cr-12Ni-2Mo steel 316 or 316H 1500 815 16Cr-12Ni-2Mo steel 316L 1500 815 18Cr-10Ni-K steel 321 or 321H 1500 815 18Cr-1ONiCb steel 347 or 3478 1500 815 Ni-Fe-Cr Alloy 800H 1800” 985 25CR-20Ni HK-40 1850’ 1010 “his is the upper limit on the reliability of the rupture strength data (see Appendix A); however, these materials are commonly used for heater tubes at higher temperatures in applications where the internal pressure is so low that rupture strength doesnot govern the design.COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 19. A P I S T D x 5 3 0 9b m 0732290 0563308 993 CALCUUTION OF HEATER-TUBE THICKNESS PETROLEUM REFINERIES IN 11 3.6 Larson-Miller Parameter Curves considered when furnaceare tubes designed. On the right-hand side of Figures 4 A 4 S are plots of the minimum and average 100,000-hour rupture strengths 3.8 AllowableStress Curves against Larson-Miller the parameter. The Larson-Miller Figures 4A-4S provide the elastic allowable stressand the parameter is calculated from the design metal temperature rupture allowable stress formost common heater-tubealloys. (Td)and the design life ( L d ) as follows: When Td is expressed The sources for these curves are provided in Appendix A. in degrees Fahrenheit, The figure number for each alloy is shown in Table 5 . (T, + 460) (C + log,, Ld) x 10 -3 When Td is expressed in degrees Celsius, (Td + 273) (C + log,, Ld) x 10 -3 The Larson-Miller constant C is stated on the curves. (See Table 5-Index to Allowable Stress Curves A.3 for a detailed description of these curves). The plot of the minimum rupture strength against the Lar- Figure Number Alloy son-Miller parameter is included so that the rupture allowable stress can be determined for any design life. The curves shall Ferritic Steels not be used todetermine rupture allowable stresses for temper- 4A Low-carbon steel (A 161, A 192) atures higher than the limiting design metal temperatures 4B Medium-carbon steel (A 53B, A 106B) shown in Table 4 and Figures 4 A 4 S . In addition, the curves 4c CJI2 Mo 4D" 1 1/4Cr-1/2Mo may give inaccurate rupture allowable stresses for times less 4Ea 2 l/,Cr-lMo than 20,000 hours or greater than 200,000 hours (see A.3). 4F" 4G" The curves for minimum and average rupture strength can be 4H used to calculate remaining tube life, as shown Appendix E. in 41" 7Cr-Il;Mo 45" 9Cr-1Mo 4K 9Cr- 1Mo-Va 3.7 Limiting Design MetalTemperature Austenitic Steels The limitingdesign metal temperature for each heater- tube alloy is given in Table 4. The limiting design metal tem- 4L 18Cr-8Niand 304H) (304 4M 16Cr-12Ni-ZMo (316 and 316H) perature is the upper limit of the reliability ofthe rupture 4N 16Cr-12Ni-2Mo (316L) strength Higher data. temperatures-up to 50°F (30°C) 40 180-ION¡-Ti (321) 4P 18Cr-1ONi-Ti (321H) below the lower critical temperature-may be permitted for 4Q 180-1ONi-Cb (347 and 3478) short-term operating conditions, suchas those that exist dur- 4R Ni-Fe-Cr (Alloy 800H) 250-20Ni 4s (HK-40) ing steam-air decoking or regeneration. Operation at higher temperatures may result in changes in the alloys microstruc- "Broken lines on these figures indicate the elastic allowable stresses for the ture. Lower critical temperatures for ferritic steels are shown A 200 grades. These figures do not show the yieldstrengths of the A 200 in Table 4 Austenitic steels do not have lower critical tem- . grades. The yield strengths of the A 200 grades are 83percent of the yield peratures. Other considerations that may require lower oper- strengths shown. The tensile strengths, rupture allowable stresses, rupture strengths, and rupture exponents for the A 200 grades are the same as for ating-temperaturelimitssuchasoxidation,graphitization, the A 213 and A 335 grades. carburization, and hydrogenattack.These factors shall beCOPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 20. A P I S T D x 5 3 0 96 W 0732290 0563307 82T m 12 API STANDARD 530 Future Stress Curves (Customary Units) New stress curves may be added to this standard sometime in the future. As new stress curves are added, revision packages will be prepared and distributed.COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 21. CALCUUTION OF HEATER-TUBE THICKNESS l X O L € U M REFI IN k 300 400 500 600 700 800 900 1O00 Design metal temperature,Td(degrees Fahrenheit) Figure 4A-Low-Carbon Steel, ASTM A 161,COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 22. CALCULATION OF THICKNESS HEATERTUBE IN PETROLEUM REFINERIES 13 (Td+ 460)(20+ log L,) Figure 4A -:nheit) Figure 4A-Low-Carbon Steel, ASTM A 161, A 192COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 23. ~~ A P I STDx530 9b m 0732290 0 5 6 3 3 3 2 314 m CALCULATION OF HEATER-TUBETHICKNESSPETRoLEUM REFI IN ? ! m æ P Design metal temperature, Td(degrees Fahrenheit) Figure 4B-Medium-Carbon Steel, ASTM A 53 Grade B (Seamless), A 11COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 24. A P I STD*530 96 m 0732290 05bL3L3 250 m CALCUlATlON OF THICKNESS HEATER-TUBE INPETROLEUM REFINERIES 15 Figure 4 8COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 25. CALCUlATlON OF THICKNESS HEATER-TUBE INPETROLEUM REFW 300 400 500 600 700 800 900 1O00 1100 Figure 4C-C-/z-Mo Steel, ASTM A 161 T l , A209 TCOPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 26. CALCUUTION OF HEATER-TUBE THICKNESSPETROLEUM REFINERIES IN 17 (Td+ 460)(20 + log L)Ire 4C-C-I2-Mo Steel, ASTM A 161 T l , A209 T l , A335 P1COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 27. ~ ~~ ~ ~~ A P I S T D * 5 3 0 96 0732290 05bL3Lb TbT CALCULATION OF HEATER-TUBETHICKNESSPETFOLEUM REFI? INCOPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 28. Figure 4DCOPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 29. CALCULATION OF THICKNESS PETROLEUM REFI. HEATER-TUBE IN ~ î e .- Design metal temperature,Td (degrees Fahrenheit) Figure 4E-2’/4Cr-l Mo Steel, ASTM A 213 T22, A 335 PCOPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 30. CALCUUTION HEATER-TUBE OF THICKNESSPETROLEUM IN REFINERIES 21 (Td + 460)(20+ log L,,) Figure 4ECOPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 31. CALCUlATlON THICKNESSPETROLEUM REFlt OF HEATER-TUBE IN ~ Design metal temperature,Td (degrees Fahrenheit) Figure 4F"Cr-lMo Steel, ASTM A 213 T21, A 335 FCOPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 32. CALCUIATION HEATER-TUBE OF THICKNESS PETROLEUM IN REFINERIES 23 (Td+ 460)(20 + log L,) 1O-3 Figure 4F !rees Fahrenheit) e 4F-3Cr-1Mo Steel, ASTM A 213 T21, A 335 P21, A 200 T21COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 33. CALCULATION OF THICKNESSPETRoLEUM REFI HEATER-TUBE IN Design metal temperature,T,, (degrees Fahrenheitì Figure 4G”5Cr-”hMo Steel, ASTM A 213 T5, A 335COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 34. CALCULATION OF THICKNESS HEATER-TUBE INPETROLEUM REFINERIES 25 (rd 460)(20 + log L,) + Figure 4G-rees Fahrenheiti-e 4G-!Xr-’/2Mo Steel, ASTM A 213 T5, A 335 P5, A 200 T5COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 35. THICKNESS PETFOLEUM CALCUUTION HEATER-TUBE OF IN REFCOPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 36. CALCULATIONHEATER-TUBE OF THICKNESSPETROEUM IN REFINERIES 27 (T, + 460)(20 + log L,) IO+ 4H"5Cr-/zMo Si Steel, ASTM A 213 T5b, A 335 P5bCOPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 37. CALCUMTION OF THICKNESSPETROLEUM REFIÍ HEATER-TUBE IN P h v) R .- Y m u) E ¿ñ 300 400 500 600800 700 900 1O00 1100 12c Design metal temperature, (degrees Fahrenheit) Td Figure 41"7Cr-/zMo Steel, ASTM A 213 T7, A 335COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 38. CALCULATION OF HEATER-TUBE THICKNESS PETROLEUM IN REFINERIES 29 900 1O00 1100 1200 1300 Figure 41:degrees Fahrenheit)Ure 41"7Cr-hMo Steel, ASTM A 213 T7, A 335 P7, A 200 T7COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 39. CALCULATION OF HEATER-TUBE THICKNESS REFI; IN PETROLEUM Figure 4J-9Cr-1 Mo Steel, ASTM A 213 T9, A 335 FCOPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 40. CALCULATION HEATER-TUBE OF IN REFINERIES THICKNESS PETROLEUM 31 (rd+ 460)(20 + log L,) 10-3 32 34 36 38 40 42 44 90 80 ASTM A 213 T9 70 60 50 40 30 20 10 9 8 7 6 5 4 3 2 1 0.9 0.8 1300re 4J-9Cr-1Mo Steel, ASTM A 213 T9, A 335 P9.A 200 T9COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 41. A P I STD*530 9 6 m 0732290 0561330 33T W THICKNESS PETROLEUM RE; CALCULATION OF HEATER-TUBE IN Design metal temperature, Td(degrees Fahrenheit) Figure 4K-9Cr-1 Mo-Va Steel, ASTM A 213 T91. A 335 P!COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 42. CALCULATION OF HEATER-TUBE THICKNESSPETROLEUM IN REFINERIES 33 (G+ 460)(30 + log L,)lO-J " Figure 4K -9Cr-1 Mo-Va Steel, ASTM A 213 T91, A 335 P91, A 200 T91COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 43. Design metal temperature,T,, (degrees Fahrenheit) Figure 4L"Types 304 and 304H Stainless Steel, ASTM A 213,COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 44. CALCUL4TlON OF HEATER-TUBE THICKNESS PETROLEUM REFINERIES IN 35 (Td + 460)(15 -k log L,) 2a 30 32 34 36 38 40 90 TYPES 304 AND 304H ao : ASTM A 213 Types 304 and304H 70 A 271 Types304 and 304H A 312 Types 304 and 304H A 376 Types 304 and 304H 60 Above 1000°Fthese stress 50 values apply only if carbon content is 0.04 percent e! a 3 U 4 2 lo00 1100 1200 1300 1400 1500 Figure 4LTd(degrees Fahrenheit)pes 304 and 304H Stainless Steel, ASTM A 213,A 271,A 312,A 376COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 45. THICKNESSPETFOLEUM CALCUUTION HEATER-TUBE OF IN REFIF 3 Figure 4M"Types 316 and 316H Stainless Steel, ASTM A 213,COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 46. CALCULATIONHEATER-TUBE THICKNESS OF IN REFINERIES PETROLEUM 37 (Td + 460)(15 + log L) 28 30 32 34 RR 30 I 1O00 1100 1200 1300 1400 1500 Figure 4MS Fahrenheit)pes 316 and 316H Stainless Steel, ASTM A 213,A 271,A 312,A 376COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 47. A P I S T D * 5 3 0 96 m 0732290 0 5 6 3 3 3 6 858 m CALCULATION OF HEATER-TUBE THICKNESS REF IN PETROLEUM temperature, metal Design Td (degrees Fahrenheit) " Figure 4N"Type 31 6L Stainless SteelCOPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 48. CALCULATION OF HEATER-TUBE THICKNESS PETROLEUM REFINERIES IN 39 (Ta+ 460)(15+ log L)103 Figure 4N-Type 31 6L Stainless SteelCOPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 49. CALCULATION OF HEATERTUBE THICKNESS IN PETROLEUM REF b p. 400 500 600 700 800 900 1O00 1100 1200 130 Design metal temperature, T., (degrees Fahrenheit) Figure 40-Type 321 Stainless Steel, ASTM A 21 3, A 271,COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 50. PETROLEUM THICKNESS CALCUlATlON OF HEATER-TUBE IN REFINERIES 41 (Td+ 460)(15 + log L,) 1500-Type 321 Stainless Steel, ASTM A 213, A 271, A 312, A 376COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 51. A P I STD*530 76 9 0732270 563340 87 0 2 9 CALCULATION OF HEATER-TUBE THICKNESS PETFOLEUM IN REF 400 500 600 700 800 900 1O00 1100 1200 130C Design metal temperature, rd(degrees Fahrenheit) Figure 4P"Type 321H Stainless Steel, ASTM A 213, A 2,COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 52. PETROLEUM THICKNESS CALCULATION OF HEATER-TUBE IN REFINERIES 43 (T, + 460)(15+ log L,) lo-’ 28 30 32 34 36 RR 70 60 50 40 30 20 10 9 8 7 6 5 4 3 2 1 1O00 1100 1500 1200 1400 1300 Figure 4P(degrees Fahrenheit)’“Type 321H Stainless Steel, ASTM A 213, A 271, A 312, A 376COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 53. CALCUUTION HEATER-TUBE THICKNESS OF IN PETROLEUM RECOPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 54. ype 347 and 347H Stainless Steel, ASTM A 213, A 271,A 312, A 376COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 55. CALCULATION OF HEATER-TUBE THICKNESS REFI IN PETROLEUM P V C I 1200 1300 1400 1500 1600 1700 1800 1900 Design metal temperature, Td (degrees Fahrenheit) Figure 4R"Alloy 800H, ASTM B 407 UNS NCCOPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 56. CALCULATIONHEATER-TUBE OF IN REFINERIES THICKNESS PETROLEUM 47 (T, + 460)(15 + log Ld)1O- P o c .-, (degrees Fahrenheit) Figure 4R Figure 4R"Alloy 800H,ASTM B 407 UNS N08810COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 57. CALCUlATlON OF HEATER-TUBE THICKNESSPETRoLEUM REFI IN - Design metal temperature, Td(degrees Fahrenheit) Figure 4s -HK-40, ASTM A 608 Grade HKCOPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 58. CALCULATIONHEATER-TUBE OF IN REFINERIES THICKNESSPETROLEUM 49 (T, + 460)(15 + log L d ) 1O” Figure 4s (degrees Fahrenheit) Figure 4s -HK-40, ASTM A 608 Grade HK-40COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 59. CALCUUTION OF HEATER-TUBE THICKNESS PETROLEUM REFINERIES IN 51 Future Stress Curves (SI Units) New stress curves may be added to this standardsometimeinthefuture. As new stress curves are added, revision packages will be prepared and distributed.COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 60. Cesign metal temperature,T,, (degrees Celsius) Figure 4A (SI)-Low-Carbon Steel, ASTM A 161.COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 61. CALCULATION OF HEATEA-TUBE REFINERIES THICKNESS PETROLEUM IN 53iperature, Td(degrees Celsius) Figure 4A (SI)Figure 4A (SI)-Low-Carbon Steel, ASTM A 161, A 192COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 62. CALCULATION OF THICKNESS PETROLEUM RE; HEATER-TUBE IN ~ Design metal temperature,T,, (degrees Celsius) Figure 4B (SI)--Medium-Carbon Steel, ASTM A 53 Grade B (Seamless), ;COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 63. CALCULATION OF HEATER-TUBETHICKNESS INPETROLEUM REFINERIES 55 (T, + 273)(20+ log h) -:mperature. T,, (degrees Celsius) Figure 4 8 (SI) -Carbon Steel, ASTM A 53 Grade B (Seamless), A 106 Grade B, A 210 Grade A-1COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 64. CALCULATION OF THICKNESS HEATER-TUBE IN PETROLEUM REFI DI-sign metal temperature, Td (degrees Celsius) Figure 4C (SI)-C-l/z-Mo Steel, ASTM A 161 T l , A209 TCOPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 65. Figure 4C (SI)emperature, 7. (degrees Celsius)IC (SI)-C-’I2-Mo Steel, ASTM A 161 T l , A209 T l , A335 P lCOPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 66. CALCULATION OF THICKNESS HEATER-TUBE IN PETROLEUM REFI Figure 4D (SI)-1 1/4Cr-1/2Mo Steel, ASTM A 213 T l 1, A 3:COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 67. CALCUUTION HEATER-TUBE THICKNESS OF IN REFINERIES PETROLEUM 59 (T, + 273)(20+ log L,)mperature. Td (degrees Celsius) Figure 4D (SI) ( I - 1/4Cr-1/2M~ S)1 Steel, ASTM A 213 T 1 , A 335 Pl 1, A 200 T l 1 lCOPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 68. CALCUMTION OF HEATER-TUBE THICKNESS PETROLEUM IN REF Figure 4E (SI)-2/4Cr-l Mo Steel, ASTM A 213 T22, A 335COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 69. CALCULATION OF HEATER-TUBE THICKNESS PETROLEUM IN REFINERIES 61 (Td+ 273)(20 + log Ld)1O-3 Figure 4E (St)COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 70. CALCULATION OF HEATER-TUBE REF THICKNESS PETROLEUM INCOPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 71. emperature, Td (degrees Celsius) Figure 4F (SI)F (SI)-3Cr-l Mo Steel, ASTM A 213 T21,A 335 P21, A 200 T21COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 72. CALCULATION OF THICKNESS PETROLEUM REFI HEATER-TUBE IN Design metal temperature, (degrees Celsius) Td Figure 4G (Sl)”5Cr-i/2Mo Steel, ASTM A 213 T5, A 335COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 73. Figure 4G (SI)mperature, T, (degrees Celsius)4G (SI)-5Cr-’/aMo Steel, ASTM A 213 T5, A 335 P5,A 200 T5COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 74. CALCUMTION HEATER-TUBE OF REFI THICKNESS PETROLEUM IN Design metal temperature, Td(degrees Celsius) Figure 4H ( S I ) - ~ C T - ~ / ~ M OSteel, ASTM A 213 T5b, SiCOPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 75. CALCULATION HEATER-TUBE THICKNESS OF IN PETROLEUM REFINERIES 67 (Td+ 273)(20+ log L,) lo-re 4H (SI)-5Cr-1/2Mo Si Steel, ASTM A 213 T5b, A 335 P5bCOPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 76. CALCUlATlON OF THICKNESSPETROLEUM REFIF HEATER-TUBE IN Figure 41 (SI)-7Cr-’hMo Steel, ASTM A 213 T7, A 335COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 77. CALCULATION OF HEATER-TUBE REFINERIES THICKNESSPETROLEUM IN 69 (Td + 273)(20 + log L,,)COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 78. CALCULATION OF THICKNESSPETROLEUM REF HEATER-TUBE IN Design metal temperature, T,, (degrees Celsius) Figure 4J (SI)-9Cr-l Mo Steel, ASTM A 21 3 T9, A 332COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 79. CALCUUTION OF HEATER-TUBE INPETROLEUM REFINERIES THICKNESS 71 (Td+ 273)(20+ log L d ) lo-’: 4J (SI)-9Cr-1 Mo Steel, ASTM A 213 T9, A 335 P9, A 200 T9COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 80. A P I S T D x 5 3 0 96 m 0732290 0563369 2 T 4 CALCULATION OF HEATER-TUBE THICKNESSPETROLEUM REFIN: IN 200 - h m v) 8 m 4 100 90 2. 80 S ! iij 70 60 50 40 30 20 10 200 250 300 500 450 350 400 550 600 650 Design metal temperature, To (degrees Celsius) Figure 4K (SI)"sCr-l Mo-Va Steel, ASTM A 213 T91, A CCOPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 81. CALCULATION HEATER-TUBE THICKNESSPETROLEUM REFINERIES IN 73 + (T,+273)(30 logLd)103 200 60 50 40 30 20 10 500 550 600 650 Figure 4K (SI). (SI)"sCr-l Mo-Va Steel, ASTM A 213 T91, A 335 P91, A 200 T91COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 82. CALCUlATlON OF HEATERTUBE THICKNESSPETROLEUM RE; IN Design metal temperature,Td (degrees Celsius) Figure 4L (SI)-Types 304 and 304H Stainless Steel, ASTM A 2COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 83. CALCUUTION OF THICKNESS PETROLEUM REFINERIES HEATER-TUBE IN 75 (Td + 273)(15 + log 4) -Types 304 ard 304H Stainless Steel, ASTM A 213, A 271, A 312, A 376COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 84. CALCULATION OF HEATER-TUBE REFI. THICKNESSPETROLEUM IN Design metal temperature,To (degrees Celsius) Figure 4M (SI)-Types 316 and 316H Stainless Steel, ASTM A 2COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 85. _ _ _ ~ A P I STDr530 96 m 0732290 05bL37YbbL m CALCULATION OF THICKNESS PETROLEUM REFINERIES HEATER-TUBE IN 77 (Td+ 273)(15+ log L,,) Types 316 and 316H Stainless Steel, ASTM A 213, A 271, A 312, A 376COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 86. CALCULATION OF THICKNESSPETROLEUM REF HEATER-TUBE IN Design metal temperature, Td (degrees Celsius) Figure 4N (SI)-Type 316L Stainless SteelCOPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 87. COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 88. CALCUUTION THICKNESSPETROLEUM REF OF HEATER-TUBE IN ~~ " : temperature, metal Design T,, Celsius) (degrees Zxis? -~ -1- - k 75i Figure 4 0 (SI)-Type 321 Stainless Steel, ASTM A 213,ACOPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 89. CALCUUTION OF HEATER-TUBE IN PETROLEUM REFINERIES THICKNESS 81 (T., + 273)(15 + log L)COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 90. CALCULATIONHEATER-TUBE THICKNESS OF RE; IN PETROLEUM Design metal temperature,Td(degrees Celsius) Figure 4P (St)-Type 321H Stainless Steel, ASTM A 213, A 27COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 91. A P I STD*530 96 H 0732290 0563380 965 H CALCUlnTlON OF HEATER-TUBE THICKNESS PETROLEUM REFINERIES IN 83 (rd 273)(15 + log L ~ 10-3 + ) 14 16 1 22 TYPE 321 H ASTM A 213 Type 321H A 271 Type 321 H A 312 Type 321H A 376 Type 321H 800)-Type 321H Stainless Steel, ASTM A 213,A 271,A 312,A 376COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 92. CALCULATION OF HEATER-TUBE THICKNESS PETRoLEUM REF IN Design metal temperature, Td(degrees Celsius) Figure 4Q (SI)-Type 347 and 347H Stainless Steel, ASTM A 21COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 93. CALCULATION OF HEATERTUBE THICKNESS PETROLEUM REFINERIES IN a5 TYPES 3 4 7 AND 347H ASTM A 21 3 Types and 34714 347 A 271 Types 347 and 347H A 312 Types 347 and 347H A 376 Types 347 and 3471-1 Above 1000°F these stress if values apply only carbon 500 content is 0.04 percent or hipher.COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 94. ~ A P I STD*530 9b 0732290 05bl1383 674 CALCULATIONHEATER-TUBE OF REFI THICKNESSPETROLEUM IN Elastic allowable stress greater thanO0 MPa 1 Design metal temperature, T, (degrees Celsius) Figure 4R (SI)-Alloy 800H, ASTM B 407 UNSCOPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 95. CALCUUTION HEATER-TUBE OF THICKNESS PETROLEUM IN REFINERIES 87 ( T d + 273)(15 + log Ld) Figure 4R (SI)emperature, Td(degrees Celsius) Figure 4R (SI)-Alloy 800H, ASTM B 407 UNS N08810COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 96. CALCULATIONHEATER-TUBE OF THICKNESSPETROLEUM RE IN Elastic allowable stress greater than MPa 100 Design metal temperature, To (degrees Celsius) Figure 4s (SI)-HK-40, ASTM A 608 Grade HKCOPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 97. OF THICKNESS PETROLEUM REFINERIES CALCULATION HEATER-TUBE IN 89 (Td + 273)(15 + log L)lo-’ Figure 45 (SI)-HK-40, ASTM A 608 Grade HK-40COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 98. ~~ A P I STD*530 9 6 m 0732290 05bL387 2LT CALCULATION OF THICKNESS HEATER-TUBE PETROLEUM IN REFINERIES 91 SECTION "AMPLE CALCULATIONS 4.1 Elastic Design Using Equations 2 and 3, Followingisan example that illustrates how the design equations are used for the elastic range. Suppose the following information is given (the SI conversions in parenthesesare approximate): f,,, = 0.159 + 0.125 = 0.284 inch In SI units, Material = 18Cr-1ONi-Cb.Type 347 stainless steel. D, = 6.625 inches (168.3 millimeters). P,. = 900 pounds per square inch gauge (6.2 mega- pascals gauge). Td = 800°F (425°C). r,, = 4.0 + 3.2 = 7.2 millimeters CA = 0.125 inch (3.2 millimeters). This design calculation is summarized on the calculation sheet in Figure 5 . ~ From Figure 4Q or Figure 4Q (SI). S, = 18,250 pounds p e r square inch (125 megapas- 4.2 Thermal-Stress Check (for Elastic cals). Range Only) S, = 20,200 pounds p e r square inch(140megapas-Thethermalstresses in the tube designedaccordingto 4.1 shall Cals). equations be given checked theusing in Appendix D as follows: API STD 530 CALCULATION SHEET Customary Units Heater Plant Spec. ASTM Coil 347 Type Material A 213 Rupture Elastic CALCULATION OF MINIMUM THICKNESS Design Design Outside diameter, inches O, = 6.625 o, = Design pressure, pounds per square inch gauge P, = 900 P, = Maximum or equivalent metal temperature, degrees Fahrenheit T, = T, = Temperature allowance, degrees Fahrenheit TA = TA = Design metal temperature, degrees Fahrenheit T, = 800 Td = Design life, hours - L = Allowable stress at T,, Figures 4A-4S, pounds per squareinch S, = 18,250 S, = Stress thickness, Equation 2 or 4, inches t,. = 0.159 t,= Corrosion allowance, inches CA = 0.125 CA = Figure 1, n = Corrosion fraction, B= - f = Minimum thickness, Equation 3 or 5, inches t, = 0.284 t, = Figure !+Sample Calculation, Elastic DesignCOPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 99. A P I STDa530 96 m 0732290 0 5 b L 3 8 8 L56 m 92 API STANDARD 530 a = 10.05 x 1 P "F" (1.81 x le5 "C-) (thermal expan- The limits for this stress for austenitic steels are given by sion coefficientfrom Table C-3, ASME B31.3). Equations D-4and D-6, in which the yield strength is 20,200 E = 24.1 x lo6pounds per square inch (1.66 x lo5mega- pounds p e r square inch (140 megapascals). pascals) (modulus of elasticity from Table C-6, ASME = [2.7 - 0~9(~~108)](20~200) B31.3 ). v = 0.3 (value commonly used for steels). = 34,400 pounds per square inch 4 = 0 20,000 Btdhr-ft2 (63.1 kW/mz) (assumed heat flux). k= 11.9 Btu/hr-ft-"F (20.6-W/m-"C) (thermal conductiv- = (W(20,~O) ity from Table TCD in the ASME Boiler and Pres- = 36,360 pounds per square inch sure Vessel Code, Section II Part D). In S1 units, Using Equation D-2, S,,./tml = [2.7 - 0.9( 1.108)](140) = 238 megapascals = 8.026 x lo4pounds per square inch S,h.lim2 = (1.8)(140) = 252 megapascals In SI units, Since the maximum thermal stress is less than these limits, X =[ (1.81)(0.3) (63.1)( 168.3) 1 4( 1 - I[ 1.66) (20.6) the design is acceptable. If a thicker tube is specified arbitrarily (as Schedule 80s = 553.2 megapascals might be in this example), the actual average tube thickness shall be used in calculating the thermal stress and its limits as The thickness calculatedin 4.1 is the minimum. The aver- follows: age thickness shall be used in the thermal-stress calculation. The inside diameter of a 6-inch Schedule 80s tube is as The average thickness (see2.7) is calculated as follows: follows: (0.284)(1 t 0.14) = 0.324 inch D, 5.761 inches = In SI units, so, (7.2)(1 t 0.14) = 8.2 millimeters Y = 6.625/5.761 = 1.150 The actual inside diameter is calculated as follows: In SI units, Di = 6.625 - 2(0.324) = 5.977 inches Di 146.3 millimeters = Y = 6.625/5.977 = 1.108 Y = 168.31146.3 = 1.150 In SI units, The term in brackets in Equation D-1 is calculated as Di 168.3 - 2(8.2) = 151.9 millimeters = follows: Y = 168.3/151.9 = 1.108 The term in brackets in Equation D-1 is calculated as fol- 2(1.150)2 In (1.150) - 1 = 0.146 lows: (1.150) - 1 Using Equation D-1, the maximum thermal stress is calcu- 2(1.108)2 In (1.108) - 1 = 0.106 ( 1.10q2 - 1 lated as follows: Using Equation D-1, the maximum thermal stress is calcu- S,h= (8.026 X 104)(0.146) lated as follows: = 11,793 pounds per square inch S = (8.026 X lo4)(0.106) , In SI units, = 8508 pounds per square inch S,, = (553.2)(0.146) In SI units, = 80.9 megapascals S = (553.2) (0.106) , The average thickness of this tube is 0.432 inch (11.0 mil- = 58.6 megapascals limeters), so the minimum thickness is calculated follows:COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 100. ~~ A P I STD*530 96 D 0732290 0561389 O92 CALCUUTION OF THICKNESS PETROLEUM HEATER-TUBE IN REFINERIES 93 From Figure 4Q or Figure 4Q (SI), t, = -= 1 + 0.14 0.379 inch S = 5450 pounds per square inch (37.3 megapascals) , In SI units, Using Equation 4, 11.0 t, = -= 9.6millimeters 1 + 0.14 Using Equation D-7,the stress is calculated as follows: In SI units, = 9001 ) -dm- = 7416 pounds per square inch From this, B = - - o.125 - 0.264 In SI units, 0.474 S = ,, - (E1) = 51.2 megapascals ";" - In SI units, 3.2 B = - = 0.264 The thermal-stress limit based on the primary plus second- 12.1 ary stress intensity is calculated using Equation D-9. Using the values above, this limitis calculated as follows: From Figure 4Q or Figure 4Q (SI), n = 4.4 Srh{iml = 2.7(20,200)-(1.15)(7416) Using these values for B and n, use Figure 1 to obtain the fol- = 46,010 pounds p e r square inch lowing corrosion fraction: In SI units, f = 0.558 Sfhflml = 2.7( 140)-( 1.15)(51.2) Hence, using Equation 5, = 319.1 megapascals t , = 0.474 + (0.558)(0.125) The thermal-stress ratchet limit is calculated using Equa- = 0.544 inch tion D-12. In this case. the limit is as follows: In SI units, Sthgim2 = 4[(1.35)(20,000)-7416] r, = 12.1 + (0.558)(3.2) = 79,416 pounds per square inch = 13.9 millimeters In SI units, To confirm that this is an appropriatedesign, the elastic S,h.[im2 4[(1.35)(140)-51.21 = design shall be checked using theelasticdesign pressure instead of the rupture design pressure. Using Equations 2and = 551.2 megapascals 3 with the conditions given above, The thermal stress in the thicker tube is well below these limits. S, = 16,400 pounds per square inch 4.3 Rupture Design With Constant Temperature A modification of the example in 4.1 illustrates howthe t, = 0.177 + 0.125 = 0.302 inch design equations are used for the creep-rupture range. Sup- pose the tube described in 4.1 is to be designed for the fol- In SI units, lowing conditions: S, = I13 megapascals Td = 1300°F (705°C). L d = 100,000 hours. P, = 840 pounds p e r square inch gauge (5.8 megapascals €wJge)* t, = 4.5 t 3.2 = 7.7 millimetersCOPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 101. 94 API STANDARD 530 Since r,, based on rupture design is greater, it governs the At the start-of-run temperature, no = 4.8.From Table 3,A design. This design calculation summarized on the calcula- is is 1.79 x lo8 pounds per square inch (1.23 x lo6 megapas- tion sheet in Figure 6. cals). The parameters for the temperature fraction are there- fore as follows: 4.4 Rupture Design WithLinearly (-) In ( 1.79 x 10.) V= 4.8 1O0 = 2.9 Changing Temperature 1635 841 3 Suppose the tube describedin 4.3 will operate in a service N = 4.8 (-) 0.013 = 0.2 for which the estimated tube metal temperature varies from 0.315 1175°F (635°C) at the start of run to 1275°F (690°C) at the In SI units, end of run. Assume that the run lasts ayear, during which the thickness will change about 0.013inch (0.33millimeter). Assume that the initial minimum thickness is 0.315 inch (8.0millimeters); therefore, using Equation 1, the initial stress will be as follows: From Figure 2, f T = 0.62, and the equivalent temperatureis 840 1 = 8413 pounds p e r square inch s"=T(m-) calculated using Equation 6 as follows: T, = 1175 t (0.62)(100) = 1237°F In SI units, In S1 units, s o = - f (S - 1) = 58.1 megapascals T, = 635 + (0.62)(55) = 669°C API STD 530 CALCULATION SHEET Customary Units Heater Plant Refineryial Coil ASTM Spec. A 213 Elastic Rupture CALCULATION OF MINIMUM THICKNESS Design Design Outside diameter, inches D, = 6.625 D, = 6.625 Design pressure, poundsper square inch gauge P, = 900 P, = 840 Maximum or equivalent metal temperature, degrees Fahrenheit T,, = T, = Temperature allowance, degrees Fahrenheit TA = TA = Design metal temperature, degrees Fahrenheit T , = 1300 Td = 1300 Design life, hours - L d = 100,000 Figures 4 A 4 S , pounds per square inch Allowable stress at Td, S = 16,400 , S, = 5450 Stress thickness, Equation2 or 4, inches t, = 0.177 f = 0.474 Corrosion allowance, inches CA = 0.125 CA = 0.125 Corrosionfraction, Figure 1, n = 4.4 B = 0.264 - f = 0.558 Minimum thickness, Equation 3 or 5,inches t,, = 0.302 t, = 0.544 ~~ Figure &Sample Calculation, Rupture Design (Constant Temperature) COPYRIGHT American Petroleum Institute Licensed by Information Handling Services
  • 102. CALCUUTION OF HEATER-TUBE PETROLEUM THICKNESSIN REFINERIES 95 A temperature allowance of 25°F (1SOC) is added to yield a With this stress, the temperature-fraction parameters Vand N design temperature of 1262"F, which is rounded up to become the following: 1265°F (685OC). Using this temperature to carry out the design procedure illustrated in 4.3 yields the following: t, = 0.388 inch t, = 0.388 + (0.572)(0.125) = 0.460 inch N = 4.8 (-) 0.013 0.460 = 0.1 In S1 units, In SI units, r, = 9.9 millimeters r,,, = 9.9 + (0.572)(3.2) = 11.7millimeters 38.8 V=4.8 (-) ln ( 908 x lo) = 3.0 This thickness is different from the 0.315-inch (8.0-millime- ter) thickness that was initially assumed. Usingthis thick- N = 4.8 (-) 0.33 11.7 = 0.1 ness. the stressis calculated as follows: Using these values in Figure 2, f T = 0.62, the value that So = 2 (0.460- 6.625 1) = 5629 pounds per square inch was determined in the first calculation. Sincethe temperature fraction didnot change,furtheriteration isnotnecessary. In SI units, Thisdesigncalculation is summarized on the calculation So = 11.72 (6. 1) = 38.8 megapascals 183 - sheet in Figure 7.COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 103. 96 API STANDARD 530 ~ ~ _ _ _ CALCULATION SHEET Customary Units Heater PlantMaterial Coil Spec. 347 ASTM A213 Elastic Rupture CALCULATION OF MINIMUM THICKNESS Design Design Outside diameter, inches D, = D, = 6.625 Design pressure, pounds per square inch gauge P, = P, = 840 Maximum or equivalent metal temperature, degrees Fahrenheit 1 = , T, = 1237 Temperature allowance, degrees Fahrenheit TA = TA = 25 Design metal temperature, degrees Fahrenheit Td = Td = 1265 Design life, hours - Ld = 100,000 Allowable stress at T,, Figures 4A-4S, pounds per square inch S, = S, = 6750 Stress thickness, Equation 2 or 4, inches t j = ts = 0.388 Corrosion allowance, inches CA = CA = 0.125 Corrosionfraction, Figure 1, n = 4.5 B = 0.322 - f = 0.572 Minimum thickness, Equation3 or 5,inches t, = t, = 0.460 CALCULATION OF EQUIVALENT TUBE METAL TEMPERATURE Duration of operating period, years L, = 1.0 Metal temperature, start ofrun, degrees Fahrenheit T,,, = 1175 Metal temperature, end of run, degrees Fahrenheit T,, = 1275 Temperature change during operating period, degrees Fahrenheit AT = l o 0 Metal temperature, start ot run, degrees Rankine T, = 1635 Thickness change during operating period, inches A t = 0.013 Assumed initial thickness, inches 4 = 0.315 Corresponding initial stress, Equation 1 , pounds per square inch S, = 8413 Material constant, Table 3, pounds per square inch A = 1.79 X lo* Rupture exponent at T,,, Figures 4A-4s n ~ 4 . 8 o Temperature fraction Figure 2, V = 2.9 N = 0.2 f, =0.62 Equivalent metal temperature, Equation 6, degrees Fahrenheit T, = 1237 Figure 7-Sample Calculation, Rupture Design (Changing Temperature)COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 104. APPENDIX A-DATA SOURCES A.l General Whenever possible, the yield-, tensile- and rupture-strength (T, t 460)(C t log,, L,) x lC3 data displayed in Figures 4 A 4 S were taken from the ASTM Data Series Publications [References 8, 9, 10, 11, 12, 131 (see When T, is expressed in degrees Celsius, Table A-I). These publications contain discussions and (Td t 237)(C t log,"Ld) x ik3 detailed descriptions of the data that are not repeated in this appendix. The material that follows is limited to a discussion The generally accepted empirical values of C = 20 and C = of deviations from published data and of data that have been 15 are used for ferritic steels and austenitic steels, respec- used but are not generally available. tively. The value of C = 30 is used for T91 or P91,9Cr-lMo- Va steel. To calculate the rupture allowable stress forany given design metal temperature and designlife, the appropri- A.2 MinimumRuptureStrength ate value of C should be used to calculate the parameter, and one ofthe Larson-Miller parameter curves should then be The ASTM Data Series Publications contain evaluations of used to find the corresponding rupture strength. variousrupture-strengthextrapolationtechniques.Fromthese To the right in Figures 4A-4S are Larson-Miller parame- evaluations,themostreliableextrapolationwasselected. The ter curves that permit tubes to be designed for lives other averageand minimum 100,000-hour rupturestrengths,calcu- than 100,000 hours. These curves were developed from the lated by this method are used this standard. The minimumu p in r average minimum and 100,000-hourrupturestrengths. ture strength used is the lower 95-percent confidence limit; 95 They can be usedto estimate the rupture allowable stress percent of all samples should have rupture strengths greater than (minimumrupturestrength)fordesignlivesfrom 20,000 this value. This minimum rupture strength is obtained by .using hours to 200,000 hours. The resulting 20,000-, 40,000-, and least-squares techniques to calculatea curve for the averageu rp 60,000-hour rupture allowable stresses are shown with the ture strength andsubtracting 1.65 times the standard deviationof 100,000-hour rupture allowable stress to the left in Figures the data from this average. The specific figure number and Data 4A-4s. Series reference for each alloy are listed Table A-l. in This is not the normal use of the Larson-Miller parameter. The Larson-Miller curveis traditionally developedfrom rup- A.3Larson-MillerParameterCurves ture-strength test data as one way to extrapolate long-term rupture strengths from short-term data. The resulting extrap- The Larson-Miller parameter combines design metal tem- olation is suitable for some alloys but not for all. Most of the perature, Td, and design life, L,, in hours, as follows: When ASTM Data Series Publications listed in Table A-1 examine Td is expressed in degrees Fahrenheit, the suitability of this Larson-Miller extrapolation. Table A-1-Sources of Data foryield, Tensile, and Rupture Strengths Yield ASTM Tensile Rupture Method n Alloy Strength Strength Strength Strength Used Comments Carbon steels DS l l S l Figure 7c Figure 7d [See AS. 1) LM Fine-grained, tempered values used C-l/,Mo steel DS 47 Figure 7a Figure 7b [See A.5.2) LM 1 1/4Cr-1/zMo steel DS 50 Figure 6c Figure 6d (See A.5.3) IL Nonplate values used. 2 /,Cr-lMo steel DS 6S2 Figure 7a Figure 7b [See A.5.4) MC 3Cr- Mo steel 1 DS 58 Figure 7a Figure 7b Figure 17c IL SCr-/,Mo steel DS 58 Figure 8a Figure 8b Figure 26c IL 5Cr-li2Mo-Si steel DS 58 Figure 9a Figure 9b Figure 33c IL 7Cr-*/,Mo steel DS 58 Figure l l a Figure l l b Figure 47c IL 9CI-1Mo steel DS S8 Figure 12a Figure 12b Figure 54c IL 9Cr-lMo-Va steel MPP LM 18Cr-8Ni steel DS SS2 Figure 14b Figure 15b Tables 7 and 10 IL Adjusted values used. Figures 14a and 15a used above 1000°F l6Cr-12Ni-2Mo steel DS 5S2 Figure 14e Figure 15e Tables 10 7 and IL Adjusted values used. 16Cr-12Ni-2Mo(316L) steel DS 5S2 Table Figure Figure 14f 15f 7 IL Minimum is 80% of average. 18Cr-1ONi-Ti steel DS SS2 Figure 14g Figure 15g Tables 7 and 10 IL Adjusted values used. 18Cr-1ONi-Cbsteel DS 5S2 15h Figure 14h Figure Tables 7 and I O IL Adjusted values used. Ni-Fe-Cr (Alloy 800H) (See A S S ) LM 25CR-20Ni (HK-40) A.5.6)[See LM "See references 8, 9, 10, 11, 12, and 13 in Appendix G for ASTM Data Series publications. bLM = Larson-Miller, IL = Individual lots (see ASTM DS publication for definition), MC = Manson compromise. Data from Materials Properties Council, Inc. 97COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 105. A P I S T D + 5 3 0 96 m 0732270 056337V 4 5 T m API STANDARD 530 The Larson-Miller parameter curves used in this standard AS Modification of and Additions to were developed from the extrapolated values of the 100,000- Published Data hour rupture strength. The values used are those listed in the various ASTM Data Series Publications. They have been esti- Whenever possible, the data used to generate Figures 4A- mated in the manner believed to be most reliable. For low- and 4 s were taken from the ASTM Data SeriesPublications medium-carbon steels, Alloy 800H, and HK 40, the 100,000- [References 8, 9, 10, 11, 12, 131. Specific figure and table hour rupturestrength has been estimated using a Larson- references for the yield, tensile, and rupturestrengthsare Miller extrapolation: other means have been used for the other given in Table A-l. In some cases, rupture-strength the alloys. Table A-1 lists the extrapolation method used for each extrapolations were modified for this practice,or the data alloy. Consequently, the Larson-Miller parameter curves in were used to develop new extrapolations. These modifica- this standard are not the same as those shown in the various tions and additionsaredescribed in A.5.1 through A.5.4. ASTM Data Series Publications. For those cases in which the Alloy 800H and HK-40 are not covered by recent ASTM 100,000-hour rupture strength was determined by other publications. The data used to develop the figures for these means, the Larson-Miller parameter curves in this standard alloys are described in A S S and A.5.6. maynot give reliable estimates ofthe rupture strength for times less than 20,000 hours or more than 200,000 hours. A.5.1 CARBON STEELS A.4 Rupture Exponent The determination of rupture strength in Data Series l l S l makes no distinction between low-carbon steel (A 192) and Constant-temperaturecreep-rupture data can be conve- medium-carbon steel (A 106 and A 210). Data from all three niently plotted on alog-loggraph,log(stress) versus log alloys were used to calculate the Larson-Miller curvein Data (rupture time). These stress-rupture curves can often be rep- Series 11S1. For this standard, the distinction was made for resented by astraightline or can be approximated by a Figures 4A and 4B by separating the data and calculating straightline in limitedregions.Thestraightline can be two Larson-Miller curves. The procedure for establishing the expressed as follows: average and minimum rupture strengths was otherwise iden- L, = mS" tical to that used in Data Series 11S1. Larson-Miller curves that represent the average strengthweregenerated bythe Where: least-squares method; curves that represent minimum L, = rupture time. strength were generated by subtracting from the average- strength curves 1.65 times the standard deviationof the data. m and n = material parameters that are functions of tem- perature. S = stress. A.5.2 C-/2 MO STEEL The parameter n is the rupture exponent; it is related to the The Larson-Miller curves in Figure 18a of Data Series 47 slope of the stress-rupture curve. have an inflection point close to a parameter value of 37. The The value of the rupture exponent can be calculated from upturn to the right is considered questionable. For this stan- two points on the curve. If the rupture time for a stress S, is dard, the parameter curves shown in Figure 4C were arbi- L , and the rupture time for a stress is L,, then S, trarily extended by straight lines above a parameter value of 37. These extensions are shown as dashed lines in Figure 4C. n = log(L,lL*) ~og(S,/S,) A.5.3 1/4 Cr-l/2 Mo STEEL If the stress-rupture curve is a straight line, any two points on The regression of the individual lot extrapolations in Fig- that line will give the same value ofn. If the stress-rupturecurve ure 27c of Data Series 50 used a polynomial of third degree is not a straight line, the value of n will depend on which two or higher. The resulting average and minimum rupture- points arechosen, since the slope of the straight-lineapproxima- strength curves show an upturn to the right. This upturn also tion depends on which part the curve is approximated. of results when the data points shown on Figure 27c are fitted The rupture exponents plotted in Figures 4 A l l s were deter- with a quadratic curve. Since this upturn is considered ques- mined from the 60,000-hourand 100,000-hourminimum rupture tionable, the data points shown in Figure 27c were used to strengthsasestimated bytheLarson-Millerparametercurves. calculate a first-degree curve for this standard. The resulting These particular times were chosen to a straight-line approxi- give curves for average and minimum rupture strengths are shown of mation over the range the usual operating stress levels. in Figure 4D.COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 106. ~~ ~~ STD+530 9b W 0732290 API 0563395 39b m CALCULATION OF THICKNESS PETROLEUM REFINERIES HEATER-TUBE IN 99 A.5.4 2’/4 Cr-1Mo STEEL A.5.6 250-20Ni (HK-40) The most reasonable extrapolation in Data Series 6S2 is pro- The Larson-Miller curves for HK-40 in Figure 4 s were vided bythe strength-temperature regressioncurveshown in developed from 87 rupture-test data points. These tests came Figure 22 and again in Figure 26. As with 11/4Cr-1/2Mo in steel from four sources and involved seven heats of HK-40. The Data Series 50, the regression useda polynomial of third degree carbon content of these heats ranged from 0.35 to 0.45. No or higher. The resulting curve is considered questionable. For datafrom tests that were run at temperatures of 1900°F this standard the Manson compromise curve in Figure 26 was (1038°C) or higher were used in this evaluation, since signif- usedbelow 1100°F (593°C)andwasextendeddownward to icant metallurgical changes that affect the rupture strength intersectthe strength-temperature regressioncurve at 1200°F occur above this temperature. The quadratic curves for the (649°C). The resulting curves for average and minimum average and minimum rupture strengths were calculated 100,000-hour rupture strength shown in Figure 4E of this stan- using least squares techniques. dard are generally equal to or below the strength-temperature regression curves of Data Series 6S2. A.5.7 25Cr-35Ni-HP-MODIFIED A.5.5 Ni-Fe-Cr (ALLOY 800H) Stress curves HP-modified tubing for cast are not The Larson-Miller curves for Alloy 800H in Figure 4R included. This material is proprietary to individual found- weredeveloped from 91rupture-test data points from one ries. As such, i t is not feasible to develop generic stress source.Thesetests used samples from six heats of Alloy data which would apply to all manufacturers of this mate- 800H (with appropriate chemistry and grain size) that were rial. made in bar, plate, and tubeproduct forms. All tests were run at temperatures of 1800°F (982°C) or lower, except for one A 5 8 9Cr-1Mo-Va STEEL that was run at 1900°F (1038°C). The linear curves for the average and minimum rupture strengthswere calculated The maximum limit for this material has been restricted to using least-squares techniques. Using a quadratic curve did 1200°F (650°C) dueto the lack of stress data above this tem- not appreciably improve the fit of these data. perature (See Figure 4K).COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 107. ~~ ~~ ~ A P I STD*530 9b 0732290 05b339b 222 m APPENDIX B-DERIVATION OF CORROSION FRACTION AND TEMPERATURE FRACTION B.l General t, - CA = t, - (1-f )CA The 1958 version of this document containeda method for This thickness is less than t,; therefore, at the end of the designing tubes in the creep-rupture range. The method took design life, the stress would be greater than S, , and the rate into consideration the effects of stress reductions produced of using up the rupture lifewould be high. If the value off is by the corrosion allowance. In developing this design method, selected properly, the integrated effect of this changing rate the following ideas were used. of using up the rupture life would yield a rupture life equal to At temperatures in the creep-rupture range, the life of atube the design life. The corrosion fraction, , given in Figure 1 is f is limited. Therate of using up the life depends on temperature such a value. and stress. Under the assumption of constant temperature, the The curves in Figure 1 were developedby solving the non- rate of using up the life increases as the stress increases. In linear equation that results from applying the linear damage other words, the tube will last longer if the stress is lower. rule. Figure 1 can be applied to any design life,provided If the tube is corroding or oxidizing, the tube thickness will only that the corrosion allowance, CA, and rupture allowable decrease in time; therefore, under the assumption of constant stress, S,, are based on the same design life. pressure, the stress in the tube will increase in time. As a result, the rate of using up the rupture life will increase in time. also 8.2 LinearDamageRule An integral of this effect over the life of the tube can be Consider a tube that is operated at a constant stress,S, and solved graphically in the 1958 version of API Recommended a constant temperature, 8, for a period of time, AL. Corre- Practice 530 and developedusing the linear damage rule (see sponding to this stress and temperature is the following rup- B.2). The result is a nonlinear equation that provides the ini- ture life: tial tube thickness for various combinations of design tem- perature and design life. L, = Lr ( S , 0) The concept of corrosion fraction used in 2.4 and derived The fraction ALIL,, would then be the fraction of the rupture in this appendix is developed from the same ideas and is a life used up during this operating period. After M operating simplified method of achieving the same results. periods, each with a corresponding fraction- Suppose a tube has an initial thickness, r,, calculated using Equation 4. This is the minimum thickness required to achieve the design life without corrosion. If the tube does not (?)&= 1 , 2 , 3,...,M corrode, the stressin the tube will always equal the minimum rupture strength for the design life, S, This tube should fail -the total fraction of the rupture life used up, F (also known after the endof the design life. as the life fraction), would be the sum of the fractions used in If this tube were designed for use in a corrosive environ- each period: ment and had a corrosion allowance of CA, the minimum thickness could be set as follows: t,,, = t.?+ CA The stress would initially be less than S,. After operating I n developing this equation, no restrictions were placed on for its design life, the corrosionallowance would be used up, the stress and temperature from period to period. It was and thestress would only then equal S,. Since the stress assumed only that during any one period the stress and tem- would always have been lower than S, , the tube would still perature were constant. The life fraction therefore provides a have some time to operate before it failed. wayof estimating the rupture life used up after periods of Suppose instead that the initial thickness was set as follows: varying stress and temperature. The linear damage rule asserts that creep rupture will occur t, = t, + f CA when the life fraction totals unity, that is, when F(M) = 1. In this equation, f is a fraction less than unity. The stress The limitationsof this rule are not well understood. Never- would initially be less than S,, and the rate of using up the theless, the engineering utility of the rule is widely accepted, rupture life would be low. At the end of the design life, the andthe rule is frequently used in both creep-rupture and tube thickness would be as follows: fatigue analysis [References 14, 15, 16, 171. 1o1COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 108. 102 API STANDARD 530 8.3 Derivation of Equation for Corrosion Fraction With continually varying stress and temperature, the life Where: fraction can be expressed as an integral: P, = rupture design pressure. D, = outside diameter. [(T)= thickness expressed as a function of time. Where: In general, the rupture design pressure (operating pres- sure) is also a function of time; however, like temperature, it T = operating life. is assumed to be constant for the purposes of tube design. L, = L, (S, 0) The thickness is determined by the following equation: = rupture life at stress, S, and temperature, 8. t = time. r(z) = to -RT (B-6) In general, both the stress, S, and the temperature, 8, are func- Where: tions of time. to = initial thickness. The rupture life and the stress can berelated as follows, at R = corrosion rate. least over limited regions of stress or time (see A.4): Calculating F ( r ) is then simply a matter of substituting L , = mS" Equations B-S and B-6 in Equation B-4 and integrating. This integration cannot be done i n closedform; a simplifying Where: assumption is needed. m and n = material parameters that are functions of tem- Let r, be the thickness calculated from S, as follows: perature. n = rupture exponent. For a specified designlife, Ld, andcorresponding rupture To a first approximation, strength, Sr - I - L, = m ; S. (B-7) so, Substituting Equations B-S, B-6, and B-7 in Equation B-4 and integrating results in the following equation: m = L,S; Hence, (B-3) At T = L,, F(&) should equal unity; that is, the accumulated damage fraction should equal unity at the end of the design Using Equation B-3 in Equation B-2, the life fraction can life. Using F ( r ) = 1 and T = L , in Equation B-8 results in the be expressed asfollows: following equation: T S(t) "dy F(T)=so [TlL, (B-4) Where: Now let to= r,r + fCA and B = CAIt,, where CA = RL,;that is, the corrosion allowance is defined as being equal to the S(t) = stress expressed as a function of time. corrosion rate times the design life. With these changes, This integral can be calculated once the temperature and Equation B-9 becomes an equation for f as follows: stress history are known, but in general this calculation is dif- ficult to perform. For the purposes of this development for tube design, the temperature is assumed to beconstant. (This assumption is relaxed in B.5.) The remaining variable is For given values of B and n, Equation B-10 can be solved therefore the stress as a function of time. This is given by the for the corrosionfraction, f . Thesolutionsareshown in mean-diameter equation for stress as follows: Figure 1.COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 109. ~~ A P I STDE530 Yb M 0732290 05bL398 O T 5 . m CALCUlATlON OF HEATER-TUBE THICKNESS PETROLEUM REFINERIES IN 1O3 6.4 Limitations of the Corrosion Fraction relate the rupture life to both stress and temperature. This equation can be derived by means of the Larson-Miller In addition to the limitations of the linear damage rule parameter plot. When this plot is a straight line (or when the mentioned in B.2, the corrosion fraction has other limita- curve can be approximated by a straight line), the stress and tions. For the derivation, the temperature, pressure, and cor- the Larson-Miller parameter, P, can be related as follows: rosion ratewereassumed to be constant throughout the operating life. In an operating heater, these factors are usu- S =AICbP (B-11) ally not constant; nevertheless, the assumptions of constant Where: pressure, temperature, and corrosion rate are made for any tube design. The assumptions are therefore justified in this A, b = curve-fit constants. case, since the corrosion fraction is part of the rupture design P = e(ct I O ~ L , ) x 10-3. procedure. (The assumption of constant temperature can be e = temperature, in absolute degrees. relaxed as shown in B.5.) c = Larson-Miller constant. The derivation of the corrosion fraction also relies on the L, = rupture time, in hours. relationshipbetweenrupture life and stress expressed in Equation B-3. For those materials that show a straight-line Solving Equation B-11 for L , yields the following equa- Larson-Miller parameter curve in Figures 4A-4S this repre- tion: sentation is exact. For those materials that show a curvilinear Larson-Miller parameter curve, using Equation B-3 is equiv- L = - r l A 10 S (-) 10uu/bH (B-1 2) alent to making a straight-line approximation of the curve. To minimize the resulting error, the values of the rupture Using Equation B-12, the life fraction given by Equation B-2 exponent shown in Figures 4A-4S were developed from the becomes the following: minimum 60,000- and 100,000-hour rupture strengths (see A.4). In effect, this applies the straight-line approximation to a shortersegment of the curved line and minimizes the F(T ) = f lo( i) lWo/btl dt (B-13) error over the usual range of application. Finally, the mathematical approximation of Equation B-7 Where: was used. A more accurate approximation is available; how- S = stress as a function of time. ever, when it is used, the resulting graphical solution for the 8 = temperature as a function of time. corrosionfraction is more difficult to use. In addition, the resulting corrosion fraction differs from that given in Figure The thickness, which is also a function of time, canbe 1 by less than one half of 1 percent. This small error and the expressed as follows: simplicity of using Figure 1 justify the approximation of Equation B-7. B.5 Derivation of Equation for Temperature Fraction Where: Since tube design in the creep-rupture range is very sensi- r,, = initial thickness. tive to temperature, special consideration should be given to At = thickness change in time T cases in which a big difference exists between start-of-run T = duration of operating period. and end-of-run temperatures. In the derivation of the corro- sion fraction B.3, the temperaturewas assumed to remain For this derivation, let constant. The corrosion fraction can be applied to cases in which the temperature varies if an equivalent temperature (B-14) can be calculated.The equivalent temperature should be such that a tube operating at this constant equivalent temperature p = -t (B-15) T would sustain the same creep damage as a tube operating at the changing temperature. Equation 6 can be used to calcu- Therefore, late an equivalent temperature for a case in which the tem- t(t) = to( 1 - B o ) (B-16) perature changes linearly from start-of-run to end-of-run. Equation B-3 was developed to relate the rupture life, L, , Using Equations B-S and B-16 and the approximation given to the applied stress, S. A comparable equation is needed to by Equation B-7, the stress can be expressed as follows:COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 110. A P I STDx530 9b 0732290 0563399 T 3 1 m 104 API STANDARD 530 From Equation B-20, the resulting life fraction is as follows: n,/( 1 + Di.) F( T ) = II loc[ (-) 1 (3) - B p A 1 ] Tdp (B-22) Where: Equating Equations B-20 and B-22 and dividing out com- mon terms yields an integral equation for the parameter h: If a linear change in temperature occurs during the time then the temperature, 0, can be expressed as a function of time, z, as follows: Where: 0, = initial temperature, in absolute degrees. A0 = temperature change in time T For given values for &,A, no,B, and D,Equation B-23 can be = Teor-Tmr solved numerically for h. Using h. and Equations B-18andB- 21, the equivalent temperature is calculated as follows: Let (B-18) (B-24) Using Equations B-15 and B-18, the equation for tempera- ture becomes the following: The parameter h is the temperature fraction, f ~in, 2.8. The solutions to Equation B-23 can be approximated by a €)(T) = €lO(l D p ) t (B- 19) graph if the given values are combined into two parameters as follows: Using Equations B-17 and B-19, Equation B-13 can be writ- ten as follows: Where: Using these two parameters, the solutions to Equation B-23 are shown in Figure 2. 1000 The constantA in Table 3 is one of the least-squares curve- no = - ben fit constants, A and b, in the equation S = Al&bp,where P is the Larson-Miller parameter and S is the minimum rupture This is the rupture exponent at the initial temperature, 8,. strength. For materials that have a straight Larson-Miller The aim of this analysis is to find a constant equivalent tem- parameter curve, A can be calculated directly from any two perature, 0,, between 0, and 0, t A0 such that the life fraction at points on the curve. For all other materials, a least-squares the end of the period T with the linearly changing temperature approximation of the minimum rupture strength was calcu- will be equal to the life fraction with the equivalent temperature. lated in the stress region below the intersection of the rupture This equivalent temperature canbe expressed as follows: and elastic allowable stresses, since this is the region of most applications. For the purpose of calculating the temperature 0, = 0,( 1 t DA),O C h < 1 (B-21) fraction, this accuracy is sufficient.COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 111. API STD*530 96 D 0732290 0563400 5 8 3 M APPENDIX C-CALCULATION OF MAXIMUM RADIANT SECTION TUBE SKIN TEMPERATURE C.l General pb = absolute viscosity of fluid at bulk temperature, in pounds per foot per hour (pascal-seconds). Thisappendix provides a procedure for calculating the p = absolute viscosity of fluid at wall temperature, in , maximum radiant section tube metal (skin) temperature. pounds per foot per hour (pascal-seconds). Correlations for estimatingthe fluid-film heat-transfer coeffi- h, = heat-transfer coefficient, vapor phase, in British ther- cient aregiven in C.2. A method for estimating maximum the mal units per hour per square foot per degree Fahr- local heat flux is given in C.3. The equations used to calcu- enheit (watts per square meter per degree Celsius). late the maximum tube skin temperature and the temperature Tb = absolute bulk temperature of vapor, in degrees Rank- distribution through the tube wall are described in C.4. The ine (kelvins). sample problem in C S demonstrates the use of these equa- T, = absolute wall temperature of vapor, in degrees Rank- tions. ine (kelvins). G = mass flux of fluid, in pounds per hour per square foot C.2 Heat-Transfer Coefficient (kilograms per second per square meter). A value necessary for calculatingthe maximum tube metal C = heat capacity of fluid at bulk temperature, in British temperature is the fluid heat-transfer coefficient at the inside thermal units per per pound degree Fahrenheit wallof the tube. Althoughthe following correlations are (joules per kilogram per degree Celsius). extensively used and accepted in heater design, theyhave inherent inaccuracies associated with all simplified correla- All of the material properties except p w are evaluated at the tions that are used to describe complex relationships. bulk fluid temperature. To convert absolute viscosity in centi- For single-phase fluids, the heat-transfer coefficient is cal- poise to pounds per foot per hour, multiply by 2.42. To con- culated by one of the two equationsbelow, in which Re is the vert centipoise to pascal-seconds, divide by 1000. Reynolds number and P r is the Prandtl number. No correla- For two-phase flows,the heat-transfer coefficient canbe tionis included for the heat-transfer coefficient in laminar approximated using the following equation: flow, since this flow regime is rare in process heaters. There is inadequate information for reliably determining the inside h, = h,W, t h,W, (C-5) coefficient in laminar flow for oil in tube sizes that are nor- Where: mally used in process heaters. For liquid flow with Re 2 10,000 [Reference 181, h,p = heat-transfer coefficient, two phase, in British ther- mal units p e r hour per square foot per degree Fahr- O.14 h, = 0.023(&) ReoxPr"3 enheit (watts per square meter per degree Celsius). W, = weight fraction of liquid. For vapor flow with Re 215,000 [Reference 191, W, = weight fraction of vapor. 0.5 h, = 0.021(&) R e O " P r o " ( ~ ) The liquid andvapor heat-transfer coefficients, h, and h, should be calculated usingthemixed-phasemassfluxbut using the liquid and vapor material properties, respectively. DiG Re = - (C-3) ph Note: I n twophase flow applicationswheredispersed flow or mist flow regimesoccurduetoentrainment of liquid droplets i n thevapor (cg. towards the outlet of vacuum heaters), the heat transfer coefficient maybe calculated using the correlation for vapor phase per Equation C-2, based on Where: the total flow rate. rather than approximated by Equation C-5. h, = heat-transfer coefficient, liquid phase, in British ther- mal units per hour per square foot per degree Fahren- C.3MaximumLocalHeatFlux heit (watts per square meter per degree Celsius). The average heat flux in the radiant section of a heater (or k = thermal conductivity of fluid at bulk temperature, in in a zone of the radiant section) is equal to the duty in the British thermal units perhourper foot per degree section or zone divided by the total outside surface area of Fahrenheit (watts per meter per degree Celsius). the coil in the section or zone. The maximum local heat flux Di inside diameter of tube, in feet (meters). = at any point in the coil can be estimated from the average 105COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 112. ~ A P I STD*530 96 W 0732290 05bL4OL 4 L T W 106 API STANDARD 530 heat flux. The maximum localheatflux is used with the The tube metal temperature factor, F,, will be less than 1.0 equations in C.4 to calculate the maximum metal temperature. near the coil outlet or in areas of maximum tube metal tem- Localheat fluxes vary considerably throughout a heater perature. It will be greater than 1.0 in areas of lower tube because of nonuniformities around and along each tube. Cir- metal temperatures. For most applications, the factor can be cumferential variations result from variations in the radiant approximated as follows: heat flux produced by shadings of other tubes or from place- ment of the tubesnext to a wall. Conduction aroundthe tubes and convection flows of flue gases tend to reduce the circum- ferential variations in the heat flux. The longitudinal varia- Where: tions result from proximity to burners and variations in radiant firebox and bulk fluid temperature?. In addition to T, = average flue-gas temperature in the radiant section, variations in the radiant section, the tubes in the shock sec- in degrees Rankine (kelvin). tion of a heater can have a high convective heat flux. T, = tube metal temperature at the point under consider- The maximum heat flux at any point in a coil can be esti- ation, in degrees Rankine (kelvin). mated as follows: T,, = average tube metal temperature in the radiant sec- tion, in degrees Rankine (kelvin). q m = FcFLFTqu + q c (C-6) The convective heat flux in most parts of a radiant section Where: is usually small compared with the radiant heat flux. In the q, = maximum radiant heat flux, outside surface, in Brit- shock section, however, the convective heat flux can be sig- ish thermal units per hour per square foot (watts per nificant; it should therefore be added to the radiant heat flux square meter). when the maximumheatfluxin the shock section is esti- F, = factor accounting for circumferential heat-flux vari- mated. ations. FL = factoraccountingfor longitudinal heat-fluxvaria- C.4 Maximum Tube Metal Temperature tions. In addition to the heat-transfer coefficient and the maxi- F , = factor accounting for the effect of tube metal tem- mum heat flux, the temperature profile of the fluid in the coil perature on radiant heat flux. is necessary for calculating the maximum tube metal temper- qa = average radiant heat flux, outside surface, in British ature in the radiant section of the heater. This profile, which thermal units per hour per square foot (watts per is often calculated by the heater supplier, defines the varia- square meter). tion of the bulk fluid temperature through the heater coil. For qe = average convective heat flux, outside surface, in operation at or near design, the design profile can be used. British thermal units per hour per square foot (watts For operation significantly different from design, a bulk tem- per square meter). perature profile must be developed. The circumferential variation factor, F,, is given as a func- Once the bulk fluid temperature is known at any point in tion of tube spacing and coil geometry in Figure C-l. The the coil, the maximum tube metal temperature can be calcu- factor given by this figure is the ratio of the maximum local lated as follows: heat flux at the fully exposed face of a tube to the average T, = T, + ATf + ATc + ATw (C-8) heatflux around the tube. This figure was developed from considerations of radiant heat transfer only. As mentioned above, influences suchasconductionaround the tube and ATl = (-) h D,-2tc D O (C-9) convective flows of flue gases act to reduce this factor. Since (C-10) these influences are not included in this calculation, the cal- culated value will be somewhat higher than the actual maxi- (C-11) mum heat flux. The longitudinal variation factor, FL, is not easy to quan- Where : tify.Values between 1.0 and 1.5 are most often used. In a firebox that has a very uniform distribution ofheatflux, a T,,, = maximum tube metal temperature, in degrees Fahr- value of 1.0 may be appropriate. Values greater than 1.5 may enheit (degrees Celsius). be appropriate in a firebox that has an extremely uneven dis- Tb = bulk fluid temperature, in degrees Fahrenheit tribution of heat flux (for example, a long or a tall, narrow (degrees Celsius). firebox with burners in one end only). ATl = temperature difference across fluid film, in degreesCOPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 113. ~ API S T D x 5 3 0 9b 0 7 3 2 2 9 0 05bl1402 356 m CALCULATION OF THICKNESS HEATER-TUBE PETROLEUM REFINERIES IN 107 4.0 3.5 L" 3.0 - L O u ,m - - - 3 m X al c - m F 2.5 2 2 5 E G 2.0 1.5 1 .o 1.o 1.5 2.0 2.5 3.0 Lenterllne nommal tube spaclng/tube outslde diameter Notes: Note 1 : Curve 1 = double row against wall, triangular spacing; Curve 2 = double row with equal radiation from both sides and two diame- ters between rows, equilateral spacing; Curve 3 = single row against wall; and Curve 4 = single row with equal radiation from both sides. Note 2: These curves arevalid when used with a tube-center-to-refractory-wall spacing of I/* times the nominal tube diameter. Anyappre- ciable variation from this spacing must be given special consideration. Note 3: These curves do not consider convection heat transfer to the tubes, circumferential heat transfer by conduction in the tube wall, or variations in heat flux in different zones of the radiant section. Note 4: These curves arebased on the work of H.C. Hottel, as reported on page 69 of Reference 18. Figure C-1-Ratio of Maximum Local to Average Heat FluxCOPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 114. A P I STD*530 96 m 0732290 0563403 292 m 108 API STANDARD 530 Fahrenheit (degrees Celsius). Flowrate = 50,000 pounds perhour (6.3 kilograms per ATc = temperature difference across coke or scale, in second) [total liquid plus vapor]. degrees Fahrenheit (degrees Celsius). Tb = 520°F (270°C). ATw = temperature difference across tube wall, in degrees 4. = 10,000 Btu/hr-ftz (31,500 W/rn2). Fahrenheit (degrees Celsius). The properties ofthe liquid at the bulk temperature are as 9m = maximum radiant heat flux, outside surface, in follows: British thermal units per hour per square foot (watts per square meter). p = 2 centipoise = 4.84 Ib/hr-ft (2.0 x Pa-S). h = fluid-film heat-transfercoefficient, in British ther- k = 0.0672 Btuihr-ft-"F (0.1163 W/m-"C). mal units per hour per square foot per degree Fahr- C = 0.68 Btu/lb-"F (2850 J/kg-"C). enheit (watts per square meter per degree Celsius). The properties of the vapor at the bulk temperature are as fol- D, = outside diameter of tube, in feet (meters). lows: D,= inside diameter of tube, in feet (meters). p = 0.007 centipoise = 0.017 Ib/hr-ft (7.0 x 10-6 Pa-S). tc = coke or scale thickness, in feet (meters). k = 0.020 Btu/hr-ft-"F (0.0346 W/m-"C). kc = thermal conductivity of coke or scale, in British thermal units per hour per foot per degree Fahren- C = 0.572 Btu/lb-"F (2395 J/kg-"C). heit (watts per meter per degree Celsius). Fromthe inside diameter, theflow area is equal to 0.0871 t, = average tube thickness, in feet (meters). square foot (8.091 x squaremeters).Using the total flow kv= thermal conductivity of tube metal, in British ther- rate, mal units per hourper foot per degree Fahrenheit G = (50,000/0.0871) (watts per meter per degree Celsius). = 5.74 x los Ib/hr-ft2 In Equations C-10 and C-11, the denominators within the In SI units, parenthesesarethe mean diameters of the coke layer and tube, respectively. The effect of coke or scale on the tube G = 6.3/(8.091 x ~ O - ~ ) metal temperature can be estimated using Equation C-10. = 778.6 kg/s-m2 The thermal conductivity of the tube material used in The Reynolds number (Equation C-3) is as follows: Equation C-11 should be evaluated at the average tube wall temperature. For casttubes,the nominal as-cast thickness For liquid, should be used for t. in Equation C-11. C.5 Sample Calculation In SI units, The following sample calculation demonstrates to use how the equations given in the previous paragraphs, (the SI con- versions in parentheses are approximate). In the heater under consideration, themedium carbon steel tubes are in a single row against the wall. Other aspects of For vapor, the heater configuration areas follows: Tube spacing = 8.0 inches = 0.667 foot (203.2 millime- ters). In SI units, D, = 4.5 inches = 0.375 foot (114.3 millimeters). ta = 0.25 inch = 0.0208 foot (6.4 millimeters). Di = 4.0 inches = 0.333 foot (101.5 millimeters). r, = O inches (O millimeters). k,,,= 24.4 Btu/hr-ft-"F (42.2 W/m-"C) at an assumed tube The Prandtl number (Equation C-4) is as follows: metal temperature of 720°F (380°C) [from Table 1, For liquid, Reference 71. The flow in the tubes is two phase with 10 weight percent vapor. Other operating conditions are follows: asCOPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 115. ~ A P I STD*530 96 0732290 OSbL404 L29 CALCULATION OF THICKNESS HEATER-TUBE IN PETROLEUM REFINERIES 1o9 In SI units, h, = (0.90)h, + (0.10)hV = (0.90)(87.7) + (0.10)(377) = 116.6 Btu/hr-ft*-"F In SI units, For vapor, h,p = (0.90)(498) + (0.10)(2141) = 662.3 W h 2 - " C The ratio of tube spacing to tube diameter is as follows: In SI units, - = 1.78 4.5 In SI units, Assume that for the liquid, (E) O. I 4 = 1.1 203.2 - 1.78 " 114.3 From Figure C-1, F, = 1.91. Assume that for this heater, Assume that for the vapor, FL = 1.1, F , = 1.0, and 4, = O (that is, there is no convective Tb Os heat flux at this point). Using Equation C-6, (7) 0.91 = W/ q,,, = (1.91)(1.1)(10,000) These assumptions will be checked later. Using Equation = 21,000 Btu/hr-ft* c-1, In SI units, (3.95 X 104)0~"(49.0)"~33 (1.1) qm= (1.91)(1.1)(31,500) = 66,200 W/m2 = 434.7( $, The temperature difference through each part of the sys- tem can now be calculated. From Equation C-9 for the fluid Using Equation C-2, film, (3 h, = 0.021 - (1.13 x 107)".H(0.485)"4 (0.91) = 6281 (6) In SI units, 66,200 114.3 = 113"c Hence, ATf = ( % E d (m, From Equation C-1 1 for the tube wall, h, = 4 3 4 . 7 ( O X 2 ) = 87.7Btu/hr-ftZ-"F 0.333 ATw, =r(21,000)(0.0208)1F0.3750.375 ] = 19°F c 24.4 0.0208 - h , = 6 2 8 1 ( E 0 ) = 377Btu/hr-ft2-"F 0.333 In SI units, ATw =r(66, 42.2 IF114.3- 6.41 i 200)(6.4) 114.3 1 x 10-3 = lloc In SI units, Using Equation C-8, the maximum tube metal temperature is as follows: h , = 6281( w6) W/m2-"C 0.1015 = 2141 T,,,= 520 + 203 + 19 = 742°F In SI units, The two-phase heat-transfer coefficient can then be calcu- lated using Equation C-5: T,,, = 270 + 113 + 11 = 394°CCOPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 116. 110 API STANDARD 530 Checking the assumedviscosityratio, at the oil-film tem- In SI units, perature calculated above, 520 + 203 = 723°F (270 + 113 = 383"C), theviscosity is 1.1 centipoise = 2.66 pounds per (: s J " (383 + 273 - 270 + 273)"5 = ( 0.83)0.5= 0.91 hour-foot (1.1 x pascal-seconds). So for the liquid, Both values are close to the values assumed for the calcu- (3"144.84 = ( 1.82))14= 1.09 = (a) lation of h, and h,, so no additional work is needed. The mean tube-wall temperature is as follows: In SI units, 19 520 + 203 + - = 732°F 0.14 2 .I4 = ( 1-82)0~4 1.o9 = In S1 units, For the vapor, 11 2 7 0 + 1 1 3 + - = 388°C 2 = = (0.83)05 0.91 This is close to the temperature assumed for the tube conduc- tivity, so no additional work is required.COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 117. A P I STD*530 96 m 0732290 0563406 TT3 m APPENDIX D-THERMAL-STRESS LIMITATIONS (ELASTIC RANGE) D.l General ence 7, can be approximated for thermal stress as follows (see D.5 for derivation): In heater tubes, the thermal stress of greatest concern is the one developed by the radial distribution of temperature through the thickness.This stress can becomeparticularly For ferritic steels, significant in thick stainless steel tubes exposed to high heat fluxes. Sth.lrm2 (D-5) There are two limits for thermal stress; both are described in For austenitic steels, Reference 7, Paragraphs 4-134 and 5-130. These limits apply only in the range; in the elastic appropriate an range, rupture S,h<irn2 1.8Sy ( W limit for thermal stress has not been established. Both the primary plus secondary stress limit S f h fim and the thermal-stress ratchet limit S,,, shallbe met if the tube is D.2 Equation for Thermal Stress designed for the elastic range. v v The following equation gives the maximum thermal stress in a tube: D.4 Derivation o Limits on Plus f Primary S,, = - 2Y2 In Y - 11 1 (D-1 1 Secondary Stress Intensity The limit on primary plus secondary stress intensity can Where: be expressed symbolically as PL + P, + Q S 3S,.For this application, Q is the maximum circumferential thermal X= stress, S,, given by Equation D-l. For tubes with an internal pressure [Reference 71, a = coefficient of thermal expansion. 2Y2 E = modulus of elasticity. pL + P , P , - (Y2 - 1) v = Poissons ratio. AT = temperature difference acrosstube wall. Where: Y = D, /Di, ratio of outsidediameter to actual inside PL = local primary membrane stress. diameter. Pb = primary binding stress. q o = heat flux on outside surfaceof tube. P, = elastic design pressure. k = thermal conductivity of the steel. Y= D,/D,, ratio of outside to actual inside diameter. The material properties a, E , v, and k shall be evaluated at If Spmis theprimary membranestress intensity given by the mean temperature of the tube wall. The average wall Equation D-7 [Reference 71, thickness shall alsobe used in this equation (see 2.7). D.3 Limits on Thermal Stress The limitation on primary plus secondary stress intensity I t can then be easily shown that, to a first approximation and in Paragraph 4-134, Reference 7 , can be approximated for providing an upper bound, thermal stress as follows(see D.4 for derivation): For ferritic steels, P, + P , = YS,, S,,,+rm, (2.0 - 0.67Y)Sy (D-3) I n Reference 7, S,,,is the allowable membrane stress inten- For austenitic steels, sity.For ferritic steels above about 650°F(340°C), S,, is Sl,,fzrnl (2.0 - 0.90Y)S, E equal to two-thirds the yield strength, Sy, so 3Sm= 2 S y . For (D-4) austenitic steels above about 500°F (260°C),S, is 90 percent Where: of S,, so 3S, = 2.7s". Heater tubes usually operate above these temperatures. S, = yield strength. Combining all of this, the primary plus secondary stress The thermal-stress ratchet limit in Paragraph 5-130, Refer- intensity limit on thermal stress can be expressed as follows: 111COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 118. 112 API STANDARD 530 given by these equations, then the more exact form of Equa- tions D-8 or D-9 shall be used with the primary membrane stress intensitygiven by Equation D-7. Also, if the tube For austenitic steels, thickness is arbitrarily increased over the thickness calcu- lated in 2.3, then the primary membrane stress intensity shall be calculated using the actual average thickness, and Equa- tion D-8 or Equation D-9 shall be used to calculate the ther- mal-stress limit. Where: D.5 Derivation of Limits on Slh.lim, = maximum value permitted for the thermal Thermal-Stress Ratchet stress S,. The limit set to avoid thermal-stress ratchet can be For ferritic steel heater tubes designed according to this stan- expressed as follows [Reference 71: dard, ./hZ = 4(s- s p m (D-12) SPm O.67Sy S (D-10) For ferritic steels, S = S,, For austenitic steels above about For austenitic steel tubes, 500°F (260°C), S = 1.5 (0.9Sy) = 1.35SY. As before, Spmis derived from Equation D-7. Using Equation D-10 or Equa- SPm 0.90SY S (D-11) tion D-11, this limit can be approximated as follows: The thermal-stress limit can therefore be approximated as For ferritic steels, follows: Srh , ! l m 2 0: 1.335) For ferritic steels, S l h . /¡ml e (2.0 - O.67Y)Sy For austenitic steels, Sth l l m 2 1.8sy For austenitic steels, S l h ./¡ml (2.0 - 0.90Y)Sy As with the limits developed in D.4, these limits are approxi- mate. If the thermal stress exceeds this limit or if the tube The limits expressed by these equations are simple and thickness is arbitrarily increased, the exact limit expressed by appropriate. If the thermal stress is less than this limit, the Equation D-12 shall beused with the primary membrane design is approximate. If the thermal stress exceeds the limit stress intensity given by Equation D-7.COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 119. APPENDIX E-ESTIMATION OF REMAINING TUBE LIFE E.l General an estimate of the expected life at specified operating condi- tions. Figures4A-4S and the ideasdiscussed in Appendix B have uses other than for the design ofnew tubes. They can also be used to help answer reratingand retirement questions E.2 Estimation of Accumulated Tube about existing tubes that have operated in the creep-rupture Damage range. appendix This describes how tube damage and Since the concepts required to estimate damage are devel- remaining life canbe estimated. Because of the uncertainties oped elsewhere in this practice, they are not repeated here. involved in thesecalculations,decisions about tube retire- The calculation procedure canbest be explained by working ment should not be based solely on the results of these calcu- through an example. For this example, the following condi- lations.Otherfactorssuch as tube thickness or diameter- tions are assumed: strainmeasurementsshould be primary considerations in decisions about tube retirement. Material = 8Cr-1ONi-Cb (Type 347) There are three primary areas of uncertainty in these cal- stainless steel culations.First, to estimate the accumulated tube damage Outside diameter = 6.625 inches (the life fraction used up), the operating history mustbe (168.3 millimeters) approximated. This history must include the operating pres- Initial minimum thickness= 0.268 inch sure, the tube metal temperature, and the corrosion rate. The (6.8 millimeters) uncertainties in thesefactors, particularly the temperature, can have a significant effect on the estimate. Second, knowl- It is also assumed that the operating history of the tube can edge of the actual rupture strengthof a given tube is not pre- be approximated as shownin Table E-l. (The S1 conversions cise. The example calculation in E.2 demonstratesthe effects are approximate.) of thisuncertainty. Finally, the tube damage. calculation The operating periods need not be of uniform length. In an makes use of the linear damage rule described in B.2. As actual heater, neither the operatingpressure northemetal mentioned in B.2., the limitations of the hypothesis are not temperature is uniform. Even so, for this calculation, they well understood. In spite of all these uncertainties, the esti- must be assumed to be uniform during each period. Theval- mation that is made using the proceduredescribed in this ues chosen for each period should represent typical values. appendix may provide information that will assist in making The length of the operating period chosen depends onhow decisions about tube rerating and retirement. the pressure and temperature vary. The essence of this calculation procedure can be outlined The historyofthe tube thickness must be approximated. as follows: The operating history is divided into periods of This historycanusuallybe developed from thickness mea- time in which the pressure, metal temperature, and corrosion surements made before the initial start-up and during routine rate are assumed constant. For each of these periods, the life heater-tube inspections. For all of these estimates, it is fraction used up is calculated. The sum of these calculated assumed that the outside diameter remains constant. life fractions is the total accumulated tube damage. The frac- This information can be used to calculate the life fractions tion remaining is calculated by subtracting this sum from shown in Table E-2. unity. Finally, the remaining life fraction is transformed into For a corroding tube, an equation similar to Equation B-8 Table E-1-Aooroximate Ooeratinn Historv Operating Pressure Minimum Metal Temperature Tube Pounds per Thickness Operation Duration Square Inch Megapascals Degrees Degrees End Beginningrenheit Gauge (years) Period (gauge) Millimeters Inches Inches Millimeters 1.3 1 3.96 75 I200 649 0.268 6.81 0.252 6.40 2 4.27 0.6 620 I230 6656.20 0.252 0.244 6.40 3 I220 2.1 4.07 5 90 660 6.20 0.244 0.217 5.51 1 5.5 4 0.217 2.0 665 630I230 4.34 0.190 4.83 113 COPYRIGHT American Petroleum Institute Licensed by Information Handling Services
  • 120. A P I STD*530 96 0732290 05bL409 700 114 API STANDARD 530 Table E-2-Life Fractions for Each Period Larson-Miller Values Rupture Time Based on Rupture Time Based on Average Stress Average Minimum Minimum Strength Average Strength OperatingDegrees Degrees Degrees per DegreesPounds Life Life Years YearsCelsiusFahrenheitCelsiusFahrenheit Inch Period Sauare19.06 34.32 148.52 7045 2 7973 54.91 33.90 18.83 34.66 19.25 0.02 13.1 35.8 0.05 3 8213 56.66 33.80 34.55 18.77 15.0 19.19 0.14 42.1 0.05 9985 4 13.1 0.43 18.41 4.7 33.90 18.83 - 0.15 - Accumulated damage = 0.64 0.23 can be developed for the life fraction; however, this isnot been used. If the actual strength is in the middle of the scatter necessary, since sufficient accuracy can be achieved for this band (near the average rupture strength), then only 23 per- calculation by using the average stress for each period (that cent ofthe tube life has been used. If the actual rupture is, the average of the stress at the beginning and at the end of strength is higher, even less of the tube life has been used. the operating period). The effect of the uncertainty about the operating tempera- The minimum and average Larson-Miller values in Table E-2 ture can also be evaluated. Supposethe actual metal tempera- are determined from the average stress using the Larson-Miller ture of this tube were 9°F (SOC) higher than that shown in parameter curves for minimum and average rupture strength in Table E-l. To estimate the effect of this difference, the life- Figures 4A4S. For this example, Figure 4Q was used. fraction calculations i n Table E-2 have been made with the With these Larson-Miller values and the metal tempera- slightly higher temperature. The corresponding accumulated ture foreachperiod,theexpressionfor the Larson-Miller damage fractions are 0.81 and 0.28, respectively. These parameter was solved for the rupture time. This expression is should be compared withthe values 0.64 and 0.23, which at the top of Figures 4A-4S. Since this expression gives the were calculated first. rupture time in hours, the value must be converted to years. The resulting times based on the minimum rupture strength E.3 Estimation of Remaining Tube Life and the average rupture strength areshown in Table E-2. Thefollowingexampleillustrates howto calculate the As in E.2,thiscalculationprocedure is bestexplained by minimum-strength rupturetime for the first operating period. example. The example used is the one summarized in Tables E- The equation to be solved is as follows: l and E-2. The life fraction remaining for this is as follows: tube 34.32 = (1200 + 460)(15 + l o g , ) x 1p3 Minimum rupture strength: 1 - 0.64 = 0.36 Average rupture strength: 1 - 0.23 = 0.77 In SI units, These fractions must be translated into expected life at the 19.06 = (649 + 273)(15 + lo&,) x 10" specified operating conditions. The following related questions can be asked at this point: or, a. What isthe estimated life at a given operating pressure, IO&, = 5.67 metal temperature, and corrosion rate? L, = 4.73 x lo5 hours = 54.0 years b. For a specified operating pressure and corrosion rate, what temperature limit must be imposed for the tube to last a min- The life fractions are simply the durationof the operating imum period of time? period divided by the rupture time that corresponds to that c. How much should the operating pressure or metal temperature period. Using the minimum-strength rupture time calculated be reduced to extend the expected life bygiven percentage? a above, the fraction for the first line in Table E-2 is 1.3/54.0 = 0.02. The accumulated damageis the sum of the fractions. Not all of these questions are answered in this appendix, The effect of the uncertainty about the rupture strength is but the method used to develop the answers should be clear evident in Table E-2. If the actual rupture strength ofthis from the following example. tube is in the lower part of the scatter band (near the mini- For this example, the expected operating conditions are as mum rupture strength), then 64 percent of the tube life has follows: COPYRIGHT American Petroleum Institute Licensed by Information Handling Services
  • 121. API STDx530 96 M 0732290 0563430 422 m CALCUlnTlON OF HEATER-TUBE THICKNESS IN PETROLEUM REFINERIES 115 Operating pressure = 620 pounds per square inch gauge For tubes that are not corroding, estimating the life is eas- (4.27 megapascals gauge). ier. The rupture life is calculated as above from the antici- pated stress and temperature. The estimated remaining life is Metal temperature = 1220°F (660°C). simply the fraction remaining times the rupture life. In these Corrosion rate = 0.013 inch per year cases, tables such as Tables E-3 and E-4 are not required. (0.33 millimeter per year). The examplegiven above describes a way to answer Ques- tion (a), posed at the beginning of this section: What is the From these values a table of future-life fractions can be estimated life for a specified set of operating conditions? developed as shown in Table E-3 for the minimum rupture Question (b), concerning the temperature limit that should be strength and in Table E-4 for the average rupture strength. As imposed for a specified pressure, corrosion rate, and mini- before, the average stress is the average of the stresses at the mum life, can be answered in the following way: The pres- beginning and endof each operating period. sure and corrosion rate can be used to calculate an average Since the tube in the example is corroding, the life estimation stress from which a Larson-Miller value can be found using should be calculated in steps. For this example,a I-year step was the curves i n Figures 4A-4S With this value and a rupture used. As can be seen from the two tables, the estimated life of life calculated by dividing the required life by the remaining this lube is between 1.5 and 4.5 years. If the rupture strength life fraction, the Larson-Miller parameter equation canbe were in the upper part of the scatter band (above the average solved for themaximum temperature. The other questions rupture strength), the estimated life would be even longer. can be answered in similar ways. Table E-%Future Life Fractions, Minimum Strength Minimum Larson-Miller Average Stress Value Minimum Thicknesss Time per Degrees Degrees Rupture Time Remaining (years) Inches Millimeters Square Inch Megapascals Fahrenheir Celsius Fraction Fraction (years) ~ ~ ~~ O O. 190 4.83 - - - - - - 0.36 1 0.177 4.50 10,896 74.99 32.85 18.25 4. I 0.24 0.12 1.5 0.171 4.34 11,497 3.179.19 32.66 18.14 0.16 -0.04 Table E-4-Future Life Fractions, Average Strength Minimum Larson-Miller Average Stress Value Minimum Thicknesss Time per Degrees Degrees Rupture Time Remaining ( ears) Y Inches Millimeters Square Inch Megapascals Fahrenheit Celsius Fraction Fraction (Years) O O. 190 4.83 - - - - - - 0.77 1 O. I77 4.50 10,896 74.99 33.60 18.66 0.68 11.4 0.09 2 O. 164 4.17 11,753 80.87 33.35 18.53 0.12 0.56 8.2 3 0.151 3.84 12,752 87.74 33.07 18.37 0.18 0.38 5.5 4 0.138 13,932 3.51 3.8 18.22 95.84 32.80 0.12 0.2635 0.132 4.5 2.6 18.07 14,940 32.53 102.76 0.19 -0.07 COPYRIGHT American Petroleum Institute Licensed by Information Handling Services
  • 122. ~~ A P I STD*530 76 m 0732270 0 5 6 1 4 1 1 369 M APPENDIX F-CALCULATION SHEETS Appendix F contains calculation sheets that are useful in aiding and documenting the calculation of minimum thickness and equivalent tube metal temperature. Individual sheets areprovided for calculations in customary or SI units. These calculation sheets may be reproduced.COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 123. CALCULATION OF HEATER-TUBE PETROLEUM THICKNESSIN REFINERIES 119 API STD 530 CALCULATION SHEET Customary Units Heater Plant Coil Elastic Rupture CALCULATIONOF MINIMUM THICKNESS Design Design Outside diameter, inches Do = D, = Design pressure, pounds per square inch gauge P, = P, = Maximum or equivalent metal temperature, degrees Fahrenheit T, = T, = Temperature allowance, degrees Fahrenheit TA = TA = Design metal temperature, degrees Fahrenheit Td = T, = Design life, hours - Ld = Allowable stress at Td, Figures 4A-4S, pounds per square inch S, = sr = Stress thickness, Equation2 or 4, inches t, = t, = Corrosion allowance, inches CA = CA = Corrosion fraction, Figure 1, n = B= f = Minimum thickness, Equation3 or 5, inches t, = t, = CALCULATIONOF EQUIVALENTTUBE METAL TEMPERATURE Duration of operating period, years L, = Metal temperature, startof run, degrees Fahrenheit Metal temperature, endof run, degrees Fahrenheit Teor = Temperature change during operating period, degrees Fahrenheit DT = Metal temperature, startot run, degrees Rankine T, = Thickness change during operating period, inches Dt = Assumed initial thickness, inches to = Corresponding initial stress, Equation 1, pounds per square inch S, = Material constant, Table3, pounds per squareinch A = Rupture exponent at Tsar, Figures 4A-4S no = Temperature fraction Figure 2, V = 2.9 N = 0.2 f r = Equivalent tube metal temperature, Equation6, degrees Fahrenheit Te =COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 124. 120 API STANDARD 530 API STD 530 CALCULATION SHEET SI Units Heater Plant Refinery Coil Material ASTM Spec. Rupture Elastic CALCULATION OF MINIMUM THICKNESS Design Design Outside diameter, millimeters D, = D, = Design pressure, megapascals gauge P, = P, = Maximum or equivalentmetal temperature, degrees Celsius T, = T, = Temperature allowance,degrees Celsius TA = TA = Design metal temperature, degrees Celsius Td = Td = Design life, hours - Ld = Allowable stress at Td,Figures 4A-4S, megapascals S, = S, = Stress thickness, Equation 2 or 4, millimeters t, = t, = Corrosion allowance, millimeters CA = CA = Corrosion fraction, Figure 1, n = B= - f = Minimum thickness, Equation 3 or 5, millimeters t, = t, = CALCULATION OF EQUIVALENT TUBE METAL TEMPERATURE Duration of operating period, years Lo = Metal temperature, startof run, degrees Celsius Cor = Metal temperature, endof run, degreesCelsius Teor = Temperature change during operating period, degreesCelsius DT = Metal temperature, startot run, degrees kelvin T, = Thickness change duringoperating period, millimeters Dt = Assumed initial thickness, millimeters to = Corresponding initial stress, Equation 1, megapascals S, = Material constant,Table 3, megapascals A = Rupture exponentat T,,,, Figures 4A-4S no = Temperature fraction Figure 2, V = 2.9 N = 0.2 f r = Equivalent tube metal temperature, Equation 6, degrees Celsius T, =COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 125. A P I STD*530 96 0732290 0561414 078 W APPENDIX G-BIBLIOGRAPHY 1. API Publication 941, Steels for Hydrogen Service at Ele- American Society for Testing and Materials,Philhdelphia, vated Temperatures and Pressures in Petroleum Refineries January 1970. andPetrochemical Plants, 4th ed., American Petroleum Institute, Washington, D.C.,April 1990. 11.Smith, G. V., Cr-Mo,Mn-Mo, and Mn-Mo-Ni Steels (Data Series 47), American Society for Testing and Materi- 2. Tucker, J. T., Coulter, E. E.,and Kouistra, L. F., “Effects of als, Philadelphia,November 1971. Wall Thickness on Stress-RuptureLife of Tubular Speci- mens,” Transactions of the American Society of Mechanical 12. Smith, G. V., 1/2Cr-11/2Mo, 1Cr-11/2M0, l’/4-1/2Mo-Si and Engineers, Series D: Journal of Basic Engineering, Vol. 82, Steels (Data Series 50), American Society for Testing and June 1960, pp. 465476. Materials, Philadelphia, September 1973. 3. Carlson, W. B., and Duval, D., “Rupture Data and Pipe 13. Smith,G. V., 3 to 9 Percent Chromium-Molybdenum Design Formulae.” Engineering, Vol. 193, June 22, 1962, pp. Steels (Data Series 58), American Society for Testing and 829-83 l . Materials, Philadelphia, October 1975. 4. Chitty, A., and Duval. D., “The Creep-Rupture Properties 14. Finnie, I., Design of Furnace Tubesfor the Creep Rupture of Tubes for High Temperature Steam Power Plant,” paper Range (Paper 62-WA-272), American Society of Mechanical presented at theJointInternationalConference on Creep, Engineers, New York, November 1962. New York and London, 1963. 15. Freeman, J. W., and Voorhees, H. R., Literature Survey 5. Yoshida, S., Tancha, C., Ichino, I., and Vematsu, K., on Creep Damage in Metals (Special Technical Publication “Creep and Creep-Rupture Properties of Type 3 16 Stainless No. 391), American Society for Testing and Materials, Phila- SteelCladding Tubes fortheExperimental Fast Breeder delphia, June 1965. Reactor JOYO,” Paper presented at the International Confer- ence on Creep and Fatigue in Elevated Temperature Applica- 16. Randall, P. N., “Cumulative Damage in Creep Rupture tions, Philadelphia, September 1973. Tests of a Carbon Steel,” Transactions the American Soci- of ety of Mechanical Engineers, Series D: Journal of Basic 6. ASME B31.3, ChemicalPlantandPetroleumRefinery Engineering, Vol. 84, June 1962, pp.239-242. Piping, American Society of Mechanical Engineers, New York. 17. Voorhees, H.R.,Freeman, J. W., and Herzog, J. A., “Trends and Implications of Data on Notched-Bar Creep- 7. ASME Boiler andPressureVessel Code,SectionVIII, Rupture,” Transactions of the American Societyof Mechani- “Rules forConstruction of Pressure Vessels,” Division2, cal Engineers, Series D: Journalof Basic Engineering, Vol. “Alternative Rules,” American Society of Mechanical Engi- 84, June 1962, pp. 207-213. neers, New York. 18. McAdams, W. H., Heat Transmission, 3rd ed., McGraw- 8. Smith, G. V., Wrought 304, 316, 321, and 347 Stainless Hill, New York, 1954. Steel (Data Series 5S2), American Society for Testing and Materials, Philadelphia, February 1969. 19. McEligot, D. M., Magee,P. M., and Leppart, G., “Effect of Large Temperature Gradients on Convective Heat Trans- 9. Smith, G . V., 2]/, Cr-IMO Steel (Data Series 6S2), American fer: The Downstream Region,” Transactions of the American Society for Testing and Materials, Philadelphia, March 1971, Society of Mechanical Engineers, SeriesC: Journal of Heat 10. Smith, G. V., Wrought Carbon Steel (Data Series 1 lSl), Transfel; Vol. 87, February 1965, pp. 67-76. 121COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 126. PG-0140&-10/96-1M (1E)COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services
  • 127. ~~~~~~ A P I STD*530 96 0732290 056141b 990 Additional copies available from Publications and Distribution: (202) 682-8375 Information aboutAPI Publications, Programs and Services available on the World WideWeb at: btp:/www.api.org American 1220 L Street, Northwest Petroleum Washington, D.C. 20005-4070 Order No. C53004 Institute 202-682-8000COPYRIGHT American Petroleum InstituteLicensed by Information Handling Services