This presentation is to show how to design heat exchanger from process simulation data to complete mechanical design by using two software HTRI and COMPRESS in seamless streamline Auto duping data.
2. Outline
Introduction
Why we need to use a systematic approach to design heat exchangers
What factors are needed to design a quality heat exchanger
How do we approach that goal
What are a Process engineers responsibilities
What are the Mechanical engineers responsibilities
What tools are available in-house for heat exchanger design
Heat Exchanger design codes
An example of step by step design for a heat exchanger
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Heat Exchanger Design training
3. INTRODUCTION
The objective of this training is to provide a concise review of the key issues involved in Heat Exchanger
design. At the start of the heat exchanger design, process and mechanical considerations are crucial. It
needs to be clearly understood what we want to achieve. The calculations in the software program
relies on careful considered input. Engineering judgment must be used to evaluate both thermal and
hydraulic the design results.
So what are the key parameters we should consider to produce a quality design?
The Data Sheet is the final product, all the hard work will be inputted here. When complete it is ready
to be issued to vendors, manufactures for quote.
Client often decide which Vendors to select.
Therefore, we want to produce a quality design to demonstrate we know how to design heat
exchangers.
How do we approach this goal?
Process Considerations
Mechanical Considerations
Construction Considerations
3
Heat Exchanger Design training
4. INTRODUCTION
Process Considerations
− How many heat exchangers are required?
− What duty?
− What type of utility (air, water, steam, hot oil) is required?
Mechanical Considerations
− What is the Lead Time and Cost?
Construction Considerations
Not covered here
4
Heat Exchanger Design training
5. Systematic Approach – the following steps are suggested
5
Ho do we approach to design a quality heat Exchanger?
6. Optimization possibilities
Is Optimization possible?
Pinch Technology is one of the optimize heat exchanger design methods. The results of the pinch
technology will targets for:
1. Calculate utility requirements
2. Estimate exchanger requirements
3. Overview of energy flows for entire process
4. Overall view of entire steam/power system
5. Potential energy saving in a process
6. Targets to aim for
• Quantity of exchangers (# shells, total area)
• Utility Capital cost targets
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Process Considerations
7. Data Extraction
To start the Pinch Analysis, we need
to extract the necessary thermal data
from process simulations as shown in
Figure 1.
Figures (a) & (b) on next page shows
an example represented by the two
process Flow sheets. We now apply
the pinch analysis principles to design
the heat exchanger.
* Pinch Technology (JGCA-1303-0132)
Example: Condenser Design
7
Fig. 1
Fig. 1 Work Steps Required*
9. Optimization possibilities
9
Example: Condenser design (cont.)
Table 1 shows the thermal extraction data for Pinch Analysis. Streams 1 & 2 are hot steams (heat sources).
Streams 3 & 4 are cold streams (heat sinks). Assume a minimum temperature difference of 10o C. The hot utility
is steam at 200o C and the cold utility is cooling water in the range 25 o C to 30 o C. Figures (a) & (b) represent a
graphical construction of the target for minimum energy consumption for the process.
Fig. 2 Construction of Composite CurvesTable 1
10. Example: Condenser design (cont.)
10
The minimum energy target for the process. The hot and cold composite curves are now overlapped on one another. Fig. (a), separating them by the
minimum temperature difference ∆Tmin = 10 C.
Fig. (b) shows the minimum hot utility (QHmin)
As you can see, using Pinch Analysis we are able to set targets for minimum energy consumption based on heat and material balance information prior
to heat exchanger design. This allows us to quickly identify any energy saving at an early stage.
For more details refer to JGCA-1303-0132 Pinch Technology
DETERMINING THE ENERGY TARGETS
11. The Pinch Principle
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The point where ∆Tmin is observed is
known as the “Pinch” and recognizing
its implications allow energy targets
to be realized in practice.
One above and one below the pinch,
as shown in Fig. (a). The system
above the pinch requires a heat input,
The system below the pinch rejects
heat, so is a net heat source. To
restore the heat balance, the hot
utility must be increased by the same
amount, that is, α units., therefore the
cold utility requirement also increases
by α units. In conclusion, the
consequence of a cross-pinch heat
transfer (α) is that both the hot and
cold utility will increase by the cross-
pinch duty (α).
DETERMINING THE ENERGY TARGETS
Example: Condenser design (cont.)
12. Systematic Approach – the following steps are suggested
There are two disciplines whose goal is to generate the HX datasheet. Process Engineer and Mechanical Engineer.
Process Responsibilities are:
◦ Selection of heat transfer models
◦ Define Fluid Composition for both shell side and tube side
◦ Define Operating Pressure and Temperature
◦ Define shell side and tube side allowable Pressure limits
◦ Define shell side and tube side velocity limits.
◦ Define Gravity or Density
◦ Define Specific Heat
◦ Define Viscosity, cp
◦ Define Fouling Factor for shell side and tube side
◦ Define Thermal Conductivity
◦ Define Latent Heat, (if phase change)
◦ Complete optimum thermal design
◦ Complete internal Process verification and checking and pass the Data Sheet to Mechanical
12
Ho do we approach to design a quality heat Exchanger?
13. Optimizing Heat Exchanger Process and Cost Effectiveness
Mechanical engineer shall use the Data Sheet from process and import the
data into COMPRESS. Then complete the mechanical design and complete
the mechanical sections of the Data Sheet.
Mechanical engineer responsibilities are:
1. Confirm the type of exchanger configuration.
2. Set upper and lower design limits on shell diameter
3. Set upper and lower design limits on tube length.
4. Specify both shell and tube side layout
5. Specify pitch, material, baffle cut, baffle spacing and clearances.
6. Prepare Material Requisition
7. Complete Technical Bid Evaluation on bids
Items 1 to 5 are covered in the following sections.
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Mechanical
14. Tools are available in-house for design the exchangers
There are two software programs in house
1) HTRI,
2) COMPRESS.
HTRI is best used for process thermal design and to produce TEMA
Datasheet.
COMPRESS is used to design the complete exchanger. Tubesheet(s), tubes,
expansion joint, shell, channels, flanges, head closures, nozzles, etc.
COMPRESS will generate shell side & tube side hydrotest conditions based
on the input design conditions.
There are four ways to create a heat exchanger in COMPRESS.
1. Start from “File” and select “New heat exchanger”.
2. Pressing “Ctrl T” on your keyboard
3. Import an HTRI designed file
4. To Start a File click on the heat exchanger icon found on the main menu
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Mechanical Design Software
15. Two methods are used in COMPRESS design.
a) TEMA
b) UHX methods.
When to use TEMA or UHX methods.
• When rating an existing exchanger built to TEMA.
• When supplying new equipment where TEMA has been specified in addition to UHX.
Regardless which option is selected, for new exchanger design. ASME is mandatory for tubesheet
design
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COMPRESS Heat Exchanger introduction
How does COMPRESS work
16. COMPRESS has a built in interface with HTRI.
COMPRESS can read and write HTRI’S Xist files
COMPRESS directly importing an existing HTRI file to complete the mechanical design
COMPRESS / HTRI interface enables shell and tube heat exchanger files design interchangeable
COMPRESS can analyze all components design conditions simultaneously
COMPRESS has built-in Design codes to check and evaluate components design conditions
• Such as ASME VIII UHX, TEMA, or both ASME VIII UHX & TEMA and more
16
How does COMPRESS work
18. Example by import an HTRI designed file
Before starting COMPRESS to design a heat exchanger, a few things are required. Open COMPRESS, on the lower right
corner, select the Mode, units, Div. and revision to set up the calculation Mode.
https://support.codeware.com/link/portal/9185/9191/Article/352/COMPRESS-Heat-Exchanger-Tutorial
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COMPRESS Heat Exchanger introduction
19. Step 1: Start the Heat Exchanger Wizard
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The following screenshots are example from COMPRESS
20. 20
This is the HTRI File Import Values. The color code indicate four results
The following screenshots are example from COMPRESS
21. Step 2: Edit an existing Heat Exchanger
21
The following screenshots are example from COMPRESS
In Fig. (b), α amount of heat is transferred from above the pinch, below the pinch. The system above the pinch, which was before in heat balance with QHmin, now loses α units of heat to the system below the pinch. Fig. 3.5(b) also shows γ amount of external cooling above the pinch and β amount of external heating below the pinch. The external cooling above the pinch of γ amount increases the hot utility demand by the same amount. Therefore on an overall basis both the hot and cold utilities are increased by γ amount. Similarly external heating below the pinch of β amount increases the overall hot and cold utility requirement by the same amount (i.e. β).
Once the pinch has been identified, it is possible to consider the process as two separate systems:
First Process Engineer to prepare the thermal rating part of datasheet them move to mechanical engineer to complete the datesheet.
All conditions are investigated simultaneously. The heat exchanger components may be evaluated using ASME UHX,, TEMA, or both ASME UHX & TEMA. The TEMA & ASME UHX option provides the tubesheet design thickness from both design codes allowing the nominal tubesheet thickness assignment to be based on either set of design rules. COMPRESS requires that the tube sheet thickness meets the ASME requirements.
The governing design condition, neglecting hydrotest conditions, specified in the heat exchanger wizard is automatically used for the vessel component ASME VIII-1 calculations (e.g. shell, channels, head closures, nozzles). It is not permissible to change the design parameters such as internal design pressure/temperature of individual components. These values must be changed through the heat exchanger wizard.
The TEMA & ASME VIII UHX option provides the tubesheet design thickness from both design codes allowing the nominal tubesheet thickness assignment to be based on either set of design rules. COMPRESS requires that the tube sheet thickness meets the ASME VIII requirements.
The governing design condition, neglecting hydrotest conditions, specified in the heat exchanger wizard is automatically used for the vessel component ASME VIII-1 calculations (e.g. shell, channels, head closures, nozzles). It is not permissible to change the design parThe TEMA standard is used to evaluate the tubesheet, tube, and shell. If this option is selected then further TEMA details will need to be specified in the TEMA option selection box.
ameters such as internal design pressure/temperature of individual components. These values must be changed through the heat exchanger wizard.
The heat exchanger components may be evaluated using TEMA, ASE UHX. or both.
In design mode, COMPRESS selects tube sheet thickness such that it meets the ASME requirements.
The governing design condition specified in the heat exchanger wizard is automatically used in the vessel component in ASME section 8 div. 1 calculations. The only way to change design parameters such as internal design pressure or temperature for heads, and shells is Through the heat exchanger dialogs provided by COMPRESS. This is done intentionally to preserve the integrity of the design.
First. Select te defaults you wish to use or create a new defaults file that may be used for future projects.
Depending on customer requirements. It may be better to create a new defaults file so that it may be used for future projects. Three options available. There are Fixed/Stationary Tube sheets. U-tube. And Floating Tube sheet.
The TEMA & ASME VIII UHX option provides the tubesheet design thickness from both design codes allowing the nominal tubesheet thickness assignment to be based on either set of design rules. COMPRESS requires that the tube sheet thickness meets the ASME VIII requirements.
The governing design condition, neglecting hydrotest conditions, specified in the heat exchanger wizard is automatically used for the vessel component ASME VIII-1 calculations (e.g. shell, channels, head closures, nozzles). It is not permissible to change the design parThe TEMA standard is used to evaluate the tubesheet, tube, and shell. If this option is selected then further TEMA details will need to be specified in the TEMA option selection box.
ameters such as internal design pressure/temperature of individual components. These values must be changed through the heat exchanger wizard.
The heat exchanger components may be evaluated using TEMA, ASE UHX. or both.
In design mode, COMPRESS selects tube sheet thickness such that it meets the ASME requirements.
The governing design condition specified in the heat exchanger wizard is automatically used in the vessel component in ASME section 8 div. 1 calculations. The only way to change design parameters such as internal design pressure or temperature for heads, and shells is Through the heat exchanger dialogs provided by COMPRESS. This is done intentionally to preserve the integrity of the design.
First. Select te defaults you wish to use or create a new defaults file that may be used for future projects.
Depending on customer requirements. It may be better to create a new defaults file so that it may be used for future projects. Three options available. There are Fixed/Stationary Tube sheets. U-tube. And Floating Tube sheet.
The heat exchanger components may be evaluated using TEMA, ASE UHX. or both.
In design mode, COMPRESS selects tube sheet thickness such that it meets the ASME requirements.
The governing design condition specified in the heat exchanger wizard is automatically used in the vessel component in ASME section 8 div. 1 calculations. The only way to change design parameters such as internal design pressure or temperature for heads, and shells is Through the heat exchanger dialogs provided by COMPRESS. This is done intentionally to preserve the integrity of the design.
First. Select te defaults you wish to use or create a new defaults file that may be used for future projects.
Depending on customer requirements. It may be better to create a new defaults file so that it may be used for future projects. Three options available. There are Fixed/Stationary Tube sheets. U-tube. And Floating Tube sheet.
These conditions typically include operating , start up, shut down, hydrotest, and upset conditions.
When no hydrotest conditions are specified then COMPRESS will generate shell side and tube side hydrotest conditions based on the input design conditions
The heat exchanger components may be evaluated using TEMA, ASE UHX. or both.
In design mode, COMPRESS selects tube sheet thickness such that it meets the ASME requirements.
The governing design condition specified in the heat exchanger wizard is automatically used in the vessel component in ASME section 8 div. 1 calculations. The only way to change design parameters such as internal design pressure or temperature for heads, and shells is Through the heat exchanger dialogs provided by COMPRESS. This is done intentionally to preserve the integrity of the design.
First. Select te defaults you wish to use or create a new defaults file that may be used for future projects.
Depending on customer requirements. It may be better to create a new defaults file so that it may be used for future projects. Three options available. There are Fixed/Stationary Tube sheets. U-tube. And Floating Tube sheet.
All conditions are investigated simultaneously. The heat exchanger components may be evaluated using ASME UHX,, TEMA, or both ASME UHX & TEMA. The TEMA & ASME UHX option provides the tubesheet design thickness from both design codes allowing the nominal tubesheet thickness assignment to be based on either set of design rules. COMPRESS requires that the tube sheet thickness meets the ASME requirements.
The governing design condition, neglecting hydrotest conditions, specified in the heat exchanger wizard is automatically used for the vessel component ASME VIII-1 calculations (e.g. shell, channels, head closures, nozzles). It is not permissible to change the design parameters such as internal design pressure/temperature of individual components. These values must be changed through the heat exchanger wizard.
If design a new HX . MSME UHX is mandatory. If you are re-rating and existing HX. Then option to select TEMA is available. The TEMA STANDARD IS USED TO EVALUATE THE BUBE SHEET, TUBE, AND SHELL. IF THIS OPTION IS selected than further TEMA details will need to be specified in the TEMA option selection box which will appear below.
The ASME option uses section 8 div. 1 UHX to evaluate the tube sheets. Tubes. Channel. And the shell.
For the ASME and TEMA option both methods are performed simultaneously allowing the designer to select either as the bases for design. When this option of active the larger required thickness of the two methods will be used.
Bothe TEMA and UHX are based on the same theory. TEMA makes certain simplifying assumptions. Where as UHX is more rigorous. Some notable differences are in the way UHX considers the tubesheet unperforated area to be a solid rim.. This detail is not included in TEMA. UHX considers the stiffening effect of the tube bundle and tubes on the tubesheet through the coefficient “F”. Also, UHX accounts for the edge displacements and rotations of the tube sheet and attached integral shell and/or channel. The question sometimes arises as to when to use both methods. One application is when rating an existing exchanger built to TEMA. Another is when supplying new equipment where TEMA has been specified in addition to UHX.
For more background information on UHX. Please refer to the UHX White paper found on the support page of Codeware’s website. Regardless which option is selected here, ass components other than the tubesheet are calculated per ASME section div. 1. Because we are design a new exchanger. ASME is mandatory for tub sheet design. If the ASME calculation method has been specified than shell bands are available. This option is only applicable when the shell is integrals with the tube sheet. This option is used to increase the thickness of the shell adjacent to the tube sheet.. Different materials of construction may be specified for the shell and shell bands. Shell bands may be used to optimize the tube sheet thickness even when the shell and channel stresses are not excessive.. Also, they may be used to decease the tubesheet thickness. The next option. Use Operating Temperatures for Load Cases 4-7 is for load case involving deferential expansion. The additional inputs will be needed at a later point if this option is checked
All conditions are investigated simultaneously. The heat exchanger components may be evaluated using ASME UHX,, TEMA, or both ASME UHX & TEMA. The TEMA & ASME UHX option provides the tubesheet design thickness from both design codes allowing the nominal tubesheet thickness assignment to be based on either set of design rules. COMPRESS requires that the tube sheet thickness meets the ASME requirements.
The governing design condition, neglecting hydrotest conditions, specified in the heat exchanger wizard is automatically used for the vessel component ASME VIII-1 calculations (e.g. shell, channels, head closures, nozzles). It is not permissible to change the design parameters such as internal design pressure/temperature of individual components. These values must be changed through the heat exchanger wizard.
If design a new HX . MSME UHX is mandatory. If you are re-rating and existing HX. Then option to select TEMA is available. The TEMA STANDARD IS USED TO EVALUATE THE BUBE SHEET, TUBE, AND SHELL. IF THIS OPTION IS selected than further TEMA details will need to be specified in the TEMA option selection box which will appear below.
The ASME option uses section 8 div. 1 UHX to evaluate the tube sheets. Tubes. Channel. And the shell.
For the ASME and TEMA option both methods are performed simultaneously allowing the designer to select either as the bases for design. When this option of active the larger required thickness of the two methods will be used.
Bothe TEMA and UHX are based on the same theory. TEMA makes certain simplifying assumptions. Where as UHX is more rigorous. Some notable differences are in the way UHX considers the tubesheet unperforated area to be a solid rim.. This detail is not included in TEMA. UHX considers the stiffening effect of the tube bundle and tubes on the tubesheet through the coefficient “F”. Also, UHX accounts for the edge displacements and rotations of the tube sheet and attached integral shell and/or channel. The question sometimes arises as to when to use both methods. One application is when rating an existing exchanger built to TEMA. Another is when supplying new equipment where TEMA has been specified in addition to UHX.
For more background information on UHX. Please refer to the UHX White paper found on the support page of Codeware’s website. Regardless which option is selected here, ass components other than the tubesheet are calculated per ASME section div. 1. Because we are design a new exchanger. ASME is mandatory for tub sheet design. If the ASME calculation method has been specified than shell bands are available. This option is only applicable when the shell is integrals with the tube sheet. This option is used to increase the thickness of the shell adjacent to the tube sheet.. Different materials of construction may be specified for the shell and shell bands. Shell bands may be used to optimize the tube sheet thickness even when the shell and channel stresses are not excessive.. Also, they may be used to decease the tubesheet thickness. The next option. Use Operating Temperatures for Load Cases 4-7 is for load case involving deferential expansion. The additional inputs will be needed at a later point if this option is checked
All conditions are investigated simultaneously. The heat exchanger components may be evaluated using ASME UHX,, TEMA, or both ASME UHX & TEMA. The TEMA & ASME UHX option provides the tubesheet design thickness from both design codes allowing the nominal tubesheet thickness assignment to be based on either set of design rules. COMPRESS requires that the tube sheet thickness meets the ASME requirements.
The governing design condition, neglecting hydrotest conditions, specified in the heat exchanger wizard is automatically used for the vessel component ASME VIII-1 calculations (e.g. shell, channels, head closures, nozzles). It is not permissible to change the design parameters such as internal design pressure/temperature of individual components. These values must be changed through the heat exchanger wizard.
If design a new HX . MSME UHX is mandatory. If you are re-rating and existing HX. Then option to select TEMA is available. The TEMA STANDARD IS USED TO EVALUATE THE BUBE SHEET, TUBE, AND SHELL. IF THIS OPTION IS selected than further TEMA details will need to be specified in the TEMA option selection box which will appear below.
The ASME option uses section 8 div. 1 UHX to evaluate the tube sheets. Tubes. Channel. And the shell.
For the ASME and TEMA option both methods are performed simultaneously allowing the designer to select either as the bases for design. When this option of active the larger required thickness of the two methods will be used.
Bothe TEMA and UHX are based on the same theory. TEMA makes certain simplifying assumptions. Where as UHX is more rigorous. Some notable differences are in the way UHX considers the tubesheet unperforated area to be a solid rim.. This detail is not included in TEMA. UHX considers the stiffening effect of the tube bundle and tubes on the tubesheet through the coefficient “F”. Also, UHX accounts for the edge displacements and rotations of the tube sheet and attached integral shell and/or channel. The question sometimes arises as to when to use both methods. One application is when rating an existing exchanger built to TEMA. Another is when supplying new equipment where TEMA has been specified in addition to UHX.
For more background information on UHX. Please refer to the UHX White paper found on the support page of Codeware’s website. Regardless which option is selected here, ass components other than the tubesheet are calculated per ASME section div. 1. Because we are design a new exchanger. ASME is mandatory for tub sheet design. If the ASME calculation method has been specified than shell bands are available. This option is only applicable when the shell is integrals with the tube sheet. This option is used to increase the thickness of the shell adjacent to the tube sheet.. Different materials of construction may be specified for the shell and shell bands. Shell bands may be used to optimize the tube sheet thickness even when the shell and channel stresses are not excessive.. Also, they may be used to decease the tubesheet thickness. The next option. Use Operating Temperatures for Load Cases 4-7 is for load case involving deferential expansion. The additional inputs will be needed at a later point if this option is checked
All conditions are investigated simultaneously. The heat exchanger components may be evaluated using ASME UHX,, TEMA, or both ASME UHX & TEMA. The TEMA & ASME UHX option provides the tubesheet design thickness from both design codes allowing the nominal tubesheet thickness assignment to be based on either set of design rules. COMPRESS requires that the tube sheet thickness meets the ASME requirements.
The governing design condition, neglecting hydrotest conditions, specified in the heat exchanger wizard is automatically used for the vessel component ASME VIII-1 calculations (e.g. shell, channels, head closures, nozzles). It is not permissible to change the design parameters such as internal design pressure/temperature of individual components. These values must be changed through the heat exchanger wizard.
If design a new HX . MSME UHX is mandatory. If you are re-rating and existing HX. Then option to select TEMA is available. The TEMA STANDARD IS USED TO EVALUATE THE BUBE SHEET, TUBE, AND SHELL. IF THIS OPTION IS selected than further TEMA details will need to be specified in the TEMA option selection box which will appear below.
The ASME option uses section 8 div. 1 UHX to evaluate the tube sheets. Tubes. Channel. And the shell.
For the ASME and TEMA option both methods are performed simultaneously allowing the designer to select either as the bases for design. When this option of active the larger required thickness of the two methods will be used.
Bothe TEMA and UHX are based on the same theory. TEMA makes certain simplifying assumptions. Where as UHX is more rigorous. Some notable differences are in the way UHX considers the tubesheet unperforated area to be a solid rim.. This detail is not included in TEMA. UHX considers the stiffening effect of the tube bundle and tubes on the tubesheet through the coefficient “F”. Also, UHX accounts for the edge displacements and rotations of the tube sheet and attached integral shell and/or channel. The question sometimes arises as to when to use both methods. One application is when rating an existing exchanger built to TEMA. Another is when supplying new equipment where TEMA has been specified in addition to UHX.
For more background information on UHX. Please refer to the UHX White paper found on the support page of Codeware’s website. Regardless which option is selected here, ass components other than the tubesheet are calculated per ASME section div. 1. Because we are design a new exchanger. ASME is mandatory for tub sheet design. If the ASME calculation method has been specified than shell bands are available. This option is only applicable when the shell is integrals with the tube sheet. This option is used to increase the thickness of the shell adjacent to the tube sheet.. Different materials of construction may be specified for the shell and shell bands. Shell bands may be used to optimize the tube sheet thickness even when the shell and channel stresses are not excessive.. Also, they may be used to decease the tubesheet thickness. The next option. Use Operating Temperatures for Load Cases 4-7 is for load case involving deferential expansion. The additional inputs will be needed at a later point if this option is checked
All conditions are investigated simultaneously. The heat exchanger components may be evaluated using ASME UHX,, TEMA, or both ASME UHX & TEMA. The TEMA & ASME UHX option provides the tubesheet design thickness from both design codes allowing the nominal tubesheet thickness assignment to be based on either set of design rules. COMPRESS requires that the tube sheet thickness meets the ASME requirements.
The governing design condition, neglecting hydrotest conditions, specified in the heat exchanger wizard is automatically used for the vessel component ASME VIII-1 calculations (e.g. shell, channels, head closures, nozzles). It is not permissible to change the design parameters such as internal design pressure/temperature of individual components. These values must be changed through the heat exchanger wizard.
If design a new HX . MSME UHX is mandatory. If you are re-rating and existing HX. Then option to select TEMA is available. The TEMA STANDARD IS USED TO EVALUATE THE BUBE SHEET, TUBE, AND SHELL. IF THIS OPTION IS selected than further TEMA details will need to be specified in the TEMA option selection box which will appear below.
The ASME option uses section 8 div. 1 UHX to evaluate the tube sheets. Tubes. Channel. And the shell.
For the ASME and TEMA option both methods are performed simultaneously allowing the designer to select either as the bases for design. When this option of active the larger required thickness of the two methods will be used.
Bothe TEMA and UHX are based on the same theory. TEMA makes certain simplifying assumptions. Where as UHX is more rigorous. Some notable differences are in the way UHX considers the tubesheet unperforated area to be a solid rim.. This detail is not included in TEMA. UHX considers the stiffening effect of the tube bundle and tubes on the tubesheet through the coefficient “F”. Also, UHX accounts for the edge displacements and rotations of the tube sheet and attached integral shell and/or channel. The question sometimes arises as to when to use both methods. One application is when rating an existing exchanger built to TEMA. Another is when supplying new equipment where TEMA has been specified in addition to UHX.
For more background information on UHX. Please refer to the UHX White paper found on the support page of Codeware’s website. Regardless which option is selected here, ass components other than the tubesheet are calculated per ASME section div. 1. Because we are design a new exchanger. ASME is mandatory for tub sheet design. If the ASME calculation method has been specified than shell bands are available. This option is only applicable when the shell is integrals with the tube sheet. This option is used to increase the thickness of the shell adjacent to the tube sheet.. Different materials of construction may be specified for the shell and shell bands. Shell bands may be used to optimize the tube sheet thickness even when the shell and channel stresses are not excessive.. Also, they may be used to decease the tubesheet thickness. The next option. Use Operating Temperatures for Load Cases 4-7 is for load case involving deferential expansion. The additional inputs will be needed at a later point if this option is checked
All conditions are investigated simultaneously. The heat exchanger components may be evaluated using ASME UHX,, TEMA, or both ASME UHX & TEMA. The TEMA & ASME UHX option provides the tubesheet design thickness from both design codes allowing the nominal tubesheet thickness assignment to be based on either set of design rules. COMPRESS requires that the tube sheet thickness meets the ASME requirements.
The governing design condition, neglecting hydrotest conditions, specified in the heat exchanger wizard is automatically used for the vessel component ASME VIII-1 calculations (e.g. shell, channels, head closures, nozzles). It is not permissible to change the design parameters such as internal design pressure/temperature of individual components. These values must be changed through the heat exchanger wizard.
If design a new HX . MSME UHX is mandatory. If you are re-rating and existing HX. Then option to select TEMA is available. The TEMA STANDARD IS USED TO EVALUATE THE BUBE SHEET, TUBE, AND SHELL. IF THIS OPTION IS selected than further TEMA details will need to be specified in the TEMA option selection box which will appear below.
The ASME option uses section 8 div. 1 UHX to evaluate the tube sheets. Tubes. Channel. And the shell.
For the ASME and TEMA option both methods are performed simultaneously allowing the designer to select either as the bases for design. When this option of active the larger required thickness of the two methods will be used.
Bothe TEMA and UHX are based on the same theory. TEMA makes certain simplifying assumptions. Where as UHX is more rigorous. Some notable differences are in the way UHX considers the tubesheet unperforated area to be a solid rim.. This detail is not included in TEMA. UHX considers the stiffening effect of the tube bundle and tubes on the tubesheet through the coefficient “F”. Also, UHX accounts for the edge displacements and rotations of the tube sheet and attached integral shell and/or channel. The question sometimes arises as to when to use both methods. One application is when rating an existing exchanger built to TEMA. Another is when supplying new equipment where TEMA has been specified in addition to UHX.
For more background information on UHX. Please refer to the UHX White paper found on the support page of Codeware’s website. Regardless which option is selected here, ass components other than the tubesheet are calculated per ASME section div. 1. Because we are design a new exchanger. ASME is mandatory for tub sheet design. If the ASME calculation method has been specified than shell bands are available. This option is only applicable when the shell is integrals with the tube sheet. This option is used to increase the thickness of the shell adjacent to the tube sheet.. Different materials of construction may be specified for the shell and shell bands. Shell bands may be used to optimize the tube sheet thickness even when the shell and channel stresses are not excessive.. Also, they may be used to decease the tubesheet thickness. The next option. Use Operating Temperatures for Load Cases 4-7 is for load case involving deferential expansion. The additional inputs will be needed at a later point if this option is checked