The document discusses the design of absorption and stripping columns, including the equipment used for absorption and stripping of dilute mixtures in trayed towers and packed columns. It covers the graphical equilibrium-stage and algebraic methods for determining the number of stages in trayed towers, as well as the rate-based method for packed columns. The document also addresses factors to consider in the general design of absorbers and strippers such as the composition and flow rates of incoming streams, desired recovery levels, operating conditions, and minimum liquid rates.
Chato lox tank helium removal for propellant scavenging presentation 2009David Chato
System studies have shown a significant advantage to reusing the hydrogen and oxygen left in
these tanks after landing on the Moon in fuel cells to generate power and water for surface
systems. However in the current lander concepts, the helium used to pressurize the oxygen tank
can substantially degrade fuel cell power and water output by covering the reacting surface with
inert gas. This presentation documents an experimental investigation of methods to remove the
helium pressurant while minimizing the amount of the oxygen lost. This investigation
demonstrated that significant quantities of Helium (>90% mole fraction) remain in the tank after
draining. Although a single vent cycle reduced the helium quantity, large amounts of helium
remained. Cyclic venting appeared to be more effective. Three vent cycles were sufficient to
reduce the helium to small (<0.2%) quantities. Two vent cycles may be sufficient since once the
tank has been brought up to pressure after the second vent cycle the helium concentration has
been reduced to the less than 0.2% level. The re-pressurization process seemed to contribute to
diluting helium. This is as expected since in order to raise the pressure liquid oxygen must be
evaporated. Estimated liquid oxygen loss is on the order of 82 pounds (assuming the third vent
cycle is not required).
Chato lox tank helium removal for propellant scavenging presentation 2009David Chato
System studies have shown a significant advantage to reusing the hydrogen and oxygen left in
these tanks after landing on the Moon in fuel cells to generate power and water for surface
systems. However in the current lander concepts, the helium used to pressurize the oxygen tank
can substantially degrade fuel cell power and water output by covering the reacting surface with
inert gas. This presentation documents an experimental investigation of methods to remove the
helium pressurant while minimizing the amount of the oxygen lost. This investigation
demonstrated that significant quantities of Helium (>90% mole fraction) remain in the tank after
draining. Although a single vent cycle reduced the helium quantity, large amounts of helium
remained. Cyclic venting appeared to be more effective. Three vent cycles were sufficient to
reduce the helium to small (<0.2%) quantities. Two vent cycles may be sufficient since once the
tank has been brought up to pressure after the second vent cycle the helium concentration has
been reduced to the less than 0.2% level. The re-pressurization process seemed to contribute to
diluting helium. This is as expected since in order to raise the pressure liquid oxygen must be
evaporated. Estimated liquid oxygen loss is on the order of 82 pounds (assuming the third vent
cycle is not required).
An artificial intelligence based improved classification of two-phase flow patte...ISA Interchange
Flow pattern recognition is necessary to select design equations for finding operating details of the process and to perform computational simulations. Visual image processing can be used to automate the interpretation of patterns in two-phase flow. In this paper, an attempt has been made to improve the classification accuracy of the flow pattern of gas/ liquid two- phase flow using fuzzy logic and Support Vector Machine (SVM) with Principal Component Analysis (PCA). The videos of six different types of flow patterns namely, annular flow, bubble flow, churn flow, plug flow, slug flow and stratified flow are re- corded for a period and converted to 2D images for processing. The textural and shape features extracted using image processing are applied as inputs to various classification schemes namely fuzzy logic, SVM and SVM with PCA in order to identify the type of flow pattern. The results obtained are compared and it is observed that SVM with features reduced using PCA gives the better classification accuracy and computationally less intensive than other two existing schemes. This study results cover industrial application needs including oil and gas and any other gas-liquid two-phase flows.
Application of Foamy Mineral Oil Flow under Solution Gas Drive toa Field Crud...theijes
Heavy oil Flow in the form of foamy oil under solution gas drive is widely observed in many Canadian reservoirs. Despite the importance of such phenomenon, complexity involved in foamy oil flow in porous media is not well understood. Series of numerical simulations were performed to model experiments that were carried out in a two meter long Sand pack to investigate the conditions required to increase oil production under solution gas drive mechanism. Through these experiments the solution gas drive performance at different depletion rates were analyzed. Creation of foamy heavy oil is thought to be responsible for higher recovery factors compared to what is expected from the conventional solution gas drive theory. However, the complex nature of foamy oil and different transport parameters are yet to be understood.The results of this study can be used to numerically model foamy-oil mechanism in heavy oil reservoirs. Furthermore, the results can be applied for reservoir production optimization as well as management. A new model has been developed using commercial numerical simulator, computer modeling group, (CMG-STARSTM). By using the experimental data, different experimental production histories have been matched. Effect of different parameters such as fluid and reservoir properties and depletion rate on foamy oil recovery have been evaluated. The results reveal that despite many difficulties, foamy oil flow through porous media can be numerically modeled. However these models will strongly depend on a good understanding of many different parameters including rock-fluid interaction, as well as the depletion rates. Given the complex nature of such systems, this numerical model can be used to simulate and predict the oil and gas production from heavy oil reservoirs under foamy oil conditions
Gas lift system is optimized by use of PVT data combined with fluid and multiphase flow correlations. The aim of project is to develop a generalized program that eliminate the use of synthetic Gradient curves and sensitivity of system with respect to each parameter can be analyzed easily. The project is mainly based on two pressure gradient models; one is single phase flow of compressible fluids (gas) and second is multi-phase correlation developed by Hagedorn and Brown3 including Griffith correction4 of bubble flow particularly for vertical wellbores. Different but appropriate PVT correlations are adopted to suit the condition. The project is divided into two parts, first is developing single Gas lift diagram and second is multiple Gas lift diagrams which facilitate to derive Equilibrium curve, usually use to have idea of unloading valves at different depths with varying flowrates
Oil & Gas Pipelines are often subjected to an operation called ‘Pigging’ for maintenance purposes (For e.g., cleaning the pipeline of accumulated liquids or waxes). A pig is launched from a pig launcher that scrapes out the remnant contents of the pipeline into a vessel known as a ‘Slug catcher’. The term slug catcher is used since pigging operations produces a Slug flow regime characterized by the alternating columns of liquids & gases. Slug catcher’s are popularly of two types – Horizontal Vessel Type & Finger Type Slug catcher. However irrespective of the type used, the determination of the slug catcher volume becomes the primary step before choosing the slug catcher type.
Study of Velocity and Pressure Distribution Characteristics Inside Of Catalyt...ijceronline
International Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
Chato low gravity cryogenic liquid acquisition for space exploration 2014David Chato
NASA is currently developing propulsion system concepts for human exploration. These propulsion concepts will require the vapor free acquisition and delivery of the cryogenic propellants stored in the propulsion tanks during periods of microgravity to the exploration vehicles engines. Propellant management devices (PMD’s), such as screen channel capillary liquid acquisition devices (LAD’s), vanes and sponges currently are used for earth storable propellants in the Space Shuttle Orbiter and other spacecraft propulsion systems, but only very limited propellant management capability currently exists for cryogenic propellants. NASA is developing PMD technology as a part of their cryogenic propellant storage and transfer (CPST) project. System concept studies are looking at the key factors that dictate the size and shape of PMD devices and established screen channel LADs as an important component of PMD design. Normal gravity experiments and modeling are studying the behavior of the flow in LAD channel assemblies (as opposed to only prior testing of screen samples ) at the flow rates representative of actual engine service. Recently testing of LAD channels in liquid Hydrogen was completed. Three different types of test were conducted: Measurement of the pressure drop for flow through a one inch diameter screen sample; Measurement of the pressure drop in a horizontally-mounted rectangular LAD channel assembly at flow rates representative of a main engine firing; and determination of bubble breakthrough for flow into a partially-immersed vertically-mounted LAD channel. This presentation will present an overview of low gravity cryogenic liquid acquisition strategies, review the findings of this recent test series, and discuss the implications of the testing and studies to exploration mission concepts.
A Novel Technique to Solve Mathematical Model of Pressure Swing Adsorption Sy...ijsrd.com
The mathematical modeling of a Pressure Swing Adsorption (PSA) system is discussed in detail for the Skarstrom cycle of two-bed process. The system is used to get pure oxygen product from the air with the use of zeolite 13X as an adsorbent. There are complex partial differential equations (pdes) which may not solve by analytical methods. There is no provision for solving it in any other software other than Matlab. All the equations are rearranged and written into dimensionless quantities, to make it easier. It is a novel technique of solving these complex PDEs. After that we have converted these PDEs into ODEs (Ordinary Differential Equations) by using OCFE (Orthogonal Collocation on Finite Elements) method. Now, these ODEs can be solved using different solvers like ode23, ode45, ode113, ode15s, ode23s, ode23t, ode23tb. The results obtained by this model will be compared to real industrial data.
An artificial intelligence based improved classification of two-phase flow patte...ISA Interchange
Flow pattern recognition is necessary to select design equations for finding operating details of the process and to perform computational simulations. Visual image processing can be used to automate the interpretation of patterns in two-phase flow. In this paper, an attempt has been made to improve the classification accuracy of the flow pattern of gas/ liquid two- phase flow using fuzzy logic and Support Vector Machine (SVM) with Principal Component Analysis (PCA). The videos of six different types of flow patterns namely, annular flow, bubble flow, churn flow, plug flow, slug flow and stratified flow are re- corded for a period and converted to 2D images for processing. The textural and shape features extracted using image processing are applied as inputs to various classification schemes namely fuzzy logic, SVM and SVM with PCA in order to identify the type of flow pattern. The results obtained are compared and it is observed that SVM with features reduced using PCA gives the better classification accuracy and computationally less intensive than other two existing schemes. This study results cover industrial application needs including oil and gas and any other gas-liquid two-phase flows.
Application of Foamy Mineral Oil Flow under Solution Gas Drive toa Field Crud...theijes
Heavy oil Flow in the form of foamy oil under solution gas drive is widely observed in many Canadian reservoirs. Despite the importance of such phenomenon, complexity involved in foamy oil flow in porous media is not well understood. Series of numerical simulations were performed to model experiments that were carried out in a two meter long Sand pack to investigate the conditions required to increase oil production under solution gas drive mechanism. Through these experiments the solution gas drive performance at different depletion rates were analyzed. Creation of foamy heavy oil is thought to be responsible for higher recovery factors compared to what is expected from the conventional solution gas drive theory. However, the complex nature of foamy oil and different transport parameters are yet to be understood.The results of this study can be used to numerically model foamy-oil mechanism in heavy oil reservoirs. Furthermore, the results can be applied for reservoir production optimization as well as management. A new model has been developed using commercial numerical simulator, computer modeling group, (CMG-STARSTM). By using the experimental data, different experimental production histories have been matched. Effect of different parameters such as fluid and reservoir properties and depletion rate on foamy oil recovery have been evaluated. The results reveal that despite many difficulties, foamy oil flow through porous media can be numerically modeled. However these models will strongly depend on a good understanding of many different parameters including rock-fluid interaction, as well as the depletion rates. Given the complex nature of such systems, this numerical model can be used to simulate and predict the oil and gas production from heavy oil reservoirs under foamy oil conditions
Gas lift system is optimized by use of PVT data combined with fluid and multiphase flow correlations. The aim of project is to develop a generalized program that eliminate the use of synthetic Gradient curves and sensitivity of system with respect to each parameter can be analyzed easily. The project is mainly based on two pressure gradient models; one is single phase flow of compressible fluids (gas) and second is multi-phase correlation developed by Hagedorn and Brown3 including Griffith correction4 of bubble flow particularly for vertical wellbores. Different but appropriate PVT correlations are adopted to suit the condition. The project is divided into two parts, first is developing single Gas lift diagram and second is multiple Gas lift diagrams which facilitate to derive Equilibrium curve, usually use to have idea of unloading valves at different depths with varying flowrates
Oil & Gas Pipelines are often subjected to an operation called ‘Pigging’ for maintenance purposes (For e.g., cleaning the pipeline of accumulated liquids or waxes). A pig is launched from a pig launcher that scrapes out the remnant contents of the pipeline into a vessel known as a ‘Slug catcher’. The term slug catcher is used since pigging operations produces a Slug flow regime characterized by the alternating columns of liquids & gases. Slug catcher’s are popularly of two types – Horizontal Vessel Type & Finger Type Slug catcher. However irrespective of the type used, the determination of the slug catcher volume becomes the primary step before choosing the slug catcher type.
Study of Velocity and Pressure Distribution Characteristics Inside Of Catalyt...ijceronline
International Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
Chato low gravity cryogenic liquid acquisition for space exploration 2014David Chato
NASA is currently developing propulsion system concepts for human exploration. These propulsion concepts will require the vapor free acquisition and delivery of the cryogenic propellants stored in the propulsion tanks during periods of microgravity to the exploration vehicles engines. Propellant management devices (PMD’s), such as screen channel capillary liquid acquisition devices (LAD’s), vanes and sponges currently are used for earth storable propellants in the Space Shuttle Orbiter and other spacecraft propulsion systems, but only very limited propellant management capability currently exists for cryogenic propellants. NASA is developing PMD technology as a part of their cryogenic propellant storage and transfer (CPST) project. System concept studies are looking at the key factors that dictate the size and shape of PMD devices and established screen channel LADs as an important component of PMD design. Normal gravity experiments and modeling are studying the behavior of the flow in LAD channel assemblies (as opposed to only prior testing of screen samples ) at the flow rates representative of actual engine service. Recently testing of LAD channels in liquid Hydrogen was completed. Three different types of test were conducted: Measurement of the pressure drop for flow through a one inch diameter screen sample; Measurement of the pressure drop in a horizontally-mounted rectangular LAD channel assembly at flow rates representative of a main engine firing; and determination of bubble breakthrough for flow into a partially-immersed vertically-mounted LAD channel. This presentation will present an overview of low gravity cryogenic liquid acquisition strategies, review the findings of this recent test series, and discuss the implications of the testing and studies to exploration mission concepts.
A Novel Technique to Solve Mathematical Model of Pressure Swing Adsorption Sy...ijsrd.com
The mathematical modeling of a Pressure Swing Adsorption (PSA) system is discussed in detail for the Skarstrom cycle of two-bed process. The system is used to get pure oxygen product from the air with the use of zeolite 13X as an adsorbent. There are complex partial differential equations (pdes) which may not solve by analytical methods. There is no provision for solving it in any other software other than Matlab. All the equations are rearranged and written into dimensionless quantities, to make it easier. It is a novel technique of solving these complex PDEs. After that we have converted these PDEs into ODEs (Ordinary Differential Equations) by using OCFE (Orthogonal Collocation on Finite Elements) method. Now, these ODEs can be solved using different solvers like ode23, ode45, ode113, ode15s, ode23s, ode23t, ode23tb. The results obtained by this model will be compared to real industrial data.
Immunizing Image Classifiers Against Localized Adversary Attacksgerogepatton
This paper addresses the vulnerability of deep learning models, particularly convolutional neural networks
(CNN)s, to adversarial attacks and presents a proactive training technique designed to counter them. We
introduce a novel volumization algorithm, which transforms 2D images into 3D volumetric representations.
When combined with 3D convolution and deep curriculum learning optimization (CLO), itsignificantly improves
the immunity of models against localized universal attacks by up to 40%. We evaluate our proposed approach
using contemporary CNN architectures and the modified Canadian Institute for Advanced Research (CIFAR-10
and CIFAR-100) and ImageNet Large Scale Visual Recognition Challenge (ILSVRC12) datasets, showcasing
accuracy improvements over previous techniques. The results indicate that the combination of the volumetric
input and curriculum learning holds significant promise for mitigating adversarial attacks without necessitating
adversary training.
Cosmetic shop management system project report.pdfKamal Acharya
Buying new cosmetic products is difficult. It can even be scary for those who have sensitive skin and are prone to skin trouble. The information needed to alleviate this problem is on the back of each product, but it's thought to interpret those ingredient lists unless you have a background in chemistry.
Instead of buying and hoping for the best, we can use data science to help us predict which products may be good fits for us. It includes various function programs to do the above mentioned tasks.
Data file handling has been effectively used in the program.
The automated cosmetic shop management system should deal with the automation of general workflow and administration process of the shop. The main processes of the system focus on customer's request where the system is able to search the most appropriate products and deliver it to the customers. It should help the employees to quickly identify the list of cosmetic product that have reached the minimum quantity and also keep a track of expired date for each cosmetic product. It should help the employees to find the rack number in which the product is placed.It is also Faster and more efficient way.
About
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Technical Specifications
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
Key Features
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface
• Compatible with MAFI CCR system
• Copatiable with IDM8000 CCR
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
Application
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Sachpazis:Terzaghi Bearing Capacity Estimation in simple terms with Calculati...Dr.Costas Sachpazis
Terzaghi's soil bearing capacity theory, developed by Karl Terzaghi, is a fundamental principle in geotechnical engineering used to determine the bearing capacity of shallow foundations. This theory provides a method to calculate the ultimate bearing capacity of soil, which is the maximum load per unit area that the soil can support without undergoing shear failure. The Calculation HTML Code included.
Student information management system project report ii.pdfKamal Acharya
Our project explains about the student management. This project mainly explains the various actions related to student details. This project shows some ease in adding, editing and deleting the student details. It also provides a less time consuming process for viewing, adding, editing and deleting the marks of the students.
CFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptxR&R Consult
CFD analysis is incredibly effective at solving mysteries and improving the performance of complex systems!
Here's a great example: At a large natural gas-fired power plant, where they use waste heat to generate steam and energy, they were puzzled that their boiler wasn't producing as much steam as expected.
R&R and Tetra Engineering Group Inc. were asked to solve the issue with reduced steam production.
An inspection had shown that a significant amount of hot flue gas was bypassing the boiler tubes, where the heat was supposed to be transferred.
R&R Consult conducted a CFD analysis, which revealed that 6.3% of the flue gas was bypassing the boiler tubes without transferring heat. The analysis also showed that the flue gas was instead being directed along the sides of the boiler and between the modules that were supposed to capture the heat. This was the cause of the reduced performance.
Based on our results, Tetra Engineering installed covering plates to reduce the bypass flow. This improved the boiler's performance and increased electricity production.
It is always satisfying when we can help solve complex challenges like this. Do your systems also need a check-up or optimization? Give us a call!
Work done in cooperation with James Malloy and David Moelling from Tetra Engineering.
More examples of our work https://www.r-r-consult.dk/en/cases-en/
Saudi Arabia stands as a titan in the global energy landscape, renowned for its abundant oil and gas resources. It's the largest exporter of petroleum and holds some of the world's most significant reserves. Let's delve into the top 10 oil and gas projects shaping Saudi Arabia's energy future in 2024.
Water scarcity is the lack of fresh water resources to meet the standard water demand. There are two type of water scarcity. One is physical. The other is economic water scarcity.
2. Key and Difficult Points:
Key Points
Equipment of Absorption and Stripping
Graphical Equilibrium-Stage Method for Trayed Towers
Algebraic Method for Trayed Towers
Rate-Based Method for Packed Towers
Difficult Points
Algebraic Method for Trayed Towers
Rate-Based Method for Packed Towers
Purpose and Requirements:
Know Equipment of Absorption and Stripping
Learn to Design a trayed Tower and a packed Tower
3. Outline
6.1 EQUIPMENT
6.2 GENERAL DESIGN CONSIDERATIONS
6.3 GRAPHICAL EQUILIBRIUM-STAGE METHOD FOR TRAYED
TOWERS
6.4 ALGEBRAIC METHOD FOR DETERMINING THE NUMBER OF
EQUILIBRIUM STAGES
6.5 STAGE EFFICIENCY
6.6 TRAY CAPACITY, PRESSURE DROP, AND MASS
TRANSFER
6.7 RATE-BASED METHOD FOR PACKED COLUMNS
6.8 PACKED COLUMN EFFICIENCY, CAPACITY, AND
PRESSURE DROP
6.9 CONCENTRATED SOLUTIONS IN PACKED COLUMNS
4. Absorption
(Gas Absorption/Gas Scrubbing/Gas Washing 吸收 )
Gas Mixture (Solutes or Absorbate)
Liquid (Solvent or Absorbent)
Separate Gas Mixtures
Remove Impurities, Contaminants, Pollutants, or
Catalyst Poisons from a Gas(H2S/Natural Gas)
Recover Valuable Chemicals
5. Figure 6.1 Typical Absorption Process
Chemical Absorption
(Reactive Absorption)
Physical Absorption
6. Absorption Factor
(A 吸收因子 )
A = L/KV
Component A = L/KV K-value
Water 1.7 0.031
Acetone 1.38 2.0
Oxygen 0.00006 45,000
Nitrogen 0.00003 90,000
Argon 0.00008 35,000
•Larger the value of A , Fewer the number of stages required
•1.25 to 2.0 , 1.4 being a frequently recommended value
7. Stripping
(Desorption 解吸 )
Stripping
Distillation
Stripping Factor
(S 解吸因子 )
S = 1/ A= KV/L High temperature
Low pressure is desirable
Optimum stripping factor : 1.4.
8. 6.1 EQUIPMENT
Figure 6.2 Industrial Equipment for Absorption and Stripping
trayed tower packed column
spray towerbubble column
centrifugal contactor
9. Figure 6.3 Details of a contacting tray in a trayed tower
Trayed Tower
(Plate Clolumns 板式塔 )
10. Figure 6.4 Three types of tray openings for
passage of vapor up into liquid
(d) Tray with valve caps
(b) valve cap (c) bubble cap(a) perforation
11. Figure 6.5 Possible vapor-liquid flow regimes for a contacting tray
(a) Spray(b) Froth(c) Emulsion(d) Bubble(e)Cellular Foam
Froth Liquid carries no vapor bubbles
to the tray below
Vapor carries no liquid droplets
to the tray above
No weeping of liquid through the
openings of the tray
Equilibrium between the exiting
vapor and liquid phases
is approached on each tray.
13. Figure 6.7 Typical materials used in a packed column
Packing Materails
(a) Random Packing
Materials
(b) Structured Packing
Materials
•More surface area for mass transfer
•Higher flow capacity
•Lower pressure drop
•Expensive
•Far less pressure drop
•Higher efficiency and capacity
14. 6.2 ABSORBER/STRIPPER DESIGN
6.2.1 General Design Considerations
6.2.2 Trayed Towers
6.2.2.1 Graphical Equilibrium-Stage
6.2.2.2 Algebraic Method for Determining
the Number of Equilibrium
6.2.2.3 Stage Efficiency
6.2.3 Packed Columns
6.2.3.1 Rate-based Method
6.2.3.2 Packed Column Efficiency, Capacity,
and Pressure Drop
15. 6.2.1 General Design Considerations
1. Entering gas (liquid) flow rate, composition,
temperature, and pressure
2. Desired degree of recovery of one or more solutes
3. Choice of absorbent (stripping agent)
4. Operating pressure and temperature, and allowable
gas pressure drop
5. Minimum absorbent (stripping agent) flow rate and
actual absorbent (stripping agent) flow rate as a
multiple of the minimum rate needed to make the
separation
Design or analysis of an absorber (or stripper) requires
consideration of a number of factors, including:
6. Number of equilibrium stages
7. Heat effects and need for cooling (heating)
8. Type of absorber (stripper) equipment
9. Height of absorber (stripper)
10. Diameter of absorber (stripper)
16. SUMMARY
1. A liquid can be used to selectively absorb one or more components from a
gas mixture. A gas can be used to selectively desorb or strip one or more
components from a liquid mixture.
2. The fraction of a component that can be absorbed or stripped in a
countercurrent cascade depends on the number of equilibrium stages and the
absorption facto: A = L/KV, or the stripping factor, S = KV/L, respectively.
3. Absorption and stripping are most commonly conducted in trayed towers
equipped with sieve or valve trays, or in towers packed with random or
structured packings.
4. Absorbers are most effectively operated at high pressure and low
temperature. The reverse is true for stripping. However, high costs of gas
compression, refrigeration and vacuum often preclude operation at the most
thermodynamically favorable conditions.
5. For a given gas flow rate and composition, a desired degree of absorption of
one or more components, a choice of absorbent, and an operating temperature
and pressure, there is a minimum absorbent flow rate, given by (69) to (611),
that corresponds to the use of an infinite number of equilibrium stages. For the
use of a finite and reasonable number of stages, an absorbent rate of 1.5 times
the minimum ' is typical. A similar criterion, (612), holds for a stripper.
17. 6. The number of equilibrium stages required for a selected absorbent or
stripping agent flow rate for the absorption or stripping of a dilute solution can
be determined from the equilibrium line, (61), and an operating line, (63) or (6
5), using graphical algebraic, or numerical methods. Graphical methods, such
as Figure 6.11, offer considerable visual insight into stagebystage changes in
compositions of the gas and liquid streams.
7. Rough estimates of overall stage efficiency, defined by (621), can be made
with the correlations of Drickamer and Bradford, (622), O'Connell, (623), and
Figure 6.15 More accurate and reliable procedures involve the use of a small
Oldershaw column , or semitheoretical equations, e.g., of Chan and Fair, based
on mass transfer considerations, to determine a Murphree vaporpoint
efficiency, (630), from which a Murphrtf vapor tray efficiency can be estimated
from (631) to (634), which can then be related to the overall efficiency using
(637).
8. Tray diameter can be determined from (644) based on entrainment flooding
considerations using Figure 6.24. Tray vapor pressure drop, the weeping
constraint, entrainment, and downcomer backup can be estimated from (645),
(664), (665), (666), respectively.
18. 9. Packed column height can be estimated using the HETP, (6
69), or HTU/NTU,(685), concepts, with the latter having a more
fundamental theoretical basis in the twofilm theory of mass
transfer. For straight equilibrium and operating lines, HETP is
related to the HTU by (690), and the number of equilibrium
stages is related to the NTU by (691).
10. Below a socalled loading point, in a preloading region, the
liquid holdup in a packed column is independent of the vapor
velocity. The loading point is typically about 70% of the flooding
point and most packed columns are designed to operate in the
preloading region at from 50% to 70% of flooding. From the
GPDC chart of Figure 6.36, the flooding point can be estimated,
from which the column diameter can be determined with (698
19. 11. One significant advantage of a packed column is its
relatively low pressure drop per unit of packed height, as
compared to a trayed tower. Packed column pressure drop can
be roughly estimated from Figure 6.36 or more accurately from
(6100).
12. Numerous rules of thumb are available for estimating the
HETP of packed columns. However, the preferred approach is
to estimate hog from separate semitheoretical mass transfer
correlations for the liquid and gas phases, such as those of (6
123) and (6124) based on the extensive experimental work of
Billet and Schultes.
13. Determination of theoretical stages for concentrated
solutions involves numerical integration because of curved
equilibrium and/or operating lines.
20. REFERENCES
1. Washburn, E.W., Ed.inChief, International Critical Tables,
McGrawHill, New York, Vol. Ill, p. 255 (1928).
2. Lockett, M., Distillation Tray Fundamentals, Cambridge University
Press, Cambridge, UK, p. 13 (1986).
3. Okoniewski, B.A., Chem. Eng. Prog., 88 (2), 8993 (1992).
4 Sax, N.I., Dangerous Properties of Industrial Materials, 4th ed., Van
Nostrand Reinhold, New York, pp. 440441 (1975).
5. Lewis, W.K., Ind. Eng. Chem., 14, 492497 (1922).
6. Drickamer, H.G., and J.R. Bradford, Trans. AICHE, 39, 319360
(1943).
7. Jackson, R.M., and T.K. Sherwood, Trans. AIChE, 37, 959(1941).
8. S O'Connell, H.E., Trans. AIChE, 42, 741755 (1946).
9.Walter, J.F., and T.K. Sherwood, Ind. Eng. Chem., 33, 493XH
(1941).
10. Edmister, W.C., The Petroleum Engineer, C45C54 (Jan. 1949).
21. 11. Lockhart, F.J., and C.W. Leggett, in K.A. Kobe and J.J. McKetta,
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