absorption

Information about absorption

Published on January 4, 2008

Author: Miguel

Source: authorstream.com

Content

Absorption:  Absorption Definition Equipment Packing materials Design considerations: Mass balance High gas flow Mass flow Concentrated systems HTU and NTU Reading: Chap. 13 img.alibaba.com/photo/50678451/Ceramic_Metal_... Definition:  Definition Transfer of a gaseous component (absorbate) from the gas phase to a liquid (absorbent) phase through a gas-liquid interface. Q: What are the key parameters that affect the effectiveness? Q: How can we improve absorption efficiency? Mass transfer rate: gas phase controlled absorption liquid phase controlled absorption Q: Does it matter if it’s gas phase or liquid phase controlled? Equipment:  Equipment Mist Eliminator Liquid Spray Packing Liquid outlet Dirty gas in Spray nozzle Clean gas out Countercurrent packed tower Spray tower Mycock et al., 1995 Redistributor Q: Limitations of a spray tower? Q: Why redistributor? Clean gas out Dirty gas in Slide4:  Berl Saddle Intalox Saddle Raschig Ring Lessing Ring Pall Ring Tellerette Three-bed cross flow packed tower Liquid spray Dry Cell Packing Mycock et al., 1995 Q: Criteria for good packing materials? Slide5:  Design considerations: What are known? What are we looking for? Slide6:  Mass Balance In = Out Slide7:  Clean water Dirty water Clean air Dirty air Slide8:  Generally, actual liquid flow rates are specified at 25 to 100% greater than the required minimum. G = 84.9 m3/min (= 3538 mole/min). Pure water is used to remove SO2 gas. The inlet gas contains 3% SO2 by volume. Henry’s law constant is 42.7 (mole fraction of SO2 in air/mole fraction of SO2 in water). Determine the minimum water flow rate (in kg/min) to achieve 90% removal efficiency. Q: How much is X2 if fresh water is used? What if a fraction of water is recycled? Slide9:  Channeling: the gas or liquid flow is much greater at some points than at others Loading: the liquid flow is reduced due to the increased gas flow; liquid is held in the void space between packing Flooding: the liquid stops flowing altogether and collects in the top of the column due to very high gas flow Problems with high gas flow Gas flow rate is 3538 mole/min and the minimum liquid flow rate is 2448 kg/min to remove SO2 gas. The operating liquid rate is 50% more than the minimum. The packing material selected is 2” ceramic Intalox Saddles. Find the tower diameter and pressure drop based on 75% of flooding velocity for the gas velocity. Properties of air:: molecular weight: 29 g/mole; density: 1.17×10-3 g/cm3. Properties of water:: density: 1 g/cm3; viscosity: 0.8 cp. Slide10:  L: mass flow rate of liquid G: mass flow rate of gas G’: mass flux of gas per cross sectional area of column F: Packing factor : specific gravity of the scrubbing liquid mL: liquid viscosity (in cP; 0.8 for water) (dimensionless) Mass Transfer:  Mass Transfer Two-Film Theory (microscopic view) Cussler, “Diffusion”, Cambridge U. Press, 1991. pG CI pI CL J: flux k: mass transfer coefficient (gas phase flux) (liquid phase flux) (overall flux) Slide12:  Macroscopic analysis of a packed tower Mole balance on the solute over the differential volume of tower (equivalent concentration to the bulk gas pressure) (equivalent pressure to the bulk concentration in liquid) (overall liquid phase MT coefficient) (overall gas phase MT coefficient) 1 2 L’m: molar flux of liquid G’m: molar flux of gas Slide13:  Mole balance on the solute in the gas only NTU? HTU? a: packing area per volume (tower height) Slide14:  Mass balance Equilibrium x1, y1* x1, y1 xZ, yZ* xZ, yZ Alternative solution: Assumptions for dilute/soluble systems? Slide15:  Pure amine Lm = 0.46 gmole/s 0.04% CO2 1.27% CO2 Gm = 2.31 gmole/s C* = 7.3% CO2 in amine Q: A Packed tower using organic amine at 14 oC to absorb CO2. The entering gas contains 1.27% CO2 and is in equilibrium with a solution of amine containing 7.3% mole CO2. The gas leaves containing 0.04% CO2. The amine, flowing counter-currently, enters pure. Gas flow rate is 2.31 gmole/s and liquid flow rate is 0.46 gmole/s. The tower’s cross-sectional area is 0.84 m2. KOGa = 9.34×10-6 s-1atm-1cm-3. The pressure is 1 atm. Determine the tower height that can achieve this goal. Slide16:  Absorption of concentrated vapor Mole balance on the controlled volume Gas flux Liquid flux x1, y1 x1, y1* xZ, yZ* xZ, yZ Slide17:  Mole balance on the gas in a differential tower volume Slide18:  HTU (ft) HTU For a given packing material and pollutant, HTU does not change much. Quick Reflection:  Quick Reflection

Related presentations


Other presentations created by Miguel

Att5 India
27. 03. 2008
0 views

Att5 India

FAPRI Biofuels addendum 2
04. 10. 2007
0 views

FAPRI Biofuels addendum 2

agroterrorism
24. 10. 2007
0 views

agroterrorism

991112 price grid
24. 10. 2007
0 views

991112 price grid

56157
29. 10. 2007
0 views

56157

PMA URS31 IACSDUBAI VANCOUVER
08. 11. 2007
0 views

PMA URS31 IACSDUBAI VANCOUVER

jaipur
28. 11. 2007
0 views

jaipur

MH1
28. 11. 2007
0 views

MH1

ES 832 Lect 4
06. 12. 2007
0 views

ES 832 Lect 4

01guber
25. 10. 2007
0 views

01guber

Moore 16Mar05 Digits vs RDOs
01. 11. 2007
0 views

Moore 16Mar05 Digits vs RDOs

2007FLawards
02. 11. 2007
0 views

2007FLawards

ESD Wood preservatives BH
12. 11. 2007
0 views

ESD Wood preservatives BH

kotlerkeller chapter 14
15. 11. 2007
0 views

kotlerkeller chapter 14

ICATforWCC 002
16. 11. 2007
0 views

ICATforWCC 002

jaguar
20. 11. 2007
0 views

jaguar

Uganda
24. 10. 2007
0 views

Uganda

Predation07
30. 12. 2007
0 views

Predation07

Selim hydropower
22. 11. 2007
0 views

Selim hydropower

InstantMessaging
30. 12. 2007
0 views

InstantMessaging

2005 skin ppt
03. 01. 2008
0 views

2005 skin ppt

Crypto durant la 2nd guerre
04. 01. 2008
0 views

Crypto durant la 2nd guerre

Tech Preso
07. 01. 2008
0 views

Tech Preso

Andhra Pradesh
07. 01. 2008
0 views

Andhra Pradesh

Pumpkins Squash
05. 11. 2007
0 views

Pumpkins Squash

Target System Design Update
07. 11. 2007
0 views

Target System Design Update

SgrA Reid
15. 11. 2007
0 views

SgrA Reid

The Next Great Generation
02. 10. 2007
0 views

The Next Great Generation

EigenTrust
18. 12. 2007
0 views

EigenTrust

Carlstrom
14. 11. 2007
0 views

Carlstrom

MTTppsb
05. 11. 2007
0 views

MTTppsb

installingvaporrecov ery
06. 11. 2007
0 views

installingvaporrecov ery

ShiftShare
20. 02. 2008
0 views

ShiftShare

ch5FamilyCharacteris tics
24. 02. 2008
0 views

ch5FamilyCharacteris tics

zuccaarl08
27. 02. 2008
0 views

zuccaarl08

Bill Presentation
05. 03. 2008
0 views

Bill Presentation

1 HGIS011006
25. 10. 2007
0 views

1 HGIS011006

matmata
12. 12. 2007
0 views

matmata

SKADS MCCT Controllers 22032007
14. 03. 2008
0 views

SKADS MCCT Controllers 22032007

WSISRO Openinghbn110702
30. 03. 2008
0 views

WSISRO Openinghbn110702

cert microsoft 03
28. 11. 2007
0 views

cert microsoft 03

g rime
06. 11. 2007
0 views

g rime

MalaysiaMar2206
13. 04. 2008
0 views

MalaysiaMar2206

Buildup Activities
22. 11. 2007
0 views

Buildup Activities

Unit 5 1 2004
01. 01. 2008
0 views

Unit 5 1 2004

rm1910
30. 10. 2007
0 views

rm1910

TRIMS InvClimate Eng
26. 10. 2007
0 views

TRIMS InvClimate Eng

02 06 chistov
27. 09. 2007
0 views

02 06 chistov

BioBank SheilaCasserly
28. 09. 2007
0 views

BioBank SheilaCasserly

atividadefisicaeobes idade
28. 12. 2007
0 views

atividadefisicaeobes idade

code invaders
06. 11. 2007
0 views

code invaders

saghala Cedric Patin
28. 11. 2007
0 views

saghala Cedric Patin