Simulation Of Unique Pressure Changing Steps And ... · Simulation Of Unique Pressure Changing...

27
Simulation Of Unique Pressure Changing Steps And Situations In Psa Processes Armin D. Ebner, Amal Mehrotra, James C. Knox, M. Douglas LeVan, and James A. Ritter Department of Chemical Engineering, University of South Carolina, Columbia, SC ([email protected]) Marshall Space Flight Center, National Aeronautics and Space Administration, Huntsville, AL, USA Department of Chemical Engineering, Vanderbilt University, Nashville, TN, USA A more rigorous cyclic adsorption process simulator is being developed for use in the development and understanding of new and existing PSA processes. Unique features of this new version of the simulator that Ritter and co-workers have been developing for the past decade or so include: multiple absorbent layers in each bed, pressure drop in the column, valves for entering and exiting flows and predicting real-time pressurization and depressurization rates, ability to account for choked flow conditions, ability to pressurize and depressurize simultaneously from both ends of the columns, ability to equalize between multiple pairs of columns, ability to equalize simultaneously from both ends of pairs of columns, and ability to handle very large pressure ratios and hence velocities associated with deep vacuum systems. These changes to the simulator now provide for unique opportunities to study the effects of novel pressure changing steps and extreme process conditions on the performance of virtually any commercial or developmental PSA process. This presentation will provide an overview of the cyclic adsorption process simulator equations and algorithms used in the new adaptation. It will focus primarily on the novel pressure changing steps and their effects on the performance of a PSA system that epitomizes the extremes of PSA process design and operation. This PSA process is a sorbent-based atmosphere revitalization (SBAR) system that NASA is developing for new manned exploration vehicles. This SBAR system consists of a 2-bed 3-step 3-layer system that operates between atmospheric pressure and the vacuum of space, evacuates from both ends of the column simultaneously, experiences choked flow conditions during pressure changing steps, and experiences a continuously changing feed composition, as it removes metabolic CO2 and H20 from a closed and fixed volume, i.e., the spacecraft cabin. Important process performance indicators of this SBAR system are size, and the corresponding CO2 and H20 removal efficiencies, and N2 and O2 loss rates. Results of the fundamental behavior of this PSA process during extreme operating conditions will be presented and discussed. https://ntrs.nasa.gov/search.jsp?R=20080013427 2020-04-03T16:16:22+00:00Z

Transcript of Simulation Of Unique Pressure Changing Steps And ... · Simulation Of Unique Pressure Changing...

Page 1: Simulation Of Unique Pressure Changing Steps And ... · Simulation Of Unique Pressure Changing Steps And Situations In Psa Processes Armin D. Ebner, Amal Mehrotra, James C. Knox,

Simulation Of Unique Pressure Changing Steps And Situations In Psa Processes

Armin D. Ebner, Amal Mehrotra, James C. Knox, M. Douglas LeVan, and James A.

Ritter

Department of Chemical Engineering, University of South Carolina, Columbia, SC

([email protected])

Marshall Space Flight Center, National Aeronautics and Space Administration,

Huntsville, AL, USA

Department of Chemical Engineering, Vanderbilt University, Nashville, TN, USA

A more rigorous cyclic adsorption process simulator is being developed for use in the

development and understanding of new and existing PSA processes. Unique features of

this new version of the simulator that Ritter and co-workers have been developing for

the past decade or so include: multiple absorbent layers in each bed, pressure drop in the

column, valves for entering and exiting flows and predicting real-time pressurization

and depressurization rates, ability to account for choked flow conditions, ability to

pressurize and depressurize simultaneously from both ends of the columns, ability to

equalize between multiple pairs of columns, ability to equalize simultaneously from

both ends of pairs of columns, and ability to handle very large pressure ratios and hence

velocities associated with deep vacuum systems. These changes to the simulator now

provide for unique opportunities to study the effects of novel pressure changing steps

and extreme process conditions on the performance of virtually any commercial or

developmental PSA process.

This presentation will provide an overview of the cyclic adsorption process simulator

equations and algorithms used in the new adaptation. It will focus primarily on the

novel pressure changing steps and their effects on the performance of a PSA system that

epitomizes the extremes of PSA process design and operation. This PSA process is a

sorbent-based atmosphere revitalization (SBAR) system that NASA is developing for

new manned exploration vehicles.

This SBAR system consists of a 2-bed 3-step 3-layer system that operates between

atmospheric pressure and the vacuum of space, evacuates from both ends of the column

simultaneously, experiences choked flow conditions during pressure changing steps,

and experiences a continuously changing feed composition, as it removes metabolic

CO2 and H20 from a closed and fixed volume, i.e., the spacecraft cabin. Important

process performance indicators of this SBAR system are size, and the corresponding

CO2 and H20 removal efficiencies, and N2 and O2 loss rates. Results of the fundamental

behavior of this PSA process during extreme operating conditions will be presented and

discussed.

!

https://ntrs.nasa.gov/search.jsp?R=20080013427 2020-04-03T16:16:22+00:00Z

Page 2: Simulation Of Unique Pressure Changing Steps And ... · Simulation Of Unique Pressure Changing Steps And Situations In Psa Processes Armin D. Ebner, Amal Mehrotra, James C. Knox,

iiili(

;i

iilil_

Simulation of Unique Pressure ChangingSteps and Situations in PSA Processes

Armin D. Ebner, _ Amal Mehrotra, _ James C. Knox, 3 M.

Douglas LeVan, 2 and James A. Ritter 1

1Department of Chemical Engineering, University of South CarolinaColumbia, SC

2Department of Chemical Engineering, Vanderbilt UniversityNashville, TN

3Marshall Space Flight Center, NASA

Huntsville, AL

AIChE 2007 Annual Meeting

Salt Lake City, UtahNovember 6, 2007

Page 3: Simulation Of Unique Pressure Changing Steps And ... · Simulation Of Unique Pressure Changing Steps And Situations In Psa Processes Armin D. Ebner, Amal Mehrotra, James C. Knox,

Introduction1. Rigorous cyclic adsorption process simulator (Ddaspk-Fortran) being

developed to assist in the design, development and understanding of new

and existing PSA processes.

2. Unique features of this simulator include:

• Multiple absorbent layers and columns

• Pressure drop in the column

• Entering and exiting flows defined by constant flow, valve equations,

or choke flow approaches (Isentropic, Fanno, etc.)

• Interaction with other processes: cabin, distillation units, etc.

• Simultaneous feed, exit, pressure varying steps through multiple ports

• Ability to handle large P ratios and v's associated with deep vacuum

systems.• Equalization between pairs of columns (single and dual ended) in

progress.

These features provide for unique opportunities to study the

performance of virtually any commercial or developmental PSA

process under extreme process conditions.

Page 4: Simulation Of Unique Pressure Changing Steps And ... · Simulation Of Unique Pressure Changing Steps And Situations In Psa Processes Armin D. Ebner, Amal Mehrotra, James C. Knox,

1

!

ObjectivesFocus primarily on a particular PSA system that NASA is

developing: referred to as the sorbent-based atmosphere

revitalization (SBAR) system

o:. this PSA system is unique because it uses deep space

vacuum for regeneration in lieu of processed air as purge

Describe NASA's PSA System, with emphasis on the alternative

regenerative steps that NASA has developed to further improve

performance: single, dual, and triple ended blowdown

Show validation of the PSA process simulator against NASA's

experimental data of an 8.8 L dual blowdown system

Use the simulator to discuss the role of these regenerative steps

on PSA performance in terms of H20 and CO 2 removalefficiencies

This SBAR system might be used in a new Crew Exploration

Vehicle (CEV) to remove metabolic H20 and CO 2 from cabin air.

Page 5: Simulation Of Unique Pressure Changing Steps And ... · Simulation Of Unique Pressure Changing Steps And Situations In Psa Processes Armin D. Ebner, Amal Mehrotra, James C. Knox,

Schematic of Base Case Column Simulated for Water andCarbon Dioxide Removal from Cabin Air

MSFC SBAR

Experimental System

V b = 8.88 L

L b = 0.2654 m

rb = 0.1032 m

HCT = 450 s

D Zeolite 13X

_-] Zeolite 5A

F (10-14.5 SCFM)

2.357 kg

4.062 kg

LP

_- 34%

66%

Page 6: Simulation Of Unique Pressure Changing Steps And ... · Simulation Of Unique Pressure Changing Steps And Situations In Psa Processes Armin D. Ebner, Amal Mehrotra, James C. Knox,

Schematic Diagram and Cycle Sequencing of VSACycle Used for Air Revitalization

F

FP SEB F SEB

/

e L

11r

J[ U

/

t

I I

Pt

_V

tL

m i

lV

To

Space

F

ToCabin

2

I I

P.[

,--li

I I

Pt

'V[L

I I

Ir

To

Space

FP

SEB

!

' FI

IIi SEB

I

!

' SEBSEB,

I

FP , F

I

TimeY

SBAR Cycle Step Times

tF =420 s

tsEB = 30 s

tsE B = 420 s

tFp-- 30 s

SEB: single ended blowdown

Page 7: Simulation Of Unique Pressure Changing Steps And ... · Simulation Of Unique Pressure Changing Steps And Situations In Psa Processes Armin D. Ebner, Amal Mehrotra, James C. Knox,

Schematic Diagram and Cyc_e Sequencing of VSACycle Used for Air Revitalization

F

FP SEB F DEB

ToCabin

2

/ I I

PL P t

T

I I I

PP[

1

tL

F

To

Space

I

t

I

FP ' F!

!

ISEB , DEB

!

' DEBSEB,

I

IFP , F

I

Time

t'

L tF - 420 SI

tsEB - 30 s

, tDEB 420 S

SBAR Cycle Step Times

To

Space

tFp-30 s

SEB: single ended blowdownDEB: dual ended blowdown

Page 8: Simulation Of Unique Pressure Changing Steps And ... · Simulation Of Unique Pressure Changing Steps And Situations In Psa Processes Armin D. Ebner, Amal Mehrotra, James C. Knox,

Schematic Diagram and Cycle Sequencing of VSACycle Used for _ir Revitalization

F

FP SEB

/

e L

11r

J¢ U

/

tTo

Space

F

To

Space

!

III

,!

Time

!

'TEB!

I

!

!

I

SBAR Cycle Step Times

tv = 420 s

tSEB = 30 S

tTEB = 420 S

tFp-- 30 s

SEB: single ended blowdown

TEB: triple ended blowdown

Page 9: Simulation Of Unique Pressure Changing Steps And ... · Simulation Of Unique Pressure Changing Steps And Situations In Psa Processes Armin D. Ebner, Amal Mehrotra, James C. Knox,

Simulator InputBed Characteristics and Transport Properties

MSFC SBAR Experimental System

bed layer fraction (%)

porosity

pellet density (kg m -3)

heat capacity (kJ kg -1 K -1)

heat transfer coefficient (kW m -2 K-l) a

mass transfer coefficients (s -1)

H20

CO 2

02

N 2

r b (mm)p,eff

13X 5A

66% 34%

0.26 0.35

1100 1201

1.10 0.84

0.0017 0.0017

0.00550 0.00310

0.00150 0.00067

0.001 0.001

0.001 0.001

3.3 2.1

Page 10: Simulation Of Unique Pressure Changing Steps And ... · Simulation Of Unique Pressure Changing Steps And Situations In Psa Processes Armin D. Ebner, Amal Mehrotra, James C. Knox,

Motivation: Single vs Dual Ended BlowdownPressure profiles @ End of Blowdown Step

Single Dual

_LJ

ii

15 S (_1'M

6.0800 _ .....

I7O0

€_

0

n

600

iO0

LO0

_00

>>

Final State of Step

Cycle 40

5.0

4-- Press urlzation

........Feed t,=, Blowdown_single

I4,0

3.0

O2.0 _"

n

1.0

I

!oo

IOO

o

o o.1 o.2 0.3 0.4 0.5 o.6 0.7 o.8 0.9 1

Z/L

iv

O.

800

TO

6.0

700

600

;00

,00

;00

_00 !_ __' _--0O S'_

___=_[................

--r °"

Final State of Step

Cycle 40

5.0

4.0

3.0

2.0

F .-..-> ..... 1

Press ui:iZation

Feed

Blowdown_single ._ 1.0Blowdown dual

0 0.1 0.2 0.3 0A 0.5 0.6 0.7 0.8 0.9 t

Z/L

,.£,It,.

o

O..

Page 11: Simulation Of Unique Pressure Changing Steps And ... · Simulation Of Unique Pressure Changing Steps And Situations In Psa Processes Armin D. Ebner, Amal Mehrotra, James C. Knox,

Motivation: Single vs Dual Ended BlowdownCycle Performance Parameters Zeolite System

15 ,_,Z[ M

Single Dual

100

90

o_" 8O

¢n 70

L9"o 6O03

IJ.

_'6 50e,,,o 40

_ 30

20

10

_._=_ H20, Blowdown Heavy End/

/

CO2, Biowdown, Heavy End

CO2, Light Product

H20, Bed Accumulation

in E_2,=B_dRI_cI_!FRuI_R=Io_II_ 1 1 ,i=

0 10 20 30 40 50

Time (hr)

1 1 i 1

60 70 80

H20, Blowdown Heavy End

H20, Blowdown, Light End

H20, Light Product

CO2, Blowdown, Light End i

CO2, Blowdown, Heavy End

BIIIlll IB1 l l l

CO2, Light Product

H20, Bed Accumulation

Bed Accumulation

0 10 20 30 40 50 60 70 80

Time (hr)

Page 12: Simulation Of Unique Pressure Changing Steps And ... · Simulation Of Unique Pressure Changing Steps And Situations In Psa Processes Armin D. Ebner, Amal Mehrotra, James C. Knox,

Modeling the SBAR DEB Experimental SystemTemperature History Profiles at Three Bed Locations

120 h

F = 13.5 SCFM

V b : 8.88 L

HCT = 450 s

t F = 420 s

tsE B = 30 s

tDEB = 420 S

tFp = 30 S

90

85

80

75

%.. 70k--

65

6O

55

50

--z = 0.00 o exp,z = 0.00

--z = 0.50 exp,z = 0.50

--z = 1.00 o exp,z = 1.00

! I

0 5

I

10

i I

15

time (min)

Cycles 481-482i I i I

20 25 30

Page 13: Simulation Of Unique Pressure Changing Steps And ... · Simulation Of Unique Pressure Changing Steps And Situations In Psa Processes Armin D. Ebner, Amal Mehrotra, James C. Knox,

Modeling the SBAR DEB Experimental SystemPressure History Profiles at Three Bed Locations

120 h

F = 13.5 SCFM

V b -- 8.88 L

HCT= 450 s

t F = 420 s

tSEB = 30 S

tDEB = 420 S

tFp = 30 SA

L_O

t_.

4

3

2

1

0

t t

--z = 0.00 o exp, z = 0.00

--z = 0.50 exp, z - 0.50

--z = 1.00 exp, z = 1.00

i

0 5

ICycles 481-482

I

10 15 20

time (min)

<

o

I I I

25 30

Page 14: Simulation Of Unique Pressure Changing Steps And ... · Simulation Of Unique Pressure Changing Steps And Situations In Psa Processes Armin D. Ebner, Amal Mehrotra, James C. Knox,

Modeling the SBAR DEB Experimental SystemPco2 History Profiles at Two Bed Locations

120 h

F = 13.5 SCFM

V b = 8.88 L

HCT = 450 s

tF = 420 s

tSEB = 30 S

tar B = 420 S

tFp = 30 S

t_L_

OV

O4Oto

(1.

8

7

6

5

4

3

2

--z = 0.00 _ exp, z = 0.00

--z = 1.00 exp, z = 1.00

0

0 5

Cycles 481-482

10 15

time (min)

20 25 30

Page 15: Simulation Of Unique Pressure Changing Steps And ... · Simulation Of Unique Pressure Changing Steps And Situations In Psa Processes Armin D. Ebner, Amal Mehrotra, James C. Knox,

Modeling the SBAR DEB Experimental SystemBed Profiles at End of Steps for P, T, PH2O and Pco2

120 h

F = 13.5 SCFM

V b -- 8,88 L

HCT= 450 s

tv = 420 s

tsE _ = 30 s

tDwB = 420 s

tFp = 30 S

120

11o t End State of Step

Cycle 480

10

9

8

7

i -,_- Pressurization

.........Feed

_ Blowdown_duai

10

8

6

5

4

3

End State of Step

Z/L

\\

\

End State of Step

cycle 480

_- Pressurization

.......Feed

Blowdown_dual

Blowdown_duai

•_ Pressurization

Feed

End State of StepC_cle 480

0.1 02. 03 0.4 0.5 0,8 0.7 0.8

Z/L

0.9 1

80O

790

780

770

760

750

740

730

720

710

700

Page 16: Simulation Of Unique Pressure Changing Steps And ... · Simulation Of Unique Pressure Changing Steps And Situations In Psa Processes Armin D. Ebner, Amal Mehrotra, James C. Knox,

!ii.

Modeling the SBAR DEB Experimental SystemSummary of Modeling vs Experimental Results of

Eight Different Test Runs

'ii

Page 17: Simulation Of Unique Pressure Changing Steps And ... · Simulation Of Unique Pressure Changing Steps And Situations In Psa Processes Armin D. Ebner, Amal Mehrotra, James C. Knox,

Modeling the SBAR DEB Experimental SystemSummary of Modeling vs Experimental Results of

Eight Different 7rc._stRuns: H20 Removal

Page 18: Simulation Of Unique Pressure Changing Steps And ... · Simulation Of Unique Pressure Changing Steps And Situations In Psa Processes Armin D. Ebner, Amal Mehrotra, James C. Knox,

_!i'i

Modeling the SBAR DEB Experimental SystemSummary of Modeling vs Experimental Results of

Eight Different Test Runs

.Qm

5.X

:>oE

n_04

o(3

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0.0

0.0 0.1

I CO2 Rem°val I I Cycle Bed Temperatures I

0.2 0.3 0.4 0.5 0.6 0.7 0.8

CO2 Removal, model, Ib/h

100

90

LI.o 805.x(9

_ 70

_ 6OEI--

50

40

• Maximum

e Minimum52 42 @t 43

12 20

• 18 23

54

12

_3 Z/L=0.5

4O 50 60 70 80 90

Temperature, model, °F

100

Page 19: Simulation Of Unique Pressure Changing Steps And ... · Simulation Of Unique Pressure Changing Steps And Situations In Psa Processes Armin D. Ebner, Amal Mehrotra, James C. Knox,

Triple Ended BlowdownEffect of Location of Third Exhaust Port

F

FP SEB

/

eL

JL U

m

t

I I

PI

'r[L

_r

To

Space

F

F DEB

To

Cabin

I

P

II

[

I

L

m ii

P_

,p,

IL"_

I I

_r

To

Space

Test Run 18F = 13.5 SCFM

V b = 8.88 LHCT = 450 s

tv = 420s

tSE D ---- 30S

tDE D = 420 S

tFp = 30 S

Third Port Location

z/L = 0.2, 0.3, 0.4, or 0.5

Page 20: Simulation Of Unique Pressure Changing Steps And ... · Simulation Of Unique Pressure Changing Steps And Situations In Psa Processes Armin D. Ebner, Amal Mehrotra, James C. Knox,

Triple vs Dual Ended BlowdownBed Pressure Profiles at the End of the Blowdown step

Significant Increase of Driving Force

=A

L_L_

n

1.2

1.0

0.8

0.6

0.4

0.2

0.0

0.0

_ 0.3 0.4 0.5

Double

\

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

z/L

_J=

.=o j=(

Page 21: Simulation Of Unique Pressure Changing Steps And ... · Simulation Of Unique Pressure Changing Steps And Situations In Psa Processes Armin D. Ebner, Amal Mehrotra, James C. Knox,

Triple vs Dual nded BlowdownHistory of H20 and CO 2 Removal Per Cycle

I DUAL I I Trip.e,z,,=0. 0I110

100

90

80

"O 70

14. 60

Oe- 50O

40¢J

=" 30LI.

20

10

0

_..___ C HO220' ;BiBol°wWddo °wWn,nHHeeaavVyYEEnndd

i

0

C02, Light Product

C02, Blowdown, Light End

! I I I i I ! I ! I I ! I I I I I | i I • I .

10 20 30 40 50 60 70 80 90 100 110 1200

Time (hr)

H20, Blowdown, Heavy Product End

__ CO2, Blowdown, Heavy End

--[---_-xtZiZ..................... _±_g_-_-_d_,_t ...... -....=--

_____C_, B_wdown, Light End

r • I i I . I , I l I I I ! I I I I | • I . I i

10 20 30 40 50 60 70 80 90 100 110 120

Time (hr)

Page 22: Simulation Of Unique Pressure Changing Steps And ... · Simulation Of Unique Pressure Changing Steps And Situations In Psa Processes Armin D. Ebner, Amal Mehrotra, James C. Knox,

Triple vs Dual Ended BlowdownHistory of H20 and CO 2 Removal Per Cycle

I DUAL I I Triple, z/L=0.40 I110

100

90

A

0_ 80

"o 7O

_ 60

O

so40

_- 30IJ.

20

H20, Blowdown Heavy End

_"_.---_ CO2,,Blowdown, Heavy Endii ,,,,mill

C02, Light Product .

C02, Blowdown, Light End

10

0

0 10 20 30 40 50 60 70 80 90 100 110

Time (hr)

H20, Blowdown Heavy End

CO2, Blowdown, Light End

1200 10 20 30 40 so 60 70 80 90 100 110 120Time (hr)

Page 23: Simulation Of Unique Pressure Changing Steps And ... · Simulation Of Unique Pressure Changing Steps And Situations In Psa Processes Armin D. Ebner, Amal Mehrotra, James C. Knox,

Triple vs Dual Ended BlowdownHistory of H20 and CO 2 Removal Per Cycle

I DUAL I I Triple, z/L=0.30 I

110

100

9O

A

80

"o 7O(DOu. 60N_

o50

Co

4OO

_- 30IJ.

2O

10

0

H20, Blowdown Heavy End

Blowdown, Heavy End

CO2, Light Product

CO2, Blowdown, Light End

0 10 20 30 40 50 60 70 80 90

Time (hr)

100 110

H20, Blowdown Heavy End

CO2, Blowdown, Heavy End

120 0 10 20 30 40

CO2 Blowdown ht End

50 60 70 80 90 100

Time (hr)

110 120

Page 24: Simulation Of Unique Pressure Changing Steps And ... · Simulation Of Unique Pressure Changing Steps And Situations In Psa Processes Armin D. Ebner, Amal Mehrotra, James C. Knox,

Triple vs Dual Ended BlowdownHistory of H20 and CO 2 Removal per Cycle

i_i!i

I ou,, I I Trip.e,z,,=0.20I110

100

90

80v

"o 7O

(9u. 60s4-.

O50

cO

40

"_ 30

20

10

0

Blowdown Heavy End

Blowdown, Heavy End

CO2, Light Product

CO2, Blowdown, Light End

H20, Blowdown, Heavy End

CO2, Blowdown, Heavy EndCO2, Light Product

CO2, Blowdown, Light EndI I . I . I . I n I I I ! I I I • i . I . I ,t

0 10 20 30 40 50 60 70 80 90 100 110 120 0 10 20 30 40 50 60 70 80 90 100 110 120Time (hr) Time (hr)

Page 25: Simulation Of Unique Pressure Changing Steps And ... · Simulation Of Unique Pressure Changing Steps And Situations In Psa Processes Armin D. Ebner, Amal Mehrotra, James C. Knox,

Triple vs Dual Ended BlowdownH20 and CO 2 Removal after 120 hr

I Optimal Third Port Location I

U)

Om=

--!Balm

"0O

m

OO

O

Nr-

m

Q.

m.

N

r-

Conditions Modeling Results

z o -_ 5" 5" -,1 5- o o z= m m -- -- _ _ O O _-_ _o

o --I --I "o _ ;0 --i :;0 _ ::0 ::0

o 3 3 o z _. 3 3 3 3 3• " m co 0 _ m- "- - "_ O O O O

3 Et p .O _ - < < < <3 = = O o _ m _'- "- _ --

..,, mJl 9

=

co

---I

"0m

8.88

0.5 8.88

0.4 8.88

0.3 8.88

0.2 8.88

7.5

7.5

7.5

7.5

7.5

7.0 ==

7,0

7.0

7.0

7.0

5.0 9.1 13.5 69.9 0.47 0.74 0.49 1.00

5.0 9.1 13.5 69.9 0.50 0.79 0.49 1.00

5.0 9.1 13.5 69.9 0.55 0.86 0.49 1.00

5.0 9.1 13.5 69.9 0.54 0.85 0.49 1.00

Page 26: Simulation Of Unique Pressure Changing Steps And ... · Simulation Of Unique Pressure Changing Steps And Situations In Psa Processes Armin D. Ebner, Amal Mehrotra, James C. Knox,

Conclusions

A description of the new NASA SBAR PSA system for H20

and CO 2 removal, with particular emphasis on its purgeless

deep vacuum regenerative steps has been given

Regeneration consisted of blowdown steps subject to deep

vacuum through an increasing number of evacuation ports, i.e.

single, dual and triple ended blowdown was studied,

The USC PSA process simulator, for which adsorbent and

adsorbate properties were independently obtained, successfully

predicted NASA's experimental results of a dual ended system.

The USC PSA process simulator was also used to discern the

role of the regenerative steps on the performance of NASA's

SBAR PSA system.

The USC PSA process simulator is currently being

used in other projects of equal complexity.

Page 27: Simulation Of Unique Pressure Changing Steps And ... · Simulation Of Unique Pressure Changing Steps And Situations In Psa Processes Armin D. Ebner, Amal Mehrotra, James C. Knox,

;ii

Acknowledgements

Funding being provided by theNASA MSFC

is greatly appreciated!

Thank You!