Page 336 - Pressure Swing Adsorption

I APPENDIX
B

!
1
l
l Collocation Form of the
PSA Model Equations

B.1 Dimensionless Form of the LDF Model Equations

The discussion here 1s restncted to a two-component system (subscripts A
and B denote the components). The sum of the mole fractions of the two
comoonents m the gas phase at every ooint in the bed is eaual to one.
· Therefore, soivmg for only one component in the gas phase 1s sufficient; the
concentration of the other component in the gas phase is obtained by
difference. The eauat1ons are deveJoped in general terms for a variable
pressure step with flow at the coiumn inlet.
Applying ideal gas law [cA = CyAfyA/(R,T )] to the component and
0
overall mass balance cctuations (Eqs. l and 4 m Table 5.2), we obtain:
ayA _ D a'yA _ {ov _!_ apl _ . ayA
a1 - L az' YA\ az + P a1 , v az (B.I)
;1 - e RgTo aqA
- -e- ---V- di
av + _!_ ap = _ i - e R,To ( aqA + aqs ')
az P a, e P . a, at , (B.2)
Substituting Ea. B.2 into B. l yields:
2
oyA o yA ayA I - e R,To ( aqA aq \
8
a,=DLaz' -uaz+-,-1" (yA- l)a, + YA'a( I
(B.3)

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