Page 299 - Pressure Swing Adsorption

PRESSURE SWING ADSORPTION
276 EXTENSIONS OF THE PSA CONCEPT 277

(

~------------------r:i \
Pressunzat1on
with feed -
Product
Withdrawal -
Co-0Jrren1
BD -
l Counter
I -BD
0 Current
n
Counter
\ - Current
Purge
Product
- Pressunzanon
2
(L
Cl'.
0 ~
D Cl
<D "' w PISTON I PISTON 2
mo w PRESSURE
(L
V)
w
0
>-
()
Figure 7.9 TCPSA system showing piston movements anct associated flows and
pressure changes.
0
D
"1'-0
mmO
7 .2.2 Comparison with Conventional PSA
It is instructive to cxoiorc, m greater detail, the rClationshio between a
TCPSA system and a conventional PSA process. Figure 7.9 shows the
sequence of the piston movements and the associated ;pressure changes and
gas flows. The corresoonding seQuence of discrete steps for an equivalent
PSA cycle 1s also mdicated:
L--~----r--.----,---,------,_.::,t o
"' "' <D "' 0 Partial pressurizat10n with light product end.
Pressunzation with feed (contammg heavy product) from the feed end.
High-pressure flow from the feed enct with removal of a prooortion of the
light product.
(~qspD wD/,<bp/w5) JJ.1/\U.OOOm::Jd Ol.dl03dS
• Cocurrent blowctown (to light product end).
• Countercurrent blowctown (with removal of a proportion of heavy product
from feed end).
• Countercurrent purge, at low pressure, with light product.