# Start-Up of a Plate Gas Absorption Unit

Start-Up of a Plate Gas Absorption Unit

The start-up behavior of a six-plate gas absorption unit is described by the following equations:

τ=α-(α+1)+

d

x

n

dt

x

n+1

x

n

x

n-1

n=1,…,6

τ=

H

mV

α=

L

mV

L

V

m=0.72

y

n

x

n

n=1,…,6

x

y

H

x

7

y

0

One can solve the system of ODEs using the built-in Mathematica function NDSolve. An elegant analytical solution was made available by Lapidus and Amundson in 1950 (and later by Acrivos and Amundson, 1955) and is described in detail by J. M. Douglas (see reference below). This Demonstration shows that both methods give the same result for the output gas composition versus time.