THE EFFECT OF THE TIME LENGTH OF PRESSURE CHANGING STEPS ON CONCENTRATION IN THE GAS-PHASE IN THE PRESSURE SWING ADSORPTION PROCESS

Abstract

To investigate the effect of the time length of pressure changing steps theoretically, mathematical expressions for the gas-phase concentration of pressure changing steps in the pressure swing adsorption process were derived under the simple initial conditions and compared with numerical solutions using the orthogonal collocation method. At this time, the linear driving force model was used. We examined whether the time length of the pressure changing steps influenced the concentration in the gas phase for various mass transfer coefficients. The time length did not affect the concentration in the gas phase for the two extreme cases, i.e., a very large mass transfer coefficient or a very small mass transfer coefficient, but the effect of time length was large for a small mass transfer coefficient. A detailed discussion of the pressure-changing steps is included.