PRESSURE SWING ADSORPTION REACTORS - SIMULATION OF 3-STEP ONE-BED PROCESS

A three-step (feed, delay, and purge), one-column pressure swing adsorption reactor has been analyzed. An equilibrium model taking into account species mass balances, overall mass balance, momentum balance, reaction rate, and nonlinear multicomponent adsorption equilibrium isotherms was derived to describe the PSA reactor process. Numerical solution of model equations was obtained by using the method of orthogonal collocation on finite elements, and simulation results showed that 10-20% higher conversion than reaction equilibrium conversion in afixed-bed reactor could be obtained from the PSA reactor for a reversible reaction A reversible B + C, such as dehydrogenation of ethane to ethylene and hydrogen on cadmium-exchanged zeolites, where only product B was assumed to be adsorbed. When both reactant A and product B are adsorbed, 10% higher conversion over the reaction equilibrium limit was observed for pure reactant feed. The effects of system and operating parameters on the process performance of the PSA reactor have been studied, as well as the bed dynamics of the PSA reactor at the cyclic steady state.