Combined Continuous/Discrete Variable Rigorous Dynamic Simulation of H₂/CO Separation PSA process

A rigorous dynamic simulation is performed in binary gas mixture H2/CO(70:30 vol%) to improve design and operation technology of PSA(Pressure Swing Adsorption) processes. As rigorous models of PSA processes include combined continuous/discrete variables and some PDEs essentially, it is difficult to treat those heterogeneous variables and solve PDEs exactly. Through the use of the State-Task-Network concept and special numerical techniques such as OCFEM, those combined PDEs can be solved efficiently in this study. A rigorous dynamic model for a PSA process contains a LRC model for equilibrium adsorption isotherms, an Ergun equation for expressing the pressure drop in a bed, and valve equations to compute the boundary pressure change of the bed. As the result of the continuous dynamic simulation of 100 operating cycles, the unsteady-state appears in the early period and the cyclic steady-state come out about 11-l3th cycle. As time goes by, valve equations change the pressure at each end of the bed in pressurization, countercurrunt-depressurization and pressure equalization steps. The H2 purity and the recovery is 99.99% and 86.73% respectively, which is slightly higher than the experimental data. Main contribution of this study includes supplying fundamental technologies of handling combined variable PSA processes by developing rigorous models.