Removal of CO and CO ₂ from ammonia synthesis gas by pressure swing adsorption with layered bed

A layered Pressure Swing Adsorption (PSA) process with activated carbon and NA as adsorbents was developed for the removal of CO and CO ₂ from ammonia synthesis gas. The simulation results with Aspen-Adsim software show that the pressure difference Δp of the Provide Purge (PP) step determines the purge gas amount that has a great effect on the process performance. With the increase of Δp, the process performance would be improved. Besides, the number of pressure equalization used in one PSA cycle can also affect the process performance. Under the same Δp, when the three pressure equalizations in one cycle are reduced to the two ones, less amount of adsorbent would be used, and thus a higher yield is reached, but much more exhaust gas would be produced respectively.