(719x) Comparison of H2 Psa Processes from Low Concentration of Hydrogen Feed

Hydrogen is considered to be one of the most important chemicals used in the chemical and petroleum industries. Furthermore, hydrogen can be used as a general purpose energy source for space heating, electric power generation, and transportation fuel. These potential uses have resulted in a huge increase in hydrogen demand.

The simulation study of PSA processes are studied to produce higher than 90% H2 from 38% feed with high recovery. The feed contains CO2, N2, CO and CH4 as impurities. The PSA processes are simulated by a non-isothermal dynamic model using gPROMS.

The performance of two-bed PSA is compared to that of four-bed PSA. In addition, the separation performance of the PSA using single adsorbent is also compared to that of the PSA using layered bed. Although the two-bed PSA can produce the target purity, the recovery is low due to the purge gas. However, the four-bed PSA can produce higher than 90% H2 with very high recovery by minimizing purge gas and twice equalization steps. Furthermore, since the N2 works as a main impurity in product, the layered bed PSA can control the product quality more efficiently than the single adsorbent bed PSA. To maximize the purity and recovery, the ratio of adsorbent in the bed plays a key role in the PSA process. Moreover, it is important to control the concentration profile of CO2 in the bed because of its strong adsorption of adsorbent.