(395t) Layered-Bed PSA Process for H2 Recovery From Coal Gas

H₂ syn-gas production by coal gasification has attracted much attention due to a lack of crude oil and global warming. In addition, H₂ mixutres from various sources, which were burned in the processes due to their low quality, are needed to recover H₂ by using an efficient separation process because of a great demand for H₂  as a clean fuel at gas turbine in IGCC and at a furnace in an iron/steel industry. A pressure swing adsorption (PSA) process can suggest a promising process to recover H₂ from a mixture because most of such mixtures were emitted at a high pressure condition.

In the present study, a layered two-bed PSA process was studied for H₂ recovery from coal gas with relatively low H₂ concentrations (H₂/CO₂/CH₄/CO/N₂; 38/50/1/1/10 vol.%). To design an energy-efficient PSA process, adsorption  dynamics were compared among single adsorbent beds and activated carbon/zelite layered beds. For the layered bed, zeolite 13X and zeolite LiX were applied to the adsorption bed. In addition, the breakthrough experiments of various layered beds with different activated carbon/zeolite ratio were performed in the pressure range from 6.5 to 9.5 atm. Based on the dynamic results, the layered two-bed PSA process was performend and the PSA dynamic behaviors were evaluated by a non-isothermal dynamic model.