Pressure swing adsorption hydrogen production

Fig. 2. Hydrogen production flow sheet showing steam reforming, shift, and pressure swing adsorption (PSA). BFW = boiling feed water.

In hydrogen fuel supply schemes using coal as feedstock, the same gasification processes as for the production of CTL fuels are applied. The synthesis gas from the gasifier is then converted to hydrogen by CO shift and pressure-swing adsorption (see Table 7.20). 

Pressure swing adsorption (PSA) processes are widely applied industrially for gas separations. Applications are numerous and include hydrogen and helium recovery and purification, air drying, the production of oxygen from air, and the separation of normal paraffins from isoparaffins. 

The third process used in the production of carbon dioxide is pressure swing adsorption. The feed gas usually contains approximately 20 percent carbon dioxide, 70 percent hydrogen, and the remainder methane, carbon monoxide, nitrogen, and water. The feed gas is typically under a pressure of 125 100 psig at temperatures of 80-120°F. The carbon dioxide and water are strongly adsorbed in the adsorb beds and the residual gas stream is depressurized for further recovery. The adsorber vessel is then evacuated through vacuum blowers where the carbon dioxide, which has been adsorbed by the bed, is released at purities of essentially 99+ percent pure. 

Pressure Swing Adsorption Technology for Hydrogen Production... 

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