초록 ▼

One portion comprising about 30-80% of a hydrogen-containing feed gas having a relatively high carbon dioxide content is preheated to remove a substantial portion of said carbon dioxide therefrom. The thus - preheated stream is passed to a pressure swing adsorption bed from which a purified hydrogen

One portion comprising about 30-80% of a hydrogen-containing feed gas having a relatively high carbon dioxide content is preheated to remove a substantial portion of said carbon dioxide therefrom. The thus - preheated stream is passed to a pressure swing adsorption bed from which a purified hydrogen stream is withdrawn. Upon completion of this step, the unpretreated portion of the feed gas is passed to the feed end of the bed, with purified hydrogen continuing to be withdrawn from the bed. In cyclic pressure swing adsorption operations employing such a two-feed process, the recovery of purified hydrogen is enhanced as compared with operations in which none of the feed gas is pretreated for carbon dioxide removal or in which all of the feed gas is so treated for removal of carbon dioxide therefrom.

대표청구항 ▼

An improved pressure swing adsorption process for the separation and purification of hydrogen contained in a gas stream having a relatively high concentration of carbon dioxide therein comprising: (a) pretreating at least about 30% up to about 80% by volume of said gas stream to remove a substantial

An improved pressure swing adsorption process for the separation and purification of hydrogen contained in a gas stream having a relatively high concentration of carbon dioxide therein comprising: (a) pretreating at least about 30% up to about 80% by volume of said gas stream to remove a substantial portion of said carbon dioxide therefrom, the unpretreated gas stream having a carbon dioxide content of at least about twice that of the thus-pretreated gas stream; (b) passing the pretreated gas stream at an elevated adsorption pressure to the feed end of an adsorbent bed capable of adsorbing carbon dioxide and other impurities of said stream, a purified hydrogen stream being withdrawn from the product end of the bed having an advancing adsorption front therein; (c) upon completion of step (b), passing the unpretreated gas stream to said feed end of the bed at essentially the same pressure as in step (b), a second adsorption front being created at the higher concentration and adsorption loading of carbon dioxide, a purified hydrogen stream continuing to be withdrawn from the product end of the bed; (d) concurrently depressurizing said bed to release void space gas from the product end of the bed; (e) countercurrently depressurizing said bed to a lower desorption pressure to desorb and release carbon dioxide and other impurities from the feed end of the bed; (f) repressurizing said bed to said elevated adsorption pressure; and (g) repeating said steps (b)-(f) for the separation and purification of additional quantities of hydrogen; whereby the recovery of purified hydrogen is enhanced at a significant savings in equipment and operating costs as compared with the pretreatment of all of the gas stream for removal of carbon dioxide therefrom.