Patent ID: 7618478
Filing Date: 2009-11-17
Classification: B01D,C01B,Y02C,Y02P

Abstract:
1. A vacuum pressure swing adsorption (VPSA) process for the recovery of carbon dioxide from a multi-component gas mixture containing at least carbon dioxide and hydrogen in a VPSA unit containing at least one adsorption bed containing at least one CO 2 -selective adsorbent, the process comprising: feeding the multi-component gas mixture containing the at least carbon dioxide and the hydrogen to the at least one adsorption bed at a first pressure within a first pressure range for a predetermined time to produce a hydrogen-enriched stream; depressurizing the at least one adsorption bed in a first depressurization step from the first pressure to a second pressure within a second pressure range in a same direction as or an opposite direction as the feed flow; depressurizing the at least one adsorption bed in a second depressurization step from the second pressure to a third pressure within a third pressure range in a same direction as or an opposite direction as the feed flow; depressurizing the at least one adsorption bed in a third depressurization step from the third pressure to a fourth pressure within a fourth pressure range in a same direction as or an opposite direction as the feed flow; depressurizing the at least one adsorption bed in a final depressurization step from the fourth pressure to a pressure range close to ambient in a same direction as the feed flow or in a direction opposite the feed flow to produce at least a first portion of CO evacuating the at least one adsorption bed from the pressure close to ambient to a pressure at or below ambient in a direction opposite the feed flow to produce at least a second portion of CO pressure equalizing the at least one adsorption bed in a first pressure equalization step in a direction opposite the feed flow; further pressure equalizing the at least one adsorption bed in a second pressure equalization step in a direction opposite the feed flow; further pressure equalizing the at least one adsorption bed in a third pressure equalization step in a direction opposite the feed flow; and repressurizing the at least one adsorption bed in a repressurization step to the first pressure range; wherein the process is repeated cyclically.