Patent ID: 6103143
Filing Date: 2000-08-15
Classification: B01J,C01B

Abstract:
A process for steam reforming of hydrocarbon to produce hydrogen which comprises:(a) passing a feed stream comprising steam and hydrocarbon into a first reaction zone containing particulate material consisting essentially of reforming catalyst under conditions of temperature and pressure effective to convert a portion of said steam and hydrocarbon into a gaseous mixture comprising hydrogen and carbon dioxide;(b) passing said gaseous mixture from said first reaction zone into a second reaction zone containing particulate material which consists essentially of a mixture of reforming catalyst and adsorbent capable of separating carbon dioxide by adsorption from said gaseous mixture under the conditions of temperature and pressure of step (a);(c) maintaining conditions of temperature and pressure in said second reaction zone essentially the same as in said first reaction zone, thereby further converting said steam and hydrocarbon from said first reaction zone into carbon dioxide and hydrogen and adsorbing carbon dioxide with said adsorbent;(d) withdrawing from said second reaction zone a product stream predominantly containing hydrogen and continuing steps (a) through (d) for a first time interval;(e) at the end of said first time interval simultaneously reducing the pressure in said first and second reaction zones in order to release carbon dioxide partially from said adsorbent and withdrawing carbon dioxide from said second zone in a direction countercurrent to the flow of reactants in steps (a) through (d), so that carbon dioxide passes through said first zone for a second time interval;(f) at the end of said second time interval purging said adsorbent of carbon dioxide by passing a purge gas through said second zone and into and through said first zone in a direction countercurrent to the flow of reactants and product during steps (a) through (d) for a third time interval;(g) at the end of said third time interval simultaneously repressurizing said first and second reaction zones with a nondeleterious gas to a pressure comparable to that of steps (a) through (d); and(h) at the completion of step (g) repeating at least steps (a) through (d).