Integrated steam methane reforming process for producing carbon monoxide

A process for producing carbon monoxide which comprises the steps of:

• (a) reacting a feed stock comprising methane and water in the presence of a steam methane reforming catalyst at a temperature ranging from 700° C. to 1000° C. and a pressure ranging from 2 to 50 atmospheres to form a reformate comprising hydrogen, carbon monoxide, carbon dioxide and unreacted feedstock;
• (b) cooling the reformate to a temperature ranging from 200° to 500° C. to form a cooled reformate and dividing the cooled reformate into a first stream and a second stream;
• (c) contacting the first stream with a water gas shift catalyst under reaction conditions sufficient to form a hydrogen-enriched first stream, cooling the hydrogen-enriched first stream to form a cooled hydrogen-enriched first stream and separating the cooled hydrogen enriched first stream to form a hydrogen product stream and a hydrogen-depleted stream;
• (d) removing water from the second stream to form a water-depleted second stream and heating the water-depleted second stream to a temperature ranging from 200° to 500° C. to form a heated water-depleted second stream;
• (e) introducing the heated water-depleted second stream into a plurality of reactors operated isothermally in a predetermined timed sequence and according to the following steps which are performed in a cycle within each reactor:
• (1) reacting the heated water-depleted second stream at a first pressure in a first reactor containing an admixture of a water adsorbent and a water gas shift catalyst under reaction conditions sufficient to convert carbon dioxide and hydrogen to carbon monoxide and to adsorb water onto the adsorbent and withdrawing a CO-enriched stream under a relatively constant flow rate at the first pressure;
• (2) countercurrently depressurizing the first reactor to a second pressure by withdrawing a mixture comprising unreacted feedstock, carbon monoxide and water;
• (3) countercurrently purging the first reactor at the second pressure with a weakly adsorbing purge fluid with respect to the adsorbent wherein the weakly adsorbing purge fluid is a fluid other than a CO-enriched fluid to desorb water from the adsorbent and withdrawing a mixture comprising unreacted feedstock, carbon monoxide and water;
• (4) countercurrently purging the first reactor at the second pressure with a CO-enriched purge fluid which does not comprise hydrogen and carbon dioxide to desorb the weakly adsorbing purge fluid and withdrawing a mixture comprising the weakly adsorbing purge fluid, carbon monoxide and water;
• and
• (5) countercurrently pressurizing the first reactor from the second pressure to the first pressure with the CO-enriched purge fluid prior to commencing another process cycle within the first reactor;
• and
• (f) separating the CO-enriched stream of step c(1) to form a stream comprising CO and a CO-depleted stream, compressing the CO-depleted stream and combining the compressed CO-depleted stream with the cooled hydrogen enriched first stream of step c prior to separating the cooled hydrogen enriched first stream to form a hydrogen product stream and a hydrogen-depleted stream.