Reformer-pressure swing adsorption process for the production of carbon monoxide

An improved process for the production of carbon monoxide by the steam reforming of hydrocarbons comprising:

• (a) catalytically reacting a fluid hydrocarbon feed stream with steam in a steam reformer;
• (b) passing the reformer effluent containing hydrogen, carbon monoxide and carbon dioxide from said steam reformer, without scrubbing to remove the carbon dioxide content thereof, to a pressure swing adsorption system having at least four adsorbent beds, each bed of which, on a cyclic basis, undergoes a processing sequence comprising:
• (1) introducing the reformer effluent to the feed end of the adsorbent bed at a higher adsorption pressure, with a hydrogen-rich gas being discharged from the product end of the bed as the less readily adsorbable component thereof, and with a leading adsorption front of said carbon monoxide as the intermediate component being established in the bed ahead of a trailing adsorption front of said carbon dioxide as the more readily adsorbable component of said effluent gas;
• (2) introducing to the feed end of the bed a displacement gas essentially free of hydrogen, the molar concentration of the carbon monoxide and/or carbon dioxide components being greater in said displacement gas than in the reformer effluent passed to the bed, said gas being introduced such that the less readily adsorbable hydrogen component is essentially completely displaced from the bed prior to initiation of intermediate carbon monoxide component recovery;
• (3) cocurrently depressurizing said bed with discharge of said carbon monoxide intermediate component from the product and thereof as a desired product;
• (4) countercurrently depressurizing and/or purging the bed to remove a carbon dioxide-rich more readily adsorbable component stream therefrom;
• and
• (5) repressurizing said bed to the higher adsorption pressure;
• (c) recycling said carbon dioxide-rich stream to said steam reformer for reaction with additional quantities of the hydrocarbon feed stream being passed to the stream reformer to form additional quantities of carbon monoxide and hydrogen, with product recovery being enhanced and the need for employing a carbon dioxide wash system being obviated.