Processes with Reduced Primary Reformer Firing

Processes with Reduced Primary Reformer Firing 

In the Canadian plant, only the air compressor is driven by a steam turbine, which receives the total steam generated in the plant and has an electric generator on the same shaft. All other consumers, including synthesis gas compressor, are driven by electric motors. Separate machines are used for makeup gas and recycle compression. The makeup gas compressor is located upstream of the methanator to make use of the compression heat to warm up the cold gas coming from the Selexol carbon dioxide scrubber. 

Montedison Low-Pressure Process. The Montedison low-pressure process [940], [1036], [1128], [1129] involves a split flow to two primary reformers. About 65% of the feed-steam mixture flows conventionally through the radiant tubes of a fired primary reformer followed by a secondary reformer. The balance of the feed-steam mixture passes through the tubes of a vertical exchanger reformer. This exchanger reformer has a tube sheet for the catalyst tubes at the mixed feed inlet. There is no tube sheet at the bottom of the tubes, where the reformed gas mixes directly with the secondary reformer effluent. The combined streams flow on the shell side to heat the reformer tubes in a manner similar to that described for the M. W. Kellogg KRES reformer, see Sections 4.1.1.8 and 5.1.4.3). The process air flow is stoichiometric. Synthesis is performed at 60 bar in a proprietary three-bed indirectly cooled converter with am- 

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Processes with reduced primary reformer firing and surplus process air... 

Processes with Reduced Primary Reformer Firing... 

If the secondary reformer is operated with an excess of process air (about 50% above the stoichiometric amount), or if the process air is enriched to an Oj-content of about 30%, then the sensible heat in the product gas from the secondary reformer is sufficient for the primary conversion of natural gas in a heat exchange reformer, meaning that the fired reformer can be eliminated. Such schemes require, however, extra installations, either for production of enriched air or for removal of excess N2 from the synthesis gas, and they suffer of course also from the reduced efficiency of the steam production described above. 

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