US Patent 8187363 PSA tail gas preheating

A process for improving the thermodynamic efficiency of a hydrogen generation system is provided. This includes producing a syngas stream in a reformer, wherein the reformer has a combustion zone. This also includes introducing a syngas stream into a pressure swing adsorption unit, thereby producing a product hydrogen stream and a tail gas stream. This also includes heating the tail gas stream by indirect heat exchange with a heat source, thereby producing a heated tail gas stream; and introducing the heated tail gas stream into the combustion zone.