Investigating PSA, VSA, and TSA methods in SMR unit of refineries for hydrogen production with fuel cell specification

Abstract

Abstract In this paper a robust and reliable process is proposed for purification of hydrogen from syngas to approach to the specification of fuel cell application (H2 purity >99.99, CO impurity 99.99%) and minimum CO content of 0.2 ppm, with appropriate recovery and productivity. Among the studied processes, PSA re-pressurized with feed had limited ability to achieve fuel cell hydrogen specification whereas PSA re-pressurized with product could achieve these specifications; however the low recovery of the process made it unreliable from economical point of view. Considering high H2 purity and acceptable recovery, TSA would be the appropriate process, but its low productivity is a great imperfection. Considering the purity of hydrogen, energy consumption and capital cost, VSA would be the most superior process compared with the other cyclic processes. At the optimal point of view, for a feed with 75mol% H2, VSA has resulted productivity of 148 mol H2/(kgads⋅day) with 940 kJ/kgH2product electrical energy consumption whereas TSA has resulted only 86 mol H2/(kgads day) productivity, with 420 kJ/kgH2product, electrical energy and 45.2 MJ/kgH2product heating energy consumption.