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

•PSA, VSA and TSA processes were proposed, simulated and optimized for hydrogen purification.•Hydrogen purification with fuel cell specifications (purity>99.99%, CO<0.2ppm, CO2<2ppm) from syngas was the target.•The effect of overdesign of adsorbent was investigated on purity, recovery, productivity and energy consumption.•VSA and TSA can achieve pure hydrogen with fuel cell specification but VSA is more cost effective than TSA.