Efficient pressure swing adsorption for improving H2 recovery in precombustion CO2 capture

Abstract

An efficient design for pressure swing adsorption (PSA) operations is introduced for CO2 capture in the pre-combustion process to improve H2 recovery and CO2 purity at a low energy consumption. The proposed PSA sequence increases the H2 recovery by introducing a purge step which uses a recycle of CO2-rich stream and a pressure equalizing step. The H2 recovery from the syngas can be increased over 98% by providing a sufficient purge flow of 48.8% of the initial syngas feeding rate. The bed size (375m3/(kmol CO2/s)) and the energy consumption for the compression of recycled CO2-rich gas (6 kW/(mol CO2/s)) are much smaller than those of other PSA processes that have a CO2 compression system to increase the product purity and recovery.