Application of elevated temperature pressure swing adsorption in hydrogen production from syngas

Abstract

A clean and energy-efficient power system can be developed by the combination of hydrogen (as an energy carrier) and fuel cells (as power generation units); such system has the potential to compete with the current energy consumption pattern of direct combustion of fossil fuels. A novel CO/CO2 purification process, called the elevated-temperature pressure swing adsorption (ET-PSA), is coupled into an integrated gasification fuel cell (IGFC) power plant system in this work. A quantitative evaluation standard for the purification energy consumption is developed by considering both the net power efficiency loss of the IGFC after introducing the purification unit, and the total CO/CO2 removal rate. The sensible heat loss of syngas and the thermal regeneration of the saturated adsorbents are avoided; consequently, the calculated energy consumption of the ET-PSA (1.11 MJ/kg) process using the ideal purification unit as the base case is 36.2% lower than of the conventional solvent absorption method. Alternatively, high-temperature steam is consumed in the ET-PSA process during the rinse and purge steps, which leads to a decrease in the output power of the steam turbine. The purification energy consumption of the ET-PSA process can be further reduced either by increasing the hydrogen recovery ratio or by reducing the total steam consumption.