Sorption Enhanced Water Gas Shift for H2 production using sour gases as feedstock

Even though hydrogen is considered the future of energy carrier, it is still produced from fossil fuels therefore with no benefits for the CO2 emission reduction. This paper discusses an innovative concept for hydrogen production which combines the Acid Gas to Syngas (AG2S™) concept and the Sorption Enhanced Water Gas Shift (SEWGS) process. The AG2S™ process produces H2 and elemental Sulfur from H2S and CO2, then H2 purification is performed through amine scrubbing. The SEWGS technology is a Pressure Swing Adsorption process where the CO2 and H2S are adsorbed on hydrotalcite-based material. With respect to amine scrubbing, SEWGS takes advantage of a higher operating temperature of 350°C–400 °C which reduces temperature swing losses, lower regeneration energy and the possibility to recycle the H2S while capturing the CO2. This study aims at exploring the potential of the SEWGS technology by means of the evaluation of detailed mass and energy balances, showing the potentialities of the AG2S™+SEWGS technologies which more than double the H2 production efficiency (25.0%) with respect to the amine scrubbing configuration (10.7%). Including the steam production, the overall process efficiency can be higher than 90% which is again more than twice the value of the AG2S™ reference case.