Sorption-enhanced hydrogen production for pre-combustion CO2 capture: Thermodynamic analysis and experimental results

Hydrotalcite-based materials have been identified as suitable materials for high temperature (400 °C) adsorption of CO2. In pre-combustion decarbonisation processes for natural gas based power cycles, it should be possible to use this material to improve conversions in the water-gas shift (WGS) and steam-reforming (SMR) reaction. The efficiencies for electricity production from natural gas have been calculated for some different system configurations, in which hydrotalcite-based material could be used. The calculated efficiency penalties ranged from 5.5 to 8.6 percentage points. The assumptions made in the system study have been tested on the laboratory scale. Hydrotalcite-based materials are found to be an excellent choice for use in the sorption-enhanced WGS reactor. The requirements for very low residual concentrations of CO2 at 400 °C and large amounts of catalyst in the sorption-enhanced SMR reactor make its application less likely. Suggestions are made to how the SE-SMR could be improved.