Hydrogen production by absorption enhanced water gas shift (AEWGS)

AEWGS is a reaction that combines the WGS reaction and CO2 capture by a solid absorbent to produce high purity H2 from synthesis gas in one single step at 600–800 °C. This reactor system, if homogeneous, would not require a catalyst. However, previous research on this concept was not conclusive, since a steel reactor was used and reactor walls were suspected to act as catalyst. Therefore, there is a need to address this issue and to select and evaluate suitable CO2 absorbents for this concept. AEWGS was studied using a quartz-made fixed-bed reactor at; SV = 3000 h−1, feed; 5% CO, 15% H2O, balance He–N2 at 600 °C, 1 atm. CO2 absorbents tested were CaO*MgO, and Na2ZrO3. Empty quartz-reactor tests leaded to conclude that a catalyst is needed for the WGS at temperatures of interest. A 97% H2 product was obtained with calcined dolomite suggesting this last to act as a WGS catalyst.