Hydrogen production by absorption enhanced water gas shift (AEWGS)

摘要

AEWGS is a reaction that combines the WGS reaction and CO_2 capture by a solid absorbent to produce high purity H_2 from synthesis gas in one single step at 600-800 ℃. 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 CO_2 absorbents for this concept. AEWGS was studied using a quartz-made fixed-bed reactor at; SV= 3000 h~(-1) feed; 5% CO, 15% H_2O, balance He-N_2 at 600 ℃, 1 atm. CO_2 absorbents tested were CaO * MgO, and Na_2ZrO_3. Empty quartz-reactor tests leaded to conclude that a catalyst is needed for the WGS at temperatures of interest. A 97% H_2 product was obtained with calcined dolomite suggesting this last to act as a WGS catalyst.