Improved sorbent for the sorption-enhanced water-gas shift process

AbstractFor the sorption-enhanced water-gas shift (SEWGS) process, a new sorbent material has been developed. The sorbent is a potassium-carbonate promoted hydrotalcite-based material. The material has been tested under realistic process conditions in an experimental rig of 2 m length. The cyclic capacity of the material is 27% higher than the cyclic capacity of the reference sorbent, which was used in CACHET, a previous R&D project. Moreover, 36% less steam is required for its regeneration. The sorbent pellets also have a 65% higher crush strength than the reference sorbent. Contrary to the reference material, the novel material does not form notable amounts of MgCO3 under relevant operating conditions. Due to the absence of this slow CO2 uptake process, the sorbent remains mechanically stable, the cyclic steady state is reached rapidly, CO2 slip in the product gas is reduced, and steam requirements are lowered. It is demonstrated that the sorbent remains mechanically stable during operation of at least 1200 adsorption–desorption cycles. With this new, higher density material, carbon capture levels exceeding 95% can be obtained more efficiently and vessels will be smaller