Edward Landis Weist

Chapter 13 – Development of the Sorption Enhanced Water Gas Shift Process

This chapter presents the development of a novel precombustion decarbonization technology referred to as the sorption enhanced water gas shift (SEWGS) process. This development program was supported through the precombustion subgroup of the CO 2 Capture Project (CCP). This technology is particularly attractive for decarbonizing gas turbine fuel, and hence provides opportunities for power generation with minimal CO 2 emissions, high power efficiency and potentially lower cost of capturing CO 2 for storage. The SEWGS process simultaneously converts syngas containing CO into H 2 and CO 2 and removes the CO 2 from the product hydrogen by adsorption. The system operates as a multi-bed pressure swing adsorption unit, with each bed packed with a mixture of shift catalyst and a high-temperature CO 2 adsorbent. Carbon in the feed gas in the form of CO and CO 2 are removed from the product gas by the CO 2 adsorbent, and after specific PSA process steps, rejected as relatively high-purity CO 2 for recovery. The product hydrogen produced during the feed step contains the excess steam from the reaction and any nitrogen from the syngas generation, and is at high temperature and feed pressure. This hot fuel mixture can be burned in gas turbines with higher turbine efficiency than with natural gas firing and substantially lower NO x formation.

Development of a process for CO2 capture from gas turbines using a sorption enhanced water gas shift reactor system

Publisher Summary This chapter evaluates the performance of the K 2 CO 3 /I-ITC adsorbent (HTC) in the process test unit. The temperature dependence of the CO 2 capacities is characterized by a 10kcal/mole heat of adsorption. The CO 2 adsorption and desorption processes were evaluated in a fixed bed system and the data were used as basis for sorption enhanced water gas shift (SEWGS) process designs. The SEWGS concept was demonstrated with a vessel packed with hydrotalcite (HTC) and temperature shift reactor (HTS) catalyst. With no adsorbent, CO and CO 2 breakthrough once the void gases are displaced. When adsorbent is added, the CO 2 breakthrough is delayed, and the removal of CO 2 drives the CO to insignificant levels. Decarbonized product gas containing feed He and N 2 and additional H 2 formed via the reaction is produced at reaction pressure and temperature. A cyclic experiment was conducted which demonstrated that a stable product gas can be formed with 5 times less CO+CO 2 than in the feed. Power generation process designs have been generated for the CCP Norcap scenario utilizing SEWGS fuel gas decarbonization. The SEWGS processes use hydrotalcite as a high temperature CO 2 adsorbent. Economic evaluations indicate that this approach has potential for clean power production with CO 2 recovery for sequestration.