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

Abstract

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 CO2 Capture Project (CCP). This technology is particularly attractive for decarbonizing gas turbine fuel, and hence provides opportunities for power generation with minimal CO2 emissions, high power efficiency and potentially lower cost of capturing CO2 for storage. The SEWGS process simultaneously converts syngas containing CO into H2 and CO2 and removes the CO2 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 CO2 adsorbent. Carbon in the feed gas in the form of CO and CO2 are removed from the product gas by the CO2 adsorbent, and after specific PSA process steps, rejected as relatively high-purity CO2 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 NOx formation.