CO2-selective membrane reactor process for water-gas-shift reaction with CO2 capture in a coal-based IGCC power plant

Abstract

Integrated gasification combined cycle (IGCC) power plants enable pre-combustion carbon capture to reduce CO₂ emissions. Membrane water-gas-shift (WGS) reactors can intensify these processes by converting raw syngas to H₂ with simultaneous CO₂ capture in one unit. This paper reports process design and techno-economic analysis (TEA) for a membrane reactor (MR) process with a CO₂ selective ceramic-carbonate dual-phase (CCDP) membrane for WGS reaction with CO₂ capture for a IGCC power plant. The target performance includes CO conversion > 95 %, hydrogen purity > 90 %, CO₂ purity > 95 %, and carbon capture > 90 %. Using a commercial catalyst and a CCDP membrane, the MR can achieve the performance target at 750 °C and space velocity of 250 h⁻¹. The outcome of the process design and TEA shows that the CCDP MR has an operating cost of $24 M/year, significantly lower than that for the conventional processes (40 M$/year). However, the MR process has a higher capital cost ($1007 M) than the conventional process ($527 M) because of the higher cost of the CCDP MRs. Modeling analysis shows a MR with higher CO₂ permeance can deliver the target at a higher space velocity and lower membrane surface area to catalyst volume ratio, leading to a significantly reduced MR capital costs.