Thermodynamic System Evaluation of an IGCC Plant Using Pre-Combustion CO2 Capture with SEWGS Technology

An Integrated gasification combined cycle (IGCC) plant with pre-combustion carbon capture is proposed as an alternative to meet the high demand of clean, reliable power. Flexibility in such plants could be introduced with polygeneration schemes. This paper focuses on system studies on coal-fired IGCC plants with carbon capture but no polygeneration. A comparative study is presented between three IGCC models one with carbon capture (using SELEXOL), one base case without any carbon separation and an IGCC model with the sorption enhanced water gas shift (SEWGS) cycle for the carbon separation. The SEWGS technology is based on adsorption for the carbon separation. In addition, a preliminary evaluation of the polygeneration options is presented. A brief outlook on system comparison to high-efficiency systems like fuel cell (SOFC) integrated plants is also given. The base case model without carbon capture gives a net plant efficiency of 46.6%. The SHELL gasifier cold gas efficiency is about 82%. For the IGCC model with carbon capture using SELEXOL, a net plant efficiency of 38.5% was achieved with a gasifier efficiency of 81.2%. CO2 capture efficiency from the process is about 91%. The model with the SEWGS unit for carbon capture gives a slight improvement in the net efficiency of the plant by approximately 2% as compared to the one with the SELEXOL unit.