More Energy-Efficient CO2 Capture from IGCC GE Flue Gases

Abstract

Carbon dioxide (CO2) emissions are one of the main reasons for the increase in greenhouse gasses in the earth’s atmosphere and carbon capture and sequestration (CCS) is known as an effective method to reduce CO2 emissions on a larger scale, such as for fossil energy utilization systems. In this paper, the feasibility of capturing CO2 using cryogenic liquefaction and improving the capture rate by expansion will be discussed. The main aim was to design an energy-saving scheme for an IGCC (integrated gasification combined cycle) power plant with CO2 cryogenic liquefaction capture. The experimental results provided by the authors, using the feed gas specification of a 740 MW IGCC General Electric (GE) combustion power plant, demonstrated that using an orifice for further expanding the vent gas after cryogenic capture from 57 bar to 24 bar gave an experimentally observed capture rate up to 65%. The energy-saving scheme can improve the overall CO2 capture rate, and hence save energy. The capture process has also been simulated using Aspen HYSYS simulation software to evaluate its energy penalty. The results show that a 92% overall capture rate can be achieved by using an orifice.

Keywords

• IGCC GE process gases
• expansion
• cryogenic separation
• process system modeling