Comparative performance assessment of USC and IGCC power plants integrated with CO2 capture systems

In recent years coal-fired power plants have increased their role in the global energy scenario and in this framework environmental issues require a sustainable use of coal and great efforts for greenhouse gas reduction. With this aim, this paper reports on a comparative performance assessment of two power generation technologies: the Ultra Super Critical (USC) steam plant and the Integrated Gasification Combined Cycle (IGCC) plant. Performances were assessed referring to typical commercial size plants (400-500 MW) integrated with CO2 capture systems. The study is based on simulation models specifically developed through Aspen-Plus® and Gate-Cycle® software platforms. The USC plant is integrated with a SNOX section that removes simultaneously nitrogen and sulfur oxides without producing process wastes and with lower power requirements compared to traditional FGD systems. The USC plant is also integrated with a low temperature CO2 capture/compression section based on a MEA chemical absorption process. The IGCC plant is based on a Texaco entrained bed gasifier, fed by a coal-water slurry and high purity oxygen, integrated with a triple-pressure reheat combined cycle. The IGCC is integrated with a syngas cooling and treatment section composed of radiant and convective coolers, a water gas shift section and a low temperature CO 2 capture system based on a physical absorption process. The performance assessment of USC and IGCC power plants was carried out by varying the main operating parameters of both power sections and gas treatment sections. For both plants an in-depth analysis of performance penalties due to the CO2 capture systems was carried out, evaluating the influence of CO2 removal technology and efficiency