Comprehensive Exergy Analysis of Three IGCC Power Plant Configurations with CO2 Capture

Abstract

Abstract:We have conducted comprehensive exergy analyses of three integrated gasification combined cycle with carbon capture and storage (IGCC-CCS) power plant configurations: (1) a baseline model using Selexol™ for H 2 S/CO 2 removal; (2) a modified version that adds a H 2 -selective membrane before the Selexol™ acid gas removal system; and (3) a modified baseline version that uses a CO 2 -selective membrane before the Selexol™ acid gas removal system. While holding the coal input flow rate and the CO 2 captured flow rates constant, it was determined that the H 2 -selective membrane case had a higher net power output (584 MW) compared to the baseline (564 MW) and compared to the CO 2 -selective membrane case (550 MW). Interestingly, the CO 2 -selective membrane case destroyed the least amount of exergy within the power plant (967 MW), compared with the Baseline case (999 MW) and the H 2 -membrane case (972 MW). The main problem with the CO 2 -selective membrane case was the large amount of H 2 (48 MW worth of H 2 chemical exergy) remaining within the supercritical CO 2 that exits the power plant. Regardless of the CO 2 capture process used, the majority of the exergy destruction occurred in the gasifier (305 MW) and gas turbine (~380 MW) subsystems, suggesting that these two areas should be key areas of focus of future improvements.

Exergy Analysis of Gas Switching Chemical Looping IGCC Plants

“…A schematic of the GSOP-GSC plant is given in Figure 5: In all the models, a fixed coal input is assumed, resulting in net plant power outputs between 300 and 450 MW. This approach is consistent with other studies involving the exergy analysis of plants [17,19]. Further modeling assumptions of the power plant can be found in the Appendix A.…”

“…In the present analysis, together with the previous plant parameters, an exergy analysis is performed, introducing a rational efficiency that takes into account the fact that heat and work are not fully interchangeable. Moreover, the exergy analysis allows the identification of efficiency losses throughout all the subsections of the plant, enabling potential optimization strategies to be more effective, providing the process engineer with insights in the synthesis of alternative process line-ups and focus on items in which the greatest exergy destruction takes place, as suggested by [17].…”

“…In [17,18], an exergy analysis for IGCC plants with precombustion CO 2 capture employing different syngas shift technologies and CO 2 removal strategies is given, while [19] provides an exergy analysis of a plant employing CLC and compares it to unabated, oxyfuel, and precombustion CO 2 capture power plants. An exergy analysis of IGCC plants using CLOP to provide O 2 for post-combustion precombustion plants was performed in [20].…”

De-Capacity Policy Effect on China’s Coal Industry

“…With reference to this definition, over the years, China has strengthened coal demand-side management to improve coal utilization efficiency and thereby reduce coal demand. Specific actions or projects include: supporting and promoting emerging clean and efficient coal-fired power generation technologies such as the integrated gasification combined cycle (IGCC) [33,34], replacing direct coal burning in households with natural gas and electricity [35,36], energy-saving renovation of existing buildings [37], and technical transformation of industrial furnaces [38].…”

Exergetic Modeling of an IGCC Plant

“…With a single exception, the performance benefit of coal-CO 2 slurry was found to be outside the uncertainty range of the slurry loading, which is still one of the key unknowns of this alternative feed system. (Siefert et. al., 2016) conducted Comprehensive Exergy Analysis of Three IGCC Power Plant Configurations with CO 2 Capture.…”