A technical and economic assessment of carbon dioxide capture technology for IGCC power plants

This thesis develops a general modeling framework to provide tools for assessing gasification-based energy conversion systems with various CO 2 capture options on a systematic and consistent basis.; Simulation studies of an oxygen-blown Texaco quench gasifier system with a water gas shift (WGS) reactor and Selexol CO2 capture unit indicated that the CO2 avoidance cost is lowest when the CO2 removal efficiency is in the range of 85%-90%. The overall cost of IGCC systems with and without CO2 and storage varied significantly with coal quality and plant size. For low rank coals (sub-bituminous and lignite) costs increased significantly relative to the nominal case with bituminous coal. It was also found that larger IGCC plants have slightly higher thermal efficiency and lower capital cost. Without incentive financing, however, an IGCC power plant without CO2 capture was found to be less competitive (more costly) than PC and NGCC power plants in terms of both the total capital requirement and cost of electricity production. However, IGCC plants with CO2 capture were competitive with PC and NGCC capture plants without incentive financing.; This thesis also provides an overview of available options and decisions factors for using IGCC technology to repower aging PC power plants. Studies in this thesis show that IGCC repowering is less capital intensive than greenfield plants, but the feasibility of repowering is very site-specific.; This thesis also attempts to characterize key uncertainties affecting the performance and cost of IGCC systems with CO2 capture through data mining and Monte Carlo simulation. Most of the capital cost uncertainty in an IGCC capture plant comes from the IGCC process, rather than the CO 2 capture process. Considering the historical variability of capacity factor and coal price for large U.S. coal plants, the COE of an IGCC capture plant may be higher than the expected value based on typical deterministic assumptions.; This thesis also presents preliminary evaluations of IGCC systems using two advanced technologies, the Ion Transport Membrane system for oxygen production and the GE H-class turbine for power generation. Study results show that these two technologies can significantly improve the competitiveness of IGCC and will influence the application of IGCC in the near future.