TECHNO-ECONOMIC EVALUATION OF IGCC POWER PLANTS WITH CO_2 CAPTURE

摘要

This paper is a technical and economic comparison of the performance of four plant designs in the 500-MW output range: IGCC without CO_2 capture, IGCC with 80% capture, IGCC with CO_2 emissions equal to that of a NGCC, and IGCC with CO_2 and H_2S co-capture. The following plant performance results are discussed: net power output, efficiency, plant auxiliary energy requirements, and overall CO_2 emissions. Economic evaluations are provided. The capital investment, cost of electricity, and CO mitigation costs for all plants are detailed and compared. The results show that economics favour higher capture levels in new plants. The CO_2 mitigation costs corresponding to IGCC plants with 80 percent capture are lower than those corresponding to IGCC plants with equal emissions as NGCC plants (25 vs 26 US$/tonne CO_2 avoided). The capital cost difference (on a per kW of net installed capacity) between the above plants is 7 percent, while the CO_2 emissions of the former are almost half those of the latter. IGCC plants with CO_2 and H_2S co-capture have substantial techno-economic advantages over IGCC plants that capture CO_2 and H_2S separately. Their power output is essentially that of an IGCC without capture, with an efficiency slightly lower than that of an IGCC with similar emissions as those of a NGCC, but higher than a conventional coal-fired plant without capture. The incremental capture cost of co-capture plants is 5 percent and the electricity production cost increase is only one-third of a cent - with respect to an IGCC without capture. The CO_2 mitigation costs of co-capture plants is over four times lower than their separate-CO_2 and H_2S capture counterparts.