RESUMO

The objective of the article is to show that a novel integrated gasification combined cycle (IGCC) plant based on an oxyfuel Matiant combined cycle is a possible alternative to a standard IGCC with precombustion capture, from the performance viewpoint. From recent studies on new IGCC plants ranging in size from 350 to 800 MWe and using commercially available physical absorption systems, the average values of energy penalties are around 15% and of CO₂ capture rates within 80−90% per kWh generated. The proposed oxyfuel IGCC is a combination of an O₂−CO₂ gas turbine power cycle with reheat and a steam cycle with two pressure levels and a reheat in the heat recovery steam generator. It takes advantage of the already existing air separation unit in a conventional IGCC, which has now to be sized to produce the total amount of O₂ required, which is about 2.5 times more than in the conventional IGCC. All in all, the performance of the oxyfuel IGCC is slightly higher than that of an IGCC with precombustion capture, but now the CO₂ retention rate is nearly 100%, instead of 90%. However, the turbo-machines operating on CO₂-water mixtures are not currently available and require a totally new design. In this article, a sensitivity analysis on the basic parameters is carried out, and the best configuration is derived from the discussion of the results.