Techno-Economic Assessment of Integrated Chemical Looping Air Separation for Oxy-Fuel Combustion: An Australian Case Study

摘要

A techno-economic analysis was carried out to assess the oxy-fuel conversion of eight major coal-fired power plants in the state of NSW, Australia. For this purpose, several alternative retrofit configurations, differing only in the air separation unit (ASU) but otherwise identical, were considered. More specifically, three types of oxygen plants were studied: a cryogenic-based air separation unit and integrated chemical looping air separation units using steam (ICLAS[S]) and recycled flue gas (ICLAS[FG]) as the reduction medium. The main objective of the techno-economic analysis was to determine if the economic viability of oxy-fuel operations could be enhanced by incorporating ICLAS technology. The results show that the normalized oxygen demand for the NSW fleet of coal-fired power plants was about 450550 m(3)/MWh, with Bayswater having the lowest normalized oxygen demand and Munmorah having the highest one. Moreover, it was found that by replacing a cryogenic-based ASU with an ICLAS unit, the average reduction in the ASU power demand was up to 47% and 76%, respectively, for ICLAS[S] and ICLAS[FG]. Similarly, the average thermal efficiency penalty associated with the cryogenic and the ICLAS[S] and ICLAS[FG] units was found to be about 9.5%, 7.5%, and 5%, respectively, indicating that the ICLAS[FG] unit is the most energy efficient option for oxy-fuel plants. Economic analyses suggest that a retrofit cost reduction of about 32% can be achieved by incorporating an ICLAS[FG] unit. On average, the levelized cost of electricity associated with the cryogenic and the ICLAS[S] and ICLAS[FG] units for the NSW fleet of coal-fired power plants was found to be about $118/MWh, $105/MWh, and $95/MWh, respectively.