Abstract:

Chemical looping combustion (CLC) offers a possibility of separating the greenhouse gas CO₂.An integrated gasification combined cycle based on CLC is discussed in this paper.In the system,NiO/NiAl₂O₄ is used as the CLC oxygen carrier and Texaco gasification process is selected.The system performance is simulated by using ASPEN software tool.The system efficiency is 39.61%HHV (41.55%LHV) and CO₂ emission is 126 g·kW^-1·h^-1, assuming compressor pressure ratio 17, air reactor outlet temperature 1200℃, turbine inlet temperature (TIT) 1350℃ after supplementary firing, and cooling air fraction 12%.At TIT 1350℃, CO₂ capture rate increases by about 23% and system efficiency decreases from 40.3% to 39.61% when the air reactor outlet temperature rises from 1000℃ to 1200℃.With the increase of TIT after supplementary firing from 1200℃ to 1500℃, system efficiency increases from 37.4% to 40.8% and CO₂ emission rises from 3 g·kW^-1·h^-1 to 202 g·kW^-1·h¹.At a specific TIT there exits an optimum pressure ratio and the optimum pressure ratio goes up as TIT rises.