Integrated diesel fueled chemical looping combustion for power generation and CO2 capture - Performance evaluation based on exergy analysis

An integrated process for gasification of diesel and chemical looping combustion of the gasified syngas for inherent power generation and CO2 capture is developed using Aspen Plus. This system consists of four main units, including (1) gasification of diesel into syngas to ensure complete fuel conversion, (2) chemical looping combustion using an alumina supported nickel-based oxygen carrier, (3) gas turbine-based power generation and (4) steam turbine-based power generation. The model shows a high accuracy (relative error: 2.98%) which is indicated by good agreement of operating temperature, product composition and net power generation between the simulation results and data from the literature. The performance of the integrated system is evaluated based on both energy and exergy analysis approaches. In order to improve the system performance, various split ratio of (diesel) syngas to the CLC unit and to the combustion are investigated. The analysis shows that both the flow rate of oxidation air and the split ratio of syngas to the combustion unit have considerable influences on system performance while the minor effect is found in the pressure ratio. For the overall efficiency, the highest electrical efficiency is 42% and the highest exergy efficiency is 65%.