Microwave assisted in-situ gasification chemical looping combustion of coal using different oxygen carrier integrated with chemical production unit

Abstract

Chemical looping combustion (CLC) is a promising technology for the clean and efficient production of energy without carbon emissions in the atmosphere. CLC uses two reactors, a fuel reactor and an air reactor, to combust fuel with the help of oxygen carriers (OC) such as NiO, Fe₂O₃, etc. In-situ gasification based CLC needs to be integrated with microwave for fast and energy efficient process. In the current study, the microwave assisted chemical looping combustion (MW-CLC) of coal is investigated using NiO, CuO and Fe₂O₃. Further, the MW-CLC process is simulated using Aspen Plus for dimethyl carbonate (DMC) production and a techno-economic analysis is performed to determine the feasibility of the process. The experimental results show the production of an average percentage of CO₂ of 97 vol.% for CuO, 92 vol.% for NiO and 91 vol.% for Fe₂O₃ during the MW-CLC. Further, the post MW-CLC residue analysis confirms the reduction of the OC to their respective metals i.e., Ni (79.9 wt.%), Cu (78.5 wt.%) and Fe (80.4 wt.%). The integration of the MW-CLC process ensures the production of 51.21 g/s of DMC and 142–215 kW of electricity from the proposed plants. This results in the maximum net energy efficiency of 46.47% and the lowest cost of electricity of 68.19 $/MWh for NiO as the OC. The cost of methanol and DMC production is found in between 0.62–0.89 $/kg and 0.95–1.38 $/kg, respectively.