| Summary: | Carbon Capture and Utilisation (CCU) is seen globally as one of the available technologies that can contribute to avoiding the effects of global warming while securing energy supply by utilising CO2 as a carbon source for chemical and fuel production. This thesis has measured the technical and economic performance of seven Carbon Capture and Utilisation (CCU) process designs (Base Case Models) based on best available technology. This was the first attempt to compare different routes of similar Technology Readiness Level to manufacture a liquid fuel from CO2. In addition, this thesis also examines the techno-economic feasibility of selective CO2 capture processes from biogas streams using ionic liquids as physical absorbents to assess the potential improvements that this developing technology could have on process performance. The selected Base Case Models were modelled using the process simulation software Aspen Plus to determine mass and energy balances. In addition, an economic assessment was developed using Aspen Plus Economic Analyzer (APEA) and MS Excel to determine capital, operating and production costs. The results revealed that the synthetic route based on CO2 capture and steam methane reforming was the most promising CO2-to-fuels route since it was able to achieve the highest overall plant energy efficiency (17.9%) and the lowest fuel production costs (£95.46 per GJ [LHV]); however this process cannot currently compete commercially with conventional fossil fuels. Further research in the specific areas suggested in this work is encouraged in order to bring fuel production costs down. It was also demonstrated that the evaluated ionic liquids cannot compete with MEA in terms of bio-methane production costs; however, the simulation methodology developed in this study can be used as a basis for further work in the area since it allows consideration of ionic liquids made of any combination of cation and anion as well as different gas streams.
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