Feasibility study of implementing chemical looping combustion with BECCS: Process modeling and techno-economic analysis of a CHP plant at Skövde Energi

Examensarbete för masterexamen
Master's Thesis
Innovative and sustainable chemical engineering (MPISC), MSc
Fortet Casabella, Judit
Chehade, Yunes
Climate change is an urgent worldwide issue that is mostly brought on by the accumulation of greenhouse gases, including CO2 in the atmosphere. Carbon Capture and Storage (CCS) technologies can play an important role in the decarbonization process. Chemical Looping Combustion (CLC) using biomass as a fuel can be combined with CCS to obtain negative emissions. This work is part of a collaboration between Chalmers University of Technology and Skövde Energi. The project includes performing a process modeling and techno-economic assessment of substituting one of the existing biomass CHP-plant boilers with a CLC-system; including the capture, compression, and liquefaction of the CO2 obtained. The general objective is to analyze the techno-economic feasibility of the CLC technology and give some guidelines for future implementation at Skövde Energi’s site. Additionally, the technology is compared with a post-combustion study using absorption with monoethanolamine (MEA), previously performed for the same combustion unit. After an initial review of the main literature and assessment of the current boiler operation, a base case simulation of the full-chain process is performed in Aspen Plus, including gas conditioning and liquefaction of the CO2. The process model considered heat integration of the different components together with the steam cycle for electricity production. Furthermore, a design of the fluidized bed CLC unit was conducted as well as a techno-economic analysis of the full-chain process, which was compared to the use of a post-combustion technology. Finally, through the interpretation of the obtained results, a discussion is performed on how the implementation of the technology would affect the current production and future considerations for implementation at other sites. The work concludes that the CLC technology would lead to a total capture efficiency of 97.5 %, capturing around 101 ktonne CO2 and obtaining a capture cost of around 800 SEK/tonne CO2 captured, which includes the purchase and installation of equipment. This is considerably lower than what is expected in a post-combustion system, with costs of about 1,100 SEK/tonne CO2 captured. The reason for this is due to the lower amount of energy and equipment needed for the capture process. Excluding installation costs, a capture cost of around 330 SEK/tonne CO2 captured was obtained, which is slightly higher than the 200 SEK/tonne CO2 of a 1000 MWth design by Leckner and Lyngfelt.
carbon capture and storage (CCS) , chemical looping combustion (CLC) , negative emissions , combined heat and power plant (CHP-plant)
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