Carbon Capture and Storage (CCS) is a key technology to achieve greenhouse gas emission reduction targets and mitigate global warming. CO2 capture is the building block of CCS with considerable impact on the downstream transportation and storage stages.
Chemical looping combustion (CLC) is an innovative combustion technology with inherent CO2 separation. A metal oxide is used to transfer oxygen from the air reactor to the fuel reactor, where fuel is burned without direct contact with air. The resulting CO2 from the combustion part of the process is not diluted with nitrogen from the air, hence, no additional CO2 separation step is required. This is the main feature of the CLC process, which permits inherent CO2 separation with a high degree of energy efficiency improvement and competitive capture cost.
Captured CO2 must satisfy specifications depending on its form of transport and final destination, which may be storage or utilisation. This means that, due to downstream requirements, treatment and conditioning are critical steps in the CO2 capture process.
Various contaminants may be present in the captured stream, such as NOx and SOx, depending on the type and quality of the fuel. Fuels such as natural gas and some biomass feedstocks need little post treatment while heavy fuels, such as petcoke, need NOx and SOx removal units. These technologies are currently deployed at large scale in industrial applications. However, CO2 captured in a CLC plant has some differences compared to conventional flue gasses, such as absence of free N2, lack of or low O2 content and high steam concentration. This makes the flue gas from a CLC plant lower in volume but higher in concentration of contaminants, which results in some specific challenges to be overcome.
TOTAL has launched a development and engineering feasibility study together with HAMON on the CO2 treatment topic. HAMON is a technology provider on flue gas treatment with extensive experience on industries such as power, refining and petrochemicals. This study is focussed on the treatment of CO2 captured from a petcoke-fired CLC plant. Regarding the typical content of this fuel, a complete flue gas treatment scheme is needed including dust particle removal, DeNOx and DeSOx. This will be further completed by drying and compression steps to deliver a CO2 that is compliant with specifications for CO2-EOR usage.
CHEERS project aims at demonstration of CLC technology at 3 MWth scale including feasibility and techno-economic studies for preparation of industrial demonstration. This study permits evaluation of the next CLC development phase, which will be an industrial demonstration unit at a capacity of 30 – 60 MWth. The aim is that success at this stage will result in wide industrial deployment of the CLC technology to produce steam for industrial applications or electrical power with zero or negative CO2 emission and improved energy efficiency. The CHEERS consortium includes Bellona, Dongfang Boiler Group Co. Ltd (DBC), IFP Energies nouvelles (IFPEN), SINTEF Energy Research, SINTEF Industry, TOTAL, Tsinghua University, Silesian University and Zhejiang University.
The CHEERS project is financed partially by the EU’s Horizon 2020 Research and Innovation Programme and the Chinese Ministry of Science and Technology, with financial and industrial support from project partners.