Process integration of chemical looping combustion with oxygen uncoupling in a biomass-fired combined heat and power plant

Bioenergy with CO ₂ capture and storage (BECCS) has been introduced as a promising negative emission technology (NET) that opens up the possibility of producing power and heat with negative CO ₂ emissions. By combining 1.5D reactor modelling with flowsheet simulation of a complete full-scale cogeneration plant, this study assesses the applicability and potential of an advanced CO ₂ capture technology, namely chemical looping with oxygen uncoupling (CLOU), for CO ₂ capture from a biomass-fired combined heat and power (CHP) plant generating electricity, district heat (DH) at 75–90 °C supply and 45 °C return temperatures, and process steam at 10 and 4.5 bar(a) pressures. Nordic wood (50% wet-basis moisture) is used as fuel. The key performance indicators of the CLOU-integrated CHP plant were quantified and compared with those of a non-CCS reference plant. Part-load operation at reduced DH loads was considered. At 100% fuel load, the CLOU plant captured 99.0% of the CO ₂ from the combustion of biomass and still achieved a net efficiency of 80.1% _LHV, a value very close to that of the reference plant without CO ₂ capture or flue gas condensation (81.1% _LHV). Depending on the fuel load, the specific negative CO ₂ emissions from the CLOU plant ranged from 439 to 504 kg _CO2/MWh.