Research progress on biomass oxy-fuel combustion technology

Bio-Energy Carbon Capture Utilization and Storage （BECCUS） has been proposed as a negative carbon technology, which combines the biomass combustion with CCUS techniques to achieve rapid, large-scale, and sustainable CO₂ reduction. Biomass oxy-fuel combustion technology replaces the fuel in oxy-fuel combustion with a mixture of biomass and coal or pure biomass, and adopts high-purity oxygen and recirculated flue gas as the oxidizer, so that it can achieve high CO₂ concentration in the flue gas. Compared with conventional pulverized coal oxy-fuel combustion and biomass air combustion, due to significant changes in fuel and combustion atmosphere, the furnace temperature and heat flux, pollutant emissions, heating surface issues, CO₂ capture efficiency, and power plant efficiency in biomass oxy-fuel combustion also undergo noticeable changes. In this regard, based on previous research, this article systematically reviews the latest research progress in biomass oxy-fuel combustion technology, summarizes the combustion characteristics and pollutant formation mechanisms of biomass oxy-fuel combustion: the reaction kinetics parameters of biomass oxy-fuel combustion remain largely consistent under both air- and oxy-fuel atmospheres; the gasification reactions of biomass char with CO₂ and H₂O help reduce NO_x formation and promote coal char burnout, generating more fine particulate matter; the initial oxygen concentration required for biomass oxy-fuel combustion to match air combustion exceeds 30%. The article also points out the challenges faced by biomass oxy-fuel combustion, such as fuel instability, high costs, heating surface corrosion, and pollutant formation. To address these issues, it proposes researching the synergistic effects of co-firing multiple biomass types on combustion characteristics （i.e., ignition, burnout） and pollutants formation （i.e., NO_x, SO₂, HCl）, forming new insights to enhance combustion and suppress pollutant generation; optimizing operational parameters of biomass oxy-fuel combustion and regulating furnace temperature to mitigate ash deposition, slagging, and corrosion; adopting emerging technologies such as pressurized oxy-fuel combustion and pressurized circulating fluidized bed oxy-fuel combustion to improve combustion efficiency and reduce pollutant emissions; and designing new multi-generation processes for electricity-heat-gas production based on biomass oxy-fuel combustion to achieve autonomous regulation of multi-objective products and adapt to diverse application scenarios. Ultimately, this provides a theoretical basis and important reference for achieving low-carbon and clean combustion of biomass