A full-scale staged, pressurized oxy-biomass combustion towards BECCS: Performance assessment via CFD approach

Bio-energy with carbon capture and storage (BECCS) has garnered significant attention as one of the most advantageous technologies for achieving negative carbon emissions. Staged, pressurized oxy-combustion (SPOC) technology is one of the most efficient oxy-combustion technologies, which improves the net plant efficiency by controlling stoichiometric ratio to reduce the energy consumption of the flue gas recirculation unit. Staged, pressurized oxy-biomass combustion (SPOBC) is a novel and promising BECCS technology while there is little knowledge about it. This study simulates a 550 MW SPOBC boiler by ASPEN Plus and CFD model. The results show that net plant efficiency of SPOBC is higher than that of the coal SPOC boiler. NO emission of SPOBC is only 101.3 ppm. Sulfur content in biomass is 0.05 %, which is only 3.5 % of nitrogen content. Consequently, SO₂ emissions are nearly zero. This implies that energy consumption of direct contact column (DCC) in SPOBC system is reduced, leading to a significant reduction in its desulfurization and denitrification costs. CFD modeling results show that wall heat flux of SPOBC is uniform and in a safe range, suggesting that high-efficient combustion can be achieved in SPOBC boiler. This study is beneficial for achieving efficient CO₂ capture and ultra-low pollutant emissions while achieving negative carbon emissions.