مشخصات پژوهش

Oxy-combustion is one of the most competitive technologies for retrofitting existing pulverized coal-fired power plants to facilitate carbon capture and sequestration processes to reduce fossil fuel-derived carbon dioxide emissions into the atmosphere. However, one of the obstacles hindering the widespread commercialization of this technology is the need to recirculate large volumes of flue gas to the boiler. Second generation atmospheric pressure oxy-combustion technologies have been developed to reduce the volume of recirculated flue gas by using high oxygen concentrations in the inlet oxidizer streams. However, recent experiments have shown that an increased ash deposition propensity is associated with these oxygen-enriched environments. This increase has been primarily attributed to aerodynamic effects, namely the higher ash concentrations associated with the reduction in flue gas volumetric flow rates and ash particle size distribution variations possibly due to a more intense combustion at the higher temperatures in the oxygen-enriched environments. Since the Stokes number and impaction efficiencies both decrease as velocity decreases for a fixed particle size, ash deposition rates under oxy-combustion conditions should be lower than those under air combustion conditions. The primary hypothesis of this thesis is that the ash particle size distribution variations is the aerodynamic effect that most influences numerical predictions of ash impaction and outside ash deposition rates.