Oxycoal combustion is an alternative technology to the conventional coal-fired power generation, which can directly capture CO2 from coal combustion with oxygen and recycled flue gas (RFG). Compared to atmospheric oxycoal combustion, the pressurized process has advantages of increased recovery of latent heat and simultaneous NOx/SOx reduction in the flue gas condenser. Due to the increase in the particle concentration proportional to the pressure, however, the reinvention of combustion system is required to minimize the ignition delay and ash deposition while reducing the use of RFG and NOx emission. This study is to develop a design concept for the pressurized oxycoal burner to be used in a 100 kWth test facility. The computational fluid dynamics (CFD) was employed to develop and optimize the design concept by gradually changing the design variables such as the oxidant staging and burner arrangement for oxidant, fuel, and RFG. It was found that the injection of oxidant through nozzles rather than the conventional annular port of a burner is essential to achieve fast mixing and ignition in the burner due to the reduced gas velocity. Deep oxidant staging was helpful for significant suppression of fuel NOx formation. The RFG flow rate was reduced by using it for wall cooling and protection from ash deposition while the pure oxygen was mixed directly with coal for fast ignition and char conversion in a high-temperature flame.
1. 서 론
2. 해석 대상 및 적용 모델
3. 해석 결과
4. 결 론