Sign up for email alert when new content gets added: Sign up
Liutao Sun
Harbin Institute of Technology, China
ScientificTracks Abstracts: Curr Res Integr Med
Statement of the Problem: Semicoke, a solid byproduct from low-temperature pyrolysis of low-rank coal, is characterized by an ultralow volatile content (less than 10%) and a high calorific value, which always causes high NO emissions, poor flame stability and low char burnout when burned at a relatively high temperature. Hence, co-combustion with high-volatile bituminous coal is a feasible approach. However, the optimal semicoke blending ratio is limited to within 45% ~ 50%, which is usually not sufficient for the large-scale utilization of semicoke in power plants. The implementation of semicoke co-combustion by a larger proportion still faces many challenges, such as poor performances in ignition and pollution emissions. To stabilize semicoke co-combustion, bluff-body burners have been adopted to stabilize flames to promote ignition and reduce the unburned carbon content in fly ash and NOx emissions. Methodology & Theoretical Orientation: A numerical study using computational fluid dynamics (CFD) was utilized during semicoke co-combustion under various bluff body cone angles (α). Damkhöler numbers (Da) for homogeneous and heterogeneous reaction was utilized to elaborate the microscopic characteristic of co-combustion. Findings: With increasing α the main reaction zone moves upstream significantly, and a widened flame and uniform temperature profile are obtained due to enhancing the internal flue gas recirculation. The maximum homogeneous Da values are below 0.50, and the heterogeneous Da values of C-O2, C-CO2, and C-H2O are within 0.670-1.207, 0.004-0.017 and 0.001-0.004, indicating that the char oxidation reaction is dominated by diffusion/kinetics, while the char gasification reactions are controlled by chemical kinetics. However, both reactions tend to be kinetically-controlled with increasing α. Conclusion & Significance: Based on comprehensive analyses of the simulations, we can gain deep insight into turbulencechemistry interaction behaviors and NOx formation affected by the cone angle cases, further uncovering the underlying control mechanisms on low-NOx emissions in large-scale semicoke co-combustion.
Sun has his expertise in improving the semicoke blended combustion and air/oxy-MILD semicoke combustion. His findings can provide deep insight into the turbulence-chemistry interactions and its effect on NOx emission characteristics of semicoke co-combustion in a bluff-body tangential burner and can guide the boiler operation. This approach is responsive to all stakeholders and has a different way of focusing.
+44-7723-59-8358
