Numerical analysis and modified thermodynamic calculation methods for the furnace in the 1000 MW supercritical CO_2 coal-fired boiler

摘要

Supercritical carbon dioxide (S-CO_2) coal-fired power generation technology is considered as the transformative technology in the energy sector due to its high efficiency, simple turbomachinery and high power density though the concept design of S-CO_2 boiler is still in the infancy stage. This study constructs a modified combustion and heat transfer thermodynamic calculation method of the S-CO_2 boiler adapted for multi-zone furnace. The effects of parameters and configurations on the characteristics of the S-CO_2 boiler are compared and analyzed. The results show that the increase in the separated over-fired air ratio can effectively equalize the heat duty distribution. And the increasing of the furnace wall temperature will affect the furnace radiation heat transfer performance, which increases the flue gas average temperature. The boiler configurations including the flue gas recirculation, double furnace strategy, thermal insulation strategy and boiler local expansion strategy have the positive effects on decreasing the furnace heat duty to ensure the boiler safety. Finally, the novel S-CO_2 boiler configurations are proposed and the comprehensive evaluations are conducted on the boiler combustion, heat transfer and burnout characteristics, which show that the novel S-CO_2 boiler performance is promising and can provide a basis for the design of S-CO_2 boiler.