Investigations of Combustion Stability in a 660 MW Supercritical W-Flame Boiler Under Low Load

The proposal of carbon neutrality and peak carbon emissions indicated that the thermal power generating units will operate at lower load in the near future. The combustion stability is the key problem especially for the W-flame boiler with low volatile coal burnt, such as anthracite or lean coal. Therefore the combustion stability under low loads was studied in a 660 MW supercritical W-flame boiler through a series of experiments and CFD modeling work at 100%, 60%, 55%, 45% and 35%THA conditions. The results show that the load has little effect on the ignition distance of pulverized coal particles due to the comprehensive effects of the lower temperature in the furnace, the finer pulverized coal and the decreased concentration of the pulverized coal. The operation of burners on both sides and the reduction of exhaust air injection amount are beneficial to improve the combustion stability under low load condition. It is clear that the high temperature flame in the furnace cannot be kept under the condition of 35%THA. And the flame in the boiler will be extinguished in the predicted results of numerical simulation. © 2022, Science Press. All right reserved.