长期使用劣质煤作发电燃料的电厂，因烟气中飞灰浓度较大导致脱硝系统效率下降，增加机组超低排放难度。以贵州茶园电厂的W型火焰锅炉省煤器出口至上升烟道入口烟道为研究对象，采用数值模拟方法对烟气流动情况及飞灰颗粒运动轨迹进行研究。结果表明，省煤器灰斗对烟气中飞灰颗粒的收集效果并不明显，只能收集到少量烟气中的飞灰，飞灰收集率仅9.99%；在对选择性催化反应脱硝装置（selective catalytic reduction, SCR）的上升烟道入口处飞灰沉积特性模拟时发现，弯道处壁面飞灰沉积量为1.12 kg/s，占进入烟道飞灰总量的11.33%；在此基础上，提出两种上升烟道下方布置脱硝灰斗的设计方案，发现两种方案均能有效提高飞灰收集效率；当斜面与水平壁面的夹角为45°时效果最佳，飞灰收集率可以提升了约8.38%，且压降仅上升了2.25 Pa。

Power plants utilizing substandard coal for electricity generation often face reduced denitrification efficiency due to high fly ash concentrations in the flue gas, which complicates achieving ultra-low emissions. The flue gas duct from the economizer outlet to the riser duct entrance in the W-shaped flame boiler at Guizhou Chayuan Power Plant was investigated. Numerical simulations were conducted to analyze flue gas flow and fly ash particle trajectories. The results show that the economizer ash hopper is minimally effective, with a collection rate of only 9.99%. Simulation results reveale fly ash deposition on the wall at the SCR riser flue bend at 1.12 kg/s, representing 11.33% of total fly ash. Based on these findings, two design schemes for positioning a denitrification ash hopper below the riser flue are proposed to enhance fly ash collection efficiency. Optimal results are obtained with a 45° angle between the inclined surface and horizontal wall, increasing fly ash collection by 8.38% with a 2.25 Pa pressure drop increase.