660 MW超超临界四角切圆锅炉烟气再循环墙式布置方式优化数值模拟OA

[Objective]To address the issues of low reheated steam temperature and local overheating of platen superheaters(PSH)during low-load operation of a 660 MW ultra-supercritical tangentially fired once-reheat boiler,this study proposed a wall-mounted flue gas recirculation(FGR)arrangement in the burner region.The aim was to synergistically raise reheated steam temperature and suppress PSH overheating while maintaining combustion stability.[Methods]Numerical simulation was performed at 40%rated load to optimize the proposed layout.First,the baseline case and corner-mounted and wall-mounted concentrated FGR arrangements were compared.Subsequently,the feasibility of wall-mounted grouped injection was investigated.[Results]The results indicated that:corner-mounted FGR significantly increased the ignition distance of pulverized coal jets,which adversely affected low-load combustion stability.Both fire-side and rear-side concentrated FGR increased the heat absorption of the high-temperature reheater,but neither could simultaneously mitigate PSH local overheating.Fire-side grouped FGR substantially enhanced heat absorption of the reheater but still carried a risk of PSH overheating,whereas rear-side grouped FGR reduced the overheating risk but yielded only limited reheater improvement.A combined grouped arrangement,in which flue gas was injected through the two lower layers on the fire-side wall together with the upper layer on the rear-side wall,increased the heat absorption of the reheater by 18.9%,effectively mitigated local overheating of the PSH,and maintained stable combustion.[Conclusion]These findings provide design and optimization references for safe,flexible,and efficient boiler operation across wide load ranges in next-generation coal-fired power plants.