摘要
【目的】针对某650 MW超临界旋流对冲锅炉水冷壁的高温腐蚀问题,研究不同贴壁风率对炉膛燃烧特性的影响,以优化防腐效果并控制NO_(x)排放。【方法】本文以某650 MW超临界旋流对冲锅炉炉膛为研究对象,通过数值模拟方法,分析0%、1.4%、2.6%、3.8%不同贴壁风率对炉膛内的温度、O_(2)浓度、CO浓度及出口烟气参数的影响,CO浓度≥3%的区域占比为高温腐蚀面积比,作为本文评价指标。【结果】模拟结果表明,原始工况下侧墙冷灰斗至燃尽风区域的CO浓度高达8.5%,与实际腐蚀区域吻合。通过在侧墙加装不同风率的贴壁风系统,发现适量的贴壁风能够显著降低近壁面CO浓度,减少高温腐蚀区域,2.6%贴壁风率下腐蚀安全区域(CO<3%)占比超95%,有效缓解高温腐蚀。同时,加装贴壁风系统有利于主燃区煤粉的充分燃烧,降低炉膛出口的未燃尽碳比例,从2.4%降至1.4%,但NO_(x)排放增加约6.0 mg/m^(3),出口烟温下降,氧量上升。【结论】综合考虑防腐效果、改造成本及排放限制,2.6%的贴壁风率为最优方案,可在保证燃烧稳定性的同时显著减少高温腐蚀,并平衡NO_(x)控制需求。
[Objective]To address the high-temperature corrosion issue in the water-cooled walls of a 650 MW supercritical opposed wall-fired boiler,this study investigates the effects of different near-wall air rates on combustion characteristics,aiming to optimize corrosion resistance while controlling nitrogen oxide(NO_(x))emissions.[Methods]Numerical simulations were conducted to analyze the impacts of near-wall air rates(0%,1.4%,2.6%,3.8%)on furnace temperature,O2 concentration,CO concentration,and flue gas parameters.The corrosion-safe area ratio(regions with CO concentration<3%)was adopted as the evaluation criterion.[Results]The results showed that under the original condition,CO concentration near the sidewalls reached 8.5%,consistent with actual corrosion zones.Implementing near-wall air significantly reduced CO concentration;at a 2.6%air rate,over 95%of the sidewall area became corrosionsafe.Additionally,near-wall air enhanced coal combustion efficiency in the main combustion zone,reducing unburned carbon content(from 2.4%to 1.3%).However,NO_(x)emissions increased by approximately 10 mg/m^(3),with lower flue gas temperature and higher oxygen levels at the furnace exit.[Conclusion]Considering anti-corrosion effectiveness,economic costs,and emission standards,a 2.6%near-wall air rate is identified as the optimal solution.It effectively mitigates high-temperature corrosion,maintains combustion stability,and balances NO_(x)control requirements.
作者
杭文林
潘虎
岳峻峰
黄亚继
HANG Wenlin;PAN Hu;YUE Junfeng;HUANG Yaji(Jiangsu Guoxin Yangzhou Power Generation Co,Ltd,Yangzhou 225131,Jiangsu China;Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education,Southeast University,Nanjing 210096,Jiangsu China;Jiangsu Frontier Electric Technology Co,Ltd,Nanjing 211102,Jiangsu China)
出处
《电力科技与环保》
2025年第3期488-496,共9页
Electric Power Technology and Environmental Protection
基金
江苏省碳达峰碳中和创新专项(BE2022604)。
关键词
旋流对冲锅炉
高温腐蚀
CO
贴壁风
数值计算
opposed wall-fired boiler
high-temperature corrosion
CO
near-wall air
numerical calculation
