摘要
针对某电厂660 MW前后墙对冲燃煤锅炉侧墙水冷壁出现的高温腐蚀问题,提出了前后墙开孔(方案1)、侧墙开槽(方案2)以及二者组合(方案3)等3种贴壁风布置方案,并对各方案的防腐蚀效果进行了数值模拟分析。结果表明:方案1需要较多贴壁风来保证喷口射流刚性,以使O2扩散到侧墙中部的高温腐蚀区;方案2使用较少贴壁风便可在沿炉深方向的喷口附近区域取得良好的补氧效果,但贴壁风沿炉高方向的扩散范围有限,导致相当部分的高温腐蚀区无法获得O2补充;方案3吸收了前2类方案优点,其最优方案C仅用4.35%风率即使侧墙水冷壁高温腐蚀区域O2浓度基本达到2%(破坏还原性气氛所需浓度)以上,从而有效地解决了高温腐蚀问题。
In order to deal with the high temperature corrosion of the water-cooled wall of a 660 MW front and rear wall opposed coal-fired boiler, three cases were presented, including Scheme 1 with the wind in the front and rear walls, Scheme 2 with the wind in the side walls and Scheme 3 with the wind both in the front/rear and side walls. Then, the flow and combustion characteristic of different cases were simulated. The results show that in the Scheme 1, lots of closing-to-wall air is needed to ensure the rigidity of the jet, so that O2 diffused into the high temperature corrosion zone located in the middle of the side walls. In the Scheme 2, O2 could cover the water-cooled wall nearby the nozzles only when the jet with low velocity is introduced into the furnace. However, it is difficult for O2 to cover the upper part of the water-cooled wall In the Scheme 3 which took advantage of Scheme 1 and 2, only closing-to-wall air with the air volume rate of 4.35% could ensure that O2 concentration of the most region of the water-cooled wall exceeded 2%, which solved the high temperature corrosion problem effectively.
出处
《中国电机工程学报》
EI
CSCD
北大核心
2015年第20期5265-5271,共7页
Proceedings of the CSEE
关键词
前后墙对冲燃煤锅炉
高温腐蚀
贴壁风布置方案
数值模拟
front and rear wall opposed coal-fired boiler
high temperature corrosion
closing-to-wall air layout
numerical simulation
