摘要
随着我国电力需求的快速增长,火力发电机组逐步向大容量、超超临界燃煤机组发展。然而,锅炉设备受热面蒸汽侧部分管内壁及汽轮机主汽门、调门和主、再热蒸汽管道在高温下被水蒸气氧化,产生的氧化皮脱落堆积,易引起管道堵塞、爆管等危害,从而对锅炉的安全运行造成影响。通过文献检索、试验测试对氧化皮的形成机制、脱落机理进行了深入系统的分析。结果发现,氧化皮生成速度随管壁温度上升而加快,随管材抗氧化性提高而减慢。氧化皮与金属体线性膨胀系数差越大越容易引起氧化皮脱落。基于上述机理,从机组选型及设计调试、运行维护、炉水处理、锅炉控制等4个方面提出了合理的氧化皮防治措施,并在2×660 MW超超临界机组进行了近1 a的实践运行,其高温受热面未发生严重超温和爆管事件,有效地提高了锅炉运行的可靠性和经济性。
With the rapid growth of China’s power demand,thermal power units are gradually developing to large-capacity,ultra-supercritical coal-fired units.However,the inner wall of some tubes on the steam side of the heated surface of boiler equipment and the main turbine valve,valve and main and reheated steam pipeline are oxidized by water vapor under high temperature,and the resulting oxide skin peels off and accumulates,which can easily cause pipe blockage,pipe burst and other hazards,thus affecting the safe operation of the boiler.In this paper,the formation mechanism and the shedding mechanism of the oxide skin was analyzed deeply through literature review and experimental tests.Results showed that the rate of oxide scale formation was accelerated with the increase of pipe wall temperature and slowed down with the improvement of pipe oxidation resistance.The larger the difference between the linear expansion coefficient of the oxide scale and the metal body,the easier it was to cause the shedding of the oxide scale.Based on the above mechanism,the reasonable prevention measures of oxide scale were proposed from four aspects including unit selection and design debugging,operation and maintenance,furnace water treatment,boiler control and was implemented in a 2×660 MW ultra-supercritical unit for nearly one year,in which no serious incidents of superheat and tube burst occurred at the high temperature heating surface,effectively improving the reliability and economy of boiler operation.
作者
包永志
孙雨溪
胡善为
BAO Yong-zhi;SUN Yu-xi;HU Shan-wei(Shenhuabeidian Victory Energy Limited,Xilinhot 026000,China;College of Safety and Environmental Engineering,Shandong University of Science and Technology,Qingdao 266590,China)
出处
《材料保护》
CAS
CSCD
2021年第4期149-154,共6页
Materials Protection
关键词
超超临界锅炉
氧化皮
生成机理
脱落机理
防治措施
ultra-supercritical boiler
oxide scale
formation mechanism
shedding mechanism
prevention measures
