煤电机组深度调峰对锅炉受热面管的影响  

Analysis of influence of deep peak shaving on heating surface tubes of coalfired power units

作　　者：常伟 徐贤 魏然 王斌 于佳宇 马彪 CHANG Wei;XU Xian;WEI Ran;WANG Bin;YU Jiayu;MA Biao(China Energy Science and Technology Research Institute Co.Ltd Yinchuan Branch,Yinchuan 750000,China)

机构地区：[1]国家能源集团科学技术研究院有限公司银川分公司,宁夏银川750000

出　　处：《电力科技与环保》2022年第6期458-466,共9页Electric Power Technology and Environmental Protection

基　　金：国家能源投资集团有限责任公司科技项目(GJNY2022Y01)。

摘　　要：燃煤火电机组参与电网深度调峰已成常态,机组低负荷运行会对锅炉受热面(如水冷壁、过热器、再热器、省煤器等)产生一定的影响。为确保煤电机组在深度调峰低负荷时安全稳定运行及提高机组的调峰运行适应性,以西部地区某省34台燃煤火电机组为研究对象,通过四起锅炉受热面管泄漏实例,即660 MW超临界燃煤机组水冷壁管热疲劳开裂、660 MW超临界燃煤机组高温过热器超温爆管、350 MW超临界机组高温过热器泄漏、300 MW亚临界机组低温再热器泄漏,分析了机组深度调峰对锅炉运行的影响,并从宏观形貌、金相组织、裂纹形成过程等方面探讨了实例机组受热管面泄漏的原因。结果表明:(1)34台燃煤火电机组在参与深度调峰过程中普遍存在受热面管超温、壁温波动大、氧化皮脱落情况,其中19台机组出现受热面管失效事故,占比55.9%。(2)660 MW超临界燃煤机组水冷壁管疲劳开裂原因是当机组调峰50%负荷运行时,水冷壁金属壁温变化大(5~11℃/min),远超过标准要求(1.5℃/min)。(3)660 MW超临界燃煤机组高温过热器爆管原因是锅炉低负荷运行时金属壁温偏高,长时间处在超温环境下引发泄漏,漏点金相组织老化等级4.5级。(4)350 MW超临界机组深度调峰下限34%,高温过热器频繁超温运行导致氧化皮生成速度快,氧化皮脱落堵管过热引发爆管。(5)300 MW亚临界机组深度调峰下限36%,烟道挡板频繁调节,导致低温再热器管磨损减薄泄漏。为保证保煤电证机组在深度调峰时安全稳定运行,提出开展低负荷下稳燃试验及增设吹灰装置、水冷壁增加壁温没点、燃烧优化、升级材质、在尾部烟道加装防磨护板等锅炉精细化管理措施。It has become normal for coal-fired thermal power units to participate in the depth peak adjustment of the power grid.The low-load operation of the unit will have a certain impact on the heating surface of the boiler(such as water-cooled wall,overheater,reheater,coal saver and etc.).In order to ensure the safe and stable operation of coal power units at depth peak adjustment and low load,and to improve the peak adjustment operation adaptability of the unit,taking 34 coal-fired thermal power units in a province in the western region as the research object.Four examples of boiler heating surface pipe leakage,namely,660 MW supercritical coal-fired unit water-cooled wall pipe thermal fatigue cracking,660 MW supercritical coal combustion unit high-temperature superheater superheating pipe,350 MW supercritical unit high-temperature superheater leakage,300 MW subcritical unit low-temperature reheater leakage,have been analyzed the influence of unit depth peak regulation on boiler operation,and discussed examples from the aspects of macromorphology,metallographic structure,crack formation process and etc.Reasons for the leakage of the heating pipe surface of the unit.The results show that:(1)34 coal-fired power units generally have overtemperature,large wall temperature fluctuation and oxidised skin shedding in the process of participating in the deep peak regulation.Among them,19 units have thermal surface tube failure accidents,accounting for 55.9%.(2)The cause of fatigue cracking of the water-cooled wall pipe of the660 MW supercritical coal-fired unit is that when the unit is adjusted to the peak 50%load,the metal wall temperature of the water-cooled wall varies greatly(5~11℃/min),which far exceeds the standard requirements(1.5℃/min).(3)The cause of the explosion of the high-temperature superheater of the 660 MW supercritical coal-fired unit is that the metal wall temperature is high when the boiler is low-loaded,which causes leakage in an overtemperature environment for a long time,and the leakage point metallogr

关 键 词：煤电机组 深度调峰 受热面管 失效 

分 类 号：TK6[动力工程及工程热物理—生物能] X705[环境科学与工程—环境工程]