【作者】 张伟；

【导师】 黄仙； 蔡宝玲；

【作者基本信息】 华北电力大学(北京) ， 控制工程， 2016， 硕士

【摘要】 国电泰州电厂3号机组于11月进行的性能试验表明,超超临界二次再热机组比同容量一次再热机组具有更好的经济效益和环保效益。在70(0℃等级的超超临界机组所需新型合金材料取得突破、机组大规模投运之前,二次再热超超临界是可行的能提高机组热效率的有效手段。与常规一次再热机组相比,采用二次再热技术的机组锅炉和汽轮机结构更加复杂,低压再热汽温作为新的被控对象,相关的控制策略研究尚不充分。本文依托西安热工研究院有限公司华能莱芜电厂1000MW二次再热机组工程项目,对二次再热机组低压再热汽温的动态特性展开研究,主要包括以下几个方面:(1)查阅二次再热技术相关的国内外文献,总结了二次再热技术的特点和发展现状,在700℃等级新型耐高温合金材料取得突破之前,二次再热技术是提高机组热效率的有效手段;(2)研究单元机组系统建模的方法,将仿真支撑平台Apros选作建模仿真工具,参考1000MW超超临界二次再热机组的设计资料,搭建1000MW超超临界二次再热机组原理性模型;(3)确定低压再热汽温动态特性的研究方案,将搭建好的模型通过OPC通讯工具与Matlab建立连接,通过Matlab记录相关的试验数据;在100%BMCR负荷工况下,选取风量、给水流量、燃料量、烟气再循环风机挡板开度、烟气分配挡板开度等作为扰动量,进行单变量扰动试验,将部分试验结果与常规一次再热机组对比,分析低压再热汽温的动态特性;机组低压再热汽温受烟气分配挡板和烟气再循环率变化的显著影响,但其作用时间较长,低压再热蒸汽减温喷水可以在短时间内有效地影响低再汽温但会影响到机组的经济性。所以可以将烟气分配挡板和烟气再循环风机出口挡板作为低再汽温的主要调节手段,将低再减温喷水作为辅助调节手段。通过本文对超超临界二次再热机组二次再热汽温的动态特性的分析,对于相关的控制策略研究有一定的帮助。更多还原

【Abstract】 The performance test of the No.3 unit in Taizhou power plant in November 2015 shows that ultra supercritical double-reheat units have better capacity than single reheat units on economic benefits and environmental benefits.Before the required new alloy materials of 700℃ degree ultra supercritical units make a breakthrough and get to large-scale production,ultra supercritical(USC)double-reheat technology can be an effective feasible to improve the thermal efficiency of the unit.Comparing with a conventional reheat unit,the boiler and the steam turbine structure of a double-reheat technology is more complex.Low-pressure steam temperature is a new controlled object and its control strategy is still in the exploratory stage.Relying on Laiwu 1000MW USC double-reheat unit of Huaneng Group,analysis on dynamic characteristics of low-pressure reheat steam temperature has been done in this paper:(1)By searching the relevant literature on the development of double-reheat technology,the characteristics and development status of the double-reheat technology are summarized.Before the required new alloy materials of 700℃ degree ultra supercritical units make a breakthrough,double-reheat ultra supercritical technology can be an effective feasible to improve the thermal efficiency of the unit.(2)Method for modeling the system of unit system is analyzed.The simulation support platform APROS is chosen as the modeling tool.The material of 1000MW ultra supercritical double-reheat unit is taken as reference to grasp its structure and to build its principle model.(3)Research project on dynamic characteristics of low-pressure steam temperature is made.The model having been built is communicated by OPC to Matlab to record related test data.Under 100%BMCR condition,wind flow、feedwater flow、coal flow、position of flue gas recirculation fan baffle and position of flue gas distribution baffle are chosen as disturbance factor.By Single variable disturbance test,comparing with conventional single-reheat unit,analysis and research on dynamic characteristics of low-pressure reheat steam temperature in 1000MW ultra supercritical double-reheat units are made.Low-pressure steam temperature is significantly affected by gas distribution baffle and flue gas recirculation rate,but its effect takes long time.Low-pressure reheat steam coolwater can effectively influence low reheat steam temperature in a short period of time,but will affect the units of the economy.So the gas distribution baffle and flue gas recirculation fan outlet baffle can be set as the main control means of steam temperature and the low spray water be set as auxiliary means of regulation.By analysis on dynamic characteristics of low-pressure reheat steam temperature in 1000MW ultra supercritical double-reheat unit,the research on the related control strategy is hope to be helpful.更多还原