文档介绍：毕业论文
作者: 学号:
系: 动力工程
专业: 热能与动力工程
题目: 电站锅炉后屏过热器壁温计算
及爆管研究
指导者:
(姓名) (专业技术职务)
评阅者:
(姓名) (专业技术职务)
2007 年 6 月
摘要
近年来,我国的火力发电机组逐渐向大容量方向发展。由于锅炉蒸汽参数的不断提高,过热器和再热器系统受热面积越来越大,设计和布置日趋复杂,不可避免地导致并联各管内的流量与吸热量发生差异。过热器受热面中的工质是高温高压的蒸汽,而受热面又处于烟气温度较高的区域,工作条件比较恶劣。因而受设计、制造、运行等诸多方面因素的影响,过热器受热面经常发生超温现象,严重时发生爆管事故。目前,大型电站锅炉爆管事故(BFT)已成为当前威胁发电设备稳定运行的突出矛盾,而且随着旧机组服役时间的增加及新机组投产量和参数的提高,这类事故还有逐年上升的趋势,是影响安全发供电的主要因素。研究和防止过热器爆管已成为保证火电厂安全经济运行和提高经济效益的关键课题之一。
本文以研究了爆管问题为主,对电站燃煤锅炉过热器超温、爆管的问题进行了综合研究,通过对过热器系统的热偏差理论的研究,详细分析了造成过热器超温、爆管的原因,给出了预防过热器超温、爆管的方法,并结合一台具体的锅炉,计算了在不同煤种、不同负荷的情况下其后屏几个危险点的管壁温度,建立了壁温与负荷的关系,提出了锅炉安全工作的负荷及燃料限制,并提出了技术改造方案。现场的热力实验印证了技术改造方法的可行性。
关键词:过热器、超温、爆管、壁温计算、技术改造
ABSTRACT
In recent years, thermal generator unit capacity rased more and more in china. With steam parameter in boiler increased continuously,heating surface area of superheater and reheater became bigger and bigger, and the design and arrangement became more and plex, and these lead to the flow and heat absorption capacity difference in parallel tubes unavoidably. Because the mediator working in the superheater are high temperature and high pressure steam, and the heating surfaces are in the high temperature fume area, so the working condition is bad. Overtmperature, even tube explosion in the heating surface of superheater always happen because of many elements in design, manufacture and present, tube explosion of power station (BTF} e an important problem influencing the safe of the power station operation. And with the increase of the time on active service of old units and improvement of operation amount and parameter on new units, this kind of accident has trend of rising year by year, and is the main factor influencing the safe of the operation. So, study on preventing tube explosion e one of the key subjects on power plant safe economical operation and increasing economic efficiency.
The research developed on the overtemperature and tube explosion of superheater in power plant and an