【作者】 张春生；

【导师】 孙万云； 田沛； 彭根来；

【作者基本信息】 华北电力大学 ， 控制工程， 2011， 硕士

【摘要】 近年来随着国民经济的快速增长,电力需求的不断提高,机组容量增加和蒸汽参数的提高,电厂运行的可控性及安全性对国民经济发展起着直接的制约作用。电厂中化学水处理是火电厂重要的生产过程,国内多数电厂的化学水处理系统普遍存在自动化程度偏低、生产状况落后的现象,从而造成整个化学汽水处理流程中众多影响因素彼此间不能及时协调、及时响应处理,往往会误开阀门对生产产生不利影响。因此,在火力发电厂中,为了提高生产效益,实现综合化控制系统,水处理工作对保证发电厂的安全、经济运行具有十分重要的意义。本文主要针对张家口发电厂一期制水DCS系统改造,全面介绍了张家口发电厂化学制水状况,以及改造前制水控制系统存在的问题,并详细的阐述了一期制水进行DCS改造的必要性和紧迫性。同时,介绍了DCS控制系统在国内发展现状,简要说明了分散控制系统的特点,组件系统和分散控制系统结构图。张家口发电厂化学水处理过程DCS系统改造采用的是四方公司设计生产的分散控制系统,文中说明了四方公司DCS系统的主要性能指标,参数指标。通过改造实现了张家口发电厂一期制水电厂化学水处理DCS系统的优化、升级。为评价化学制水DCS系统改造后效果,对化学处理水系统进行了改造后的测试实验研究,实验结果表明采用四方公司自主研发的CyberControl软件和CSC800控制硬件的全厂制水系统,改造完成后系统具备自动制水、自动再生、制水计量、水质监测、流量控制、液位调节、压力保护、上位机监控和辅控网集中控制等功能,实现了全厂制水工艺的全方位自动控制。化学制水DCS系统改造后提高了水处理工艺过程的自动控制程度和管理水平,促进发电企业长远快速发展具有重要的意义,同时也为同类型机组DCS系统改造提供宝贵经验。更多还原

【Abstract】 In recent years,the demand of electricity is gradually enhances unceasingly as the rapid growth of the national economy, the suppy of power coal begins to be dificit and then cause the price of power coal to increase. And each power generation company has started to blend the designed coal with other coals in order to reduce consum and increase the competitiveness . Therefore, the study for mixing bituminous boiler with lignite is important for practical significance.This paper assesses the 350MW unit boiler of Fuxin Power Generation as the research object, and researches the ignition characteristics of bituminous boiler lignite, the characteristics of burning , the technology of stable combusion, the measures of blending coals and so on. Because of the lignite containing more volatile and moisture than the designed coal t, coal handing system, pulverizing system and pulverized coal feeding system is easy to explode, mixing coals will lead to lacking dry in coal mill and drastically redusing the efficiency of boiler. Therefore, due to amplifing the maximum limit of the mixing lignite proportion and reducing cost, and meeting to be combustion design coal at the same time, the scheme is put forward in this paper to take somke from the export of the dust collector into the export of primary air fan and send the blending smoke into the coal mill,it will improve the dry of the coal mill,reduce the oxygen consumption in the export of the coal mill,and improve to prevent explosion from the pulverizing system.We did the experiment for the reformed boiler with mixing bituminous with lignite to assess the result of the reformed boiler,the results showed that the pulverizing system could meet dry and safety explosion-proof requirements when the boiler mixed 50% lignite, and the maximum contributing of the mills was 72t/h to meet units with the maximum requirements of the boiler.The concentration of the oxynitride emission decreased by 39.1 mg/m3 after runing the cold smoke system,and the efficiency of the boiler reached to 92.25%. Not only it is an important significance to amplify the fuel limit, reduce the tension of the power coal and rapidly promote the long-term development of the power generation enterprises, but also it is valuable experiment for the same type of units.更多还原