350MW超临界锅炉混煤掺烧试验研究

发布时间：2018-03-14 03:09

本文选题：混煤　切入点：热重分析　出处：《吉林大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着我国国民经济的快速增长和人民生活水平的提高,我国对电力的需求急剧增加,“电荒”现象时有发生。而火力发电仍然是我国目前主要的发电方式,随着装机容量不断扩大,电厂对煤炭的需求量也越来越大,大型电站常年出现煤炭供应不足的情况。面对电力的巨大需求和煤炭供应紧张的矛盾局面,电厂很难长期稳定地燃用设计煤种,而是燃用两种甚至多种煤炭,由于这些燃煤煤质特性差异较大,给锅炉的安全、经济运行带来燃烧不稳定、结渣加剧、污染物排放升高等问题。因此,电厂通常通过设计合理的掺混方案,来保障锅炉的安全、稳定和经济的运行。本文以350MW超临界锅炉作为研究对象,该锅炉的设计煤种是褐煤,但是褐煤的热值低,挥发分高,燃烧不充分容易产生结焦,为了解决其结焦严重,热效率低等问题,现对褐煤掺烧低品质的烟煤进行电厂实地试验研究,充分利用烟煤灰分含量低,热值高等特点,故从电厂实际情况出发,选择了贺斯格乌拉褐煤、沙尔塔拉褐煤和山西葛铺烟煤参与本试验研究。首先,采用HS-TGA-101热重分析仪对十种不同配比的混煤进行热重试验,总结不同混配比例混煤的着火温度变化规律,主要分析了两种煤种混配和三种煤混配时,褐煤掺烧烟煤时着火特性的变化和燃烧参数的变化,得出随山西葛铺烟煤混烧比例的增加,其混煤的可燃性指数C随之增小,混入沙尔塔拉比例的增加可燃性指数C随之增加,煤质稳定性能有所提升,为设计具体的混煤掺烧方案提供理论基础。其次,利用SDTGA2000自动工业分析仪对各种混煤方案做工业分析实验,得到实时的工业分析数据,为下一步计算最佳配比做基础。然后以购煤价格和混煤含硫量作为多目标模糊决策模型的目标函数,工业分析数据作为约束条件,经计算得到了满足经济性和环保性的最佳混配比,为下一步电站锅炉现场试验研究提供理论依据。最后,在某热电厂350MW-HG-1110/25.4-HM2锅炉进行为期30天的现场试验研究,单独燃烧校核煤种贺斯格乌拉褐煤和掺烧不同比例烟煤时的九种燃烧方案能否保证电厂锅炉的安全运行,通过分析试验期间温度参数变化对锅炉安全性的影响(主要分析了水冷壁温度、过热器及再热器温度、主蒸汽温度等)和结焦情况对锅炉混煤燃烧过程进行了安全性分析。
[Abstract]:With the rapid growth of China's national economy and the improvement of people's living standards, the demand for electricity in our country has increased sharply, and the phenomenon of "electricity shortage" has occurred from time to time. However, thermal power generation is still the main power generation mode in China at present. With the continuous expansion of installed capacity, the demand for coal in power plants is also increasing. Large power plants have a shortage of coal supply all year round. Faced with the contradiction between the huge demand for electricity and the tight supply of coal, It is very difficult for power plants to burn design coals steadily for a long time, but to burn two or even more kinds of coals. Because of the great differences in the coal quality characteristics of these coal-fired coal, it brings instability to combustion and aggravation of slagging for the safety and economic operation of boilers. Therefore, a reasonable mixing scheme is usually designed to ensure the safe, stable and economical operation of the boiler. In this paper, 350 MW supercritical boiler is taken as the research object, and the designed coal type of the boiler is lignite. However, lignite has low calorific value, high volatilization and insufficient combustion. In order to solve the problems of serious coking and low thermal efficiency, a field test study of bituminous coal mixed with lignite is carried out in power plant. Taking full advantage of the characteristics of low ash content and high calorific value of bituminous coal, Hesiguula lignite, Chartara lignite and Kepu bituminous coal from Shanxi are selected to participate in the experimental study. HS-TGA-101 thermogravimetric analyzer was used to carry out thermogravimetric tests on ten kinds of mixed coals with different proportions. The variation of ignition temperature of mixed coals with different blending ratios was summarized, and the mixing of two kinds of coals and three kinds of coals were mainly analyzed. The change of ignition characteristics and combustion parameters of lignite mixed with bituminous coal shows that the flammability index C of mixed coal increases with the increase of the blending ratio of Keshu bituminous coal in Shanxi Province, and the flammability index C increases with the increase of the proportion of mixed bituminous coal with Chartara. The stability of coal quality has been improved, which provides a theoretical basis for the design of specific mixed coal blending scheme. Secondly, the industrial analysis experiment of various mixed coal schemes is done by using SDTGA2000 automatic Industrial Analyzer, and the real-time industrial analysis data are obtained. Then the price of coal and sulfur content of mixed coal are taken as the objective function of multi-objective fuzzy decision model, and the data of industrial analysis are taken as constraint conditions. The optimum mixture ratio to meet the economic and environmental protection is obtained by calculation, which provides a theoretical basis for the next field test study of power plant boilers. Finally, a 30-day field test study is carried out on a 350MW-HG-1110 / 25.4-HM2 boiler in a certain thermal power plant. Can the nine combustion schemes of single combustion check coal and mixed bituminous coal ensure the safe operation of power plant boilers? By analyzing the influence of temperature parameters on boiler safety during the test period (mainly analyzing the water wall temperature, superheater and reheater temperature, main steam temperature, etc.) and coking, the safety analysis of boiler mixed coal combustion process was carried out.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM621.2

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