燃煤电站锅炉低氮燃烧与SCR脱硝协同优化技术研究

发布时间：2017-12-31 04:34

本文关键词：燃煤电站锅炉低氮燃烧与SCR脱硝协同优化技术研究　出处：《上海电力学院》2017年硕士论文　论文类型：学位论文

【摘要】：目前,随着国家电力行业的快速发展,2016年全年的发电量达到5.37亿千瓦时,其中火力发电量约为3.97亿千瓦时,占总发电量的73.93%,而我国火力发电的原材料主要是以燃煤为主,2016年全国的供热耗用原煤达到1.92亿万吨。煤炭燃烧排放的NO_x,SO_2和粉尘是造成环境污染的重要污染源,其中,NO_x是造成光化学烟雾,酸雨以及雾霾的主要因素,因此减少电厂NO_x等污染物的排放显得刻不容缓。随着越来越严格的国家环保法规的实施,对火电厂NO_x排放的指标也越来越严格,火电厂为降低NO_x的排放也都采取了相应的措施。目前电站80%以上都采用四角切圆燃煤锅炉,并且大多采用低氮燃烧联合SCR脱硝技术降低NO_x的排放。在满足NO_x排放标准的前提下,如何调节煤粉燃烧和喷氨量,优化锅炉效率和SCR投运成本之间的关系,对燃煤电站锅炉环保系统节能增效具有很强的现实指导意义。本文通过阅读分析目前国内外关于如何降低火电厂NO_x排放的技术和方法,尤其针对300MW机组电厂如何优化氧量、SOFA风量,SOFA风摆角,满足既能保证机组的锅炉效率,又能降低NO_x排放,节省喷氨成本的要求。经过分析研究设计出了如何优化锅炉低氮燃烧和喷氨成本的试验方案并进行了试验研究。研究的主要内容和结论如下:1.试验研究氧量、SOFA风量、SOFA风摆角对锅炉效率和SCR入口NO_x排放量的影响。依据试验数据建立锅炉燃烧方式与锅炉效率、NO_x排放之间的特性关系,得到锅炉低氮燃烧特性曲线,以便分析观察燃烧方式对锅炉效率和NO_x排放的影响。2.试验研究SCR入口NO_x浓度变化与脱硝还原剂(尿素)运行成本之间的定量关系,同时分析NO_x浓度的变化对喷氨量和脱硝效率的影响。建立SCR脱硝装置喷氨成本特性曲线,以便分析观察SCR入口NO_x浓度对喷氨量的影响。3.综合优化锅炉燃烧方式对锅炉效率和NO_x排放量的特性曲线,建上海电力学院硕士学位论文立锅炉低氮燃烧与SCR联合脱硝运行的综合成本模型,并进行工况寻优,进行优化前后的经济性分析。结果表明,通过优化调整锅炉效率大约提高0.1%,SCR入口NO_x浓度大约减少20mg/m3,喷氨量减少16.44%,使燃煤锅炉在最佳的经济下运行。4.建立优化后氧量和SOFA风量的控制曲线,曲线兼顾锅炉效率和SCR脱硝成本的最优化,为电厂氧量和SOFA风量的调整提供理论指导。5.采用数值模拟的方法,对锅炉炉膛燃烧中不同运行方式进行了数值计算,数值模拟的结果与实测数值吻合,为后期运行优化提供了指导。
[Abstract]:At present, with the rapid development of the national power industry, in 2016, the power generation reached 537 million kilowatt-hours, of which the thermal power generation capacity is about 397 million kilowatt-hours, accounting for 73.93% of the total electricity generation. In 2016, the national heating consumption of raw coal reached one hundred and ninety-two million nineteen thousand and two hundred tons. Coal combustion emissions of NO_x. SO_2 and dust are important sources of environmental pollution, among which Nox is the main cause of photochemical smog, acid rain and haze. Therefore, it is urgent to reduce the emission of NO_x and other pollutants in power plants. With the implementation of more and more strict national environmental laws and regulations, the targets of NO_x emissions from thermal power plants are becoming more and more stringent. Corresponding measures have been taken to reduce NO_x emission in thermal power plants. At present, more than 80% power stations use tangential tangential coal-fired boilers. And most of the use of low nitrogen combustion combined with SCR denitrification technology to reduce NO_x emissions. In the premise of meeting the NO_x emission standards, how to adjust the amount of pulverized coal combustion and ammonia injection. Optimize the relationship between boiler efficiency and SCR operation cost. This paper analyzes the technology and methods of how to reduce NO_x emission of coal-fired power plant by reading and analyzing. Especially for 300MW unit power plant, how to optimize the oxygen quantity and sofa wind swing angle can not only guarantee the boiler efficiency, but also reduce the NO_x emission. The requirements of saving the cost of ammonia injection. The experimental scheme of optimizing low nitrogen combustion and ammonia injection cost of boiler is designed and studied. The main contents and conclusions of the study are as follows:. 1. Experimental study of oxygen content. The influence of SOFA air volume and sofa wind swing angle on boiler efficiency and SCR inlet NO_x emission. Based on the experimental data, the characteristic relationship between boiler combustion mode and boiler efficiency is established. The characteristic curve of boiler low nitrogen combustion was obtained. In order to analyze and observe the effect of combustion mode on boiler efficiency and NO_x emission. 2. The quantitative relationship between SCR inlet NO_x concentration change and operation cost of denitrification reductant (urea) was studied. At the same time, the effect of NO_x concentration on ammonia injection and denitrification efficiency was analyzed. The characteristic curve of ammonia injection cost of SCR denitrification plant was established. In order to analyze and observe the effect of SCR inlet NO_x concentration on ammonia injection. 3. Comprehensive optimization of boiler combustion mode on boiler efficiency and NO_x emissions characteristic curve. The comprehensive cost model of low nitrogen combustion and SCR combined denitrification operation of boiler was established in the master's degree of Shanghai Electric Power College, and the optimization was carried out, and the economic analysis before and after optimization was carried out. By optimizing the boiler efficiency, the concentration of NO_x is reduced by 20mg / m3, and the ammonia injection is reduced by 16.44%. The control curve of the optimized oxygen quantity and SOFA air volume is established, which takes into account the optimization of boiler efficiency and SCR denitrification cost. It provides theoretical guidance for the adjustment of oxygen quantity and SOFA air volume in power plant. Numerical simulation method is used to calculate the different operation modes of boiler furnace combustion. The results of numerical simulation are in agreement with the measured values, which provides guidance for later operation optimization.
【学位授予单位】：上海电力学院
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X773

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