【作者】 李东；

【导师】 秦裕琨； 孙绍增；

【作者基本信息】 哈尔滨工业大学 ， 热能工程， 2010， 硕士

【摘要】 煤粉燃烧的过程中会产生大量烟尘、SO₂、NOx和CO₂等大气污染物,同时还会释放出有害有毒的微量金属元素,如:Hg、Pb、As、Se等,对环境及人体健康危害很大。因此,解决燃煤污染问题已经迫在眉睫。通过燃烧法控制反应条件以及投入添加剂脱除大部分的NOx,并在一定程度上脱除SOx和汞,再进一步配合其他中、低温燃烧污染物控制技术,可以大大降低锅炉进行污染物脱除和控制的成本,获得良好的经济效益。本文首先介绍了国内外燃烧法控制污染物减排的研究现状,阐述了炉内联合脱除NOx、SO₂和汞的意义;借鉴德国斯图加特大学携带流燃烧反应器参数,设计搭建了多反应控制段携带流反应器多功能试验系统。它主要包括反应器炉体、给粉系统、温度控制系统、气体供给系统、取样分析系统、冷却系统和排烟系统。为了了解试验台整体性能,对实验系统进行了调试试验,包括:系统气密性、油冷却系统、给料系统等调试试验,并进行了炉内温度场标定试验、结渣试验以及煤粉燃烧特性试验。针对炉内大给粉量燃烧不稳定引起的爆燃、炉内风粉混合不均匀、煤粉燃尽效果较差等问题,提出了在炉内加入侧二次风的改进措施。利用FLUENT数值模拟软件,对改进后的结构进行了数值模拟,通过对炉内流场速度分布、颗粒轨迹、颗粒浓度,以及炉内各水平截面及中心截面O₂、CO、CO₂摩尔浓度的分析,优化了相关参数,得出侧二次风位置h=37mm,风量配比:Q1=30%、Qh=20%、Qc=50%是本次试验的优化方案中的最好的改造方案。改进后的调试试验结果表明,加入侧二次风措施可有效改善炉内风粉混合问题,优化炉内燃烧。更多还原

【Abstract】 During the process of coal combustion, large amount of pollutant is produced, such as SO₂、NOx、CO₂ etc, and harmful toxic trace metal elements are released, such as Hg、Pb、As、Se etc,which do great harm to the eco-enviroment and human health. Consequently, the coal-fired pollution problems become more and more urgent. At present,most NOx can be removed from flue gas by controlling the combustion reaction conditions and putting additives into the furnace while some SOx and mercury also can be removed at the same time. Furtherly,It is more significant that this technology is used with other moderate and low-temperature combustion pollution control technologies, so this can greatly reduce the costs of removal of pollutants in the boiler and get good economic benefits.Controlled by combustion reaction conditions and additives put into removal of most of the NOx, and to some extent on the removal of SO₂ and mercury. Further with the other the moderate and low-temperature combustion pollution control technologies, we can greatly reduce the costs of removal of pollutants in the boiler and get good economic benefits.First of all, in this paper the background and present state of subject research about combustion tenologies of control pollutants in domestic. home and abroad are discussed, introducing the significance of combuined removal the NOx、SO₂、Hg at high temperature in the boiler. Refering to the Entrained Flow Reactor in University of Stuttgart, the Entrained Flow Combuster with Multiple Reaction Segment versatile experiment system was designed and built. The experiment system could do research on combined removal of NOx、SO₂、Hg in furnace simulataneously, including reactor furnace, the feeding system, temperature control system, gas supply system, the sample analysis system, cooling system and exhaust emission system etc.In order to get the total functions of the experiment system, much experiment of debug system was done, including the tests of air-tightness、oil cooling system and feeding system, what’s more, calibration experiment of the furnace temperature、slagging experiment and combustion characteristics of coal. During the experiment, some problems such as deflagration when feeding large amount of coal、heterogeneous mixtures of the furnace wind were discovered. In order to optimize the system, adding the two sides secondary air measure in the furnace and doing numerical simulation of the reformed structure. By analyzing the results of cold numerical simulation results and the horizontal sections and the center sections mole fraction of O₂, CO, CO₂, we got the most optimal program.The result of doing experiment at the reformed structure prove the optional method can effectively improve the heterogeneous mixtures of the furnace wind problem and combustion conditions.更多还原