低NOx燃气燃烧技术研究进展Research progress of low NOx gas combustion technology
崔名双,李小炯,苗鹏,郑祥玉,邢文朝,宋强
CUI Mingshuang,LI Xiaojiong,MIAO Peng,ZHENG Xiangyu,XING Wenzhao,SONG Qiang
摘要(Abstract):
气体燃料具有易于点火、燃烧迅速、燃烧完全等特点,且氮、硫、灰分低,因此燃烧后产生的污染物相对较少,属于较清洁的燃料,且国家燃气补贴政策的实施,使气体燃料燃烧近年来有很好的发展前景。但随着国家对大气污染物的控制更加严格,控制气体燃料燃烧过程中NO_x的生成至关重要。笔者介绍了不同种类NO_x的产生机理及影响因素,并基于NO_x的产生机理提出控制措施,分析目前应用较广泛的燃气燃烧技术的低氮原理及应用现状,最后提出燃气燃烧器应用的展望。燃气燃烧过程中主要以热力型NO_x及快速型NO_x为主,温度和过量空气系数是影响NO_x生成的主要影响因素。燃烧温度高于1 500℃时,热力型NO_x呈指数型增长,温度是影响NO_x生成的最重要因素。根据NO_x产生机理,低NO_x燃烧技术的实质是降低最高燃烧温度,控制燃烧区燃料浓度以及氧浓度,缩短烟气在高温区的停留时间,破坏NO_x生成的最佳条件,最终抑制NO_x的生成。低NO_x燃烧技术一定程度降低了NO_x的生成,但又会破坏整个燃烧进程,对燃烧和放热过程造成不利影响,降低了燃烧效率和传热效率,因此如何解决这些矛盾是亟需解决的问题。在实际应用中,应根据需求选择合适的燃烧技术,同时可将不同燃烧技术相结合起到稳燃、低氮的效果。应用较广泛的燃气燃烧技术主要是阶段型燃烧技术、烟气再循环燃烧技术、无焰燃烧技术等,其中催化燃烧技术发展前景较好,目前已应用于多个领域,其催化剂的热稳定性和寿命问题是限制其工业上广泛应用的核心问题。
Gas fuel has the characteristics of easy ignition,rapid combustion and complete combustion,and its nitrogen,sulfur and ash content are low,and the content of pollutant is relatively low after combustion,which belongs to cleaner fuel.In addition,with the implementation of national gas subsidy policy,gas fuel combustion has a good development prospect in recent years.However,with the country's stricter control of air pollutants,it is very important to control the formation of nitrogen oxides in the process of gas fuel combustion.Firstly,in the paper,the production mechanism and influencing factors of different kinds of Noxwere introduced,and the control measures were put forward according to the production mechanism of different kinds of NO_x.Secondly,based on the NO_xgeneration mechanism,the low nitrogen principle and application status of gas combustion technology widely used at present were analyzed.Finally,the conclusion of this paper and the prospect of gas burner application were puts forward.It is considered that the main factors in the process of gas combustion are thermal NO_xand fast NO_x,and temperature and excess air coefficient are the main factors affecting NO_xgeneration.When the combustion temperature is higher than 1 500 ℃,the thermal NO_xincreases exponentially,and temperature is the most important factor affecting the generation of NO_x.According to the mechanism of Noxgeneration,the essence of low NO_xcombustion technology is to reduce the maximum combustion temperature,control the fuel concentration and oxygen concentration in the combustion area,which shorten the residence time of flue gas in the high temperature area,and destroy the best conditions of NO_xgeneration,and finally inhibit the generation of NO_x.These combustion technologies reduce the generation of NO_xto a certain extent,but it will destroy the whole combustion process,which causes adverse effects on the combustion and heat release process,and reduces the combustion efficiency and heat transfer efficiency,so how to solve these contradictions is an urgent problem.In practical application,it is necessary to select the appropriate combustion technology according to the demand,and at the same time,it can combine different combustion technologies to achieve the effect of stable combustion and low nitrogen.At present,the most widely used gas combustion technologies are staged combustion technology,flue gas recirculation combustion technology,flameless combustion technology and so on.Catalytic combustion technology is a promising combustion technology,which has been applied in many fields.The thermal stability and life of catalyst are the core problems limiting its wide application in industry.
关键词(KeyWords):
燃气燃烧;低氮;燃烧技术;生成机理
gas combustion;low nitrogen;combustion technology;formation mechanism
基金项目(Foundation): 煤炭科学技术研究院科技发展基金项目技术创新项目(2018CX02)
作者(Author):
崔名双,李小炯,苗鹏,郑祥玉,邢文朝,宋强
CUI Mingshuang,LI Xiaojiong,MIAO Peng,ZHENG Xiangyu,XING Wenzhao,SONG Qiang
DOI: 10.13226/j.issn.1006-6772.20011801
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