摘要
燃烧过程中控制NO_(x)生成是最直接经济有效的低NO_(x)燃烧技术。煤粉预热-燃烧技术以其巨大的低NO_(x)燃烧潜力逐渐得到重视。煤粉预热-燃烧技术降低NO_(x)生成的主要思路在于:煤粉进入炉膛燃烧前,通过设置独立的高温低氧强还原性物理空间对煤粉进行预热,挥发分在预热区内快速析出并进行相应转化,促进挥发分N的释放并增加挥发分N还原为N_(2)的比例,从而降低煤中N被氧化成NO_(x)的概率;在此基础上,通过结合空气分级和MILD燃烧等低NO_(x)技术对预热产物进行相应的燃烧组织,进一步降低预热产物燃烧过程中NO_(x)的生成。现阶段煤粉预热-燃烧技术根据预热热源与装置的不同可以分为燃气辅热式煤粉预热-燃烧技术、流化床煤粉预热-燃烧技术、燃烧器煤粉预热-燃烧技术。其中燃烧器煤粉预热-燃烧技术通过优化设计,将煤粉自预热技术与径向及轴向多级逐级配风技术、燃料浓淡分离与分级送粉等技术有机结合,在保证高效低NO_(x)同时,具备低成本与改造灵活性的优势。实际应用结果表明:燃烧器煤粉预热在运行稳定性、变负荷适应性及低NO_(x)燃烧方面均表现出优异性能。
Reducing NO_(x) formation during pulverized coal(PC)combustion process is the simplest and most efficient way to minimize NO_(x) pollution.PC preheating and combustion technology has been paid more and more attention because of its great potential in low NO_(x) com⁃bustion.The key idea of preheating-low NO_(x) combustion is that before pulverized coal enters the furnace for combustion,the pulver⁃ized coal is preheated by setting an independent physical space with high temperature,low oxygen and strong reducibility,and the volatile is rapidly precipitated and transformed in the preheating area,so as to promote the release of volatile N and increase the proportion of vola⁃tile N reduced to N_(2),so as to reduce the probability of N in coal being oxidized to NO_(x).Meanwhile,by integrating low-NO_(x) technology,such as air staging and MILD combustion,the formation of NO_(x) is further reduced.So far,according to different preheating heat sources and preheating devices,PC preheating technology can be divided into gas-fired preheating,fluidized bed preheating and self-preheating burn⁃ers.Among them,self-preheating burner organically combines the pulverized coal self-preheating technology with the radial and axial mul⁃tistage step-by-step air distribution technology,fuel concentration and dilution separation and graded powder feeding technology through optimal design,which has the advantages of low cost and transformation flexibility while ensuring high efficiency and low NO_(x).The self-preheating burner shows excellent operation stability,load adaptability and low NO_(x) production by integrating self-preheating,multi air staging,fuel-rich/lean separation and fuel staging technology.
作者
王帅
刘洋
刘愿武
牛艳青
朱广庆
薛旭峰
惠世恩
WANG Shuai;LIU Yang;LIU Yuanwu;NIU Yanqing;ZHU Guangqing;XUE Xufeng;HUI Shien(State Key Laboratory of Multiphase Flow in Power Engineering,School of Energy and Power Engineering,Xi′an Jiaotong University,Xi′an 710049,China;Xi′an Thermal Power Research Institute Co.,Ltd.,Xi′an 710032,China;Xi′an Jiaoda Siyuan Technology Co.,Ltd.,Xi′an 710043,China)
出处
《洁净煤技术》
CAS
北大核心
2022年第4期33-41,共9页
Clean Coal Technology
基金
中央高校基础科研业务费资助项目(xtr042019007)。
关键词
预热-燃烧
辅热式
流化床预热
自预热燃烧器
低NO_(x)燃烧
preheating-combustion
gas fired preheating
circulating fluidized bed preheating
self-preheating burner
low NO_(x)combustion
