抑制氮氧化物无烟燃煤技术及其应用
文献类型：学位论文
| 作者 | 徐有宁 |
| 学位类别 | 博士 |
| 答辩日期 | 2000-11 |
| 授予单位 | 中国科学院研究生院 |
| 导师 | 李静海 |
| 关键词 | 氮氧化物 烟黑 煤燃烧 |
| 其他题名 | Nox-Suppressed and smokeless coal combustion technology and its application |
| 学位专业 | 燃料煤 |
| 中文摘要 | 本文对抑制氮氧化物无烟燃煤技术进行了理论和实验研究。抑制氮氧化物无烟燃煤炉的工作过程是使煤先在还原气氛中气化，产生半焦和煤气，它们再分别进行富氧的主燃烧室燃烬。本文的目的是要揭示该技术降低氮氧化物和烟黑排放的机理，找到优化的结构参数，设计开发新炉型。主要研究内容包括：针对一台抑制氮氧化物无烟燃煤实验中，研究通风方式、气化室气体成分、反应温度和煤气停留时间等因素影响NO_x和烟黑排放的规律；采用Navier-Stokes方程模拟气化室的流场；应用CHEMIKIN软件包对气化室生成NO_x的化学动力学进行模拟计算。研究结果表明，该技术降低氮氧化物和烟黑的主要机理为：气化室生成的干馏煤气具有先上升后下降的流动特性，此特性使煤气在干馏区停留时间增长，推迟了干馏煤气与火焰中的O、OH粒子接触，有利于干馏煤气中的NH_3气体被分解为N_2和H_2，煤气中燃料氮生成的NO_x在进入氧化气氛的焦炭层之前被其中的CO和H_2等气体还原民N_2,从而减少了NO_x的排放。气化室生成的煤气穿过氧化气氛的半焦层时，限制了煤气生成烟黑所需要的空间，并使已形成的烟黑粒子吸附在半焦表面，然后被燃烬，煤气在半焦层中与空气充分混合，以近似预混火焰的形式在主燃烧室燃烧，减少了烟黑的排放。作者申请了“中间加煤两侧燃烧抑制氮氧化物无烟燃煤炉”专利，解决了该技术不能燃用易结焦煤的问题，根据该专利设计出负荷为(300～1400) KW的锅炉系列；开发了取暖做饭两用小型炉系列；改造了一台464KW的工业窑炉，为该技术拓宽了应用领域；设计了一台700KW链条炉，为该技术向机械化燃煤方式发展奠定了基础。已投入使用的炉型排烟林格曼数均小于1，NO_x浓度小于240mg/Nm~3，燃烧效率与相同负荷的固定床燃煤炉相比明显提高。 |
| 英文摘要 | The present thesis is devoted to theoretical and experimental investigation of a new NO_x~- and soot-suppressed grid furnace technology applicable for small and medium scale coal combustion units. The combustion process is separated into two spatial and temporary decoupled steps, which are the pyrolysis of the coal in an oxygen-free environment and the subsequent combustion of char and pyrolysis gas in the oxygen-rich zone of the furnace. Purpose of this research was to reveal the main mechanisms and interdependencies of NO_x and soot formation and destruction and to optimize design parameters for specific types of small scale stoves. Experiments were carried out with a multi-function domestic stove (heating, cooking, hot water preparation) to understand how design and operating parameters of the pyrolysis and combustion zones influence the gas compositions in different locations and the final emission characteristics. The coal conversion process was further analyzed using a mathematical model which involves a hydrodynamic submodel based on the N-S-equations to describe the gas flow structure in the different zones of the stove, and a submodel utilizing the CHEMKIN II-package to represent the main gas-phase reactions involved, respectiv ely. Theoretical as well as experimental results propose the following main mechanisms effective for NO_x~- and soot-suppression: Coal gas generated under reducing conditions in the "pyrogenic" section of the gasification chamber mainly contains NH_3 as nitric component. Countercurrent flow of the coal gas increases its residence time in the pyrogenic section and defers contact with O and OH radicals present in the flame, leading to predominant decomposition of NH_3 into N_2 and H_2. Already formed NO_x is significantly reduced by CO and H_2 and possibly to a small extent by NH_3 due to a sufficient time delay before the coal gas reaches the high temperature and oxygen rich combustion zone. Here, soot agglomeration is limited by the low voidage of the char layer and the therefore small residence time. Already developed soot particles are adsorbed by the char an burned out. In addition, the char layer supports rapid mixing between coal gas and air, favoring premixed combustion. Several different furnaces were developed in this work: 1. A "two-path" NO_x~- and soot-suppressed coal combustion boiler developed with a load ranging from 300KW to 1400KW avoiding the common problem of excessive slag formation; 2. A redesigned 464 KW kiln; 3. A travelling grate boiler with a design load of 700KW as the first kind of this type, designed according to the principles of NO_x~- and soot-suppression. For all of the above furnaces, measured NO_x emissions were below 240mg/Nm~3, Ringelmann Numbers were below 1 and the combustion efficiencies were raised outstandingly. |
| 语种 | 中文 |
| 公开日期 | 2013-09-26 |
| 页码 | 138 |
| 源URL | [http://ir.ipe.ac.cn/handle/122111/1924]  |
| 专题 | 过程工程研究所_研究所（批量导入） |
| 推荐引用方式 GB/T 7714 | 徐有宁. 抑制氮氧化物无烟燃煤技术及其应用[D]. 中国科学院研究生院. 2000. |
入库方式： OAI收割
来源：过程工程研究所
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