半焦空气分级燃烧NOx排放试验研究  

Experimental study on NOx emission of semi-coke air-staged combustion

作　　者：李慧 杨石 周建明 LI Hui;YANG Shi;ZHOU Jianming(China Coal Research Institute Company of Energy Conservation,Beijing 100013,China;National Coal Resource High Efficient Mining and Clean Utilization,Beijing 100013,China;National Key Lab of Energy and Coal High Utilization,Energy Saving and Emission Reduction Technology and Equipment,Beijing 100013,China)

机构地区：[1]煤科院节能技术有限公司,北京100013 [2]煤炭资源高效开采与洁净利用国家重点实验室,北京100013 [3]国家能源煤炭高效利用与节能减排技术装备重点实验室,北京100013

出　　处：《洁净煤技术》2020年第2期109-114,共6页Clean Coal Technology

基　　金：天地科技股份有限公司科技创新创业资金专项项目重点项目(2018-TD-ZD001)。

摘　　要：半焦是低阶煤经低温热解后的产物,其中半焦粉与煤粉工业锅炉常用煤种烟煤相比价格低廉。若能将半焦粉用作煤粉工业锅炉的燃料,既可拓宽煤粉工业锅炉的适用燃料范围,又可增强煤粉工业锅炉的市场竞争力。由于半焦挥发分低、固定碳高,实现其着火和稳定燃烧需要更高的温度,同时,降低NOx初始排放也是一个技术难题。为了实现半焦在煤粉工业锅炉中的稳定燃烧及NOx排放的降低,采用两段式滴管炉开展半焦空气分级燃烧NOx排放规律研究。笔者对半焦空气不分级燃烧NOx排放规律进行了研究,主要探究了主燃区温度(1 000~1 400℃)及过量空气系数的影响,为后续空气分级燃烧降低NOx的效果提供对比依据。半焦空气分级燃烧试验主要研究了主燃区温度(1 000~1 400℃)及二次风比例(0.4~0.8)的影响,并从燃尽率、NOx减少比例、灰样微观孔隙和形貌等方面进行论证,试验结果表明,在空气不分级燃烧条件下,即燃尽风配风比例为0时,随着主燃区温度升高,NOx排放浓度随之迅速升高;随着过量空气系数增加,NOx浓度先迅速增加,过量空气系数大于1.15时,NOx浓度增速变缓;在空气分级燃烧中,相同主燃区温度条件下,二次风比例由高到低变化时,NOx排放呈先迅速下降后缓慢回升的变化趋势,燃尽率先快速升高而后趋于平缓。二次风比例为0.56时(即燃尽风率为0.39),燃尽率达90%,NOx排放浓度降至最低,为120 mg/m^3以下,此时是试验条件下的最佳二次风比例。Semi-coke is the product of low-rank coal pyrolysis at low temperature. The price of pulverized semi-coke is lower than that of bituminous coal which is the commonly used in industrial pulverized coal boiler. If semi-coke can be used as the fuel of industrial pulverized coal boiler,the applicable fuel range of the coal-fired industrial boiler will be widen. Besides,the market competitiveness of coal-fired industrial boiler can be enhanced. Because of the low volatile content and a high fixed carbon content,semi-coke needs a higher temperature for ignition and steady combusiton. What’s more,the decrease of NOxemission is a also a technical problem. The NOx emission properties of semi-coke air-staged combustion was studied in two-stage drop-tube furnace to realize steady combustion in pulverized coal industrial boiler and low NOxemission of semi-coke. In this paper,the NOxemission law of semi coke air non-staged combustion was studied.The influence of fuel-rich zone temperature( 1 000-1 400 ℃) and excess air coefficient( 1.0-1.3) were explored to give a comparison with the following air-staged combustion experiment. In semi-coke air-staged combustion experiment,the influence of the fuel-rich zone temperature( 1 000-1 400 ℃) and the ratio of secondary air( 0.4-0.8) were explored. Besides,the burn-out rate,NOx decrement rate and microscopic pore structure and morphology of air-graded combustion ash were analyzed to reach a comprehensive conclusion. It can be concluded from the non-staged combustion experiment that under the condition of air non staged combustion,and when the ratio of exhaust air to air distribution is 0,the NOxemission increases rapidly with the fuel-rich zone temperature increasing. When the excess air coefficient increases,the NOxemission increases rapidly first,and then the increase becomes slowly when excess air coefficient is over 1.15.It can be concluded from the air-staged combustion experiment that when the ratio of secondary air changes from high to low under the same temperature of th

关 键 词：半焦 空气分级燃烧 NOx 两段式滴管炉 配风比例 

分 类 号：TK229[动力工程及工程热物理—动力机械及工程]