一次风率对煤粉气流床气化-燃烧特性及NO_(x)排放影响的试验研究  

Experimental study on the gasification-combustion characteristics and nox emission characteristics of pulverized coal

作　　者：崔保崇 王肖肖 周必茂 谭厚章 熊小鹤 CUI Baochong;WANG Xiaoxiao;ZHOU Bimao;TAN Houzhang;XIONG Xiaohe(MOE Key Laboratory of Thermo-Fluid Science and Engineering,Xi'an Jiaotong University School,Shaanxi Xi'an,710049)

机构地区：[1]热流科学与工程教育部重点实验室(西安交通大学),陕西西安710049

出　　处：《电力科技与环保》2024年第2期133-141,共9页Electric Power Technology and Environmental Protection

基　　金：中国自然科学青年基金项目(22008192)。

摘　　要：煤粉气化-燃烧技术是实现燃煤锅炉超低负荷稳燃和低氮氧化物(NO_(x))排放的重要方式。为了揭示一次风率(λ_(1))对煤粉气化-燃烧特性及NO_(x)排放的影响。采用自主搭建的对冲气流床气化-燃烧系统,研究了λ_(1)对煤粉气化特性,燃料N转化和NO_(x)排放特性的影响,采用热重分析仪和化学吸附仪对气化半焦的反应性和孔隙结构进行分析。结果表明:λ_(1)的增加会提高气化炉温度,使气化炉出口CO和CH_(4)的浓度分别降低了2.67%和2.43%;促进了固定碳的转化,其转化率增加了17.28%;燃料N的转化率增加了13.50%,其中增加了向N_(2)的转化,但降低了向NH_(3)的转化。同时,λ_(1)增加使气化焦炭具有更发达的孔隙结构,比表面积增加了95.77 m^(2)/g,孔体积增加了2倍,改善了气化焦炭的燃烧特性。气化燃料进入燃烧室后,当λ_(1)高于0.25时,燃烧室主燃区内未生成NO。λ_(1)为0.35时,燃烧室出口的污染物排放最低,NO_(x)和CO分别为115.86 mg/Nm^(3)(@6%O_(2))和39.25 mg/Nm^(3)(@6%O_(2));此时燃烧效率最高,为99.68%。因此,一次风对煤粉气化燃烧特性和污染物排放具有显著的影响,控制合适的一次风量可以降低污染物排放的同时提升燃烧效率。Coal powder gasification combustion technology is an important way to achieve ultra-low load stable combustion and low nitrogen oxide(NO_(x))emissions in coal-fired boilers.To determine the effect of primary wind speed(λ_(1))on the gasification combustion characteristics and NO_(x) emissions of coal powder.A study was conducted on a selfbuilt counterflow fluidised bed gasification combustion systemλ.The reactivity and pore structure of the gasification semi-coke were analysed using a thermogravimetric analyser(TGA)and a chemical adsorption instrument to investigate the impact on the coal gasification characteristics,fuel nitrogen conversion and NO_(x) emission characteristics.The results indicate that the increase ofλ_(1) would increase the temperature of the gasifier,reducing the concentrations of CO and CH_(4) at the outlet of the gasifier by 2.67%and 2.43%,respectively;Promoted the conversion of fixed carbon,with a conversion rate increase of 17.28%;The conversion of fuel-N increased by 13.50%,with an increase in conversion to N_(2) but a decrease in conversion to NH_(3).Meanwhile,λ_(1) increasing the pore structure of gasification char resulted in a more developed pore structure,with an increase in specific surface area of 95.77 m^(2)/g and a 2-fold increase in pore volume,which improved the combustion characteristics.After the gasified fuel enters the combustor,whenλexceeds 0.25,no NO is generated in the main combustion zone of the combustor.When λ_(1)=0.35,the pollutant emissions at the combustor outlet are the lowest,with NO_(x) and CO at 115.86 mg/Nm^(3)(@6%O_(2))and 39.25 mg/Nm^(3)(@6%O_(2)),respectively;meanwhile,the combustion efficiency is the highest,with the value of 99.68%.Therefore,primary air has a significant effect on the combustion characteristics and pollutant emissions of pulverised fuel gasification.By controlling an appropriate amount of primary air,pollutant emissions could be reduced while improving combustion efficiency.

关 键 词：煤粉 气流床气化炉 气化燃烧 NO_(x)排放特性 

分 类 号：TK16[动力工程及工程热物理—热能工程] X7[环境科学与工程—环境工程]