燃烧温度对神华烟煤加压燃烧过程中C/N转化特性的影响  

Effect of combustion temperature on pressurized combustion and C/N transformation characteristics of Shenhua bituminous coal

作　　者：张屿 杜尚斌 张文达[1] 赵义军[1] 孙绍增[1] ZHANG Yu;DU Shangbin;ZHANG Wenda;ZHAO Yijun;SUN Shaozeng(School of Energy Science and Engineering,Harbin Institute of Technology,Harbin150001,China)

机构地区：[1]哈尔滨工业大学能源科学与工程学院,黑龙江哈尔滨150001

出　　处：《洁净煤技术》2022年第8期43-49,共7页Clean Coal Technology

基　　金：国家重点研发计划"政府间国际科技创新合作"基金资助项目(2019YFE0100100-14);中央高校基本科研业务费专项资金资助项目(2022ZFJH004)。

摘　　要：加压O_(2)/CO_(2)燃烧技术是一种可以实现CO_(2)高效捕集的新型燃烧技术。为探究煤粉在加压O_(2)/CO_(2)气氛下的燃烧特性和污染物释放特性,采用加压沉降炉试验系统在0.9 MPa压力下对神华烟煤的加压燃烧(燃烧时间0.3 s)特性和N元素迁移释放特性进行研究。通过在线测量手段分析了O_(2)/CO_(2)气氛下,温度(1073~1273 K)对燃烧过程中气相产物CO、N_(2)O以及NO生成规律的影响。通过离线表征手段分析了温度对燃烧残炭物理化学结构变化的影响。结果表明,煤粉加压燃烧过程中,升高燃烧温度会导致煤中燃料N的气相NO_(x)转化率先升高后降低,相比N_(2)O,升高燃烧温度对NO释放的影响较弱,煤中燃料N向气相NO_(x)转化主要由N_(2)O决定。煤粉加压O_(2)/CO_(2)燃烧过程中,CO和NO浓度随燃烧温度的升高逐渐减小和增大,而N_(2)O释放随燃烧温度的升高先增后减。燃烧温度1273 K时,CO、NO、N_(2)O体积分数分别达到363.5×10^(-6)、10.2×10^(-6)和6.8×10^(-6)。FTIR结果表明,煤粉颗粒表面O—C=O结构含氧官能团比C—OH结构含氧官能团具有更高的燃烧反应活性。燃烧温度从1073 K升至1273 K时,C—O相对含量变化较小,O—C=O、C=O、C—H相对含量分别减小了1%、1%和7%,而C=C/C—C相对含量增加了7%。表明加压燃烧过程中升高温度会促进C—H结构快速消耗,同时提升残炭的芳香程度。1273 K时,煤粉燃烧残炭表面以N-5、N^(-6)形式赋存的N元素相对含量分别减少7%以及增加5%。加压O_(2)/CO_(2)燃烧过程中释放的NO_(x)含氮前驱物主要来源于焦炭中固有的N-Q结构,其相对含量变化较小。Pressurized O_(2)/CO_(2) combustion technology is a new combustion technology that can achieve efficient CO_(2) capture.In order to explore the combustion and pollutant emissions characteristics of pulverized coal in a pressurized O_(2)/CO_(2) atmosphere,the pressurized combustion(residence time is 0.3 s)and N transformation characteristics of Shenhua bituminous coal were investigated by a pressurized drop tube furnace(PDTF)experimental system at a pressure of 0.9 MPa.Effect of combustion temperature(1073-1273 K)on the formation rules of gaseous products(CO,N_(2)O and NO)in the O_(2)/CO_(2) combustion process was analyzed by online measurement,and effect of combustion temperature on the physical and chemical structure of combustion residues was analyzed by off-line characterization.In the pressurized combustion process of pulverized coal,the increase of combustion temperature causes the conversion rate of fuel nitrogen to NO_(x) in coal to increase first and then decrease.In the combustion temperature range of 1073-1273 K,compared with N_(2)O,the increase of combustion temperature has less effect on NO release,and the conversion of fuel nitrogen in coal to gas-phase NO_(x) is mainly determined by the generation of N_(2)O.In the process of coal pressurized O_(2)/CO_(2) combustion,the concentrations of CO and NO gradually decrease and increase with combustion temperature,while the release of N_(2)O increases first and then decreases with combustion temperature.At 1273 K,the emission concentrations of CO,NO and N_(2)O reach 363.5×10^(-6),10.2×10^(-6)and 6.8×10^(-6),respectively.The FTIR results show that the oxygen-containing groups of the O-C=O structure on the surface of pulverized coal particles have higher combustion reactivity than C-OH structure.As the combustion temperature increases from 1073 K to 1273 K,the relative content of C-O dose not change much,and the relative contents of O-C=O,C=O and C-H decrease by 1%,1%and 7%,respectively,while the relative content of C=C/C-C increases by 7%.It shows that the

关 键 词：加压燃烧 神华烟煤 氮转化 焦炭结构 加压沉降炉 

分 类 号：TQ53[化学工程—煤化学工程] TK114[动力工程及工程热物理—热能工程]