不同挥发分含量煤种与热解半焦混燃热态试验研究  

Thermal experimental study on co-combustion of pyrolysis semi-char and coal with different volatile content

作　　者：陈登科 闫永宏[1] 彭政康 王兴益 孙刘涛 孙锐[1] CHEN Dengke;YAN Yonghong;PENG Zhengkang;WANG Xingyi;SUN Liutao;SUN Rui(School of Energy Science and Engineering,Harbin Institute of Technology,Harbin 150001,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》2021年第1期281-290,共10页Clean Coal Technology

基　　金：国家重点研发计划资助项目(2017YFB0602002)。

摘　　要：半焦是低阶煤经低温热解后的产物,着火和实现稳定燃烧较原煤需更高温度,为拓展其在电厂动力用煤等领域的应用,有必要引入一些易燃高挥发分煤种作为混燃燃料;同时国内外关于混煤燃烧研究多是基于小型试验台和数值模拟,而非中试规模的试验系统。基于此,在350 k W热态试验炉上开展了不同挥发分煤种(褐煤、烟煤、次烟煤)与神木热解半焦混燃热态试验研究。通过测量燃烧器下游主燃区不同轴向位置、径向位置处炉膛温度以及O_2、CO、CO_2、NO_x等气体成分浓度,研究掺混煤质变化对混合燃烧(半焦质量掺混比50%)的着火特性以及NO_x生成影响。结果表明:混合燃料浓侧煤粉射流的着火优于淡侧,O_2消耗及燃烧产物生成也主要集中在浓侧;随着混合煤质V_(daf)增加,混煤射流着火距离减小,燃点下降,燃烧器出口与稳定燃烧区之间的距离随之缩短;主燃区出口截面处,褐煤+半焦、烟煤+半焦、次烟煤+半焦混合射流中心的NO_x浓度分别为473、462、532 mg/m~3(6%O_2下,下同),对于褐煤+半焦、烟煤+半焦混合射流NO_x浓度差值较小,仅为11 mg/m~3。综合考虑着火距离、燃烧强度和主燃区NO_x排放量,适合较大比例混合热解半焦(半焦掺混比50%)混燃煤质的V_(daf)不宜低于16%。Semi-char is the product of low-rank coal pyrolysis at low temperature,which requires higher temperature for its ignition and stable combustion than raw coal.In order to expand semi-char′s application in power plants and other fields,it is necessary to introduce some combustible and high-volatile coals as co-combustion fuel.On the other hand,domestic and foreign research on blended coal combustion is mostly based on small-scale test benches and numerical simulations,rather than pilot scale test systems.Therefore,the thermal experimental study was conducted to investigate the influence of different volatile content(lignite,bituminous coal,sub-bituminous coal)on the mixed combustion with Shenmu pyrolysis semi-char in a 350 kW pulverized coal-fired pilot-scale furnace.The furnace temperature at different axial and radial positions,and concentrations of gaseous species(O 2,CO,CO 2 and NO x)at furnace axis were measured in the primary combustion zone to study the effects of blended coal quality change on ignition,NO x emission and burnout characteristics for co-combustion(the quality blend ratio of semi-char is 50%).The research results show that the ignition and combustion of the fuel-rich jet is better than that of the fuel-poor jet,and the O 2 consumption and flue gas generation are also mainly concentrated on the fuel-rich jet.With the increase of dry ash-free volatile(V daf)content in blended coal,the stand-off distance of blended coal decreases,the ignition temperature reduces,and the distance between the burner outlet and the stable combustion zone is shortened.At the exit section of the primary combustion zone,the NO x emission concentration of the mixed jet for lignite+semi-coke,bituminous coal+semi-coke,and sub-bituminous coal+semi-coke are respectively 473,462 and 532 mg/m 3(under 6%O 2,the same below),while the difference of NO x concentration of lignite/semi-char and bituminous/semi-char jet is only 11 mg/m 3.Considering the ignition distance,combustion intensity and NO x emission from the primary combu

关 键 词：热解半焦 混合燃烧 挥发分 着火特性 NO_X排放 

分 类 号：TK22[动力工程及工程热物理—动力机械及工程] TQ534[化学工程—煤化学工程]