摘要
为实现煤化工固废——气化细粉灰的清洁高效利用,采用先进的煤粉自预热燃烧技术,在30 kW固体碳基燃料预热无焰燃烧试验平台上,针对不同预热温度、不同预热燃烧器当量比下的烟煤经循环流化床气化后,细粉灰中氮的转化及NO_(x)排放特性进行试验研究。结果表明,气化细粉灰能在该试验系统上实现稳定的无焰燃烧。预热可明显改善气化细粉灰的燃烧特性改善具有重要作用。几乎全部挥发分氮在预热燃烧器内的强还原性气氛下提前脱除,主要向N_(2)、NH3与HCN三种含氮物质转化,焦炭氮为后续燃烧中NO_(x)的主要来源。预热温度对预热过程中煤氮向N_(2)的转化率影响显著,预热燃烧器空气当量比直接关系煤氮向N_(2)和NH3的转化率,且与焦炭氮析出情况密切相关。预热温度和预热燃烧器空气当量比对NO_(x)排放浓度及燃料氮向NOx转化率的影响效果差别明显。在预热温度为902℃、预热燃烧器空气当量比为0.45的条件下,NO_(x)排放浓度和燃料氮向NOx转化率最低,分别为83.02 mg/m^(3)(6%O_(2))和5.94%。
To achieve the clean and efficient utilization of the coal gasification fly ash,experimental studies which adopted advanced selfpreheating combustion technology were carried out on a 30 kW preheating flameless combustion test rig for solid carbon-based fuel.Fuel-N transformation and NO_(x) emission characteristics from fine ash of bituminous coal gasification fly ash under different preheating temperatures and primary air equivalence ratio were discussed.The results show that the coal gasification fly ash can achieve stable flameless combustion on this experimental system.The combustion characteristics of coal gasification fly ash are greatly improved after preheating.Almost all volatile-N is removed in advance under the strong reducing atmosphere in the self-preheated burner,and is mainly converted to three nitrogen-containing substances:N_(2),NH3 and HCN.Thus char-N is the main source of NO_(x) emission in subsequent combustion.During the preheating progress,preheating temperature has an obvious effect on the conversion of fuel-N to N_(2),while the primary air equivalence ratio mainly affects the conversion rate of fuel-N to N_(2),NH3 and the nitrogen precipitation from char-N.The effects of preheating temperature and primary air equivalence ratio of preheated burner on NO_(x) emission concentration and conversion rate of fuel-N to NO_(x) are obviously different.The concentration of NO_(x) emission and conversion rate of fuel-N to NO_(x) both reach the lowest value when the preheating temperature is 902℃ and the primary air equivalence ratio of preheated burner is 0.45,which are 83.02 mg/m^(3)(6% O_(2))and 5.94%,respectively.
作者
丁鸿亮
欧阳子区
DING Hongliang;OUYANG Ziqu(School of Engineering Science,University of Chinese Academy of Sciences,Beijing 100049,China;Institute of Engineering Thermophysics,Chinese Academy of Sciences,Beijing 100190,China)
出处
《洁净煤技术》
CAS
北大核心
2021年第3期70-80,共11页
Clean Coal Technology
基金
国家重点研发计划资助项目(2017YFB0602001)
中国科学院青年创新促进会项目(2019148)。
关键词
气化细粉灰
循环流化床
预热
无焰燃烧
煤氮转化
NOX排放
coal gasification fly ash
circulating fluidized bed
preheat
flameless combustion
fuel-N transformation
NO_(x) emission
作者简介
丁鸿亮(1996-),男,内蒙古赤峰人,博士研究生,研究方向为煤炭清洁高效利用。E-mail:dinghongliang@iet.cn;通讯作者:欧阳子区,副研究员,博士,研究方向为洁净煤燃烧技术。E-mail:ouyangziqu@iet.cn。
