35 t/h纯燃超低挥发分碳基燃料预热燃烧锅炉运行特性研究  

Study on operation characteristics of a 35 t/h preheating combustion boiler with pure ultra-low volatile carbon-based fuels

作　　者：欧阳子区[1,2] 满承波 李增林 李诗媛 庞青涛[4] 朱建国 范志刚 刘敬樟[1] OUYANG Ziqu;MAN Chengbo;LI Zenglin;LI Shiyuan;PANG Qingtao;ZHU Jianguo;FAN Zhigang;LIU Jingzhang(Institute of Engineering Thermophysics,Chinese Academy of Sciences,Beijing 100190,China;University of Chinese Academy of Sciences,Beijing 100049,China;Dalian National Laboratory for Clean Energy,Dalian 116023,China;Shaanxi Coal Industry New Energy Technology Company Limited,Xi'an 710100,China)

机构地区：[1]中国科学院工程热物理研究所,北京100190 [2]中国科学院大学,北京100049 [3]中国科学院洁净能源创新研究院,辽宁大连116023 [4]陕西煤业新型能源科技股份有限公司,西安710100

出　　处：《华电技术》2020年第7期50-56,共7页HUADIAN TECHNOLOGY

基　　金：国家重点研发计划项目(2017YFB0602001);中国科学院战略性先导科技专项课题(XDA21040100);中国科学院青年创新促进会项目(2019148);西安市科技计划项目(201657SF/SF03);咸阳市科技计划项目(2016K02-31)。

摘　　要：低阶煤热解和气化后会产生热解半焦和气化残炭等超低挥发分碳基燃料,为解决超低挥发分碳基燃料着火稳燃难、燃尽难和污染物排放水平高等问题,在35 t/h工业煤粉锅炉上增加了预热燃烧器以及相关辅助系统,建成了35 t/h纯燃超低挥发分碳基燃料预热燃烧锅炉。在该锅炉上以神木烟煤、神木半焦和气化残炭为燃料进行试验,研究燃料种类、预热温度、二次风当量比和锅炉负荷对锅炉燃烧特性及污染物排放特性的影响。结果表明:3种燃料在35 t/h纯燃超低挥发分碳基燃料预热燃烧锅炉中都可以稳定燃烧,即使干燥无灰基挥发分为4.30%的半焦粉也能稳定地纯燃,表明预热燃烧技术具有很好的燃料适应性;3种燃料通过预热后进行燃烧,燃烧效率均超过99%;随着预热温度的增加炉膛的整体温度有所升高,NOx排放呈现先降低后增加的趋势,说明预热温度升高有利于预热后的燃料在炉膛中燃烧放热,预热温度为887℃时,NOx排放质量浓度达到最低值110.6 mg/m^3(标态,φ(O2)=9%);预热燃烧锅炉低负荷下的稳燃特性较好,负荷越低NOx排放质量浓度越低,最低可达108.0 mg/m^3(标态,φ(O2)=9%),体现了预热燃烧技术在稳燃、燃尽和低NOx排放上的优势。Ultra-low volatile carbon-based fuels,such as semi-coke and gasified residual carbon,are produced in pyrolysis and gasification of low-rank coal.A preheating combustor and auxiliary systems were installed on a 35 t/h coal-fired boiler combusting pure ultra-low volatile carbon-based fuels,so as to stabilize and enhance the burning of ultra-low volatile carbon-based fuels and lower the emission of pollutants.In the experiments carried out on the boiler,using Shenmu bituminous coal,Shenmu semi-coke and gasified residual carbon,effects of fuel type,preheating temperature,secondary air equivalent ratio and boiler load on combustion characteristics and pollutant emission were studied.The results showed that the three fuels can burn stably,and so can the pure semi-coke powder with dry ash-free volatilization fraction of 4.30%,which indicated the good fuel adaptability of the boiler.Been preheated,all the combustion efficiencies of the three fuels exceeded 99%.With the rise of preheating temperature,the overall temperature of the furnace increased,and the NOx emission mass concentration decreased first and then increased,indicating that the increase of preheating temperature was conducive to the combustion and heat release of preheated fuel in the furnace.When the preheating temperature was 887℃,the minimum NOx emission mass concentration was 110.6 mg/m3(standard state,φ(O2)=9%).The preheated boiler has good combustion stability under low loads.As boiler load is lower,the NOx emission decreased and bottomed at 108.0 mg/m3(standard state,φ(O2)=9%),which reflects the advantages of preheating combustion technology in stabilizing combustion,burnout and low NOx emission.

关 键 词：超低挥发分 碳基燃料 半焦 气化残炭 预热燃烧器 锅炉 NOX排放 燃烧效率 

分 类 号：TQ536[化学工程—煤化学工程]