半焦掺混煤粉MILD燃烧的数值模拟及分析  

Numerical Simulation and Analysis of MILD Combustion of Residual Char Blended with Pulverized Coal

作　　者：熊彪[1] 李鹏飞 郭军军[1] 汪国庆 景旭亮 柳朝晖[1] 米建春[3] Xiong Biao;Li Pengfei;Guo Junjun;Wang Guoqing;Jing Xuliang;Liu Zhaohui;Mi Jianchun(State Key Laboratory of Coal Combustion,Huazhong University of Science and Technology,Wuhan 430074,China;State Key Laboratory of Coal-Based Low Carbon Energy,ENN Science and Technology Development Co.,Ltd.,Langfang 065001,China;State Key Laboratory of Turbulence and Complex Systems,College of Engineering,Peking University,Beijing 100871,China)

机构地区：[1]华中科技大学煤燃烧国家重点实验室,武汉430074 [2]新奥科技发展有限公司煤基低碳能源国家重点实验室,廊坊065001 [3]北京大学工学院湍流与复杂系统国家重点实验室,北京100871

出　　处：《燃烧科学与技术》2018年第5期407-412,共6页Journal of Combustion Science and Technology

基　　金：国家自然科学基金资助项目(91641122;51406001;51506065;51390494);国家重点研发计划资助项目(2016YFE0102500);湖北省重大科技创新计划资助项目(2015ACA051);新奥集团研发基金资助项目

摘　　要：研究了MILD燃烧方式下半焦(其挥发分小于4%,)掺混煤粉燃烧的着火、燃烧和燃尽特性.首先通过与国际火焰研究基金会(IFRF)的煤粉MILD燃烧实验数据对比,验证数值模拟方法的可行性.然后保持炉膛热功率和当量比不变,将半焦的掺混比例由0逐渐提高到40%,.研究发现,在MILD燃烧方式下,半焦掺混比例由0改变至40%,对炉内速度、温度、O_2浓度场和NO_x排放影响不明显,而对半焦燃尽率有显著影响.炉内反应氛围保持了MILD燃烧的优势,即温度峰值低且温度分布均匀,热力型和燃料型NO生成被抑制.在燃尽率方面,半焦掺混比例低于30%,时,燃料总体燃尽率始终高于90%,.减少半焦粒径或提高一次风温均可进一步提升燃尽率.This study investigates the ignition,combustion and burnout characteristics of MILD（the moderate or intense low-oxygen dilution）combustion of the residual char（i.e.,less than 4%, for the volatiles）blended with pulverized coal.The simulation is validated with the measurements of the IFRF（International Flame Research Foundation）.At the fixed mass flow rate of the furnace thermal input and equivalence ratio,the residual char blending ratio is gradually increased from 0 to 40%,.Results reveal that the residual char blending ratio has no significant effect on the flow field,temperature distributions,O2 volume fraction and NOx emission under the MILD combustion,while it plays a significant role on the burnout rate.The advantages of MILD combustion of residual char blended with pulverized coal are found,i.e.,semi-uniform temperature distribution with reduced peak temperature,suppressed thermal and fuel NO formation.For the burnout rate,when the residual char blending ratio is less than 30%,the fuel burnout rate is higher than 90%,.Moreover,it is found that the burnout rate can be further improved by reducing the particle size of residual char or by increasing the preheating temperature of primary air.

关 键 词：MILD燃烧 半焦 掺混燃烧 数值模拟 

分 类 号：TK11[动力工程及工程热物理—热能工程]