骨料烘干煤粉燃烧器数值模拟及配风参数优化  

Numerical Simulation and Air Distribution Parameters Optimization for Pulverized Coal Burner of Aggregate Drying

作　　者：程海鹰 李旋[1,2] 张勇 CHENG Haiying;LI Xuan;ZHANG Yong(National Engineering Laboratory for Highway Maintenance Equipment,Chang'an University,Xi'an 710064;Zhejiang Prulde Electric Appliance Co.,Ltd.,Jinhua 321035;College of Mechanical and Electrical Engineering,Central South University,Changsha 410083)

机构地区：[1]长安大学公路养护装备国家工程实验室,西安710064 [2]浙江普莱得电器股份有限公司,金华321035 [3]中南大学机电工程学院,长沙410083

出　　处：《机械工程学报》2024年第20期289-299,共11页Journal of Mechanical Engineering

基　　金：国家自然科学基金(51665043);内蒙古自治区科技计划(2020GG0269)资助项目。

摘　　要：骨料烘干多采用燃油和燃气作为燃料,若采用煤粉作为燃料可显著降低运行成本。为有效控制煤粉燃烧行为良性发展,改善煤粉燃烧效率及降低NO_(X)排放,将分级配风技术应用于骨料烘干煤粉燃烧系统。以LB2000型骨料烘干设备为研究对象,建立骨料烘干煤粉燃烧系统计算模型,探索分级配风参数对燃烧效率和NO_(X)排放量的影响规律,并建立响应面控制模型,采用非支配排序遗传算法Ⅱ(Non-dominated sorting genetic algorithmⅡ,NSGA-Ⅱ)综合优化分级配风参数。研究结果表明:适当增加空气供给量不仅可促进煤粉充分燃烧且可保证NO_(X)排放处于较低水平;一定范围内增加燃尽风率,可使烘干筒高温区温度下降及其后半段温度提高,这有利于提升骨料烘干效果和质量,且在燃烧区形成局部缺氧的环境,NO_(X)的生成量降低;合理的空气分级深度可放缓煤粉燃烧的剧烈程度,二次风能改善煤粉与空气混合效果,进而促进煤粉燃烧充分。依据燃烧效率和排放特性,可确定过量空气系数合理取值范围为1.25~1.35,燃尽风率取值范围为0.6~0.7,空气分级深度取值范围为0.4~0.6。通过优化确定过量空气系数1.3375,燃尽风率0.6477,空气分级深度0.5999为最优参数。Oil and gas are mostly used as fuel for aggregate drying.Compared with oil and gas,the pulverized coal is also suitable for aggregate drying as the operating costs is dramatically reduced.In order to improve the combustion efficiency of pulverized coal and reduce NO_(X)emissions,the benign development of pulverized coal combustion behavior needed to be effectively controlled.So the grading air distribution was applied to the pulverized coal combustion system of aggregate drying.The LB2000 aggregate drying equipment was taken as a study case,and the numerical model of the pulverized coal combustion system for aggregate drying was established.The influence of graded air distribution parameters on the combustion efficiency and NO_(X)emissions was investigated.A response surface model was proposed,the graded air distribution parameters were comprehensively optimized by means of non-dominated sorting genetic algorithm II(NSGA-II).The results indicated that the pulverized coal combustion can be promoted and the NO_(X)emission can be regulated when the air supply is increased properly.The highest temperature zone is cooled down and the temperature of back of the drying drum is rose with better aggregate drying effect and quality,and an anoxic environment is formed in local area of the combustion zone,which reduced the amount of NO_(X)production with the increase of over-fire air within limits.Appropriate air staging depth is in favor to slowing down the combustion of pulverized coal.In addition,the mixing effect of pulverized coal and air can be improved by secondary air,so as to the full combustion of pulverized coal can be promote.The value ranges of the graded air distribution parameters are achieved according to the combustion efficiency and emission characteristics,which excess air coefficient is 1.25~1.35,over-fire air rate is 0.6~0.7,air staging depth is 0.4~0.6.The excess air coefficient is 1.3375,the over-fire air rate is 0.6477,and the air staging depth is 0.5999 through optimization.

关 键 词：煤粉燃烧 分级配风 燃烧效率 排放特性 骨料烘干 

分 类 号：TQ534[化学工程—煤化学工程]