混燃煤气气氛下NO_x排放特性与建模预测  

Characteristic of NO_x emissions in co-firing gases and modeling prediction

作　　者：梁占伟[1] 陈鸿伟[1] 杨新[1] 许文良[1] 赵争辉[1] LIANG Zhanwei;CHEN Hongwei;YANG Xin;XU Wenliang;ZHAO Zhenghui(School of Energy,Power and Mechanical Engineering,North China Electric Power University,Baoding 071003,Hebei,China)

机构地区：[1]华北电力大学能源动力与机械工程学院,河北保定071003

出　　处：《化工进展》2017年第11期4265-4271,共7页Chemical Industry and Engineering Progress

基　　金：河北省自然科学基金项目(E2016502058)

摘　　要：以300MW煤/气混燃锅炉为研究对象,理论计算了高炉煤气、焦炉煤气及煤粉的热量混燃比对烟气量的影响特性,对混燃煤气协同分级配风条件下的NO_x排放特性进行了优化实验研究,利用实验数据建立了NO_x排放浓度的预测模型。结果表明:当高炉煤气与焦炉煤气配比为0.3时产生的理论烟气量与纯然煤工况相当;混燃高炉煤气使得炉膛温度温差减小,有利于控制NO_x排放;随着高炉煤气热量混燃比和分离燃尽风率的增加NO_x排放浓度逐渐降低,而飞灰含碳量逐渐增加。综合衡量NO_x排放浓度和飞灰含碳量,高炉煤气(BFG)与焦炉煤气(COG)的最佳热量混燃比配比应低于1.3,最佳的分离燃尽风率为24%。通过对比所建立的3种NO_x排放预测模型,发现遗传算法优化的BP神经网络模型具有较高的预测精度,能够准确表达锅炉输入参数和输出参数的非线性关系。The effect of heat adding rates of blast furnace gas,coke oven gas and coal on flue gas volume was theoretically analyzed in a300MW boiler co-firing coal with gases.Moreover,the optimization test of NOx emissions was conducted under the condition of heat adding rates and air staging,and the prediction models of NOx emissions was established based on the experimental data.The result showed that the theoretical flue gas volume of coal co-fired with gases was equal to that of pure coal when the ratio of blast furnace gas and coke oven gas was0.3.The co-combustion of blast furnace gas can decrease the difference of furnace temperature,being beneficial to control the NOx emissions.The NOx emissions concentration decreased and the unburned carbon in fly ash increased gradually with the increase of heat adding rate of blast furnace gas and the ratio of separated overfire air.By comprehensive measurement of the NOx emission and carbon content of fly ash,the optimal ratio of heat adding rate between blast furnace gas and coke oven gas was1.3,and the optimal ratio of separated overfire air was24%.The comparative analysis of the three models indicated that the GABP model had the highest prediction accuracy and could accurately describe the nonlinear relationship between the input and output parameters of boiler.

关 键 词：煤燃烧 分级配风 NOX排放 模型 神经网络 

分 类 号：TK229.2[动力工程及工程热物理—动力机械及工程]