摘要
为了建立Φ80mm×3000mm下行夹带流煤气化反应器模型,以胜利褐煤为原料,在该反应器中进行了N2、O2、H2O、H2O+O2气氛下800℃/900℃气化实验,研究了流场分布、主要反应发生区域,并结合反应机理和缩合模型推导了不同速控步/气化气氛下C-O2氧化和C-H2O气化速率方程。结果发现,实验条件下,喷嘴附近的射流区及其周围的回流区仅占反应器高度的5%,气相主要以平推流流动;热解和燃烧反应同时发生,反应器分为热解燃烧区和气化区;气膜扩散控制下的C-O2氧化速率方程和化学反应控制时C-H2O气化速率方程与实验数据吻合较好;相对H2O气氛,H2O+O2气氛下C-H2O气化反应的表观气化反应速率常数明显较大,尤其在高温下,建模时需分别考虑H2O和H2O+O2气氛下气化速率。这主要是由于氧化反应的开孔/扩孔作用使碳颗粒微孔数量、比表面积、孔容增加,促进了C-H2O气化反应。采用MATLAB编程拟合求解模型中未知参数和模型,对12组实验(60个数据点)进行预测,85%预测值误差小于20%,70%预测值误差小于10%。对褐煤转化率的预测,75%预测值误差小于4.6%。建立的反应器模型误差较小,为反应器设计和放大奠定基础。
Shengli lignite was gasified at 800℃/900℃ under N2, O2, H2O, H2O+O2 atmospheres in a simulated entrained-flow reactor(Φ80 mm×3000 mm). And kinetics of main reactions & flow characteristics of gas/solid were discussed, in order to build coal gasification model. The results showed that: the gas phase flow was divided into 3 zones, jet zone, recirculation zone and downstream zone, but the height of jet zone and recirculation zone only was 5% of that of reactor and could be neglected;pyrolysis and combustion occur simultaneously;the oxidation reaction(OR) and the steam gasification reaction(SGR) were controlled by membrane diffusion and chemical reaction respectively, and the rate equations derived from shrinking core model and reaction mechanism were in good agreement with experimental data. Moreover, the apparent rate constant of SGR in H2O+O2 atmosphere was obviously larger than that in H2 O atmosphere, especially at high temperature. It might be caused by that OR could produce microspores and develop mesopores to promote SGR rate, i.e. OR and SGR had synergistic effect.The model built was solved by MATLAB and employed to predict 12 groups of experiments(60 data points). And the predicted values were in good agreement with the experimental values, with the error of less than 20% for 85% predicted values and less than 10% for 70% predicted values. For the prediction of lignite conversion rate, the predicted values were in perfect agreement with the experimental values, with the error of less than 4.6% for 75% predicted values.
作者
程相龙
郭晋菊
张海永
孙加亮
张延兵
宋成建
CHENG Xianglong;GUO Jinju;ZHANG Haiyong;SUN Jialiang;ZHANG Yanbing;SONG Chengjian(School of Materials and Chemical Engineering,Henan University of Urban Construction,Pingdingshan 467036,Henan,China;Henan Province Engineering Laboratory of Coal-Salt Resources Efficient Utilization,Henan University of Urban Construction,Pingdingshan 467036,Henan,China;School of Chemical and Environmental Engineering,China University of Mining and Technology(Beijing),Beijing 100083,China)
出处
《化工进展》
EI
CAS
CSCD
北大核心
2020年第1期119-128,共10页
Chemical Industry and Engineering Progress
基金
国家自然科学基金(21506251)
河南城建学院青年骨干教师选拔及资助项目(20171015)
煤盐资源高效利用河南省工程实验室(河南城建学院)开放基金
关键词
气流床
协同作用
流动特点
气膜扩散
反应速率
模型
entrained-flow reactor
synergistic action
flow characteristics
membrane diffusion
dynamics
model
