摘要
高压气化炉内煤粉的着火特性对煤粉烧嘴和气化室的设计与运行调控具有重要意义。笔者采用加压热重分析法对3个煤样的着火特性进行研究,根据升温过程中的能量守恒原理和谢苗诺夫着火理论提出了一种新的处理PTG曲线求取着火温度的拐点法,并与传统经验切线法进行对比;讨论了压力、氧气体积分数、升温速率、挥发分和颗粒粒径对着火温度的影响。研究结果表明,煤粉着火温度区间为从初始着火温度(Ti)到极限着火温度(Tig),环境换热条件所决定的切点位置是唯一定解条件,高温工业炉高加热速率对应的为极限着火温度;与常压条件下相比,加压下固定床煤粉的着火为异相着火,着火温度随挥发分的增加而略有增加;在0.1~1.0 MPa和3~5 MPa的压力范围内,随压力的升高,着火温度下降,且比常压下低很多,虽然在1~3 MPa的着火温度略有增加;氧气体积分数对着火温度的影响规律与常压的类似,随氧气体积分数的增加,着火温度降低;虽然加压条件下煤粉的快速反应,拐点法与切线法得到的着火温度相近,但切线法无法响应环境条件的变化,且常压下,经验的切线法无法给出令人满意的结果。
It is very important to study the ignition characteristics of pulverized coal for the design and operation of nozzle and chamber in a pressurized gasifier.In this paper,the ignition characteristics of three types of coal sample were studied by using pressurized thermogravimetry.According to the principle of energy conservation in the process of heating up and Semenov’s TET theory,a novel method by processing PTG curve and obtaining ignition temperature,namely the inflection point method was proposed,which was compared with the empirical tangent method.The influences of pressure,oxygen concentration,heating rate,volatile content and particle sizes were discussed.The results show that the ignition temperature range of pulverized coal is from the initial ignition temperature( Ti) to the ultimate ignition temperature( Tig),and the location of tangential point determined by the environmental heat transfer conditions is the only definite condition.The high heating rate of high-temperature industrial furnaces corresponds to the ultimate ignition temperature;during the pressurized combustion of pulverized coal in fixed bed,heterogeneous ignition occurs,and the ignition temperature increases slightly with the increase of volatile content;in the pressure ranges of 0.1-1.0 MPa and 3-5 MPa,the ignition temperature decreases with the increase of pressure,which is much lower than that under atmospheric combustion,but increases slightly at the pressure range of 1-3 MPa.The effect of oxygen volume fraction on ignition temperature is similar to that of atmospheric pressure.With the increase of oxygen volume fraction,the ignition temperature decreases.Although the quick oxidation of pulverized coal under pressure and the ignition temperature obtained by the inflection point method is close to that obtained by the empirical tangent method,the tangent method cannot respond to the change of environmental conditions,and the empirical tangent method cannot give satisfactory results under normal pressure.
作者
傅培舫
龚雪琦
张斌
刘洋
龚宇森
许天瑶
FU Peifang;GONG Xueqi;ZHANG Bin;LIU Yang;GONG Yusen;XU Tianyao(State Key Laboratory of Coal Combustion,School of Energy and Power Engineering,Huazhong University of Science and Technology,Wuhan 430074,China)
出处
《洁净煤技术》
CAS
2020年第1期59-64,共6页
Clean Coal Technology
基金
国家自然科学基金资助项目(51576082)
国家重点研发计划资助项目(2018YFB0604100-2)。
关键词
煤粉燃烧
着火特性
加压燃烧
高压气化炉
Pulverized coal combustion
ignition characteristics
pressurized combustion
pressurized gasifier
