摘要
本课题对矿井排风气体的利用进行了数值模拟研究,分别采用定向和换向操作流程。通过对固定床反应器一维定态模型和换向反应器一维动态模型的分析及其求解,结合并吸取相关文献研究流程的基础上,提出了带回热装置的三种工艺流程,分别为定态回热操作流程、定态尾部取热操作流程、尾部取热换向操作流程,为改善矿井排风气体自供热燃烧的操作条件提供了重要的流程设计思路。
本课题采用固定床反应器的一维定态数学模型,对矿井排风气体的自供热燃烧进行模拟计算。考察气体表观流速、原料气入口浓度、回热器面积、取热器面积、反应器长度等设计条件和操作条件对反应器的轴向气体温度分布和浓度分布的影响。采用换向反应器的一维动态数学模型,考察不同换向周期、不同气体表观流速、不同原料气入口浓度、不同反应器长度、不同的固相床层初始温度等设计和操作条件下,反应器的轴向气体温度分布和浓度分布情况,同时也考察了定态操作流程的单因素及双因素操作变量的可操作区域(当反应器固相床层的最高温度大于1300K时,定义反应器处于“飞温”状态；当反应器内的甲烷转化率低于99%时,定义反应器处于“熄火”状态),为工业实际生产提供依据。
此外,本课题还对两种定态操作流程在不同操作条件下进行了能量分析,主要考察能量损失率和能量利用率,对不同流程、不同操作条件下的能量进行了比较及分析。
In this subject,the numerical simulation of the utilization of mine exhaust gases is studied,thus putting to use orientation and reversal operational processes. The study is based on the the analysis and solutions of the one-dimensional steady state and dynamic mathematical model of catalytic reversal flow reactor (CRFR) and learning from the related literatures about the advantages of the processes, the three kinds of technology processes is proposed, which are heat recovery processes, steady state recovery heat process, steady state heat taking from the tail process, heat taking from the tail of CRFR process respectively. The proposal of three technology processes provides the important design ideas for improving the operation conditions for self-heating combustion.
The one-dimensional steady state mathematical model of fixed-bed reactor is established, which is used for simulation the self-heating combustion of mine exhaust gases. The operation parameters(the apparent flow rate of gas, the methane volume fraction of inlet gas, the regenerature area, the heat exchanger area, the length of reactor etc.) affect the axial gas temperature and concentration distribution. One-dimensional dynamic mathematical model of CRFR is adopted to determine the axial gas temperature and concentration distribution under different operation conditions(the reverse periods, the apparent flow rate of gas, the methane volume fraction of inlet gas, the length of reactor, the initial temperature of solid bed etc.). The one and two operation factors of the available operating region of fixed-bed reactor(the temperature run-away of solid bed reactor is the state when the average temperature of solid bed is over 1300K; the extinction is the state when the methane conversion rate is low than 99%) are researched, providing the basis for industry practical production.
In addition, the energy analysis of the two steady state processes are studied under different operating conditions, mainly on the energy loss rate and utilization rate, comparing and analyzing the energy under different processes and operating conditions.
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