煤矿通风瓦斯蓄热氧化过程研究

发布时间：2018-05-16 09:57

本文选题：通风瓦斯 + 蓄热氧化(逆流式热氧化)　；参考：《中国科学院研究生院（工程热物理研究所）》2014年博士论文

【摘要】：甲烷是一种重要的温室气体来源,其排放量仅次于二氧化碳,温室效应是二氧化碳的二十多倍。有效的处理和利用煤矿通风甲烷,具有温室气体减排和节约能源的重要意义。目前通风瓦斯处理技术应用最广的是采用蓄热氧化的方式实现低浓度甲烷的氧化处理。通风瓦斯蓄热氧化过程的参数影响分析是这一技术走向应用的基础。然而,实验规模和散热等约束条件使得参数影响的研究范围受到限制,实验分析的结果也不具有普遍的适用性。同时,面对通风瓦斯蓄热氧化装置的设计需求,实验和数值模拟研究难以满足快速的工程设计需要,也难预测设计参数变化带来的装置稳定运行范围变化问题。针对以上两方面的问题,本文对煤矿通风瓦斯蓄热氧化过程开展了实验、数值模拟和理论分析的研究,具体研究内容和结果如下： 1.针对通风瓦斯蓄热氧化过程的参数影响问题开展了无量纲化的实验参数分析研究。建立了通风瓦斯蓄热式热氧化实验系统以及低浓度甲烷氧化固定床反应器,同时建立了实验装置中蓄热式换热过程的无量纲分析模型。提出低浓度甲烷在氧化装置中氧化的基本条件,结合蓄热式换热过程的无量纲计算结果对实验中各个参数的影响进行了分析,结果表明和无量纲时间相关的切换时间对装置的影响较小,而与无量纲长度相关的气流速度对装置内温度分布的影响较大。 2.开展了通风瓦斯蓄热式热氧化装置的一维模型化研究。建立了通风瓦斯蓄热氧化装置的一维计算模型。利用开源的Matmol程序,基于线法对通风瓦斯蓄热氧化装置的运行过程进行了模拟计算,模拟结果和实验符合较好。计算结果表明,氧化装置的蓄热条件涉及气流流速、甲烷浓度、蓄热体结构等诸多因素,是装置能否稳定运行的关键。流速的影响存在有多重影响的机制,这一多重影响机制会使得通风瓦斯蓄热氧化装置在实际运行中既有通风量的下限也有通风量的上限。 3.开展了通风瓦斯蓄热式热氧化装置的三维建模研究。基于多孔介质的连续分布假设,利用Fluent软件的自定义标量方程等功能模块建立了通风瓦斯蓄热氧化过程的三维计算模型,利用这一计算模型研究了通风瓦斯蓄热氧化装置中流动分布、温度分布等问题。计算结果表明,蜂窝蓄热体区域的整流作用,使得工业装置设计中两端入口的结构对装置内流动分布的影响很小。散热会影响装置内的温度分布甲烷转化率,实验结构下的空腔有较小的气流混合作用。由于气流的滞留效应,装置切换时间缩短会降低装置的综合甲烷转化率,根据无量纲切换时间的计算,可以选择装置切换时间为60s-120s。 4.针对目前通风瓦斯蓄热氧化装置的设计需求,开展了基于蓄热式换热过程的蓄热氧化装置设计方法研究。提出一种蓄热氧化装置内最低稳定运行甲烷浓度的计算方法,并与部分实验结果进行了比较验证,计算模型的预测结果与实验符合较好。基于这一方法进一步计算了装置内通风量范围、蓄热体的需求量等参数。计算结果表明装置存在主要由散热决定的通风量下限以及由蓄热性能决定的通风量上限。烟气分流计算结果和稳定运行试验运行结果表明,本文提出的设计方法可以用于工业装置的设计。
[Abstract]:Methane is an important source of greenhouse gas, its emission is second to carbon dioxide, and the greenhouse effect is more than 20 times of carbon dioxide. It is of great significance to effectively deal with and utilize methane in coal mine. It is of great significance to reduce the emission of greenhouse gases and save energy. The oxidation treatment of low concentration methane. The parameter influence analysis of ventilation gas storage and oxidation process is the basis for the application of this technology. However, the experimental scale and heat dissipation restrict the scope of the study on the influence of the parameters, and the results of the experimental analysis are not universally applicable. At the same time, the heat storage and oxidation of ventilation gas is not available. The design requirements of the device, the experimental and numerical simulation research are difficult to meet the needs of the rapid engineering design, and it is difficult to predict the change of the stable operating range of the device caused by the change of the design parameters. In this paper, the experiment, numerical simulation and theoretical analysis of the coal mine ventilation gas storage and oxidation process are carried out in this paper, and the research on the numerical simulation and theoretical analysis is carried out. The content and results of the study are as follows:
1. the dimensionless experimental parameter analysis was carried out for the parameter influence of the ventilation and gas thermal storage oxidation process. A thermal oxidation experimental system of ventilation gas storage and a low concentration methane oxidation fixed bed reactor were established, and a non dimensional analysis model of the regenerative heat transfer process in the experimental device was established. The basic conditions for the oxidation of alkane in the oxidation unit are analyzed with the dimensionless calculation results of the regenerative heat transfer process. The results show that the influence of the switching time related to the dimensionless time has little effect on the device, and the influence of the airflow velocity related to the dimensionless length on the temperature distribution in the device is more than that of the dimensionless length. Big.
2. one dimension model of the thermal oxidation device of ventilation gas storage is carried out. One dimension calculation model of the ventilation gas regenerative oxidation device is set up. The operation process of the ventilation gas regenerative oxidation device is simulated with the open source Matmol program. The simulation results are in good agreement with the experiment. The calculation results show that oxygen is in good agreement with the experiment. The regenerative conditions of the device involve the flow velocity, the methane concentration, the structure of the regenerator and so on. It is the key to the stable operation of the device. The influence of the flow rate has a mechanism of multiple effects. This multi effect mechanism will make the ventilation and gas storage oxidation device have the lower limit of ventilation and the upper limit of ventilation in the actual operation.
3. the three-dimensional modeling study of the thermal oxidation device of ventilation gas storage is carried out. Based on the hypothesis of the continuous distribution of porous media, a three-dimensional calculation model of the heat storage and oxidation process of ventilation gas is established by using the function module of the custom scalar equation of Fluent software, and the flow of the ventilation and gas storage heat oxidation device is studied by this calculation model. The calculation results show that the rectifying effect of the area of the honeycomb regenerator makes the structure of the inlet at the two ends of the industrial device have little effect on the flow distribution in the device. The heat dissipation will affect the temperature distribution of methane in the device, and the cavity in the experimental structure has a small mixing effect on the air flow. When the switching time is shortened, the total methane conversion rate of the device will be reduced. According to the calculation of the non dimensional switching time, the switching time of the device can be selected as 60s-120s..
4. the design method of regenerative oxidation device based on regenerative heat transfer process is carried out in view of the design requirements of the current ventilation and gas regenerative oxidation device. A calculation method for the minimum stable operation of methane concentration in the regenerative oxidation unit is proposed, and the results are compared with the experimental results. The prediction results and experiments of the calculated model are also carried out. This method is better. Based on this method, the parameters of the ventilation range, the demand of the regenerator are further calculated. The calculation results show that there is a lower limit of ventilation determined mainly by heat dissipation and the upper limit of ventilation determined by the regenerative performance. The results of the calculation of the flue gas diversion and the running results of the stable operation show that this paper is proposed in this paper. The design method can be used in the design of industrial equipment.

【学位授予单位】：中国科学院研究生院（工程热物理研究所）
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TD712

【参考文献】