【作者】 吕元；

【导师】 肖云汉； 田文栋；

【作者基本信息】 中国科学院研究生院（工程热物理研究所） ， 工程热物理， 2012， 博士

【摘要】 我国每年通过煤矿通风瓦斯排入大气的甲烷约为130-170亿m3,煤矿通风瓦斯具有甲烷浓度低(<1%)、富集难、气量大等特点,传统的处理方式是直接排空,这造成了严重的能源浪费和温室气体排放。本文针对此现状,对煤矿通风瓦斯的蓄热式氧化过程进行了理论分析和数值模拟,在设计搭建的蓄热式氧化处理实验装置上,通过实验研究了装置的运行规律,并实现了装置结构进行了优化,并通过理论计算和分析,对实验数据进行比较验证。进行了放大装置的参数研究,分析选择了放大装置的热回收方式,并进行了技术经济性能分析。本文对蓄热体内的非稳态传热过程进行了理论分析,采用蓄热式换热理论进行了装置的自维持条件分析,得到了体积系数这一影响装置的自维持条件的关键参数。使用数值模拟的方法,建立耦合传热、流动、反应的周期性切换的简化物理模型,模拟通风瓦斯的蓄热热氧化过程,研究蓄热式氧化过程中的自维持特性。对最大处理量为1000Nm3/h的实验装置的蜂窝陶瓷蓄热室进行了设计计算和影响参数分析。在搭建的实验装置上,通过燃烧器产生高温烟气预热蓄热室的燃气启动方式,实现了装置在4小时内预热启动,使装置内温度场达到实验所需的理想温度场,并形成了装置常规的启动方式。通过热态调试,实现了装置单次自维持连续稳定运行超过200小时。对实验装置运行规律进行了研究,包括装置变工况运行性能、运行工况范围、各运行参数(风量、进气甲烷浓度、切换时间)的影响规律。实验结果显示,该装置可在入口气速1.23-0.62m/s、进气甲烷浓度0.45-0.9%范围内长期稳定运行,平均甲烷氧化率>95%。通过不同蓄热室结构的对比实验,实现了蓄热室结构的优化。结合实验数据,通过对实验装置能量平衡的计算分析,得到了装置理论运行的最低自维持甲烷浓度和通风量,并和实验结果进行了对比。进行了装置排烟温度、散热量、甲烷转化率对装置自维持最低甲烷浓度的敏感性分析。采用无量纲分析方法,计算了不同体积系数下装置的最低自维持甲烷浓度,与实验结果比较吻合。在实验研究的基础上,研究了大规模装置设计和运行的关键参数取值或取值范围。针对单台处理能力为10万Nm3/h的煤矿通风瓦斯处理装置,分析选择了热回收方式,并进行了技术经济性能分析。更多还原

【Abstract】 Every year, about130-170billion m3methane is emited though the ventilation air of coal mines in our country. Ventilation air methane (VAM) has the characteristics of low methane concentration, huge volume flow and hard to concentrate. The conventional method to deal with it is discharging into the atomsphere directly. It is a great pollution and has a significant greenhouse effect to the environment. According to the above situation, in this paper a theoretical study and a numerical simulation of the VAM regenerative oxidation were carried out, a laboratory device for VAM oxidation is designed and constructed. The operating rules is explored by experimental study and the structure is optimize. By theoretical analysis and numerical simulation, the experimental data was analysed. The key parameters for the large-scale VAM oxidation device are determined. The heat extraction measure of a large-scale device is researched. The production and economy of the item is analysed.In this research, the theoretical analysis of the unsteady heat transfer process in the regenerative body was carried out, base on the regenerative heat exchanging theory, the self-sustained condition was analysed, and the volume factor as an important parameter of the self-maintenance performance was obtained.The calculation and design are made for a oxidation bed with a capacity of1000Nm3/h which consists of honeycomb ceramic. On the laboratory device, the certain temperature fields needed of oxidation bed is achieved within4hours by fuel gas heating system. The general starting mode of the experiment is also determined.Through the hot commissioning, the steady self-maintenance running of the device is realized which can persist more than200hours. The operating rules of the device are studied, including the performance on variable working condition, the working range and the influence of the parameters (inlet velocity, CH4concentration, switching time). Experimental results show that the device can keep steady self-maintenance running within inlet velocity from0.62to1.23m/s, CH4concentration from0.45%to0.9%. The average oxidation rate is more than95%. By the comparative experiment of regenerator’s structures, the optimization of structures was attained.According to the experimental data, a calculation is made to prove the working condition by energy balance. The calculation results are close to the experimental data. The sensitivity of exhaust temperature, heat loss and oxidation rate to the floor level of CH4concentration for self-maintenance running is analysised. By the analysis of experimental results, the range of key parameters for the design and operation of demonstration device is determined.By dimensionless analysis, the floor levels of CH4concentration for self-maintenance running in various volume factor were calculated which was in accordance with the experimental results.Base on the experimental study, the value or the bound of the key parameters for large-scale VAM oxidation device are determined. The heat extraction measure of the large-scale device is researched. The production and economy of the item is analysed.更多还原