瓦斯生化降解反应器内气泡动力学行为特性

发布时间：2018-03-31 17:30

本文选题：甲烷氧化菌悬浮液　切入点：气泡动力学　出处：《中国矿业大学》2017年硕士论文

【摘要】：在煤矿开采过程中,以游离或附着状态存在于煤体或围岩中的甲烷气体会被稀释排空以确保安全生产。然而,这不仅造成了能源的浪费,更将加剧温室效应。甲烷是仅次于二氧化碳的第二大温室气体,但是甲烷促使气候变暖的潜力要比二氧化碳大25~30倍。近年来,随着生物工程和环境工程等技术领域的快速发展,采用生化转化技术进行煤矿瓦斯治理已成为一个极具前瞻性和挑战性的新兴研究领域。本文以甲烷氧化菌生化降解瓦斯中含有的甲烷为研究背景,系统地研究了多尺度生化反应器内甲烷氧化菌菌悬液中的气泡动力学特性,以及多尺度生化反应器条件下甲烷和氧气混合气的传输特性。本文采用可视化的实验方法,通过改变气体流量、菌液浓度、毛细管内径、朝向、中心距等参数,在不同尺度的生化反应器内,研究了气泡在生长、脱离、涌入、聚并和上升运动等过程中的动力学行为。实验的研究结果为不同尺度的生化反应器中布气器的设计和生化反应器的运行提供理论指导。得到的主要结论如下:(1)甲烷氧化菌在气液界面附近向甲烷和氧气浓度较高处运动并富集,甲烷和氧气的气体体积混合比为1:1、菌体浓度越高、气泡初始体积越小时,越有利于气泡内部气体的传输和降解。(2)气泡涌入使气泡界面发生震荡,强化气液界面处的传质效果;气体流量对气泡的分离体积和等效直径没有影响。(3)聚并后,由于气泡体系内总的表面积减少,表面能转变成机械能,气泡开始发生剧烈的震荡。受限空间内,气泡聚并后,主气泡与前后侧壁面相接触,当主气泡界面上的震荡波与壁面接触时,能量损失较大。(4)气体的流量和液体流量对微通道内气泡的流型具有重要影响,并对甲烷氧化菌降解甲烷气体产生影响。
[Abstract]:In the process of coal mining, methane gas which exists in coal body or surrounding rock in free or attached state will be diluted and emptied to ensure safe production.However, this will not only cause a waste of energy, but will also exacerbate Greenhouse Effect.Methane is the second largest greenhouse gas after carbon dioxide, but its potential to contribute to global warming is 25 to 30 times greater than carbon dioxide.In recent years, with the rapid development of biological engineering and environmental engineering, the application of biochemical transformation technology in coal mine gas control has become a very prospective and challenging emerging research field.Based on methane contained in methane oxidizing bacteria biodegradable gas, the bubble dynamics characteristics of methane oxidizing bacteria suspension in a multi-scale biochemical reactor were systematically studied in this paper.And the transport characteristics of methane and oxygen mixture in multiscale biochemical reactor.In this paper, by changing the parameters of gas flow rate, bacterial liquid concentration, capillary diameter, orientation, center distance, and so on, we studied the bubble growth, separation and influx in biochemical reactor at different scales by using visual experimental method, and by changing the parameters, such as gas flow rate, bacterial liquid concentration, capillary diameter, orientation, center distance and so on.Dynamic behavior in processes such as coalescence and ascending motion.The experimental results provide theoretical guidance for the design of gas dispensers and the operation of biochemical reactors at different scales.Due to the reduction of the total surface area and the conversion of surface energy into mechanical energy, the bubble began to vibrate violently.In the confined space, the main bubble is in contact with the front and rear sidewall after the bubble is coalesced. When the shock wave on the main bubble interface is in contact with the wall, the energy loss is larger. 4) the flow rate of the gas and the flow rate of the liquid have an important influence on the flow pattern of the bubble in the microchannel.The degradation of methane gas by methane-oxidizing bacteria was also affected.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD712

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