基于微液滴分散强化吸收传质的天然气脱水机理与特性研究

Conventional TEG absorption equipment has the problem of excessive volume and weight, and it is a development trend of natural gas TEG dehydration technology to develop the inline absorption equipment. Although co-current flow between micro-droplets and strongly turbulent gas flows in pipe could intensify the absorption and mass transfer process in equipment, the flowing mass transfer mechanism and characteristics are still not very clear up to now. The aim of this project is to study experimentally and theoretically the scientific problems, dispersive mixing of micro-droplets and transient mass transfer, involved in the process of absorption mass transfer intensification depending on turbulent co-current between micro-droplets and gas flows in pipe. At the micro-scale, by means of theoretical analysis, online measuring of movement and diameter of droplets, the momentum relaxation between high-speed gas flows and micro-droplets can be studied, thus the mechanism of dispersing and mixing between micro-droplets and high-speed gas flows can be clarified. Afterwards, it will be revealed what the mechanisms of rapid transfer mass between micro-droplets and high-speed gas flows are, through analyzing the effect law of the degree of gas-liquid mixing and relaxation time scale on the mass transfer rate of micro-droplets ,with the combination of online measuring on gas humidity. At the macro-scale, the theoretical derivation and experimental research will be conducted to establish the theoretical calculating theory of mass transfer characteristics and dehydration efficiency in the pipe sections used for mixing, absorption and mass transfer. The research results of this project could not only provide fundamental theory and technical supports for independent research and development of compact, efficient, inline, contacting mass transfer and absorption equipments used for gas dehydration，but also can be extended directly to some applications such as gas purification in energy saving and environment protection areas.

传统三甘醇吸收设备存在体积和重量过大的问题，吸收设备管道化是天然气三甘醇脱水技术的发展趋势。微液滴与强湍流气体管内同向流动可强化设备的吸收传质过程，但其流动传质机制和特性尚不明了。本项目拟围绕管道内微液滴气液同向湍流强化吸收传质过程中涉及的微液滴分散混合和瞬态传质问题开展实验和理论研究。从微观层面上，通过理论分析和液滴运动行为、粒径在线观测等手段，分析高速气流与微液滴之间的动量驰豫作用，阐明微液滴在高速气流中的分散混合机制。在此基础上结合气体湿度在线测量手段，分析气液混合均匀度和驰豫时间对微液滴传质速率的影响规律，揭示微液滴与高速气流之间的瞬态传质机制。从宏观层面上，通过理论推导和实验研究，建立混合传质吸收管段传质特性和脱水效率的理论计算模型。研究成果可为天然气脱水用紧凑高效管式接触吸收设备的自主研发提供理论指导和基础数据支撑，还可直接应用到节能环保领域的气体净化处理等场合。

甘醇法脱水是天然气集输处理领域常用的露点控制方法，海洋和陆上边远区块气田目前都迫切需要高效紧凑的甘醇脱水吸收技术以降本增效。将三甘醇雾化成微小液滴，同时提高气液两相流动的湍流程度，进而强化气液传质过程，是实现天然气三甘醇脱水吸收设备高效化和紧凑化的有效途径。目前管内复杂流道内液体射流破碎雾化机理、微液滴分散混合机制、微液滴吸收传质特性尚不明确，阻碍高效管式气液接触吸收脱水设备的开发及应用。本项目基于高速图像测试和数值模拟分析，研究了液体射流在方管等截面和变截面流道结构内液体射流破碎形态和机理，阐明了微液滴在高速气流的分散混合机理，得到了流道结构对管式气液雾化混合设备内高速气流和微液滴分散的影响规律。建立了管式气液接触吸收器的设计准则，掌握了结构参数、操作参数对圆管结构雾化混合器内气液流动和混合特性影响规律。得到了三甘醇浓度、液气比、吸收段长度、气体流量等参数对管式气液接触吸收器吸收管段传质效能的影响规律，掌握了液滴粒径和雾化效率与脱水效果的关系，确定了三甘醇微液滴吸收脱水传质的时间尺度。研究结果可为天然气脱水用紧凑高效管式接触吸收设备的自主研发提供基础理论和技术支持，也可直接移植应用到煤层气、页岩气、天然气水合物(可燃冰)等的脱水处理。另外，在节能环保领域的VOCs处理、工业废气处理、CO2捕集工艺中，本项目的研究成果可为相关研究人员提供指导和借鉴。