多级错流旋转填料床的气相压降特性研究

发布时间：2018-05-12 16:48

本文选题：多级错流旋转填料床 + 气相压降　；参考：《中北大学》2015年硕士论文

【摘要】：错流旋转填料床在气体吸收、吹脱、除尘等单元过程的工业应用表明，具有气体处理能力大、压降低、液相传质系数高、设备体积小、投资省等优点，而被誉为化学工业中的“晶体管”。但现有结构的错流旋转填料床对强化气相传质效果不明显，而不适用于气-液膜，特别是气膜控制的传质过程。因此，本实验室开发了一种多级错流旋转填料床，将原来的单层填料设计成三层填料，即上、下两层旋转，中间层静止，起到强烈扰动气流，从而达到强化气相传质的作用。旋转填料床的气相压降直接关系到气体的输送能耗大小和工业应用。目前，关于旋转填料床的气相压降模型及实验结果不具备通用性，特别是对本实验室开发的新型旋转填料床。因而，本文对其结构、填料类型和操作参数对气相压降的影响规律进行了研究，以期优化结构、筛选填料，并为工业化设计提供参考。本文主要选用了塑料鲍尔环和不锈钢波纹丝两种填料，以空气-水为体系，分别考察了空床气速、超重力因子及液体喷淋密度等操作参数和结构对气相压降的影响规律，结果表明：塑料鲍尔环下的湿床总压降随超重力因子和液体喷淋密度的增大呈先减小后增大的趋势，而上、下两层填料的湿床压降随超重力因子的增加呈先减小后不变的趋势，液体喷淋密度增加时，，总湿床压降和各层湿床压降均增大；不锈钢波纹丝填料下的湿床总压降随超重力因子的增加呈升高规律，上、下两层填料的湿床压降随超重力因子和液体喷淋密度的增加而增大，说明湿床压降变化规律受到填料特性的明显影响；而两种填料下，总干床压降和各层干床压降均随空床气速、超重力因子的增大而升高，塑料鲍尔环的干、湿压降高于不锈钢波纹丝网的；中间层填料的湿床压降均随超重力因子和液体喷淋密度的增大而升高，从侧面反映出超重力因子的增大和液体的引入会增加气体的周向速率。在上、下两层填料均为塑料鲍尔环时，将中间层填料依次变为：塑料鲍尔环、不锈钢波纹丝和除去填料,对比三种情况下的各床层气相压降变化,研究表明：操作条件相同的情况下,随着中间层填料的变换,下层填料干、湿床压降基本不变,中间层填料干、湿床压降减小,上层填料干床压降增大,湿床压降基本不变,说明中间层填料能起到消除气旋的作用,且装填的填料形体阻力越大效果越好。通过理论分析和合理简化,将多级错流旋转填料床气相压降分为：气体进口、出口阻力压降、以及气体流经上、中、下三层填料床层产生的压降,经推导得出多级错流旋转填料床的气相总压降模型为：用塑料鲍尔环填料下的气相压降数据拟合模型系数,得到模型计算结果的误差范围在20%以内,说明模型能够较好地反映实验结果以及预测气相压降的大小,可用来指导多级错流旋转填料床改进和工业化应用。
[Abstract]:The industrial application of cross-flow rotating packed bed in unit processes such as gas absorption, blowing off and dust removal shows that it has the advantages of large gas treatment capacity, low pressure, high mass transfer coefficient of liquid phase, small equipment volume and low investment. And known as the chemical industry in the "transistor". However, the cross-flow rotating packed bed with existing structure has no obvious effect on the enhancement of gas phase mass transfer, but not suitable for the gas-liquid film, especially for the gas-film controlled mass transfer process. Therefore, a multi-stage cross-flow rotating packed bed has been developed in our laboratory. The original single-layer packing is designed as three layers of packing, that is, the upper and lower layers rotate, and the intermediate layer is still, which plays a strong disturbance to the gas flow, thus enhancing the mass transfer in the gas phase. The gas pressure drop of rotating packed bed is directly related to the energy consumption of gas transportation and industrial application. At present, the gas phase pressure drop model and experimental results of rotating packed bed are not universal, especially for the new rotating packed bed developed by our laboratory. Therefore, the effects of structure, packing type and operating parameters on gas pressure drop are studied in this paper, in order to optimize the structure, screen the packing and provide reference for industrial design. In this paper, two kinds of fillers, plastic Bauer ring and stainless steel corrugated wire, were used to investigate the influence of air velocity, hypergravity factor and liquid spray density on gas phase pressure drop in air-water system. The results show that the total wet bed pressure drop under the plastic Bauer ring decreases first and then increases with the increase of the hypergravity factor and the liquid spray density, while the wet bed pressure drop of the next two layers of fillers decreases first and then remains the same with the increase of the hypergravity factor. With the increase of liquid spray density, the total wet bed pressure drop and the wet bed pressure drop in each layer increase, and the total wet bed pressure drop under stainless steel corrugated wire filler increases with the increase of hypergravity factor. The wet bed pressure drop of the next two fillers increases with the increase of the hypergravity factor and the liquid spray density, which indicates that the variation of the wet bed pressure drop is obviously affected by the packing characteristics. The total dry bed pressure drop and each layer dry bed pressure drop increase with the increase of empty bed gas velocity and hypergravity factor. The dry and wet pressure drop of plastic Bauer ring is higher than that of stainless steel corrugated wire mesh. The wet bed pressure drop of the intermediate packing increases with the increase of the hypergravity factor and the spray density of the liquid. It can be seen from the side that the increase of the hypergravity factor and the introduction of the liquid will increase the circumferential rate of the gas. When the upper and lower layers of packing are all plastic Bauer rings, the intermediate packing will be changed into plastic Bauer ring, stainless steel corrugated wire and removal filler, and the pressure drop of each bed will be compared under three conditions. The results show that under the same operating conditions, with the change of the intermediate packing, the wet bed pressure drop is basically unchanged with the lower packing dry, the middle layer packing is dry, the wet bed pressure drop decreases, the upper packing dry bed pressure drop increases, and the wet bed pressure drop basically does not change. The results show that the interlayer packing can eliminate the cyclone, and the bigger the packing body resistance is, the better the effect is. Through theoretical analysis and reasonable simplification, the gas pressure drop of multi-stage cross-flow rotating packed bed is divided into three parts: gas inlet, outlet resistance pressure drop, and pressure drop caused by gas flowing through the upper, middle and lower layers of packed bed. The gas phase total pressure drop model of multi-stage cross-flow rotating packed bed is derived as follows: The model coefficient is fitted with the gas phase pressure drop data under the plastic Bauer ring packing, and the error range of the model calculation results is less than 20%, which shows that the model can reflect the experimental results and predict the gas pressure drop well. It can be used to guide the improvement and industrial application of multi-stage cross-flow rotating packed bed.
【学位授予单位】：中北大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ051.1

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