旋转填充床空腔内传质的研究

发布时间：2018-06-28 02:43

本文选题：旋转床 + 液膜控制　；参考：《北京化工大学》2015年硕士论文

【摘要】：本文以卧式旋转填充床作为实验设备,分别考察了液膜控制体系与气膜控制体系下,空腔区与整床的传质情况,空腔区占整床的传质比例,转速液量和温度等变量对实验结果的影响。对于NaOH吸收CO2体系,随着转速的增加,整床的CO2脱除率先迅速增加,又有所降低；空腔区的CO2脱除率随着转速的增加而增大。随着液体流量的增加,空腔区和整床的CO2脱除率均有所提高。温度对于整床和空腔区的CO2脱除率影响不大。空腔区占整床的传质比例为23%-29%。对于MDEA吸收CO2体系,空腔区占整床传质比例为29%-33%。即对于液膜控制体系,空腔区所占传质比例约为整床的1/4,传质的主要部分发生在填料区。对于水吸收NH3体系,实验测得空腔区占整床的传质比例大约为82%,这一比例随转速、气相流量、液相流量和温度的变化而基本不变。即空腔区占到整床传质的大部分比例,这证明了气相端效应区(外端效应区)的存在,以及其对气膜控制体系传质的巨大贡献。将液相为氨水时空腔区的NH。吸收率与液相为清水时整床的NH。吸收率进行对比,消除了液相浓度梯度对实验结果的影响,空腔区的传质仍然占到整床传质的大部分比例。对于水吸收NH3体系,空腔区的气相体积总传质系数KGa要大于整床的气相体积总传质系数KGa,空腔与整床的气相体积总传质系数KGa随着气量的增大而大幅增加。液相流量的增大使空腔区与整床的NH。吸收速率均增加,相应气相体积总传质系数KGa也增加。温度的升高使空腔与整床的NH。吸收率和气相体积总传质系数KGa均降低。
[Abstract]:In this paper, the mass transfer between the cavity area and the whole bed in the liquid film control system and the gas film control system is investigated with the horizontal rotating packed bed as the experimental equipment, and the mass transfer ratio of the cavity area to the whole bed is investigated. The effect of the speed of liquid and temperature on the experimental results. For NaOH CO2 absorption system, with the increase of rotating speed, the CO2 removal rate of the whole bed increases rapidly and then decreases, and the removal rate of CO2 in the cavity increases with the increase of rotational speed. With the increase of liquid flow rate, the removal rate of CO _ 2 in the cavity and in the whole bed increased. The temperature has little effect on the removal rate of CO2 in the whole bed and cavity. The mass transfer ratio of the cavity area to the whole bed was 23-29. For MDEA CO2 absorption system, the mass transfer ratio between the cavity area and the whole bed is 29- 33. For the liquid membrane control system, the proportion of mass transfer in the cavity is about 1 / 4 of that in the whole bed, and the main part of the mass transfer occurs in the packing area. For the system of water absorption of NH _ 3, the mass transfer ratio of the cavity area to the whole bed is about 82%, which is basically unchanged with the changes of rotational speed, gas flow rate, liquid flow rate and temperature. That is, the cavity area accounts for most of the mass transfer in the whole bed, which proves the existence of the gas phase end effect region (the outer end effect region) and its great contribution to the mass transfer of the film control system. The liquid phase was transformed into NH in the spatiotemporal cavity region of ammonia water. When the absorptivity and liquid phase are pure water, the NH of the whole bed is obtained. The absorption rate was compared and the effect of liquid concentration gradient on the experimental results was eliminated. The mass transfer in the cavity still accounted for most of the mass transfer in the whole bed. For NH _ 3 absorption system, the gas phase mass transfer coefficient KGa in the cavity region is larger than that in the whole bed, and the gas phase volume mass transfer coefficient KGa between the cavity and the whole bed increases greatly with the increase of gas volume. The increase of liquid flow rate makes the cavity area and the whole bed NH. The absorption rate increases and the mass transfer coefficient KGa increases. The increase of temperature makes the cavity and the whole bed NH. Both the absorptivity and the mass transfer coefficient KGa decreased.
【学位授予单位】：北京化工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ021.4

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