第二液相的加入对气液传质系数的影响

Effect of second liquid phase on gas-liquid mass transfer coefficient

以搅拌罐中的水吸收CO2为研究体系,分别采用异戊醇、苯和正己烷为第2液相,通过实验考察了第2液相的加入对气液传质的影响。实验结果表明:第2液相的加入对气液体积传质系数KLa有很大的影响,且不同的第2液相的影响程度也不同。在一定的操作条件下,KLa均随搅拌速度和第2液相体积分数的增加呈先增大后减小的趋势,随表观气速(在一定范围内)的增加而增加。KLa值可通过插值函数微商法直接测得,也可通过渗透模型计算得到。直接测得的KLa值与渗透模型计算得到的KLa值的结果吻合良好。说明了渗透模型中的计算过程适合此气液传质系统,模型中的气泡直径及气液接触面积的计算数据可为气液传质过程的研究提供基础数据。

The experiment was carried out in a stirred tank reactor,choosing CO2 as the gas solute,H2O as continuous phase,isoamyl alcohol,benzene and n-hexane as the second liquid phase respectively.The effects of the second liquid phase on gas-liquid mass transfer were studied in the experiment.The experimental results show that the addition of the second liquid phase has a great influence on gas-liquid volumetric mass transfer coefficient（KLa）.And the enhancement degree of different second liquid phase is different.Under certain operating conditions,KLa increases firstly,and then decreases as the stirring rate and volume fraction of the second liquid phase increase,and KLa increases as the superficial gas velocity increases in a certain range.KLa can be obtained by interpolation function of derivative method or calculated through the penetration model.The theoretical value of KLa calculated by the model is mainly consistent with the experimental values.It shows that the calculated method of penetration model is applicable to this gas-liquid mass transfer system.The calculated data of bubble diameters and gas-liquid interfacial area in the model can provide fundamental data for the gas-liquid mass transfer process.