固体颗粒对搅拌罐中气液传质的影响

摘要

在带有Rushton搅拌桨的搅拌罐中，研究了恒定温度和恒定气体流量条件下不同粒径的固体颗粒和搅拌速率对气液传质速率的影响．结果表明：固体体积分数小于0.08%,时，石英砂(41.1,µm和640,µm)对气液体积传质系数kLa没有影响；而对于碳酸钙颗粒(5.07,µm)，当其体积分数大于0.4%,时，kLa 随着固体含量的增加而增大．通过对实验数据的拟合，得到一个含有功率输入、浆液有效黏度、颗粒粒径和固含量的半经验公式，该公式能够很好地表达颗粒对气液传质的影响．%Gas-liquid mass transfer in a stirred tank was studied with a Rushton impeller. Mass transfer rate was investigated using various concentration of different-sized solid particles,as well as different rotation speed at a constant temperature and gas flow rate. When the solid volume fraction was less than 0.08%,no effect of quartz sands(41.1,µm and 640,µm)on the volumetric mass transfer kLa was observed. However,kLa was increased when the solid volume fraction of calcium carbonate particles(5.07,µm)was above 0.4%,. A semi-empirical equation of specific power input,effective viscosity of slurry,particle size,and solid loading was obtained by fitting the experimental data. This equation can successfully describe the effect of particles on gas-liquid mass transfer.