Abstract: Water-sparged aerocyclone(WSA)is a new type of gas-liquid mass transfer equipment with high efficiency,the mass transfer mechanism in WSA was investigated in this paper.The interfacial area(a)was determined by the chemical reaction method with CO₂-NaOH solution system,and the liquid mass transfer coefficient(k_L)was measured by the physical absorption method with CO₂-H₂O system.The a,k_L and k_La increase with gas inlet velocity(u_g)and liquid jet velocity(u_L)because of the gas-liquid intense interaction in WSA.The empirical formulae were developed for a,k_L and k_La,i.e, a=0.0024Re_g^1.25We_L^0.079,Sh_L=35.31Re_g^0.2303We_L^0.13,k_La=6.52×10^-8Re_g^1.48We_L^0.21,which fit the experimental data well and could be well used to predict the mass transfer characteristics in WSA.The mass transfer models of Whitman' double film theory,Higbie' penetration theory and Danckwerts' surface renewal theory can be well used to interpret the mass transfer mechanism of gas-liquid jet-aerocyclone system in WSA,and the surface renewal theory is the primary mass transfer mechanism.

Key words: water-sparged aerocyclone, gas-liquid mass transfer, interfacial area, chemical absorption

摘要： 对一种新型高效的气液传质设备——水力喷射-空气旋流器(WSA)的传质机理进行了研究。分别采用化学吸收法(CO₂-空气-NaOH体系)和物理吸收法(CO₂-空气-H₂O体系)测定了不同进口气速、不同液体喷射速度下的有效相界面积a和液膜传质系数k_L,并由此得到体积传质系数k_La。结果表明,由于WSA中气液间的强交互作用,a、k_L以及k_La均随进口气速和液体喷射速度增大而增大。采用量纲分析法对实验数据进行了归纳,拟合出了a、k_L和k_La随气相Reynolds数Re_g、液相Weber数We_L之间的经验公式:a=0.0024Re_g^1.25We_L^0.079,Sh_L=35.31Re_g^0.2303We_L^0.13,k_La=6.52×10^-8Re_g^1.48We_L^0.21,这些关联式能较好地预测WSA的传质性能。研究还表明,在WSA中的气液射-旋流传质体系中,传质过程符合双膜理论、表面更新理论和溶质渗透理论,但以表面更新机理为主。

关键词: 水力喷射-空气旋流器, 气-液传质, 比相界面积, 化学吸收法