Abstract:

The intensification and mechanism of gas-liquid mass transfer in a water-sparged aerocyclone by microparticles were conducted in this paper. The effects of solid concentration c_s, gas inlet velocity u_g and liquid jet velocity u_L on specific mass transfer area a, mass transfer coefficient of liquid side k_L, volumetric mass transfer coefficient k_La and mass transfer intensification factor E were investigated by using a chemical method (CO₂-air-NaOH absorption system) and a physical method (CO₂-air-H₂O absorption system). The results indicated that the k_L, a, k_La and E increased and then decreased with the increase of solid concentration c_s, c_s has a maximum value. Solid particles could intensify mass transfer, increasing k_L, a and k_La under different u_g and u_L, whereas E decreased with the increase of u_g and u_L. The mechanism of solid particles intensifying gas-liquid mass transfer was realized through the three paths from increasing a, k_L and S, but the increase of the surface renew frequency S was the major mechanism.

Key words: water-sparged aerocyclone, solid particle, gas-liquid mass transfer intensification

摘要：

在一种新型高效的气液传质设备——水力喷射-空气旋流器(WSA)中,研究了第三相固体粒子对气液传质的影响。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)测定了不同固含率c_s、进口气速u_g、液体喷射速度u_L下的有效相界面积a和液膜传质系数k_L,并由此得到总体积传质系数k_La和增强因子E。结果表明,随着粒子固含率增大,k_L、a、k_La和E先增大后减小,存在一适宜固含率。在不同进口气速和液体喷射速度下,加入微粒后,k_L、a、k_La均增大,但E随进口气速和液体喷射速度增加而减小。微粒加入后,主要从a、k_L和表面更新频率S这3方面强化了气液传质,但主要是通过增强表面更新频率S而实现的。

关键词: 水力喷射-空气旋流器, 微粒, 气液传质强化