错流旋转填料床传质特性影响因素的实验研究

Experimental Study on Influential Factors of Mass Transfer in a Cross-flow Rotating Packed Bed

采用CO_2-Na OH体系,在中试规模的实验装置上进行传质实验,考察了气速、液体喷淋密度、超重力因子、气液接触时间对错流旋转填料床的总体积传质系数KLa及有效传质比表面积a_e的影响.结果表明,K_La和a_e均随气速、液体喷淋密度和超重力因子增加而增大,K_La随气液接触时间增加先缓慢增大后急剧下降,a_e则随气液接触时间增加而缓慢下降.最佳操作条件为:气速1.69 m/s,液体喷淋密度32 m^3/(m^2×h),超重力因子104,气液接触时间0.1 s.错流旋转填料床在处理大气量气体时传质效果增强,是同类文献错报道的1.52~2.32倍.对各操作参数下所得实验数据进行回归,得关联式K_La=1.8221(atD_L/d_p)Re_L^(0.6371)GrL^(0.0548)Sc_L0.0623和a_e/a_t=2980.9Re_L^(0.2349)Fr_L^(-0.045)WeL0.5023f^(-0.5).

A pilot-scale experimental apparatus was used the mass transfer in a cross-flow rotating packed bed, total volumetric mass-transfer coefficient KLa, effective interfacial area ae were measured by considering the effects of gas velocity, liquid spray density, high gravity factor and gas-liquid contact time with a system of CO2 chemisorption into Na OH solution. The results show that both volumetric mass transfer coefficient and effective interfacial area increase with increasing of gas velocity, liquid spray density and high gravity factor, KLa increases slowly at first and declines sharply with increasing of gas-liquid contact time, while ae decreases slowly with increasing of gas-liquid contact time. The optimal operation conditions are gas velocity 1.69 m/s, liquid spray density 32 m^3/（m^2·h）, high gravity factor 104, and gas-liquid contact time 0.1 s. The mass transfer performance in the present cross-flow rotating packed bed can be enhanced up to 1.52~2.32 times than that reported in the literature under a large gas flow rate. Empirical equations of KLa and aecan be expressed as KLa=1.8221（atDL/dp）ReL^（0.6371）GrL^（0.0548）ScL0.0623 and ae/at=2980.9ReL^（0.2349）FrL^（-0.045）WeL0.5023f^（-0.5）.