旋流气液两相强化吸收CO_2的传质性能

Mass transfer performance of enhanced CO_2 absorption in swirling flow field

为强化二氧化碳的吸收过程,采用一类旋流逆向气液多级接触的方式,以Na OH溶液为吸收剂,研究其与大跨度浓度CO2(2.5%~15%)接触反应的传质性能。分别探讨了吸收剂浓度、吸收剂流量、烟气CO2浓度、烟气流量及反应温度对气相总体积传质系数(Kga)的定量影响。结果表明,在实验条件下,其Kga可达(4.53×10-5)^(9.22×10-5)kmol·m-3·s-1·k Pa-1。与双级直流喷雾和单级旋流喷雾相比,旋流逆向气液多级接触能够有效强化大跨度浓度CO2的吸收过程。Kga随吸收剂浓度、流量和反应温度的增加而增加,随CO2浓度增加呈现先增加后减小(CO2浓度大于5%)的非线性关系,随气体流量增加先增加后趋于稳定。

To intensify the CO2 absorption process, a reactor based on swirling and multi-staged liquid-gas contact was used to examine the mass transfer performance of long-concentration span CO2 （2.5%—15%） capture with NaOH solution. The effects of absorbent concentration, absorbent flow rate, CO2 concentration, gas flow rate and reaction temperature on volumetric overall mass transfer coefficient （Kga） were experimentally investigated. The mass transfer coefficient varied from 4.53×10^-5 to 9.22×10^-5 kmol·m^-3·s^-1·kPa^-1 under the experimental conditions. Compared with axial spray with double stages and swirling spray with single stage, swirling-based multi-staged spray reactor was able to effectively enhance the performance of absorption of long-concentration span CO2. A high concentration and a high flow rate of the absorbent, and a high reaction temperature helped to increase Kga. Kga increased with the increase of CO2 concentration, but decreased while CO2 concentration was more than 5%. Kga increased and then stabilized with increase of gas flow rate.