Numerical simulation on gas-liquid flow, heat, and mass transfer characteristics in a dual-contact-flow absorption tower

Because of the limitation of accurate measurement of microscopic parameters in the dual-contact-flow absorption tower, the diameter, velocity, temperature of a single droplet, and the concentration of matter in it are difficult to be obtained through experimental methods. However, these data are of crucial importance to understand the behaviors of liquid phase in the absorber. In this paper, the microscopic motion, heat, and mass transfer characteristics of droplets in the dual-contact-flow absorption tower have been numerically simulated, and the results have been validated by experimental data. The motion trails of droplets under different initial jetting velocities and gas velocities are studied, and the fall-back characteristics have been obtained. The critical diameters of droplets increase remarkably with the increase of gas velocity but have limited relationship with the liquid initial jetting velocity. The heat and mass transfer capacities of droplets have also been investigated. It is found that because of the diversity between the concentration relaxation time and the temperature relaxation time, there may be considerable difference between heat and mass transfer behaviors. All the work above is a complement of the basic performance of droplets in the dual-contact-flow absorber and can supply guidance for estimating the practical application performance.