Canadian Journal of Chemical Engineering, Vol.93, No.9, 1556-1566, 2015
Numerical Study of Gas-Liquid Flow in Dual-Contact-Flow Absorber with One-Dimensional Two-Way Coupled Model
The dual-contact-flow absorber is widely used in gas-liquid reactions, such as wet flue gas desulfurization process. Yet the exemplification of the micro-mechanisms of the flow, heat, and mass transfer of a liquid droplet swarm in the absorber is still lacking. Based on the industrial principles of high efficiency and practicability, a one-dimensional two-way coupled model is established in this paper, in order to study the micro-mechanisms of gas-liquid flow in a dual-contact-flow absorber. By incorporating the discrete phase, the liquid density distribution, as well as the heat and mass transfer of the liquid particle swarm, are obtained under different liquid initial jetting velocities and empty cross-sectional gas velocities. In addition, the simulation results have been verified by parallel experiment data. The results indicate that the height of the liquid bed is mainly decided by the liquid initial jetting velocities. It has also been found that the top of the liquid bed where the highest heat transfer appears will hold the greatest number of liquid droplets; thus it is essential to choose a proper initial jetting velocity in applications. The most intense mass transfer area, unlike the heat transfer in this manuscript, is at the bottom of the absorber where the liquid is injected from the nozzles. The empty cross-sectional gas velocity determines what size of liquid droplets will be carried away by the gaseous phase from the top of the absorber. The study may provide useful guidelines for dual-contact-flow absorber design and applications.