Comparative Evaluation of the Contact Elements Efficiency for Barium Sulfide Solution Carbonization

The article presents the results of an experimental study aimed at obtaining scientifically valid data on the kinetics of absorption of carbon dioxide by a barium sulfide solution and the effect of the design of contact elements (trays) on the mass transfer coefficient in this process. The work was carried out using a laboratory model of the absorber, in which it was possible to install trays of various types. Analysis of literature sources showed that the process of a BaS solution carbonization takes place in two stages, sharply differing in pH. An experimental study of CO₂ absorption kinetics under the conditions of the first stage of the process made it possible to identify the most significant factors influencing its rate. It was also found that the limiting stage of mass transfer is the resistance in the gas phase. The carbonization rate at the second stage is significantly lower than at the first stage and is controlled by the kinetics of the chemical reaction of CO₂ hydration. Mathematical processing of the results of testing models of the cap, sieve, and double-flow trays made it possible to obtain formulas for calculating the mass transfer coefficients for each of them. In the studied range of gas velocities, the mass transfer coefficient on a dual-flow tray was 1.5–2 times lower than on a sieve tray and 2–2.5 times lower than on a cap tray. The data obtained were used in the design of the absorption apparatus.