279221 CO2 Separation Using Mg(OH)2 Solutions – Dissolution Kinetics and Vapor-Liquid-Solid Equilibrium Studies of CO2- Mg(OH)2 System
Coal-fired power plants are responsible for a considerable amount of total anthropogenic CO2 emissions throughout the world. CO2 from flue gases can be absorbed by Mg(OH)2 slurry at 52 °C in a column followed by a regeneration step in a stripper operated at 65 °C.
One of the most important steps in the CO2 scrubbing process is the rate at which magnesium hydroxide dissolves from the solid part of the slurry and becomes available for reaction with absorbed CO2. The dissolution rate kinetics of Mg(OH)2 was studied using a pH stat and the dissolution rate was determined based on acid consumption required to maintain a preset pH value. The effects of pH, temperature, mixing and particle size on the dissolution rates of Mg(OH)2 will be presented. A dissolution rate kinetic expression obtained under different operating conditions will also be presented.
Knowledge of Vapor liquid solid equilibrium (VLSE) of CO2 in Mg(OH)2 is essential for the proper design and operation of absorption and desorption equipment. The VLSE data for the Mg(OH)2 – CO2 system under various operating conditions of pressure, temperature, and concentration of Mg(OH)2 will be presented. A suitable model for fitting the VLSE data will also presented.