Development of slurry bubble column with lithium silicate to recover hot CO₂ gas from flue gas

To reduce the release of greenhouse gas from massive emission sources into atmosphere, a slurry bubble column suspending lithium silicate is proposed to remove hot CO₂ from flue gas or pre-combustion effluent gas. As the liquid phase, the molten salt consisting of binary carbonates was used. The slurry suspending solid particles of lithium silicate in the molten salt promoted to mix gas and slurry in the column so that the absorption rate of CO₂ was improved. In this study, the effects of some important operating conditions such as superflcial flue gas velocity, the concentration of lithium silicate powder in the slurry and the height of the slurry on CO₂ absorption were investigated to optimize the system. The CO₂ absorption increased with increasing superflcial gas velocity and decreasing slurry concentration. Fractional CO₂ recovery increased with increasing the height of the slurry. The apparent rate constant and the apparent activation energy were determined in the reaction system. Moreover, an endurance test was conducted to confirm stable recovery capacity, in which the proposed CO₂ recovering system performance was repeatedly maintained.