Effect of fine solid particles on absorption rate of gaseous CO

Abstract

The influence of the properties of solid particles in slurry on the absorption of CO₂ in the slurry was investigated in a stirred thermostatic reactor. The absorption experiments were carried out in three different slurries consisting of water, cyclohexane and soybean oil, respectively, and three kinds of solid particles (active carbon, active alumina and silica gel) were incorporated into each of the above mentioned slurries separately. The experimental results show that the active carbon particles could enhance the absorption rate of gaseous CO₂ in the aqueous slurry, while in the cyclohexane slurry, active carbon particles indicated no the absorption enhancement effect. However, it was observed that the active alumina and silica gel particles could enhance the absorption rate of CO₂ in the cyclohexane slurry. These phenomena indicate that the solid particles, which could enhance the gaseous CO₂ absorption rate, should possess two properties simultaneously, i.e. they rejected the solvent and had higher adsorption capacity for the solute. The experimental results also show that, as for those solid particles which could enhance the gas absorption rate, the enhancement increased quickly with the increase of solid concentration in slurry at first, and then reached a constant value gradually. It was also found that the enhancement factor was related to the coverage fraction of solid particles on the gas-liquid interface, and due to the reduction of surface fraction with increasing stirred speed, the enhancement factor decreased.

Keywords

absorption enhancement / enhancement factors / surface coverage fraction / adsorption capacity