Gas solubility maxima in mixtures of physical absorbents and chemisorbents

Experimental data demonstrate that mixing of absorbents gives the possibility to increase gas solubility. This effect may be predicted using a simplified theory of solution. Solution theory predicts that increasing solubility is possible in mixtures with positive deviations from Raul's law and when some other conditions exist. This effect is greatest near lamination of solvent mixture. Gas solubility in regular solution may increase not more than 1.6 times. A similar effect may arise when mixing chemisorbents. This effect is very large. When an equal saturation degree of solution by gas is fixed, the equilibrium pressure of gas above solution may decrease by 10–50 times as compared with the pressure above the solution of one of the chemisorbents. Theory and experiment demonstrate that the positive effect is greatest when the saturation degree is small, and this effect becomes negative when the saturation degree is great. These results give a new explanation for the effect of chemisorbent mixing in industrial processes such as the Benfield process.