LAUSR

Abstract The reaction kinetics of carbon dioxide and sodium hydroxide (nominally 0.1 N and 0.3 N) in aqueous glycerol were measured in a wetted wall column (WWC) at 20, 30, and 40 °C. Glycerol was added at 0–89 wt% to achieve a liquid viscosity ( μ L ) of 0.89–65 cP. Compared to pure aqueous alkaline solution, the absorption rate ( k g ′) initially increased by 30% and then decreased rapidly by 75% with increasing glycerol. Based on the measured k g ′, a model was developed to calculate the overall reaction rate constant ( k Alk ), which resulted from the competing effects of CO 2 /NaOH ( k OH - ) and CO 2 /glyceroxide ( k Glycerol - ) reactions. The k Glycerol - was 6–7 times faster than k OH - . The non-monotonic trend of k g ′ was the combined effect of k Alk increasing and diffusivity ( D CO2 ) decreasing when glycerol increased. The effect of alkalinity depletion at the gas/liquid interface has been included in the kinetic model. The average depletion for 0.1 N NaOH is 4% for water and 20% for 89 wt% glycerol. Average depletion was less than 3% for 0.3 N NaOH. The addition of 0.05 N sodium carbonate has an insignificant effect on k g ′.