Intensifying the Absorption of CO 2 in Water Using a Static Mixer. Part I: Effect of Measurement Technique

This study investigates the use of a novel static mixer to intensify the physical absorption of CO 2 in water. To assess the efficiency of this tubular reactor, the temporal variation of absorbed CO 2 was tracked along the reactor using three methods, namely, inline pH measurements, direct CO 2 measurements using a CO 2 analyzer, and titration. The effect of varying the liquid and gas flow rates on the mass transfer performance was investigated and analyzed. This article focuses on a comparison between the three methods of measurements to highlight differences in their results and sources of error. The findings demonstrated the reliability of the titration technique in quantifying dissolved CO 2 concentrations when compared to the other two methods. In addition, it was found that the measured volumetric mass transfer coefficients, k L a, for this reactor were several orders of magnitude larger than those reported using conventional reactors such as mechanically agitated tanks and bubble columns. The values of k L a reached a maximum of 0.83 s –1 at low specific energy consumption rates (≈0.016 kWh/t) within 0.35 s of residence time in the reactor/contactor.