Intensifying the Absorption of CO2 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 CO2 in water. To assess the efficiency of this tubular reactor, the temporal variation of absorbed CO2 was tracked along the reactor using three methods, namely, inline pH measurements, direct CO2 measurements using a CO2 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 CO2 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(approximate to 0.016 kWh/t) within 0.35 s of residence time in the reactor/contactor.