Intensifying the Absorption of CO₂ in Water Using a Static Mixer. Part I: Effect of Measurement Technique

Abstract

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 (≈0.016 kWh/t) within 0.35 s of residence time in the reactor/contactor.

Chemical absorption of CO2 in alkaline solutions using an intensified reactor

“…Figure 2D). These observations are also in line with the findings of Azizi and Al Taweel [ 21 ] and Altabash et al [ 37 ]…”

“…This approach provides better insights on the evolution of the absorption process than the commonly used two‐point sampling technique, which relies solely on the inlet and outlet concentrations. [ 21,37 ]…”

“…This approach provides better insights on the evolution of the absorption process than the commonly used two-point sampling technique, which relies solely on the inlet and outlet concentrations. [21,37] Due to the short inter-screen spacing and the high flow velocities, nearly plug flow conditions, characterized by low axial dispersion coefficients, prevail inside the reactor/contactor. [38][39][40] Therefore, no slip between the phases is expected to take place, and the equality presented in Equation ( 5) holds true.…”

“…Several authors investigated gas-liquid mass transfer operations in screen-type static mixers. [21,37,48] In all these studies, the mass transfer rate increases with a rise in the flow velocity, although the extent of it is a function of the reactor configuration, screen geometry, and operating conditions.…”

Novelty in fossil fuel carbon abatement technologies in the 21st Century: post‐combustion carbon capture

“…58 Static mixers are being applied in many processes such as waste water treatment process (Formose treatment), gas liquid dispersion, pipeline reactions, biodiesel production and chlorine dioxide bleaching of pulp. 58,60 Altabash et al 61 reported the use of a static mixer for CO 2 capture using water as the solvent. The study showed that the static mixer has the potential for intensifying CO 2 capture either using physical or chemical absorption.…”