Modeling investigation of mass transfer of gas–liquid concurrent flow processes

This paper presents a modeling investigation of mass transfer of gas–liquid concurrent flow processes to explore the effect of bubble scale. CO2 capture with MEA aqueous solution is selected as a working system to evaluate the modeling results. The rate-controlling step is first determined and the effects of bubble size, gas–liquid volume ratio and diffusion coefficient on mass transfer coefficients are respectively discussed, with bubble size ranging between 10 μm and 1 cm and gas–liquid volume ratio ranging between 6.5:1 and 321:1. For both gas-resistance-controlled and liquid-resistance-controlled processes, as bubble size decreases from 1 cm to 10 μm, the overall mass-transfer coefficient increases by three orders of magnitude and volumetric mass-transfer coefficient increases by six orders of magnitude, indicating the decrease in bubble size intensifies the mass transfer processes both by reducing mass transfer resistance and increasing interfacial area obviously. The modeling results are in good agreement with the experimental data. This study could be useful for designing micro-devices and optimizing gas–liquid microdispersion processes.

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► A modeling investigation of mass transfer of gas–liquid concurrent flow processes.
► CO2-MEA system is selected as a working system to evaluate modeling results.
► The rate-controlling step is determined by comparing mass transfer rates.
► The effects of bubble size on mass transfer characteristic is discussed.
► The modeling results are in good coincidence with experimental data.