Mass transfer and capture of carbon dioxide using amino acids sodium aqueous solution in microchannel

Abstract

Capture and storage of CO2 are important to restrain the greenhouse effect. The amino acid salt solution as a new type of CO2 absorbent shows good application potential. Besides, microchannel has a unique enhancement to mass transfer, which is conducive to promote CO2 capture. The absorption performance of CO2 into aqueous solutions of sodium salts of l-threonine, l-valine, l-alanine and glycine in the microchannel was investigated. It was found that the CO2 absorption rate of four sodium amino acid aqueous solutions under the same condition follows in the order: ñ (sodium glycinate) > ñ (sodium l-alaninate) > ñ (sodium l-valinate) > ñ (sodium l-threoninate). The sodium glycinate aqueous solution has maximum CO2 absorption ability, thus the mass transfer and capture of CO2 absorbed into the sodium glycinate aqueous solution were studied systematically. The effects of operating conditions including gas flow rate, liquid flow rate, and sodium glycinate concentration on the specific surface area, overall volumetric mass transfer coefficient, overall mass transfer coefficient and absorption fraction of CO2 were explored. Furthermore, a new correlation was proposed to predict the volumetric mass transfer coefficient.