Foaming Behavior in CO2 Absorption Process Using Aqueous Solutions of Single and Blended Alkanolamines

This work provides a comprehensive investigation on the effects of process parameters on foaming behavior in the carbon dioxide (CO2) absorption process using aqueous alkanolamine solutions, particularly for the application of postcombustion flue gas treatment. The foaming tendency of this process was experimentally evaluated using the pneumatic method modified from ASTM standard, and reported in terms of foaminess coefficient (Σ). Results reveal ranges of solution volume and gas flow rate leading to constant values of Σ. Σ increases and eventually decreases with alkanolamine concentration and CO2 loading. A higher solution temperature reduces Σ. Most tested degradation products and corrosion inhibitors enhance foaming tendency. Monoethanolamine (MEA), methyldiethanolamine (MDEA), and a blend of MEA + 2-amino-2-methyl-1-propanol (AMP; 2:1 mixing ratio) tend to foam, whereas diethanolamine (DEA), AMP, and blends of MEA + MDEA, DEA + MDEA and MEA + AMP (1:1 and 1:2 mixing ratio) do not. Surface tension, vis...