Removal of MDEA foam creators using foam fractionation: Parametric study coupled with foam characterization

• Foam fractionation as a potential technique for contaminants removal from Methyldiethanolamine (MDEA) solutions was investigated.
• The effect of process parameters on foam fractionation performance was studied.
• Industrial corrosion inhibitor was added as model contaminant and foam creator in gas sweetening units.
• Foam fractionation was capable for separating and concentrating surface active contaminates into the foamate.

This work aimed at investigating the use of foam fractionation as a potential technique for contaminants removal from Methyldiethanolamine (MDEA) solutions. Industrial corrosion inhibitor was added as model contaminant and foam creator in gas sweetening units. The foaming tendency of aqueous MDEA solution was reported in terms of foam volume. Foam stability was reported on the basis of the time required for the last bubble to break. The effect of process parameters such as time of foamate collection, flowrate of dispersion gas, initial liquid volume, and corrosion inhibitor concentration on foam fractionation performance was investigated. Surface tension of collected samples from bulk liquid before and after foaming as well as from foamate was measured and correlated with the separation efficiency. Foaming was capable for separating and concentrating corrosion inhibitor into the foamate. The added corrosion inhibitor increased the foam breaking time and volume. Increasing amine volume at the same gas flowrate decreased the contaminants' separation efficiency. The maximum separation was noticed at gas flowrate of 1.0 L/min (0.009 m3/m2 s). The observations of this study show that foam fractionation can be used effectively to remove surface active contaminates from MDEA amine solutions; however, operating conditions should be selected carefully.