Surfactants Contamination in Feed Gas Streams to Amine Units, the Phantom Foaming Agent

Production Corrosion Inhibitors and MDEA Solvent Foaming

To determine if upstream process additives can cause amine foaming when they ingress into amine units, a series of production chemicals were evaluated. A group of corrosion inhibitors used by a gas producer were tested for their effect on MDEA amine foaming.  The tests were performed by taking samples of of 50% laboratory grade MDEA diluted in distilled water and adding the individual corrosion inhibitor 0.01%.  A total of 14 different production corrosion inhibitors were tested.  Figure 1 shows the results of the foam tests. The red line is the control sample with no corrosion inhibitor. All 14 corrosion inhibitors produced foaming of the amine solvent.  In fact, most corrosion inhibitors tested formed a stable foam that was persistent for more than one (1) hour time.  This shows that some upstream process additives such as certain corrosion inhibitors can cause complex amine foaming situations, and in some cases quite severe.  These components should not be used upstream of amine units if possible, or alternatively be removed from the feed gas prior to the amine unit using a surfactant separation system.

Figure 1.   Foaming Tests of laboratory grade 50% MDEA in distilled water with added corrosion inhibitor. Each line represents a different corrosion inhibitor used. the red line represents the control sample containing no corrosion inhibitor.

David Engel,Ph.D. - Managing Director

Nexo Solutions

25003 Pitkin Road, Suite A100 - The Woodlands, Texas 77386 USA

david.engel@NexoSolutions.com  

www.NexoSolutions.com