4 Main Causes for Foaming in Sour Gas Processing

Foam forms when gas bubbles get stabilized by contaminants in the amine liquid. A clean amine solution won’t foam on its own– the culprits are various surface-active contaminants common in Alberta’s sour gas operations. Based on industry research and field experience, the most frequent foaming triggers are

1- Hydrocarbon liquids

Condensate or lubricating oil entrained in the feed gas or condensing in the contactor can lower surface tension and promote stable foam. Many of Alberta’s gas wells produce natural gas liquids that can slip into the amine contactor if upstream separation isn’t perfect.

2-Water-soluble surfactants

Production chemicals (e.g. corrosion inhibitors, well-treating compounds, or even excess antifoam additives) often contain surfactant ingredients. These chemicals are widely used in Western Canada’s oil & gas fields and can carry over into the amine unit, drastically increasing foaming tendency. (Ironically, overdosing an antifoam can turn it into a foam promoter!)

3- Amine degradation byproducts

Oxygen ingress or acidic gases can form heat-stable salts and organic acids in the amine. These byproducts act as foam promoters, especially in high-temperature regenerators. They’re a common issue in many Alberta plants that run rich amine loads for deep H₂S removal.

4-Solid particulates

Fine solids like iron sulfide (FeS) from corrosion, pipeline dust, or mill scale don’t cause foam by themselves, but they stabilize any foam that does form. Alberta’s older sour gas infrastructure often sheds such particulates, which then accumulate in the amine and make foams more persistent.

Additionally, seasonal operating practices in Alberta can introduce foaming risks. For example, injecting methanol into gas streams to prevent winter freeze-ups is routine – but if that methanol enters the amine system, it can contribute to foaming. Lab studies show that adding methanol to an already contaminated amine (one containing degradation acids) significantly increases foam height and stability. In other words, a combination of factors (e.g. a dirty amine plus a new chemical additive) often pushes systems into a foaming regime.

There are many potential foaming triggers lurking in Alberta’s gas streams and amine circuits. It’s often impossible to predict foam issues just by chemical intuition. Even additives marketed as “clean” or previous experience with one gas stream might not translate to another. That’s why proactive testing for foaming propensity is so critical.

Have questions or need guidance?

Our technical support team (with local Alberta experience) is here to help. Feel free to contact us for recommendations on what samples to test or to discuss your particular foaming concerns. We’re passionate about keeping Alberta’s gas plants foam-free, safe, and profitable.