Silicone Antifoams / Defoamers

Silicone antifoams (silicone defoamers) are polydimethylsiloxane-basednformulations that knock down and prevent foam by spreading a low-surface-tensionnfilm that ruptures the thin liquid walls holding bubbles together. Theynact at parts-per-million, which makes them efficient where foam threatensnthroughput in gas-treating, separation, and water-handling units. The active isnthe silicone; the rest of the formulation controls how it disperses and persistsnin a given medium. Match the form to the system before fixing a dose.

The defoaming power comes from PDMS combined with hydrophobic, surface-treatednamorphous silica. The silica particles concentrate at the foam film and help itncollapse while the silicone fluid spreads. The genuine trade-off is carryover:nsilicone is hard to remove downstream and can deposit on membranes, catalysts, orncoating surfaces, so where silicone contamination is a problem operators choose anpolyether (non-silicone) defoamer instead. Decide by what the stream feeds next.

Form follows the medium. Polyether-modified siloxanes improve compatibility andnspreading and stabilize emulsion grades for aqueous systems such as amine unitsnand produced water; neat fluids and compounds suit hydrocarbon streams. Dose toneffect and no higher, because overdosing silicone antifoam can itself stabilize anfine secondary foam and raises carryover risk. Start low and titrate against thenactual foam height in the vessel.

• Foam control in amine gas-treating (sweetening) absorbers and regenerators
• Antifoam in production separators, treaters, and glycol dehydration columns
• Defoaming in produced-water and process-water handling
• Foam suppression in downstream process units and crude handling
• Knockdown of transient foam during process upsets and chemical injection

• Polydimethylsiloxane u2014 PubChem
• Amorphous silica u2014 PubChem