Industrial Defoaming Methods: Physical & Chemical Approaches

Industrial Defoaming: Principles and Methods

Foam formation during industrial production can cause operational challenges and reduce efficiency. Therefore, factories employ various methods to eliminate foam.

Key Principle of Foam Destruction

To destabilize foam, we must either alter foam-forming conditions or eliminate stabilizing factors, leading to two main approaches: physical and chemical defoaming.

1. Physical Defoaming Methods

Physical defoaming modifies foam conditions without changing chemical composition, including:

• Mechanical agitation (e.g., stirring, shear force)

• Temperature/pressure adjustment (thermal or vacuum defoaming)

• Ultrasonic treatment (cavitation-induced bubble collapse)

Applications:
✔ Suitable for food processing, wastewater treatment, and fermentation where chemical additives are restricted.

2. Chemical Defoaming (Defoamers/Antifoams)

Chemical defoaming involves adding agents that disrupt foam stability by:

• Reducing liquid film strength in bubbles

• Lowering surface tension at gas-liquid interfaces

Properties of Effective Defoamers:

• Strong surface tension reduction

• Easy adsorption on foam surfaces

• Weak intermolecular interactions (loosely packed molecular structure)

Common Defoamer Types (Mostly Nonionic Surfactants):

• Alcohols (branched-chain alcohols, e.g., 2-ethylhexanol)

• Fatty acids & esters (e.g., glycerol monostearate)

• Polyamides & phosphate esters

• Silicone oils (e.g., polydimethylsiloxane)

• Nonionic surfactants (effective near/above their cloud point)

Applications:
✔ Widely used in paints, adhesives, oil refining, and detergent production.