Defoamer and its classification

Introduction

Defoamer or antifoam agent is a chemical additive that reduces and prevents the formation of foam in industrial process liquids. The terms antifoam and defoamer are often used interchangeably.

In industrial processes, foams cause serious problems. They cause defects in surface coatings. They prevent containers from filling efficiently. Various chemical formulations are available to prevent foam formation.

Defaming properties

In general, a defoamer is insoluble in the floor environment and has a surface active property. One of the basic features of a defoamer product is low viscosity and the ability to quickly spread on foamy surfaces. This substance has an affinity for the air-liquid surface where it destabilizes the foam layers, this causes the air bubbles to rupture and break the surface, the air bubbles accumulate and the larger bubbles reach the liquid surface faster.

Anti-floor history

The first defoamers were aimed at breaking the visible foam on the surface. To break the foam, kerosene, fuel oil and other light oil products were used. Other vegetable oils also found special use. Fatty alcohols (C7C22) were car defoamers but expensive. They were added to petroleum products to increase efficiency. Milk and cream were emulsion antifoams today.

During the 1950s, experiments with silicone-based defoamers began. These were polydimethylsiloxane based silicone oil dispersed in water or light oil. Silicone oils worked well, but in many applications, such as paints and papermaking, they caused surface disturbances. In 1963, the first antifoams with hydrophobic silica particles (hydrophobic in light oil) were registered. In the early 1970s, hydrophobic waxes such as ethylene bistearate dispersed in oils were developed. These types of defoamers were very effective. But the oil crisis of 1973 It made these very expensive and led to pressure to reduce the oil content, hence oil-in-oil emulsion and water-based oil-in-water emulsions appeared

Development of silicone-based defoamers has continued using various emulsifiers and modified silicone oils. In the early 1990s, silicone emulsion antifoams that caused less surface disturbance were used in the pulp industry.

Development of silicone-based defoamers has continued using various emulsifiers and modified silicone oils. In the early 1990s, silicone emulsion defoamers, which caused less surface disturbance, were used with great success in the wood pulp industry. These resulted in better washing, reduced biological oxygen demand (BOD) in the effluent and reduced scales.

Classification of defoamers

1. Oil-based defoamer
2. powder defoamer
3. water-based defoamer
4. Silicone-based defoamers
5. EO/PO based defoamer
6. Alkyl polyacrylates

Oil-based defoamer

Oil-based defoamers have an oil carrier. This oil may be mineral oil, vegetable oil, white oil, or any other oil that is insoluble in the foam medium except silicone oil. An oil-based defoamer also contains hydrophobic wax or silica to increase performance. Common waxes include Ethylene Base Star Omid (EBS), paraffin waxes, ester waxes, and fatty alcohol waxes. These products may also contain surfactants to improve emulsification and dispersion in the foaming medium. These are heavy-duty defoamers and are usually the best at removing surface foam.

Powder defoamer

Powder defoamers are basically oil-based defoamers on a particle carrier such as silica, which are added to powder products such as cement, plaster, and detergents.

Water based defoamer

Water-based defoamers are different types of oils and waxes that are dispersed in a water base. Oils are often white oils or vegetable oils, and waxes are long-chain fatty alcohols, fatty acid soaps, or esters. These are usually the best as aerators, meaning they are the best at letting air in.

Silicone-based defoamers

Silicone-based defoamers are polymers with a silicone backbone. These may be delivered as oil or water emulsions. The silicone compound consists of a hydrophobic silica to which emulsifiers are added to the silicone oil to ensure that the silicone disperses quickly and well in the foaming medium. The silicone compound may contain silicone glycol. and other modified silicone liquids.

Silicone oils are added to emulsifiers to ensure that the silicone disperses quickly and well in the foaming medium. Silicone formulations may also contain silicone glycol and other modified silicone liquids. These are also heavy-duty defoamers and are good at both removing surface foam and releasing entrained air.Silicone-based defoamers are also suitable in non-aqueous foaming systems such as crude oil and oil refining. be suitable

Defoamer based on EO/PO

EO/PO based defoamers contain polyethylene glycol and polypropylene glycol copolymers. They are delivered as oil-in-water solutions or water-based emulsions. EO/PO copolymers typically have good dispersion properties and are often suitable where deposition problems exist.

Alkyl polyacrylates

Alkyl polyacrylates are suitable for use as defoamers in non-aqueous systems where air release is more important than surface foam decomposition. These defoamers are often supplied in a solvent carrier such as petroleum distillates.

Floor industrial problems

The most noticeable shape is the floating foam on the surface of the stock. It is easy to monitor and relatively easy to work with. Superficial people may cause problems at the liquid level and overflow. This may reduce process speed and process equipment availability.

Defoamer test methods

There are different ways to test the defoamer. The easiest way is to look at the surface of the floor. All that is needed is a system to generate foam. This may be done with a round pumping system with a nozzle and a cylinder or an air injection system into a cylinder. The cylinder has a scale to measure the height of the foam. This equipment may have a heater to control the temperature. The bubbled air can be tested with similar equipment that has a density meter that can record changes in density over time.

Drainage can be tested with a filter system to measure the time it takes for liquid to drain from the filter. The filter may be under pressure or vacuum.

Applications

1_Antifoam in detergents

Antifoam is added to certain types of detergents to reduce foaming, which may reduce the performance of the detergent. For example, dishwasher detergents must have a low lather for the dishwasher to work properly.

2_Antifoam in food

These factors are present in various foods such as chicken nuggets in the form of polydimethylsiloxane, a type of silicone. Oil silicon is also added to cooking oil to prevent foaming in deep frying.

3_Industrial use of antifoam

Defoamer is used in many industrial processes and products, wood pulp, paint, paper, industrial wastewater treatment, food processing, oil drilling, machine tool industry, cutting tools, hydraulic oil, etc.

4_Antifoam in pharmaceuticals

Anti-foaming agents are also sold commercially to relieve flatulence. A familiar example is the drug Simethicone, which is the active ingredient in drugs such as Mylanta Maalox and Gas-x.