What are the various types of defoamers composed of?

Detergents are generally made by multi-component blending. The performance of the main defoaming agent can be enhanced through the blending of surfactants. Whether a specific substance is suitable for demulsification depends on its application conditions. For instance, polyether acts as a defoamer under acidic or alkaline conditions; however, it becomes a foaming agent under slightly alkaline conditions. It is effective at low temperatures but becomes ineffective at high temperatures.
Firstly, it is the fermentation defoamer. The fermentation defoamer is a defoamer designed specifically for fermentation processes, which is divided into: oil-soluble defoamer and composite raw oil defoamer. It is used for demulsification in various fermentation processes, such as erythromycin, josamycin, avermectin, gentamicin, cephalosporins, sodium citrate, lysine, and yeast production, which are the main fermentation demulsification processes. It is also applied in feed processing and later-stage recovery processes.
Next, silicone defoaming agents. If the silicone material is usually diluted, it typically consists of substances like crude oil organic solvents, xylene, and water-soluble ones can be diluted with water. Generally, pure silicone materials have a slight polyether odor, a mild刺激性 taste. If you detect the smell of automotive gasoline or xylene, it can be determined as a diluted solution. If unsure, test for volatiles by taking an adequate sample, place it in a high-temperature-resistant container, heat it to 130 degrees Celsius, and bake for 30 to 45 minutes. If the detected volatiles exceed 5%, it can be deemed a diluted solution.
(1) Antifoaming Agent Addition Points: In paper mills, antifoaming agents are typically added during the bleaching and washing stages, usually in the washing machine, concentrator, and pulp pond. In the papermaking section, the antifoaming agents are generally added to the pulp box of the paper machine, pulp pond, sizing, and calender extrusion areas.
(2) Foam stabilizer dosage: Generally, using two types of foam stabilizers is more cost-effective than using a higher concentration version, applying them separately at distant locations. For instance, one foam stabilizer is added before the pulper, and another water treatment foam stabilizer is added to the slurry box.
(3) Solution for Defoamer Sedimentation: Amide-type defoamers, for instance, can lead to sedimentation and blockage of sieve plate gaps, causing paper defects such as multiple fish eyes due to poor dispersion. Some defoamers can also cause interference with胶调胶、提高等 processes. Therefore, high-humidity emulsion systems with both high and low viscosities in calendering architectural coatings exhibit excellent emulsion-breaking properties.
Now, industrial-grade defoamers are commonly used in industries such as food, architectural coatings, and petrochemical equipment, with significantly different types of defoamers used across various sectors. Since defoamers are primarily liquids and come in bottles, many people consider industrial defoamers to be hazardous materials.