1.1 Dispersion: An important indicator to measure the quality of a defoamer is its dispersion effect. Only substances with low solubility and high dispersibility can become the active ingredients of defoamers. As the main component of defoamer, simethicone has low solubility and low dispersibility. It must use white carbon black, emulsifier and other dispersing aids to improve its dispersion effect. Vapor-phase white carbon black is divided into hydrophilic type and hydrophobic type. The hydrophilic type contains silicon-hydroxyl bonds, which can form hydrogen bonds with water molecules. It can be used in water systems to promote the dispersion and stability of defoamers. Hydrophobic vapor phase silica is obtained by surface chemical treatment of hydrophilic silica to reduce the Si-OH number of the silica to an appropriate level. It can also be used in water systems to reduce the amount of silica in the water. The degree of association of the system to achieve the best defoaming effect. The application of fumed white carbon black in defoaming agent is to first make it and dimethyl silicone oil into white carbon black silicone paste, which can improve its wettability with dimethyl silicone oil and dispersibility in silicone oil. The mixing method of the silicone paste has a certain effect on the stability and defoaming performance of the silicone paste. When using hydrophilic white carbon black, due to the low compatibility of inorganic white carbon black and silicone oil, in order to achieve the purpose of mixing, put the silicone oil and white carbon black in a kneader and mix them at 150~180℃ N2 is stirred for 2-7h to improve the wettability of white carbon black and silicone oil. If hydrophobic white carbon black is used, since the surface has been treated with organic matter, its affinity with silicone oil is greatly improved. It can be stirred at 150°C for 2 to 5 hours with N2. The silicone paste made of fumed silica is transparent or translucent, and the ratio is generally silicone oil: silica = (90～95): (10～5), dimethyl silicone oil is generally selected at 25℃, 500～1000cp Silicone oil and white carbon black can be selected with a specific surface area of 200m2/g or more (BET method). As the active ingredient of the silicone oil defoaming agent, the silicone oil paste can be used directly or diluted with a solvent, or self-emulsified with an emulsifier or polyether modified silicone oil to achieve the purpose of defoaming. Due to the presence of SiO2 particles, the silicone oil can quickly spread in the foaming liquid, which improves the dispersion efficiency of the silicone oil, thereby improving the defoaming effect. Therefore, fumed silica is used as a very important dispersant in defoamers.