What Can Ultrasonic Sonochemical Equipment Be Used For?
When a liquid is treated with high-intensity ultrasound, the sound waves propagating into the liquid medium create alternating cycles of high pressure (compression) and low pressure (sparse), the rate of which depends on the frequency. During low-pressure cycling, high-intensity ultrasonic waves create small vacuum bubbles or voids in the liquid. When the bubbles reach a volume where they can no longer absorb energy, they collapse violently during high-pressure cycling, a phenomenon known as "cavitation." During the explosion, very high temperatures (about 5,000K) and pressures (about 2,000 atm) will be reached locally. The collapse of the cavitation bubbles also results in a liquid jet with a velocity of up to 280 m/s, and the resulting shear force mechanically stirs the liquid to thoroughly mix the reactants.
Therefore, with the cavitation effect of ultrasonic waves in liquids, ultrasonic sonochemical equipment can be applied to extraction, crushing, mixing, emulsification, dispersion, stirring, defoaming and degassing, and accelerating reactions.
Ultrasonic dispersion is based on liquid as the medium, and high-frequency ultrasonic vibration is added to the liquid. Since ultrasound is a mechanical wave, it is not absorbed by molecules and causes vibrational motion of molecules during propagation. Under the cavitation effect, that is, under the additional effects of high temperature, high pressure, micro-jet, and strong vibration, the distance between molecules increases their average distance due to vibration, which eventually leads to molecular fragmentation. The instantaneous pressure released by the ultrasound breaks the van der Waals forces between the particles, making it less likely that the particles will agglomerate together. Compared with conventional dispersion methods, ultrasonic dispersion technology has high efficiency and short time. There are applications in the manufacture of graphene, nanomaterials, oils and paints.
Under the action of ultrasonic energy, two or more immiscible liquids are mixed together, and one liquid is uniformly dispersed in the other liquid to form an emulsion-like liquid. This process is called ultrasonic emulsification. The biggest feature of ultrasonic emulsification is that no emulsifier is required. In addition, ultrasonic emulsification can control the type of emulsion, and the formed emulsion is more stable, and some are stable for several months to more than half a year; the prepared emulsion has a high concentration, the concentration of pure emulsion can exceed 30%, and the added emulsifier can reach 70%; Phacoemulsification can also prepare emulsions that cannot be prepared by conventional methods. For example, the common mixing method can only produce a 5% paraffin emulsion in water, while it is incredible that a 20% paraffin emulsion can be produced under the action of a power ultrasonic field. The emulsification ability of ultrasonic emulsification equipment in the laboratory has been well known and used for a long time, and is used in the industry for high-efficiency emulsification of mass production in production plants, such as cosmetics and skin care products, pharmaceutical ointments, paints, lubricants and fuel etc.
Ultrasound can better penetrate into plant tissue and improve mass transfer, and cavitation generated by ultrasound can disrupt cell walls and facilitate the release of matrix components. Ultrasonic extraction is not easily limited by the use of solvents, allowing the addition of co-extractants to further increase the polarity of the liquid phase and improve extraction efficiency; compared with supercritical CO2 extraction and ultra-high pressure extraction, ultrasonic extraction equipment is simple and the extraction cost is low ;Different from the traditional boiling method or reflux method, ultrasonic extraction does not require heating, so as not to damage the active ingredients when heated for a long time, it is especially suitable for the extraction of heat-sensitive substances; ultrasonic extraction technology improves the extraction rate of active ingredients and ensures the ideal of raw materials. The use of A, reduces the consumption of solvents and can achieve significant economic benefits; ultrasonic extraction technology has little effect on the activity of active ingredients. Essential oils, Chinese medicine material processing and other industries have applications.
4. Degassing and defoaming
Ultrasonic defoaming is an application of ultrasonic sonochemical treatment, which uses the "cavitation" effect of ultrasonic waves in the liquid to discharge the bubbles in the liquid to achieve the purpose of improving the quality of the solution. Compared with conventional methods, ultrasonic defoaming technology requires no defoamer, has high efficiency and short time. Compared with other processes, it does not require high temperature and high pressure, with good safety, simple operation and convenient maintenance. It has a broad spectrum and wide applicability, and most liquids can be degassed and defoamed by ultrasonic waves. The process is simple, it is not easy to cause pollution, and the temperature is low, which is suitable for the operation of heat-sensitive target components. Compared with the conventional method, the ultrasonic equipment is simple, the production cost is low, and the comprehensive economic benefit is remarkable. It has applications in cosmetics, food and other industries.
Ultrasonic fragmentation utilizes the principle that ultrasonic waves rapidly and alternately compress and expand when they encounter an object. Under the action of ultrasonic waves, when the material is in the half cycle of expansion, the material liquid is expanded by bubbles under the action of pressure. When in the half-cycle of compression, the bubble contracts. When the pressure change is large and the pressure is lower than the low pressure, a "burst" phenomenon occurs in the raw material liquid when the compressed air bubbles collapse sharply. This phenomenon disappears with changes in pressure and imbalances in external pressure. In the instant the "burst" disappears, the area around the liquid causes a significant increase in pressure and temperature. resulting in fragmentation.
An important application of ultrasonic technology is to disperse and depolymerize solids in liquids to achieve the purpose of stirring. Ultrasonic stirring technology has been widely used in food processing, papermaking, paint, chemical, pharmaceutical, textile, petroleum, metallurgy and other industrial fields. Ultrasonic equipment can be easily installed on existing production lines, which is convenient for manufacturers to upgrade at a lower cost equipment.
7. Mix and homogenize
When these small bubbles produced by ultrasonic "cavitation" in the liquid rapidly collapse, high temperature and high pressure are generated in the bubbles, and because the liquid around the bubbles rushes into the bubbles at a high speed, a strong micro-jet is generated in the liquid near the bubbles. Local high temperature and high pressure are formed, resulting in the effect of mixing and homogenization. Ultrasonic mixing and homogenization technology has been widely used in food processing, papermaking, coatings, chemicals, pharmaceuticals, textiles, petroleum, metallurgy and other industrial fields. Cost to upgrade equipment.
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