This article mainly introduces the application of the freezing technology crystallization technology of industrial refrigerators in the oil industry and the principle of freezing crystallization. At present, the separation method using freeze crystallization technology in the separation and purification of the oil and fat industry, and its operation and application characteristics.
The process by which crystals form in solution is called crystallization. There are generally two methods of crystallization: one is the evaporation solvent method, which is suitable for substances that have little effect on solubility by temperature. This method is used in coastal areas to "salt". The other is the method of cooling hot saturated solution. This method is suitable for substances with increased temperature and increased solubility. For example, in the northern part of the salt lake, the temperature is high in summer, and no crystals appear on the lake surface; every winter, the temperature decreases, and substances such as rock alkali (Na2CO3 · 10H2O) and thenardite (Na2SO4 · 10H2O) are precipitated from the salt lake. In the laboratory, in order to obtain larger intact crystals, a method of slowly lowering the temperature and slowing the crystallization rate is often used.
The industrial chiller crystallization technology is mainly to cool (freeze) the solution to achieve saturation and produce crystals. This method is used for substances whose solubility decreases with decreasing temperature. For example, the process of removing wax from fats and oils is called dewaxing. Waxes are present in fats and oils, which can worsen the freeze resistance of fats and affect the storage of fats and oils. . The dewaxing process is also a temperature-lowering crystallization process. It is necessary to set a proper temperature-lowering procedure to ensure the complete precipitation of high-melting wax. These chemicals are particularly suitable for separation by freeze crystallization. When the uranium water smelting plant of the nuclear industry uses sulphuric acid to extract uranium from the ore, a back-extraction solution containing uranium is obtained. After uranium precipitation therefrom, a Na2CO3 + NaOH solution containing a large amount of Na2SO4 is generated. In order to recover this alkaline solution, it must be removed Na2SO4, the uranium plant is frozen crystallization. Dewwater mirabilite crystallized at about 0 degrees. After filtration and separation, the obtained lye was returned to production for use. This process recovered the lye to reduce the production cost of the factory, and recovered the useful byproduct mirabilite.
Freeze crystallization technology, as a commonly used separation technology, has the advantages of simple process principles and convenient operation. It has also been commercialized in the oil and other industries, but in order to obtain a good separation effect, many aspects such as solvent properties, temperature, stirring frequency, and crystallization time need to be considered in the crystallization process. On the other hand, if the purity of the product obtained through the freeze crystallization technology is not high, it needs to be combined with other separation methods such as molecular distillation, supercritical extraction, and column chromatography to optimize the process to obtain the final high-purity product.
Lneya's direct-cooling ultra-low temperature chiller, single-fluid low-temperature chiller, refrigerating temperature range from -150 degrees to -5 degrees, for rapid liquid cooling, using secondary subcooling technology, a full set of imported cold controls, rapid cooling, refrigeration The temperature is low, which can meet the needs of different refrigeration temperatures. It is widely used in the low-temperature reaction field of chemical, pharmaceutical, biochemical and other industries. It adopts international brand compressors and single compressor automatic cascade refrigeration technology, which can cool to minus 120 degrees in 3 minutes. The product adopts 7-inch color touch screen display input and temperature curve record. The entire system is a fully-closed system. There is no water absorption during low-temperature operation, ensuring the purity of the cold heat-conducting medium, preventing ice crystals, and improving the life of the thermal fluid, which saves resources and costs for manufacturers.
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