Scope ofapplication:
Suitablefor food, fruit juice, beverage, pharmaceutical, as well as chemical, sewagetreatment and other industries. Freezing vacuum concentration technology canmaintain the original flavor and nutrients of food, pharmaceutical, fruitjuice, milk and other products to the greatest extent, reduce the energyconsumption, simple operation and other advantages, so that the food nutritionis preserved to the maximum extent and the original food flavor is maintained.The minimum working temperature is -60 ° C.
The mainprinciple:
Freezeconcentration is performed at a low temperature below the freezing point of thesolution. This is achieved by using the solid-liquid equilibrium relationshipbetween the dilute solution and ice below the freezing point, increasing thesolution concentration and concentrating the solution. The thermaldecomposition of the ingredients in the material and the volatilization of thearomatic substances are avoided, and the original quality and flavor of thefood are fully preserved. Because it is operated at low temperature and normalpressure, it has the advantages of preventing bad chemical changes andbiochemical changes, and small loss of flavor, aroma and nutrition.
Featuresof freezing concentration system:
Comparedwith the evaporation concentration, MVR or multi-effect distillation commonlyused in domestic factories, freeze concentration has the following significantadvantages:
1. Lowoperating cost. Freeze concentration systems only consume electrical energy anddo not require any industrial steam. The energy cost of operation is only 1/5to 1/7 of the evaporation process.
Theenergy consumption (80 Kcal / kg) of frozen ice crystals is only one seventh(1/7) of the energy required to evaporate water of the same quality (540 Kcal /kg).
2. Thesystem occupies a small area. The entire system takes up less space. Save thecost of buildings and land required by users.
3. Longequipment life. Since the freezing and concentrating system operates at low temperature,the degree of corrosion of wastewater to the equipment is minimized. The devicecan be used for a long time.
4. Noscaling. Unlike heating and evaporation, freezing concentration systems do notscale during operation. The problem of fouling is very prominent in the processof evaporation and concentration. It often even affects the continuous normaloperation of the evaporative concentration system.
5. Lowsystem maintenance cost. Refrigeration and concentration systems useconventional refrigeration systems and compressors. Unlike MVR, high-speedsteam compressors are expensive. So maintenance costs are extremely low.
6.The quality of recycled water is high. The water recovered by thefreeze-concentration system is precipitated from the wastewater with tiny icecrystals and has high purity. The water recovered during the evaporation ofwastewater is obtained by secondary steam condensation. However, during thegeneration and condensation of secondary steam, volatile components in thewastewater are entrained.
Applicationindustries:
Juiceindustry
Freezingconcentration is most widely used in the extraction of fruit juice from fruitand vegetable products. China is a big country producing sugar cane. Convertingsugar cane into fruit cane and processing it into sugar cane juice not onlysolves the market of sugar cane, but also meets the growing demand for juice.Sugarcane juice has strong heat sensitivity, and ordinary evaporation andconcentration of sugarcane juice can easily caramelize sugarcane juice and loseits unique flavor. And the quality of sugarcane juice after freezing andconcentration is stable, except that the color, smell, and sweetness are moreintense, other sugar cane juice basically keeps the original flavor beforefreezing and concentration. In addition, using the principle of progressivefreeze concentration to study the characteristics of apple juice freezeconcentration, it was found that the progressive concentration method has agood effect on the concentration of apple juice, and it retains the aromacomponents of volatile substances in the fruit juice. The acidity and vitamin Ccontent of apple juice are not Influence, the sensory quality of theconcentrated product is uniform, and the original flavor of the juice ismaintained.
Brewingindustry
Theadvantages of freezing concentration are particularly applicable to the brewingindustry. This technology can remove turbid polyphenols, tannins and othersubstances while removing ice crystals, thereby reducing the storage volume ofbeer. In particular, the freeze-concentrated beer can be completely restored tothe original beer by using the mixed water technology. In addition, throughfreeze separation experiments on wine, it was found that alcohol and reducingsugars are relatively easy to concentrate and separate in the liquid phase byfreezing. The freeze-concentration technology has improved the quality of drywhite wine, and can better maintain the quality, aroma and nutritional contentof grape juice, increase the sugar content of grape juice, and increase thetitrated acid content by nearly double, but the pH value of juice changes Notobvious.
Teaindustry
Freezingconcentration has great application value in the concentration of teabeverages, which can maximize the protection of nutritional ingredients andflavor substances contained in tea beverages.
Pharmaceuticalindustry
Freezeconcentration has been developed and applied to the pharmaceutical industry, soit opens the door for the development of new products and improved varieties,and saves energy through its efficient processing. The freeze concentration processinstead of the vacuum evaporation concentration can eliminate the alcoholprecipitation process in the manufacturing process of some oral liquids,thereby improving the taste of the oral liquids. In addition,xylooligosaccharide solutions obtained from xylan hydrolysis often requiredehydration and concentration. If it is concentrated by vacuum evaporation, itmay cause coking and degeneration of xylooligosaccharides on the surface of theheating tube, which will reduce the quality of the product. And by studying thegrowth kinetics of ice crystals during freeze concentration of xylooligosaccharidesolutions and the effects of various factors on the distribution ofxylooligosaccharides in the solid-liquid phase, the effects of various factorson the freezing and concentration of xylooligosaccharide solutions bysuspension crystallization method can be oligomeric The development andutilization of the xylose freezing and concentration process provided atheoretical basis.
Environmental protection
The principle of freeze concentration is to condense thewater in wastewater into ice crystals in a refrigeration system. Ice crystalshave a natural exclusivity during the formation process to produce pure solidwater, thereby purifying wastewater. This part of water can be reused to savewater resources in the factory. The volume of concentrated wastewater separatedfrom ice crystals, that is, the volume of concentrated wastewater is greatlyreduced. Depending on the composition of the concentrated wastewater, differentoptions for continued reduction or third-party treatment can be determined.
