According to the formula of the mean free path of molecular motion, different types of molecules have different mean free paths due to different molecular effective diameters. Different types of molecules have different flight distances without colliding with other molecules after escaping from the liquid surface. The separation effect of molecular distillation is based on the fact that liquid molecules escape from the liquid surface when heated, and different types of molecules have different mean free paths of motion in the gas phase after escaping. Therefore, molecular distillation can be used for the extraction of monoglycerides and oil deacidification.
Conventional distillation is based on the difference in boiling point of different substances, while molecular distillation systems is based on the difference in the mean free path of molecular motion of different substances. (Volatilization) to achieve separation rather than boiling. Therefore, molecular distillation is operated far from the boiling point. For many of the natural properties of the material, these characteristics have a significant protective effect. So short path molecular distillation is widely used in the food industry, below we introduce the steps of deacidification of monoglycerides and oils using molecular distillation:
Production of monoglycerides:
Monoglycerides are monoglycerides, which are important food emulsifiers. The amount of monoglyceride accounts for two-thirds of the amount of food emulsifiers. In commodities, it can play the role of emulsifying, crisping, fluffy, and fresh-keeping, and can be used as a special food additive for biscuits, bread, cakes, candies, etc. Monoglycerides can be prepared by two processes: esterification of fatty acids and glycerol and alcoholysis of oils and glycerol. The raw materials are various oils, fatty acids and glycerol. Monoglycerides synthesized by esterification or alcoholysis usually contain a certain amount of diglycerides and triglycerides, and the purity of monoglycerides is usually 40% to 50%. Molecular distillation technology can be used to obtain a purity of 90%. % of monoglyceride products. This method is the most common and effective method in the production of high-purity monoglycerides in industry, and the obtained monoglycerides meet the requirements of food grade. Molecularly distilled monoglyceride products win by quality, and gradually replace ordinary monoglyceride with low purity and dark color. The market prospect is optimistic. The development of molecularly distilled monoglyceride can bring huge profits to enterprises. Monoglyceride distillation steps:
1. The monoglyceride molecular distillation systems are evaporated from the distillate surface and then cooled immediately to achieve separation.
2. The unreacted glycerol and monoglyceride can be separated in turn by short path molecular distillation.
Deacidification of fats and oils:
In the production process of oil, the crude oil extracted from oil plants contains a certain amount of free fatty acids, which affects the color, flavor and shelf life of oil. The deacidification methods of chemical alkali refining or physical distillation in traditional industrial production have certain limitations. Due to the high acid value of the oil, the amount of alkali added in the chemical alkali refining process is large, and the alkali also saponifies a large amount of neutral oil during the neutralization process with free fatty acids, resulting in a low refining yield; Acids and oils need to be processed at high temperature for a long time, which affects the quality of oils and fats. Some active ingredients will overflow with water vapor, which will reduce the nutritional value of health care.
Deacidification of prickly ash seed oil with different acid values by short path molecular distillation can obtain relatively high yields of light fatty acids and heavy oil fractions, which cannot be achieved by chemical alkali refining or physical distillation. After deacidification by molecular distillation for high-acid oil with an acid value of 28mgKOH/g and 412mgKOH/g, the acid value of the oil dropped to 26mgKOH/g and 38mgKOH/g, respectively, and the extraction rate of the oil was 86%. And 80.9%, there is basically no loss of neutral oil. Therefore, the use of molecular distillation technology has a good effect on the deacidification of high acid value fats and oils, and has broad application prospects.
Advantages of short path molecular distillation apparatus:
1. The degree of separation is higher than that of traditional distillation, and short-path molecular distillation can separate substances that are not easily separated by conventional methods.
2. There is no boiling and bubbling phenomenon, and short-range molecular distillation is free evaporation on the surface of the liquid layer, which is carried out under low pressure. Because there is no dissolved air in the liquid, the whole liquid cannot be boiled during the distillation process, and there is no bubbling phenomenon.
3. It is non-toxic, harmless, pollution-free and residue-free, and can obtain pure and safe products, and the operation process is simple and the number of equipment used is small. Because the short-path molecular distillation has the characteristics of distillation temperature lower than the boiling point of the material, low distillation pressure, short heating time, and high degree of separation, it can greatly reduce the technical difficulty of separation of high-boiling point materials and heat-sensitive materials, and excellently protect the heat-sensitive materials. Feature quality. The molecular distillation equipment is especially used for the extraction of natural health care products, which can get rid of the shackles of chemical treatment methods and truly maintain the characteristics of pure natural.
Precautions for molecular distillation operation:
1. Molecular distillation device needs to strictly control the liquid level of each effect separator to make it in the position required for use.
2. When the crystallized material is easily precipitated in the molecular distillation systems device, the blockage of pipelines, plate evaporators, valves, etc. is easy to occur. It needs to be vacuum pumped or flushed with water regularly to keep it smooth.
3. Regularly adjust the instrument of molecular distillation device to make it sensitive and reliable. If the instrument is found to be out of order, it should be dealt with in time.
4. The molecular distillation unit needs to carry out strict inspection on the equipment and pipelines, especially the sight glass should be replaced in time to prevent accidents caused by corrosion.
5. Before overhauling the equipment, it is necessary to release the pressure and material, and rinse with water to cool down, and remove the residual corrosive liquid in the equipment.
6. The operator should wear protective clothing to avoid personal injury caused by high temperature liquid and steam.