The principle of distillation is to use the difference in the volatility of the components in the liquid mixture to partially vaporize the liquid mixture and then partially condense the vapor, thereby achieving the separation of the components contained in it. It is a unit operation of mass transfer separation. It is widely used in oil refining, chemical industry, light industry and other fields.
Molecular distillation equipment, Short path distillation, Alcohol distillation equipment, Essential oil distillation equipment.
1. According to the method: simple distillation, balanced distillation, rectification, special distillation;
2. According to the operating pressure: normal pressure, pressurization, and decompression;
3. According to the components in the mixture: two-component distillation, multi-component distillation;
4. According to the operation mode: batch distillation, continuous distillation.
1. When using a water condensing tube, first slowly pass in cold water from the lower port of the condensing tube, and flow out from the upper port to the water tank, and then start heating. When heating, you can see that the liquid in the distillation flask gradually boils, the vapor gradually rises, and the thermometer reading also rises slightly. When the top of the vapor reaches the mercury bulb of the thermometer, the thermometer reading rises sharply.
2. At this time, decrease the flame of the gas lamp appropriately or reduce the voltage of the heating electric furnace or electric heating mantle appropriately, so that the heating speed is slightly slowed down. The top of the steam stays in place, so that the upper part of the bottleneck and the thermometer are heated, and the temperature of the droplets and steam on the mercury ball reaches balance. Then increase the flame slightly to perform distillation, control the heating temperature, and adjust the distillation speed, usually 1 to 2 drops per second. During the whole distillation process, there should be condensed droplets on the mercury bulb of the thermometer.
3. The temperature at this time is the temperature when the liquid and vapor are in equilibrium, and the reading of the thermometer is the boiling point of the liquid (distillate). The heating flame during distillation should not be too large, otherwise it will cause overheating in the neck of the distillation flask and a part of the liquid vapor will be directly exposed to the heat of the flame, so that the boiling point read by the thermometer will be higher.
4. On the other hand, the distillation must not proceed too slowly, or else the mercury spheres of the thermometer cannot be distilled, and the liquid vapour will be sufficiently infiltrated to make the boiling point read on the thermometer low or irregular.
1) Petroleum refining industry (crude oil → gasoline, kerosene, diesel oil, etc.);
2) Petrochemical industry (separation of basic organic raw materials, petroleum cracking gas, etc.);
3) Air separation (preparation of oxygen and nitrogen);
4) Food processing and pharmaceutical production.
Actually, Fractional Distillation can be regarded as multiple distillations. But there are several differences between them, which can be concluded as follows:
1. Different Purposes
Fractional Distillation is often used to separate components with small boiling point differences, while simple distillation is usually used to separate components with large boiling point difference as well as separate liquids from solid impurities.
2. Different Pros and Cons
Fractional Distillation can purify liquids containing several different components better even though there are small boiling point differences. But it requires more energy, slower and more complex than Simple Distillation. So on the other hand, Simple Distillation is faster and simpler, requiring less energy. But it can only be used for the separation of relatively pure liquids and there should be a large boiling point differences between components. In conclusion, there are various pros and cons between Fractional Distillation and Simple Distillation.
Short Path Distillation
The pressure difference between the boiling film and condensing surface is the driving force of the stem flow, and the minimum pressure will cause the flowing of steam. Under the 1mbar, the operation requires that there is the shortest distance between the boiling surface and condensing surface. The evaporator manufactured based on the principle is known as the short-path distillation. The short-path distillation (molecular distillation) is equipped with a inside condenser which is opposite to the heating surface, and make the operation pressure reduce to under 0.001mbar. Its relative low boiling temperature is very suitable for the material with heat sensitive and high boiling point.
Short Path Distillation Equipment for Sale
Molecular Distillation Equipment
Molecular distillation is also called short path molecular distillation, which is a distillation method under high vacuum. The average free path of the vapor molecules is greater than the distance between the evaporation surface and the condensation surface, so that the difference in evaporation rate of each component in the liquid can be used. Molecular distillation is to separate the mixtures of liquids.