VACUUM PUMP IN VACUUM DISTILLATION

The final step in the refining process of liquid products is usually rectification. The main purpose is to maintain the physical and chemical properties of the product. The refining yield of the product is as high as possible. Take the product as the normal distillation, remove the low boiling part as the solvent and the high boiling part as the bottom material, so as to achieve the product quality index. Liquid products are usually thermally sensitive to thermal deterioration, so it is especially important to refine at low temperature.

Similarly, for economic and environmental reasons, the solvent must be recycled. Refining of liquid products requires as high a vacuum as possible, usually operating under 10Pa (one standard atmosphere is 101325Pa). The configuration that satisfies this condition is: slide valve vacuum pump, claw pump two kinds of single pump, roots vacuum unit.

(1) roots vacuum unit

roots vacuum unit operating power is quite high. For the first stage pump to achieve equivalent of claw type pump swept volume of the same unit, the unit with power for 20 Kw, for day and night continuous operation of the vacuum generating device, the difference of 12.5 Kw, of charge of electricity of a year, 90000 yuan means that the gap (work day and night 300 meter per year. The electricity charge is one yuan per degree.

(2) Piston Vacuum Pump

It must have a vacuum pump in order to work effectively. When the gas flows through the vacuum pump, it is hard to avoid the vacuum pump oil out. This means you can't apply the recycled solvent directly, or waste it and pollute the environment. In addition, the operation and maintenance requirements of the slide valve pump are high, in cold season, a little careless switch machine, very easy to damage.

(3) claw type pump

Using claw pump, there is no problem to recover the solvent at normal pressure after pump. In addition, due to its good structure, sophisticated processing and complete ancillary equipment, once put into use, it has low requirements for use, wide range of use, long service life and convenient cleaning and maintenance. When higher vacuum is required, it can be used as the front pump to form the vacuum unit conveniently.

THE APPLICATION OF VACUUM PUMP IN INDUSTRIAL SECTOR

Vacuum pumps are widely used in industrial sectors, such as the manufacture of light bulbs, electronic tubes, food packaging, and semiconductor devices. Vacuum distillation, vacuum impregnation, ion nitriding, vacuum drying, vacuum carburizing, vacuum quenching, vacuum casting, etc. The harmful effects of gas can be avoided under vacuum condition because the number of gas molecules is small.

For example, heat treatment in vacuum can avoid oxidation and gas infiltration into the metallographic structure, so as to improve the quality of parts. Keeping high vacuum in electronic device can avoid the influence of electron motion. Keeping a high vacuum in vacuum packaging can improve the shelf life of food. In the modern advanced science and technology, vacuum technology is an indispensable means, such as high energy accelerator, controlled thermonuclear reaction, space simulation and other engineering needs high vacuum or ultra-high vacuum technology.

Type of vacuum pump:

Gas transfer pump is a kind of vacuum pump that can make the gas inhalation and discharge continuously to achieve the purpose of air extraction. It includes variable capacity and momentum transfer.

1. Variable-volume vacuum pump is a device that USES the periodic change of pump chamber volume to complete the inhalation, compression and exhaust.

2. Momentum transfer vacuum pump is a kind of vacuum pump that USES high-speed rotating blade or high-speed jet flow to transmit momentum to the gas being pumped, so that it can inhale, compress and exhaust.

3. Gas trap pump is a vacuum pump that absorbs or condenses gas on the inner surface of the pump.

Many different kinds of vacuum pump, a mechanical vacuum pump (e.g., reciprocating vacuum pump, oil seal type vacuum pump, roots vacuum pump, turbomolecular pump, water ring vacuum pump, etc.), the jet vacuum pump (water steam injection pump, water injection pump, air injection pump, oil pump, oil diffusion pump, etc.), and physical and chemical adsorption pump (such as titanium pump, molecular sieve adsorption pump, cryogenic pump, etc.). Mainly used in mechanical industry department mechanical vacuum pump, other types of pump is used less.

LIQUID RING VACUUM PUMP IN THE VACUUM DISTILLATION INDUSTRY

Liquid  ring vacuum pump in the industrial production process vacuum distillation is used more, how to choose correctly and use liquid  ring vacuum pump is particularly important. The vacuum distillation is one of the distillation methods. Under reduced pressure, commonly used in separation under atmospheric pressure is easy to decompose when heated to boiling point substances, or combined with other distillation methods such as steam distillation in order to reduce the distillation temperature and improve the separation efficiency. Used for separation and purification of chemical, organic, metal compounds, metal alcohol salts, etc.

Vacuum distillation is also used for deep purification of some special gases. Some compounds have high boiling points. To boil such compounds, it is better to lower the pressure of boiling rather than raise the temperature. Once the pressure is reduced to the vapor pressure of the compound (at a certain temperature), the compound begins to boil and the distillation can proceed. The technology is called vacuum distillation and is commonly used in the laboratory as a vacuum carburetor. This technique is useful for compounds that boil at atmospheric pressure above their decomposition temperature, and any attempt to boil them at atmospheric pressure will break them down.

Want better to use a product will need to have a comprehensive understanding to it, liquid  ring vacuum pump is the same, in order to facilitate everyone to use and improve your product operation proficiency, the next is to introduce the knowledge of vacuum distillation pressure.

1. The common vacuum distillation process of liquid  ring vacuum pump is mostly operated within the pressure range of more than 104Pa. The mechanism of vacuum distillation is similar to that of normal pressure distillation.

2. low liquid  ring vacuum pump vacuum distillation pressure range is 2.7 * 102 Pa, Pa 1.0 gas nearly transition flow state at this time, for the vacuum distillation device type selection, design, manufacture, installation, operation and so on all have more strict requirements.

3. The pressure range of crude vacuum distillation is 1.0*104Pa-2.7x102Pa, and the gas flow is viscous. Distillation within this pressure range is easy to achieve.

4. The pressure range of quasi-molecular distillation in liquid  ring vacuum pump is 1.0-1.0* 10-2pa. At this point, the average free path of gas molecules is similar to that of the distiller, and the gas is in transition flow.

5. The operating pressure of molecular distillation is below 1.33* 10-2pa. In liquid  ring vacuum pump molecular distillation or quasi molecular distillation device, the flow of the gas for the free movement of molecules, that is to say, you can ignore the other molecular collision and interference of the system, at this point, the distillation process governed by evaporation from the liquid surface.

In using the vacuum pump, please pay attention to:

1. What is the required vacuum degree and extraction speed in the vacuum distillation process?

2. Whether the gas pumped is corrosive.

3. Whether the gas pumped has inflammable, explosive and other risks.

4. Pipe connection of the gas pumped.

5. Whether the gas pumped contains condensable gases such as water vapor.