Molecular Distillation Equipment

Content
1. What is molecular distillation equipment?
2. Application of molecular distillation equipment
3. Molecular distillation equipment working principle
4. Molecular distillation equipment process
5. Advantages of using molecular distillation equipment
6. Types of molecular distillation equipment
7. Molecular distillation equipment specifications
8. Precautions for using molecular distillation equipment
9. How to buy molecular distillation equipment?

Catalogue:
    Molecular Distillation Equipment
    Wiped Film Distillation

Molecular distillation equipment, also known as short path molecular distillation, is a relatively new liquid-liquid separation technology that has not yet been widely used in industrial production. Its application can solve a large number of problems that cannot be solved by conventional distillation techniques.
Molecular distillation equipment, also known as short-range distillation apparatus, is a relatively new liquid-liquid separation technology that has not yet been widely used in industrial production. Its application can solve a large number of problems that cannot be solved by conventional distillation techniques.
Short path molecular distillation is a device that integrates a thin-film evaporator and a condenser into one unit. The vapor of the light component is condensed on the condenser built into the short-run evaporator. The path between the evaporating and condensing surfaces is very short so that the pressure drop in the gas phase is very low.

Molecular distillation is especially suitable for distillation of high boiling point materials, heat-sensitive materials and easy oxide materials. Through high vacuum, the boiling point of materials is greatly reduced, so that high boiling point and heat-sensitive materials can be separated at low temperature; through high vacuum, continuous, fast and highly turbulent materials become film, forming surface evaporation, so that easy oxide materials can be separated quickly.

Molecular distillation system is a special liquid-liquid separation technology, which is different from traditional distillation relying on the principle of boiling point difference separation, but relies on the difference of the average free range of molecular movement of different substances to achieve separation.
As the liquid mixture is flowing along the heated plate and is heated, light and heavy molecules will be escaping from the liquid surface and entering the gas phase. Since the free range of light and heavy molecules is different, the molecules of different substances move at different distances after escaping from the liquid surface. By this way, material separation is achieved. The pressure difference between the boiling film and the condensing surface is the driving force for the flow of steam, and for a small pressure drop will cause the flow of steam. Operation at 1 mbar requires a very short distance between the boiling and condensing surfaces, and stills made on this principle are called short-range stills. short path molecular distillation has a built-in condenser on the opposite side of the heating surface and bring the operating pressure down to 0.001 mbar.

The process of molecular distillation equipment can be sent in four steps as follows.
1. Molecular diffusion from the main body of the liquid phase to the evaporation surface
Usually, the diffusion rate in the liquid phase is the main factor controlling the rate of molecular distillation, so the thickness of the liquid layer should be thinned as possible, and should enhance the liquid layer flow.

2. Molecular free evaporation from the liquid layer surface
The evaporation rate rises with the increase of temperature, but the separation factor sometimes decreases with the increase of temperature, so the distillation temperature should be chosen economically and reasonably based on the thermal stability of the processed substance.

3. The molecules fly from the evaporating surface to the condensing surface
Vapor molecules from the evaporating surface to the condensing surface in the process of shooting, may collide with each other, but also may and residual in the two surfaces between the air molecules collision. Because the evaporation molecules are far heavier than the air molecules, and most of them have the same direction of motion, so they collide with each other on the direction of flight and evaporation speed is not much influence. And the residual air molecules between the two surfaces is a messy thermal motion state, so the number of residual air molecules is the main factor affecting the direction of flight and evaporation speed.

4. Condensation of molecules on the condensing surface
As long as there is a sufficient temperature difference between the hot and cold surfaces (generally 70-100°C), and the condensing surface is in a reasonable and smooth form, it is considered that the condensation step can be completed in an instant, so it is important to choose a reasonable condenser form.

(1) Low operating temperature, can greatly save energy consumption
Conventional distillation relies on the boiling point difference of different substances in the material mixture for separation, while molecular distillation relies on the difference in the average free range of molecular motion of different substances for separation, and does not require the material to reach a boiling state, as long as the molecules volatilize and escape from the liquid phase, the separation can be achieved. Since molecular distillation is operated away from the point of boiling, the energy consumed by the product is minimal.

(2) The short heating time reduces thermal damage to heat-sensitive substances
The basic requirement is that the distance between the heating surface and the condensing surface is less than the average free range of the light molecules, which is usually very small, so that the light molecules escape from the liquid surface and are shot to the condensing surface almost without collision. Research measurements indicate that molecular distillation is heated for only a few seconds or tens of seconds, thus avoiding to a large extent the decomposition or polymerization of substances.

(3) Continuous distillation process
High turbulence, high evaporation rate, the membrane is always scraped into a highly turbulent state, increasing the mass and heat transfer, so that the one-step distillation, no circulation

Falling film molecular distillation still
Falling film molecular distillation still for molecular distillation early form, the structure is simple, but because of the liquid film is thick, the efficiency is poor, today the world rarely used. The device is to take gravity to make the material on the evaporation surface into a liquid film descending way. The material is heated, and the evaporated material can be condensed on the condensing surface in the opposite direction. The descending film type device is the early form, the structure is simple, the liquid film formed on the evaporation surface is thicker, the efficiency is poor, now countries rarely use.

Wiped-film molecular still
Wiped-film molecular still uses Smith-type 45° diagonal grooved scrapers, which drive the material downward around the distillation wall, providing a high degree of film mixing through controlled scraper rotation, resulting in effective small active movements of the material rather than passive rolling of the material against the distillation wall. This allows for short and controlled material residence times and controlled film thickness, resulting in excellent heat transfer, material transport and separation efficiency. Scraper molecular distillation equipment separates volatile components from non-volatile components through a gentle process in which the feed liquid flows through a heated cylindrical vacuum chamber, using the scraping action of the feed liquid film.
In addition, this scraper with inclined grooves does not throw the material away from the distiller wall and contaminate the light components that have been separated. Compared with traditional column distillation equipment, falling film distillation equipment, rotary evaporators and other separation equipment, wiped-film molecular still is recognized as much better.

Centrifugal molecular distillation equipment
Centrifugal molecular distillation equipment centrifugal force film formation, thin film, high evaporation efficiency. However, the structure is complicated, and the manufacturing and operation are difficult. The device will send the material to the center of the high-speed rotating turntable, and expand in the rotating surface to form a thin film, while heating evaporation, so that it condenses with the opposite condensing surface, the device is currently the more ideal molecular distillation device. However, compared with the other two devices, requires a high-speed rotating turntable, but also requires a high vacuum sealing technology.
Centrifugal molecular distillation device evaporation rate and separation efficiency is better; materials in the evaporation surface of the heat time is shorter, reducing the risk of thermal decomposition of heat-sensitive substances; material handling capacity is greater, more suitable for continuous production in industry.

Features:
1. Short path molecular distillation equipment is very compact and can distill high-viscosity products with specially designed scraping systems
2. Low operating pressure to lower the boiling point of substances down to 10-3 mbar (0.1 Pa)

1. Molecular distillation equipment and pipelines need to be strictly inspected and probed frequently, especially the sight glass should be inspected frequently and replaced at the right time to prevent accidents caused by corrosion.

2. The liquid level of each effect separator needs to be strictly controlled so that it is in the suitable position required by the process.

3. In the distillation of easy-to-precipitate crystalline materials, pipeline, plate evaporator, valve, and other parts are prone to scaling blockage phenomenon. Therefore, it is necessary to flush with water regularly to keep it open or use vacuum pumping and other measures to remedy the situation.

4. Before the inspection and repair of molecular distillation equipment, release pressure and material, and flush with water to cool down and remove the residual corrosive liquid in the equipment.

If you are interested in our molecular distillation equipment or have any questions, please write an e-mail to [email protected], we will reply to you as soon as possible.