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Short Path Molecular Distillation Equipment from China Suppliers & Factory for Thermosensitive Materials
Description
Many materials, such as petroleum heavy residue, chemicals, pharmaceuticals and natural foods, health products, fatty acids, etc., are often thermosensitive, viscous, and/or have high boiling points. To separate these materials from their other components while maintaining the quality of the product, distillation can only be carried out at low or even below boiling temperatures, and thermal decomposition or polymerization can only be minimized in a short period of time to eliminate damage to the product.
When the operating vacuum degree is about 500Pa, it can be carried out in a scraping film evaporator or a falling film evaporator. However, if distillation must be operated under medium to high vacuum conditions (such as pressures between 0.001 and 100Pa), there is a problem. It is necessary to choose an evaporator with a vapor pressure not exceeding the pressure difference between the heating surface and the condensing surface of the product, so evaporators with an external condenser are excluded from the distillation process in the medium to high vacuum range.
In contrast, the SY type short-range evaporator is very suitable for this application, and the condenser is manufactured inside the evaporator, directly located opposite the heated distillation process. Therefore, short-range evaporators are a relatively new separation technology that has not yet been widely applied in industrial production and can solve a large number of separation problems that conventional distillation techniques cannot solve.
Key Features & Technical Advantages
Three Scraper Types
Short range distillers can be divided into three types according to the form of scraper: rolling film, sliding scraper, and hinge scraper. Different scraper types are selected based on the viscosity and processing properties of the material.
Low Temp & High Vacuum
The short residence time and the function of the scraper keep the liquid film on the heating surface for an extremely short time. Low distillation temperature, due to the condenser being directly opposite the heating surface, reduces pressure difference, achieving an extremely high vacuum degree.
Viscosity & Anti-Scaling
The deep immersion of sticky substances and products containing solid scraper blades causes a strong shear and mixing effect, reducing the viscosity of the treated liquid. It is suitable for processing viscosity up to 50Pas and preventing scaling.
The function of the extremely thin distillation liquid level scraper is to scrape the feed liquid into an extremely thin liquid film. Separation is more thorough.
Thermally sensitive materials, high separation ratio, and precise scraper use an extremely thin liquid film evenly distributed on the heating surface, causing the entire heating surface to become wet. This allows for a high boiling separation ratio in the operating unit. This means that more than 90% of the entry in the case is evaporated, and the level of constant residual substances can be achieved.
The pressure difference between the boiling film and the condensing surface is the driving force for the flow of steam, and a small pressure drop can cause the flow of steam. Running at 1mbar requires a very short distance between the boiling and condensing surfaces, and a distiller made based on this principle is called a short-range distiller. The short-range still (molecular distillation) has a built-in condenser located opposite the heating surface and reduces the operating pressure to 0.001mbar.
System Composition & Structure
Short range distiller is a thermal separation process that operates at a pressure of 1~0.001mbar. Its lower boiling temperature makes it very suitable for heat sensitive and high boiling point substances. Its basic composition: cylindrical cylinder with heating jacket, rotor and inner Built in condenser; Accurately install a scraper and anti splash device on the fixed bracket of the rotor. The built-in condenser is located at the center of the evaporator, and the rotor rotates between the cylindrical cylinder and the condenser.
The short-range still consists of a vertically heated cylindrical body, a condenser located in its center, and a rotating scraper between the still and the condenser.
The Distillation Process
1
Material Feeding: The material is added from the top of the evaporator, and is continuously and evenly distributed on the heating surface through the material liquid distributor on the rotor.
2
Film Formatting: The scraper scrapes the material liquid into an extremely thin, turbulent liquid film and pushes it downward in a spiral shape.
3
Evaporation & Condensation: Light molecules that escape from the heating surface condense into liquid on the built-in condenser through a short route and almost without collision.
4
Discharge: Condensed light molecules flow down the condenser tube before being discharged through the discharge pipe located at the bottom of the evaporator; the residual liquid (heavy molecules) is collected in a circular channel under the heating zone and flows out through a side discharge pipe.
Frequently Asked Questions (FAQ)
What materials are suitable for short-range distillation?
It is ideal for thermosensitive, highly viscous, and/or high boiling point materials such as petroleum heavy residue, chemicals, pharmaceuticals, natural foods, health products, and fatty acids.
Why does a short-range evaporator place the condenser inside?
By placing the condenser directly opposite the heating surface, it minimizes the pressure drop between the boiling film and the condensing surface. This design allows operation under high vacuum conditions (0.001 to 100Pa) where external condensers would fail.
What are the different types of scrapers available?
Short-range distillers utilize three main types of scrapers: rolling film, sliding scraper, and hinge scraper. The choice depends entirely on the viscosity and processing properties of the target material.
How does the system handle highly viscous materials?
The scraper blades exert a strong shear and mixing action on the liquid film. This reduces the viscosity of the treated liquid (up to 50Pas) and prevents scaling on the heating surface.
What is the typical operating pressure of a short-range distiller?
A short-range distiller operates at a thermal separation pressure range of 1 to 0.001 mbar. This high vacuum environment significantly lowers the boiling temperature for safe processing.