Short Path Distillation Parts

What is short path distillation parts?

Short path distillation parts (also known as molecular distillation) is a thermal separation process dedicated to the separation of heat-sensitive products. Short-path distillation is characterized by short product residence time and low process evaporation temperature, and strives to make the thermal stress on the rectified product as small as possible. It can be seen that short-path distillation is a very gentle distillation process.
 
Short path distillation parts are equipped with a vacuum system that can significantly reduce the boiling point of the product by reducing the operating pressure. This is a continuous separation process with product residence times as low as tens of seconds (versus hours required by other traditional separation methods!).
 
Therefore, products decomposed due to high temperature and long residence time in conventional distillation processes (whether continuous circulation, membrane distillation or batch distillation) can be successfully separated. For example, when high-molecular organic compounds are separated by conventional distillation methods, higher process temperatures (for example, exceeding 200 °C) will lead to thermally sensitive molecular chain scission. Therefore, the separation of high-molecular organic matter almost always uses short path distillation parts.

 

The process of Short path distillation parts:

1. Molecules diffuse from the liquid phase body to the evaporation surface

Usually, the diffusion speed in the liquid phase is the main factor controlling the molecular distillation speed, so the thickness of the liquid layer should be reduced as much as possible and the flow of the liquid layer should be strengthened.
 

2. Free evaporation of molecules on the surface of the liquid layer

The evaporation rate increases with the increase of temperature, but the separation factor sometimes decreases with the increase of temperature. Therefore, the thermal stability of the substance should be taken as the premise to choose an economical and reasonable distillation temperature.
 

3. Molecules fly from the evaporating surface to the condensing surface

In the process of flying from the evaporating surface of the molecular still to the condensing surface, the vapor molecules may collide with each other or with the air molecules remaining between the two surfaces. Because evaporated molecules are much heavier than air molecules, and most of them have the same direction of motion, their own collisions have little effect on the direction of flight and evaporation speed. The residual gas molecules are in a chaotic thermal motion state between the two sides, so the number of residual gas molecules is the main factor affecting the flying direction and evaporation speed.
 

4. Molecules condense on the condensation surface

As long as there is a sufficient temperature difference between the hot and cold sides of the molecular still (generally 70~100°C), and the form of the condensation surface is reasonable and smooth, the condensation step can be completed in an instant, so it is very important to choose a reasonable form of condenser.

Advantages of Short path distillation parts at a glance:

1. Scope of free use:

Vacuum pumps and Roots pumps with different pumping capacity can be combined to meet almost any process requirements of short-path distillation:
 
Steam booster pump for high pumping capacity at high operating pressure (e.g. 1 mbar)
 
Backing pumps such as EDS, EDP, CDX can meet the process of pumping speed up to 1000 m3/h
 

2. Stronger working ability

Designed with mature vacuum pump principles, Edwards vacuum pumps have further enhanced liquid/solid handling capabilities, so they can smoothly deal with deposited particles or liquid agglomerates on the surface of the condenser, such as oil, resin, polymer, etc.
 

3. The environmental protection function is in place

The FBL vacuum system has the function of trapping and treating harmful exhaust gas. It uses advanced exhaust gas management technology and uses an exhaust gas condenser to remove harmful condensable gases in pump exhaust.
 

4. Effective temperature control

The temperature control function can keep the temperature of the process gas in the ideal range, so as to minimize the condensation and corrosion of the process gas. The CXS has an integrated temperature monitoring system, which can accurately control the temperature according to the needs. The EDS and EDP have an easy-to-operate cooling configuration, which can Suitable for cooling water sources with harsh processes and poor water quality.