Molecular distillation is a type of short-path vacuum distillation, characterized by an extremely low vacuum pressure, 0.01 torr or below, which is performed using a molecular still. It is a process of separation, purification and concentration of natural products, complex and thermally sensitive molecules for example vitamins and polyunsaturated fatty acids. This process is characterized by short term exposure of the distillate liquid to high temperatures in high vacuum (around 10−4 mmHg) in the distillation column and a small distance between the evaporator and the condenser around 2 cm. In molecular distillation, fluids are in the free molecular flow regime, i.e. the mean free path of molecules is comparable to the size of the equipment. The gaseous phase no longer exerts significant pressure on the substance to be evaporated, and consequently, rate of evaporation no longer depends on pressure. The motion of molecules is in the line of sight, because they do not form a continuous gas anymore. Thus, a short path between the hot surface and the cold surface is necessary, typically by suspending a hot plate covered with a film of feed next to a cold plate with a line of sight in between.

This process has the advantages of avoiding the problem of toxicity that occurs in techniques that use solvents as the separating agent, and also of minimizing losses due to thermal decomposition. and can be used in a continuous feed process to harvest distillate without having to break vacuum.

Molecular Distillation Units 


Short Path Glass Wiped Film Evaporator CBD Molecular Distillation Machine


  • All Borosilicate 3.3 glass design for a perfect view on the separation process.
  • Short residence time(separation is finished in seconds, instead of hours.).
  • The very low operating pressure ensure very low distillation temperature  and therefore a very gentle distillation is possible.
  • Various size options(80mm,100mm,150mm) for different throughput).
  • Turkey package which is plug-and-play, technical supports available.
  • The system can be upgraded for continuous distillation process.
  • Industrial grade stainless steel model are available upon request.

Cannabis Distillation Equipment

Molecular distillation equipment or short path distillation equipment is very efficient for cannabis distillation. At Lab1st, we offer you the Falling Film Evaporator for producers of high grade CBD and THC concentrates for dab, shatter, hemp, cannabis and other forms.

Material is delivered from a feed flask into a columniform evaporation section, getting heating, on the outside, (circulating hot fluid jacket type), and a slotted wiper mechanism forcing liquid around and downward in a thin film on the inside. In the center of the body is a wiped film evaporator with internal cooling condenser, providing a short path for vapor molecules traveling from the heated surface to the condenser surface. For cannabinoids, the internal condenser fluid must be kept elevated (~80°C) to prevent high viscosity or freeze up of THC, CBD and related components. During the itinerary downward, lighter (lower boiling point) fractions of the liquid begin to vaporize, move to the internal condenser and condense, falling down as a liquid into a vessel that catches and separates the distilled liquid (cannabinoid) which flows into a receiver flask. Heavier residue material (Chlorophyll, salts, sugars, heavy wax fractions) does not evaporate and instead travels through the still body and flows into a different receiver flask.

Technical Drawing


Feed Rate (kg/hr)1.0-201.5-302.5-403.5-70
Estimate Throughput at End of 8-10 hr/day for CBD (kg)8122028
Effective Evaporationn Area (m2)
Motor Power (W)120
Maximum Speed (rpm)350
Barrel Diameter (mm)80100150200
Feeding Funel Volume (L)1235
Dimension (DxWxH mm)2120x1740x6282120x1740x6282270x228x19402420x2040x628
Internal Condenser Area (m2)
Jacketed Feeding Vessel Volume (L)1235
Distillate Receiving Vessel Volume (L)1255
Residue Receiving Vessel Volume (L)1135
Stirrer SealOil-less Magnetic, High Vacuum
WiperPTFE Scraper
Structure MaterialBorosilicate Glass 3.3
Vacuum GaugePirani Style
Operation TemperatureUp to 250℃
Vacuum LevelBetter than 10 Pa
Voltage220V-single Phase

How Molecular Distillation Works

Molecular distillation is a special kind of liquid – liquid separation technology. It is different from steam distillation, which relies on the separation principle of difference of boiling point. While Molecular distillation relies on the difference of the average free path of molecular movement of different substances to achieve separation.

Under ideal condition, getting the liquid mixture flowing through the heating plate to heat, light and heavy molecules will escape from liquid level, and enter into the gas phase. Due to the light and heavy molecular free path is different, after different material molecules escape from the liquid level, their moving distance is different. If set up a cold condenser plate properly, then light molecules reach condensation plate be condensing exhaust, and heavy molecules can’t reach condensation plate, the exhaust along with the mixture liquid. In this way, the purpose of material separation is achieved.

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