We, at Clean Green Biosystems, developed a PLC-SCADA based method of separating the bioactive molecules from herbs and from cannabis, a method called Low Temperature Short Contact distillation path, which is combination of forced circulation evaporation and molecular distillation process.
Once the Solid-Liquid extraction is completed or Liquid – Liquid extraction in case of patented technology,the miscella is collected in a tank. This miscella contains all the phytochemicals of cannabis plant and the solvent/solvent system. This miscella is taken for the evaporation through forced circulation evaporator and molecular distillation system. Depending upon the miscella volume, one can have single stage, double stage or multiple stage system.
In forced circulation evaporation the miscella is circulated through tubes or tube bundles which are enclosed in a shell at high pressure by means of a pump. Steam is introduced in to the calendria to heat the miscella in the tubes or tube bundles. Pump sends the liquid to the tube with a positive velocity. As the liquid move up through the tube it gets heated and begins to boil. As a result, the vapour and liquid mixture rushes out of the tubes at a high velocity. Forced circulation of the miscella creates some form of agitation. When the miscella leaves the tubes and enters the vapour head, pressure falls suddenly. This mixture strikes the deflector in effective separation of liquid and vapour. This leads to the flashing of super heated miscella. Thus the evaporation is effected.
The vapour enters the cyclone separator and leaves the equipment through a condenser. The solvents thus collected shall be re used for next cycle of extraction. The concentrated liquid enters to the pump for further evaporation. Finally, the concentrated product is collected.
The output of forced circulation evaporation is concentrated miscella, which contains high amount of cannabis phytochemicals. This is further concentrated in the molecular distillation unit.
Molecular distillation is an advanced vacuum distillation method performed by short-path evaporators. Distance between evaporator and condenser is extremely reduced which results in minimized pressure drop. Heat sensitive material meets heat for a short time under high vacuum, thus low or no decomposition occurs.
Molecular distillation is considered as the safest mode of separation and to purify the thermally unstable molecules and related compounds with low volatility and elevated boiling point. The process distinguishes the short residence time in the zone of the molecular evaporator exposed to heat and low operating temperature due to vacuum in the space of distillation.
The molecular distillation process is carried out at a very low pressure so that the distance between hot and condensing surface is less than the mean free path of the molecules. The number of stages of molecular unit integration depends on the volume of miscella to be processed.
Molecular distillation is applied to thermally sensitive high molecular weight materials (range of 250 – 1200). Molecular weight of cannabinoids is 628.938; THC 314.45, Cannabidiol 314.46) The contact times in commercial units may be low as 0.001 seconds. The film thickness is of the order of 0.05 – 0.1 mm which is created by suitable vipers which are rotated on the cylindrical vessel.
A molecular distillation unit has a feed distributor, which distributes the miscella evenly as a thin film by the vipers, which increases the evaporation surface. The evaporated solvent is condensed in the internal condenser using chilled water and the thick/concentrated miscella is sent out by means of the vipers.
The solvent /solvent system is collected through a external vent condenser and used to extract further materials. The highly concentrated cannabis extract is thus collected for further process or for direct usage.
This method gives a highly bioactive cannabis extract which contains intact cannabis phytochemicals as the over all process sequence is done in low temperature and short residence time with heating elements.
The entire process is controlled by PLC-SCADA software with all process control systems like temperature control, flow control, vacuum control and product viscosity.