Hydrodynamic Extraction System

The miscella (oil and solvent) after the extraction of phytocannabinoids from solid-liquid extraction methods of dry cannabis biomass or hydrodynamic methods of extraction of phytocannabinoids from fresh cannabis biomass must be distilled and concentrated (solvent recovery), to get a solvent-free, highly concentrated full-spectrum extract. Also, the full-spectrum phytocannabinoids can be subjected to distillation to remove much of the tetrahydrocannabinol (THC) and produce a broad-spectrum distillate.

At Clean Green Biosystems, we have designed a PLC-SCADA-based method (Programmable Logic Controller-Supervisory Control and Data Acquisition) for separating molecules from cannabis, called Low Temperature Short – Contact Distillation Path, which combines forced circulation evaporation and molecular distillation. View More

Once the extraction is complete (whether solid-liquid or liquid-liquid extraction in case of patented hydrodynamic technology), the miscella (containing the extracted phytochemicals and solvent) is collected in a tank and is subsequently evaporated through a forced circulation evaporator and molecular distillation system. Depending upon the miscella volume that needs to be processed, single, double, or multistage systems may be employed.

The forced circulation evaporation system is composed of shell and tube heat exchangers, a flash evaporator, and primary and secondary condensers. The ASME-compliant shell and tube heat exchangers heat the miscella so that the vapour is created. The primary condenser distils the first-pass vapour whereas the secondary condenser further refines vapour from the primary condenser. This integration helps in efficient recovery of vapours. The forced circulation evaporation system removes around 75-80 % of the solvent from the miscella. The output of this evaporation process is concentrated miscella, which can be further purified using molecular distillation. View More

Thermally unstable compounds can be safely purified or separated by applying molecular distillation methods.

As Phytocannabinoids are higher molecular weight, thermo labile compounds, the application of high vacuum distillation methods, such as molecular distillation, are used to isolate/separate/purify components without thermally degrading them. A molecular distillation unit has a feed vessel that introduces miscella into the unit, whereupon the wipers spread an even coating as a thin film on the heated walls of the unit, thereby increasing the surface area. Specific and proprietary wipers can produce a thin layer of extract that’s 0.05 – 0.1 mm in thickness, significantly enhancing the evaporation surface area. The speed of the wiper blades’ rotation can be optimized and controlled to ensure uniform flow of the miscella for a rapid and efficient evaporation.

Molecular distillation uses short-path evaporators, and the distance (varies with flow and evaporation rates, but typically between 1 and 30 cm) between the evaporator and the condenser minimizes pressure drop. The distance between the heating and cooling surfaces is carefully designed to have a faster, rapid, and efficient separation of solvents from the miscella. The thermally labile molecules have short contact times with heat (may be as low as one millisecond), and thus, decomposition of the molecule(s) is kept to a minimum or does not occur at all. The evaporated solvent is condensed using chilled water, and the thick/concentrated miscella is expelled by the wipers. The solvent/solvent system is collected through an external vent condenser and can be used to extract further materials. The highly concentrated cannabis extract is collected for further processing or for direct use.