Several different methods of extraction are utilized in the process of isolating the bioactive components of cannabis plants and removing them from the matrix of the plant. Extraction methods from cannabis are frequently utilized to isolate individual chemicals that are considered to be desirable.
Since the dawn of time, people have harvested the cannabis plant (also known as marijuana and hemp) for its medical properties. Cannabinoids are pharmacologically active substances that have been found in these plants in over one hundred different chemical forms. Terpenes and flavonoids are also present in these plants. Cannabidiol (CBD) and tetrahydrocannabinol (THC) are the two cannabinoids that have garnered the most attention and notoriety (CBD).
CBD does not have euphoric effects, but it has been shown to be effective as an analgesic, antispasmodic, anxiolytic, antipsychotic, antinausea, and antirheumatoid arthritis medication in clinical trials. Because it has psychoactive effects, THC is also used for recreational purposes. It is, however, also an incredibly effective therapeutic substance that is used, for example, by cancer patients to minimize nausea and vomiting as well as pain and to promote appetite. In addition, it helps cancer patients eat more.
Natural cannabis-based preparations, as opposed to any single purified or synthetic cannabinoid, are recommended for use because of the significant synergy that exists between the various cannabinoids and terpenes present in cannabis. Because of this synergy, it is significantly more beneficial to use natural cannabis-based preparations.
In recent years, concentrated extracts of cannabis plants, such as shatter, crumble, budder, wax, and oil, have gained a lot of popularity. This is likely due to the fact that these extracts allow for a variety of convenient routes of administration. Concentrates are substances that are viscous and frequently very sticky, and they can be produced by extraction using solvents such as petroleum hydrocarbons (for example, propane, butane, hexane, petroleum ether, naphtha), subcritical or supercritical CO2, and alcohols. Concentrates can be produced in a variety of ways (e.g., ethanol, isopropanol). After the extraction step, the solvent is evaporated, which results in the production of the “pure” and extremely powerful concentrate.
The use of a solvent is required in several of the more prevalent methods for extracting cannabis. In a nutshell, the cannabis plant material is first soaked in a solvent or a solvent system, after which the plant material is extracted, the liquid is filtered, and the solvent is removed using some sort of evaporation.
It is imperative that, regardless of the method that is used for the extraction, the solvents are removed in order to obtain a highly concentrated extract that is capable of exerting a significant pharmacological effect and can be easily formulated into a drug delivery route. This is because the removal of the solvents is necessary to obtain the highly concentrated extract. When it comes to extracting heat-sensitive chemicals from herbs, there are a few different separation procedures that can be used, including traditional distillation. On the other hand, certain compounds can have high boiling points, which might have a negative impact on the behavior of other compounds.
Distillation method with a low temperature and short contact distance
Low-Temperature Short Contact distillation path is a combination of forced circulation evaporation and the molecular distillation process. It was developed by us at Clean Green Biosystems as a PLC-SCADA-based method for separating the bioactive molecules from herbs and from cannabis. This method is known as the Low-Temperature Short Contact distillation path.
After the Solid-Liquid extraction process is finished, the miscella is put into a tank to be stored. All of the phytochemicals that are found in the cannabis plant as well as the solvent-solvent system are included in this miscella. This miscella is obtained from the evaporation by using a system that consists of a forced circulation evaporator and a molecular distillation apparatus. One may choose to have a system with a single stage, a double stage, or numerous stages, depending on the volume of the miscella.
During the process of forced circulation evaporation, the miscella is pumped through tubes or tube bundles that are contained inside of a shell at a high pressure. This process is known as forced circulation evaporation. In order to heat the miscella that is contained within the tubes or tube bundles, steam is delivered into the calendria. A pump imparts a forward momentum upon the liquid as it travels through the tube. The temperature of the liquid increases as it travels further along the tube, causing it to boil as it nears the top. As a direct consequence of this, the vapor and liquid combination shoots out of the tubes at an extremely rapid rate. The miscella is stirred up in some way by being actively circulated, which results in agitation. As soon as the miscella passes through the tubes and into the vapor head, there is an immediate drop in pressure. This combination is deflected by the deflector, which results in the liquid and vapor being effectively separated. This results in the miscella exploding due to its extremely high temperature. This results in the evaporation taking place.
The vapor travels through the apparatus until it reaches the cyclone separator and then exits through the condenser. The solvents that were collected in this manner are going to be recycled for use in the subsequent extraction cycle. The concentrated liquid is pumped into the pump so that it can undergo more evaporation. After everything else is said and done, the concentrated product is gathered.
It is necessary to keep a sufficient amount of liquid height, also known as “submergence,” above the liquor inlet on the vapor body and above the heat exchanger tubes in order to prevent boiling at the tube surface and prevent mass boiling in the liquor inlet. This must be done in order to stop precipitation in the tubes, which would otherwise cause the heat transmission surface to become fouled.
In order to promote efficient heat transmission, a high circulation rate is given for the tubes, which also ensures proper tube velocity. As a result, the temperature rises will be reduced, which will reduce the extent to which the solution will become oversaturated.
The concentrated miscella that is produced as a byproduct of forced circulation evaporation contains a significant quantity of the phytochemicals found in cannabis. The molecular distillation unit achieves an even higher degree of concentration for this.
The process of molecular distillation is an enhanced kind of vacuum distillation that is carried out using short-path evaporators. Because of the drastic shortening of the distance between the evaporator and the condenser, the pressure drop that occurs is significantly decreased. When heat-sensitive material is exposed to heat for a brief period of time under high vacuum, the rate of decomposition is reduced or eliminated entirely.
When it comes to purifying thermally unstable molecules and related substances that have low volatility and an elevated boiling point, molecular distillation is considered to be the most reliable method of separation and purification. The procedure is distinguished by the brief amount of time spent in the portion of the molecular evaporator that is heated and by the low operating temperature that is caused by the vacuum that is present in the distillation region.
The process of molecular distillation is carried out at a very low pressure in order to ensure that the distance between the hot surface and the surface that is condensing is shorter than the mean free route of the molecules. The volume of miscellanea that needs to be processed determines the number of stages of the molecular unit integration process.
Molecular distillation is utilized on materials that are thermally sensitive and have a high molecular weight (in the range of 250 to 1200). Cannabinoids have a total molecular weight of 628.938, with THC weighing 314.45 and cannabidiol coming in at 314.46. It’s possible that the contact times in commercial units are as little as 0.001 seconds. The film has a thickness of between 0.05 and 0.1 millimeters, and it is produced by appropriate vipers that are rotated on a cylindrical tank.
A feed distributor is a component of a molecular distillation unit. This component ensures that the miscella is distributed evenly as a thin film by the vipers, which in turn enhances the surface area available for evaporation. The evaporated solvent is re-condensed with cooled water in the internal condenser, and the thick and concentrated miscella is then delivered to its destination by way of the vaporizers.
In order to extract additional components, the solvent and solvent system is collected through an external vent condenser and then utilised. After this step, the highly concentrated extract of cannabis is collected for either additional processing or direct use.
Because the total process sequence is carried out at a low temperature and spends a brief amount of time in residence with heating equipment, the extract that is produced using this method is extremely bioactive and keeps the cannabis phytochemicals intact.
PLC-SCADA software is used to control the entire process, including temperature control, flow control, vacuum control, and product viscosity control, among other process control systems.