CWCB Expo^SM

In the supercritical fluid extraction (SCFE) process, extraction is carried out by a solvent above its critical pressure and temperature. A brief description of the SCFE process is given below.

The commercial scale SCFE plant has three extractors, two separators, one CO2 hold-up tank and heat exchangers (see enclosed flow diagram). The extraction process works in a closed loop with constant circulation of CO2 in the system. It is a semi-batch operation with typical batch time of 2 to 4 hours. CO2 is liquefied and fed to the hold-up tank through a heat exchanger (Condenser). Liquid CO2 is then fed to the high-pressure metering pump, through a heat exchanger (sub-cooler) to ensure supply of CO2 in liquid form. The high-pressure liquid from the pump discharge is then heated in a heat exchanger (pre-heater) to achieve supercritical temperature. The entrainer pump can be used for dosing a small quantity of other solvents such as water, ethanol etc. in to the CO2 stream, if desired. This supercritical fluid then flows through the extractors. The raw material powder, to be extracted is held in these extractors with help of perforated baskets for easy handling. Extractors are equipped with specially designed quick acting closures for easy and fast opening of extractors. At any given time only two extractors operate in extraction mode, while the third extractor is out of cycle for change of feed. When any of the two operating extractors need feed change, it is taken out of process and replaced by the third extractor having fresh feed. This sequencing continues to minimise the downtime required for feed change. The supercritical CO2 with dissolved extract then flows to separators.

In the separators, lower temperature and pressure conditions are maintained for recovery of the extract from the CO2 stream. Thus with proper selection of conditions, fractionation of extract can be achieved by using two separators operating in series. Separator-1 is maintained at supercritical conditions, where typically high molecular weight components of the extract precipitate. Whereas in separator-2 sub-critical conditions are maintained for complete recovery of any extract from CO2 stream. The CO2 vapour leaving separator-2 is condensed and fed back to CO2 hold-up tank.

When the solid feed in the extractor needs replacement or when plant is to be shut down, respective vessels are depressurised to atmospheric pressure. In doing so maximum possible CO2 is fed back to CO2 hold-up tank through CO2 depressurising line.

Background technology

Cannabidiol is extracted from industrial Cannabis, which is the main active ingredient in cannabine, It has a neuroprotective effect, no addictive and the effect of rheumatoid arthritis and anti- anxiety, caused wide attention in areas such as medicine and become a research hotspot in recent years. At present, the Cannabis oil extraction industry greater extraction with solvent extraction, and some of the existing extraction method to spend a lot of valuable organic solvent, high energy consumption, high extract cost, and there is residual solvent in the extracted cannabidiol, smelly, low purity.

Supercritical CO2 extraction can not only improve the extraction purity and extraction rate of industrial Cannabis oil, but also reduce environmental pollution and extraction cost.

By using supercritical CO2 fluid extraction technology to extract the Cannabis oil from industrial Cannabis,during the extraction, the cooled cannabis powder is put into the material barrel of the extraction kettle.The CO2 gas was injected into the extraction kettle, the temperature and pressure in the extraction kettle were kept in contact with the raw material under the supercritical state of CO2 gas, so that the Cannabis oil and other components in Cannabis powder were dissolved in the supercritical fluid, and the fluid containing cannabinol and other components was expanded from the extraction kettle through throttling to the separation kettle for analysis, and then the Cannabis oil was obtained and collected.

Cannabis Extraction Step

We use supercritical CO2 fluid as the extraction solvent and recycle it in the same system, which not only has simple process and low energy consumption, but also has small consumption of solvent and low price. Therefore, the extraction cost is low, and the extraction cycle is also short, only 1-2h, which is one quarter of the production cycle of the existing technology.And the extracted Cannabis oil has good quality, high purity, no odor, no solvent residue, no environmental pollution and other characteristics.

1. (1) Industrial Cannabis was screened, pre-drying, pulverized, dried and cooled before extraction

(2) During the extraction, the industrial Cannabis powder treated by step (1) was put into the material barrel of the extraction,the CO2 gas was injected into the extraction kettle, the temperature and pressure in the extraction kettle were kept in contact with the raw material under the supercritical state of CO2 gas, dissolve the industrial Cannabis oil rich in cannabidiol in the supercritical CO2 fluid

(3) CO2 fluid with cannabidiol-rich industrial Cannabis oil was expanded from the extraction kettle through throttling to the separation kettle, and the cannabidiol-rich industrial Cannabis oil was analyzed and collected

2. Screening refers to the screening of moldy raw materials in industrial Cannabis

3. Predrying refers to put industrial Cannabis in the oven, drying 10 ~ 12 hours under the 50 ~ 60 ℃ temperature or drying to the water content of industrial Cannabis is not greater than 8%

4. The pulverization, drying and cooling steps are to put the predrying industrial Cannabis into a pulverizer and pulverize it into industrial Cannabis powder of 20-40 mesh: then put the industrial Cannabis powder into the oven and drying 10 to 12 hours at a temperature 50-60℃. The industrial Cannabis powder after drying is left in the drying oven and naturally cooled to normal temperature.

Through the two drying processes of pre-drying and drying, the moisture in the raw material can be greatly reduced, and the conditions for reaching the supercritical temperature and pressure of CO2 can be reduced during the extraction, so that the extraction can be completed at a lower temperature and pressure, which can be efficiently performed. Also the can extend the life of the device. The pulverized material can fully contact with the supercritical CO2 fluid, which can greatly increase the extraction rate.

5. The supercritical temperature is 50~60℃ and the pressure is 30MPa.The flow rate of CO2 gas through the extraction kettle is 150~200kg/h, and the extraction time is 1.5~2h

6. The analytical conditions of the separation kettle were temperature 60~65℃ and pressure 5.0MPa

7. Collection means that the industrial Cannabis oil rich in cannabidiol extracted from the same batch of raw materials is rapidly put into the homogenizer after heating in the range of 70-80℃.After homogenizing filling, keep in cool storage away from light

Cannabis Extraction Process Flow Diagram