MICROWAVE SYSTEM AND PROCESS FOR EXTRACTION OF ORGANIC COMPOUNDS FROM CANNABIS

Abstract

The present invention provides a containment vessel for cannabis and other plant materials where the microwave radiation pattern of an applicator is contained within the vessel allowing the efficient heating and removal of organic compounds. The radiation pattern is designed to induce a migrating phase boundary that heats the plant material while the containment vessel allows the collection of liquid and vapor phase organic compounds.

Claims

1. A method of direct extraction of organic compounds from plant material comprising the steps of: Placing the plant material in a containment vessel (processing chamber) having a VSWR of less than 1.2 during the extraction; Applying continuous microwave energy from a microwave source to an applicator in the vessel; Directing the energy from the applicator into the plant material in a pattern to cause a migrating phase boundary to pass from the near field to the far field in the plant material; Collecting the organic compounds in vapor phase released from the plant material; Collecting the organic compounds in liquid phase released from the plant material; Monitoring the reflected waves from the vessel back to the source; And terminating the application of microwave energy upon detecting an increase in reflected waves above a set level.

2. The method in accordance with claim 1 wherein the applied energy is at a level to change the phase of each desired organic compound in the plant material.

3. The method in accordance with claim 1 wherein the organic compounds include CBGs.

4. The method in accordance with claim 1 wherein the organic compounds include CBDs.

5. The method in accordance with claim 1 wherein the organic compounds include terpenes.

6. The method in accordance with claim 1 wherein the frequency of the microwave energy is above 2 GHz.

7. The method in accordance with claim 1 wherein the pattern provides uniform heating of the plant material via a migrating phase boundary and avoids the uneven heating of cavity heating.

8. The method in accordance with claim 1 wherein the plant material is placed in the vessel directly from the field without drying.

9. A system in accordance with claim 1 for extracting organic compounds from plant material using microwave energy to heat the plant material comprising a vessel to contain the plant material, the vessel during extraction having a VSWR of less than 1.2 to minimize standing waves at the applied frequency of the microwave energy.

10. The system in accordance with claim 1 wherein the frequency of the microwave energy is above 2 GHz.

11. The system in accordance with claim 1 wherein the power level of the source is determined by the size and configuration of the vessel and the size of the plant material.

12. A method in accordance with claim 1 of direct extraction of organic compounds from plant material comprising the steps of: creating a phase boundary which passes through plant material in a vessel for the extraction of desired organic compounds.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] FIG. 1 is a diagrammatic illustration of the major system components for extracting organic compounds in accordance with this invention;

[0016] FIG. 2 is is a top cut away view of the antenna power pattern in one plane surrounded by a radiation containment vessel.

[0017] FIG. 3 is a cross sectional view of the container shown in FIG. 2, with the top door in the open position.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] The specific embodiments of the microwave extraction system for organic compounds in cannabis are illustrated in the drawings and will be described in detail herein. FIGS. 1 through 3 illustrates the major components of a cannabis microwave extraction system.

[0019] A line voltage or generator 1, or some similar source, supplies electrical power to a power supply 2. A microwave source 3, including for example a magnetron, klystron and /or solid state energy source, provides energy down a transmission path 5. The path may comprise a waveguide or coaxial cable. A circulator 4 may be employed to prevent reflected power from damaging the microwave source. The microwave energy travels through the transmission path to an access port 6 attached to the radiation containment vessel 7. The access port 6 also allows vapors to escape the radiation containment vessel 7 and directs the vapors to a collection system 8. The radiation containment vessel 7 has a removable lid or microwave door 9 that is designed to prevent microwave leakage during operation. In this embodiment, the lid is opened to allow circular bales of hemp directly from the field to be placed into the radiation containment vessel 7. The directional applicator (not shown here) with a selected microwave power pattern 11 is placed in the access port 6. Near the base of the radiation containment vessel 7 is a metal screen 10 that the cannabis rests directly upon. The metal screen separates the hemp bales from a liquid collection system 12 isolated from microwave radiation by the metal screen. Liquid crude CBD oil is collected during microwave heating and removed from the radiation containment vessel 7 via the liquid collection system 12.

[0020] Once the hemp or other biomass is loaded into the radiation containment vessel 7 and the microwave radiation lid 9 has been properly sealed, power is applied to the applicator and a directed beam of microwave energy is launched into the hemp. A migrating phase boundary develops where microwave energy couples into a narrow region of the hemp, determined by the wavelength of the applicator, and heats the water and organic compounds. Compounds such as terpenes and other compounds having a boiling point below that of water, such as CBGs, will first be removed and will be followed by water. Once water is removed, temperature increases to the boiling points of CBDs—approximately 180° C. Once the CBDs are removed and only carbonized plant material remain in the heated region, the permittivity of the material decreases in the near field allowing the phase boundary to migrate further from the applicator and into unprocesses hemp.

[0021] During heating, sensors that are part of the circulator 4 monitor refected power. The radiation containment vessel 7 is designed to minimize reflected power. The goal of this design is to minimizes standing waves by reflected power and to maintain a VSWR of less than 1.2. This allows the even heating of a migrating phase boundary compared with uneven heating in a cavity.

[0022] Volatile organic compounds such as terpenes are collected as vapor in the collection system 8. The collection system 8 can range from a cold trap to reverse distillation of organic compounds. Pressure created by the microwave beam is sufficient to drive volatile compounds from the hemp to the vapor collection system 8. It is also possible to modify the containment vessel to use vacuum or an inert carrier gas such a nitrogen for specific applications.

[0023] It is possible to vaporize all of the organic compounds and to collect the CBGs. Further, the CBDs are collected in liquid form. CBDs typically form what is refered to as a crude oil when heated in a microwave field. Before the beam can heat CBDs past their boiling points, crude oil migrates under gravity, through the metal screen 10, and is collected in the liquid collection system 12. This feature saves power required to vaporize CBDs and perhaps prevents alteration of their chemical composition.

[0024] A preferred embodiment is the microwave induced migrating phase boundary will remove all organic compounds and the containment vessel 7 will collect all organic compounds in the hemp using power, temperature, and pressure controls. The conventional solvent extraction process, whether used solely or combined with microwave heating, is eliminated thereby increasing extraction efficiency and significantly reducing processing costs.

[0025] The processing method using a migrating phase boundary with the containment vessel 7 allows hemp taken directly from the field as bales and processed without any preparation such as drying, common to solvent extraction processes. Not only are processing costs significantly reduced but terpenes and CBGs are preserved with this approach. The high water content of the hemp provides a valuable source of water for the adsorption of microwave energy in the frequency range of 2 gigahertz or higher. The pungent oder on a summer day in a field of hemp is dominanted by terpenes. Harvesting hemp from the field and immediately processing in the microwave system described in this application maximizes the recovery of valuable terpenes. To further enhance terpene recovery, the harvested bales may be wrapped in plastic or placed in refrigerated units to preserve the volatile terpenes before processing.

[0026] A preferred embodiment are sensors to measure direct and reflected power to monitor the migration of the phase boundary and determine when reflective power levels indicate microwave processing is completed. Once the microwave energy has passed through the hemp there will be measurable reflected waves indicating the need to turn off the application of energy. Cavity heating, typical of other microwave related extraction processes, is eliminated by a focused beam inducing a migrating phase boundary. Controlled uniform heating is possible compared with cavity heating with standing waves that result in uneven heating and arcing.

[0027] While the description above contains specificity, this should not be construed as limiting the scope of the invention; but merely as providing illustrations of the presently preferred embodiment of the invention. Although preferred embodiments and method for extracting organic compounds from hemp have been described above, the inventions are not limited to the specific embodiments, but rather the scope of the inventions are to be determined as claimed. For example, the radiation containment vessel design is based on the power pattern of the applicator or antenna. Different microwave power patterns will result in changes in the vessel design in order to match the new power pattern and prevent reflected power.

[0028] For some applications, it may be beneficial to process the cannabis or hemp by reducing the moisture content or milling the cannabis into finer-grain material prior to placing the hemp into the vessel 7. A system to where fine-grain hemp is blown into the radiation containment vessel 7 via small air and or vacuum access ports and using the same ports to evacuate the carbonized plant material after microwave treatment would eliminate the removable lid/microwave door 9.