Table of Contents
THC (Tetrahydrocannabinol) extraction from the cannabis plant matter is the goal of all extraction processes. The final result is an oil with concentrated cannabinoid (THC in Cannabis) extracted from the plant biomass.
Since the precious oil is soluble in alcohol (ethanol) and solvents (hydrocarbons), these are the primary media of extraction utilized by most THC processors from the cannabis industry.
Separation of the biomass from the solvent post-extraction needs centrifuge extraction equipment. Low-rpm (low g-force), basket-type centrifuge work for batch processing in ethanol extraction.
Though it is a laborious and inefficient process, it is attractive for its lower initial cost. At higher volumes, the solvent losses in this batch method add up quickly.
A cannabis extraction centrifuge is an industrial centrifuge that continuously separates the biomass from the solvent with the THC oil absorbed in it.
A horizontal decanter centrifuge exerts over 3,000 times the gravity force to separate the solvent's depleted cannabis cuttings. This flow-through centrifuge can recover over 95% solvent from the plant matter.
For more details, please read our article on the technical comparison between ethanol extraction centrifuges widely used in this industry.
For the large capacity decanter centrifuge shown above.
|Rated Capacity||170 Gallons/Minute|
|Cannabis Biomass Separation Capacity||80 GPM @ 3:1 Ethanol to Cuttings Ratio|
|Total Mass Flow-Rate||20,000 Lbs/Hour|
|Cannabis Processing Capacity||~ 5,000 Lbs/Hour|
|Ethanol Recovery||Up to 95% by Weight|
|Centrifuge Construction Material||Food-Grade, 316L Stainless Steel Wetted Parts|
|Motor Power||20 HP 460V 3-Phase Motor|
If you have simple, routine questions: We have condensed our 40+ years of disc-stack centrifuge experience into 101 Frequently Asked Questions about Disc Stack Centrifuges!
Decanter & Disc-Stack Centrifuges offer several benefits over basket (washing machine) style centrifuges and downstream filtration of the separated ethanol. Some of these benefits are:
Decanter centrifuges separate the cannabis biomass continuously from the ethanol cannabis biomass slurry. The continuous processing allows this centrifuge to process large volumes of plant matter in a short time.
Conventional basket centrifuges (washing machine type) exert around 1,000 Gs of centrifugal force. Their rotational speed is limited by the basket design that inherently causes balance issues at higher speeds.
A decanter centrifuge is an industrial centrifuge with a flow-through design that does not have this limitation and can therefore exert a much higher centrifugal force over 3,000 Gs.
Industrial centrifuges exert higher centrifugal force and have specific design features that allow them to extract most of the ethanol from the slurry. The separated biomass from a decanter centrifuge can be as low as 5% ethanol and almost dry cannabis biomass.
In addition, the dryness level of the biomass is easily adjustable by mechanical adjustment of the centrifuge. The tradeoff to drier biomass is murkier ethanol that carries more microparticles of the plant matter.
Decanter centrifuges are continuous process separators that do not require stoppage and manual labor to extract the biomass bags. These centrifuges are practically self-regulated and operate for long periods without operator intervention. This feature saves on the labor requirement related to basket-type centrifuges.
Also, the flow-through design does not require biomass carrier bags which is an additional cost of basket-type centrifuges.
Basket-type centrifuges require the operator to manually extract the spent biomass bag from the centrifuge basket. This action exposes the operator and facility ethanol and potential ethanol spills. Decanter centrifuges on the other hand require no manual intervention and are totally enclosed, flow-through systems. This design feature eliminates the potential for ethanol exposure and spills.
Though a decanter centrifuge is efficient at separating the cannabis plant matter from the adsorbent, it does not remove all the suspended particles.
A disc-stack type centrifuge subjects the un-clear fluid to very high centrifugal forces, separating the fine suspended particles.
A clarifying centrifuge separates the THC-carrying solvent from the cannabis plant matter, waxes and lipids carried over from the biomass separation process.
This centrifuge is typically a food-grade centrifuge that produces up to 10,000 times the force of gravity sufficient to remove organic particles as small as half a micron.
Though a high-speed, disc-stack type Alfa Laval centrifuge cannot process fluids below 32 F, the high g-force in this centrifuge removes up to 80% of unwanted wax, lipid, and chlorophyll from the solvent at 32~35 F.
This reduction of waxes, lipids, etc. has many benefits for downstream processing equipment. Primarily, it reduces the filtration needed after the winterization of the solvent.
As a further step, adding and mixing de-ionized water to the hydrocarbon solvent with THC extract dissolves the acidic-based cannabinoids in the water.
A liquid/liquid centrifuge (two-phase) separates the neutral cannabinoid carrying solvent from the water with acidic cannabinoids.
Evaporation of these carrier fluids (solvent and water) independently results in pure THC with acidic and neutral cannabinoids.
The Alfa Laval, High-Speed, Food-Grade centrifuge shown here is ideal for clarifying solvent with absorbed THC. Clarification is a 2-phase separation process to separate suspended solids from the liquid centrate.
In the cannabis THC application, the ideal processing temperature is just above the water’s freezing point (32 F). A considerable portion of the dissolved waxes and lipids are in solid or gelatinous form at this temperature.
The sufficient g-force in the disc-stack centrifuge bowl separates these solids from the solvent, thereby clarifying it for winterization.
Hydrocarbon solvents and ethanol are both flammable fluids. Therefore these centrifuges have to be carefully designed for safe operation in hazardous environments.
All the electrical components need to be certified for the designated location and should be explosion-proof centrifuge or certified for hazardous areas.