Cannabis & Hemp Degas / Decarb
Degassing cannabis removes trace amounts of solvents and volatile compounds from the cannabis oil prior to distillation, or before cannabis oil is sent to market.
Degassing & Decarboxylation
To properly prepare crude oil for further refinement (such as distillation), a degassing procedure should be performed. The terms degassing, devolatizing, or even decarboxylation, are often used to describe this procedure. Although these terms are interchangeable to a degree, they actually mean very different things which can make this a confusing subject when you’re trying to learn the steps of processing cannabis/hemp crude oil. The goal of this article is to help you understand the difference between these terms and be able to use them to purchase the right equipment for your processing facility.
A note on Degassing Cannabis:
Decarboxylation and devolatilization can be achieved by using the same equipment and process. This process is often referred to as degassing. In the following paragraphs, we will go into detail about the chemical process of decarboxylation, the physical process of devolatilization, and how both of them are achieved through degassing.
Decarboxylation is a type of chemical reaction that releases carbon dioxide from non-activated acidic compounds. This reaction causes those non-activated compounds to become activated. Activation enhances the desired physical and psychoactive effects of these compounds. Because of this, it is often a vital step in cannabis/hemp processing.
Decarboxylation can be performed on plant material as well as on crude oil. Most often, this is where the term originates. When performing decarboxylation on plant material, heat is applied. The heat causes a chemical reaction and activates those compounds within the plant material.
This should not be confused with decarboxylation as it relates to degassing or devolatilization. Those can only be achieved when using crude oil that has undergone previous processing steps.
One of those steps would be winterization and solvent recovery, which often leaves behind 1 to 10% of the solvent that must be removed. To do this, the crude oil is heated with a variety of equipment, which will be discussed further below.
Heating the crude oil to a high temperature will decarboxylate the compounds within the oil, thereby activating them. But, chances are most of those compounds have already been activated in previous processing steps. For example, if the plant material was activated using heat, the crude oil coming from that plant would also be activated. Removing that 1 to 10% of solvent, using heat, can also be called devolatilization.
As discussed above, the process of devolatilizing crude oil will also decarboxylate the target compounds in the crude oil. But, most often decarboxylation is not the goal of the “degassing” process. Devolatilization is much more important and must be done before distilling the crude oil.
To achieve a devolatilized crude oil, heat is applied. This heat forces the evaporation of the small amount of solvent and other light volatiles such as terpenes and water, that remain in the crude oil. These volatiles can have a negative effect on both the efficiency of distillation as well as the performance of the equipment used in the process. For this reason, devolatilizing the crude oil (using a degassing procedure) must be performed prior to distillation.
Non devolatilized crude oil takes much longer to distill because those lighter, volatile compounds must be distilled out prior to distilling the targeted higher- boiling-point compounds. These volatiles not only increase the overall time of the cannabis/hemp crude oil distillation, but they can cause performance issues with the equipment in the process.
Most distillation equipment is not designed to handle high amounts of volatiles, these volatiles can shorten the lifespan as well as increase the maintenance intervals of the equipment. Due to the overall efficiency loss, you can see why it is imperative to devolatilize crude oil prior to distillation.
To properly devolatilize the crude oil, a degassing procedure is performed. With a hot plate for small-scale production or a reactor system for larger-scale production, the crude oil is heated to approx. 100-140°C for 1 to 2 hours or until the oil is fully devolatilized.
It is actually quite simple to perform this step, but it can require specific equipment depending on the needed capacity.
To perform a smaller-scale degassing procedure (1 to 10 liters), place a beaker ¼ to ⅓ full of crude oil after it has been fully winterized, on a hot plate magnetic stirrer. The stirrer can be turned to a slow speed to help agitate the crude oil and provide further evaporation. The crude oil should be heated slowly up to 140°C for 1 hour or until bubbling or foaming has subsided.
Note: When performing such a procedure, a fume hood should be utilized to prevent solvent vapors from escaping into your workspace.
For larger-scale production (10+ liters), a jacketed reactor system is used. The reactor system will include temperature control to allow for proper heating as well as a vacuum system and agitator to further speed up the evaporation rate. Solvent and volatile vapors should be properly condensed in a separate area, such as a cold trap, to minimize vapors from escaping into your workspace.
Degassing, devolatilization, and decarboxylation are all terms that are used interchangeably but mean very different things. What remains the same is that all three can be achieved using the same type of processing equipment. Please contact us for questions regarding degassing, devolatizing, or decarboxylation in your process. We provide solutions that can achieve all three at varying degrees of scale.