Optimize Your Cannabinoid Production with Pope’s Distillation Processing Services

If you’re considering adding distillation to your cannabinoid production or require help in distillation process improvement, reach out to Pope.  In addition to our well-known wiped-film molecular distillation equipment product lines, Pope runs a very active toll distillation services department.

The tolling department includes a range of toll production stills with throughputs up to 230 kg/hr, pilot plant process development equipment and lab-scale feasibility testing stills. Some of the many industries served include foods, flavors, fragrances, bio-materials, extracts, pharmaceuticals, edible and essential oils, cosmetics silicones, lubricants and polyglycerides.

Pope has many decades of experience in wiped-film operation and has harnessed that knowledge to assist our customers in developing, optimizing and commercializing their distillation processes.  We’ve been running numerous trials and piloting of a variety of different cannabinoids with customers’ feedlots for several years.  Our trials and piloting help determine what improvement in purity, yield, color and clarity is possible through distillation.  Pope operates a 2” lab wiped-film unit to conduct trials for our customers and we are capable of following distillation results by Gas Chromatography (GC).  Once your material has undergone trials, we can help suggest opportunities for improvement based upon past experience.

In addition to lab trials, Pope has extensive experience in process development and scaling studies in pilot scale and in performing toll processing for customers who would prefer to outsource to Pope to distill their cannabinoid feed rather than purchasing and running their own equipment.  (This is also a great opportunity for start-ups who want to begin producing their product before they build and run their own lab.) Pope is licensed by the FDA in food GMP and is also kosher and halal certified.  We have a Hemp Processing License with the state of Wisconsin and are able to trial any cannabinoid feed that has a Fit for Commerce Certificate.

Want to know more? Please contact us to discuss your testing and tolling needs.

Using a Mass Balance to Evaluate Your CBD Distillation Process

If the average person was asked to do a mass balance on a system, they might not quite understand what is required. However, for chemical engineers and industrial process chemists this is something learned quite early in their curriculum. While it is a tool often used by chemical engineers, there is no reason why it should not be part of any processor’s toolbox.

For processes involving chemical reactions, the mass balance is written out as:

INPUT + GENERATION = OUTPUT + ACCUMULATION + CONSUMPTION

However, when you are just using separation equipment (such as a wiped-film molecular still for distillation), the equation gets simplified to:

INPUT = OUTPUT + ACCUMULATION

Then, by defining the boundaries of a system, it becomes possible to check where your material is going which can allow you to make better decisions and optimize your process.

Let’s assume you are running a wiped-film molecular still to create CBD distillate. The INPUT to the still will be the feed material (the crude). The OUTPUT of this separation will be terpenes, residue, and CBD distillate. The ACCUMULATION would be any residual material left in the still. There are other outputs; the ethanol collected in the cold trap and any material that is lost through the vacuum pump, however, to simplify this exercise we will lump these into the accumulation and simply define them all as material loss.

While losses to accumulation are important, wiped film stills do not have miles of process piping, so overall this should not be a major concern on the equipment. However, by adding some analytical data to the mass balance much can be learned about your operation.

Example:

Prior to distillation, you have your crude CBD extract analyzed and the lab results come back indicating the material is 65% CBD by mass. You load the feed flask on your system with 2,000 grams of the material. You perform your first distillation and remove 160 grams of terpenes. On your second pass you get 1,155 grams of distillate and 635 grams of residue. When the lab results on your distillate come back, they show 90% CBD by mass. This seems good, but a mass balance will allow you to best review this.

For a Very Simple Mass Balance, You Have:

m_crude = m_terpenes + m_distillate + m_residue + m_loss  (1)

Where:

m_crude = mass of crude

m_terpenes = mass of terpenes collected

m_distillate = mass of distillate collected

m_residue = mass of residue collected

m_loss = material lost (to accumulate, transfer, etc.)

This yields 50 grams of material that is considered lost. Which could either be escaped ethanol or material that sticks as residual in the system (a common occurrence with high viscosity fluids).

Since there is not a large amount of material that was lost, it is now time to look at the amount of CBD you have recovered, also known as your yield. First, you must determine how much CBD is present to start, using equation (2):

m_CBD-C = m_crude * C_CBD-C (2)

Where:

m_CBD-C  = mass of CBD in crude

m_crude = mass of crude

C_CBD-C = _CBD Concentration in crude (mass %)

This equation shows that 1,300 grams of CBD are present in your crude. A similar equation can be used to determine the amount of CBD in your distillate:

m_CBD-D = m_distillate * C_CBD-D  (3)

Where:

m_CBD-D = mass of CBD in distillate

C_CBD-D = _CBD Concentration in distillate (mass %)

Leading to a total of 1,039.5 grams of CBD in your distillate. To calculate the yield of your process you then use Equation 4:

% Yield = m_CBD-D ÷ m_CBD-C  (4)

The percent yield from this distillation is approximately 80%, which would be considered quite sufficient. By further calculation, you can also estimate the amount of CBD that remains in your residue. We will assume that the 50 grams of lost material were at 65% CBD content, like the crude, meaning that 32.5 g of CBD where “lost”. By Equations 5 and 6, you can assume your remaining residue contains 228 grams of CBD or is 36% CBD (mass %):

m_CBD-R = m_CBD-C – m_CBD-D – m_CBD-L  (5)

Where:

m_CBD-R = mass of CBD in residue

m_CBD-L = mass of CBD lost

C_CBD–R = m_CBD-R ÷ m_residue (6)

Where:

C_CBD–R = CBD concentration in residue (mass %)

A great amount of processing in the cannabis industry is performed without much attention to mass balancing and utilizing before/after analyses between process steps.  In many of these cases, the company will get by, obtaining adequate purities and (often unknown) yields.  A somewhat careful operator will often be able to “get the job done”.  However, consistent utilization of the principles of mass balancing, together with obtaining and studying analyses of every batch and run will allow an OK  operator to become an excellent operator.  This person will be able to plan parameters as well as strategies for each run, resulting in optimal purity and yield, leading to lower costs, better product quality, at better pricing, all eventually leading to greater profit for their company than their competitors.

Post-Extraction Cannabinoid Decarboxylation and Its Relationship To Solvent Removal

Introduction to Cannabinoid Decarboxylation

During the course of post-extraction cannabinoid processing, one of the steps normally (though not always) carried out is the conversion of the non-active acid form of the cannabinoid(s) to the active form, prior to final product completion. This is accomplished utilizing a chemical reaction named decarboxylation, (“decarbing” for short). The reaction can be performed at a choice of two different stages in the processing sequence; either with the biomass prior to extraction or else with the liquid form after extraction. In either case, the reaction is driven by heating to increased temperatures (normally between 110° and 150°C) for a specified amount of time (normally between 0.5 and 3 hours), though some operators use more extreme parameters. The reasons for choosing between the pre-extraction and post-extraction methods and the specific parameters used are various and depend on the processor’s feedstock and product goals. Post-extraction decarbing is more common and is the method covered here.

The Reaction & Efficiency

The reaction takes place at a position on the cannabinoid molecule containing a carboxyl group (-COOH). Heat induces substituting the carboxy group by the single hydrogen atom (-H). In the process, the carbon and the two oxygen atoms break away from the cannabinoid as carbon dioxide (CO2) in gas form. For the case of post-extraction decarbing, one of the most efficient known methods is to have a batch of liquid extract contained within a stainless steel reaction vessel which is heated under vacuum conditions and rapidly stirred.

The purpose of agitation is three-fold:

• Agitation helps transfer and distribute the heat required for reaction rapidly, from the vessel walls to the liquid.
• Agitation enables the released CO₂ to better dissipate out of the liquid and into the vapor space, which is under vacuum, helping the reaction to “go to the right” and be conducted efficiently.
• Agitation makes other gases and evaporating solvents efficiently escape from the liquid to the upper space for removal from the vessel.

CO₂ and Ethanol Dissipation

In the majority of cases, the non-active extract will also contain some amount of solvent ethanol, usually as a result of either solvent extraction and/or winterization with chilled ethanol and filtering for wax elimination. After those steps, the bulk removal of the ethanol will have been carried out typically with rotary evaporators for smaller scale or with falling film evaporators in larger-scale operations. However, in many cases, the ethanol is not sufficiently removed to the levels achieved with more careful processing. Often, a decision is made to remove the remainder during the decarbing process since it will conveniently be under raised temperature and vacuum. Thus, the decarbing apparatus serves double duty as a reactor and as an evaporator, discharging both CO2 and ethanol.  However, it is possible, and fairly common, to leave “too much” ethanol in the extract prior to decarbing, resulting in lingering ethanol in the extract, even with a successful decarbing cannabinoid conversion. This occurs due to weak hydrogen bonding of alcohols to organic compounds such as cannabinoids, effectively increasing the alcohol’s boiling point. Too much ethanol remaining in the distillation feed batch can impact the effectiveness of terpenes removal in the 1st distillation pass, with a spillover effect impacting the cannabinoid distillation in the 2nd pass, resulting in a product of lesser quality and yield.

A Turnkey Approach

Pope Scientific provides decarboxylation reaction equipment and complete turnkey systems designed for optimal processing of any required size range to the cannabinoid industry. A complete system includes a jacketed 316L stainless steel reaction vessel with ASME vacuum and pressure rating and food or pharma grade finish, a matching agitator, a heating circulator, condenser, dry running vacuum pump, and instrumentation. Controls can range from simple manual type to automated PLC stations with advanced data handling, depending on the customer’s budget and preferences. All parameters and sequences can be preprogrammed, including an increasing vacuum level during the process, reaching better than 0.5 torr near the end for better subsequent distillation processing. Options include portability and XP Div. 1 or 2 ratings. For increased convenience, the decarbing vessel can be made portable to double as a feed vessel for a Pope Wiped-film Molecular Still.

Optimizing Evaporation Beforehand

It is mentioned above that rotary evaporators and falling film evaporators often do not completely remove ethanol to ideal levels, (<0.1%).  Pope can provide guidance for dealing with these problems.  For various reasons, it is not possible to effectively decrease solvent from high levels to very low levels, (e.g., from 80% to 0.1%) in continuous mode evaporators in a single pass. Pope offers multistage evaporation systems incorporating either a falling film evaporator or a wiped film evaporator for the first stage and a smaller wiped film evaporator for the second stage. This equipment is available in fully turnkey integrated and automated skid-mounted systems.

Contact Pope today or request a quote to discuss your current or future decarboxylation and evaporation equipment requirements.

Case Study: Specialty Silicones Manufacturer Optimizes Processing & Product Quality with Pope

AB Specialty Silicones is a US Manufacturer and Worldwide Distributor of specialty silicone chemicals. They are well known for their customer focus along with providing very high-quality products, service and technical expertise in silicone materials. AB’s core brand Andisil®, encompasses a broad product catalog serving many industries including personal care, dental & medical, specialty chemical manufacturing, electronic encapsulation, adhesives & sealants, coatings, mold making, gypsum, mineral & fiber treatment, pulp manufacturing, roof coatings and others. One of several factors in common with the highest quality polymers, including silicones, is having a very low amount of residual volatiles.

In the early stages of product development, AB Specialty Silicones reached out to Pope Scientific to explore the best methods for producing low volatile silicone pre-polymers and  polymers. Specifically, AB needed to respond to the demand for volatile-free silicone polymers for encapsulation in the LED industry. This particular application brought unique challenges. Silicones can be heat sensitive, leading to degradation including color change, (prohibited for LED applications). Typical batch mode boiling vessel methods for removal of cyclics and monomers were causing such degradation due to the long residence heating time of many hours.

After Pope spent some time learning about the specifics of the application and its challenges, they collaborated with AB to develop the best method with strategies for optimizing the end product through lab trials and pilot plant process development. By utilizing short-path molecular distillation with Pope’s Wiped-Film Still technology, the potential for final product degradation and discoloration is greatly reduced or eliminated through efficient equipment and design process, high vacuum, and decreasing the heat exposure time to a matter of seconds.

Once the processing techniques were finalized, Pope began production toll processing campaigns of the material in their Saukville, WI facility. Bill Marman, Pope’s Toll Processing Supervisor was essential in aiding AB with process development and support throughout this initial project, as well as with future projects. “The original tolling run produced around 40 drums of the specialty low volatile silicone polymers,” says Mac Penman, AB Specialty Silicones’ General Manager.

In 2009, with in-depth collaboration, engineering and processing experience, Pope built AB a 9” Wiped-Film Distillation system to run in-house at their Waukegan, IL facility. Pope helped AB commission the system and was there throughout the installation, performing final equipment testing, process startup and training. They were able to duplicate the processing in-house that they previously had to contract out. “There has always been an open dialogue with Pope. From pricing, to engineering and sales, we’ve gotten great support. We have a great relationship,” says Penman. The new equipment provided AB the ability to increase production of specialty chemicals, often times with complex distillation requirements, for their customers.

Processing has been further optimized through enhancements such as additional control instrumentation and degassing componentry. In 2019, AB added a new Pope 12” Wiped-Film Distillation system to their facility. “The new equipment triples our capacity for producing low volatility materials. Production of high solids, low residual materials are important to meet the growing needs for high purity silicones in specialty electronic applications,” AB Specialty Silicones noted. In 2023, AB expanded again with a 20″ 2-stage Pope Wiped-film molecular still.  All of the product lines AB manufactures – vinyl, hydride, phenyl, and fluoro-functional silicones can be processed in the new equipment. Overall, through their partnership with Pope Scientific – including process expertise, toll processing, and equipment, AB has achieved the competitive advantage in producing high value materials and increased production capabilities.

Download a PDF of the Case Study