Take a Guided Tour of CO2 Extraction: Part 1

From the machinery and components through to solvent recovery, learn how CO2 extraction is made possible!

Part 1 - get familiar with the systems and equipment involved, from pump technology to phase management.

Carbon dioxide (CO2) makes an excellent extraction solvent for botanical oils. CO2 is a unique solvent as it retains its solvency power as either a (subcritical) liquid or as a supercritical fluid depending on the respective temperature and pressure. By changing the pressure and temperature of CO2, its solubility and selectivity for a specific compound of interest can be changed to optimize an extraction.

This three-part series will provide a guided tour through the process of extraction using CO2 as the extraction solvent. Various aspects of the extraction system will be covered ranging from the machinery and components, the different parameters that can be used, to the interwoven principles of extraction (see Figure 1 for an overview). The first part will provide a mechanical focus on the early stages of the process, particularly on storage of the solvent and the distribution of the solvent via a dual acting positive displacement pump. Part two will examine what occurs during the extraction process in the extraction chamber, solvent power and the associated solubility. Finally, part three will cover the separation of the solutes from the solvent stream and solvent recovery.

The Vitalis Difference - Figure 1 Pages - Block Diagram-01

1. STORAGE

The extraction process begins with the CO2 accumulator. This is the reservoir that supplies the system with solvent during operation. CO2 can be stored here as either a low-pressure gas, a high-pressure gas or a liquid.

The Vitalis Difference - Phase Management - Final_corrected

2. DISTRIBUTION

The pump is the next stage of the process. The job of the pump is to deliver CO2 to the system at a selected pressure. The two most common pumps that are used in the extraction industry today are dual acting positive displacement pumps and diaphragm pumps.

DUAL ACTING POSITIVE ACTING DISPLACEMENT PUMPS

Dual acting positive displacement pumps have the ability to deliver an uninterrupted flow of solvent into the extraction system. In turn, the pump’s hydraulic cylinder applies force to two oppositely directed pistons. Liquid enters the available space ahead of one piston, as force is applied to the other to deliver a volume of the solvent. At the completion of this stroke, force is then applied to the opposite piston, now primed with a volume of solvent ready for delivery to the next section of the machine. Hence, dual acting positive displacement pumps eliminate the interruption in solvent output (by eliminating the down stroke). Figure 2 shows the recharge and output operation of the dual acting positive displacement pump. Due to their efficiency and continuous solvent delivery, and the fact that their design is very robust, they are the favored option for use in extraction equipment.

Figure 2

DIAPHRAGM PUMPS

Briefly, solvent only enters diaphragm pumps on their down stroke and is then delivered on their output stroke (Figure 3). Despite numerous variations on their designs, solvent delivery results from these pulses; thus, the system will experience an interruption in the flow of solvent at each down stroke as the pump is primed with a new volume of solvent for delivery. Furthermore, diaphragm pumps generally have smaller displacements (being that the pump strokes provide a lesser fluctuation in internal volume) and operate at higher frequencies (more cycles for the life of the operation) which results in increased wear and system pulsation. This style of pump is also known to be less robust, making it less reliable, which leads to potential increased downtime for maintenance and component failure.

Figure 3

Regardless of what pump is chosen, as the CO2 reaches the pump, it must either be as high-pressure gas or in a liquid state. As previously mentioned, only liquid and supercritical phases of CO2 have adequate solvent power to be used in extraction. It is important to note that if a high-pressure gas is delivered to the chamber, enough additional pressure must be built up within to produce a liquid or supercritical fluid. If the solvent is pumped as a liquid, no change of phase is required. However, an operator may wish to adjust the fluid temperature which would include potential selection of the supercritical phase, before the solvent reaches the extraction chamber.

PHASE AND EFFICIENCY

Importantly, the phase of the solvent as it is acted upon by a system’s solvent-delivery pump can affect the extraction machinery’s mechanical efficiency. Liquids are effectively non-compressible, meaning the force applied by the pump is used to efficiently deliver solvent to the system. Conversely, more work is required when applied to a volume of gas and this will be given off as thermal energy as the gas is compressed. This means, that when acting on a volume of gas, an amount of the output stroke’s energy is then converted to heat.

Delivering the solvent as a liquid incorporates further efficiency as the density (being the number of particles per unit volume) of gases, even under high pressure, is much lower than that of liquids. This means that two identical pumps, one primed with a volume of gaseous CO2, the other with an identical volume of liquid CO2, do not contain the same amount of solvent. The pump filled with the liquid CO2 contains more solvent molecules than the pump filled with gaseous CO2. This results in fewer pump strokes that are required to deliver a given amount of solvent when it is pumped as a liquid.

3. PHASE MANAGEMENT

Phase management is an optional stage during the extraction process. Temperature adjustments including those where a phase change is induced, can be made using a phase management system. To adjust the solvent temperature, the flow is directed through one or more coiled or folded solvent flow paths within heat-exchange bath(s) or vessel(s). These flow paths are designed to maximize the surface area and can be used to either increase or decrease solvent temperatures through the flow path piping.

From here CO2, either as a subcritical liquid or supercritical fluid, goes into the extraction chamber where the extraction process takes place, before following on to the separation stages. These stages will be covered in the ensuing two parts of this guided tour of a CO2 extraction system.

The Vitalis Difference - Phase Management_v2

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Extraction Fact vs. Extraction Fiction

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CLAIMS OF TIME & RECOVERY

Extraction as an industry is growing fast, and there are a number of companies vying for market share and consumer attention. In the CO2 space alone, there are dozens of companies supplying equipment to the industry. In this space, it's natural to see organizations trying a number of different tactics to get ahead.

Unfortunately, in the course of competitive business, statements can be made that are inaccurate and/or false. One typical myth that has had its time in the spotlight is the subject of yields. This topic can arise when people try to make simple comparisons between different types of equipment, and it is used as a measure of efficiency. However, as has been covered numerous times (check out this article), the subject of yields can be confusing and even misleading.

There have been numerous instances where the question "what is the yield on this machine?" is followed up with a simple numerical response like, "30%". Without even questioning the starting material going into the system, this can be misleading. If one were to use starting material that is 5% cannabinoids into a system, getting 30% yield would mean that most of the output would be non-cannabinoid material.

While the topic of yields and the confusion surrounding it has been discussed for years, a new subject of interest has come to light - percent extraction efficiency, also referred to as recovery percentage . The percent extraction efficiency is a number calculated by measuring the difference in cannabinoid mass between the feedstock and the post-extraction raffinate. As a simplistic example, if 100g of a specific compound existed in a specific volume of plant material, and the extraction output was measured to have 97g, the percent extraction efficiency would be 97%.

Unfortunately, while this topic has started to gain traction, so too have some of the myths surrounding the process. For example, some are reporting that they're hearing statements about the recovery percentage of a particular system within a specific period of time. For arguments sake, let's use the example of a 95% recovery in a run-time of 2 hours. These results are fantastic, but are they even possible? Keep reading to find out.

THE SCIENCE OF EXTRACTION

CO2 extraction is a process that has as part of its foundation a few key scientific principles. The key factors in an extraction are temperature, pressure, time, and flowrate. Under a set of parameters (temperature and pressure) during a run of a specific duration (time) and based on the overall volume of solvent passing through the substrate (flowrate), an extraction will produce a quantity of crude oil.

For different compounds within the biomass, different temperature and pressure settings can increase or decrease their solubility within the solvent. As well, the more time the extraction is given to run, the more of that particular compound can be extracted (this article talks about the "declining curve" of recovery that is typically noticed). Finally, the amount of solvent that is flowing through the chamber can also increase the overall efficiency of the extraction.

None of these factors are magical. Rather, they are scientific principles upon which extraction is based. The end result of the extraction is similarly based on the science. Given a specific set of parameters, the laws of physics, the phenomenon of mass transfer and solubility, an extraction occurs.

THE EXTRACTION CURVE

This image represents the extraction curve, or better put, gives a graphical look at the amount of cannabinoids that can be pulled from the plant material over time. The familiar "declining curve" shows that in the first part of the extraction, the majority of cannabinoids are recovered. As the solvent continues to penetrate the biomass, components that are further from the surface of the material take longer to recover. Over the course of the run, the remaining desirables are pulled.

Given the laws of physics and the physical properties of solvent and biomass, this shows what happens when appropriate temperature and pressure parameters are set when targeting cannabinoids. These parameters are chosen as they are the most favorable for extraction of target compounds with as little co-extraction of non-desirable components like fats and waxes.

THE UN-TRUTH

Technically, 95% recovery in 2 hours is possible. This can be accomplished by drastically increasing temperature and pressure settings during the extraction. Unfortunately, the by-product of such a process is the complete extraction of both desirable and undesirable compounds. This leads to a situation where post-processing requires greater amounts of time, energy, equipment and resources. In this case, maintaining these numbers indefinitely is neither profitable nor sustainable.

When evaluating claims that are made across the industry, it is wise to get the actual details behind the statement. If a claim like our example is heard, then the discussion should focus on the how - how is it possible to reach those numbers, and what are the downsides that also result? Similarly, hearing wild claims about the yield of a particular extraction system should be met with queries regarding the biomass. What are the percentages of desirable compounds in that plant material, and how does that compare to the claim (remember, 30% yield from a 20% feedstock is nothing short of magical)?

As the industry gains momentum, we can anticipate more outrageous and fantastic claims. As in most situations, regardless of industry or transaction, critical thinking pays off. Like the saying goes, “if it sounds too good to be true, it probably is.” While some “claims” can technically be true, the realities may not be close to the desired outcome. Educate yourself, purchase wisely.

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CO2 Extraction Without Winterization

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Carbon dioxide (CO2) is an excellent choice of solvent for extraction of natural compounds. The technology has been used successfully in commercial applications for over 40 years, including hop extraction, herb and spice extraction, oilseed extraction, and coffee decaffeination. CO2 is non-flammable, non-toxic, cheap, and readily available in large quantities at high purity. The extraction process is carried out at near-ambient temperature preventing damage to heat-sensitive compounds, and small changes in process temperature and/or pressure can result in large changes to solubility.

For these reasons, the cannabis industry has adopted CO2 extraction as an ideal method for cannabis oil processing. Cannabis is an extremely complex plant containing over 550 unique chemicals identified to date, including cannabinoids, terpenes, phenols, flavonoids, fatty acids, pigments, and other miscellaneous compounds. Typically, the cannabinoid and terpene fractions collectively make up approximately 10-30% of the mass of buds. Though the larger residual fraction contains many beneficial compounds, it is the cannabinoid and terpene fraction that the industry is focused on for extraction and purification.

UNDERSTANDING WINTERIZATION

In a typical CO2 extraction, extraction parameters can be tuned to produce crude oil that contains 45-80% cannabinoids and terpenes. The remaining portion will consist of co-extracted components from the feedstock that are either highly soluble in CO2 at the given processing parameters; or, have low solubility but are easily accessible and co-extracted with limited mass transfer resistance. A process called winterization can be employed to remove the co-extracted fraction. In this process, the extracted crude oil is mixed with another solvent and exposed to cold temperature to precipitate some amount of the undesirable co-extracted solids. The solids are then separated from the liquid through a filtration process, yielding what is known in the industry as a “winterized oil.” Depending on the desired outcome of the process, the oil may be further processed or purified or formulated directly into retail products.

Winterization can be a time-consuming process and can be a rate-limiting step in some cannabis processing operations. Because of this, many manufacturers are touting equipment that can eliminate the need for this additional process. However, these claims generally cloud the truth by avoiding discussion of the pros and cons.

Can winterization be minimized or eliminated? The answer is yes, but a better question to ask is should it be? Read on for some tips on reducing winterization in CO2 extraction.

You get what you put in.
In general, extracting feedstock with a high content of desirable constituents will yield an extract with a high content of desirable constituents (provided these constituents are easily extractable). In other words, starting with high-potency, terpene-rich cannabis feedstock will yield a crude extract containing a high cannabinoid and terpene content. Conversely, starting with a low potency low terpene feedstock (i.e. trim or industrial hemp) will yield an extract with a higher content of non-cannabinoid, non-terpene material that will likely require winterization.

Material Preparation.
Reducing particle size will increase the mass of feedstock that can fit into a given volume (increase density) and increase the extraction efficiency by reducing the distance the solvent must travel to reach the center of a particle. However, reducing particle size ruptures plant cells and exposes their interior contents to the solvent. This increases the likelihood of coextraction of undesirables, which require removal using winterization.

Extraction Parameters.
One of the benefits of CO2 extraction is tuneability; solvent power is affected by changes in CO2 temperature and density. Thus, extraction parameters can be tuned to favor the extraction of a compound or groups of compounds with similar chemical properties. For example, Perrotin-Brunel et al (2010) examined the solubility of pure THC in CO2 and found that at extraction pressures lower than 2175 psi, THC solubility decreased with increasing temperature (density-dependent), and at pressures higher than 2175 psi, THC solubility increased with increasing temperature (temperature dependent).

Many cannabis processors choose to use cold (<60 F), low pressure (<1200 psi) liquid CO2, as terpenes are highly miscible under these conditions. Liquid CO2 is very dense, having low selectivity and high solvent power towards high molecular weight compounds. Further, the solubility of major cannabinoids in CO2 at these parameters is low, so more solvent contact is needed and thus, more time is required if cannabinoid extraction is the goal.

Alternative Separation Methods.
There are alternative methods of separation that do not involve traditional winterization techniques. As with many technologies used in the cannabis industry, many have been adopted from other industries. Decantation, for example, can be used to separate immiscible liquids with different densities. In the food industry, a centrifuge is used to separate cream from skimmed milk. Another example would include nanofiltration, which can filter fats from oil without the need to first freeze and precipitate the fats as solids.

Not all products require winterization.
Perhaps the goal of the manufacturer is to make a “broad-spectrum” oil that contains all the components, plant fats and waxes included, originally extracted from the plant material. Such an extract would most closely resemble the chemical makeup of the original plant material. Raw crude extract can either be packaged as-is or diluted with a carrier oil to achieve a desired cannabinoid concentration. Typical products would include capsules, tinctures, and syringes.

Extraction without winterization is possible, but its application to business processes is reliant on the feedstock, preparation, and parameters. Alternative extraction methods provide some options, while product options provide more. However, in the typical day-to-day world of CO2 extraction, companies need to be sure that their end goals are compatible with the requirements and outcomes of a winterization-free process. If somebody tells you that winterization isn’t required, be sure you are clear on the intended results.

If you need more information on extraction, with or without winterization, the Vitalis science team is able to help. Work with a team of experts that can back up their claims with science and data; a team that consistently assists customers in understanding the nuances of extraction and processing.

References:
Perrotin-Brunel, H. et al. 2010. Solubility of Δ9-tetrahydrocannabinol in supercritical carbon dioxide. The Journal of Supercritical Fluids 52: 6-10.

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When Outfitting Your Lab, Choose CO2. Here’s Why:

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THE DIFFERENCES IN CANNABIS EXTRACTION TECHNOLOGIES

The cannabis industry today is comprised of three main extraction technologies; carbon dioxide (CO2), ethanol and hydrocarbons. Although these extraction methods are different, they all try to achieve the same objective of extracting valuable compounds from cannabis plant material. The main compounds targeted by these extraction systems are cannabinoids and terpenes, but each extraction method has its own respective advantages and disadvantages when extracting these compounds. Not only are the differences solely in how the compounds are extracted, but also extend to extraction safety, environmental impacts and costs. Having an understanding of these extraction methods is important when determining what cannabis extraction method to use. The characteristics that would be important for someone looking to purchase cannabis extraction equipment are discussed below for the three extraction methods mentioned.

CO2

CO2 in its liquid form can be used as an extraction solvent if its temperature and pressure are within the liquid phase range, or as a supercritical fluid if its temperature and pressure are above both 87.98 F and 1071 psi. It is an outstanding solvent for volatile compounds such as terpenes and, as a supercritical fluid, is good for cannabinoid extraction. The final separation of the solvent from the extract is achieved by a density drop that allows CO2 to evaporate from liquid or supercritical fluid to gas. The liquid cannabis oil that is left behind is free of any residual solvents.

Table 1: CO2 extraction system characteristics

Criteria CO2
Scalability Low to high
Infrastructure Required No significant infrastructure required
System Cost Medium to high
Product Options High; tuneability and terpene preservation allows for diverse product offering
Extraction Run Times Medium - long
Energy Usage Low to medium
Solvent Cost Very low
Tuneability Yes
Terpene Preservation Yes
Post Processing Winterization may or may not be required, depending on feedstock input and desired product formulation
Residual solvent in crude extract No residual solvent in extract
Pre-cool solvent No
Feedstock waste No residual solvent, general waste
Solvent Generally Recognized as Safe (GRAS) Yes
Safety High pressure
Solvent disposal Vent to atmosphere

The tuneability of CO2 and its ability to switch between a liquid and a supercritical fluid is a tremendous advantage for this process, and allows for a more diverse range of product offerings. Depending on the chosen parameters, extraction of undesirable compounds such as chlorophyll and lipids can be reduced, or a terpene pull can be completed using a subcritical run. As CO2 can extract at lower temperatures and pressures, subcritical parameters are good for targeting low molecular weight terpenes while leaving other components behind. Typically, with CO2 extraction, a post-processing step of winterization is required to remove undesirable compounds.

Another major advantage of using a CO2 extraction system is the relatively small infrastructure requirements. Unlike ethanol or hydrocarbon extractions that require a Class 1 Division 1 or 2 space, no specialized infrastructure is needed. This represents significant cost savings up front and helps mitigate the expense of the equipment.

CO2 extraction is the leader in safety in terms of residual solvent toxicity as well as environmental impacts relating to solvent disposal. Most extractors will reuse the CO2 or simply vent it to the atmosphere, saving on costly hazardous waste solvent disposal. CO2 is relatively inexpensive to restock, so even when levels need to be topped up, the costs are minimal. This is yet another area in which CO2 proves its affordability in the long run. With the savings on infrastructure, and the long-term costs of maintaining solvent stock, CO2 ends up being a more cost-effective process than the alternatives.

Ethanol

Ethanol extraction is best performed at temperatures below -40 °C, where the co-extraction of undesirables is minimized. However, cooling ethanol to these temperatures can require significant amounts of energy and time. Ethanol is a polar molecular, and this can create issues as it will readily mix with water and dissolve water soluble molecules such as chlorophyll. However, at temperatures below 40 °C this phenomenon is limited. During the extraction process, ethanol is passed over the cannabis material to dissolve the active compounds in the plant.

Table 2: Ethanol extraction systems characteristics

Criteria Ethanol
Scalability Low to medium
Infrastructure Required C1D2 or C1D1 space
System Cost Low to medium
Product Options Low to medium; poor terpene solubility means smaller product offering
Extraction Run Times Short to long, depending on solvent cooling duration
Energy Usage Low to high, depending on solvent cooling
Solvent Cost Medium to high
Tuneability No
Terpene Preservation No
Post Processing Winterization may or may not be required, depending on solvent cooling
Residual solvent in crude extract Solvent recovery required
Pre-cool solvent Below -40°C to minimize co-extraction of undesirables
Feedstock waste Residual solvent, hazardous waste
Solvent Generally Recognized as Safe (GRAS) Yes
Safety Flammable
Solvent disposal Hazardous waste

A major advantage of ethanol extraction systems is that they have a low cost of entry. However, due to ethanol’s flammability, infrastructure to support such an extraction system is more costly due to the requirements for hazardous locations (C1D1 or C1D2 – which means there is an ignitable concentration of flammable gas or vapour that has to be contained).

Terpenes have low solubility in ethanol which results in an oil that can lack flavour and aroma, and a reduced product offering for the extract. What ethanol excels at is cannabinoid extraction and it tends to have shorter extraction run times which is highly beneficial for throughput. The tuneability of the ethanol extraction method is very low and is primarily used to target cannabinoids. Ethanol, like CO2, is also generally recognized as safe (GRAS) for consumption by the FDA. But an important consideration is solvent recovery as residual solvent in the product could harm end users. Furthermore, ethanol waste is classified as hazardous, which in turn requires special handling and disposal.

Butane

Hydrocarbon extraction equipment typically uses butane, propane, or hexane as the extraction solvent (although most commonly butane). Cold butane is washed over the cannabis material, which slowly dissolves the cannabinoids and terpenes. As it is non-polar, it binds to the more fat-soluble components of the plant (cannabinoids, terpenes and lipids) and less so to chlorophyll and other plant metabolites. As it has a low boiling point (-0.5°C/31.3°F), very few temperature sensitive terpenes are lost when boiling off the residual solvent from the concentrate solution.

Table 3: Hydrocarbon extraction systems characteristics

Criteria Hydrocarbon
Scalability Low to medium
Infrastructure Required C1D1 space
System Cost Low to medium
Product Options Medium to high; terpene preservation and cold processing allows for diverse product offering
Extraction Run Times Medium
Energy Usage Low
Solvent Cost Low to medium
Tuneability No
Terpene Preservation Yes
Post Processing Winterization may or may not be required and desired product
Residual solvent in crude extract Solvent recovery required
Pre-cool solvent No
Feedstock waste Residual solvent, hazardous waste
Solvent Generally Recognized as Safe (GRAS) Yes (for butane)
Safety Pressurized and explosive
Solvent disposal Hazardous waste

Butane extraction is excellent for the extraction of cannabinoids and terpenes under the same conditions, and when done properly can produce a terpene-rich end product that closely resembles the starting plant material. This process tends to produce great tasting concentrates like shadder, budder, sauce and more.

However, butane and other hydrocarbons are highly flammable and volatile, which means there are strict regulations that surround butane extraction systems. Again, like ethanol extraction, a hazardous location space is required, and a solvent recovery step is needed following extraction. The spent butane is also classed as hazardous waste and appropriate environmental disposal is required.

While ethanol and butane extraction systems have their place in cannabis extraction, CO2 has proven itself to be one of the most adaptive and safe cannabis extraction methods. The CO2 extraction process is well known for its low up-front infrastructure cost, safe solvent use, scalability, and tunability. These factors, along with its long-term environmental sustainability, make CO2 an excellent choice for cannabis extraction.

High-Volume Extraction

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WHY YOUR CHOICE IS CO2

With harvest imminent, many businesses are examining extraction systems that have the capacity to process large volumes of biomass. When considering options to deal with these quantities, ethanol extraction tends to be top-of-mind. Ethanol is well known for its ability to perform extractions with short run-times, meaning more batches per day and more volume processed. However, with advances in technology and manufacturing practices, extraction using CO2 has become part of the high-volume conversation.

In the past, CO2 hasn't been a viable option due to the size of the systems available. Prior to the last two years, most CO2 extraction systems were limited to 40L or less. In those cases, to manage high-volume extraction, processors would require fleets of systems and the people to operate them. This could be inefficient and cost prohibitive.

As the industry has progressed, companies have started to manufacture larger, industrial-scale systems to meet the needs of extractors. Where the Vitalis Q-90 system was once considered massive in CO2 extraction, the R-400 series system has become the focus for many new customers. Working with OEMs like Vitalis, processors are also able to build custom, factory-scale systems to meet their needs. As technology and innovation moves forward, standard production systems with even greater capacity are on the drawing board, reducing the need for multi-unit deployments.

Here are a few more reasons why CO2 should be top-of-list when considering high-volume extraction.

CAPITAL EXPENDITURE VS OPERATING EXPENSE

CO2 extraction equipment has a reputation for being expensive. When looking at the initial capital expenditure, these systems tend to be higher on the cost scale than many other options, and that expense increases as higher capacities are required. Unfortunately, the true affordability of CO2 extraction can be missed if consideration is only given to equipment acquisition cost.

While ethanol extraction equipment can be relatively inexpensive compared to CO2 solutions, the ongoing costs to replenish solvent are substantial. As well as the expense necessary to keep solvent in stock, additional engineering bills - necessary to ensure facilities meet regulations for working with flammable and explosive substances - can drive the overall cost of ethanol extraction into the millions.

For high-volume processing requirements, the cost of solvent increases relative to capacity. The more biomass to be processed, the more solvent required. The cost-per-litre of ethanol is certainly higher than CO2, and this is a standard operating cost that is required for as long as extraction processing is to continue. CO2 equipment can be expensive to obtain, but ethanol is expensive forever.

CO2 is an inexpensive solvent to keep stocked, and extraction facilities typically require little to no specific engineering in order to pass safety inspection. At pennies-per-litre, the operating expense to keep CO2 stocked is far more affordable than ethanol alternatives. Despite the increase in solvent required to process large volumes, the minimal rise in cost is far easier for businesses to handle. When combining both capital expense and operating expense, CO2 is much more attractive from a dollars and cents investment perspective.

GMP

GMP (Good Manufacturing Practice) considerations can also increase the operating expense for ethanol extraction systems. GMP requires that substances that come into contact with the product do not alter the product quality. While the solvent power of ethanol makes it a great choice for extraction, it also makes it extremely difficult to avoid batch-to-batch contamination while re-using ethanol for multiple runs. Even with a wealth of costly post-processing equipment, recovered ethanol will typically contain residuals of the compounds extracted from the previous run. Further, validating ethanol as clean and free of contamination could be a large challenge.

To achieve GMP compliance, ethanol processors may have to replace the solvent for each extraction batch, adding hazardous waste disposal as an additional operating expense. Even in situations where solvent recovery and re-use is possible the operating expense is high. In the case of high-volume extractions, where the solvent would need to be replaced after each run, the costs necessary to meet GMP requirements would be astronomical and unfeasible for many companies.

SELECTIVITY

As well as cost considerations, using CO2 systems for high-volume extraction also provides one significant advantage: selectivity. The tuneability of CO2 as a solvent has made it a popular choice for processors wanting to make a wide variety of products. The ability of CO2 to extract specific target compounds based on the parameters of extraction is one of its most beneficial attributes. Using it for extractions of large quantities of biomass doesn't diminish this ability.

With the investment necessary for high-volume extractions - from cultivation and cost of biomass to equipment and facility purchases - a sudden shift in the market from one type of product to another can spell disaster for processors that can't adapt. With CO2, adapting to market changes can be as straightforward as changing the extraction parameters, and making minor changes to post-processing practices. Even without significant market changes, using CO2 provides the opportunity for processors to make a wider spectrum of end products and ensures overall business stability and longevity.

CO2 MAKES SENSE

Given the advantages CO2 brings to the extraction lab, using it for high-volume extractions makes sense. With the capacity of systems getting larger and larger, the ability to use it as a go-to process is getting more affordable and efficient for processors. As well, new markets in Europe, where GMP is the standard, forcing companies to examine CO2 as an option in order to gain access.

Where ethanol was once the method of choice, examination of the overall cost of operation reveals a process that can create financial challenges and risk to processing companies. Further, the challenge required of ethanol processes to feasibly meet GMP standards can see companies shut out of a burgeoning market entirely. CO2, having recently closed the gap on capacity, and being far more affordable in the long run, has become an attractive option for large volume operations. With the summer harvest season, the time is right to investigate all that CO2 extraction has to offer.

If you’d like more information or solutions to process large volumes of biomass, give our Accounts team a call. With high-capacity extraction systems, and end-to-end ancillary services available, the Vitalis team can help you maximize profits and efficiency in your extraction efforts.

CO2 Extraction and Plant Profile Retention

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With interest increasing into the benefits of plant extracts, many companies are seeking better methods to use for extraction.

Though traditional processes present advantages, the use of harmful solvents can have a drastic effect on the quality of the finished oils. CO2 extraction provides an alternative that allows for excellent retention of valuable plant compounds.

Many target compounds are delicate and can be easily destroyed by heat, whereas CO2 extraction offers a delicate method, allowing companies to produce a broad-spectrum oil that most closely resembles the flavor and aroma profile of the original plant material.

USING SOLVENTS

Plant compounds that are difficult to extract or too fragile for steam distillation can be extracted using a number of solvent based solutions. Solvents are substances that dissolve a given solute.

In this case, the solutes are the compounds within the plant matrix.

Common solvents currently used are:

  • Butane
  • Hexane
  • Methanol
  • Ethanol

Solvents are passed through the chamber and its contents, diffusing through the material and dissolving compounds. If processed incorrectly, several of these solvents can leave behind traces of unwanted chemical residue. Though standards for oils for consumption have become more stringent and require quality testing, there remains a perception among consumers that oils derived from these methods are lower quality or potentially harmful if consumed.

Ethanol is a safer solvent and has many advantages including processing time. However, there are significant disadvantages. Operating costs – given the price of the solvent and the extra infrastructure required to support large volumes of ethanol – can be problematic for many processors. As well, ethanol has poor retention of terpenes, and to avoid co-extraction of chlorophyll, ethanol must be chilled to less than 40 degrees Celsius. This can take a significant amount of energy and time.

This is where CO2 extraction can prove to be a superior solution.

CO2 EXTRACTION

Extraction using carbon dioxide has many advantages, including selectivity. Subcritical CO2 provides a fantastic option for the preservation of delicate terpenes and flavonoids, while supercritical CO2 – having properties of both a liquid and a gas, can be an efficient solvent for the recovery of cannabinoids.

Carbon dioxide is an excellent solvent as a supercritical fluid because:

  • It can have a near liquid density
  • It has low viscosity and diffuses quickly like a gas
  • After depressurizing, it leaves no solvent residue.

Through CO2 extraction, delicate compounds are retained through the process, and a broad-spectrum plant profile can be retained.

MASS TRANSFER & SOLUBILITY

Extracting the compounds of interest from a feedstock’s matrix is most easily accomplished with the assistance of a solvent. Regardless of what starting material is to be loaded into the extraction chamber, success in extraction begins with ensuring the selected solvent and conditions of extraction are a suitable match for the components of interest the operator wishes to target.

Each solute of interest will have a set of ideal solvent conditions for its extraction based on two main areas of characteristics. These are:

  1. the qualities about the compound of interest that can be targeted to help coax it into solution
  2. those that help provide the impetus to favour the compound of interest leaving its position in the plant matrix.

In other words, there are both pull factors and push factors governing the behaviour of solutes which can be capitalized upon to help optimize their mass transfer (that is, their movement) from the plant matrix to the solvent.

Carbon dioxide, a non-polar solvent, has compatible characteristics for the solutes of interest in the cannabis industry. Further, it boasts a very wide range of pressures and temperatures at which it maintains appropriate density to act as a solvent while still providing advantages in diffusivity to increase efficiency of plant matrix penetration. Finally, it also lends itself well to dynamic extractions.

Capitalizing on all these factors for a solvent-solute pair will take into account;

  • A polarity match between the solute and the solvent;
  • Maximizing chemical potential by renewing the volume of solvent in the extraction chamber, that is, ensuring to maximize the natural phenomenon of diffusion from areas of higher solute concentration (the plant matrix), to lower solute concentration (the renewed volume of solvent);
  • Tuning pressure and temperature to:
    • Find the ideal balance between solvent density and diffusivity;
    • Impart enough kinetic energy unto the solute molecules to cause them to want to transition phase to a vapour (that is, to capitalize on their inherent volatility; note that the amount of energy required will be different for each and every compound);
    • Ensure conditions are mild enough to avoid thermal alteration of the solutes.

Other factors of importance that will impact and extraction’s efficiency include;

  • Structure of the plant matrix;
  • Size of the feedstock particles and other pre-processing considerations.

QUALITY EXTRACTS

For an extraction orchestrated by a skilled operator, and carried through to completion, carbon dioxide can provide a representative profile of the original components present in the plant. It also imparts a massive advantage in solvent removal in the primary product as it is collected from the extraction equipment.

At the end of the day, CO2 extraction gives consumers an excellent opportunity to experience a satisfying, broad-spectrum product.

 

Ancillary Selection: Important Decisions For Your Business

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Turnkey is a common phrase in most industries. By definition, it's a complete product or service, ready for immediate use. For many, the "ready for immediate use" is the biggest draw, and in a society that values time and instant gratification, the idea of having a solution ready to go right out of the box is attractive.

But, when moving into more technical areas, “turnkey solution” is just another buzz phrase. In situations with multiple variables and factors, using a cookie-cutter solution can have more cons than pros. As carpenters often say, "measure twice, cut once", and in the case of technical solutions, it is usually wiser to spend time up front to get the right solution, rather than choosing Combo A over Combo B and hoping it fits.

When it comes to ancillary equipment in the extraction industry, this couldn't be more true. From initial grinding to final refinement, there are several different products that could be used, and the combination required for real success isn't likely to be found in a single, pre-packaged solution.

KNOW YOUR PRODUCT

The first question that should be answered when examining ancillary equipment is "what do I want to make". The product decision will have the greatest impact on the type of equipment needed in your processing lab.

Using a CO2 extraction system will result in a crude oil that is generally usable right from the start. Of course, many processors want to refine that oil in order to create other, more marketable products with various concentrations.

Knowing the product you want to create can help guide the ancillary process. The more refinement required, the more equipment will be necessary. As well, understanding exactly where waste can be reduced and where profit is maximized within a particular business can greatly affect what types of equipment should be employed, and at what costs.

VOLUME

Another variable that needs to be taken into consideration is the volume of biomass to be processed. The more volume, the greater the amount of product produced, the more that needs to be processed, and so on.

With a turnkey solution, the chances of having equipment that doesn't meet the needs of your capacity is increased. Certainly, having equipment that can’t easily process your quantities of oil can create bottlenecks, impact profits and result in frustration. Conversely, spending thousands of dollars on equipment that is far too big for your needs is just simply wasted spend and will delay a positive return on investment.

When deciding on ancillary equipment, be realistic about your capacity and goals, and work on a solution that will appropriately meet your needs both now and for the future.

FACILITY & LOCATION

Ancillary equipment takes up space. Depending on the size and layout of your lab, you may require different types of equipment, or need to examine options to utilize your square footage in the most efficient ways. Proper layout and design of your lab space can improve opportunities for positive returns and assists with workflow.

More than just your layout, the actual geographic location of the lab can have a huge impact on your ancillary needs. Regulations vary state by state, county by county, and town by town. What works in one location could be illegal in another and create huge obstacles for operations. Knowing the local regulations can impact what types of equipment are needed, the engineering of the room, and even the volumes of solvent that are allowed.
Selecting the right equipment to use in your facilities is an integral step, and a fitting solution isn't likely to be found in an out-of-the-box combination.

MAKING THE RIGHT CHOICE

Working with consultants and experts is a great first step to take when choosing ancillary pieces. A knowledgeable resource can help you navigate the challenges of product, volume, facility and location, and eliminate disappointment down the road. There's no worse feeling than uncrating your equipment, only to find it won't meet your needs or help you reach your goals.

At Vitalis, our ancillary team evaluates and works with multiple vendors to help our clients get the right equipment, every time. By having an idea of your product goals, volume needs, and the local regulations in your area, you'll ensure that our team has the correct information to formulate an optimal solution that will work for you. In an area where cookie cutter solutions aren't appropriate, a real turnkey solution is a custom-planned ancillary program, facilitated by an expert team.

To speak with somebody about your lab design and ancillary needs, contact our Ancillary Sales Team.

CO2 Selectability

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One System, Many Products

In the ever-expanding cannabis market, companies in the business of extraction cannot afford to overlook CO2 extraction systems to successfully address market demands and thereby increase their own profit margins.

CO2 extraction systems provide the power of selectability to the extract-production process. Using a CO2 system as the foundation of an extraction business provides the flexibility to select specific compounds for top products, produce those products, and deliver them on demand.

Vitalis Director of Sales, Jason Laronde, illuminates the concept of “selectability” and how it responds positively to market forces:

“The really unique thing that CO2 extraction has to offer is that it’s super-selective. Depending on how the machine is set—the pressure, the temperature, the flow rate that you use—the crude cannabis oil can be used in the different products.

“While other extraction methods are really great at making one thing, CO2 is really great at making whatever the customer wants, or whatever the market is asking for.

“So, you’re not only investing in a machine that caters to what customers want now, you’re investing in a machine that can make distillate in the morning and sugar wax in the afternoon. As the market starts to shift, you can adjust with it and in really short order, stay relevant in the customer’s eyes.”

If a company specializes in whole-plant cannabis oils, distillates, or other forms of extracts, just one CO2 extraction system can facilitate these popular formulations. CO2 extraction gives a business the ability to extract a broad spectrum of compounds, making it easier for processors to modify their product offerings in response to market pressures.

Selectivity is a key benefit to using CO2 systems, since it allows for the extraction of specific compounds or combinations of compounds with just a few small adjustments. Utilizing a CO2 extraction system enables the facility to become a multi-product production line. Selective extraction of multiple compounds can be accomplished by modifying the solvent power of the supercritical fluid in the system by adjusting temperature and pressure during extraction. For example, companies can target terpenes in the morning, then switch parameters and focus specifically on THC and CBD recovery in the afternoon.

By using CO2 extraction systems, industrial concentrate makers can produce clean cannabis extracts with the consistency of oil, shatter, budder, or wax. The flexibility of CO2 machines means that products can be made much more economically at scale than they would be if producers used a separate machine for each product.

Terpene Preservation

Generally, extraction is designed to pull a compound or a selected entourage of compounds from plant matter. CO2 extraction, with its ability to perform along a wide spectrum of temperatures and pressures, is a delicate process that won’t damage fragile constituents when performed correctly. For this reason, it is ideal for cannabis, as well as the food, pharmaceutical, and fragrance industries.

Cannabis concentrates are essentially a targeted assortment of cannabinoids, terpenes, and other desired compounds from the cannabis plant. For a successful extract producer, the goal is to consistently achieve effective therapeutic or enjoyable recreational products.

A broad spectrum of terpenes within the extract is crucial to recreational concentrate connoisseurs. What’s more, current clinical studies are suggesting that terpenes can enhance the medicinal properties of CBD and other cannabinoids. Although this “entourage effect” needs much more testing and study for confirmation, current research is very promising.

With changes to temperature and pressure in the extraction process, the system can preserve delicate terpenes from the strain being processed. Given the array of terpenes extracted alongside cannabinoids, CO2 extraction can satisfy top-of-the-market medicinal and recreational consumer demands.

The Economy of Potency Variation

In a study performed in 2017 by Harvard Medical School, researchers found that the majority of medical cannabis users chose cannabis oil over smoking dried cannabis flower and that, “the preferred methods are taking cannabis oils in capsules, inhaling via vaporizers, vape pens, and consuming [cannabis] oil in food or tea.” This new consumer trend can be attributed to a pair of factors - dosage control and perceived economy.

Typically, recreational THC-driven extracts contain anywhere between 60% and 99% THC, with each product having its exact potency explicitly defined for consumer to consider. Comparatively, the average Marijuana flower before extraction contains only 15-25% THC.

Because consumers are now given a wider variety of delivery methods with a broader range of potencies, it is easier for them to adjust dosages for themselves. Previous efforts to control dosages were limited to the consumption of flower through the imprecise method of smoking. Consumers could be instructed to smoke "a lot" or "a little" until noticing the prescribed effects, managing dosages in anecdotal fashion based on any number of subjective consequences. Even further, although the potency of a particular strain could be identified, the combustion of the plant material could potentially burn off a percentage of the desired compounds, depriving the consumer of the full measure of the dose.

Consumption of oils, edibles, and other products allows for more direct consumption, and minimizes the risk of lost compounds. For example, consumption of a 10mg edible eliminates potential loss due to combustion and provides a specific measure of the actual amount being ingested.

The subject of consumption efficiency is certainly a mitigating factor in consumer perception as well. In a long-term study performed by New Frontiers, statistics showed a steady increase in the perception that consuming concentrates saved money.

In present terms, consumers feel that when they are consuming a specific dosage through non-smoking means, they're generally receiving more bang-for-their-buck. Though dosage control is certainly a more measurable and objective factor, consumer attitudes suggest a more subjective feeling that they are able to obtain higher dosages in smaller packages - smoking a gram of flower is being perceived as far less cost-effective relative to consuming a single edible with similar potency.

Cascading down into the market, consumers can experiment with dosage control themselves through more “cost-effective” methods. If a formulation is having successful intended results on a broad level, consumers can begin to measure their product more precisely and experiment with more suitable dosages at perceived economical savings. As a result of these two factors, concentrate sales are now matching or exceeding dried flower sales in most regions within North America and Europe.

Added Benefits

Of course, when we look at CO2 extraction, there are other benefits as well, including the “residual-free” nature of the extracted oils as CO2 readily evaporates out of the oil at atmospheric conditions. Furthermore, running supercritical or liquid CO2 through raw cannabis plant material kills most microbial contaminants. In addition, CO2 concentrates taste as good as those from hydrocarbon, as CO2’s excellent terpene preservation leads to a great tasting product.

Ultimately, as the consumer market shifts to favour certain product formulations, CO2’s tuneability allows processors the ability to tweak their extraction process and flex with the shifting market to stay ahead of the curve and stay successful. As the market shifts, the processor can shift in response to customer demands for cleaner, greener, broad-spectrum oils.

Introduction to CO2 Extracts & Products

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In recent years, a rising trend amongst cannabis consumers, both recreational and medicinal, has been the use of cannabis extracts. However, as consumers and patients become more sophisticated in their purchasing habits, so too do their expectations. Market demand has leaned towards a cleaner and more consistent extract, and one extraction method that has answered the demand uses supercritical CO2 (SC-CO2). The use of SC-CO2 as an extraction solvent has risen over the past few decades in various other industries, such as essential-oil extraction and coffee decaffeination. As for cannabis, SC-CO2 extracts are increasing in popularity since they are both cleaner and safer than organic-solvent-based extracts.

The SC-CO2 Method

Carbon dioxide (CO2) becomes a supercritical fluid when the temperature and pressure of the CO2 pass a critical point; 1071 psi and 87.98 F. At this point, the fluid can dissolve solutes but also diffuse like a vapor through solids. Extracts using the SC-CO2 method are made by passing fluid, or SC-CO2, through cannabis tissues at high pressure, then reducing the pressure to separate the extract from the CO2. Depending on the temperature, pressure, and duration of each extraction run, the resulting extract can vary in color, viscosity, and content of cannabinoids and terpenes. Many extracts are then further processed to produce an extensive variety of products available to the market today.

Cannabis oil creation and use

Oil, the liquid form of a CO2 extract, can be consumed in a multitude of ways; it can be smoked, vaporized, or ingested after being further processed into edibles. Before use, though not always, the oil is separated from the waxes and lipids that remain in the extract. The most common separation method, winterization, is the process of dissolving the extract in ethanol then freezing the mixture, which allows the undesirable components to precipitate, or separate, out of the mixture. The ethanol contained in the remaining extract is then removed via distillation, and the finished oil usually contains anywhere between 45-80% cannabinoids. Manufacturers can make oils containing less wax and lipids by using subcritical extraction methods, thus diminishing the need for winterization.

Vaporizing through the use of a vaporizer or vape pen is a popular method of oil consumption due to its convenience, cleanliness, and discretion. Vape pens, which come in both disposable and reusable variants, are typically filled with 0.25 to 1.0 ml of oil and work differently based on the viscosity and content of the oil located within.

Distillation of cannabis oil offers a heightened purity, potency, and versatility to consumers. Distilling, a process of refinement, separates and isolates cannabinoids from other compounds within the oil. The result is the purest form of cannabis extract, strongly resembling honey in both color and consistency. Like oil, distillate can also be consumed in a variety of ways but, due to high viscosity, must be mixed with a carrier oil before use in a vaporizer pen.

Wax and Shatter

Wax, shatter, and crumble are highly concentrated cannabis products that can also be smoked or vaporized. Traditionally, these products were made using methods such as butane extraction, but manufacturers have recently shifted to alternate processes. Waxes and shatters are produced by first creating the desired consistency of oil through varying the extraction conditions, then using evaporation and/or mixing techniques to achieve the desired product form. Depending on the oil consistency and level of agitation provided, shatter, crumble, or wax is formed. It is important to note that crystalline extracts such as shatter require starting with non-decarboxylated cannabis, as THCA is what forms the crystalline structure on a molecular level.

Edibles

Edibles are commonly made by mixing oil or distillate with an intermediate cooking product such as fat, olive oil, butter, coconut oil, avocado oil, honey, or syrups or glycerin, to be then added to the desired end product. In mixing the cannabis oil with fat, consumption will transport cannabinoids to - and be broken down by - the body’s lipid metabolizing system, resulting in the “body high” that so often assists with pain relief and other such conditions.

Prior to the production of edibles such as cookies, brownies, or gummies, manufacturers first decarboxylate, or heat, their oil or flower to activate the cannabinoids within. THC-acid or THCA, the precursor to THC, is a non-psychoactive cannabinoid with poorly understood therapeutic effects. THCA must be heated, or decarboxylated, to approximately 105 °C (220 °F) under ambient pressure to turn it into its psychoactive successor THC.

Cannabis oil can also be deposited into capsules or tinctures for easy and precise consumption. Capsules are available in various potencies depending on the amount of carrier oil used and allow for an accurate and discrete form of consumption. Traditionally, a tincture is made by dissolving oil in ethanol, with the potency of cannabinoids such as CBD extracted dependent upon alcohol content. Finished tinctures are placed in vials with droppers, allowing for precise quantities to be placed under the tongue.

Medicinal Use

When applied topically, the effects of analgesic and anti-inflammatory cannabinoids, such as CBD, are apparent. Essentially, cannabis-infused topicals are made by mixing cannabis oil, cooking oil (such as coconut oil), and wax together with heat. Because psychoactive cannabinoids are not needed for the medicinal efficacy of topicals, decarboxylation is not required.

CBD suppositories infuse fat (vegetable oil, olive oil, or coconut oil) with cannabis oil. As with edibles, the THCA must be first decarboxylated to produce a psychoactive effect. Cannabis suppositories are known for their quick onset and remain a viable option for those who cannot ingest or inhale cannabis. Once inserted, cannabinoids are rapidly absorbed into the bloodstream as the suppository comes into direct contact with the intestinal wall. Suppositories are an efficient way of absorbing cannabinoids into the bloodstream.