Thanks to the 2018 Farm Bill, hemp is legalized federally and continuing to expand in popularity. Last year, the United States saw nearly 80,000... Getting Started in Hemp Extraction: Step One: Choose Processing Method

Thanks to the 2018 Farm Bill, hemp is legalized federally and continuing to expand in popularity. Last year, the United States saw nearly 80,000 acres of licensed industrial hemp grown in 23 states (more than tripled from the year prior), and over 3,500 state licenses issued. The numbers aren’t out for 2019 just yet, but hemp’s high growth rate in the marketplace is predicted to continue accelerating. 

At Root Engineers, we specialize in the engineering and design of cannabis cultivation and processing facilities across the country. In the past year, we’ve undoubtedly seen an increase in the number of hemp extraction facility design projects our team has undertaken. CBD and other hemp extracts are exploding when it comes to consumer popularity, and more and more players are joining the hemp extraction game. In this three part series, we’ll outline the steps to getting started in hemp extraction, starting with Step One: choosing a processing method.

When designing cultivation facilities or other business types, the design process typically starts with first choosing a property, then choosing a building, and then designing the equipment and systems to outfit the building. When it comes to hemp extraction, we actually recommend the opposite: start with choosing your processing method, then design your facility and systems, and finally choose a property that will work for the building you have designed. 

Hemp extraction typically involves the use of hazardous materials, which can affect a number of building and property codes and regulations. In addition, the size and quantity of hazardous materials can make a big difference in facility design and considerations, such as where materials will be located. If you choose your building and/or property before you’ve defined which extraction method you’ll be using, you may find yourself in a position where the building and/or property you’ve purchased won’t actually work for your facility – which is a major setback for both your schedule and your budget. Thus, we begin with extraction method considerations. 

Methods of Extraction

Every detail of your hemp extraction facility design will depend greatly on the method you choose to use for extraction. There are three main methods of processing hemp that we see most often: ethanol extraction, CO2 extraction, and the less common hydrocarbon extraction. (Note: while we have seen and continue to see a lot of small scale cannabis companies choosing hydrocarbon facilities to extract THC, we are seeing less of it in the hemp arena and will focus on ethanol and CO2 extraction methods below). 

Ethanol extraction involves using alcohol to draw out cannabinoids like CBD and other beneficial compounds in the hemp plant. Ethanol is a high-proof grain-based alcohol that is used as a solvent, allowing minimal damage to the plant while extracting important compounds. Ethanol extraction is typically a quicker and less energy-intensive process when compared to using CO2, and the necessary equipment is generally less expensive and easily scalable. However, when alcohol is combined with heat or the risk of spark, there is an extremely high flammability risk, which leads to increased considerations in both equipment selection and facility design. Electrical systems and ventilation both need to be designed with flammable gases in mind.

CO2 extraction uses CO2, or carbon dioxide, as the solvent to extract compounds from the plant. CO2 is sometimes considered a cleaner or purer form of extraction because there is no solvent residue left over after processing. In terms of hazardous considerations, CO2 is nonflammable which leads to fewer facility safety requirements and costs, but it is an asphyxiant so does require alarms and exhaust fans in the event of a CO2 leak. Because of the complex equipment required for CO2 extraction, upfront costs tend to be higher, and therefore we often see larger, higher throughput facilities lean toward ethanol in lieu of CO2.

Questions to Consider When Choosing Your Extraction Equipment

  • What kind of throughput are you looking for? In our experience, large throughput hemp processing facilities are leaning toward ethanol extraction equipment, while smaller facilities may lean toward CO2. Ethanol equipment scales easily and is less expensive to purchase and operate. However, as mentioned above, there are flammability concerns to consider that you won’t need to worry about if you are utilizing CO2 extraction equipment. (We will dig into this more in the next article in this series.) 
  • What is your equipment budget and overall construction budget? These two questions go hand-in-hand and tend to be inversely proportional. As we indicated, the cost of the ethanol extraction equipment can be appealing in the short-run, but your overall build-out cost will tend to increase with an ethanol process because of the extra measures you’ll have to take surrounding flammability concerns. Speak with equipment suppliers to determine what type of equipment you can afford. Also involve your design team (architects and engineers) at this point so that they can inform you of some of the complications you may run into down the line with each process choice. This will help you plan ahead, saving time and money. 
  • Can your extraction equipment supplier provide a UL-listed extraction system, or a system with third party peer review meeting the requirements of NFPA 1, Chapter 38? This is an issue our clients run into often. Many extraction systems are not UL-listed (or other similar NRTL certified) and if they aren’t, the authority having jurisdiction (or the AHJ, i.e. the building department) will require the system to be peer reviewed, per NFPA 1, Chapter 38 requirements. Again, these systems are often inversely proportional: the non-listed, non-peer reviewed system will likely cost less money, but you’ll need to spend time on the backend finding a qualified person to peer review the system to ensure it’s safe. We encourage our clients to ask informed questions of the equipment supplier such as: Is the system UL listed (or other NTRL from source cited above)? Beware that oftentimes they will answer “yes, all of our parts are UL listed.” This is not the same as the entire system being listed. If the parts are listed but the system is not, ask if the purchased equipment will come with the necessary peer-reviewed report to appease the AHJ per NFPA 1, Chapter 38. Additionally, the Engineer of Record who provided the peer review will need to come out to the site to review the installation, so they can certify that it was installed in accordance with the peer review they provided. If the supplier answers no, then you’ll need to find a qualified peer reviewer, which can cost significant money and time, so you’ll want to factor this information into your decision regarding which extraction system to purchase. 
  • Can the extraction equipment supplier provide a voltage and hertz that is available in the country in which the equipment will be installed? About one-third of our projects involve equipment manufactured overseas in a voltage that is not available in the United States, so a transformer is required to be installed, adding cost and complication to your project. 
  • What is my timeline, is it realistic or does it need to be adjusted based on equipment or construction timelines? Once you decide on your preferred equipment supplier and system, you’ll want to take a fresh look at your timelines. Also involve your design team and contractor in this discussion as they’ll likely have a pulse on realistic permitting and construction timelines.

Real World Case Study

Oftentimes, our team is brought into a project where the processing method has been chosen and the extraction equipment has already been purchased. Unfortunately, many times the owner was not aware of the NFPA requirements for peer review, which at this stage can cause major setbacks in both time and money. 

We had one particular project we were brought into where the client had purchased an extraction system from an overseas provider. The system was not peer reviewed, the equipment was not UL-listed and the required voltage for the equipment was not available at the chosen site. The client spent a shocking amount of time and money trying to get this system to work for their operation, ultimately having to backtrack. In a conversation at the conclusion of the project, the client admitted that had they gone with the higher cost manufacturer they considered in the beginning, they would have saved money and time, ultimately greatly impacting their bottom line. 

Final Thoughts

Designing a hemp extraction facility is a complex process with many considerations to keep in mind. Understanding the correct order of the design and build process, along with building a reliable team and involving them at all crucial points, will be vital to the success of your operation.

Stay tuned for Part Two in this series, where we’ll discuss Step Two: Choose Facility.

Disclaimer: We are not equipment manufacturers, we are engineers. As such, we do not claim to be experts in all aspects of extraction equipment. We are a team of experienced professional engineers specializing in engineering and system design for cannabis processing facilities. The purpose of this article is to highlight the important considerations and complications we have come across in our experience completing over 100 cannabis facility design projects, to allow processors to make a more informed decision when choosing an extraction method. 

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