Recent Advances in Supercritical CO 2 Winterization

Supercritical carbon dioxide (CO 2) extraction is a processing technique that pressurizes CO 2 at carefully controlled temperatures to extract terpenes, cannabinoids, and other plant molecules. Once the extract is obtained, the crude oil is typically subjected to an ethanol winterization process to remove chlorophyll, fats and waxes.co2 extraction equipment manufacturer:

Green Mill Supercritical is a Pittsburgh-based manufacturing and engineering company dedicated to the extraction of cannabis and hemp. The company offers a range of CO 2 extraction equipment in which users can adjust and control their extraction methods. They recently announced a technological advancement that allows for winterization of the process, potentially eliminating the need for winterization of ethanol.

We spoke with Jeff Diehl, Director of Marketing for Green Mill Supercritical, to learn more about the new process.Jeff was invited to join Green Mill in 2017 by Jeremy Diehl, founder and CTO of San Francisco, where he was working in the tech industry.

Aaron Green: Before you introduce your new technology, can you explain the industry trends you're looking at?

Jeff Diehl: One of the big things I want to note is the premium extraction space. More and more consumers are demanding higher quality extracts. They want differentiated products. They want products that are safe and have some kind of meaningful connection to the particular plant they come from. Currently, CO 2 plays only a small role in the market for these products. Most quality products are generated through hydrocarbon extraction. So I'm looking at how people are using CO 2 to produce the next generation of safe, quality products.

Aaron: What is the normal process for extracting CO 2 today?

Jeff Diehl, Director of Marketing, Green Mill Supercritical
Jeff: The current CO 2 extraction process typically consists of two main stages to produce the final extract. In the first stage, you will extract the crude oil at the point where it is extracted. The second stage is post-extraction, where cleanup is performed to obtain refined oil. In this post-extraction phase, most operations include an ethanol-based winterization process.

Aaron: What is the role of the winterization step?

Jeff: The anti-freeze is to remove the wax. Your primary extract is considered a crude extract because it extracts a lot of unwanted material from the plant. Most of the unwanted material is wax. Winterization is the process of separating the wax from the cannabinoids using a solvent (usually ethanol). The multiple challenges inherent in ethanol-based antifreeze technology can result in cost, time and product loss. It is very inefficient. In addition, there is always ethanol left in the final product, which is not appreciated by consumers.

Aaron: You recently announced a new process at Green Mill that moves the antifreeze step to a supercritical CO 2 facility. Can you explain how it works?

Jeff: In the process we call real-time antifreeze, the antifreeze no longer involves ethanol. In the initial extraction process, it's all done with CO 2. This is a major advancement in our process, and although it has been tried before, no one has done it successfully in a workable way. You typically have a four-day process - one day for CO2 extraction and three days for ethanol winterization - and the entire process is done in less than a day. We have the automated software, sensors and pumps to make this possible.

Aaron: How does the quality of the resulting product compare to the new process?

Jeff: If you are completely familiar with the extraction function, you can immediately see the difference. It looks clean and bright. So far, the lab analysis has been very positive, but we continue to test. Our R&D team has run several tests, mostly on cannabis and CBD. That's because we don't have a license for THC. We are currently working with our licensing partners so that we can collect more data on THC-containing products to provide accurate numbers. However, for CBD, we have conducted multiple tests to validate the method and technology and have consistently seen excellent results in terms of product purity and process efficiency.

Aaron: How do the benefits compare between the processes?

Hemp CBD extracts are extracted directly from a Green Mill SFE Pro running real-time anti-freeze.
Jeff: From the data we've seen in the industry, when you winterize with ethanol, there's 5 to 10 percent of cannabinoids left in the wax. That's just lost. By using CO 2 for real-time winterization, we have found recovery rates as high as 99%. We'll continue to investigate that result through testing to make sure it's not an outlier, but the recovery rate looks promising anyway.

Aaron: Another issue with ethanol is taxation and the ability to find food-grade supplies. What are your thoughts on this that you can share?

Jeff: There are many benefits to getting rid of ethanol. The absolute amount of ethanol is a factor. There are a lot of regulations and fire requirements regarding managing large amounts of ethanol. The ethanol winterization process is not just a process in itself. There are multiple stages, from blending to freezing, filtering to solvent removal. These are all opportunities for error, so you always have to manage these risks. Multiple large pieces of equipment, including fume hoods, filter skids, freezers and rotary evaporators, are expensive and require heavy management.

I think Elon Musk said the best process is no process at all. Anytime you can remove a step from a process in an industrial process, that's the direction you want to follow. And that's what we've done. With this latest work, we have effectively removed post-processing from certain categories of final products.

Aaron: Do you have any patents on the new process?

Jeff: We have a patent pending on both the method and the device, which allows us to talk as much as we can about our topic.

Aaron: So, how would this work if someone already had existing Green Mill equipment? Is this something that can be retrofitted? Is it a software upgrade?

Jeff: There are two components. One is an equipment upgrade that can be done retroactively for an existing customer, and the other is a method upgrade that we provide to help our customers. The automation software inherently can handle the setup needed to run the method. In fact, it's the software and the rest of our existing technology stack, the proprietary pumps, the triple in-line fractionation, the accuracy and stability of the entire system that makes this chill-proofing possible.

Aaron: Where are you launching first? Do you plan to go international?

Jeff: International is definitely in the plans, as we have already sold systems abroad. We are currently preparing to announce the launch of a Beta program using the new technology. So we are not ready to sell this product widely at this time, but we are accepting proposals from companies that want to join and join us early on at the forefront of CO 2 extraction innovation.

Aaron: Okay, great. Thank you Jeff, that concludes the interview.