Closed-Loop Extraction Components:
To successfully perform closed-loop extraction, you will need more than just a closed loop. Please refer to the following list of BVV recommended components. Each component will be discussed in detail.
-2. Vacuum Pump
-5. Refrigerant Scale
-6. Vacuum Oven or Vacuum Chamber w/ Heat Pad
-7. Dry Ice and Buckets
-8. Active Recovery Kit (optional)
-9. Explosion Proof Fan, Ventilation
1. Closed Loop Extractor
There are many options for closed loops and upgrades but to start, we recommend a standard 1lb top fill unit. It is best to start with a basic system so that you can learn and build your extraction knowledge. Moving solvent through a 1lb top fill system is much easier than moving solvent through a 5lb active rack. But, once you have mastered a standard top fill unit, larger more complex units will no longer be a mystery (Advanced extractors will be discussed in a future post).
2. Vacuum Pump
The Vacuum Pump will be used to pull the inital vacuum on your system. Pulling a vacuum on an extractor will allow solvent to move much more easily through the system. It will also allow you to keep a clean atmosphere inside. The vacuum pump will also be used to pull a vacuum on your empty solvent recovery tank when you are ready to recover your solvent. And lastly, the vacuum pump will be used to pull a vacuum on your oven or chamber when it is time to purge your extract of residuals.
The solvent you choose will depend on experience and personal preference. We recommend starting with 100% N-Butane. N-Butane will have a lower pressure than Propane and will be easier to use when starting to extract. We recommend 5 lbs of solvent per pound of material. This means that if we are using a 1lb closed loop extractor, we want to use at least 5 lbs of solvent. Depending on how tightly you pack the column, you can use slightly less or slightly more solvent. Anywhere from 4-7 lbs will be acceptable. Once you feel comfortable with N-Butane, you might want to try a 70/30 mix of Butane and Propane or straight Propane. But, be ready to experience higher pressures with these two types of solvent.
4. Solvent Recovery Tank
The solvent recovery tank should match the capacity of the extractor you are using. If you are using a 1lb closed loop, you want to use a recovery tank that holds at least 5lbs of solvent. Using a larger recovery tank will give you increased vacuum pull when recovering and allow you to hold more solvent. There are two types of tanks: Carbon Steel and Stainless Steel. Carbon steel tanks are the same type of tank you would purchase for your grill at home. They usually come in a different color such as yellow to indicate that they are recovery tanks. Stainless Steel recovery tanks will help keep your gas cleaner. Carbon steel tanks can rust with time and use, so stainless steel tanks are a must when making clean and proper medicine.
5. Refrigerant Scale
Before inputing solvent into the system, use a refrigerant scale to weigh out the amount of gas in the tank. Each tank will have a tare weight (empty weight) clearly labeled somewhere. As you input solvent into your system you will see the weight begin to drop. This will allow you to input the correct amount of solvent into the system and prevent over filling. When you are ready to recover, it is a good idea to place the recovery tank on the scale to determine how much solvent you are recovering as well as how fast you are recovering. You are likely to lose a small amount of gas each time you run because some solvent will get trapped in the material and lines. This small amount is negligable. Using a refrigerant scale will allow you to accurately gauge solvent levels throughout the entire process.
6. Vacuum Oven or Chamber w/ Heat Pad
Depending on the return, you will either need a vacuum oven or vacuum chamber to purge the residual solvent from your oil. The oven or chamber is also used to polish your extract. A vacuum oven and vacuum chamber operate on the same principal. Inside of a vacuum, the boiling point will be lowered considerably. The residual butane will begin to boil off and evaporate without any heat applied. The heat will allow the process to happen more quickly and efficiently. As a starting point, set the chamber or oven to 100F and purge for 24-72 hours. Temperature and time will be dependant on material, temperature of extraction, and desired end product.
7. Dry Ice and Buckets
You will need dry ice for recovery. Dry ice is always recommended. Regular ice does not have the thermal capacity to keep up with recovery. Dry ice will speed up the process considerably. You will need a bucket for holding dry ice and your recovery tank as well as a bucket for holding warm water and your extractor during recovery.
8. Active Recovery Kit (optional)
For large scale processing, we recommend using an active recovery setup for speed and efficiency. Setup and operation of active components will be discussed in a future post. The active recovery kit will allow you to mechanically recover solvent via the recovery pump. Additon of an active setup to your system will add quite a bit more components but, will give you many more options for advanced techniques and recovery speeds.
9. Explosion Proof Fan, Ventilation
It is extremely important to have the proper safety equipment and planning when performing an extraction. It is highly recommended that you use an explosion proof fan. At minimum you should have adequate ventilation. Do not run any electrical equipment near your extractor.