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CO2 advantages over butane extraction.
There are several types of extraction solvents, and two of the most popular are Butane Hash Oil (BHO) Extraction and CO2 Extraction.
Why butane hash oil extraction?
Unlike CO2 (Carbon Dioxide), Butane is considered a volatile and flammable solvent, which means operators have to take additional precautions to get regulatory approval. Butane is quick, and it also allows the operator to create products like live resin. BHO systems are typically cheaper than CO2 systems, but the peripherals and required safety equipment will likely outweigh any cost savings. Even a butane closed loop system needs additional safety equipment, like an explosion-proof room to house the system in.
Why CO2 extraction?
CO2 produces a cleaner product than BHO. Some systems, like the Apeks Supercritical Duplex™ system, are optimized for low pressure, low temperature (subcritical) runs. This means that the extract can be used as is, without the need for further distillation. The extract won’t contain undesirable elements, like plant waxes and fats. Butane extractions will always leave some trace elements behind, even if it’s parts per million. In a medicinal product, even parts per million is not acceptable.
In some states, the only types of butane extractors allowed are those that recover all the butane through a closed-loop system. Butane is sneaky though and some will escape and can be disastrous. Not all closed-loop systems are created equal so it is extremely important to do research before making the purchase to ensure that the manufacturer conforms to safety standards. In addition, there are extra costs associated with the set up (closed-loop or not) that are required by regulators, such as explosion-proof facilities. What else does a butane operation need?
Ventilation
The room needs to be properly ventilated. As stated above, even closed-loop systems will leak out butane, even if it’s an operator error as they empty the vessel after a run. A dilution ventilation system will keep the butane in the room at a level low enough that it’s not explosive anymore. This is called the Lower Explosive Limit (LEL) and butane is 1.6% in air. By comparison, CO2 will require a CO2 monitor but even a significant leak won’t explode. Another kind of ventilation called local exhaust ventilation captures the butane and pumps it outside. This type of ventilation would be a hood exhaust fan.
Gas Detection
A Butane leak is not immediately identifiable by smell, especially in low concentrations. By the time you smell it, it’s dangerously close to the upper level of LEL, so it’s important to be aware of any leaks long before you can smell the gas. Operators should use both hand-held devices and wall- or ceiling-mounted devices. It’s important to calibrate the devices to detect butane – it is usually not the default setting.
No sparks!
It goes without saying that anything with a spark, such as an ignition switch or even a spark from an outlet, should be completely banished from a butane operation. Pools of butane may have gathered (it is heavier than air) without the knowledge of the operator and one spark is all that’s needed for an explosion.
Extraction booth (aka a bomb shelter)
In addition to the ventilation requirements, butane systems typically require a purpose-built room that will contain an explosion. These extraction booths/bomb shelters can cost thousands of dollars and again, it’s important for people to do their research before selecting a model. Safety standards in other countries may not be quite as strict as they are in the US, which means the booths may not comply with regulators in this country.
Storing butane
Butane should be stored in a separate area from the processing area, preferably outdoors in a cage. The quantity in storage should be limited and anti-crash bollards added to the cage to prevent a car reversing into it.
Work environment
Butane should be stored in a separate area from the processing area, preferably outdoors in a cage. The quantity in storage should be limited and anti-crash bollards added to the cage to prevent a car reversing into it.
Safety protocols
In addition to the above, butane facilities should have a fully tested and working safety protocol in place. All employees should know exactly what to do in the case of an explosion or fire and regular drills are needed to keep everyone updated on the protocol. Plans should be documented and posted in public places. This documentation includes directions to the nearest emergency room and evacuation processes.
Local regulations
The local fire department has to fully inspect and certify most operations. They will review the extraction system, the facility and all implemented safety protocols. Without the green light from regulatory bodies, the business cannot start extracting. All equipment should be rated either UL or ETL which are accepted safety standards. Engineer Peer Review documentation is also sometimes required and if it’s not a requirement, it does go a long way to reassure the fire marshal of the equipment safety. Some municipalities are requiring all systems to be closed-loop and some are banning butane outright (Los Angeles).
Butane extraction advantages
- Able to process Live Resin
- Low equipment cost
- High yields
- Faster extraction times
Butane extraction disadvantages
- High facility and peripheral costs
- Explosive
- Residual solvent
CO2 extraction advantages
- Peripheral costs are lower
- No safety mechanisms other than a CO2 monitor
- No bomb shelter
- No separate storage area required
- Easier to certify
- Regulatory bodies are more likely to approve a CO2 operation than a BHO
- CO2 may be required by law in certain municipalities
CO2 extraction disadvantages
- Cost of equipment
- Slower extraction times
So which system?
Despite the savings on initial costs of butane systems, the peripheral equipment may offset any savings. Bomb shelters don’t come cheap! CO2 systems have the initial expense, but the only peripheral equipment needed is a CO2 monitor. Larger systems will need HVAC equipment to keep the room cool but most new large Apeks systems are equipped with an external chiller, which means the room doesn’t overheat.
However, in all instances, we at Apeks ask “What are you trying to produce” before we move any further. This is because the extraction system might be determined by the end product. The chart below shows which extraction type works best for each type of product. If a customer wants to produce Live Resin, Butane extraction is the way to go. For vape pen cartridges, terpenes and edible oils, CO2 is a fantastic choice!
Best practices
To ensure compliance with local regulatory bodies, it’s best to develop a checklist of required equipment before determining the extraction method. Armed with the checklist, you can then price each piece of equipment and then make the decision about which extraction system to purchase. In some cases, butane extraction will be the equipment of choice, but more and more operators are choosing CO2, despite the higher initial outlay.
Conclusion
The entire industry is slowly moving towards more regulation and control, with government oversight from everything to packaging and presentation, to extraction methods. A butane system leaving parts per million in medicine may not get the green light, but a CO2 system with no remaining extract will receive a warmer welcome. Consumer demand will also require a greener, healthier product – an organic brand will not pass certification if it contains any solvent. A subcritical/terpene run from a CO2 system won’t pull any undesired plant material, therefore there’s no post-processing required, and all that’s extracted is pure botanical oil, ready for a vape pen or an edible.
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Apeks Supercritical extraction systems use carbon dioxide (CO2) as a solvent to extract oil from botanical plant material because it yields safer, cleaner and purer oil.