I am currently running 2 8x36 material Colums with a solvent tank and a cooker with a CMEP recovery pump with a water heater. I’m using 125 lbs of butane every 3 runs. I pile 10 lbs of biomass into each material Colum so a total of 20 lbs per run.
I am averaging around 10-14 % of product after purged
Am I using to much butane? Do I need to upgrade my recovery pump? I was looking into the BVV 4 cyl
What is the average lbs lost of butane in a closed loop system?
Thank for your help
where?
are you pouring it into jars or pyrex and evaporating to atmosphere?
pulling socks with 10lb solvent in them?
You don’t know?
How could you figure that out?!?
hint: how much do your pours weigh? purged?
How about those spent material socks? when pulled? After sitting a day?
yes, that’s way too much solvent.
can you explain how this could be your pump’s problem?
(it could conceivably be…)
eg if one had it plumbed retrovap style…
if it were actually a CLOSED loop, zero.
it’s not.
How about YOU tell us where you’re loosing it.
Then figure out how to MEASURE your losses.
Then we can address how to reduce those losses.
ATM it sounds like you’re pouring way too wet, and letting most of it evaporate to atmosphere. which I imagine you’re doing in an unsafe manner…care to convince the rest of the class I’m wrong? (they love that 
)
Thank for all your responses, I am pouring it into Pyrex dishes, 9x13 when I pour it’s filled 3/4 after purging I go down to about 1/2 a Pyrex dish. Socks come out dry I do have a little butane left over at the bottom of the material Colum I can’t push out fully. I use 125lbs for 3 runs and have a left over amount to fill one Colum but not 2, so I am assuming I’m losing atleast 60-80 lbs for 3 runs after reading all you’re responses.
I also tried the search bar for all these questions but I could not find a specific answer for butane usage in a closed loop system.
What is everyones usage of butane per run with a 125lb butane tank with 2 8x36 material columns?
Get a scale. Do some before & after.
…and come up with a scenario where it’s your pumps fault.
It probably isn’t, but understanding how it might be allows you to rule that out.
Do you understand why you were pointed at the retrovap?
Search queries are hard. Especially when you’re new and looking for basic info.
…but you do have options
——— “butane loses in cls per run” ———
While modern closed-loop systems (CLS) are highly efficient,
butane losses still occur during each run, typically due to solvent absorbed by the plant material and minor leaks. A common rule of thumb for dry/cured material is a 1:1 ratio of lost butane to the weight of biomass being processed.
The precise amount of butane lost per run is not a single, fixed number. It varies depending on several factors:
- Biomass type: Fresh frozen plant material contains a significant amount of water (up to 70–80%). Since water and butane are immiscible, this can affect how much solvent is trapped and potentially lost compared to dry/cured biomass.
- Biomass to solvent ratio: The amount of butane needed for effective extraction is often a ratio to the plant material’s weight. For example, a 5-pound material column might require 25 pounds of butane (a 5:1 ratio). A portion of this solvent will remain absorbed by the biomass.
- Equipment and operational parameters: The quality and maintenance of your CLS, as well as your standard operating procedures (SOPs), play a large role in minimizing loss.
- Recovery method: Active recovery systems, which use pumps, are generally more efficient at reclaiming solvent than passive recovery methods, which rely on temperature differentials.
- Temperature control: Properly controlling temperatures helps maximize recovery. Some techniques involve warming the material column slightly to encourage all the absorbed butane to evaporate back into the system.
- Leak integrity: Even the smallest leaks in seals, gaskets, or connections will lead to gas escaping over time. Regular leak checks are essential.
- Use of media: Running a color remediation column (CRC) with filter media adds another place for solvent to be absorbed, potentially increasing loss.
How to minimize butane loss in CLS
While some loss is unavoidable, you can significantly reduce it with these practices:
- Regular maintenance: Routinely check and replace all gaskets, seals, and fittings. Perform pressure or vacuum tests to identify and fix leaks.
- Optimize recovery: For active recovery, ensure your pump is in good working order. For passive recovery, use sufficient heating and cooling to create an optimal temperature differential.
- Warm material column: Towards the end of the recovery phase, apply gentle heat to the material column. This helps drive any residual, absorbed butane out of the plant material and back into the collection vessel for recovery.
- Proper biomass preparation: Avoid overpacking the material column, which can inhibit solvent flow and recovery. If possible, consider pre-drying the biomass to reduce the water content.
- Add nitrogen assistance: For systems designed to accommodate it, adding a nitrogen assist can speed up the transfer of bulk liquid and reduce process time. However, this may not help with the small amounts of solvent absorbed by the plant material.
Which is not a horrible starting point.