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closed loop cold butane push question

Calwax

Member
hey guys

issue is as follows.

Currently ive been using a chilling coil inbetween my storage and

material column to try and improve my final product,

needless to say i believe I have been yielding less because of it.

i nitrogen push from the storage tank at 100psi to move the chilled lpg

I get all the solvent out of the storage tank.

its dry when I finish my dump.

i use 25 pounds LPG for 4 pound run ( 6x24 non jacket )
is this not enough ?

questionshould i be closing off my storage tank as soon as the last bit of lpg flows out or should i allow the pressurized tank to let it flow through a bit, no? should i only reopen it after my soak and flush once my solvent slows down , as to pressure out whatever is slowly dripping in the column


i flow lpg entry with the dump collection valve open.

once any amount comes through I lock it off and let it saturate

eventually everything starts to ice up because of the chilled coil

NOW RIGHT HERE IS WHERE I FEEL LIKE I MUCK SOMETHING UP.

now once i feel like ive reached the desired soak time because

its all been covered long enough. or whatever.

I pull the dump valve

the solvent flows to the collection pot and its glorious !:tiphat:

(collection pot is has no heat applied during this process)

as the solvent flow to the collection pot slows i send nitrogen through t

the lines in whatver effort to push out whatever keeps dripping.

at a point it just stops completely, Did I chill the material in the

column with n2 and lock up all the flow?

at this point i vent out all the pressure in the system. b4 recovery

because NITROGEN IS COMPRESSIBLE NOT CONDENSABLE

(thank you greywolf)

turn the heat on the collection pot and begin recovery.


now thats my woes.

after the majority of flow is completed and dripping starts and i use

n2 to push the remaining fluid out .
I feel like it dries it out or locks it up.





i
 

Zipsort

Member
Im not seeing anything wrong here, sounds like you're doing everything right. If you're pushing from the top of your columns with nitro and nothing is coming out, sounds like you got it all. You're probably yielding less because you're not picking up as many fats and wax.
 

Gray Wolf

A Posse ad Esse. From Possibility to realization.
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Some thoughts:

6" X 24" is not a very efficient column. Are you using a shower head at the top of the column?

With a 4" X 36" column, we flooded by volume, typically about 2.4V (V X 3 X .8).

6" X 6" X .7854 X 24 = 679 cu/in, so 679 cu/in X 2.4V= 1630 cubic inches LPG required.

1660 cu/in X .0217 lb/in/cu = 36 lbs

Dropping the injection temperature of the LPG reduces both its pickup of non target elements, as well as targeted element. Our volumes were based on extraction temperatures below -30C.

Have you examined the waste material to see if you have intact trichome heads, especially at the top of the column?

If you have a 6" X 24" column, you have 679 cu/in volume, which at 4 lbs/1816 gms loading is about 2.6 gms/cu/in. That is awfully light packing density, which can cause channeling.

With bud we pack closer to 3.6 gms/cu/in and with 10 mesh ground material, about 4.1 gm/in/cu.

How long are you soaking with the dump valve closed?
 
Last edited:

Calwax

Member
Okay A bit has changed since my last post. I believe I have solved most if not all my issues.

I NOW bottom flood by volume (14 fills it up about)

then i close the bottom liquid valve open the top and dump valve

and allow another 14 to wash the rest of the fully packed colomn.

i then run the pump for a little while then shut it off and nitrogen blast

then evac to atmos. at that time i lock off the column and add heat to it and allow

it to recover from the top.

i believe i need to upgrade my recovery lines from 1/4 to 3/8 or 1/2 im not sure .

and yes i do have a shower head.

after checking your numbers im about 10 pounds off but i believe im much closer then i was

when i first started.
 

gumby420

Member
So i get that nitrogen is compressible and not condensable but it’s also inert. Why not just recover it along with the lpg and just closely monitor your tanks PSI levels. Isn’t that really the worst thing that could happen? PSI spikes? Or is there something else I’m missing with using nitrogen. I’m currently using vapor assist, I’ve used nitrogen a few times but it ends up taking about 30min longer per run and I feel like when off gassing I lose lpg as well as nitrogen. So technically couldn’t I just recover it like normal and then when I evacuate my lines at the end of the day vent it out of the solvent tank then? Sorry I know this is no help to your question but I’ve been wondering this for a while. I know one guy that does is the way I described, but definitely want other opinions
 

Gray Wolf

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So i get that nitrogen is compressible and not condensable but it’s also inert. Why not just recover it along with the lpg and just closely monitor your tanks PSI levels. Isn’t that really the worst thing that could happen? PSI spikes? Or is there something else I’m missing with using nitrogen. I’m currently using vapor assist, I’ve used nitrogen a few times but it ends up taking about 30min longer per run and I feel like when off gassing I lose lpg as well as nitrogen. So technically couldn’t I just recover it like normal and then when I evacuate my lines at the end of the day vent it out of the solvent tank then? Sorry I know this is no help to your question but I’ve been wondering this for a while. I know one guy that does is the way I described, but definitely want other opinions


It takes (much) longer to recover, the heat of compression heats up the mix, and you can eventually reach the pump shut off pressure.
 

Calwax

Member
greywolf- do you prefer a hot loop to move the last amount of solvent from the column or a nitro push?
 

Gray Wolf

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greywolf- do you prefer a hot loop to move the last amount of solvent from the column or a nitro push?


If I need a push, I use a secondary hot vapor tank.

I also heat the columns to 150F after draining, to force out any remaining LPG, and then back fill with nitrogen so that when I open the column, it is below 10% of LEL.
 

Calwax

Member
do you keep your the column open when first applying heat and let it push down, wouldnt that 'ruin' the color?
 

Gray Wolf

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do you keep your the column open when first applying heat and let it push down, wouldnt that 'ruin' the color?


When I turn on the column heat, I valve off the column and recover it separately from the pot.
 

Gray Wolf

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Does using hot vapor to push the butane contaminate the color?


Depends on how you do it. If the hot vapor is just providing head pressure to the supply tank, it doesn't.
 

Dab Strudel

Active member
If I need a push, I use a secondary hot vapor tank.

I also heat the columns to 150F after draining, to force out any remaining LPG, and then back fill with nitrogen so that when I open the column, it is below 10% of LEL.

When you need a push, what's the method to not ruin your extract color yet use the power of pressure? Can you use a room temp tank or does it need to be heated to have some built pressure behind it? I am thinking you have a hose connected to the vapor side of the tank and just crack the valve. but do you keep the pressure below a certain number or do anything special at this time that makes or breaks the assistance?
 

Gray Wolf

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When you need a push, what's the method to not ruin your extract color yet use the power of pressure? Can you use a room temp tank or does it need to be heated to have some built pressure behind it? I am thinking you have a hose connected to the vapor side of the tank and just crack the valve. but do you keep the pressure below a certain number or do anything special at this time that makes or breaks the assistance?


Hooking a second hot vapor tank inline to provide head pressure on the supply tank, is what I use. The hot vapor doesn't come in contact with the plant material or extract, because it is providing only head pressure.


I also chill the extraction butane using dry ice or liquid nitrogen and a heat exchanger, after it leaves the tank and before it enters the extraction column.
 
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