Butane Won't Leave My Recovery Tank

[Toker95]

Hey everyone, so I recovered my butane from my closed loop on Thursday. Today I grabbed the tank to use the butane from it for another run although the butane will not leave the tank. I can shake the tank around and feel plenty of liquid in there. When I flipped the valve on my tank to open without a line hooked up I felt the pressure pulling from inside the tank, like it was vacuuming. It seems as if I have the wrong pressure in my tank. Any input would be highly appreciated. Thanks!!

 

[Graywolf]

How cold is your recovery tank? It will pull a vacuum if it is cold enough.

Stick it in hot water and open the vapor valve. Here are the the pressures at different temperatures and mixtures.

 

[12345678989]

Raise the temp, they sell magnetic tank heaters or heating blankets to wrap them in.. same thing happens with freon when it's cold.. be careful, hook a set of gauges up and get a pressure reading.. don't heat the tank without knowing where you stand or you will explode yourself

 

[Toker95]

Thank you guys for all the answers. I did as you said, and got the butane to release. I appreciate the chart GW!

 

[DjangoNugs]

How cold is your recovery tank? It will pull a vacuum if it is cold enough.

Stick it in hot water and open the vapor valve. Here are the the pressures at different temperatures and mixtures.

Yeah Nice chart GW slightly confused on how to utilize it..this keeps happening to us lately. Only since it started getting cold out. Want to make sure I'm following you guys. Say I open the valves to let the solvent run through my tube and it stops flowing, is it because of pressure problems? We seem to only be able to fit a third of the needed gas solvent in our tubes, whether they are the 5lb or 2lb tubes, with three more subsequent soaks if possible. Do we need to keep the solvent tank warm while letting it flow; or shut off the liquid valve to stop solvent flowing through it, put tank in warm water, subsequently opening vapor valve to release gas and lower pressure? Or do those tubes only hold so much? Been pondering this one for a while now. Hope those questions make sense.

 

[Graywolf]

Yeah Nice chart GW slightly confused on how to utilize it..this keeps happening to us lately. Only since it started getting cold out. Want to make sure I'm following you guys. Say I open the valves to let the solvent run through my tube and it stops flowing, is it because of pressure problems? We seem to only be able to fit a third of the needed gas solvent in our tubes, whether they are the 5lb or 2lb tubes, with three more subsequent soaks if possible. Do we need to keep the solvent tank warm while letting it flow; or shut off the liquid valve to stop solvent flowing through it, put tank in warm water, subsequently opening vapor valve to release gas and lower pressure? Or do those tubes only hold so much? Been pondering this one for a while now. Hope those questions make sense.

On a passive system, the size of the tubes and size of the catch tank need to be more balanced than with an active system.

What are the dimensions of your tubes and of the catch tank?

Once you introduce the LPG, the vacuum is lost, and you have to concern your self with how the vapor makes it out to make room for the liquid that it is holding back.

If the system and lower tank are colder than the boiling point of the LPG under vacuum, and the LPG used is below its boiling point, little vapor is formed, so there is less of an issue.

Does your passive system have a center dip tube, or is it flush with the lid? If it is a system designed to be active and being used passively, it may have a diptube which will restrict flow into the lower tank, once the fluid level reaches the bottom of the tube. If so, you can drill a vent hole on the opposite side from the pump intake, about half way up the dip tube.

You can use two tanks. One for injection and the other for recovery. If you leave the recovery tank attached and open, while sitting in a dry ice bath, and have your flood tank in a warmer bath, you can have both pressure and vacuum to relieve the vapor.

The warmer injection tank can provide the pressure you need, and you can prechill the injection using a heat exchanger between the injection tank and the column. We use a counterflow heat exchanger and liquid N2, but have used dry ice and alcohol with 25' of 1/2 stainless tubing coiled in a bath.

Depending on the mix, limits on LPG temperature is how thick it gets and hard to push, so there is an inverse relationship between pressure and temperature. The colder you get, the more pressure you require to push it through the system.

At least one manufacturer uses N2 gas as a vapor head in the injection tank, to force the LPG through the column, and burps it off later.

 

[DjangoNugs]

Well my thoughts exactly. At least the part about having the solvent tank and recovery tank on opposite ends. I have the second 50lb tank coming in today so that's gonna be what we try next. We actually are using an active system with one tp21s. We have the mastercool condenser between pump and recovery tank. (Is that the same thing as a heat exchanger?) We have a 12" base (no liquid dipstick), with a 2x12" splatter platter, and using 5lb tubes currently. Sometimes 2lbs. No matter what size though we can Only fit between 30 to 50% of the gas needed in the tube. (Is that typical, with multiple short soaks? Or should I be able to get all the solvent in there, with one soak?) And it got more difficult to move the gas once it got cold out. The collection chamber kept freezing over and wouldn't fill up. The solvent would just sit in the tube and we'd have to leave the tube on for the recovery instead of being able to take it off and refill it while waiting. That is, until yesterday, I put the collection base in lukewarm water, like 80•, to keep it at room temp and from freezing. all the solvent fell right out of the tube, filling the base to its proper level, as soon as I did it. Seeing how we didn't have as much of a problem when temperatures here were in the 80s I'm assuming it's best for the base to be about room temp. Does this make sense to you? Just trying to get past all this speculation. And I read about a lot of people keeping their base in ice baths. Hopefully this will all be a lot easier when my new pressure gauge comes in Monday. I feel blind without it...

I've heard of this n2 blast to help things along as well as help yield but can't find any info on how to apply this. You've given me a few hints on the past on other threads that's helped my understanding a bit. Could you elaborate on how to apply it? if it's a whole other beast you don't have to go into it no worries. Just figured I'd lay out all my current questions in one place especially since you brought it up. Always grateful for any advice I can get.

 

[Xtractor81]

I'm having a problems getting liquid out of my tank. Normally I start with 9 lb. 4.5 holding and the other have on the chamber. A 3rd recovery of 4.5. Now I be lucky to get 7 lb and 2 lb max on my 3rd recovery. Why is that I have no pressure¿. I been getting my buttabe N in dry ice baths to do shatter. Now the days my ovens are full I'm just blasting for clear but my tank ( already out of the ice n at room temperature ) seems to have no pressure. ????

 

[Graywolf]

I'm having a problems getting liquid out of my tank. Normally I start with 9 lb. 4.5 holding and the other have on the chamber. A 3rd recovery of 4.5. Now I be lucky to get 7 lb and 2 lb max on my 3rd recovery. Why is that I have no pressure¿. I been getting my buttabe N in dry ice baths to do shatter. Now the days my ovens are full I'm just blasting for clear but my tank ( already out of the ice n at room temperature ) seems to have no pressure. ????

My guess is that you are chilling the LPG low enough that it has no pressure and doesn't flow well. I've had that occur on the last flood when I was using dry ice baths to chill the heat exchanger and recovery tank.

 

[Herb Forester]

Are any of you doing strictly passive with a propane blend? I gave up on it due to above issues, but only tried the simple dry-ice/alcohol bath. This thread made me think more. @Graywolf where can I find more details on that N2 heat exchanger?

 

[Graywolf]

I couldn't find 1/2" counterflow heat exchangers with a .049 wall thickness to meet ASME for LPG, so I had them wrapped by Albina Tubing in Tualatin, OR. I used a 1/2" X .049 304SS inner tube and a 3/4" outer.

I finished them myself using Swageloc custom tees, with 3/4 X 1/2 X 1/2 ports. I then drilled through the straight through 1/2" port so that the 1/2" tube would slide through it. That allows the end of the 3/4 leg to swage on one port and the 1/2" tube pass through the other port and be swaged along its length.

 

[Herb Forester]

I couldn't find 1/2" counterflow heat exchangers with a .049 wall thickness to meet ASME for LPG, so I had them wrapped by Albina Tubing in Tualatin, OR. I used a 1/2" X .049 304SS inner tube and a 3/4" outer.

I finished them myself using Swageloc custom tees, with 3/4 X 1/2 X 1/2 ports. I then drilled through the straight through 1/2" port so that the 1/2" tube would slide through it. That allows the end of the 3/4 leg to swage on one port and the 1/2" tube pass through the other port and be swaged along its length.

Thanks. How long are they? And how do you move the N2? Is it a liquid or gas as it enters the exchanger?

 

[Graywolf]

They are 20' each. The N2 enters one end as a liquid and exits the other a gas.

 

[Herb Forester]

They are 20' each. The N2 enters one end as a liquid and exits the other a gas.

How do you transfer the liquid? A pressure building tank with dip-tube? And how do you throttle the flow? Do you have any idea how much N2 you're using, to compare on a small scale? Sorry for my ignorance.

Fyi, my lil' Terp clone has a 2x36 column with 6x6 pot (no dip), a little mismatched I think.

 

[Graywolf]

How do you transfer the liquid? A pressure building tank with dip-tube? And how do you throttle the flow? Do you have any idea how much N2 you're using, to compare on a small scale? Sorry for my ignorance.

Fyi, my lil' Terp clone has a 2x36 column with 6x6 pot (no dip), a little mismatched I think.

We use a Dewar with a dip tube valve as well as a vapor valve.

I used a Swageloc valve on the discharge to throttle the flow, but you have to do it before much flow transpires, because it becomes inoperable fast.

You could also use a fixed orifice. You can never close it off completely, because of the pressures that can be reached when the liquid warms to gaseous state.

A Lil Terp doesn't need a dip tube, but that is a huge column for that size lower tank.

 

[Herb Forester]

We use a Dewar with a dip tube valve as well as a vapor valve.

I used a Swageloc valve on the discharge to throttle the flow, but you have to do it before much flow transpires, because it becomes inoperable fast.

You could also use a fixed orifice. You can never close it off completely, because of the pressures that can be reached when the liquid warms to gaseous state.

A Lil Terp doesn't need a dip tube, but that is a huge column for that size lower tank.

Thanks. I use about 1/2 to 1/3 of that column for a crumbled coffee-filter stack, so it's just the volume and pressure issue. I matched my working supply tank using calculations from one of the build threads on your blog.

Maybe I'll grab a couple smaller columns and reducer, what size would you say is the best match for the 6" pot? And do you think the dynamics of a longer/skinny column make a big difference for passive use? (mine has a single soak-valve before the pot lid) Not sure why I picked 2" to start, I notice as vendors developed this market it's not a common triclamp size, although I bought everything from Glacier.

 

[Graywolf]

The 6" X 6" spool works well with about a 1 1/2" X 24" column. Not quite enough volume for a 3 volume flood from a 36" column.

 

[Herb Forester]

The 6" X 6" spool works well with about a 1 1/2" X 24" column. Not quite enough volume for a 3 volume flood from a 36" column.

3x, roger that, explains everything. Not sure how I missed this all along :facepalm: Things get better!

It's just been for personal, and yield a low priority. All the legal hoops you pros jump through make my head spin, so some years ago I declined to delve in. Stuck to what I'm good at :jimlad:

 

[Trees999]

@Graywolf, hey buddy been following you for years not sure if your still engaged in this thread but I'll shoot anyway! I'm freezing my 1000 lb by water weight butane tank 70iso/30n butane to -28 c in a walk in freezer, the goal is to also freeze the 100lb material chamber loaded with fresh frozen or frozen trim to produce some pristine extract at a higher volume. Working on color by freezing water locking out chlorophyll and coagulating waxes in the material colum, and also preserving terpenes. I need pressure but have been told back filling with compressed nitrogen even regulated to a low pressure will cause a reaction inside the tank resulting in catastrophe, the other solution adding propane to the mix. Any ideas or solutions to get my very cold gas flowing?

 

[Graywolf]

@Graywolf, hey buddy been following you for years not sure if your still engaged in this thread but I'll shoot anyway! I'm freezing my 1000 lb by water weight butane tank 70iso/30n butane to -28 c in a walk in freezer, the goal is to also freeze the 100lb material chamber loaded with fresh frozen or frozen trim to produce some pristine extract at a higher volume. Working on color by freezing water locking out chlorophyll and coagulating waxes in the material colum, and also preserving terpenes. I need pressure but have been told back filling with compressed nitrogen even regulated to a low pressure will cause a reaction inside the tank resulting in catastrophe, the other solution adding propane to the mix. Any ideas or solutions to get my very cold gas flowing?

I suggest using a Butane/Propane mixture at that temperature. Here is some info on the subject: http://thealchemistresource.thealchemistresource.com/p/blog-page_29.html

I also advocate using an auxiliary hot vapor tank of the same mix if you need to boost it further.

Nitrogen works and it is inert, but you do have to remove it before a recovery system will work, because it is non-condenseable, and in so doing loose some gas, as well as a fire hazard if not carefully controlled.