Propane Vapor Assist

I'm currently running an MKIVc passively and have only done crude oil batches at this point in time. I am on the verge of doing my first pass at -20F with a 70/30 butane/propane mixture. I am wondering if the propane in the mix will have enough vapor pressure to push the liquid gas through the material column and into the collection pot without having to use an extra tank with warm gas for assistance? From my understanding propane should have about 11 psi at -20F with an ambient temperature of 80F.

What temp does the gas turn to vapor...if it doesnt pass thru try vaccuming down ur system and recovery tank. Make sure material is dry to prevent ice blocks

-43.6F is the boiling point of propane. My system will be vaccumed down, I am talking about using my solvent tank as my recovery tank as well. I've heard most people using 3 tanks for a passive system. One for vapor assist, another for solvent tank, and the last for recovery. I could pull a vacuum on the recovery/solvent tank after I have injected the hydrocarbon mixture as long as I can inject the remaining amount of gas that's in it. I will be using all of the 12 lbs of gas that's left in the tank to wash through a 4x24 column, which should be approximately 2.5 lbs of material. Would rather not ruin this batch over experimentation as it is some prime material belonging to a friend. Thanks for the response @dabbindylan

I will eventually be getting an extra tank for recovery, and plumbing a tee to my solvent tank vapor port for future vapor assistance use. I figure I can use the tank from refinedhydrocarbons for the vapor assist. It is just a single valve with a dip tube. Maybe I could use this to pull a vacuum on for assisting in the meantime. Might even just pick up 100% propane next time for the matter.

@Fadedawg maybe you could chime in? It would be much appreciated.

My only concern is that if the propane vapor travels through the liquid LPG rather than to keep pushing on it, that the pressure will equalize and I will only be able to get a few lbs of liquid injected into the column if none at all. Which I feel like I have heard of happening to others before.. I know the MKIVc is designed to run dual trs-21's and maybe this is the reason why?

I would plan on a vapor assist at -20F. That is about the limits of a pumped system at that temperature.

Research the difference between gases. If your going to switch from iso butane to propane. Temperature will lower pressure and the gas should condense in ur collection quickly.

Fadedawg said:

I would plan on a vapor assist at -20F. That is about the limits of a pumped system at that temperature.

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Thanks for the suggestion.