[Itsgotatail]

I'm looking for an affordable way to set my CLS up for live resin. I'm seeing high pressure counterflow plate heat exchangers for under $100. Thinking about just plumbing one up to a 5000 BTU air conditioner and running my butane through it before entering my material column. Since I'm working outdoors and it's not getting above 40°F while I'm working (nights in Oregon), I'm thinking that I can get away without column chilling for right now if I can get the column injection temperature low enough. I'd like to just keep my reservoir tank and the chilling coil between the recovery pump and reservoir tank sitting in regular ice to keep consumable costs down. I'll plumb them into another (or the same) AC unit later to chill them down to ~0°F later on, with glycol, to speed things up.

So the question is: using a 4"x48" material column, and with the material and column at 40°F, how cold do I need to get that injection butane in order to avoid picking up much waxes? Will 0°F cut it, passing 2 volumes of solvent over the material (bi-flow, one volume up, another down). I know GrayWolf recommends 3 volumes of butane but I think he was talking about everything being at -40°F, which should take more solvent for the same yield. Currently, running everything at 40°F, just 1.5 volumes of butane seems to be enough to pull almost all of the good stuff out.

[Itsgotatail]

Here's some pics of my in-progress rebuild, where I've reduced the system from two material columns to one, so that the system can be more compact and portable and doesn't require the 800lb gigantic chassis that came with it. Plus that second column really doesn't save me any time since it takes twice as much solvent and it's recovery is what takes up almost all of the time. Seems easier to do 5-6 single columns per day than 2-3 doubles. The material column isn't mounted in these pics (it doesn't fit inside with 8ft ceilings!). This looks kinda wonky with things in weird positions but I did this all without having to disassemble ANY of the 30+ NPT fittings, only the triclamp stuff. I did this because the NPT fittings are difficult to get just right, with PTFE tape and all. And I only had to buy like 4-5 little connectors (<$30). And because of this, I've managed to hold a vacuum on it for 12 hours+ on the very first assembly! Hydrocarbon sniffer test tomorrow. I wanted to do it as cheaply and easily as possible. I'm quite pleased so far. Somehow, even with everything crossing through each other, all of the valves can still turn easily. I've reduced the total system from about 6'x4'x9' tall to about 3'x3'x4' tall with just the single material column sticking up higher, and shed about 1000lb. Now, alone, I can break it down and fit it all in the CAB of my truck, when before, it took an engine hoist just to get it in and out of the bed of the truck.

[Itsgotatail]

And if 0°F is not a cold enough injection temperature, how cold can I get it using a window-unit AC? Is there a refrigerant that could be put into a regular AC unit that you would recommend for reaching say, -40°F? Would a 50-plate, 4"x12", 350000BTU/hr heat exchanger be big enough to get that butane down from 32°F to -40°F in one pass through? I suppose that depends on how fast the butane is flowing...but if I want to push 20L through it in 10 minutes or so?

[WaterFarmFan]

I am not sure about the other stuff, but I do have some experience with gas and those plate exchangers. Take a look here - https://www.icmag.com/ic/showthread.php?t=347197&page=3. Your application is very different, but I saw a huge difference in efficiency going from coil to plate. The irregular pattern within the plates creates significant heat exchange.

What PSI would the butane be at? I found lower psi helped increase contact within plates and produces better exchange.

[WaterFarmFan]

There are so many variables that influence residence time that is very difficult to calculate the exchange rate. I would recommend to do as I did in the thread above and use both sides of the exchanger by cross connecting, and then chill the entire unit with dry ice bath. You could simply keep adding more exchangers in parallel if needed. If you want -40C in a single pass, then if using a -40C bath your residence time will need to be the maximum, but if your bath is -78C, then your residence time would need to be less, as the delta temp change is greater. Like me, you will likely just have to buy one and experiment, and in this case biggest (# of plates of the longest length) is most definitely better, but you have to think about the shape of your bath and its efficiency over long periods if required.