A buddy of mine sent me this link: https://solvent-recycler.com/ for a solvent recycling machine. Basically it’s a still with a refrigerator unit to cool the vapor and collect clean IPA. Single-button operation. Just dump in the dirty solvent, seal the lid, hit a button and come back later to retrieve the fresh IPA and remove the plastic bag full of resin (which could be put in the sun to cure and then dispose).
This manufacturer quoted me around $3800 for the unit. There are other manufacturers of such machines but I have not found a better price for the capacity. It’s a mature technology that has found application in various industries that use solvents such as automotive painting.
Thinking about recycling the IPA, instead of using and disposing of it, which is a pain. For the amount of IPA we use I am thinking the machine would pay for itself fairly quickly.
A bonus could be having fresh IPA for each form-wash load instead of running it until it gets dirty enough to change out.
Would such a machine work for recycling TPM or DPM, I wonder. Darnit Jim I’m an engineer not a chemist. Any chemists feel free to chime in.
I believe that there are solvent degreasing or cleaning machines that have a heated sump to hold the solvent. The evaporated solvent rises into the upper section, condenses, and then drips over the item to be cleaned and drains back into the sump. That might be an interesting approach to cleaned resin parts so long as the solvent gets into all the nooks and crannies.
So far as TPM and DPM go, a search for their vapor pressures and boiling points and comparing that data to IPA might be instructive. Probably best to just call the solvent recycling machine maker and ask them.
I have 2 home stills that I use to recycle IPA. I just run one at a time. Only cost $100 on eBay and work great. I do have a large barrel type container for water that is recirculated to cool the IPA. I can do about a gallon and a half an hour.
Never have had the plastic bags work in the still. As they get burnt to the bottom and break of course. I used the baking bags that are supposed to take 400+ degrees. So, I have to do a bit of scraping but it’s cheaper than disposal through a service.
There’s little to no explosion threat. Keep the temperature to just the level that it produces output. I use a digital electric heater that I set the wattage on and that does it. I’ve been doing this for over 3 years with no issues.
I run it on a screen porch at the back of the house or sometimes in the garage. Keeping the water tank cool is the biggest issue but so far that hasn’t cause any problems. I’ve distilled maybe 200 gallons of IPA this way.
Look up azeotrope and isoproyl alcohol - you should 91% IPA in your distillate assuming that it was saturated with moisture to begin with. You can get a drier IPA if you run your distillate through a molecular sieve. The mol sieve will need to be regenerated periodically to remove the moisture that has been absorbed.
I’m interested in learning more specifics about your setup. I know nothing about distilling, but I went on amazon and found a few wine distillers in the $100-150 range and now I have even more questions…
If you don’t mind-
You mentioned plastic bags not working. Do you pour the dirty IPA into a bag inside the heated pot? Not just straight in?
Does your system have the intermediary cooling pot? The “thumper”?
You mention using an electric digital heater. Is this one of those college hot plate sort of deals? or more robust?
Thanks in advance. I can’t believe how fast this stuff gets dirty…
No, I’ve even use Oven Bags and they still get burnt to the bottom of the pot. Best to not cook the dirty resin down so it burns. Scrape it out after 2 or three fills. There maybe still some burning but it won’t be real bad.
No, you can see int he photos it only has the one condensing pot. That’s all it needs.
I use a Rosewill digital hot plate with the wattage setting and 1200 watt level. Works well for me.
The big problem for me to use the cheap still is no idea when shall I stop the heating. Since every time I pour around 3-4 gallon alcohol into the bucket and let it run. Sometimes, I may miss the time and the machine keep burning the remaining resin and you will get those bad smell yellow liquid into your fresh-baked alcohol. This is frustrating and I just waste a few hours of time plus a bucket of alcohol since even you distill again you can’t get rid of the yellowish tint and smell.
I was looking for the same professional recycle machine too. Wonder anyone here gets some feedback.