Hey Guys, Coming here looking for some tips anyone may have for improving my short path distillation process.
I currently am working with a start up in a medical state and so its kinda been learn as I go with little to no training. I have just started with distillation of our CO2 crude in the last two weeks and its going well. I haven’t had any real training and have been just teaching myself from online information I can find. My first run at it, did two passes and got a 80% potency and wasn’t really happy with that as it came out a amber color and I not what I was looking for. I refined a few techniques and got my vacuum lower and my last batch done at two passes came back at 90% THC. I am pretty happy with this but still want to do better. The 90% has a red layer at the top that I cant seem to get rid of.
Right now my vacuum is sitting around 700-1000 microns and I am struggling to get it any lower and cant find the leaks for the life of me. Any tips on improving my vacuum would be greatly appreciated. I am sitting with my mantle temp around 200 for the body pull and my head temp is sitting around 175-180 C. I want to get this a bit lower and assume the issue is coming from the vacuum but I am not entirely sure.
I am also seeing a red substance appear as the distillation occurs over time in the head and as I said before I am getting the red layer at the top of the distillate. maybe oxidation but I’m really just guessing at that. In my test results I am seeing almost 3% CBG and I am not sure why and at what temp I am pulling that at and would like to reduce it if possible.
Any tips or information would be greatly appreciated for this! thanks in advance!!!
Defiantly sounds like a vacuum leak, first pass should be 300 microns or lower, second pass should be under 50. What is your blank off vacuum depth? What is the vacuum depth with your system dry? How big is your still?what vacuum pump do you have? What temp are you taking your mains at? Try using a helium tank to check for leaks, as I’m pretty sure you have some.
We had the same problem. Our vacuum wasn’t large enough for our system. Make sure you have at least 4 CFM per liter of crude. If your vacuum can pull way lower on a blank this is likely your issue.
I am currently running on a 2L setup and running about 600-900ml at a time. Im using a Duoseal 1400 welch vacuum. With it blanked off I am getting 100-300 microns which lead me to think its a leak. I was hoping to get my head to pull around 158-160C on my 2nd as I have read thats a desired temp to pull just my thc-9. Though I am not sure if I am aiming for the right temp or not to be honest but the 90% tells me I am at least in the right direction for now.
Due to my lack of experience I am a bit unsure of how to check the vacuum on a dry system(I assume just with the distillation setup and no crude?) and also unsure of how to check for leaks with helium but I will do some reading on it and see what I can come up with!
And the way I check for leaks is I stare at my gauge while a push two pieces towards each other while I rotate the joint. Do this to your distillation head by rotating the entire arm. If it goes down even a smidge rotate that joint until it doesn’t do down any more.
Your blanked off depth should be much lower. How often are you changing the oil? Are you running wide bore or gls? Can your post a picture of your system?
I am using mobil vacuum pump oil. Its unfortunate not what the manufacturer calls for but due to the nature of the startup its been difficult getting the proper tools so i am just working with what i have until I can get what I need. I am reading my vacuum is only capable of 0.9 CFM. Could this be the reason its taking me 4-5 hours to distill 600ml? The length of my runs seems to be a bit long from what I have been reading.
Also a picture would definitely help. A higher CFM pump could definitely speed up your runs if the issue isn’t just a leak. If you can swing it (and if you need it) get a full bore conversion kit for your set up.
How are you cleaning your joints before assembly? Also, in before anyone else, maybe poor quality glass? I try not to say “China” glass anymore as folks like @david seem to be working to end that stereotype, but poor quality glass will drive you nuts trying to pin down a leak.
Also, the 1400 is only .9 CFM?!? Shiitttt, and here I was just staying away from that pump because it was ugly. It also has a proprietary oil requirement, no?
So i actually have a KF 25 but its sitting under the table cause I wasn’t sure what it was for. Joys of no training Lol I am gonna see if I can get it connected tomorrow.
You should change oil with every run. Dump it, fill it half way, run it with the ballast open for 30 minutes, dump it again. Repeat until it comes out clear with no smell then fill it up. Change it after your run it not before. The sooner you get those volatiles out of your pump the better.
Agree with @Schwarzite and @Rowan. A bellows to the pump will make a big difference. Also, when was the last time that thermocouple gauge was calibrated? Every 6 months is key, especially if running on the hot side.
Using soap and a scrubber to get the grease off, then hitting all of it with a shit ton of Iso. Hoping the acid/base bath I requested comes in next week.
Skip the iso and soap. Use acetone to clean your joints before using grease. Also, use acetone in the Dewar trap for thermal transfer. Works way better than ethanol or iso. If you can spring for it grab some Apiezon 501 grease. Dow is garbage.
