Always ramp up heat slowly. If you heat your oil too much it can crystalize in the hose and or catch fire
This cleaning was from ~ 2 months of daily ramp up to 240C using Duratherm S. We actually had a Duratherm rep get us to buy the “G” once and it was way worse. G cracked right away and smoked like a tweeking hoe. That cleaning wasn’t fun. We still have around 2 gallons of G left.
Also wooks will try and mix the S and G together and destroy a grand in thermofluid (50L roto) real quick. “but the bottle looked the same” smfh.
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Why the fuck were u going to 240C?! nothing even short paths should need to go that hot
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Ive had the same 5 gallons of duratherm s in the roto for a long time now a no corrosion. Bought 20 gallons 7 yrs ago and am still using it, it was dirt cheap then before they knew people in cannabis were using it
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We run up to 240C all shift long. I’m also not at liberty to say why we do this. We’ve run this way for the last 3 years though.
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We import Jarytherm DBT in drums. Pour down into 5 gallon pails too. It’s good to 350C, but that’s probably overkill for extraction
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What’s it made out of? Silicone?
I’m an overkill kind of guy. I like the look of those fluids. Thanks for the tip!
DBT stands for dibenzyltoluene.
Sounds like an awful, angry molecule, but ships as non-hazardous material. We repackage in house
We’ve used DOW XIAMETER PMX-200, 50cst Silicone Fluid on our YH Chem wiped film units for years. Works great. If you have a glass unit it’s really great because it doesn’t get dark when heated and block your process view. It’s back ordered like crazy right now, but I ordered a couple barrels when I found out there was a shortage. They should arrive next week and I’ll have it in stock.
Did you get any yellowing/darkening with the Caldera 7?
I’m torn between 5gal of Duratherm S or Caldera 7.
I’m looking to run the fluid in an open bath at temps of -40C to ~120C, I wont be running at 120C too often. I’d like to be able to see whats going on in the reactors without the yellow if possible, do both fluids come water clear at the start?
I have duratherm that was only used in open bath decarbing in a roto and its about 7yrs old and no discoloration
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Hey there, I’m Mike, Duratherm’s tech director. I realize this is an old thread but a customer directed me to it and i thought I’d come on and clear up a few things.
The bath systems used in extraction are a challenge for thermal fluids due to the high rate of oxidation. Most fluids will not hold up for long. For example, we have mineral oil based fluids, stuffed with anti-oxidants that can last for decades in larger closed systems but in a bath, the life would be mere hours.
This is where silicone oils shine. They’re all a little different, have differing temp thresholds but for the most part are impervious to oxidation. They are certainly expensive but given the application in open baths, do offer the best value in the long term.
Our Duratherm S’s ‘oxidation’ threshold is 204C which aligns well with most of what you’re all doing in the extraction industry. However, what happens if you heat it above that, if even for a short time, is that it triggers a polymerization process. The higher the temp the faster the process happens but eventually the fluid will thicken and then flip into a gel state - similar to a semi-cured silicone caulking.
We do offer other bath fluids, as mentioned here, our Duratherm G is another, more economical option. The biggest differences are service life and color.
It won’t last as long as Duratherm S, it’s 1/3rd the cost but I feel Dura S has more than 3 times the life. The biggest difference though is clarity, Dura S, and most silicone fluids will stay clear throughout their life. Dura G will darken pretty quickly. Fine if you’re using stainless but if you want to see through glassware, Dura S is the way to go.
Another consideration is ventilation. Under 200C Dura S has no off gassing/vapors/smoking, whatever you want to call it but Dura G does and requires good ventilation – the fumes should NOT be breathed in. Mineral oils are worse!
I’d like to directly comment on a few of the comments in the thread as well.
@PrinetuckyPhase – I’m pretty sure what you had there was our Dura G in those pics, not Dura S. If it were Dura S at 240C you’d have turned it to a clear gel. Dura G at that temp is not particularly recommended either. It’s workable but will have a short life and needs to be monitored to avoid what you had happen. My apologies that it did and if you bought directly from us and you weren’t informed, , that’s on us.
It’s also worth noting that the watt density of the heating elements in the bath system is important, it’s not the wattage output, it’s the watts per inch squared. For Dura G we don’t like to see more then 12 w/in2, which works for the most part but a few bath systems have watt densities in the 30+ w/in2 range. This if fine for Dura S but will destroy Dura G very quickly.
I’m curious why you’re looking for 240C but if you really need to go that high, have a look at phenyl methyl based silicones. Dura S is a poly dimethyl; phenyl methyl’s are a LOT more expensive but can handle that temp.
@ greenbuggy – it’s not the mineral oil itself that causes corrosion but when it oxidizes, which is does very rapidly in a bath, it forms acids. Normally a very mild carboxylic acid but enough of it can get corrosive. Another reason why mineral oils are just not suitable. Well perhaps if you’re running under 50C, maybe.
@ GasGuy-QEG– yes DBT based fluids are another option. DBT or dibenzyl toluene holds up well to oxidation. You don’t need to import Jerrytherm though, look at Marlotherm SH. It’s offered by some of the bath manufacturers as a cheaper alternative to silicones, but I can say a lot of users come to us for Dura S after trying it. It also turns dark so not great for seeing through glassware but also requires good ventilation and can start to smell pretty bad after use.
I don’t want to post links or appear to be promoting our fluids but feel free to reach out directly if you’d like to chat – we’re not hard to find.
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Welcome to the future Mike! That’s some excellent info on heat transfer fluids, and we really appreciate you sharing.
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