Flow not right

Been running this new system for about a month now, it’s a passive 30lb unit with 4 material columns. the flow is starting to take quite a bit longer (20-40min) and now have to open recovery valve and keep collection vessel at negative psi to keep consistent flow or else it just shower/spurts alot slower into collection as where before it would be a steady stream. I recently changed my solvent from 70/30 to straight n-tane and did a clean in place run straight from bottom manifold to collection and didn’t include the crc think that would fix the problem and it didn’t. So tomorrow with my CRC column attached I was planning and doing a full run with no material or media to see if that cleans all the manifolds and crc column correctly, also most of the bottom manifold I see frosting and flowing correctly it’s up till the line going into the CRC starts to go from frost to thawing which is a sign that it’s not flowing correctly. So I plan on doing that unless anyone could guess what all of a sudden is making my bypass take so long

Not a lot of info present…could be cold and there’s no pressure, if it’s not just the crc…
Do you push with nitrogen?
Can you paint a better pic of what’s happening? How much material? How much solvent? How much solvent does your tank hold???

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Yes I push with no2 at about 30 psi no higher than 60. And 30lb of material per run with 3-1 solvent ratio. All gauges are at the right psi during run and also temps are correct throughout

I believe it’s a clog of some sort in my line going from my bottom manifold going into my crc column but I cleaned the line good and it was no clog and the psi on my crc is same as my material column but drop down to collection to solvent obvi (passive)

What size is your crc?
Powder or granular?

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I use about 135g of in order activated alumina, t5, silica60. Filters on bottom of column go from 5,1, .2 micron

Size of it I don’t exactly know it’s about half the size of 1 material column so maybe like a pound

Lol, so 6” wide?


What’s the spool size for example 4”x12”?
I’m asking because depth can help determine how much psi is needed however it sounds like you’re running cold into the powders. The reason it might not have done it in the past could be because the material was older or low in thca. When it’s fresher material it will be higher in thca and running cold into the crc powders can cause some of that thca to crash out as a “pulp” on top of the powders and cause it to lose its flow


Lol sounds about right

How tall is the crc? 135g of 3 medias is still a very small cake depth in a 6” crc. I don’t think that would clog it

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I will have to check for exact sizes sizes of crc tomorrow. Been running this lab for about a month now and took it over from someone who was way smarter than me lol but I’ve been doing good so far and just trying to get better. I’m planning on going to San Diego end of month for your seminar, I’m working up in central coast area now so not bad drive. But yes solvent is very cold -28 going into crc column

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When you run solvent that cold while carrying thca/oil through a smaller micron it will start to drop out the thca like this pic here. In the pic I had no media it was just a sintered disc and it still clogs it so the same effect is happening on top of the crc powders when you run cold solvent into it. If you use a coil to preheat the solution it will prevent the clogging and improve your bleaching results.


I usually soak material 5-10min in the chilled material columns and it’s goes through bottom manifold lines straight to crc, so a warm coil before crc would prevent media from basically hardening up? Lol idk if I could even set that up


Is the alumina you’re using granular? Are you layering it as the top layer? You could also jacket the crc but then you would require quick connects to disconnect when you reset the powders or use a cartridge style crc


When I took apart the crc it was all pretty much spotless, everything under the paper filter at least I mean the column walls were obviously dirty

Yes granular style, we use it at the bottom for better flow

Try using a layer on top or another granule like UltraClear. Granulars usually warm up in the very beginning and that’s enough to prevent the clogging when running cold


I’ll try it on top tmrw.



hey worked really nice! did about 10 runs since I switched up the media and only had a slow flow on 1 run and I think it was because i didn’t throttle the valve correctly and solvent shot in to fast? also wondering if it wasnt happening weeks prior since I was using 70/30 and if pure n-tane runs colder than 70/30 propane mix

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