Bag Filters for Ethanol Extraction

Does anyone have a lot of experience using bag filters post centrifuge? We are running -40c in centrifuge and solvent tank so hoping lipids won’t pull at that temp. Just trying to get majority of particles out before the 12" Lenticular AC filter. We have two #4 bag filter housings, I was thinking 10um and 1um?

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I like to start at 25um and then stage down to 10um. I have had good luck. We also utilize pre injection coils to make sure we are staying -40c. If you think you lose a few degrees wouldnt hurt to put like a 5um filter at the end. You may run into it filitering slowly at the 1um. We also run massive amounts so we swap our filters out alot. 10um to 1um is a really good start to see if it works for your system. You are on the right track!.

I found lining the fuge with 1um felt made secondary filtration essentially superfluous…depends on your scale how applicable that is.


Hmm that’s interesting…
Lining the outside of the inner basket or the inner of the surrounding drum? Are you talking about a bag? How would you attach this lining. TBH I love the idea of secondary filtration being superfluous.

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A lining on the inside of the drum. If u cut the right size and stitch it together, it should hold in place with centrifugal force. Once u run it a couple of times, it will almost glue to your drum. Only need to replace it when flow starts to slow down.

I setup a stacked system, so 50 micon felt closest to the bio and ended up with a 1 micron felt closest to the drum. There was 50,25,10,5 and 1 in there. Alittle overkill but i ran it for about half a year b4 having to replace it. Just took the 50 and 25 micron out periodically to rinse it (inside out).

After setting up the “prefilter” in the centrifuge, i think we only replaced our secondary filter skid once or twice per year.



You still have stuff that misses the bag, and every now and then bags let go.

Hey all! Little late posting here, but if any of you need any bag filters or lenticular filters, give me a call or text. I work for Ertel Alsop, so we manufacture lenticular filters here in Kingston, NY, and we have partners in the States for bags and cartridges etc… 8457069140. Happy to give you my opinion on your filter system, and if you’re open to it, see if we offer any equivalents to save you cash, or improve your filter system’s throughput.

Regarding the filtration process discussed above; staging down is definitely the way to go, but only as much staging down as you need to prevent clogging of a bag. Another high efficiency filter with tight retention and more depth, or with a filter aid added, (like a lenticular) might retain some more waxes than a bag, and provide more throughput, but if you’re not having downstream issues or throughput issues, then don’t fix what isn’t broke!

10um and 1um could work as far as staging if your batches are small enough. #4 bag filters are pretty small for most peoples’ volumes in my experience, but may work fine for you!