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  • DE Filtration Woes

    Hey guys,

    We just started using a 3m^2 Velo Export DE filter (vertical leaves) a few weeks ago. I've filtered one 60bbl batch with it so far, and it was sort of a disaster. We had to break the filter down twice during the course of the filtration because the filter kept getting clogged. I tried filtering another 60bbl batch yesterday, but I gave up after spending 3 hours filtering about 5bbl.

    Things would start out ok - the flows we had in the first 5-10 minutes were pretty good. The filter manual suggests that we should aim for 20 hectoliters (~17bbls) of beer per hour, and we've tried to maintain that flow rate (as measured by a sanitary flowmeter we have going into the BT). But within 30 minutes or so, the pressure in the filter chamber starts gradually rising until I have to throttle down the pump so much that the flow slows to barely a trickle. I'm hoping some people with experience can take a look at our process and let me know if I'm doing something wrong.

    Here is the process we've been using:

    -Run a caustic cycle through every nook and cranny of the filter
    -Rinse the entire filter, and then run sanitizer through every nook and cranny
    -Drain the filter of sanitizer, and purge out remaining sanitizer with CO2
    -Purge out the O2 in the filter chamber with CO2, bleeding off some CO2 through the top valve in order to send a blanket of CO2 into the slurry chamber
    -Gravity feed cold beer (usually 32-34 degrees) into the filter chamber until it's completely full (it's pretty obvious when the chamber is full - there is condensation almost immediately on the outside of the chamber)
    -Fill slurry chamber with beer just to the top of the agitator (this is about 1/3 of the slurry chamber)
    -Add 5 lbs of Perlite 27M to the slurry chamber and allow to thoroughly mix with the beer (the manual indicates that we should use 4.5 kg of DE, I'm adding roughly half that weight in Perlite)
    -Precoat filter leaves and recirculate until the beer runs clear (this only takes like 3-4 minutes, which is encouraging because I feel like we're at least getting precoat right!)
    -Recirculate the filtered beer while loading the slurry tank with beer (to the top) and 15 lbs of Perlite 27M; mix well (slurry tank is completely isolated during this step)
    -Begin filtering beer at a rate of around 20 hectoliters (~17bbls)/hr
    -Open the dosing pump wheel fully in the beginning of filtration; back it down when the incoming beer is a bit clearer

    At the beginning of filtration, the pressure gauge reads around .5 bar. After about 30 minutes, however, it starts going up - not rapidly, but steadily. It gets to around 3-4 bar within 10-20 minutes if I don't throttle down the valve after the filter pump. I can only get about 2-3 bbls filtered before the pressure gauge hits 5 bar and the flow decreases to a trickle. When I broke down the filter yesterday, I removed the leaves to examine the caking. There was definitely a thicker cake at the bottom of the leaves, and I'm not sure how to correct this to get more even caking.

    I should also mention that the beer I tried to filter yesterday had been cold crashing at 32-34F for 7 days prior to filtration. And, I cropped off all of the yeast (San Fran lager) prior to starting filtration from the racking arm. So, it was fairly clear going into the filter.

    Any suggestions on where I'm going wrong? I have to believe that this filter is capable of a greater throughput rate than what we've been getting.

    Cheers,
    Matt
    Last edited by Matt@Bauhaus; 08-31-2014, 09:10 AM.

  • #2
    These are tricky to run and a good operator will do things differently than another good operator. You would be best served by spending time in a brewery with a good operator and learning some of their tricks; or have them come to you. Short of that, it's tough to suggest many things remotely without being hands-on. Do you have an erosion type filter as opposed to a pumped dose filter? You mentioned pump, but maybe it's a valve? I do have a few suggestions: Push the sanitizer out of the entire filter with CO2; do not let it simply drain allowing oxygen into the filter. If you push with CO2, your filter won't have to be purged subsequently. Although many folks do it with good luck (including me most times), it may be helpful to precoat with clean water. Clean, deoxygentated water makes a superior precoat. How much body feed is going to the first beer through the filter? Or how much body feed is left in the tank after you plug your filter? And what is the thickness of your cake after you plug? It may make sense to dose as much as possible in the beginning and taper back the body feed later. Sounds like your initial bit of beer yeast is binding the filter. Dose much more in the beginning and learn where the sweet spot is. Once you get the beer running through the filter at a good rate, you may be able to body feed the last 20-40% of the beer at just about zero before the pressure rises to full. The filter is harder to plug the more filter cake you have. The increased depth of the cake, plus the reduced yeast loading of the last beer through make it possible to have nearly no body feed through the last of your beer. I use nearly all my body feed in the first 60-80% of the run. You could also slow down the flow rate of the first beer to build your cake without excess yeast binding it. Maybe run at half speed until you have built some thickness. Keep trying--there's light at the end of that tunnel! Good luck!
    Phillip Kelm--Palau Brewing Company Manager--

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    • #3
      I'm just getting my nose around our one after using plate and frames for years, outs has 17 frigging valves on it. But, i have a boy wonder who runs it real well now.

      Is the beer carbonated? We were capping back in the FV, but we found the beer foamed out on recirc after the bed was formed and it caused hell(disrupted the bed).

      After that issue, we found best forming the bed with the sanitiser fluid (peracetic acid) then purging out with C02, bringing the beer thru afterwards.

      We have a higher take off point, so run from there too, then switch to the tank bottom.

      But i agree, borrow a mate who knows how to run one for a few goes ...
      Head Brewer Rocks Brewing Co.
      Sydney, Aust
      scotty@rocksbrewing.com

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      • #4
        Thanks for the feedback! I have been looking for someone in our area to come out and help me troubleshoot our filter. I agree that having someone physically present to share tips, tricks and experience would be ideal.

        Regarding deaerated water, how does one do this without sophisticated deaearation equipment? Bubble CO2 through brewing liquor? Boil brewing liquor and send through the HX?

        Also, if we wanted to use sanitized water for precoat, what concentration of peracetic would be advisable?

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        • #5
          Boil the water. Not sure how practical is this.

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          • #6
            Deaerated water...

            There are other more comprehensive threads on deaerated water generation here. Suffice to say that boiling and bubbling CO2 is one common way in many breweries. I would not use PAA water to precoat--even if I used PAA for sanitation. I use chlorine dioxide and don't even use a dilute chlorine dioxide solution to precoat. I can get away with a dirty beer precoat because our DE filter is way larger than we need. In situations where that hasn't been practical, it's clean & deaerated water.
            Phillip Kelm--Palau Brewing Company Manager--

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            • #7
              Just wanted to follow up on this thread with some progress notes. I tried changing a few things in my filtering process with today's filtration, and I'm happy to report that I was able to filter 60bbls of Oktoberfest in a reasonable amount of time without having to break down the filter! For anyone who's interested, the things that I changed are as follows:

              1) I fined with biofine in the fermenter and really made sure to give the beer an adequate fining period (3 days @ 32F, in this case) before cropping off the coagulated solids. This resulted in a much less turbid beer going into the filter. I suspect this may have had the greatest impact on the beer's filterability.

              2) I did two precoats with Perlite 23S. I still did these precoats with dirty beer, but it was far less "dirty" than previous filtrations. Also, I used less Perlite for these precoats. After speaking with another brewer who uses the same filter, I tried just adding Perlite by "feel" instead of actually weighing it. Using this brewer's general guidelines for precoating with Perlite, I got really nice precoats.

              2a) I used Perlite 27M for bodyfeed. Not really sure if this had a significant impact, but it certainly didn't hinder the filterability.

              3) I started really slow -- like, 8 gal/min. Once things were dialed in and I had a nice filtration going, I increased the speed slightly, but I still kept it pretty slow throughout. It took about 5 - 5.5 hours to filter 60 bbls, and I'm happy with that given that our filter only has a 3m^2 bell.

              Cheers,
              Matt

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              • #8
                Good to hear.

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