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Thread: Recirculating Municipal Water for Distillation Condenser

  1. #1
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    Recirculating Municipal Water for Distillation Condenser

    Is anybody using some sort of heat exchanger to circulate distillation cooling water for their condensers? We use anywhere from 150-250 BBLs of city water for our cooling condensers on our 4 different pot stills. I want to took into somehow making this a closed loop system without a lot of space. Right now, we push the cooling water to our HLT which can be heated by steam. We don't mind heating the water up to our 170 F setpoint, since it is much cheaper than dumping the water. Does anybody have any experience using a glycol heat exchanger to recirculate a days worth of cooling water supply for stills? We have a jacketed 1100 gallon tank we could use as the reservoir. We have a glycol supply line within 10 feet that we could pipe up to a heat exchanger, but I don't want to cooling water to get too cool. 60 F is the ideal temp to run for our condensers.

    Anybody have any ideas or experience?

    Thanks,

    Derek

    Anchor Brewing and Distilling

  2. #2
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    It wasn't for a pot still, but I've used cheap cooling towers for just this purpose. Doesn't work everywhere, though. I set one up in San Luis Obispo, which is a bit warmer and dryer than SF, but not extremely so.

    It's basically just a round fiberglass container, open around the waist, with a fan that blows air out the top. You put a sump pump in there, or alonside, to circulate the water to your process. The fan turns on when the water goes above setpoint, and a small recirculating pump moves water from the sump to the top of a set of corrugated plastic panels between the fan and the opening at the waist. Evaporative cooling takes place.

    You might not get it to 60F year round, but if not, you can augment with glycol chilling using a small counterflow heat exchanger. It does consume water, and needs to be flushed periodically.

    Here's a picture of one (just google fiberglass cooling tower):

    http://www.ebay.com/itm/like/2919635...&ul_noapp=true

    I think the one I used was less than $2k. But it's been a lot of years, and I don't remember exactly. Pretty cheap to operate, though.

  3. #3
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    Quote Originally Posted by rdcpro View Post
    It wasn't for a pot still, but I've used cheap cooling towers for just this purpose. Doesn't work everywhere, though. I set one up in San Luis Obispo, which is a bit warmer and dryer than SF, but not extremely so.

    It's basically just a round fiberglass container, open around the waist, with a fan that blows air out the top. You put a sump pump in there, or alonside, to circulate the water to your process. The fan turns on when the water goes above setpoint, and a small recirculating pump moves water from the sump to the top of a set of corrugated plastic panels between the fan and the opening at the waist. Evaporative cooling takes place.

    You might not get it to 60F year round, but if not, you can augment with glycol chilling using a small counterflow heat exchanger. It does consume water, and needs to be flushed periodically.

    Here's a picture of one (just google fiberglass cooling tower):

    http://www.ebay.com/itm/like/2919635...&ul_noapp=true

    I think the one I used was less than $2k. But it's been a lot of years, and I don't remember exactly. Pretty cheap to operate, though.
    How often did you change out the water in the container? Or did you treat the cooling tower water? Since we run the stills 6 times per week, it seems I would still have to change out the water frequently to prevent corrosion and legionnaires' disease. I would rather not have an open loop cooling system and somehow make a closed loop system but I am not sure if that is possible within our limitations.

  4. #4
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    We use a 10hp glycol chiller from Whaley to chill our still in addition to cooling 3 fermenters (6bbl to 30 bbl) and the system keeps up with room to spare. Knocking out is a different story, wished we'd saved for a CLT... My experience is that the amount of cooling necessary to condense is pretty minimal.

  5. #5
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    Quote Originally Posted by fstmatt View Post
    We use a 10hp glycol chiller from Whaley to chill our still in addition to cooling 3 fermenters (6bbl to 30 bbl) and the system keeps up with room to spare. Knocking out is a different story, wished we'd saved for a CLT... My experience is that the amount of cooling necessary to condense is pretty minimal.
    Yea it doesn't take much to condense on our stills, but with the quantity we distill everyday I just want to find a better solution than constantly using city water. While we do recapture this into our HLT for our brewing side, it seems overkill using city water Theinstead of using some type of closed loop cooling cycle for the distillery. The thing I am having most trouble with is finding another cooling medium that can run through the condenser without worrying about contamination. We have had a pinhole leak in our condenser before, but since we were running city water, it was not a huge deal.

    Recapturing the condenser water which is roughly, 90 degrees F, and possibly cooling this to be reused seems like the best alternative. As long as the reservoir is large enough, the condenser return water won't change the bulk CLT temperature.

    Just trying to brainstorm, thank you for your comments and suggestions.

  6. #6
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    Quote Originally Posted by dleong View Post
    How often did you change out the water in the container? Or did you treat the cooling tower water? Since we run the stills 6 times per week, it seems I would still have to change out the water frequently to prevent corrosion and legionnaires' disease. I would rather not have an open loop cooling system and somehow make a closed loop system but I am not sure if that is possible within our limitations.
    There's not that much water in the sump of one of these things. You could dump it weekly, or even daily. SLO has had severe water restrictions, but the water used by this is insignificant. I used a spa/pool test kit, and dumped the water when the alkalinity got too high. Add spa chlorine sanitizer to maintain a residual chlorine level. Keep the pH neutral or basic (less corrosion). I thought about trying one of those floating sanitizers, but never bothered. When we weren't using it, I just drained it. My main circ pump sat on a pad next to this, and it was on the pavement against the exterior wall of the building.

    A closed loop system means you need to remove as much heat as you've put into the distillate. That's a LOT more energy than one of these uses.

    Regards,
    Mike Sharp

  7. #7
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    Quote Originally Posted by dleong View Post
    The thing I am having most trouble with is finding another cooling medium that can run through the condenser without worrying about contamination. We have had a pinhole leak in our condenser before, but since we were running city water, it was not a huge deal.
    In this case, I'd separate whatever the cooling source is (glycol or cooling tower) from the medium used to cool the condenser. So, one loop (glycol or cooling tower water) goes through a heat exchanger that cools a second "pure water" loop that goes to your condenser. Since you're recapturing your condenser water, you'd want to make sure the water was treated or replaced continually, so that it doesn't get bad itself. Clean water in a closed loop can still grow algae. That's one of the problems with RO systems, in fact.

    If your middle loop was potable city water (with chlorine/chloramine still in it), you could recirc the loop constantly with one of those Grundfos pumps, but bleed a little water from the loop to keep it fresh.

    Regards,
    Mike Sharp

  8. #8
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    What's your flow rate? 90° back down to 60° isn't a huge drop, if you've already got a glycol system, seems worth looking into whether a plate chiller can handle that drop and flow rate without maxing the system out. Circulate that chilled back to a small reservoir, then flush the whole system once or twice a week – yeah, you're still dumping water, but no more than a barrel or two at a time for any reasonable definition of "small reservoir," instead of hundreds. Heck, throw a T-valve on the system so you can still run hot water to the HLT until it's full, then start chilling back to the closed loop.

  9. #9
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    If you are going to have an evaporator system to cool the cooling water, then in the UK at least, and I am sure the rest of Europe and N America, you will need to treat this to prevent possible development an spread of Legionella. There have been several instances comparatively recently in the UK of people dying from Legionnaires disease spread by untreated or inadequately treated cooling tower water. Commonly used treatment is with ClO2. Check with your supplier of cooling kit, and also local / federal regulations.
    dick

  10. #10
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    Quote Originally Posted by rdcpro View Post
    In this case, I'd separate whatever the cooling source is (glycol or cooling tower) from the medium used to cool the condenser. So, one loop (glycol or cooling tower water) goes through a heat exchanger that cools a second "pure water" loop that goes to your condenser. Since you're recapturing your condenser water, you'd want to make sure the water was treated or replaced continually, so that it doesn't get bad itself. Clean water in a closed loop can still grow algae. That's one of the problems with RO systems, in fact.

    If your middle loop was potable city water (with chlorine/chloramine still in it), you could recirc the loop constantly with one of those Grundfos pumps, but bleed a little water from the loop to keep it fresh.

    Regards,
    Mike Sharp
    Mike,

    This is the type of system I was envisioning, having a glycol loop cooling the condenser going back into a small reservoir. Our max flow rate is roughly 14 GPM if we have multiple stills running. I would be fine with dumping the condenser water in the reservoir weekly and maybe testing throughout the week to make sure there is no fouling. This seems to be the simplest and best option for us with limited spacing and our current setup.

  11. #11
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    Quote Originally Posted by feinbera View Post
    What's your flow rate? 90° back down to 60° isn't a huge drop, if you've already got a glycol system, seems worth looking into whether a plate chiller can handle that drop and flow rate without maxing the system out. Circulate that chilled back to a small reservoir, then flush the whole system once or twice a week – yeah, you're still dumping water, but no more than a barrel or two at a time for any reasonable definition of "small reservoir," instead of hundreds. Heck, throw a T-valve on the system so you can still run hot water to the HLT until it's full, then start chilling back to the closed loop.
    Our flow rate is roughly 14 GPM and getting the water back down to 60 shouldn't put too big of a load on our chiller system. I would think we we would need a bigger reservoir than a barrel or so to keep up with the flow rate demands of our stills. Like I stated we could put in a 1100 gallon old blending tank we have to be our reservoir. Place the glycol/city water HX before the reservoir and pump the "chilled" reservoir water back to the still condensers.

  12. #12
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    Quote Originally Posted by dick murton View Post
    If you are going to have an evaporator system to cool the cooling water, then in the UK at least, and I am sure the rest of Europe and N America, you will need to treat this to prevent possible development an spread of Legionella. There have been several instances comparatively recently in the UK of people dying from Legionnaires disease spread by untreated or inadequately treated cooling tower water. Commonly used treatment is with ClO2. Check with your supplier of cooling kit, and also local / federal regulations.
    Dick,

    I would rather not have to go through a cooling tower for this application since it would probably have to be put on the roof which leads to more piping and continuous treatment cost. Thanks for your input though.

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