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Thread: Boiler Sizing?

  1. #1
    Join Date
    Aug 2006
    Location
    Meadville, Pa
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    6

    Question Boiler Sizing?

    We have a 10 bbl (Pub Brewing) Kettle Steam Jacketed and am trying to find a formula to size my boiler. I used to know this but can't seem to find my notes. It has channel jackets on both bottom and side. I currently have the boiler that came with it, but am sure that it is undersized at 4 hp/150,000 Btu. looking for comparisions of formula. Thanks

    Matt

  2. #2
    Join Date
    Oct 2002
    Location
    California
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    20

    Boiler Sizing

    Matt,

    I generally size 1 BHP (boiler horse power) per barrel of brewhouse capacity for our brewpub systems. You can get away with less, but a lot depends on how close the boiler is to the brewhouse, hot liquor tank usage, steam pressure and the size of the steam supply line. Your 4 HP boiler is small for a 10 bbl kettle. You may still get to a boil but it will definitely take longer than with a properly sized boiler.

    Rob

  3. #3
    Join Date
    Apr 2004
    Location
    Hastings, MI, USA
    Posts
    263
    This might help Sussman Electric Steam Boiler Ratings. Mine's an ES-72 and will rock a boil on my 7 bbl system.
    "By man's sweat and God's love, beer came into the world" -- St. Arnold of Metz

  4. #4
    Join Date
    Feb 2004
    Location
    Dexter, MI USA
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    203
    Hello Matt,

    John Mallet suggests 50,000 BTU / hr per BBL. So, in agreement with everyone else, your boiler is a little small. I would think you will be able to boil (on a windless day), but it will be a while in coming. I have used systems with smaller than John's 50K / BBL / hr, but with longer run-off (time wise) British styled systems, and still perhaps a little wait for a good boil.

    If you can afford it, a new boiler will hasten your day. But, hey, you've seen my brewery. You can make it work.

    Cheers,
    Ron
    Jolly Pumpkin Artisan Ales
    PS Glad to see your project coming along. When will you be able to begin brewing?

  5. #5
    Join Date
    Jun 2009
    Posts
    70
    Hmmmm.... conflicting POV here

    1 BHP per BBL or 50000 BTU/hr per BBL

    problem is that 1 BPH = 33475 BTU/hr so why the discrepancy? Sure an extra 16,500 or so BTU/hr would be nice... but is it necessary?

    What standards do you use?

    Looking to size a steam boiler for a 20 BBL brewhouse. Found a 20 BPH boiler kicking out 670,000 BTU/hr which is right in line with the 1 BPH/BBL but shy of 50000 BTU/hr/BBL....

  6. #6
    Join Date
    May 2004
    Location
    St. John's, Newfoundland, Canada
    Posts
    816
    Assumptions:

    Evap loss - 1.5% hour, boiling loss 5%/hour
    Sp. heat of grains 0.42
    Sp. heat water 1.0
    Sp heat wort 0.92
    Single step downward infusion mash, mashing off to 170 F
    Warming equipment loss 2%
    Radiative loss 10% for kettle, 12% for mash tun
    Mash volume ratio - 1.25 bbl/100 lbs grist
    Sparge volume ratio - 1.6 bbl/100 lbs grist
    12.5 oP wort
    Mash process time 70 min
    Conversion temp 150 F
    Kettle filling time - 120 min
    Boil time 60 min
    contraction on cooling - 4%
    Process water recovered from cool - in @145F
    Average temp process water - 170F

    Now that's out of the way -

    10 bbl - Brewhouse inputs alone = 587K BTU
    Kettle - 405 k BTU
    mash tun - 88 k btu
    HLT - 94 k btu

    20 bbl - Brewhouse inputs alone = 1.2M BTU
    Kettle - 810 k BTU
    mash tun - 176 k btu
    HLT - 187 k btu

    These numbers will change dramatically if you are heating city water from ambient.

    Pax.

    Liam

  7. #7
    Join Date
    Jan 2003
    Location
    Palau
    Posts
    1,611
    Nice work, Liam. Note that these loads won't be simultaneous and that in my experience the highest heat load occurs while heating the kettle during lauter. This depends of course on how fast you lauter. Your load might be highest if you are brewing back-to-back batches and need your HLT to heat quickly. But even this could be offset (or eliminated) with an efficient heat exchanger that gives you an even 80C water output during knockout. So much depends on your process and technique as well as the equipment. Even how you install the steam. Air eliminators are an easy way to increase heat flux to your tanks, for example. Get a crackerjack installer for your boiler and size it a bit larger than necessary. Good luck!
    Phillip Kelm--Palau Brewing Company Manager--
    Worldwide Brewery Installations
    www.GitcheGumeeBreweryServices.com

  8. #8
    Join Date
    Jun 2009
    Posts
    70
    Ok so more info... I will be using a heat exchanger for my hot water needs (mash, lauter, etc) so I won't need so much to heat up an HLT. I think my main load will be during boil. My Kettle has three steam zones so I can start heating pretty quickly.

    Now I am seeing another figure that is confusing me. Looking at the specs for a boiler I am looking at it says it has a gross SBI output of 693K BTU/hr and then says Net SBI steam is only 521k BTU/hr. So when we are talking sizing are we talking Net or gross? And what the heck is SBI?

  9. #9
    Join Date
    May 2004
    Location
    St. John's, Newfoundland, Canada
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    SBI = steel boiler institute. It's a rating code for steel boilers. See here.

    Net is the number you are interested in.

    This is also at the exit of the steam piping from the boiler. It does not take into consideration the loss in steam piping/radiative loss before the steam reaches your brewhouse. Steam pipe insulation can mean a big difference in effectiveness to an otherwise borderline boiler (in terms of sizing for brewhouse).


    Pax.

    Liam

  10. #10
    Join Date
    Jun 2009
    Posts
    70
    Anyone put boilers in line? Go with 2 or 3 smaller sized boilers and let em fire as needed? My boiler guy is trying to tell me 1M BTU/Hr is overkill.

    Also, what pressure do you run the steam? It must be low if we're requiring this much heating capacity.

  11. #11
    Join Date
    Jan 2003
    Location
    Palau
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    You will want a low pressure steam boiler. This means it tops out at 15psi and normally operates at 13psi. BTU/hr is certified at a given pressure, so more or less pressure doesn't make any difference--you run the boiler where it's designed to run. I've never worked with multiple boilers, but I don't like the idea. Each boiler has lots of expensive instrumentation that fails often enough as is. Don't need multiple sources of failure. KISS principle. And 1MBTU/hr does sound like overkill for a 10BBL brewhouse. Unless you're brewing at extreme elevations. Boilers get derated for elevation. 600k or 700k would be my guess as the right size. Also, make sure your boiler guy installs air eliminators and vacuum breakers. I've seen lots of installs without these and it does make a big difference in heating capacity. Good luck!
    Phillip Kelm--Palau Brewing Company Manager--
    Worldwide Brewery Installations
    www.GitcheGumeeBreweryServices.com

  12. #12
    Join Date
    May 2004
    Location
    St. John's, Newfoundland, Canada
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    816
    There are modular boilers that step fire on demand out there. They are very efficient in terms of energy use. Many boilers also have a two stage firing system (low/high).

    Pax.

    Liam

  13. #13
    Join Date
    Jun 2009
    Posts
    70
    I have a 20 BBL brewhouse.

    Quote Originally Posted by gitchegumee
    You will want a low pressure steam boiler. This means it tops out at 15psi and normally operates at 13psi. BTU/hr is certified at a given pressure, so more or less pressure doesn't make any difference--you run the boiler where it's designed to run. I've never worked with multiple boilers, but I don't like the idea. Each boiler has lots of expensive instrumentation that fails often enough as is. Don't need multiple sources of failure. KISS principle. And 1MBTU/hr does sound like overkill for a 10BBL brewhouse. Unless you're brewing at extreme elevations. Boilers get derated for elevation. 600k or 700k would be my guess as the right size. Also, make sure your boiler guy installs air eliminators and vacuum breakers. I've seen lots of installs without these and it does make a big difference in heating capacity. Good luck!

  14. #14
    Join Date
    May 2004
    Location
    St. John's, Newfoundland, Canada
    Posts
    816
    For a 20 bbl brewhouse, 1Mbtu is about the right size.

    If your boiler guy disagrees, get a second opinion.

    You've already had a few here.

    Pax.

    Liam

  15. #15
    Join Date
    Oct 2006
    Location
    Madison, WI
    Posts
    43
    I'm in the process of putting together a brewery using old dairy equipment and have an old steam jacketed "processor" for my kettle. It is 400 gallons, rated for high pressure and has three zones. I intend to run it on low pressure steam.

    Problem is contractors (other than ones out in the sticks that have done dairy processing plants before) are scared to touch it and want me to hire an engineer to design the steam system...for one little kettle! Estimates of what I'll need in terms of a boiler (which will be located about 60-75 feet away) are 350K-500K. Once you get up to 500K it involves a different license to install and run the boiler in WI (so I've been told).

    My question is did those of you who may have put together your own system have to hire an engineer to design your steam system for you in order to get it installed?
    Page Buchanan
    House of Brews
    Madison, WI

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