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Steam Boiler Requirements

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I'm in the beginning stages of starting a distillery in California and I'm pretty confused over the steam boiler component of the system. I'm going to be getting a 200 gal 4 plate column still. Heat recommendations I've seen range between 400k-600k BTUs (I'm not running a mash tun or anything, just the still). I've heard that certain sized boilers require separate enclosures built out of fireproof materials with a certain amount of ventilation and certain amount of space around the unit. Some have told me it needs to be outside some have told me it needs to be inside. Some have told me you don't need a boiler room at all. I'm finishing up tenant improvements negotiations with my landlord and I need to tell him what I will need him to build into the building. Can anyone offer me some advice on this? Or direct me to the correct agency to contact or website to review?

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Howdy,

i am going to use a hot water / glycol system you will still use a boiler but is is much safer and efficient. your boiler needs my be smaller also.

check with your local fire and electrical inspectors before you build. 

Mr Whisky

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That is correct but according to distillery standards once you are 5 feet away from the still spout you are safe. Local fire Marshall will make that call   I will have mine in a separate room. 

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California Building Code 2016 : Table 509 requires separate boiler room if you are running a high pressure boiler (above 15 psi) and above 10 HP (about 330,000 BTU/hr). I am assuming you are planning to use a low pressure steam boiler, so you shouldn't need a separate boiler room. Unless your city has more stringent requirements above and beyond the California code. Ask a local boiler company.

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Putting the boiler and associated utility equipment in a utility room is good practice.  There are numerous safety benefits, and it's not generally very expensive.  We built our boiler room out of cinderblock, and the masons had it done in a day.

Personally, I would lean closer to 600kbtu than 400kbtu, the cost differential is minor, and the time savings in heatup is going to be significant.

 

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1 hour ago, Silk City Distillers said:

I would lean closer to 600kbtu than 400kbtu

Assuming 75% efficiency you're looking at either 300 kbtu or 450 kbtu.  His heating needs are:

  • 200 gallons = 1668 lbs
  • 200 gallons from 75F to 212F = (212-75)*1668 = 228,516 BTUs
  • 200 gallons from 212 to vapor = 970 * 1668 = 1,617,960 BTUs

In my experience he won't have enough load for the boiler to run efficiently -- it's going to be short cycling to beat the band, and although it's not hard on the boiler, it will kill efficiency ($$$$).  He needs roughly 250kbtus to heat up the still to boiling and another 1.6mbtus to vaporize the entire contents of the still (clearly he won't be doing this). The question that's difficult to answer is how fast can the heat be transferred from the steam jacket to the contents of the kettle.  Delta-T is a factor (operating the boiler at 9 psi rather than 2 psi has it's advantages) but so is the architecture of the kettles (a "tablet" shaped is better than a cylindrical shape).  I'd bet he wont see appreciably faster heatup times with a 600k than a 275k boiler because of the heat transfer rate and the fact the boiler will have serious short-cycling problems -- a 600k boiler wont push heat in any quicker than a 400k boiler. That being said, when he upgrades to a larger still he'll be good to go.

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well said,

i would keep the boiler room as close to the still as possible. search out your boilers.  they make very efficient boilers that are high btu's and small in size.

 

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I run a 265 gallon still and a 15.6 hp boiler (522kbtu).  There is no cycling during heatup, as the burner fires continuously for nearly the entire heat-up cycle.  The still can easily consume 100% of the steam produced by the boiler - as evidenced by not being able to build full pressure during heat up.  It's not until the still nears boiling that the boiler will "catch up", build to full pressure, and cycle.  At that point the pressure in the still is dialed back to 1psi or so, and the boiler cycles on a few times every hour.  I run 2" steam lines and the both steam and condensate lines are shorter than 10 feet, traps are appropriately sized.  My suggestion to be nearer to 600k than 400k is based on my actual operating experience using similar sized equipment.  I have absolutely zero doubt I would be able to easily consume another 5hp.  

The line between having additional steam capability available to accommodate a still upgrade, additional still, or some additional steam equipment (heat exchangers for hot water, etc) and inefficiently oversizing your steam system isn't narrow, and the cost differential to give yourself additional headroom is peanuts compared to tearing out a relatively young boiler.

Do with my anecdote whatever you wish.

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39 minutes ago, Silk City Distillers said:

 

I run a 265 gallon still and a 15.6 hp boiler (522kbtu)

 

Do you have a steam accumulator? 

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Wouldn't imagine it would be applicable in this scenario as accumulators are generally only used in processes that have sporadic/intermittent high-volume demands - not steady state heating.  I've actually only ever seen one once, and it was in a plant that used high pressure steam which kept accumulators at something like 150psi before they were regulated down to process pressure.  We run a 4" header which adds some additional (albeit minor) steam capacity.  But, at 10-15psi, an accumulator would need to be absolutely massive given the still jacket volume.

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6 hours ago, Silk City Distillers said:

There is no cycling during heatup, as the burner fires continuously for nearly the entire heat-up cycle.

I'd be interested in hearing more about your setup.  10 psi steam has a volume of somewhere around 16 cubic feet / lb.  Your boiler produce around 500 lbs of steam (I think) / hour which is enough to completely fill a small home. I can't for the life of me figure out how a jacket on a 265 gallon kettle has enough volume to hold that amount of steam.  Does you WM have the ability to underfire the burners or are they open to atmosphere / bunsen style?

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Condensate...

500 pounds of steam per hour is equal to 500 pounds of water.  8.3 pounds per gallon is 60.2 gallons of condensate returned to the boiler per hour - which is a gallon a minute - a trickle really.  It's actually rated a bit higher - 521 pounds per hour.

My boiler uses a power burner with a motor driven fan - not open flame style like in a home boiler.

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I've helped size a bunch of breweries and distilleries and, if it's a small setup like your case, would be much beneficial of using a low pressure steam boiler (15psig MAWP) and running the boiler at 10-12 psi and using a 2" SCH80 pipie will be sufficient enough to run the steam capacity. Now for your boiler size:

Q = mCdT = 200 gal * 8.345 lbs * (1) * (212-60) = 253,688 BTU/hr and since you are using 10-12 psig (from steam tables the latent heat is 950 BTU/lb)

Q = 253,688 / 950 = 267.04 lbs/hr 

Q = 267.04 / 34.5 = 7.75 BHP

The next boiler size will be a 10BHP = 337,450 BTU/hr

Let me know if you need help with a quote :)

Good luck.

Also remeber that most california requires that the boiler needs to be below <9ppm NOx (some areas are <15ppm NOx).

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Is that gross or net steam?  We've got a Weil-McClain LGB-6 which is a 15.7hp boiler.  Should satisfy our needs for a 200 gallon still and 200 gallon mash tun.  Just curious what others are running.

 

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@Killbuck Creek for a 200 gal still and masher you need 15.35 BHP, so lets do the example, since your boiler is a 15.7 BHP = 541.65 lbs/hr, and the feedwater temperature needs to be maintain in between 160-180F to avoid any thermal stress to the steam boiler, and your operating pressure is below 15psig, using the enthalpy and steam tables, we get that the gross steam is 15.7BHP * 34.5 lbs/hr * 0.958 = 518.9 lbs/hr. 

And my previous calculation is done in NET steam.

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On 4/7/2017 at 10:49 AM, boilerguy said:

I've helped size a bunch of breweries and distilleries and, if it's a small setup like your case, would be much beneficial of using a low pressure steam boiler (15psig MAWP) and running the boiler at 10-12 psi and using a 2" SCH80 pipie will be sufficient enough to run the steam capacity. Now for your boiler size:

Q = mCdT = 200 gal * 8.345 lbs * (1) * (212-60) = 253,688 BTU/hr and since you are using 10-12 psig (from steam tables the latent heat is 950 BTU/lb)

Q = 253,688 / 950 = 267.04 lbs/hr 

Q = 267.04 / 34.5 = 7.75 BHP

The next boiler size will be a 10BHP = 337,450 BTU/hr

Let me know if you need help with a quote :)

Good luck.

Also remeber that most california requires that the boiler needs to be below <9ppm NOx (some areas are <15ppm NOx).

Boiler Guy 

I'm new to distilling and hav began sourcing equipment, the we have decided upon a 300 gal pot still and a 500 gal Mash cooker, the proposed still manufactuer states that we will need at least a low pressure, 800,000 btu boiler. I have been searching the net for references coming up dry we don't have plans to run the pot still and the Mash cooker at the same time, would the recommended btu be somewhat excessive 

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4 hours ago, Lorenzo said:

Boiler Guy 

I'm new to distilling and hav began sourcing equipment, the we have decided upon a 300 gal pot still and a 500 gal Mash cooker, the proposed still manufactuer states that we will need at least a low pressure, 800,000 btu boiler. I have been searching the net for references coming up dry we don't have plans to run the pot still and the Mash cooker at the same time, would the recommended btu be somewhat excessive 

@Lorenzo

Since you will never run them at the same time, you will have to size the steam boiler for the masher, since that one is bigger than the still, and if we follow the equation above we can come up that a 500 gal masher equals 635,000 BTU/hr = 668.5 lbs/hr = 19.38 BHP so you will need a 20BHP boiler to take care of the masher, but the boiler will run at high fire during the mashing if you want to save some fuel I will recommend to go for a 25BHP. 

Just FYI running the entire system at the same time you need is about 1 MMBTU/hr which equals 30BHP, the price increase is really not that much from a 20 to a 30BHP. Let me know if we can help you with a quote.

Good luck.

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