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So I am looking at my equipment and my current situtaiton is as follows. I have a direct heat still with thump keg and condenser and I have a steam jacketed mash tun. I am trying to decide if A. I should just find a direct heat Mash Tun and go the route of avoiding steam for now in order to keep cost down or go ahead and find a steam boiler and steam heat the mash tun and keep the still direct heat (saves alot in up front costs). The question I have is, Is a natural gas boiler safe? Can it be used in the context of a distillery? Is anyone currently using a nat. gas boiler for steam generation?

Brian

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So I am looking at my equipment and my current situtaiton is as follows. I have a direct heat still with thump keg and condenser and I have a steam jacketed mash tun. I am trying to decide if A. I should just find a direct heat Mash Tun and go the route of avoiding steam for now in order to keep cost down or go ahead and find a steam boiler and steam heat the mash tun and keep the still direct heat (saves alot in up front costs). The question I have is, Is a natural gas boiler safe? Can it be used in the context of a distillery? Is anyone currently using a nat. gas boiler for steam generation?

Brian

*edit* Nevermind, after thinking about this after the benadryl wore off I was backwards.

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Not to be vague but there is a lot of debate and questions about the same thing on here. I myself have been going back and forth on the same exact thing.

I'm almost positive but think it will come down to local codes that you need a separate room for your boiler.

I'm 95% set on going electric currently, various reasons like energy costs and what type of safety codes a boiler could bring up.

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A lot depends on whether you can negotiate gas pricing (bulk buy) or not and the relative cost of electricity as mentioned before.

If you are getting any help from a local grant, this may point you in a direction.

Generally the larger you go in size, the better the Gas alternative looks, as first cost goes (relative install labor being almost the same).

Good luck.

Mike

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Thanks, this helps greatly. I'm not really concerned about the energy use, so long as it isn't crazy high and with the price of nat. gas falling I feel its's a sound investment for up front costs. I do have a separate room for it to be installed in so that's not an issue. I am working with the city to check local and state codes regarding it's use and location. I've been able to find several gas powered steam systems that are about 1/3 the cost to purchase and install vs an electric system.

Thanks

Brian

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Does anyone know a "rule of thumb" on sizing boilers? We are looking at steam-jacketed mash tun as well as still, but are not sure how big a boiler makes sense. Also, since efficiency seems to favor running a boiler at near capacity, would we do better to size for simultaneous operation of still and mash tun, or just plan on running one or the other? Any thoughts appreciated. Thanks, John

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1 lb/hr steam flow per gallon of capacity. this will get you a heat up time of about an hour from cold to pushing vapor.

this translates out to a bit better than 1000btus per gallon, gas input

so typically for a 300 gallon still and 300 gallon mash cooker, you want at minimum a 600,000btu boiler

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There's a good way to estimate :-)

However, while it may be a nice way to help get your business plan going, and window shop boilers, you should invest some time in understanding steam heat transfer. A big-ass boiler won't help you if your runs are undersized. Most boiler guys I know are happy to help explain the ins and outs of your installation. You should be armed with an understanding of how much heat it takes to run your processes. Knowing what a lb/hr steam is, BTUs, Boiler HP, all your delta T's, the specific gravity, and heat capacity of the materials you are heating will help save you money in the long run.

In a scenario that I recently worked out, I needed a 502000 BTU boiler to power a 100 gal still and a 400 gallon mash tun...but my time requirements and delta T's are probably different from Steven's assessments

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Natrat, it depends on a umber of factors, efficiency of the steam jacket and projected heat up time.

I use these numbers as a minimum, which yeilds a approximate 1 hour heat up. higher btu ratio will make for a faster heat up time, but, you will still be limited to a 4 hour spirit distillation time, except for stripping runs.

the still you are currently running has a lower btu/volume ratio, roughly 2/3 of the steam minimums. this along with more surface area shedding heat to air, makes for an approximately 2 hour heat up.

in essence its all relative, what you are willing to accept as a heat up time, cost, and convenience.

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I am by no means a boiler expert, and have relied on advise from this board on mine. That said, I am currently running a 300k gas fired steam output for my twin 90 gallon stills with no problems of capacity. The boiler seems to run aprox 50% of the time! and I don't yet have my condensate return pump installed, so that should bring me down some more.

I see a lot of discussion on here about wanting to run a mash tun at the same time as the stills, and think it is worth discussing. As an example natraj was talking about a 400 gallon tun and a 100 gallon still. If I'm not mistaken you can't (or maybe more appropriately don't need to) run a 400 gallon mash tun to feed a 100 gallon still, every day.

Even with 2 still runs per day, the mash capability is going to out produce the distillation by 2x, and will probably be more like 4x. So the still will operate every day, but the tun will only operate about every 3 to 4 days, and even then, for a few short hours. Therein lies the question of how large a steam boiler should you actually install, when it's capacity is essentially under utilized virtually 80% of the time? As such the boilers are inherently oversized and not efficient and considerably larger and more expensive then perhaps need be.

You almost have to wonder if in all of these small start-up operations where a lot of people are tight on money, if these boiler systems are not way oversized, vs what is really needed.

For myself I found a mint 12 month old steam boiler on craigslist for $850- and installed it myself with a HVAC expert as an advisor. This turned a $30g project into a $5g project and was a fun learning experience.

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I have a 600 gallon still, but only a 399K BTU boiler. After months of trial and error, I believe the 1000 BTU per gallon stated above by Steve is correct. I have taken to running my still under-charged to 400 gallons and it runs amazingly well. If I put 600 gallons in it, all hell breaks loose. The boiler runs too hard trying to get up to temperature. The pressure maxes and out you just never want to run anything at redline for hours and hours. Get the highest BTU boiler you can afford, and don't go below 1000 BTU per gallon. My first upgrade at the distillery will be a bigger boiler. For now, the 400 gallon runs make fantastic rum and my distilling days are fast and efficient.

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As usual, Steven is spot on. I wasn't disputing his numbers, merely trying to point out that any given system is more complex than using a rule of thumb.

The other thing is that I am approaching these issues from a production standpoint. My own expertise in the industry is not only setting up operations, but expanding them and bringing production efficiencies into play.

You do not need a 400 gallon mash tun to supply your 100 gallon still. You can do it with a small tun. However, preparing grain and fermenting takes the same amount of time whether you are making 50 gallons of wash or 500 gallons of wash. It seems inefficient to me to make washes that are sized to your still. Better is to mash once a week and spend the bulk of your time distilling...it takes less effort, less time, and (appropriately scaled) less money.

This is a thread about boiler sizing, so I'm not going to soapbox about capacity efficiencies and production-volume ratios.

I agree that many people oversize their boilers, but I'm not sure this is a bad thing. Generally, running an oversize boiler will save on maintenance costs, and with some designs larger boilers at low capacity may actually be significantly more efficient (energy wise) than smaller boilers. If you have room to expand and plan to, excess steam capacity is a really nice thing to have...for, say, a Hot Liquor tank...or a steam tunnel...or even a water hammer.

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