sizing boiler for brewery

breweryboiler

Help!



I am getting very different answers to the question of what size boiler I need for my brewery. Basically, I need a steam boiler that will bring 250 gallons of water from 140 degrees F to a rolling boil within 45 minutes or so, and keep it there for up to 2.5 hrs. We are less than 100 feet above sea level, and the run from the boiler to the kettle is less than 25 feet including vertical rise (maybe 8' of vertical rise). This will be a low pressure boiler as the jackets on the kettle can't exceed 14.7psi. We have a 300,000btu 7hp propane boiler lined up but want to make sure it is right before hooking it up. Does this sound good? My plumber asks how many lbs of steam/hour and I don't have an answer. I'm hoping someone here can help. It is for a good cause: BEER!

Alan (California Radiant) Forbes

Brewery

work for a brewmaster who has a medium size Brew Pub.  His boiler is a Hydrotherm VGA 350 BSPV, 350,000 input (steam) and he seems happy with its performance.

Mike Kusiak_2

300k input seems reasonable

Some rough calculations:



1 Gal water = 8.3 Lbs,  so 250 Gal = 2075 Lbs



Temp rise from 140F to 212F (boiling) =72F





Number of BTU's needed to bring water to boiling in 45 min:



2075Lbs. x 72F x 1.33 = 198,000 BTU





Assuming your boiler is 80% efficient with 300,000 BTU input, steam output will be 240,000 BTU, which would give you some to spare for piping losses, etc.



Once the liquid in the kettle reaches 212F, boiling begins and all available heat will be used to boil contents since there will no longer be any temp rise.

Alan (California Radiant) Forbes

Nice math

but what happened to the 970 BTU's to take one pound of water from 212° not boiling to 212° boiling?

Mike Kusiak_2

Latent heat

Once the water reaches 212F, the 970 BTU will take one pound of water and transform it to one pound of steam at 212F, which he doesn't want to to to the entire contents of the kettle. I don't really know exactly how to represent a "rolling boil", but I assume he will boil away only a fraction of the contents of the kettle. The 240,000 BTU output of his boiler would be capable of boiling off 250 pounds per hour, or 30 Gal per hour of kettle contents.





 It would be nice to have some modulation capability on the burner so he could adjust the heat input once the kettle started to boil. Otherwise, a pressuretrol on the boiler and some means to throttle the steam to the kettle jacket might work to control output.

Charlie from wmass

For plate pasteurizers we use

a air powered pressure regulator to adjust the steam to the plates this allows for a high pressure steam boiler to supply the steam and the regulator to adjust the temperature.

breweryboiler

thanks guys

Thanks for the responses guys, I thought I would post what I found FYI.



I did the same math as Mike K. but as it turns out that is to low for what we really need. I am not turning the contents of my kettle all over to steam, but I guess a good rolling boil requires more than the straight math would indicate. While the original boiler included with this type of system was the same in terms of btu input/output as the one we had lined up, it was more to meet a price point for marketing. This produced a simmer (not ideal for consistent brewing) and only the kettle could be heated when in use, it was a shortcoming, but easily fixed. After talking to a current manufacturer (this system is no longer being produced), what we really need is a 400,000btu input for a 320,000 output at 80% efficiency. This allows for the cycling of the boiler without effecting the continuity of the boil. At that size we will spend the extra few hundred dollars to get the 450,000btu input which should allow for a loss of efficiency over time and give me plenty of extra heating for large batches and simultaneous heating of a second hot water tank for cleaning.



I think a lot of the confusion was on the input/output and the fact that in HVAC, a drop across the system is normal. To stay at exactly 212F boiling without it falling off to even just a low simmer while the boiler cycles requires more heat in the steam.



Some relevant beer trivia: You want a good rolling boil to promote what is called a "hot break". This is when protein from the malt starts to come out of solution and coagulate in the kettle. You want to leave it behind because it will make the beer cloudy among other issues. We leave it behind by whirlpooling the wort (this is what the solution is called before it is fermented into beer) after the boil is done. This causes the solids in a liquid (in this case the protein and hop residue called trub) to settle in a nice neat pile at the bottom of the vessel. You can observe this the same way Einstein did when he discovered it, by stirring your tea and watching the way the leaves always settle in the center of the cup.



Thanks again, I'm glad I found this forum.

breweryboiler

thanks guys

Thanks for the responses guys, I thought I would post what I found FYI.



I did the same math as Mike K. but as it turns out that is to low for what we really need. I am not turning the contents of my kettle all over to steam, but I guess a good rolling boil requires more than the straight math would indicate. While the original boiler included with this type of system was the same in terms of btu input/output as the one we had lined up, it was more to meet a price point for marketing. This produced a simmer (not ideal for consistent brewing) and only the kettle could be heated when in use, it was a shortcoming, but easily fixed. After talking to a current manufacturer (this system is no longer being produced), what we really need is a 400,000btu input for a 320,000 output at 80% efficiency. This allows for the cycling of the boiler without effecting the continuity of the boil. At that size we will spend the extra few hundred dollars to get the 450,000btu input which should allow for a loss of efficiency over time and give me plenty of extra heating for large batches and simultaneous heating of a second hot water tank for cleaning.



I think a lot of the confusion was on the input/output and the fact that in HVAC, a drop across the system is normal. To stay at exactly 212F boiling without it falling off to even just a low simmer while the boiler cycles requires more heat in the steam.



Some relevant beer trivia: You want a good rolling boil to promote what is called a "hot break". This is when protein from the malt starts to come out of solution and coagulate in the kettle. You want to leave it behind because it will make the beer cloudy among other issues. We leave it behind by whirlpooling the wort (this is what the solution is called before it is fermented into beer) after the boil is done. This causes the solids in a liquid (in this case the protein and hop residue called trub) to settle in a nice neat pile at the bottom of the vessel. You can observe this the same way Einstein did when he discovered it, by stirring your tea and watching the way the leaves always settle in the center of the cup.



Thanks again, I'm glad I found this forum.