"The burner on my 60 gallon steam boil kettle is only 200K BTU and I can get 50 gallons from mash to boil in less than 15 min."
On planet earth at sea level. It takes 960 BTU/Hr per pound to take water from 212 deg F to 212 deg F boiling (change of state). 50 gall. weighs around 415 pounds. To bring that weight of water to a boil in one hour would take almost 400K BTU. The ducks don't line up for 15 minutes. I didn't figure in the BTU/Hr for the TD from mash temp to 212 F. That number would be, BTU/Hr = weight X TD. It takes a 50 HP boiler to boil 50 G of wort in a steam kettle in 15 minutes. Regardless, of whether the kettle is direct fired or remote. A 200 K steam boiler is about 6 HP. You need not verify my numbers on how much LP will be burned with a burner rated at 185K, or convert them to gallons, or tell me that I was close. But, thank you anyway. I used pounds because a home brewer knows that a tank is 20 pounds and really has no reason to know the volume. A pound of LP depending on purity is 21K-25K BTU/Hr pound.
I would be worried about scorching direct firing at 400K BTU thats an insane amount of heat for a 10 gallon brew. Would make a powerful HLT but I assume you throttle it back for boiling. My 15 gallon keggle system uses the BG-14s tweaked to 90K BTU and I had to back them back down to the 70K BTU because the boil was to vigorous.
