Natural Gas - 20 gallon brews

[Grossy]

I need some advice from people who ARE or have DONE 20 gallon batches using NATURAL GAS.

I am really having a hard time getting my Hurricane Burner (Banjo Burner), to bring 20 gallons to a rolling boil.

After achieving a boil, I can only maintain a rolling boil if I keep the lid 3/4 of the way over the kettle. Takes about 1.5 hours to bring 85 degree water to a boil.

I have an all-grain, three burner system.

Any suggestions would be helpful.


(Ps. Beside both being gas, there is really no comparison between propane and natural gas.)

 

[MNSmitty]

What size supply line do you have running to it? And how long?
If its too small, even if your burner is rated at XXX btu, it wont achieve it unless there is adequate gas supply.

 

[Grossy]

I am running off the house line, which is 1/2" black Iron pipe. I am running 1/2" black iron pipe all the way, right up to the burner orifice.

From where I have connected to the house line to the burner is about 10 feet. My guess is that the house line to the house regulator service is about 20 feet.

So 30 feet altogether.

 

[acidrain]

What are your other appliances?
I'm not a gas guy, but 1/2" seams small... Mine is 1" from the meter to my furnace, where it T's and runs 3/4" to my hot water tank and range. Both of those are stepped down to 1/2" flex line.
My gas guy said I was technically maxed out on BTU's, but in reality could run 3/4" to my garage if I wanted assuming that not all the appliances would be running at the same time.

 

[beernutz]

Caveat: I don't brew 20 gallon batches. I did however build a 1500 watt heat stick to help raise HTL temps quicker, adjust mash temps in my cooler, and sometimes supplement the gas burner under my boil keggle when doing 10 gallon batches. The heat stick works really well, so much so that I have to keep a close eye on the thermometers to be sure I don't overshoot and it is very flexible. That might be a relatively cheap, ~$50 in my case, option to consider.

 

[ThreeDogsNE]

When I lived in town I ran 1" pipe for natural gas to my brew rig. I have 12 inch 3 ring burners that struggled to boil the 14 or 15 gallons or so that lead to my 10 gallon batches. I left the lid on about 1/3 of the way to keep a respectable boil. If I wanted a better boil with a wide open pot, I added a heatstick. I now live on an acreage, and use propane through the same burners with a smaller orifice on the valves, and I get a nice rolling boil and can throttle back the valves with the lid fully off the kettle. Propane costs are not fun, though. If you have power in range, a 1500 watt 120 volt heatstick might get you over the hump.

edit: I see that Beernutz types faster than I do. His heatstick endorsement wasn't there when I started typing. I could have just said "ditto".

 

[coyote68]

are you using electric gas valves to control the burner? i had to adjust mine. i have a 3/4 in supply manifold reducing each burner to 1/2. i also used 10 jet burners and have no trouble getting a rolling boil within 45 min.

 

[acidrain]

This calculator might help: http://www.engineeringtoolbox.com/natural-gas-pipe-calculator-d_1042.html

Basically, household pressure means you can get 1000 btu's per cu ft of gas.
at 60ft of .5 id calculating for pressure drop, you have a capacity for 85,000 btu's.
Subtract for inefficiencies and you may be left with only 1/2 of that.

Read this article on how it was impossible to get 17 gallons to boil with a supposed 55,000 btu burner: http://www.brewinhome.com/389/size-does-matter/

I saw in your OP that you mention there is no comparison between NG and propane. Well, maybe for convenience, but in energy, propane has about twice the btu's available as NG.

 

[jackyl]

I am running off the house line, which is 1/2" black Iron pipe. I am running 1/2" black iron pipe all the way, right up to the burner orifice.

From where I have connected to the house line to the burner is about 10 feet. My guess is that the house line to the house regulator service is about 20 feet.

So 30 feet altogether.

What is your gas pressure in water column? The standard NG banjo orifices are sized for 11" WC. And of course check the orifice for spiders, my first run the flame was bad and I didn't figure out why til I found a dead spider blocking flow.

Also, how much waste heat do you have? Are you running a windshield with areas for exhaust? Pictures might help with suggestions for how to improve efficiency.

I've just got my NG rig built out and still need to improve the NG plumbing to it and make the windscreen set up more efficient, but I was able to get ~17 gallons of water to a rolling boil without a lid in a test run over the weekend.