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BoomerSooner
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Posted on 02/28/2020 12:01 PM
Hello all. I?m new to this forum, and plan on building a 2K drum roaster. I have access to a metal fan shop and scrap metal for that matter. Building should not be the problem, it?s all the technical stuff that I?m worried about. Right now I?m focused on burner options. I saw the post on Tejas burners. Do you think a 6? round burner will be sufficient enough for an 8.75x9.5 drum? Or should I explore the 8? as an option. Also I could make a pipe ribbon burner but do not know how many btu they put out. Any help with this info or a better way to search the forum because I can?t quiet figure that out. Thank you in advance
 
jscott14
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Posted on 02/28/2020 3:23 PM
This is almost impossible to answer without knowing more details about the design of your roaster (and even WITH details, will be difficult). A 6" Tejas burner can deliver over 100,000 BTU, which is MORE than enough heat... but is it right for your design?
Jet burners like Tejas uses can't be used in a closed box... they need to be fed ample amounts of outside air. For a roaster like mine, that rules out jet burner nozzles right out of the gate. This is why the style of your design is important. Will you just be heating air outside the drum and then pumping that air through the roaster? Then you might be ok.
Calculating the BTU of a given orifice size vs. gas pressure is fairly trivial (propane or natural gas will have different values here). How much you NEED is another question. For an RK drum roaster, they say 28,000 BTU is good for a pound or two, but then go on to say that 45,000 BTU is needed for 8 lbs, so their advice doesn't seem to be linear.
But if you're at 50,000 BTU or above, you PROBABLY have enough heat for 2 KG of green coffee. CONTROLLING that heat, however, is going to be your key (through gas flow, air flow, or a combination of the two).
 
BoomerSooner
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Posted on 02/28/2020 6:07 PM
Thank you for your response. My design is off the Diedrich 2.5. So yes the burner will be enclosed. It looked like the burner could be made up with any nipple length. I thought I would be able to have the Venturi and airflow dial on the outside of the roaster. I will be using natural gas.
 
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