BTUs emitting from kiln

[howarddbennett]

The kiln is 200 feet long and 17 feet in diameter. The temperature of outside wall of the kiln is consistently 600F. The kiln runs 24/7/365. How do I calculate the total MBTUs per hour that are being lost to the atmosphere?

Thanks,

Dale

 

[IRstuff]

Why not just use your gas consumption values?

TTFN

FAQ731-376
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[ione]

Assuming 68 °F as ambient temperature and 0.2 as emissivity of the outer surface the order of magnitude is 11 Mbtu/h

 

[Fizz92]

Your best bet is to measure your gas flows. Natural gas = 1000 Btu/cf. Then look at a Sankey Diagram for a furnace. Energy In = Energy Out. IN is the fuel gas, OUT is hot flue gasses, heat into product, and losses. Kiln losses typically are from shell and from holes/leaks. Be cautious about adding insulation! This will raise the temperature of the existing refractory and structure, maybe beyond their limits. Also, if you add insulation then the temperature inside the insulation might drop below the condensation point of the flue gasses. Condensing water rich in acid inside the structure is bad.

Final note, be cautious of units.
1 M Btu/h = 1,000 Btu/h
1 MM Btu/h = 1,000,000 Btu/h
1 MJ = 1,000,000 J

For Imperial Units M = Mille = Thousand & MM = thousand thousand = million

For Metric Units M = Mega = million

Confusing the two systems is why (I've been told) the NFPA dropped MM Btu/h and M Btu/h from their standards (eg. NFPA 86)