Download MineFire Pro+ USER`S MANUAL & TUTORIAL

Run a MineFire model using the Heat Transfer parameter calculated above, and the
Reference Q and assumed Lead Time values. Find the Avg Temp value in the fire branch
at the end of the lead time period – this value can be used to represent the temperature
variable in the gas emission formulas for wood fires in Figure 35 and Figure 36 above.
For this calculation, we will assume that our performance of this procedure resulted in a
temperature of 1000 ºC.
Solve the polynomial: y = 1000 = –0.0015x2 + 2.4282x + 120
Or
0 = –0.0015x2 + 2.4282x – 880
x = 548 or 1048 m3/ton
3
550 m /ton = 9.71 ft3 gas/lb wood
According to Speight [from 11], wood emits 25% CO at any temperature above 400 ºC,
so:
9.71 ft3 gas/lb wood × 25% = 2.43 ft3 CO/lb wood
Max burn rate, from above = 137.5 lb wood / min
Max emission rate = 137.5 lb wood / min × 2.43 ft3 CO/lb wood = 334 cfm CO
Using the assumption that the fire is burning in one compartment:
Emission rate = [31 ft.×20 ft (perim of 1 compartment)×0.0047 ft/min×17.58 lb/ft3]×
2.43 ft3 CO/lb wood = 124 cfm CO
For now, use Max emission rate as Flow Rate = 334 cfm. The fire will eventually engulf
the entire shaft. Re-evaluate this assumption based on simulation results.
Concentration = 334 cfm CO / (15,000 cfm) = 2.2% CO at the fire source.
3) Determine O 2 concentration
Determine the oxygen consumed by the combustion of the wood. Continue with the
assumption of 1000 ºC. The following are the reactions for wood that involve the
consumption of oxygen:
C + O 2  CO 2
C + ½ O 2  CO
H2 + ½ O2  H2O
9.71 ft3/lb x 20% O 2 = 1.94 ft3 CO 2 / lb wood
9.71 ft /lb x 25% O 2 = 2.43 ft3 CO / lb wood
9.71 ft3/lb x 35% O 2 = 3.4 ft3 H 2 O / lb wood
3
From above: Max burn rate of wood = 137.5 lb/min
137.5 lb wood / min × vol gas / lb = 267 cfm CO 2 × 0.0833 lb O 2 /min = 22.2 lb
CO 2 /min
334 cfm CO × 0.0833 lb/ft3 = 27.8 lb CO/min
467.5 cfm H 2 0 × 0.0833 lb/ft3 = 38.9 lb H 2 O/min
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