Regenerative Thermal Oxidizers

Rule of Thumb Calculations

 

How much fuel does an RTO with 95% Heat Recovery consume when operating at 1500°F?

The enthalpy of air at 1500°F is 28.24 BTU/Ft³.

Disregarding the incoming temperature, the amount of heat required will be:

0.05 x 28.24 = 1.412 BTU/Ft³

Assuming a heat loss of 10%, this becomes:
1.412 x 1.1 = 1.5532 BTU/Ft³ ~ 1.6 MMBTU/H

Now insert the flow rate in SCFM (ex. 10,000 SCFM):
10,000 x 1.6 x 60 = 0.96 MMBTU/H (< 1.0 MMBTU/H)
—————–
10⁶

If process emits 60 lbs/hr of VOC (alcohol & acetate) with a BTU content of 13,000 BTU/lb:
60 x 13,000 = 0.78 MMBTU/H
———–
10⁶

The RTO burner will be:
0.96 – 0.78 = 0.18 MMBTU/H or 180,000 BTU/H or 180 ft³ /H of Natural Gas

If heat value of the VOC is greater than shown, the burner will consume less fuel.

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