TUBE SEAL ANALYSIS
COST OF HEATING EXCESS AIR
Di
= process tube outside diameter
Di=
in
d
= inside diameter of hole in arch or seal plate which tube passes thru
d=
in
P
= negative pressure inside furnace from draft fan
P=
in. H2O
T
= flue gas temperature inside heater
T=
F
E
= efficiency which gas burners heat the flue gas
E=
%
N
= number of tubes which pass thru a furnace box
N=
ea
Cost
= average cost of fuel
Cost=
$/mil Btu
Assumptions:
1. Furnace runs continuously, 24 hours per day, 365 days per year.
2. Ambient air is 77 F and 2116.2 psf.
3. Effects of gas expansion due to heating are neglected.
4. No work is done by the heated air.
Total Yearly Cost=
Disclaimer for Thorpe Tube Seal Program
Results are based upon steady state theoretical calculations using standard thermodynamic equations.Actual results may vary.
