Economizer Heating Surface and Outlet Flue Gas Temperature Calculation  
Inputs = Yellow colour cells  
S.NO Description Sign Values UOM  
1 Steam production  Qs Kg/hr  
2 Flue gas inlet temperature  To oC  
3 Water  Quantity  Qw
home:
It is equal to steam production
Kg/hr  
4 Water inlet temperature    to oC  
5 Water outlet temperature t oC  
6 Steam & fuel ratio  R    
7 Heat transfer coefficient In economizer  K
home:
As per Hugot 20 to 30 Kcal/m2/hr/oC
kcal/m2/hr/oC  
8 Solid unburned coefficient      α    
9 Moisture of bagasse  W %  
10 Excess air   m %  
Result  
1 Weight of air  required per kg of bagasse                           Pa
home:
5.76 (1-W) m
Kg/hr  
2 Weight of the gaseous products of combustion per kg of bagasse  A
home:
5.76(1-W)m + 1
Kg/kg of Fuel  
3 Fuel consumption                  F
home:
Qs / R
Kg/hr  
4 Total air requirement            P
home:
F x Pa
kg/hr  
5 Flue gas Quantity  Pg
home:
F X A
Kg/hr  
6 Specific heat of water          CW Kcal/kg  
7 Specific heat of flue gas      CF
home:
0.27+0.00006T
Kcal/kg  
8 Ratio r
home:
Ratio ( r ) = (α x Pg x Cf )/ (Qw x CW )
   
9 Flue gas outlet temp T
home:
Flue gas outlet temp ( T ) = To -( (t - to )/ r )
oC  
10 Heating Surface  S
home:
Heating Surface ( S ) = α PC / K(1-r) ln (To-t)/(T-to)
M2  
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