Module 2: Combustion and heat utilization
  Lecture 18: Energy flow diagram and fuel consumption


Exercise-1

A furnace melts 305 tons of copper and raises its temperature to 1600K in 6 hrs. The furnace consumes 4.2 tons/hr oil. Fuel oil analyses 85% C, 12% H and 3% O and its net calorific value is 9446 kcal/kg. Combustion air is 20% excess than theoretically required. Heat loss from the furnace to the surrounding is 50% of the heat that is required to melt copper and raise its temperature to 1600K. Calculate the inputs and outputs of energy and show them on the energy diagram

First we have to do the material balance to find out the amounts of POC and then energy carried by POC by using the sensible heat values.

Sensible heat in POC is calculated to be
Sensible heat in copper is calculated to be 
Heat  losses are 50% of the sensible heat in copper

Heat blance:

Heat input                         

              (kcal/hr)              

% of total
Calorific value of fuel              
          3.97 x  107   
100

Heat output                           
           (kcal/hr)              
% of total
    Heat to POC                               
2.54 x 107
64
    Heat to copper                            
0.95 x 107
24
      Heat losses
0.48 x 107
12