Module 2: Combustion and heat utilization
  Lecture 20: Exercises on heat recovery
 


Exercise-4

Heat input                         

          % of total           

Combustion of fuel                      
    100

Heat output                           
                          % of total            
          
Process requirements                           
25
 Sensible heat in flue gases                                    
50
           Heat loss      
25

      The installation of air preheater is being considered. It is estimated that the proposed preheater would recover one half of the sensible heat in the flue gases and would return to the furnace. Draw energy flow diagram in each of the following cases also
a) If the daily process requirements and daily heat loss are kept same, what percent saving in fuel could be achieved by the preheater installation? What would be the new heat balance (in percent) ?
   
b) If the daily fuel consumption and daily heat loss are kept same, what percent increase could be made in heat furnished to the process as a result of the preheater installation? What would be the new heat balance (in percent) ?