Problem
Economiser saves 3,768,300 kJ/h. Boiler efficiency is 82% and fuel GCV is 40,000 kJ/kg.
Formula
Fuel saving=Q/(η×GCV)
Solution
=3,768,300/(0.82×40,000).
Answer
114.89 kg/h
Engineering check
Verify units, magnitude, assumptions and physical meaning before accepting the result.