Problem 2: amount of fuel in calcination

It is desired to produce 10 kg. mol lime from calcinations of (pure) in a rotary kiln. Producer gas of composition  and  is combusted with  excess air to obtain the desired temperature in the kiln. The limestone and air are supplied at 298K, whereas producer gas is heated to 900K. Lime is discharged at 1200 K and at 500K.

Calculate the amount of producer gas (1 atm. and 273 K).

Let Y kg mol is the producer gas

Material balance gives







Calorific value of producer gas= 11271 Y kcal.

Performing heat balance: Heat input= Heat output.

Sensible heat in producer gas+ calorific value of producer gas – Heat of decomposition of CaCO₃= sensible heat in  sensible heat in flue gases

We calculate all the values and get   Answer