Module 4: Heat transfer calculations, miscellaneous topics and carbon credit
  Lecture 41: Self assessment questions in fuels, furnace and refractory
 


13 In radiant heat exchange between two black surfaces the composite geometrical factor  due to refractory surface is

a)

b)

c)

d)

14 Why adiabatic flame temperature is greater than the actual flame temperature? Explain

15 Explain the difference between the following pairs

a) Natural draft and forced draft

b) Carbonization and gasification

c) Primary and secondary air

d) Luminous and non-luminous flame

e) Lignite and anthracite.

16 A fuel oil of composition 84.9%C, 11.4% H,   3.2%S, 0.4%0and  0.1% ash is burnt with 20% excess air. Assume complete combustion. The amount of air is closed to

a) 1400kg

b) 1672kg

c) 1500kg

d) 1650kg

 

17 The ultimate analysis of a coal(moist basis in %): C 69.8 , H 4.6 , N 1.4, O 8.5, S 2.5, H2O 4.5 and ash 8.7. The gross calorific value, moist basis, is 29920 KJ/Kg. Calculate, by means of the Dulong formula, the gross calorific value, moist basis, of the coal.

18 The proximate analysis of coal is: Moisture 2.4%, Volatile Matter 29.4%, Fixed Carbon 58%, Ash 9.7% and Sulphur 0.5%. Its gross calorific value is 7650 Kcal/Kg. Calculate proximate analysis and calorific value on

a) Moisture free basis