ANNA UNIVERSITY QUESTION PAPER
B.E. DEGREE EXAMINATION.
II Semester Metallurgical Engineering
FUELS, FURNACES AND REFRACTORIES
Time : Three hours Maximum : 100 marks
Answer ALL questions.
PART A — (10 ´ 2 = 20 marks)
1. Mention two properties desired of metallurgical coke.
2. Give one advantage of using steam in the manufacture of producer gas.
3. List the six components of coal that are tested in ultimate analysis of coal.
4. What is the need to use excess air in combustion of coals?
5. Differentiate natural convection and forced convection.
6. Define black body and gray body.
7. What is spalling resistance of refractories?
8. Give one advantage and one disadvantage of using carbon as refractory material.
9. What is cold junction error in thermo–electric pyrometers?
10. Differentiate direct arc furnace and indirect arc furnace.
PART B — (5 ´ 16 = 80 marks)
11. Describe the construction and operation of cupola.
12. (a) Describe the distillation of liquid fuels using a primary distillation unit.
(b) What is water gas? How is it manufactured in a water gas generator?
13. (a) What is octane number? How is it tested experimentally?
(b) Calculate the theoretical air requirement for combustion of one kg. of coal if the coal contains 80% carbon, 5% hydrogen, 3% nitrogen, 2% oxygen, 2% sulphur and the rest ash.
14. (a) Calculate the heat transfer rate per 1 m2 of surface area through a steel plate of thickness 100 mm, if its one side is maintained at a temperature of 120°C and the other side at 100°C. Thermal conductivity of steel is
(b) Explain Stefan–Boltzmann law of thermal radiation and Kirchoff’s law of thermal radiation.
15. (a) Explain the raw materials used, manufacturing method and properties of fire clay.
(b) Explain the raw materials used, manufacturing method and properties of dolomite refractory.