B. Thick firebed and preheated primary air

C. Low reactivity of carbonised residue containing high proportion of iron & sulphur

D. Low forced draft & fuel bed temperature

A. 80

B. 65

D. 20

B. Melting

C. Reheating

D. Roasting

A. None of these

B. Natural convection

C. Conduction

A. Resistance

B. Arc

C. Induction

A. To increase heat transfer by convection

C. To ensure uniform temperature

D. In furnaces, operating below 750C

B. Furnace oil

C. Combustion air

D. Pulverised coal

A. Less erosion on furnace wall

C. Smokeless burning

D. Higher calorific value

A. 60

B. 5

C. 40

A. Steam superheater

B. Air preheater

D. Economiser

A. Either A., B. or C.; depends on the type of furnace

C. Conduction

D. Convection

B. Ostwald chart

C. Cox chart

D. None of these

A. Ammonia

B. Fine dolomite

D. Alkaline powders

A. Low frequency induction

B. None of these

C. Resistance

A. Open hearth furnace

B. Soaking pit

D. Reheating furnace

A. Permits the use of high ash content coal

C. All A., B. and C.

D. Permits the use of low fusion point ash coal

A. CO

B. H2

D. High CO/CO2

A. Minimising heat losses from furnace walls

B. Maintaining proper draught

D. Waste heat recovery from flue gas

A. Coke oven heating chamber

B. Open hearth furnace

D. Neither A. nor B.

A. Should be 1:1 for a batch type furnace

C. Is normally much more for a continuous furnace as compared to a batch furnace

D. Should be as low as possible i.e., 1 : 2

B. Sidefired

C. Recirculating

D. Covered

B. Scope of reduction of heat losses

C. Sources of heat losses

D. Thermal efficiency of the process

A. Calcination kiln

C. Sintering furnace

D. Open hearth furnace

A. Permits the use of controlled atmosphere for the protection of stock

B. Retards the heat transfer

D. Assists in temperature equalisation in the charge

A. Flue gas temperature

B. Emissivity of refractory walls

C. Initial temperature of the charged stock

A. Addition of methane to the furnace atmosphere reduces decarburising by hydrogen

C. Active nitrogen (formed by cracking ammonia at the metal surface) cause nitride formation

D. h increase in surface hardness

E. burise the surface of steel at annealing temperatures

F. Nitrogen in presence of steam decor-burises high carbon steel, whereas hydrocarbon gases

B. The fan operates hot and hence blades are liable to corrosion and erosion

C. None of these

D. Air is sucked in, so air leaks are more and hence the furnace efficiency is reduced

A. Coke ovens

C. Annealing furnace

D. None of these

A. Ostwald chart

C. None of these

D. Cox chart

A. Tar content in producer gas

B. Temperature of producer gas

D. C. V. of producer gas

A. Use of coal/coke containing a high % of fines and ash

C. Development of hot spots in the fuel bed and an abnormally high rate of gasification

D. Use of fuel having too low an ash fusion temperature

A. Is indicated by flame sting out

B. None of these

D. Increases the flue gas temperature

A. Variation in the pitch of fan blades

C. Damper

D. Speed of the fan

B. Ton stock/hr

C. Ton stock/m2 hearth area

D. Both B. and C.

A. Tunnel kiln

B. Walking beam reheating furnace

D. Tower furnace

A. Minimum heat input rate only

C. Maximum heat input rate only

D. Volume of the combustion chamber

A. Oxidation/scaling

C. Decarburising

D. Sulphur penetration

A. After the I.D. fan

C. Near the top of the chimney

D. Anywhere after the I.D. fan

A. < 8

C. < 10

D. < 5

B. 80

C. 5

D. 50