3284. silicon carbide refractories have very low
refractoriness (< 1700°C).
thermal conductivity.
resistance to thermal shock.
none of these.
✅ The correct answer is option D.
3289. Incomplete combustion of fuel in the furnace is judged by high __________ of the flue gases.
CO content
Dew point
CO₂ content
O₂ content
✅ The correct answer is option A.
3294. Refractory castables are used for
producing monolithic linings.
patch work.
minimising the number of joints in the structure.
all (a), (b) and (c).
✅ The correct answer is option D.
3299. Presence of __________ in a dry gaseous fuel does not contribute to its calorific value.
Sulphur
Oxygen
Hydrogen
Carbon
✅ The correct answer is option B.
3304. Chrome magnesite is not used in the
inner lining of L.D. converter.
aluminium melting furnaces.
wear out lining of steel melting furnaces.
all (a), and (b) and (c)
✅ The correct answer is option C.
3310. The maximum adiabatic flame temperature in air as compared to that in pure oxygen is
Much lower
Much higher
Same
Either lower or higher, depends on the type of fuel
✅ The correct answer is option A.
3320. Stoichiometric combustion of 12 kg of carbon requires __________ of oxygen.
1kg mole
22.4 Nm³
32 kg
All of the above
✅ The correct answer is option D.
3229. Fuel gases containing hydrocarbons (ie.g. coke oven gas) are not preheated before burning, mainly because
The hydrocarbons crack thereby choking and fouling the heat transfer surface by carbon soot
It reduces its calorific value tremendously
It reduces its flame temperature tremendously
There are chances of explosion during preheating
✅ The correct answer is option A.
3234. Which of the following is not a by-product recovered in a high temperature coal carbonisation plant?
Benzol
Pitch-cresosote mixture (PCM)
Napthalene
Ethylene
✅ The correct answer is option D.
3239. L.D. converter gas (produced in steel plant) comprises mainly of
CO (upto 65%) & CO₂
CO₂ & H₂
CO & O₂
CO₂ & O₂
✅ The correct answer is option A.