Free Plant Design and Economics MCQs with Answers

• A. Superduty fireclay
• B. Carborundum
• C. Silica
• D. High alumina

Explanation: The lower part of a hot-metal mixer faces intense abrasion and contact with molten metal, so silicon-carbide-based carborundum bricks are…

• A. Soaking pits
• B. Reheating furnace
• C. L.D. converter
• D. Rotary lime kiln

Explanation: The LD converter consumes a very large tonnage of refractory because its working lining is exposed directly to molten steel, oxygen…

• A. 10
• B. 15
• C. 20
• D. 30

Explanation: During firing, removal of chemically combined water, volatile matter, and pore-forming constituents can produce substantial volume…

• A. Acidic in nature
• B. Neutral in nature
• C. Having higher RUL than silica bricks
• D. Made by mixing 30% Chromite and 70% Periclase

Explanation: Chrome-magnesite bricks have a high resistance to softening under load, or RUL, and therefore outperform silica bricks in many…

• A. 45
• B. 60
• C. 80
• D. 95

Explanation: Silica bricks used in coke-oven walls are highly silica-rich, normally containing about 95% SiO₂.

• A. 20°
• B. 40°
• C. 60°
• D. 80°

Explanation: Conical vessel bottoms commonly use an apex angle of about 60°, which provides effective drainage without making the cone excessively deep…

• A. Takes 2-3 days for coking of coal but requires no external fuel for heating
• B. Facilitates by-products recovery
• C. Gives larger yield of coke (around 85%) as compared to by-product ovens
• D. Produces coke with very poor strength

Explanation: A beehive oven is a non-recovery coke oven: coal is coked for roughly 2 to 3 days, and the volatile gases burn inside the oven…

• A. Fuel cost per unit power generated is less
• B. Thermal efficiency of the former is higher
• C. Maintenance cost of the former is less
• D. None of these

Explanation: Nuclear fuel contains vastly more energy per unit mass than coal, so fuel cost per unit of electricity is much lower even though nuclear…

• A. Silica
• B. Silicon carbide
• C. Chrome or magnesite
• D. Low duty fireclay

Explanation: Chrome or magnesite bricks are basic, high-temperature refractories that resist attack by molten slag and scale in the lower wall courses…

• A. Coke ovens
• B. Muffle furnaces
• C. Regenerators
• D. Insulation

Explanation: Insulating refractories are selected for low thermal conductivity so they reduce heat loss through furnace walls.

• A. Graphite
• B. Magnesite chrome
• C. Silica
• D. Magnesia

Explanation: Graphite is generally classified as a neutral refractory because it is not appreciably attacked by either acidic or basic slags under…

• A. Refractoriness
• B. Spalling resistance
• C. Refractoriness under load (RUL)
• D. None of these

Explanation: Spalling resistance is the ability of a refractory to withstand cracking or flaking caused by sudden temperature changes.

• A. Diameter of Horton sphere is normally 6 to 25 metres and it is supported by 6 to 12 nos. tubular or rolled section column
• B. Thickness of spherical shell is half that of the cylindrical vessel under same operating pressure condition. Besides, the ratio of surface area to volume is less for sphere than any other shape; hence insulation required is less
• C. Horton sphere is used for the storage of liquid at sub-zero temperature at very high pressure upto 200 kg/cm2
• D. Horton sphere is used for the storage of gases and volatile liquid at a moderate pressure of 1 to 10 kg/cm2

Explanation: Horton spheres store liquefied gases or volatile liquids at moderate pressure, commonly near ambient temperature.

• A. 0.60-0.90
• B. 0.5-0.65
• C. 0.75-0.85
• D. 0.15-030

Explanation: A propeller is a high-speed agitator, so its diameter is kept relatively small compared with the tank diameter.

• A. Bending
• B. Deformation
• C. Shear
• D. Elongation

Explanation: Thin-shell analysis assumes the load is carried mainly by membrane stresses distributed through the wall.

• A. Equal to
• B. More than
• C. Less than
• D. Either B. or C.; depends on maximum permissible internal pressure

Explanation: For the same diameter, pressure and allowable stress, a cylindrical shell needs t = pD/(2σ), whereas a spherical shell needs t = pD/(4σ).

• A. Only if the opening is on spherical vessel
• B. Only if the opening is on a vertical cylindrical vessel
• C. Irrespective of the shape of the vessel
• D. Only if the opening is on a horizontal cylindrical vessel

Explanation: Under the area-compensation rule, the reinforcement pad replaces the material removed by the opening, provided it has suitable material…

• A. Pitch
• B. None of these
• C. Back pitch
• D. Margin

Explanation: The edge distance measured from a rivet-hole centre to the nearest plate edge is called the margin.

• A. 1.5 d
• B. d
• C. 0.5 d
• D. 2.5 d

Explanation: A margin of about 1.5d provides enough plate width outside the rivet hole to prevent the edge from tearing away, where d is the rivet…

• A. Expansion joint
• B. Changes in its direction
• C. All A., B. and C.
• D. Change in the shape of pipeline

Explanation: Thermal expansion can be absorbed by expansion joints, bends or direction changes, and deliberately flexible pipeline shapes such as…