All Free Chemical Engineering MCQs with Answers

• A. Before the I.D fan
• B. After the I.D. fan
• C. Near the top of the chimney
• D. Anywhere after the I.D. fan

Explanation: The damper is placed on the furnace side of the induced-draught fan so it can regulate flue-gas flow and furnace pressure before the fan…

• A. Electric arc struck between electrodes and the charge
• B. Flow of current through a heating element
• C. Combination of induced current and skin effect
• D. None of these

Explanation: In a resistance furnace, electrical resistance converts the current flowing through a heating element into heat, which is then transferred…

• A. Low emissivity
• B. High thermal conductivity
• C. Both A. and B.
• D. Neither A. nor B.

Explanation: High thermal conductivity allows heat to penetrate the stock rapidly, while low emissivity reduces the importance of radiative surface…

• A. Soaking pit
• B. None of these
• C. Reheating furnace
• D. Muffle furnace

Explanation: A muffle furnace heats the charge indirectly through a separate refractory chamber, so combustion gases or the heating elements do not…

• A. Cold rolled steel coil annealing
• B. Open hearth
• C. Soaking pit
• D. Walking beam reheating

Explanation: Cold-rolled steel coils are annealed in a controlled neutral atmosphere to prevent oxidation and preserve the required surface finish.

• A. 15
• B. 40
• C. 70
• D. 85

Explanation: A walking-beam slab-reheating furnace typically has a thermal efficiency near 40 percent, with the remainder lost through exhaust gases…

• A. Combination of induced current and skin effect
• B. Induction and resistance
• C. Current flow through a heating element
• D. None of these

Explanation: In a low- or standard-frequency induction furnace, the alternating magnetic field induces currents in the charge, and the electrical…

• A. Radiation
• B. Convection
• C. Conduction
• D. Cannot be predicted

Explanation: At about 1250°C, the radiative heat-transfer rate is dominant because it varies approximately with the fourth power of absolute…

• A. Waste heat recovery from flue gas
• B. Minimising heat losses from furnace walls
• C. Maintaining proper draught
• D. All A., B. and C.

Explanation: Furnace efficiency increases when useful heat is recovered from flue gases, wall losses are reduced by insulation, and draught is properly…

• A. Ostwald chart
• B. Cox chart
• C. Sankey diagram
• D. None of these

Explanation: A Sankey diagram represents the quantities in a heat or energy balance by bands whose widths are proportional to the quantities.

• A. Coke ovens
• B. Open hearth furnace
• C. Neither A. nor B.
• D. Both A. & B.

Explanation: Regenerators store heat from outgoing hot gases and return it to incoming combustion air or gas.

• A. All A., B. and C.
• B. Calcining
• C. Roasting
• D. Smelting

Explanation: A shaft furnace is a vertical furnace used for processes in which solids move downward through a hot gas stream, including smelting…

• A. Ingots
• B. Slabs
• C. Steel coils
• D. Steel sheets

Explanation: A pusher-type reheating furnace continuously pushes steel slabs through heating zones before rolling.

• A. 80
• B. 130
• C. 180
• D. 250

Explanation: Sulphur in the fuel forms sulphur oxides, mainly SO₂ with some SO₃, and the resulting sulphuric-acid vapour condenses at an acid dew point…

• A. 100% H2
• B. 5% H2 + 9% N2
• C. 100% CO
• D. 95% N2 + 5% H2

Explanation: Annealing steel coils requires a reducing, non-oxidising protective atmosphere, commonly nitrogen diluted with a small amount of hydrogen.

• A. All A., B. and C.
• B. Damper
• C. Variation in the pitch of fan blades
• D. Speed of the fan

Explanation: Fan-produced draught can be adjusted by changing fan speed, throttling with a damper, or varying blade pitch in a controllable fan.

• A. Regenerator
• B. Ceramic recuperator
• C. Metallic recuperator
• D. None of these

Explanation: Metallic recuperators lose strength and oxidation resistance at very high temperatures, whereas ceramic recuperators can withstand…

• A. Arc
• B. Resistance
• C. High frequency induction
• D. Low frequency induction

Explanation: High-frequency induction furnaces heat through induced currents concentrated near the surface because of the skin effect.

• A. 5
• B. 20
• C. 50
• D. 80

Explanation: Open-hearth furnaces have substantial heat losses through flue gases, walls, openings, and incomplete heat recovery, so their overall…

• A. By-product coke oven
• B. Calcination kiln
• C. Sintering furnace
• D. Open hearth furnace

Explanation: A by-product coke oven heats coal indirectly through hot combustion gases flowing in side flues, rather than firing the charge directly.