All Free Chemical Engineering MCQs with Answers

• A. Reduces its thermal efficiency
• B. Is indicated by flame sting out
• C. Increases the flue gas temperature
• D. None of these

Explanation: Interpreting “air filtration” as unintended air infiltration or leakage, it introduces cold excess air into the furnace and carries heat…

• A. 250
• B. 650
• C. 850
• D. 1000

Explanation: SiC ceramic recuperators tolerate much higher temperatures than metallic units, but their higher cost becomes economical when combustion…

• A. By-product coke ovens
• B. Beehive coke oven
• C. Blast furnace stoves
• D. Soaking pits

Explanation: By-product coke ovens use regenerative arrangements to recover heat from hot waste gases and preheat the combustion air.

• A. 5
• B. 60
• C. 20
• D. 40

Explanation: Preheating combustion air to 400°C recovers a substantial part of the flue-gas sensible heat, reducing the furnace-oil requirement by…

• A. Retards the heat transfer
• B. Assists in temperature equalisation in the charge
• C. All A., B. and C.
• D. Permits the use of controlled atmosphere for the protection of stock

Explanation: A muffle separates the stock from direct flame contact, allowing a controlled protective atmosphere, more uniform temperature…

• A. Roasting
• B. Melting
• C. Reheating
• D. None of these

Explanation: Hearth furnaces are versatile units used for roasting, melting, and reheating operations.

• A. Conduction
• B. Radiation
• C. Convection
• D. Either A., B. or C.; depends on the type of furnace

Explanation: At the very high temperatures found in furnaces, heat transfer by thermal radiation increases sharply with temperature and generally…

• A. kcal/hr
• B. kcal/m3 combustion space
• C. kcal/hr/m3 combustion space
• D. None of these

Explanation: Heat-release rate measures furnace heat intensity as the heat released per unit combustion-space volume per unit time.

• A. Are lighter
• B. Have higher pressure differential between flue gas & air side
• C. Are less costly
• D. Occupy more space

Explanation: Ceramic recuperators withstand higher temperatures but require thicker, more fragile construction and often have lower heat-transfer…

• A. Occupy more space
• B. Are less costly
• C. Are of smaller size
• D. All A., B. and C.

Explanation: A regenerator requires separate refractory storage chambers or checkerwork to absorb and release heat, so it generally occupies more space…

• A. Flame temperature
• B. Flue gas volume
• C. Fuel consumption
• D. Stack loss

Explanation: Oxygen enrichment reduces the nitrogen carried into the furnace, allowing more of the released heat to raise the combustion-gas…

• A. Glass tank furnace
• B. Cupola
• C. Open hearth furnace
• D. Reheating furnace

Explanation: A cupola is a vertical shaft furnace in which solid fuel and the charge move downward, whereas glass tank, open-hearth, and reheating…

• A. Should be as low as possible i.e., 1 : 2
• B. Should be 1:1 for a batch type furnace
• C. Is the ratio of maximum to minimum permissible heat input rates
• D. Is normally much more for a continuous furnace as compared to a batch furnace

Explanation: Burner turn-down ratio is defined as the maximum permissible heat-input rate divided by the minimum stable permissible heat-input rate.

• A. All A., B. and C.
• B. Vertical
• C. Tangential
• D. Horizontal

Explanation: Pulverised-fuel burners may be arranged for horizontal, vertical, or tangential firing, depending on furnace geometry and the required…

• A. Tunnel kiln
• B. Soaking pit
• C. Rotary kiln
• D. Reheating furnace

Explanation: A soaking pit is a periodic or batch furnace: ingots are charged, heated or soaked, and then discharged.

• A. Temperature control
• B. Measurement of flue gas volume
• C. Movement of gases
• D. Pressure adjustment

Explanation: Furnace aerodynamics concerns the flow and movement of combustion gases, including mixing, circulation, and residence time.

• A. Surface area & emissivity of the stock
• B. Properties of the muffle wall (temperature, area, and emissivity)
• C. Neither A. nor B.
• D. Both A. & B.

Explanation: A muffle furnace heats the charge indirectly, so heat transfer depends on both the charge surface and emissivity and the muffle wall's…

• A. Blast furnace
• B. Glass melting tank
• C. L.D. converter
• D. Soaking pit

Explanation: A blast furnace is a vertical shaft furnace in which solids descend through zones of preheating, reduction and melting while gases rise.

• A. Soaking pit
• B. Coke oven
• C. Steam boiler
• D. Reheating furnace

Explanation: A coke oven normally uses regenerative heating, in which checker-brick chambers store and return heat, rather than a recuperator that…

• A. 50
• B. 65
• C. 85
• D. 99

Explanation: Air or fuel-gas recuperators can achieve thermal efficiencies of roughly 85 percent under favourable operating conditions.