Skip to main content
Sign in Register
Sarkari MCQs Government Exam Question Bank
Question no. 9838

Which heat exchange device is best suited for preheating combustion air past 650°C ?

Select your answer for: Which heat exchange device is best suited for preheating combustion air past 650°C ?
Show answer

Answer: C. Ceramic recuperator

Explanation

Ceramic recuperators withstand ultra-high operating temperatures exceeding the limits of metallic alloys. Preheating combustion air past six hundred fifty degrees Celsius requires advanced heat-resistant ceramic materials. Metallic recuperators suffer from severe thermal degradation and oxidation at such high temperatures. Recuperators are heat exchangers that recover waste heat from exhaust gases to preheat combustion air. Ceramic materials offer superior refractoriness and corrosion resistance in aggressive high-temperature environments. High combustion air preheat temperatures significantly improve overall thermal efficiency in industrial furnaces.

Glass melting furnaces and steel reheating kilns utilize ceramic recuperators for waste heat recovery. Industrial energy conservation programs rely on advanced high-temperature heat exchanger technologies. Metallurgical processing plants operate high-efficiency combustion systems using ceramic heat transfer units. Regenerators store and release heat cyclically rather than serving as continuous recuperative exchangers. Metallic recuperators soften, oxidize, and fail when exposed to temperatures exceeding six hundred fifty degrees. Selecting none of these ignores the availability and specific application of ceramic recuperators.

Subject
Engineering
Category
Chemical Engineering
Topic
—
Difficulty
medium

Related questions

Engineering Chemical Engineering
medium

Q1. Given an HCl and NaOH neutralization enthalpy of – 57.46 kJ/Kg mole, the calculated heat of water ionization is _____________ kJ/Kg mole?

Select your answer for: Given an HCl and NaOH neutralization enthalpy of – 57.46 kJ/Kg mole, the calculated heat of water ionization is _____________ kJ/Kg mole?
Save
Show answer

Answer: A. 57.46

Water ionization is the exact reverse process of strong acid and strong base neutralization. Reversing a chemical reaction changes the sign of its corresponding enthalpy change value. The standard ionization heat of wate...

Engineering Chemical Engineering
medium

Q2. The thermal energy required to decompose a chemical compound into its constituents is _____________ the energy liberated during its formation?

Select your answer for: The thermal energy required to decompose a chemical compound into its constituents is _____________ the energy liberated during its formation?
Save
Show answer

Answer: A. The same

The law of conservation of energy dictates that energy cannot be created or destroyed. Decomposing a chemical compound requires the exact same energy released during its formation. Thermochemical cycle principles ensure...

Engineering Chemical Engineering
medium

Q3. A well-mixed vessel containing 1000 kg of liquid at 30°C is heated to 120°C using condensing steam coils at 150°C. With a coil surface area of 1.2 m2, overall heat transfer coefficient of 1500 W/m2.°C, negligible heat loss, and liquid specific heat of 4 kJ/kg.°C, the time needed to reach the set temperature is__________________?

Select your answer for: A well-mixed vessel containing 1000 kg of liquid at 30°C is heated to 120°C using condensing steam coils at 150°C. With a coil surface area of 1.2 m2, overall heat transfer coefficient of 1500 W/m2.°C, negligible heat loss, and liquid specific heat of 4 kJ/kg.°C, the time needed to reach the set temperature is__________________?
Save
Show answer

Answer: D. 51 min

Transient energy balances equate heat transferred from steam coils to sensible heat gained by liquid. Log mean temperature differences drive heat transfer across the submerged coil surface area. Integrating the unsteady-...

Engineering Chemical Engineering
medium

Q4. A _____________ heat exchanger is optimal when the shell-side fluid temperature significantly exceeds that of the tube-side?

Select your answer for: A _____________ heat exchanger is optimal when the shell-side fluid temperature significantly exceeds that of the tube-side?
Save
Show answer

Answer: B. U-tube

U-tube heat exchanger designs allow independent thermal expansion of individual tubes within the shell. Large temperature differences between shell-side and tube-side fluids create severe thermal stress risks. U-bend con...

Engineering Chemical Engineering
medium

Q5. A dry solid mass of 200 kg undergoes drying for 5000 seconds during the constant-rate period at Nc = 0.5 × 10-3 kg/m2.s. Initial moisture is 0.2 kg/kg dry solid with an interfacial area of 4 m2 per 1000 kg dry solid. The final moisture content (in kg moisture/kg dry solid) is?

Select your answer for: A dry solid mass of 200 kg undergoes drying for 5000 seconds during the constant-rate period at Nc = 0.5 × 10-3 kg/m2.s. Initial moisture is 0.2 kg/kg dry solid with an interfacial area of 4 m2 per 1000 kg dry solid. The final moisture content (in kg moisture/kg dry solid) is?
Save
Show answer

Answer: C. 0.1

Constant-rate drying equations relate moisture evaporated over time to drying rate and area. Multiplying drying rate by interfacial area and time yields total moisture mass evaporated. Subtracting evaporated moisture fro...

Engineering Chemical Engineering
medium

Q6. A _____________ colored paint possesses the lowest absorption coefficient?

Select your answer for: A _____________ colored paint possesses the lowest absorption coefficient?
Save
Show answer

Answer: B. White lead

White lead paint exhibits extremely high solar reflectance and minimal radiation absorption properties. Light-colored and white surfaces reflect most incident thermal and visible light radiation effectively. A low absorp...