Consider the following statements regarding "Waste Heat Recovery" (WHR):1.It involves capturing heat from industrial exhaust gases to generate steam or power.2.Economizers in boilers are a common example of WHR.3.WHR increases the carbon footprint of the industry.Which of the statements given above is/are correct?

Correct Answer: A - 1 and 2 only

Quick Concept Explanation

Waste-heat recovery captures thermal energy that would otherwise leave through exhaust gases or hot process streams and uses it for feedwater heating, steam generation, process heating or power generation. Boiler economizers are a classic example because they use flue-gas heat to preheat feedwater, reducing fuel requirement and emissions for the same useful output.

Exam focus: Economizer = flue-gas heat recovery to feedwater. Common trap: WHR generally reduces, not increases, carbon intensity.

Statement-wise Verification

• Statement 1 - Correct.
  It involves capturing heat from industrial exhaust gases to generate steam or power.
  Waste-heat recovery captures thermal energy that would otherwise leave through exhaust gases or hot process streams and uses it for feedwater heating, steam generation, process heating or power generation.
• Statement 2 - Correct.
  Economizers in boilers are a common example of WHR.
  Boiler economizers are a classic example because they use flue-gas heat to preheat feedwater, reducing fuel requirement and emissions for the same useful output.
• Statement 3 - Incorrect.
  WHR increases the carbon footprint of the industry.
  Recovering otherwise wasted heat generally reduces fuel use and emissions for the same useful output

Core Concept

Waste-heat recovery captures thermal energy that would otherwise leave through exhaust gases or hot process streams and uses it for feedwater heating, steam generation, process heating or power generation. Boiler economizers are a classic example because they use flue-gas heat to preheat feedwater, reducing fuel requirement and emissions for the same useful output.

Formula / Key Relationship

Recovered heat reduces required fuel input for a given useful energy output.

Why the Other Options Are Wrong

Option B is incorrect because it includes incorrect statement(s) 3 and omits correct statement(s) 1. Option C is incorrect because it omits correct statement(s) 2. Option D is incorrect because it includes incorrect statement(s) 3.

Exam Shortcut / Approach

Economizer = flue-gas heat recovery to feedwater.

Common Mistake

WHR generally reduces, not increases, carbon intensity.

Quick Revision

Economizer and Heat Recovery is linked with Waste Heat Recovery, Thermal Energy Efficiency and Energy Management. Economizer = flue-gas heat recovery to feedwater.