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What is the purpose of air preheater in boiler?

What is the purpose of air preheater in boiler? Correct Answer To increase air temperature by flue gases

Explanation:

Air Preheaters:

  • An air preheater uses energy left in flue gases that leaves the boiler to preheat the combustion air. This makes the air preheater the only true heat trap because it does trap the heat without adding any surface to the boiler.
  • The way air preheater increases the efficiency of the boiler is by raising the temperature of the combustion air using the slack heat of flue gases instead of fuel.
  • There is also a slight increase in the heat flow through the boiler heating surface due to higher furnace temperature.
  • An advantage of air heaters is higher temperature differentials.

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