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Types of air preheaters and its advantages?
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Index

• What is Air preheater
• Types of air preheaters
• Regenerative or Tubular type
• What do you mean? Regenerating or feeding, giving
  water
• Advantages of Air Preheater

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Air Preheater
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What is air preheater

• An air preheater (APH) is a General term to
  describe any device, the air before another
  process is heated (e.g., combustion in a boiler)
  with the main objective to improve the thermal
  efficiency of the process.

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• Air pre-heating can increase boiler efficiency
  and reduce chimney loss. They can be used alone
  or replace a heat recovery system or replace the
  Steam coil.
• An air preheater (APH) is a device used in steam
  boilers to transfer heat from the flue gases to
  the combustion air before it enters the oven.
• Air preheater recovers the heat from the boiler
  flue gas and increases the thermal efficiency of
  the boiler .
• The flue gases are fed into the combustion gas
  stack at a lower temperature to control the
  temperature of the gases.

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• The combustion air preheaters are used in large
  boilers in thermal power plants to generate
  electricity from such fossil fuels, biomass or
  waste.
• The purpose of the air preheater heat recovered
  from boiler flue gases that increase the boiler
  thermal efficiency by reducing the useful heat
  lost in flue gases.
• As a result, the flue gas is also sent to the
  stack flue gas(or chimney) at lower temperatures,
  making simplified construction of duct and
  exhaust stack.
• It also allows control over the temperature of
  the gas leaving the stack (to meet emissions
  regulations, for example,)

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Types of air preheaters

• There are two basic types Of air preheaters
• Rec recuperative or tubular typert

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1. Regenerative or Tubular type

• Recuperative type of air Preheaters is preferably
  used in small and medium boilers. In this type,
  the heat energy exchange is carried out through
  the walls of the heating surface, which separate
  the heat energy carrier and the air to be heated.
• The ambient air is pressed by a fan through the
  conduit at one end of the preheater tube and at
  the other end, the heated air from the interior
  of the tubes into another set of conductive tube
  Preheaters out of straight bundles of tubes
  passing through the exit line of the boiler and
  open at each end outside the conduit.

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• The hot furnace gases go around the preheater
  pipes inside the pipe, which transfers that it
  carries into the furnace of a boiler for
  combustion.
• http//www.maniks.com/manufacturer/air-preheater/

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2. What do you mean? Regenerating or feeding,
giving water

• In feed water preheaters, the exchange of heat
  energy is effected by alternating heating and
  cooling of metallic or ceramic nozzles of the
  solid or rotating heating surfaces. Regenerative
  air Preheaters are compact and can have a
  stationary Rotary hood.
• Combined use of recuperative and regenerative
  type
• The applications of very high capacity boilers
  used a combination of tubular and regenerative
  type of air preheater.

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• For such applications, the primary air heating is
  carried out by tubular type and the secondary air
  heating is carried out by regenerative type.
• If the boiler designers do not want to use the
  combination of recuperative and regenerative air
  preheater, they can go for the tri-sector
  regenerative air heater.

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Advantages of Air Preheater

• For heating the air it uses heat energy of flue
  gases hence there are many more advantages of Air
  preheaters over the normal preheaters such as
• Increases thermal efficiency of the system
• Payback period is very short and increase
  combustion rate
• Improve and strengthen the combustion
• Reduces the loss of furnace and the exhaust gas
  temperature, improve the boiler thermal
  efficiency.

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• Air preheater is suitable for all standard fuels
• They are easy for retrofit into existing systems
• These air preheaters are suitable for all waste
  heat boiler / flue gas boiler / boiler types.
• They strengthen the heat transfer
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• http//www.maniks.com