What is Air Preheaters in Boiler ( APH) Working, Function & Types

 What is Air Preheaters (APH)

Air Preheaters (APH) are the Shell and tube type Heat Exchangers used for preheating the air which is fed to the boiler or furnaces/kilns for combustion of fuels. The Air Pre heater’s primary objective is to extract the waste heat from the flue gases leaving the boiler.

Thermodyne Engineering Systems manufacture Air Preheaters which are given as a standard side accessory along with the main equipment – Boiler, in a Packaged Type Boiler, Combi Boilers.

What is the function of the air preheater?

The main function of an air preheater is to increase the thermal efficiency of a boiler by preheating the combustion air using waste heat from the flue gases. This process improves combustion rates, combustion efficiency, and overall boiler efficiency.

 

Air Pre Heater (APH)

Air Pre heater in Boiler

Air preheaters are devices used in boilers to heat the combustion air before it enters the boiler. This process improves the thermal efficiency of the boiler system by reducing the amount of fuel required to achieve the desired temperature.

Benefits of using an air preheater:

Applications of air preheaters:

What is the function of the air preheater in boiler ?

An air preheater is a crucial component in boiler systems, primarily responsible for enhancing the boiler’s efficiency. It achieves this by preheating the combustion air before it enters the boiler furnace, leading to several benefits:

  • Reduced fuel consumption: Preheating the combustion air significantly reduces the amount of fuel needed to reach the desired boiler temperature. This translates into lower fuel costs and a more environmentally friendly operation.

  • Improved combustion efficiency: By supplying preheated air, the combustion process becomes more efficient, leading to a more complete fuel burn. This results in higher heat release and better overall boiler performance.

 

Why is hot air sent to the furnace?

For generating fire in a boiler furnace 3 main ingredients are needed: Fuel, Air & Ignition. Air is used in a Boiler for the combustion of fuel. Based on the stoichiometry calculation, the right quantity of air along with excess air is fed into the boiler furnace for the combustion of fuel.

Generally, fuel fed to the boiler is at normal room temperature, and for the combustion of fuel to take place; the temperature of the fuel is increased from its room temperature to ignition temperature. So to increase the efficiency of the combustion process as well as a boiler, hot air is fed to the furnace for the combustion of fuel.

Type of Air Preheaters (APH)

We manufacture different types of air preheaters:-

Working of Air Preheaters(APH)

Air Preheaters have a shell and tube type construction where exhaust heat from the flue gases is transferred to the air when they come in indirect contact with each other.

Air Preheaters consist of a shell where tubes are arranged in a square or triangular pitch and are welded to a tube plate. Depending upon the type of operation and ease of cleaning, flue gases & air can be allowed to travel either shell side or tube side interchangeably.

Also Read: What is Combi Boiler?

Thermodyne Boilers finned tube air preheaters are designed to maximize efficiency by increasing the heating surface area without increasing the space requirement.

Thermodyne Engineering Systems manufacture air preheaters that are tailor-made to suit the customer’s requirement.

Our Air Preheaters are designed in both 1 and 2 passes for both flue gases and air to extract maximum heat from the flue gases.

Thermodyne Boilers manufacture air pre-heaters for a wide capacity range and can satisfy the various fuel requirements of a customer such as:

  • Wood
  • Coal
  • Husk
  • Bagasse
  • Petcoke
  • Light Oil and Heavy Oil

Air Preheater Pros:

  • 2 pass design to extract maximum waste heat from flue gases leaving the boiler.
  • It is used to extract waste heat from the flue gases leaving the boiler exhaust thereby increasing the efficiency of a boiler by 2-3 %.
  • It is used to preheat the fuel which further increases the boiler efficiency.
  • Payback time is less.

Air Preheater Cons

  • Adding equipment or accessory in the path of flue gases increases flue gas pressure drop down the line, so the size of the Induced Draft Fan increases.

Buy Air Preheater from Indian Manufacturer: Thermodyne Engineering Systems: Contact Us

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What is an APH?

An APH is a heat exchanger that is used to preheat the air that is used to burn fuel in a boiler. This preheating increases the efficiency of the boiler by reducing the amount of fuel that is needed to heat the air.

What are the different types of APHs?

There are two main types of APHs: recuperative and regenerative. Recuperative APHs use a single heat exchanger to transfer heat from the flue gases to the air. Regenerative APHs use a series of heat exchangers that are alternately exposed to the flue gases and the air.

What are the advantages of using an APH?

There are several advantages to using an APH, including:

What are the disadvantages of using an APH? There are a few disadvantages to using an APH, including:

Increased cost
Increased maintenance requirements
Potential for increased corrosion

Where are APHs used? APHs are used in a variety of applications, including:

Power plants
Industrial boilers
Heating systems
Marine vessels

How does an APH work?

An APH works by transferring heat from the flue gases to the air that is used to burn fuel. The flue gases are heated by the combustion process, and they flow through the heat exchanger. The air then flows through the heat exchanger, and it absorbs heat from the flue gases. The preheated air then flows into the combustion chamber, where it is used to burn fuel.

What are the maintenance requirements for an APH?

APHs require regular maintenance to ensure that they operate properly. This maintenance includes:
Cleaning the heat exchangers
Replacing the seals
Lubricating the bearings

How long do APHs last?

APHs can last for many years with proper maintenance. However, they may need to be replaced if they become damaged or corroded.

What are the safety considerations for APHs?

APHs can pose a safety hazard if they are not properly maintained. Some of the safety concerns associated with APHs include:
Fire
Explosion
Corrosion
Toxic fumes

Where can I learn more about APHs? There are a number of resources available to learn more about APHs, including:

Manufacturers’ websites
Technical manuals
Trade publications
Professional organizations

What is an air preheater?

An air preheater is a device that heats the air before it enters a boiler. This helps to improve the efficiency of the boiler by reducing the amount of fuel that is needed to heat the water.

What are the different types of air preheaters?

There are two main types of air preheaters: recuperative and regenerative. Recuperative air preheaters use a heat exchanger to transfer heat from the flue gases to the air. Regenerative air preheaters use a rotating wheel that is coated with a heat-absorbing material. As the wheel rotates, it alternately exposes the hot flue gases and the cold air to the heat-absorbing material.

How does an air preheater work?

Air preheaters work by transferring heat from the flue gases to the air. This is done through a heat exchanger or a rotating wheel. The heated air then enters the boiler, which helps to improve the efficiency of the boiler.

What are the benefits of using an air preheater?

There are several benefits to using an air preheater, including:
Increased boiler efficiency.
Reduced fuel consumption.
Reduced emissions.
Longer boiler lifespan.

What are the common problems with air preheaters?

The most common problems with air preheaters include:
Fouling.
Leaks.
Damage to the heat exchanger or rotating wheel.

How long does an air preheater last?

The lifespan of an air preheater will vary depending on the type of air preheater and the maintenance schedule. However, most air preheaters will last for many years.

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