Boiler operation market heating boiler air preheater aph in boiler

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

Working of Air Preheaters(APH)

1. 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.

2. 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.

Air Preheaters(APH) Brief Introduction

1. Air Preheaters (APH) is 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. Its primary objective is to extract the waste heat from the flue gases leaving the boiler.

2. Dehai Boiler Company manufacture Air Preheaters and are given as a standard side accessory along with the main equipment – Boiler, in a Packaged Type Boiler, Combi Boilers.

Tubular type Air Preheater

1. Tubular preheaters consist of straight tube bundles which pass through the outlet ducting of the boiler and open at each end outside of the ducting.

2. Inside the ducting, the hot furnace gases pass around the preheater tubes, transferring heat from the exhaust gas to the air inside the preheater.

3. Ambient air is forced by a fan through ducting at one end of the preheater tubes and at other end the heated air from inside of the tubes emerges into another set of ducting, which carries it to the boiler furnace for combustion.

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