How does a preheater work?

The purpose of the air preheater is to recover the heat from the boiler flue gas which increases the thermal efficiency of the boiler by reducing the useful heat lost in the flue gas. It also allows control over the temperature of gases leaving the stack (to meet emissions regulations, for example).

What is APH boiler?

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. Air Pre heater’s primary objective is to extract the waste heat from the flue gases leaving the boiler.

What is the location of air preheater?

In Air Preheater (APH) heat from flue gases is absorbed for pre heating air in such a way that required stack temperature is achieved. Therefore, Air preheater of boiler is located between economizer and chimney.

What is the difference between economizer and air preheater?

economizer requires lesser space and surface area compared to the air heater due to the high tube side water heat transfer coefficient and larger U compared to the air heater. NOx formation is much more with an air heater due to the higher combustion temp with air preheat.

Why air pre-heater is used in boiler?

Air Pre-heaters are basically heat-exchangers installed in the exit flus gas duct of the boiler. The purpose of the air preheater is to recover the heat from the boiler flue gas which increases the thermal efficiency of the boiler by reducing the useful heat lost in the flue gas.

What are pre heaters?

Preheater is a general term to describe any device designed to preheat the combustion air used in a fuel-burning furnace for the purpose of increasing the thermal efficiency of the furnace. The combustion air preheaters are used for the large fuel-burning furnaces used to generate steam in thermal power plants.

What is injector in boiler?

injector, a device for injecting liquid fuel into an internal-combustion engine. The term is also used to describe an apparatus for injecting feed water into a boiler. Boiler feed water injectors employ a high-velocity steam jet to force water into the boiler.

What is Raph in boiler?

The regenerative air preheater is used in a boiler plant to extract heat from the waste flue gas and supply that heat energy to the atmospheric air that enters inside the boiler. In order to minimize that heat fluctuation, preheater is used.

Why is air pre heater used in the boiler?

Why do we reheat steam?

The quality of steam at the exit of the turbine is improved by reheating i.e. x 4s > x 4’s, so blade erosion reduces because water droplets in exhaust become less. It may also be noted that as the reheat pressure decreases, the quality of steam in a turbine exhaust (x 4) increases.

Why superheater is used in boiler?

In a steam engine, the superheater re-heats the steam generated by the boiler, increasing its thermal energy and decreasing the likelihood that it will condense inside the engine. Superheaters increase the thermal efficiency of the steam engine, and have been widely adopted.

What is the function of economiser and air preheater?

Air Preheaters Similar to economisers, they are devices that transfer heat from one surface to another – but this time from fluid to air. The main objective is to increase the thermal efficiency of a boiler system by recovering the heat from the flue gas and using it to heat the air.

What is a steam coil air pre heater?

Steam Coil Air Pre Heater (SCAPH) is an extended surface type heat exchanger. This equipment is used to heat atmospheric air to the required process temperature by means of saturated steam.

What is a steam air heater?

A Steam Air Heater (also referred to as Steam Coil Air Heaters) consists of a frame which houses one or more steam coils. The frame is installed in ducting and each steam coil is individually removable from the frame so that they can be cleaned, repaired, or replaced without disturbing the ducting.

What is the use of a steam pipe heater?

This equipment is used to heat atmospheric air to the required process temperature by means of saturated steam. Steam flows inside the tube while air passes over the finned tubes .It is generally used for heating process air in Sugar Mills, Starch Mills, Chemical & allied Industries.

Why choose rotary regenerative air preheaters?

Rotary regenerative air preheaters have a much reduced size and cost relative to recuperative tubular or plate heat exchangers. Howden’s air preheaters are engineered to meet the demands of your application. We manufacture our air preheaters in modern facilities based around the world and produce bisector, trisector and quadsector arrangements.