What Are Boiler Accessories?

Boiler accessories are devices and plants that are installed with boilers to improve the operating condition and overall efficiency of the boiler plant. Boiler accessories are devices that are installed along the boiler and the surrounding area to increase the efficiency of the boiler. These are not an indispensable part of the boiler, and thus without installing these devices, the boiler operation can be completed at low efficiency.

1. Feed Pump

Feed Pumps Are Used to Feed High-Pressure Water in Boilers. The Steam Pressure Inside the Boiler Is High, So the Feed Water Pressure Must Be Increased for Smooth Operation Before Reaching the Boiler. in General, the Feed Water Pressure Is 20% Higher Than the Boiler Pressure. The Feed Pump May Be of a Centrifugal or Reciprocating Type.

2. Soot Blower

During combustion, soot accumulates on the inner tubes of the furnace, and the gas passes are plugged in. Ultimately, soot deposited inside the furnace reduces the efficiency of the boiler. A soot blower is used to remove the soot from the tubes to prevent the gas pass from being plugged.

3. Injector

The function of the injectors is the same as that of the feed pumps; It is used where space is not available for the installation of the feed pump. The kinetic energy of steam in an injector is used to increase the pressure and velocity of feed water in a convergent-diverging nozzle.

Advantage of Injector

• Simplicity,
• Density,
• High thermal efficiency,
• Lack of dynamic part.

Disadvantages of Injector

• Low pumping efficiency,
• Difficulty in operation under extreme variations in steam pressure.

4. Superheater

The superheater raises the temperature of saturated steam without increasing its pressure. It consists of a small bundle of tubes. It is set in the path of the hot flue gas of the furnace. Saturated steam passes inside the heater tubes, and hot flue gases pass outside the tubes. Thus the transfer of heat takes place in saturated steam from hot flue gases and raises its temperature without increasing the pressure of steam.

For this purpose, convection superheaters and radiation superheaters are used. The change in steam temperature depends on the position of the superheater, the temperature of the hot flue gases, the configuration of the superheater, and the flow of steam. If the temperature of the saturated steam rises to 100C with the help of a superheater, then a 1 percent saving of fuel can be achieved.

Advantage of Superheater

• Steam consumption reduced.
• Protection from turbine corrosion.
• The losses from the condensation of steam in cylinders and pipes are reduced.
• Increases efficiency of plants.

5. Air Preheater

The air preheater is used to recover heat from the exhaust flue gases. It is established between the chimney and the economist. Through the preheater, air passes for combustion purposes. This increases the temperature of the combustion air with the help of exhaust flue gases. The air passes through the heater tubes, and the flue gas passes through the outside of the heater tubes.

Thus, heat is transferred from the flue gases to the air required for combustion. If the temperature of the combustion air rises to 1000F with the help of an air preheater, 2.3 to 2.6 percent of fuel can be saved. In some situations, 5% to 10% of fuel savings can also be achieved.

Advantage of Air Preheater

• The evaporative capacity per kilogram of fuel increases.
• For every 35-400C increase in air temperature, the boiler increases 2 percent of efficiency.
• It Burns better with less smoke, soot, and ash.
• Allows low-grade fuel to burn with less excess air.

6. Pressure Reducing Valve

The function of a pressure-reducing valve is to maintain constant pressure on the distribution side of the boiler regardless of its pressure.

7. Steam Separator

In turbines, the use of wet steam is unviable; Therefore, a steam separator, also known as a moisture separator, is used. The function of the steam separator is to remove water droplets from the steam. It is installed on the main steam pipe in the boiler. It is important to remove steam that is in the water because water droplets in the steam reduce thermal efficiency.

Water can accumulate in the cylinder and cause a hydrostatic lock which damages the engine. In thermal power plants, water droplets of high-speed steam from the nozzle damage the turbine blades.

According to operating principles, they are classified as Impact or Baffle Type, Reverse Current Type, Centrifugal Type.

Source From  : https://mechanicaljungle.com/