Boiler Components

Boiler Burners

The Burner of the Boiler is the source of heat in boilers which are powered by natural fuel such as gas or oil.  It is the place where the fuel is burnt to produce energy.

The burners in Boilers should combust the fuel with very low emissions.  They are sometimes provided with an air source such as a fan to ensure proper combustion with little residue.

Duel Fuel burners can burn both oil and gas.  Common fuels are Furnace Oil, Light Oil, Natural Gas and Liquefied Petroleum Gas. 

Boiler Burners can range in capacity from 200 kW to 15000 kW

Modern Burners in Boilers have sophisticated electronic controls which algorithms for precise air-fuel mixtures for optimum efficiency. 


Economizer in Boilers

The Economizer in a boiler is used to preheat the water which is fed into the boiler by using the exhaust gases of the boiler.  In this way, it is able to "economize" or save energy.  The heat of the exhaust gases will be in the range of 380 to 550 degrees Celsius.  By utilizing this heat energy, the economizer increases the overall efficiency of the boiler. 

The Economizer is in the form of vertical tubes in which the water flows.  The gases on the way to the exhaust stack transfer their heat to the economizer.  The temperature of the inlet water to the economizer should not be too low as that can result in fouling and corrosion. 

The outlet temperature of the economizer is also below the boiling point of the water.

Shell of the Boiler

The Shell of the boiler refers to the body of the boiler.  The Shell is made up of steel plates which have been rivetted  or welded together. 

The end plates are at the top and the bottom of the shell. 
The Shell is designed to withstand high pressure and temperature.  It is also designed to resist corrosion. 


Membrane Contactors in Boilers

Membrane Contactors are used to deaerate water in a boiler.   Membrane Contactors are getting increasingly popular.  Membrane Contactors use a membrane which is made of hydrophobic material with pore size of the order of 0.03 micrometer.

On one side of the membrane, a gas, usually nitrogen,  is passed at low pressure.  On the other side, the water to be deaerated is passed.  Since the membrane is hydrophobic, the water does not pass through it.  But the gases which are dissolved pass through the membrane to the other side with low pressure. 

The deaeration process can be controlled by varying the pressure of the gas and its concentration. The capacity of the contactor can be increased by adding more membranes. The membrane contactor method can produce water with a dissolved oxygen concentration of less than 1 ppb (parts per billion).

The advantages of using Membrane Contactors are
  • Absence of Emulsions
  • No Flooding even at high flow rates.
  • No density difference between the fluids is required.
  • High surface areas

Vacuum Pumps

Vacuum Pumps are used in Boiler Systems to evacuate the air from the piping.  Air reduces the heat transfer and acts as a thermal insulator.  It allows impedes the flow of steam.  The Vacuum pump is used to evacuate air from the pipelines.

The gases present in the air such as oxygen and carbon dioxide can dissolve with air and cause corrosion.  Using a Vacuum pump can remove these gases and lower the dissolved gas level in the system preventing corrosion.

Once air is removed from a system and a vacuum is created, steam requires a very low pressure to flow across the system. 

Since the pressure of the system decreases, the boiling point of water also decreases.  This results in a reduction of the fuel consumption.  Vacuum pumps can also be used for lifting the condensate  to the receiver.  This is necessary to prevent water hammering.

Vacuum pumps are specified in the amount of air they can move at a given vacuum. They can produce vacuums of the range of 5, 10 and 15 inches of Hg.

Insulation in Boiler system is a critical piece of equipment.  It is factor which has a direct relationship with efficiency and cost.  Heat Energy is produced in the boiler.  This energy is transferred using steam as a medium throughout the system.

Poor or damaged insulation can also result in condensate formation which can cause problems such as hammering.

The Insulation in Boiler systems has three main functions

  • To prevent heat leakage from the boiler and the system
  • To protect personnel from accidental contact with hot surfaces.
  • To ensure a tolerable working temperature in the boiler room and surrounding for the operating personnel

There are many different materials used for Boiler Insulation. Glass Wool is a common material. Other insulation Materials are Styrofoam, fibreglass and polystyrene.

Spray On Ceramic Insulation in Boilers

Spray On Ceramic Insulation is a popular method of insulation in recent times. The insulation consists of a ceramic material which is sprayed on to the surface of the boiler and piping using a special equipment.

 Ceramic insulation is more expensive than fibreglass insulation. Once sprayed, the material solidifies into a foam type material. One advantage of this method is that it is easy to apply. The downtime required is very less.

It is lightweight and can also be easily applied to irregular surfaces and edges . Ceramic insulation is also a corrosion inhibitor. It can also withstand moisture better.

Special types of ceramic insulation can be sprayed on to the surfaces of hot equipment. This can reduce downtime.