Asteam boileris defined as a boiler use heat to convert water into steam for a variety of application.

In technical terms, A boiler can be defined as a closed vessel in which water or other fluid is heated under pressure. This fluid is then circulated out of the boiler for use in various processes or power generation. In the case of power generation steam is taken out of the steam boiler at very high pressure and temperature.

Working Principle of Boiler

The basicworking principle of the boileris very very simple and easy to understand. The boiler is essentially a closed vessel inside which water is stored. Fuel (generally coal) is bunt in a furnace and hot gasses are produced. These hot gasses come in contact with water vessel where the heat of these hot gases transfer to the water and consequently steam is produced in the boiler. Then this steam is piped to theturbine of the thermal power plant. There are many different types of boiler utilized for different purposes like running a production unit, sanitizing some area, sterilizing equipment, to warm up the surroundings etc.

Steam Boiler Efficiency

The percentage of total heat exported by outlet steam in the total heat supplied by the fuel (coal) is calledsteam boiler efficiency.

It includes thermal efficiency, combustion efficiency & fuel to steam efficiency.Steam boiler efficiencydepends upon the size of boiler used. A typical efficiency of the steam boiler is 80% to 88%. Actually, there are some losses occur like incomplete combustion, radiating loss occurs from steam boiler surrounding wall, defective combustion gas etc. Hence, an efficiency of steam boiler gives this result.

Biomass fired steam boiler

Types of Boiler

There are mainly twotypes of the boiler– water tube boiler and fire tube boiler. In fire tube boiler, there are numbers of tubes through which hot gases are passed and water surrounds these tubes. Water tube boiler is reverse of the fire tube boiler. In water tube boiler the water is heated inside tubes and hot gasses surround these tubes. These are the main twotypes of the boilerbut each of the types can be subdivided into many which we will discuss later.

Fire Tube Boiler

As is indicated by the name, thefire tube boilerconsists of numbers of tubes through which hot gasses are passed. These hot gas tubes are immersed in water, in a closed vessel. Actually, in fire tube boiler one closed vessel or shell contains water, through which hot tubes are passed. These fire tubes or hot gas tubes heated up the water and convert the water into steam and the steam remains in the same vessel. As the water and steam both are in the same vessel a fire tube boiler cannot produce steam at very high pressure. Generally, it can produce maximum 17.5 kg/cm²and with a capacity of 9 Metric Ton of steam per hour.

Water Tube Boiler

Awater tube boileris such kind of boiler where the water is heated inside tubes and the hot gasses surround them.  This is the basic definition of water tube boiler. Actually, this boiler is just opposite of fire tube boiler where hot gasses are passed through tubes which are surrounded by water.