Introduction

Steam boiler or simply a boiler is basically a closed vessel into which water is heated until the water is converted into steam at required pressure. This is most basic definition of boiler.
The basic working principle of boiler is 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 the turbine of 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.
There are mainly two types of boiler that are 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 two types of boiler but each of the types can be sub divided into many which we will discuss later.

Fire tube boiler
As is indicated from the name, the fire tube boiler consists of numbers of tubes through which hot gasses are passed. these hot gas tubes are immersed into 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 same vessel. As the water and steam both are in same vessel a fire tube boiler cannot produce steam at very high pressure. Generally it can produce maximum 17.5 kg/cm2 and with a capacity of 9 Metric Ton of steam per hour. Type of fire tube boiler * Horizontal return tubular boiler. * Short fire box boiler. * Compact boiler.

Water tube boiler A water tube boiler is 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. Types of water tube boiler are * Horizontal Straight Tube Boiler : * Longitudinal Drum Water Tube Boile * Cross Drum Water Tube Boiler * Cyclone Fired Boiler. * Bent Tube Boiler

The advantage and disadvantage

Type of Boiler | Fire tube boiler | Water tube boiler | Advantage | It is quite compact in construction. | Larger heating surface can be achieved by using more numbers of water tubes. | | Fluctuation of steam demand can be met easily. | Due to convectional flow, movement of water is much faster than that of fire tube boiler; hence rate of heat transfer is high which results into higher efficiency. | | It is also quite cheap. | Very high pressure in order of 140 kg/cm2 can be obtained smoothly. | Disadvantage | As the water required for operation of the boiler is quite large, it requires long time for rising steam at desired pressure. | The main disadvantage of water tube boiler is that it is not compact in construction | | As the water and steam are in same vessel the very high pressure of steam is not possible. | Its cost is not cheap.

| | The steam received from fire tube boiler is not very dry. | Size is a difficulty for transportation and construction. |

Objective of this learning

* Describe source of energy and type of power plant source of energy * Analyze different type of steam cycle and estimate efficiencies in a steam power plant * List type, principle of operations, components and applications of steam turbines, steam generators condenser, feed water and circulating water system. Estimate different efficiencies associated with such system.

Conclusion

The steam boiler has been know by other person. There are many type of boiler and it function is also know by many people. The boiler is source of energy to move other component to do work. Without boiler, the other component cannot work because of no energy. The boiler is more efficiency than using fuel burning to give energy. It also cheap and can be renew it source and also environment save.

|