Steam boilers: Types, Parts, working principle and applications

What is the steam boilers?

• A boiler is closed cylindrical type vessel; the vessel is filled with water, applies various pressure, and then is converted to steam, called a steam boiler. Then this steam successfully transfers via pipes to desired locations such as steam engines, turbines, etc.,

Purpose of steam boiler:

• To create the power for steam engines and turbines.

• To use steam in various process industries.

• The steam will be used to heat the living room during cold times.

Components of steam boilers:

1). Water drum:

• A water drum is cylindrical and filled with water. The water is treated to a different temperature and then released steam. Generally, this water drum is fitted on the ground floor.

2). Steam drum:

• The steam drum is attached to the water drum. This steam drum helps to store the steam coming out of the water drum and then take it to the required places through the pipe.

• This steam drum and water drum have two entry points and two exit points. During maintenance, need to work inside the drums requires confined space and it attached with work permit because there are many hazards available for inside both drums.

3). Economizer:

• An economizer is another type of heat exchanger. Its purpose is to preheat the water from the boiler feed water pump and then send it to the boiler.

• The energy generated in the boiler's water-to-steam process is reduced as the preheated water is sent to the boiler.

4). Furnace:

• The furnace plays an essential role in the steam generation process by generating heat energy. It converts water into steam by providing the required amount of heat and also acts as a combustion chamber when the fuel burns.

5). Burner:

• A burner is a device used for the combustion process in the boiler. It is used to control the flow of fuel and ensure combustion. As a result, a good amount of heat is produced. It comes in three different types these are;

a). Gas burners:

• These burners operate with Only LPG (Liquified petroleum gas) and LNG (Liquified petroleum gas).

b). Oil burners:

• These burners operate only light and heavy duty oils.

c). Combined burners:

• This is for gas and oil burners. These types of burners operate with oil and gases.

6). Heat exchanger:

• A boiler heat exchanger transfers the heat from combustion gases to water. Generally, heat exchangers have two types these are,

1. Shell and tube heat exchanger

2. Plate heat exchanger

a). Shell and tube heat exchanger:

• In this, heat exchangers have cylindrical shapes and shells filled with tubes. Combustion gas flow through the shells, and water flows through the tubes and absorbs heat.

b). Plate heat exchanger:

• The heat exchanger has rectangular plates on one side of the hot surface and the other side of the cold surface. The hot surface allows combustion gas to pass through it, and the cold surface allows water to pass through it and exchange the heat through this process.

Working principle of steam boiler:

• A boiler is a closed vessel with a cylindrical shape. When the fuel is burned, it produces hot combustion gas with the help of a furnace. The hot gases directly contact the water drum to transfer the heat to water. The boiler has two bigger drums: one is the water drum, which is fully filled with water, and another is the steam drum. When the heat is transferred to the water, the water is heated and produces steam; this produces steam stored in the steam drum. Generally, the two drums are in direct contact with each other. Then, these steam drum piping connections transferred the steam to the required places to plants.

Types of steam boilers:

Steam boilers are classified into many types. These are,

a). Water tube boilers:

• Water tube boilers produce steam heavily. In these boilers, water flows through the tubes, and the gases flow around the tubes. Water tube boilers are more efficient in producing steam than fire tube boilers.

b). Fire tube boilers:

• Fire tube boilers burners release fire with the help of fuels. This released fire heats water, which flows through the tubes surrounded by hot combustion gases and than produces steam.

c). Electric steam boilers:

• Electric steam boilers have electric coil heaters instead of burners. These coil heaters heat the water and then produce steam. Generally, this type of boiler is used in small-scale applications like hospitals, food processing industries, etc.,

d). Low and high-pressure steam boilers:

• Low-pressure steam boilers can produce a pressure range of 10 to 15 psi and a temperature range of 149°C. They require a constant temperature to work.

• High-pressure steam boilers can produce a pressure range of 15 to 800 psi and a temperature range of over 121°C. They can create excellent steam at high pressure, which is why it is used for equipment and machinery.

e). Gas boilers:

• Gas boilers work with natural gas or propane fuel. These steam boilers are more efficient than other types of steam boilers. The fuel source in these boilers comes via external pipelines, which are directly attached to the boiler. These boilers are used in industrial and low-applications.

Applications of steam boilers:

• To produce the power to steam turbines in oil and gas industries.

• To heat the houses and buildings in cooling climates.

• These are used in various industries and applications.

• These are used in hospitals to clean the equipment and heat the water.