This article provides complete answers to the following questions:

• What is a steam boiler?
• Purpose of Steam Boiler
• Types of steam boilers
• How steam boilers are made
• Uses for steam boilers

 

What is a steam boiler?

One of the most important equipment of in industrial facilities is the steam boiler, which is responsible for generating steam for industrial purposes and some facility systems.

The basic working principle involves the combustion of fuel inside the boiler’s combustion chamber, which produces high-temperature gases that transfer heat energy to the water surrounding the chamber, causing it to boil. Steam boilers come in different types, such as fire-tube and water-tube boilers, and have essential roles in providing heat and steam for various applications. Proper maintenance and adherence to safety protocols are crucial for their efficient and safe operation.

 

Purpose of Steam Boiler

1. For generating power in steam engines or steam turbines.
2. In process industries for various processes.
3. For heating the buildings in cold weather and for producing hot water for hot water supply.

Types of boilers

In general, steam boilers are divided into the following 2 categories:

• Fire tube boiler
• water tube boiler

Of course, by using clean energies such as solar and nuclear energy in the relevant equipment (nuclear reactors), it is possible to produce superheated steam in large comparisons.

How a fire-tube boiler works in a tube

In this type of boiler, steam production takes place through the combustion of fuel in the furnace, and the fire or the combustion gases that pass through the second and third pass pipes transfer their heat to the water through the body of the pipes and the furnace. They turn it into steam. These steam boilers are used in food and sugar industries, hospitals, rubber industries, etc., and the working pressure of super heat steam required in such industries is usually from 10 bar to 25 bar maximum.

How the water-tube boiler works in the tube

In the water tube boiler, the water flows in the connecting pipes between the upper drum and the lower drum and by receiving thermal energy from fuel combustion through radiation in the furnace and moving it to other parts, it turns into steam. These boilers (water-tube) are used in industries such as refineries and power plants when capacities higher than 100 to 1000 tons of steam per hour and higher work pressures of 30 bar (up to 200 bar) are needed.

How Steam Boilers Are Made

A steam boiler heats water much like a teapot, only on a larger and more complex scale. Though not every steam boiler is the same, there are basic elements that are common to all steam boilers: burner, combustion chamber, heat exchanger, expansion tank, steam temperature control, safety relief valve, and low water cutoff.

The designs and types of steam boilers widely vary depending on their construction and purpose.

List of Made Steam Boilers

Burner

The purpose of the burner is to inject fuel and air into the combustion area. The fuels, such as oil, gas, or pulverized coal, have to mix easily with air. Dampers are used to regulate the amount of air that enters the burner. An impeller circulates the air evenly around the burner. Pipes referred to as spuds inject the fuel into the boiler and are ignited by an igniter.

 

 

Combustion Chamber

The combustion chamber contains the reaction of the fuel with air and uses it to create the heat to produce steam. To enhance the efficiency of the combustion chamber, it needs to be adequately insulated to avoid loss of heat through radiation. The combustion chamber has tubes containing water and steam that pass through the open box with the burner and controls. Efficient combustion is an essential part of boiler operations. The heat produced in the combustion chamber is absorbed on the surface of the boiler at the top of the combustion chamber.

Heat Exchanger

The heat exchanger allows heat to be exchanged between fluids without allowing the substances to mix. A heat exchanger contains a long coiled pipe that is immersed in the fluid to be heated. Gas or a heated liquid passes through the pipe and heats the water around it. Heat exchangers are made of a variety of materials with stainless steel being the best material since it does not corrode or rust.

 

 

 

Expansion Tank

The expansion tank helps to maintain the pressure in a boiler by providing a place for water to expand, absorb the pressure, and regulate the pressure. The tank has a diaphragm that is divided into two sections with one portion accepting water from the boiler and the other side being controlled by an air valve to alleviate pressure. The air valve pushes against the water in the other section until normal pressure is reached.

Steam Temperature Control

Steam temperature control prevents thermal stress; precise control of steam temperature is important. The control of pressure and temperature is necessary to keep fuel costs down. Steam temperature is normally controlled by spraying water on the first and second stage superheater. This is done using an attemperator or desuperheater.

Other methods to control steam temperature are through the use of flue gas circulation, flue gas bypass, or the tilting angle at which the burners fire the furnace. The simplest method for controlling steam temperature is to monitor the temperature of the steam as it exits the boiler and change the position of the spray water valve.

Safety Relief Valve

The pressure relief valve is the most important safety measure for steam boiler use. It ensures that the build up of pressure in a steam boiler will be relieved; this assists in avoiding a catastrophic disaster. The pressure relief valve opens when the pressure reaches a critical level and closes when the pressure returns to normal.

 

Low Water Cutoff

A low water cutoff turns off the burner or shuts off fuel to a steam boiler when the water level drops below a set point. A dry fired boiler can rupture or suffer significant failure. Low water cutoffs are another safety feature built into a steam boiler to help avoid damage and harm to the boiler. They are a normal part of boiler construction and are installed in steam boilers and hydronic devices to shut down the boiler in the case of the loss of water.

 

 

 

Uses for Steam Boilers

The traditional function of steam boilers is to serve as central heating for homes, offices, businesses, hospitals, and other facilities. Regardless of where they are used, all boilers have the same basic functions and mechanisms that work as a contained heat generating combustion process.

There are a variety of fuels used to generate the heat in a boiler to ignite the burner. The created heat moves through the system using pumps and heat exchangers .In order to specialize the function of a steam boiler, additional control mechanisms are added.

Steam Boilers Uses

1. Aquariums
2. Food and Beverage
3. Laboratories
4. Skyscrapers
5. Brewing
6. Power Generation
7. Lumber Kilns

Conclusion

• A steam boiler is a steam producing heating system; it produces energy by heating water to create steam.
• A steam boiler burns fuel to heat water. The combination of heat and water produces steam.
• Steam boilers are defined by their construction, portability, types of tubes, types of fuel, and the pressure they produce.
• A steam boiler absorbs heat that is released from combustion. The three ways that the heat is transferred are radiation, convection, and conduction.
• The designs and types of steam boilers widely vary depending on their construction and purpose.