Steam boilers can be classified in several ways, including by how water and gases flow (fire tube or water tube), how they are fired (internally or externally), how water circulates (natural or forced circulation), operating pressure (low or high), intended use (stationary or mobile), and position (horizontal, vertical, or inclined). Common boiler types include fire tube boilers like the Scotch marine boiler, water tube boilers like the Benson boiler, and boiler accessories that improve efficiency like economizers and superheaters. Steam from boilers can power turbines, which are either impulse turbines like the De Laval or reaction turbines such as the Parsons.

1. Uses of steam boilers
 Power Generation plants
 Process industries like sugar, paper and chemical industries
 Textile industries
BOILERS

2. Classification of Boilers
According to flow of water &hot gases
a. Fire tube boilers
b. Water tube boilers
According to the method of firing
a. Internally fired boilers
b. Externally fired boilers
According to method of water circulations
a. Natural circulation boilers
b. Forced circulation boilers

3. According to pressure developed
a. Low pressure boilers
b. High pressure boilers
According to nature of service to be performed
a. Stationary boilers
b. Mobile boilers
According to position of the boiler
a. Horizontal boilers
b. Vertical boilers
c. Inclined boilers

4. According to number of Drums
a. Single drum boilers
b. Multi drum boilers
According to nature of Draught
a. Natural Draught boiler
b. Forced Draught boiler

5. Comparision between fire tube and water
tube boiler

6. Simple Vertical boiler

7. Cochran boiler

8. Lancashire Boiler

10. Babcock and Wilcox Boiler

11. Stirling boiler

12. La-mont boiler

13. Benson boiler

19. Boiler Accessories
Feed Pump
Economizer
Air Preheater
Super heater

20. Steam turbine
 Classification of Steam Turbine
a. Impulse turbine
b. Reaction turbine

21. De-laval turbine

22. Parsons Reaction turbine