Boiler Presentation for Engineering and Education

Boiler

1. BOILER A PRESENTATION ON BY: Zainal MSc Roll. No- 13

2. * BOILER Boiler is an apparatus to produce steam. Thermal energy released by combustion of fuel issued to make steam at the desired temperature and pressure. The steam produced is used for: 1). For generating power in steam engines or steam turbines. 2). Heating the residential and industrial buildings. 3). Performing certain processes in the sugar mills, chemical and textile industries.

3. BOILER PROPERTIES a). Safety: The boiler should be safe under the operating conditions. b). Accessibility: The various part of boiler should be accessible for repair and maintenance. c). Capacity: Should be capable of supplying Steam according to the requirement. d). Efficiency: Should be able to absorb a maximum amount of heat produce due to burning of fuel in the furnace. e). It should be simple in construction. f). Its initial cost and maintenance cost is low. g). It should be capable of quick starting and loading.

4. CLASSIFICATION OF BOILERS The boiler may be classified as: Horizontal, Vertical or Inclined. Fire tube & Water tube. Externally fired & Internally fired. High pressure & Low pressure. Forced circulation & Natural circulation. Stationary & Portable. Single tube & Multi tube boilers.

5. 1. Horizontal, Vertical or Inclined If the axis of boiler is horizontal, the boiler is called horizontal boiler. If the axis is vertical then it is called vertical boiler. If the axis is inclined then it is called inclined boiler. Advantage of horizontal boiler: a. it should be repair easily. b. occupies less floor area.

6. 2. Fire tube & water tube boiler In the fire tube boiler the hot gases are inside the tubes & the water surrounds in the tube. ex. Cochran, Locomotive etc. In the water tube boiler the water is inside the tube & the hot gases are surround them. ex. Babcock & wilex , Lamont, Stirling boiler etc.

7. 3. Externally & Internally fired The boiler is known as externally fired if the fire is outside the shell. ex. Babcok & wilcox . In case of internally fired boilers, the furnace is located inside the boiler shell. ex. Cochran, Lancashire etc.

8. 4. Forced circulation & natural circulation In forced circullation type of boillers the circullation of water is done by forced pumps. ex. Velox , Lamont etc. In natural circullation type of boiller the circullation of water in boiler take place due to natural convention. ex. Lancashire, Babcock .

9. 5. High pressure & low pressure boilers The boiler which produce steam at pressure of 80 bar and above are called high pressure boiler. ex. Velox . The boiler which produce steam at pressure 80 bar are called low pressure boiler. ex. Cochran .

10. 6. Single-tube & multi-tube boilers The fire tube boilers are classified as single tube & multi tube boilers, depending upon the fire tube is one or more than one . Ex: Cornish boiler.

11. Boiler mainly classified as : Fire tube boiler . Water tube boiler .

12. a). FIRE TUBE BOILERS

13. b). WATER TUBE BOILERS

14. S no. Particulars Fire tube boilers Water tube boilers 1. Mode of firing Internally fired Externally fired 2. Rate of steam production Lower Higher 3. Construction Difficult Simple 4. Transportation Difficult Simple 5. Treatment of water Not so necessary More necessary 6. Operating pressure Limited to 16 bar Under high pressure as 100 bar 7. Floor area More floor area Less floor area 8. Shell diameter Large for same power Small same power 9. Explosion Less More 10. Risk of bursting Lesser More risk Comparison between Fire-tube & Water-tube boilers

15. TYPES OF FIRE TUBE BOILERS There are mainly five types of fire tube boilers.

16. 5). LOCOMOTIVE BOILERS

17. BOILER MOUNTING Boiler Mounting are the part of boiler and are required for proper functioning of boiler in accordance with Indian Boiler Regulation Act. Boiler mounting is essential fitting for safe working of boiler. These mounting are: 1). Fusible Plug If the water level in the boiler falls below a predetermined level, the boiler shell and tubes will be overheated.

18. 2). Water Level Indicator This indicates the water level in the boiler. 3). Pressure Gauge. This indicates the pressure of the steam in the boiler.

19. 4). Steam Stop Valve. It regulates the flow of steam supply outside. The steam from the boiler first enters into an ant-priming pipe where most of the water particles associated with steam are removed. 5). Safety Valve. The function of the safety valve is to prevent the increase of steam pressure in the holler above its design pressure.

20. 6). Feed Check Valve. The high pressure feed water is supplied to the boiler through this valve. This valve opens towards the boiler only and feeds the water to the boiler. 7). Blow-off Cock. The water supplied to the boiler always contains impurities like mud, sand and, salt Due to heating, these are deposited at the bottom of the boiler, they have to be removed using blow off cock .

21. Boiler performance 1) Evaporative capacity can be expressed in terms of: a) kg of steam/hr b) kg of hour/hr/m 2 of heating surface c) kg of steam/kg of fuel fired Boiler efficiency Ratio of heat actually utilized in the generator to the heat supplied by the fuel. Efficiency= m w (h- h f )/C Where C is the calorific value