Babcock and Wilcox Boiler_BME

BABCOCK AND WILCOX BOILER 

This boiler is exclusively used when pressure is above 25 bar and capacity requirement is in excess of 7000 kg of steam/hr. It is a water tube boiler. It is used to operate at high pressures.

Specifications : 
The particulars relating to one such boiler is given as under.
 Diameter of drum   : 2000 to 4000 mm 
Length    : 6000 to 9000 mm 
Size of the water tubes  : 76.2 to 101.6 mm 
Size of the upper header tubes : 38.4 to 57.1 mm
 Maximum working pressure : 42 bar
 Maximum steaming capacity : 40,000 kg/hr 
Efficiency    : 60 to 80 %

Characteristics of boilers 

1.It is horizontal.
2. It is stationary.
3. It is water tube.
4. Number of tubes are many.
5. It is externally fired.
6. It is has natural circulation for water.
7. It has a forced circulation for air and hot gases.
8. It uses both solid as well as liquid fuel.
9. It is high pressure boiler.

Working: 

• The water is fed into the boiler shell through the feed check valve. 
• Due to gravity water passes through the vertical tubes, header and fills up the inclined tube first. 
• The water then collects in the boiler shell. 
• The water level in the shell is adjusted with the help of the water level indicator. 
• The coal is put on trolley grate. The coal is fired. 
• The trolley is then pushed into fire space. In order to provide air for combustion of coal and circulation of hot gases, damper is lowered to the furnace level. The baffle plates do not allow hot gases to pass to the right side. 
• These gases heat the super heater and moves down. These gases travel in the sine wave from and then move to the smoke box fitted with the long chimney. 
• Water in the upper portion of the tubes is heated and rises up. The cold water from the down take header rises to take its place and water from the boiler drum flows down.
• Till the temperature of water in the tube and in the drum becomes uniform, the circulation of water continues. 
• Finally the water in the upper portion of the tubes is converted into steam. 
• It is then collected in the boiler shell. The steam collected above the surface of the water in the drum is wet steam. 
• The super heater is used to convert this wet steam into superheated steam. This superheated steam is then taken out through the steam stop valve fitted on the top of the boiler for different uses. 

You tube Link:
https://www.youtube.com/watch?v=ae_QmSRhD5w