boiler, circulations, classifications, basic flow diagram

boiler

1. Steam generator
Let the fun begin…

2. Classification of boiler
Fire tube boiler
Water tube boiler
Lancashire boiler

3. Fire tube boiler
Cochran boiler

4. Babcock Wilcox boiler
Water tube boiler

5. Locomotive Boiler

6. Water tube boiler Fire tube boiler
Operating pressure high (upto162 bar) Low (<24 bar)
Heating surface high less
Rate of steam
production
High low
Steam temperature High (upto 560
0
C) Low (Upto 340
0
C)
Water circulation good poor
Water treatment Necessary Not necessary
Chance of explosionHigh Less
Labour required Skilled Unskilled
Used for Large power plants Small plants
Overall efficiency 90% 75%

7. Classification of boiler
•Relative position of water and flue gas
•Direction of axis of boiler shell
•Furnace position
•Heat source
•Pressure of boiler
•Firing position
•Circulation

8. Pool Boiling

9. Classification of boiler
Fire tube boiler
Water tube boiler
Circulation

10. Boiler
Boiler
Boiler)(m drum from released steam saturated of rate flow mass
(m)downcomer in water saturated of rate flow mass
CR
g
   )TDF(x
1
mm/m
1
m
mm
CR
Top1ggg
1g




  
mDgHp  2
topbottom
m



 bottom D top
top
v
1
 fgtopftop
vxvv 
Advantage of forced circulation
CR=6-25, nat circulation

11. Once through boiler

12. Boiler mountings and accessories
Boiler mountings are
b) Safety valve
c) Fusible plug
a) water level indicator
e) Steam stop valve
f) Feed check valve
d) Pressure gauge
g) Blow off cock
Boiler accessories are
b) Superheater
c) Air pre heater
a) Economizer
e) Injector
d) Feed pump

13. Feed water flow path
HEATER
ECONOMISER
Condenser
WATER WALL
LP Turbine
BOILER DRUM SUPER HEATER
HP TurbineREHEATER
Pump