Can
blowdown water heat be recovered ?
Yes, blowdown water
heat can be recovered in different ways. Spirax Blowdown
Heat Recovery Unit gives perfect solution to recover complete heat from
the Blowdown water and use it to heat Feed Water.
How does excess air affect the boiler performance
?
Excess air is the extra
air supplied to the burner beyond the air required for complete or stoichometric
combustion. If the supplied air is less, not only will this result in a
smoking stack, but it will significantly reduce the energy releases per
unit of fuel. Too little excess air is inefficient because it permits unburned
fuel, in the form of incombustible losses, to escape up the stack. But too
much excess air is also inefficient because it enters the burner at ambient
temperature and leaves back the stack hot, thus stealing useful heat from
the process. This excess air is a very crucial parameter for the operator
to monitor. The boiler efficiency analyzer EffiMax
2000 does this automatically by sensing the Oxygen in the stack, Steam
Generated, Steam Temperature and blowdown loss using an integrated circuit.
Here you can see
the recommended air excess for the different types of fuel:
|
Fuel
|
Type
of Furnace
|
%
CO2 Measured
|
%
Excess Air(rated)
|
|
Furnace
Oil
|
Multi
fuel burners & flat flame
|
3
- 4
|
16
- 22
|
|
Natural
Gas
|
Register
type burners
|
1
- 1.9
|
5
- 10
|
|
Natural
Gas
|
Multi
fuel burners
|
1.4
- 2.3
|
7
- 12
|
|
Coal
|
Stroker
fired, natural draft
|
7
- 8.3
|
50
- 65
|
|
Coal
|
Stroker
fired forced draft underfed
|
3.5
- 7
|
20
- 50
|
|
Crushed
Coal
|
Cyclone
furnace - suction / pressure
|
1.9
- 2.7
|
10
- 15
|
|
Pulverized
Coal
|
Partially
water cooled furnace for dry ash removal
|
2.7
- 6
|
15
- 40
|
|
Baggase
|
All
furnace
|
4.2
- 5.4
|
25
- 35
|
|
Wood
|
Dutch
oven & hoft type
|
3.5
- 4.2
|
20
- 25
|
|
Black
Liquor
|
Recovery
furnaces
|
1
- 1.4
|
5
- 7
|
Can
boiler be monitored on-line continuously ?
Yes, the EffiMax
2000 package explained above provides a complete monitoring and data
acquisition solution for your boiler performance. This sophisticated yet
simple to use analyzer operates on-line continuously, monitoring your boiler
efficiency every instant of its operation. EffiMax calculates the efficiency
of the boiler based on indirect efficiency computation and computes individually
the total amount of losses like stack loss, enthalpy loss, radiation loss
and blowdown loss in your boiler. Using the data generated on the system
losses, on-line suggestions can then be used to fine tune the system to
generate more steam with a lower quantity of fuel.
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