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                           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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