How is the excess air coefficient of a circulating fluidized bed boiler determined?
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How is the excess air coefficient of a circulating fluidized bed boiler determined?
The excess air coefficient has a significant impact on the combustion in circulating fluidized bed boilers; if an excessively low value is chosen for this coefficient, combustion becomes incomplete, resulting in increased losses due to mechanical incomplete combustion； On the contrary, if an excessively large excess air coefficient is chosen, it will increase the heat loss in the exhaust gases. Generally, an excess air coefficient of around 1.1 to 1.2 is appropriate for circulating fluidized bed boilers.
The excess air coefficient has a significant impact on the combustion in circulating fluidized bed boilers, as these boilers utilize direct coal combustion technology with gas-solid mixing inside the furnace. If the excess air coefficient is low, the solid carbon does not burn completely, resulting in increased losses； If the excess air coefficient is too high, it will increase the heat loss in the exhaust gases. Therefore, the excess air coefficient of this type of boiler is generally ~1.2. Moreover, this number is an economic value.
Is there a standard formula for calculation? ? ? ? I want it too :Q:Q:Q
The method for calculating the air excess factor can be found on Baidu; it is equal to 21/(21–oxygen content in the flue gas). It is reasonable to locate the oxygen content monitoring points in the flue duct before the preheater.