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Fuel handling

Screen graphics showing the current composition of the fuel composite at simultaneous combustion of coal, biomass (two types) and biogas

 

 

At present, in many power and CHP plants, co-combustion of two or more fuels is applied. Unless the proportion of fuels burned is forced, the question as regards the best ratio will always arise. In both cases these questions can be answered by efficiency assessment. To calculate efficiency, one needs to know the chemical composition of the fuel composite that is formed in the process of combustion of various fuels. Therefore the application systematically deter-mines the share of the elementary components that are fed to the boiler. The screen graphics show this as the composition of the fuel composite.
If two known fuels are burned, it is possible to perform regression analysis of the results of the afore-mentioned economic calculations and to obtain a simple dependency of the boiler efficiency on the fuel ratio.
The graph below shows such a dependency for a CFB boiler that is fired with coal and hydraulically fed coal slurry of inferior quality, but is much cheaper than the basic fuel.


Boiler efficiency at various shares of the additional fuel

 

 


Optimal share of the additional fuel in combustion
This graph - complemented with fuel prices - enables the optimum proportions of fuels to be determined. The graph presented above indicates explicitly how much additional fuel should be burned in order to ensure the highest possible revenues from energy sales in relation to the fuel costs.
Preparation of pulverised fuel to have it adapted for combustion in the boiler is a separate issue. Pulver-ised coal of adequate quality may be obtained by the monitoring of coal mills. This module is described in the section Monitoring of Coal Pulverizers.

 

 

download brochure "Fuel Handling" (0,3 MB)