Quantification of Deposit Formation Rates as Functions of Operating Conditions and Fraction of Biomass Fuel Used in a Converted PC Boiler (100 MW)
Statistically designed experiments were carried out to study the potential effects of operating parameters on the extent of slagging, fouling and sulphur retention in a 100 MW PC boiler burning a combination of wood powder and oil. The influence of primary air, burner air distribution (secondary/tertiary air), secondary air (upper and lower burners), over fire air (east, west and rear), flue gas recirculation, fuel distribution. load and fraction of biomass fuel used were evaluated using first a screening design and then a face-centred composite design (CCF). Polynomial models were deducted from statistical analysis of the experiments. The general results from the study are that wood powder in combination with oil can be used in a safe way with relatively small amounts of deposits formed. The dominating influential factor was the fraction of biomass fuel used, where an increase resulted in somewhat higher sulphur retention but a slightly greater fouling. However. chemical analysis of samples collected during the tests did not indicate any severe corrosion tendencies and the fuel combination has been successfully used for more than two years now, without any ash related operational problems.
KeywordsBiomass Fuel Wood Powder Statistical Experimental Design Nitrogen Oxide Emission Sulphur Retention
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