The highest values of this ratio were recorded during the combustion of oil cake pellets at the maximum flow rate
of air supplied to the boiler. Lower values were observed at the air flow of 1 m/s. Accordingly, average values for
this fuel amounted to 613 and 469 mg•m-3 at 10% O2. Much lower values were reported during combustion of other
types of pellets. At the air flow rate equal to 1 m•s-1, the mean SO2 emission values were about 100 mg•m-3 at 10%
O2, while at average rate of 2.5 m•s-1 about 10 mg•m-3 at 10% O2 (Table 4).