The comparison of ash analysis results is shown in Table 6.
It confirmed the differences between coal and biomass/agromass
fuels. The coal ash sample was composed of the majority of silica
and alumina oxides, and contained just minor amounts of chlorine,
calcium, and alkali (sodium and potassium). Contrary to coal ash
the biomass and agromass ashes contained significantly higher
amounts of Na, K, and Ca compounds, as well as chlorine.
Furthermore, those ashes contained much less alumina oxide
compared with coal ash. Similar to the data presented in Tables 4
and 5 the values determined for the fuel described as ‘sunflower
pellet þ woodchips’ are not just a direct weighted average of the
corresponding data for ‘pure’ sunflower and ‘pure’ woodchips but
are affected by fuel origin, preparation, etc.