MITIGATION OF FOULING AND AGGLOMERATION IN BIOMASS FUELLED BOILERS BY MEANS OF KAOLIN AND FIRED CLAY ADDITIVATION

The paper reports the results of an experimental research aimed at investigating the effect of kaolin and fired clay additivation on the properties of biomass ashes relevant to fouling and agglomeration occurrence, first of all the characteristic deformation temperatures. The behaviour of ashes derived from combustion of wood (chestnut), wheat straw and olive pomace has been characterized. The additivation with both kaolin and fired clay powder was effective to improve the high temperature ash behaviour of the biofuels rich in potassium, achieving a substantial increase of ash fusion temperature. Furthermore, the presence of kaolin in ash pellets inhibited formation of glassy phases, favouring the formation of friable structures.