The action of heavy oil combustion products on aluminosilicate refractories

Aluminosilicate refractory bricks exposed for a long period to the action of heavy oil combustion products were analysed. The bricks located in zones characterized by higher working temperatures are mainly degraded by Na 2O and V 2O 5, while SO 3 represents the most important contaminant at lower working temperatures. Two series of different mixtures were prepared, taking into account the significant increase in the contaminant contents of the refractory bricks exposed to fuel oil products. V 2O 5, Na 2O and SO 3 were added to as-received aluminosilicate refractory and to a mullite-cristobalite mixture. These mixtures, in pelletized form, were thermally treated at temperatures ranging between 600 and 1300°C. The results enable the differences between the data obtained in laboratory and those observed in refractory bricks employed in combustion chambers to be explained. In this last case, in fact, preferential contact between impurities and refractory material may be expected in microzones of the brick characterized by the presence of cracks and pores in which the fuel oil impurities might concentrate. © 1987.