Effect of intensification of the dendromass combustion process on corrosion of high-alumina refractory linings

• Main Authors: Vadász, Pavol, Plešingerová, Beatrice, Medveď, Dávid, Sučik, Gabriel, Bakajsová, Radka
• Format: Conference Proceeding
• Language: English
• Subjects: Aluminous refractories; Aluminum oxide; Ashes; Biomass burning; Castable refractories; Chemical composition; Combustion; Corrosion effects; Corrosion tests; Corundum; Criteria; Fusibility; Linings; Magnesite; Magnesium carbonate; Mechanical properties; Parameter modification; Phase composition; Refractory materials; Slag; Slagging; Thermomechanical properties; Viscosity; Wettability
• ISSN: 0094-243X; 1551-7616
• DOI: 10.1063/5.0164305

The study and evaluation of thermo-chemical, physico-chemical and thermo-mechanical properties of ashes is important for maintaining the smooth operation of boilers. Ash fusibility is a characteristic parameter of the fuel. The evaluative criteria predicting the behavior of ash are based on its chemical composition. The criteria used to characterize coal combustion are also used for the biomass combustion ash. Using these criteria the effect of the magnesite addition to dendromass ash was evaluated. The slagging, fouling and fusibility parameters of the original and modified ash with MgCO3 additive were compared. The ash fusibility index (fusibility temperature) increased significantly, and reactivity of the slag decreased with increasing MgO content in ash. Next, on the high-alumina refractory material, the corrosion test (static crucible corrosion test at 1450 °C/ 7 h) was carried with the dendromass ash with and without magnesite additive. The corrosion was visually evaluated from the degradation of (l-s) interface, and corrosion profile, and changes in the chemical and phase composition of the corrosion medium. The microstructure of the melt-refractory interface was studied by SEM/EDS. The slag preferentially attacks the binder phase of the corundum refractory castable, and a lesser extent the corundum grains. The change in the chemical composition due to the MgCO3 addition to ash manifested an increase of slag viscosity (slag viscosity index decreased), the wettability reduction of the corundum castable. The presented experiments are an introductory study aimed to reducing the corrosion of refractory materials by the modifying the composition of biomass and waste during their combustion.