Filtration failure occurs when filter media are blocked by accumulated solid particles. Suitable operating conditions were investigated for cake cleaning by partial oxidation of filter-cake particles (FCPs) during biomass gasification. The mechanism of the FCP partial oxidation was investigated in a ceramic filter and by using thermogravimetric analysis through a temperature-programmed route in a 2 vol % O-2-N-2 environment. Partial oxidation of the FCPs in the simulated product gas environment was examined at 300-600 degrees C in a ceramic filter that was set and heated in a laboratory-scale fixed reactor. Four reaction stages, namely, drying, preoxidation, complex oxidation, and nonoxidation, occurred in the FCP partial oxidation when the temperature increased from 30 to 800 degrees C in a 2 vol % O-2-N-2 environment. Partial oxidation was more effective for FCP mass loss from 275 to 725 degrees C. Experimental results obtained in a ceramic filter indicated that the best operating temperature and FCP loading occurred at 400 degrees C and 1.59 g/cm(2), respectively. The FCPs were characterized before and after partial oxidation by Fourier-transform infrared spectroscopy, scanning electron microscopy, and Brunaeur Emmett Teller analysis. Fourier transform infrared spectroscopy analysis revealed that partial oxidation of the FCPs can result in a significant decrease in C Fin (alkyl and aromatic) groups and an increase in C=O (carboxylic acids) groups. The scanning electron microscopy and Brunaeur Emmett Teller analyses suggest that, during partial oxidation, the FCPs underwent pore or pit formation, expansion, amalgamation, and destruction.