Experimental results using a transpiring-wall reactor (TWR) for supercritical water oxidation (SCWO) containing a hydrothermal flame as an internal heat source are presented. Our reactor set-up is aimed at overcoming the problem of reactor fouling and plugging due to precipitation of salts. Two types of transpiring-wall elements with different porosity were investigated. Experiments with artificial wastewater containing methanol and sodium sulfate in concentrations up to 6 and 3 wt.%, respectively, were used for a maximum operation time of 3 It. The salt deposition in the reactor was determined by electric conductivity and ionic chromatography measurements of the reactor effluent. About 65% of the salt introduced to the reactor was detected in the effluent. No plugging of the reactor and equipment was observed during the experiments and methanol conversion ratios higher than 99.99% were measured. (C) 2006 Elsevier B.V. All rights reserved.