Corrosion Phenomena of Alloys by Supercritical Water Oxidation of Halogenated Hydrocarbon in Batch Reactor and Anti-Corrosive Continuous Reactor

Sang-Ha Son1, Min-Jae Yoon1, Jae-Wook Lee2, and Chang-Ha Lee1. (1) Department of Chemical Engineering, Yonsei.university, 134, Sinchon-Dong, Seodaemun-Gu, Seoul, 120-749, South Korea, (2) Policy Division, Korea Institute of Geoscience and Mineral Resources, 30 Gajeong-Dong, Yuseong-Gu, Daejeon, 305-350

Supercritical water oxidation (SCWO) has been proved to be a powerful process to remove toxic and refractory wastes. Although SCWO is a very efficient technology for the treatment of hazardous wastes and wastewater, SCWO process has serious problem such as corrosion in the decomposition of halogenated hydrocarbon. Most of all, to remove such problems, it is important to understand corrosion phenomenon in SCWO conditions. In this study, surface chemical analysis was performed to understand corrosion of alloys by supercritical water oxidation in a batch reactor and a developed anti-corrosive continuous reactor. To test corrosion on alloys in SCWO condition, Stainless steel 316, Inconel 600, Hastelloy C-276, Monel 400, Titanium and Zirconium were selected. Since the phase transition from subcritical to supercritical condition and the corrosion of reactor could not be avoided in the batch reactor, it was hard to understand the effect of the applied condition on the corrosion phenomena. However, at the same condition, the level of corrosion for each alloys could be compared. On the other hand, the corrosion experiment was performed in the subcritical region and supercritical region, respectively, using the developed anti-corrosive continuous SCWO reactor. In the test of SUS-316 coupons, the microscopy images showed that the subcritical region and the supercritical region differently contributed to the corrosion phenomena. The experiments with other sample alloys such as Inconel 600, Hastelloy C-276, Monel 400, Titanium and Zirconium would be performed to investigate the different contribution to the corrosion phenomena. The corrosion results in the batch reactor and anti-corrosive continuous reactor will be compared.