Corrosion of high temperature alloys in supercritical water oxidation systems
- Forschungszentrum Karlsruhe (Germany)
Supercritical water oxidation (SCWO) is a promising and very effective method for the oxidation of organic wastes. Its high solubility for organic compounds and its special physical properties (i.e. density, viscosity) resulting in a key advantage over standard processes like incineration. Due to the formation of HCl during oxidation of chlorine organics, a severe corrosion attack of most of the materials has been observed. This paper describes the results of investigations of high temperature alloys like alloy No. 214, alloy 602 CA, G-30 alloy, alloy 625, and alloy 686, exposed at 400 bar and 420 C for 24 hours in a CH{sub 2}Cl{sub 2}/H{sub 2}O{sub 2} mixture with about 2,000 wppm of chloride. The weight losses of all, samples varied between 3 mg/cm{sup 2} for G-30 alloy and about 73 mg/cm{sup 2} for alloy 686. The alloy No. 214 showed an increased corrosion for the preoxidized material, whereas the corrosion rate of alloy 602 CA was reduced by a factor of 3 due to the preoxidation at 900 C, prior to SCWO-exposure. The post mortem analysis revealed that alloy 686 has lost most of its nickel down to a depth of about 150 pm. The G-30 alloy showed a good corrosion behavior because of the formation of a protective oxide layer during the exposure. The layer was homogeneous with a thickness of about 12 pm, but a slight nickel leaching was observed, too.
- OSTI ID:
- 350168
- Report Number(s):
- CONF-980316-; TRN: IM9925%%516
- Resource Relation:
- Conference: Corrosion `98, San Diego, CA (United States), 22-27 Mar 1998; Other Information: PBD: 1998; Related Information: Is Part Of Corrosion `98: 53. annual conference and exposition, proceedings; PB: [6600] p.
- Country of Publication:
- United States
- Language:
- English
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