Corrosion behavior of Ni-base alloys and stainless steels insupercritical water containing potassium hydrogen carbonate

摘要

Most of the chemical applications of supercritical water (e.g. T > 550 ℃, p > 24 MPa)rnare associated with corrosion of the reactor materials. This is well known for thernoxidation of hazardous wastes (SCWO). For the process of gasification of organicrnmatter like pure methanol or other alcohols no corrosion has been observed. Alloyrn625 showed in aqueous solutions of potassium hydrogen carbonate negligiblerncorrosion rates at temperatures lower than 500 ℃. At higher temperatures (up to 700rn℃) fast general corrosion has been detected. In order to find reactor materials withrnbetter corrosion resistance several Ni-base alloys, stainless steels, as well as purernCr, and Fe were exposed under the same conditions. The alloys 602 and 33 showedrnthe best corrosion resistance under these experimental conditions.