4. Supercritical water gasification technologies

4.1 Materials and corrosion problems

The operating conditions of pressure and temperature required to reach the supercritical range of water severely restrict the use of common materials for pressure equipment construction. Indeed, the presence of acids, or their formation during the reaction from heteroatoms (Cl, S, F, P, B), leads to severe stress corrosion of the system [17]. Stress corrosion is the main corrosion phenomenon to be managed. It occurs without loss of mass under the effect of thermal and mechanical stress, and results in material cracking. To this must be added the phenomenon of corrosion under deposition, which occurs when materials rich in mineral salts are processed. The precipitation of these mineral salts alters the chemical potential of the medium at its interface...