HIGH-TEMPERATURE PRESSURE VESSEL UNDER ACIDIC CONDITIONS AND METHOD FOR PREVENTING ITS CORROSION

摘要

PURPOSE:To prevent the inner surface of a pressure vessel from being corroded with acid by neutralizing the acidic gas and mist generated from a reaction vessel as a hydrothermal synthesis proceeds when the gas and mist are passed through an alkaline soln. CONSTITUTION:A reaction vessel 2 charged with various raw materials and corrosive acid is placed in a pressure vessel 1, and a hydrothermal synthesis is carried out. A cover part 3a is positioned above the vessel 2, and the inner cover vessel 3 is set so that an opening 3b is formed close to the bottom of the vessel 1. An alkaline soln. 5 is filled between the reaction vessel 2 and the pressure vessel 1 and freely circulated between the inside and outside of the inner cover vessel 3 through the opening 3b of the inner cover vessel 3. A lid 6 is airtightly fixed to the upper peripheral edge of the pressure vessel 1. As a result, the corrosion of the high-temp. pressure vessel 1 is prevented, and the reaction time for hydrothermal synthesis is reduced.