Protection of internal surfaces in vessels against corrosive media attack

摘要

Method for protecting the internal surfaces in vessels against corrosive media attack, esp. in reactor vessels of high strength steel for reactions under super- or near-critical conditions, such as, for example, the combustion of polluted waste with substances, which are difficult to break down, in supercritical water, is disclosed. A non-corrosive fluid barrier medium contained at the same pressure as the corrosive medium by an intermediate wall separates the corrosive medium from the vessel wall. The intermediate wall between the corrosive and barrier media is of porous sinter through which a flushing flow is forced from the barrier medium side to emerge as a fluid film on the other side and run off.The reactor for carrying out the above method is also claimed. The reactor comprises a pressure vessel as the vessel as well as supply and take off pipes for the reactions partners. The reactor has the following novelties: (a) the vessel has a pressure pipe (1) as an outer sheath made of material highly resistant to the supercritical pressure in which a reaction pipe (4) is positioned and in which the supercritical reaction takes place; (b) the pressure pipe (1) is sealed at entrance (2) and exit (3) sides with covers (5,6), the supply and take-off pipes (11,16,19,23) of the process stream passing through the covers (5,6); (c) the annular space (17) between the reaction pipe (4) and the pressure pipe (1) is connected to a barrier media (18); (d) the reaction pipe (4) consists of two parts, it consisting of, seen from the processing direction, a front or upper porous sinter pipe (7) with porous walls and a rear or lower part (8) of the pipe connected to the other part and having a greater wall thickness; and (e) the lower part of the annular space (17) forms a dead volume (21) around the reaction pipe (4) in the area of the part of the pipe (8) having the greater wall thickness.