Method for oxidizing materials in supercritical water

A method for treating a material by hydrothermal oxidation comprising the following steps:

• a) introducing a fluid comprising water and an oxidizer under a pressure above 22.1 MPa into an annular zone and at one end of an essentially tubular reactor comprising an outer wall and an inner tube, the annular zone or the reactor being defined by the outer wall and the inner tube;
• b) heating the water/oxidizer fluid in said annular zone to a temperature above 374° C.;
• c) introducing the heated and pressurized water/oxidizer fluid obtained in step b) into the inner rube of the reactor at a second end of the reactor and simultaneously introducing the material to be treated into said inner tube at said second end of the reactor;
• d) mixing the heated and pressurized water/oxidizer fluid and the material to be treated into a first part of said inner tube in such a fashion as to oxidize the material to be treated, followed by cooling of the fluid/oxidized material mixture into a second part of the inner tube, and
• e) isobarically evacuating the cooled fluid/oxidized material mixture from the reactor directly from the inner tube to the one end of the reactor,
• the fluid and the material continuously or quasi-continuously running through the inner tube.