Corrosion inhibition in hydrothermal processing

A method of oxidizing a feed material, comprising:

• providing a feed stream comprising water, a corrosion inhibitor, a waste feed comprising a phosphorus compound and melt-forming agents that form an alkali metal salt melt at a temperature greater than about 374° C. and a pressure exceeding about 25 bar;
• introducing the feed stream and an oxidant into a reactor chamber and oxidizing the feed stream at the temperature and pressure, wherein the reactor chamber has an inner surface comprising a material which is susceptible to corrosion when in contact with a phosphorus-containing corrosive agent formed from the phosphorus compound in the reactor chamber;
• selectively reacting the corrosion inhibitor with the phosphorus-containing corrosive agent, thereby precipitating in the reactor chamber a solid phosphorus-containing inorganic compound;
• forming in the reactor chamber an alkali salt melt;
• and
• flowing away from the reactor chamber a mixture comprising the solid phosphorus-containing inorganic compound and the alkali salt melt.

A method of inhibiting corrosion in a supercritical water oxidation (SCWO) system during oxidation of an organic waste material at a SCWO operating condition, comprising:

• providing a SCWO reactor having a titanium inner surface;
• introducing to the SCWO reactor a feed stream comprising the organic waste material, the organic waste material comprising an organophosphorus compound;
• introducing to the SCWO reactor an alkaline earth compound that selectively reacts with phosphorus of the organophosphorus compound to form an insoluble phosphorus-containing compound under SCWO conditions, the alkaline earth compound comprising at least one of magnesium and calcium;
• introducing to the hydrothermal reactor sodium-containing salt constituents in an amount effective to form a salt melt at the hydrothermal operation condition, the salt melt comprising the insoluble phosphorus-containing compound;
• operating the SCWO reactor at the SCWO operating condition for a residence time effective to treat the organic waste material and thereby release phosphorus;
• and
• removing at least a portion of the salt melt from the SCWO reactor.