The disclosed technology relates to methods of inhibiting corrosion in reaction chambers configured for hydrothermal reaction of feeds containing a heteroatom. An embodiment of such a method comprises providing a feed stream comprising a phosphorus-containing material, an alkali metal compound, water, and a corrosion-inhibitor. The embodiment additionally includes introducing the feed stream and oxidant into a reactor chamber and oxidizing the phosphorus-containing material at an oxidation temperature greater than about 374 C. and an oxidation pressure exceeding about 25 bar, wherein the reactor chamber has inner surfaces comprising a material that corrodes when in contact with a phosphorus compound within the reactor. The embodiment additionally includes selectively reacting the corrosion-inhibitor with phosphorus within the reactor, thereby precipitating in the reactor chamber a phosphorus-containing solid inorganic compound. The embodiment further includes forming in the reactor chamber an alkali salt melt and carrying away from the reactor chamber a mixture comprising the solid phosphorus-containing inorganic compound and the alkali salt melt.

The disclosed technology relates to methods of inhibiting corrosion in reaction chambers configured for hydrothermal reaction of feeds containing a heteroatom. An embodiment of such a method comprises providing a feed stream comprising a phosphorus-containing material, an alkali metal compound, water, and a corrosion-inhibitor. The embodiment additionally includes introducing the feed stream and oxidant into a reactor chamber and oxidizing the phosphorus-containing material at an oxidation temperature greater than about 374 C. and an oxidation pressure exceeding about 25 bar, wherein the reactor chamber has inner surfaces comprising a material that corrodes when in contact with a phosphorus compound within the reactor. The embodiment additionally includes selectively reacting the corrosion-inhibitor with phosphorus within the reactor, thereby precipitating in the reactor chamber a phosphorus-containing solid inorganic compound. The embodiment further includes forming in the reactor chamber an alkali salt melt and carrying away from the reactor chamber a mixture comprising the solid phosphorus-containing inorganic compound and the alkali salt melt.

The present disclosure relates to a method for removing chlorine from waste plastic pyrolysis oil, the method including: (S1) mixing and reacting waste plastic pyrolysis oil with a neutralizing solution that contains a neutralizer containing M-OR.sub.1 and a solvent; and (S2) subjecting a fluid generated in the step (S1) to a water treatment to remove chlorine, wherein M is an alkali metal or an alkaline earth metal, and R.sub.1 is a C.sub.1 to C.sub.10 alkyl group.