Hydrothermal Processing of Chlorinated Hydrocarbons in a Titanium Reactor

Abstract

Experiments are reported on the oxidative hydrothermal destruction of chlorinated organics in a cor rosion-resistant titanium reactor. Oxidation reaction conditions were 250−500 °C near 650 bar and reaction times of 30−100 s in a continuous-flow reactor. Trichloroacetic acid, trichloroethylene, and 1,1,1-trichloroethane behaved similarly. The organic concentration was ∼1.5 wt %; hydrogen peroxide was the oxidizer; sodium bicarbonate was added to achieve neutral pH. Hydrolysis occurs at low temper ature, producing chloride ion and secondary organics. Carbon dioxide is the sole carbon product at 500 °C. Sodium nitrate and sodium nitrite were also found to be effective oxidizers. Corrosion of the titanium was found to be slight (<0.038 mm/yr). The reaction mixture is likely not a single phase at these conditions. The destruction efficiency for trichloroethylene was estimated as 99.96% at 450 °C and 60 s, with <0.02% conversion to volatile chlorinated organic byproducts.