Hydrothermal processing of chlorinated hydrocarbons in a titanium reactor

Experiments are reported on the oxidative hydrothermal destruction of chlorinated organics in a corrosion-resistant titanium reactor. Oxidation reaction conditions were 250-500 degrees C near 650 bar and reaction times of 30-100 s in a continuous-Row reactor. Trichloroacetic acid; trichloroethylene, and 1,1,1-trichloroethane behaved similarly. The organic concentration was similar to 1.5 wt %; hydrogen peroxide was the oxidizer; sodium bicarbonate was added to achieve neutral pH. Hydrolysis occurs at low temperature, producing chloride ion and secondary organics. Carbon dioxide is the sole carbon product at 500 degrees 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 degrees C and 60 s, with <0.02% conversion to volatile chlorinated organic byproducts.