Direct Injection of Oil Waste in a Supercritical Water Oxidation Reactor at Pilot Plant Scale

摘要

Several industrial wastes are difficult to treat by Supercritical Water Oxidation SCWO since they are not soluble in water at room temperature, leading to different procedure problems related to pumping and preheating in the aqueous feed stream. This work describes a new system suitable to treat non water-soluble wastes in a pilot plant that includes three independent feed streams: 1) an aqueous feed stream, 2) a feed stream containing the non water-soluble waste (i.e. oil waste) and 3) an air stream added before entering the tubular reactor. Once the oxidant and the organic compounds are mixed at high temperature, the oxidation reactions take place at a high rate, releasing an important amount of heat. With an adequate control of these feed streams, this technological solution would extend the versatility of the SCWO process in respect of the concentration of residues to be treated (normally limited to between 5 and 20% organic matter), since it allows the combined treatment of diluted residues (＜5%) in the aqueous feed and very concentrated residues (close to 100%) in the non-aqueous feed. The concentration desired in the reactor can thus be controlled, making it possible for the plant to remain self-sufficient in energy, or to generate surplus energy. This paper study the best procedure and operating conditions to mix those three streams (water-oil-air) leading to both safe and efficient performance of a process where oxidation reaction that take place at a high rate, releasing an important amount of heat.