Experimental research and commercial plant development for harmless disposal and energy utilization of petrochemical sludge by supercritical water oxidation

Petrochemical sludge is difficult to be degraded by traditional methods due to the complex organic pollutants, supercritical water oxidation (SCWO) is a promising technology for treating different industrial wastes. In this article, a comprehensive SCWO plant coupled with ammonia distillation and biochemical treatment with the processing capacity near 50 tons per day is designed. Experiments are conducted to determine the influence of reaction temperature, oxidation coefficient and residence time, meanwhile, the species of organics and the concentration of heavy metals in raw feedstock and products are also analyzed to determine the follow-up process. Furthermore, an indirect heat exchange unit between supercritical fluids, capillary device for pressure regulation, and gas–liquid–solid three-phase separator sealed by spiral are proposed to overcome the corrosion and plugging issues. Moreover, an economic evaluation including investment and running cost and the application prospect of the whole system are also analyzed in detail. These information will be significant for designing and constructing the commercial SCWO plant for other industrial wastes.