Supercritical water oxidation devices design, product and performance analysis

The problem of environmental pollution has become one of the most important problems to be solved at national and international political level with the increasing environmental awareness in recent years. Pollution of surface and groundwater is one of the most important environmental problems. In the treatment of wastewater, mechanical, biological, physical and chemical treatment methods are used separately or together. However, these methods have difficulties in removing persistent and toxic organic materials. In methods such as chemical coagulation / flocculation, chemical precipitation, permanent toxic organic material removal efficiency is low. Distillation and adsorption units are very expensive methods, although high yields are obtained in permanent and toxic organic matter removal. Chemical Oxygen Demand (COD) removal is high in membrane systems, but concentrated water methods are required in these technologies. Therefore, there is a need for advanced oxidation technologies in the treatment of industrial wastewater containing persistent and toxic organic matter. Considering all these, Supercritical Water Oxidation Method (SCWO) stands out among the systems used. With the SCWO method, the wastewater treatment system achieves over 90% success in removing permanent and toxic substances. In addition, long-term studies with other methods can be done in a very short time thanks to this system. Supercritical water is a fluid heated above the critical temperature (374.8 oC) and compressed beyond critical pressure (221.3 Bar). It shows the mixture of liquid and gas phase. Their densities are close to the liquid and their diffusibility and viscosity are close to those of the gas phase. Their high diffusivity allows them to easily penetrate into solids and close to liquid densities to dissolve solid matrices. In this way, high purity water purification can be done. In this thesis, a device which can be adjusted to different working conditions (220-300 Bar pressure, 375-500 oC temperature) and which can treat different wastewater (dirty water, waste water, etc.) is designed and produced. In addition, the performance analysis of the critical reactor section in the use of 304 (X5CrNi18-10) and 316 (X5CrNiMo17-12-2) grade stainless steel material was performed.