OXIDATION OF PROPYLENE GLYCOL UNDER SUPERCRITICAL FLUID CONDITIONS

Despite its relative safety, propylene glycol requires effective disposal due to potential harm to health. Traditional disposal methods, including recovery, incineration, and regeneration, have high energy costs and can create additional environmental problems, such as the formation of toxic residues. Modern research is aimed at finding more efficient and cost-effective technologies. Promising alternatives to traditional methods are supercritical fluid (SCF) technologies, including supercritical water oxidation (SCWO). These methods provide deep oxidation of organic compounds under high temperature and pressure, which allows them to be converted into harmless products such as carbon dioxide and water. SCF technologies are characterized by high efficiency and low negative impact on the environment, which makes them attractive for industrial application, in particular, at PAO Nizhnekamskneftekhim for treatment of water discharge containing propylene glycol. The article presents the results of studies of supercritical aqueous oxidation of propylene glycol, which is used as a model fluid for testing the installation and the process methodology. Propylene glycol is also part of the organic composition of the water effluent of PJSC Nizhnekamskneftekhim, formed during the epoxidation of propylene with ethylbenzene hydroperoxide, which is used for the joint production of propylene oxide and styrene. The oxidation process was carried out at a temperature in the range of 653-748 K and a pressure of 25 MPa. The reaction time was about 30 minutes, and the oxygen excess coefficient varied from 2 to 4. The oxidation efficiency was estimated by the chemical oxygen demand.