Enrique Nebot Sanz

Simulation of Supercritical Water Oxidation with Air at Pilot Plant Scale

Abstract Supercritical Water Oxidation (SCWO) processes have been studied by nu-merous researchers. The effectiveness of this approach to treat a wide variety ofwastes has been proved and the kinetics involved in some cases have been de-scribed. Phenol is commonly present in industrial wastewaters and it is extremelytoxic. Hence, phenol is a model pollutant that has been the subject of numer-ous studies by SCWO on a laboratory scale. In this work, a pilot-scale SCWOsystem has been used to compare experimental and predicted conversions in theSCWO of phenol, using the reaction kinetic equations obtained at the laboratoryscale. In this context, “PROSIM PLUS” software was employed to develop asimulator for the pilot plant facility, with the reaction kinetic parameters adjustedto represent the experimental data. In this study it was necessary to determinethe thermal losses between the experimental reactor and its surroundings. Thesethermal losses were obtained from tests with pure water and oxidant streams inthe absence of chemical reaction. An equation that predicted the effect of flowrate and temperature on the thermal losses was used. Experimental oxidation testswere conducted with initial temperature in the range 380 to 425Supercritical Water Oxidation (SCWO) processes have been studied by numerous researchers. The effectiveness of this approach to treat a wide variety of wastes has been proved and the kinetics involved in some cases have been described. Phenol is commonly present in industrial wastewaters and it is extremely toxic. Hence, phenol is a model pollutant that has been the subject of numerous studies by SCWO on a laboratory scale. In this work, a pilot-scale SCWO system has been used to compare experimental and predicted conversions in the SCWO of phenol, using the reaction kinetic equations obtained at the laboratory scale. In this context, “PROSIM PLUS” software was employed to develop a simulator for the pilot plant facility, with the reaction kinetic parameters adjusted to represent the experimental data. In this study it was necessary to determine the thermal losses between the experimental reactor and its surroundings. These thermal losses were obtained from tests with pure water and oxidant streams in the absence of chemical reaction. An equation that predicted the effect of flow rate and temperature on the thermal losses was used. Experimental oxidation tests were conducted with initial temperature in the range 380 to 425 C, at 250 bar and phenol concentrations ranging from 1 to 12 g/l. Good agreement in the simulation was obtained by adjusting the kinetic parameters within their confidence range. This simulator was used to optimize the SCWO of phenol solutions in the pilot plant facility.