DETERMINATION OF KINETIC PARAMETERS FOR HYDROTHERMAL OXIDATION REACTION

The purpose of this study is to test a new and simple approach obtain reliable kinetic parameters over the hydrothermal oxidation of organic compounds. A tubular reactor system was used to carry out the oxidation of several model compounds: acetic acid, methanol and phenol. All experiments have been performed at isothermal conditions in the temperature ranges from 250 ºC to 500 ºC and at constant pressure of 25 MPa. At first, experimental procedure has been valided by determination of kinetic parameters of hydrothermal oxidation reaction assuming an zero order for oxygen concentration. So experiments have been performed with an oxygen excess of one order of magnitude regarding stoichiometric of the oxidation reaction. At second, oxygen order in the hydrothermal oxidation reaction have been determined. The intial oxygen concentration has been varied from 0.4 to 1.4 regarding the stoichiometric of the oxidation reaction. Two different methods, namely multiple linear regression and Runge-Kutta algorithm, have been tested to determine the kinetic parameters. Results obtained by both methods are similar, however Runge-Kutta algorithm is easier for kinetic parameters determination starting from experiments performed with laboratory scale or industrial scale pilot plant facilities.