Features of liquid phase oxidation of tar in the presence of modifiers-catalysts

Abstract

Modifiers that provide catalytic effect in the tar oxidation were cons idered. The use of iron stearate, cobalt salts as modifiers was studied. The modifier concentration in the tar amounted to 5.0% by weight. The tar modification effect on the oxidation kinetics was defined. The relationships between oxidation rate constants and oxidation time were analyzed for the modifiers-catalysts. It was demonstrated that modifiers which contained salts of metals with variable valence had the catalytic or inhibitory effect on the oxidation, depending on the modifier concentration in the tar. It was shown that the addition of modifiers-catalysts effects on the quality characteristics of the oxidized bitumen. The relationships between softening point and penetration were determined for oxidized bitumen from the modified or unmodified tar. The article presents a comparison of oxidized bitumen derived from modified tar by modifiers-catalysts in the optimal concentration. modifier nature was the main factor determining the effectiveness of modifiers, which affected the structure of the oil system. Inhibitory and catalytic effects on the oxidation were executed by the addition of brown coal pyrolysis resins and oil shale py rolysis resins, respectively. Analysis of the kinetic curves allowed establishing the following: iron stearate had the greatest effect on the oxidation process, the effect allowed to increase rate constant to 8.7 times. It has been established that the addition of cobalt modifier can improve the thermal-oxidative stability of the oxidized bitumen.