Kinetic Studies on Karlıova Coal

Abstract

In this study, reaction kinetics of the liquefaction of Karlıova coal in a process development unit having three reactors in series have been studied at temperatures of 530–570°C and pressures of 15–25 MPa. It is shown that the rate of hydrogen consumption can be expressed as a function of the concentrations of coal and catalyst, hydrogen partial pressure, reaction temperature, and residence time, and is controlled by the rates of hydrogenation of polynuclear aromatic components and the rates of formation and stabilization of radicals. The relative contribution of these reactions, at any temperature, determines the influence of the hydrogen partial pressure on the rate of the hydrogen consumption. The kinetics of the decomposition reactions of coal to preasphaltene, asphaltene, and oil also have been studied. The apparent activation energies determined are 20 kJ/mol for coal to preasphaltene, 40 kJ/mol for preasphaltene, 66 kJ/mol for asphaltene to oil, and 174 kJ/mol for oil to gases.