Oxygen corrosion of calcined cokes: I. Isothermal kinetics and texture variation

Abstract

Oxygen corrosion of the calcined cokes has been studied by kinetic and complementary methods. The shape of kinetic curves of S type facilitated treating the complex corrosion process as a superposition of two simpler reactions. The initial and final parts of a kinetic curve were simultaneously tested by a set of 16 simple kinetic equations. The best pair from 16 2 = 256 ones was chosen by the rival discrimination method and interpreted in terms of surface and bulk corrosions. The surface corrosion has been described as a consumption of small fragments of the carbon-layer packets idealized as sidewalk of cylinders. The packets screen the bulk of cokes against oxygen attack. The bulk corrosion has been described as a stochastic nucleation and growth of the channels penetrating the corroded coke. Evolution of pores in the course of corrosion, variation of the distribution of pores as well as scanning electron microscope images all agree with the oxygen corrosion models.