A two-step model for assessing the potential of shale-derived chemicals by oxidation of kukersite

Abstract

The organic matter in oil shale (kerogen) contains vast potential as its structure is rich in easily convertible and versatile building blocks. Due to the complex structure of kerogen, simplifications are often used in order to obtain any information about the mechanism of its processing. This paper presents an approximate two-stage kinetic model which has been constructed to describe the wet air oxidation (WAO) process of the kerogen of Estonian kukersite oil shale, i.e. an alternative oil shale treatment process. The results obtained highlight the basic mechanisms of oil shale oxidation by molecular oxygen in water into different products. These outcomes add to the already existing knowledge on the structure of kerogen and validate it. The composed two-stage reaction formula outlines a fast reaction period which describes the dissolution of organic material, followed by a slower oxidation of dissolved substances. The attained high dissolution rate of kukersite kerogen illustrates the potential for recovering feedstock chemicals. The rate constants found remained independent of the oxygen-to-carbon ratio and good agreement was observed between calculated kinetic curves and experimental values.