4-lump kinetic model for non-catalytic oil shale upgrading at sub- and supercritical water conditions

Abstract

The kinetics of non-catalytic oil shale conversion at sub- and supercritical water conditions was studied. All experiments were carried out in a batch reactor at 300–400 °C and 1–48 h. A four-lump reaction scheme is proposed, where oil shale produces synthetic oil, gas and coke, and some other reactions take place between products (coke to gas, synthetic oil to gas and synthetic oil to coke). Low average absolute error (<6.5%) was obtained, which corroborates the accuracy of estimated parameters of the developed kinetic model. The reaction rate was found to depend more on synthetic oil yield than on oil shale conversion according to the calculated reaction orders. The sensitivity analysis of the kinetic parameters showed that all values of the obtained reaction rate coefficients are the optimal. At temperatures near the critical point of water (350 and 400 °C), lowest values for asphaltenes and highest light fractions contents in synthetic oil were obtained.