Kinetics of Crude Oil Coke Combustion

Abstract

ABSTRACT Coke is a solid or semi-liquid type material which deposits on the sand grain surface area and is eventually burned as a fuel during an in-situ combustion process. Its combustion is the main source of energy to sustain the firefront. This study investigates the effect of the different variables such as specific surface area, oxygen partial pressure and oil content on the coke combustion by thermogravimetric analysis (TGA). Each variable was varied while keeping the others constant. The TGA and the derivative thermogravimetric (DTG) curves were subjected to kinetic analysis. The rate equation produced indicated that the rate of combustion of the coke was proportional to the coke content yet to be burned, oxygen partial pressure, and specific surface area of the sand grain. The rate constant followed an Arrhenius-type equation for the temperature dependency. The rate equation was tested for the range of specific surface areas of 0.126 to 24.3 m2/g, oil content of 10 to 58 weight percent, and oxygen partial pressure of 0.05 to 0.50 atm. The validity of the model was tested for various crude oils from different geographical locations in the U.S.A., Canada and Latin America.