Combustion and gasification properties of petroleum coke and its pyrolytic semi-coke

Abstract

In order to make full use of petroleum coke, isothermal pyrolysis experiments were conducted first, and then combustion characteristics at different oxygen concentrations and gasification properties of petroleum coke and its semi-coke were investigated. Results shown that when the pyrolysis temperature increased from 550 °C to 750 °C, the gas production increased from 31.6 mL/g to 192.8 mL/g. According to XRD results, the graphitization degree of semi-coke first decreased and then increased, and it was the lowest at 650 °C. Fitting results indicated that Avrami-Erofeev equation has the best linear correlation with combustion process. When the oxygen concentration increases from 21% to 80%, the combustion performance of PC, SC-550, and SC-750 increases gradually, and the SC-600, SC-650 and SC-700 reach the maximum at an oxygen concentration of 60%. Affected by the reduction of volatile matter and the change of graphitization degree, samples are divided into two types during the gasification process: the gasification rate changes obviously and relatively keeping stable. The gasification rate of semi-coke was higher than that of petroleum coke and negatively correlated with the degree of graphitization. Combustion with increased oxygen concentration and gasification with pre-pyrolysis are beneficial to the thermal conversion utilization of petroleum coke.