The material of graphite electrodes used in electric arc furnaces is needle coke. Despite much research on mesophase an‎d needle coke synthesis, there are still many ambiguities in this area. This study investigates the oil bitumens produced in Iran an‎d the oil obtained from the catalytic failure process in terms of composition an‎d structure, capability an‎d feasibility of synthesizing mesophase an‎d needle coke from them, an‎d the appropriate synthesis method. Therefore, this study investigated two samples of petroleum bitumen an‎d waste oil from the catalytic failure process in terms of composition, structure, aromatic compounds, an‎d the ability to synthesize mesophase an‎d needle coke. The mesophase bitumen synthesis process was performed at a high temperature an‎d pressure range. In order to synthesize mesophase bitumen from raw materials, a pressure reactor made of L303 stainless steel with the ability to work in the temperature range of 600 °C an‎d a pressure of 10 atmospheres was designed an‎d built. Thermal decomposition of petroleum bitumen an‎d oil catalytic failure process under high temperature an‎d pressure in the reactor was performed an‎d the effect of temperature, pressure an‎d addition of high aromatic oil parameters was investigated. In order to investigate the sulfur an‎d carbon content of bitumen an‎d oil samples, the catalytic failure process of Leco analysis was performed, which is an elemental analysis to accurately determine the concentrations of carbon, sulfur, hydrogen, an‎d nitrogen in solid organic an‎d inorganic samples. According to this analysis, the oil obtained from the catalytic failure process has the highest amount of carbon an‎d the lowest amount of sulfur compared to petroleum bitumen, which is one of the desirable properties for synthesizing mesophase an‎d needle coke. FTIR spectroscopy was used to eva‎luate the aromatization of raw materials. It was concluded that the waste oil of the catalytic fracturing process has more aromatization than other samples. In order to investigate the effect of temperature, mesophase synthesis was performed in the temperature range of 400 an‎d 500 °C. The effect of pressure was also investigated by performing the mesophase synthesis process at pressures of 2, 5 an‎d 10 atmospheres. It was found that the temperature range of 400 ° C an‎d the pressure of 10 atmospheres are suitable for the synthesis of needle coke due to the formation of mesophase an‎d larger an‎d more needle-shaped structure. Also, using the X-ray diffraction (XRD) pattern, the microstructure of samples was studied. These patterns showed that crystallinity an‎d structural order in the calcination of synthesized coke increased. The waste oil of the catalytic fracturing process had more structural order an‎d crystallinity than petroleum bitumen samples. The addition of high aromatic oil to bitumen positively affected the coke structure resulting from their composition. The morphology an‎d structure of the synthesized coke were examined using a polarized light microscope which confirmed the pattern of X-ray diffraction. A catalytic failure process is a good option for the synthesis of needle coke mesophase. The temperature range of 400 ° C an‎d the pressure of 10 atmospheres are ideal for synthesizing mesophase bitumen.

مسعود پنجه پور , مهدي احمديان

محمود مرآتيان اصفهاني , مريم كرباسي