Study on desulfurization and modification of high-sulfur petroleum coke via reduced iron powder catalytic roasting

Sulfur in petroleum coke poses significant environmental risks and damages equipment and carbon products, making its removal essential. This study presents a method for the desulfurization and modification of high-sulfur petroleum coke through catalytic roasting with reduced iron powder. The experimental results indicated that with a petroleum coke particle size of 75-58 mu m, an iron powder-to-petroleum coke mass ratio of 50 %, and roasting at 1400 degrees C for 1 h, the desulfurization rate reached 87.93 %, reducing the sulfur content to 0.91 wt%, with a product recovery rate of 80.82 %. A series of characterizations of petroleum coke products before and after desulfurization were conducted, revealing that both the desulfurization efficiency and the graphitization performance of petroleum coke were significantly enhanced by the addition of iron powder. Additionally, density functional theory calculations for the pyrolysis of benzothiophene showed that the energy barrier for the pyrolysis process was reduced in the presence of Fe catalysis, theoretically confirming the desulfurization mechanism. The resulting low-sulfur petroleum coke products can serve as raw materials for graphite preparation.