Development of chemical looping desulfurization method for high sulfur petroleum coke

Abstract

High sulfur petroleum coke is an important by-product of petroleum industry, but it is hard to directly use due to the serious environmental pollution. The development of desulfurization technology has critical significance for the utilization of petroleum coke as resource, in which the thiophene represents the key difficulty in desulfurization. Here, by using a Fe2O3/Al2O3 composite as oxygen carrier, a chemical looping oxidation method was proposed to remove sulfur from petroleum coke for the first time. The Fe2O3/Al2O3 oxygen carrier could effectively oxidize the organic sulfur, and realized a removal efficiency of 63%. The used oxygen carrier exhibited a superparamagnetic property, and could be conveniently separated from the desulfurized petroleum coke. After air calcine, the oxidation ability of the oxygen carrier could be regenerated and used for another desulfurization cycle. Density functional theory calculations were conducted to elucidate the oxidation and evolution processes of thiophene by the oxygen carrier. The C-S bond in thiophene structure could be gradually destroyed by active oxygen, and transformed into sulfur dioxide after the desulfurization. The chemical looping oxidation provides a more convenient desulfurization method, which helps the resource utilization of high sulfur petroleum coke.