Study On Desulfurization Of High Sulfur Petroleum Coke By Electrochemical Oxidation

With the increase in China’s petroleum imports,the sulfur content of processed crude oil increased,and the production of high-sulfur petroleum coke has also increased.When using high-sulfur petroleum coke,will cause problems such as a difficult desulfurization process,increased production costs,and serious equipment corrosion,at the same time,it will also cause great harm to the environment.Therefore,the presence of sulfur limits the application and development of petroleum coke.How to reduce the sulfur content of high-sulfur petroleum coke before use and improve its applicability is the focus and difficulty of high-sulfur petroleum coke research.In this study,a relatively mild,clean,simple operating condition and promising industrialized electrochemical oxidative desulfurization method were used to desulfurize high-sulfur petroleum coke.Drawing on and introducing new desulfurization oxidants and acid-base environment and other conditions to conduct desulfurization experiments,the desulfurization effect under different p H was investigated,the desulfurization yield was used as the selection criterion,and the oxidant and desulfurization environment suitable for electrochemical desulfurization were screened out.The electrochemical desulfurization conditions and process were optimized by single factor investigation and orthogonal experiment.The petroleum coke before and after desulfurization was tested by SEM,EDS,FTIR,XRD,XPS,BET,TG/DTG,and quality indicators,and its microscopic morphology,thermal stability flammability,a microcrystalline structure,chemical structure,specific surface area,pore structure and other properties,the electrochemical desulfurization mechanism of petroleum coke in this experimental system and the availability of petroleum coke after desulfurization treatment were discussed.Na Br was identified as an oxidant suitable for electrochemical desulfurization of high-sulfur petroleum coke by the desulfurization effect under wet chemical and electrochemical conditions.The electrochemical desulfurization of the acid-base system was investigated,and it was determined that CH₃COOH was the optimal acid system,and p H=3 was the optimal desulfurization condition.Through single factor screening and orthogonal experiments to optimize desulfurization conditions,the optimal desulfurization process conditions of Na Br-CH₃COOH（p H=3）electrochemical oxidation method are obtained:electrolysis current 25 A,number of plates 3（2 positive/1 negatives）,the distance between plates 8 cm,particle size 0.096-0.074 mm,Na Br concentration 13.75 g/m L,petroleum coke concentration 25 g/L,desulfurization time 480 min.To explore the mechanism of electrochemical desulfurization of petroleum coke,the gas,liquid phase,and solid products in the desulfurization process were tracked.According to the analysis results of characterization data,the sulfur in petroleum coke was finally converted into SO₃^2-and SO₄^2-in soluble forms,both organic sulfur and inorganic sulfur in petroleum coke were well removed,and the basic structure of petroleum coke did not change greatly after electrochemical desulfurization.After electrochemical desulfurization treatment,the combustion characteristics of petroleum coke become better,and it is suitable for combustion.