Characteristics of single petcoke particle during the gasification process at high temperatures

Particle concentration significantly affected the gasification of petcoke particles according to our previous studies.In this work,gasification characteristics and morphological evolution of single petcoke particle were investigated using a high temperature stage microscope experimental setup.The results showed that the reaction temperature significantly affected the reactivity of petcoke in the temperature range of 1200–1300°C.While the promoting effect on gasification reactivity decreased with further increasing the reaction temperature,the SEM analysis demonstrated the pore development during the gasification process,which attributed to the increase of reaction rate with conversion.The Raman analysis,HRTEM and SEM–EDX analysis showed that the heterogeneous graphitization of petcoke and non-uniform distribution of catalytic elements in petcoke attributed to the development of surface pores with limited depth.The gasification mechanism of petcoke particle can be briefly described as the reaction rate mainly contributed from the fast-reaction area.Besides,the pore development in fast-reaction area also enlarged the surface area of petcoke particle.

Wet Desulfurization of High-Sulfur Petroleum Coke Improved via Pre-calcination,H_(2)O_(2) Treatment,and Ultrasound

This work reports an improved method for the wet desulfurization of high-sulfur petroleum coke(petcoke)powder based on the combination of pre-calcination,H_(2)O_(2),and ultrasound.The results demonstrated that over 45%of the sulfur atoms were efficiently removed from Tianjin coke and Qilu coke(particle size<0.1 mm)by pre-calcination at 800℃ for 6 h followed by desulfurization with HNO3(8 mol/L)and H_(2)O_(2)(2 mol/L)solution at a reaction temperature of 60℃,a reaction time of 6 h,a liquid-to-solid ratio of 10 mL/g,and a 40 kHz ultrasonic power of 400 W.In addition,the specific surface area of the petcoke particles increased from 0.7 to 301.49 m^(2)/g.After desulfurization,the pore size distribution of the petcoke particles was more concentrated on micropores compared with the samples prior to petcoke treatment.Reactive force field molecular dynamics simulation results indicated that HNO_(3) continuously oxidized the carbon atoms adjacent to sulfur atoms in the petcoke macromolecules and promoted sulfur removal from petcoke via the cleavage of C-S bonds.The sulfur transformation mechanism can be summarized as follows:thiophene sulfur→branched chain carbon sulfur→CO_(2)S→C_(2)O_(2)S→C_(2)O_(3)NS→C_(2)O_(4)S→CO_(2)S.