Almost total desulfurization of high-sulfur petroleum coke by Na2CO3-promoted calcination combined with ultrasonic-assisted chemical oxidation

Publication date: December 2018Source: New Carbon Materials, Volume 33, Issue 6Author(s): Pu-jie Zhao, Cheng Ma, Ji-tong Wang, Wen-ming Qiao, Li-cheng LingAbstractA two-stage desulfurization method for high-sulfur petroleum coke was developed using Na2CO3-promoted calcination, followed by ultrasonic-assisted chemical oxidation. Using a Na2CO3 to coke mass ratio of 1:4 and an average particle size of 80 µm for the coke, the desulfurization efficiency of the coke reached a maximum of 67.2% using Na2CO3-promoted calcination at 900 °C for 2 h with a heating rate of 1°C /min. The total desulfurization after the subsequent ultrasonic-assisted oxidation with nitric acid (65 wt%) reached 93.5% at 80 °C for 12 h using a nitric acid/coke ratio of 20 mL/g. The amounts of sulfur removed by the Na2CO3-promoted calcination were 73.4% of the thiophenic sulfur and 59.8% of the sulfoxide, with the total amounts removed after the ultrasonic-assisted oxidation being 93.6 and 93.3% respectively. Na2CO3 reacts with H2S and shifts the chemical equilibrium to remove more sulfur during the calcination. Chemical oxidation converts dibenzothiophenic compounds to water-soluble ones. These jointly increase the desulfurization efficiency of the coke.

Source: New Carbon Materials - January 18, 2019 Category: Chemistry Source Type: research