Reduction of SO2 to elemental sulfur with carbon materials through electrical and microwave heating methods

To develop a new process for reducing SO2 to elemental sulfur, the reduction of SO2 with carbon materials heated by electrical and microwave were investigated on a fixed bed experimental system. The effects of carbon species, temperature, SO2 concentration and C/SO2 molar ratio on SO(2 )reduction were studied. The results showed that coconut shell activated carbon has the best reduction effect among the six carbon materials. With the increase of reaction temperature, the X-SO2 gradually increased. However, the Y-S rapidly decreased at 800 degrees C and reached a minimum value of only 55 % at 900 degrees C. The X-SO2 increased with the increase of C/S mole ratio, but the Y-S showed a different trend according to the different reaction temperature. By comparing the effects of microwave heating and electrical heating on the reduction of SO2, the much lower temperature was required to obtain the same X-SO2 under microwave heating than that under electrical heating. Also for the S-S, the results obtained under microwave heating were higher than that of electrical heating. When the reaction temperature was 950 degrees C, X-SO2 was about 98 % under both heating modes. However, Y-S under microwave heating was 95 %, while Y-S under electrical heating was only 85 %.