Performance on desulfurization and denitrification of one-step produced activated carbon for purification of sintering flue gas

Abstract

An innovative one-step process for activated carbon production from low-rank coal is proposed in this research by applying oxidized pellets as activator. The new process can realize synchronous production of the activated carbon and direct reduction iron through combination of carbonization and activation of low-rank coal in one step while no solid wastes were discharged. The desulfurization and denitrification performance of the obtained activated carbon was also evaluated on the simulative sintering flue gas in comparison with one type of commercial activated carbon. The results indicated that a superior activated carbon with high specific surface area of 370.42 m2 g−1, iodine sorption value of 695.13 mg g−1, compressive strength of 315 N·per−1and abrasive resistance of 96.61%, can be prepared under suitable conditions of activation temperature at 850 °C for 140 min with C/Fe mass ratio of 2.5. Meanwhile, the direct reduction iron has a metallization ratio of 88.31%. The activated carbon has a preferable desulfurization performance with the breakthrough sulfur capacity of 5.463 mg/g and breakthrough time of 46.33 min, and single denitrification performance with the breakthrough nitric capacity of 1.935 mg/g and breakthrough time of 90.17 min at flue gas temperature of 80 °C, airspeed ratio of 8370 h−1, gas flow of 1.8 m3/h, and oxygen concentration of 16%. The denitrification of activated carbon in the simultaneous desulfurization and denitrification process can be improved by catalytic reduction via the transformation from NO to N2. The good results show that this process has a bright future with high technical and economic feasibility.