A novel method of combined desulfurization and heat utilization of low-temperature flue gas from hot blast stove for blast furnace: Laboratory research and industrial application

Abstract

To address the challenges of low waste heat utilization rates and high desulfurization costs, this study proposes a novel method for combined desulfurization and heat utilization of low-temperature flue gas. By utilizing the low-temperature flue gas from hot blast stoves to dry lump metallurgical coke, the method also achieves flue gas desulfurization during the lump coke drying process. During the drying process, the wet lump coke desulfurizes due to the reaction between water vapor in the lump coke and the SO2 and oxygen in the flue gas, resulting in the formation of sulfuric acid. Additionally, the coke powder generated by friction during the drying process of lump coke has a large specific surface area, enabling it to adsorb additional quantities of SO2 and enhance the desulfurization process. It's important to note that the lump coke itself does not exhibit adsorption properties towards SO2 during the drying process, and the gas is not retained within the lump coke. Industrial applications indicate the outlet flue gas temperature is reduced from 175 °C to 60 °C, and the concentration of SO2 in the outlet flue gas is reduced from 150 mg/m3 to 29 mg/m3.