Study on sulfur migration and carbon consumption during regeneration of SO2-loaded activated carbon: Effect of alkali/alkaline earth metals

Abstract

Activated carbon (AC) has emerged as a new technology with promising application prospects for environment friendly SO2 removal, and the thermal regeneration process of SO2-loaded AC is the key step to realize adsorbent circulation and sulfur recovery. Herein, the synergistic effects of alkali/alkaline earth metals in ash on sulfur migration and carbon consumption were studied based on fixed bed adsorption and thermal regeneration. The experimental results showed that the adsorption atmosphere has a significant effect on gas desorption. In the temperature range of 150–850 °C, SO2 was the cause of excessive CO2 release during regeneration compared with non-adsorbed AC. Among them, the carbon consumption caused by CO2 release in the relatively low temperature range (150–500 °C) was mainly due to the regeneration reaction of chemisorbed SO2. The carbon consumption in the relatively high temperature range (500–850 °C) was mainly related to the Ca-based sulfate formed in the adsorption process, which was reduced during heating to release CO2. This study elucidates the synergistic effect of ash on the sulfur migration and carbon consumption in the process of regeneration, which provides a deeper understanding of the AC flue gas desulfurization and regeneration process.