Migration and transformation of SO2 and HCl in activated based multi-pollutant purification process
The adsorption and migration of SO2 and HCl are important factors for the efficient,safe,and stable operation of the purification unit in the multi-pollutant flue gas activated carbon purification process.The competi-tive adsorption of SO2 and HCl on the surface of activated carbon was studied by means of BET,XRD,FTIR,and XPS.The migration behavior of SO2 and HCl in different adsorption processes was also analyzed,and the material flow of SO2 in the whole process was calculated.The results show that the competitive adsorption of SO2 and HCl on activated carbon led to the enrichment of HCl in the countercurrent activated carbon process system,which may affect the stable operation of the desulfurization and denitrification unit.In the lateral stratified cross-flow activated carbon purification process,the activated carbon material layer was divided into front,middle and back chambers.The activated carbon in the front chamber mainly adsorbs SO2 and quickly moves out of the tower,taking away the absorbed heat,The medium chamber activated carbon is used for adsorption of low concentration SO2 and HCl.while the activated carbon in the back chamber mainly adsorbs HCl and directly exits the tower,and does not contact with the high-sulfur flue gas again,resulting in hydrogen chloride extrusion effect,eliminating the accumulation of SO2 adsorption heat and HCl enrichment.The mass concentrations(standard state)of SO2 and HCl detected at flue gas outlet in the practical project of lateral stratified cross-flow activated carbon purification are 4.4 and 2.4 mg/m3,respectively,and the efficiency of SO2 and HCl removal reaches 99.3%and 95.4%respectively,which realizes the efficient and stable operation of the system.At the same time,the material flow of SO2 and HCl is balanced in the whole process of"adsorption-desorption-acid making",and the resource utilization of sulfur and chlorine elements is realized through the subsequent acid making and acid wastewater salt extraction.
activated carbonSO2HClcompetitive adsorptionmigration and transformationflue gas
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