Study On DeNOx And Dechlorobenzene Performance Over Actived Carbon Material

Due to the micropore and strong adsorption ability,active carbon catalyst is wildely used in the control of complex pollutants from flue gas,such as NO_x,SO₂,dioxin（PCDD/F）,ash,and heavy metal.This study aimed to investigate the NH₃-SCR performance of active carbon catalyst.Then,physical and chemical characterization methods were used to analyze the physical structures and NH₃-SCR performance of active carbon dopping with V and Fe.Chlorobenzenes was used as the model of PCDD/F.We studied the variety of the saturated adsorption capacity of clorobenzene in difference operational condition and tried to fit the breakthough curve by different Kinetic equation.Finally,active carbon which adsorbs with chlorobenzene was treated safely using low temperature thermal dechlorination method.The main conclusions of this thesis are as follows:The NH₃-SCR activity of active carbon dopping with V increased with the increase of V content.When V up to 5%,the NH₃-SCR performance was the best.At 200℃,NO_x conversion can reach about 100%.In the aspect of sulfur resistance,when the loading of vanadium is low,SO₂ can obviously promote the NO_x conversion.However,when the vanadium dopping exceeded 3%,SO₂ not only failied to promote the removal of NO_x but also inhibited the conversion of NO_x.Indicating the vanadium loading is too high bad for the resistance to sulfur of active carbon.The NH₃-SCR performances of carbon catalyst before and after pre-sulfur treatment were compared.Pre-sulfur treatment increased the surface acid sites of active carbon and the NH₃-SCR performance of active carbon.Loading both V and Fe on active carbon,the V/Fe ration of 0.5/3 had the highest NH₃-SCR performance below 250℃.When the proportion of iron increased,the active component agglomeration decreased the activity.We studied the saturated adsorption capacity of clorobenzene in difference operational conditions.The results showed that the breakthough time of chlorobenzene increased with increasing the specific surface areas and increase the saturated adsorption amount of chlorobenzene.Low temperature and high chlorobenzene concentration can increase the saturated adsorption amount of chlorobenzene.Comparing the modified active carbon,the active carbon modified by H₂O₂ had the highest saturatde adsorption amount of chlorobenzene up to 221.7mg/g due to the increasing of oxidative functional group.Harmless treatment for active carbon adsorption with chlorobenzene used low temperature thermal dechlorination method.Heating active carbon in N₂atmosphere at 340,380 and 400℃.The results showed high temperature improved the degradion rate of chlorobenzene.Loading CaO can improve the degradion of chlorobenzene.Heating active carbon at 380 for 4 h can reach the chlorobenzene degradion effiency up to 94%.