| Activated coke flue gas desulfurization technology is a dry process flue gas desulfurization technology,which mainly utilizes the developed pore structure of activated coke and the acid and alkaline functional groups on the surface to adsorb and catalyze the oxidation reaction to achieve flue gas desulfurization.Activated coke,as a key material of activated coke flue gas desulfurization technology,is a key factor affecting the desulfurization effect and economic performance of this technology.In this paper,fine semi-coke and low metamorphic coal are used as raw materials.Phenolic resin,sodium humate and sodium-based bentonite were selected as binders.The orthogonal method was used to determine the optimal composite binder addition ratio.Based on the characterization and analysis of SEM,FT-IR and TG-DTG,the size and source of the cohesive force during activated coke forming and carbonization were revealed,and the adsorption conversion and occurrence mechanism of SO2 in activated coke were discussed.Studies have shown that the addition of composite binders can improve the compressive strength of activated coke while regulating the pore structure and increase the adsorption value of iodine.When the addition amount of phenolic resin was 10%,the addition amount of sodium humate was 15%,and the addition amount of sodium-based bentonite was 5%,the indicators of activated coke are better.At this time,the yield was 67.22%and the compressive strength was 200.80 N,the iodine adsorption value was 531.40 mg/g,the ash content was 20.00%.During the formation of activated coke,particles were mainly affected by the combined effects of van der Waals force,adhesion force,hydrogen bonding force and capillary force.In the absence of binder,the main source of bonding force was the hydrogen bonding force formed by raw material and water,and the amount of water added and the oxygen functional groups on the surface of raw material have a great influence on the hydrogen bonding force.In the presence of binder,the adhesive force dominated by the viscosity of binder has a great influence on the strength of molding material.The TG-DTG curves of the comparative samples were analyzed and found that during the carbonization process,the initial temperature?323??of the vigorous pyrolysis of the molding material is less than the mixed raw material?365??and the final temperature?571??of the vigorous pyrolysis is greater than the mixed raw material?529??.Compared the TG curves of the two samples,it was found that the presence of the composite binder prolongs the pyrolysis time,and the weight loss rate of the molding material was 2%higher than that of the mixed material.In the carbonization process of the molding material,the composite binder pyrolyzes and produces colloids before the mixed raw materials,and bonding and colloid solidification occur between the raw material particles,thereby playing the role of bonding.When using a fixed-bed reaction system to examine the adsorption performance of self-made activated coke and the adsorption-transformation path of SO2,It is found that the conversion of SO2 to SO3 is the role of O2 molecule,which is in accordance with the E-R model,that is,the single active site reaction mechanism.The addition of O2promotes the oxidation reaction of SO2,thereby enhancing the desulfurization effect of activated coke.The transient response experiment was combined with the infrared spectrogram of activated coke under different gas phase components.It is believed that when O2 and H2O exist at the same time,SO2 first adsorbs and catalyzes in micropores to generate SO3,and H2O participates in the reaction to generate H2SO4.The connection structure of micropores,mesopores and macropores provides space for the reaction products to promote the adsorption of SO2 by activated coke.At the same time,the presence of O2 and H2O in the gas phase components has a positive effect on improving the desulfurization efficiency of activated coke,with the highest desulfurization rate up to 96%. |
PDF Full Text Request