| Mercury is highly toxic pollutant with volatility,bioaccumulation and persistence in the environment.Coal combustion is the main source of anthropogenic mercury emissions,and it is of great significance to select economically and efficiently the removal of trace Hg~0 from coal combustion flue gas.Activated carbon injection(ACI)mercury removal technology is more mature,but due to the high cost of removal is limited.Therefore,this paper will be adsorbent removal technology and the existing dust removal equipment to combine the use of bag filter dust removal mercury integration effect is better than the characteristics of electrostatic precipitator,bag filter in the five commonly used filter: HuaboTe(HBT)filter,polytetrafluoroethene(PTFE)filter,polyphenylene sulfide(PPS)fiber filter,Fumex(FMS)filter,polysulfonamidefibre(PSA),the removal effect of trace Hg~0 in flue gas;In order to reduce the cost of mercury removal,a renewable magnetic silver-loaded filter was prepared and characterized,and the removal effect of trace Hg~0 in flue gas was studied;The adsorption isotherms of the magnetic silver-containing filter were fitted by Langmuir and Freundlich models,and the dynamic analysis of the magnetic silver filter was carried out before and after the adsorption-regeneration.Firstly,five kinds of high temperature resistant inorganic filter are selected by 20% HCl,HBT filter,polytetrafluoroethylene(PTFE)filter,polyphenylene sulfide(PPS)fiber filter,Fumex(FMS)filter,polysulfonamidefibre(PSA)filter are used,and(MagF-Ag0)was prepared by impregnation method,and the performance was characterized by different methods.The magnetic filter was prepared by coprecipitation method.The results show that the removal effect of Hg~0 on the microstructure of the surface is related to the surface microstructure by scanning electron microscopy(SEM);By infrared spectroscopy(ATR-FTIR)analysis,it was shown that there was a strong oxidative oxygen-containing functional group on the surface of magnetic silver-containing HBT filter,which was favorable for Hg~0 adsorption,Such as C=O,C-O and-SH;The XRD characteristics show that the magnetic silver-containing media contains Fe3O4 and Ag,and the crystallinity is good;By XRF qualitative semi-quantitative analysis,it can be seen that the magnetic silver-containing HBT filter contains 30.43% carbon content,15.77% oxygen content,6.83% Fe element and 5.97% Ag element,which proves that the magnetic silver is successful.Based on the successful loading of the filter media,the effects of five kinds of filter media and five kinds of magnetic silver filter on the removal of trace Hg~0 in simulated flue gas were investigated.The effects of adsorption temperature,Hg~0 inlet concentration and flue gas on the removal of trace Hg~0 in simulated flue gas.The results show: the mercury removal efficiency of HBT filter was the highest in the five kinds of filter media,the initial adsorption efficiency was 44.31%;The mercury removal efficiency of magnetic silver-loaded HBT filter was the highest,and the initial adsorption efficiency was 84.97%;the removal efficiency of Hg~0 by magnetic silver-containing HBT filter increases with the increase of flue gas temperature,and then decreases with the increase of Hg~0 inlet concentration;the presence of SO2 in the presence of HCl,NO,O2 promotes the adsorption of Hg~0 by magnetic silver-containing HBT media,which inhibits the adsorption of Hg~0.In addition,the regeneration performance of magnetic silver-containing HBT filter with the highest mercury removal efficiency under N2 atmosphere was studied in this paper.The effects of regeneration temperature and regeneration times on the adsorption Hg~0 efficiency were investigated;The Langmuir model was used to fit the adsorption isotherms of five kinds of magnetic silver-loaded media,and the Langmuir and Freundlich models were used to evaluate the adsorption isotherm of the largest amount of adsorption magnetic silver-loaded HBT filter.And the kinetic model was used to study the adsorption of Hg~0 by magnetic silver-loaded HBT filter before and after adsorption-regeneration.The results show: The mercury removal efficiency of the magnetic silver-containing HBT filter after regeneration is reduced,when the regeneration temperature is 160?,240? and 300?,with the increase of regeneration temperature,the adsorption efficiency increases;with the increase of the number of cycles,the adsorption efficiency increased slightly and then decreased;Langmuir has a high correlation for the adsorption of Hg~0 from five magnetic silver-loaded media,and Langmuir adsorption model can better describe the adsorption process of magnetic silver-containing HBT filter on Hg~0 relative to Freundlich adsorption model.The quasi-second-order kinetics model can better describe the adsorption process of Hg~0 for the first adsorption-regeneration of magnetic silver-containing HBT filter media;The quasi-first-order kinetics model can better describe the adsorption process of the magnetic silver-containing HBT filter after five adsorption-regeneration reactions to Hg~0. |
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