Preparation And Arsenic Removal Application On Copper-based Silicate Catalyst

In recent years,China has made great achievements in the research of arsenic removal from oil,especially in the field of hydro-arsenic removal.However,because FCC gasoline and other light oils contain a large number of unsaturated hydrocarbons,the temperature and pressure of hydrogenation and arsenic removal are relatively high.In the process of reaction,not only the octane number of gasoline is reduced,but also side reactions like coking,which deactivates the catalyst and blocks equipment.Recently,researchers have turned their attention to the method of arsenic removal at room temperature.Chemical adsorption is the main method for arsenic removal at room temperature.The combination of arsenide and activity results in electron cloud migration,which is adsorbed on the surface of carrier.From the analysis of current research results,the quality of arsenic removal catalyst and its performance mainly depend on the chemical nature between arsenide and arsenic removal active phase,volume factor of arsenide and petroleum hydrocarbon and pore structure factor of arsenic removal catalyst.In this paper,copper phyllosilicate were prepared by ammonia evaporation method.Meanwhile,the effect of preparation conditions on the texture properties of Cu/SiO₂ was investigated by orthogonal test,and the optimal combination of texture properties was obtained.The effects of copper source and calcination temperature on the species formation and texture properties of copper silicate were further investigated.On this basis,the carrier Al₂O₃-SiO₂ was prepared by coprecipitation method,and the arsenic removal effects of industrial catalyst（10%Cu/AC）、Cu/Al₂O₃-SiO₂、Cu/SiO₂、Fe-Cu/SiO₂、Mn-Cu/SiO₂ and Cr-Cu/SiO₂ on Daqing atmospheric top oil were investigated.The evaluation results showed that the arsenic removal rate of industrial catalyst is 94.99%,Cu/SiO₂ is 96.02%,Fe-Cu/SiO₂ is 97.35%,Mn-Cu/SiO₂ is 99.01%,and Cr-Cu/SiO₂ is 99.19%.From the characterization methods of BET、XRD、TEM、SEM、FT-IR、XRF and H₂-TPR,it can be concluded that Cu/SiO₂ has highly dispersed copper species,more suitable pore size distribution and larger specific surface area,which is more conducive to the internal diffusion of arsenide.Adding more active sites in the process of arsenic removal by adsorption is the key to the excellent performance of arsenic removal.At the same time,in the experiments of active metals with different oxidation performance on Cu/SiO₂ as the precursor,the supported active metals will further promote the dispersion of copper species in the catalyst,and the arsenic removal performance of Me-Cu/SiO₂ had been further improved.The performance of arsenic removal increasesed with the increase of the oxidation performance of Me.For the Cu/Al₂O₃-SiO₂,the selective adsorption performance of Cu²⁺on different forms of organic arsenic was studied.Through the experiment,characterization and density functional theory calculation,it was found that the removal rate of Daqing atmospheric tower oil with distillation and cutting fraction>135℃was relatively optimal,and the removal rate was79.06%.When arsenide in the form of R-As reacts with Cu²⁺,the interaction energy between arsenide and Cu²⁺decreases with the increase of the number of carbon atoms in-R,and a more stable complex was formed.Therefore,the best removal effect for>135℃fractions in Daqing atmospheric tower oil was shown.