Study On H₂S Removal Characteristics Of CeO₂/ZnO/Multi-wall Carbon Nanotubes

Hydrogen sulfide（H₂S）is a harmful impurity in industrial gases such as natural gas,coke oven gas and semi-water gas.Industrial desulfurization is of great significance for corrosion prevention,air purification and production efficiency improvement.This thesis is based on the fact that reduced cerium oxide has high sulfidation activity,ZnO catalyst gas diffuses faster when passing through,and carbon nanotubes have the characteristics of extremely high strength,toughness and large specific surface area.ZnO/MWCNTs,CeO₂/MWCNTs,CeO₂/ZnO/MWCNTs composite materials for mine hydrogen sulfide removal.For the prepared ZnO/MWCNTs,CeO₂/MWCNTs,CeO₂/ZnO/MWCNTs composite materials,SEM observed that the surface of the zinc oxide was dens/e,and the wrinkles and holes were significantly reduced with the extension of the stirring time;the cerium oxide particles were adhered to the wall of the multi-walled carbon nanotubes,and as the Ce content was decreased,the density of the attached particles significantly was reduced;XRD and XPS physical characterization also show that cerium oxide and zinc oxide were loaded on multi-walled carbon nanotubes.XPS shows that with the decrease of doped Ce content,the relative content of Ce element in the composites decreased,and the Ce content of CeO₂/ZnO/MWCNTs（Ce:Zn:C=1:1:1）composite desulfurizer was relatively high.The fixed bed experimental platform constructed by removing hydrogen sulfide was mainly composed of temperature,flow control system,gas passage system,vaporizer,fixed bed reactor and data output system.Experiments were carried out this platform with successfully prepared ZnO/MWCNTs composite materials.The removal effect of hydrogen sulfide was analyzed under the condition of different metal doping amount,loading height,reaction temperature,reaction humidity,loading height,H₂S concentration,O2 concentration,CO2 gas concentration.Sulfur capacity was small when the loading height was close to the reactor inlet.Sulfur capacity,increased with the increasing temperature,was greatly influenced between 200℃ and 300℃,slightly influenced between 300℃ and 400℃.The sulfur capacity was increased as the H₂S concentration at the inlet increases;As the concentration of O2 in the reaction atmosphere was increased,the sulfur capacity of the three materials was increased;as the concentration of CO2 in the reaction atmosphere was increased,the sulfur capacity of the three materials was decreased.Zn:C=1:1 ZnO/MWCNTs composite has the largest sulfur capacity.For CeO₂/MWCNTs、CeO₂/ZnO/MWCNTs,The H₂S removal amount was the best when loaded in the middle of the reactor,The variation of H₂S removal amount under other influencing factors was similar to ZnO/MWCNTs.Relative to CeO₂/MWCNTs,the removal amount of CeO₂/ZnO/MWCNTs was increased slightly with the O2 concentration,decreased slightly with the concentration of CO2.CeO₂/ZnO/MWCNTs（Ce:Zn:C=1:1:1）was less affected by the reaction conditions with the largest removal amount.Under basic conditions,it’s H₂S removal amount is 158.76mg/g,which was 4.93%、8.59%higher than the materials of Ce:Zn:C=1:1:3 and Ce:Zn:C=1:1:5 and 12.24%、14.68%、18.34%higher than the materials of Ce:C=1:1、1:3、1:5.