Study On Ultra Deep Adsorption-desulfurization Of Diesel

With the development of fuel cell technology,it is necessary to produce an ultra-low sulphur diesel?S content<1?g/g?that can be used in fuel cells.Benzothiophene and dibenzothiophene are the main sulfur compounds in hydrogenated diesel.As the structure of such sulfide is stable,the method of hydrogenation is difficult to remove those sulfur compounds.The purpose of this study was to use non-hydrogenation and non-oxidized adsorption desulfurization technology to reduce the sulfur content in the national V standard diesel to below 1?g/g.Four different kinds of adsorbent were prepared by using activated carbon?AC?,alumina and boron nitride?BN?as the carrier.Inspecting the relationship between the loaded ration of different metal components,different metal content and adsorption capacity.The optimum temperature of each adsorbent was investigated.And the regeneration method of used adsorbents were also investigated in this paper.In addition,multiple techniques such as N₂ adsorption-desorption,SEM,XRD and NH₃-TPD,AAS,EDS were applied to characterize the textural,morphology,acid properties and adsorptive desulfurization performance of the adsorbents.After activated carbon is actived with nitric acid and impregnated with metals,the adsorption capacity of AC is improved,but it still cannot achieve the goal of ultra-deep desulfurization.Ni-based adsorbent works in need of high temperature.In order to reduce the temperature of adsorption,Cu was added to the Ni-based adsorbent.The sulfur content was reduced to 0.46?g/g at lower temperature by using Ni-Cu/?-Al₂O₃adsorbent than Ni/?-Al2O3 adsorbent.A single metal Ag/?-Al₂O₃ adsorbent was prepared,and it was able to reduce the sulfur content of diesel to about 1?g/g at room temperature.When the second metal Ti was added to Ag/?-Al₂O₃ to make Ag-TiO_x/?-Al₂O₃ adsorbent,the adsorption effect was improved,and the sulfur content of diesel was reduced to below1?g/g under the condition of the agent/oil ratio was 1:25.In the preparation of Ag-TiO_x/?-Al₂O₃ adsorbent,the using of ultrasonic can make the metal components more dispersed,thus improving the desulfurization effect of the adsorbent.Novel carbon boron nitride and metal-doped mesoporous carbon boron nitride?CBN and M-CBN?have also been prepared by using melamine and boric acid as the raw materials in this paper.When the adsorption temperature was 15?,the CBN showed the best adsorption performance.The CBN and M-CBN displayed a significantly high amount of acid sites and exhibited enhanced adsorption performance for sulfur compounds in hydrogenated diesel than pure carbon-doped boron nitride?CBN?.Ag-CBN with a mass fraction of 1.25%Ag can reduce the sulfur content of GB 19147-2016 automobile diesel fuel V to less than 1?g/g.