Preparation And Performance Of The Adsorbent Of NiO/ZnO（Al₂O₃-SiO₂）

With the high-speed of econom, a crowd of vehicles has stepped into peopleˊs daillife, air pollution caused by automobile exhaust gas which generate by the combustion ofthe sulfur-containing compounds become more and more seriously, moreover thecombustion of the sulfur-containing compounds also become one of the important reason ofthe generate of the weather of haze. Although the sulfur-containing compounds could beremoved effectively by the conventional hydro-desulfurization (HDS), the saturation ofolefins during HDS process will result in a significant decrease in octane number forgasoline, which leads to the decrease of anti-knock performance, and the investment of theequipment and the condition of the reaction were high. Thereactive adsorptiondesulfurization (RADS) occupied an important position because the low investment, andthe high desulfurization capability, furthermore, the octane number for gasoline changedlittle after the process.The adsorbents of NiO/ZnO(Al2O3-SiO2) were prepared by a precipitation methodwith ammonia solution as the precipitating agent, and investigate the temperature of thecalcinations, the content of NiO and the content of SiO2influence on the structure ofNiO/ZnO(Al2O3-SiO2)adsorbent in details, and the desulfurization performance evaluationof the adsorbents was carried out in a fixed bed reactor.The structure of the adsorbents were studied by the Infrared Spectroscopy, XRD andBET, NH3-TPD, the desulfurization capability and breakthrough time were13.46,30h,when the temperature was450°C, content of the active component was18wt.%andcontent of SiO2in the support was50wt.%. The Research Octane Number (RON) loss wasless than1.5units, and the rate of recovery was greater than98%. The main reaction in reactive adsorption desulfurization are the reforming ofnaphthenic hydrocarbon and the hydrogenation of olefins, hydrogenation of aromatics isalmost non-existent, so aromatics has little effect on the desulfurization performance ofadsorbents. The sulfur-containing compounds would be adsorbed on the surface of Ni,reacted to form NiS under the H2atmosphere, the reaction of NiS and H2to Ni and H2S,then ZnO reacted with H2S to yield ZnS.XRD, BET analysis showed that the sulfur-containing compounds reacted with Ni andZnO to yield NiS and ZnS, which decreased the reaction activity of the adsorbents, leadingto the decreasing of the adsorptivity and storage capacity of S, meanwhile, Ni3C wasformed during the desulfurization process, specific surface area of the adsorbents weredecreased because of the carbonization.