Preparation And Performance Of Catalyst Of The Hydroisomorization Of The Light Hydrocarbon

The hydroisomerization of light paraffins is a very useful field of microporous molecular sieves -based catalysts in oil refining. Nowdays with the demand of environment protection more and more severe, the requirement to quality of automotive gasoline fuels is higher and higher.And the gasoline must be low of olefins, low of aromatic hydrocarbon and high of octane number. In our country, about 85% of automotive gasoline comes from the FCC oil, in which the content of alkene is very high about 45%, and most of the alkene is concentrated in light gasoline fraction. So the reduction in olefin content in gasoline maybe one of the vital techniques challenge to be settled. A post-treating process becomes a desirable schedule forachieving olefin reduction in the pool, however, traditional hydrofining technology can reduce the olefin, but it also will lead to octane loss. In this sense, hydroisomerization can be an alternative reaction to resolve the upper contradictory.With SAPO-11 zeolites of superior isomerization function as the support, prepare the Pd/SAPO-11 catalyst. It can transform the gasoline into isomerized objects to reduce olefin and another side to maintain high of the total octane.The supports are synthesized respectively by the hydrothermal method at lower temperature and adding crystal seed. At the former method the series of substituted AlPO-11 molecular sieves with shape selective pore path and expedient acidity, such as SAPO-11 and CoAPO-11 were synthesized. At the later way we got another kind of zeolite, AlPO-15 or eutectic zeolites with other different crystalliform molecular sieve. and the morphology and the particle size of the materials were estimated from scanning electron microscope(SEM) measurements, and the grain size were characterized by methords TEM. The result showed that SAPO-11 displayed spheric congeries,and the grain size was from 30nm to 100nm.And with the temperature rising, the grain size increased. In contrast, the topographic image of CoAPO-11 was very different from of SAPO-11.The Pd/SAPO-11 catalyst of low metal loding was prepared by impregnating method. The hydroisomerization of 1-butene, mixed butanes and n-hexane were selectively carried out in the fix bed reactor. The resultants were analysed by chromatogram equipment. The results showed the catalysts had some behavior of hydroisomerization to 1-butene and n-hexane. The acidity of SAPO-11 and Pd/SAPO-11 was characterized by Py-IR and NH3-TPD, correlated with the reaction results , the hydroisomerization happened on the middle-strong acid sites.