Zn/HZSM-5分子筛催化棕榈油多产芳烃的研究

Catalytic conversion of palm oil to aromatics on Zn/HZSM-5 zeolites

HZSM-5分子筛可用于脂肪酸酯催化转化生产芳烃、低碳烯烃等过程。未经过处理的HZSM-5分子筛芳烃产率较低,使用过渡金属改性后的HZSM-5分子筛酸性质发生了改变,能够提高芳烃的收率。以等体积浸渍法对HZSM-5分子筛进行改性,制备了不同锌含量的Zn/HZSM-5分子筛,并进行了XRD、XRF、XPS、NH3-TPD、SEM、TEM、Py-IR、N2物理吸附-脱附等多种表征,结果表明锌的引入没有改变HZSM-5的晶体结构,锌物种能均匀分布在HZSM-5分子筛表面及孔道。棕榈油催化转化实验结果显示Zn含量(质量分数)为3%的Zn/HZSM-5有最好的催化效果,芳烃在液相烃类所占比例(质量分数)为87.92%,芳烃收率(质量分数)为59.44%。

HZSM-5 zeolite can be used in the process of catalytic conversion of fatty acid esters to produce aromatic hydrocarbons and low-carbon olefins. However, the yield of aromatics over untreated HZSM-5 zeolite is low. Modification of HZSM-5 zeolite with transition metal can optimize the acidity and greatly increase the yield of aromatics. A series of Zn/HZSM-5 zeolites with different zinc content were prepared by equal volume impregnation, and the modified zeolites were characterized by XRD, XRF, XPS, NH3-TPD, SEM, TEM, Py-IR,and N2 physical adsorption-desorption. The results showed that the crystal structure of Zn/HZSM-5 was not changed, and the zinc was uniformly distributed on the surface and pores of HZSM-5 zeolites. Catalytic conversion of palm oil on Zn/HZSM-5 zeolite with Zn content of 3%(mass) showed the best catalytic performance. The content of aromatics in the obtained liquid hydrocarbons was as high as 87.92%(mass), and the yield of aromatics reached 59.44%(mass).