水热处理温度对纳米CoMo/HZSM-5催化剂选择加氢脱硫性能的影响

EFFECT OF HYDROTHERMAL TREATING TEMPERATURE ON THE SELECTIVE HYDRODESULFURIZATION PERFORMANCE OF CoMo/NANO-HZSM-5 CATALYSTS

在不同温度下对纳米HZSM-5进行水热处理,并采用XRD、NH3-TPD、吡啶吸附FT-IR和N2吸附等方法对其进行表征,考察不同水热处理温度对纳米HZSM-5的结构、酸性、比表面积和孔体积等物化性质的影响。在连续流动固定床装置上,以全馏分FCC汽油为原料,考察经不同温度水热处理并负载活性组分Co、Mo后,纳米CoMo/HZSM-5催化剂在汽油加氢改质中的催化性能。结果表明,纳米HZSM-5具有良好的水热稳定性;水热处理后其酸强度与酸量均有所降低,活性组分与载体间的相互作用有所增强。提高水热处理温度会抑制催化剂的加氢脱硫活性,催化剂的烯烃饱和活性也大幅度下降。当处理温度高于600℃时,烯烃饱和率小于5%,产物族组成基本保持不变。

A series of modified nanosized HZSM-5 samples were prepared by hydrothermal treatment under various temperatures. The effects of hydrothermal treating temperatures on the structure and properties of nanosized HZSM-5 samples, such as acidity, surface area and pore volume were investigated by XRD,NH3-TPD,pyridine FT-IR and N2 adsorption/desorption techniques. The catalytic performance of these nanosized HZSM-5 samples incorporated with CoMo active components was evaluated on a con- tinuous-flow fixed bed micro-reactor using full range FCC gasoline as feedstock. Results showed that nanosized HZSM-5 exhibited good hydrothermal stability after hydrothermal treatment its acid amount and acid strength reduced, the interreaction of active components and support enhanced. With the increase of hydrothermal treating temperature,the hydrodesulfurization activity of the catalyst decreased, however,the olefin saturation activity decreased as well, more olefins remained in the treated gaso- line. When the hydrothermal treating temperature was more than 600℃, the olefin saturation rate was less than 5%, so that the group compositions of the treated gasoline were basically unchanged.