重质油大分子在模型催化剂中扩散行为的研究

摘要

Using F127 as template agent,tetraethyl orthosilicate as silicon source,a series of meso-poreous silica FDU-1 2 s as model catalysts were synthesized under different conditions for investigation of diffusivity of asphaltene.The catalysts were characterized by BET,XRD,TEM,SEM techniques.The influence of assemble temperature and crystallization temperature on the pore size of the materials was investigated.The diffusivities of asphaltene in the catalysts with different pore size were studied.The results show that rising the crystallization temperature can only enlarge the pore mouth size of FDU-1 2 molecular sieves without the increase of cage diameter,while lowering the assemble tempera-ture has a opposite effect.Increase of entrance pore size and cage size of FDU-1 2 enhances the effective diffusivity;however,the decrease of specific surface due to excessive increase of pore size can reduce ef-fective diffusivity.%采用F127为模板剂、正硅酸四乙酯为硅源，经水热法合成了 FDU-12介孔分子筛，将其作为模型孔道催化剂用于沥青质的扩散研究。通过N2吸附-脱附、XRD、TEM、SEM等对 FDU-12进行表征。结果表明：升高晶化温度能够增大催化剂孔道的入口孔径，而笼孔径不变；降低组装温度能够增大分子筛的笼孔径，而入口孔径不变。运用吸附扩散法测定了沥青质在模型孔道催化剂中的有效扩散系数。结果表明：增加模型催化剂的入口孔径和笼孔径在一定范围内能够提高有效扩散系数，但是孔径过大会导致载体的比表面积下降，使有效扩散系数降低。