催化剂载体的表面改性与加氢脱硫性能评价

MODIFICATION AND EVALUATION OF THE CATALYST SUPPORT ON HYDRODESULFURIZATION

采用沸石的次级结构单元(或称分子筛纳米簇)对γ-Al2O3进行表面改性,制备具有强酸性和较大孔道结构的催化剂载体。采用NH3-TPD、Py-IR、XRD、BET、HRTEM等手段对改性γ-Al2O3进行表征。采用浸渍法,以改性γ-Al2O3为载体制备负载型加氢精制催化剂。以4,6-二甲基二苯并噻吩(4,6-DMDBT)为模型化合物,在高压微型反应器中对其加氢脱硫(HDS)催化活性进行评价。结果表明,改性后γ-Al2O3的酸强度明显提高,其物理性质变化不大,分子筛纳米簇均匀地分散于γ-Al2O3表面。与以未经改性γ-Al2O3为载体的催化剂相比,以分子筛纳米簇改性γ-Al2O3为载体的催化剂,硫化态金属组分的堆垛层数明显增大,4,6-DMDBT的HDS转化率和脱硫率显著提高,脱硫率/转化率的比值增加明显,具有较高的加氢脱硫活性。

The support with high acidity and large porous channel was prepared through surface modification of γ-Al2O3 with the secondary structural building units（zeolite nanoclusters）.The structure and properties of modified γ-Al2O3 were characterized by NH3-TPD,Py-IR,XRD,BET and HRTEM.The modified γ-Al2O3 supported hydrogenation catalysts were prepared with dip treatment,and their catalytic activity for hydrodesulfurization（HDS） was evaluated in a high pressure micro-reactor with 4,6-dimethyldibenzothiophene（4,6-DMDBT） as the model compound.The results showed that the acidity of the modified γ-Al2O3 was greatly improved and β zeolite nanoclusters could be uniformly dispersed on the surface of γ-Al2O3,while the surface,pore diameter and pore volume of modified γ-Al2O3 were changed little.Compared with catalyst supported by unmodified γ-Al2O3,the dump of active component was increased greatly,and the conversion and desulfurization of 4,6-DMDBT over modified γ-Al2O3 supported catalyst were improved remarkably,and the ratio of desulfurization to conversion was raised obviously,which meant that this kind of catalyst had high activity of hydrodesulfurization for 4,6-DMDBT.