γ-氧化铝的水热法合成及NiMo/γ-Al2O3催化剂的加氢脱硫性能

摘要

Ammonium aluminum carbonate hydroxide(AACH) as the precursor ofγ-alumina was hydrothermally synthesized from pseudo boehmite and ammonium bicarbonate solution,and NiMo/γ-Al2O3 was prepared by impregnation. AACH,γ-Al2O3 and NiMo/γ-Al2O3samples were characterized by means of XRD,BET,SEM,27Al MAS NMR,Py-IR and HRTEM. The influences of ammonium bicarbonate concentration and hydrothermal reaction time on the AACH preparation were researched and the performances of the NiMo/γ-Al2O3 catalyst in hydrodesulfurization were inestigated. The results indicated that,rod-like AACH with high crystallinity could be synthesized under the conditions of NH4HCO3 2.00 mol/L and hydrothermal time 8 h,and the synthesizedγ-Al2O3 support had larger specific surface area,pore volume and pore diameter thanγ-Al2O3 prepared directly from pseudo boehmite. Under the conditions of hydrogen pressure 2 MPa,LHSV 4.0 h-1 andV(H2):V(Oil) 300,the conversion of dibenzothiophen in the hydrodesulfurization over the NiMo/Al2O3-AC catalyst reached 76.12%.%以拟薄水铝石为原料,采用水热法合成载体γ-Al2O3的前体碳酸铝铵(AACH),利用XRD,BET,SEM,27Al MAS NMR,Py-IR,HRTEM等手段对AACH、γ-Al2O3试样(Al2O3-AC)和NiMo/γ-Al2O3催化剂进行表征,考察了碳酸氢铵浓度和水热时间对制备AACH的影响,研究了催化剂的加氢脱硫性能.表征结果显示,在NH4HCO3浓度为2.00 mol/L、水热时间8 h条件下制备的AACH为棒状颗粒结构,结晶度较好;载体Al2O3-AC具有较大的比表面积、孔体积和孔径; NiMo/Al2O3-AC催化剂硫化后MoS2颗粒分布均匀,活性相中出现了较多Ⅱ型的Ni—Mo—S相,具有较好的加氢脱硫活性.实验结果表明,在LHSV=4.0 h-1、V(H2):V(油)=300、氢压2 MPa条件下,NiMo/Al2O3-AC催化剂催化二苯并噻吩脱硫率达76.12%.