氟硅酸铵对小晶粒Y分子筛加氢裂化性能的影响  

Effects of(NH_4)_2SiF_6 treatment on performances of small crystal grain Y zeolite in hydrocracking

作　　者：于政敏 孙晓艳[1] 樊宏飞[1] 韩果[1] 

机构地区：[1]中国石化抚顺石油化工研究院,辽宁抚顺113001

出　　处：《石油化工》2016年第4期422-428,共7页Petrochemical Technology

摘　　要：采用不同浓度的氟硅酸铵溶液对小晶粒Y分子筛进行处理,考察了氟硅酸铵浓度对小晶粒Y分子筛物化性质和加氢裂化性能的影响。利用XRD,NH3-TPD,FTIR,SEM,27Al MAS NMR等手段对改性分子筛进行表征;以正十二烷为模型化合物考察催化剂的加氢裂化性能。实验结果表明,当氟硅酸铵浓度为0.3 mol/L时,NFY-3分子筛试样的结晶度和比表面积最大,继续地提高氟硅酸铵浓度会破坏分子筛的晶体结构;随氟硅酸铵浓度的增加,分子筛的脱铝量逐渐增大,分子筛表面的粗糙程度逐渐增加,总酸量逐渐减小,B酸与L酸的比先增大后减小;经0.3 mol/L氟硅酸铵溶液处理的NFY-3分子筛的B酸与L酸的比较适宜,表现出最优的加氢裂化活性,正十二烷转化率为79.54%,C4~8组分的选择性为59.65%。Small crystal grain Y zeolite was modified by treatment with ammonium fl uorosilicate solutions and then the modified zeolites were used in preparing hydrocracking catalysts. The infl uences of the ammonium f luorosilicate concentration on the physicochemical properties of the modif ied zeolites and the hydrocracking performances of the catalysts were investigated. The modified zeolite samples were characterizated by means of XRD,low-temperature nitrogen adsorption,NH3-TPD,FTIR,SEM and 27 Al MAS-NMR. The performances of the catalysts in the hydrocracking were evaluated with dodecane as model compound. The results showed that,the crystallinity and specific surface area of the modified zeolites reached the maximum at the ammonium fl uorosilicate concentration of 0.3 mol/L,and when the ammonium fl uorosilicate concentration sequentially increased the crystal structure of the Y zeolite was destroyed. With increasing the ammonium fl uorosilicate concentration,both the dealumination amount and the surface roughness of the zeolite samples gradually increased,the total acid amount decreased,and the ratio of B acid to L acid first increased and then decreased. Under the appropriate ratio of B acid to L acid,which could be reached by the treatment with 0.3 mol/L ammonium fl uorosilicate solution,the conversion and the selectivity to C4-8 in the hydrocracking over the catalyst were 79.54% and 59.65%,respectively.

关 键 词：小晶粒Y分子筛 氟硅酸铵 加氢裂化催化剂 

分 类 号：TQ426.6[化学工程]