沉淀剂对体相加氢催化剂物化性质和活性的影响

EFFECT OF DIFFERENT PRECIPITATING AGENTS ON PHYSIC-CHEMICAL PROPERTIES AND ACTIVITY OF BULK HYDROGENATION CATALYSTS

分别选用NH_(3)·H_(2)O,NaOH,Na_(2)CO_(3)以及不同配比NaOH和Na_(2)CO_(3)混合液作为沉淀剂制备一系列体相催化剂;采用X射线衍射、N_(2)吸附-脱附、扫描电镜、透射电镜、电子探针等表征方法和小型加氢装置评价手段,考察不同沉淀剂和不同沉淀剂配比对体相加氢催化剂物化性质和活性的影响。结果表明:采用单独一种沉淀剂时,由NaOH合成的体相催化剂压碎强度和孔结构最优,活性金属分散均匀,加氢脱硫活性最高;采用NaOH和Na_(2)CO_(3)的混合沉淀剂对体相催化剂有扩孔作用,可使催化剂性能提升;在混合沉淀剂配比为m(Na_(2)CO_(3))∶m(NaOH)=2∶3时催化剂物化性质和活性最佳,此时催化剂比表面积为213 m^(2)/g,孔体积为0.308 cm^(3)/g,堆密度为1.01 g/cm^(3),压碎强度为14.9 N/mm,相对脱硫活性为采用NaOH为沉淀剂的催化剂的1.66倍。

A series of bulk catalysts were synthesized by using NH_(3)·H_(2)O,NaOH,Na_(2)CO_(3) and mixtures with different ratios of NaOH and Na_(2)CO_(3) as precipitating agents.Characterization methods such as XRD,BET,TEM,SEM and EPMA are used to analyze the microscopic morphology,pore structure,crushing strength and phase of the synthesized catalysts;and a series of bulk catalysts are evaluated for hydrodesulfurization activity on a small hydrogenation unit.The results show that when a single precipitating agent is used,the bulk catalyst synthesized with NaOH has the best crushing strength and pore structure,the active metal is evenly dispersed,and its hydrodesulfurization activity is the highest.The mixed precipitating agent of NaOH and Na_(2)CO_(3) can expand the pores of the bulk catalyst,which can improve the performance of the catalyst.When the mixed precipitating agent is m(Na_(2)CO_(3))∶m(NaOH)=2∶3,the catalyst has the best physical and chemical properties and activity,the specific surface area of the catalyst is 213 m^(2)/g,the pore volume is 0.308 cm^(3)/g,the bulk density is 1.01 g/cm^(3),and the crushing strength is 14.9 N/mm.The relative desulfurization activity of the bulk catalyst at this ratio is 1.66 times that of the catalyst using NaOH as the precipitating agent.