Mo、W对Ni /Al2O3催化剂加氢脱氧性能的影响

采用γ-Al2O3栽体，通过浸渍法合成了Mo（W）-Ni／γ-Al2O3系列催化剂。以有机含氧化合物丁酸和丁醇为合成油品的模型化合物，在连续流动固定床反应器中考察了催化剂的加氢脱氧性能。结果表明，Mo（W）-Ni／Al2O3系列催化剂对丁酸和丁醇具有高的加氢脱氧性能；添加Mo（W）可有效地抑制NiO与栽体γ-Al2O3的强相互作用，显著降低催化剂的还原温度，增加催化剂的加氢脱氧活性；添加Mo比添加W的催化剂具有更高的加氢脱氧活性，MoNi6催化剂在280℃条件下，丁酸转化率100％，未完全加氢丁醇的质量分数仅为0．09％。     

共沉淀法制备Ni/Al2O3催化剂的研究

油脂加氢催化剂是以金属镍为活性组分、氧化铝为载体制备的Ni/Al2O3催化剂。在制备催化剂过程中,其合成条件直接影响着催化剂的最终活性。以工业硝酸镍、碳酸钠和自制氧化铝粉为原料,利用共沉淀的方法制备加氢催化剂,考察了反应温度、反应时间、反应液pH及反应过程中搅拌转速对催化剂活性的影响。通过实验数据汇总分析,最终确定制备Ni/Al2O3油脂加氢催化剂的最佳条件：反应温度为85 ℃、反应结束时溶液pH=8.0、反应时间为1.5 h、搅拌转速为600 r/min。在此条件下制备的Ni/Al2O3催化剂,经棕榈油加氢评价后测定的碘值最低。     

助剂Co对硫化氢与甲烷重整制氢Mo/Al2O3催化剂稳定性的影响

H2S与CH4重整制氢反应是一条新型的制氢技术路线,但目前用于该过程的高活性Mo/Al2O3催化剂存在着稳定性不佳的问题.以商业γ-Al2O3 (Al2O3)为载体,通过共浸渍方式在20％Mo/Al2O3催化剂中添加不同含量(质量分数为1％～20％)的Co助剂,在常压、反应温度为800℃、H2S和CH4体积比为1∶5、...     

磁场对Ni/Al2O3催化剂结构及加氢性能的影响

采用共沉淀法制备了Ni/Al₂O₃加氢催化剂,在制备过程中引入交流电磁场对催化剂做强化制备,通过BET、SEM、XRD和TPR等方法对催化剂做表征,并将该催化剂应用于脂肪酸加氢反应中,考察了磁场强度对催化剂结构及加氢性能的影响。结果表明,制备过程中引入电磁场能够有效降低催化剂颗粒的团聚,增大催化剂的比表面积和平均孔径,提高催化剂的脂肪酸加氢活性。随着磁场强度的增强催化剂还原温度逐渐升高,结构稳定性增强,有效延长了催化剂的使用寿命。     

对失活Co—Mo—D／Al2O3硫化物催化剂的剖析研究

本文通过多种测试技术研究了工业Co-Mo-K/Al2O3耐硫变换催化剂,失活样中各元素的存在状态,含量和物相变化。发现,在原催化剂中钾、,硫从内部向表面迁移并有流失,γ－Al2O3转变为（Al2O3)10R,MoS2,Co9S8变为含活性硫物种少的物相;从反应气中夹带的铁,铬,硅和镍杂质沉积在表面上,由此导致催化剂对H2O和CO的吸附与反应能力的下降,最终造成严重失活。     

W-Mo-Ni-Cr/Al2O3催化剂的表征及其加氢脱氮性能

采用X-射线衍射(XRD)、程序升温脱附(TPD)、程序升温还原(TPR)、红外光谱(IR)和气相色谱等技术,研究了Cr助剂对W-Mo-Ni/Al2O3催化剂的影响.结果表明,助剂Cr能有效改善催化剂中活性组分的分散状态,增加催化剂表面的B酸中心,可以提高催化剂的HDN反应活性.当催化剂中各原子比WMoNiCr=10.320.780.22、在氢分压1 MPa、反应温度180℃、反应时间1 h时,吡啶的单次转化率可达89%.     

润滑油加氢脱氮WMoNi/Al2O3催化剂的研究

以工业γ－Al2O3为载体，加入F作为酸性助剂，负载金属组分W、Mo和Ni，制成WMoNi/Al2O3润滑油加氢脱氮催化剂。轻大庆油150BS为原料，在小型实验装置上对该催化剂的加氢脱氮性能进行了考察。实验结果表明，在工业加氢精制条件下，精制油氮含量为3－6μg/g，加氢脱氮率为99．3％－99．6％，加氢脱氮效果良好。     

基于镁铝水滑石的Mo/Al2O3-MgO催化剂制备及其加氢脱硫性能

生产低硫或无硫柴油是当今世界范围内清洁燃料发展的趋势,加氢脱硫（HDS）是大规模生产清洁柴油最为有效的技术之一,而研制高活性的HDS催化剂成为该技术的关键。以镁铝水滑石与氧化铝的复合氧化物为载体,通过等体积浸渍法制备了一系列Mo/Al₂O₃-MgO催化剂,以二苯并噻吩（DBT）的正庚烷溶液为原料,在固定床反应器上评价所得催化剂的HDS活性,考察了不同镁铝比的水滑石、焙烧温度和添加量对催化剂物化性质和催化性能的影响。研究结果表明,镁铝比、焙烧温度和添加量均影响催化剂的酸性、金属还原性、硫化性能和MoS₂片晶的堆垛度等,当镁铝摩尔比为3、焙烧温度为800℃、成型时水滑石加入量为10%（质量分数）时,所制备催化剂的HDS活性最高,其脱硫率可达96.2%。这是由于该催化剂的酸性较适宜,活性组分与载体间的相互作用力适中,活性组分更易硫化,有助于提高MoS₂片晶的堆垛度进而改善催化剂的HDS性能。     

工业NiW/Al2O3催化剂上喹啉的加氢脱氮宏观动力学

以喹啉为含氮模型化合物,在高压滴流床反应装置中考察了工业NiW/Al2O3催化剂RN-10上的加氢脱氮动力学规律,研究了反应温度330～420℃、氢分压1.2～5.2MPa、氢油比200～800(v/v)、重量空速(WHSV)20～70 h-1等反应条件对喹啉的加氢脱氮反应结果的影响.结果表明,反应温度对喹啉的脱氮率影响较大,提高反应温度可有效提高喹啉的脱氮率;同时,氢分压也是喹啉加氢脱氮的一个重要的影响因素,但是,当氢分压和氢油比较大时,氢分压和氢油比的变化对喹啉的脱氮率基本无影响.采用修正的n(n＜1)级反应动力学模型对实验数据进行拟合,求得了喹啉加氢脱氮反应的表观活化能为180.4 kJ·mol-1.经检验,模型计算结果与实验结果能较好地吻合.     

裂解汽油一段加氢用Ni/Al2O3催化剂CS2中毒研究

采用固定床反应器研究了Ni/Al2O3上CS2对裂解汽油原料油中主要化合物芳烃、单烯烃和共轭烯烃加氢活性的影响,其对加氢抑制的顺序为:芳烃单烯烃共轭烯烃。XRD、XPS和IR表征分析表明,Ni/Al2O3催化剂失活的可能原因是CS2吸附在活性相表面,部分CS2碳硫键断裂发生氢解反应产生H2S和CH4,H2S与镍活性中心作用形成镍硫化合物。原料油中部分CS2吸附在催化剂表面,催化剂对共轭烯烃加氢也失去活性。     

Hydroisomerization of model FCC naphtha over sulfided Co(Ni)–Mo(W)/MCM-41 catalysts

Deep hydrodesulfurization (HDS) of gasoline generally brings about the saturation of olefins and leads to the serious octane number losses. Conversion of linear olefins to branched ones followed by hydrogenation to isoalkanes would minimize such octane number losses. In this work, MCM-41-supported Co–Mo, Ni–Mo and Ni–W catalysts were prepared by the incipient wetness impregnation method, and compared with an industrial Co–Mo/γ-Al₂O₃ catalyst. The surface acidities were measured by the techniques of microcalorimetry and infrared spectroscopy for the adsorption of ammonia, and probed by the reaction of conversion of isopropanol. The isomerization and hydrogenation of 1-hexene as well as the HDS of thiophene were studied by using model FCC naphtha. It was found that the sulfidation enhanced significantly the surface Brønsted acidity that favored the skeletal isomerization of 1-hexene under the HDS conditions. Since the isomerization and hydrogenation of 1-hexene are the two competition reactions, the catalysts with relatively lower hydrogenation activity may have higher selectivity to the isomerization reactions. The Co–Mo/MCM-41 showed the high selectivity to the skeletal isomerization reactions due to its strong surface Brønsted acidity and the relatively low hydrogenation activity. On the other hand, the Ni–Mo/MCM-41 exhibited high hydrogenation activity and therefore low selectivity to the isomerization reactions although it possessed quite strong surface Brønsted acidity. The Ni–W/MCM-41 exhibited the low activity for the HDS of thiophene and isomerization of 1-hexene due to the poor dispersion of active metals.     

一种提高Mo—Ni／Al2O3催化剂金属分散度的方法研究

提出了一种提高Ｍｏ－Ｎｉ／Ａｌ２Ｏ３催化剂金属分散度的方法，并采用ＸＰＳ及连续流动高压微反等手段进行考查和评价。研究结果表明，向浸渍液中加入适当的有机酸，要明显提高Ｍｏ，Ｎｉ的分散度，进而改善了催化剂的活性及选择性。     

氧化铝载体对镍/氧化铝催化剂性能的影响

氧化铝是化工催化行业广泛应用的催化剂载体。油脂加氢催化剂主要是以氧化铝为载体、镍为主要活性组分的催化剂。在制备镍/氧化铝催化剂的过程中,载体氧化铝使用的最佳条件：载体在共沉淀反应前加入,载体氧化铝比表面积为340.6 m2/g,载体氧化铝加入量为m（镍）∶m（氧化铝）=5∶4,反应的老化时间为45 min。在此条件下,制备的镍/氧化铝催化剂活性最高,应用效果最好。     

镍/三氧化二铝油脂加氢催化剂研究

以铝酸钠和硫酸铝为原料制备铝胶,然后将可溶性镍盐、稀土硝酸盐与碱性沉淀剂中和后,加入到上述铝胶中,经水洗、干燥、还原即制得油脂加氢催化剂。氧化铝载体比表面积为(300±10)m2/g时,催化剂活性最高;综合考虑温度对氧化铝载体比表面积及催化剂过滤性能的影响,选取85℃为最佳温度;还原气中氮气、氢气体积比为3∶1时,得到的催化剂活性最好。该催化剂的活性评价结果表明,其性能已达到进口产品的水平。     

Rationalizing the catalytic performance of γ-alumina-supported Co(Ni)–Mo(W) HDS catalysts prepared by urea-matrix combustion synthesis

A comparative study of the influence of Co (or Ni) promoter loadings and the effect of different sulfurizing agents and sulfurizing temperatures on the structure, morphology and catalytic performance of Mo- or W-based hydrodesulfurization (HDS) catalysts was carried out. Catalyst performance using a tubular fixed-bed reactor and the HDS of thiophene as a model reaction was evaluated. The oxidic and sulfurized states of the HDS catalysts were characterized by laser Raman spectroscopy, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and high resolution transmission electron microscopy (HRTEM). It has been found that the urea-matrix combustion (UMxC) synthesis is a simple tool for preparing supported catalysts in a short period of thermal treatment. Several consecutive stages such as urea melting, metal precursor dissolution and chemical reactions take place before and upon combustion process. The C₄H₄S/H₂-activated Co- (or Ni-) promoted MoS₂ (or WS₂) catalysts present a strong synergistic effect (SE) when the Co (or Ni)/Mo (or W) molar ratio is near to 0.5, whereas the C₄/C ₄ ⁼ molar ratios display a weak antagonistic effect. Alumina-supported Ni–W catalyst showed an optimal SE 2.5 times higher than those for Co (or Ni)-promoted Mo HDS catalysts. The kinetic parameters for thiophene-HDS reaction were also determined, suggesting that the C–S bond cleavage reaction for alumina-supported Co(Ni)–Mo HDS catalysts and H₂ activation reaction for Ni-promoted WS₂catalysts play an important role in the rate-limiting step.     

Ni/Al_2O_3覆膜方法

阐述了Ni/Al2 O3 复合颗粒在生产中的应用 ,讨论了在Al2 O3 陶瓷颗粒上形成Ni膜的三种方法 ,分析了这些方法的优缺点。     

Effects of small MoO3 additions on the properties of nickel catalysts for the steam reforming of hydrocarbons III. Reduction of Ni-Mo/Al2O3 catalysts

Ni/Al₂O₃ catalyst modified by small amounts of Mo show unusual properties in the steam reforming of hydrocarbons. There are no data about the effect of small amounts of molybdenum on reduction of the Ni-Mo supported catalysts. The properties of these very complex systems depend on the conditions of successive preparation stages (calcination, reduction) or the process conditions.

A series of Ni/Al₂O₃ catalysts modified by Mo were prepared in order to investigate the influence of promoter amounts and preparation sequence on their properties. Temperature programmed reduction (TPR) has been employed to study the reducibility of Ni-Mo/Al₂O₃ catalysts. Catalysts were further characterized by BET area, H₂ chemisorption and X-ray diffraction measurements.

The TPR curves of Ni-Mo/Al₂O₃ catalysts are very complex. Mo addition leads to the decrease of catalysts reducibility. However, complete reduction of NiO and MoO₃ can be achieved at 800 °C. The reduction course depends on the sequence of nickel and molybdenum addition into the support. Precise measurements of Ni peaks positions in the XRD pattern of Ni/Al₂O₃ and Ni-Mo/Al₂O₃ samples show the possibility of Ni-Mo solid solution formation.