柠檬酸对CoMo/Al2O3催化剂中助剂作用的影响

在一系列不同体相原子比[n(Co)/ n (Co+Mo)]的CoMo/Al2O3催化剂制备过程中引入柠檬酸,考察了柠檬酸对CoMo催化剂中助剂作用的影响,并采用BET,XRD,XPS,HRTEM等手段进行表征。结果表明：柠檬酸可以提高助剂Co和主剂Mo在载体表面的分散性,使Co对MoS2的助剂作用增强,这种促进作用在较高体相原子比时更加明显;在4,6-二甲基二苯并噻吩加氢脱硫反应中,催化剂的加氢脱硫活性均随助剂含量的增加表现出先增后减的趋势,且在体相原子比为0.3时达到最高;添加柠檬酸后催化剂的脱硫活性提高,且在较高体相原子比时活性提高更为明显。     

RS-1100柴油加氢脱硫催化剂的研制

采用合适的拟薄水铝石制备氧化铝载体,并以浸渍法制备NiMo/Al2O3催化剂,找到催化剂中适宜的Ni/(Ni+Mo)原子比,在浸渍液中引入适量的助剂和有机络合剂可以提高NiMo/Al2O3催化剂的活性。采用拉曼光谱和紫外-可见光谱仪对浸渍液进行了表征,结果表明浸渍液中存在杂多酸阴离子[P2Mo5O23]6-;络合剂与Ni离子也存在相互作用。通过制备条件优化,研制出高活性加氢脱硫催化剂RS-1100。中型装置评价结果表明,RS-1100催化剂的柴油超深度加氢脱硫活性比工业参比剂RS-1000更高,采用RS-1100催化剂在合适的加氢反应条件下可以生产满足欧Ⅴ排放标准的柴油。     

NiV/Al_2O_3催化剂的渣油加氢活性研究

以孔饱和浸渍法制备不同Ni/(Ni+V)原子比的NiV/Al2O3催化剂,并对催化剂进行拉曼光谱和H2-程序升温还原(H2-TPR)表征。以科威特常压渣油为原料,考察不同Ni/(Ni+V)原子比的NiV/Al2O3催化剂的渣油加氢脱金属和脱硫活性。研究结果表明:Ni可促进V的聚集,减弱V与载体间的相互作用;Ni与V具有协同作用,Ni/(Ni+V)原子比为0.25时,催化剂的渣油加氢脱金属活性明显高于其它Ni/(Ni+V)原子比的催化剂,渣油加氢脱硫活性略高于其它Ni/(Ni+V)原子比的催化剂。     

加氢脱硫CoMo/Al_2O_3催化剂的原位FTIR表征

采用等体积浸渍法制备了Mo/γ-Al2O3和CoMo/γ-Al2O3硫化态催化剂,利用原位FTIR方法对催化剂吸附CO前后的结构进行了表征,分析了催化剂活性中心的变化规律。表征结果显示,Mo/γ-Al2O3催化剂中存在未改性的MoS2吸附相;CoMo/γ-Al2O3催化剂中由于加入了助剂Co,可使部分MoS2相转变为CoMoS相,且分散度较高;CoMoS相的形成可增加催化剂活性位的数量、提高催化剂的加氢脱硫(HDS)活性。当CoO含量为3.1%(w)时,CoMo/γ-Al2O3催化剂对4,6-二甲基二苯并噻吩的HDS活性最高,达到56%。     

尿素燃烧法Co-Mo/Al_2O_3-TiO_2催化剂的加氢脱硫性能

以尿素燃烧法制备了Co-Mo/Al2O3-TiO2催化剂,采用低温N2吸附、HRTEM、XPS等方法对催化剂的表面结构和电子状态进行了表征,在微型固定床反应器上对Co-Mo/Al2O3-TiO2催化剂的活性进行了评价。考察了尿素添加量、TiO2添加量、n(Co)∶n(Mo)、反应温度和液态空速(LHSV)等对催化剂结构和加氢脱硫活性的影响。实验结果表明,采用n(尿素)∶n(Co+Mo)=10.0时制备的Co-Mo/Al2O3-TiO2催化剂表面负载的金属组分密度大,孔径大,对二苯并噻吩的脱除率达94%以上;添加TiO2降低了Mo与载体的相互作用;在Al2O3-TiO2载体中TiO2的质量分数为20%,n(Co)∶n(Mo)=0.35~0.55、反应温度300~380℃、LHSV=3~6h-1的条件下,Co-Mo/Al2O3-TiO2催化剂的加氢脱硫活性最好。     

免焙烧的CoMo-CA/Al_2O_3加氢脱硫催化剂的制备与表征

以柠檬酸为络合剂,制备了稳定的Co Mo浸渍液Co Mo-CA(CA表示柠檬酸),将其浸渍于γ-Al2O3载体上制备了免焙烧的Co Mo-CA/Al2O3催化剂,采用UV-Vis、FTIR、N2吸附-脱附、H2-TPR和HRTEM等手段对催化剂进行分析与表征;以直馏柴油为原料,在高压微反装置上评价了催化剂的加氢脱硫和加氢脱氮活性。实验结果表明,Co Mo-CA浸渍液中柠檬酸不能置换出[Co(H2O)6]2+中的水分子形成新的Co2+-柠檬酸配合物;柠檬酸与活性组分M o形成配合物,提高了溶液的稳定性。免焙烧的Co Mo-CA/Al2O3催化剂中活性组分Mo以金属配合物的形式存在,柠檬酸在硫化过程中逐步分解,有利于降低活性组分与载体的相互作用,Mo的硫化变慢,避免形成难硫化的Mo物种,有利于Ⅱ型Co-Mo-S活性相的形成。在所考察的评价条件范围内,免焙烧的Co Mo-CA/Al2O3催化剂的加氢活性优于焙烧后的催化剂。     

Zr改性CoMo/TiO2-SiO2催化剂的结构和脱硫性能研究

由四氯化钛气相沉积在粗孔硅胶表面上制备钛硅复合氧化物载体,之后负载活性组分Co、Mo制备CoMo/TiO2-SiO2加氢脱硫催化剂,同时对催化剂用硫酸锆进行了改性,改性后对噻吩的脱硫活性有了很大的提高,脱硫率由88.62%上升到了99.41%,为了揭示不同方法获得催化剂活性差别的结构原因,对催化剂中Mo原子的K边进行了XAFS分析,分析结果表明改性前后催化剂的活性组分Mo原子的第一配位层Mo-S的配位数减小,相当于在Mo原子周围存在更多的硫空穴,增加了吸附噻吩的能力.因此增加催化剂对噻吩加氢脱硫活性.     

MoS3/Al2O3复合材料的合成及其用于制备加氢催化剂的研究

采用液相反应沉积法合成MoS3/Al2O3复合材料,考察了不同反应温度、反应物浓度、反应时间、体系pH值及不同类型分散剂对MoS3在γ Al2O3载体表面沉积量的影响,并采用MoS3/Al2O3复合材料为助剂Co的第2载体制备了CoMo硫化态加氢脱硫催化剂;采用XRF、XRD、XPS、TEM、BET等分析手段对MoS3/Al2O3复合材料及CoMo硫化态和氧化态催化剂进行了表征。结果表明,采用乙醇为分散剂,钼酸钠摩尔浓度为01~1 mol/L、在反应温度85~120℃、体系pH值1~2、反应8~24 h条件下,可以合成MoS3沉积量为628%~868%（以MoO3质量分数计）的MoS3/Al2O3复合材料;与常规氧化态催化剂相比,所制备的CoMo硫化态催化剂具有更高的加氢脱硫活性。     

CoNiMo/MCM-41催化的二苯并噻吩加氢脱硫反应

 以质量分数为0.8 %的二苯并噻吩（DBT）的十氢萘溶液为模型化合物，考察了全硅MCM-41担载的CoMo、NiMo以及CoNiMo硫化物催化剂的加氢脱硫（HDS）反应性能。结果表明，DBT在NiMo/MCM-41催化剂上主要通过加氢反应路径脱硫，而在CoMo/MCM-41和CoNiMo/MCM-41催化剂上主要通过直接脱硫反应路径脱硫。NiMo/MCM-41催化剂的HDS活性远高于CoMo/MCM-41或CoNiMo/MCM-41催化剂。CoNiMo/MCM-41催化剂反应性能与CoMo/MCM-41催化剂相似，没有观察到明显的双助剂效应。根据紫外-可见漫反射光谱（UV-Vis）的测定结果，Co与Mo之间的相互作用比Ni与Mo之间的相互作用强，在CoNiMo/MCM-41催化剂中Co会优先与Mo结合，形成与CoMo/MCM-41催化剂中类似的活性相，表现出与CoMo/MCM-41催化剂相似的催化特性。     

硫化态Co-Mo/Al_2O_3-MgO催化剂的红外光谱研究

采用双探针 (CO ,CO +NO)红外光谱方法对Co/Al2 O3、Mo/Al2 O3、Co Mo/Al2 O3、Co/Al2 O3 MgO、Mo/Al2 O3 MgO及Co Mo/Al2 O3 MgO催化剂进行研究 ,结果表明 ,在载体Al2 O3上 ,活性组分Co、Mo与载体之间的相互作用较强 ,而在载体Al2 O3 MgO上 ,活性组分Co、Mo与载体之间的相互作用适中 ,且活性组分Co、Mo之间存在协调作用 ,提高了催化剂的变换活性。     

非负载Co-Mo催化剂的制备、表征与加氢脱硫活性评价

采用溶胶-凝胶法制备了Co-Mo超细复合氧化物,进而制得了非负载型Co-Mo催化剂;采用XRD、IR、BET、SEM等考察了n(A1):n(Co+Mo)、n(Mo):n(Co+Mo)和CA(柠檬酸)/(Co+Mo)的摩尔比对对应催化剂的表面形貌、结构和催化性能的影响.结果表明:制备的非负载催化剂以β-CoMoO<,4>...     

IRON COMPOUNDS AND C0-Mo/Al2O3 CATALYSTS: ACTIVITY IN DIRECT HYDROGENATION OF A SUBBITUMINOUS A COAL WITH AN H-DONOR SOLVENT

The effectiveness of different catalysts were compared in coal liquefaction experiments using a 250 ml stirred autoclave, 10 g of a Spanish Subbituminous A coal, 1 hour reaction time, 17 MPa operating pressure, 400 rpm stirring speed, at 425 and 450 °C with 2/1 and 3/1 tetralin/coal ratio. The liquefaction products were fractionated into oils, asphaltenes, preasphaltenes and solid residue using pentane, toluene and THF as extractive solvents. Three iron-oxide containing catalysts: red mud, an Fe2O3 aerosol and Cottrell ash (by-product of the aluminium industry); and three alumina supported catalysts: CMA, which is a conventional CoMo/Al2O3 catalyst, CZMA which in addition contains Zn as a second promoter, and CZMFA which has the alumina acidified with fluorine and also contains Zn, were compared. It has been reported that the addition of Zn and of F enhances the HDS, cracking, hydrocracking or hydrogenating activities of CoMo/Al2O3 catalysts in experiments with pure compounds. The objective of this study was to determine if the addition of Zn and of F has also a beneficial effect in the catalyst activities in coal liquefaction, and also to compare cheap iron containing catalysts with the more sophisticated and expensive alumina supported ones.

The results showed that 1) Catalysts effects depend on the operating conditions used, and that with tetralin, a strong H-donor solvent, they never are very pronounced. 2) The supported catalysts have higher activities in coal liquefaction than the iron ones, but there are no significant differences among the catalysts within each group. 3) Zn, which is a cheaper metal than Co, can substitute succesfully for half the amount of Co and retain the activity of the CoMo/Al2O3 catalyst in coal liquefaction. 4) The addition of F to the CoMo/Al2O3 catalyst does not show a benefecial effect     

CoMo/MgO催化剂的制备及其对二苯并噻吩的加氢脱硫性能

以MgO为载体,采用等体积浸渍法制备了MgO负载的CoMo硫化物催化剂(CoMo/MgO);作为比较,制备了γ-Al₂O₃负载的CoMo硫化物催化剂(CoMo/γ-Al₂O₃)。在反应条件:反应温度260℃、氢分压为3.0 MPa、氢气流量为50 mL/min、质量空速(WHSV)为19 h^-1的情况下,CoMo/MgO催化剂对DBT的转化率为88.3%,高于CoMo/γ-Al₂O₃催化剂的65.5%。经XRD、UV-vis、XPS分析:与CoMo/γ-Al₂O₃催化剂相比,CoMo/MgO催化剂上形成了更多的八面体钼物种,通过硫化,可以形成更多的CoMoS活性相。     

MgO对Co-Mo/Al_2O_3-MgO催化剂性能的影响

采用尿素螯合剂法制备了不同MgO含量的Co-Mo/Al2O3-MgO催化剂,采用N2吸附-脱附法、TPR、HRTEM等技术对催化剂进行了表征,在管式固定床反应器中以二苯并噻吩(DBT)的二甲苯溶液为模型化合物对催化剂的加氢脱硫活性进行了评价。实验结果表明,添加MgO可显著改善Co-Mo/Al2O3催化剂的结构和性能,Co-Mo/Al2O3-MgO催化剂呈现出多孔径中心的特点;随MgO添加量的增加,Co-Mo/Al2O3-MgO催化剂中的Co-O-Mo物相增多,硫化后易形成更多高活性Co-Mo-S物相。与Co-Mo/Al2O3和Co-Mo/Al2O3-TiO2催化剂相比,Co-Mo/Al2O3-MgO-0.8(载体中MgO的质量分数为0.8)催化剂在氢烃体积比为300时即呈现出很高的DBT脱除率(97.0%),具有低氢烃比下即可实现高加氢脱硫活性的优点。     

IRON COMPOUNDS AND C0-Mo/Al2O3 CATALYSTS: ACTIVITY IN DIRECT HYDROGENATION OF A SUBBITUMINOUS A COAL WITH AN H-DONOR SOLVENT

Abstract

The effectiveness of different catalysts were compared in coal liquefaction experiments using a 250 ml stirred autoclave, 10 g of a Spanish Subbituminous A coal, 1 hour reaction time, 17 MPa operating pressure, 400 rpm stirring speed, at 425 and 450 °C with 2/1 and 3/1 tetralin/coal ratio. The liquefaction products were fractionated into oils, asphaltenes, preasphaltenes and solid residue using pentane, toluene and THF as extractive solvents. Three iron-oxide containing catalysts: red mud, an Fe2O3 aerosol and Cottrell ash (by-product of the aluminium industry); and three alumina supported catalysts: CMA, which is a conventional CoMo/Al2O3 catalyst, CZMA which in addition contains Zn as a second promoter, and CZMFA which has the alumina acidified with fluorine and also contains Zn, were compared. It has been reported that the addition of Zn and of F enhances the HDS, cracking, hydrocracking or hydrogenating activities of CoMo/Al2O3 catalysts in experiments with pure compounds. The objective of this study was to determine if the addition of Zn and of F has also a beneficial effect in the catalyst activities in coal liquefaction, and also to compare cheap iron containing catalysts with the more sophisticated and expensive alumina supported ones.

The results showed that 1) Catalysts effects depend on the operating conditions used, and that with tetralin, a strong H-donor solvent, they never are very pronounced. 2) The supported catalysts have higher activities in coal liquefaction than the iron ones, but there are no significant differences among the catalysts within each group. 3) Zn, which is a cheaper metal than Co, can substitute succesfully for half the amount of Co and retain the activity of the CoMo/Al2O3 catalyst in coal liquefaction. 4) The addition of F to the CoMo/Al2O3 catalyst does not show a benefecial effect     

CoMo/MgO催化剂的制备及其对4,6-二甲基二苯并噻吩的加氢脱硫性能

以高比表面积的纳米氧化镁(MgO)为载体,分别以四硫代钼酸铵、钼酸铵为Mo源,采用浸渍法制备了MgO负载的催化剂CoMo/MgO-S和CoMo/MgO-O;并对硫化后的催化剂进行了N₂吸附-脱附、XPS、TEM等系列表征;以4,6-二甲基二苯并噻吩(4,6-DMDBT)为模型化合物,考察了CoMo/MgO-S和CoMo/MgO-O的加氢脱硫活性。结果表明：与CoMo/MgO-O催化剂相比,CoMo/MgO-S具有比表面积大、Mo物种的硫化程度高、活性相堆垛层数多等特点;以CoMo/MgO-S为催化剂,4,6-DMDBT的转化率为70.8%,分别高于CoMo/γ-Al₂O₃-O和CoMo/MgO-O催化剂的59.8%和52.3%;进一步消除传质的影响,得到CoMo/MgO-S催化剂的催化转化频率(TOF)为2.2 h^-1,优于CoMo/MgO-O催化剂。