SiO2掺杂对V-Mo/TiO2催化剂脱硝性能的影响

采用共沉淀法制备不同SiO₂掺杂量的TiO₂-SiO₂复合载体,采用浸渍法在这些复合载体上负载活性组分V₂O₅和MoO₃,制备不同SiO₂掺杂量的V-Mo/TiO₂-SiO₂催化剂 (VMTS)。运用XRD,SEM,BET,H₂-TPR等分析手段对催化剂的理化性能进行表征,结果表明：随着SiO₂掺杂量的增加,VMTS催化剂的XRD谱图中不仅出现了SiO₂衍射峰,而且出现了锐钛矿型TiO₂的衍射峰,表明活性组分V₂O₅和MoO₃含量相对较低,主要以非晶态或微晶态形式存在;掺杂SiO₂的催化剂H₂-TPR还原峰向低温方向移动,同时比表面积和孔体积增大,孔径减小;与其他催化剂相比,SiO₂与TiO₂的质量比为0.2∶1的催化剂VMTS-(0.2∶1)具有最佳的氧化还原能力。脱硝效率评价结果表明：VMTS-(0.2∶1)催化剂具有最佳的烟气脱硝效率,烟气中通入SO₂时,VMTS催化剂烟气脱硝效率下降幅度均低于未掺杂SiO₂的催化剂,VMTS-(0.2:1)催化剂烟气脱硝效率下降幅度最小,说明掺杂SiO₂有利于催化剂抗硫性能的提高。     

SiO2掺杂对V-Mo/TiO2催化剂脱硝性能的影响

采用共沉淀法制备不同SiO₂掺杂量的TiO₂-SiO₂复合载体，采用浸渍法在这些复合载体上负载活性组分V₂O₅和MoO₃，制备不同SiO₂掺杂量的V-Mo/TiO₂-SiO₂催化剂 (VMTS)。运用XRD,SEM,BET,H₂-TPR等分析手段对催化剂的理化性能进行表征，结果表明：随着SiO₂掺杂量的增加，VMTS催化剂的XRD谱图中不仅出现了SiO₂衍射峰，而且出现了锐钛矿型TiO₂的衍射峰，表明活性组分V₂O₅和MoO₃含量相对较低，主要以非晶态或微晶态形式存在；掺杂SiO₂的催化剂H₂-TPR还原峰向低温方向移动，同时比表面积和孔体积增大，孔径减小；与其他催化剂相比，SiO₂与TiO₂的质量比为0.2∶1的催化剂VMTS-(0.2∶1)具有最佳的氧化还原能力。脱硝效率评价结果表明：VMTS-(0.2∶1)催化剂具有最佳的烟气脱硝效率，烟气中通入SO₂时，VMTS催化剂烟气脱硝效率下降幅度均低于未掺杂SiO₂的催化剂，VMTS-(0.2:1)催化剂烟气脱硝效率下降幅度最小，说明掺杂SiO₂有利于催化剂抗硫性能的提高。     

Cu/HZSM-5催化剂低温NH3-SCR脱硝性能研究

采用浸渍法制备Cu（x）/HZSM-5系列催化剂并应用于低温NH₃选择性催化还原脱硝性能研究。在固定床微型反应器上进行了O₂存在条件下催化剂的NH₃选择性催化还原NO活性评价,并通过XRD（X射线衍射仪）,SEM（扫描电子显微镜）,NO-TPD（程序升温脱附）,O₂-TPD,TG-DSC-MS（热重-差示扫描量热法-质谱联用）等对催化剂性能进行表征。结果表明,催化剂的催化脱硝活性随着Cu负载量增加而逐渐增强,Cu负载量影响催化剂表面活性物种分布、氧化还原性能和吸附脱附性能,Cu以CuO的形式存在于催化剂表面或空隙中。Cu（6）/HZSM-5表现出较好的低温脱硝性能,与其拥有较好的氧化性能和NO吸附脱附性能等有关,159～378℃时NO的转化率接近100%。     

Ti掺杂对Ni/ZnO-TiO2吸附剂用于FCC轻汽油脱硫性能的影响

采用混捏法制备了不同Ti含量的ZnO-TiO₂载体,采用等体积浸渍法制备了NiO/ZnO-TiO₂汽油脱硫吸附剂前驱体,并采用X射线衍射(XRD)、压汞、NH₃程序升温脱附(NH₃-TPD)、H₂程序升温还原(H₂-TPR)和H₂程序升温脱附(H₂-TPD)等手段对其进行了表征。以催化裂化轻汽油为原料,于氢气氛围下对NiO/ZnO-TiO₂前驱体还原得到Ni/ZnO-TiO₂吸附剂,在固定床上考察了Ti掺杂对该吸附剂脱硫性能的影响。结果表明：Ti的掺杂提高了Ni/ZnO吸附剂中活性组分Ni的分散度,增加了Ni活性位点,增强了吸附剂中强酸酸性及酸强度,Ti掺杂的吸附剂脱硫性能显著提高;Ti的掺杂能够减少游离Ni,有效抑制烯烃饱和;吸附剂脱硫性能随着Ti掺杂量的增加呈现先增强后减弱的趋势,当Ti掺杂质量分数为5%时,吸附剂具有最优脱硫性能,能够将FCC轻汽油中硫质量分数由300 μg/g降低至5 μg/g以下,穿透硫容为6.711%(每克吸附剂吸附硫67.11 mg),烯烃质量分数增加0.6百分点,降低了汽油辛烷值损失。     

V2O5-MoO3/TiO2催化剂脱硝性能的研究

通过挤压成型法制备了一系列蜂窝状V₂O₅-MoO₃/TiO₂催化剂。研究了钒、钼负载量对催化剂脱硝活性的影响,测试了催化剂抗硫和抗碱金属钠中毒的性能。采用X射线衍射、N₂吸附-脱附、扫描电子显微镜等表征手段,对新鲜催化剂和钠中毒催化剂的物理和化学性质进行分析。结果表明：当钒负载量（w）为1.5％～2.5％时,催化剂的脱硝性能随钒负载量的增加而提高;当钒负载量（w）为1.5%、钼负载量（w）为4.0％时,催化剂的脱硝性能最优;SO₂对V₂O₅-MoO₃/TiO₂催化剂的中毒作用是可逆的,可以通过热处理来恢复;当Na₂O负载量（w）为2.0％时,催化剂失活严重,这主要是由于钠盐在催化剂表面附聚而形成不规则的白色颗粒,覆盖了活性位点,导致催化剂的表面积减小,氧化还原性变差。同时,Na掺杂会影响催化剂中元素的化学状态和表面组成,降低V⁵⁺与化学吸附的O_α的比例。     

分子筛镍基催化剂对1,4-丁炔二醇加氢制1,4-丁烯二醇催化性能研究

采用等体积浸渍法将Ni分别负载在USY,ZSM-5,SBA-15,Al₂O₃载体上制备Ni质量分数为17%的负载型镍基催化剂,分别用X射线衍射、N₂吸附-脱附、H₂程序升温还原以及NH3程序升温脱附对催化剂进行表征,并考察其在氢气压力为4 MPa、反应温度为120 ℃、不同反应时间下催化1,4-丁炔二醇（BYD）加氢制1,4-丁烯二醇(BED)的加氢性能。结果表明：在基于不同载体的催化剂作用下BYD转化率存在较大差异;其他条件相同时,Ni/SBA-15作用下反应2.5 h时的BYD转化率达到97.8%,BED选择性为98.7%,且2-羟基四氢呋喃（HTHF）的选择性最低,这与Ni/SBA-15具有较大的比表面积和平均孔径、良好的活性金属组分镍分散性和较弱的酸性有关。     

正己烷异构化Pt/SZA催化剂构效关系研究

采用等体积浸渍法制备了Pt/SZA固体超强酸催化剂,采用X射线衍射、N₂吸附-脱附、NH₃程序升温脱附等方法对催化剂进行了表征,并考察了超强酸高温处理和载硫量对其催化正己烷异构化性能的影响。结果表明：适宜的超强酸焙烧温度为550 ℃,催化剂载硫量（w）为3.15%,此时制备的Pt/SZA催化剂抑制了单斜晶相ZrO₂的生成,具有适宜的孔结构性质和较多的酸中心;在相同反应条件下,催化剂催化正己烷异构化活性最高,且具有优良的异构产物分布。     

LaCo0.7B0.3O3催化剂CO-SCR脱硝性能研究

采用柠檬酸络合燃烧法制备了LaCo_0.7B_0.3O₃(B=Cr, Mn, Fe)催化剂，通过X射线衍射(XRD)、傅里叶变换红外光谱(FT-IR)、扫描电镜(SEM)、氢气程序升温还原(H₂-TPR)和一氧化氮程序升温脱附(NO-TPD)等表征方法对LaCo_0.7B_0.3O₃催化剂的理化性质进行了表征，并在常压固定床微型反应器中评价了LaCo_0.7B_0.3O₃催化剂的CO选择性催化还原(COSCR)脱硝活性。结果表明，过渡金属(Cr、Mn或Fe)部分取代了LaCoO₃催化剂中的Co,Cr、Mn或Fe进入LaCoO₃骨架中，LaCo_0.7B_0.3O₃催化剂具有钙钛矿结构，无杂相生成，但引起了晶格畸变。过渡金属部分取代Co会影响催化剂的粒度、分散性、氧化还原性能和N...     

Y分子筛与无定形硅铝的比例对柴油加氢裂化催化剂性能的影响

以不同比例改性Y分子筛与无定形硅铝为酸性组分制备载体,采用等体积浸渍法制备Ni-Mo型加氢裂化催化剂;通过N₂吸附-脱附、NH₃-程序升温脱附、吡啶吸附红外光谱、X射线衍射、H₂-程序升温还原等方法对催化剂进行分析表征,并以混合柴油为原料,在固定床反应器上考察制备的催化剂的加氢裂化性能。结果表明：随着改性Y分子筛含量的增加,催化剂强酸范围内的B酸酸量和B酸酸量/L酸酸量比值（简称B/L）均先增加后降低,Y分子筛含量过高时,活性组分出现堆积。改性Y分子筛与无定形硅铝的质量比为1.0时,催化剂的比表面积和孔径适中,活性组分分散较优,强酸范围内的B酸酸量最高,B/L最大;应用于柴油加氢裂化,催化剂的活性最高,柴油中芳烃的转化率最高,大于250 ℃馏分转化率最高,尾油收率最低,相关指数（BMCI）最低;重石脑油和喷气燃料收率之和最高,重石脑油芳烃潜含量最高。     

过渡金属对Au-Pd/TiO_2-Al_2O_3催化剂加氢脱硫性能的影响

研究了掺杂过渡金属Ru,Ni,Co对Au-Pd/TiO2-Al2O3催化剂催化噻吩加氢脱硫活性的影响,并采用X射线衍射、电感耦合等离子发射光谱、程序升温还原和程序升温脱附等方法对TiO2-Al2O3复合载体、Au-Pd/TiO2-Al2O3和Au-Pd-TM/TiO2-Al2O3(TM表示过渡金属)催化剂进行了表征。实验结果表明,掺杂过渡金属未改变Au-Pd/TiO2-Al2O3催化剂的结构;掺杂Ru或Ni增强了Au-Pd/TiO2-Al2O3催化剂的活性组分与TiO2-Al2O3复合载体的相互作用,降低了反应活化能,提高了催化剂活性组分的分散度和活性比表面积,改善了Au-Pd/TiO2-Al2O催化剂的吸附性能,从而提高了Au-Pd/TiO2-Al2O3催化剂催化噻吩加氢脱硫的活性;而掺杂Co的效果则与之相反。     

载体对Mn-Ce催化剂低温SCR脱硝性能的影响

使用3种组成不同的钛白粉作为载体,采用浸渍法制备Mn-Ce/TiO2,Mn-Ce/TiO2-SiO2,Mn-Ce/TiO2-WO3催化剂,采用XRD,BET,SEM等方法对催化剂的微观结构及形貌进行表征,探索SiO2、WO3的掺加对催化剂脱硝活性和抗硫性能的影响。结果表明：掺加SiO2、WO3有助于增大载体的比表面积及催化剂表面活性酸中心数量,催化剂的脱硝活性和抗硫性能得到提高;在空速为10 000 h-1、反应温度为100 ℃的条件下,Mn-Ce/TiO2催化剂上NO去除率仅为30%,Mn-Ce/TiO2-SiO2和Mn-Ce/TiO2-WO3催化剂上NO去除率分别为45% 和50%;当反应气中含有150 μL/L的SO2时,在反应温度为150 ℃、反应时间为270 min的条件下,与不含SO2时相比,Mn-Ce/TiO2催化剂上NO去除率从80%降低至40%,Mn-Ce/TiO2-SiO2和Mn-Ce/TiO2-WO3催化剂上NO去除率从84%降至55%和70%。     

Oxidehydrogenation of Ethylbenzene Over Supported TiO2 Catalysts

Six different metals as active components of catalyst for dehydrogenation of ethylbenzene were supported over TiO₂ using isovolumetric impregnation method. In the bench scale experiment at 623 K an effective catalyst V₁/TiO₂ was found, 18.8% ethylbenzene with 100% styrene selectivity acquired. Various characterization techniques, physisorption, SEM/EDX, XRD, TGA, and particle size analyzer, were employed to analyze the features of catalysts. Results showed that lower calcined temperatures helped to increase the selectivity of styrene when V₁/TiO₂ was calcined at 523 K while the reaction temperature was 623 K. The pore distribution was concentrated and the growth of active components crystalline grains in V₁/TiO₂ catalyst could be effectively controlled when it was calcined in lower temperature during preparation. The agglomeration of V on the surface of V₁/TiO₂ catalyst during reaction leads to the decrease of ethylbenzene conversion.     

Pt/TiO2催化剂微乳液法制备条件对邻氯硝基苯选择性加氢性能的影响

采用十六烷基三甲基溴化铵/正丁醇/环己烷/H2PtCl6溶液的微乳体系,以N2H4?H2O为还原剂、TiO2为载体制备Pt/TiO2催化剂。以邻氯硝基苯选择性加氢反应为探针反应,考察微乳液组成及TiO2晶型对催化剂选择性加氢活性的影响。结果表明：当微乳体系中mCTAB:m正丁醇＝3:7、(mCTAB+m正丁醇):m环己烷＝3:7、H2PtCl6溶液用量占体系质量的3.6%时,制备的Pt/TiO2催化剂的邻氯硝基苯选择性加氢活性最高;锐钛矿型TiO2有助于提高催化剂的活性。     

A STUDY ON THE EFFECT OF PREPARATION PARAMETERS ON THE CATALYTIC PERFORMANCE AND ACTIVE COMPONENTS OF A NEW TYPE HYDRODESULFURIZATION CATALYST

The effects of the impregnating conditions on the contents of the active components of a new type hydrodesulfurization (HDS) catalyst have been studied by ICP technique in this paper. Meanwhile, the effects of the activation temperature, the activation time and the calcining temperature on the catalytic properties of the CoMo/(TiO₂ + Al₂O₃) catalyst have also been studied. The results show that at the given hygroscopicity of the support, the contents of the Co and the Mo, both of which are the active components of the catalyst, change linearly with the changes of the concentrations of the solvents in the impregnant. When the catalyst is impregnated at 40°C for 2 h, the contents of the active components reach the maximum values. The calcining temperature sharply affects the dispersed state of the active components on the surface of the support. When calcined at 500°C for 2 h, this HDS catalyst obtains the best catalytic activity. Even when the catalyst has been calcined at 600°C for 3 h, its activity is still good, which indicates that the heat resistance of this new type catalyst is satisfactory.     

PREPARATION OF NEW TYPE CATALYST WITH GOOD PROPERTIES FOR HYDRODESULFURIZATION

The CoMo/TiA catalyst for hydrodesulfurization (HDS) and its composite support TiA with industrial scale had been produced through the certain process and the studied range of ratio of TiO₂/(TiO₂ + Al₂O₃) was enlarged. The good properties of the support TiA were attributed to its special pore structure. When the ratio of TiA/(TiA + Al₂O₃) was 0.80, the specific surface area of the support and its pore volume reached their maximum respectively. The range of atom ratio of Co/(Co + Mo) of the catalyst CoMo/TiA from 0.25-0.31 proved best, during which activity of the catalyst reached the maximum. The disperse state of TiO₂ on the surface of TiA and effect of the promoter Co content on the surface structure of the catalyst had been studied by XRD, LRS and XPS. The analytic results showed that 0.47 g TiO₂/g γ-Al₂O₃ was the schwellenwert for the coverage of TiO₂ on the surface of TiA. Beyond this, TiO₂ lies on the surface of TiA with a single layer; otherwise, it existed in the form of TiO₂ crystal phase (anatase phase). When adding a few promoters Co into the catalyst, the dispersity of MoO₃ on the surface of the support TiA increased remarkably and activity of this catalyst was also improved.     

Hydrotreating of Maya Crude Oil: I. Effect of Support Composition and Its Pore-diameter on Asphaltene Conversion

A systematic study for a concept governing support effect in heavy oil hydrotreating (HDT) catalysts is performed. Different Al₂O₃ and its mixed oxides supports were prepared and CoMo supported catalysts were tested for Maya heavy crude oil hydrotreating. Fresh and spent catalysts are characterized with N₂ adsorption-desorption, element analysis, and scanning electron microscopy-energy dispersion analysis by x-ray (SEM-EDAX), which confirms that coke and metals deposition on the surface of catalyst is most probably near the pore mouth. It is also demonstrated from these results that asphaltene conversion depends on the pore diameter of the catalyst, while other hydrotreating conversions (hydrodesulfurization (HDS), hydrodenitogenation (HDN), and in some extent hydrodemetallization (HDM)) are more likely affected by the nature of active metal distribution. The evaluation of alumina mixed oxide (TiO₂, ZrO₂, B₂O₃, and MgO) supported catalysts indicates that supports with basic nature have better stability than the acid ones.     

COMPARISON BETWEEN THE PERFORMANCE OF CONVENTIONAL AND HIGH-METAL Co-Mo AND Ni-Mo CATALYSTS IN DEEP DESULFURIZATION OF KUWAIT ATMOSPHERIC GAS OIL

Due to environmental constraints, sulfur content of diesel fuel has been restricted to very low levels (500 ppm maximum) in many countries. As a result, a greater emphasis has been placed in recent years on the development of catalysts and processes for deep desulfurization of diesel blending streams to produce low sulfur diesel fuel. In the present work we have compared the performance of a conventional Co-Mo catalyst with that of high metal loading Co-Mo and Ni-Mo catalysts in deep desulfurization of Kuwait atmospheric gas oil. The tests were carried out in a fixed bed reactor unit using 75 ml of catalyst under the conditions: P=32 bar; LHSV = 4h^-1; H₂/oil ratio = 100 ml/ml; temperature range = 330 - 390°C. HDS activity of the high molybdenum Co-Mo catalyst was superior to that of the conventional Co-Mo hydrotreating catalyst. High metal loading Co-Mo/Al₂O₃ catalyst also showed a substantially higher HDS activity than the Ni-Mo/Al₂O₃ catalyst containing a similar high metal loading. The unreacted sulfur compounds remaining in the product after high severity hydrotreating were identified as dibenzothiophenes with alkyl substituents next to the sulfur atom. The desulfiirization of such low reactive alkyl dibenzothiophenes was found to occur at a substantially lower temperature over the high metal loading Co-Mo catalyst compared with the conventional Co-Mo catalyst. The results have been explained on the basis of the stacking and dispersion of MoS₂ slabs as well as in terms of the nature of the sulfur vacancies in the MoS₂ layers in these catalyst systems.     

焙烧温度对MnOx催化还原NO性能的影响

以金属有机骨架为牺牲模板制备了一系列MnO_x催化剂,考察了焙烧温度对催化剂脱硝性能的影响,并利用多种手段对催化剂的表面结构和物化性质进行分析表征。结果表明：随着焙烧温度的升高,Mn₃O₄的结晶度变好,但不利于活性组分的分散;MnO_x催化剂的比表面积和孔体积变小,孔径增大;MnO_x催化剂具有的弱酸性位点减少,氧化还原性能变差,进而催化剂的低温脱硝活性变差。活性评价结果表明,300 ℃焙烧的MnO_x催化剂具有最佳的低温活性,在体积空速为20 000 h^-1的条件下,反应温度为120～200 ℃时,NO转化率达90%以上。