生物质甘油经气化制甲烷Ni-Ce/Al2O3催化剂研究

采用浸渍法制备了助剂Ce掺杂的Ni/Al_2O_3催化剂,用于甘油重整气甲烷化反应,分别采用BET、XRD、H_2-TPR、CO_2-TPD等手段对催化剂进行了表征,并考察了Ce掺杂量、甲烷化温度、在线运行时间对Ce掺杂Ni/Al_2O_3催化甲烷化性能的影响。结果表明,掺杂的Ce会优先占据Ni/Al_2O_3催化剂的微孔,抑制活性组分Ni与载体Al_2O_3相互作用而生成尖晶石NiAl_2O_4,促进表面高度分散的活性Ni的生成,其催化还原性、甲烷化性能得以提高。3%(w)Ce掺杂的Ni/Al_2O_3在甘油重整气甲烷化反应中最佳温度范围为275~300℃,CO和CO_2转化率分别可达99%和75%以上,每千克甘油经水蒸气重整、甲烷化反应后生成的甲烷量达到570L以上。     

反应器材质对Ni-Co双金属催化剂上沼气重整制氢性能与积炭的影响

采用传统湿式浸渍法制备了La_2O_3掺杂的商业γ-Al_2O_3负载的沼气重整催化剂Ni-Co/La_2O_3-γ-Al_2O_3。采用CH_4/CO_2体积比为1的混合气体模拟沼气,考察了反应器材质对沼气重整制氢催化剂性能的影响,进一步结合XRD、BET、TEM、TG-DSC等表征,探究了其对催化剂结构及反应器内壁积炭的影响。结果表明,反应器材质能影响催化剂的表面特性、稳定性以及反应器内壁的积炭情况;在反应310 h后不锈钢反应器内催化剂表面积炭量为6.09%,但反应510 h后石英管反应器内催化剂表面积炭量仅为1.91%;且不锈钢反应器内壁积炭严重,石英管反应器内壁无明显积炭;不锈钢反应器内壁的积炭主要是丝状碳纳米管和石墨碳。     

CH_4-CO_2重整炭基催化剂的制备及应用研究

以神华集团煤直接液化残渣为原料,采用KOH活化法,经炭化、活化一体反应制得炭基催化剂。利用TG、SEM、BET、XRD等表征分析,确定了炭基催化剂的制备条件,探究了炭基催化剂的失重行为、碱炭比、比表面积及孔径的大小等因素对CH_4-CO_2重整制合成气反应催化活性的影响。结果表明在经过KNO_3预氧化、碱炭质量比为3的KOH活化条件下制备的炭基催化剂,收率为43.3%、比表面积达到1632m~2/g,该催化剂在CH_4-CO_2重整反应中具有良好的催化效果,可使CH_4和CO_2的转化率均达90%以上。     

Ni/La-BaTiO3催化剂的低温CH4/CO2重整性能研究

镧液相掺杂合成了不同镧含量的La-BaTiO3载体,再通过浸渍负载活性组分制备出Ni/La-BaTiO3催化剂。通过CH4/CO2连续重整制合成气反应,考察常压下、700℃和750℃温度的Ni/La-BaTiO3催化剂稳定性和积炭性能;采用CO2脉冲反应评价了700℃低温重整条件下各Ni/La-BaTiO3催化剂上一氧化碳的歧化反应程度。结果表明,一氧化碳的歧化反应程度对催化剂低温CH4/CO2重整的稳定性和积炭性能影响显著,Ni/1.05%La-BaTiO3是最佳的低温CH4/CO2重整催化剂。     

重整催化剂Ni2P/Al2O3-SAPO-11积炭失活规律研究

Ni2P/Al2O3 SAPO 11催化剂用于催化重整过程易于积炭失活。通过与Ni2P/Al2O3、Pt/Al2O3 SAPO 11及Ni/Al2O3 SAPO 11催化剂表面积炭行为对比,研究了该催化剂表面的积炭规律。以甲基环戊烷为积炭前驱物,在不同温度下进行加速积炭实验,采用热重 差示热分析表征催化剂表面积炭位置,并以环己烷、正庚烷为模型化合物对积炭前后催化剂进行脱氢 异构反应催化性能评价。结果表明,由于P原子的作用,Ni2P/Al2O3 SAPO 11重整催化剂具备一定的抗积炭性能,其积炭形成速率介于Pt/Al2O3 SAPO 11和Ni/Al2O3 SAPO 11催化剂之间;积炭在Ni2P/Al2O3 SAPO 11重整催化剂金属活性中心上形成后,逐步迁移到酸性载体上形成聚合度更高的积炭,并且酸性载体上的积炭是催化剂失活的主导因素。     

NiO/Al_2O_3上添加La_2O_3对甲烷部分氧化制合成气的影响

在固定床流动反应装置上研究了NiO/Al_2O_3催化剂及其添加La_2O_3对甲烷部分氧化制合成气的影响.主要考察了催化剂的引发温度、催化活性和积炭问题.并利用TPR和XRD技术对这些性能进行了关联.结果表明,焙烧温度升高,NiO与Al_20_3之间作用增强,使引发温度升高.添加La_20_3后削弱了Ni0与Al_2O_3的作用,形成了新相LaNiO_3,有利于引发反应.在NiO/Al_2O_3上添加2%(mass)La_2O_3则具有最佳的催化活性,并在一定程度上增加了催化剂的抗积炭能力.     

煤层气转化制合成气的催化剂研究

煤层气转化制合成气工艺的生产成本低、能耗小,对减轻全球性温室效应具有一定的作用,是煤层气利用的较好方案,但该反应存在催化剂积炭严重易失活等问题。为此,采用Ni/MgO—Al2O3催化剂,在常压固定床反应器上进行了CO2重整CH4制合成气反应的研究,系统地考察了载体制备方法、MgO含量、焙烧方式等因素对催化剂性质的影响,并采用N2物理吸附和XRD检测手段对催化剂进行了表征。结果表明,采用共沉淀方法制备催化剂载体,当MgO含量为4%,在550℃流动空气环境里焙烧4h后所得到的催化剂10%Ni/4%MgO—Al2O3用于煤层气转化制合成气的反应,CH4和CO2的转化率分别可达到82%和92%,且反应6h内转化率没有降低,催化剂未发生积炭现象,其催化活性和稳定性都较好。     

Ni-CaO-La_2O_3催化剂在乙醇水蒸气重整制氢中的应用

采用溶胶-凝胶法制备了Ni-CaO-La_2O_3催化剂,在固定床反应器中,以乙醇、水为原料考察了La和Ca对催化剂活性的影响,采用BET,H_2-TPR,XRD等方法对催化剂结构进行了表征。实验结果表明,同时加入La和Ca的20Ni-CaO-10La_2O_3催化剂的活性明显好于20Ni-CaO,20Ni-La_2O_3催化剂。20Ni-CaO-10La_2O_3催化剂在450℃左右能使乙醇完全转化,H_2选择性达94.7%,500℃时H_2选择性达100%;在550℃连续反应123 h,乙醇转化率还能保持94.8%以上。表征结果显示,加入La促进了活性组分Ni与碱金属Ca在催化剂中的均匀分散,且催化剂中Ni的粒径较小。     

负载型复合载体及其镍基催化剂的性能

采用溶胶-凝胶法制备了负载型ZrO_2/Al_2O_3和ZrO_2/Al_2O_3-SiO_2复合载体,研究了不同复合载体对Ni基催化剂CO_2重整甲烷反应和性能的影响,并用XRD、IR、TPR、TPD和BET等方法对复合载体及催化剂进行了表征。结果表明,ZrO_2负载在基载体后比表面积、碱性、活性组分Ni的分散度和Ni与ZrO_2的相互作用增大。NiO在复合载体表面的分散容量与ZrO_2的负载量有关,ZrO_2的负载量为37．5%时NiO的分散容量达最高值(24．0%)。与Ni/ZrO_2相比,Ni/ZrO_2/Al_2O_3-SiO_2和Ni/ZrO_2/Al_2O_3催化剂对CO_2的吸附能力增大,CO_2吸附量增加,酸强度降低,CO_2重整CH_4反应活性提高,其中以Ni/ZrO_2/Al_2O_3催化剂的活性最好。     

MoO3-WO3/TiO2-SiO2催化剂对正庚烷异构化的催化性能

 采用溶胶-凝胶法制备了TiO₂-SiO₂复合氧化物载体,浸渍法制备了MoO₃-WO₃/TiO₂-SiO₂催化剂,通过XRD、BET表征了催化剂的物化性质,并在连续流动固定床反应器上考察了MoO₃-WO₃/TiO₂-SiO₂催化正庚烷临氢异构化反应性能,讨论了催化剂制备条件和反应条件对其正庚烷异构化催化性能的影响。结果表明,当 w(MoO₃)=5%、w(WO₃)=15%、w(TiO₂)=80%、w(SiO₂)=20%、焙烧温度773 K、还原温度723 K、反应温度553 K、还原时间6 h 时,MoO₃-WO₃/TiO₂-SiO₂催化剂对正庚烷异构化反应表现出最高催化活性,此时正庚烷转化率可达23.12%, 异庚烷选择性可达77.32%。     

Ni/ZSM-5 CATALYST FOR CH4 REFORMING WITH CO2

Abstract

For good physical and chemical proprieties of ZSM-5 and its selectivity to higher hydrocarbons it is selected as support carrier. In this paper CH₄ reforming with CO₂ to synthesize heavier hydrocarbons over Ni/ZSM-5 catalyst is investigated. The reforming reaction is operated at 1073K under the ambient pressure in a fixed-bed tabular reactor. As promoter rare earth oxides, La₂O₃, CeO₂, Pr₆O₁₁ and Nd₂O₃ are separately added to Ni/ZSM-5 and Ni-La/ZSM-5(NZL), Ni-Ce/ZSM-5(NZC), Ni-Pr/ZSM-5(NZP) and Ni-Nd/ZSM-5(NZN) are formed accordingly. For convenience, they are recorded as Ni-RE/ZSM-5. When these catalysts are used in the reforming reaction the yield of heavier hydrocarbons is obviously increased. The structure of Ni-RE/ZSM-5 catalysts before and after reaction is systematically characterized by XRD, XPS, TEM, SEM, ICP and FTIR. After 10 hours reaction there are more carbon deposit on Ni-RE/ZSM-5 catalyst than Ni/ZSM-5, but their structure are not destroyed and carbon deposit is easy gasified.     

超声波辐照浸渍法制备MnO2/γ-A12O3催化剂及其柴油催化氧化脱硫性能

 分别采用超声波辐照浸渍法和普通浸渍法制备了MnO₂/γ-Al₂O₃催化剂,运用电感耦合等离子体原子发射光谱（ICP-AES）和X射线衍射（XRD）对催化剂进行表征,在空气-异丁醛-MnO₂/γ-Al₂O₃体系中评价其对加氢柴油的氧化脱硫催化性能,并考察了反应温度、异丁醛用量、空气流量、溶剂类型和剂/油体积比对柴油氧化脱硫反应的影响。结果表明,超声波辐照浸渍法制备的MnO₂/γ-Al₂O₃催化剂对柴油氧化脱硫的催化性能明显优于普通浸渍法制备的催化剂。最适宜的催化柴油氧化脱硫反应的条件为：乙腈为溶剂、加氢柴油30 mL、温度35℃、异丁醛20 mmol、空气流量0.06 L/min、超声波辐照浸渍法制备的MnO₂/γ-Al₂O₃催化剂0.08 g、剂/油体积比1/6和催化氧化时间10 min。在此条件下可将柴油硫质量分数从542μg/g 降至31μg/g,柴油脱硫率和回收率分别为94.3%和93.3%。     

复合SiO2-WO3催化剂的制备、表征及氧化脱除苯并噻吩性能

 采用溶胶-凝胶法制备了SiO₂-WO₃催化剂,并采用XRD、FT-IR、BET、TG-DTA等方法对催化剂进行表征。以苯并噻吩(BT)为模型化合物,H₂O₂为氧化剂,考察了催化剂的活性元素、制备方法、n(W)/n(Si)和焙烧温度对其催化氧化脱硫活性的影响。结果表明,W的引入降低了SiO₂的比表面积,SiO₂-WO₃催化剂中W的主物相为WO₃。在以W为活性组元,且n(W)/n(Si)为0.1时,500℃焙烧得到的SiO₂-0.1WO₃催化剂具有最好的催化脱硫活性。在模拟油20 mL、催化剂SiO₂-0.1WO₃用量0.04 g、n(H₂O₂)/n(S)为15.9、乙腈/模拟油体积比0.3、65℃反应60 min的条件下,苯并噻吩模拟油脱硫率可达99.3%。     

孔径双峰分布γ-Al2O3负载NiMoP催化剂的制备及对蜡油加氢催化性能

在氢氧化铝干胶挤条成型时,调节纳米炭黑的加入量和水/粉质量比,制备了孔径呈双峰分布、具有较大孔容和比表面积的γ-Al2O3载体。当炭黑加入质量分数为13%、水/粉质量比1.15时,制备的孔径呈双峰分布的γ-Al2O3载体的孔容为0.80mL/g、比表面积为309m2/g,4～10nm和10～15nm孔径分别占总孔容50.8%和35.1%(体积分数),采用该载体制备的NiMoP/γ-Al2O3催化剂的孔径呈明显的双峰分布。在反应温度370℃、氢分压10MPa、氢/油体积比700、体积空速1.5h-1的条件下,制备的NiMoP/γ-Al2O3催化剂可使减压和焦化混合蜡油的硫质量分数由25600μg/g降至2070μg/g,脱硫率为91.9%,而参比催化剂仅可使减压和焦化混合蜡油硫质量分数降至3450μg/g,脱硫率为86.5%。     

Effects of Impregnation Solvents on Catalytic Performance of Co-Ru-ZrO2/γ-Al2O3 Catalyst for Fischer-Tropsch Synthesis

Abstract

Used ZrO₂ modified γ-Al₂O₃ as support, Co-Ru catalysts were prepared by incipient impregnation method. The effects of impregnation solvents on the performances of catalysts were examined. The catalyst was prepared with ethanol solution and high Co dispersion was obtained, exhibiting highest activity of CO hydrogenation, very low methane selectivity, and high heavy hydrocarbon C₅ ⁺ selectivity. The catalysts were prepared with aqueous solution and methanol solution, and the reaction behaviors were similar. The solvent isopropanol caused the lowest catalytic activity and highest methane selectivity. Increasing the reaction temperature enhanced the CO hydrogenation rate, and the CO conversion slightly increased the CO₂ selectivity and favored the formation methane and light hydrocarbons, while the chain growth probability decreased. For the catalyst prepared with ethanol, the CO conversion, the CH₄ selectivity, and the C₅ ⁺ selectivity were 94.16%, 5.65%, and 88.2%, respectively, and the chain growth probability was 0.87 at 493 K, 1.5 MPa, 800 h^?1, and n(H₂):n(CO) = 2.0 in feed.     

Influence of catalyst support structure on ethene/decene metathesis and coke formation over WO3/SiO2 catalyst

8wt%WO3/SiO2 metathesis (disproportionation) catalysts with different pore structures were prepared by the incipient-wetness-impregnation method. The as-synthesized catalysts were characterized by N2 adsorption-desorption, scanning electron microscopy (SEM), X-ray diffraction (XRD), UV-visible diffuse reflectance spectroscopy (DRS) and scanning transmission electron microscopy-high-angle annular dark field (STEM HAADF). The results of STEM HAADF showed that WO3 species were not uniformly distributed on the SiO2 support. The experimental results of 8wt%WO3/SiO2 performance in ethene/decene metathesis revealed that the catalytic effect of 8wt%WO3/SiO2 catalyst and coke formation over it were closely related to the support pore structure: The 8wt%WO3/SiO2 catalyst with a more complicated pore structure showed better catalytic performance but the coke deposition rate was also faster.     

Hydrogen production by catalytic methane decomposition over Ni,Co, and Ni-Co/Al2O3 catalyst

Hydrogen is a chief source of energy. Catalytic decomposition produces hydrogen and carbon. In this work, x%M/Al₂O₃ (where M is Ni, Co and combined Ni-Co, and x is 10%, 15%, and 30%) has been successfully employed as a catalyst. The effect of activation temperature and active metal type and loading on catalyst perfomance was investigated. The catalysts were characterized with BET, XRD, TPO, TPR, TEM, XPS, and Raman. The results displayed that the 30%Co/Al₂O₃ catalyst activated at 500°C provided the greatest catalytic performance toward methane conversion. 30%Co/Al₂O₃ catalyst activated at 500°C formed amorphous carbon.     

Kinetics of Carbon Dioxide Reforming of Natural Gas Using Different Catalysts

Abstract

The Kinetics of CO₂ reforming of natural gas to produce synthesis gas (CO + H₂) has been investigated using 2 g of 0.5% wt of each of the catalysts; rhodium, ruthenium and iridium supported on γ-alumina. The experiments were carried out in a tubular reactor at three temperature levels namely 600, 700, 800°C and four gas weight hourly space velocities; 18000, 36000, 45000, and 60000 ml g^?1 h^?1. The reaction was found to obey first-order kinetics for the depletion of both of the reacting components; CH₄ and CO₂ on all the investigated catalysts. At the same temperature, CO₂ had a higher reaction rate constant, k', as compared to CH₄ for all the catalysts. This was more pronounced for Rh/γ-alumina catalyst, which occupied the highest reaction rates. Activation Energies were calculated from the Arrhenius relation.     

Analysis for surface coke deposition in used Mo-Co/γ-Al2O3 catalyst for diesel hydrodesulfurization

The coked Mo-Co/γ-Al₂O₃ catalysts were Soxhlet extracted with the solvent of tetrahydrofuran. Experimental techniques like FT-IR, GC-MS, XPS, H₂-TPR, BET, etc. were applied for the characterization of coke and catalysts to make a comparison of their physical properties. The results showed that the active components of the catalyst were slightly less after the reaction. The specific surface area and the pore volume had recovered to some degree. These results indicated that the main cause of deactivation of Mo-Co/γ-Al₂O₃ catalysts is carbon deposit. The principal components of the soluble carbon deposit on Mo-Co/γ-Al₂O₃ catalysts were alkyl aromatics with 1–4 rings and C₁₉–C₂₉ long-chain alkane compounds.     

二氧化碳甲烷自热重整计算分析与中试

运用Gibbs自由能最小化方法和耦合详细反应动力学的计算流体力学(CFD)方法对CO_2-CH_4自热重整进行了相关的计算分析。结合自主研发的反应器和催化剂,在山西省潞安集团煤制油低碳循环经济园区进行了原料气处理量10 000m~3/h、运行压力2MPa、新型镍基催化剂装填量约5t的中试实验,获得合成气中甲烷摩尔分数小于1%、n(H_2)/n(CO)=1.1、有效气摩尔分数为60.7%的合成气。其中,CO_2-CH_4自热重整反应器设计主要尺寸为:内径1.6m,燃烧高度3.0m,催化剂装填高度2.8m,反应器总体高度约13.8m。