铈对Ru/γ-Al2O3变换催化剂的改性研究

采用浸渍法制备了一系列钌基催化剂,以水煤气变换为探针反应,采用XRD、TPR和TPD等手段研究了铈对Ru/γ-Al2O3催化剂的改性机制.结果表明,铈的加入显著地提高了Ru/γ-Al2O3催化剂的变换反应活性,增加了Ru/γ-Al2O3催化剂的活性中心数,降低了催化剂的还原温度,增强了催化剂对H2O的吸附和活化作用.     

稀土铁基无硫无铬型CO高温变换催化剂的研制

本文以铁和硝酸为主要原料 ,以稀土 (Ce O2 )为主要助剂 ,开发适合大型合成氨厂使用的稀土铁基无硫无铬型 CO高温变换催化剂 ,探讨了稀土 (Ce O2 )的加入量及制备过程中热煮方式、焙烧温度等对催化剂性能的影响。     

稀土和钼对铁系中温变换催化剂反应性能及表面性质的影响

以稀土和钼为助剂用浸渍法和混碾法制备出一系列无铬铁系催化剂，同时运用ＸＲＤ、ＴＰＲ和ＴＰＤ对催化剂的表面性质和ＣｅＯ２、ＭｏＯ３的作用进行了研究。实验结果表明，ＣｅＯ２、ＭｏＯ３能较大幅度地增加铁系催化剂的活性。ＣｅＯ２与ＦｅＯ３－ＭｏＯ３催化剂之间发生了相互作用，ＭｏＯ３能改善催化剂的氧化步骤，水的配位吸附是中温变换反应的低温活性中心，解离吸附是中变反应的高温活性中心。     

水煤气反应对浮氏体还原影响的实验研究

在900℃和1 000℃时,气体成分为(CO H2)/(CO CO2 H2)=0.85,H2/(CO H2)=0.3和(CO H2)/(CO CO2 H2)=0.75,H2/(CO H2)=0.3的条件下做了浮氏体还原实验.得出在温度高于810℃时,水煤气反应影响浮氏体还原,混合气体中CO2≥25%时表现明显,混合气体中CO2≤15%时影响较小.     

Cu-Zn催化剂的CO水汽变换反应特性

通过考察不同条件下烧结对Cu-Zn和Fe-Cr催化剂变换反应性能的影响,并结合催化剂的化学吸附表征手段,探讨了用Cu-Zn系催化剂替代Fe-Cr系催化剂作为高变催化剂的可行性.活性评价结果表明,从初期活性来看,Cu-Zn系催化剂不仅在低变温度,而且在高变温度下也优于Fe-Cr系催化剂;从催化剂的烧结特性来看,Cu-Zn系催化剂虽然在450℃的高温烧结条件下于初期阶段烧结明显,但500h之后逐渐趋于稳定,稳定后的活性仍优于Fe-Cr系催化剂.活性评价结果与CO化学吸附量测试结果相吻合.据此提出了不使用Fe-Cr系催化剂,在高、低温变换过程均使用Cu-Zn系催化剂的CO变换工艺,可将入口体积分数10%的CO去除到1%以下.     

稀土钼系杂多化合物对苯酚过氧化氢羟化反应催化活性的影响

本文研究了稀土钼系杂多化合物(NH4)12H10[Nd4Mo28O104(H2O)12]·22H2O对苯酚过氧化氢羟化反应的催化性能。探讨了反应温度、反应时间、反应介质、反应体系pH及n(phOH)／n(H2O2)(摩尔比)等对苯酚羟化反应催化活性的影响。实验结果表明以甲醇为溶剂,用合成的稀土钼系杂多化合物为催化剂添加适量的V2O5,体系pH为5．o,n(phOH)／n(H2O2)=11．5,反应温度为343K,反应5小时,苯酚的转化率达41.00％,对苯二酚的产率为37．85％。     

常压流化床水煤气炉的开发与应用

常压流化床水煤气炉是一种将流化燃烧和流化气化组合在同一气化炉内 ,间歇制取水煤气的专利气化技术。该炉具有煤种适应性广 ,通过改变加煤时间可调节煤气组分 ,以适应不同用途的需要 ,同时煤气生产过程中无焦油和酚类产生 ,利于达到环保要求 ,在生产煤气的同时副产水蒸汽 ,不需另设锅炉房 ,投资省 ,运行成本低 ,可用作我国中小城市的民用煤气和中小化肥厂的原料气     

钼系催化剂的生产技术（续1）

在前文的基础上［２］，再详述了六种重要钼系催化剂的生产工艺及其操作方法；其中对烃类水蒸气改性催化剂还专门介绍了其组分设计过程和具体方案等内容。简述了属国际首创的国产新型无铬一氧化碳高温变换制氨工业催化剂的特点、组成和应用价值     

YFeO_3/TiO_2-SnO_2声催化剂的制备及降解酸性红B的研究

采用溶胶凝胶法制备了YFeO3和超声分散法制备了YFeO3/TiO2-SnO2和YFeO3/TiO2复合物,通过酸性红B的声催化降解来评价复合材料的催化活性,并与单一TiO2的声催化性能进行了比较。结果表明,YFeO3/TiO2-SnO2的声催化活性明显优于单一TiO2或YFeO3/TiO2。并且考察了声催化剂的处理温度和用量,超声照射时间和染料初始浓度等因素对酸性红B降解率的影响。     

载体粒度对钯炭催化剂催化活性的影响

利用钯炭催化剂的苯甲酸加氢反应,考察了活性炭载体粒度(<44μm、44~74μm、74~150μm、>150μm对钯炭催化剂催化活性的影响。采用粒度分析法、BET和SEM对其进行表征,并利用加氢反应釜对其催化剂活性进行评价。结果表明:载体粒度>74μm,金属钯负载不均匀,导致催化剂活性下降;载体粒度<44μm,催化剂不易过滤,洗涤过程活性组分容易脱附,导致催化剂活性降低;载体粒度为44~74μm时,催化剂活性最高。     

稀土复合氧化物燃烧催化剂的性能及表征

浸渍法制备了稀土型燃烧催化剂 ,采用多晶 X射线衍射 (XRD)、程序升温还原 (TPR)、差热热重分析(DTA- TG)、X射线光电子能谱 (XPS)和二甲苯催化氧化活性测试等方法表征了该燃烧催化剂的结构和性能     

Analysis of Product Morphologies and Reaction Mechanisms on Gaseous Reduction of Iron Oxides

It is well established that in gaseous reduction processes solid iron oxides exhibit a wide range of reducibilities. Using the interface stability criteria developed to describe the decomposition of metal compounds in reactive gas atmospheres, together with microstructural evidence obtained under well characterised reaction conditions, the relationships between product structures, and the mechanisms and the kinetics of reduction of iron oxides have been examined. It is shown that the structures and reaction rates can be explained through the occurrence of four principal mechanisms; continuous gas pore formation, dense metal layer growth, discontinuous metal layer breakdown and continuous coupled growth of metal and pores. Through identification of the critical conditions for these different mechanisms, the maximum rates of reduction of a given starting material as a function of temperature, thermal history and gas conditions can be more clearly understood.     

Effects of Cerium on Reduction of Non-Chromium Iron Based CO Shift Catalyst

ＣＯｓｈｉｆｔｐｒｏｃｅｓｓｉｓｏｎｅｅｓｓｅｎｔｉａｌｐｒｏｃｅｓｓｉｎｔｈｅｃｈｅｍｉｃａｌｆｅｒｔｉｌｉｚｅｒｉｎｄｕｓｔｒｙａｓｗｅｌｌａｓｏｔｈｅｒｉｎｄｕｓｔｒｙ .Ｉｎｔｈｅｐｒｅｓｅｎｔｔｉｍｅ ,ｔｈｅｉｒｏｎｃａｔａｌｙｓｔｓｃｏｎｔａｉｎｉｎｇｃｈｒｏｍｉｕｍｉｓｓｔｉｌｌｗｉｄｅｌｙｕｓｅｄｉｎｉｎｄｕｓｔｒｙ .Ａｓｔｈｅｒｅａｓｏｎｐｏｉｎｔｅｄｏｕｔｉｎｔｈｅｐｒｅｖｉｏｕｓａｒｔｉｃｌｅ[1] ,ｔｈｅｒｅｉｓａｇｒｅａｔｉｎｔｅｒｅｓｔｉｎｔｈｅｗｏｒｌｄｔｏｄｅｖｅｌｏ…     

重稀土氧化物对钯催化剂活性影响的研究

研究了重稀土氧化物对钯催化剂活性的影响.实验结果表明,添加重稀土氧化物的钯催化剂,其对CO的氧化活性都有提高,特别是Yb2O3.同Pd催化剂相比,添加Yb2O3的钯催化剂,其CO氧化温度有明显下降.     

纳米TiO2负载钯催化剂的性能研究

采用浸渍法制备了纳米TiO2负载钯催化剂,以乙炔选择催化加氢制备乙烯为反应模型考察了稀土元素La、空速对纳米Pd／TiO2催化剂性能的影响,并与纳米SiO2为载体的Pd—La／SiO2催化剂的性能做了比较。实验结果表明,纳米Pd／TiO2催化剂具有良好的催化活性和性能稳定性,La的加入显著提高了乙烯的选择性、增幅达加％左右。与Pd—La／SiO2催化剂相比,Pd—La／TiO2催化剂具有更高的选择性。     

Catalytic Performance of Ce／Zr Oxides Catalysts for Soot Combustion

Catalytic performances of a series Ce/Zr oxides(CexZr1-xO2 )for soot combustion were investigated. The catalytic activities for soot combustion were affected by both the Ce/Zr ratio and the oxygen storageinvestigated. Thecapability of Ce/Zr oxides. O2-TPD and TG-DTA results indicate that CexZr1-xO2 can release its lattice oxygen continuously and promote soot combustion even no oxygen occurs in the reaction atmosphere. Among these Ce/Zr oxides, Ce0.5Zr0.5O2 has the best catalytic activity, and the ignition temperature of soot combustion was about 410℃, which is close to the practical exhaust temperature of the diesel engine.     

La-Hexaaluminate Catalyst Preparation and Its Performance for Methane Catalytic Combustion

The La-hexaaluminate catalysts with high performance ration method with the buffer solution of NH4HCO3 and NH4OH were synthesized by the modified controllable co-precipimixture as the precipitation agent. The physicochemical properties of catalysts were characterized by the means of BET, XRD, and TPR techniques. With methane catalytic combustion as the probe reaction, the catalytic performances were also tested on a fixed bed, continual flow system. The resuits show that it is a good method to obtain chemical homogeneous hexaaluminate materials by the buffer solution as the precipitation agent. The La-hexaaluminate can be formed at low temperatures ranging from 1050 to 1200 ℃. The cerium introduction plays a great role in the methane catalytic combustion on La-Mn hexaaluminate because of its high oxygen storage capacity property and the well synergic effect between Ce and Mn. However, the CeO2 appears in hexaaluminate through the XRD pattern, which reveals that Ce can not enter the crystal lattice position. Mn introduction improves the methane catalytic activity to a large extent due to its high redox property. When Mn atomic substitution amount for A1 is 2, the hexaaluminate shows the highest activity, and the catalyst possesses good H2 consumption and redox performance. Mn can easily occupy the hexaaluminate crystal position, which reveals that the Mn substitute La-hexaaluminate is a promising high temperature methane combustion catalyst with high activity and good stability.     

La-Ce-Cu复合金属氧化物的结构表征及催化性能

本文用ＮＨ４ＮＯ３共熔法合成Ｌａ－Ｃｅ－Ｃｕ系列样品。用ＸＲＤ分析了ＣｅＯ２在铜酸镧盐中的溶解度,发现大量ＣｅＯ２存在时,Ｌａ２Ｏ３、ＣｕＯ的加入导致原晶体结构发生变形,生成少量铜酸镧盐。ＸＲＦ分析了系列样品组成均为氧缺陷型化合物。ＸＰＳ研究发现,含大量ＣｅＯ２的样品高温焙烧后在ＣｅＯ２表面生成复合金属氧化物Ｌａ２ＣｕＯ４,最表面一层为少量Ｌａ２Ｏ３,并确定了其中Ｏ的属性。利用ＴＥＭ研究了部分样品的表面结构,同时研究了其ＣＯ催化氧化活性。     

Field Study, Design, and Catalyst Cost of Selective Catalytic Reduction Process

A pilot TiO2∕V2O5 based selective catalytic reduction (SCR) system was installed in a glass manufacturing factory. The effects of important operation parameters such as the reaction temperature, space velocity, and inlet NH3∕NOx molar ratio on the NO removal were evaluated. It was observed that >1 mol of NOx is reacted for every 1 mol of NH3 injected. This observation is different from that reported in the literature for laboratory experiments. The key design parameter values of the reaction rate and the NH3 adsorption rate were determined based on results of the pilot tests using a theoretical SCR model developed by the same research group. The SCR model is a simple analytical solution that accounts for the simultaneous mass transfer and chemical reaction of an SCR reactor. The model results were compared to field data of NOx conversion efficiency and NH3 slip, and they were in reasonable agreement. The required catalyst volume and the cost of catalysts were then determined with the assistance of the design model.     

反应条件对钌催化剂和铁催化剂的氨合成性能影响

Activated carbon-supported Ru-based catalyst and A301 iron catalyst were prepared, and the influences of reaction temperature, space velocity, pressure, and H2/N2 ratio on performance of iron catalyst coupled with Ru catalyst in series for ammonia synthesis were investigated. The activity tests were also performed on the single Ru and Fe catalysts as comparison. Results showed that the activity of the Ru catalyst for ammonia synthesis was higher than that of the iron catalyst by 33.5%-37.6% under the reaction conditions: 375-400 ℃, 10 Mpa, 10000 h-1,H2:N2=3,and the Ru catalyst also had better thermal stability when treated at 475℃ for 20 h. The outlet ammonia concentration using Fe-Ru catalyst was increased by 45.6%-63.5% than that of the single-iron catalyst at low temperature (375-400℃),and the outlet ammonia concentration increased with increasing Ru catalyst loading.