Fe_2O_3对CuO/CeO_2水煤气变换催化剂的改性研究

采用活性评价、BET、H_2-TPR研究了Fe_2O_3对CuO/CeO_2水煤气变换催化剂的活性、结构及还原性的影响。结果表明:添加适量Fe_2O_3有助于催化剂活性提高,Fe_2O_3的添加降低了催化剂的比表面积、孔容及平均孔径,Fe_2O_3的添加使催化剂的H_2还原性能发生了较大的变化,随含量增加从细微调变到明显的质变。     

CrO_x/Al_2O_3丙烷脱氢催化剂性能研究

采用浸渍法制备了一系列CrO_x/γ-Al_2O_3催化剂样品,使用BET、XRD、XRF、XPS、SEM、NH3-TPD、UV-Vis、FT-IR等技术对催化剂进行了表征,在固定床反应器上考察了Cr_2O_3负载量及反应条件对催化剂的丙烷脱氢反应性能的影响。结果表明,活性组分在催化剂中主要以Cr_2O_3形式存在,为获得最好的催化脱氢性能,催化剂中Cr_2O_3最佳质量分数为18%~20%,最佳反应温度为590~610℃、丙烷体积空速为750~1000h-1。通过活性位分析,表明催化脱氢反应主活性位是硬Cr~(6+)和Cr~(3+)。硬Cr~(6+)的活性比Cr~(3+)高,然而随反应进行硬Cr~(6+)也会被还原,这导致催化活性逐渐降低。     

负载型硫酸铁对烯烃齐聚催化作用的研究 Ⅳ.不同方法制备的 Fe_2(SO_4)_3/γ-Al_2O_3 的丙烯齐聚反应的考察

考察了不同方法制备的Ｆｅ２（ＳＯ４）３／γ－Ａｌ２Ｏ３和Ｆｅ２Ｏ３Ｆｅ２（ＳＯ４）３／γ－Ａｌ２Ｏ３催化剂对丙烯齐聚反应的催化性能。结果表明，Ｆｅ２（ＳＯ４）３／γ－Ａｌ２Ｏ３的制备方法对催化剂的催化活性有很大的影响。与直接将Ｆｅ２（ＳＯ４）３担载于γ－Ａｌ２Ｏ３上的制备方法相比，先担载Ｆｅ（ＮＯ３）３于γ－Ａｌ２Ｏ３上，焙烧后再担载（ＮＨ４）２ＳＯ４，再焙烧；或先用氨水将Ｆｅ２（ＳＯ４）３溶液调至ｐＨ＝１．２后形成胶体、再担载于γ－Ａｌ２Ｏ３上制备的Ｆｅ２（ＳＯ４）３／γ－Ａｌ２Ｏ３催化剂的活性都有明显的提高，这些催化剂表现出更强的酸性。用铝胶替代γ－Ａｌ２Ｏ３浸渍于Ｆｅ２（ＳＯ４）３溶液中，焙烧后制得的Ｆｅ２（ＳＯ４）３／γ－Ａｌ２Ｏ３也表现出较高的活性，其酸量增大。当Ｆｅ２Ｏ３Ｆｅ２（ＳＯ４）３／γ－Ａｌ２Ｏ３催化剂中Ｆｅ２Ｏ３与Ｆｅ２Ｏ（ＳＯ４）３的Ｆｅ原子比为１５、１２、１１时，催化剂表现出较高的丙烯齐聚催化活性。此类催化剂上出现超强酸中心。强酸中心的增强归于Ｆｅ２Ｏ３与ＳＯ２－４的相互作用。     

Pd/Nb_2O_5—Al_2O_3催化剂合成MIBK的研究

研究了Pd/Nb_2O_5—Al_2O_3催化剂的制备方法及用于丙酮加氢合成MIBK的催化性能。实验结果表明,在反应温度160℃,反应压力4 MPa条件下,丙酮单程转化率为40％,MIBK选择性为92％。     

SO_4~(2-)/Fe_2O_3超强酸催化剂的制备及其对乙酸/丁醇酯化反应的催化作用

SO_4~2/Fe_2O_3超强酸是由3种来源的Fe_2O_3制备而成。研究了H_2SO_4浓度、焙烧温度、以及其它制备条件对催化活性的影响。实验结果表明:3种SO_4~(2-)/Fe_2O_3对乙酸/丁醇的酯化反应均有活性。最佳结果是在2h之内,转化率>90％。经XRD分析,在SO_4~2/Fe_2O_3中无硫酸盐存在。     

临氢脱烷基废Cr_2O_3/Al_2O_3催化剂再生处理的研究

利用正交实验确定了Cr_2O_3/Al_2O_3废催化剂加工处理的工艺条件及助剂组分与加入量,得到的经过加工处理的废催化剂,其活性和抗积炭能力等性能甚至优于新催化剂。实验发现,在催化剂中引入NiO可提高其加氢裂解能力;CeO_2的引入可提高其抗积炭能力;MgO的引入可稳定催化剂中的NiO,从而提高了催化剂的选择性。     

脉冲化学吸附法研究苯和甲苯在Cr_2O_3/Al_2O_3催化剂上的吸附

XRD和脉冲化学吸附法测定苯和甲苯在Cr_2O_3/Al_2O_3催化剂的化学数据表明,随着催化剂中Cr_2O_3含量的增加,Cr_2O_3在Al_2O_3表面上的晶粒度逐渐变大,苯和甲苯在催化剂上的吸附强度相对也逐渐减弱,而吸附中心的数目呈上升趋势。该法在催化剂的研制和开发工作中可用于比较氧化物催化剂对反应物或产物的相对吸附强度和吸附中心数目。     

甲苯在V_2O_5/α-Al_2O_3催化剂上的选择性氧化V_2O_5负载量对催化剂性能的影响

研究了 V2 O5 / α Al2 O3催化剂用于甲苯气相选择性氧化反应时 V2 O5 负载量对其催化性能的影响。并通过 BET、TPR等测试手段 ,讨论了催化剂的物化结构与催化性能。结果表明 :适宜的 V2 O5 负载量为 1 1 .4 %( w)左右     

La_2O_3催化剂上乙烷氧化脱氢反应的研究

考察了乙烷在Ｌａ２Ｏ３催化剂上的氧化脱氢反应，催化剂表面积４～５２ｍ２／ｇ，反应温度７０３～７９３Ｋ，主要产物为Ｃ２Ｈ４、ＣＯ２、ＣＯ和Ｈ２Ｏ，反应温度高时可检测到ＣＨ４。催化剂表面积增加，其固有活性（单位表面积上的转化率）下降，而对乙烯的选择性几乎不变，反应是纯化学性质的表面反应，选择氧化和深度氧化可能经相同活性中心进行，该活性中心可能是处于平面位置上具有高配位数的离子，另就反应涉及到的某些化学问题提出一些见解。     

Al_2O_3-TiO_2为载体的前加氢催化剂研究

采用共沉淀法制备Al2 O3-TiO2 混合载体。该载体具有较大的比表面积 ,用其制备的钯系催化剂对于炔烃和二烯烃的选择加氢具有较高的加氢活性和选择性。XRD结果表明 ,混合载体中Al2 O3 为无定形 ,TiO2 为 β型。用压汞法测定其存在双峰孔径分布     

KINETICS FOR FAST PYROLYSIS OF HAZEL NUT SHELL

In this article, the potential utilization of hazel nut shell as a combustible residue was studied. To obtain liquid and gaseous products, the hazel nut shell was subjected to pyrolysis and it was converted to 49.3 % (w) gaseous and 20.0 % (w) liquid products at 475 °C for 7.5 minutes in a simple pyrolysis device The kinetic model used in the present study was based on fractional weight loss for each pyrolysis step. The simple fast pyrolysis was compared with TGA technique.     

KINETICS FOR FAST PYROLYSIS OF HAZEL NUT SHELL

Abstract

In this article, the potential utilization of hazel nut shell as a combustible residue was studied. To obtain liquid and gaseous products, the hazel nut shell was subjected to pyrolysis and it was converted to 49.3 % (w) gaseous and 20.0 % (w) liquid products at 475 °C for 7.5 minutes in a simple pyrolysis device The kinetic model used in the present study was based on fractional weight loss for each pyrolysis step. The simple fast pyrolysis was compared with TGA technique.     

反应条件对钴钼催化剂选择性加氢脱硫性能的影响

在固定床加氢微反装置上,采用工业CoMo/Al2O3催化剂,以含硫和烯烃的模型化合物为原料考察反应条件对钴钼催化剂选择性加氢脱硫性能的影响。结果表明,适当增大反应空速、降低反应压力、提高氢油比、提高催化剂的硫化温度均有利于降低烯烃的加氢饱和反应活性,从而有利于催化剂选择性加氢脱硫活性的提高。另外,当原料中烯烃含量提高时,烯烃与噻吩在活性中心上的竞争吸附加剧,烯烃加氢饱和性能增强,导致加氢脱硫选择性降低。     

NiW/Al2O3上喹啉对二苯并噻吩 加氢脱硫的抑制作用及反应动力学

 以二苯并噻吩(DBT)为含硫模型化合物，在中压滴流床反应装置中研究了工业NiW/Al₂O₃催化剂(RN-10)上喹啉对DBT加氢脱硫(HDS)的抑制作用，考察了喹啉质量分数(0.5%~1.5%)、反应温度(290~380℃)、反应压力(4.0~5.6MPa)对DBT的HDS的影响。结果表明，喹啉的存在对于DBT的HDS反应有很强的抑制作用，且喹啉浓度越高，抑制作用越大；对DBT的先加氢饱和再脱硫路径(HYD)的抑制作用比对直接脱硫路径(DDS)更大；提高反应温度对DDS和HYD路径的脱硫活性均有提升，但由DDS路径生成联苯的选择性降低；较高反应压力有利于提高HYD路径产物的选择性。采用带有氮化物吸附(中毒项)的拟一级反应动力学模型对实验数据进行拟合，得到不同喹啉质量分数下DBT的HDS表观反应速率常数。经检验，模型计算结果与实验结果吻合。     

Fe-Cu催化剂催化苯酚羟基化的反应动力学研究

苯酚-H2O2羟基化联产邻苯二酚和对苯二酚是目前最有前途的合成苯二酚的绿色工艺路线之一。采用已开发成功的Fe-Cu金属酸盐催化剂，在无梯度反应器中，通过改变反应温度、苯酚／H2O2摩尔比、苯酚初始质量分数3个因素，系统考察了Fe-Cu和Fe-Cu／Al2O32种催化剂催化苯酚-H2O2羟基化的反应动力学过程。结果表明，在相同的M／FAo（M为催化剂质量，FAo为反应器入口关键组分A的流量）条件下，反应温度升高、苯酚／H2O2摩尔比减小、苯酚初始质量分数增大，都会使得苯酚转化率升高，相应的苯二酚的选择性也会有所下降。预测了Fe-Cu催化剂催化的苯酚羟基化反应机理，推导出苯酚羟基化反应动力学方程，并拟合出相关反应动力学参数。     

Pd/Al2O3催化过氧化氢异丙苯的液相加氢反应

 分别以K₂[PdCl₄]和K₂[PdCl₄]与草酸的混合液为Pd前驱体,采用浸渍沉淀法制备了Pd/Al₂O₃催化剂。采用等离子体耦合发射原子吸收光谱(ICP-AES)、透射电镜(TEM)、程序升温还原(TPR)等手段对Pd/Al₂O₃催化剂进行了表征。考察了Pd/Al₂O₃催化剂在过氧化氢异丙苯(CHP)固定床加氢反应中的催化活性。结果表明,金属Pd在载体Al₂O₃上呈不均匀分布,并发生团聚,其颗粒直径为5～10nm;催化剂在煅烧及还原过程中,活性金属Pd与载体Al₂O₃发生强烈相互作用,产生了Pd-Al合金。以K₂[PdCl₄]为前驱体制备的Al₂O₃催化剂在过氧化氢异丙苯(CHP)固定床加氢反应中显示了较高的二甲基苄醇(CA)选择性,而且在240 h 连续反应过程中,CHP的转化率始终维持在100%,目标产物CA的平均选择性也达到了97.7%。通过对比反应前后反应体系的组成,探讨了CHP液相催化加氢制备CA的反应途径。     

REACTION KINETICS FOR OLEFIN HYDROGENATION OVER COBALT-MOLYBDENUM HYDROTREATING CATALYST AND MODEL STUDY OF CATALYST PROPERTIES

Intrinsic kinetic data for propylene hydrogenation over a CoMof Al₂ O₃ catalyst were measured in a plug-flow integral reactor at atmospheric pressure in the ranges of temperature and propylene concentration similar to industrial processes. The parameters of several Langmuir-Hinshelwood kinetic models derived from postulated corresponding reaction mechanisms were estimated by DFP variable measurement method. It was shown in view of physical meaning, variance and residue analysis that the data could be simulated satisfactorily by power law model and the models derived from the adsorption of only either molecular hydrogen or dissociated hydrogen. A kinetic optimization method which combined diffusion-reaction model, kinetic data, pore-size distribution and tortuosity factor was proposed in this paper to calculate the intraparticle reaction dead region and intraparticle concentration profiles. The method was used to treat hydrogenation reaction and the model values of tortuosity factor were justified by single pellet string     

REACTION KINETICS FOR OLEFIN HYDROGENATION OVER COBALT-MOLYBDENUM HYDROTREATING CATALYST AND MODEL STUDY OF CATALYST PROPERTIES

ABSTRACT

Over the years, several analytical methods have been applied to various heavy crude oil residua and their processed products to understand the chemistry behind residuum upgrading processes. The ultimate aim has been to predict prccessability of specific feeds. However, few, if any analytical methods have been found which adequately perform this task. This paper examines selected processing experiments by the following techniques – clusion chromatography with element specific detection, D 2007-80 with as-phaltene precipitation (SARA) separation, hydrogen distribution and incorporation by NMR – cusses whether the analytical technique has any potential to predict prccessability

From the size exclusion chromatography with element specific detection studies, an intimate relationship appears between the catalyst pore size and molecule size based on examination of the size behavior of feeds and pilot-plant products. From the D 2007-80 and asphaltene separations, the quality of asphaltenes appears to be related to the relative ease of processability of at least two different feeds. From the hydrogen distribution studies, hydrogen utilization was found to be feed dependent and could be directed by processing type. All these trends have some potential towards the formulation of a residuum processability scheme, however no method is as yet globally satisfactory.     

REACTION KINETICS FOR OLEFIN HYDROGENATION OVER COBALT-MOLYBDENUM HYDROTREATING CATALYST AND MODEL STUDY OF CATALYST PROPERTIES

ABSTRACT

Intrinsic kinetic data for propylene hydrogenation over a CoMo / Al₂O₃ catalyst were measured in a plug-flow integral reactor at atmospheric pressure in the ranges of temperature and propylene concentration similar to industrial processes. The parameters of several Langmuir-Hinshelwood kinetic models derived from postulated corresponding reaction mechanisms were estimated by DFP variable measurement method. It was shown in view of physical meaning, variance and residue analysis that the data could be simulated satisfactorily by power law model and the models derived from the adsorption of only either molecular hydrogen or dissociated hydrogen. A kinetic optimization method which combined diffusion-reaction model, kinetic data, pore-size distribution and tortuosity factor was proposed in this paper to calculate the intraparticle reaction dead region and intraparticle concentration profiles. The method was used to treat hydrogenation reaction and the model values of tortuosity factor were justified by single pellet string reactor experiments. Research work showed that kinetic optimization method was effective for analysis of any reaction system over arbitrary shapes of catalysts.