NEW EQUATION FOR CORRELATING EXPERIMENTAL DATA WITH TWO VARIABLES

The equation mostly used for correlating experimental data is normal polynomial:f(x,t) = c 0(t) +c 1(t)x+c 2(t)x 2+…+c n(t)x n.However correlation with this polynomial is undesirable when the curved surface formed by experimental data is not smooth or the correlating range of correlation is too large.In this paper, a new correlating equation for this purpose is proposed.There are no undetermined coefficients in the new equation. When this new equation is used for correlating different kinds of experimental data (curved surface), smaller errors will always be obtained in comparison with the normal polynomial

拟合实验数据的新方程——非整数幂多项式方程

将实验数据拟合成方程在科学研究和工程计算上具有十分重要的作用。目前,拟合实验数据最常用的是整数幂多项式f(x)=c_0+c_1x+c_2x~2+…+c_nx~n,但是用此多项式拟合各类数据时有时误差较大。本文提出一个新方程,即双系列非整数幂多项式g(x)=c_0+c_1x~0+…+c_kx~(ka)+c_(k+1)x~[(k+1)b]+…+c_nx~(nb),式中a,b为参数,c_i(i=0,1,2,…,n)为待定系数。在拟合各类实验数据时,新方程总是优于整数幂多项式

A Novel Method for Preparation of Activated Alumina

[中文文摘]将结晶氯化铝与柠檬酸及淀粉等造孔剂混合,经直接干燥和焙烧制得了一种无定形活性氧化铝,并通过X射线粉末衍射、N2物理吸附及氨程序升温脱附等手段对活性氧化铝样品进行了表征,探讨了各组分对活性氧化铝样品性质所起的作用.与常规的活性氧化铝制备方法相比,这种制法省去了中和、老化、过滤和洗涤等步骤,缩短制备周期且过程容易控制.活性氧化铝具有适宜且可调节的比表面积和孔径分布,作为载体负载镍金属组分制成负载型催化剂后,对乙苯加氢饱和与加氢裂化表现出较高的催化活性.[英文文摘]A novel and simple method was developed to prepare alumina with suitable specific surface area and pore size distribution. First,AlCl3·6H2O and citric acid were heated without water in a water bath at 90 ℃ with stirring until a homogenous solution was obtained.Then starch was added into is solution.After the solution was dried at 110 ℃ and calcined at indicated temperature, activated alumina was obtained.The activated alumina was characterized by N2 adsorption,X-ray diffraction,and NH3 temperature-programmed desorption. Compared with the usual technology , this novel preparation did not include some steps such as aging , filtering , and washing. Moreover , the specific surface area and pore size distribution of the activated alumina could be controlled and modified by changing the preparation parameters. The supported Ni/ Al2O3 catalyst with the activated alumina as support showed higher activity for hydrogenation and hydrocracking of ethylbenzene.国家重点基础研究发展计划(973计,2004CB217805); 福建省“百千万人才工程”项目; 福建省自然科学基金(U0750016)

Preparation and Characterization of Presulfidation-Free MoNiP/Al_2O_3 Catalyst for Thiophene Hydrodesulfurization

[中文文摘]在Mo-Ni-P-O浸渍液中添加一定量的极性有机物如柠檬酸等,采用共浸渍法制备了一种不需预硫化和焙烧也具有较高加氢脱硫活性的MoNiP/Al2O3催化剂,并用N2吸附、程序升温还原、X射线光电子能谱、红外光谱和元素分析对催化剂进行了表征.结果表明,柠檬酸的添加削弱了金属组分与载体间的相互作用,有利于金属组分在载体表面的分散,且改善了催化剂的还原性,使催化剂在与含硫反应物料接触过程中自发硫化,从而有利于催化剂加氢脱硫活性的提高.[英文文摘]A new type of MoNiP/Al2O3 catalyst for thiophene hydrodesulfurization was prepared by the co-impregnation method, wherein a suitable amount of citric acid was added in the Mo-Ni-P-O impregnation solution. The catalyst exhibits high activity for thiophene hydrodesulfurization under presulfidation- and calcination-free conditions. The catalyst was characterized by N2 adsorption, temperature-programmed reduction, X-ray photoelectron spectroscopy, infrared spectroscopy, and elemental analysis methods. The effect s of cit ric acid on the structure and activity of the MoNiP/ Al2O3 catalyst were studied. The result s show that the addition of cit ric acid weakens the interaction between the active metal components and support , improves dispersion of active metal component s on the support surface , and promotes the reduction and sulfidation of the catalyst by sulfur-containing feedstocks. Therefore, the hydrodesulfurization activity of the catalyst is improved.国家重点基础研究发展计划(973计划, 2004CB217805); 厦门大学科技创新项目(XDKJCX20051002)

Reactor model with cross-flow for aromatics catalytic hydrogenation

[中文文摘]提出了一种抗硫中毒的芳烃加氢催化反应器模型,称之为交叉流反应器模型,把反应物料分为两股,其中含有噻吩的乙苯物料采用轴向连续流动方式由反应器进口进入催化剂床层,而氢气由铅直导管直接进入催化剂床层中,然后与乙苯物料混合。在氢气导管出口处形成含硫乙苯浓度低而氢气浓度高的特殊区域,因而硫对催化剂的中毒效应大幅度降低,整体上提高了乙苯加氢饱和反应效率。与传统轴向混合流反应器进行比较,在相同条件下交叉流反应器具有更好的整体加氢反应性能。分别建立了交叉流反应器与传统轴向混合流反应器模型,提出了两种反应器的催化反应转化率方程;利用此转化率方程,对实验数据进行处理,得到动力学参数,模型的计算结果与实验数据相吻合,也验证了在交叉流反应器中,硫的中毒效应明显减弱。[英文摘要]A novel reactor model named cross-flow reactor for aromatics catalytic hydrogenation was proposed.The reactants were divided into two flows:ethylbenzene with thiophene was introduced to the catalyst bed along the axial direction of the columnar reactor,while hydrogen was introduced into catalyst bed through a vertical pipe with openings.Because special areas with high H2 pressure and low H2S pressure were formed near these openings,the poisoning of catalyst by thiophene was substantially decreased,and consequently the reaction of et hylbenzene hydrogenation was improved as compared with the traditional reactor with mixed co-flow. Finally , kinetic models were established for this cross-flow reactor and the traditional reactor1And the conversion equations of these two reactors were given.By using these equations , the experiments data were fitted to obtain kinetics parameters. The calculation results agreed well with the experimental data. It was also demonst rated that sulfur poisoning in cross-flow reactor was weakened.国家重点基础研究发展计划项目(2004CB217805); 福建省“百千万人才工程”支持项目; 福建省自然科学基金项目(U0750016)

A Novel Method for Preparation of Activated Alumina

A novel and simple method was developed to prepare alumina with suitable specific surface area and pore size distribution. First, AlCl3 center dot 6H(2)O and citric acid were heated without water in a water bath at 90 degrees C with stirring until a homogenous solution was obtained. Then starch was added into is solution. After the solution was dried at 110 degrees C and calcined at indicated temperature, activated alumina was obtained. The activated alumina was characterized by N-2 adsorption, X-ray diffraction, and NH3 temperature-programmed desorption. Compared with the usual technology, this novel preparation did not include some steps such as aging, filtering, and washing. Moreover, the specific surface area and pore size distribution of the activated alumina could be controlled and modified by changing the preparation parameters. The supported Ni/Al2O3 catalyst with the activated alumina as support showed higher activity for hydrogenation and hydrocracking of ethylbenzene

Preparation and characterization of presulfidation-free MoNiP/Al2O3 catalyst for thiophene hydrodesulfurization

A new type of MoNiP/Al2O3 catalyst for thiophene hydrodesulfurization was prepared by the co-impregnation method, wherein a suitable amount of citric acid was added in the Mo-Ni-P-O impregnation solution. The catalyst exhibits high activity for thiophene hydrodesulfurization under presulfidation- and calcination-free conditions. The catalyst was characterized by N-2 adsorption, temperature-programmed reduction, X-ray photoelectron spectroscopy, infrared spectroscopy, and elemental analysis methods. The effects of citric acid on the structure and activity of the MoNiP/Al2O3 catalyst were studied. The results show that the addition of citric acid weakens the interaction between the active metal components and support, improves dispersion of active metal components on the support surface, and promotes the reduction and sulfidation of the catalyst by sulfur-containing feedstocks. Therefore, the hydrodesulfurization activity of the catalyst is improved

双参数修形对平面二次包络环面蜗杆副蜕变点位置的影响

根据环面蜗杆副啮合方程,解出蜕变点的位置。建立了环面蜗杆副蜕变点参数方程,分别讨论了传动比、中心距单一变化和传动比、中心距同时变化时,蜕变点与蜗轮齿面位置关系,做出了蜕变点随中心距、传动比变化的拟合曲线图,说明了它们之间的变化关系,得出蜕变点随中心距和传动比的增大,离蜗轮齿面越来越远的结论。该结论对于蜗轮齿面的加工、齿面的结构分析、蜗杆副的制造、装配及参数修正都具有重要的现实意义

A Novel Method for Preparing γ-Al_2O_3

经蒸发浓缩氯化铝、氨水与扩孔剂草酸铵的混合溶液,生成氢氧化铝沉淀物,再经加热分解除去NH4Cl,所得粉末成型后在550℃下煅烧转化为γ Al2O3.着重考察扩孔剂加入量,分解温度等对产品性质的影响.与常规制备γ Al2O3方法比较,本方法省去了老化、过滤、洗涤等步骤,具有缩短制备周期、保护环境等优点.本方法所制γ Al2O3孔体积大,孔分布集中,压碎强度高.A novel method for preparingγAl2O3 is provided with the procedure as follows :(1) a mixing solution composed of AlCl3,NH+4,H2O and ammonium oxalate is concentrated by heating and resulting in the deposition of Al(OH)3;(2)drying the deposit;(3)decomposing the deposit and NH4Cl being retrieved;(4)the powder from step(3)being pelleliged(5)calcining the pellet at 550℃ for 4hr.Compared with the usual technology,this new method has the advantages of needlessness of preparing steps such as aging,filter and washing,and the dispose of the washing liquid.The γAl2O3 obtained by the method is characterized by large pore volume,narrow pore distribution and high crushing strength for pellet

Methods of Deriving a Reaction Mechanism from Its Rate Equation

将化学反应视为抽象的“化学流”,提出“完全速率方程”的概念,并阐述其物理意义,考察了完全速率方程的各种破缺形式及其所对应的反应历程的特性及自催化作用对速率方程的影响.通过举例说明,归纳总结了由速率方程推演反应历程所应遵循的原理和规则.Supposing that the concentrations of intermediates are invariable during the course of a chemical reaction,there will be a rate equation with full form called full rate equation:γ_(ful)=(F_f-F_b)/(F_(m-f)-F_(m-b)).The full rate equation,if a chemical reaction is regarded as chemical flow,has its physical meanings.F_f 、F_b、F_(m-f)、F_(m-b) can be called forward full-flow,backward full-flow,forward flow of decreasing intermediates and backward flow of decreasing intermediates respectively.F_f is defined as multiplication of the forward rate equation of every element reaction(ER) and the definitions of F_b、F_(m-f) and F_(m-b) are in analogy to F_f.The reaction mechanism(pathway) corresponding the full rate equation has three features:(1) every ER is reversible;(2) at least one molecule of reactants does not take part in first-step ER;(3) at least one molecule of products does not emerge in last-step ER.In most cases,the full rate equation appears as a certain kind of short forms.For example,if at least one of ERs is irreversible,then F_b=0.According to the physical meanings of rate equation and the understanding of the intermediates of the reaction concerned,we can easily derive the reaction pathway.Meanwhile the effects of autocatalysis on the form of the rate equation are also discussed