锆钒蓝色料中钒的价态研究

锆钒蓝色料是一种稳定的高温釉用色料,它具有稳定的锆英石晶体结构。本研究采用X射线衍射分析、光电子能谱及分光光度法研究了锆钒蓝色料的呈色机理。结果表明,由于钒的掺杂,V^4 置换了锆英石晶格中的部分Zr^4 ,使[ZrO6]八面体变形,导致色料在反射光谱的可见光475nw周围形成一个宽的反射峰,从而使色料呈蓝色。     

铬锡红色剂中铬的价态研究

Ｃｒ－Ｃａ－Ｓｎ－Ｓｉ系玛瑙红颜料是一种稳定的高温陶瓷色剂,它具有稳定的锡榍石晶体结构,本研究采用电子自旋共振,光电子能谱、Ｘ射线衍射分析及分光光度法研究了玛瑙红色剂的呈色机理,结果表明,由于铬的掺杂,Ｃｒ＾４＋置换了锡榍石晶格中的Ｓｎ＾４＋,使「ＳｎＯ６」八面为形,结果导致色剂在反射光谱的可见光５２０ｎｍ周围形成一条宽的吸收带,从而使釉呈玛瑙红色。     

耐火材料中铝的化学分析方法研究

近年来,耐火材料的理化性质测定方法不断改进,为适应其发展的需要,主要介绍了耐火材料中铝的分析方法以及各种分析方法的特点,讨论了测定铝的影响因素;从而为不同的耐火材料中铝的分析方法的确定以及耐火原料级别和品位的评定提供重要依据.     

照相明胶中硫存在形态的XPS研究

本文采用Ｘ射线光电子能谱技术,研究了国内外典型的两种照相明胶的空白样品、掺杂铁（Ⅲ）的样品中硫元素的存在形态．硫在明胶中主要以三种化学形态存在：蛋氨酸砜中的ＳＯＯ基团,蛋氨酸亚砜中的ＳＯ基团,蛋氨酸中的－Ｓ－基团．三种化学形态间的相对含量基本上反应出蛋氨酸及其两种氧化产物之间的相对比例．在我们的实验条件下,外来三价铁,引发部分蛋氨酸砜被还原为蛋氨酸亚砜,与此同时,明胶中的－ＣＨ２－基团部分氧化为ＣＨＯＨ基团     

MODELING OF THE TRANSIENT AND STEADY STATE OPERATION OF A FLUIDIZED BED REACTOR WITH ADAPTIVE CONTROL OF TEMPERATURE

This paper concerns modeling of the transient and the steady state operation of a fluidized bed reactor for the catalytic ammoxidation of propylene to acrylonitrile. To maintain constant the temperature of the reaction in order to facilitate the phenomenological study as well as to avoid risks of destruction of the catalyst, a self tuning P.I.D. controller has been used. The controller derived from a discrete P.I.D. regulator is based on pole assignment. It uses a recursive parameter estimator based on the least square method. The reactor has been interfaced with an Apple II micro-computer. The results obtained illustrates the inherent capability of self adaptive control to adapt the change of the environment where conventional control fails

Modeling of the reactor is based on the Kato and Wen bubble assemblage model corrected by including the wake of the bubbles with their clouds, as proposed hy Stergiou. This modified model gives good predictions of the operation of the reactor for steady as well as transient operation.     

EFFECT OF GAS-SIDE RESISTANCE ON STEADY STATE MULTIPLICITY IN GAS-LIQUID CSTRs

The effect of gas-side resistance to mass transfer on the existence and uniqueness of steady states in gas-liquid CSTRs is analyzed. It is shown that there exists an upper bound on gas-side resistance beyond which multiplicity cannot arise.     

气液固三相磁稳定流化床的操作状态对反应结果的影响

以氮气、水、铁粉为气液固三相研究了三相磁稳定流化床的床层操作状态；以重整生成油的烯烃饱和加氢过程为体系，研究了铁粉与大比表面非晶态合金催化剂混合颗粒为固相的磁稳定流化床中床层操作状态对反应结果的影响。找到了有利于气液固三相反应的磁稳定流化床床层操作状态     

ESTIMATION AND LOCALIZATION OF MAXIMUM TEMPERATURE IN A TUBULAR CHEMICAL REACTOR BY LUENBERGER STATE OBSERVER

This study deals with an observer built for distributed parameter systems described by nonlinear representations. This observer was applied to a tubular chemical reactor in order to estimate the maximum temperature of the reactant mixture and its position in stationary and transient regimes. This estimation uses a Luenberger observer, while MacCormack's numerical method was used for resolution of the partial differential equations. Furthermore, to take into account the nonlinearity of the system, the gain of this estimator was proposed as a function of the position along the chemical reactor. This observer requires the values of both concentration and temperature at the inlet but only of temperature at the outlet. The convergence and robustness of this estimator were experimentally tested with initialization and modeling errors.     

丙烯氨氧化工艺浅析和反应器设计

在阐述丙烯氨氧化反应机理的基础上,讨论了影响过程变化的内外诸因素,如催化剂的组成和结构、反应温度、压力等。介绍了用来描述丙烯氨氧化的K-L教学模型以及反应器设计和设计参效的取值经验。     

有限元方法求解化学气相淀积反应器模型(Ⅰ)——冷壁反应器模型及有限元解

建立了冷壁化学气相淀积反应器的数学模型,用Galerkin有限元方法对模型予以求解.计算中考虑了温度对物性参数的影响及自然对流因素,计算值和实验结果基本上一致.     

有限元方法求解化学气相淀积反应器模型(Ⅰ)——冷壁反应器模型及有限元解

建立了冷壁化学气相淀积反应器的数学模型,用Galerkin有限元方法对模型予以求解.计算中考虑了温度对物性参数的影响及自然对流因素,计算值和实验结果基本上一致.     

THE ROLE OF GAS DISTRIBUTION IN FLUIDIZED BED CHEMICAL REACTOR DESIGN†

The design of fluid bed gas distributors may have a marked influence on the performance of a fluid bed reactor. The primary physical reason for this influence is that the distributor design influences the hydrodynamics and thus the gas/solid contacting pattern in the fluidized bed.

In the paper presented here the influence of distributor design on mass transfer and chemical reaction has been investigated systematically in fluid bed reactors with diameters of 0.2 and 1.0 meter. Coefficients of mass transfer between the bubble phase and the suspension phase were determined from chemical conversion and tracer gas residence time distribution measurements. In the experimental program the height of the fluidized bed was varied between 0.3 m and 0.9 m with superficial gas velocities in the range of 0.06 m/s to 0.30 m/s.

The comparison of the experimental results with a suitably modified and extended two-phase model yields quantitative relationships which allow to account for the influence of the gas distributor in the design of fluid bed chemical reactors.     

FIXED POINT METHOD IN STEADY STATE ANALYSIS. APPLICATION TO CATALYST PELLETS

An integral equation method is proposed for evaluating concentration distributions inside catalyst pellets. For low Thiele moduli this method is proved to be strictly contractive. For high Thiele numbers a regularization procedure is discussed. Numerically, the implementation of the algorithm reduces to an iterative procedure which is algorithmically simple and accurate. The problem of the multiplicity of steady states can be treated within the framework of the present method. Some examples of application are developed.     

微分反应器中多相催化反应动态过程的模拟分析

动态响应方法可以为多相催化反应过程提供较多的反应机理的信息。与实验研究顺序相反,本文通过模拟微分反应器中多相催化反应的动态过程,分析了不同基元反应速率常数对 Eley-Riddeal 型机理和 Langmuir-Hinshelwood 型机理的动态响应曲线的影响。以利于阐述动态响应方法的基本思想。     

STEADY STATE MULTIPLICITY FEATURES OF ETHYLENE OXIDATION ON PLATINUM FOIL

The catalytic oxidation of ethylene to carbon dioxide in excess air has been studied atsteady state.The catalyst temperature was measured for various feed temperature and concentration.The bifurcation diagrams Which describe the dependence of the catalyst temperature on the feed gastemperature were obtained for different ethylene concentrations in the feed gas.The ignition and ex-tinction temperatures were found out and the unique and multiple steady state regions could bedetermined from these diagrams.The experimental results can be satisfactorily explained by thecatastrophe theory and singularity theory.According to the steady state multiplicity features an at-tempt to discriminate the competitive kinetic models was made for the reaction.     

单颗粒催化剂多定态特性的理论分析

借助于奇异理论和突变理论,本文对单颗粒催化剂的多定态特性进行了分析。得到了反应为一级不可逆放热反应时系统定态模型方程解的结构以及可能具有的歧化图型式;对非一级反应系统,利用区域搜索算法得到了其系统定态模型方程突变集合在操作参数平面上的投影图,分析了反应动力学表达式及动力学参数的变化对体系多定态特性的影响。     

管式反应器合成一氯频那酮工艺研究

采用管式反应器,以频那酮和氯气为原料合成一氯频那酮,系统地考察了影响反应的主要因素,提出了适宜的反应条件,结果表明,该法反应选择性好,产品纯度达９７％以上,过程易于控制。     

STEADY STATE AND DYNAMIC MODELLING OF A PACKED BED REACTOR FOR THE PARTIAL OXIDATION OF METHANOL TO FORMALDEHYDE I. MODEL DEVELOPMENT

Several levels of mathematical models involving one and two dimensions as well as single and multiple phases are used to predict the steady state and dynamic behavior of a packed bed reactor for the partial oxidation of methanol to formaldehyde. Parametric sensitivity is examined for several heat and mass transfer parameters, kinetic parameters, and operating conditions. Yield is compared for various models, and significant differences are observed between the one-dimensional and two-dimensional models. The dynamic behavior after step changes in the operating conditions is found to be qualitatively similar for different models.