THE SWELLING BEHAVIOR OF (W/O)/W LIQUID SURFACTANT MEMBRANE(Ⅰ)MODELING OF THE PERMEATION-SWELLING PROCESS

Water transfer through the organic phase of kerosene containing surfactant Span 80,L113B and certain carrier wasstudied theoretically and experimentally in(W/O)/W liquid surfactant membranes.The process of swelling owing to os-motic pressure can be pictured as solubilization of water in membrane phase caused by surfactant and certain carriers andthen diffusion of it through the membrane between the two aqueous phases due to the gradient of chemical potential.Amathematical model for estimating the permeation-swelling rate has been developed.This mathematical model does notcontain any adjustable parameters and the predicted values agree well with the experimental data of Fujinawa et al.,Xinsheng Ma and Yajun Shi and the authors.Using an apparatus developed for measuring the solubility of water in membrane phase,data for solubilization ofwater in oil caused by some surfactants and carrier were measured.     

MODELING OF ELEMENTARY PROCESS KINETICS FOR METHANOL SYNTHESIS ( Ⅰ )IDENTIFICATION OF STRUCTURE OF ELEMENTARY STEP SEQUENCE

采用动态原位红外测试技术和TPD、TPSR方法,系统地研究了合成甲醇有关物种H_2、CO、CO_2和CH_3OH在铜基催化剂上的吸附与反应特性,判识了反应过程中在催化剂活性表面上的吸附态中间物的类型。在实验信息的基础上,提出了在催化剂活性表面上可能的基元过程序列结构。     

NUMERICAL MODELING OF COUPLED MOMENTUM,HEAT AND MASS TRANSPORT IN FALLING FILM CRYSTALLIZATION PROCESS (Ⅱ)SIMULATION

采用液固二相分区域统一模型 ,以二元有机熔体 (萘 -硫茚 )为例 ,对实验管式降膜结晶器的动量、热量和质量传递过程进行了数值模拟 ,获得了液相区和固相区随时间的变化和枝晶状液固两相区内固相含量的变化及全场温度分布以及主组分萘分布及流场速度分布随时间的变化 .由积分得到的结晶层厚度及萘纯度与相应的实验数据进行了比较 ,所得结果在未引入任何经验常数的条件下与实验结果符合较好 .所建立的液固二相分区域统一模型可以较好地处理实际降膜结晶过程中枝晶状固液两相共存区晶体生长现象及不规则液固相变界面     

CHARACTERIZATION OF MEMBRANE FOULING PROCESS BY ζ-POTENTIAL

<正>对于膜污染机理及其解决方法的研究是膜分离技术研究领域中的一个重点问题.已有的研究主要从膜的材料特性、待分离体系的物化特性及操作方式与条件等3个方面来考察膜污     

KINETIC MODELING OF HYDROISOMERIZATION OF C\-8AROMATICS(Ⅰ)MODELING AND ESTIMATION OF RELATIVE RATE CONSTANTS BY THE WEI-PRATER METHOD

1 Introduetlon To date,most kinetie investigations ofC一aromaties hydroisomerization over bifunetionaleatalysts have been eoneerned with reaetjon meehanisms.R6bsehl巨ger et al.[,]studied thehydroisomerization kineties under sPecifie eonditions,and ProPose…     

APPROXIMATE ANALYTICAL SOLUTION OF EFFECTIVENESS FACTOR FOR POROUS CATALYST (Ⅰ) APPROXIMATE EXPRESSION

The asymptotic solution of isothermal effectiveness factor for one dimensional catalyst pellet can bedetermined by use of perturbation method when Thiele modulus is very large or very small.Taking theinformation given by these asymptotic solutions,a new approximate expression of effectiveness factor hasbeen derived as follows(?)This expression is feasible for the whole range of Thiele modulus and its accuracy is very satisfactoryin comparsion with the exact solution obtained for first order reaction.The physical meaning of the as-sumptions given to the above expression of the system has been fully considered,so that the main defectsencountered in the approximate expressions published in literature have completely been overcome.Ourexpression can be conveniently applied to most of the practical calculations with reliability.     

SYNTHESIS OF REACTOR NETWORK FOR WASTE MINIMIZATION(Ⅰ) GEOMETRY EXPRESSION OF REACTION AND MIXING PROCESS

将废料最少问题分别等同于选择性、相对选择性和瞬时选择性等多个目标 ,根据目标函数的定义和在状态空间内反应、混合加工的几何特征 ,导出了全混流反应器 (CSTR)和微分侧流反应器 (DSR)两种极限情况下的浓度变化轨迹方程 ,同时满足这两个方程 ,可作为反应器系统选择性最大的判据     

KINETICS OF METHANOL SYNTHESIS IN THE PRESENCE OF C301 Cu-BASED CATALYST (Ⅰ) INTRINSIC AND GLOBAL KINETICS

The intrinsic and global kinetics of methanol synthesis from carbon monoxide, carbon dioxide and hydrogen in the presence of C301 commercial catalyst is studied. The investigation is performed under typical commercial conditions in an isothermal plug-flow integral reactor and an     

MODELING OF UNSTEADY - STATE OXIDATION PROCESS OF SO_2(Ⅳ) MODEL PARAMETER MODIFICATION AND PERFORMANCE PREDICTION OF ONE - STAGE FLOW REVERSAL REACTOR

模拟计算证明,反应器操作特性对传热参数的变化是不敏感的,但对化学反应宏观动力学参数的变化是敏感的.通过使模型预测结果与大量模试数据相拟合的办法修正了宏观动力学参数.利用所发展的数学模型和修正后的参数,对单级反应器的操作性能进行了预测与分析,所得到的结论对工业反应器的设计、运行和优化具有指导作用.     

THE INFLUENCE OF PROCESS PARAMETERS ON THE INTERFACIAL CHEMISTRY OF γ-GPS ON ALUMINIUM: A REVIEW

Within the “International Collaborative Programme on Organosilane Adhesion Promoters” (ICOSAP), scientists from the U.S. and Europe contributed to the understanding of an organosilane primer process, based on an aqueous solution of γ-glycidoxypropyl trimethoxysilane (γ-GPS), used currently for aerospace repair purposes. Parameters such as temperature of cure, ageing time, and concentration of the aqueous solution have been investigated, and this work reviews the effect that each variable has on the process, and the resulting integrity of the GPS/aluminium interface. The aim of the work was to provide a more environmentally friendly replacement for pretreatments containing Cr(VI) that are currently used, such as chromic acid anodising and acid etching employed for the structural adhesive bonding of aluminium.

The formation of covalent interfacial bonding is shown to be a function of the hydrolysis and condensation of the silane molecules in solution as well as the type of solvent used. The curing temperature of the aqueous film on the aluminium is also shown to have an effect on the chemistry of the resulting primer film and its efficacy as an adhesion promoter. All these parameters must be optimised to obtain durability that matches that obtained by a phosphoric acid anodising pretreatment. This work reports on the various studies performed towards this aim carried out within the remit of the ICOSAP initiative, with a particular emphasis on the interfacial chemistry between γ-GPS and the aluminium substrate, and indicates the manner in which the results point the way towards a viable, environmentally friendly pretreatment for the adhesive bonding of aluminium for aerospaceapplications.     

INFLUENCE OF CATALYST DEACTIVATION ON THE NATURE OF THE STEADY STATE SOLUTIONS FOR REACTIONS ON CATALYTIC SURFACES†

Densities of solutions of CaCl₂ in the mixtures of water and methanol have been measured at 25°C and the apparent molar volume of solute, φ_v, was calculated. Experimental concentration dependence of φ _v was compared with the coefficient S_v derived from the Debye-Hückel theory. The relation between φ_v — S_vc^1/2 and c is linear but the slopes changed from horizontal to gradually negative with increase of the methanol content in the solvents, showing that in addition to interionic interactions expressed by the D-H theory, some types of solute-solute interactions are working in the solutions. V _2? of CaCl₂ decreased remarkably in the methanol-rich regions. This is ascribable to the strong electrostricion effect of Ca²⁺ ion in solutions.     

GRAPHICAL TECHNIQUE FOR MODELING INTEGRATING (Non–SELF-REGULATING) PROCESSES WITHOUT STEADY-STATE PROCESS DATA

Model-fitting techniques for controller tuning that require the process to be initially at steady state cannot generally be used with integrating (non–self-regulating) processes. To address this issue, a graphical model-fitting technique is detailed and demonstrated for determination of first order plus dead time integrating model parameters from integrating process response plots. The resulting model parameters can be used directly in a range of tuning correlations designed specifically for integrating processes. The advantage of this technique is that it requires only two periods of constant manipulated and disturbance variables sustained just long enough for the process variable to respond and establish a clear slope. This is an important benefit because integrating processes generally cannot be maintained at an initial steady state as required when using techniques published for self-regulating processes. The result is an industry-friendly method. The method is demonstrated for level control in a pumped tank, a classical challenge in industrial practice. Both a simulation and a bench-scale experimental system are used in the demonstration studies.     

MODELING OF ELEMENTARY PROCESS KINETICS FOR METHANOL SYNTHESIS (Ⅱ )A TRANSIENT KINETIC MODEL OF METHANOL SYNTHESIS FROM CO/CO_2/H_2

在基元过程序列结构判识的基础上,以傅立叶变换红外光谱仪(FTIR)气体池作为检测器,采用动态响应技术,进行了合成甲醇过程瞬态动力学的实验研究,得到了微型反应器尾气中各主要物种的浓度对反应器进料浓度阶跃变化的动态响应数据。基于瞬态速率模型对实验数据的拟合,得到了由H_2/CO/CO_2合成甲醇初步的瞬态动力学关系。     

KINETICS OF FISCHER - TROPSCH SYNTHESIS OVER Fe - Cu - K CATALYST ( Ⅰ )KINETIC MODEL ON THE BASIS OF MECHANISM

由费托合成反应碳化物机理出发,考虑费托合成产物中烯烃再吸附对反应产物分布影响的事实,首次导出了费托合成反应动力学模型。该模型中由于引入烯烃再吸附项链增长几率不再是一个常数,因而更适合于解释铁基催化剂上非理想Anderson-Schulz-Flory产物分布.     

A MODEL OF DIFFUSION - REACTION PROCESSES OVER A CATALYST PELLET FOR NON - IDEAL REACTION SYSTEM (Ⅱ) NUMERICAL SIMULATION EXAMPLES

在本文(I)报建立的非理想尘气模型和非理想广义Stefan-Maxwell模型的基础上,结合常规反应-扩散模型,以氨和甲醇合成为例,研究了反应物系的非理想性对单颗粒催化剂效率因子模拟结果的影响.这些模拟结果之间以及甲醇合成模拟值与实验值之间的对比分析表明:描述这两个反应体系催化剂颗粒上的反应-扩散问题,必须考虑反应物系的非理想性.对于氨的合成,非理想费克模型已足以近似描述颗粒内的反应-扩散过程;但对于以CO/CO_2/H_2为原料的甲醇合成,采用非理想广义Stefa-Maxwell模型或非理想尘气模型比较适宜.     

STUDIES OF ADIABATIC FIXED-BED REACTORS (Ⅰ) IGNITION OF REACTORS

An approach for estimating the ignition temperature of adiabatic fixed-bed reactors is suggested. A phase plane of dimensionless temperature and dimensionless concentration is used to show both the ignition and extinction curves of a single catalyst pellet. The trajectory, i. e., the operating line of the reactor, which shows the progress of the chemical reaction, is always a straight line with a slope of —45°. Ignition occurs as the trajectory touches the ignition curve.A simple method is recommended to predict the critical gas inlet temperature which causes reactor ignition without recourse to determining the reaction kinetics. All reactions can be assumed to be of zeroorder.. This assumption introduces negligible error but considerably simplifies the experimental work.     

KINETICS OF METHANOL SYNTHESIS IN THE PRESENCE OF C301 Cu-BASED CATALYST (Ⅱ) EFFECTIVENESS FACTORS OF PARALLEL REACTIONS

For multiple reaction system of methanol synthesis in the presence of Cu-based catalyst, hydrogenation reactions of CO and CO_2 are selected as key reactions. A diffusion model, taking CO and CO_2 as key components, is presented for the calculation of the intraparticle effectiveness factors of the two parallel key reactions over C301 Cu-based catalyst. Numerical solutions of the effectiveness factors     

THE SWELLING BEHAVIOR OF (W/O)/W LIQUID SURFACTANT MEMBRANE (Ⅰ) ADSORPTION OF SURFACTANT AT THE INTERFACE AND THE SWELLING CAUSED BY EMULSIFICATION

The concept of effective concentration of surfaetant in membrane phase has been proposed,considering the high ad-sorption density of the surfactant at the droplet interfaces in LSM system.The effective concentration of surfactant,C_2,can be estimated by Eq.(7)—(9).The swelling caused by emulsification during the initial dispersion process was investigated.The swelling rate wasmeasured by a density method.A model for estimating the“Emulsification”swelling rate,F_(se),has been proposed,basedon a mechanism of swelling due to the entrainment of water resulted from the interracial turbulence and emulsification inthe initial dispersion process.It has been found that Eq.(26)gives excellent fit to the experimental data of Fujinawa,etal.and of the authors.     

KINETIC MODELING OF HYDROISOMERIZATION OF C\-8-AROMATICS(Ⅱ)MATHEMATICAL EXPRESSION OF RAY VECTOR AND ITS APPLICATION

1 .Introduction As deseribed in Part(I),Wei and Praterl’1,Prater et al.L,],and Silvestri et al.f3·‘1advaneed the rigorous analysis and the elegant framework of eomPlex reaetion system,Theirmethod,however,was aPPlied only to a few eases beeause of Iarge…     

POLYMERIZATION OF BUTADIENE IN TOLUENE WITH NICKEL(II) STEARATE-DIETHYL ALUMINUM CHLORIDE CATALYST†

A bench-scale batch reactor was used to study the polymerization of butadiene with nickel(II) stearate Et₂AlCl catalyst. In particular, the effects of moisture on polymerization were investigated. The initiation reaction is sensitive to temperature. At 0°C an induction period was observed, but at room temperature initiation can be assumed instantaneous. Water enhances catalytic reactivity, however at water concentrations greater than 10 mmol/L, termination reactions become significant. Maximum conversion is obtained in the 6 to 15 mmol/L range of water. The determining step for the molecular weight of polymer is the chain transfer to monomer. At low H₂O concentration the molecular weight increases with water concentration, however it becomes independent of water concentration at high moisture content. With the help of statistical analysis of the experimental data, a two-active-species model was developed to describe the kinetics of the system and to explain certain polymerization characteristics.