苯甲腈与茚二元体系的等压汽液平衡

纯茚在化学工业上应用广泛,而提取纯茚最重要的难题是分离杂质苯甲腈,因为苯甲腈的沸点与茚较接近。为了探究苯甲腈与茚的分离方法,用一个循环式汽液平衡装置测量了苯甲腈与茚在22.0、32.0和42.0 kPa下的等压汽液平衡数据。为了验证实验数据的可靠性,应用了面积检验法与微分检验法2种方法来对实验数据进行热力学一致性检验,结果表明实验数据能够通过一致性检验。然后应用了Wilson方程、NRTL方程以及UNIQUAC方程对实验数据进行拟合,得到了这3种模型的二元交互作用参数,结果表明这3种活度系数模型的拟合结果都与实验数据吻合较好。     

渗透汽化-酯化反应耦联膜过程动力学模型

建立了渗透汽化 -酯化反应耦联复合膜反应器过程动力学模型及测量复合膜渗透率的方法 .该动力学模型较系统地考虑了复合膜反应器中可能影响酯化反应化学平衡移动的各种因素 .研究结果表明 ,模型的模拟结果能很好地与实验结果相吻合 .     

The development and evaluation of a theory of thixotropic behavior

The consistency decay of a thixotropic fluid under sustained shear is similar in many respects to a first order — second order reversible chemical reaction and has been described in terms of an analogous kinetic model. The data necessary for an experimental evaluation of the theoretical model were obtained through an analysis of the Theological behavior of Pembina Crude Oil. These data were then effectively correlated in terms of the theoretical expression.     

The electrochemical recovery of iron in a two-compartment batch electrochemical reactor

A model has been developed for a two-compartment batch electrochemical reactor in which simultaneous iron deposition and hydrogen evolution occur at the cathode, the anodic reaction being the production of hydrogen ions. The model incorporates ionic diffusivities through the diaphragm and a composite kinetic parameter for the cathodic reactions. In order to apply the model to data from a small batch reactor, the diffusivities have been obtained under conditions in which hydrogen alone is evolved at the cathode. The value of the kinetic parameter has been chosen to provide the best agreement between the model predictions and the experimental results. Satisfactory predictions of the current efficiency for iron deposition and the final concentrations in the reactor has been obtained, the largest discrepancies between predicted and actual concentrations being at high anolyte hydrogen ion concentrations. Reasons for these discrepancies are discussed.     

德士古渣油气化炉的数值模拟

渣油在德士古气化炉中发生非常复杂的不完全燃烧反应,它生成了工业生产合成氨所需的原料气。文中建立了这一过程的数值模拟模型,采用κ-εRNG模型来模拟湍流流动,简化的PDF模型来模拟湍流燃烧过程,辐射传热采用离散坐标模型,得到符合生产实验的燃料模型。     

Dynamic modelling of consecutive reactions: Application to the acrylonitrile amination

When dealing with optimal control problems to maximize the selectivity of reactions for fine chemical synthesis, representative kinetic and thermodynamic models should be available. While literature appears to be very extensive on theoretical approaches to solve the problem, examples presenting complete models of chemical transformations are scarce. This paper presents the identification of consecutive reactions carried out in a batch reactor. Material and energy balances, satisfying dynamical state evolutions in the temperature range 20-60°C are deduced, for concentrations of acrylonitrile ranging up to 1.6 kmol·m^?3. The stoichiometric network is simplified into two reactions, one reversible and one irreversible. Reaction enthalpies are measured from isothermal runs conducted in the RC1 heat-flow calorimeter from Mettler Toledo.     

New methods of determination of kinetic parameters of theoretical models from experimental data

Integral and integro-differential methods have been developed for determining unknown characteristics of a kinetic experiment, including the rates of chemical reactions, the initial concentrations of substances, and Michaelis constants. These methods are applicable to a wide class of reactions and are most efficient when the system of differential equations considered is linear with respect to all, or a group of, unknown parameters. For an open multienzyme system obeying the Michaelis-Menten system of equations that is nonlinear in unknown parameters, it is demonstrated how the initial system of equations can be transformed into a new system that is linear with respect to new variables functionally depending on the initial parameters. A method has been developed for reformulating the initial nonlinear problem of determining the unknown parameters into a linear one. In this method, the initial problem is immersed into the more general problem of identifying the coefficients of a differential equation such that the initial formula is one of the solutions of this equation. This method can also be used to determine kinetic parameters of theoretical models that are formulated in terms of both concentrations and activities. A method of complete identification of chemical kinetic problems has been analyzed for the case of the incomplete observability of some components of the reaction, and it has been concluded that the kinetics of the substrate and intermediates in a multistep consecutive reaction can be qualitatively and quantitatively reconstructed by monitoring its product provided that the product concentration is precisely determined.     

脉动进料气液旋流分离器分离性能分析

为提高钻井液振动筛的气、固、液分离能力,一种以振动筛形成的脉动真空与压缩空气注入相结合的固液分离钻井方法被提出,在此基础上出现了一种采用脉动进料边界的旋流器。为分析旋流器的气液分离性能,需要探究其脉动进料条件下的最佳气液分离效率及其影响参数。为此,采用Fluent对稳定、脉动进料状态下不同结构参数的旋流分离器进行流动模拟,通过UDF函数设置脉动进料边界,并分析效率曲线得到脉动进料状态下分离器的最优参数。结果表明,脉动进料状态下的流场可以较好地实现稳定;采用频率为0.4 Hz的正弦脉冲进料气液分离效率最高,可达85.5%;在脉动进料状态下,其脉动不连续性会导致流场湍动能变大,径向压力降梯度降低,切向速度峰值降低。     

新型高效规整填料的性能研究

为了获得可靠的设计依据,实验在不同回流比条件下,用环己烷-庚烷和庚烷-甲苯2种二元测试物系对CDG1700Y和CDG2500Y型金属丝网规整填料的流体力学性能和传质性能进行了考察。实验结果表明,这2种填料的压降随着液体流量的增大而增大,单位填料层高度的HETP变化趋势则相反;CDG1700Y和CDG2500Y型填料具有较高的理论板数,且CDG1700Y型填料具有较大的操作弹性。在SRP(II)模型的基础上,获得了实验室条件下传质单元高度的经验关联式,其计算值与实验结果吻合较好,可以为化学交换法分离硼同位素的工业化提供理论指导。     

Hierarchical multiscale model-based design of experiments, catalysts, and reactors for fuel processing

In this paper a hierarchical multiscale simulation framework is outlined and experimental data injection into this framework is discussed. Specifically, we discuss multiscale model-based design of experiments to optimize the chemical information content of a detailed reaction mechanism in order to improve the fidelity and accuracy of reaction models. Extension of this framework to product (catalyst) design is briefly touched upon. Furthermore, we illustrate the use of such detailed and reduced kinetic models in reactor optimization as an example toward more conventional process design. It is proposed that hierarchical multiscale modeling offers a systematic framework for identification of the important scale(s) and model(s) where one should focus research efforts on. The ammonia decomposition on ruthenium to produce hydrogen and the water–gas shift reactions on platinum for converting syngas to hydrogen serve as illustrative fuel processing examples of various topics. The former is used to illustrate hierarchical multiscale model development and model-based parameter estimation as well as product engineering. The latter is employed to demonstrate model reduction and process optimization. Finally, opportunities for process design and control in portable microchemical devices (lab-on-a chip) for power generation are discussed.     

催化剂填料催化乙酸甲酯水解的动力学研究

采用间歇搅拌釜反应器在40~55的温度范围内以强酸性催化剂填料为催化剂研究了乙酸甲酯的水解动力学规律。实验在原料水与乙酸甲酯的摩尔配比0.5:1~2:1范围内考察了低水浓度时的动力学结果,并采用了较小的粉状催化剂颗粒和较高的搅拌速度以消除内外扩散阻力。实验结果分别用均相动力学模型和基于Langmuir- Hinshelwood 理论的非均相动力学模型进行拟合,得到了两者的模型参数。统计检验发现在水浓度不太高的条件下基于单点吸附理论的表面反应是最关键的控制步骤,此时用非均相动力学方程来拟合实验数据比较准确,而传统上采用的均相动力学方程拟合精度较差,只有在水浓度很高的条件下才能适用。     

Solubility determination and thermodynamic modeling of bis-2-hydroxyethyl terephthalate (BHET) in different solvents

Studies on the degradation process of waste polyethylene terephthalate (PET) have become increasingly mature, but there are relatively few studies on the separation of degradation products. The products contain many components and the separation of which is difficult. Therefore, the study on phase equilibrium thermodynamics of bis-2-hydroxyethyl terephthalate (BHET) is of great theoretical significance and practical value to provide basic data for the BHET crystallization separation. In this work, the degraded products were purified and characterized. The solubility of BHET in methanol, ethanol, ethylene glycol, water and the mixture of ethylene glycol + water were determined by static method. The experimental results were correlated with different models, such as ideal solution (IS) model, λh equation, Apelblat equation and NRTL model. Based on the van't Hoff equation, the mixing Gibbs energy, enthalpy and entropy were calculated. From this work, the basic data which can be used to guide the crystallization process of BHET were obtained, including solubility data, correlation model and thermodynamic properties.     

Kinetics of fast reactions in condensed systems: Some recent results (an autoreview)

In 1972, Alexander Merzhanov formulated theoretical backgrounds for a new line of research in chemical physics termed non-isothermal chemical kinetics (NIK) and outlined fundamental advantages of NIK methods in comparison with those of classical chemical kinetics. Since then, the NIK methods and approaches have been widely used in the basic and applied research in the field of chemistry and chemical engineering. We used the NIK methods to study the kinetics of fast reactions in condensed energetic materials (EM). Overviewed are the kinetic data on high-temperature decomposition of some homogeneous and heterogeneous EMs used in modern rocket and aviation engineering. Discussed are some recent data on the kinetics of fast high-temperature reactions taking place during electrothermal explosion under static conditions obtained with an ETA-100 instrument. New kinetic data on the reactions under static conditions and upon high- and low-speed impact are analyzed and compared.     

USE OF FINITE PROPAGATION VELOCITY IN THE SOLUTION OF INTERFACE MASS TRANSFER PROBLEMS†

A number of theories have been proposed to explain and interpret mass transfer processes at interfaces. Most of these models are based on solutions of Fick's Law of diffusion to describe the transfer process. There are evidences, however, both experimental and theoretical, which show that this fundamental law has shortcomings. An objection to the classical error-function solution of the diffusion problem is the physically unrealistic predicted instantaneous response at every position in the system to a step change. In addition, mass transfer rate given by such a solution approaches infinity as time approaches zero. Inclusion of finite velocity of propagation in the governing differential equation overcomes both the theoretical objections to the classical solution. This concept is utilized in predicting the concentration profile and mass transfer rates in systems with zero and first order chemical reactions.     

USE OF FINITE PROPAGATION VELOCITY IN THE SOLUTION OF INTERFACE MASS TRANSFER PROBLEMS†

A number of theories have been proposed to explain and interpret mass transfer processes at interfaces. Most of these models are based on solutions of Fick's Law of diffusion to describe the transfer process. There are evidences, however, both experimental and theoretical, which show that this fundamental law has shortcomings. An objection to the classical error-function solution of the diffusion problem is the physically unrealistic predicted instantaneous response at every position in the system to a step change. In addition, mass transfer rate given by such a solution approaches infinity as time approaches zero. Inclusion of finite velocity of propagation in the governing differential equation overcomes both the theoretical objections to the classical solution. This concept is utilized in predicting the concentration profile and mass transfer rates in systems with zero and first order chemical reactions.