用混合液相法合成的FeCl_3-GIC的膨胀特性

本文介绍了用混合液相法合成的FeCl_3-GIC的膨化实验,结果表明,将FeCI_3-GIC快速加热到800℃以上,可制备出100～300倍不同膨胀倍率的膨胀石墨。

用混合液相法合成的FeCl_3——GIC稳定性

通过对混合液相法合成的FeCl_3—GIC考察,经历某种环境后其(001)X射线衍射图中特征衍射峰强度比的变化,判断其阶结构的稳定性,通过测定差热效应(DTA)及热失重(TG)分析生成物的耐热温度表明:该法合成的FeCl_3—GIC结构稳定性优于双室法。

混合液相体系拉延油黏度关联与预测

制备一种牛顿型与非牛顿型的混合体系完全水溶性拉延油,并研究其黏度预测方法。在不同的体系温度下,以乙二醇为稀释剂,对拉延油高黏度和固态组分进行稀释调节,得到一种完全水溶性拉延油体系;将温度和稀释剂作为可调变量,利用线性和非线性最小二乘法对Eyring方程和Boltzmann方程进行联合回归计算,得到用于预测该类体系黏度的4参数模型以及模型参数与乙二醇稀释剂含量的关系式,其预测值与实验值平均相对百分误差仅为15.67%。该模型满足工程放大需求,可用于该混合体系的黏度预测。

计算机辅助求解混合固定相配比

随着色谱技术的迅速发展;许多新型的固定相出现,从而使气相色谱的应用范围日益扩大,使其成为近代重要的化学分析方法之一。目前在刑技化验中的应用也相当广泛。它主要用于分析混合物中的组分及含量,得到定量分析的结果,也为定性分析提供了极为有效的方法,并且具有分离度高、分析速度快、样品量小、检验灵敏度高、选择性好等特点。而在分析中起分离作用的固定相因品种繁多,特征相似的原因,往往很难找到一种固定液能把其中难分离的物质完全分离开,故我们采用性能不同的各单一固定液以适当的比例混合起来使用,作为理想极性和高效能、高选择性的混合固定相,用于分离和分析复杂的混合物。

激光散射图像可视化测量两相混合流场浓度分布

A mixing flow formed by a main tube flow and four side impinging jets was studied.The concentration distribution of the side flows was measured by using laser image visualization.The different flow patterns revealed the special pattern of concentration distributions in relation with the velocity ratio of jet flow to main flow.

Correlation of Vapour Liquid Equilibria of Binary Mixtures Using Artificial Neural Networks

In this paper, a back propagation artificial neural network （BP-ANN） model is presented for the simultaneous estimation of vapour liquid equilibria （VLE） of four binary systems viz chlorodifluoromethan-carbondioxide, trifluoromethan-carbondioxide, carbondisulfied-trifluoromethan and carbondisulfied-chlorodifluoromethan. VLE data of the systems were taken from the literature for wide ranges of temperature （222.04-343.23K） and pressure （0.105 to 7.46MPa）. BP-ANN trained by the Levenberg-Marquardt algorithm in the MATLAB neural network toolbox was used for building and optimizing the model. It is shown that the established model could estimate the VLE with satisfactory precision and accuracy for the four systems with the root mean square error in the range of 0.054-0.119. Predictions using BP-ANN were compared with the conventional Redlich-Kwang-Soave （RKS） equation of state, suggesting that BP-ANN has better ability in estimation as compared with the RKS equation （the root mean square error in the range of 0.115-0.1546）.

Power demand and mixing performance of coaxial mixers in a stirred tank with CMC solution

Experimental investigation was carried out in an elliptical based stirred tank with a diameter of 0.48 m to explore the power demand and mixing performance of coaxial mixers.Syrup and CMC solution(sodium carboxy methyl cellulose)were used as the Newtonian and non-Newtonian fluids,respectively.Four different coaxial mixers were combined with either CBY or Pfaudler impeller as the inner one,and anchor or helical ribbon(HR)as the outer one.Results show that Pfaudler-HR is the optimized combination among four coaxial mixers in this work,which provides the shortest mixing time given the same power consumption.Compared with the syrup solution,the increase of power input can make the mixing time decreasing more obviously in the CMC solution.The quantitative correlations for both syrup and CMC solutions were established to calculate the power draw and the mixing time of four coaxial mixers.

Phase Equilibrium Calculations in Mixtures Containing Caprolactam with a UNIFAC Model

An extended liquid-liquid equilibrium(LLE) UNIFAC model is proposed to describe phase equilibria of mixtures containing caprolactam.In this model,caprolactam is introduced as a new group.New group interaction parameters are calibrated from 156 sets of liquid-liquid equilibrium data.The present model gives satisfactory correlation and prediction in liquid-liquid equilibrium,including quaternary systems containing the mixed solvent of an alcohol and an alkane.The model can be applied to predict caprolactam solubility in water and benzene accurately.Freezing point and vapor-liquid equilibrium of binary systems containing caprolactam are also predicted with the extended LLE UNIFAC model.Satisfactory prediction results are obtained.

Simulation and Optimization for Thermally Coupled Distillation Using Artificial Neural Network and Genetic Algorithm

In this paper, a new approach using artificial neural network and genetic algorithm for the optimization of the thermally coupled distillation is presented. Mathematical model can be constructed with artificial neural network based on the simulation results with ASPEN PLUS. Modified genetic algorithm was used to optimize the model. With the proposed model and optimization arithmetic, mathematical model can be calculated, decision variables and target value can be reached automatically and quickly. A practical example is used to demonstrate the algorithm.

Comparison of the Reynolds-averaged Turbulence Models on Single Phase Flow Simulation in Agitated Extraction Columns

The flow field of liquid phase (water) of agitated extraction columns is simulated with the help of computational fluid dynamics (CFD). Four kinds of Reynolds-averaged turbulence models, i.e. the standard k-ε model, the RNG (renormalization group) k-s model, the realizable k-ε model and the Reynolds stress model, are compared in detail in order to judge which is the best model in terms of the accuracy, less CPU time and memory required. The performance of the realizable k-s model is obviously improved by reducing the model constant from C2 = 1.90 to C2 = 1.61. It is concluded that the improved realizable k-e model is the optimal model.

Influence of Nitric Acid Concentration on Characteristics of Olive Stone Based Activated Carbon

In this work we investigated the effect of nitric acid concentration on the pore structure,surface chemistry and liquid phase adsorption of olive stone based activated carbon prepared by mixing process using phosphoric acid and steam as activating agents.Chemicals and textural characterization show that the increase of HNO3concentration increases considerably the total acidic groups but decreases specific surface area and pore volume.The study of adsorption in aqueous solutions of two organics,phenol and methylene blue,on raw and oxidized activated carbon indicates that the treatment of mixed activated carbon with different concentrations of nitric acid improves the adsorbent capacity for methylene blue at HNO3concentrations less or equal to 2 mol·L 1,while it has a negative effect on phenol adsorption.

Dimension Reduction Method in Thermodynamics of Multireaction Systems(Ⅱ)Residual Properties,Property Changes of Mixing and Excess Properties Relations

Based on the fundamental thermodynamic principle the relationships of the residual properties, the property changes of mixing and the excess properties between the hypothetical solution of unreacted independent species and the equilibrated solution of actual species have been established. The hypothetical solution provides a way of reducing the dimensionality of problem and simplifying the analysis.

Toluene degradation by a water/silicone oil mixture for the design of two phase partitioning bioreactors

Toluene degradation performances were studied in a 10 L Two-Phase Partitioning Bioreactor(TPPB).The liquid phase consisted of a mixture of water and PDMS 50(Poly Di Methyl Siloxane,i.e.silicone oil,viscosity of 46 m Pa·s) in the volume ratio of 75%/25%.Two series of experiments were carried out:in the first,the reactor was sequentially supplied with toluene whereas in the second,toluene was continuously supplied.Activated sludge from the wastewater treatment plant of Beaurade(Rennes,France) was used at an initial concentration of 0.5 dry mass g·(mixture L)^(-1).The elimination capacity(EC) was investigated as well as the change in biomass concentration over time.Toluene biodegradation was very ef ficient(removal ef ficiency,RE=100%) for toluene flows ranging from 0.2 to 1.2 ml·h^(-1),corresponding to elimination capacities of up to 104 g·m^(-3)·h^(-1).For a toluene flow of 1.2 ml·h^(-1),the biomass concentration measured at the end of the experiment was 4.7 dry mass g·(mixture L)^(-1).The oxygen concentration in the liquid phase was clearly not a limiting factor in these operating conditions.Based on these results,an extrapolation leading to the design of a large-scale pilot TPPB can now be considered to study toluene degradation performances in industrial conditions.

Measurement and modelization of VLE of binary mixtures of propyl acetate,butyl acetate or isobutyl acetate with methanol at pressure of 0.6 MPa

The vapor-liquid equilibrium of binary mixtures of propyl acetate, butyl acetate and isobutyl acetate with meth- anol has been determined at a constant pressure of 0.6 MPa. Results have been modeled with the Peng-Robinson equation, a traditional cubic equation of state widely employed in chemical industries, as well as with the perturbed-chain statistical associating fluid PC-SAFT theory of Gross-Sadowski. By correlation of the binary inter- action parameters of these equations, the measured vapor-liquid equilibrium data can be accurately predicted. Thus, this work shows that these models are able to represent the experimental data for systems with associating comoounds via hydrogen bonding.

ELUTION OF TUNGSTEN BY SODIUM COMPOUNDS AND ACCELERATION EFFECTS OF COEXISTENT COUNTER IONS IN MIXED ELUANT

The elution of WO ions by NaOH. NaNO3 NaCl and NH4Cl on strong basicanion exchange resins in quaternary ammonium form I and the adsorption properties after elution were studied. In addition, the elution curse, the permeation curveand the exchange capacities of operation were presented. The eluate containingtungsten with high content and excessive eluant of low content were obtained by employing the process of eluting using mixed solution of NaCl and NaOH. It's possible to obtain Na2WO4. 2H2O with high purity by evaporating and crystallizing theeluate. The results of mixed elution showed that the diffusion coefficients of Cl-.OH- and WO ions in solution or exchange agent varied due to the coexistence ofcounter ions and then the exchange velocity of WO→Cl- and WOe→OH- wasaccelerated.

Combination of reversed phase liquid chromatography and zwitterion exchange-reversed phase-hydrophilic interaction mixed-mode liquid chromatography coupled with mass spectrometry for the analysis of antibiotics and their impurities

In this study, a system involving two-dimensional, column-switching high-performance liquid chromatography （HPLC） coupled with tandem mass spectrometry （LC-MS/MS） was developed and optimized for the analysis of antibiotics and their related substances. In the first-dimensional chromatography, the analytes were separated on a zwitterion exchange-reversed phase-hydrophitic interaction （ZIC-RP-HILIC） mixed-mode column coupled with tandem mass spectrometry （LC-MS/MS）. A commonly used reversed phase LC column was employed in the second-dimensional chromatography. The mobile phase for the ZIC-RP-HILIC mixed-mode chromatography consisted of a volatile buffer that was compatible with LC-MS/MS, which enhanced the efficiency of ionization for structure elucidation. The antibiotic impurities eluted in the ion-pairing reversed phase chromatography were directly characterized by the ZIC-RP-HILIC-MS system, and the orthogonal separation of ZIC-RP-HILIC mixed-mode chromatography and reversed phase LC provided extra confidence that no impurity was missed. The efficiency of this method was demonstrated in the analysis of penicillin V potassium, oxacillin sodium, ceftriaxone sodium, and their impurities. In addition, this method is convenient for impurity profiling of antibiotics, and may be used for the analysis of other pharmaceutical ingredients.

Nucleate Pool Boiling of Pure Liquids and Binary Mixtures: Part II-Analytical Model for Boiling Heat Transfer of Binary Mixtures on Smooth Tubes and Comparison of Analytical Models for both Pure Liquids and Binary Mixtures with Experimental Data

A combined physical model of bubble growth is proposed along with a corresponding bubble growth model for binary mixtures on smooth tubes. Using the general model of Wang et al.[1] and the bubble growth model for binary mixtures, an analytical model for nucleate pool boiling heat transfer of binary mixtures on smooth tubes is developed.In addition, nucleate pool boiling heat transfer of pure liquids and binary mixtures on a horizontal smooth tube was studied experimentally. The pure liquids and binary mixtures included water,methanol, ethanol, and their binary mixtures. The analytical models for both pure liquids and binary mixtures are in good agreement with the experimental data.

Control System for Low Pressure Gradient Mixer in High Performance Liquid Chromatograph

A control system used in high performance liquid chromatograph(HPLC) was described.The control system adopting low pressure gradient elution was tested with different initial and end volume fractions,and four types of gradient elution curves.The experimental results verified the theoretical analyses of the applied method.This self-designed control system can achieve approving accuracy,repeatability and low cost,which has a bright outlook for domestic applications.

Development on test equipment of coal slurry mixing tank

A coal slurry mixing tank is a key piece of equipment in the preparation of coal slurry for direct coal liquefaction.It is a gas-liquid-solid three-phase mixing device.Based on the performance of the existing coal slurry mixing equipment,a type of test equipment for horizontal continuous coal slurry preparation was developed,but to this point has limited research results.The test equipment consists of a mixing cylinder,mixer,stirring impeller and other components.Slurry mixing experiments were undertaken using the prototype,testing the performance of the device.A mathematical model was proposed specifically for the operation of a coal slurry mixing tank that is horizontally operated with high slurry concentration and rotary flow.The flow field in the horizontal coal mixing tank was simulated with the computational fluid dynamic (CFD) method.The experimental results match well with the CFD simulation results.Results show that the test device of a coal slurry mixing tank can be used to model the mixing of pulverized coal and the solvent oil.A strong correlation was obtained.