A predictive kinetic model of sulfur release from coal

The aim of this paper is to present a predictive kinetic model of the release of sulfur compounds from coal. The model first characterizes the relative amount of the different forms of sulfur components. Inorganic (pyritic and sulfates) and organic sulfur (aliphatic, aromatic and thiophenic) are estimated quite simply on the basis of a wide range of elemental coal compositions available in the literature. Sulfur compounds are released in the gas phase mainly as H₂S and S components in the tar fraction. A sulfur fraction also remains in the residual char. The kinetic model, with the related rate parameters, is validated through comparison with experimental data from the literature. The agreement is satisfactory, even though further experimental and theoretical investigation would be useful to improve the reliability of this kinetic model still further.     

基于共存理论的二元系强电解质水溶液质量作用浓度通用热力学模型

利用离子-分子共存理论建立了可计算强电解质水溶液组元质量作用浓度的热力学通用模型. 以KCl-H2O, CsCl-H2O, NaCl-H2O及BaCl2-H2O二元系为示例,计算了上述4个二元系在温度为298.15 K、质量摩尔浓度在0.2 mol/kg到饱和浓度范围内的组元质量作用浓度. 热力学模型计算的以纯物质为标准态、以摩尔分数为浓度单位的组元质量作用浓度经过转换后,与文献报道的以无限稀为标准态、以质量摩尔浓度为浓度单位的组元活度可良好吻合. 这说明本工作建立的强电解质水溶液的质量作用浓度热力学模型可用于预测组元活度,基于强电解质水溶液中存在离子和分子结构的推断是合理的,质量作用浓度在计算的组元浓度范围内遵守质量作用定律.     

盈德清华炉水煤浆气化工艺的影响因素研究

以过程模拟软件为工具,通过合理的简化与假设,建立了以氧气为气化剂的水煤浆气流床煤气化的研究模型,模拟计算了盈德清华炉的水煤浆气化过程,分析了煤中碳含量、灰分含量、水煤浆质量分数、操作温度、水冷壁副产蒸汽量等因素对比煤耗、比氧耗、合成气产量、合成气中各气体组分含量的影响。模型计算结果与生产实际运行数据对比表明,该模型能较好地反映运行工厂的实际生产情况。利用经过生产实际运行数据修正的研究模型,可研究煤质组成、煤浆质量分数、操作温度、水冷壁副产蒸汽量等因素对主要气化工艺指标的影响。     

葡萄糖／脯氨酸Maillard反应模型及其产物的烟草加香评价

为开发特色烟用香原料,针对葡萄糖／脯氨酸Maillard反应模型体系,通过正交试验考察了反应时间、反应温度、体系pH和溶刹中乙醇体积分数对产物的紫外可见吸收、挥发性成分及烟草加香效果的影响,确定了适宜的反应条件。结果表明：各因素对产物紫外可见l吸收的影响大小依次为pH〉反应时间〉反应温度〉乙醇体积分数;GC—MS鉴定出33种挥发性成分,多种成分对香气有重要贡献;感官评价表明反应温度105℃、反应时间4h、pH10、乙醇体积分数40％的条件下生成的产物具有良好的烟草加香效果,香气量、香气质较好,杂气、刺激性小。研究表明,葡萄糖／脯氨酸Maillard反应产物具有良好的烟草加香应用价值。     

RFCC化学汽提过程的模拟研究

采用欧拉模型耦合反应模型对重油催化裂化环流汽提段内的化学汽提过程进行了模拟研究,考察了汽提段内的颗粒体积分数分布、油气组分分布以及高温再生剂的加入对汽提效果的影响,并与实验值进行了对比。结果表明模拟结果与实验数据基本吻合。模拟得到的汽提段底部颗粒体积分数约为0.3～0.45,而在上部迅速降低至0.2左右。由汽提段底部向上,气体组分和汽油组分含量（质量分数）显著增加,在床层上部达到了20%左右,重组分含量显著降低至床层上部的约30%,而柴油组分含量保持在30%左右变化不大。随着再生剂的加入,汽提段顶部气体组分和汽油组分的含量增加,重组分和柴油组分的含量减小,当再生剂加入量为60%时,重组分含量降至18%。     

Comprehensive method of investigating polyeutectic systems

The technological constraints on the deposition of the main components from the first anthracene fraction by solidification are analyzed by a comprehensive method of investigating polyeutectic systems. The constraints on solidification for the extraction of the main components in the fraction are identified.     

Sintering of Inhomogeneous Binary Powder Mixtures

A geometric model for the sintering of inhomogeneous, binary powder mixtures having a large size ratio is presented. The model is demonstrated for a hypothetical mixture in which the heterogeneity is described by a normal distribution function. The model is demonstrated for the case of the fine fraction sintering only and for the case of both components sintering. Relative to the prediction for the homogeneous mixture, shrinkage is observed to be either "enhanced,""retarded," or the same, depending on the compositional limits of heterogeneity and the level of sintering.     

超临界CO_2萃取铁观音茶叶香气成分

分别采用索氏萃取(SE)、同时蒸馏萃取(SDE)和超临界CO2萃取(SFE)方法提取铁观音的香气成分。用GC/MS分析比较了萃取物中香气成分的组成及质量分数。SDE获得了最多的香气组分,而SFE得到的主要香气成分质量分数和萃取率最高。进一步考察了SFE的压力、温度及夹带剂对主要香气成分的萃取率及质量分数的影响,结果表明随着压力升高香气成分的萃取率及质量分数均升高。而当温度和夹带剂中乙醇质量比为45℃和5%时,总香气成分的萃取率最高,且主要香气成分的质量分数比未添加夹带剂时提高达几十倍,与SFE所得萃取物在香烟中品香评吸的结论完全吻合。     

甲醇-乙酸-丙酸多元体系汽液平衡

用新型泵式沸点仪测定了在100kPa下甲醇-乙酸、甲醇-丙酸、乙酸-丙酸3个二元体系以及甲醇-乙酸-丙酸三元系在不同液相组成时的沸点,并用间接法T-p-x(温度、压力和液相摩尔分数)推算了3个二元体系的汽相平衡组成。3个二元体系活度系数分别用Wilson模型、NRTL模型、Margules模型和van Laar模型进行关联,用最小二乘法求出了它们的液相活度系数模型参数,同时,用这些模型参数来计算它们的汽相摩尔分数。所得的液相活度系数来计算3个二元体系的过量吉布斯自由能函数,且所研究的所有体系中各组分之间不存在共沸点。用3个二元体系Wilson模型参数对所测的三元体系数据进行关联,建立该系统汽液平衡的热力学模型并计算平衡时的汽相摩尔分数和泡点温度。由面积积分法检验这些模型参数计算的3个二元体系相平衡数据,得到很好的热力学一致性。     

A model of the electrical conductivity of anthracite and graphite dispersions in electrolytes

The electrical conductivity of anthracite and graphite dispersions in the solutions of potassium chloride was measured. A linear increase in the electrical conductivity as a function of the weight fraction of a dispersed phase was observed in the region of electrolyte concentrations of 0.0005?C0.01 M. In 0.1 M solutions, the dependence of the electrical conductivity of a suspension on the weight fraction of a dispersed phase (0.1?C15 wt %) decreased with the subsequent increase. A model was proposed for the electrical conductivity of anthracite and graphite dispersions in electrolytes; in accordance with this model, charge transfer due to the electrophoretic mobility of particles makes the main contribution to an increase in the electrical conductivity. Different electrical conductivity components (specific surface conductivity) calculated from the Bikerman equation and based on the model proposed were compared.     

Binding properties of coal-tar pitches in relation to nuclear magnetic resonance spectra

The yield of quinoline-insoluble portion from pitches correlates well with the aromatic hydrogen content of the carbon disulphide-soluble fraction scaled up by proportion to the whole pitch, which therefore by implication is an indication of the binding properties. The chemical shifts are explained with reasonable accuracy on the basis of the ring-current, model of Pople applied to fluorene and acenaphthene, which form the chief components of the pitches normally encountered.     

Identification of Carbonyl Compounds in Transesterified Fats Detection in Milk Fat

The non-glyceridic fraction of fats transesterified in the presence of Na-K alloy, and the unsaponifiable fraction of these fats were studied by chromatographic methods. α-Diketones derived from the fatty acids components have been found to be the main by-products of the non-glyceridic fraction, mono-ketones being also present as minor products. These α-dike tones are destroyed during alkaline hydrolysis and when the unsaponifiable fraction is studied, monoketones are found as the main components. On the basis of these findings a method for detecting transesterified fats in natural fats, particularly in milk fat, is proposed.     

Prediction of CO2-Oil Minimum Miscibility Pressure Using Soft Computing Methods

Searching for computational approaches for determination of the minimum miscibility pressure (MMP) is highly requested during the miscible gas injection process. New models, namely, the stochastic gradient boosting (SGB) algorithm and two distinct hybrid artificial neural network (ANN) models were used to predict CO₂ MMP as a function of reservoir temperature, mole percent of volatile oil components, mole percent of intermediate oil components, molecular weight of pentane-plus fraction in the oil phase, mole percentage of CO₂ in injected gas, volatile components, and intermediate components in the injected gas based on 144 published data points. The SGB model was found to provide the better performance. The reservoir temperature turned out to be the most important factor.     

Polymorphic changes in mixtures of confectionery fats

The polymorphic behavior of mixtures of cocoa butter and high melting cocoa butter fraction with three types of confectionery fats and mixtures of the confectionery fats with each other were investigated with a differential scanning calorimeter. The confectionery fats were an interesterified-fractionated fat, a hydrogenated-fractionated fat, and a lauric acid fat. The lowered melting point observed in mixtures of confectionery fats with cocoa butter or cocoa butter fraction was related to the proportion of triglycerides dissimilar to the major components in cocoa butter and cocoa butter fraction contained in a particular confectionery fat. The hydrogenated-fractionated fat contained ca. two-thirds 2-oleodisaturated triglycerides similar to the major components of cocoa butter; the interesterified-fractionated fat, ca. one-third 2-oleodisaturated triglycerides. The lauric acid fat contained virtually no triglycerides similar to cocoa butter. The series of mixtures of confectionery fats with cocoa butter and cocoa butter fraction that had the least melting point lowering were those that contained 25% hydrogenated-fractionated fat; the ones that had the greatest lowering of melting point were those that contained 25% lauric acid fat. Mixtures of confectionery fats with cocoa butter possessed considerable amounts of low melting components, whereas similar mixtures with cocoa butter fraction exhibited a narrower melting range and possessed few low melting components. The more highly crystalline confectionery fats can accommodate the addition of fats containing some low melting components. The most compatible of the series of mixtures of confectionery fats with each other was the mixture of interesterified-fractionated fat containing 25% hydrogenated fractionated fat; the least compatible, hydrogenated fractionated fat containing 25% lauric acid fat. Presented at the AOCS Meeting, Mexico City, April 1974.     

Effects of polar groups of polymer matrix on reinforcement-matrix interaction in kevlar fiber-reinforced composites

In order to investigate the interaction between the polar groups of reinforcement and matrix in polymer composite, mechanical properties were studied for the Kevlar fiber-reinforced composites (Kevlar is a registered trademark of E. I. duPont de Nemours Co. Inc.), in which the kind and fraction of polar components in matrix were varied using blended polymers. For the composites comprised of polymethyl methacrylate and poly(hydroxypropyl ether of bisphenol A) as the matrix, a subtransition, which can be ascribed to the interphase formed on the reinforcement surface by a strong interaction between reinforcement and matrix, appears at a temperature above the primary transition on the E″ versus temperature curves. Such a subtransition is obscured or diminished accompanying the decrease in fraction of the polar components in the matrix. The fiber efficiency factors for strength are also decreased with a decrease in the fraction of the polar components. These results imply that the reinforcement-matrix interaction is affected depending on the fraction of the polar components in matrix. For the composite comprised of blending the two polar components as the matrix, each component can contribute to the interaction with the reinforcement. The results obtained from the Fourier transform infrared spectroscopy on the matrix polymer-coated Kevlar cloth do not contradict those obtained by studying the mechanical properties.     

Brassica campestris var. Span: I. Fractionation of Rapeseed oil by molecular distillation and adsorption chromatography

Procedures for the large scale isolation of pure triglycerides and fractions rich in nontriglyceride components from Span rapeseed oil are described. Fractionation ofBrassica campestris var. Span rapeseed oil by molecular distillation yielded 4 triglyceride fractions, all of which contained traces of sterol esters. An additional triglyceride fraction rich in free and esterified sterols and other volatile components was obtained from the oil. Separation by adsorption chromatography of Span rapeseed oil yielded three fractions: A) a pure triglyceride fraction; B) a triglyceride fraction rich in sterol esters; and C) another fraction containing free sterols and other polar components. Contribution no. 559 Animal Research Institute.     

Modeling the melt transesterification of polycarbonate

A mathematical model of the melt transesterification of polycarbonate in a mechanically agitated reactor system without a distillation column is proposed. Penetration theory is applied to the mass‐transfer operation of volatile components in both a transesterification reactor and a polymerization reactor by simplification of the flow pattern. The applicability of the proposed model is examined by the comparison of its predictions with experimental data of the collected condensate of volatile components, the end‐group ratio, and the weight fraction distribution of the resulting polymer. The end‐group ratios have been determined by carbon‐13 nuclear magnetic resonance spectroscopy, and the distribution of weight fractions has been measured by gel permeation chromatography. It is shown that the model's predictions are very consistent with the experimental data. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

ECT imaging of three-phase fluidized bed based on three-phase capacitance model

In this work, the electrical capacitance tomography (ECT) with neural network multi-criteria optimization image reconstruction technique (NN-MOIRT), early developed by the authors, is applied to imaging bubble column and three-phase fluidized bed systems in the real time manner. Air, norpar (paraffin) and glass-beads are used as the gas, liquid, and solid phases, respectively. A three-phase capacitance model coupled with a two-region model is proposed to attain the gas holdup and the solids fraction from the permittivity maps of the three-phase system. The two-region model assumes that the solids fraction in the emulsion phase in the no bubble region is the same as in the bubble region. The three-phase capacitance model combines series and parallel capacitance connections among gas, liquid and solid components to relate the three-phase permittivity to each phase holdup. A direct image calculation to obtain the gas holdup from the permittivity map of the three-phase system is also performed by determining the permittivity threshold for the gas bubbles. Comparisons of the gas holdup obtained by ECT with that obtained from liquid head measurement showed a good agreement, validating the applicability of the model and its associated image calculation.     

煤气化废水中有机物交互作用及响应面优化研究

基于三维响应面方法,采用Design Expert软件,研究了以苯酚、乙酸、萘为代表的模型化合物单组分、双组分及三组分有机物在热降解过程中的交互作用。采用响应面模型对热降解处理煤气化废水的COD降解率、NH₃-N降解率进行预测,分析了反应条件(温度、氧浓度、反应时间)对COD降解率、NH₃-N降解率的影响。研究表明,不同模型化合物降解由易到难为乙酸、苯酚、萘,萘对COD的降解具有抑制作用,而乙酸可以促进苯酚的降解;温度对煤气化废水COD降解率、NH₃-N降解率的影响最为显著。     

精馏过程的新逐板计算法——(I)多元精馏过程的操作型计算

本文应用迭代数学理论提出了一个适用于理想系统和与之相近的轻烃系统的多元精馏操作型计算的新逐板计算法.它将整个迭代过程重组为总量迭代和比值迭代二个平行的迭代过程,获得了快速且均匀的收敛性.本法为直接设计型计算法打下了必要基础.