复吹转炉钢-渣间容量传质系数的水-油模型

在熔池直径 880mm、深 2 5 8mm的冷态模型中 ,利用水模拟钢水、机油模拟渣、苯甲酸模拟钢 渣间传输物质来研究熔池直径 5 2 85mm、深 15 4 5mm的复吹转炉吹炼工艺参数对钢 渣间容量传质系数的影响。结果表明 ,枪位 35 0mm ,顶吹流量 117m3 /h ,底吹流量 1 6 8m3 /h至 2 36m3 /h时 ,传输物质苯甲酸的容量传质系数变化最显著 ,在采用枪位 35 0mm ,顶吹流量 14 0m3 /h ,底吹流量 1 6 8m3 /h ,底枪布置方式为 8孔对称布置在 0 6 6直径的圆上时 ,传输物质的容量传质系数最大。

Applicability of Fractal Models in Estimating Soil Water Retention Characteristics from Particle-Size Distribution Data

Soil water retention characteristics are the key information required in hydrological modeling. Frac-tal models provide a practical alternative for indirectly estimating soil water retention characteristics fromparticle-size distribution data. Predictive capabilities of three fractal models, i.e, Tyler-Wheatcraft model,Rieu-Sposito model, and Brooks-Corey model, were fully evaluated in this work using experimental datafrom an international database and literature. Particle-size distribution data were firstly interpolated into20 classes using a van Genuchten-type equation. Fractal dimensions of the tortuous pore wall and the poresurface were then calculated from the detailed particle-size distribution and incorporated as a parameter infractal water retention models. Comparisons between measured and model-estimated water retention cha-racteristics indicated that these three models were applicable to relatively different soil textures and pressurehead ranges. Tyler-Wheatcraft and Brooks-Corey models led to reasonable agreements for both coarse- andmedium-textured soils, while the latter showed applicability to a broader texture range. In contrast, Rieu-Sposito model was more suitable for fine-textured soils. Fractal models produced a better estimation of watercontents at low pressure heads than at high pressure heads.

Critical parameters of horizontal well influenced by semi-permeable barrier in bottom water reservoir

It is well-known that barriers have a significant impact on the production performance of horizontal wells developed in a bottom water drive reservoir. In most cases, reservoir barriers are semi-permeable. Based on previous research on impermeable reservoir barrier, a mathematical flow model was derived for a horizontal well of a bottom water drive reservoir with a semi-permeable barrier. Besides, analytical equations were also presented to calculate critical parameters, such as production rate,pressure and potential difference. The effects of barrier, well and reservoir parameters on our model results were further investigated.The results show that the larger the barrier size is or the higher the barrier location is, the higher the critical production rate and potential difference of a horizontal well are. When the barrier permeability equals the formation permeability or the barrier width equals zero, the critical production rates converge to the values same to that of the case with no barrier. When the barrier permeability equals zero, the problem is regarded as a case of impermeable barrier. This model can be applied to predicting horizontal wells' critical production parameters in reservoirs with semi-permeable barriers.

Numerical Simulation of Enhanced Oil-Water Separation in a Three-Stage Double-Stirring Extraction Tank

Numerical simulation of enhanced fluid flow characteristics in a three-stage double-stirring extraction tank was conducted with the coupling of an Eulerian multiphase flow model and a Morsi-Alexander interphase drag force model. Results show that the addition of a stirring device into the settler can efficiently reduce the volume fraction of out-of-phase impurity in the outlet, and accelerate the settling separation of oil-water mixture. Such addition can also effectively break down the oil-water-wrapped liquid droplets coming from the mixer, inhibit reflux from the outlet, and improve the oil-water separation. The addition of a stirring device induces ignorable power consumption compared with that by the mixer, and can thus facilitate the commercialized promotion of this novel equipment.

B-SPLINE-BASED SVM MODEL AND ITS APPLICATIONS TO OIL WATER-FLOODED STATUS IDENTIFICATION

A method of B-spline transform for signal feature extraction is developed. With the B-spline, the log-signal space is mapped into the vector space. An efficient algorithm based on Support Vector Machine (SVM ) to automatically identify the water-flooded status of oil-saturated stratum is described. The experiments show that this algorithm can improve the performances for the identification and the generalization in the case of a limited set of samples.

Assessing the kinetic model of hydro-distillation and chemical composition ofAquilaria malaccensis leaves essential oil

This study aimed to model the kinetic of hydro-distillation of Aquilaria malaccensis leaves oil in order to understand and optimize the extraction process. In addition, this study, for the first time, aimed to identify the chemical compositions of the A. rnalaccensis leave-oil. By assessing both first-order kinetic model and the model of simultaneous washing and diffusion, the result indicated that the model of simultaneous washing and diffusion better describes the hydro-distillation mechanism of the essential oil from A. rnalaccensis leaves. The optimum time, solid to liquid ratio, and the heating power for extracting the highest amount of essential oil were found to be around 3 h, 1：10 （g. ml-1）, and 300 W respectively. Yellow essential oil with a strong smell and a yield of 0.05 v/w was extracted by hydro-distillation Clevenger apparatus. Chemical compounds of the essential oil were analyzed using gas chromatography-mass spectroscopy （GC/MS）, which resulted in identification of 42 compounds that constitute 93% of essential oil. Among the identified components, Pentadecanal （32.082%）, 9-Octadecenal, （Z） （15.894%）, and Tetradecanal （6.927%） were the major compounds. Considering the fact that all the identified major components possess pesticidal properties, A. malaccensis leaves can be regarded as a promising natural source for producing pesticides.

Proposed Models for Subcritical Water Extraction of Essential Oils

Mechanisms that control the extraction rate of essential oil from Zataria multiflora Boiss. (Z. multiflora) with subcritical water (SW) were studied. The extraction curves at different solvent flow rates were used to deter-mine whether the extractions were limited primarily by the near equilibrium partitioning of the analyte between the matrix and solvent (i.e. partitioning thermodynamics) or by the rates of analyte desorption from the matrix (i.e. ki-netics). Four simple models have been applied to describe the extraction profiles obtained with SW: (1) a model based solely on the thermodynamic distribution coefficient KD, which assumes that analyte desorption from the ma-trix is rapid compared to elution; (2) one-site kinetic model, which assumes that the extraction rate is limited by the analyte desorption rate from the matrix, and is not limited by the thermodynamic (KD) partitioning that occurs dur-ing elution; (3) two-site kinetic model and (4) external mass transfer resistance model. For SW extraction, the thermodynamic elution of analytes from the matrix was the prevailing mechanism as evidenced by the fact that ex-traction rates increased proportionally with the SW flow rate. This was also confirmed by the fact that simple re-moval calculations based on determined KD (for major essential oil compounds) gave good fits to experimental data for flow rates from 1 to 4 ml·min-1. The results suggested that the overall extraction mechanism was influenced by solute partitioning equilibrium with external mass transfer through liquid film.