浅谈玻璃纤维行业的设备与技术管理

本文分析了我国玻纤行业的管量现状,结合重庆市玻璃纤维厂对设备与技术管理的成功经验,对玻纤行业的设备和技术管理进行了探讨,具有现实的指导意义和参考价值.     

浅谈玻璃纤维行业的物流管理

本文分析了玻璃纤维行业的物流现状和特点,指出现代物流对玻璃纤维行业的发展产生积极影响.     

Calculation of heterogeneous detonation taking into account deformation and breakdown of fuel droplets

Combustion, Explosion, and Shock Waves -     

Mathematical modeling of pigment dispersion taking into account the full agglomerate particle size distribution

The purpose of this work is to develop a mathematical model that can quantify the dispersion of pigments, with a focus on the mechanical breakage of pigment agglomerates. The underlying physical mechanism was assumed to be surface erosion of spherical pigment agglomerates. The full agglomerate particle size distribution was simulated. Data from two previous experimental investigations were used for model validation. The first concerns two different yellow organic pigments dispersed in nitrocellulose/ethanol vehicles in a ball mill and the second a red organic pigment dispersed in a solvent-based acrylic vehicle in a three-roll mill. When the linear rate of agglomerate surface erosion was taken to be proportional to the external agglomerate surface area, simulations of the volume-moment mean diameter over time were in good quantitative agreement with experimental data for all three pigments. The only adjustable parameter used was an apparent rate constant for the linear agglomerate erosion rate. Model simulations, at selected values of time, for the full agglomerate particle size distribution were in good qualitative agreement with the measured values. A quantitative match of the experimental particle size distributions could be obtained using time-dependent fragment distributions, but this resulted in a very slight improvement in the simulated transient mean diameter only. The model provides a mechanistic understanding of the agglomerate breakage process that can be used, e.g., in the development of novel dispersion principles and for analysis of dispersion failures. The general applicability of the model, beyond the three pigments considered, needs to be confirmed.     

Measurement and modeling of axial distribution of adsorbent particles in expanded bed: taking into account the particle density difference

Based on the previous work (Yun et al., Chem. Eng. Sci. 59 (2004) 449-457), after the analysis of adsorbent structure, bed expansion and in-bed fluid hydrodynamics, a model was developed to describe the axial variations of the mean particle size and local bed voidage for adsorbents with a broad size distribution and different densities in expanded bed. In the model, the different-size particles were assumed to have different densities while the equal-size particles have the same density. Particle densities were described by a function that considered two parts of each particle: the resin-core part consisting of resin and inert core-particulates, and the thin resin film part without inert core-particulates. With UpFront FastLine SP adsorbents as interest test particles, the particle size and local voidage changes with bed height were measured in a 20 mm I.D. column and then predicted by the model. It was shown that the mean particle size decreased, while the local bed voidage increased with increase of bed height. These trends are similar to those for particles with a broad normal size distribution and nearly uniform density. More obvious increase trends of voidage with increase of bed height exist in expanded beds with UpFront FastLine SP particles compared with those of Streamline particles. The present model gave a good prediction of bed expansion, the mean particle sizes and local voidages in most parts of bed compared with experimental data.     

Unsteady transformations in thin two-component films: A model taking into account random particle size distribution

Detailed 2D analysis have demonstrated that an increase in the variance (var) of size distribution can be expected to result in changing a mode of quasi-heterogeneous combustion in heterogeneous mixtures to a relay-race regime. A two-stage combustion wave formed in the range of intermediate scale parameters was found to depend on var. The development of unsteady combustion modes is governed by the appearance of hot spots formed behind the combustion zone. Strong retardation of chemical reaction by coarser particles extends the range of quasi-homogeneous combustion. Formulated were conditions for the two-stage combustion under consideration. The influence of heat exchange between reaction zones on wave stability were studied by using approximate analytical methods and numeric experiments. The dynamics of two-stage combustion is governed by a temperature of the leading reaction and afterburning kinetics.     

Applications of nanotechnology in oil and gas industry: Progress and perspective

Nanotechnology has been successfully implemented in many applications, such as nanoelectronics, nanobiomedicine, and nanodevices. However, this technology has rarely been applied to the oil and gas industry, especially in upstream exploration and production. The oil and gas industry needs to improve oil recovery and exploit unconventional resources. The cost of research and oil production is under immense pressure, and it is becoming more difficult to justify such investment when the crude oil price is weak and depressed. There is a widespread belief that nanotechnology may be exploited to develop novel nanomaterials with enhanced performance to combat these technological barriers. Increasing funding resources from governmental and global oil industry have been allocated to exploration, drilling, production, refining, and wastewater treatment. For example, nanosensors allow for precise measurement of reservoir conditions. Nanofluids prepared using functional nanomaterials may exhibit better performance in oil production processes, and nanocatalysts have improved the efficiency in oil refining and petrochemical processes. Nanomembranes enhance oil, water and gas separation, oil and gas purification, and the removal of impurities from wastewater. Functional nanomaterials can play an important role in the production of smart, reliable, and more durable equipment. In this review paper, we summarize the research progress and prospective applications of nanotechnology and nanomaterials in the oil and gas industry.     

Improving k La determination in fungal fermentation,taking into account electrode response time

An alternative way for determining the oxygen mass transfer coefficient, k_La, based upon the traditional dynamic method, is proposed. The oxygen material balance equation in the liquid phase is integrated after insertion of the oxygen probe response time (first order type), and k_La values are determined by employing Marquardt's algorithm, considering as a weighting factor the model's sensitivity with respect to k_La. Bench‐scale fermentations of Aspergillus awamori, performed under different agitation (300–700 rpm) and aeration conditions (0.2–0.6 vvm), were utilized for calculating k_La values (0.0283–0.0874 s⁻¹), employing three methods: two so‐called traditional, the gas balancing and the dynamic methods, and the one proposed here. The latter method is shown to be as reliable as the aforementioned methods but is easier to apply when the oxygen level in the reactor is above the critical value. © 2000 Society of Chemical Industry     

Study of gas-liquid stirred reactor stability taking into account the temperature influence on gas solubility

The paper is devoted to the dynamic behavior and stability of gas-liquid stirred reactor taking into account the temperature influence on gas solubility. Since the rate of gas-liquid processes is very sensitive to concentration of gas reactant dissolved in liquid, even weak fluctuations of temperature can significantly influence on process pass. There are two cases of temperature influence on gas solubility are possible: (1) the solubility decreases with increasing temperature; (2) the solubility grows with increasing temperature. The first case is typical for majority of gases. The second case occurs more rarely but has a great practical importance. It takes place, for example, for the hydrogenation of many compounds in organic solvents (such as benzene, toluene, isopropyl alcohol and others). A model of gas-liquid process has been developed to demonstrate the stability of gas-liquid reactor. It has been shown that the gas solubility behavior has an influence on the form of heat production curve and therefore on the multiplicity of the steady states. The areas of multiplicity and limit cycles were found and the phenomenon of hysteresis in the reactor was shown. A criterion to determine whether the multiplicity is possible under the given conditions was found. By means of an analysis of a mathematical model the stability of steady states of the reactor was studied.     

Thermophoretic deposition efficiency in a cylindrical tube taking into account developing flow at the entrance region

This study investigates the effect of developing flow in a circular tube on the thermophoretic particle deposition efficiency using the critical trajectory method numerically. When both flow and temperature are fully developed (combined fully developed), present results agree with previous theories for the long tube where the flow temperature approaches that of the wall. When the flow is fully developed and temperature is developing, it is found that only near the thermal entrance region (or temperature jump region) of the tube the deposition efficiency is slightly higher than the combined fully developed case (flow and temperature), while the deposition efficiency remains the same for the long tube. When both flow and temperature are developing (or combined developing), the deposition efficiency is about twice that of the combined fully developed case for the long tube and is much higher near the entrance of the tube. Non-dimensional equations are developed empirically to predict the thermophoretic deposition efficiency in combined developing and combined fully developed cases under laminar flow conditions.     

Numerical simulation of gasless combustion taking into account the heterogeneity of the structure and the temperature dependence of diffusion

This paper presents the results of numerical simulation of self-propagating high-temperature synthesis based on a model that takes into account the heterogeneity of the mixture of the reacting powders and the temperature-dependent mutual diffusion. Dependences of the velocity of the combustion front on the size of the averaged element of the heterogeneous structure are obtained for different diffusion activation energies. It is found that as the activation energy of diffusion increases, an oscillatory regime of propagation of the combustion front is established. The boundary of the transition from the steady-state propagation of the combustion front to the oscillatory regime is determined.     

Modeling of mass transfer in apparatuses with a stationary granular bed taking into account the phase temperature difference

In this paper, we consider the mass-transfer process in apparatuses with a fixed granular bed. The literature data were analyzed and it was shown that the main driving force of the mass transfer between the outer surface of the grains and the gas flow at a significant difference between the temperature of the phases is the difference of the reactants partial pressures. A comparison of the results of calculating the mass-transfer coefficient using the most popular in the domestic and foreign literature empirical correlations of Sherwood number on the Reynolds and Schmidt (diffusion Prandtl number) numbers was performed. It has been shown that the calculation results do not differ from each other despite the difference in the calculation formulas. The methodology of calculating the mass-transfer process in the two-phase model of a fixed catalyst bed has been provided.     

Mathematical modeling of the motion of an air suspension taking into account nonequilibrium melting (crystallization)

Within the framework of the mechanics of heterogeneous media undergoing phase transformations, we propose a mathematical model for describing the flow of a mixture of gas and liquid (solid) metal particles. We consider the difference between the velocities and temperatures of the phases and the nonequilibrium nature of the phase transition. As an example, we solve the problem of the structure of a shock wave in an air suspension of melting particles. We isolate the conditions determining the monotonic and nonmonotonic temperature behavior of the mixture. We present numerical data illustrating the determined types of motion of the gas suspension.Institute of Theoretical and Applied Mechanics, Siberian Branch, Russian Academy of Sciences, Novosibirsk 630090. Translated from Fizika Goreniya i Vzryva, Vol. 30, No. 4, pp. 91–99, July–August, 1994.     

纳米技术在橡胶工业中应用的新进展

简述了聚合物纳米复合材料的制备，详述了纳米增强橡胶复合材料、功能性纳米橡胶复合材料以及纳米技术改性着色剂技术的研究开发进展，并探讨了橡胶纳米复合材料的发展方向。     

Advanced development in upstream of petroleum industry using nanotechnology

Nowadays, energy supply is one of the most important issues due to limitation of oil, gas and coal sources. Because of rapid population, civilization and energy consumption growth, the improved technologies to make optimal use of the sources, solving related problems and finding new energy sources are important. More than 10 years ago, nanotechnology as one of the most important technologies has also been applied to progress in the oil and gas industry (upstream, midstream and downstream). The experience of these years has shown that application of nanotechnology in the oil industry improves the exploration of crude oil and natural gas (underground or deep water), drilling and bringing the crude oil or raw natural gas to the surface, as well as transportation, storage, processing and purifying methods. Nanoparticles with high specific surface area, pore volume and small size show unique physical and chemical properties, which could be applied in several applications. In this regard, many researchers have been focused on various nanoparticles for upstream industries and studied their potential in oil exploration, drilling, production and enhanced oil recovery (EOR). Also, in downstream and midstream which involve refining of crude oil, processing and purifying of raw natural gas, transportation and storage of crude or refined petroleum products, the nanomaterials have been used to improve the quality of oil and make it appropriate for the environment. Lowering sulfur gasoline, enhancing the octane number and coating the transportation system are among the goals that have been achieved successfully using nanotechnology. In this work, various types of nanoparticles such as metallic, metal oxide, hybrid nanoparticles, carbon nanomaterials, nano-composites and their applications in oil upstream industry are reviewed. Also, their usage in different types of oil upstream processes is discussed.     

Epoxy/amine systems with monodisperse modifiers: thermodynamic analysis of the phase separation process taking the polymer polydispersity into account

Phase separation during polymerisation was studied by taking into account in the thermodynamic analysis the generated distribution of polymer species. A model system consisting of a diepoxide based on diglycidylether of bisphenol A, a diamine and castor oil as modifier was considered. One-and two-step polymerisation processes were simulated (in the two-step process a first step was carried out with an epoxy excess up to a particular conversion, stoichiometry was balanced and the reaction continued in a second step). A thermodynamic analysis for a monodisperse modifier-epoxy/amine system was performed taking the polydispersity of the polymer into account. It was shown that the cloud point conversion was decreased when the polymerisation was carried out in two steps. This effect was enhanced for lower stoichiometric ratios (higher epoxy excesses) and higher epoxy conversions in the first step. The dispersed phase became richer in low molecular weight species than the continuous one. In particular both monomers increased their concentration in the dispersed phase.