1 INTRODUCTION

  A general equation is proposed for predicting the liquid viscosities of petroleumfractions based on a generalized pseudocompound method in which pure hydrocarbons andundefined hydrocarbon mixtures or petroleum fractions are treated as a hypothetical puresubstance called pseudocompound which is characterized only by a boiling point and adensity . The equation is tested by using the liquid viscosities of the petroleumfractions of typical American crude oils and crude oils from major oil producing areas.Good agreement between the predicted and experimental viscosities for the petroleumfractions is obtained.     

Demulsification of Emulision Liquid Membrane by Wetting Coalescence Materials

Demulsification of emulsified watsr-in-oll droplets was worked out with the employment of wetting coalescence mtsrials. Demulsification is carried out in conventional stirted-colunm and packed-column, Among the four kinds of natural fibers and two kinds of inorganic materials tested, natural fiber A, originated from wood shavings was found to give the best performance of demulsifica-tion. The demulaification efficiency can exceed 96.5% when demulsification conditions are optimized. The packed-column showed much better performance both in terms of demulsification efficiency and repeated use of the recovered oll phase for extracting cadmium in simulated wastewater. Operating variables governing the demuliifieation efficiencv were inventigated.     

Demulsification of Emulision Liquid Membrane by Wetting Coalescence Materials

Demulsification of emulsified water-in-oil droplets was worked out with the employment of wetting coalescence materials. Demulsification is carried out in conventional stirred-column and packed-column. Among the four kinds of natural fibers and two kinds of inorganic materials tested, natural fiber A, originated from wood shavings was found to give the best performance of demulsification. The demulsification efficiency can exceed 96.5% when demulsification conditions are optimized. The packed-column showed much better performance both in terms of demulsification efficiency and repeated use of the recovered oil phase for extracting cadmium in simulated wastewater. Operating variables governing the demulsification efficiency were investigated.     

Theoretical study of methane adsorption on perfect and defective Ni(1 1 1) surfaces

We employ periodic density functional theory (DFT-GGA-PW91) calculations to study the adsorption of CH₄, on a perfect and defective (1 1 1) face of nickel, at a coverage of 0.25 monolayer (ML). As a surface defect, we consider a Ni adatom. We investigate systematically the site preference for CH₄, for various molecular orientations with 1, 2 or 3 H pointing toward the surface. Whatever the CH₄ adsorption site could be, the most stable configurations are obtained when 2 H atoms are directed to the surface. CH₄ stabilises weakly on the flat Ni surface, the adsorption energies being at best in the 50 meV range. However, beside a dominating physical interaction, some features are indicative of a chemical interaction through the Ni d-band. In presence of a Ni adatom, the chemical nature of the interaction manifests plainly, with sizeable adsorption energies up to 0.37 eV. The molecular restructuring and the mechanism of the interaction are examined.     

Interaction of water with the clean and oxygen pre-covered Ir(1 1 1) surface

Adsorption and reaction of water on the clean and oxygen modified Ir(1 1 1) single crystal surfaces have been studied using temperature programmed desorption (TPD) and molecular beam reactive scattering (MBRS) techniques under ultrahigh vacuum (UHV) conditions. Water dissociates on the clean Ir(1 1 1) surface with a probability (estimated based on production of hydrogen) which decreases from 0.016 to 0.004 ± 0.0015 with increasing water coverages from 0.34 to 2.59 monolayer. Scattering experiments performed at various surface temperatures in the limit of zero coverage yield water dissociation probabilities in the range of 0.0005–0.012 (300–900 K) with an uncertainty expressed as ±20% of the dissociation probability. The apparent activation energy for water dissociation on clean Ir(1 1 1) is estimated to be 170 ± 5 kJ/mol employing MBRS techniques, which probably cannot be applied to TPD measurements with higher water coverages. We speculate that water dissociation occurs on the defects of the Ir(1 1 1) surface. Using isotopically labeled reactants, a strong interaction between adsorbed water and oxygen was found on Ir(1 1 1), indicated by a new water desorption feature at 235 K and scrambled oxygen and water desorption products.     

Thermodynamic studies of phosphate adsorption on Pt(1 1 1) electrode surfaces in perchloric acid solutions

The thermodynamics of the so-called perfectly polarizable electrode was employed to analyze the total charge densities for a nearly defect-free Pt(1 1 1) electrode in a series of NaH₂PO₄ solutions with an excess of inert electrolyte (0.1 M HClO₄) at constant ionic strength and pH. Thermodynamic analysis using both electrode potential and charge density as independent electrical variables is described. The Gibbs excess, Gibbs energy of adsorption and charge numbers both at constant electrode potential and constant chemical potential for anion adsorption at the Pt(1 1 1) surface have been determined. The calculated electrosorption valencies and charge numbers at constant chemical potential are close to two electrons per adsorbed anion, suggesting that in the absence of co-adsorbed species, HPO₄²⁻ is the predominant adsorbed species. The maximum Gibbs excess of adsorbed hydrogenphosphate attains a value of ≈3.2 × 10¹⁴ ions cm⁻² which corresponds to a coverage of ≈0.22 ML.     

Comparison of H2 production from ethanol and ethylene glycol on M/Pt(1 1 1) (M = Ni, Fe, Ti) bimetallic surfaces

The reactions of ethylene glycol and ethanol have been studied on Fe/Pt(1 1 1) and Ti/Pt(1 1 1) bimetallic surfaces utilizing temperature programmed desorption (TPD). These results are compared to our previous studies on Ni/Pt(1 1 1) to illustrate the trend in the reforming activity on 3d-Pt bimetallic surfaces. The oxygenates decomposed on these surfaces to produce mainly H₂ and CO. The bimetallic surfaces were prepared by thermal evaporation of Fe or Ti onto Pt(1 1 1), using Auger electron spectroscopy (AES) to monitor surface compositions. Surfaces prepared by deposition of a monolayer of Fe or Ti on Pt(1 1 1), designated Fe–Pt–Pt(1 1 1) or Ti–Pt–Pt(1 1 1), displayed higher reforming activity for both ethylene glycol and ethanol than the corresponding subsurface monolayer Pt–Fe–Pt(1 1 1) and Pt–Ti–Pt(1 1 1) structures or clean Pt(1 1 1). The reforming yield increased as the surface d-band center, calculated from density functional theory (DFT), shifted closer to the Fermi level. The reforming selectivity of oxygenates, especially ethanol, began to decrease as the d-band center shifted closer to the Fermi level. Combining results in the current work with previous studies on Ni/Pt(1 1 1), a general criterion can be formulated for selecting 3d-Pt bimetallic surfaces with desirable reforming activity and selectivity.     

现代油水分离技术与原理

随着现代工业技术的不断发展,油水分离技术得到广泛应用。面对越来越困难的油水分离现状,基于不同工作原理,针对不同分离对象,多种油水分离技术随之诞生。通过对现代油水分离技术进行分类,深入分析了不同油水分离技术的工作原理,并结合原理列出相应的应用实例,评价了不同油水分离技术的分离效果,并根据油水分离的难度、使用对象、应用环境等因素的变化,建议采用相应的油水分离技术,实现经济高效地油水分离效果。最后,提出了现代油水分离技术中存在的问题和今后关于该研究发展的一些建议。     

物理法原油破乳研究进展

介绍了超声波破乳法、微波破乳法、电破乳法、研磨破乳法、膜破乳法等近几年较热门的油水乳状液物理破乳方法,综述了各方法的破乳机理和国内外研究进展,着重分析了超声波破乳法和微波破乳法的研究现状和发展方向,表明两者是最具前景的物理破乳法,指出未来原油破乳的发展趋势是高效、节能、环保。     

原油破乳研究进展

研发原油破乳技术是现代石油工业领域的重要研究方向之一。综述了原油破乳技术在近年所取得的研究进展,重点归纳和阐述了化学破乳、物理破乳和生物破乳法应用于原油破乳中的进展和各自的优势,并对发展工业规模原油破乳技术所需解决的主要问题和未来研究方向进行了探讨。     

Single domain epitaxial growth of yttria-stabilized zirconia on Si(1 1 1) substrate

Yttria-stabilized zirconia (YSZ) was epitaxially grown on both Si(0 0 1) and Si(1 1 1) substrates using a RF magnetron sputtering method. While YSZ(0 0 1) was grown on Si(0 0 1) with a cubic on cubic relation, YSZ(1 1 1) film on Si(1 1 1) with six-fold symmetry on surface showed two variants; cubic on cubic (type A) and 180° rotation about surface normal along [1 1 1] (type B). X-ray diffraction method confirmed single domain YSZ with type B structure when samples were prepared with the relatively slow deposition rate and low substrate temperature. Interestingly, in a reverse pairing of substrate and film, Si deposited on YSZ(1 1 1) substrates showed single domain with type A structure.     

Low‐firing and temperature stable microwave dielectric ceramics: Ba2LnV3O11 (Ln = Nd,Sm)

Low‐firing and temperature stable microwave dielectric ceramics of Ba₂LnV₃O₁₁ (Ln = Nd, Sm) were prepared by solid‐state reaction. X‐ray diffraction (XRD) and scanning electron microscopy (SEM) were used to investigate the phase purity, crystal structure, sintering behavior, and microstructure. The XRD patterns indicated that Ba₂LnV₃O₁₁ (Ln = Nd, Sm) ceramics belong to monoclinic crystal system with P2₁/c space group in the whole sintering temperature range (800°C ‐900°C). Both ceramics could be well densified at 880°C for 4 hours with relative densities higher than 96%. The Ba₂LnV₃O₁₁ (Ln = Nd, Sm) samples sintered at 880°C for 4 hours exhibited excellent microwave dielectric properties: ε_r = 12.05, Q × f = 23 010 GHz, τ_f = ?7.7 ppm/°C, and ε_r = 12.19, Q × f = 27 120 GHz, τ_f = ?16.2 ppm/°C, respectively. Besides, Ba₂LnV₃O₁₁ (Ln = Nd, Sm) ceramics could be well co‐fired with the silver electrode at 880°C.     

CHARACTERISTICS OF MICROMETER AND SUBMICROMETER SIZE O/W EMULSIONS PRODUCED BY RAMOND SUPERMIXER®

A novel motionless mixer named the Ramond Supermixer® (RSM®) was employed to produce O/W emulsions composed of micrometer and submicrometer-size droplets. Liquid paraffin as dispersed phase, aqueous sucrose solution as continuous phase, and anionic sodium dodecyl sulfate as emulsifying agent were used as the model emulsification system. Pressure drop, droplet size distribution, Sauter mean diameter (d₃₂), and geometric standard deviation of the droplet size distribution (σ_g) were investigated under the various combinations of process variables; superficial liquid velocity, number of mixing units, number of passages through RSM®, dispersed phase viscosity (η_d), continuous phase viscosity (η_c), and dispersed phase volume fraction. Different modes of droplet size variations with process variables were obtained, with respect to micrometer- and submicrometer-size ranges, and theoretical explanations are forwarded. For the micrometer-size range, maximum droplet diameter (d_max) was proportional to d₃₂. For the submicrometer-size range, d_max varied with d₃₂ in the range of 1.53-2.19-fold, and a correlation is proposed with K (=η_d/η_c); d₃₂ and σ_g were well correlated with the process variables. Furthermore, a semi-empirical mechanistic model was developed for the formation of droplets obtained under inertial sub-range to interpret the effect of process variables.     

微波破乳器的实验研究

对自制的800 W隧道式箱型微波破乳器进行了微波破乳实验研究. 详细考察了影响微波破乳器破乳效果的工艺参数,得出了最佳条件：流量70 L/h,温升速率16℃/min. 最佳实验条件下,含水50.0%的乳状液经微波破乳-离心分离后得到的离心油样含水率为2.2%. 循环连续破乳实验表明,含水率随有效停留时间的延长逐渐趋于稳定,采用多级串联的方法可以提高处理量,且可达到较好的破乳效果. 通过对微波破乳器的场强分布数值模拟,对比了有物料和无物料两种情况下微波破乳器的场强分布差异,为微波破乳器的进一步放大提供了依据.     

化学破乳特性与高分子聚合物破乳

乳浊液中含有大量的油类和表面活性剂,并以微细的颗粒液珠高度分散在水中,具有相当的稳定性。因此,破乳是处理乳化液废水的关键之所在。以阴离子表面活性剂作乳化剂的Ｏ／Ｗ型乳化液为研究对象,通过试验,分析乳化液的浓度、乳化液的ＰＨ值等因素对破乳的影响。并比较了聚合硫酸铝与聚合硫酸铁的破乳效果,分析了聚合硫酸铁的破乳机理及特性。说明聚合硫酸铁是一种新型高效的破乳剂,值得广泛推广,以利于更经济有效地治理乳化液     

超声与离心联用对乳状液破乳的研究

本文提出超声、离心联合作用于乳状液破乳的方法,采用正交实验研究离心时间、离心转速、超声破乳功率和超声破乳时间等因素对破乳效果的影响。研究表明,超声与离心联合作用可以使乳状液在较小的离心转速下,快速破乳。最佳工艺条件为：离心时间4min、离心转速1000r~min～、超声破乳功率40W、超声破乳时间2min,该条件下破乳率能达到97％。