固体颗粒对油水界面性质及乳状液稳定性的影响

采用界面张力仪、表面粘弹性仪和Zeta电位仪,研究了固体颗粒对胜利原油油水界面性质及乳状液稳定性的影响。结果表明,固体颗粒的存在使得油水界面张力及界面剪切粘度增加,O/W型乳状液的稳定性增加,而且随固体颗粒浓度增加,乳状液稳定性增强;在0.21~500μm范围内,固体颗粒粒径减小,其与原油形成的O/W乳状液稳定性增强,乳状液内部油珠表面Zeta电位负值增加。     

矿粉微粒制备Pickering乳液降低原油乳状液黏度的研究

采用一种价廉易得的S115型矿渣微粉和羧乙基纤维素、十二烷基苯磺酸钠协同稳定航煤-水乳状液,制备水包油型Pickering乳状液,室温下30 d后乳化指数大于95%,表明其具有很好的稳定性。采用粒度分析、Zeta电位、界面张力及流变性能测试等方法对稳定机理进行了研究,结果表明,矿渣颗粒吸附于油水界面与十二烷基苯磺酸钠协同形成单层或多层颗粒膜,增加了Zeta电位和黏弹性,降低了油水界面张力,导致其稳定性增加。将制备的Pickering乳状液用于稠油乳状液的降黏,结果比不含固体颗粒的普通乳状液具有更好的降黏效果。     

蜡含量对稠油水包油乳状液性质的影响

对于含蜡稠油水包油乳状液性质影响的研究多集中于胶质、沥青质、固体颗粒等因素上,对于蜡组分对水包油乳状液性质的影响研究较少。本文以某油田稠油和石蜡配制的不同含蜡量的乳状液为研究对象,利用Zeta电位粒度仪、界面张力仪以及流变仪等分析了不同含蜡量对乳状液Zeta电位、界面张粒径大小、流变性、粘温特性、表观粘度的影响。研究表明,在一定温度、一定含蜡量下水包油乳状液Zeta电位下降,表面张力降低,粒径减小,稳定性增强,对乳状液流变性不会产生明显影响。温度变化对含蜡稠油水包油乳状液性质有重要影响。     

胜利原油乳状液中固体颗粒特性及其脱除技术

随着我国原油储量逐渐减少,原油开采技术逐渐成熟,在开采过程中乳状液所含的固体微粒随之增加。以胜利油田滨南采油区块682原油乳状液为研究对象,应用显微镜、纳米粒度仪和光谱分析仪,表征胜利乳状液中固体颗粒的特征,揭示原油乳状液中固体颗粒形成机制和物理特性。此外,根据分析结果,将乳状液脱除固体微粒的离心法,与复配脱固乳状液相结合,研究了高效固体颗粒脱除技术。     

水包油乳状液稳定性影响因素分析研究综述

管道运输是油品运输的重要方式之一,所以稠油乳状液在运输过程中的稳定性对运输效率起到决定性作用。不同类型的表面活性剂、界面张力、油水比、乳化温度、分散相粒径、化学添加剂、界面电荷等对稠油乳状液稳定性有着不同的影响,而影响水包油乳状液稳定性的主要因素是稠油乳状液分散性粒径的大小、界面张力和油水界面膜的性质。分析了平均粒径、界面张力和油水界面膜性质对水包油型稠油乳状液的稳定性影响,探究了使其稳定的机理和影响平均粒径、界面张力、油水界面膜性质的因素,并对水包油乳状液稳定性研究的发展前景进行展望。     

孤岛原油乳状液稳定性影响因素研究

通过乳状液稳定性实验考察了孤岛原油乳状液稳定性影响因素。结果表明,低剪切作用下,部分水解聚丙烯酰胺(HPAM)与原油作用1d和54d,所测得其浓相体积分数很快接近零,即HPAM与原油所形成的乳状液稳定性较低。而当溶液中存在50μg/g固体颗粒蒙脱土时,测得其与原油作用1d和54d后的浓相体积分数都约0.08。当溶液中同时含有固体颗粒与HPAM时,测得其与原油作用后所形成的乳状液浓相体积分数很快达到零,固体颗粒与HPAM的协同作用对原油乳状液稳定性有较大影响。另外,随着盐浓度、温度的增加,孤岛原油所形成的乳状液稳定性降低。在30000r/min高速剪切作用下,测得聚合物、固体颗粒模拟水体系与原油间所形成的乳状液浓相体积分数约为0.3,可形成较稳定的乳状液。     

不同类型的固体颗粒与石油磺酸盐协同稳定乳状液的研究

选用不同类型的固体颗粒与石油磺盐(DPS)复配,形成不同类型的油水乳状液,对二者协同作用稳定乳液的机理进行了探讨。研究表明,亲水性纳米二氧化硅与DPS组合不能形成稳定的乳液;氧化铝改性的纳米二氧化硅、疏水性纳米二氧化硅、碳纳米管、膨润土均可以与DPS发生协同作用,形成稳定的Pickering乳状液,这是因为这些固体颗粒满足以下特征之一:表面带有正电荷或者具有较长的疏水链;固体颗粒的形貌为层状结构,且具有一定的吸附性;具有C纳米管的管状结构,且侧壁含有高度离域的π电子。上述研究也为该体系在化学驱中的应用奠定了基础。     

甜菜碱表活剂性能评价

通过界面张力仪、TURBISCANLAB稳定分析仪及微分干涉显微镜对甜菜碱表面活性剂及其聚表体系的稳定性进行研究。研究表明:原油乳状液稳定系数与聚合物浓度成反相关;多重光散射原理的基础上应用TURBISCANLAB稳定分析仪从动态上反映乳状液颗粒从稳定到失稳的过程;结合微分干涉显微及驱油实验提出了一种综合评价乳状液稳定性的方法。     

乳化作用及其在化妆品工业的应用(Ⅱ)

乳状液是热力学不稳定的体系。本文系统地介绍了乳状液各种不稳定性的表现，包括分层、絮凝、聚结、破乳、变型和Ostwald熟化。较详细地讨论了影响乳状液稳定性的主要因素，如界面膜的物理性质、抗聚结作用的静电和空间势垒、固体粒子对乳状液的稳定作用等。     

纳米颗粒表面特性对可逆乳状液的影响

可逆乳状液可集中不同液体形式的优势,但其由表面活性剂稳定时不耐高温,考虑用纳米颗粒与表面活性剂复配制备可逆乳状液。本文研究纳米颗粒表面特性对可逆乳状液的影响,结果表明,纳米二氧化硅颗粒的表面性质对"纳米二氧化硅与表面活性剂复合制备的乳状液"的性质有决定性作用,亲水性纳米二氧化硅与表面活性剂复配稳定的乳状液不能实现pH响应可逆转化,亲油性纳米二氧化硅与表面活性剂复配稳定的乳状液能实现pH响应的可逆转化。     

抗高温碱腐蚀的新型高铬铸造不锈钢的研制

设计了用于含有固相颗粒的高温碱介质的新型高铬铸造不锈钢的组织及化学成分。采用金相显微镜和Ｘ射线衍射的方法分析了新型钢的组织，通过多种腐蚀试验方法研究了该钢的腐蚀与磨蚀行为。试验结果表明，新型高铬铸造不锈钢在含有固相颗粒的高温碱苛刻介质中，具有良好的耐蚀性及抗磨蚀、点蚀与晶间腐蚀性能。此外，该钢还具有良好的综合力学性能与铸造性能。     

Phase hold-up and critical fluidization velocity in a three-phase inverse fluidized bed

We studied the hydrodynamic characteristics of a three-phase inverse fluidized bed made of a transparent acrylic column of 0.115 m inner diameter and 2 m heights. Air, water and polyethylene particles were used as the gas, liquid and solid phase, respectively. We used both hydrophobic low density polyethylene (LDPE) and hydrophilic LDPE as solid phase, and distilled water as liquid phase, and filtered air as gas phase. The LDPE was chemically treated by chlorosulfonic acid to change the surface property from hydrophobic to hydrophilic. We tried to solely investigate the effect of the surface hydrophilicity of polymeric particles on the phase holdup and the critical fluidization velocity of three-phase inverse fluidization. Thus, we measured the static pressure and eventually observed critical fluidization velocity. Critical fluidization velocity became smaller in case of using MDPE hydrophobic particles than LDPE hydrophilic particles. This was thought to be due to the retardation of rising bubbles near hydrophobic particles and, subsequently, the increase of gas hold-up.     

Micro-scale fluid model for drying of highly porous particle aggregates

A discrete three-dimensional model for the fluid flow and phase transition at the microscopic scale during convective drying of highly porous particle aggregates has been developed. The phase distributions are described by time-dependent cell volume fractions on a stationary cubic mesh. The solid phase volume fractions are computed from an arbitrary collection of spherical primary particles generated by gravitational deposition using the discrete element method. The volume of fluid method is used to track the liquid–gas interface over time. Local evaporation rates are computed from a finite difference solution of a vapor diffusion problem in the gas phase, and the liquid–gas interface dynamics is described by volume-conserving mean curvature flow, with an additional equilibrium contact angle condition along the three-phase contact lines. The evolution of the liquid distribution over time for different wetting properties of the solid surface as well as binary liquid bridges between solid particles are presented.     

Double emulsions of water-in-oil-in-water stabilized by α-form fat microcrystals. Part 1: Selection of emulsifiers and fat microcrystalline particles

Double emulsions are commonly stabilized by monomeric and/or polymeric emulsifiers. Pickering stabilization by solid particles such as colloidal microcrystalline cellulose has been mentioned only once as a possible technique to stabilize the external interface of the water-in-oil-in-water emulsion. No further work was carried out exploring this option. The present study shows that solid microcrystalline fat particles of α-form are capable of adsorbing at the water-oil interface and, together with other hydrophobic emulsifiers, can stabilize water-in-oil (W/O) emulsions. The crystals must be submicron in size in order to effectively adsorb and arrange at the interface. Large crystals do not fit and were found to flocculate as free crystals in the continuous oil phase. The α-form crystals can be obtained by flash-cooling saturated triglycerides in vegetable oils in the presence of emulsifiers, such as polyglycerol polyricinoleate (PGPR), that stabilize the dispersion and serve as α-tending crystal structure modifiers. It was assumed that PGPR also serves as a cross-linker or bridge between the crystalline fat particles and the water, and facilitates the anchoring of the fat particles in the oil phase in one direction while dangling itself in the water phase. The double emulsion droplets prepared with these W/O emulsions are relatively large in size (6–18 μm), but stable to coalescence. The marker (NaCl) does not seem to release with time, suggesting that the fat particles form microcapsules on the water interface, totally sealing the water from releasing its addenda. The systems seem to have a significant potential for food emulsions.     

纳米无机粒子选择性分布与迁移对聚合物共混物形态与性能的影响

综述了纳米无机粒子在聚合物合金中选择性分布的影响因素及纳米无机粒子在聚合物中分散的重要性,重点从相行为、相形态、力学性能、电学性能、流变行为、结晶和熔融行为以及光学性能等方面总结了近年来纳米无机粒子在聚合物共混物中的选择性分布与迁移对以聚合物共混物为基体的纳米复合材料的形态和性能的影响。特别强调了如何利用热力学和动力学因素调控纳米无机粒子在聚合物合金中的分布。     

The morphology and mechanical properties of PP/EPDM/nano-CaCO3 composites: effect of initial mixing state

Polypropylene (PP) was blended with ethylene–propylene–diene terpolymer (EPDM) and calcium carbonate nanoparticles (nano-CaCO₃), where all the components were in different initial mixing states, i.e., all in solid (solid blending composite), nano-CaCO₃ and EPDM first forming solid master batch, then being mixed with solid PP (master batch blend composite) and all in melt (melt blending composite). The phase morphology, especially the distribution of nano-CaCO₃, and mechanical properties of the resultant composites and their dependence on the initial mixing states of the components were studied systematically. Morphological observation revealed that essentially different from the respectively dispersed morphology of nano-CaCO₃ particles and EPDM phase in the PP matrix in the solid blending composite, abundant well-dispersed nano-CaCO₃ particles concentrating around EPDM phase in the melt blending composite. Due to the cavitation initiated by the debonding and the fibrillation present at interface as a result of well-dispersed nano-CaCO₃ particles, its impact strength was pronouncedly enhanced, increasing 280 % compared to PP/EPDM composite. Our work paves the way to obtain high-performance PP composites.     

水平窄矩形通道内液固两相的流动特性

液固两相输运研究主要集中于圆管,窄矩形通道内液固两相水平流动特性和固相扩散特性的研究鲜见报道。在12mm高的水平窄矩形通道内,采用实验研究和计算流体力学-离散单元法（CFD-DEM）数值模拟相结合的方法研究了玻璃珠-水液固两相流动,揭示了压力梯度特性、固相流动特性及其统计学特性、固相扩散特性变化规律。结果表明：在固相运动过程中,形成稀密两相共存的流动结构,密相在水平方向上被加速且向上运动;随着固相浓度增加,固相沿垂向的分布更加均匀,但固相速度非对称分布增强;固相垂向扩散强度随固相浓度增加而减弱。沿垂向将流道分为3个区域：近壁区、颗粒高频碰撞区和颗粒稀疏区。在近壁区,黏性底层-湍流层交界面与颗粒相互作用并将颗粒向流道中心挤压,导致沿流向的固相速度分量和固相体积分散波动较大;在颗粒高频碰撞区,在垂直方向上颗粒无序运动造成其垂向速度分量波动比近壁区和颗粒稀疏区的大;沿流向的固相速度分量和固相体积分数标准差值在整个颗粒高频碰撞区内保持在较小的变化范围,然后在颗粒稀疏区内迅速降低为零。     

Chemical absorption into concentrated slurry: Absorptions of carbon dioxide and sulfur dioxide into aqueous concentrated slurries of calcium hydroxide

The absorption of sulfur dioxide and carbon dioxide into aqueous calcium hydroxide slurries were performed using a stirred tank with a plane gas-liquid interface at 308 K. The absorption rates were found to be lower than those predicted by assuming that the solid particles are uniformly suspending in the liquid-film as well as the bulk liquid phase.It might be due to the possibility that there is no particle suspending in the vicinity of the interface. The process of gas absorption with reaction in the slurry was formulated by film-theory model incorporating the presence of an inert region in which there is no particle. The observed absorption rates of sulfur dioxide and carbon dioxide were successfully predicted by the proposed model.     

Effect of spent grains on flow regime transition in bubble column

It is well known that two main flow regimes are present in bubble columns, being the evaluation of transition between homogeneous and heterogeneous regimes of crucial importance for reactor design. For air–water systems, several models have been satisfactorily proposed to explain this phenomenon. However when gas–liquid–solids systems are considered, solid particles influence on regime transition is not yet clear, in spite of the amount of research developed over the past years.The objective of this work is to evaluate the effect of a specific solid phase – spent grains – on homogeneous regime stability and regime transition. Spent grains are cellulose-based particles that have been used to immobilize cells on biotechnology process. These particles are wettable and have a density close to water and its influence on bubble column reactors is particularly important in order to establish the limits were both regimes prevail.A cylindrical Plexiglax BC of 18 L volume was used with air, water and spent grains at different concentrations (0–20% (wt._{WET BASIS}/vol.)) as gas, liquid and solid phases. Regime transition was determined according to the drift-flux and slip speed concept.It was found that at studied concentrations of spent grains, critical gas hold-up decreases as solids concentration increases. At the highest solids concentration and lowest gas flow rates no fluidization of the solid phase was observed. It is believed that the critical hold-up decrease was mainly due to bubble coalescence, as larger bubbles were observed when heterogeneous regime was present. This coalescence may be caused by the non-uniform distribution of solid phase on the column and the interaction of spent grains with bubbles in the liquid–gas interface     

第三相的加入对气液传质过程的影响

系统地介绍了气液传质过程中,固体小颗粒或第二分散液相(有机相)所形成的第三相的加入对传质过程的影响.分别论述了在不同的气-液接触器(搅拌釜、鼓泡塔)中,固体小颗粒和第二分散液相的加入对体系的传质系数、传质速率及界面面积等的影响,叙述并讨论了传质机理及模型的最新进展.