Micro–Nano Water Film Enabled High‑Performance Interfacial Solar Evaporation

Interfacial solar evaporation holds great promise to address the freshwater shortage.However,most interfacial solar evaporators are always filled with water throughout the evaporation process,thus bringing unavoidable heat loss.Herein,we propose a novel interfacial evaporation structure based on the micro–nano water film,which demonstrates significantly improved evaporation performance,as experimentally verified by polypyrrole-and polydopamine-coated polydimethylsiloxane sponge.The 2D evaporator based on the as-prepared sponge realizes an enhanced evaporation rate of 2.18 kg m^(−2)h^(−1)under 1 sun by fine-tuning the interfacial micro–nano water film.Then,a homemade device with an enhanced condensation function is engineered for outdoor clean water production.Throughout a continuous test for 40 days,this device demonstrates a high water production rate(WPR)of 15.9–19.4 kg kW^(−1)h^(−1)m^(−2).Based on the outdoor outcomes,we further establish a multi-objective model to assess the global WPR.It is predicted that a 1 m^(2)device can produce at most 7.8 kg of clean water per day,which could meet the daily drinking water needs of 3 people.Finally,this technology could greatly alleviate the current water and energy crisis through further large-scale applications.

Quantitative research of the liquid film characteristics in upward vertical gas, oil and water flows

The study of liquid film characteristics in multiphase flow is a very important research topic, however,the characteristics of the liquid film around Taylor bubble structure in gas, oil and water three-phase flow are not clear. In the present study, a novel liquid film sensor is applied to measure the distributed signals of the liquid film in three-phase flow. Based on the liquid film signals, the liquid film characteristics including the structural characteristics and the nonlinear dynamics characteristics in three-phase flows are investigated for the first time. The structural characteristics including the proportion, the appearance frequency and the thickness of the liquid film are obtained and the influences of the liquid and gas superficial velocities and the oil content on them are investigated. To investigate the nonlinear dynamics characteristics of the liquid film with the changing flow conditions, the entropy analysis is introduced to successfully uncover and quantify the dynamic complexity of the liquid film behavior.

Effect of Alkali on Daqing Crude Oil/Water Interfacial Properties

Alkaline-surfactant-polymer （ASP） flooding using sodium hydroxide as the alkali component to enhance oil recovery in Daqing Oilfield, northeast China has been successful, but there are new problems in the treatment of produced crude. The alkali added forms stable water-in-crude oil emulsion, hence de-emulsification process is necessary to separate oil and water. The problems in enhanced oil recovery with ASP flooding were investigated in laboratory by using fractions of Daqing crude oil. The oil was separated into aliphatics, aromatics, resin and asphaltene fractions. These fractions were then mixed with an additive-free jet fuel to form model oils. The interfacial properties, such as interfacial tension and interracial pressure of the systems were also measured, which together with the molecular parameters of the fractions were all used to investigate the problems in the enhanced oil recovery. In our work, it was found that sodium hydroxide solution reacts with the acidic hydrogen in the fractions of crude oil and forms soap-like interfacially active components, which accumulate at the crude oil-water interface.

Interfacial Interaction Between Polyurethane/Poly(Methacrylateco-Styrene) Coating and the Regenerated Cellulose Film

Water-resistant films were prepared by coating the surface of regenerated cellulose films with castor oil-based polyurethane (PU)/ poly-(methacrylate-co-styrene) [P (MA-St)]. The effects of the ratio of PU to P (MA-St) copolymer on tensile strength (dry and wet states), vapor permeability, size stability, and water resistivity of the coated films were studied. The interfacial interaction between cellulose and the PU/P (MA-St) coating was analyzed using infrared (IR), ultraviolet (UV), scanning electron microscopy (SEM), transmission electron microscopy (TEM), differential thermal analysis (DTA), and electron probe microanalysis (EPMA). The results indicated that the mechanical properties and water resistivity of the coated films significantly enhanced, and the biodegradability was displayed, when the ratio of PU to P (MA-St) was 8∶2 by weight. The chemical bonds and hydrogen bonds between the cellulose, PU, and the copolymer exist in the coated films. It is regarded that PU/P (MA-St) semi-interpenetrating polymer networks (IPNs) were formed, and a shared network of PU with both the cellulose and the coating in the coated film occurred simultaneously resulting in a strong bonding between the coating layer and the film.

STUDIES ON TUNG OIL COATED REGENERATED CELLULOSE FILMS WITH WATERRESISTANCE

Regenerated cellulose films with water-resistance were obtained by an improved method ofpreparing cellulose cuoxam solution from pulps of agricultural wastes (linters, wheat straw, reedand Bamao). Experimental results showed that the mechanical properties of both the dry. and wetfilms were excellent. Data from IR, SEM and tensile strength measurements implied that thesignificant improvement of water-resistance of the films was due to the cohesion between the thinTung oil covers with hydrophobicity and the regenerated cellulose films. The films werecompletely biodegraded after being buried in soil for 100 days. The transmittance of the filmsderived from linter and reed in visible band range were 80-90%.

An analytical model for water-oil two-phase flow in inorganic nanopores in shale oil reservoirs

The existence of water phase occupies oil flow area and impacts the confined oil flow behavior at the solid substrate in inorganic nanopores of shale oil reservoirs,resulting in a completely different flow pattern when compared with the single oil phase flow.This study proposes an analytical model to describe the water-oil two-phase flow.In this model,water slippage at the solid substrate is considered while oil slip is introduced to calculate the oil movement at the solid-oil boundary in dry conditions.It is proven that the oil flow profiles of both the two-phase model and single-phase model show parabolic shapes,but the oil flow capacity drops when water takes up the flow space and the impact of water is more significant when the pore dimension is smaller than 30 nm.Also,the oil flow velocity at a pore center is found to drop linearly given a larger water saturation in wet conditions.The effects of surface wettability and oil properties on water-oil flow are also discussed.Compared with the existing singlephase models,this model describes oil flow pattern in the wet condition with the incorporation of the influence of nanopore properties,which better predicts the oil transport in actual reservoir conditions.Water-oil relative permeability curves are also obtained to improve oil yield.

表面活性剂对水驱普通稠油油藏的乳化驱油机理

为了研究乳化降黏驱油剂对不同渗透率的水驱普通稠油油藏的驱油效率和孔隙尺度增效机理,选取了烷基酚聚氧乙烯醚(J1)、α-烯基磺酸盐类表面活性剂(J2)、十二烷基羟磺基甜菜碱(J3)、J3与烷基酚聚氧乙烯醚羧酸盐复配表面活性剂(J4)作为驱油剂,开展了4种驱油剂一维驱油和微观驱油模拟实验,明确了乳化降黏驱油剂在孔隙尺度的致效机理。结果表明,降低界面张力对提高驱油效率的作用大于提高乳化降黏率。在油藏条件下,乳化降黏驱油剂需要依靠乳化降黏和降低界面张力的协同增效作用,才能大幅提高驱油效率。乳化降黏驱油剂的乳化能力越强、油水界面张力越低,驱油效率增幅越大。当化学剂乳化降黏率达到95%时,油水界面张力从10^(-1)mN/m每降低1个数量级,化学剂在高渗透和低渗透岩心中的驱油效率依次提高约10.0%和7.8%。乳化降黏驱油剂注入初期通过降低界面张力,使得高渗透岩心和低渗透岩心中的驱替压力分别为水驱注入压力的1/2和1/3,从而提高注入能力。注入后期大块的原油被乳化形成大量不同尺寸的油滴,增强原油流动性,提高驱油效率。乳化形成的界面相对稳定的稠油油滴,能暂堵岩石的喉道和大块稠油与岩石颗粒形成的通道。油滴的暂堵叠加效应,使高渗透和低渗透岩心的驱替压差分别为水驱压差的5.2倍和32.3倍,大幅提高了注入压力,从而扩大平面波及面积。降黏驱油剂驱油实现了提高驱油效率的同时扩大波及范围。研究结果为水驱稠油开发用驱油剂的研发提供参考,为大幅提高水驱普通稠油采收率奠定基础。

破乳剂存在下两亲聚合物对乳状液的影响研究

从体相和界面两个方面开展了破乳剂存在下两亲聚合物对乳状液的影响研究。结果表明:具有两亲性的聚合物易于吸附在油水界面上参与界面成膜,溶液中加入一定质量浓度破乳剂后,虽然破乳剂可以部分取代吸附在界面膜上的两亲聚合物分子,减弱界面膜强度,但随着溶液中两亲聚合物质量浓度的增加,体系界面活性增加,溶液中两亲聚合物分子伸向油相的疏水基团增多,同时伸向油相的两亲聚合物分子中的部分疏水基团与体相两亲聚合物疏水基团的缔合作用也增强,所形成的油水界面膜黏度增大,界面膜弹性特征增强,界面膜的强度随着两亲聚合物质量浓度的增加而增大。

新型水上油膜厚度测量系统研制

浮油污染对生态环境造成了严重的影响,各国投入大量资金和人力用于水上浮油的研究。其中,水上油膜厚度的高精度测量对于浮油预防与处理至关重要。以柴油为研究对象,利用傅里叶变换红外光谱仪获取了不同温度下(293/298/303/308/313/318 K)柴油和常温下(298 K)水的吸收光谱,发现柴油和水在近红外区域(6000.0~11000.0 cm^(-1))存在明显吸收,且柴油的吸收光谱不随温度发生偏移。选取了柴油吸收系数最大的波数位置ν_(1)(8381.6 cm^(-1))用于建立单波长水上油膜厚度反演模型。选取了ν_(1)和吸收系数趋于零的波数位置ν_(2)(8918.7 cm^(-1))用于建立双波长水上油膜厚度反演模型。此外,水在这两个波数位置的吸收系数极小,对测量结果几乎没有影响。利用已知油膜厚度(0~1000μm)的标准具对两种反演模型的测量精度进行验证,发现两种模型获得的膜厚值与已知值的平均相对偏差分别为36.4%和2.5%,最大相对偏差分别为44.7%和3.7%,最大标准差分别为7.0和5.6μm。可见,双波长水上油膜厚度反演模型明显优于单波长水上油膜厚度反演模型。在此基础上,研制了一套基于双波长吸收光谱法的新型水上油膜厚度测量系统,该系统的时间分辨率为0.03 s。最后,利用该系统研究水面上逐滴滴入一定体积(1 mL)柴油后的水上油膜厚度变化,并结合超声脉冲反射法进行同步测量对比分析。每滴入一次柴油利用两种方法各重复测量10次,总共测量了20组油膜厚度数据(16~35 mL),将两种方法测量结果的平均值进行对比。结果表明,两种方法测得的油膜厚度平均相对偏差为2.5%,最大相对偏差为3.7%。其中,双波长吸收光谱法10次重复测量获得的油膜厚度的最大标准差为6.4μm。综上所述,所研制的系统可以实现高精度测量水上油膜厚度,具有无干扰、响应快、结构紧凑等优势,且可应用于不同类型的浮油测量,有望为溢油的监控、预防和处理提供新思路和科学指导。

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。

降低轧机支承辊油膜润滑油含水量方法的研究

以酸轧联合机组轧机支承辊油膜润滑系统为研究对象,以降低在线油膜润滑油含水量为任务目标,综合分析现场油膜润滑系统进水原因,研究一种方便易行的能够降低油膜油含水量的操作方法,既能为轧辊轴承提供良好的润滑保障,又能解决润滑油长期含水量居高不下的问题,延长润滑油使用寿命,减少碳排放,实现降本增效及环保生产。

微量油辅助水润滑成膜特性的研究

由于水的润滑膜建立能力较差,本文中研究了微量环保型润滑油辅助水润滑的润滑膜建立机制.利用滚子-盘接触润滑膜测量仪,研究了水环境下2种黏度的环保型润滑油作为第二介质的辅助润滑特性,并通过荧光标记对油的流动进行了观测.结果表明,水环境下滚子-盘接触区的润滑油主要来源于入口油池和侧油脊.与在空气中不同,水环境使油在固体表面的润湿性变低,接触区供油易受外界干扰,膜厚易发生波动.低速下侧油脊更容易向接触区回流,从而改善供油;在高速下水的逆流推动侧油脊回流的油远离接触区,导致入口供油变差.此外,环块试验机结果表明微量环保型润滑油辅助水润滑具备良好的减摩抗磨能力.

油润滑下水含量对DLC薄膜摩擦学性能的影响

类金刚石(DLC)薄膜已被广泛应用于发动机核心部件的摩擦学防护。为了研究在发动机运行工况下水含量对DLC薄膜摩擦学性能的影响,本研究以水-PAO6混合乳液为润滑剂,考察了发动机中广泛使用的2种DLC薄膜(a-C薄膜和a-C:H薄膜)在不同温度下的摩擦磨损性能。结果表明:在水-PAO6混合乳液的润滑条件下,摩擦系数受含水量的影响较小,总体上存在小幅增加。a-C薄膜部分失效,而a-C:H薄膜尚未出现基底暴露现象,2种薄膜的磨损率随着含水量的增加而降低。表面分析表明,水含量的增加抑制了二硫代氨基甲酸钼(MoDTC)的降解过程,从而减少了润滑添加剂MoS_(2)的形成。此外,水含量的升高还促进了碳向对偶球表面的转移。碳质转移膜、MoS_(2)和铁氧化物的共同作用影响了DLC薄膜的摩擦学行为。

水基钻井液复合纳米成膜封堵剂的制备及性能

以改性纳米SiO_(2)为刚性粒子,丙烯酰胺、2-丙烯酰胺基-2-甲基丙磺酸、苯乙烯和醋酸乙烯酯为聚合单体,壬基酚聚氧乙烯醚(10)和十二烷基磺酸钠为乳化剂,过硫酸铵和亚硫酸氢钠为引发剂,合成了一种有机/无机复合纳米成膜封堵剂。采用FTIR、SEM、动态光散射(DLS)和TGA对产物进行了表征和测试。考察了不同质量分数复合纳米成膜封堵剂对水基钻井液的流变性、滤失性及封堵性能的影响。结果表明,复合纳米成膜封堵剂呈球形,并保持纳米级分布,中值粒径为325 nm;340℃时的质量损失率为14%;120℃、16 h老化后较老化前表观黏度和塑性黏度均明显增加。当复合纳米成膜封堵剂质量分数为3%时,水基钻井液的静滤失量为10 mL;当质量分数≥2%后,砂床滤失量为0;当质量分数从0增至4%时,高温高压滤失量从104 mL减至29 mL,渗透性为1.56×10^(–2)mD,封堵率为90.7%。

二维碳基Janus薄膜的研究进展

以碳纳米管(CNTs)及石墨烯为代表的碳纳米材料具有卓越的物理、化学、电学和光学性质。其可控组装的二维碳基薄膜具有高比表面积、高透过率和良好柔性,广泛应用于柔性薄膜、微电子器件及储能领域。在此基础上引入高分子组分结合形成二维碳基Janus薄膜,不仅维持了其导电导热性,还结合了高分子的刺激响应和调控特性,通过非对称特征,实现了物理和化学性质的协同,大幅拓宽了其应用领域。文中综述了二维碳基Janus薄膜的研究近况。首先从物理法和化学法两方面介绍了二维碳基Janus薄膜的制备方法及其优缺点,物理法包括界面成膜法、真空抽滤法和层层组装法等;化学法包含界面聚合及化学接枝等方法。然后总结了二维碳基Janus薄膜在传感、驱动、海水淡化、油水分离等多个领域的应用现状。最后讨论了二维碳基Janus膜的发展前景及面临的挑战。

纳米颗粒间相互作用对油-水界面张力的影响机制

为了研究油-水界面上纳米颗粒的动态吸附过程及其对界面张力的影响,采用耗散粒子动力学模拟方法,建立纳米颗粒在油-水界面物理模型,研究单颗粒的吸附动力学过程及多颗粒相互作用对界面张力的影响机制。结果表明:单颗粒在油-水界面的吸附分为自由扩散、界面吸附、动态平衡3个阶段;单颗粒吸附过程自由能变化远大于颗粒的动能,颗粒吸附可自发、快速进行,且吸附后能稳定在界面上;多颗粒间的相互作用力随颗粒间距离的增大而振荡衰减,这是由颗粒间的溶剂粒子所产生的溶剂化效应所致;当颗粒间相互作用为引力时,界面张力增大,当颗粒间相互作用为斥力时,界面张力减小。

液滴撞击深池上覆油膜的空腔演化特性

为探究液滴撞击深池上覆油膜特性,通过实验和理论方法研究撞击过程中的空腔演化动力特性,构建了多界面模型。结果表明:液滴-油膜-液池的不相溶特性导致更复杂的空腔演化过程,对于较小的弗劳德数Fr条件下,子液滴的产生原因是向下射流发生Rayleigh-Plateau不稳定性。对于大Fr条件下,撞击后形变液滴收缩导致的Rayleigh-Plateau不稳定性是导致子液滴形成的主要原因;由于不相溶界面上的切应力影响,空腔初始扩展速度随着形变界面数量增加而减小;对于薄液膜,由于未考虑油膜-深池界面形变的界面能,其无量纲空腔深度d'与Fr之间关系不满足经典关系d′-F_(r)^(1/4)。而对于厚液膜,其撞击过程可被视为水滴撞击油池,实验观测满足经典关系;采用多界面模型求解获得的有效空腔深度d'_(e)与Fr之间关系满足d′_(e)~F_(r)^(1/4)。

油田深度调剖化学剂驱油效率与机理

随着石油资源的日益紧张,提高油田开采效率成了石油行业面临的主要挑战。选用3种不同的化学剂(PAM、SDBS、PAA)并通过测定岩心渗透率和油水界面张力进行驱油效率实验。实验结果显示,PAA在提高岩石渗透率方面表现最为突出,从130.14 m D增加到212.43 m D,增幅为63.2%,而SDBS则在降低油水界面张力方面表现最佳,从38.92 m N·m^(-1)降至21.00 m N·m^(-1),降低了46.2%。此外,在中温(40℃)和中压(20 MPa)以及适中的注入流量(100 L·min^(-1))下,驱油效率达到最优。化学剂在改变岩石孔隙结构及降低油水界面张力方面的作用,共同促进了油水流动性的提升,从而显著增强了整体的驱油效果。研究结果对于指导实际油田作业中化学剂的选择和应用具有重要的参考价值,为油田开发提供了新的视角和方法。

新型表面活性剂提升油气开发采收率的影响研究

为了提升油气开发采收率,通常会使用表面活性剂。但是由于单一表面活性剂无法实现超低表面张力(IFT)和强亲水条件,因此传统的表面活性剂驱的油气开发采收率受到了影响。为了解决这些问题,通过表面活性剂混合物来实现提高石油采收率是一种较为可行的方案。检验了新型复合表面活性剂作为提高石油采收率的潜在手段的方案,结果表明,与单独的表面活性剂溶液相比,复合表面活性剂对油水表面张力和润湿性变化具有更显著的影响。使用复合表面活性剂系统可获得超低的表面张力(约0.006 mN·m^(-1)),因此研究认为此种新型复合表面活性剂有效并可投入油田开发。

高效深度调剖化学剂在提高采收率中的应用及机理研究

通过高效液相色谱分析、界面张力仪测量、岩心驱替实验和扫描电子显微镜观察等实验方法,探究了高效深度调剖化学剂在提高采收率中的应用及其作用机理。结果表明:该化学剂主要由交联聚合物(58.6%)、表面活性剂(29.5%)和纳米粒子(11.9%)组成,具有良好的流变性能和热稳定性。化学剂在25℃时的黏度为121.6 mPa·s,随温度升高而降低,但在100℃时仍保持58.3 mPa·s的黏度;化学剂能显著降低油水界面张力,从32.6 mN·m^(-1)降至9.6 mN·m^(-1);在岩心驱替实验中,使用该化学剂后的额外采收率达到了19.2%,总采收率提高到47.8%,最佳的注入参数组合为化学剂质量分数0.5%,注入速率0.5 mL·min^(-1),注入量1.0 PV。机理分析表明,该化学剂通过降低油水界面张力、改善油藏渗透性、调整流动阻力和改变孔隙结构等多重机制,有效提高了采收率。该研究为油田的高效开发提供了新的技术支持,对于提高油田采收率具有重要的理论意义和应用价值。