Preparation of monodispersed emulsion with large droplets using microchannel emulsification

Microchannel (MC) emulsification is a novel technique for producing monodispersed emulsions with coefficients of variation of less than 5%. To produce emulsions with large droplets, we designed three MC with large dimensions. The MC structure consists of two parts: a channel and a terrace. Terrace length was defined as the length from the exit of the MC to the end of the terrace. The MC plates used in this study have deeper channels and longer terraces. The size limit of droplets prepared by MC emulsification was studied. Monodispersed emulsions with droplets as large as 100 μm were prepared using an MC with a depth of 16 μm and a terrace length of 240 μm. The average diameter (coefficient of variation) of the emulsion droplets was 98.1 μm (2.5%). Emulsions with larger-diameter droplets were prepared using an MC with a longer terrace. The effect of the applied pressure on emulsification behavior was studied and discussed from the viewpoint of the droplet formation mechanism. At low applied pressures, droplet diameters were independent of the applied pressure, and monodispersed emulsions were produced. The pressure ranges of constant droplet diameter for large-droplet emulsions were narrower than those for the 5 to 30 μm droplet size emulsions because interfacial tension is more significant on a smaller scale compared with the other forces.     

The study of methods of NOx inhibition during fuel combustion at power plants with allowance for the use of hydrogen additions

The paper considers methods of NO_x inhibition by affecting the process of NO_x formation. The dependences for the degree of NO_x concentration reduction while intensifying the flame cooling, during water spray to the furnace, and while using flue gases recirculation as well as during fuel emulsification or nonstoichiometric fuel combustion have been obtained. The obtained formulas include a set of parameters which could affect the final value of NO_x concentration. The effect of a given factor could be evaluated on the basis of these dependencies. The calculated degrees of NO_x inhibition display good agreement with full-scale experimental data. The authors study the effect of NO_x concentration on ignition of the alternative hydrogen fuel during co-combustion in the furnace volume. The analysis of experimental data on hydrogen ignition delay in the presence of nitrogen oxides has been carried out. It is shown that depending on NO_x concentration, minimum ignition delay could occur, i.e. minimum effect of additives on the quality of alternative hydrogen fuel combustion may be allowable.The results of the study could be used for design engineering of power plants with the reduced NO_x environmental effect.     

天然抗菌微胶囊的制备与应用

以黄柏提取液为芯材,乙基纤维素为壁材,采用乳化交联法制备天然抗菌微胶囊,并应用于纯棉针织物的抗菌整理中。分析探讨了微胶囊外观形貌、热稳定性、粒径分布以及整理后的针织物表面形态与抗菌等性能。结果表明,初乳中乳化剂含量为5.0%、乳化搅拌速度为1500 r/min、初乳中壳材用量为2.5%时制备的微胶囊表面状况较好;当微胶囊质量浓度为35 g/L,黏合剂含量为4.0%,热烘温度为40℃,整理试样对金黄色葡萄球菌和大肠杆菌的抗菌率分别可达81.33%和89.27%。     

喷雾干燥法制备微胶囊工艺研究

主要介绍了喷雾干燥技术制备微胶囊过程中的乳化液配置及相关喷雾干燥工艺参数对微胶囊化过程的影响.     

乳化炸药基质冷却的初步探索

针对乳化炸药实现连续化、自动化生产中出现的乳化炸药基质冷却的难题,分析了乳化过程温度的变化及乳化基质冷却的影响因素,对连续搅拌式冷却器冷却、静态混合式冷却器冷却、用于胶体磨的乳化基质冷却及自动搅拌冷却４种冷却技术进行了探索。     

Effect of block copolymers of various molecular architecture on the phase morphology and tensile properties of LDPE rich (LDPE/PS) blends

The emulsification efficiency of three different block copolymers consisting of hydrogenated polybutadiene (HPB) and polystyrene (PS), i.e. a pure diblock , a tapered diblock and a triblock copolymer has been compared in low density polyethylene/polystyrene (LDPE/PS) blends rich in polyethylene. The comparison relies upon the ability of these potential interfacial agents to stabilize fine phase dispersion and to promote good interfacial adhesion. Based on the phase morphology, the ultimate tensile properties and the dynamic viscosity of the modified blends, the tapered diblock copolymer is clearly the most efficient emulsifier. For instance a plateau is observed in the property-copolymer content dependence when 2 wt% tapered diblock are used compared to ca. 5 wt% in case of the pure diblock. In contrast, no plateau is observed when the triblock copolymer is used. This is assumed to result from a less quantitative localization of these two copolymers i.e. the pue diblock or the triblock at the LDPE/PS interface.     

稠油油田边部油井井筒乳化降黏技术研究及应用

渤海某油田边部3口油井投产后产油量低,未达到预测水平。通过与同区块油井对比分析,研究出原因是油井原油黏度高,增加了井筒举升过程中的阻力,影响了电泵效率。优选成本低、降黏率高的井筒乳化降粘的技术工艺,其机理为乳化降粘和润湿降阻两方面。实验表明该复合型稠油助采剂加入定量比例的情况下,可形成黏度在10~100m P·s范围内的乳化体系;并且在温度30~60℃范围内,黏度水平稳定,降粘效果明显。3口油井实施后日均增油26m3,降粘增油效果显著。     

乳化剂的含量对锌基涂层耐蚀性的影响

利用片状锌粉、铝粉、铬酐及其它有机物配制的新型高耐蚀锌基涂料具有良好的结合力和耐蚀性,详细讨论了乳化剂含量对锌基涂层耐蚀性的影响.涂层的耐蚀性采用中性盐雾试验和5%盐水浸润试验.试验证明,涂层的表面粗糙度随着乳化剂量的增加而逐渐变得平滑、细腻.乳化剂的加入,直接影响到是否能够使涂料充分混合,使涂料分散均匀,也影响到涂料的流平性和黏稠度,但它对涂层的耐蚀性影响不大,本试验控制在26g/L.     

石蜡氧化改性的发展及应用

介绍了石蜡的氧化改性方法,阐述了国内外石蜡氧化的生产现状和应用情况,指出了中国在石蜡氧化生产中面临的主要问题及今后的研究方向。     

Effects of cross-flow velocity, capillary pressure and oil viscosity on oil-in-water drop formation from a capillary

The formation of oil drops from a single capillary with a diameter of 200 μm into a cross-flowing continuous water phase has been studied experimentally with the particle image velocimetry (PIV) technique and numerically with the computational fluid dynamics (CFD) software Fluent. The drop formation time and the volume of the detached drop were used as validation parameters and the results from the two methods corresponded well, with a difference of less than 5% for the drop formation time and 10% for the drop volume. The cross-flow velocity has a major impact on drop size, which decreases as the cross-flow increases. An increase in cross-flow, oil viscosity and capillary pressure displace the position of necking and drop detachment away from the capillary opening, which will have a decreasing effect on the final size of the drop.