生物柴油-生物质油乳化燃料最佳HLB值研究

生物质油是生物质快速热解液化的产物,与生物柴油乳化后可得到一种新的可再生清洁燃料.利用超声波乳化装置制备生物柴油-生物质油乳化燃料,首先采用亲油亲水平衡(HLB)值法确定了生物柴油-生物质油乳化燃料乳化剂的最佳HLB值,然后研究了乳化燃料制备过程中各种乳化条件对乳化燃料稳定性的影响.结果表明,生物柴油-生物质油乳化燃料乳化剂的最佳HLB值为4.3～4.7,乳化时间、乳化温度、生物质油浓度及乳化剂浓度等对乳化燃料的稳定性均有一定的影响.     

生物油/柴油乳化实验研究

采用菠萝松快速热裂解生物油进行了生物油/柴油的乳液燃料制备研究,重点考察了乳化剂HLB值、乳化强度和乳化时间等因素对生物油/柴油乳液稳定时间的影响。在选用的一系列乳化剂HLB值中,当HLB值为7时生物油/柴油乳液稳定时间最长,达到了350 h。为深入分析乳液微观结构对其稳定时间的影响,采用马尔文纳米粒度分析仪对乳液进行了微观结构观察,发现乳液燃料的粒径主要集中在0.3～1μm,并且稳定时间越长的乳液其液滴粒径也越小。     

微乳化甲醇柴油的稳定性研究

采用油酸、乙酸乙酯、异丁醇和大豆油作为微乳化剂制备出微乳化甲醇柴油。分析了油酸、乙酸乙酯、不同碳链醇和水的质量含量对微乳化甲醇柴油的分层时间和分层温度的影响。研究结果表明:油酸的质量含量大于7%时可以使甲醇柴油稳定保存一年,分层温度为70℃;乙酸乙酯的质量含量大于5%时可以使甲醇柴油稳定保存一年,分层温度为75℃;异丁醇对甲醇柴油稳定作用最好,可以使甲醇柴油稳定保存一年,分层温度为70℃;含水量低于4%时,可以使甲醇柴油稳定保存一年,含水量大于4%时,分层温度降为50℃。     

机械搅拌制备柴油-甲醇-水乳化燃料的研究

探讨了用机械搅拌法制备柴油－甲醇－水复合乳化燃料的机理，认为乳化过程是在强制对流作用下的强制混合过程，是主体对流扩散和涡流扩散两种扩散机理综合作用的结果，但混合速度取决于涡流扩散的速度。对采用SG－2乳化剂在机械搅拌乳化装置上配置柴油－甲醇－水复合乳化液的工艺进行了试验研究，结果表明，搅拌槽的挡板，搅拌器的叶轮转速，搅拌时间，乳化剂含量和甲醇中的含水量等参数对乳化液的稳定性有重要的影响。     

生物质焦油/柴油超声乳化工艺及其燃烧特性研究

文章利用超声波乳化技术将焦油与柴油进行乳化提质,分别从焦油含量、HLB值、乳化剂添加量、助乳剂种类4个乳化参数以及超声功率密度、超声作用时间两个超声参数对生物质焦油/柴油乳化体系进行优化工艺研究,并利用热重方法对乳化油进行燃烧特性分析。研究结果表明:当焦油体积含量为7%,HLB值为5,乳化剂的体积含量为5%,助乳剂为甲醇,超声功率密度为0.96 W/mL,超声作用时间为20 min时,乳化油的稳定性最好,稳定时间达到104 min,浊度值为226.08;对生物质焦油、柴油、乳化油进行燃烧特性分析,发现乳化油与柴油具有相似的燃烧特性。     

CLZ微乳化乙醇柴油混合燃料的发动机性能研究

基于亲油-亲水平衡(HLB值)理论和乳化原理,研究了单试剂和复合试剂作为乳化剂对乙醇柴油混合燃料体系的乳化效果和稳定性的影响,开发了一种以生物油、蓖麻油以及其他几种单试剂复配而成的CLZ复配型乳化剂,结果表明:CLZ复配型乳化剂较好地解决了E10乙醇柴油体系在较宽广温度范围内的物理稳定性问题,对E15乙醇柴油混合体系有较强的乳化能力,能使乙醇柴油混合燃料长期保持良好的物理稳定性.通过试验对比研究了乙醇柴油燃料对柴油机性能的影响,结果表明:燃用乙醇柴油混合燃料后,当量燃油消耗率降低,有效热效率提高,CO排放量低负荷时升高、高负荷时下降;NOx排放量略低于燃用纯柴油水平;THC排放量高于燃用纯柴油水平,碳烟排放量相比纯柴油大幅度下降.     

柴油机燃用柴油－甲醇－水复合乳化燃料的研究

本文介绍柴油机燃用柴油－甲醇－水复合乳化燃料的研究。采用自行研制的复合型乳化剂、使用机械搅拌分步乳化法和超声乳化法配制了多种配比的复合乳化燃料。通过台架试验得出了复合乳化燃料的最佳配比，分析了燃用不同配比的复合乳化燃料对柴油机的经济性、动力性、燃烧过程和排放特性的影响；使用全气缸取样系统研究了柴油机燃用不同燃料时缸内微粒生成历程。试验表明，燃用复合乳化燃料时缸内微粒生成量大幅度减少，下降值最大可达４０．７％，首次以实验手段揭示了柴油机燃用乳化燃料时烟度降低的关键原因。试验也表明，这种复合乳化燃料具有乳化剂用量少、稳定性好的特点；ＺＨ１９０Ｗ型柴油机燃用Ｄ８５Ｍ７．５Ｗ７．５复合乳化燃料时获得了满意的性能．     

乳化柴油的应用研究

采用HLB值法进行筛选，复配出乳化效果和稳定性均较好的三种混合乳化剂。将乳化剂按1％、水20％掺入纯柴油，采用乳化剂在油中法，手工振荡制备出的油包水型乳化柴油，其稳定时间可达1个月。经过大量的台架试验表明：配制的乳化柴油与原纯柴油相比，平均节油率超过10％，主要排放物NOx降低超过10％、碳烟降低50％以上。     

柴油—甲醇—水复合乳化燃料的试验研究

本文介绍了一种适合于柴油 -甲醇 -水复合乳化的新型乳化剂的制取方法 ,分析了该种乳化剂的乳化机理 ,探讨了用CR - 2型乳化装置配制柴油 -甲醇 -水复合乳液的工艺 ,并在柴油机台架上进行了试验研究。     

生物柴油-甲醇-水微乳化的试验研究

使用微乳化剂制备得到的油包水型(W/O)乳化生物柴油,能够有效地使油、水、甲醇相容而形成较为稳定的微乳化体系.通过筛选最佳微乳化剂,研究了微乳化剂在生物柴油微乳化过程中的应用,考察了微乳化剂种类、用量、温度等冈素对微乳化生物柴油中水、甲醇掺人量的影响.结果表明:以油酸,氨水作为微乳化剂,正丁醇为助剂,剂油质量比为3:14.温度为50℃时,即可制备清澈透明,稳定性好,水、甲醇掺入量为17.23%的微乳化生物柴油.     

生物质热解生物油与柴油乳化的试验研究

通过生物质热解生物油模型化合物与柴油乳化的研究确定了乳化剂合适的HLB范围,在该范围内稻壳热解生物油与柴油的乳化效果良好,同时研究了生物油贮存时间对乳化效果的影响。在柴油、乳化剂和生物油质量分数分别为92%、3%和5%,试验研究了不同种类生物质热解生物油与柴油的乳化性能,乳化燃料在热值上接近柴油,粘度符合国家轻柴油标准,具有商业应用的可能。最后通过生物油和柴油乳化的三组分相图分析了形成稳定乳液时三组分的相对含量变化。     

三相乳化油的制备与物理性质研究

用两步法配制油包水包油（O／W／O）三相乳化油，首先用亲水性表面活性剂Tween60制成水包油（O／W）乳化液，然后用亲油性表面活性剂Span60将O／W乳化液制成O／W／O三相乳化油。进一步研究乳化剂的亲水亲油平衡值（HLB）、掺水量对O／W／O三相乳化油的乳化稳定性（ES），乳化活性（EA）及运动黏度等物理性质的影响。试验发现，采用表面活性剂span60和Tween60作为乳化剂，当HLB值为6到9，掺水量为10％，表面活性剂总的添加量为2％时，O／W／O三相乳化油具有合适的运动黏度和稳定性，适合作为柴油机的代用燃料。     

Phase change emulsions for latent heat transportation:Preparation and characterization

采用相转化乳化法,以Tween80+Span80为复配乳化剂,通过优化复配乳化剂的比例以及优选不同的助乳化剂(稳定剂),制备了固含量高达40%的石蜡相变乳状液.分别采用NDJ-1黏度仪和DSC-Q10热流式差示扫描量热仪测试了石蜡相变乳状液的黏度和潜热.结果表明:当复配乳化剂的HLB值在10附近时,即Span80占46.8%(质量分数),Tween80占53.2%(质量分数),以正丁醇为助乳化剂,可制得分散均匀稳定,流动性好的石蜡相变乳状液,该相变乳状液的黏度随石蜡含量的增加而急剧增大,而潜热则在油相/水相共存时达到最大.当乳状液为油相时,潜热随含水量的增加而增大;当乳状液为水相时,潜热随含水量的增加而减小.     

Performance and emission characteristics of a diesel engine operating on different water in diesel emulsion fuels: optimization using response surface methodology (RSM)

The nitrogen oxide (NO_x) release of diesel engines can be reduced using water in diesel emulsion fuel without any engine modification. In the present paper, different formulations of water in diesel emulsion fuels were prepared by ultrasonic irradiation. The water droplet size in the emulsion, polydisperisty index, and the stability of prepared fuel was examined, experimentally. Afterwards, the performance characteristics and exhaust emission of a single cylinder air-cooled diesel engine were investigated using different water in diesel emulsion fuels. The effect of water content (in the range of 5%–10% by volume), surfactant content (in the range of 0.5%–2% by volume), and hydrophilic-lipophilic balance (HLB) (in the range of 5–8) was examined using Box-Behnken design (BBD) as a subset of response surface methodology (RSM). Considering multi-objective optimization, the best formulation for the emulsion fuel was found to be 5% water, 2% surfactant, and HLB of 6.8. A comparison was made between the best emulsion fuel and the neat diesel fuel for engine performance and emission characteristics. A considerable decrease in the nitrogen oxide emission (–18.24%) was observed for the best emulsion fuel compared to neat diesel fuel.     

三组元W／O乳化液的表面张力和雾化特性

研究了W/O型乳化液的表面张力,压力雾化喷嘴的乳化液雾化特性与乳化液的组分、乳化剂的黏度以及喷油压力的关系.实验结果表明:乳化液的表面张力接近柴油,但喷雾滴径均大于柴油,而且喷嘴的启喷压力、乳化液组分和乳化剂黏度对乳化液平均滴径均有显著影响.随着启喷压力升高,喷雾滴径明显减小;若启喷压力相同,随着乳化液中水相含量增加(不高于50%),乳化液喷雾滴径随之增加;采用高黏度、低HLB值乳化剂配制的乳化液的喷雾滴径相对较大;内相界面特性和界面上的乳化剂会对滴径分布有重要影响.     

Formulation of stable water-in-diesel emulsion fuel and investigation of its properties

The use of water-in-diesel emulsion fuel has the potential to significantly reduce the formation of oxides of nitrogen (NO_X), particulate matter (PM), and total gaseous hydrocarbons (THC) in diesel engines without engine modification. The preparation of stable water-in-diesel emulsion fuel and its variation in properties is critical for the successful development of diesel engines. The present study was carried out to create a stable water-in-diesel emulsion fuel by analyzing the effects of different process variables on emulsion preparation, including surfactant hydrophilic–lipophilic balance (HLB), water concentration in diesel, and stirrer speed. The stability was analyzed by emulsion fuel density variation as a function of time using a photonic system on the emulsion surface. From the results obtained, it was found that sorbitan monolanrate mixed at maximum stirring speed gave optimal emulsion stability for all concentrations of water. The critical fuel properties (density, viscosity, heating value, flashpoint, and corrosiveness) were measured for stable emulsion fuel and compared to the European Standard of automotive fuel requirements. The results indicate that a concentration of water in excess of 10% failed to meet fuel requirements.     

Formulation and combustion of emulsified fuel: The changes in emission of carbonaceous residue

Burning dense, viscous combustibles such as heavy fuel‐oil as a water‐in‐oil emulsified combustible enables to decrease the emission of solid carbonaceous residue, in comparison with raw, non‐emulsified combustible. This is due to the phenomenon of micro‐explosion, meaning the rapid (<0.1 ms) vaporization of the water droplets inside the emulsion, breaking up the initial emulsion droplet into numerous and faster ‘daughter‐droplets’. The present work is based on a small‐scale furnace (300 kW max.) feed with heavy fuel‐oil mixed with 10–20% of gasoil, with and without emulsion of water. The emulsification of combustible enables to record a reproducible lowering in emission of carbonaceous residue from the combustion of emulsified fuel, in comparison with raw fuel. This is added to a variation in granulometry of carbonaceous residue, hereby considered as an indicator of second atomization. Copyright © 2009 John Wiley & Sons, Ltd.     

钻井液用两性离子P(AM-AMPS-DAC)共聚物反相乳液的制备与性能评价

作为钻井液处理剂,反相乳液聚合物与粉状聚合物相比,能够减少聚合物在烘干、粉碎过程中由于降解、交联等反应造成的不利影响,产品可以直接加入钻井液并快速分散,在达到同样效果的前提下,可减少用量,降低钻井液处理费用,且更容易实现绿色环保生产。以丙烯酰胺、2-丙烯酰胺-2-甲基丙磺酸、丙烯酰氧乙基三甲基氯化铵为原料,采用氧化还原引发剂体系,通过反相乳液聚合,制备了两性离子P(AM-AMPS-DAC)反相乳液聚合物。研究了复合乳化剂的HLB、乳化剂用量、引发剂用量、油水体积比、AMPS和DAC用量对共聚物的水溶液表观黏度及所处理钻井液的流变性和滤失量的影响,测定了聚合物的红外光谱和TG曲线。结果表明,当油水体积比为1.0,单体质量分数为30%,复合乳化剂质量分数为5%~6%,复合乳化剂HLB值为7.1,引发剂用量为0.2%,n(AM)∶n(AMPS)∶n(DAC)=0.59∶0.35∶0.06时,能够制得热稳定性好的反相乳液聚合物,且在淡水、盐水、饱和盐水和复合盐水基浆中具有较好的增黏、降滤失能力,抗温、抗盐能力强,同时具有较强的润滑和防塌能力。     

Modelling of mechanical microstructure changes in the catalyst layer of a polymer electrolyte membrane fuel cell

Microstructure changes in catalyst layers limit durability which is essential for the commercialization of polymer electrolyte membrane fuel cells. In this study, a mathematical model is developed for the mechanical changes in the microstructure of catalyst layers resulting from variations in clamping force, temperature and relative humidity. Finite element method is adopted and cohesive zone model is used to simulate the microstructure behavior, including the occurrence of delamination between different structures and phases as well as within the ionomer due to its breakdown (crack initiation). It is shown that subject to a startup and shutdown cycle, the interface between the ionomer and catalyst agglomerate can start to delaminate near the end of the shutdown process, and the change in the relative humidity is the dominant factor that influences the delamination process, because the ionomer in the catalyst layer structure expands and shrinks with its water content. The delamination between the ionomer and catalyst agglomerate is found to propagate or increase with the number of the startup and shutdown cycles, and nearly 90% of the interface delaminates after 100 cycles. The plastic strain inside the ionomer, which is not fully recoverable, accumulates (increases) with the cycling, although it is smaller than the breakdown strain of the ionomer after 100 cycles, it may lead to the internal crack initiation if the cycling continues.