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。     

柴油-甲醇乳化燃料乳化剂的最佳HLB值及水含量的影响

柴油机中掺烧醇的最大难点之一在于难以获得价廉、稳定的柴油-甲醇乳化燃料。作者研究了柴油-甲醇乳化燃料乳化剂的最佳HLB值以及不同含水量对最佳HLB值的影响。研究结果表明：柴油-甲醇乳化燃料乳化剂的最佳HLB值在3．5左右，当柴油甲醇乳化燃料中含水形成了甲醇-水-柴油三元乳化燃料时，其最佳HLB值与柴油-水的最佳HLB值相同，且三元乳化燃料乳化剂的最佳HLB值不随含水量的增加而变化，但随着含水量增加，乳化燃料分层时间会产生变化；在柴油-甲醇-水乳化液中，当水在甲醇-水混合液中的比例为40％左右时，甲醇-水-柴油三元乳化燃料(柴油：甲醇 水=8：1)的分层时问最长，即在柴油-甲醇乳化燃料中加水有利于提高乳化燃料的稳定性。     

生物油/柴油乳化燃料用于柴油机的试验研究

为研究生物油/柴油乳化燃料作为柴油机燃料的性能,通过添加适量乳化剂配制成乳化燃料并在柴油机上燃用,分析了乳化燃料的燃烧特性、经济性、排放特性及对柴油机的影响.结果表明:生物油与柴油可以通过乳化形成较稳定的乳化燃料且可将其用于柴油机,但燃油消耗率比柴油高,热效率比单一柴油低;CH和CO排放增加,NO_x排放降低;使用一段时间后,供油管路中的橡胶密封件出现溶胀效应,排放因喷油器被磨蚀而随时间呈非正常变化.试验对进一步研究生物油在柴油机上的应用具有重要意义.     

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。     

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.     

生物油/柴油乳化燃料的稳定性及理化性质

利用非离子表面活性剂复配,对热解生物油/柴油混合液进行一系列乳化实验,测量乳化油的密度、热值、pH值.以乳化油的稳定性为实验指标,研究乳化剂种类、乳化剂用量、生物油含量对乳化油稳定性的影响.实验结果表明:在乳化温度为40℃(水浴),乳化时间为30min的条件下,以2%用量的Span80和Tween80复配乳化剂乳化生物油含量为20%的生物油/柴油混合液效果最佳.另外,随着生物油含量的增加,乳化油密度逐渐增加,热值与pH值逐渐减小.     

柴油乳状液的制备

以HLB值选择乳化剂制备柴油乳状液，系统地考察了复合乳化剂HLB值，乳化温度、极性添加物、搅拌方式、乳化时间、水质等对乳状液稳定性的影响．     

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。     

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.     

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.     

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.     

Impact of Carbon Nanotubes and Di-Ethyl Ether as additives with biodiesel emulsion fuels in a diesel engine – An experimental investigation

In the current global energy scenario, fossil fuels face challenges with regards to exorbitant demand, environmental hazards and escalating costs. In this regard, the technical community is in quest for alternative resources. In this context, biodiesel fuel is potentially considered as alternative fuels for compression ignition engines. Hence, in this current investigation, biodiesel and biodiesel emulsions are prepared from a vegetable oil and further subjected for the blending with potential additives such as CNT (Carbon Nanotubes) and DEE (Di-Ethyl Ether) to improve the working attributes of the diesel engine. The entire investigation was carried out in five stages. In the first stage, both pure diesel and biodiesel (derived from jatropha oil) fuels were tested in the diesel engine to obtain baseline readings. In the second stage, water–biodiesel emulsion fuel was prepared in the proportion of 91% of biodiesel, 5% of water and 4% of emulsifiers (by volume). In the third stage, 50 ppm of CNT, 50 ml of DEE and combined mixture of CNT+DEE (50 ppm CNT+50 ml DEE) were mixed with the water–biodiesel emulsion fuel separately to prepare the CNT and DEE blended water–biodiesel emulsion fuels respectively. In fourth stage, the prepared emulsion fuels were subjected to stability investigations. In the fifth stage, all the prepared stable emulsion fuels were subjected for experimental testing in a diesel engine. It was observed that the CNT and DEE blended biodiesel emulsion fuels reflected better performance, emission and combustion attributes than that of pure diesel and biodiesel. At the full load, the brake thermal efficiency, NO and smoke emission of CNT+DEE fuels was 28.8%, 895 ppm and 36%, whereas it was 25.2%, 1340 ppm and 71% for pure diesel respectively. It was also observed that on adding CNT and DEE with the biodiesel emulsion fuels, the ignition delay was shortened and henceforth, the additive blended biodiesel emulsion fuels exhibited higher brake thermal efficiency and reduced emissions (NO, smoke) than that of pure diesel and biodiesel.     

Experimental investigation on diesel engine with diestrol-water micro emulsions

Experiments were conducted on a single cylinder direct injection diesel engine using diesel, biodiesel and biodiesel-diesel-ethanol (diestrol) water micro emulsion fuels to investigate the performance, emission and combustion characteristics of the engine under different load conditions at a constant speed of 1500 rpm. The results indicated that biodiesel and micro emulsion fuels had a higher brake specific fuel consumption (BSFC) than that of diesel. A slight improvement in the brake specific energy consumption (BSEC) was observed for micro emulsion fuels. The brake thermal efficiency of biodiesel and micro emulsion fuels were comparable to that of diesel. The emission characteristics like carbon monoxide (CO), carbon dioxide (CO₂), unburnt hydrocarbon (UHC), nitric oxide (NO) and smoke emissions for biodiesel and micro emulsion fuels were lower than diesel fuel at all load conditions. The cylinder gas pressure of micro emulsion fuels was lower than diesel at low loads but it became almost identical to diesel at medium and full load conditions. The heat release rate for micro emulsion fuels was higher than biodiesel and diesel fuels for all loads. Biodiesel showed shorter ignition delay for the entire load range and the longer ignition delay observed for micro emulsion fuels.     

柴油乳化燃料的配制及应用

本文系统地介绍了柴油乳化燃料的配制设备、方法及其稳定性影响因素,其中阐明了除使用合适的乳化设备外,应用恰当的乳化方法,如混合膜生成法也可得到性能比较稳定的乳化燃料;利用配比合适的Ｓｐａｎ８０和Ｔｗｅｅｎ８０混合乳化剂可在油－水界面上形成络合物,使乳化液更趋稳定;乳化液两相密度差也是影响其稳定性的重要因素之一。文章最后对柴油乳化燃料的应用作了分类总结,指出柴油－甲醇(乙醇)－水复合乳化燃料和植物油燃料是代用燃料的今后发展趋势。     

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.     

Emission analysis of diesel engine fueled with soybean biodiesel and its water blends

The present study is carried out to formulate stable water-in-soybean biodiesel emulsion fuel and investigate its emission characteristics in a single cylinder diesel engine. Four types of emulsion fuels, which consist of a different percentage of water (5%, 10%, 15%, and 20%) in soybean biodiesel, were prepared with suitable surfactant and properties were measured. The physicochemical properties are on par with EN 14214 standards. The experimental result of test fuels indicates that the soybean biodiesel promotes a lower level of hydrocarbon (HC), carbon monoxide (CO) and smoke emissions compared to base diesel except for nitrogen oxide (NOx) emission. Increase in water concentration with soybean biodiesel significantly reduces the NOx emission and smoke opacity. The HC and CO emissions are further reduced with emulsified biodiesel up to 10% water concentration and beyond that limit, marginal increases are recorded. Overall, it is observed that inclusion of water with soybean biodiesel reduces the HC, CO, NOx and smoke emissions when compared to base diesel and soybean biodiesel, and 10% water in soybean biodiesel is an appropriate solution to reduce the overall emissions in the soybean-fuelled diesel engine.