玉米秸秆生物油对直喷式柴油机燃烧与排放的影响

采用超声波乳化法制备了玉米秸秆热解生物油质量分数分别为5%、10%、15%和20%的生物油/柴油乳化油,分别记为CSB5、CSB10、CSB15和CSB20,然后在一台未作改动的直喷式柴油机上研究了其燃烧和排放特性,并与燃用0号柴油进行了比较,旨在为生物油在柴油机中的应用提供依据和理论指导.结果表明,随着生物油质量分数的增加,乳化油的滞燃期逐渐延长,预混燃烧放热量和预混燃烧期增加,燃烧持续期缩短;燃烧放热率峰值和最大压力升高率先增加后降低,最高燃烧压力和燃烧温度逐渐降低.燃用CSB5和CSB10时的燃油经济性与柴油相当,而燃用CSB15和CSB20时的燃油经济性较柴油的略差.与0号柴油相比,随着生物油含量的增加,乳化油的NOx排放逐渐降低,HC和CO排放逐渐增加;碳烟排放先降低后增加,CSB5和CSB10的碳烟排放比柴油的排放值低,而CSB15和CSB20的碳烟排放却比柴油的排放值略高.     

重油掺水乳化稳定性的实验研究

采用机械搅拌+乳化剂的乳化方法和高温静置的检测方法,对重油进行乳化研究。对比了三种复配乳化剂的乳化效果,确定了影响乳化重油稳定性因素的最佳参数。结果表明:TS-2型乳化剂比其他两种乳化剂乳化效果更好;随着乳化剂含量的增加,乳化油的稳定时间先增大后减小;掺水率越大,乳化油的稳定性越差;搅拌速率增大、乳化时间加长、乳化温度升高,有利于乳化油的稳定,但同时能耗也增加。本实验得出乳化重油的理想工艺条件为:TS-2型乳化剂,乳化剂含量约为0.2%,掺水率为10%～20%,搅拌速率为700～900r/min,乳化时间为30min左右,乳化温度为70～80℃。     

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。     

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。     

微乳化生物柴油的制备及其性能研究

微乳化生物柴油是一种比生物柴油更节能环保的绿色能源,其工业化应用有重大经济意义。现有技术中微乳化生物柴油研究存在稳定性差、保存周期短等缺点,本研究的目的是提供一种透明、稳定、燃烧热值高的微乳化生物柴油。通过对非离子型表面活性剂EL12、两性离子表面活性剂卵磷脂和阳离子表面活性剂氯化十六烷基吡啶的复配,发现:1.3%EL12,0.7%卵磷脂和0.5%氯化十六烷基吡啶复配的微乳化生物柴油具有较好的稳定性,其燃烧热值高于纯生物柴油,且其粘度、pH值、氧化安定值等物理特性符合国家柴油机燃料调和用生物柴油标准。     

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.     

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。     

不同类型乳化剂复配在微乳化生物柴油中的研究

采用油酸和二乙醇胺进行酰胺化反应,得到油酸二乙酰胺乳化剂。当油酸与二乙醇胺摩尔比为1∶1.2时,反应得到的合成产物——油酸二乙酰胺,对生物柴油微乳化效果最佳。通过对油酸二乙酰胺与不同碳链数的醇类助乳化剂以及不同类型的表面活性剂(如NP-4,LAS,Span80,Tween80和CTAB等)进行复配,结果表明,质量分数为3.24%的ODEA,2.16%的NP-4和0.6%的正丁醇复配的乳化剂具有最佳的微乳化效果。动态光散射粒径分析结果表明,制备的微乳液平均粒径为18 nm,微乳化生物柴油的颜色透明,稳定性良好。     

生物燃油/柴油乳化燃油的理化特性研究

该研究所用生物燃油是在东北林业大学生物质能中心自主研发的ZKR-200装置上,以各种农业秸秆、废弃木质材料等生物质为原料,经过闪速热裂解而制成的.将不同体积比的生物燃油与柴油在加入少量乳化剂的情况下进行乳化,并对直接影响柴油机性能及燃油的使用、存储和运输的几种基本物理化学性质(密度、粘度、闪点等)进行测试,并用752型紫外可见光分光光度计和莱克显微镜研究其稳定性,总结出了不同生物燃油含量对乳化燃油物性参数的影响规律.研究结果表明:随着生物燃油掺混比例的增加,乳化燃油的密度、粘度、闪点逐渐增加,PH值与稳定性逐渐降低.这些实验结果将对生物燃油的产业化开发和应用具有一定指导意义.     

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.     

Factors affecting emissions from diesel fuel and water-in-diesel emulsion

The purpose of this research is to investigate the effect of addition of surfactant and water in diesel and to make an emulsified fuel considering the needs for vehicle performance and its cleanest possible operation. The total surfactant concentration in each of the diesel-water emulsion samples studied (span 20, span 80, tween 20, tween 80) is fixed at 1% w/w. The water content is variable at 5–15% w/w and the diesel content is varied from 84 to 94% w/w. Among all the tested nonionic surfactants, tween 80 is found to prominently reduce the carbon monoxide (CO), hydrocarbon (HC), and nitrogen oxide (NOx) emissions. Tween 20 reduced the NOx emission to a greater extent. Diesel emulsion with a fixed ratio of span 80 and tween 80 (1:1) efficiently reduced the overall emissions as compared to diesel alone. The developed diesel emulsion employed with nonionic surfactants clearly reduced the harmful engine emissions such as CO, HC, and NOx, signifying them as a future potential emulsifier in diesel fuel emulsion.     

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.     

Stabilization performance of methanol-diesel emulsified fuel prepared using an impinging stream-rotating packed bed

A new continuous process for preparing methanol–diesel oil emulsified fuel is proposed using an impinging stream–rotating packed bed. The combustion of methanol–diesel oil emulsified fuel is significantly affected by its stability. Thus, the stabilization of the methanol–diesel oil emulsified fuel was investigated by varying numerous factors, including high-gravity factor, impinging distance, hydrophilic-lipophilic balance value, liquid flow rate, co-surfactants, content of methanol and emulsifier, and so on. The stabilized time and size of dispersed phase of methanol-diesel oil emulsified fuel were 762 h and 12 μm separately at the operating conditions of liquid flow rate of 70 L/h, an impinging distance of 30 mm, a hydrophilic–lipophilic balance value of 5.4, a high gravity factor of 208.1, a methanol volume content of 15%, co-surfactants of 1-butanol, an emulsifier amount of 3%, and consecutive recycle time of 3. The proposed technology can be applied in industries because of the use of relatively less emulsifier as well as its continuity, processing efficiency, and ease of application in large-scale production.     

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。     

Study on the spray characteristics of methyl esters from waste cooking oil at elevated temperature

In Taiwan, millions of tons of waste cooking oil are produced each year, and less than 20% of it, about 150,000 ton/a, is reclaimed and reused. Most waste oil is flushed down the drain. Utilizing waste cooking oil to make biodiesel not only reduces engine exhaust gas pollution, but also replaces food-derived fuels, and reduces ecologic river pollution. This study employed two-stage transesterification to lower the high viscosity of waste oil, utilized emulsion to reduce the methyl ester NOx pollution, and used methanol to enhance the stability and viscosity of emulsified fuel. To further analyze spray characteristics of fuels, this experiment built a constant volume bomb under high temperature, used high speed photography to analyze spray tip penetration, spray angle, and the Sauter mean diameter (SMD) of fuel droplets, and compared the results with fossil diesel. The experimental results suggested that, two-stage transesterification can significantly lower waste oil viscosity to that which is close to fossil diesel viscosity. At a temperature above 300 °C, waste cooking oil methyl esters had a water content of 20%, spray droplet characteristics were significantly improved, and NOx emission dropped significantly. The optimal fuel ratio suggested in this experiment was waste cooking oil methyl ester 74.5%, methanol 5%, water 20%, and composite surfactant Span–Tween 0.5%.     

Preparation and properties of methanol–diesel oil emulsified fuel under high-gravity environment

A new process for preparation of methanol–diesel emulsified fuel with a rotating packed bed is proposed. The influence of additive amount, methanol content, rotational speed, liquid flow rate of diesel on the rheological characteristics, surface tension and stabilization was discussed. The result showed that the emulsified fuel appeared as proximately Newtonian behavior. The rheological characteristics of the emulsions were significantly dependent on the percentages of surfactants and methanol. The surface tension decreased obviously with the increase of the surfactants amount. With higher additive amount, lower methanol content, higher rotational speed and higher liquid flow rate, the methanol–diesel emulsified fuel showed better stabilization. Comparison with intermission operation, the stabilization of the emulsified fuel was achieved in 32 days with consecutive recycle of 3 times under the high-gravity fields. This method has potential application in industrial fields for its low surfactants, continuity, efficient processing and the ease of scaling-up.     

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.     

柴油机燃用二甲醚-乳化柴油混合燃料的排放试验研究

研究了在柴油机上燃用二甲醚(DME)-乳化柴油混合燃料的排放特性,分析了在乳化柴油中添加DME能降低柴油机废气排放的机理,并且与燃用柴油以及乳化柴油时的排放效果进行了比较。研究结果表明:在乳化柴油中添加10%含量的DME能显著降低NOx和烟度的排放,尤其是在高负荷时,能明显降低HC和CO的排放。与燃用乳化柴油相比,即使在部分负荷时,也不会对NOx排放产生不良的影响。