酯化烷基化联立提质生物油的燃烧与排放特性

通过催化酯化烷基化联立工艺将生物质热解油提质为高品位燃油(简称提质生物油)。将提质生物油分别以体积分数5%、10%和15%与0^#柴油混合,配制成混合燃油B5、B10和B15,在柴油机上评估其燃烧与排放性能。结果表明：当柴油机工作负荷相同时,随着提质生物油体积分数增加,混合燃油的当量比燃油耗逐渐升高,有效热效率逐渐下降,混合燃油的燃烧始点逐渐提前,滞燃期逐渐缩短,燃烧初期的放热率和缸压峰依次下降,而主燃阶段的放热率和缸压峰依次上升;在低负荷工况时,由于循环喷油量少,缸内的低温抑制了HC、CO的进一步氧化,且不易形成NO_x和碳烟,因此与高负荷工况相比,4种燃油的HC和CO排放特性差异较大,而NO_x和碳烟排放特性差异较小。     

PODE/柴油混合燃料对共轨柴油机燃烧与排放特性的影响

按聚甲氧基二甲醚(PODE)占混合燃料体积分数为10%、20%和30%的掺混比,配制了PODE/柴油混合 燃料。在共轨柴油机上研究了PODE掺混比对PODE/柴油混合燃料燃烧和排放特性的影响。结果表明,在 额定转速100%负荷时,与柴油相比,不同PODE掺混比PODE/柴油混合燃料的滞燃期缩短,缸内最大爆发 压力升高,放热率峰值降低;一氧化碳（CO）体积分数分别降低了13.1%、16.6%和21.3%,未燃碳氢 （HC）体积分数分别降低了17.7%、24.1%和26.2%,排气烟度分别降低了29.6%、44.8% 和75.8% ;但是碳氧化物（NOx）体积分数分别增加了2.0%、7.4%和9.5%;颗粒物数量峰值依次分别增加了16 .8%、30.8%和55.1%。在额定转速25%负荷时,不同PODE掺混比PODE/柴油混合燃料与柴油相比,CO体 积分数分别降低了12.4%、16.3%和20.8%,HC体积分数分别降低了14.5%、21.6%和24.1%,排气烟 度分别降低了28.0%、44.0% 和76.0%,但NOx体积分数分别增加了7.7%、10.4%和16.2%。核模态 颗粒物数量峰值分别增加了143%、269%和335%;而积聚态颗粒物数量峰值分别降低了15.4%、24 .0%和44.5%。     

添加剂对乙醇柴油稳定性及排放性能的影响

在含乙醇质量分数10%和正丁醇质量分数5%的乙醇柴油(简称N5E10)中分别加入不同质量分数的十六烷值改进剂(CN)或消烟剂(XY),考察其对乙醇柴油稳定性的影响,并在YZ4DB3柴油机上分别燃用这些燃料进行台架试验。结果表明,添加CN或XY质量分数分别为01%、03%和05%的N5E10的稳定性良好。与燃用柴油相比,燃用乙醇柴油及含添加剂的乙醇柴油能降低NOx排放和排放气烟度,但CO、HC排放体积分数总体上升高,低负荷时较明显。多数工况下,乙醇柴油中添加十六烷值改进剂可降低柴油机的CO、HC排放和烟度,而柴油机转速对NOx排放的影响明显。乙醇柴油中添加消烟剂可以明显降低柴油机排放气烟度,而CO、HC和NOx的排放受柴油机工况的影响;当转速为1800 r/min时,能降低NOx排放,但会导致HC和CO排放量增加;转速为2900 r/min时,能降低HC和CO排放,但却导致NOx排放增加,甚至超过原机排放。在N5E10燃料中加入质量分数为03%的十六烷值改进剂或05%的消烟剂,可以得到最佳减排效果。     

掺混比对异丁醇-柴油混合燃料性能的影响

在1台增压中冷高压共轨柴油机上,试验探讨了异丁醇-柴油不同掺混比的混合燃料对发动机燃烧过程及性能的影响。结果表明:相同负荷率下,掺混异丁醇降低了燃料热值,发动机燃油消耗率增加;柴油掺混异丁醇后,含氧量增加,可有效抑制碳烟排放,但十六烷值降低。重型柴油机稳态测试循环(ESC-13工况)加权比排放测试发现,掺混10%异丁醇的柴油燃烧产生的微粒比排放最低;同转速小负荷工况下,加大异丁醇掺混比后,混合燃料增高的汽化潜热和低十六烷值共同引起滞燃期延长,使缸内温度降低,CO、HC及微粒排放增加;而大负荷工况下缸内燃烧高循环热量可有效抑制这一趋势,除NOx排放外,其余有害物比排放降低。     

碳酸二甲酯对烷基化汽油燃烧性能的影响

在四缸直列四冲程增压直喷汽油机上,研究了添加体积分数为10%的碳酸二甲酯(DMC)对燃用烷基化汽油在典型工况下发动机性能的影响及其燃烧过程原理。结果表明：在所有工况下,添加DMC后燃油消耗率均有明显增加,增幅最高可达20.53%,有效热效率变化不明显。在外特性工况下,添加DMC对汽油机动力性影响不大,均不超过3%;在稳态工况下,DMC的加入降低了燃料的总碳氢化合物(THC)和氮氧化物(NOx)排放,碳氢化合物(HC)的排放最大降幅为13%,NOx排放最大降幅为32%;在低转速工况下,DMC的添加可引起总颗粒物排放增加,最大增幅为103%,其中核态颗粒物增加是主要因素,最大增幅为113%。燃烧过程分析表明,加入DMC会造成燃烧始点最多推迟1.24° CA,燃烧重心最多推移1.98° CA,燃烧持续期最大延长2.32° CA,从而引起定容性下降,热效率降低,后燃量增加,颗粒物升高,燃烧温度下降,NOx排放降低。     

煤炭间接液化柴油排放特性实验研究

选用宁夏煤业公司煤炭间接液化柴油(间接液化柴油)、中国石油天然气股份有限公司化石柴油(中石油柴油)和中国神华煤制油化工有限公司煤炭直接液化柴油(直接液化柴油)为实验燃料，分别在发动机转速为1 200、1 400、1 700、2 000 r/min条件下对比考察了燃用3种柴油后CO、HC、NO和烟度等的排放特性。结果表明：燃用间接液化柴油时，污染物CO排放量最低；与中石油柴油相比，燃用间接液化柴油NO、HC排放量略低，但在转速为2 000 r/min的中低负荷下，燃用间接液化柴油的HC排放量比中石油柴油略高；在上述4个转速条件下，燃用间接液化柴油CO排放量平均下降率为30%左右；HC排放量平均下降率为24%左右；NO排放量平均下降率为12%左右；烟度平均上升率为4%左右。综上所述，燃用间接液化柴油具有良好的环保性。     

聚甲氧基二甲醚-柴油混合燃料对柴油机燃烧与排放的影响

在柴油中掺混体积分数为5%、10%和15%的聚甲氧基二甲醚(PODE3 8)得到PODE3 8 柴油混合燃料,利用热重分析仪在氧气气氛下对这些混合燃料样品进行热分析,考察其挥发和氧化特性,计算热分析参数;在柴油机上考察它们的燃烧与排放性能,并与柴油对比。结果表明,随掺混比的增加,3种PODE3 8 柴油混合燃料的起始质量损失温度相对于柴油降低了34℃、56℃和70℃,起始燃烧温度降低了64℃、118℃和172℃,热稳定性降低,同时综合燃烧特性指数提高。在额定工况下,与燃用柴油相比,柴油机燃用PODE3 8 柴油混合燃料时,滞燃期缩短,缸内最高压力略有提高;在预混燃烧阶段放热率峰值有所降低,在扩散燃烧阶段放热率峰值提高;比油耗相对于柴油分别增加08%、32%和85%,但有效热效率提高28%、42%和31%;CO排放分别降低了118%、140%和188%,HC排放分别降低了192%、268%和217%,排气烟度分别降低了252%、308% 和321%,NOx排放基本不变。     

代用燃料在柴油机中的应用研究。

本文对植物油,生物柴油,乳化油,乙醇／柴油等的制备和理化特性进行了研究。通过柴油机台架试验,研究了柴油机燃用生物柴油、乙醇／柴油、微乳燃油的排放特性。对比试验表明：生物柴油CO,碳氢（HC）和颗粒物（PM）的比排放下降幅度分别为34．6％,40．2％和28．9％,但NOx比排放增加了6．63％;柴油机燃用乙醇／柴油时,NOx和碳烟排放降低,但总碳氢（THC）和CO排放要略高于柴油;柴油机燃用微乳柴油时,NOx和碳烟的排放下降,HC和CO排放升高,在高负荷时柴油机燃烧微乳柴油具有一定节油效果。用电镜扫描对柴油机排气PM进行粒径测量表明：乙醇／柴油的排气颗粒物粒径要大于柴油,但是其含碳量低,对人体的危害要小。     

喷油参数对PODE/柴油混合燃料燃烧污染物排放的影响

以柴油(P0)、聚甲氧基二甲醚(PODE)/柴油混合燃料(P10和P20)为对象,在高压共轨柴油机上,考察其在不同喷油压力和喷油正时下的燃烧排放特性及颗粒物排放规律。结果表明：随混合燃料中PODE体积分数的增加,燃料燃烧缸内压力和放热率峰值有所降低;随着喷油压力的提高,3种燃料的CO、碳氢化合物(HC)和烟度排放均明显下降,NO_x排放有所上升,排气颗粒的峰值数量浓度不断降低,其中积聚态颗粒占比降低,核态颗粒占比增加;推迟喷油可以降低NO_x排放,但会增加CO、HC和烟度排放,颗粒的数量浓度有所增加;3种燃料中,P10燃料NO_x生成量和排气颗粒的几何平均直径受喷油压力和喷油正时影响最小。     

二甲氧基甲烷／柴油调合物可成为控制排放的低成本途径

西安交通大学的研究人员研究了二甲氧基甲烷（DMM）／柴油调合物用作直喷式（DI）柴油机燃料时的燃烧性能和排放状况,DMM含量在0～50％范围。研究结果表明,二甲氧基甲烷／柴油调合物可成为控制排放的低成本途径。在燃料喷射系统和发动机无改变的情况下,烟尘和CO排放降低,NOx排放几乎不改变,而烃类（HC）排放有所增加。燃料消耗较高（DMM热值比柴油稍低）,而热效率稍有提高。柴油发动机燃用30％DMM调合油时,燃料效率和排放是满意的。这项研究成果已于2008年11月14日在美国化学学会《能源与燃料》上发表。     

Performance and emission characteristics of a diesel engine using Calophyllum Inophyllum biodiesel blends with TiO2 nanoadditives and EGR

An experimental investigation was carried out to evaluate the performance and emission characteristics of a single cylinder diesel engine by using Calophyllum Inophyllum biodiesel blends with TiO₂ nano additives and exhaust gas recirculation (EGR). The Calophyllum Inophyllum biodiesel-diesel blend was prepared by mixing 20% of Calophyllum Inophyllum biodiesel with 80% diesel (B20) in volumetric approach. The TiO₂ nanoparticles were dispersed into a B20 fuel with a dosage of 40?ppm to prepare the B2040TiO₂ fuel sample. The tests were conducted on a diesel engine by using B20, B2040TiO₂, B20?+?20%EGR, B2040TiO₂?+?20% EGR fuel samples at different load conditions. The brake thermal efficiency of B2040TiO₂, B2040 TiO₂?+?20%EGR fuels increased by 3.1%, 2.5%, and decreased by 1.8% for B20?+?20%EGR fuel compared to the B20 fuel at full load condition. The CO and HC emissions were reduced with the addition of TiO₂ nano particles to the B20 fuel and increased with the EGR method compared to the B20 fuel. The smoke emissions were increased by 16.23% and 12% for the B20?+?20%EGR and B2040TiO₂?+?20%EGR fuel samples compared to the B20 fuel at full load condition. The NOx emissions were reduced with the EGR technique and increased with the addition of TiO₂ nanoparticles to the biodiesel blend compared to the B20 fuel. It is concluded that Calophyllum Inophyllum biodiesel blend (B20) with the addition of TiO₂ nano particles and EGR technique exhibits better engine performance and reduced emissions compared to the other fuels.     

Effect of waste cooking-oil biodiesel on performance and exhaust emissions of a diesel engine

The ever increase in global energy demand, consumption of depletable fossil fuels, exhaust emissions and global warming, all these led to search about alternative fuels. Biodiesel was produced from waste cooking-oil by transesterification process. Blends of waste cooking-oil biodiesel and diesel oil were prepared in volume percentages of 10, 20 and 30% as B10, B20 and B30. Biodiesel blends have ASTM standards of physical and chemical characterization near to diesel fuel. Diesel engine performance and exhaust emissions were studied experimentally for burning waste cooking-oil blend with diesel fuel. This experimental was applied on a diesel engine at different engine loads from zero to full load. Thermal efficiencies for waste cooking-oil biodiesel blends were lower than diesel oil. Specific fuel consumptions of biodieselblends were higher than diesel fuel. Higher exhaust gas temperatures were recorded for biodiesel blends compared to diesel oil. CO₂ emissions for waste cooking-oil biodiesel blends were higher than diesel oil. CO, smoke opacity and HC emissions for biodiesel blends were lower than diesel fuel. NO_x emissions for biodiesel blends were higher than diesel fuel.     

Performance and emission characteristics of a stationary diesel engine fuelled by Schleichera Oleosa Oil Methyl Ester (SOME) produced through hydrodynamic cavitation process

In this study, the performance and emission characteristics of biodiesel blends of 10, 20, 30 and 50% from Schleichera Oleosa oil based on hydrodynamic cavitation were compared to diesel fuel, and found to be acceptable according to the EN 14214 and ASTM D 6751 standards. The tests have been performed using a single cylinder four stroke diesel engine at different loading condition with the blended fuel at the rated speed of 1500 rpm. SOME (Schleichera Oleosa Oil Methyl Ester) blended with diesel in proportions of 10%, 20%, 30% and 50% by volume and pure diesel was used as fuel. Engine performance (specific fuel consumption and brake thermal efficiency) and exhaust emission (CO, CO₂ and NOx) were measured to evaluate the behaviour of the diesel engine running on biodiesel. The results show that the brake thermal efficiency of diesel is higher and brake specific fuel consumption is lower at all loads followed by blends of SOME and diesel. The performance parameter for B10, B20, B30 and B50 were also closer to diesel and the CO emission was found to be lesser than diesel while there was a slight increase in the CO₂ and NOx. SOME produced by using hydrodynamic cavitation seems to be efficient, time saving and industrially viable. The experimental results revel that SOME-diesel blends up to 50% (v/v) can be used in a diesel engine without modifications.     

Performance and exhaust emissions of a diesel engine using diesel nanoemulsions as alternative fuels

The aim of this paper is to investigate the effect of water-in-diesel fuel nanoemulsions on diesel engine performance and exhaust emissions of a single cylinder diesel engine at different engine loads. Emulsified diesel fuel was prepared by mixing diesel fuel with surfactant in the percentage of 4, 6, 8 and 10 wt% of the emulsion total weight. Emulsified diesel oils with varying content of water and surfactant concentrations were prepared via the batch method technique. Different concentrations of water as 5, 6 and 7 wt% was gradually added. Effect of water content and surfactant concentration on engine performance parameters and exhaust emissions were investigated. From the obtained results, specific fuel consumptions for water diesel emulsions were reduced by 8% compared to pure diesel fuel at 4 wt% surfactant concentration, 7 wt% water content and engine load of 1 kW. Furthermore, the lowest HC, CO and NOx emissions value of 66, 48 and 32%, respectively were obtained in case of using 6 wt% of surfactant concentration, 7% water content and engine load of 1 kW. The prepared emulsified diesel fuel achieved a higher engine performance and lower exhaust emissions compared to neat diesel fuel.     

Effect of biodiesel fuels on diesel engine emissions

Energy production is heavily dependent on fossil fuels that are not only diminishing, but also are considered the main cause of harmful emissions and global warming. Therefore using vegetable oils such as Jatropha, palm, algae and waste cooking oils as alternative fuels in diesel engines has drawn a great attention. Biodiesel from Jatropha, palm, algae and waste cooking oils has been produced using the transesterification process. Biodiesel from different feedstock is mixed with diesel oil in different proportions e.g. B10 and B20. Biodiesel physical and chemical properties are measured according to ASTM standards. A “single cylinder diesel engine” is employed as the test engine in the present work. Exhaust emissions such as CO, CO₂, NO_x, HC, and smoke are measured and compared with diesel oil. CO, HC, CO₂ and smoke emissions are lower for biodiesel mixtures B10 and B20 (Jatropha, algae and palm) compared “to diesel fuel”. CO₂ emissions from biodiesel blends B10 and B20 produced from waste cooking oil are higher compared to diesel fuel. NO_X emissions from all biodiesel mixtures B10 and B20 increases than diesel fuel for all biodiesel blend B10 and B20.