Preparation and emission characteristics of ethanol-diesel fuel blends

The preparation of ethanol-diesel fuel blends and their emission characteristics were investigated. Results showed the absolute ethanol can dissolve in diesel fuel at an arbitrary ratio and a small quantity of water(0.2%) addition can lead to the phase separation of blends. An organic additive was synthesized and it can develop the ability of resistance to water and maintain the stability of ethanol-diesel-trace amounts of water system. The emission characteristics of 10%, 20%, and 30% ethanol-diesel fuel blends, with or without additives, were compared with those of diesel fuel in a direct injection(DI) diesel engine. The experimental results indicated that the blend of ethanol with diesel fuel significantly reduced the concentrations of smoke, hydrocarbon(HC), and carbon monoxide(CO) in exhaust gas. Using 20% ethanol-diesel fuel blend with the additive of 2% of the total volume, the optimum mixing ratio was achieved, at which the bench diesel engine testing showed a significant decrease in exhaust gas. Bosch smoke number was reduced by 55%, HC emission by 70%, and CO emission by 45%, at 13 kW/1540 r/min. However, ethanol-diesel fuel blends produced a few ppm acetaldehydes and more ethanol in exhaust gas.

Effect of <i>γ</i>-Valerolactone Blending on Engine Performance, Combustion Characteristics and Exhaust Emissions in a Diesel Engine

γ-valerolactone (GVL) is a C5-cyclic ester that can be produced from biomass providing a potentially renewable fuel for transportation and feedstock for the chemical industry. Experiments were performed with fossil diesel (D), D + biodiesel (BD) and D + BD + GVL blends. A four-cylinder, turbocharged direct injection diesel engine was used for the tests. The engine was coupled to a dynamometer to vary the load. CO, NOx, THC and smoke emissions were measured by using a multi-channel gas analyzer. Combustion characteristics were assessed by in-cylinder pressure data with respect to crank angle and the derived heat release rates. Compared with D, and D + BD blends, addition of GVL had relatively little effect on engine performance and NOx emission, but reduced the exhaust concentration of CO, unburned fuel and smoke significantly. The smoke reduction is particularly notable in view of the very recent suggestion that black carbon is the second most important greenhouse gas in the atmosphere next to carbon dioxide. No diesel engine study with GVL has been reported so far.

Experimental Study on Performance and Combustion Analysis of a Diesel Engine Fueled with Diesel and Jatropha Oil Blended with Heptane

This work focuses on blending Jatropha oil with diesel fuel and heptane to improve its physico-chemical characteristics for production of blends and their use as fuel in a diesel engine. The influence of the heptane content was evaluated by comparing the results obtained from the engine (performance and combustion parameters) with those of the diesel fuel and straight Jatropha oil. The results obtained show an improvement in engine performance especially at low loads. Specifically, a reduction in the specific fuel consumption of the engine is obtained when the heptane content in the mixture is around 10% compared to that obtained with pure Jatropha oil. The best results were obtained with the blend containing 70% Jatropha oil, 20% diesel fuel and 10% heptane (J70G20H10). Overall engine efficiency and exhaust gas temperatures are comparable for all fuels tested. Engine combustion parameters are improved with J70G20H10. The results obtained with J70G20H10 are close to those of the engine operating on diesel fuel. The cyclic dispersion is low with coefficients of variation of the indicated mean effective pressure (COVIMEP) whose values are less than 10%. The lowest values of the COVIMEP are obtained with the blend J70G20H10.

Comparative Study of Performances of a Single-Cylinder Diesel Enginefueled with Pure Diesel and Blends of Biodiesels/Pure Diesel

In this study, the principal objective is to compare the performances of an air-cooled one cylinder, four-stroke direct injection diesel engine using the blends (5% by volume B5, 10% by volume B10) of diesel and biodiesels derived respectively from palm oil, castor oil and raphia sese De Wild oil with pure diesel. All the biodiesels used in this work come from the plant species of the democratic republic of Congo as listed above. The engine performances (power, torque and brake specific consumption) at different engine speeds were determined at both full and partial loads. According to experimental results, the increments in the power output and torque when the mixtures of diesel and biodiesels were used and were observed. On the other side, the specific fuel consumption of the mixtures is higher than that of pure diesel although the calculated lower heating values are almost within the same range for the all studied fuels. Finally, in partial load 1/1, pure diesel blended with biodiesels B5 derived from castor oil presented high specific brake consumption values compared to the other fuels while B10 from the same oil presents low brake specific consumption values for power greater than 3.2 kW.

Dispersion Performance of Methanol-Diesel Emulsified Fuel Prepared by High Gravity Technology

A new continuous process for preparing methanol-diesel emulsified fuel with an Impinging Stream-Rotating Packed Bed is proposed. The droplet size of dispersed phase(methanol) of the emulsified fuel has a significant effect on the combustion of methanol-diesel emulsified fuel. In this paper, the methanol-diesel emulsified fuel uses diesel as the continuous phase and methanol as the dispersed phase. The Sauter mean diameter of the dispersed phase of methanol-diesel emulsified fuel was characterized with microphotography and arithmetic method. The experimental result showed that the Sauter mean diameter of the dispersed phase, which was decreased with the augmentation of the high gravity factor, liquid flow rate and emulsifier dosage, was inversely proportional to the methanol content. The Sauter mean diameter of the dispersed phase can be controlled and adjusted in the range of 12—40 μm through the change of operating conditions. The correlative expressions of the Sauter mean diameter of emulsified fuel were obtained and the calculated values agreed well with the experimental values.

同牌号油品不同密度差值范围对油品调和影响的探讨

通过实验室模拟试验和石油库油罐混调试验,分别对汽油和柴油的不同密度差值范围的油品混调时呈现的分层现象进行了试验和分析,结果表明:随着密度差值范围的增大,油品的相溶区域在不断收缩变窄,相溶区域内的密度差幅度也在增大,密度分布分层现象也越来越严重。汽油组的硫含量和辛烷值指标数据以及柴油组的硫含量和闪点指标数据都是同步随着油品混合状态进行分布。为此,建议成品油销售企业制定调和方案时:油品密度差值范围在0~2kg/m^(3)时,大部分的混合区域能呈现混溶状态,可进行调和;密度差值范围在2~4kg/m^(3)时,相溶区域逐渐缩减,分层趋势逐渐显现,可进行调和,但需将管控等级设为中风险级,应做好调和后的取样监测工作;密度差值范围大于4kg/m^(3)后,相溶区域集中在油品交界区域内,已呈现明显的分层现象,管控等级为高风险级,不建议进行调和。

催化裂化装置掺炼直馏柴油效果分析

针对催化裂化装置掺炼直馏柴油进行了分析。某石化公司在降低柴汽比过程中,2套催化裂化装置掺炼了常减压装置10%的直馏重柴油,在确保质量合格及操作参数没有大幅度变化的情况下,2套催化装置汽油收率提高了0.5%~3%,液化气收率提高了0.3%~1%,柴油收率降低了0.5%~2.5%,明显降低了柴汽比,为后续装置进行直馏柴油掺炼累部分操作经验,同时为全厂降低柴汽比积累了数据。

A Comparative Study of Thumba Seed Bio Diesel

Biodiesel is considering a clean-burning fuel produced from non edible vegetable oils, or animal fats. It is produced by transesterification of oils with short-chain alcohols or by the esterification of fatty acids. In the present context, biodiesel is an alternative eco friendly diesel fuel. Keeping this in view, an attempt has been made through the experiment of Thumba blended biodiesel on CI engine in laboratory and analyzes its properties and characteristic compare with other biodiesel oils. Five blends B05, B10, B15, B20 and B25 of thumba seed oil biodiesel were papered and it performance was evaluated with 7HP four-stroke diesel engine. The performance of thumba seed oil biodiesel were compared with biodiesel prepared by mustard, castor and Jatropha seed oil with same blends.

掺混比例对航空煤油/柴油的着火和碳烟排放影响

航空煤油/柴油掺混作为一种典型的宽馏程燃料,具有提升着火能力、改善低温冷起动并对柴油机结构可靠性影响较小等潜在性能.基于电加热定容燃烧弹,耦合纹影法、广域低通化学发光法和高频背光消光法等光学诊断方法,研究了不同航空煤油掺混比例对航空煤油RP-3/柴油掺混燃油喷雾、着火和碳烟排放特性的影响.结果表明:在航空煤油中掺烧柴油,有利于提高掺混燃油的着火能力,但同时也会提高碳烟排放,产生明显的红外信号.随着柴油掺混比例的增加,冷态喷雾体积几乎没有变化,但在高温蒸发环境下,喷雾锥角及体积均略微下降.添加25%(体积分数)的柴油可明显缩短着火滞燃期,且碳烟面积和碳烟质量规律与纯煤油相近,随着柴油组分的进一步增加,碳烟面积和碳烟质量都相应明显增加.此外,掺混25%柴油的航空煤油掺混燃油,可大幅提高燃油的着火性能,且碳烟排放维持在较低水平;航空煤油中添加较少比例的柴油适合在航空发动机中使用,从而成为一种比纯航空煤油更有潜力的单一燃料.

掺烧不同比例乙醚对船用柴油机燃烧和排放性能的影响

为研究掺烧不同比例的乙醚对柴油机燃烧及排放特性的影响,以4190Z L C-2型船用中速机为研究对象,利用AVL_FIRE仿真软件构建燃烧室高压循环模型,在全负荷工况下对比实测与仿真缸压和放热率曲线,验证模型的准确性。在全负荷工况下,通过仿真模拟实验,在柴油中分别掺混体积分数为0%、5%、10%、15%的4种比例的乙醚,研究其对柴油机燃烧和排放特性的影响。结果表明:与燃烧纯柴油相比,使用柴油-乙醚混合燃料,缸内最大爆发压力和缸内最高温度均有所下降,对应的曲轴转角也稍有延后。增加乙醚的掺混比例,CO和NO的排放量均呈现降低趋势,碳烟排放略有增加。在反应过程中,乙醚加入延长了混合燃料的滞燃期,油气混合更加充分,放热过程稳定,提升柴油机的稳定性。当乙醚掺混体积分数为15%时,NO排放量较原机降低12.7%,CO排放量降低7.8%,碳烟排放量增大10.7%。

微界面强化混合柴油加氢精制中试研究

基于微界面强化技术,以混合柴油为原料,在催化剂装填量为2 L的上行式固定床装置上开展了柴油加氢精制中试研究。考察了反应压力、反应温度、V(氢)/V(油)和空速等工艺参数及不同类型催化剂对微界面强化柴油加氢精制脱硫脱氮性能的影响。研究结果表明,在工艺条件考察范围内微界面强化加氢脱硫效果明显优于常规上行式反应器,随着生成油中w(硫)的降低,2者差异程度缩小。以w(硫)为1.58%的混合柴油为原料,采用HRC-1催化剂,与常规上行床柴油加氢相比,脱硫率为99.75%时,微界面强化加氢的反应压力可降低3 MPa以上;在反应压力高于5.0 MPa时,微界面强化加氢脱氮率大于98.2%。以w(硫)为1.02%的混合柴油为原料,采用HRC-2和HRC-3级配催化剂,在空速为0.8 h_(-1)、反应压力5.7 MPa、反应温度365℃的条件下,V(氢)/V(油)≥500时,微界面强化加氢生成油中w(硫)等主要指标均可满足国Ⅵ柴油标准要求。该工艺可为中低压下微界面强化混合柴油加氢工业放大提供参考。

催化柴油掺炼比对柴油加氢工艺的影响

目的考查催化柴油掺炼比对混合柴油加氢工艺的影响。方法针对某炼厂物料平衡的需要及柴油加氢工业装置提高催化柴油掺炼比的需求,以混合柴油的加氢工艺为研究对象,在加氢中试装置上考查催化柴油的掺炼比对加氢工艺参数(平均反应温度)、产品分布和产品性质的影响,建立加氢工艺参数等与催化柴油掺炼比的关联式。结果①随着催化柴油掺炼比的提高,原料的组成更趋重质化、劣质化,加氢难度显著增加;②所建立的精制柴油硫含量、平均反应温度与催化柴油掺炼比的关联式可在一定范围内指导工艺参数的调整;③在同等条件下,随着催化柴油掺炼比的提高,混合柴油的转化率快速降低。综合考虑催化剂寿命、多产优质重整原料的需求以及兼产3号喷气燃料的要求,将催化柴油的掺炼比调整至30%左右较为合适。当产品性质有余量时,掺炼比可适当提高,同时在工业装置上完成验证。结论明确了劣质原料掺炼比对平均反应温度等加氢工艺参数以及加氢裂化产品分布和产品性质的影响,可为同类工业加氢装置掺炼劣质原料提供工业运行实例的参考。

柴油机燃用菜籽油-柴油混合燃料的试验研究

文章在一台双缸直喷柴油机上开展了燃用菜籽油-柴油混合燃料时的发动机性能、燃烧和排放特性研究,并与燃用柴油时相比较。研究结果表明:当菜籽油的掺混比(体积分数)不大于20%时,混合燃料的运动粘度和密度接近于柴油;在低负荷工况下,燃用混合燃料时的燃烧开始时间与柴油几乎相同,但缸内压力峰值和放热率相对较高;在高负荷工况下,燃用混合燃料时的燃烧开始时间略早于柴油,特别是VD50;在低负荷工况下,燃用VD50时的燃油消耗率最高,有效热效率最低;随着发动机负荷的逐渐增加,燃用混合燃料与柴油时的燃油油耗率差异逐渐减小,有效热效率也不断提高;在低负荷工况下,燃用混合燃料时的碳烟排放量较高,高负荷时则与之相反;在低负荷工况下,燃用混合燃料时的NOx排放量略低于柴油,高负荷时则几乎相同;在整个负荷范围内,燃用混合燃料时的CO和HC排放量均较高。

定容弹内柴油/丁醇混合燃料燃烧特性研究

In this paper,the spray and combustion characteristics of diesel/butanol-blended fuels were studied within a high-temperature and high-pressure constant volume chamber equipped with a single-hole injector.Two blends with 80%diesel/20%butanol and 60%diesel/40%butanol mixed by volume were tested in this study.The pure diesel B0 was also tested here as a reference.The spray penetration,flame lift-off length,and soot optical thickness were obtained through high-speed schlieren imaging,OH*chemiluminescence,and diffused back-illumination extinction imaging technique,respectively.The thermogravimetric curves of different fuels were obtained through a thermogravimetric analyzer.The results showed that butanol/diesel blends presented a longer ignition delay(ID)and flame lift-off length compared with pure diesel,and such finding was mainly caused by the lower cetane number and higher latent heat of vaporization of n-butanol.With the increase in the n-butanol ratio,soot production in the combustion process decreased significantly.Given the shorter ID period,the soot distribution of pure diesel reached a steady state earlier than the blends.

掺混乙醇对菜籽油/柴油混合燃料燃烧及排放特性的影响

为改善发动机燃用高比例生物质混合燃料的性能,在中等比例的菜籽油/柴油混合物(VD50)中分别添加10%、20%和30%体积比的乙醇,在助溶剂的作用下制备了菜籽油/柴油/乙醇混合燃料(VD50E10、VD50E20和VD50E30),并对其主要性能进行测试。在1 800 r/min不同负荷条件下,研究乙醇掺混比对中等比例菜籽油/柴油混合燃料燃烧和排放特性的影响,并将其与柴油进行对比。结果表明,在低负荷时,随着乙醇掺混比的增加,混合燃料的燃烧开始时间延迟,缸内峰值压力和瞬时放热率峰值逐渐减小,其中VD50E30最小;在高负荷时,混合燃料的瞬时放热率峰值增加,VD50E30的缸内峰值压力略高于其他试验燃料,柴油的缸内峰值压力最小。随着乙醇体积分数的增加,混合燃料CO和HC的排放量增加,而碳烟和NOx的排放量减小。在某些负荷工况下,VD50E30的碳烟排放量甚至低于柴油。

脂肪酸型抗磨剂对柴油质量的影响

为提高柴油产品质量,通过调和试验,对柴油在加入脂肪酸型抗磨剂COLI9500(以下简称抗磨剂C)前后的性能变化进行了对比分析。试验结果表明:抗磨剂C的加入可以有效降低柴油的磨痕直径,改善了润滑性能,但同时也造成了柴油酸度的明显升高;抗磨剂C与柴油相容性较好,不会造成柴油总不溶物含量升高。此外,其对柴油的破乳性、流动性以及稳定性无明显影响。

柴油机燃用乙醇柴油燃料的燃烧与排放特性

对燃用多种比例乙醇柴油的柴油机燃烧与排放特性进行了试验研究。测试了 5 %～ 2 5 %乙醇柴油燃料以及柴油和乙醇的基本物理性质 ,在ZS1 1 0 0柴油机上对各种比例的乙醇柴油测试了发动机在主要工况下的性能与排放特性 ,并用光学可视化方法研究了柴油、1 5 %乙醇柴油、1 5 %乙醇柴油加十六烷值改进剂的燃烧过程。

不同配比乙醇柴油混合燃料的经济性和排放性

为了研究乙醇柴油混合燃料的经济性和排放性,该文在双缸直喷式柴油机和在用的柴油轿车上分别进行了发动机台架试验和整车底盘测功机试验。结果表明,在不调整柴油机条件下,使用乙醇柴油混合燃料能够在一定程度上改善发动机燃油经济性和降低排气烟度和NOX排放,但HC排放增加。适当减小供油提前角有利于改善乙醇柴油混合燃料发动机经济性和排放特性。对于试验车辆,燃用E10有利于降低汽车在中、高速时的等速工况燃料消耗量和常温下冷起动后PM、NOX排放量。该研究结果对于改善乙醇柴油混合燃料的燃油经济性和排放性具有实用价值。

乙醇-柴油混合燃料的理化特性研究

对乙醇 柴油燃料直接影响发动机性能和燃料的使用、存储和运输的几种基本物理化学性质进行了研究。通过对不同比例(乙醇含量分别0.2%、0.5%、1%、2%、5%、10%、15%、20%、25%、75%)的混合燃料的密度、粘度、闪点、表面张力、十六烷值、稳定性和磨损性等理化性质的测试和研究,总结出了乙醇含量对混合燃料物性参数的影响规律,归纳出各种参数随温度变化的规律。以密度为特征参数,拟合出混合燃料粘度、表面张力随密度变化的关系,得到了具有较高精度的乙醇 柴油混合燃料的理化特性经验关系式。

柴油机燃用乙醇-柴油含氧燃料时微粒特性的分析

研究了一台增压柴油机燃用乙醇-柴油时的微粒总质量排放及粒径分布特性,并对微粒中可溶性有机物(SOF)、干碳烟(DS)和硫酸盐的质量百分比及SOF中的组分进行了分析.结果表明:使用含氧燃料后柴油机排气烟度大幅度降低而微粒总排放量降低幅度要小一些;微粒中DS排放降低;SOF排放增加,与未燃甲酯的产生导致HC排放增加有关;多环芳香烃比例随发动机负荷增大而减小;含氧燃料使得粒径分布在0.2～0.5 μm范围内的比重在小负荷时降低,大负荷时升高.