橡胶籽生物柴油在柴油发动机上的应用研究

以0#轻柴油、-10#军用柴油为对比燃油,对调和生物柴油B5、B20(橡胶籽生物柴油含量分别为5%、20%,常规柴油含量分别为95%、80%)在WD61550柴油发动机上进行适应性研究,考察了柴油机燃用不同燃油时的外特性、负荷特性,测定了功率、扭矩、油耗等性能指标。研究结果表明,发动机使用调和生物柴油的外特性、负荷特性参数变化趋势与所用对比燃油一致;使用调和生物柴油B5时,发动机动力性、经济性与0#轻柴油几乎无区别,与-10#军用柴油相比略有下降;使用B20时,发动机动力性与0#轻柴油、-10#军用柴油相比稍有下降,油耗略有增加。总体来看,在不改变发动机结构情况下,调和橡胶籽生物柴油B5、B20可以替代0#轻柴油。     

新疆生物柴油的产业化研究

在对新疆棉籽油资源,可利用荒山、荒地资源,棉籽生物柴油的理化特性,棉籽生物柴油与0#石化柴油的调和特性及发动机台架测试研究基础上,探讨了新疆发展生物柴油产业化的优势及思路。提出要因地制宜,科学规划专用棉、能源经济林建设,采取“企业＋农户＋科研单位”的紧密协作机制,进行生物柴油与甘油等副产品一体化综合开发,用生物柴油产业标准规范市场行为,完善政策扶持体系,加大科技助推力度,以实现新疆生物柴油的产业化。     

改善菜籽油生物柴油低温流动性能的研究

以国产菜籽油为原料采用碱催化酯交换法合成生物柴油,并测定了其酸值、总甘油含量、碘值、脂肪酸甲酯的分布和红外光谱.首先,考察了4种降凝剂、0号和-20号柴油以及乙醇对纯生物柴油低温流动性能的影响.0号柴油能有效地改善生物柴油黏度,但其低温流动性能随柴油量的增加而变差;-20号柴油和乙醇能显著降低生物柴油的凝点、倾点、冷滤点和黏度;其中有3种降凝剂能有效降低生物柴油的凝点和倾点,2种降凝剂能较好地改善冷滤点.然后,研究了降凝剂对与柴油调和的生物柴油低温流动性能的影响.在与80%柴油调和的生物柴油中再添加降凝剂,不但能显著改善低温流动性能,而且与纯生物柴油相比其黏度也大幅下降.因此,在与柴油调和的生物柴油中添加降凝剂是同时改善纯生物柴油低温流动性能和黏度的好方法.     

生物柴油调和燃料理论热值比对分析

通过酯交换法在实验室制备了小桐子生物柴油、地沟油生物柴油和橡胶籽生物柴油,与0#柴油按照不同体积比配制出36种生物柴油调和燃料。计算生物柴油调和燃料的门捷列夫理论热值和质量分数理论热值,分别与测定热值进行线性拟合,得出最佳理论热值计算方法。结果表明:质量分数理论热值计算方法适用于小桐子生物柴油调和燃料;门捷列夫理论热值计算方法适用于地沟油生物柴油调和燃料;两种方法均适用于橡胶籽生物柴油调和燃料理论热值计算。     

3种生物柴油成品品质及性能评价

对小桐籽油、棉籽油和橡胶籽油制备出的3种生物柴油进行了一系列的分析检测,并对其品质进行了比较和评价.检测结果表明,3种油制得的纯生物柴油除了氧化安定性以外均可达到国家标准,在添加了适量抗氧剂后氧化安定性也可达到国家标准.将上述3种生物柴油与市售0~#柴油按5%、10%、20%的调合比例掺混,调配成B5、B10、B20的调合生物柴油,并对其进行了全项分析检测,在检测过程中发现0#柴油氧化安定性的检测方法并不适用于所有调合生物柴油.     

阴香籽油超声提取及其制备生物柴油的研究

研究了阴香籽油超声提取的最佳条件及其制备生物柴油的工艺。结果表明:阴香籽油的最佳超声提取条件为:以石油醚为提取溶剂,超声功率105 W、提取时间15 min、料液比(种籽质量与提取溶剂体积比)1∶20,阴香籽油的提取率为58.99%;阴香籽油各项理化性质测定结果,酸值25.42 mg KOH/g、碘值3.85 g I2/l00 g、皂化值282 mg KOH/g、折光率1.450 5;其脂肪酸的主要成分有癸酸(10.38%)、月桂酸(84.21%)、十四碳酸(1.38%)、棕榈酸(0.47%)、油酸(1.48%)、亚油酸(0.91%)、亚麻酸(0.39%)、棕榈油酸(0.012%)、硬脂酸(0.090%)、花生酸(0.046%)等10种脂肪酸组成;脂肪酸的碳链长度在C10~C20之间,其中C12~C20的脂肪酸占89.62%,亚麻酸质量分数为0.39%,小于12%,而且不含十八碳四烯酸;阴香籽油的理化性质、脂肪酸组成及质量分数符合制备生物柴油的标准。通过L9(34)正交试验确定阴香籽油制备生物柴油的最佳工艺条件为:油醇物质的量比1∶6、KOH催化剂1.0%、反应时间2 h、反应温度60℃,转化率为96.38%,并且测定的阴香籽油生物柴油的各项指标,接近我国0#柴油、GB/T 20828—2007《柴油机燃料调和用生物柴油》,阴香籽油生物柴油是一种安全、绿色的生物能源。     

两级双液相萃取棉籽联产生物柴油和无毒棉粕

采用两级双液相萃取棉籽联产生物柴油和无毒棉粕。与一步双液相萃取法处理棉籽技术相比,该法在保持甲醇总量不变的基础上,将双液相萃取分为两级进行,二级萃取用的甲醇在完成了萃取功能以后再作为酯交换反应原料使用,不再需要重新加入新鲜的甲醇进行反应,减少了甲醇用量和溶剂再生的负荷。得出酯交换反应的最佳条件为:一级萃取甲醇用量为甲醇总量的60%,催化剂用量为棉籽油质量的1.1%,反应温度60℃,反应时间120 min。在最佳反应条件下,生物柴油产物中脂肪酸甲酯含量可达98.8%;萃取棉粕中游离棉酚含量为0.013%,符合美国国家棉籽产品协会的贸易标准,可用作动物饲料等。     

H_2SO_4一步法催化棉籽酸化油制备生物柴油的工艺研究

采用传统液体酸浓H2SO4一步法催化棉籽酸化油与甲醇的酯化反应制备生物柴油,考察了醇油质量比、催化剂用量、反应时间对酯化率的影响。结果表明,酯化反应最佳反应条件为:醇油质量比1∶1,催化剂用量2.5%(占油质量),反应时间10 h;在此条件下酯化率为92.17%。制得的生物柴油与我国0#柴油标准(GB/T 19147—2003)的主要性能指标接近。     

棉籽生物柴油及其调和油理化性能的研究

试验采用固体碱催化棉籽油制取生物柴油，将生物柴油与0#石化柴油按体积比配成B5、B10、B20、B30、B40、B50系列调和油，测定并比较了0#石化柴油、生物柴油及其调和油的密度、闭口闪点、硫含量、残炭、灰分、酸值等理化性能，初步探讨了生物柴油含量对调和油性能的影响规律，结果表明，B5、B10、B20调和油闪点、硫含量等性能更优，这对于生物柴油的开发应用具有极其重要的现实意义和应用前景。     

化学法生物柴油生产工艺改进研究

以棉籽油为原料,探讨了化学法制取生物柴油过程中以吸附剂处理替代水洗干燥的精制工艺.通过正交试验研究了吸附剂处理对生物柴油质量的影响.结果表明:在吸附剂用量、混合时间和吸附温度3个因素中,吸附剂用量影响最大,其次为混合时间,吸附温度的影响最小.用1.5%和2%吸附剂在70 ℃下搅拌处理20～25 min后的产品质量明显强于吸附剂其他处理方式得到的生物柴油产品质量,主要指标能达到中国生物柴油国家标准<柴油机燃料调合用生物柴油(BD100)>的相关要求.     

混合燃料中生物柴油掺混比例对发动机性能影响的研究

为了研究高原环境下生物柴油-乙醇-柴油混合燃料中生物柴油对柴油发动机性能的影响,选用纯柴油、B15E3(生物柴油体积分数为15%,乙醇体积分数为3%和柴油体积分数为82%)和B25E3(生物柴油体积分数为25%,乙醇体积分数为3%和柴油体积分数为72%)在柴油发动机YN30CR上进行试燃,在最大扭矩转速工况下比较3种燃料的燃烧性、经济性和排放性差异。结果表明:燃烧混合燃料的发动机动力性下降,B25E3下降明显,缸内压力峰值下降1 MPa,压力升高率峰值下降0.14 MPa/°CA;燃烧B15E3和B25E3的瞬时放热率峰值较纯柴油低4.8%、5.6%;当量燃油消耗量低于纯柴油,燃油经济性有一定改善;中低负荷下,纯柴油当量燃油消耗量最高,B25E3的当量燃油消耗量低于B15E3,高负荷下,燃烧B25E3的当量燃油消耗量稍高于B15E3;燃用B15E3和B25E3后,碳烟排放低于燃烧纯柴油,B25E3改善幅度大于B15E3,随着负荷的增加,碳烟排放性的改善较为明显。     

Evaluation of the Impacts of Biodiesel and Second Generation Biofuels on NO(x) Emissions for CARB Diesel Fuels

The impact of biodiesel and second generation biofuels on nitrogen oxides (NO(x)) emissions from heavy-duty engines was investigated using a California Air Resources Board (CARB) certified diesel fuel. Two heavy-duty engines, a 2006 engine with no exhaust aftertreatment, and a 2007 engine with a diesel particle filter (DPF), were tested on an engine dynamometer over four different test cycles. Emissions from soy- and animal-based biodiesels, a hydrotreated renewable diesel, and a gas to liquid (GTL) fuel were evaluated at blend levels from 5 to 100%. NO(x) emissions consistently increased with increasing biodiesel blend level, while increasing renewable diesel and GTL blends showed NO(x) emissions reductions with blend level. NO(x) increases ranged from 1.5% to 6.9% for B20, 6.4% to 18.2% for B50, and 14.1% to 47.1% for B100. The soy-biodiesel showed higher NO(x) emissions increases compared to the animal-biodiesel. NO(x) emissions neutrality with the CARB diesel was achieved by blending GTL or renewable diesel fuels with various levels of biodiesel or by using di-tert-butyl peroxide (DTBP). It appears that the impact of biodiesel on NO(x) emissions might be a more important consideration when blended with CARB diesel or similar fuels, and that some form of NO(x) mitigation might be needed for biodiesel blends with such fuels.     

Brassica carinata as an alternative oil crop for the production of biodiesel in Italy: engine performance and regulated and unregulated exhaust emissions

A comparison of the performance of Brassica carinata oil-derived biodiesel with a commercial rapeseed oil-derived biodiesel and petroleum diesel fuel is discussed as regards engine performance and regulated and unregulated exhaust emissions. B. carinata is an oil crop that can be cultivated in coastal areas of central-southern Italy, where it is more difficult to achieve the productivity potentials of Brassica napus (by far the most common rapeseed cultivated in continental Europe). Experimental tests were carried out on a turbocharged direct injection passenger car diesel engine fueled with 100% biodiesel. The unregulated exhaust emissions were characterized by determining the SOOT and soluble organic fraction content in the particulate matter, together with analysis of the content and speciation of polycyclic aromatic hydrocarbons, some of which are potentially carcinogenic, and of carbonyl compounds (aldehydes, ketones) that act as ozone precursors. B. carinata and commercial biodiesel behaved similarly as far as engine performance and regulated and unregulated emissions were concerned. When compared with petroleum diesel fuel, the engine test bench analysis did not show any appreciable variation of output engine torque values, while there was a significant difference in specific fuel consumption data at the lowest loads for the biofuels and petroleum diesel fuel. The biofuels were observed to produce higher levels of NOx concentrations and lower levels of PM with respect to the diesel fuel. The engine heat release analysis conducted shows that there is a potential for increased thermal NOx generation when firing biodiesel with no prior modification to the injection timing. It seems that, for both the biofuels, this behavior is caused by an advanced combustion evolution, which is particularly apparent at the higher loads. When compared with petroleum diesel fuel, biodiesel emissions contain less SOOT, and a greater fraction of the particulate was soluble. The analysis and speciation of the soluble organic fraction of biodiesel particulate suggest that the carcinogenic potential of the biodiesel emissions is probably lower than that of petroleum diesel. Its better adaptivity and productivity in clay and sandy-type soils and in semiarid temperate climate and the fact that the performance of its derived biodiesel is quite similar to commercial biodiesel make B. carinata a promising oil crop that could offer the possibility of exploiting the Mediterranean marginal areas for energetic purposes.     

燃用掺混小比例生物柴油对船舶柴油机性能的影响

为探究生物柴油在船舶柴油机上的适用性,基于六缸中速柴油机试验台架,在不同负荷推进特性工况下,对燃用0#柴油、B10生物柴油柴油机的动力性能、经济性能、振动特性和缸内燃烧特性进行对比分析。结果发现：与0#柴油相比,燃用B10生物柴油柴油机的输出功率和耗油量基本不变,耗油率有所升高,但随着负荷的升高有所改善,燃用B10生物柴油使得在25%负荷工况下的柴油机缸盖振动烈度下降,50%、75%、90%、100%负荷工况下的柴油机缸盖振动烈度稍有上升,不同负荷工况下的机体振动烈度均下降;从振动功率谱密度可以看出,两种燃油在不同负荷下低频段的振动响应相似,但高频段处振动响应存在差异;对两种燃油的缸内压力和压力升高率曲线的分析可知,燃用B10生物柴油可以使缸内压力峰值和最大压力升高率升高,燃烧反应速度加快。综上,B10生物柴油在不同负荷工况下动力性能、经济性能、振动特性和缸内燃烧特性方面均表现良好,在船舶柴油机上具有较好的应用前景。     

生物柴油的燃烧及排放特性研究

在一台四冲程直喷式柴油机上对比研究不同喷油策略对鱼油乙酯生物柴油混合燃料燃烧和排放特性的影响。发动机转速固定在1 500 r/min,喷油正时分别在21、24、27°CA BTDC的不同负荷下,使用的6种燃料为柴油及B20、B40、B60、B80、B100的鱼油乙酯生物柴油混合燃料。结果表明:在不同喷油正时、不同负荷下,生物柴油与柴油相比,发动机的氮氧化物和碳烟排放最大降幅为17.9%和55.38%;鱼油制取的生物柴油导致气缸压力峰值、放热率和最大压力升高率均低于柴油,碳氢化合物、一氧化碳排放降低。     

Characteristics of SME biodiesel-fueled diesel particle emissions and the kinetics of oxidation

Biodiesel is one of the most promising alternative diesel fuels. As diesel emission regulations have become more stringent, the diesel particulate filter (DPF) has become an essential part of the aftertreatment system. Knowledge of kinetics of exhaust particle oxidation for alternative diesel fuels is useful in estimating the change in regeneration behavior of a DPF with such fuels. This study examines the characteristics of diesel particulate emissions as well as kinetics of particle oxidation using a 1996 John Deere T04045TF250 off-highway engine and 100% soy methyl ester (SME) biodiesel (B100) as fuel. Compared to standard D2 fuel, this B100 reduced particle size, number, and volume in the accumulation mode where most of the particle mass is found. At 75% load, number decreased by 38%, DGN decreased from 80 to 62 nm, and volume decreased by 82%. Part of this decrease is likely associated with the fact that the particles were more easily oxidized. Arrhenius parameters for the biodiesel fuel showed a 2-3times greater frequency factor and approximately 6 times higher oxidation rate compared to regular diesel fuel in the range of 700-825 degrees C. The faster oxidation kinetics should facilitate regeneration when used with a DPF.     

Diesel particle filter and fuel effects on heavy-duty diesel engine emissions

The impacts of biodiesel and a continuously regenerated (catalyzed) diesel particle filter (DPF) on the emissions of volatile unburned hydrocarbons, carbonyls, and particle associated polycyclic aromatic hydrocarbons (PAH) and nitro-PAH, were investigated. Experiments were conducted on a 5.9 L Cummins ISB, heavy-duty diesel engine using certification ultra-low-sulfur diesel (ULSD, S ≤ 15 ppm), soy biodiesel (B100), and a 20% blend thereof (B20). Against the ULSD baseline, B20 and B100 reduced engine-out emissions of measured unburned volatile hydrocarbons and PM associated PAH and nitro-PAH by significant percentages (40% or more for B20 and higher percentage for B100). However, emissions of benzene were unaffected by the presence of biodiesel and emissions of naphthalene actually increased for B100. This suggests that the unsaturated FAME in soy-biodiesel can react to form aromatic rings in the diesel combustion environment. Methyl acrylate and methyl 3-butanoate were observed as significant species in the exhaust for B20 and B100 and may serve as markers of the presence of biodiesel in the fuel. The DPF was highly effective at converting gaseous hydrocarbons and PM associated PAH and total nitro-PAH. However, conversion of 1-nitropyrene by the DPF was less than 50% for all fuels. Blending of biodiesel caused a slight reduction in engine-out emissions of acrolein, but otherwise had little effect on carbonyl emissions. The DPF was highly effective for conversion of carbonyls, with the exception of formaldehyde. Formaldehyde emissions were increased by the DPF for ULSD and B20.     

餐厨废弃油脂生物柴油对船舶柴油机性能、排放特性以及燃烧特性的影响北大核心CSCD

为探讨生物柴油应用于船舶柴油机的可行性,将餐厨废弃油脂生物柴油与柴油混合,在船舶柴油机上进行试验,测试其对船舶柴油机性能、排放特性和燃烧特性的影响。结果表明:生物柴油混合物的高黏度以及低热值会降低有效热效率,并导致燃油消耗率略有升高;由于生物柴油的高含氧量促进完全燃烧,相比于柴油,燃烧生物柴油混合物后,一氧化碳排放量最高下降17%,二氧化碳排放量最高下降5.1%,二氧化硫排放量最高下降41%,碳烟排放量最高下降36%;生物柴油过快的燃烧速率提高了气缸内的燃烧温度,以及高含氧量促进了氮氧化物的排放;生物柴油混合物燃烧时的缸内压力与柴油非常接近。餐厨废弃油脂生物柴油对船舶柴油机的性能、燃烧特性和排放特性均具有较好的表现,可以作为柴油的替代燃料用于船舶柴油机。     

生物柴油掺氨对均质压燃发动机燃烧及排放性能的影响

为提升燃料的综合燃烧品质和性能,进一步降低有害物质排放和缓解温室效应,以燃烧动力学和化学反应机制作为理论基础,采用Chemkin软件将生物柴油替代物和氨气充分融合,模拟并计算氨气掺混比例分别为0、5%、10%、15%、20%的5组燃料在均质压燃发动机模式下燃烧和排放指标的数值,对比分析得到不同掺混比例对发动机燃烧和排放的影响和变化规律。结果表明：随着氨气掺混比例增加,燃料的点火滞燃期有所缩短,缸内燃烧最高温度升高,排温降低;排放方面,NO_x的排放升高,CO₂、CO和总碳氢化合物(THC)的排放均明显降低;生物柴油掺混氨气的最佳比例为20%,此时发动机功率下降12百分点,NO的单位功率排放升高了0.003 kW^-1,而CO₂和THC的单位功率排放分别降低了0.01 kW^-1和0.001 3 kW^-1。综上,生物柴油掺混氨气后改善了燃烧性能,降低了排放量,具有良好的应用前景。