大豆生物柴油混合燃料性能试验研究

通过在R4105T柴油机上进行对比试验,分析了0#柴油/生物柴油、乙醇/生物柴油混合燃料以不同比例掺混时对柴油机动力性、经济性及碳烟排放特性的影响.研究结果表明:柴油机使用0#柴油/生物柴油混合燃料时动力性、碳烟排放量均有所下降,油耗率稍有上升;使用乙醇/生物柴油混合燃料时,碳烟排放量低于生物柴油,动力性、经济性随乙醇含量的不同而呈现不同的变化趋势.     

PODE3/异辛烷二元燃料实验与简化动力学模型研究

聚甲氧基二甲醚(PODE)具有高十六烷值、高含氧量和互溶性好等燃料特性,目前PODE通常与传统燃料混合使用,具有显著改善内燃机热效率和有害物排放的潜力.本文首先基于射流搅拌反应器开展典型汽油替代物异辛烷与高活性代用燃料PODE₃混合燃料的低温氧化实验,然后通过简化PODE₃详细机理并耦合异辛烷/正庚烷机理构建了包含108个组分和434个反应的PRF-PODE₃简化机理.利用该机理模型对PODE₃/异辛烷燃料进行了滞燃期、层流预混火焰和射流搅拌反应器的实验验证并获得了良好的预测结果.PODE₃/异辛烷低温氧化实验及模拟结果表明,掺混PODE₃后,会在低温反应阶段产生大量的OH、HO₂、CH₃等活性基,从而促进异辛烷的低温反应,且随着掺混比例的提高,异辛烷低温反应明显增强.异辛烷中添加PODE₃对于CH₄、C₂H₆等中间产物影响较小,但会显著降低C₂H₄和C₃H₆等中间产物的浓度,具备显著改善PAH和碳烟生成的潜力.     

联合CO2捕集的生物质化学链气化制备合成气系统分析

本文提出以Fe₂O₃为载氧体、以CaO捕集CO₂的生物质化学链气化系统,利用Aspen Plus软件对该系统进行了模拟,以合成气组成（干基）、合成气氢碳比、含碳产物的碳摩尔分布、冷气效率及收率等为系统性能评价指标,重点分析了燃料反应器温度（T_FR）、载氧体Fe₂O₃与生物质碳摩尔比（Fe₂O₃/C）、水蒸气与生物质碳摩尔比（Steam/C）、CaO与生物质碳摩尔比（CaO/C）等系统参数对固体生物质化学链气化系统的影响。结果表明,在T_FR = 825℃、Fe₂O₃/C = 0.5、Steam/C = 0.71和CaO/C = 0.26条件下,合成气制备系统性能较优,合成气中H₂和CO₂含量分别为55.2%和15.4%,氢碳比为1.93,冷气效率为78.2%,被CaCO₃捕集的生物质碳为18.2%,收率（湿气基）为1.95 Nm³/kg_biomass,其中合成气中H₂和CO收率为1.24 Nm³/kg_biomass。     

烷烃燃料微小平板催化燃烧的火焰特性

对微平板燃烧器内4种烷类燃料（C₁ ~ C₄）进行铂催化燃烧实验,获得其点火过程和静态火焰的特征,并进行对比分析。当量比相同时,点火过程火焰传播速度大小顺序为甲烷 > 乙烷 > 丁烷 > 丙烷。随着当量比增大,火焰传播速度加快,稳态火焰根部位置向气流上游移动。观察可见光、430 nm（OH*光谱）、516 nm（C₂*光谱）成像火焰发现,当量比越大,火焰亮度越大,OH*和C₂*浓度越高。当量比相同时,乙烷的OH*、CH*和C₂*浓度最高,而甲烷和丙烷的则较低。     

碱改性HZSM-5热解生物质模型化合物影响研究

实验采用Py-GC/MS在500 ℃下对NaOH、Na₂CO₃和有机碱（CTAB/TPAOH）改性HZSM-5催化热解生物质模型化合物的产物分布影响机制进行探究。结果表明,利用0.1 mol/L NaOH/Na₂CO₃改性HZSM-5使热解油中小分子酮、酚和酯类物质的收率有所提高,有利于碳链长度≥5产物（C_≥5）的生成;0.2 mol/L NaOH/Na₂CO₃改性HZSM-5催化剂有助于脱羰和脱羟基反应的进行,促使环状化合物开裂转化为链状化合物。TPAOH的加入使NaOH改性HZSM-5催化热解产物中酮类产物收率降至18.56%、醛类产物收率增至3.01%,并促使C_≥9产物向C_≤4转化,链状产物增加;经CTAB改性后C_≥9产物向C_5-8转化,环状产物增加。     

O3质量浓度对低温等离子体氧化柴油机PM的影响

为高效利用臭氧（O₃）氧化去除柴油机颗粒物（PM）,探究O₃自身热分解规律,分析不同O₃质量浓度的低温等离子体（NTP）气体对柴油机颗粒物的去除量和可溶性有机物（SOF）组分的影响．基于O₃热分解反应方程和Arrhenius公式推导出O₃热分解反应动力学计算公式,分析了反应温度对O₃变化的影响．搭建了低温等离子体氧化去除颗粒物的试验系统,对低温等离子体作用前、后的颗粒物去除量以及SOF进行分析．结果表明：O₃热分解的反应活化能为2.81×10⁴J/mol、温度为80～100℃时O₃具有较低的分解率和较优的反应速率．O₃质量浓度的提高对NTP氧化去除柴油机颗粒物的效果非常显著．低温等离子体对PM中SOF的作用主要体现在碳链的缩减,并在碳链中键入O．随着O₃质量浓度的增加,SOF组分中含氧基团的组分比例提高,并且组分中的含氧基团数量增多．     

生物柴油

<正>生物柴油(Biodiesel)是指以油料作物如大豆、油菜、棉、棕榈等野生油料植物和工程微藻等水生植物油脂以及动物油脂、餐饮垃圾油等为原料油通过酯交换工艺制成的可替代石化柴油的可再生柴油燃料。生物柴油是生物质能的一种,它是生物质利用热裂解等技术得到的一种长链脂肪酸的单烷基酯。生物柴油是含氧量极高的复杂有机成分的混合物,这些     

NiMoB/γ-Al-2O3催化生物油加氢提质

试验以NiMoB/γ-Al2O3为催化剂,在一定温度条件下,考察了对玉米秸秆快速热裂解油(生物油)的加氢提质效果。结果表明,在80℃下,生物油中部分代表性不饱和醛酮化合物(如糠醛、苯甲醛、环己酮、乙醛、乙酰丙酮等)可以在甲醇溶液中被高效地加氢转化为相应的醇。由于生物油中含水量高和各类不饱和化合物含量很低的原因,直接对生物油加氢时,只能部分地将其转化为饱和化合物。研究发现,生物油经超临界萃取处理获得的轻组分,其加氢能力明显增强,羰基化合物(C=O)和碳碳双键化合物(C=C)的转化率分别可达87%和70%。加氢过程中会伴有酯化反应,加氢处理生物油的酸度明显降低,热稳定性提高。     

大豆生物柴油混合燃料性能试验研究

通过在R4105T柴油机上进行对比试验,分析了0#柴油／生物柴油、乙醇／生物柴油混合燃料以不同比例掺混时对柴油机动力性、经济性及碳烟排放特性的影响。研究结果表明：柴油机使用0#柴油／生物柴油混合燃料时动力性、碳烟排放量均有所下降,油耗率稍有上升;使用乙醇／生物柴油混合燃料时,碳烟排放量低于生物柴油,动力性、经济性随乙醇含量的不同而呈现不同的变化趋势。     

F-T/PODE掺混燃料对混合动力柴油机起动特性的影响

基于单轴并联式混合动力试验平台,以0号柴油、煤基费托合成柴油（F-T柴油）和聚甲氧基二甲醚（PODE）为基础燃油,研究0号柴油、F-T柴油及F90P10（PODE体积分数为10%）和F80P20（PODE体积分数为20%）4种燃油在不同的起动瞬态变化条件下的燃烧和排放特性,分析F-T柴油/PODE掺混燃料对混合动力柴油机起动特性的影响．结果表明：与0号柴油相比,燃用F-T柴油时起动燃烧首循环的缸内压力、放热率和压力升高率峰值都有所降低,燃烧持续期增大;冷起动工况下,CO、NO_x排放峰值在24 V原机起动时分别降低42.3%和32.4%,800 r/min拖动起动时分别降低50.9%和55.0%,而碳烟峰值略有升高;热起动工况下,CO、NO_x和碳烟排放峰值在24 V原机起动时分别降低66.4%、64.5%和34.4%,800 r/min拖动起动时分别降低57.0%、48.6%和24.8%．与F-T柴油相比,随着PODE体积分数的增大,起动中CO和NO_x排放峰值略微增大,但碳烟排放大幅降低,弥补F-T柴油在冷起动时碳烟排放升...     

Inhibition of NO emission by adding antioxidant mixture in Jatropha biodiesel on the performance and emission characteristics of a C.I. engine

In this paper, the effect of adding an antioxidant mixture in Jatropha biodiesel as fuel, in a single cylinder, direct injection compression ignition engine was experimentally investigated and the level of pollutants in the exhaust and performance characteristics of the engine were analyzed. Nine test fuels were prepared with three antioxidants, namely, Succinimide (C₄H₅NO₂), N,N-dimethyl-p-phenylenediamine-dihydrochloride (C₈H₁₄Cl₂N₂), and N-phenyl-p-phenylenediamine (C₆H₅NHC₆H₄NH₂) added to neat biodiesel at 500 parts per million (ppm), 1000 ppm and 2000 ppm and the observed experimental results were compared with those of neat biodiesel and neat diesel as base fuels. The comparison showed that NO emission was reduced drastically for the test fuels with the antioxidant addition of 2000 ppm. The maximum reduction of 10% of NO emission was observed for the antioxidant mixture in neat biodiesel, with a slight increase in unburned HC, CO and smoke opacity. In addition, the obtained experimental results reveal that the addition of two antioxidants as mixture in neat biodiesel caused improved NO emission reduction for all test fuels.     

Quality of gas produced from wheat straw in a dual-distributor type fluidized bed gasifier

A 400 kW, dual distributor type fluidized bed gasifier was used to investigate the production rate and composition of the gas produced from wheat straw at various equivalence ratios (0.17, 0.20, 0.25, 0.35) and fluidization velocities (0.28, 0.33 and 0.37 m s⁻). The results showed that the equivalence ratio was the major parameter affecting the gas composition. The equivalence ratio of 0.25 appeared to be the optimum with respect to the quality of the gas. The mole fractions of the combustible components reached their maximum values at this equivalence ratio. A typical gas composition at the equivalence ratio of 0.25 was 7% H₂, 7% hydrocarbons (CH₄, C₂H₂, C₂/H₄ and C₂H₆), 14% C0₂, 22% CO and 50% N₂. The higher heating value of the produced gas (6.3–7.3 MJ Nm⁻³) obtained at this equivalence ratio appeared to be higher than most values reported in the literature for several types of biomass fuels.     

Estimation of the sauter mean diameter for biodiesels by the mixture topological index

A pure component topological index was integrated with the modified Grunberg–Nissan or the modified Dalton-type mass?average equation to calculate the mean topological index χ_m,1 or χ_m,2 of five biodiesel fuels (peanut, canola, coconut, and palm, soybean oil). Then, the χ_m,1 or χ_m,2 was respectively related with the SMD values of biodiesel fuels (taken from the literature, at 313 K), and two regression equations were obtained. The regression equation derived from χ_m,1 has a higher predictive accuracy than the regression equation derived from χ_m,2, and the deviations of these two regression equations were within 1.73% and 1.87%, respectively. Furthermore, a regression equation derived from the correlation of χ_m,1 and SMD was used to calculate the SMD values of biodiesel fuels (at 353 K), and the deviations were within 0.78%. Three types of hypothetical biodiesel fuels were investigated to know the effect of the molecular structure (carbon number and unsaturated bond) on the SMD. A suitable material for the preparation of a biodiesel having the comparable atomization with the diesel no.1 or no.2 will be composed of such components (low carbon number and more unsaturated bonds).     

A prospective study of bioenergy use in Mexico

Bioenergy is one of the renewable energy sources that can readily replace fossil fuels, while helping to reduce greenhouse gas emissions and promoting sustainable rural development. This paper analyses the feasibility of future scenarios based on moderate and high use of biofuels in the transportation and electricity generation sectors with the aim of determining their possible impact on the Mexican energy system. Similarly, it evaluates the efficient use of biofuels in the residential sector, particularly in the rural sub-sector. In this context, three scenarios are built within a time frame that goes from 2005 to 2030. In the base scenario, fossil fuels are assumed as the dominant source of energy, whereas in the two alternative scenarios moderate and high biofuel penetration diffusion curves are constructed and discussed on the basis of their technical and economical feasibility. Simulation results indicate that the use of ethanol, biodiesel and electricity obtained from primary biomass may account for 16.17% of the total energy consumed in the high scenario for all selected sectors. CO₂ emissions reduction—including the emissions saved from the reduction in the non-sustainable use of fuelwood in the rural residential sector—is equivalent to 87.44 million tons of CO₂ and would account for 17.84% of the CO₂ emitted by electricity supply and transportation sectors when the base case and the high scenario are compared by 2030.     

Low-temperature catalytic partial oxidation of hydrocarbons (C1–C10) for hydrogen production

The catalytic partial oxidation of hydrocarbons to provide hydrogen for fuel cells, mobile or stationary, requires high temperatures (900°C), multireactors and incurs the highest incremental costs for the gasoline fuel processor. New experimental data between 500°C and 600°C, supported by equilibrium calculations, show that hydrogen with low carbon monoxide concentrations can be produced from liquid and gaseous hydrocarbons, thus simplifying the reactor chain. Low sulphur refinery feeds (C₄–C₆, C₄–C₁₀), simulated natural gas (C₁–C₃) and single compounds are used and safety procedures discussed. Results from laboratory reactors with 1 wt% rhodium on mixed oxide catalysts show that hydrogen rates of 43,000 lH₂/h/l reactor (power density 129 kWth/l reactor) are produced with RON=95 feeds. However, the cost and availability of rhodium limit the catalyst rhodium content to 0.1 wt% when 31,100 lH₂/h/l reactor were measured. Optimisation and reactor scale-up for heat management is in progress.     

我国生物质能源现代化应用前景展望(三)——生物质能源转化技术经济评估

秸秆、动植物油脂、微藻等生物质原料可以生产液体运输燃料,生物燃料的化学成分包括醇、酯、烃三类。燃料乙醇主要替代汽油,受到各国重视,其中纤维素乙醇技术发展较快。脂肪酸甲酯是第一代生物柴油的主要成分,价格主要受油脂原料价格的影响,由于和柴油相容性差,低温流动性不好,将逐渐被加氢生产的第二代生物柴油取代。相比醇、酯等含氧燃料,烃类生物燃料在使用性能上有很多优势。有多条技术路线可以生产烃类燃料,其中油脂加氢制喷气燃料已接近商业应用,热解油加氢可将木质生物质原料中的"木质素"组分转化为生物油,大型快速热解工厂可以和热电联产装置组成联合系统,从而提高工厂综合热效率,降低生物燃料生产成本。因此,快速热解生产汽柴油将成为主要的生物燃料生产路线。生物质与煤共气化技术通过提高气化温度,不仅可以提高生物质气化效率,减少焦油的生成,还可以解决生物质供给的季节性问题,为生物质的高效利用提供了一条新的技术途径。微藻高压液化生产柴油是最具发展潜力的第三代生物燃料技术,我国需要加强微藻养殖及加工技术攻关。     

Variations in the chemical composition and morphology of soot induced by the unsaturation degree of biodiesel and a biodiesel blend

This work is about the influence of the molecular structure of the fatty acid esters present in two neat biodiesel fuels and their blend (50% by volume) on particulate matter emission. Experiments were performed in a four-cylinder direct injection automotive diesel engine under carefully controlled operating conditions, so that the difference in performance and emissions were affected only by biodiesel fuels composition and properties. The results indicated that the composition and degree of unsaturation of the methyl ester present in biodiesel plays an important role in the chemical composition of particulate matter (PM) emitted. It was observed that linseed biodiesel (BL100) produces more PM and hydrocarbons (HC) than Palm biodiesel (BP100) as a consequence of more unsaturated compounds in its composition, which favor the soot precursor’s formation in the combustion zone. Thermogravimetric analysis (TGA) showed that the amount of volatile material in the soot from biodiesel fuels was slightly lower than that of diesel fuel, but not significant differences were observed among biodiesels. Similarly, the chemical characteristics of the hydrocarbons of volatile material present in the particulate matter (referred in the literature as SOF-soluble organic fraction), showed an increase in the aliphatic component as the unsaturation degree of the fatty acid methyl ester increased. Additionally, it is concluded that there are not significant nano-structural differences in the soot obtained from pure biodiesel fuels, even if they have very different degrees of unsaturation.     

Vaporization modeling of petroleum-biofuel drops using a hybrid multi-component approach

Numerical modeling of the vaporization characteristics of multi-component fuel mixtures is performed in this study. The fuel mixtures studied include those of binary components, biodiesel, diesel-biodiesel, and gasoline-ethanol. The use of biofuels has become increasingly important for reasons of environmental sustainability. Biofuels are often blended with petroleum fuels, and the detailed understanding of the vaporization process is essential to designing a clean and efficient combustion system. In this study, a hybrid vaporization model is developed that uses continuous thermodynamics to describe petroleum fuels and discrete components to represent biofuels. The model is validated using the experimental data of n-heptane, n-heptane-n-decane mixture, and biodiesel. Since biodiesel properties are not universal due to the variation in feedstock, methods for predicting biodiesel properties based on the five dominant fatty acid components are introduced. Good levels of agreement in the predicted and measured drop size histories are obtained. Furthermore, in modeling the diesel-biodiesel drop, results show that the drop lifetime increases with the biodiesel concentration in the blend. During vaporization, only the lighter components of diesel fuel vaporize at the beginning. Biodiesel components do not vaporize until some time during the vaporization process. On the other hand, results of gasoline-ethanol drops indicate that both fuels start to vaporize once the process begins. At the beginning, the lighter components of gasoline have a slightly higher vaporization rate than ethanol. After a certain time, ethanol vaporizes faster than the remaining gasoline components. At the end, the drop reduces to a regular gasoline drop with heavier components. Overall, the drop lifetime increases as the concentration of ethanol increases in the drop due to the higher latent heat.     

Effect of biodiesel fuels on diesel engine emissions

The call for the use of biofuels which is being made by most governments following international energy policies is presently finding some resistance from car and components manufacturing companies, private users and local administrations. This opposition makes it more difficult to reach the targets of increased shares of use of biofuels in internal combustion engines. One of the reasons for this resistance is a certain lack of knowledge about the effect of biofuels on engine emissions. This paper collects and analyzes the body of work written mainly in scientific journals about diesel engine emissions when using biodiesel fuels as opposed to conventional diesel fuels. Since the basis for comparison is to maintain engine performance, the first section is dedicated to the effect of biodiesel fuel on engine power, fuel consumption and thermal efficiency. The highest consensus lies in an increase in fuel consumption in approximate proportion to the loss of heating value. In the subsequent sections, the engine emissions from biodiesel and diesel fuels are compared, paying special attention to the most concerning emissions: nitric oxides and particulate matter, the latter not only in mass and composition but also in size distributions. In this case the highest consensus was found in the sharp reduction in particulate emissions.