Critical Evaluation of Rotary Atomizer

Abstract

The flammability characteristics of jet fuel aerosols are critical to the development of fire-safe fuels. In efforts to design and characterize fire-safe fuels, an automated rotary atomizer has been constructed to produce fuel aerosols and measure their mist flammability properties. A particle analyzer has been coupled directly to the atomizer to provide drop size distribution information on the aerosols. The size distribution measurements provide crucial evidence regarding the droplet formation mechanism of the constructed atomizer. This paper focuses on the evaluation of water aerosols as a function of disk speed, flow rate to the atomizer, and liquid surface tension utilizing this instrumental design.     

The Construction of an Improved Automated Atomizer for Evaluating Jet Fuel Flammability

The flammability characteristics of jet fuel aerosols are significant parameters for the development of fire safe fuels. In our laboratory's efforts to evaluate the success of specific chemical additives designed to reduce the ignition of jet fuel aerosols, we have developed a unique, completely automated atomizer for producing aerosols and measuring their mist flammability properties.     

气泡发生结构对二级燃油雾化喷嘴性能影响的实验研究

基于一种气泡气动二级燃油雾化喷嘴,在其第二级雾化气动旋流部分结构参数一定的条件下,对第一级气泡雾化中的气、液预混芯与气泡生成室相配合的结构进行了优化设计,并利用可适性相位多普勒激光测速仪对不同气泡发生结构下的雾化场进行实验测试。结果表明,预混芯的气孔数目、气液面积比以及气泡生成室的长宽比均对喷嘴雾化效果有影响。     

PODE/柴油混合燃料燃烧颗粒的粒径分布及微观结构

以高压共轨柴油机为样机,采用发动机排气粒径谱仪(EEPS)和高分辨率透射电镜(HRTEM),考察了聚甲氧基二甲醚(PODE)/柴油混合燃料燃烧颗粒的粒径分布规律及微观结构特征。所用燃油为纯柴油、PODE体积分数(掺混比)分别为10%、20%和30%的PODE/柴油混合燃料。结果表明,在最大扭矩转速100%负荷时,与柴油相比,混合燃料燃烧颗粒的核模态颗粒数量增加,积聚态颗粒数量降低。随掺混比的提高,排气颗粒的数量浓度分布、质量密度分布、质量累积分布和质量中位径均向小粒径方向偏移。掺混PODE后燃烧颗粒的微观结构主要呈团状分布;与柴油相比,混合燃料颗粒的层面间距和微晶曲率增大,微晶尺寸减小,而颗粒的盒维数增加,团聚程度也有所提高。     

The Instability of Storage of Middle Distillate Fuels: A Review

Abstract

The author reviews the research studies that have been so far carried out and reported in the literature on the stability of middle distillate fuels. The emphasis is mainly given to understand the stability of diesel fuels. It has been divided into five principle sections: (a) Introduction, (b) Methods for Determination of Fuel Stability, (c) Mechanism of Degradation, (d) Composition of Total Gum, and (e) Current Status of Methods to Improve Fuel Stability. The introduction provides information of in-stabilization of distillate fuel that depends on the various blending streams of middle distillates in the introduction part. In the second section the author elaborate the methods so far used to determine the instability of middle distillate fuels. The third section serves the elaborated mechanism of degradation, the role of chemical composition of distillate fuels, and the responsible components in distillate fuels that impart in degradation of distillate fuels. The fourth section comprises the composition of material formed during degradation and the fifth section of reveals the current status of methods used to improve the stability. In combination, these five sections would provide a ready reference source of data available in the literature on diesel fuel stability.     

用透射电镜考察柴油中蜡晶的形态

测定了兰州石化0#柴油、大庆石化0#柴油和格尔木炼油厂0#柴油中正构烷烃的碳数分布, 也测定了它们添加降凝剂前后的冷滤点(CFPP), 并利用透射电镜观察了添加降凝剂(PPD)前后样品在低温下的蜡晶微观形态。结果表明,柴油未加降凝剂时,蜡晶在低温下的尺寸在200nm以上;添加降凝剂后,若能将柴油的蜡晶颗粒分散为100nm以下,则具有较好的降凝效果。从蜡晶的微观尺寸解释了柴油降凝剂的作用机理。     

THE INTERACTIONS OF THIOLS WITH OLEFINS AND THEIR EFFECTS ON AUTOXIDATION DURING JFTOT TESTING

Previous research has shown that low concentrations of thiols will act as radical traps to inhibit autoxidation. When added to a fuel, thiols accelerated the rate of oxygen reaction without a commensurate increase in peroxidation. Evidence for the oxidative addition of thiols to olefins has been found to occur by studying the addition of thiophenol to indene in a model fuel during stressing in the JFTOT apparatus. Two different thiol-indene adducts were found in the effluent, with the product distribution being temperature dependent. This process could account, in part, for the differences in thiol influences on autoxidation observed in model systems and in fuels.     

IGNITION DELAY CHARACTERISTICS OF SOME TURKISH VEGETABLE OIL-DIESEL FUEL BLENDS

Vegetable oils have chances to be used in Diesel engines as alternative fuels contributing to the solution of some agricultural, environmental and economical problems. Direct use of them has some technical problem yet but as blended fuels with diesel fuel or esters they have places on the application area. In this paper the effect of the compression ratio on ignition delay is investigated in an ASTM-CER engine working with four different types of vegetable oil of Turkish origin (sunflower, corn, soybean, and olive oil) blended with grade No.2-D diesel fuel at a ratio of 20/80 (v/v) and the results are compared with baseline diesel fuel. Longer ignition delay periods have generally been obtained for blend fuels ranking from olive oil to sunflower oil as compared to diesel fuel.     

AUSTRALIAN BROWN COAL/OIL MIXTURES AS A FUEL FOR DIESEL ENGINES; ENGINE PERFORMANCE AND ECONOMIC VIABILITY

CSIRO Division of Energy Technology has used mixtures of finely ground, chemically beneficiated, Australian brown coal (up to 30% by weight, maximum particle size less than 13 microns) and automotive diesel oil (ADO) to fuel an essentially unmodified single cylinder diesel engine operating at 800, 1200 and 1500 r/min. Engine performance tests indicate that brown coal can be used as a fuel extender to reduce consumption of the conventional liquid diesel fuel (ADO). Partially burnt coal agglomerates were identified in the engine exhaust and there were indications of late burning at the higher engine speeds and coal concentrations. Engine brake thermal efficiency ratio is identified as an important parameter when evaluating the thermal performance and economic viability of new fuels for internal combustion engines. A simple economic model based on 'payback period' is developed and used to assess the viability of converting an existing diesel engine powered plant to operate on the coal/oil mixture fuels (COM). The simple economic analysis technique can also be applied to other fuel formulations and fuel extenders. Conversion of large, slow speed stationary diesel engines to operate on brown COM fuels is shown to be uneconomical, given a projected brown coal cost of 215 $A/t (including processing).     

IGNITION DELAY CHARACTERISTICS OF SOME TURKISH VEGETABLE OIL-DIESEL FUEL BLENDS

ABSTRACT

Vegetable oils have chances to be used in Diesel engines as alternative fuels contributing to the solution of some agricultural, environmental and economical problems. Direct use of them has some technical problem yet but as blended fuels with diesel fuel or esters they have places on the application area. In this paper the effect of the compression ratio on ignition delay is investigated in an ASTM-CER engine working with four different types of vegetable oil of Turkish origin (sunflower, corn, soybean, and olive oil) blended with grade No.2-D diesel fuel at a ratio of 20/80 (v/v) and the results are compared with baseline diesel fuel. Longer ignition delay periods have generally been obtained for blend fuels ranking from olive oil to sunflower oil as compared to diesel fuel.     

AUSTRALIAN BROWN COAL/OIL MIXTURES AS A FUEL FOR DIESEL ENGINES; ENGINE PERFORMANCE AND ECONOMIC VIABILITY

ABSTRACT

CSIRO Division of Energy Technology has used mixtures of finely ground, chemically beneficiated, Australian brown coal (up to 30% by weight, maximum particle size less than 13 microns) and automotive diesel oil (ADO) to fuel an essentially unmodified single cylinder diesel engine operating at 800, 1200 and 1500 r/min. Engine performance tests indicate that brown coal can be used as a fuel extender to reduce consumption of the conventional liquid diesel fuel (ADO). Partially burnt coal agglomerates were identified in the engine exhaust and there were indications of late burning at the higher engine speeds and coal concentrations. Engine brake thermal efficiency ratio is identified as an important parameter when evaluating the thermal performance and economic viability of new fuels for internal combustion engines. A simple economic model based on ‘payback period’ is developed and used to assess the viability of converting an existing diesel engine powered plant to operate on the coal/oil mixture fuels (COM). The simple economic analysis technique can also be applied to other fuel formulations and fuel extenders. Conversion of large, slow speed stationary diesel engines to operate on brown COM fuels is shown to be uneconomical, given a projected brown coal cost of 215 $A/t (including processing).     

相平衡方法研究柴油中石蜡结晶行为

 应用冷滤点测定仪分离在冷滤点温度下的模拟柴油、加剂模拟柴油、基础柴油及加剂柴油的液相和固相，用气相色谱法测定液、固两相中正构烷烃的组成，并通过分配因子Z计算得到在冷滤点温度下石蜡结晶量、石蜡的正构烷烃含量。实验结果表明，用该分离方法以及计算方法来研究柴油在冷滤点温度下液-固平衡态的结晶行为是可行的。     

THE INTERACTIONS OF THIOLS WITH OLEFINS AND THEIR EFFECTS ON AUTOXIDATION DURING JFTOT TESTING

ABSTRACT

Previous research has shown that low concentrations of thiols will act as radical traps to inhibit autoxidation. When added to a fuel, thiols accelerated the rate of oxygen reaction without a commensurate increase in peroxidation. Evidence for the oxidative addition of thiols to olefins has been found to occur by studying the addition of thiophenol to indene in a model fuel during stressing in the JFTOT apparatus. Two different thiol-indene adducts were found in the effluent, with the product distribution being temperature dependent. This process could account, in part, for the differences in thiol influences on autoxidation observed in model systems and in fuels.     

气相色谱-质谱联用技术测定喷气燃料烃类碳数分布

利用基于电子轰击电离源(EI)的气相色谱-质谱(GC-MS)联用技术,建立测定喷气燃料中不同类型烃类碳数分布的分析方法。将喷气燃料预分为饱和烃与芳烃组分后,分别采集其总离子流色谱图(TIC)。在利用TIC的平均质谱图计算烃类组成的基础上,从TIC谱图中分别提取不同类型、不同碳数化合物的分子离子峰。对同类型、不同碳数化合物的分子离子峰面积通过不同碳数响应因子进行校正,并将校正后的面积进行归一化计算,得到该类型化合物的碳数分布信息。该方法与气相色谱 场电离飞行时间质谱(GC-FI TOF MS)、气相色谱 氢火焰离子化检测器(GC-FID)测定烃类碳数分布比较吻合,3种方法得到的碳数分布相对偏差均小于5%,且重复性良好。利用建立的方法考察了大庆直馏、乌石化加氢裂化、直接液化煤基、生物基4种不同类型喷气燃料的分子组成,结果表明,不同类型喷气燃料主要烃类组成存在差别。     

THE IMPACT OF RED DYE ON THE STABILITY OF MARINE DIESEL FUELS

The use of red dye formulations to identify high sulfur diesel fuels were mandated before their effects on fuel stability had been thoroughly investigated. The effects of the red dye on stability were studied in a group of ten low- and high-sulfur diesel fuels. The red dye was not found to significantly degrade storage stability and thermal oxidation stability of these fuels, beyond normal variations. There were some effects noticed on blending compatibility, but, in general, these were within the range of effects due to fuel composition.     

IGNITION DELAY AND SOOT EMISSION CHARACTERISTICS OF METHANOL-DIESEL FUEL BLENDS

Alcohols, as alternative fuels, may contribute to the solution of environmental and economical problems to a certain extend. But, they seem to have little chances to be directly used in Diesel engines because of their low cetane number. However, as blended fuels with diesel fuel they have places on the application area. In this study, the effect of the compression ratio on ignition delay and soot emission for methanol-diesel fuel blends with various blending ratios is investigated on an ASTM-CFR engine and the results are compared with baseline diesel fuel. Longer ignition delays and less soot emissions have been obtained for blend fuels as compared to diesel fuel.     

正丁醇/汽油多组分表征燃料化学反应动力学机理模型构建及优化

为进一步探究正丁醇/汽油的燃烧本质、丰富其燃烧理论,基于多种骨架简化方法,以正丁醇代表丁醇、甲苯参考燃料(TRF)表征汽油,构建了包含110种组分、445步反应的正丁醇/汽油多组分表征燃料化学反应动力学机理模型。结合滞燃期敏感性分析法,对该机理模型进行了优化,并在宽广工况下对优化后的简化机理模型进行了验证。结果表明,该机理模型可以准确捕捉混合燃料的滞燃期和层流火焰速度,再现燃料在射流搅拌反应器中的氧化反应过程,也可以为后续耦合计算流体力学进行数值模拟,提供合适的简化机理模型。     

MECHANISMS OF SYNFUEL DEGRADATION. 3. INTERACTIVE EFFECTS IN NITROGEN COMPOUND INDUCED STORAGE INSTABILITY IN SHALE DERIVED DIESEL FUEL

Deterioration in fuel quality upon storage has been a continuing problem in the utilization of middle distillate fuels. For diesel fuels. Instability is usually defined by the formation of insoluble sediments and gums and by the accumulation of hydroperoxides. Gravimetric accelerated storage stability tests conducted with model compounds as dopants in otherwise stable distillate fuels have demonstrated that oxidative condensation reactions of polar heterocylces are deleterious to stability. In particular, nitrogen containing aromatics (pyrroles, pyridinea, indoles, etc.) appear to be very harmful. Correlation of model dopant studies with results obtained with actual unstable fuels has indicated that autoxidation processes are usually not isolated reactions but are sensitive to the presence of other fuel constituents. In an effort to learn more about potential interactive effects, we have examined the autoxidation of two model compounds, 2, 5-dimethylpyrrole and 3-methylindole, in a shale diesel fuel in the presence of a second model dopant (a hydroperoxide, organic acid or base). The results presented support the notion that such interactive effects may be of critical importance in defining the stability of actual middle distillate fuels.     

燃气组分变化对重整燃烧器燃烧过程及炭粒生成的影响

采用数值模拟方法对连续重整加热炉燃烧器的流动和燃烧过程进行研究,分别考察氢气、甲烷、乙烷、丙烷和丁烷五种不同的气体燃料对燃烧过程的影响,重点研究在燃烧不同气体燃料时的燃烧状况和火焰形状的变化情况及形成原因,同时考察燃气组分变化对炭粒生成的影响。结果表明,较轻的燃料燃烧迅速,具有较短的刚直火焰,辐射段出口烟气温度较低,燃烧充分,炭粒生成较少;较重的燃料与空气混合慢,火焰较长,辐射段出口烟气温度较高,未完全燃烧的燃料在很大区域存在,炭粒生成较多,并可能形成结焦。     

Soybean Biodiesel: Instability Reactions

It has been suggested that renewable energy sources be considered as replacements for middle distillate ground transportation and marine fuels. It is vital for the operational considerations of these fuels to investigate the many positives and negatives of incorporating these renewable energy sources in such systems. In proposing such a replacement, considerations must be given to the many problems that could arise including fuel storage stability, fuel solubility, oxidative stability, and seawater stability. Contrary to air environments, water environments have a pH factor that has to be considered. United States Navy shipboard fuel tanks compensate for diminishing fuel by the addition of seawater to the fuel tank. It was found that this would lead to fuel instability problems such as filter stoppage and other serious engine damage. Studies were performed to determine what in the soybean-derived biodiesels led to the observed fuel degradation.