喷雾点火条件对柴油爆燃特性的影响

在立式激波管中,通过强点火方式,在常温常压下实现柴油云雾的爆燃,利用升降法测定柴油云雾燃爆的最小点火能,研究了喷雾压力、雾化时间及点火能量对柴油云雾燃爆性能的影响。结果表明柴油云雾在常温常压下可以直接达到爆燃状态,喷雾压力、雾化时间及点火能量对柴油云雾的爆燃压力和爆燃速度有显著影响,存在最佳喷雾压力及雾化时间。     

含氧柴油的性能研究

依据国家石油和石油产品标准试验方法研究了二乙二醇二甲醚、烷基醚、乙酸-2-甲氧基乙酯三种含氧燃料对柴油(密度、粘度、净热值)理化性质的影响规律,筛选出烷基醚最适合作为柴油调和组分使用.在20 L液体燃料爆炸球中,通过弱点火方式,分别在常压和负压条件下实现含氧柴油和空白柴油云雾的燃爆.通过对比燃爆压力和压力上升速率,评价了烷基醚对柴油燃爆的影响规律.结果表明:在常压条件下,烷基醚在柴油中的最佳添加比例为15％(体积比);在负压燃烧条件下,烷基醚能有效地改善柴油的燃烧性能.     

注空气驱油工艺燃爆实验研究

注空气驱油过程中空气会与原油中的挥发气体混合,遇明火容易发生爆炸,造成关井或安全事故。针对这一问题,分析计算了常温常压下的爆炸极限及安全氧含量,用反应釜装置模拟高温高压条件下可燃气体的燃爆特性。结果表明:温度、压力的升高对可燃气体爆炸下限不敏感,但是对爆炸上限很敏感,随着温度、压力的升高,爆炸极限(体积分数)的范围变宽,由常温常压下的4.76%~14.72%增大到1.6%~36.1%。同时对安全氧含量进行了实验测定,并针对不同压力下的可燃物爆炸极限与安全氧含量数值进行了关于温度的二次线性函数拟合,可用于相近温度、压力下的燃爆特性预测。     

新型乳化柴油喷雾特性的试验研究

通过定容弹模拟乳化柴油喷雾形成的全过程,采用高速摄影记录了不同喷油压力、喷油背压以及喷油脉宽下乳化柴油喷雾的形成过程,从喷雾锥角、贯穿距以及锋面速度3个方面对乳化柴油的喷雾特性进行了试验研究,结果表明：乳化柴油的喷雾特性与柴油基本一致,喷油压力对乳化柴油喷雾锥角和贯穿距的影响较大,喷雾背压和喷油脉宽对乳化柴油喷雾贯穿距的影响较大,喷油压力、喷雾背压和喷油脉宽对乳化柴油喷雾锋面速度的影响均较小,较高的喷油压力、较短喷油脉宽有利于乳化柴油的雾化。     

空气钻井井下燃爆控制技术探讨

空气钻井条件下,若钻遇地层含油气流体,且温度和压力满足井下燃爆条件需要,易发生井下燃爆事故。井下燃爆不仅造成钻具、套管被烧毁破坏,还会造成井眼破坏,后续处理困难,造成井眼报废等,其成为了阻碍空气钻井技术的发展瓶颈。文章从燃爆极限、点火方式着手,分析了空气钻井井下燃爆机理,提出了防止井下燃爆控制措施,首先是详细研究地质资料,尽量避开油气层段;在空气钻井作业期间,防止井下燃爆的重点是对井下可燃的流体进行监测,及时发现,及早转换钻井方式;在钻具组合中加入灭火阀也可达到阻燃的目的;在可能出气的层段采用氮气钻井,是避免井下燃爆的有效手段;雾化钻井、泡沫钻井等技术在控制井下燃爆方面也有一定效果。     

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在直径为1 m的球形容器中，采用中心点火方式，对液化石油气进行了大量密闭燃爆和燃爆泄放的实验，得出了液化石油气最大破坏力的浓度范围5%～6%、密闭下燃爆最大压力与初始压力呈线性关系，并基于不同条件下燃爆泄放实验，通过量纲分析将泄放面积、容器内表面积、容器体积、泄放压力及初始压力等关联成燃爆泄放状态准数，建立了燃爆泄放最大超压与泄放准数之间关系式，关系式覆盖的体积范围(0.029～213 m3)，内部初始压力范围（0.1～0.4 MPa），泄放压力与初始压力比（1～2.5）、容器长径比（1～2），在该范围内关系式与实验结果吻合较好。     

苏里格气田致密砂岩储层条件下声波速度与孔隙度实验研究

利用苏里格气田1批岩心实验数据研究了常温常压和高温高压条件下岩样声波速度和孔隙度的变化及相互关系,岩石孔隙度随压力增大以对数形式减小,随温度升高略微减小;岩石声波速度随压力的增大以对数形式增大,随温度的升高线性减小;随埋深的增加,估算压力对声波速度的影响约是温度影响的10～30倍.对不同岩样孔隙度的压力影响系数随孔隙度的增大而减小;声波速度的压力影响系数随孔隙度的增大而增大,因此造成常温常压下孔隙度与声波速度的相关性在储层条件下变差.     

天然气水合物诱导时间影响因素的试验研究

以气体水合物形成过程中的诱导现象为基础,通过对喷雾强化方式制取天然气水合物的诱导时间进行试验研究,考察分析了系统进气方式、温度、压力、水源及喷嘴等因素对诱导时间的影响规律.试验表明,喷雾方式制取天然气水合物时,诱导时间普遍较短,诱导现象不明显;反应釜设定初始温度和压力对诱导时间有一定影响,但不是很明显;水源和雾化喷嘴对诱导时间的影响较大.因此,喷雾强化方式可以大大缩短水合物形成的诱导时间,是一种行之有效的促进水合物形成的技术.     

柴油吸氧安定性能研究(1)--温度和氧压对柴油吸氧安定性能的影响

在温度为 2 90～ 360K、氧气压力为 0 .10～ 0 .2 5MPa、无光照和Cu催化条件下详细考察了温度和氧气压力对大庆直馏柴油和焦化加氢柴油吸氧氧化性能的影响。在给定的试验条件下随温度或氧气压力的升高 ,柴油的吸氧量迅速增加 ;氧气压力或温度越高或时间越长 ,柴油的吸氧量越大 ;在短的吸氧时间下柴油吸氧量的变化幅度较小 ,而在长的时间下柴油吸氧量的变化幅度较大 ;低温对直馏柴油的吸氧量影响较大 ,而高温对焦化加氢柴油的吸氧量影响较显著 ;氧气压力对直馏柴油的吸氧量有较大的影响 ,而对焦化加氢柴油的吸氧量影响较小 ;低温或高氧气压力下焦化加氢柴油的吸氧量小于直馏柴油 ,而在高温或低氧气压力下焦化加氢柴油的吸氧量反而大于直馏柴油。柴油中含有某些不饱和烃 ,特别是共轭二烯烃、环烷、芳香烃类等不安定组分的种类越多及含量越高 ,就越容易发生吸氧氧化反应 ,安定性能或质量下降越明显。     

清净剂对柴油雾化液滴空间分布的影响

采用三维激光粒子动态分析仪(PDA),测量并分析了聚异丁烯酰胺类清净剂质量分数、压力和轴向位置对0#车用柴油雾化液滴空间分布的影响.结果表明:随着清净剂质量分数增大,在喷嘴出口处柴油雾化形成的大液滴所占的比例逐渐降低,小液滴比例逐渐升高,添加清净剂的柴油雾化液滴在小粒径区的速度分布远高于未加剂柴油;随着压力的增加,无论...     

柴油润滑性的影响因素考察

以加氢裂化柴油为空白原料，考察了不同芳烃、硫化物、氮化物和含氧化合物及其混合物对柴油润滑性的影响。结果表明，微量的环烷酸和含氮化合物能有效地改善柴油润滑性，而单环、双环芳烃和硫化物对柴油润滑性的改善效果不明显；不同的化合物混合对柴油润滑性的影响不同。     

天然气/柴油混合燃料发动机的特性研究

单一气体燃料发动机是针对某一种气体燃料的理化特性而专门设计制造的发动机，它可以最大限度地发挥气体燃料的优势，多用于气源供应充分的固定场所（如油气田电站或气源供应稳定的城市公交车辆），但单一气体燃料发动机汽车也存在着续驶里程短、不易压燃等缺点，特别是低负荷工况性能不佳。而与液体燃料组合而形成的混合燃料汽车则消除了这些缺陷，使其具有更强的生命力。为此，根据天然气的燃烧性能，研究了天然气/柴油混合燃料发动机的特性。结果表明：柴油引燃具有多处繁星式点火且点火能量大的特点，因而天然气作为点燃式发动机燃料，爆震和失火倾向大大减小，使其在中高负荷时不但废气排放量降低，而且动力性能较好，而在低负荷时采用纯柴油或者其他措施运行。     

天然气放空管地面爆燃点火装置点火特性研究

针对目前对天然气放空管地面爆燃点火装置点火机理认识的不足,导致其一次点火成功率较低的问题,采用FLACS分析了典型地面爆燃点火装置传火管传火动态过程,探讨了传火管内可燃气体体积分数、可燃气体充装率以及传火管长度对其点火性能的影响。结果表明:传火管内的平均火焰传播速度为155 m/s,为爆燃过程;传火过程中传火管内的最大超压峰值高达2.5×10⁵ Pa,须确保传火管具有足够的承压能力,且应固定牢靠;地面爆燃点火装置应在可燃气体和压缩空气进口管路分别增设流量计量仪表,使传火管内充装体积分数接近于9.5%的可燃气体,并确保充装率在40%以上;传火管的点火性能随其长度的增大而变差,尤其在传火管长度大于35 m后将快速变差。研究成果为天然气放空管地面爆燃点火装置的优化设计、安装固定与点火操作提供了理论支撑。      

汽车节能与排放控制技术进步及其对润滑油的要求

对以汽油机和柴油机为动力的汽车节能及排放控制技术进步进行了综述,这包括传统汽油机的主要技术、缸内直喷式汽油机的应用现状与技术难点、均质混合气压燃技术应用于汽油机的优势与研究进展、柴油机的机内净化技术以及柴油机的排气后处理技术。同时,简要讨论了这些技术进步和变化带来的对润滑油性能的新要求。     

Thermolysis of AP–additive mixtures,III1

Abstract

Thermolysis of ammonium perchlorate (AP) in presence of additives such as CaCO₃ and CaO has been investigated by Ignition delay, DTA, and photomicrography techniques. The ignition delay, ignition temperature, and decomposition temperature and activation energy are found to decrease when CaO was incorporated in AP. However, CaCO₃ affected the ignition of AP at higher temperatures (622-770°K) but very little effect was observed at lower temperatures (<623°K). Thermolysis of AP seems to proceed through condensed phase reactions in presence of CaO and CaCO₃ and role of these additives in the deflagration and decomposition of AP has also been discussed.     

催化柴油中酸性组分对柴油安定性的影响

对用强碱性阴离子交换树脂分离胜利稠油厂的重油催化裂化柴油得到强酸性和弱酸性组分,进行了ＩＲ,ＵＶ色谱、元素分析和羟基值的分析,又将两组分兑入安定性好的绱 进行老化动力学研究,结果表明,这两种组分主要为酚类化合物带有一定的氮化物和硫化物;反应速度与两种酸性组分的存在有很大关系,反应初始速率对酸性组分的浓度呈近似的一级反应,反应有较低的表观活化能。     

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.     

Z12V190B型高速四冲程柴油机工作过程的优化

以柴油机工作过程为基础，建立了优化柴油机工作过程的单目标函数非线性规划的数学模型．应用序贯加权因子法(SWIFT)对Z12V190B型柴油机的工作过程进行了优化计算，提出。通过减小供油提前角，使发火角为最佳。减少活塞在上止点前所做功的方法来达到柴油机节能的效果。     

THE IMPORTANCE OF PYROLYSIS IN DIESEL IGNITION OF RESIDUAL FUEL OILS

Recent attempts to increase yields of distillate fuels from crude oil have resulted in a decline in the ignition quality of residual fuel oils and claims of ignition problems in large marine Diesel engines. This has revived an interest in fundamental studies of the ignition of liquid fuels and in new ways of defining and measuring ignition quality.

As part of an extensive study of the ignition of a range of residual fuels oils and during the development of novel teats of ignition quality it became obvious that thermal cracking of the fuel could play an important part in the pre-ignition chemistry. This paper reports kinetic data from simple experiments performed on the pyrolyses of residual fuel oils. Small samples and high heating rates were used to try to match the conditions inside a Blow-speed Diesel engine. This data has been used to assess the contribution that thermal cracking makes to ignition processes.

Pyrolyses were carried out on a small silica-coated platinum coil in the inlet of a gas chromatograph. Light hydrocarbon pyrolysis products were formed, and the extent and rate of cracking determined at four temperatures.

Assuming that reaction took place on a surface surrounding the oil and that a constant supply of reactants were available, pseudo zero order rate constants for the initial part of the reaction were evaluated. They showed an Arrhenius relationship with temperature giving an overall apparent activation energy of 110 kJ mol^-1. Extrapolating rate constants to temperatures expected in Diesel engines, and assuming typical droplet sizes end ignition delays, it was shown that thermal cracking of fuels was possible before ignition and that it is likely that these reactions will have a strong influence on the processes leading to ignition. It was also shown that the presence of oxygen greatly increases the rate of thermal cracking.     

THE IMPORTANCE OF PYROLYSIS IN DIESEL IGNITION OF RESIDUAL FUEL OILS

ABSTRACT

Recent attempts to increase yields of distillate fuels from crude oil have resulted in a decline in the ignition quality of residual fuel oils and claims of ignition problems in large marine Diesel engines. This has revived an interest in fundamental studies of the ignition of liquid fuels and in new ways of defining and measuring ignition quality.

As part of an extensive study of the ignition of a range of residual fuels oils and during the development of novel teats of ignition quality it became obvious that thermal cracking of the fuel could play an important part in the pre-ignition chemistry. This paper reports kinetic data from simple experiments performed on the pyrolyses of residual fuel oils. Small samples and high heating rates were used to try to match the conditions inside a Blow-speed Diesel engine. This data has been used to assess the contribution that thermal cracking makes to ignition processes.

Pyrolyses were carried out on a small silica-coated platinum coil in the inlet of a gas chromatograph. Light hydrocarbon pyrolysis products were formed, and the extent and rate of cracking determined at four temperatures.

Assuming that reaction took place on a surface surrounding the oil and that a constant supply of reactants were available, pseudo zero order rate constants for the initial part of the reaction were evaluated. They showed an Arrhenius relationship with temperature giving an overall apparent activation energy of 110 kJ mol^-1. Extrapolating rate constants to temperatures expected in Diesel engines, and assuming typical droplet sizes end ignition delays, it was shown that thermal cracking of fuels was possible before ignition and that it is likely that these reactions will have a strong influence on the processes leading to ignition. It was also shown that the presence of oxygen greatly increases the rate of thermal cracking.