气相色谱法测定喷气燃料的冰点

用气相色谱法测定喷气燃料中C_(12)～C_(16).正构烷烃的总量.然后与用常规法测定的喷气燃料冰点进行关联,利用建立的回归模型,计算出喷气燃料的冰点,计算值与实测值偏差小于±1.5℃.色谱法简单、快速、准确,适用于石化企业生产控制分析.     

高密度烃燃料冰点的DSC法测定

介绍了用差示扫描量热法(DSC)测定高密度烃燃料冰点的原理和方法,并对测试中的主要影响因素进行讨论。结果表明,当高密度烃燃料冰点在-80℃以下时,该方法具有较好的重复性和再现性,可作为高密度烃等低冰点燃料的常规检测方法。     

煤基喷气燃料研究现状及展望

为促进我国喷气燃料的发展,介绍了JP-900、煤基全合成喷气燃料和煤直接液化喷气燃料3种煤基喷气燃料的研究历程和制备方法,对比分析了煤基喷气燃料和传统石油基喷气燃料的理化性能和使用性能,最后对煤基喷气燃料的发展提出了相关建议。JP-900的氮含量和硫含量都很少,具有较高的闪点和较低的冰点,密度高,极性化合物含量很少,其热稳定性和燃烧性能均优于石油基的航空燃料。煤基全合成喷气燃料的热稳定性、润滑性、材料相容性等指标相似或更优于传统石油基喷气燃料Jet A-1。煤直接液化油的组成特点与JP-900相似,具有高密度、高闪点、低冰点和富含环烷烃等特点,但其中的杂原子化合物会显著影响其燃料性能。除煤基全合成喷气燃料外,其他2种煤基喷气燃料还没有投入商业应用。未来应进一步增加煤液化产能,建立健全煤基喷气燃料的试验方法,建立煤基喷气燃料的产品标准,以实现煤基喷气燃料的大规模工业化生产和商业应用。     

喷气燃料中水含量测定技术研究

本文介绍了喷气燃料中超标水含量对飞机运行产生的影响;介绍了新兴的测定手段——温度滴定法,总结对比了几种水含量测定方法的优缺点与适用范围;总结了卡尔费休法和温度滴定法测定实验中的注意事项。得出结论：两方法对3#喷气燃料微量水含量测定结果具有一致性;并对后续该研究中的发展方向提出建议。     

自动颗粒计数法测定喷气燃料污染度仪器对比研究

颗粒污染物是对喷气燃料影响最大危害最大的污染物质,针对颗粒污染物的污染度检测对于保证喷气燃料质量具有重要意义。自动颗粒计数法作为目前运用较为成熟的新型技术,具有操作简便、快速准确的优点。然而针对喷气燃料领域,目前国内还没有形成自动颗粒计数法的试验方法标准。为验证自动颗粒计数法在喷气燃料领域的可行性,论文通过实验和数据整理分析,比较了三型自动颗粒计数器的测定结果,为更好地做好喷气燃料质量监控奠定基础。     

油罐车残存油中元素硫的半定量快速测定方法

油罐车是否污染喷气燃料,使喷气燃料的银片腐蚀不合格,主要是由油罐车内壁残留的元素S含量所决定。研究发现,罐车内壁锈粉与罐底残存油中元素S含量呈一定的相关性。本文采用汞滴法,利用汞滴在不同含量的元素S中变色时间不同这一性质,快速测定残存油中的元素S含量范围,从而可知罐车内壁是否吸附有过高的元素S,为准确判断油罐车是否污染喷气燃料提供重要的依据。     

影响喷气燃料润滑性能的因素探讨

考察了用球柱润滑性评定仪测定喷气燃料润滑性能的影响因素。通过实验可知，温度、环境湿度、抗静电剂、硫化物等因素对喷气燃料润滑性均有影响。     

中红外光谱法测定航空润滑油50-1-4Ф燃料污染水平

对配制的不同3号喷气燃料含量的50-1-4Ф润滑油样品作为航空润滑油燃料污染水平测定的标准模拟油样进行红外光谱分析,选择红外谱图中805~755 cm-1区域作为测定滑油燃料污染水平的定量区域,对此区域峰面积与相应的样品燃料污染水平的相关性进行分析并给出回归方程。结果表明利用傅立叶变换红外光谱法测定航空润滑油的喷气燃料污染水平是可行的,测定结果是可靠的。     

近红外光谱仪快速测定喷气燃料的烯烃含量

采用ZX440近红外多组分油料分析仪建立了喷气燃料烯烃含量的校正模型,对校正模型的准确性进行了验证。分析结果表明,近红外光谱分析可实现对喷气燃料烯烃含量的快速准确测定。     

芳烃捕集阱气相色谱法在航煤总芳烃快速测定中的应用

采用中石化石油化工科学研究院在建的芳烃捕集阱气相色谱法(AGC法)测定永坪炼油厂3#喷气燃料芳烃含量,其与现行FIA法最大偏差为0.15%;同时采用质控样、不同芳烃含量样品对方法的准确性、精密度、适用性进行了考察。实验证明,该方法具有广泛的适用性,准确性和精密度较FIA法有较大提高,单次样品分析时间小于7 min,测试快捷高效,是FIA法测定喷气燃料芳烃含量理想的替代方法。     

Determination of sulfur contaminants in military jet fuels

Military jet fuel samples have been characterized by gas chromatography with a sulfur chemiluminescence detector and a mass spectrometer (GC-SCD-MS). Sixteen distinct organosulfur compounds were quantified in the jet fuel samples. The structures and the concentrations for seven of them are determined in this study. Although the total sulfur content of jet fuel varies from sample to sample, the individual organosulfur distribution remains unchanged for six jet fuel samples obtained over a 4-year period. The two major sulfur compounds are determined to be 2,3-dimethylbenzothiophene and 2,3,7-trimethylbenzothiophene. These two major compounds are determined to be good representative compounds in jet fuel surrogates for computational studies of jet fuel catalysis such as JP-8 reformation.     

Formation of coke in thermal cracking of jet fuel under supercritical conditions

Continuous-flow reactor experiments were carried out to study coke formation from thermal cracking of home-made jet fuel RP-3 under supercritical conditions. The mechanism and precursor of coke forming were analyzed. The starting cracking temperature of RP-3 fuel was determined to be 471.8°C by differential scanning calorimetry (DSC). Temperature-programmed oxidation and scanning electron microscopy (SEM) characterizations of the stressed tubes showed that there are three different coke species including chemisorbed carbon, amorphous carbon and filamentous coke in the solid deposits. More than 90% of coke deposits are carried away by the supercritical fluid, which has strong capabilities of extraction for coke deposits and their precursors. There were 17.1 wt-% of iron and 11.1 wt-% of chromium found on the coke surface detected by energy dispersive spectroscopy (EDS) which suggests carburetion on alloy. RP-3 fuel and its cracking liquids were analyzed by GC-MS,which showed that the content of alkyl benzene and alkyl naphthalene increased evidently in cracking liquids.     

Epoxy paint failure in B-52 fuel tanks: Part II. Influence of DIEGME concentration in the fuel on the failure process

A model has been proposed to explain the failure of the original BMS10-39 epoxy paint on upper vertical surfaces in B-52 fuel tanks. The model involves interaction of the paint with DIEGME, a fuel system ice inhibitor (FSII) in jet fuel, that is distilled from the liquid fuel. In this communication, distillation experiments used to support the model are refined to better match the mass transfer of vapor from fuel in a B-52 fuel tank at close to room temperature. The interaction of these lower temperature distillates with the paint affirms the earlier model. On the basis of these experiments it is proposed that paint failure may be controlled or eliminated by reducing the level of DIEGME in the fuel. Proposed changes in military jet fuel composition are detailed.     

Formation of coke in thermal cracking of jet fuel under supercritical conditions

Continuous-flow reactor experiments were carried out to study coke formation from thermal cracking of home-made jet fuel RP-3 under supercritical conditions. The mechanism and precursor of coke forming were analyzed. The starting cracking temperature of RP-3 fuel was determined to be 471.8°C by differential scanning calorimetry (DSC). Temperature-programmed oxidation and scanning electron microscopy (SEM) characterizations of the stressed tubes showed that there are three different coke species including chemisorbed carbon, amorphous carbon and filamentous coke in the solid deposits. More than 90% of coke deposits are carried away by the supercritical fluid, which has strong capabilities of extraction for coke deposits and their precursors. There were 17.1 wt-% of iron and 11.1 wt-% of chromium found on the coke surface detected by energy dispersive spectroscopy (EDS) which suggests carburetionon alloy. RP-3 fuel and its cracking liquids were analyzed by GC-MS,which showed that the content of alkyl benzene and alkyl naphthalene increased evidently in cracking liquids. __________ Translated from Petrochemical Technology, 2006, 35(12): 1151–1155 [译自:石油化工]     

SHALE OIL HYDROPROCESSING TO PRODUCE SYNTHETIC JET FUELS

The crude shale oil fractions below 343°C available in the United States, (a) Geokinetics, (b) Occidental, (c) Paraho, and (d) Tosco II, were catalytically hydroprocessed at low, medium and high severities. The hydroprocessed oils were fractionated to the jet fuel cuts range of 121-300°C. Shale-oil jet fuels were characterized and compared with petroleum jet fuels to evaluate their suitability as future jet fuel oil substitutes. Nitrogen content in shale-oil jet cuts was in the range of 0.03 to 1.15 wt%. The lowest nitrogen content, 0.03 wt% in high severity Occidental jet fuel, was considerably higher than that of the petroleum jet fuel cuts (1-5 ppm). The sulfur content and mercaptan sulfur content in shale-oil jet fuel was significantly lower than in petroleum jet fuel (total sulfur = 0.3 wt% maximum, mercaptan sulfur = 0.003 wt% maximum), the hydrogen content (13-14wt%) in the shale-oil jet fuel cut was lower than that of petroleum jet fuel (15-16 wt%). The jet fuel distillates, volume percent of the shale-oil and petroleum, that were operated at the same temperatures were comparable; with the exception of the freezing points of the shale-oil fuel cut which were much higher than those of the petroleum jet fuel.     

航煤、柴油色谱模拟蒸馏的应用

介绍了采用气相色谱模拟蒸馏的原理快速测定航煤、柴油的馏程的方法。使用一条具有一定分离度的非极性毛细管色谱柱,将样品通过可程序升温进样口进入色谱柱,在线性程序升温条件下将样品按沸点次序分离,模拟经典实沸点蒸馏测定出馏程;并通过经典手工馏程分析数据,对每一类样品的结果进行修正,建立相对应的样品类型。试验表明,采用气相色谱模拟蒸馏可在8 min内准确、简便地测定出航煤和柴油的馏程。     

A diffusion-relaxation model of pulverized fuel combustion

A model for pulverized fuel combustion with allowance for the microstate of the fuel is proposed. It was shown that the burning of a fuel particle having a microstructure follows the laws of external (diffusion) and internal (relaxation) kinetics. The influence of the diffusion-relaxation mechanism on the burnout time of a fuel particle with a polymeric microstructure, its stressed state, and the pulverized fuel flame length was analyzed. The ranges of pulverized-fuel combustion parameters in which the flame length is determined by the fuel combustion or the gas jet mixing mechanism were distinguished.     

Flame length scaling in a non-premixed turbulent diluted hydrogen jet with coaxial air

The effect of fuel composition on flame length was studied in a non-premixed turbulent diluted hydrogen jet with coaxial air. Because coaxial air entrained in a fuel stream enhances the mixing rate of fuel and air, it substantially reduces flame length. The observed flame length was expressed as a function of the ratio of coaxial air to fuel jet velocity and compared with a theoretical prediction based on the velocity ratio. Four cases of fuel mixed by volume were determined: 100% H₂, 80% H₂/20% N₂, 80% H₂/20% CO₂, and 80% H₂/20% CH₄. In addition, fuel jet air velocity and coaxial air velocity were varied in an attached flame region as u_F = 86-309 m/s and u_A = 7-14 m/s. In this study, we derived a scaling correlation for predicting the flame length in a simple jet with coaxial air using the effective jet diameter in a near-field concept. The experimental results showed that the visible flame length was in good relation to the theoretical prediction. The scaling analysis is also valid for diluted hydrogen jet flames with varied fuel composition, which affects flame length by varying the density of the fuel.     

含不同粒度铝粉的铝/冰燃料的燃烧特性

用微米铝粉逐级取代部分纳米铝粉制备铝/冰燃料,采用表面接触法和高速摄影技术研究了不同粒度铝粉改善铝/冰燃料燃烧特性的效果. 结果表明,随微米铝粉取代量增加,铝/冰燃料燃烧反应速率和剧烈程度均先提高后降低,微米铝粉取代量为30%(w)时,铝/冰燃料最高升温速率达6062.24℃/s,是纯纳米铝/冰燃料的3.8倍. 用微米铝粉取代部分纳米铝粉均不同程度提高铝/冰燃料的燃面传播速率,微米铝粉取代量约为20%(w)时燃烧性能最佳,燃面传播速率较纯纳米铝/冰燃料提高57.8%. 在分析实验结果的基础上,建立了铝/冰燃料的燃烧火焰模型.     

Effect of Particle Impact on Surface Cleaning Using Dry Ice Jet

The removal of particulate contaminants adhering to a surface has been investigated using a dry ice blasting system. Monosized spherical latex particles of micron and submicron sizes were used as particulate contaminants, while the dry ice jet was produced by the thermal expansion of liquid carbon dioxide (CO₂). Removal of the contaminants was observed in situ using a high-speed microscope camera and quantified through digital image analysis. The experimental results showed that dry ice blasting performs well for surface cleaning, which is attributed to the collision of the dry ice particles with the contaminants. For submicron-sized contaminants, a lower temperature jet was required in order to produce a larger number of dry ice particles to enhance the removal efficiency. The removal efficiency increased with an increase of the jet pressure on the surface. In addition, a theoretical analysis of the moments of forces caused by particle impact and aerodynamic drag showed that particle impact is primarily responsible for removal. Furthermore, the effect of the dry ice cleaning was visually observed by applying it to the removal of a film resin covering a surface.