喷气燃料加氢精制银片腐蚀不合格问题探析

通过加氢精制技术后的喷气燃料在改善油品质量方面起着十分重要的作用,但也有一些新的问题伴随而生。近年来,加氢喷气燃料银片腐蚀不合格问题日益突出。本文对喷气燃料加氢精制后遇到的银片腐蚀不合格原因进行了分析,得出活性硫化物和细菌是造成银片腐蚀不合格的主要因素,并为解决这一问题提出了对策。     

喷气燃料银片腐蚀机理及解决方法

综述了喷气燃料银片腐蚀机理及解决方法。结果发现,引起银片腐蚀试验不合格的原因是活性硫化物,主要是单质硫。采用补充精制工艺,可以解决喷气燃料的银片腐蚀问题,对产品的相关性能没有影响。     

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。     

美国军用喷气燃料的品种规格与发展

对美军喷气燃料的发展历程进行了综合阐述,分析了美军在不同历史时期使用的不同规格的喷气燃料,对影响喷气燃料规格变化的因素进行了综合分析,揭示了喷气燃料技术规格指标变化与装备技术发展之间的互相促进关系。提出了我喷气燃料发展可以借鉴的思路,对于提高我国新型喷气燃料生产的针对性和研制方向具有一定的借鉴意义。     

喷气燃料中的水分溶解研究

介绍了水在喷气燃料中的三种存在形式以及形成原因,讨论了湿度、温度以及燃料组分等因素对喷气燃料中水分溶解的影响,提出应加强对低温条件下喷气燃料中水分溶解行为的研究,这对提高飞机的飞行安全性能具有重要意义。     

碱氮对喷气燃料水分离指数的影响

对3#喷气燃料的生产数据进行统计分析,确定了影响喷气燃料添加抗静电剂后水分离指数下降的关键因素是原料油中携带的碱性氮化物。指出加氢装置操作参数和加氢催化剂的脱氮活性都决定碱氮脱除率,从而影响喷气燃料水分离指数的稳定。当处理碱性氮化物含量较高的原料时,需要选用脱氮率更好的加氢催化剂,从而保证喷气燃料水分离指数稳定。     

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。     

喷气燃料中微生物污染及检测方法概述

微生物污染会降低燃料品质、影响燃料供给系统正常工作、增加燃料腐蚀性,是影响燃料储存和飞机飞行安全的重要因素。从喷气燃料中的特征微生物、微生物污染的危害和喷气燃料中微生物检测方法三个方面综述了近几年喷气燃料中微生物污染问题研究进展,分析了目前仍然存在的问题,提出了下步研究的重点方向。     

喷气燃料氢含量的估算

利用GC/MS分析了30种喷气燃料的烃族组成结果,详细确定了每种燃料的链烷烃、一环环烷烃、二环环烷烃、三环环烷烃、单环芳烃和双环芳烃等组成。根据ASTM D2887利用气相色谱法测定喷气燃料的馏程。根据其烃族组成和馏程建立了一种燃料氢含量的估算方法,并对该估算方法的准确度进行分析。结果表明,利用烃族组成及模拟蒸馏中沸点的数据估算氢含量的方法与元素分析法测定结果一致,可利用该方法对喷气燃料氢含量进行估算。     

对我国喷气燃料进出口的特点分析及建议

介绍我国喷气燃料生产、消费及供求关系发展形势,并对我国喷气燃料进出口业务进行分析,提出喷气燃料进口与来料加工出口以及供港、澳和越南的喷气燃料统筹经营的模式,使中国石化及中国航油在经济上更为有益.     

Catalytic activity of iron in the water vapour gasification of sulphur-containing cokes

The influence of sulphur on the catalytic activity of iron in gasification with H₂-H₂O mixtures at different total pressures and temperatures was studied with model cokes of various sulphur contents, prepared by copyrolysis of PVC and elemental sulphur at 600 °C. Sulphur represents a strong poison which may completely inhibit the catalytic activity of iron, owing to the presence of extremely stable sulphur surface compounds. The inhibition may partly be compensated by increase of pressure or temperature. The beneficial effect of pressure results from hydrodesulphurization of the cokes in the early stages of gasification, especially at low water vapour partial pressures. High temperatures effect a reduction of the sulphur surface compounds. A general reaction scheme is proposed and it is concluded that gradual inhibition of the catalytic activity of iron is caused by partial blocking of active centres on the iron surfac.     

THE OXIDATION OF CERAMIC WARES DURING FIRING. V.—A QUANTITATIVE STUDY OF THE NATURE OF SULPHUR EVOLUTION IN KILN-FIRING.1 (Part I)

The absorption and evolution of sulphur gases in four industrial brick kilns were studied. Curves are shown giving the cumulative amounts of sulphur entering and leaving the kilns, and of the kiln content of sulphur. Surfaces and hearts of draw trials are analyzed to show the progressive change in nature of the sulphur compounds in the ware.     

COSMO-RS based predictions for the desulphurization of diesel oil using ionic liquids: Effect of cation and anion combination

Ionic Liquids ILs provide an important alternative in removing aromatic sulphur compounds by Liquid-Liquid Extraction (LLE). A total of 28 anions and 6 cations resulting in 168 possible combinations were screened via COSMO-RS (COnductor Like Screening MOdel for Real Solvents). Initially benchmarking was performed to predict the infinite dilution activity coefficients of thiophene in ionic liquids. Comparison with literature values involving 8 ILs with 20 points gave the average root mean square deviation (RMS) to be 11%. Thereafter artificial simulated diesel, aromatic sulphur compound and the cation and anion combination was used to predict the capacity (C) and selectivity (S) at infinite dilution. In general the selectivities were found to decrease in the following order: thiophene (4-24) > benzothiophene (2-12)> dibenzothiophene (1-7). The different hetero atom (N,S,O) and its location in the cation structure strongly influenced the selectivity and capacity at infinite dilution for all the three aromatic sulphur compounds. It was found that the cation without the aromatic ring combined with anions having sterical shielding effect such as [SCN], [CH₃SO₃], [CH₃COO], [Cl], and [Br] proved to be the most favourable IL for desulphurization. [EMMOR][SCN] proved to be the most viable IL for the removal of all the three aromatic sulphur compounds.     

Reductive pyrolysis of Miocene-aged lignite lithotypes using MS and GC/MS detection systems for analysis of organic sulphur groups

The atmospheric pressure temperature programmed reduction (AP-TPR) technique, an approach for organic sulphur speciation, was extended by mass spectral detection. The coupling gave ground for precise assignment of sulphur compounds in flue gases of lignite lithotypes pyrolyzed in H₂ atmosphere. A broad range of sulphur compounds was determined, i.e. thiols, dimethylsulphide, dimethyldisulphide, CS₂, thiophenes, benzothiophenes and their alkylated homologues. Certain peculiarities in organic sulphur distribution in lithotypes under study were noticed. Humovitrain was the lithotype with the highest organic sulphur content. A preponderance of aliphatic sulphur, thiols and dimethylsulfides were determined for both homogeneous lithotypes (xylain and humovitrain). In humovitrain, additionally thiophenes were also identified. For heterogeneous lithotypes, liptain and humoclarain, a dominance of disulphides and an almost lack of sulphides was observed. This is an indication that with coalification a gradual loss of aliphatic sulphur functions has proceeded, where more resistant disulphides sulphur bridges turned out to be present. Thiophenes are the most abundant aromatic structures, dominating in humoclarain. Some amounts of oxidised organic sulphur compounds (1% up to 4.1% of S_org) were semi-quantitative determined in lithotypes using AP-TPR-MS.     

Mechanism of the hydrogen-sulphidepromoted cleavage of the coal model compounds: diphenyl ether,diphenylmethane and bibenzyl

Hydrogen sulphide is shown to cleave the model coal compounds: diphenyl ether, diphenylmethane and bibenzyl with the major products being phenol and thiophenol, toluene and thiophenol, and toluene, respectively. These reactions were determined to be radical in nature. The sulphur which incorporated into diphenyl ether and diphenylmethane forming thiophenol was determined to reside ultimately at the ipso position. The cleavage of all three model compounds was inhibited by the presence of 316 stainless steel. The nature of the iron sulphides produced and the amount of H₂S reacted were determined. It is concluded that 316 stainless steel and tetralin act as sulphur radical scavengers. In the absence of steel or tetralin, the conversions of the model compounds occur by radical chain mechanisms in which H₂S acts as a reagent.     

Determination of sulphur heterocycles in selected synfuels

A fractionation method for isolating the polycyclic aromatic sulphur heterocycles from complex mixtures of polycyclic aromatic compounds was evaluated with respect to recovery for selected standard compounds. It was found that recovery varied from 0 to 70% depending on the structure of the compound. Although quantitative recovery for all components was not obtained, isolation of the sulphur heterocycle fractions has allowed the identification of many new sulphur compounds previously not identified in coal liquids and shale oils. Capillary column gas chromatography with flame photometric detection and mass spectrometry were used for the identification of individual sulphur heterocycles.     

灰关联模式在评估土壤腐蚀性中的应用

土壤腐蚀性等级与埋地管道的安全运行密切相关,科学、准确的评价土壤腐蚀性是管道安全运行管理的重要组成部分。由于影响土壤腐蚀的因素众多,仅仅以土壤电阻率来评价土壤腐蚀性既不准确也不科学。在此应用灰关联模式对土壤腐蚀性指标进行评估,建立了灰关联标准模式,得出了灰关联系数与灰关联度,并通过实际工程算例证明了方法的可行性与科学性,证明了灰关联模式评估在土壤腐蚀性评价这一复杂系统中的适用性。     

Comparative evaluation of modified whetlerites and impregnated carbons for sulphur mustard degradation

Versatile adsorbents were prepared by modifying whetlerite carbon for intended application against both non-persistent and persistent chemical warfare agents. Whetlerite carbon was modified by impregnating with basic inorganic compounds such as sodium hydroxide, potassium carbonate, sodium carbonate, cesium carbonate, etc. and oxidizing inorganic compounds such as ammonium heptamolybdate, ceric ammonium nitrate, etc. These carbons were explored for their reactivity against sulphur mustard and data was compared with that of impregnated carbons consisted of above basic and oxidizing compounds. On modified whetlerites and impregnated carbons comprised of basic compounds, sulphur mustard was transformed into hemisulphur mustard, thiodiglycol, vinyl-2-chloroethyl sulphide, divinyl sulphide, etc. On those comprised of oxidizing compounds sulphur mustard was converted into sulphur mustard sulphoxide.     

Deep desulphurization of gasoline and diesel fuels using non-hydrogen consuming techniques

Desulphurization of FCC gasoline and diesel fuels has been investigated by chemical oxidation of sulphur containing compounds with hydrogen peroxide in the presence of an acid catalyst such as formic acid and acetic acid, followed by extraction of the oxidized compounds using acetonitrile. Oxidative desulphurization (ODS) of diesel fuel was found to be very promising approach for the reduction of up to 92% of sulphur at low temperature (50 °C) and atmospheric pressure. The direct extraction of diesel oil without any oxidation has resulted in about 45% sulphur removal, however such direct extraction also removed other aromatic hydrocarbons and affected the yield. The ODS is not successful with FCC gasoline due to the high olefinic content that tends to react with hydrogen peroxide to form epoxides. GC–MS technique was used to identify the sulphones during the oxidation of thiophenes. This study recommends that the oxidation extraction technique be used as an additional process to the hydrodesulphurization to enable the refiners to meet the future environmental sulphur regulations. The conventional hydrodesulphurization can be used to lower the sulphur content to few hundreds ppm. Then, the oxidation/extraction approach needs to be used to go for ultra-deep desulphurization as it may provide better mean and cost effective way in order to meet the future sulphur environmental requirements.     

Sulphur in Assam coal

Research carried out on sulphur in Assam coals are reviewed. It is intended to provide a general overview with some recent advances on the forms of sulphur in these coals and their desulphurization and recovery in the forms of elemental sulphur or useful compounds. Greater emphasis is given on a new form of sulphur, i.e., secondary sulphur, in Assam coals. Studies on sulphur in Assam coals would be potentially useful in coal utilization.