柴油对乙烯-醋酸乙烯酯降凝剂感受性的研究

用色-质联用方法对经纯化处理的4种国内外柴油降凝剂进行分析,确定了它们纯化后所得聚合物均为乙烯-醋酸乙烯酯。对柴油组分及其调合柴油进行降凝剂感受性试验,结果表明,乙烯-醋酸乙烯酯降凝剂对柴油具有较好的降凝效果,对加氢柴油及其调合柴油具有较好的降低冷滤点效果,当加剂量为500 ?g/g时,加入降凝剂B能使加氢柴油的冷滤点降低12 ℃,加入降凝剂C可使-20号调合柴油的冷滤点降低20 ℃。分析柴油的正构烷烃含量及其碳数分布,结果表明,正构烷烃含量低且具有较高含量低碳数正构烷烃柴油的低温性质较好;正构烷烃含量低、碳数分布宽、含有少量高碳数正构烷烃的柴油的加剂感受性较好。     

柴油正构烷烃碳数分布的统计学分析及其对流动改进剂感受性的影响

对五种柴油的正构烷烃含量和碳数分布作了测定,并从统计学角度进行了详细的描述和分析。在显著性水平为0．10时,五种柴油的正构烷烃的碳数分布均符合正态分布。根据正态分布的分析,计算了正构烷烃的平均相对分子质量0和碳数分布方差σ2。σ2较小时,柴油对低温流动改进剂的感受性较差。检验统计量X^2可以反映柴油正构烷烃符合正态分布的程度,当油样中的正构烷烃分布不太符合正态分布的时候,其对各种流动改进剂的感受性较差。     

调和柴油低温性能影响因素的考察

通过冷冻抽吸试验分离调和柴油中的正构烷烃，分析正构烷烃碳数分布，考察了影响调和柴油低温性能的主要因素，从而得出结论：正构烷烃性质是影响调和柴油低温性能的主要因素。     

α-甲基丙烯酸混合醇酯-马来酸酐-苯乙烯降凝剂的制备及其降滤效果评价

采用自由基溶液聚合法合成了α-甲基丙烯酸混合醇酯(AE)-马来酸酐(MA)-苯乙烯(St)三元共聚物(AMS)降凝剂;考察了AMS的最佳聚合条件及其对中原0#柴油和燕化0#柴油的降滤效果;用GC技术分析了中原0#柴油和燕化0#柴油中正构烷烃碳数的分布;用1HNMR技术表征了AE和AMS的结构。AMS的最佳聚合条件为:n(AE)∶n(MA)∶n(St)=3∶1∶1,时间5h,温度80℃;AMS降凝剂的适宜添加量(占柴油的质量分数)为0.08%,此时中原0#柴油和燕化0#柴油的冷滤点降幅分别为4℃和6℃。对于正构烷烃含量较低、正构烷烃碳数分布较宽且较均匀的柴油,使用AMS降凝剂时,降滤效果较好。     

柴油组成对低温流动性改进剂T1804的感受性研究

本文将0.1wt%的低温流动性改进剂T1804添加到不同炼厂的0#柴油中,测试其冷滤点降低幅度。通过对不同炼厂0#柴油的烃族组成、正构烷烃分布、馏程的分析,讨论了它们与柴油感受性的关系。柴油的感受性是烃族各组成的综合作用;馏程宽大于是100℃,则正构烷烃碳数分布宽,感受性好。     

马来酸酐-丙烯酸十八醇酯-醋酸乙烯酯三元共聚物柴油降凝剂的合成及其性能评价

实验以马来酸酐(MA)、丙烯酸十八醇酯(AE)、醋酸乙烯酯(VA)为原料,合成三元聚合物MAV。考察了MAV的最佳反应条件及其对柴油的降滤效果,分析了4种不同柴油正构烷烃碳数分布,测试了MAV对4种不同柴油的降滤效果,红外光谱(IR)表征了AE单体及MAV共聚物。实验结果表明,MAV三元聚合物的最佳合成条件为:n(马来酸酐):n(丙烯酸十八醇酯):n(醋酸乙烯酯)=1:1:1,聚合温度为80℃,聚合时间为4 h,引发剂用量为1.0%。MAV对四种不同柴油的降滤效果不同,对加氢柴油有较好的适用性,对直馏柴油和催化裂化柴油的降滤效果较差。当加剂量为0.3%时,可将燕化加氢柴油的冷滤点降低3℃。MAV柴油降凝剂对正构烷烃分布较宽且含量低的柴油感受性较好,对正构烷烃分布窄且含量高,特别是高碳数正构烷烃含量较高的柴油几乎无降滤效果。     

柴油组成对低温流动性改进剂T1804的感受性研究

本文将0．1wt％的低温流动性改进剂T1804添加到不同炼厂的0#柴油中，测试其冷滤点降低幅度。通过对不同炼厂0#柴油的烃族组成、正构烷烃分布、馏程的分析，讨论了它们与柴油感受性的关系。柴油的感受性是烃族各组成的综合作用；馏程宽大于是100℃，则正构烷烃碳数分布宽，感受性好。     

AVS型柴油降凝剂的性能

通过自由基聚合法合成了四种不同烷基链长的丙烯酸烷基酯-醋酸乙烯酯-苯乙烯三元共聚物,测定了共聚物对柴油的降凝降滤效果,用气相色谱仪测定了柴油中正构烷烃的含量和分布,用高级流变仪和光学显微镜研究了柴油加降凝剂和未加降凝剂的流变行为和结晶行为。结果表明:烷基链长与柴油中正构烷烃的平均碳数接近的降凝剂降凝效果最好,可使凝点降低12℃,而使柴油中蜡晶变得更分散更均匀的降凝剂降滤效果最好,可使冷滤点降低4℃;蜡晶的大小、形状和聚集状态直接影响柴油的冷滤点,而三维网状结构的形成对柴油的凝点起决定性的作用,好的柴油降凝剂应该既不利于三维网状结构的形成,又不使蜡晶变的太大或聚集成太大的簇状结构。     

柴油中正构烷烃碳数分布与柴油流动改进剂的分子设计

 为了研究柴油中正构烷烃碳数分布与低温流动改进剂(DFI)的结构和性能之间的关系,测定了8种柴油的正构烷烃含量及其碳数分布,并从统计学角度进行了详细的描述和分析,在显著性水平α =0.10下,计算得到了柴油中正构烷烃的平均相对分子质量、碳数分布方差和检验统计量χ²。通过比较多种低温流动改进剂在柴油中的降冷滤点(△T_CFPP)效果,发现流动改进剂对正构烷烃含量高、正构烷烃碳数分布方差较小、检验统计量χ²较大的柴油降冷滤点效果较差。流动改进剂对柴油降冷滤点效果与其分子中侧链长度和与其相对分子质量分布有关,因此流动改进剂分子设计应着眼于其结构和相对分子质量分布是否与柴油正构烷烃分布匹配。     

柴油降凝剂与柴油组成的感受性研究

通过红外光谱法确定降凝剂的主要成分为聚乙烯-醋酸乙烯酯。对来自黑龙江、大连、吉林的0号柴油(依次编号为1~3)进行降凝剂感受性实验。结果表明,聚乙烯-醋酸乙烯酯降凝剂对柴油的感受性较好,可使1~3号柴油的凝点分别降低31、9、26℃,冷滤点分别降低18、12、21℃。2号柴油总正构烷烃含量（17.74%）高于1号（14.29%）和3号（13.03%）柴油,其C10~C19含量占总含量的87.2%。2号柴油的正构烷烃含量较高,因此其降凝效果较1、3号差。采用了偏光显微镜、差示扫描量热法（DSC）以及X射线衍射法（XRD）研究了降凝剂对蜡晶形貌和热力学的影响。加入降凝剂后,蜡晶颗粒由不规则的细长棒状变成细小的类球状。DSC分析结果表明,加剂后1、2号柴油析蜡高峰值温度由-1.46、-2.38升至0.46、2.41℃,结晶峰斜率均变小,在相变过程的固-液相变能（ΔH）绝对值由3278、5.283降至3.459、1.737 J/g。降凝剂通过改变固-液相变能来改变柴油的低温流动性。XRD测试结果表明,降凝剂与柴油发生了共晶作用,蜡晶聚集方式改变,单一晶型生长速率降低。综合偏光显微镜与DSC以及XRD结果说明,降凝剂的降凝机理是成核理论与共晶理论的共同作用。     

Impact of Alkyl Methacrylate-Maleic Anhydride Copolymers as Pour Point Depressant on Crystallization Behavior of Simulated Diesel Fuel

Abstract

The alkyl methacrylate-maleic anhydride copolymer (RMC-MA) is widely used as a pour point depressant (PPD). In order to develop more efficient RMC-MA, it is necessary to study the crystallization behavior of n-alkanes when adding RMC-MA to diesel fuel. In this study, RMC-MA was prepared by the reaction of long-chain alkyl methacrylate and maleic anhydride. The simulated diesel fuel before and after adding C₁₄MC-MA were filtered at the cold filter plugging point (CFPP) in a manual CFPP apparatus. Extensive measurements of the variation of the composition of n-alkanes were done by gas chromatography and the results were compared. The experimental results show that

1. the recovery ratios of the simulated diesel fuel and fuel with additive are 98.6 and 98.1%, respectively; and

2. the distribution of the concentrations of n-alkanes in the filtrate is basically similar to that of the simulated fuel. The distribution of concentrations of n-alkanes in the precipitate exhibits a slight decrease in the concentration of low carbon number n-alkanes concomitant with an increase in the concentration of high carbon number n-alkanes;

3. The crystallinity of n-alkanes in simulated diesel fuel and fuel with additive increase with an increase of n-alkanes number.

With the C₁₄MC-MA copolymers added into simulated diesel fuel, the crystallinity of octadecane and eicosane began to decline, and n-alkanes with carbon number from 12 to 16 show a tiny increased trend.     

n-Alkane Distributions,Wax Settling Levels,and Responses to Flow Improvers in Diesel Distillations

The authors have statistically analyzed the relationship between the distributions of n-alkanes in diesels and the response of the diesel flow improver (DFI) to explore the reasons for the performance variation of DFIs. Diesel with a small n-alkane distribution variance showed a weak sensitivity to the DFI. The wax settling levels of the diesels were calculated at low temperature using a thermodynamic model and were found to increase as the n-alkane distribution variance decreased. Higher levels of settled crystals led to the poor performance of the DFI in the diesel with a small n-alkane distribution variance.     

STUDY OF THE TEMPERATURE AND ENTHALPY OF THERMALLY INDUCED PHASE-TRANSITIONS IN n-ALKANES, THEIR MIXTURES AND FISCHER-TROPSCH WAXES

A precise determination of the temperatures and enthalpies of thermally induced various phases of n-alkanes, especially those having the molecular weights in the petroleum wax range, have been done by using a differential scanning calorimeter (DSC). These phase transitional parameters are shown to be dependent on the rate of heating/cooling, particularly on the faster rates. Also, the parameters measured during heating cycle (melting) differ from those obtained during the cooling cycle (crystallization). The typical shape of the solid-solid transition curve in the DSC thermograms(cooling cycle) of even n-alkanes readily distinguishes these from the odd n-alkanes, which is greately influenced by the increase in the carbon numbers in the chain (n-C₃₄ and beyond) and the purity of the sample.High molecular weight n-alkanes also showed instability in the structures at the phase transitions

The formation of solid solutions of n-alkanes have been studied by measuring phase transitional parameters and studying nature of the DSC thermograms of various binary and multicomponent mixtures of n-tetracosane (n-C₂₄) with other n-alkanes. It is observed that the immiscibility between two n-alkanes of the binary mixture begins when chain-length difference between them is more than four carbon atoms. In between the two extremes of solid solution and eutectic formations, there also existed the partial miscibility of two n-alkanes, particularly at high temperatures

The DSC thermograms of multicomponent n-alkane mixtures and Fischer-Tropsch waxes revealed that perfect solid solution is formed when the involved n-alkanes have carbon number very close to each other or the carbon number distribution is in a narrow range with smaller chain n-alkanes dominating.     

黔北坳陷高演化烃源岩中正构烷烃单体烃碳同位素组成

借助于色谱-质谱和单体烃碳同位素分析技术,对黔北坳陷高演化海相烃源岩和黔南坳陷虎47井原油中各类生物标志物和正构烷烃的单体烃碳同位素组成进行了系统分析。不同层位烃源岩中常用的甾、萜烷的分布与组成呈现明显趋同现象,因而失去了其原有的地球化学意义和实用性。虎47井原油中三环萜烷系列和孕甾烷系列丰富,但C_27-35藿烷系列和C_27-29甾烷系列的丰度极低,显示生油窗晚期的产物特征。绝大多数烃源岩中nC_16-28正构烷烃系列呈现以nC₂₀或nC₂₁为低谷的前、后2个峰群的分布模式,但其单体烃碳同位素组成则十分接近,它们的δ¹³C值介于-28‰~-31‰之间,呈负偏态变化,即随碳数增加其δ¹³C值变小,且这一特征不受正构烷烃系列分布特征的影响,表明高演化烃源岩中特殊的正构烷烃系列分布模式是客观地球化学现象。虎47井原油中正构烷烃的单体烃碳同位素组成也呈负偏态变化,但其δ¹³C值较高演化烃源岩中的轻约3‰,这可能与有机质热演化过程中的碳同位素分馏效应有关。因此,在利用正构烷烃的单体烃碳同位素组成开展油源对比时,所用样品的成熟度应该匹配。     

STUDY OF THE TEMPERATURE AND ENTHALPY OF THERMALLY INDUCED PHASE-TRANSITIONS IN n-ALKANES,THEIR MIXTURES AND FISCHER-TROPSCH WAXES

ABSTRACT

A precise determination of the temperatures and enthalpies of thermally induced various phases of n-alkanes, especially those having the molecular weights in the petroleum wax range, have been done by using a differential scanning calorimeter (DSC). These phase transitional parameters are shown to be dependent on the rate of heating/cooling, particularly on the faster rates. Also, the parameters measured during heating cycle (melting) differ from those obtained during the cooling cycle (crystallization). The typical shape of the solid-solid transition curve in the DSC thermograms(cooling cycle) of even n-alkanes readily distinguishes these from the odd n-alkanes, which is greately influenced by the increase in the carbon numbers in the chain (n-C₃₄ and beyond) and the purity of the sample.High molecular weight n-alkanes also showed instability in the structures at the phase transitions

The formation of solid solutions of n-alkanes have been studied by measuring phase transitional parameters and studying nature of the DSC thermograms of various binary and multicomponent mixtures of n-tetracosane (n-C₂₄) with other n-alkanes. It is observed that the immiscibility between two n-alkanes of the binary mixture begins when chain-length difference between them is more than four carbon atoms. In between the two extremes of solid solution and eutectic formations, there also existed the partial miscibility of two n-alkanes, particularly at high temperatures

The DSC thermograms of multicomponent n-alkane mixtures and Fischer-Tropsch waxes revealed that perfect solid solution is formed when the involved n-alkanes have carbon number very close to each other or the carbon number distribution is in a narrow range with smaller chain n-alkanes dominating.     

应用拓扑指数计算润滑油馏分正构烷烃熔点

在分子图的距离矩阵和邻接矩阵基础上对润滑油馏分正构烷烃分子的拓扑指数进行了计算，并以Balaban中心指数的计算为例进行说明。求得C20～C44正构烷烃的B指数和J指数，并以C20～C44正构烷烃的熔点与其相关的拓扑指数进行多元线性拟合为例说明其应用。     

羌塘盆地羌资2井布曲组碳酸盐岩生物标志物特征及意义

首次报道了藏北羌塘盆地羌资2井中侏罗统布曲组海相碳酸盐岩生物标志化合物特征,该层位含有丰富的正烷烃、类异戊二烯烷烃和萜甾类化合物。正烷烃形态为单峰和双峰并存、以单峰形态占优势,主碳峰以nC₁₇,nC₂₀为主,次为nC₁₈,nC₁₅,nC₁₆,轻烃组分占有绝对优势;OEP值介于0.37~1.14之间,平均值为0.89,无明显的奇偶优势分布;Pr/Ph值介于0.56~1.03之间,平均值为0.75,具有明显的植烷优势。萜烷相对丰度为五环三萜烷>三环萜烷>四环萜烷,伽马蜡烷普遍存在,但相对含量较低;甾烷主要为规则甾烷,少量孕甾烷,规则甾烷∑(C₂₇+C₂₈)>∑C₂₉,∑C₂₇/∑C₂₉介于0.67~1.22之间,显示弱的C₂₇甾烷优势或弱的C₂₉甾烷优势。有机质母质主要来源于藻类等低等水生生物,不能确定是否有陆生高等植物输入。成熟度参数和镜质体反射率均显示碳酸盐岩处于成熟阶段。碳酸盐岩沉积环境总体为缺氧还原—弱还原的海相环境,海水盐度基本正常。     

塔里木盆地下古生界生物标志物分布与沉积环境的关系

塔里木盆地下古生界生物标志物分布与沉积环境有关,反映了藻类和微生物输入的特征。寒武系和奥陶系生物标志物分布具有异同点。塔里木盆地奥陶系与全球奥陶系生物标志物分布的差异反映了不同的生物输入。     

n-Nonane hydroisomerization over hierarchical SAPO-11-based catalysts with sodium dodecylbenzene sulfonate as a dispersant

To enhance the gasoline octane number,low-octane linear n-alkanes should be converted into their high-octane di-branched isomers via n-alkane hydroisomerization...