柴油对流动改进剂感受性差异的原因表征与分析

柴油对低温流动改进剂具有较高的选择性。流动改进剂对不同的炼油厂、不同原油以及不同的加工工艺炼制的柴油的感受性和降冷滤效果截然不同。主要是由柴油的化学组成决定。一般认为，柴油中正构烷烃的摩尔分数和分布是影响其低温流动改进剂使用效果的主要因素。正构烷烃摩尔分数越低，碳数分布越广，添加低温流动改进剂效果越好；此外，柴油中所含的单环芳烃是高碳数烷烃的优良溶剂，其摩尔分数越高，柴油低温蜡析出量越少，加低温流动改进剂效果越好。     

复合改性聚丙烯酸酯柴油低温流动改进剂

合成了改性聚丙烯酸高级酯(PADE)和一种新的蜡晶分散剂3,6-氧桥-1,2,3,6-四氢苯-1,2-二甲酸高级酯/酰胺(EBTD),测试了对0#柴油的低温流动性能的改进效果。结果表明,PADE对蜡晶具有较好的分散作用,能有效地降低燕山、大连、辽河0#柴油的冷滤点,冷滤点降幅为7~10℃;对大庆0#柴油的感受性也较显著,与EBTD复合有增效作用,二者复配后能较好的改善大庆0#柴油的低温流动性能,可以使大庆0#柴油冷滤点降低7~8℃。     

使用流动改进剂柴油的低温流变性研究

研究了柴油在加入柴油低温流动改进剂前后的低温流变性能。结果表明：柴油的浊点与冷滤点之间的温度区间是柴油表观粘度的突跃范围,是解决柴油低温流动性的重点;自制的WW－1型柴油低温流动改进剂的加入降低了低温下柴油的表观粘度的改善了柴油的低温流变性能。     

生物柴油调合对其低温流动性能的改善

为了了解生物柴油中脂肪酸甲酯组成对其低温流动性能的影响,探索改善其流动性能的方法,以大豆油、花生油和牛油为原料合成了大豆油甲酯、花生油甲酯和牛油甲酯,测定了它们的脂肪酸甲酯组成和低温流动性能.结果表明,长碳链饱和脂肪酸甲酯的含量是影响生物柴油低温流动性能的主要因素.通过对混合生物柴油流动性能的测定,发现可以通过不同来源...     

大豆油生物柴油低温流动性能影响的研究

以大豆油为原料采用碱催化酯交换法合成生物柴油，测定了其酸值、游离甘油、总甘油、灰分、黏度和磷含量等指标。实验表明,共存的甲醇、水分和甘油酯对生物柴油的低温流动性能影响极少，饱和脂肪酸甲酯的同时析出对生物柴油低温流动性能起关键作用。考察了5种柴油降凝剂、0号和20号柴油以及乙醇对生物柴油低温流动性能的影响。0号柴油有效地改善生物柴油黏度，但对其低温流动性能影响不大。20号柴油和乙醇能显著降低生物柴油的凝点、倾点、冷滤点和黏度。其中3种降凝剂有效降低生物柴油的凝点和倾点，1种降凝剂能小幅度改善冷滤点，5种降凝剂都能使生物柴油的黏度小幅上升。     

柴油降凝剂的合成及性能研究

合成了新型聚合物型柴油降凝剂,并采用红外光谱对聚合物进行了表征。X射线衍射技术对不同降凝剂的结晶性能分析表明,聚合物的结晶性能差别很大,结晶度不同,蜡晶分散效果不同。同时发现,当两者结晶性能状态匹配时蜡晶分散效果变好,降凝性能最佳,并由柴油体系降凝性能证实。     

原子力显微镜原位观察球晶界面上片晶的生长

当结晶聚合物由熔融冷却或从浓溶液中析出结晶时 ,在不存在应力和流动的情况下 ,一般形成球晶 .球晶在一定的生长时期内呈现球形外观 ,在偏光显微镜下通常呈现Maltese黑十字消光图样 .球晶作为一种常见的结晶形态 ,由片晶堆积而成[1,2 ] .Keith和Padden认为形成球晶的体系包含杂质和聚合物链 ,由于杂质在片晶生长界面的富集导致片晶产生小角度分叉 ,这样片晶能填满球状的空间[1,2 ] .近年来的研究表明球晶是由一个片晶开始生长 ,片晶在生长过程中不断的诱导成核使片晶分叉 ,首先形成片晶捆束 ,然后片晶向各个方向发散生长 ,最终形成球晶[3…     

柴油低温流动性改进剂的研制及性能评价 Ⅰ. 低温流动性改进剂对柴油的感受性

在分析胜利石化总厂 0 #柴油和齐鲁石化 0 #柴油的烃族组成、蜡碳分布的基础上 ,进行分子设计 ,研制出一种柴油低温流动性改进剂。它主要由具有一定粘度的三元共聚物组成。实验结果表明 ,这种柴油低温流动性改进剂能十分有效地提高胜利石化总厂 0 #柴油的低温使用性能 ,而胜利石化 0 #柴油对目前国内外其它低温流动性改进剂的感受性较差。     

大柴旦富硼浓缩盐卤中硼酸镁盐稀释结晶动力学

采用动力学法研究了富硼浓缩盐卤稀释过程硼酸镁盐的结晶动力学,重点探讨了温度、稀释比和硼浓度对结晶过程的影响。利用单纯形优化法配合Runge-Kutta微分方程组数值解法对实验数据进行拟合,给出了结晶动力学方程和结晶速率。结果表明,低温、高硼浓度和中间稀释比有利于硼酸镁盐的结晶析出,最优条件下析硼率(以B_2O_3计)高达88%;结晶速率随硼浓度的增加和温度的降低快速增大;反应级数表明稀释结晶过程硼酸镁盐结晶主要受多核表面反应控制,同时提出了结晶相转化机理。     

降凝剂对蜡油中蜡析出与溶解影响的物理化学研究

用DSC热分析仪研究了合成蜡油的加热与冷却过程,测定了蜡油在不同蜡浓度下,添加降凝剂前后的平衡蜡溶点和析蜡点以及溶解度和饱和度,并进行了热力学分析.结果表明,含蜡油的平衡蜡溶点高于平衡析蜡点,降凝剂使平衡蜡溶点进一步升高,析蜡点进一步降低,导致含蜡油凝点较大幅度降低.在实验浓度和温度范围内,该过程符合Van′tHoff方程,降凝剂使蜡的溶解焓和溶解熵增大,析出焓和析出熵减少.降凝剂提高了蜡晶析出的临界半径,增大了成核位垒,使蜡晶析出困难.     

爪形大分子CTC-NO对柴油蜡晶结构和形态的影响

考察了爪形大分子CTC-NO(柠檬酸-1,4-丁二醇-柠檬酸-环烷酸-十八醇)对不同柴油的降滤效果,对蜡晶的形态进行了显微观察,利用XRD研究了蜡晶结构.结果表明:CTC-NO对不同柴油降滤效果不同,0#-3柴油降滤效果最好.加爪形大分子后蜡晶形态由规则片状转变为不规则的长形立体状、枝状、球状.XRD结果显示,加CTC-NO后晶粒尺寸变小、蜡晶结构改变.     

Settling of paraffin crystals in cooled middle distillate fuels

The mechanism of action of additives that control the sedimentation of paraffin crystals after their crystallization in model diesel oil has been studied by means of a new experimental approach. The chemical analysis of the crystals and detailed measurements of the sedimentation phenomenon give new insights into this complex process. Thus, the wax antisettling additives used for preventing wax crystal sedimentation adsorb at the surfaces of wax particles and provide them with enhanced colloidal stability. The settling rate is not related to the size of the crystals or the viscosity of the liquid medium, but to the ability of the additives to prevent the aggregation of wax crystals. The reported methodology makes it possible to investigate the fundamental mechanisms, but also to evaluate structure-activity relationships of the various additives used in the petroleum industry.     

Poly-Acrylic Acid Derivatives as Diesel Flow Improver for Paraffin-Based Daqing Diesel

Since the diesel products from paraffin-based Daqing crude oil showed low sensitivity to certain commercial diesel pour point depressant (PPDs) that resulted from the high content of paraffin, certain poly-acrylic acid derivatives (PADE) with -COOR, -COOH, -CONHR, and -COO-NH3 R groups by molecular design on the mechanics of diesel; PPDs were synthesized and evaluated as cold flow improver for Daqing 0# diesel in this paper. The pure PADE was superior to the commercial PPDs and displayed a substantial ability of wax crystals dispersion. There was a synergistic effect among the PADE and T1804 and secondary amine. The synergism clearly improved the low temperature performance of Daqing diesel products and could reduce the cold filter plugging point of 0# diesel by 6-7℃.     

Reversible photocontrol of surface wettability between hydrophilic and superhydrophobic surfaces on an asymmetric diarylethene solid surface

By alternate UV and visible light irradiation, reversible topographical changes were observed on a newly synthesized diarylethene microcrystalline surface between the rough crystalline surface of an open-ring isomer and flat eutectic surfaces. The contact angle changes of a water droplet between 80° and 150° and peak intensities changes of the open-ring isomer in XRD patterns within 2 h of repeating cycle were observed. The results indicated that reversibly photogenerated rod-shaped crystals on the surface were produced based on the lattice of the open-ring isomer crystals in the subphase.     

无定形硅铝载体的酸性对费托蜡加氢裂化反应中柴油选择性的影响

利用逐梯度铵交换处理的方法合成了三个织构性质相似、酸性不同的无定形硅铝载体,并通过XRD、N₂吸附-脱附、NH₃-TPD、Py-FTIR和NMR等手段对载体的物化性质进行了研究。经等体积浸渍负载贵金属Pt,制成加氢裂化催化剂,以费托蜡加氢裂化生产柴油为探针反应,研究了无定形硅铝载体的酸性与柴油选择性之间的构效关系。结果表明,柴油选择性主要与载体的B酸性质有关,受L酸的影响很小;催化剂载体的强B酸含量与柴油选择性成相反关系,载体强B酸的含量越低,柴油选择性越高;催化剂Pt/B-1具有相对最高的柴油选择性,在反应压力7.0 MPa,H₂/wax（volume ratio）=1 000：1,LHSV=1.0 h^-1,温度为370℃的条件下,C₂₂₊转化率为62.52%时,对柴油的选择性达87.12%,具有比文献报道及商业化无定形硅铝载体ASA制备的催化剂Pt/ASA相对更高的活性和柴油选择性。     

出口压减压下非极性薄涂气相色谱柱的特性及应用

以甲基硅油OV－101、210为固定液,研究了出口压减压下薄涂气相色谱 柱的特性,从柱压、柱温、保留值、柱效、柱的稳定性等方面进行了探讨。应用于烷烃及几种农药的分离,效果良好。     

Thermoluminescence properties of natural zoisite mineral under γ-irradiations and high temperature annealing

Natural silicate mineral of zoisite, Ca(2)Al(3)(SiO(4))(Si(2)O(7))O(OH), has been investigated concerning γ-radiation, UV-radiation and high temperature annealing effects on thermoluminescence (TL). X-ray diffraction (XRD) measurement confirmed zoisite structure and X-ray fluorescence (XRF) analysis revealed besides Si, Al and Ca that are the main crystal components, other oxides of Fe, Mg, Cr, Na, K, Sr, Ti, Ba and Mn which are present in more than 0.05 wt%. The TL glow curve of natural sample contains (130-150), (340-370) and (435-475)°C peaks. Their shapes indicated a possibility that they are result of composition of two or more peaks strongly superposed, a fact confirmed by deconvolution method. Once pre-annealed at 600°C for 1h, the shape of the glow curves change and the zoisite acquires high sensitivity. Several peaks between 100 and 400°C appear superposed, and the high temperature peak around 435°C cannot be seen. The ultraviolet radiation, on the other hand, produces one TL peak around 130°C and the second one around 200°C and no more.     

全硅FER沸石上有机吸附物脱附行为的研究

运用热分析技术,研究吸附在体相和表面结构完美的单晶状疏水全硅FER沸石孔道中的有机化合物的脱附行为,测定亲和性指数AT值和负载量。所研究的吸附质为直链烷烃、直链烷基醇、直链烷基胺等,结果显示醇有较低的AT值,而直链烷烃有较高的AT值,胺类有最高的AT值。证明全硅FER沸石骨架对烷基、胺基呈现出强的"亲和性",而对羟基呈现出“憎性”。同时还发现吸附质的链长对脱附性质、AT值也有较大影响。     

A History of Fischer-Tropsch Wax Upgrading at BP—— from Catalyst Screening Studies to Full Scale Demonstration in Alaska

Conversion of Fischer-Tropsch wax into high quality synthetic crude or finished transportation fuels such as premium diesel has been studied over the past 15 years within BP. Catalyst screening and selection was carried out in dedicated micro-reactors and pilot plants, whose designs are critical to the performance selection. Variation in catalyst composition and defining the gas to oil feed ratios with the operating temperature are a few of the parameters studied. Product selection and maximizing diesel yield combined with stability (catalyst life) were the ultimate drivers. The selected catalyst was then tested under commercial conditions in a dedicated 300 barrel per day demonstration plant. The products were also tested in engines to assess their combustion characteristics.     

Rheological Properties of Model and Crude Oil Systems when Wax Precipitate under Quiescent and Flowing Conditions

Wax precipitation and deposition is a recurring challenge in transportation of crude oil, and increased knowledge about the behavior of such systems is necessary. Microscopy and differential scanning calorimetry were used to follow the crystallisation of wax for two model systems. The amount of solid was also determined by the latter method as well. The flow and viscoelastic behavior were investigated around the wax precipitation temperature, and the yield stress was determined both after dynamic and static cooling. Interpretation of the results was carried out in view of crystal growth and microstructure of the wax crystals. The variables that were studied were wax composition, amount of wax and thermal and shear history.