双亲分子头部官能团对石油沥青质胶团分散性的影响Ⅱ.石油沥青质胶团形状、溶剂化程度与相互作用

为理解双亲分子对石油沥青质甲苯溶液巾沥青质胶团形状、溶剂化程度以及颗粒间相互作用的影响,测定了其甲苯溶液的黏度,采用Pals-Rhodes方程、Eiler方程、Kuhn-Kuhn方程和Leighton-Acrivos方程关联了黏度与体积分数之间的关系.由Pals-Rhodes方程得到的形状参数α和溶剂化参数K表明.在沥青质甲苯溶液中沥青质胶用为球形.添加双亲分子后其溶剂化程度增加,但其形状仍为球形.由Eiler方程分析表明,沥青质甲苯溶液添加双亲分子后,沥青质最大堆积体积分数ψ_m增加,说明沥青质胶团的分散度增加.由Kuhn-Kuhn方程计算所得沥青质甲苯溶液中沥青质颗粒的形状因子严重偏离球形,因未考虑溶剂化效应和颗粒间的相互作用,故与Pals-Rhodes方程得到的结果差别较大.由Leighton-Acrivos方程得到的相互作用系数表明,沥青质甲苯溶液添加双亲分子后,沥青质胶团之间的相互作用程度增加.     

双亲分子头部官能团对石油沥青质胶团分散性的影响Ⅰ.石油沥青质胶团尺寸

为认识含有不同头部官能团的双亲分子对沥青质胶团分散性的影响,测定了添加十二烷基苯磺酸(DBSA)、十二烷基苯酚(DP)和十二醇的沥青质甲苯溶液的黏度变化规律,通过线性拟合得到其特性黏度[η],进而计算得到无限稀释情况下沥青质胶团直径.同时,对比了添加双亲分子前后沥青质甲苯溶液的比浓黏度随沥青质浓度的增加速率和胶团直径的变化.结果表明,酸性较强的十二烷基苯磺酸易于在沥青质表面吸附,在高浓度时,甚至可以明显增加沥青质胶团的直径.十二烷基苯酚吸附量较小,不能明显改变沥青质胶团的大小,而十二醇较难在沥青质表面吸附,对沥青质溶液的黏度几乎没有影响.由此可以初步推断,双亲分子头部官能团的酸性越强,其与沥青质的作用越强,在沥青质表面吸附的越多,其抑制沥青质聚并的能力越强.     

双亲分子头部官能团对石油沥青质胶团分散性的影响

为认识含有不同头部官能团的双亲分子对沥青质胶团分散性的影响,测定了添加十二烷基苯磺酸(DBSA) 、十二烷基苯酚(DP)和十二醇的沥青质甲苯溶液的黏度变化规律,通过线性拟合得到其特性粘度,进而计算得到无限稀释情况下沥青质胶团直径。对比添加双亲分子前后,比浓黏度随浓度的增加速度和胶团直径的变化都表明：双亲分子头部官能团酸性越强,其与沥青质的作用越强,在沥青质表面吸附的越多。酸性较强的十二烷基苯磺酸在沥青质表面能形成多层吸附或者发生聚集,十二烷基苯酚只能形成单层吸附,而十二醇则对沥青质溶液的黏度几乎没有影响,可能没有发生吸附。     

双亲分子与石油沥青质作用的zeta电位

 为认识双亲分子与沥青质作用的机理,采用电泳光散射法测定了添加双亲分子前后沥青质溶液和渣油溶液zeta电位的变化,并由此计算了不同条件下胶团的电性斥力位能。实验结果表明,不同沥青质在甲苯溶液中的zeta电位的大小和电荷的正负性并不相同。zeta电位与沥青质的表面官能团组成有关外,双亲分子A在沥青质表面的吸附会改变沥青质胶团的zeta电位。可以推断,沥青质胶团在有机溶剂中所带的电荷来自电荷转移作用。双亲分子对不同渣油热反应的影响并不相同,说明沥青质胶团zeta电位与双亲分子端基官能团之间需要一定的匹配性。胶团间电性斥力位能不是影响沥青质胶体稳定性的主要因素。     

双亲分子稳定辽河沥青质的作用及其机理

 为认识双亲分子化合物对沥青质的稳定作用及稳定机理,采用X射线光电子能谱（XPS）分析了辽河沥青质颗粒表面杂原子官能团的类型和含量;采用紫外－可见光谱(UV-Vis)测定添加双亲分子前后沥青质甲苯－正庚溶液中沥青质浓度的变化,进而分析了不同双亲分子化合物对辽河沥青质的分散稳定作用;采用红外光谱(FT-IR)分析初步探讨了十二烷基苯磺酸（DBSA）对沥青质分散稳定作用的机理。结果表明,沥青质颗粒表面含氮官能团主要为碱性的吡啶氮官能团和弱碱性的吡咯氮官能团,含氧官能团主要为碳氧单键和碳氧双键结构,表面杂原子官能团的数量虽然较少,但为沥青质与双亲分子作用的关键因素;双亲分子头部官能团和沥青质颗粒表面杂原子之间的酸碱作用越强,其分散稳定沥青质的能力越强;DBSA通过其磺酸基官能团与沥青质颗粒表面的羟基和氨基形成分子间氢键而吸附在沥青质上。     

基于特性黏度法计算沥青质胶团直径和溶剂化效应——分散体系活化状态表征

在委内瑞拉常压渣油中添加不同比例十八醇,考察十八醇对强化减压蒸馏效果的影响。结果表明,十八醇具有良好强化效果,最大蜡油净增收率为4.01%。测定渣油(沥青质)-甲苯溶液的黏度,根据Einstein黏度定律和Pals-Rhodes方程,计算得到了沥青质胶团直径D和溶剂化参数K,结果表明,特性黏度法测得的沥青质尺寸为沥青质胶核外吸附-溶剂化层的直径,其数值受溶剂化效应的影响,测定渣油-甲苯溶液黏度可以表征渣油体系中沥青质胶团尺寸。对于添加了十八醇的渣油体系,其沥青质胶团直径减小、溶剂化效应降低,变化趋势与减压蜡油净增收率有良好的对应关系,可以采用特性黏度法计算沥青质胶团直径和溶剂化效应,来预测石油分散体系的活化状态。     

石油沥青质的热解化学

石油沥青质热分解之所以引起人们的兴趣,是由于沥青质在石油加工过程中易生成高产率的焦炭,并使催化剂失活。总的说来是认为,生焦化学包括热不稳定键的热解生成活性物质,然后进一步反应生成焦炭。本文的数据表明:初次反应生成分子量较低的产物,这些分子中氮的存在促进了键的断裂。其它诸如环烷系的芳构化与芳环系的最终缩聚等反应将导致焦炭的生成。一个重要的新发现是焦炭的生成并不经由直接缩合反应,而是通过初次反应生成分子量较低的产物,它们的芳香度高,并含有原始沥青质中大部分的氮(氧或硫)。     

石油沥青质的化学和物理─Ⅰ石油沥青质的定义和分离

石油沥青质是最重要的石油组分之一，它在石油的勘探、开发、储运、加工及重质石油产品利用方面有着重要作用．本文论述了石油沥青质的含义及分布沥青质的各种方法，详细讨论了使用溶剂分离沥青质的理论基础和各种影响因素。     

石油沥青质的化学和物理：Ⅳ.石油沥青质溶液的胶体化学

本文从胶体化学的角度讨论了石油青质的性质，评述了自１９２４年以来提出的各种沥青胶体模型，探讨了石油胶粒的形状和尺寸，形成机制以及沥青质粒子聚集的动力学行为。     

EFFECT OF ASPHALTENE AND RESINS ON THE STABILITY OF WATER-IN-WAXY OIL EMULSIONS

ABSTRACT

Asphaltene, resins and paraffin waxes, their mutual interactions and their influence on the stability of water-in-oil emulsions have been studied. 20 wt % paraffin wax dissolved in decalin was used to model the waxy crude oil. Asphaltene and resins separated from a crude oil were used to stabilize the water-in-oil emulsions. Synthetic formation water was utilized as the aqueous phase of the emulsion. The emulsion stability increased with increasing the concentration of asphaltene with a subsequent decrease in the average particle size distribution of the emulsion. Resins alone are not capable of stabilizing the emulsion, however, in the presence of asphaltene they form very stable emulsions. Dynamic viscosity and pour point measurements provided evidence for resins-paraffin waxes interactions. Asphaltene in the form of solid aggregates form suitable nuclei for the wax crystallites to build over with a mechanism similar to that of paraffin wax crystal-modifiers. As asphaltene are polar in nature they are derived at the oil/water interface which was proved by the ability of asphaltene to reduce oil/water interfacial tension. Consequently, nucleation of the wax crystallites by asphaltene and resins at the interface will add to the thickness of the oil-water interfacial film and hence increase the stability of the emulsion.     

EFFECT OF ASPHALTENE AND RESINS ON THE STABILITY OF WATER-IN-WAXY OIL EMULSIONS

Asphaltene, resins and paraffin waxes, their mutual interactions and their influence on the stability of water-in-oil emulsions have been studied. 20 wt % paraffin wax dissolved in decalin was used to model the waxy crude oil. Asphaltene and resins separated from a crude oil were used to stabilize the water-in-oil emulsions. Synthetic formation water was utilized as the aqueous phase of the emulsion. The emulsion stability increased with increasing the concentration of asphaltene with a subsequent decrease in the average particle size distribution of the emulsion. Resins alone are not capable of stabilizing the emulsion, however, in the presence of asphaltene they form very stable emulsions. Dynamic viscosity and pour point measurements provided evidence for resins-paraffin waxes interactions. Asphaltene in the form of solid aggregates form suitable nuclei for the wax crystallites to build over with a mechanism similar to that of paraffin wax crystal-modifiers. As asphaltene are polar in nature they are derived at the oil/water interface which was proved by the ability of asphaltene to reduce oil/water interfacial tension. Consequently, nucleation of the wax crystallites by asphaltene and resins at the interface will add to the thickness of the oil-water interfacial film and hence increase the stability of the emulsion.     

催化剂粒径分布对催化裂化产物选择性的影响

以青岛加氢蜡油为原料,在小型固定流化床装置上通过改变剂油比,研究了催化裂化催化剂粒径分布对裂化产品选择性的影响。研究结果表明,随着剂油比的增加,四种不同粒径分布的催化剂的转化率逐渐增加;粒径在40~80 μm的催化剂具有较优的干气、焦炭和汽油选择性;粒径小于40 μm的催化剂尽管微反活性最高,但重油转化能力最差;随着转化率的增加,汽油中正构烷烃和芳香烃的含量逐渐增加,烯烃和环烷烃的含量逐渐减少。     

晶种对合成小晶粒SAPO-34分子筛的影响

以较廉价的三乙胺为模板剂,考察晶种的种类、添加环境、添加量及晶粒大小对其辅助合成SAPO-34分子筛的影响,并对晶种诱导机理进行探究。结果表明：含SAPO-5杂晶的晶种会诱导体系产生相同AFI结构的SAPO-5分子筛,但采用磷酸预处理20 h后,可制备出纯净的SAPO-34分子筛;在辅助合成中,晶种硅铝比对合成产品的收率和粒径影响明显,无论添加在酸性还是弱碱性的晶化液中,高投料硅铝比下制备的晶种均更有利于提高产品收率、降低产品平均粒径,其中酸性体系对晶种的部分刻蚀作用可提供更多表面,使晶种的诱导效应更强;在晶种添加量(占晶化液的质量分数)为0～0.5%时,随着高硅铝比晶种添加量的增大,产品收率提高,D(50)降低,且变化尤为明显,当高硅铝比晶种添加量大于1%后,晶种添加量对产品收率和D(50)的影响趋于平缓。此外,晶种辅助合成的小晶粒产品可继续用作晶种起诱导作用,且以之合成产品的收率、平均粒径、元素组成、形貌、孔结构与采用初始大颗粒晶种辅助合成的产品相近,为稳定、连续合成粒径可控的小晶粒分子筛奠定了基础。     

RHEOLOGY, PARTICLE SIZE DISTRIBUTION, AND ASPHALTENE DEPOSITION OF VISCOUS ASPHALTIC CRUDE OIL-IN-WATER EMULSIONS FOR PIPELINE TRANSPORTATION

The rheology of an asphaltic heavy crude oil-in-water emulsions stabilized by an anionic (RN) and a nonionic (TEP) surfactants individually or in a mixture has been studied. The investigated crude oil has a non-Newtonian, time dependent, shear thickening, rheopectic behavior with a relatively high yield stress. The relatively high yield stress of this crude oil is attributed to the presence of a relatively high asphaltene and resins content. The viscosity ofhe crude oil decreases when it is emulsified with synthetic formation water in the form of an oil-in-water type of emulsion using a nonionic or an anionic surfactant. It has been found that, the maximum oil content required for forming an oil-in-water emulsion of acceptable viscosity is the 60% oil-containing emulsion. However, the 70% oil-containing emulsion is not an oil-in-water type of emulsion but it is rather a complicated mixture of oil-in-water-in-oil type of emulsion. The presence of the anionic and the nonionic surfactants together has a synergistic effect in decreasing the total surfactant concentration required to stabilize the emulsion and to form low viscosity emulsion. It has been emphasized that the nonionic surfactant has a positive contribution in forming emulsions with low viscosity. Meanwhile, the anionic surfactant contributes in stabilizing the emulsion at lower concentrations. Flocculation point measurements showed that the added surfactants caused no sign of asphaltene deposition. This implies that it is safe to use the investigated surfactants in forming oil-in-water emulsion for viscous asphaltic crude oils without any fear of asphaltene deposition.     

RHEOLOGY,PARTICLE SIZE DISTRIBUTION,AND ASPHALTENE DEPOSITION OF VISCOUS ASPHALTIC CRUDE OIL-IN-WATER EMULSIONS FOR PIPELINE TRANSPORTATION

The rheology of an asphaltic heavy crude oil-in-water emulsions stabilized by an anionic (RN) and a nonionic (TEP) surfactants individually or in a mixture has been studied. The investigated crude oil has a non-Newtonian, time dependent, shear thickening, rheopectic behavior with a relatively high yield stress. The relatively high yield stress of this crude oil is attributed to the presence of a relatively high asphaltene and resins content. The viscosity ofhe crude oil decreases when it is emulsified with synthetic formation water in the form of an oil-in-water type of emulsion using a nonionic or an anionic surfactant. It has been found that, the maximum oil content required for forming an oil-in-water emulsion of acceptable viscosity is the 60% oil-containing emulsion. However, the 70% oil-containing emulsion is not an oil-in-water type of emulsion but it is rather a complicated mixture of oil-in-water-in-oil type of emulsion. The presence of the anionic and the nonionic surfactants together has a synergistic effect in decreasing the total surfactant concentration required to stabilize the emulsion and to form low viscosity emulsion. It has been emphasized that the nonionic surfactant has a positive contribution in forming emulsions with low viscosity. Meanwhile, the anionic surfactant contributes in stabilizing the emulsion at lower concentrations. Flocculation point measurements showed that the added surfactants caused no sign of asphaltene deposition. This implies that it is safe to use the investigated surfactants in forming oil-in-water emulsion for viscous asphaltic crude oils without any fear of asphaltene deposition.     

粘度指数改进剂对油品性能的影响

介绍了几种粘度指数改进剂的主要性能对比，包括增粘性、剪切稳定性、热氧化安定性、低温性能、高温性能及与降凝剂的配伍性等，为粘度指数改进剂的选择提供参考。     

石灰石粒径对循环流化床锅炉运行的影响

分析石灰石粒径对循环流化床锅炉及石灰石系统运行所造成的影响,说明只有选择合理的石灰石粒径分布,并严格控制,才能保证锅炉及石灰石系统安全稳定运行,也才能提高脱硫效率,降低石灰石消耗量。