减压渣油胶体稳定性的分子模拟

分子结构特性决定分子间相互作用,进而决定其溶解性能。通过分子模拟研究减压渣油不同结构分子的分子间相互作用、互溶性及由此导致的渣油胶体稳定性。研究表明,芳环数目越多、烷基侧链越短的分子结构内聚能密度越大,溶解度参数越大。在渣油体系中,沥青质、重胶质分子聚集形成胶核,饱和烃、芳香烃、轻胶质分子形成连续相。胶质分子结构影响其胶溶性能,侧链长度适中的胶质分子,其与沥青质、芳香分互溶性好,胶溶性能优异;沥青质的聚集程度随胶质分子含量的增加而降低。芳香分、胶质分子的协同作用使沥青质、饱和烃分子稳定存在于同一体系中,因此渣油胶体稳定性取决于不同分子结构的连续性和配伍性。     

减压渣油微观相结构特性的分子模拟

选用4种模型化合物代表减压渣油四组分(SARA),采用分子动力学模拟了减压渣油微观相结构,发现不同结构分子间相互作用的差异是减压渣油微观非均匀分布的本质原因,并通过电子分布特性分析了不同结构分子间相互作用差异的本质原因。沥青质分子间强相互作用使得沥青质分子自缔合形成聚集体;而多个胶质分子与沥青质分子的强相互作用封闭了沥青质分子自身进一步发生相互作用的活性位;同时,与胶质分子、饱和烃分子具有强相互作用的芳香烃分子将沥青质 胶质分子形成的聚集体分散在由芳香烃 饱和烃分子构成的连续相内,其中芳香烃分子更靠近胶质分子。因此,增加沥青质、饱和烃分子的含量会促进沥青质聚集,降低减压渣油稳定性;增加胶质、芳香烃分子的含量会阻碍沥青质聚集,提高减压渣油稳定性。     

原油减压渣油馏分的油-水界面性质：Ⅷ．减渣馏分分子参数与其模拟乳状液的稳定性

采用相对分子质量测定、元素分析、紫外光谱和红外光谱等手段，确定了大庆减压渣油与伊朗重质减压渣油的分子参数，并考察了两个系列减压渣油馏分的模拟乳状液的稳定性。在此基础上，采用复合变量分析探讨了减压渣油馏分的各分子参数之间的关系，以及这些分子参数与模拟乳状液稳定性的关系。结果表明，减压渣油馏分不同的分子参数对其模拟乳状液稳定性的影响不同，其中馏分的相对分子质量、稠环芳香结构的含量、脂肪烃相对含量、羰基相对含量对模拟乳状液的稳定性影响最明显。一般情况下，馏分的相对分子质量越大、稠环芳香结构和羰基含量越高，则乳状液越稳定。     

原油减压渣油馏分的油-水界面性质ⅩⅢ.减渣馏分分子参数与其模拟乳状液的稳定性

采用相对分子质量测定、元素分析、紫外光谱和红外光谱等手段,确定了大庆减压渣油与伊朗重质减压渣油的分子参数,并考察了两个系列减压渣油馏分的模拟乳状液的稳定性。在此基础上,采用复合变量分析探讨了减压渣油馏分的各分子参数之间的关系,以及这些分子参数与模拟乳状液稳定性的关系。结果表明,减压渣油馏分不同的分子参数对其模拟乳状液稳定性的影响不同,其中馏分的相对分子质量、稠环芳香结构的含量、脂肪烃相对含量、羰基相对含量对模拟乳状液的稳定性影响最明显。一般情况下,馏分的相对分子质量越大、稠环芳香结构和羰基含量越高,则乳状液越稳定。     

大庆—黄岛减压渣油在烃类溶剂中溶解平衡研究

在连续式渣油溶解度测定装置上研究了大庆－黄岛减压渣油（ＤＨＶＲ）与混合Ｃ４溶剂的溶剂平衡规律，结果表明，ＤＨＶＲ与混合Ｃ４溶剂的溶剂平衡模型遵循Ｆｌｏｒｙ－Ｈｕｇｇｉｎｓ方程，由此计算得到了ＤＨＶＲ在１３２～１４２℃的混合Ｃ４溶剂中的溶解参数，外推求得２５℃下的溶解度参数为２４．３ＭＰａ１／２与文献值一致，温度和溶剂组成影响渣油的溶解度，温度升高，溶解度有所降低，提高溶剂的溶解度参数，有利于提高渣     

掺入催化裂化油浆对减压渣油性质的影响

以中国石化茂名分公司减压渣油和催化裂化油浆为丙烷脱沥青的原料,对二者在不同掺入比下的组成和性质进行分析,运用数学回归得出其变化规律,并采用质量分数电导率法以及四组分组成法考察了调合油品胶体稳定性的变化。结果表明：调合油品黏度的变化符合指数函数特性;密度、残炭、元素含量和族组成的变化符合一次函数特性;调合油品胶体体系的稳定性下降。综合调合油品的性质与稳定性等情况,催化裂化油浆掺入比控制在30%以下比较合适。     

减压渣油高温模拟蒸馏误差分析及对策

以CS2(空白试样)为气相色谱仪的清洗液,C_5~C_(120)正构烷烃为校正试样,沸程为354~541℃的参考试样为外标试样,减压渣油为样品,在气相色谱高温模拟蒸馏仪中,通过对ASTM D 7169原理的剖析,以及对减压渣油样品模拟蒸馏实验的分析,确定了引起减压渣油高温模拟蒸馏误差的主要原因。结果表明:在对空白试样分析时,残留样品引起基线5×10-12A以上的波动,即可使馏出温度产生3℃以上的偏差;正构烷烃保留时间的漂移直接影响馏程数据的准确性,因此,需每14 d分析1次沸点校正样品;参考试样进样量的准确性、进样垫的气密性和称量的准确性均是导致分析结果出现误差的主要原因。     

加氢转化过程中蜡油对减压渣油胶体稳定性的影响

以沙特重质减压渣油(SZ)与减压蜡油(质量比3∶1)进行混合后的油样为原料,介绍了掺炼减压蜡油前后SZ在STRONG沸腾床中试装置上加氢转化情况,并利用斑点试验、胶体不稳定性参数及平均结构参数对油样的胶体稳定性及其影响因素进行了考察。表明斑点试验可直观地反映出生成油的胶体稳定性变化情况。不稳定性参数表明,随着加氢转化率增加,两种原料加氢生成油的稳定性呈先增大后减小的变化趋势,相同工艺条件下混合油样加氢生成油的稳定性优于SZ;利用改进B-L法计算不同油样的平均分子结构参数,加氢转化后两油样的芳碳率(fA)与缩合度(CI)均有明显降低,混合油样生成油的fA与CI较SZ降低约5%和0.04;在相同的转化率下,采用低温长时间操作更有利于维持体系的稳定性。     

烷基水杨酸盐的胶体结构与其稳定性关系研究

介绍了国内外几种不同碱值烷基水杨酸钙盐金属清净剂的性能,考察了不同碱值烷基水杨酸盐产品的胶体粒子结构及粒子分布状态、胶体粒子的稳定性以及与高碱值磺酸钙的复合效果,结果表明,添加剂中胶体粒子的结构是影响其胶体稳定性的重要因素,胶体粒子的粒径越小,粒子分散越均匀,其胶体稳定性越好,兰炼已全面生产的改性中碱值产品及高碱值产品,与磺酸盐相容性良好,混兑后无沉淀生成。     

糠醛与芳烃分子间作用力的本质研究

采用分子动力学和量子力学相结合的方法,对糠醛精制润滑油基础油工艺中糠醛与不同环数芳香烃的相互作用进行了计算.结果表明:糠醛与芳香烃的相互作用能和静电作用能均随着芳环数目的增多而增大,这是由于多环芳烃的离域π电子更容易受到外部电场的诱导,从而产生诱导偶极矩;糠醛分子在与芳烃形成二聚体时,单体分子间有电子转移现象;溶剂分子...     

True Boiling Point Extended Curve of Vacuum Residue Through Molecular Distillation

Molecular distillation is a separation process that explores high vacuum, operation at reduced temperatures, and low exposition of the material at the operating temperature. The term vacuum residue (heavy petroleum fractions) refers to the bottom of the vacuum distillation, which has an atmospheric equivalent temperature (AET) above 540°C. For the assay of the properties of petroleum and petroleum products, the use of the true boiling point (TBP) distillation analysis is accepted as a common practice; however, for heavy petroleum fractions, some difficulties appear for determination of TBP of these petroleum fractions. The objective of this work is to develop a new and a more appropriated method to extend the TBP curve to use it for characterizing vacuum residue of heavy petroleum. The falling film molecular distillator was used. The results showed that it is possible to extend the TBP curve through molecular distillation process with very good precision.     

Effect of Different Aromatic Fractions on Colloidal Property of Tahe Atmospheric Residue

Different amounts of FCC slurry oil and HVGO were added to Tahe atmospheric residue respectively.The colloidal stability and asphaltene agglomeration of atmospheric residue and mixed oils were characterized by means of the mass fraction normalized conductivity and the small-angle X-ray scattering technology(SAXS).The results indicated that the stability of Tahe atmospheric residue decreased with an increasing amount of these oil fractions.It was found that the decline of the colloidal stability was attributed to the component polarity difference between oil fractions and the atmospheric residue.Though the aromaticity of FCC slurry oil was higher than that of HVGO,the polarity of aromatics and resins of FCC slurry oil was lower than those of HVGO.So the degree of the colloidal stability was more seriously destroyed by FCC slurry oil.The dispersion of asphaltenes in Tahe atmospheric residue was changed by adding FCC slurry oil and HVGO.The particle size of asphaltenes increased along with the decline of the colloidal stability.     

Investigation on the Chemical Composition and Structure of Daqing Vacuum Residue Narrow Fractions

The Daqing vacuum residue (DQVR) was separated into 14 narrow fractions by Supercritical Fluid Extraction and Fractionation (SFEF). The contents of element, metal, molecular weight, density, carbon residue of the narrow fractions were measured. Structure parameters were calculated by Densimetric method. Characterization index K_h, and boiling point of narrow fractions were proposed to characterize the fractions and predict their properties. On the basis of the analysis results, the knowledge of Daqing vacuum residue was extended. There will be a big potential use for the DQVR as catalytic stocks.     

Investigation on the Chemical Composition and Structure of Daqing Vacuum Residue Narrow Fractions

Abstract

The Daqing vacuum residue (DQVR) was separated into 14 narrow fractions by Supercritical Fluid Extraction and Fractionation (SFEF). The contents of element, metal, molecular weight, density, carbon residue of the narrow fractions were measured. Structure parameters were calculated by Densimetric method. Characterization index K _h , and boiling point of narrow fractions were proposed to characterize the fractions and predict their properties. On the basis of the analysis results, the knowledge of Daqing vacuum residue was extended. There will be a big potential use for the DQVR as catalytic stocks.     

分子动力学模拟计算超临界CO2的溶解度参数

采用分子动力学模拟方法,计算了超临界CO2和超临界CO2-乙醇体系的溶解度参数,并分析了体系内粒子间距离的径向分布函数。结果表明,超临界CO2的溶解度参数随温度的升高而减小,随压力的增大而增大,且随体系密度的增大而线性增大;添加乙醇可明显提高超临界CO2的溶解度参数,且随着乙醇浓度的增加,在相同条件下的溶解度参数也增大。乙醇分子可与CO2分子形成分子间氢键而提高CO2的极性,从而提高体系的溶解度参数;超临界CO2-乙醇体系中,分子间,特别是乙醇分子间存在聚集现象。当体系压力较低时,增大压力,可大幅度减弱乙醇分子间的聚集程度,使体系的溶解度参数迅速增大;但继续增大压力到一定程度时,乙醇分子间的聚集程度达到定值,即乙醇已均匀分散在CO2中,溶解度参数随压力的变化趋于平缓。     

超声波处理对渣油加氢反应过程胶体性能的影响

超声波处理改变了渣油饱和分、芳香分、胶质、沥青质(SARA)的含量、结构和分布状态,使渣油胶体稳定性得到改善。沥青质的含量、结构和分布状态对渣油胶体稳定性有重要影响。超声波处理改变了沥青质的结构,减少了渣油中沥青质的含量,大幅增加了溶胶能力强的胶质的含量,改善了沥青质的分散状态,使渣油胶体稳定性增加。超声波处理后渣油四组分理化性质的变化改善了渣油品质,提高了渣油和沥青质的反应性能,加氢反应深度增加,产物分布改善,但加氢残渣油的胶体稳定性降低。超声波处理对渣油及其加氢残渣油的胶体稳定性具有重要影响。     

Evaluation of Atmospheric and Vacuum Residues Using Molecular Distillation and Optimization

The term atmospheric residue describes the material at the bottom of the atmospheric distillation tower having a lower boiling point limit of about 340°C; the term vacuum residue (heavy petroleum fractions) refers to the bottom of the vacuum distillation, which has an atmospheric equivalent boiling point (AEBP) above 540°C. In this work, the objective is to evaluate the behavior of different kinds of Brazilian atmospheric and vacuum residues using molecular distillation. The Falling Film Molecular Distillator was used. For the results obtained through this process, a significant range of temperature can be explored avoiding the thermal decomposition of the material. So these results are very important to the refinery decisions and improvements. The Experimental Factorial Design results showed that the temperature has more influence on the process than the feed flow rate, when a higher percentage of distillate is required.