Upgradation of Heavy Crude Oil Via Hydrodynamic Cavitation Through Variations in Asphaltenes

In this work,Saudi heavy crude oil(SHCO)was upgraded by the hydrodynamic cavitation technique.The collapse of cavitation bubbles instantly produces extreme conditions such as high temperature,pressure,and jet flow and strong shear forces,which can play a significant role in the upgradation process.The results revealed that the viscosity and Conradson carbon residue of SHCO decreased from 13.61 to 7.22 mm^(2)/s and from 7.16%to 6.48%,respectively.True boiling point distillation findings showed that the vacuum residue(VR)decreased by 1%.Atmospheric-pressure photoionization Fourier-transform ion cyclotron resonance mass spectrometry,X-ray diffraction,dynamic light scattering,Fourier-transform infrared spectroscopy,and scanning electron microscopy were employed to characterize the molecular composition,crystalline structure,asphaltene aggregate particle size distribution,functional groups,and morphology,respectively,to understand the effects of hydrodynamic cavitation on asphaltenes.The obtained results demonstrate that hydrodynamic cavitation upgradation reduced the interaction forces between the asphaltene molecules,weakening the crystalline structure of the asphaltene aggregates,reducing the degree of association of the aromatic compounds in SHCO and asphaltenes,and decreasing the average particle size.The delayed coking properties of the VR were further investigated,and the cavitation treatment was found to decrease the coke yield by 1.85%and increase the liquid and gas yields by 1.52%and 0.33%,respectively.Hence,hydrodynamic cavitation can effectively enhance the processing performance of crude oil by improving the properties and structural characteristics of asphaltenes.

多级孔分子筛的制备与催化应用

分子筛研究的热点问题之一是如何减小微孔扩散阻力对传质带来的不利影响,以提高催化剂的利用效率。通过引入介孔,实现多级孔分子筛材料的设计是解决上述问题的一种有效方法。本文介绍了多级孔分子筛材料提高反应扩散效率的理论依据以及国内外多级孔分子筛材料制备方面的研究进展。主要包含"破坏性"方法(destructive methods)和"建设性"方法(constructive methods)的原理,从水热稳定性、酸性、操作性以及可放大性分析了各种合成方法的优势和不足。本文还介绍了多级孔分子筛在催化反应中的若干应用实例,重点介绍了多级孔材料在催化裂化和加氢反应中的应用进展,表明多级孔分子筛可以提高选择性以及转化率。开发适宜酸性以及水热稳定性的微孔-介孔分子筛,同时兼顾低成本、低污染以及易操作性的合成技术是将来研究的重点,同时应建立多级孔分子筛催化性能与结构的关系,加深对多级孔分子筛的认识。