Insights into the Structure-Performance Relationship and Viscosity Reduction Performance of Recyclable Magnetic Fe/Zeolite for Crude Oil Aquathermolysis.

Elucidating the structure-performance relationship of zeolites and their synergy with metals for the catalytic aquathermolysis of crude oil is crucial for designing efficient catalysts. Herein, the structure-performance relationship between the magnetic Fe-loaded zeolite's physicochemical properties and aquathermolysis performance is mainly explored. First, the catalytic aquathermolysis performance of various porous materials (Y, ß, MCM-41, and ZSM-5 zeolites) was probed to investigate the effect of different topological structures on the viscosity reduction of heavy oil. Results showed that ZSM-5 has a favorable pore structure and acidity, and its viscosity reduction performance is 1.7-4.1 times those of other zeolites; therefore, it is more suitable as a carrier for aquathermolysis to reduce viscosity. Then, Fe substance (such as Fe2O3 and Fe3O4) was loaded onto the ZSM-5 support. It was found that Fe3O4/ZSM-5 had better performance compared with pure ZSM-5 and Fe2O3/ZSM-5, which could reduce the viscosity of heavy oil by 20.3%. Importantly, the Fe3O4/ZSM-5 catalyst is easily separated from crude oil due to its magnetism, hence it has the potential to be recycled and reused. In addition, the potential structure-performance relationship was systematically studied by X-ray diffraction (XRD), elemental analysis (EL), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FT-IR). As a result, it was considered that Fe3O4/ZSM-5 broke C-S bonds and reduced the heavy components (resin and asphaltene) of crude oil. This study has a certain guiding significance for developing heterogeneous magnetic hydrothermal viscosity reduction catalysts.

Method for Judging the Stability of Asphaltenes in Crude Oil.

The colloidal instability index (CII) has been widely used for testing the stability of asphaltenes as a classical method. In this study, five oil samples were tested by the CII method; the results obtained greatly differ from the real field results. In our investigation, we combined the Turbiscan LAB stability analyzer and saturate, aromatic, resin, and asphaltene (SARA) analysis to further investigate the asphaltene stability by heptane titration. The results revealed that there exists a threshold volume ratio before the asphaltenes destabilize. The stability of crude oil is related to the saturation solubility of asphaltenes. By testing the CII value of the crude oil in its current state and the CII value of the dissolved asphaltenes in its saturated state, we were able to propose a new way to judge the oil stability.