Insights into the mechanism during viscosity reduction process of heavy oil through molecule simulation

Preparation of Fe‐based magnetic‐core‐supported Co and Ni catalyst: application in viscosity reduction of heavy oil hydrocracking

“…As shown in Table 3, the viscosity reduction rate of Fe‐Fe 2 O 3 @SiO 2 @Al 2 O 3 @CoNi product oil is 99.8% (50 °C), and that of Fe 3 O 4 @SiO 2 @Al 2 O 3 @CoNi‐I product oil is 88.5% (50 °C). Among the components of heavy oil, asphaltene is usually considered the key component that causes high viscosity of heavy oil, as it can form aggregation through polar groups and alkyl chains 39 . The main differences between Fe 3 O 4 @SiO 2 @Al 2 O 3 @CoNi‐I and Fe‐Fe 2 O 3 @SiO 2 @Al 2 O 3 @CoNi is the type of magnetic nucleus.…”

“…Among the components of heavy oil, asphaltene is usually considered the key component that causes high viscosity of heavy oil, as it can form aggregation through polar groups and alkyl chains. 39 The main differences between Fe 3 O 4 @SiO 2 @Al 2 O 3 @CoNi-I and Fe-Fe 2 O 3 @SiO 2 @Al 2 O 3 @CoNi is the type of magnetic nucleus. Magnetic nanochain structures are composed of several magnetic nanoparticles arranged in a specific direction in a regular manner.…”

Pathway of Oil-Soluble Additives to Reduce Heavy Crude Oil Viscosity Depends on the Molecular Characteristics of Asphaltene

“…MD simulations were performed using the GROMACS 2019.6 package, employing the CHARMM36 force field, which has proven its reasonability and validity and been widely used in the study of heavy oil systems. ,,, The particle-mesh Ewald (PME) , method was employed to perform Coulomb potential calculations, while hydrogen bond lengths were constrained using the LINCS algorithm . Prior to simulations, all molecules underwent Gaussian 09 conformational optimization at the B3LYP/6-311G** level, ,, with atomic charges obtained through the Multiwfn 3.7 package using the restrained electrostatic potential (RESP) fitting approach . The time step for MD simulations was 1 fs, and the periodic boundary conditions were applied in all directions of the simulated box.…”

“…Apart from system A and system B, a kind of oil-soluble VR molecule (Figure 1 and Section S1 in Supporting Information) with a 7 % mass fraction of SARA molecules was added, generating system A-VR and system B-VR. The VR molecule contains a polar head and a nonpolar tail; they are chemical blocks derived from the work of Xu et al 24 The fraction of SARA components was referenced from the work of Xu et al 24 Because of the limitations of computational simulations on time and length scales, molecule models are always extremely simplified. However, they are useful and reasonable; they contain physics that awaits our clarification.…”

“…To provide insights into microscopic interactions between different heavy oil components and VRs, which are difficult to obtain from experiments, computational methods including quantum mechanics (QM) calculations and molecular dynamics (MD) simulations have been employed to explore dynamics and thermodynamics in heavy oil systems. Based on this, the molecular mechanisms of water-soluble VRs ,, and oil-soluble VRs , have been studied. In the MD simulation work of Xu et al, it was revealed that the oil-soluble VRs induce the transformation from face-to-face stacking of asphaltenes to face-to-face stacking of asphaltenes and resins, which was considered as the mechanism of reducing heavy oil viscosity.…”