Molecular Dynamics Study Of The Composition And The Dissolution Theory Of Heavy Oil

The research about composition and dissolution theory of Heavy oil has made greatprogress. Because the limitation of experimental conditions that the microscopic studies ofsolubility have not obtained the breakthrough. All that severely restricted the use of Heavy oil.We simulate the component of Heavy oil with the theories of MD and F-H in MS. The papershould complete the study of the microscopic mechanism and make the guidance for theinhibition of coagulation.Firstly, we select the two types of Heavy oil as the research object (THAR and SZAR).We build a major component of heavy oil model in the MS software. In order to determineappropriate calculation parameters, we simulate the THAR and SZAR component density. Weobtained the reference matches the height data and the relation errors are3.0%. Through thefirst simulation, we determine the feasibility and accuracy. We build a foundation for thecalculation by the study about the unit of Heavy oil.Secondly, we studied the mixture properties of the asphalt in the five different solventswith the extension F-H and the MD. After simulation, we study the binding energy, theinteraction parameter, free energy and so on. We know about the asphalt coagulation abilityof depolymerization. The binding energy and interaction parameter show that the solventinsoluble asphaltene within the scope of100-600K. On the contrary, the binding energy andinteraction is negative. The simulation calculation confirmed that the raising temperaturehas the positive effect for the solution of heavy oil, but the temperature should be controled inthe reasonable scope. If we want get a good depolymerization and the better activity of thecatalyst, the temperature should be at about600k.At last, we respectively study the energy and the configuration with MS. In energyaspects: we research the asphalt aggregate under the condition in the different temperature, different solvents. After that, we analyzed the interaction energy, solubility parameters. Weknow the role of energy and π-π in coagulation. In configuration aspects, we simulated themolecules of RDF, the bending of the layered structure, the change of molecular spacing andso on. The result shows that higher temperature can make the structure more stretch. Theextension of branched can reduce the happening of coagulation. When we add aromaticsolvent, the space between asphaltene molecules will increase. The aromatic solvent destroysthe π-π bond of asphaltene molecules. These simulation experiments have found thequantitative data of the asphalt coagulation. We perfected the dissolving mechanism of heavyoil and offered the theoretical guidance for the effective use of Heavy oil.