Molecular Reconstruction Of Crude Oil

Molecular reconstruction techniques are methods that allow creating mixtures of molecules from partial analytical data. The content of carbon and hydrogen are more than 95% in most crude oil, and the small amount of non-hydrocarbon elements have little influence on the process of atmospheric-vacuum crude oil distillation, so it is acceptable to do not consider the small amount of non-hydrocarbon elements in the process of crude oil distillation simulation. In order to simplify the calculation process appropriately and have little impact on the accuracy of the results, the form of hydrocarbon molecules in the crude oil are only considered and the non-hydrocarbon molecules which contain other elements are dealed with as hydrocarbon molecules in the paper. First properties estimation equations suitable for hydrocarbon molecules in crude oil are selected through verification calculation in a large scale. Next, the virtual elements of crude oil are obtained through Monte Carlo random sampling. The properties of the virtual molecular mixture are obtained through the mixing rules of various properties of hydrocarbon molecules, and the objective function is obtained by comparing the calculation data with the calibration data of crude oil. Then the simulated annealing algorithm is selected to optimize the objective function to achieve the required optimization goals, and the initial crude oil molecular contents are established. The content of the various elements are adjusted on the basis of the yield of the narrow fractions in true boiling point distillation of crude oil. Last the molecular reconstruction of crude oil is completed. The results show that molecular reconstruction method has good adaptability for different types of crude oil. Molecular structure properties and the distribution of molecules in crude oil can be reflected by the generation molecular contents.