| Diesel hydrotreating can improve the quality of diesel and is one of the common processing methods in refineries.Modeling the diesel hydrotreating can guide the process and maximize the economics of the refinery.And the dissolution of hydrogen in liquid diesel is a prerequisite for hydrotreating.Therefore,this paper proposes a method for building a diesel hydrogen solubility model based on the modified Henry equation,and applies this to the molecular transformation process modeling of diesel fixed-bed hydrotreating.In this paper,the experimental data of hydrogen solubility of typical hydrocarbon compounds in diesel are used to construct the correlation between Henry coefficient and temperature and liquid hydrogen concentration.The relationship between the bulk properties and the structure parameters of the hydrocarbon compounds and the Henry coefficient parameters was found,and two Henry coefficient parameter correlation methods were developed to obtain the modified Henry equation.The equation is applied to the mixed system to predict the solubility of hydrogen,which proves that the method can be applied to mixed systems.Therefore,based on molecular management technology,this paper combines the molecular-level hydrogen solubility model with the molecularlevel composition model.The bulk properties of the Henry coefficient method and the average structure parameters of the Henry coefficient method were used to calculate the hydrogen solubility of diesel.The results were compared with the experimental results.It was found that the calculation results based on the average structure parameter of diesel correlated with the Henry coefficient parameters were good due to the transmission error.Therefore,the average structural parameters of diesel can be obtained by constructing a molecular-level composition model of diesel,thereby predicting the hydrogen solubility of diesel.After that,the molecular transformation of diesel fixed bed hydrotreating is modeled.First,a diesel molecular composition model is constructed to obtain the characteristic molecular information of diesel.According to the reaction mechanism,16 hydrotreating reaction rules were formulated and a diesel hydrotreating reaction network was generated.According to the reaction mechanism of diesel hydrotreating,a suitable kinetic equation is selected to construct a molecular-level reaction kinetic model.For the hydrotreating process involving gas-liquid-solid three-phase,a trickle bed reactor model was established,and a diesel hydrogen solubility model was coupled in the model.Then,the linear free energy relationship and quantitative structure-reactivity correlations were used to reduce the dimension of the fitting parameters.Three sets of experimental data were used to solve the kinetic parameters.The aromatic hydrocarbons and sulfur elements in the product were changed with reaction time concentration in the reactor.Yields of major products at different temperatures were predicted. |
