Enrichment Of Waxy Components In Fushun Shale Oil And Preparation Of Refined Paraffin

Shale oil?SO?derived from the pyrolysis of oil shale,and its chemical composition can be roughly divided into aliphatic hydrocarbons,aromatic hydrocarbons,oxygen-containing organic compounds,nitrogen-containing organic compounds,and sulfur-containing organic compounds.SO is regarded as the ideal raw material for producing refined paraffin?RP?due to its high content of n-alkanes.Paraffin is usually separated from petroleum wax fractions,and SO is mainly used for hydrogenation and reforming to produce liquid fuels.Therefore,the preparation of RP using SO as a raw material has important practical significance,not only can obtain value-added chemicals,but also provides a new way for non-fuel utilization of SO.Firstly,the effect of the volume ratio of polar solvent and non-polar solvent on their intersolubility was explored.The results show that the two solvents with a volume ratio of 1:4?polar:nonpolar?have the lowest intersolubility.The extraction results of SO with 8 dual-solvents?DSs?indicat that the selectivity of acetonitrile/petroleum ether was the highest,and the optimal extraction conditions were determinated as:DS/SO ratio of 10 mL g^-1,extraction time30 min,and 3 times.The model oil was formulated according to the group components and their relative contents?RCs?in the SO,and the extraction performance of the DS with the highest selectivity was verified under the optimal conditions.GC/MS analyses of polar and non-polar phases show that arenes and heteroatomic compounds could be enriched in acetonitrile,while aliphatic hydrocarbons were trapped in petroleum ether.Based on the UV-Vis spectra of samples that containing waxy components with different concentrations,the index for evaluating the adsorption effect were determined,and orthogonal experiments were designed to optimize the experimental conditions for the decolorization of waxy components.The results show that using silica gel as the adsorbent,the amount of which is 20%?wt?of the waxy component,after 60 minutes of adsorption at a constant temperature of60 ^oC,the single-stage decolorization rate can reach 43.42%,and the total decolorization rate was increased to 58.81%after 3 times of adsorption under the same conditions.The discolored slack wax?SW?was recrystallized in the polar solvent,and the effects of solvent type and solvent/wax ratio on the yield of RP and the total RC of oil were investigated.GC/MS analysis results show that the yield and oil content of RP decrease with increasing the solvent/wax ratio.Under the same ratio of solvent to wax,the yield of RP gradually increases in this order:ethyl acetate,isopropanol,acetone,and ethanol,respectively.When the solvent/wax ratio is 10 mL g^-1,the total RC of oil in all RPs are less than 1%,the yields are 10.09,20.33,24.72,and 29.04%,respectively;while the oil contents are 0.12,0.28,0.59,and 0.75%,respectively.The chemical composition of the 4 RPs are mainly long-chain alkanes with carbon numbers from 10 to 33,which are consistent with their FTIR spectral analysis results.Obviously,it is feasible to prepare RP with different oil content by changing the polarity of solvent and the ratio of solvent/wax in the process of SW recrystallization.The weak interaction between acetonitrile and arenes/heteroatomic compounds is the main reason for the high selective enrichment of waxy components with DS.The analysis results of the electrostatic potential?ESP?and the average local ionization energy?ALIE?on the molecular surface show that acetonitrile can use lone pair electrons on the N atom and?electrons on the C?N as electron donors,also can use hydrogen atoms on the methyl group as electron acceptors.Therefore,it is can be inferred that C-H···?weak hydrogen bonds,X···H-Y strong hydrogen bonds,and weak?···?stacking effect exist between acetonitrile and the model compounds.The solvation free energies of the model compound in acetonitrile and n-hexane sufficiently explain the high selectivity of the DS,which indicates that the appropriate solvent can be screened by calculating the solvation free energy of the solute in the solvent.This study provides theoretical guidance for isolating the target components from similar systems.There are 44 figures,27 tables and 99 references in this thesis.