Quantitative Characterization Of Heteroatomic Compounds In Heavy Petroleum At Molecules Level

Diversification of material sources and increasingly stringent environmental requirements led to a significant reduction in the profit of the oil processing industry.Simulation and adjust of the refinering process in the molecular level has become a research focus.The qualitative and quantitative characterization of petroleum molecular composition is the basis of further research relevant to molecular management.In this paper,a series of separation methods and analytical methods based on high resolution mass spectrometry were used to establish a quantitative analysis methods for the molecular composition of heteroatom compounds in heavy petroleum.(1)A method for rapid elimination of mass discrimination was established for FTICR MS during ion transport.Using the series of fatty acid samples as the reference standard,the Gaussian distribution was used to simulate the mass spectrum discrimination under different sampling conditions.Based on the results of Gaussian distribution,mass spectrometry mass discrimination calibration method was established,and tested on standard samples and crude petroleum.This method is not required for special mass spectrometer support and can be used to quickly calibrate wide range of crude petroleum or heavy petroleum.(2)Two quantitative characterization methods of heteroatomic compounds in petroleum at molecular level based on internal standard and normalization were developed.And the accuracy and scope of the two methods were determined.It is the preferred method to quantify the molecular composition of the heavy oil heteroatom compound by quantitative characterization method based on normalization with the macroscopic parameters such as element,acid value and alkali nitrogen value.Under some conditions,the internal standard method can be applied to the determination of strong polar compounds in petroleum.The weakly polar compounds need to be derivatized before they can be quantitative characterized.(3)The quantitative characterization methods of three main heteroatom compounds at molecular level,such as oxygen,nitrogen and sulfur,were established respectively,which were suitable for petroleum distillate analysis.For the oxygen compounds,a normalized quantitative characterization method based on separating the oxygen compounds by potassium hydroxide modified silica and element content of oxygen was established.At the same time,a normalization quantitative characterization method based on acid value and internal standard quantitative characterization method based on deuterated octadecyl fatty acid were established.For the nitrogen compounds,a normalized quantitative characterization method based on separating the nitrogen compounds by hydrochloric acid modified silica and element content of nitrogen was established.In the meaning time,another normalization quantitative characterization method based on alkali-nitrogen titration were established for nitrogen compounds.For the sulfur compounds,a normalization quantitative characterization method based on the methylation-fractional demethylation method for the separation and determination of the sulfur element content was established.(4)The quantitative discrimination method and the quantitative characterizaion of oxygen,nitrogen and sulfur were integrated and applied in vacuum residue.The data were calibrated and integrated for heavy petroleum.Based on ESI FT-ICR MS,the quantitative characterization scheme of the heteroatom compounds in heavy oil at molecular level was obtained.This paper successfully established a method based on ESI FT-ICR MS to quantitatively analyze the heteroatom compounds in heavy oil on molecular level.And laying a framework to further quantitatively analyze the remaining compounds in heavy oil.Detailed molecular composition analysis will provide strong support for heavy oil processing and utilization on molecular level,and provides theoretical guidance for petroleum processing development.