Mass Spectrometry, High‐Resolution, (Homolog)‐Type Analysis of Petroleum and Synfuel Distillates and Refinery Streams

Abstract

The complex chemistry and chemical engineering of fossil fuel materials including petroleums, coal‐derived liquids, tar sands, shale oils, refinery streams and refined products can often be adequately simplified by expressing the composition of these materials in terms of group types. Group (chemical) types are series of homologous compounds that exhibit similar chemical properties and a regular gradation of physical properties. A homologous series of compounds, the members of which are termed homologs, contains compounds in which successive members exhibit the same difference in chemical formula with the homologous unit of present interest being CH 2 . Mass spectrometry (MS) is an ideal, extensively used technique in analyzing for chemical types in terms either of the total amounts of the various homologous series of compounds present in a sample or of the individual members (homologs) of the various series of homologous compounds present in a sample. The focus of this article is the fundamentals of homolog‐type analysis because analyses expressed in terms of the amounts of individual homologs rather then in terms of the total amounts of group types benefits the understanding/prediction of the effect of experimental conditions on feedstock production/transportation, product distributions in feedstock refining, end‐product quality and environmental impacts. A homolog‐type analysis also permits the determination/prediction of chemical/physical properties of a sample that can be expressed as a function of composition; examples being reaction rates, distillation curves and elemental analyses. The discussion of techniques for obtaining the “molecular ion mass spectra” required to produce homolog‐type analyses focuses on the use of all glass heated inlet systems (AGHIS) and direct probes for sample introduction, low‐voltage electrons for ion formation, and double focusing magnetic sector (DF) and Fourier transform ion cyclotron resonance (FTICR) mass analyzers to resolve isobaric ions.