Heavy Petroleum Composition. 3. Asphaltene Aggregation

Citations Over TimeTop 1% of 2013 papers

Abstract

Molecular characterization of asphaltenes by conventional analytical techniques is a challenge because of their compositional complexity, high heteroatom content, and asphaltene aggregate formation at low concentrations. Thus, most common characterization techniques rely on bulk properties or solution-phase behavior (solubility). Proposed over 20 years ago, the Boduszynski model proposes a continuous progression in petroleum composition (molecular weight, structure, and heteroatom content) as a function of the atmospheric equivalent boiling point. Although exhaustive detailed compositional analysis of petroleum distillates validates the continuum model, the available compositional data from asphaltene fractions supports the extension of the continuum model into the nondistillables only indirectly. Asphaltenes, defined by their insolubility in alkane solvents, accumulate in high-boiling fractions and form stable aggregate structures at low parts per billion (ppb) concentrations, far below the concentration required for most mass analyzers. Here, we present direct mass spectral detection of stable asphaltene aggregates at lower concentrations than previously published and observe the onset of asphaltene nanoaggregate formation by time-of-flight mass spectrometry (TOF–MS). We conclude that a fraction of asphaltenes must be present as nanoaggregates (not monomers) in all atmospheric pressure and laser-based ionization methods. Thus, those methods access a subset of the asphaltene continuum.

Related Papers

• → Molecular Dynamics Study of Nanoaggregation in Asphaltene Mixtures: Effects of the N, O, and S Heteroatoms(2016)96 cited
• → Changes in structural-group characteristics of resins and asphaltenes of heavy oils in the primary distillation process(2017)24 cited
• → Retention of Alkane Compounds on Asphaltenes. Insights About the Nature of Asphaltene–Alkane Interactions(2016)28 cited
• → Precision and Relative Bias of Automatic and Manual D 1078 Distillation(2002)
• Separation and Purification of Organic Mixture and Its Mensuration of Boiling Point Under Ordinary Pressure(2005)