Studies of asphaltenes by the use of pulsed-field gradient spin echo NMR

Jenny-Ann Östlund, Sven Ingvar Andersson, Magnus Nydén*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

47 Citations (Scopus)

Abstract

Pulsed field gradient spin echo nuclear magnetic resonance (PFG-SE NMR) has been used to study the self-diffusion of asphaltenes in deuterated toluene. Diffusion coefficients of n-heptane asphaltenes were measured in the concentration range of 0.044-5 wt%. It is shown that the self-diffusion of asphaltenes is well described by a log-normal distribution of diffusion coefficients and that the width of the obtained distribution is broad and independent of the asphaltene concentration in the interval studied. Both asphaltene and toluene diffusion indicates that asphaltenes have a disc-like shape as revealed by a strong concentration dependence on the diffusion coefficients. The diffusion coefficient of asphaltenes at infinite dilution was 2.2×10-10 m2/s.

Original languageEnglish
Pages (from-to)1529-1533
Number of pages5
JournalFuel
Volume80
Issue number11
DOIs
Publication statusPublished - Sep 2001
Externally publishedYes

Keywords

  • Asphaltenes
  • Size
  • Shape
  • Nuclear magnetic resonance
  • Self-diffusion
  • Pulsed field gradient spin echo nuclear magnetic resonance

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