Application of Low-Field NMR for the Determination of Physical Properties of Petroleum Fractions

Abstract

We propose the use of the low-field 1 H NMR technique to predict various properties of petroleum fractions with °API ranging from 21.7 to 32.7. The experimental data obtained by standard methodologies (ASTM D-1218, D 445-06, D-664-06, D-2892, and D-4052) were correlated with the mean values of the 1 H transverse relaxation time in the range between 25 and 675 ms. Results of the present work showed good correlations between the NMR relaxation data with viscosity, total acid number, refractive index, and API gravity. The main advantage of the proposed method is its nondestructiveness, together with its speed and the fact that it does not require solvents/dilution. This allows the assessment of several properties of petroleum fractions simultaneously, based on the output of only one NMR experiment, leading to large economy in terms of energy, time, and costs.

Molecular Properties of Fatty Acid Mixtures Estimated by Online Time-Domain NMR

“…The average RSEs between the reference and TD-NMR values did not exceed 2.4%, so the application of this online test to industrial quality control is promising. The acquired results are in good agreement with the results of the previous investigations [20], where several quality parameters of petroleum fractions correlated with R 2 or lnT 2 . These authors also used the major peak of the inverse Laplace distribution of the transverse magnetization decays of petroleum fractions to correlate the NMR values with quality parameters, while the minor peak in the distribution was considered an artefact and neglected.…”

“…TD-NMR has been proposed as an alternative technique to predict several liquid fuel properties, such as the cetane index, density, flash point, temperature to achieve 50% distillation of a sample (T50) [19], biodiesel content of diesel fuel [14], viscosity, refractive index, American Petroleum Institute (API) gravity [20], total acid number [20,21], and sulphur content [21] in petroleum fractions. The fatty acid composition, viscosity, CN, and iodine content of different intact oilseeds were estimated using 1 H transverse relaxation time T 2 data combined with chemometric techniques [22].…”

Rapid and simultaneous relaxometric methods to study paramagnetic ion complexes in solution: An alternative to spectrophotometry

“…quality control processes for more than four decades [12], replacing laborious and time-consuming traditional methods in food [13,14], petrochemical [15,16] and cosmetic industries [17].…”

New Experimental Approaches to Analyse the Supramolecular Structure of Rejuvenated Aged Bitumens

“…In particular, the powerful ILT method applied to the experimental NMR echo decay can be exploited to test the effectiveness of the real rejuvenator. Indeed, direct correlation can be made between T 2 and the rigidity of structures in these materials as well as the molecular constrain causing dynamic hindrance [29].…”