1H Benchtop NMR Analysis of Physical and Chemical Properties of Diesel Fuel

1H Benchtop NMR has great potential to increase the throughput of both routine and emergency fuel sample analysis in refinery laboratories. Currently fuel samples must be passed through multiple dedicated analyzers to obtain information such as density, H-Content, aromatics, olefins, saturates, benzene,
Octane numbers, cetane index, cetane number, distillation curves, vapor pressure, flash point, pour point, freeze point, cloud point, etc. Correlation of the 1H NMR spectra of these refinery fuel samples to these primary test results will allow all parameters to be predicted in about 40 seconds from the 4 pulse spectrum of the pure fuel. Here we have a few examples obtained on some diesel fuels that were submitted to our lab for ASTM D7171 – Hydrogen Content by TD-NMR. We had density, H-content, and aromatics wt% by GC. Below are three example correlation obtained on the Picospin 80 system (that requires 32 pulses per sample due to the capillary sample size). The results were very similar for the 300, 60, and 42 MHz data obtained on the three other NMR system in our laboratory. The comparative results are shown in Table II. The results are very similar independent of the field strength of the NMR system. The data from all 4 NMR systems is provided in this section.

300 MHz 1H NMR - Diesel Fuels

300 MHz 1H NMR – Diesel Fuels

80 MHz 1H NMR - Diesel Fuels

80 MHz 1H NMR – Diesel Fuels

60 MHz 1H NMR - Diesel Fuels

60 MHz 1H NMR – Diesel Fuels

43 MHz 1H NMR - Diesel Fuels

43 MHz 1H NMR – Diesel Fuels

1H NMR and Density Correlated by PLS Regression Analysis

1H NMR and Density Correlated by PLS Regression Analysis

1H NMR andAromatic Content (Wt% GC) Correlated by PLS Regression Analysis

1H NMR andAromatic Content (Wt% GC) Correlated by PLS Regression Analysis

1H NMR and Hydrogen Content (Wt% TD-NMR ASTM D7171) Correlated by PLS Regression Analysis

Summary Table of Regression Models

Summary Table of Regression Models