Correlation for Predicting Corrosivity of Crude Oils Using Proton Nuclear Magnetic Resonance and Chemometric Methods

Abstract

Naphthenic acids and sulfur compounds cause corrosion problems in the crude distillation units. Their heterogeneity in the concentration and reactivity makes it difficult to predict the corrosivity of crude oils. In this paper, the areas of resonance signals belonging to 12 chemical shift regions of the proton nuclear magnetic resonance ( 1 H NMR) spectra of crude oils were correlated with the corrosion rate of AISI SAE 1005 carbon steel using a partial least squares regression. The corrosion rates were determined by weight loss tests at 350 °C for 12 h. In addition, a correlation to calculate the corrosion rate based only on the acidity and sulfur percentage of crude oils was proposed for the same crude oil samples. A statistical comparison of the proposed correlations indicates that the 1 H NMR-based correlation has better quality in predicting corrosivity of crude oils. The combination of 1 H NMR spectroscopy with chemometric techniques provides a fast alternative method for quantitative prediction of the corrosion rate at typical operation temperatures of crude distillation units.

Silver-Ion Solid Phase Extraction Separation of Classical, Aromatic, Oxidized, and Heteroatomic Naphthenic Acids from Oil Sands Process-Affected Water

“…11 NAs are also the primary reason for corrosion damage to oil refinery equipment, with sulfur-containing compounds playing an important role. 26 It is expected that distinct NA species can be separated, paving the way to other related studies. In this work, Ag-ion SPE was used to fractionate O x −NAs and O y S−NAs from unprocessed and ozonated OSPWs, and the determination and characterization of fractions were performed using UPLC-IM-TOFMS and MS/ MS analyses.…”

“…Previous toxicological studies have compared the toxicity in aromatic and nonaromatic species, and a similar assessment has not been performed widely on distinct NA species (e.g., oxidized or heteroatomic NA species) because they are not readily separated . NAs are also the primary reason for corrosion damage to oil refinery equipment, with sulfur-containing compounds playing an important role . It is expected that distinct NA species can be separated, paving the way to other related studies.…”

Prediction of the Penetration Grade and Softening Point of Vacuum Residues and Asphalts by Nuclear Magnetic Resonance and Chemometric Methods

“…The square root of the mean-square error is a measure of the standard error of the random component in the estimate. It is expressed in the same units of the parameters and is given by the following equation where V represents the variable of interest; the subscripts “exp” and “cal” refer to the experimental and calculated data, respectively; is the average of the experimental data; N is the number of data points used in the adjustment; and N p is the number of model parameters.…”

Methodology for the Development of Empirical Models Relating 13C NMR Spectral Features to Fuel Properties

“…NMR has previously been applied to link chemical structures within fuels to fuel properties. Table S1 in the Supporting Information, − provides a bibliography of key references where properties important to fossil fuel production and performance, such as ignition characteristics, physical properties, distillation temperatures, soot, and several others, are related using mathematical models to resonances observed in one-dimensional (1-D) 1 H, 13 C, or two-dimensional (2-D) 1 H– 13 C HSQC NMR spectra. Establishing these mathematical relationships is possible because 13 C and 1 H NMR provide detailed, molecular-level information about a substance using very small samples.…”