The asphalt and the ESR analysis of vanadium in the crude oil can determine the quality of crude oil

Currently, about a third of the world's energy comes from crude oil.The chemical composition of crude oil determines its quality, will affect its processing, performance, and the market price.Therefore, the status of crude oil for qualitative and quantitative monitoring is indispensable.

Crude oil composition is the greatest influence on oil quality in the asphalt, it is also the heaviest components in crude oil.Composition of the asphaltenes is polycyclic aromatic hydrocarbons and aliphatic side chain compounds and trace amounts of nickel and vanadium complex mixture formation.Low concentration of asphaltenes are prone to aggregation, leading to its viscosity increases, and in the process of oil exploitation and plugging wellbore and oil pipeline.In addition, the asphalt will cause the mass and catalytic reaction in the process of refining the deactivation.

Analysis of complex mixture of hydrocarbons in crude oil asphaltene concentration is very difficult, especially for online monitoring.The traditional measuring method is measuring the viscosity of the crude oil and dielectric constant physical properties, such as and then use these data to determine the chemical composition of potential.When analyzing specific bituminous, usually in system or diluted to a simple model to measure in the solvents in the sample.

Electron spin resonance (ESR), or the introduction of the electron paramagnetic resonance (EPR) have been able to direct the asphaltenes were characterized.The technology provides high resolution and quantitative data, and can reflect the true dynamic information in the local environment.In addition, the ESR is a nondestructive testing method, no sample preparation.

The ESR using static magnetic resonance absorption of microwave in the measurement of molecules with unpaired electrons and contains paramagnetic center system.Asphaltene core contains organic free radicals, polycyclic aromatic hydrocarbons in the g = 2.0032 can show the typical ESR signal, thus it is easy to be recognized in the crude oil.

GaiFeng amplitude and asphaltene concentration in the sample, so the technology can also be used for quantitative analysis.In addition, the ESR can detect vanadium, can put the vanadium vanadium porphyrin as a kind of oxygen to observe, it is similar to those of asphaltenes organic free radical signal area is shown as eight wide spacing of narrow peaks.

By monitoring the various characteristics of these ingredients, can have a better understanding of the crude oil composition and chemical changes.Previously, the ESR has been able to distinguish between different types of crude oil, but in recent years, people began to more specific criteria for analysis.

Biodegradation is one of the main process changes crude oil composition and quality.Be oxidized in the process, hydrocarbon, generates carbon dioxide and organic acids, which led to the decrease of the saturated hydrocarbon and aromatic hydrocarbon concentration, viscosity, metal content and acidity.

To three Brazilian crude oil to a recent study of the process were compared, by using the ESR to monitor whether existence and porphyrin compounds in crude oil related or unrelated organic oxygen free radicals and vanadium species.This method can be quantified by signal value will be two samples of biodegradation and abiotic degradation of samples, and the two samples of biodegradable distinguish each other.

Temperature also affects the behavior of organic free radical species in the crude oil and the characteristics of the structure, so as to affect the quality of crude oil.Recently conducted a study on these changes, the use of the in situ ESR to monitor in the temperature range of 293-673 K samples of different fractions of crude oil.

For all fractions, temperature rise will lead to increased organic free radical species, however, the mechanism of this process has been found to occur owing to the different fraction.Atmospheric residue and crude oil fractions appear similar, around 433 K organic free radicals, and vacuum residuum organic free radicals produced in the form of a multi-step process.

Most of the ESR spectrometer large and heavy, this restricts their ability to online real-time analysis for crude oil.Optical and wireless communication technology advances, however, brooke developed a minimum of ESR spectrometer on the market - microESR, it is small, mobile light, covers an area of 30.5 x 30.5 x 30.5 cm after, weighs only 10 kg.

MicroESR without any scheduled maintenance or special installation.

MicroESR also for ESR data acquisition, processing and analysis software provides a simple workflow.

With ESR in the progress of the analysis on the application of crude oil, microESR can be used for on-line monitoring tool, to characterize in exploration, production and refining of crude oil chemical composition in the process of operation.

This analysis can be used in many applications, including assessment of crude oil of artificial aging, and predicted possible problems in the process of operation further.

De Abreu, c. R., et al. (202).
The Application of the Electron Spin Resonance Technique in the Characterization of Brazilian Oils: the Correlation with Their Biodegradation Level and Polar Composition. The Energy Fuels.
https://dx.doi.org/10.1021/acs.energyfuels.0c02624

Dappe, V., et al. (2020).
Effect of Thermal Treatment of company's Petroleum Fractions: Characterization by the In Situ EPR Spectroscopy. The Energy Fuels.
https://dx.doi.org/10.1021/acs.energyfuels.0c01504

Brooke's website microESR page for details