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Papers by Robson R Moura

Research paper thumbnail of Corrosion rate studies of AISI 1020 steel using linear, cyclic, and aromatic naphthenic acid standards

Journal of Petroleum Science and Engineering, 2020

The use of total acid number (TAN) to measure the acidity of crude oil samples is a common practi... more The use of total acid number (TAN) to measure the acidity of crude oil samples is a common practice. Daily practice in petroleum refineries shows that oil with a TAN less than 0.5 mg KOH g −1 can usually have unexpected corrosive behavior. Although naphthenic corrosion has been studied for many years, its process is not entirely understood. Therefore, this study investigated the influence of linear, cyclic and aromatic NAs molecules, evaluating the effect of their concentrations, molar weight (M w), structural and electronic properties on the corrosion rate of AISI 1020 steel samples at 320°C. The type and extension of corrosion were determined by surface characterization of the sample using optical microscopy (LM), atomic force microscopy (AFM), and scanning electron microscopy (SEM). The results showed that even when TAN was below the detection limit, the corrosion rate (CR) value was significant (CR < 0.19 mm year −1) and considered high for the industry. For concentrations of benzoic (BENA) and stearic (STA) acids higher than 5000 ppm, the corrosion rate varied proportionally with the TAN. Also, there was an inverse proportional correlation between molecular weight (M w), the number of aromatic rings and NAs corrosiveness. In general, NAs standards containing a lower molar volume were found to cause a higher corrosion rate. SEM micrographs revealed changes in the surface area of all samples exposed to linear, cyclic and aromatic NAs, indicating the formation of a protective layer under the surface of the carbon steel specimen. AFM imaging showed drastic changes in the topographic profile and phase images characterized by the formation of valleys and peaks, as well as variations in the mechanical properties of the surface of the AISI 1020 steel sample. Results obtained in this study confirm the influence of the electronicstructural properties of the molecules of organic acids on the naphthenic corrosion. This observation can be confirmed by the behavior of Athabasca crude oil, which demonstrates high corrosion rates, even having low

Research paper thumbnail of De Mensen Hoodie s van Streetwear van de Manier van het Embleem van de Douane van de Prijs van de Fabriek van Hip Hop

Journal of the Brazilian Chemical Society, Aug 1, 2018

Microscopic techniques were combined to study the influence of corrosion rate on the morphologic ... more Microscopic techniques were combined to study the influence of corrosion rate on the morphologic behavior of AISI 1020 steel specimens submitted to thermal degradation of a typical acid crude oil (total acid number (TAN) = 2.1390 mg KOH g-1 and total sulfur (S) = 0.7778 wt.%). The techniques used were light microscopy (LM), scanning electron microscopy/energy dispersive spectroscopy (SEM/EDX), atomic force microscopy (AFM) as well as Raman spectroscopy. Assays were performed in six different degradation time (t = 6, 12, 24, 36, 48 and 72 h) at 320 °C. After the exposure of the specimens to petroleum, a reduction above 37% in the TAN after t = 72 h was observed, with a maximum corrosion rate during the first periods of degradation (t = 6 and 12 h). Correlating the TAN and corrosion rate data with the microscopic data, the images of LM, AFM, and SEM/EDX showed that after 6 h of exposure to petroleum, a passivation film was formed on the surface of the steel. This film consisted of two layers, an external one, formed of FeS, and an internal one, composed of iron oxides and oxyhydroxides. However, after 48 h of thermal degradation, this morphology was altered to a single layer of FeS coating the steel surface.

Research paper thumbnail of 3D Machine van de Pers van de Hitte van de Film Vacuüm met Infrarode het Verwarmen Functie (iNV-3Dpro)

Journal of the Brazilian Chemical Society, Aug 1, 2018

Microscopic techniques were combined to study the influence of corrosion rate on the morphologic ... more Microscopic techniques were combined to study the influence of corrosion rate on the morphologic behavior of AISI 1020 steel specimens submitted to thermal degradation of a typical acid crude oil (total acid number (TAN) = 2.1390 mg KOH g-1 and total sulfur (S) = 0.7778 wt.%). The techniques used were light microscopy (LM), scanning electron microscopy/energy dispersive spectroscopy (SEM/EDX), atomic force microscopy (AFM) as well as Raman spectroscopy. Assays were performed in six different degradation time (t = 6, 12, 24, 36, 48 and 72 h) at 320 °C. After the exposure of the specimens to petroleum, a reduction above 37% in the TAN after t = 72 h was observed, with a maximum corrosion rate during the first periods of degradation (t = 6 and 12 h). Correlating the TAN and corrosion rate data with the microscopic data, the images of LM, AFM, and SEM/EDX showed that after 6 h of exposure to petroleum, a passivation film was formed on the surface of the steel. This film consisted of two layers, an external one, formed of FeS, and an internal one, composed of iron oxides and oxyhydroxides. However, after 48 h of thermal degradation, this morphology was altered to a single layer of FeS coating the steel surface.

Research paper thumbnail of De in het groot Pyjama's Organische Lycra Van uitstekende kwaliteit van Kinderen voor de Kleren van de Baby

Journal of the Brazilian Chemical Society, Aug 1, 2018

Microscopic techniques were combined to study the influence of corrosion rate on the morphologic ... more Microscopic techniques were combined to study the influence of corrosion rate on the morphologic behavior of AISI 1020 steel specimens submitted to thermal degradation of a typical acid crude oil (total acid number (TAN) = 2.1390 mg KOH g-1 and total sulfur (S) = 0.7778 wt.%). The techniques used were light microscopy (LM), scanning electron microscopy/energy dispersive spectroscopy (SEM/EDX), atomic force microscopy (AFM) as well as Raman spectroscopy. Assays were performed in six different degradation time (t = 6, 12, 24, 36, 48 and 72 h) at 320 °C. After the exposure of the specimens to petroleum, a reduction above 37% in the TAN after t = 72 h was observed, with a maximum corrosion rate during the first periods of degradation (t = 6 and 12 h). Correlating the TAN and corrosion rate data with the microscopic data, the images of LM, AFM, and SEM/EDX showed that after 6 h of exposure to petroleum, a passivation film was formed on the surface of the steel. This film consisted of two layers, an external one, formed of FeS, and an internal one, composed of iron oxides and oxyhydroxides. However, after 48 h of thermal degradation, this morphology was altered to a single layer of FeS coating the steel surface.

Research paper thumbnail of Hoge Efficiency van het Zonne paneel van 325 Watts Poly CEI- Ce- Certificaat

Journal of the Brazilian Chemical Society, Aug 1, 2018

Microscopic techniques were combined to study the influence of corrosion rate on the morphologic ... more Microscopic techniques were combined to study the influence of corrosion rate on the morphologic behavior of AISI 1020 steel specimens submitted to thermal degradation of a typical acid crude oil (total acid number (TAN) = 2.1390 mg KOH g-1 and total sulfur (S) = 0.7778 wt.%). The techniques used were light microscopy (LM), scanning electron microscopy/energy dispersive spectroscopy (SEM/EDX), atomic force microscopy (AFM) as well as Raman spectroscopy. Assays were performed in six different degradation time (t = 6, 12, 24, 36, 48 and 72 h) at 320 °C. After the exposure of the specimens to petroleum, a reduction above 37% in the TAN after t = 72 h was observed, with a maximum corrosion rate during the first periods of degradation (t = 6 and 12 h). Correlating the TAN and corrosion rate data with the microscopic data, the images of LM, AFM, and SEM/EDX showed that after 6 h of exposure to petroleum, a passivation film was formed on the surface of the steel. This film consisted of two layers, an external one, formed of FeS, and an internal one, composed of iron oxides and oxyhydroxides. However, after 48 h of thermal degradation, this morphology was altered to a single layer of FeS coating the steel surface.

Research paper thumbnail of De Delen van de Opschorting van de auto voor AutomobielDelen

Journal of the Brazilian Chemical Society, Aug 1, 2018

Microscopic techniques were combined to study the influence of corrosion rate on the morphologic ... more Microscopic techniques were combined to study the influence of corrosion rate on the morphologic behavior of AISI 1020 steel specimens submitted to thermal degradation of a typical acid crude oil (total acid number (TAN) = 2.1390 mg KOH g-1 and total sulfur (S) = 0.7778 wt.%). The techniques used were light microscopy (LM), scanning electron microscopy/energy dispersive spectroscopy (SEM/EDX), atomic force microscopy (AFM) as well as Raman spectroscopy. Assays were performed in six different degradation time (t = 6, 12, 24, 36, 48 and 72 h) at 320 °C. After the exposure of the specimens to petroleum, a reduction above 37% in the TAN after t = 72 h was observed, with a maximum corrosion rate during the first periods of degradation (t = 6 and 12 h). Correlating the TAN and corrosion rate data with the microscopic data, the images of LM, AFM, and SEM/EDX showed that after 6 h of exposure to petroleum, a passivation film was formed on the surface of the steel. This film consisted of two layers, an external one, formed of FeS, and an internal one, composed of iron oxides and oxyhydroxides. However, after 48 h of thermal degradation, this morphology was altered to a single layer of FeS coating the steel surface.

Research paper thumbnail of Y83-500 de Pers van het Briketteren van de Schroot

Journal of the Brazilian Chemical Society, Aug 1, 2018

Microscopic techniques were combined to study the influence of corrosion rate on the morphologic ... more Microscopic techniques were combined to study the influence of corrosion rate on the morphologic behavior of AISI 1020 steel specimens submitted to thermal degradation of a typical acid crude oil (total acid number (TAN) = 2.1390 mg KOH g-1 and total sulfur (S) = 0.7778 wt.%). The techniques used were light microscopy (LM), scanning electron microscopy/energy dispersive spectroscopy (SEM/EDX), atomic force microscopy (AFM) as well as Raman spectroscopy. Assays were performed in six different degradation time (t = 6, 12, 24, 36, 48 and 72 h) at 320 °C. After the exposure of the specimens to petroleum, a reduction above 37% in the TAN after t = 72 h was observed, with a maximum corrosion rate during the first periods of degradation (t = 6 and 12 h). Correlating the TAN and corrosion rate data with the microscopic data, the images of LM, AFM, and SEM/EDX showed that after 6 h of exposure to petroleum, a passivation film was formed on the surface of the steel. This film consisted of two layers, an external one, formed of FeS, and an internal one, composed of iron oxides and oxyhydroxides. However, after 48 h of thermal degradation, this morphology was altered to a single layer of FeS coating the steel surface.

Research paper thumbnail of De Machine van de Pers van de Hitte van GLB

Journal of the Brazilian Chemical Society, Aug 1, 2018

Microscopic techniques were combined to study the influence of corrosion rate on the morphologic ... more Microscopic techniques were combined to study the influence of corrosion rate on the morphologic behavior of AISI 1020 steel specimens submitted to thermal degradation of a typical acid crude oil (total acid number (TAN) = 2.1390 mg KOH g-1 and total sulfur (S) = 0.7778 wt.%). The techniques used were light microscopy (LM), scanning electron microscopy/energy dispersive spectroscopy (SEM/EDX), atomic force microscopy (AFM) as well as Raman spectroscopy. Assays were performed in six different degradation time (t = 6, 12, 24, 36, 48 and 72 h) at 320 °C. After the exposure of the specimens to petroleum, a reduction above 37% in the TAN after t = 72 h was observed, with a maximum corrosion rate during the first periods of degradation (t = 6 and 12 h). Correlating the TAN and corrosion rate data with the microscopic data, the images of LM, AFM, and SEM/EDX showed that after 6 h of exposure to petroleum, a passivation film was formed on the surface of the steel. This film consisted of two layers, an external one, formed of FeS, and an internal one, composed of iron oxides and oxyhydroxides. However, after 48 h of thermal degradation, this morphology was altered to a single layer of FeS coating the steel surface.

Research paper thumbnail of 2400mAh reusachtige Capaciteit Ecigarette DNA30

Journal of the Brazilian Chemical Society, Aug 1, 2018

Microscopic techniques were combined to study the influence of corrosion rate on the morphologic ... more Microscopic techniques were combined to study the influence of corrosion rate on the morphologic behavior of AISI 1020 steel specimens submitted to thermal degradation of a typical acid crude oil (total acid number (TAN) = 2.1390 mg KOH g-1 and total sulfur (S) = 0.7778 wt.%). The techniques used were light microscopy (LM), scanning electron microscopy/energy dispersive spectroscopy (SEM/EDX), atomic force microscopy (AFM) as well as Raman spectroscopy. Assays were performed in six different degradation time (t = 6, 12, 24, 36, 48 and 72 h) at 320 °C. After the exposure of the specimens to petroleum, a reduction above 37% in the TAN after t = 72 h was observed, with a maximum corrosion rate during the first periods of degradation (t = 6 and 12 h). Correlating the TAN and corrosion rate data with the microscopic data, the images of LM, AFM, and SEM/EDX showed that after 6 h of exposure to petroleum, a passivation film was formed on the surface of the steel. This film consisted of two layers, an external one, formed of FeS, and an internal one, composed of iron oxides and oxyhydroxides. However, after 48 h of thermal degradation, this morphology was altered to a single layer of FeS coating the steel surface.

Research paper thumbnail of De in het groot van de Katoenen van 100% Nieuwe Kleding Jonge geitjes van de Douane - de geboren Kleren van de Baby

Journal of the Brazilian Chemical Society, Aug 1, 2018

Microscopic techniques were combined to study the influence of corrosion rate on the morphologic ... more Microscopic techniques were combined to study the influence of corrosion rate on the morphologic behavior of AISI 1020 steel specimens submitted to thermal degradation of a typical acid crude oil (total acid number (TAN) = 2.1390 mg KOH g-1 and total sulfur (S) = 0.7778 wt.%). The techniques used were light microscopy (LM), scanning electron microscopy/energy dispersive spectroscopy (SEM/EDX), atomic force microscopy (AFM) as well as Raman spectroscopy. Assays were performed in six different degradation time (t = 6, 12, 24, 36, 48 and 72 h) at 320 °C. After the exposure of the specimens to petroleum, a reduction above 37% in the TAN after t = 72 h was observed, with a maximum corrosion rate during the first periods of degradation (t = 6 and 12 h). Correlating the TAN and corrosion rate data with the microscopic data, the images of LM, AFM, and SEM/EDX showed that after 6 h of exposure to petroleum, a passivation film was formed on the surface of the steel. This film consisted of two layers, an external one, formed of FeS, and an internal one, composed of iron oxides and oxyhydroxides. However, after 48 h of thermal degradation, this morphology was altered to a single layer of FeS coating the steel surface.

Research paper thumbnail of 5000W Toroidal Transformator van de Kern 5000va van de ring

Journal of the Brazilian Chemical Society, Aug 1, 2018

Microscopic techniques were combined to study the influence of corrosion rate on the morphologic ... more Microscopic techniques were combined to study the influence of corrosion rate on the morphologic behavior of AISI 1020 steel specimens submitted to thermal degradation of a typical acid crude oil (total acid number (TAN) = 2.1390 mg KOH g-1 and total sulfur (S) = 0.7778 wt.%). The techniques used were light microscopy (LM), scanning electron microscopy/energy dispersive spectroscopy (SEM/EDX), atomic force microscopy (AFM) as well as Raman spectroscopy. Assays were performed in six different degradation time (t = 6, 12, 24, 36, 48 and 72 h) at 320 °C. After the exposure of the specimens to petroleum, a reduction above 37% in the TAN after t = 72 h was observed, with a maximum corrosion rate during the first periods of degradation (t = 6 and 12 h). Correlating the TAN and corrosion rate data with the microscopic data, the images of LM, AFM, and SEM/EDX showed that after 6 h of exposure to petroleum, a passivation film was formed on the surface of the steel. This film consisted of two layers, an external one, formed of FeS, and an internal one, composed of iron oxides and oxyhydroxides. However, after 48 h of thermal degradation, this morphology was altered to a single layer of FeS coating the steel surface.

Research paper thumbnail of 1350W 4-kanaals versterker voor Stage-luidspreker

Journal of the Brazilian Chemical Society, Aug 1, 2018

Microscopic techniques were combined to study the influence of corrosion rate on the morphologic ... more Microscopic techniques were combined to study the influence of corrosion rate on the morphologic behavior of AISI 1020 steel specimens submitted to thermal degradation of a typical acid crude oil (total acid number (TAN) = 2.1390 mg KOH g-1 and total sulfur (S) = 0.7778 wt.%). The techniques used were light microscopy (LM), scanning electron microscopy/energy dispersive spectroscopy (SEM/EDX), atomic force microscopy (AFM) as well as Raman spectroscopy. Assays were performed in six different degradation time (t = 6, 12, 24, 36, 48 and 72 h) at 320 °C. After the exposure of the specimens to petroleum, a reduction above 37% in the TAN after t = 72 h was observed, with a maximum corrosion rate during the first periods of degradation (t = 6 and 12 h). Correlating the TAN and corrosion rate data with the microscopic data, the images of LM, AFM, and SEM/EDX showed that after 6 h of exposure to petroleum, a passivation film was formed on the surface of the steel. This film consisted of two layers, an external one, formed of FeS, and an internal one, composed of iron oxides and oxyhydroxides. However, after 48 h of thermal degradation, this morphology was altered to a single layer of FeS coating the steel surface.

Research paper thumbnail of Haak Steel304/316 van de Hardware van het optuigen de Roestvrije van Bevestigingsmiddel

Journal of the Brazilian Chemical Society, Aug 1, 2018

Microscopic techniques were combined to study the influence of corrosion rate on the morphologic ... more Microscopic techniques were combined to study the influence of corrosion rate on the morphologic behavior of AISI 1020 steel specimens submitted to thermal degradation of a typical acid crude oil (total acid number (TAN) = 2.1390 mg KOH g-1 and total sulfur (S) = 0.7778 wt.%). The techniques used were light microscopy (LM), scanning electron microscopy/energy dispersive spectroscopy (SEM/EDX), atomic force microscopy (AFM) as well as Raman spectroscopy. Assays were performed in six different degradation time (t = 6, 12, 24, 36, 48 and 72 h) at 320 °C. After the exposure of the specimens to petroleum, a reduction above 37% in the TAN after t = 72 h was observed, with a maximum corrosion rate during the first periods of degradation (t = 6 and 12 h). Correlating the TAN and corrosion rate data with the microscopic data, the images of LM, AFM, and SEM/EDX showed that after 6 h of exposure to petroleum, a passivation film was formed on the surface of the steel. This film consisted of two layers, an external one, formed of FeS, and an internal one, composed of iron oxides and oxyhydroxides. However, after 48 h of thermal degradation, this morphology was altered to a single layer of FeS coating the steel surface.

Research paper thumbnail of Hete het Verkopen Druk 100% Kleren van de Baby van het Katoenen Proces van het Kamgaren Pasgeboren

Journal of the Brazilian Chemical Society, Aug 1, 2018

Microscopic techniques were combined to study the influence of corrosion rate on the morphologic ... more Microscopic techniques were combined to study the influence of corrosion rate on the morphologic behavior of AISI 1020 steel specimens submitted to thermal degradation of a typical acid crude oil (total acid number (TAN) = 2.1390 mg KOH g-1 and total sulfur (S) = 0.7778 wt.%). The techniques used were light microscopy (LM), scanning electron microscopy/energy dispersive spectroscopy (SEM/EDX), atomic force microscopy (AFM) as well as Raman spectroscopy. Assays were performed in six different degradation time (t = 6, 12, 24, 36, 48 and 72 h) at 320 °C. After the exposure of the specimens to petroleum, a reduction above 37% in the TAN after t = 72 h was observed, with a maximum corrosion rate during the first periods of degradation (t = 6 and 12 h). Correlating the TAN and corrosion rate data with the microscopic data, the images of LM, AFM, and SEM/EDX showed that after 6 h of exposure to petroleum, a passivation film was formed on the surface of the steel. This film consisted of two layers, an external one, formed of FeS, and an internal one, composed of iron oxides and oxyhydroxides. However, after 48 h of thermal degradation, this morphology was altered to a single layer of FeS coating the steel surface.

Research paper thumbnail of De Catheter van de Ballon van Kyphoplasty

Journal of the Brazilian Chemical Society, Aug 1, 2018

Microscopic techniques were combined to study the influence of corrosion rate on the morphologic ... more Microscopic techniques were combined to study the influence of corrosion rate on the morphologic behavior of AISI 1020 steel specimens submitted to thermal degradation of a typical acid crude oil (total acid number (TAN) = 2.1390 mg KOH g-1 and total sulfur (S) = 0.7778 wt.%). The techniques used were light microscopy (LM), scanning electron microscopy/energy dispersive spectroscopy (SEM/EDX), atomic force microscopy (AFM) as well as Raman spectroscopy. Assays were performed in six different degradation time (t = 6, 12, 24, 36, 48 and 72 h) at 320 °C. After the exposure of the specimens to petroleum, a reduction above 37% in the TAN after t = 72 h was observed, with a maximum corrosion rate during the first periods of degradation (t = 6 and 12 h). Correlating the TAN and corrosion rate data with the microscopic data, the images of LM, AFM, and SEM/EDX showed that after 6 h of exposure to petroleum, a passivation film was formed on the surface of the steel. This film consisted of two layers, an external one, formed of FeS, and an internal one, composed of iron oxides and oxyhydroxides. However, after 48 h of thermal degradation, this morphology was altered to a single layer of FeS coating the steel surface.

Research paper thumbnail of Study of the Corrosive Behavior of the AISI 1020 Steel in Acid Crude Oil by Microscopic Techniques (LM, AFM and SEM/EDX) and Raman Spectroscopy

Journal of the Brazilian Chemical Society, 2018

Microscopic techniques were combined to study the influence of corrosion rate on the morphologic ... more Microscopic techniques were combined to study the influence of corrosion rate on the morphologic behavior of AISI 1020 steel specimens submitted to thermal degradation of a typical acid crude oil (total acid number (TAN) = 2.1390 mg KOH g-1 and total sulfur (S) = 0.7778 wt.%). The techniques used were light microscopy (LM), scanning electron microscopy/energy dispersive spectroscopy (SEM/EDX), atomic force microscopy (AFM) as well as Raman spectroscopy. Assays were performed in six different degradation time (t = 6, 12, 24, 36, 48 and 72 h) at 320 °C. After the exposure of the specimens to petroleum, a reduction above 37% in the TAN after t = 72 h was observed, with a maximum corrosion rate during the first periods of degradation (t = 6 and 12 h). Correlating the TAN and corrosion rate data with the microscopic data, the images of LM, AFM, and SEM/EDX showed that after 6 h of exposure to petroleum, a passivation film was formed on the surface of the steel. This film consisted of two layers, an external one, formed of FeS, and an internal one, composed of iron oxides and oxyhydroxides. However, after 48 h of thermal degradation, this morphology was altered to a single layer of FeS coating the steel surface.

Research paper thumbnail of Corrosion rate studies of AISI 1020 steel using linear, cyclic, and aromatic naphthenic acid standards

Journal of Petroleum Science and Engineering, 2019

Research paper thumbnail of Study of degradation of acid crude oil by high resolution analytical techniques

Journal of Petroleum Science and Engineering, 2017

The extraction and refining process of unconventional oils, including heavy and extra heavy oils,... more The extraction and refining process of unconventional oils, including heavy and extra heavy oils, has been a challenge to be overcome in the petrochemical industry. These oils typically comprise polar compounds responsible for some undesirable properties, such as naphthenic acids (NAs), which can be associated with the high corrosion rates in refineries. In this context, corrosion caused by NAs is among the most aggressive ones, and it can be accentuated when in presence of other compounds usually found in oil. Herein, a heavy oil sample was subjected to thermal degradation process at 350°C aiming the understanding of its behavior at the molecular level and to evaluate its physicochemical properties as a function of degradation time. Additionally, the oil was characterized by classic and high resolution analytical techniques. The obtained results showed that the oil exposed to longer degradation times (t≥24 h) presented characteristics of "lighter" oil due to mainly disaggregation of resins and asphaltenes. Total Acid number (TAN) analysis displayed a decrease of 68.3% (from 2.0 to 0.75 mg KOH g −1) of its initial value after 36 h of degradation at 350°C. Other important changes observed included an increase in API gravity (of two decimal places from 17 to 19), and decreases in the pour point from −12 to −36°C, in the kinematic viscosity in 86.5% and of total sulfur content in 5.2% (from 0.58 to 0.55 wt%). The HTGC and NMR results showed that the saturated fraction is not affected during the thermal stress process, whereas a subtle increase in the number of aromatic compounds was observed as a function of degradation time. This behavior can be attributed to the disaggregation of resins and asphaltenes as well as to the decarboxylation process. The last process was confirmed by ESI(-)-FT-ICR MS, where a reduction of average mass molar distribution from 466 to 450 Da was observed. and naphthenate deposits (Mapolelo et al., 2011) and also are considered the main responsible for the corrosion in oil refineries (Mapolelo et al., 2011; Head et al., 2003; Rowland et al., 2014; Terra et al., 2014). Corrosion caused by naphthenic acid (NA), or naphthenic corrosion, is among the most aggressive ones and can be enhanced by the presence of other compounds commonly found in oil such as: sulfur compounds, carbon dioxide, chlorides, heavy metals and byproducts of the refining process (Dias et al., 2014). The amount of NA is usually expressed in terms of the total acid

Research paper thumbnail of Evidencing the crude oil corrosion by Raman spectroscopy, atomic force microscopy and electrospray ionization FT-ICR mass spectrometry

Research paper thumbnail of Characterization of Naphthenic Acids in Thermally Degraded Petroleum by ESI(−)-FT-ICR MS and 1H NMR after Solid-Phase Extraction and Liquid/Liquid Extraction

Energy & Fuels, 2018

Naphthenic acids (NAs), present in a typical Brazilian acid crude oil and its 34 thermal degradat... more Naphthenic acids (NAs), present in a typical Brazilian acid crude oil and its 34 thermal degradation products, were investigated using two separation methodologies: solid phase 35 extraction (SPE) and liquid-liquid extraction (LLE). Fractions produced were characterized by proton nuclear magnetic resonance spectroscopy (1 H NMR) and negative-ion mode electrospray 37 ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI(-)-FT-ICR MS). 38 Among the NAs extraction methods studied, the SPE was more efficient about LLE. Besides, the 39 ESI(-)FT-ICR MS results showed that the SPE method with eluent phase variation covered the 40 detection of a larger amplitude of NAs compounds (m/z 200-1200), reducing the occurrence of 41 ion suppression on the NAs of higher average molecular weight distribution (M w). It was possible 42 to note that the aromaticity or double bond equivalent (DBE) of these produced collective 43 fractions as well as their M w values increased as a function of the polarity of the extraction 44 system (DCM → DCM:MeOH:FA). Also, 1 H NMR analysis revealed the alkyl predominance 45 evidenced by the presence of high H β content in fractions, suggesting that the NAs compounds 46 have long and unbranched chains. The behavior of NAs species during the thermal degradation 47 process was also evaluated, and the results showed the presence of them in only five SPE extracts 48 out of six, containing different M w values (M w = 366, 417, 531, 662, and 836 Da). This suggests 49 that in the last SPE fraction (named SF 6 : m/z 700-1150; carbon number of C 52-C 72 and DBE = 0-50 15; detected only in virgin crude oil), the NAs were selectively cracked during the thermal 51 degradation process.

Research paper thumbnail of Corrosion rate studies of AISI 1020 steel using linear, cyclic, and aromatic naphthenic acid standards

Journal of Petroleum Science and Engineering, 2020

The use of total acid number (TAN) to measure the acidity of crude oil samples is a common practi... more The use of total acid number (TAN) to measure the acidity of crude oil samples is a common practice. Daily practice in petroleum refineries shows that oil with a TAN less than 0.5 mg KOH g −1 can usually have unexpected corrosive behavior. Although naphthenic corrosion has been studied for many years, its process is not entirely understood. Therefore, this study investigated the influence of linear, cyclic and aromatic NAs molecules, evaluating the effect of their concentrations, molar weight (M w), structural and electronic properties on the corrosion rate of AISI 1020 steel samples at 320°C. The type and extension of corrosion were determined by surface characterization of the sample using optical microscopy (LM), atomic force microscopy (AFM), and scanning electron microscopy (SEM). The results showed that even when TAN was below the detection limit, the corrosion rate (CR) value was significant (CR < 0.19 mm year −1) and considered high for the industry. For concentrations of benzoic (BENA) and stearic (STA) acids higher than 5000 ppm, the corrosion rate varied proportionally with the TAN. Also, there was an inverse proportional correlation between molecular weight (M w), the number of aromatic rings and NAs corrosiveness. In general, NAs standards containing a lower molar volume were found to cause a higher corrosion rate. SEM micrographs revealed changes in the surface area of all samples exposed to linear, cyclic and aromatic NAs, indicating the formation of a protective layer under the surface of the carbon steel specimen. AFM imaging showed drastic changes in the topographic profile and phase images characterized by the formation of valleys and peaks, as well as variations in the mechanical properties of the surface of the AISI 1020 steel sample. Results obtained in this study confirm the influence of the electronicstructural properties of the molecules of organic acids on the naphthenic corrosion. This observation can be confirmed by the behavior of Athabasca crude oil, which demonstrates high corrosion rates, even having low

Research paper thumbnail of De Mensen Hoodie s van Streetwear van de Manier van het Embleem van de Douane van de Prijs van de Fabriek van Hip Hop

Journal of the Brazilian Chemical Society, Aug 1, 2018

Microscopic techniques were combined to study the influence of corrosion rate on the morphologic ... more Microscopic techniques were combined to study the influence of corrosion rate on the morphologic behavior of AISI 1020 steel specimens submitted to thermal degradation of a typical acid crude oil (total acid number (TAN) = 2.1390 mg KOH g-1 and total sulfur (S) = 0.7778 wt.%). The techniques used were light microscopy (LM), scanning electron microscopy/energy dispersive spectroscopy (SEM/EDX), atomic force microscopy (AFM) as well as Raman spectroscopy. Assays were performed in six different degradation time (t = 6, 12, 24, 36, 48 and 72 h) at 320 °C. After the exposure of the specimens to petroleum, a reduction above 37% in the TAN after t = 72 h was observed, with a maximum corrosion rate during the first periods of degradation (t = 6 and 12 h). Correlating the TAN and corrosion rate data with the microscopic data, the images of LM, AFM, and SEM/EDX showed that after 6 h of exposure to petroleum, a passivation film was formed on the surface of the steel. This film consisted of two layers, an external one, formed of FeS, and an internal one, composed of iron oxides and oxyhydroxides. However, after 48 h of thermal degradation, this morphology was altered to a single layer of FeS coating the steel surface.

Research paper thumbnail of 3D Machine van de Pers van de Hitte van de Film Vacuüm met Infrarode het Verwarmen Functie (iNV-3Dpro)

Journal of the Brazilian Chemical Society, Aug 1, 2018

Microscopic techniques were combined to study the influence of corrosion rate on the morphologic ... more Microscopic techniques were combined to study the influence of corrosion rate on the morphologic behavior of AISI 1020 steel specimens submitted to thermal degradation of a typical acid crude oil (total acid number (TAN) = 2.1390 mg KOH g-1 and total sulfur (S) = 0.7778 wt.%). The techniques used were light microscopy (LM), scanning electron microscopy/energy dispersive spectroscopy (SEM/EDX), atomic force microscopy (AFM) as well as Raman spectroscopy. Assays were performed in six different degradation time (t = 6, 12, 24, 36, 48 and 72 h) at 320 °C. After the exposure of the specimens to petroleum, a reduction above 37% in the TAN after t = 72 h was observed, with a maximum corrosion rate during the first periods of degradation (t = 6 and 12 h). Correlating the TAN and corrosion rate data with the microscopic data, the images of LM, AFM, and SEM/EDX showed that after 6 h of exposure to petroleum, a passivation film was formed on the surface of the steel. This film consisted of two layers, an external one, formed of FeS, and an internal one, composed of iron oxides and oxyhydroxides. However, after 48 h of thermal degradation, this morphology was altered to a single layer of FeS coating the steel surface.

Research paper thumbnail of De in het groot Pyjama's Organische Lycra Van uitstekende kwaliteit van Kinderen voor de Kleren van de Baby

Journal of the Brazilian Chemical Society, Aug 1, 2018

Microscopic techniques were combined to study the influence of corrosion rate on the morphologic ... more Microscopic techniques were combined to study the influence of corrosion rate on the morphologic behavior of AISI 1020 steel specimens submitted to thermal degradation of a typical acid crude oil (total acid number (TAN) = 2.1390 mg KOH g-1 and total sulfur (S) = 0.7778 wt.%). The techniques used were light microscopy (LM), scanning electron microscopy/energy dispersive spectroscopy (SEM/EDX), atomic force microscopy (AFM) as well as Raman spectroscopy. Assays were performed in six different degradation time (t = 6, 12, 24, 36, 48 and 72 h) at 320 °C. After the exposure of the specimens to petroleum, a reduction above 37% in the TAN after t = 72 h was observed, with a maximum corrosion rate during the first periods of degradation (t = 6 and 12 h). Correlating the TAN and corrosion rate data with the microscopic data, the images of LM, AFM, and SEM/EDX showed that after 6 h of exposure to petroleum, a passivation film was formed on the surface of the steel. This film consisted of two layers, an external one, formed of FeS, and an internal one, composed of iron oxides and oxyhydroxides. However, after 48 h of thermal degradation, this morphology was altered to a single layer of FeS coating the steel surface.

Research paper thumbnail of Hoge Efficiency van het Zonne paneel van 325 Watts Poly CEI- Ce- Certificaat

Journal of the Brazilian Chemical Society, Aug 1, 2018

Microscopic techniques were combined to study the influence of corrosion rate on the morphologic ... more Microscopic techniques were combined to study the influence of corrosion rate on the morphologic behavior of AISI 1020 steel specimens submitted to thermal degradation of a typical acid crude oil (total acid number (TAN) = 2.1390 mg KOH g-1 and total sulfur (S) = 0.7778 wt.%). The techniques used were light microscopy (LM), scanning electron microscopy/energy dispersive spectroscopy (SEM/EDX), atomic force microscopy (AFM) as well as Raman spectroscopy. Assays were performed in six different degradation time (t = 6, 12, 24, 36, 48 and 72 h) at 320 °C. After the exposure of the specimens to petroleum, a reduction above 37% in the TAN after t = 72 h was observed, with a maximum corrosion rate during the first periods of degradation (t = 6 and 12 h). Correlating the TAN and corrosion rate data with the microscopic data, the images of LM, AFM, and SEM/EDX showed that after 6 h of exposure to petroleum, a passivation film was formed on the surface of the steel. This film consisted of two layers, an external one, formed of FeS, and an internal one, composed of iron oxides and oxyhydroxides. However, after 48 h of thermal degradation, this morphology was altered to a single layer of FeS coating the steel surface.

Research paper thumbnail of De Delen van de Opschorting van de auto voor AutomobielDelen

Journal of the Brazilian Chemical Society, Aug 1, 2018

Microscopic techniques were combined to study the influence of corrosion rate on the morphologic ... more Microscopic techniques were combined to study the influence of corrosion rate on the morphologic behavior of AISI 1020 steel specimens submitted to thermal degradation of a typical acid crude oil (total acid number (TAN) = 2.1390 mg KOH g-1 and total sulfur (S) = 0.7778 wt.%). The techniques used were light microscopy (LM), scanning electron microscopy/energy dispersive spectroscopy (SEM/EDX), atomic force microscopy (AFM) as well as Raman spectroscopy. Assays were performed in six different degradation time (t = 6, 12, 24, 36, 48 and 72 h) at 320 °C. After the exposure of the specimens to petroleum, a reduction above 37% in the TAN after t = 72 h was observed, with a maximum corrosion rate during the first periods of degradation (t = 6 and 12 h). Correlating the TAN and corrosion rate data with the microscopic data, the images of LM, AFM, and SEM/EDX showed that after 6 h of exposure to petroleum, a passivation film was formed on the surface of the steel. This film consisted of two layers, an external one, formed of FeS, and an internal one, composed of iron oxides and oxyhydroxides. However, after 48 h of thermal degradation, this morphology was altered to a single layer of FeS coating the steel surface.

Research paper thumbnail of Y83-500 de Pers van het Briketteren van de Schroot

Journal of the Brazilian Chemical Society, Aug 1, 2018

Microscopic techniques were combined to study the influence of corrosion rate on the morphologic ... more Microscopic techniques were combined to study the influence of corrosion rate on the morphologic behavior of AISI 1020 steel specimens submitted to thermal degradation of a typical acid crude oil (total acid number (TAN) = 2.1390 mg KOH g-1 and total sulfur (S) = 0.7778 wt.%). The techniques used were light microscopy (LM), scanning electron microscopy/energy dispersive spectroscopy (SEM/EDX), atomic force microscopy (AFM) as well as Raman spectroscopy. Assays were performed in six different degradation time (t = 6, 12, 24, 36, 48 and 72 h) at 320 °C. After the exposure of the specimens to petroleum, a reduction above 37% in the TAN after t = 72 h was observed, with a maximum corrosion rate during the first periods of degradation (t = 6 and 12 h). Correlating the TAN and corrosion rate data with the microscopic data, the images of LM, AFM, and SEM/EDX showed that after 6 h of exposure to petroleum, a passivation film was formed on the surface of the steel. This film consisted of two layers, an external one, formed of FeS, and an internal one, composed of iron oxides and oxyhydroxides. However, after 48 h of thermal degradation, this morphology was altered to a single layer of FeS coating the steel surface.

Research paper thumbnail of De Machine van de Pers van de Hitte van GLB

Journal of the Brazilian Chemical Society, Aug 1, 2018

Microscopic techniques were combined to study the influence of corrosion rate on the morphologic ... more Microscopic techniques were combined to study the influence of corrosion rate on the morphologic behavior of AISI 1020 steel specimens submitted to thermal degradation of a typical acid crude oil (total acid number (TAN) = 2.1390 mg KOH g-1 and total sulfur (S) = 0.7778 wt.%). The techniques used were light microscopy (LM), scanning electron microscopy/energy dispersive spectroscopy (SEM/EDX), atomic force microscopy (AFM) as well as Raman spectroscopy. Assays were performed in six different degradation time (t = 6, 12, 24, 36, 48 and 72 h) at 320 °C. After the exposure of the specimens to petroleum, a reduction above 37% in the TAN after t = 72 h was observed, with a maximum corrosion rate during the first periods of degradation (t = 6 and 12 h). Correlating the TAN and corrosion rate data with the microscopic data, the images of LM, AFM, and SEM/EDX showed that after 6 h of exposure to petroleum, a passivation film was formed on the surface of the steel. This film consisted of two layers, an external one, formed of FeS, and an internal one, composed of iron oxides and oxyhydroxides. However, after 48 h of thermal degradation, this morphology was altered to a single layer of FeS coating the steel surface.

Research paper thumbnail of 2400mAh reusachtige Capaciteit Ecigarette DNA30

Journal of the Brazilian Chemical Society, Aug 1, 2018

Microscopic techniques were combined to study the influence of corrosion rate on the morphologic ... more Microscopic techniques were combined to study the influence of corrosion rate on the morphologic behavior of AISI 1020 steel specimens submitted to thermal degradation of a typical acid crude oil (total acid number (TAN) = 2.1390 mg KOH g-1 and total sulfur (S) = 0.7778 wt.%). The techniques used were light microscopy (LM), scanning electron microscopy/energy dispersive spectroscopy (SEM/EDX), atomic force microscopy (AFM) as well as Raman spectroscopy. Assays were performed in six different degradation time (t = 6, 12, 24, 36, 48 and 72 h) at 320 °C. After the exposure of the specimens to petroleum, a reduction above 37% in the TAN after t = 72 h was observed, with a maximum corrosion rate during the first periods of degradation (t = 6 and 12 h). Correlating the TAN and corrosion rate data with the microscopic data, the images of LM, AFM, and SEM/EDX showed that after 6 h of exposure to petroleum, a passivation film was formed on the surface of the steel. This film consisted of two layers, an external one, formed of FeS, and an internal one, composed of iron oxides and oxyhydroxides. However, after 48 h of thermal degradation, this morphology was altered to a single layer of FeS coating the steel surface.

Research paper thumbnail of De in het groot van de Katoenen van 100% Nieuwe Kleding Jonge geitjes van de Douane - de geboren Kleren van de Baby

Journal of the Brazilian Chemical Society, Aug 1, 2018

Microscopic techniques were combined to study the influence of corrosion rate on the morphologic ... more Microscopic techniques were combined to study the influence of corrosion rate on the morphologic behavior of AISI 1020 steel specimens submitted to thermal degradation of a typical acid crude oil (total acid number (TAN) = 2.1390 mg KOH g-1 and total sulfur (S) = 0.7778 wt.%). The techniques used were light microscopy (LM), scanning electron microscopy/energy dispersive spectroscopy (SEM/EDX), atomic force microscopy (AFM) as well as Raman spectroscopy. Assays were performed in six different degradation time (t = 6, 12, 24, 36, 48 and 72 h) at 320 °C. After the exposure of the specimens to petroleum, a reduction above 37% in the TAN after t = 72 h was observed, with a maximum corrosion rate during the first periods of degradation (t = 6 and 12 h). Correlating the TAN and corrosion rate data with the microscopic data, the images of LM, AFM, and SEM/EDX showed that after 6 h of exposure to petroleum, a passivation film was formed on the surface of the steel. This film consisted of two layers, an external one, formed of FeS, and an internal one, composed of iron oxides and oxyhydroxides. However, after 48 h of thermal degradation, this morphology was altered to a single layer of FeS coating the steel surface.

Research paper thumbnail of 5000W Toroidal Transformator van de Kern 5000va van de ring

Journal of the Brazilian Chemical Society, Aug 1, 2018

Microscopic techniques were combined to study the influence of corrosion rate on the morphologic ... more Microscopic techniques were combined to study the influence of corrosion rate on the morphologic behavior of AISI 1020 steel specimens submitted to thermal degradation of a typical acid crude oil (total acid number (TAN) = 2.1390 mg KOH g-1 and total sulfur (S) = 0.7778 wt.%). The techniques used were light microscopy (LM), scanning electron microscopy/energy dispersive spectroscopy (SEM/EDX), atomic force microscopy (AFM) as well as Raman spectroscopy. Assays were performed in six different degradation time (t = 6, 12, 24, 36, 48 and 72 h) at 320 °C. After the exposure of the specimens to petroleum, a reduction above 37% in the TAN after t = 72 h was observed, with a maximum corrosion rate during the first periods of degradation (t = 6 and 12 h). Correlating the TAN and corrosion rate data with the microscopic data, the images of LM, AFM, and SEM/EDX showed that after 6 h of exposure to petroleum, a passivation film was formed on the surface of the steel. This film consisted of two layers, an external one, formed of FeS, and an internal one, composed of iron oxides and oxyhydroxides. However, after 48 h of thermal degradation, this morphology was altered to a single layer of FeS coating the steel surface.

Research paper thumbnail of 1350W 4-kanaals versterker voor Stage-luidspreker

Journal of the Brazilian Chemical Society, Aug 1, 2018

Microscopic techniques were combined to study the influence of corrosion rate on the morphologic ... more Microscopic techniques were combined to study the influence of corrosion rate on the morphologic behavior of AISI 1020 steel specimens submitted to thermal degradation of a typical acid crude oil (total acid number (TAN) = 2.1390 mg KOH g-1 and total sulfur (S) = 0.7778 wt.%). The techniques used were light microscopy (LM), scanning electron microscopy/energy dispersive spectroscopy (SEM/EDX), atomic force microscopy (AFM) as well as Raman spectroscopy. Assays were performed in six different degradation time (t = 6, 12, 24, 36, 48 and 72 h) at 320 °C. After the exposure of the specimens to petroleum, a reduction above 37% in the TAN after t = 72 h was observed, with a maximum corrosion rate during the first periods of degradation (t = 6 and 12 h). Correlating the TAN and corrosion rate data with the microscopic data, the images of LM, AFM, and SEM/EDX showed that after 6 h of exposure to petroleum, a passivation film was formed on the surface of the steel. This film consisted of two layers, an external one, formed of FeS, and an internal one, composed of iron oxides and oxyhydroxides. However, after 48 h of thermal degradation, this morphology was altered to a single layer of FeS coating the steel surface.

Research paper thumbnail of Haak Steel304/316 van de Hardware van het optuigen de Roestvrije van Bevestigingsmiddel

Journal of the Brazilian Chemical Society, Aug 1, 2018

Microscopic techniques were combined to study the influence of corrosion rate on the morphologic ... more Microscopic techniques were combined to study the influence of corrosion rate on the morphologic behavior of AISI 1020 steel specimens submitted to thermal degradation of a typical acid crude oil (total acid number (TAN) = 2.1390 mg KOH g-1 and total sulfur (S) = 0.7778 wt.%). The techniques used were light microscopy (LM), scanning electron microscopy/energy dispersive spectroscopy (SEM/EDX), atomic force microscopy (AFM) as well as Raman spectroscopy. Assays were performed in six different degradation time (t = 6, 12, 24, 36, 48 and 72 h) at 320 °C. After the exposure of the specimens to petroleum, a reduction above 37% in the TAN after t = 72 h was observed, with a maximum corrosion rate during the first periods of degradation (t = 6 and 12 h). Correlating the TAN and corrosion rate data with the microscopic data, the images of LM, AFM, and SEM/EDX showed that after 6 h of exposure to petroleum, a passivation film was formed on the surface of the steel. This film consisted of two layers, an external one, formed of FeS, and an internal one, composed of iron oxides and oxyhydroxides. However, after 48 h of thermal degradation, this morphology was altered to a single layer of FeS coating the steel surface.

Research paper thumbnail of Hete het Verkopen Druk 100% Kleren van de Baby van het Katoenen Proces van het Kamgaren Pasgeboren

Journal of the Brazilian Chemical Society, Aug 1, 2018

Microscopic techniques were combined to study the influence of corrosion rate on the morphologic ... more Microscopic techniques were combined to study the influence of corrosion rate on the morphologic behavior of AISI 1020 steel specimens submitted to thermal degradation of a typical acid crude oil (total acid number (TAN) = 2.1390 mg KOH g-1 and total sulfur (S) = 0.7778 wt.%). The techniques used were light microscopy (LM), scanning electron microscopy/energy dispersive spectroscopy (SEM/EDX), atomic force microscopy (AFM) as well as Raman spectroscopy. Assays were performed in six different degradation time (t = 6, 12, 24, 36, 48 and 72 h) at 320 °C. After the exposure of the specimens to petroleum, a reduction above 37% in the TAN after t = 72 h was observed, with a maximum corrosion rate during the first periods of degradation (t = 6 and 12 h). Correlating the TAN and corrosion rate data with the microscopic data, the images of LM, AFM, and SEM/EDX showed that after 6 h of exposure to petroleum, a passivation film was formed on the surface of the steel. This film consisted of two layers, an external one, formed of FeS, and an internal one, composed of iron oxides and oxyhydroxides. However, after 48 h of thermal degradation, this morphology was altered to a single layer of FeS coating the steel surface.

Research paper thumbnail of De Catheter van de Ballon van Kyphoplasty

Journal of the Brazilian Chemical Society, Aug 1, 2018

Microscopic techniques were combined to study the influence of corrosion rate on the morphologic ... more Microscopic techniques were combined to study the influence of corrosion rate on the morphologic behavior of AISI 1020 steel specimens submitted to thermal degradation of a typical acid crude oil (total acid number (TAN) = 2.1390 mg KOH g-1 and total sulfur (S) = 0.7778 wt.%). The techniques used were light microscopy (LM), scanning electron microscopy/energy dispersive spectroscopy (SEM/EDX), atomic force microscopy (AFM) as well as Raman spectroscopy. Assays were performed in six different degradation time (t = 6, 12, 24, 36, 48 and 72 h) at 320 °C. After the exposure of the specimens to petroleum, a reduction above 37% in the TAN after t = 72 h was observed, with a maximum corrosion rate during the first periods of degradation (t = 6 and 12 h). Correlating the TAN and corrosion rate data with the microscopic data, the images of LM, AFM, and SEM/EDX showed that after 6 h of exposure to petroleum, a passivation film was formed on the surface of the steel. This film consisted of two layers, an external one, formed of FeS, and an internal one, composed of iron oxides and oxyhydroxides. However, after 48 h of thermal degradation, this morphology was altered to a single layer of FeS coating the steel surface.

Research paper thumbnail of Study of the Corrosive Behavior of the AISI 1020 Steel in Acid Crude Oil by Microscopic Techniques (LM, AFM and SEM/EDX) and Raman Spectroscopy

Journal of the Brazilian Chemical Society, 2018

Microscopic techniques were combined to study the influence of corrosion rate on the morphologic ... more Microscopic techniques were combined to study the influence of corrosion rate on the morphologic behavior of AISI 1020 steel specimens submitted to thermal degradation of a typical acid crude oil (total acid number (TAN) = 2.1390 mg KOH g-1 and total sulfur (S) = 0.7778 wt.%). The techniques used were light microscopy (LM), scanning electron microscopy/energy dispersive spectroscopy (SEM/EDX), atomic force microscopy (AFM) as well as Raman spectroscopy. Assays were performed in six different degradation time (t = 6, 12, 24, 36, 48 and 72 h) at 320 °C. After the exposure of the specimens to petroleum, a reduction above 37% in the TAN after t = 72 h was observed, with a maximum corrosion rate during the first periods of degradation (t = 6 and 12 h). Correlating the TAN and corrosion rate data with the microscopic data, the images of LM, AFM, and SEM/EDX showed that after 6 h of exposure to petroleum, a passivation film was formed on the surface of the steel. This film consisted of two layers, an external one, formed of FeS, and an internal one, composed of iron oxides and oxyhydroxides. However, after 48 h of thermal degradation, this morphology was altered to a single layer of FeS coating the steel surface.

Research paper thumbnail of Corrosion rate studies of AISI 1020 steel using linear, cyclic, and aromatic naphthenic acid standards

Journal of Petroleum Science and Engineering, 2019

Research paper thumbnail of Study of degradation of acid crude oil by high resolution analytical techniques

Journal of Petroleum Science and Engineering, 2017

The extraction and refining process of unconventional oils, including heavy and extra heavy oils,... more The extraction and refining process of unconventional oils, including heavy and extra heavy oils, has been a challenge to be overcome in the petrochemical industry. These oils typically comprise polar compounds responsible for some undesirable properties, such as naphthenic acids (NAs), which can be associated with the high corrosion rates in refineries. In this context, corrosion caused by NAs is among the most aggressive ones, and it can be accentuated when in presence of other compounds usually found in oil. Herein, a heavy oil sample was subjected to thermal degradation process at 350°C aiming the understanding of its behavior at the molecular level and to evaluate its physicochemical properties as a function of degradation time. Additionally, the oil was characterized by classic and high resolution analytical techniques. The obtained results showed that the oil exposed to longer degradation times (t≥24 h) presented characteristics of "lighter" oil due to mainly disaggregation of resins and asphaltenes. Total Acid number (TAN) analysis displayed a decrease of 68.3% (from 2.0 to 0.75 mg KOH g −1) of its initial value after 36 h of degradation at 350°C. Other important changes observed included an increase in API gravity (of two decimal places from 17 to 19), and decreases in the pour point from −12 to −36°C, in the kinematic viscosity in 86.5% and of total sulfur content in 5.2% (from 0.58 to 0.55 wt%). The HTGC and NMR results showed that the saturated fraction is not affected during the thermal stress process, whereas a subtle increase in the number of aromatic compounds was observed as a function of degradation time. This behavior can be attributed to the disaggregation of resins and asphaltenes as well as to the decarboxylation process. The last process was confirmed by ESI(-)-FT-ICR MS, where a reduction of average mass molar distribution from 466 to 450 Da was observed. and naphthenate deposits (Mapolelo et al., 2011) and also are considered the main responsible for the corrosion in oil refineries (Mapolelo et al., 2011; Head et al., 2003; Rowland et al., 2014; Terra et al., 2014). Corrosion caused by naphthenic acid (NA), or naphthenic corrosion, is among the most aggressive ones and can be enhanced by the presence of other compounds commonly found in oil such as: sulfur compounds, carbon dioxide, chlorides, heavy metals and byproducts of the refining process (Dias et al., 2014). The amount of NA is usually expressed in terms of the total acid

Research paper thumbnail of Evidencing the crude oil corrosion by Raman spectroscopy, atomic force microscopy and electrospray ionization FT-ICR mass spectrometry

Research paper thumbnail of Characterization of Naphthenic Acids in Thermally Degraded Petroleum by ESI(−)-FT-ICR MS and 1H NMR after Solid-Phase Extraction and Liquid/Liquid Extraction

Energy & Fuels, 2018

Naphthenic acids (NAs), present in a typical Brazilian acid crude oil and its 34 thermal degradat... more Naphthenic acids (NAs), present in a typical Brazilian acid crude oil and its 34 thermal degradation products, were investigated using two separation methodologies: solid phase 35 extraction (SPE) and liquid-liquid extraction (LLE). Fractions produced were characterized by proton nuclear magnetic resonance spectroscopy (1 H NMR) and negative-ion mode electrospray 37 ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI(-)-FT-ICR MS). 38 Among the NAs extraction methods studied, the SPE was more efficient about LLE. Besides, the 39 ESI(-)FT-ICR MS results showed that the SPE method with eluent phase variation covered the 40 detection of a larger amplitude of NAs compounds (m/z 200-1200), reducing the occurrence of 41 ion suppression on the NAs of higher average molecular weight distribution (M w). It was possible 42 to note that the aromaticity or double bond equivalent (DBE) of these produced collective 43 fractions as well as their M w values increased as a function of the polarity of the extraction 44 system (DCM → DCM:MeOH:FA). Also, 1 H NMR analysis revealed the alkyl predominance 45 evidenced by the presence of high H β content in fractions, suggesting that the NAs compounds 46 have long and unbranched chains. The behavior of NAs species during the thermal degradation 47 process was also evaluated, and the results showed the presence of them in only five SPE extracts 48 out of six, containing different M w values (M w = 366, 417, 531, 662, and 836 Da). This suggests 49 that in the last SPE fraction (named SF 6 : m/z 700-1150; carbon number of C 52-C 72 and DBE = 0-50 15; detected only in virgin crude oil), the NAs were selectively cracked during the thermal 51 degradation process.