Naphthenic acids, total acid number and sulfur content profile characterization in Isthmus and Maya crude oils

Laredo, Georgina C.; López, Carla R.; Alvarez, Regina; Cano, José L.

doi:10.1016/j.fuel.2004.02.004

Cited by 83 publications

(68 citation statements)

References 11 publications

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“…25,80,81 A corrosão nas unidades de destilação da refinaria Salina Cruz (México), tanto à pressão atmosférica, quanto à pressão reduzida, foi estudada por Laredo e colaboradores. 82 De acordo com os resultados, a presença de ácidos naftênicos de baixo peso molecular, associada ao . O precipitado, com a maioria dos ácidos naftênicos, foi removido com DCM.…”

Section: Relação Entre O Teor De Enxofre No Combustível E a Corrosão unclassified

Ácidos naftênicos no petróleo

Gruber¹,

Damasceno²,

Caramão³

et al. 2012

Quím. Nova

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Recebido em 22/7/11; aceito em 5/2/12; publicado na web em 15/5/12 NAPHTHENIC ACIDS IN PETROLEUM. Brazilian petroleum is known by its high acidity due to the presence of acidic constituents, especially naphthenic acids (NA). The total characterization of the NA in petrochemical samples has been receiving special attention in research and comprises an analytical challenge, mainly due to the complexity of their mixtures. Gas chromatography with mass detector (GC/MS) is the technique of analysis more used, but recently comprehensive two-dimensional gas chromatography (GC × GC) has been used, due to its high resolution, peak capacity and sensitivity. The goal of this article is to discuss the techniques for sample preparation and analysis of NA in petroleum.Keywords: petrochemicals samples; naphthenic acids; characterization of the NA. INTRODUÇÃONos últimos anos grande parte das reservas de petróleo descobertas em território brasileiro consiste de óleo pesado de baixo grau API (<20º), alta viscosidade e elevada acidez total. 1 A Empresa de Petróleo Brasileiro S/A, PETROBRAS, visando viabilizar a comercialização do petróleo vem investindo em programas de pesquisa e desenvolvimento, tais como, PRAVAP (Programa de Recuperação Avançada de Petróleo), PROTER (Programa de Tecnologias Estratégicas de Refino) e PROPES (Programa Tecnológico de Óleos Pesados).As fontes de óleo cru na América do Sul, incluindo o petróleo brasileiro, estão entre as mais ácidas do mundo.2,3 Tal acidez é responsabilizada por muitas dificuldades na utilização desta matéria-prima nas refinarias e no aproveitamento de seus resíduos.Os ácidos naftênicos (AN) são encontrados, predominantemente, em óleos imaturos, biodegradados, em óleos pesados e águas residuá-rias geradas no processo de extração do betume.4,5 Sua importância é salientada em geoquímica, aplicações comerciais, aspectos ambientais e corrosão. [2][3][4][5][6] O termo naftênico, correspondente a compostos cíclicos saturados, é usado para todos os tipos de ácidos encontrados em petróleos, mesmo os saturados lineares e os ramificados. 2,5,7 Os ácidos carboxílicos presentes no petróleo representam um grande problema para o refino e craqueamento do mesmo, devido ao seu efeito corrosivo em linhas de transferência de massa e calor, nas seções de entrada e refluxo de colunas (à pressão atmosférica e a vácuo) e nos condensadores das unidades de destilação das refinarias. 5 De forma geral, determina-se o teor de ácidos através da titulação com KOH, obtendo-se então o índice ou número de acidez naftênica. Este índice pode ser indicativo de atividade corrosiva da amostra, contudo, nada acrescenta quanto à qualidade do petróleo e à natureza dos ácidos presentes. Para caracterizar estes ácidos, é necessário extraí-los e analisá-los de forma individual. 2,5 O petróleo é constituído de uma mistura complexa de hidrocarbonetos com quantidade bastante significativa de isômeros, além destes, apresenta compostos contendo nitrogênio, oxigênio e enxofre, que dificultam as etapas de extração, isolamento e caract...

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Section: Relação Entre O Teor De Enxofre No Combustível E a Corrosão unclassified

Ácidos naftênicos no petróleo

Gruber¹,

Damasceno²,

Caramão³

et al. 2012

Quím. Nova

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“…The naphthenic acidity and the degree of corrosivity of the petroleum are usually evaluated by the total acid number (TAN) measurements, which corresponds to the amount of KOH (in mg) required to neutralize 1 g of petroleum or its fraction. 7,8 A corrosion mechanism is proposed by equations 1, 2 and 3, in which the iron naphthenate is one of the corrosion products, being soluble in the crude oil, and thus, cannot protect against a continue corrosive process (equation 1). The naphthenic corrosion can also be associated with the H 2 S (equations 2 and 3), which is responsible for the reconstitution of naphthenic acids, due to its attack on the iron naphthenate, turning the process autocatalytic (equation 3).…”

Section: Introductionmentioning

confidence: 99%

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

Dias¹,

Barros²,

Sad³

et al. 2018

J. Braz. Chem. Soc.

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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.

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“…Based on the operating experience, 5Cr0.5Mo low alloy steel is believed to be more resistant to high temperature corrosion than carbon steel, especially under flowing conditions [7]. However, some laboratory tests and field observation showed that increasing the Cr content of the steel did not appear to have significant benefits in terms of resistance to NAC [8]. Therefore, the effect of relevant alloying elements in steel is still needed to be clarified.…”

Section: Introductionmentioning

confidence: 99%

Corrosion behavior of 5Cr0.5Mo steel in sulfur-bearing solution at high temperature

Qin

Liu

Mao

et al. 2015

Mat.-wiss. u. Werkstofftech

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Corrosion behavior of 5Cr0.5Mo steel in sulfur-bearing solutions as a function of temperature, test time, and sulfur content was investigated by weight loss measurements in this study. The results indicate that the corrosion rate of the steel increases with increasing test temperature. Besides, the corrosion rate increases during the initial test time and then decreases with longer test duration. Moreover, the corrosion rate rises with a higher amount of sulfur in the solution, and consequently a lower amount of sulfur leads to a decreased corrosion rate. In addition, the effect of Cr and Mo elements has been discussed.

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Naphthenic acids, total acid number and sulfur content profile characterization in Isthmus and Maya crude oils

Cited by 83 publications

References 11 publications

Ácidos naftênicos no petróleo

Ácidos naftênicos no petróleo

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

Corrosion behavior of 5Cr0.5Mo steel in sulfur-bearing solution at high temperature

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