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A. Al-hajji – One of the best experts on this subject based on the ideXlab platform.

  • Role of Naphthenic Acids in Emulsion Tightness for a Low-Total-AcidNumber (TAN)/High-Asphaltenes Oil†
    Energy & Fuels, 2009
    Co-Authors: V. Pauchard, J. SjÖblom, S. Kokal, Patrick Bouriat, Christophe Dicharry, H. Muller, A. Al-hajji
    Abstract:

    The emulsion stabilizing properties of a low-total-AcidNumber (TAN) crude oil, which had initially been attributed to asphaltenes and calcite precipitation, were re-analyzed with regard to the role of organic Acids. Despite high asphaltenes content, this crude oil exhibits features classically observed with Acidic oils, such as the increase in emulsion stability upon pressure decrease/pH increase or the poor efficiency of demulsifiers. The potential for a significant role of organic Acids was confirmed by the high interfacial activity of indigenous Acids, as extracted from the crude oil by means of an ion-exchange resin. This was further addressed analyzing the molecular chemistry of the interfacial layer and its rheology. The interfacial material was found to be composed of a mixture of asphaltenes and organic Acids. These Acids exhibit a wide range of structures (monoversus dicarboxylic, fatty versus naphthenic and benzoic) and molecular weights (from 200 to 700 g/mol), contrary to the medium molecular weight fatty monocarboxylic Acids that are generally believed to cause “soap emulsions”. The interfacial rheology is indicative of a 2D gel, with an assumed glass transition temperature of approximately 40 °C. In conclusion, this study shows that a co-precipitation of asphaltenes and organic Acids can promote the build up of a very cohesive interface. The disruption of this interface not only requires the drainage of individual molecules but also a collective yield of the gel. This paper is part one of two: it confronts physical and chemical data, the latter being further detailed in an associated paper.

  • Role of naphthenic Acids in emulsion tightness for a low total Acid Number (TAN) / high asphaltene oil
    Energy and Fuels, 2009
    Co-Authors: V. Pauchard, J. SjÖblom, S. Kokal, Patrick Bouriat, Christophe Dicharry, H. Muller, A. Al-hajji
    Abstract:

    The emulsion stabilizing properties of a low-total-AcidNumber (TAN) crude oil, which had initially been attributed to asphaltenes and calcite precipitation, were re-analyzed with regard to the role of organic Acids. Despite high asphaltenes content, this crude oil exhibits features classically observed with Acidic oils, such as the increase in emulsion stability upon pressure decrease/pH increase or the poor efficiency of demulsifiers. The potential for a significant role of organic Acids was confirmed by the high interfacial activity of indigenous Acids, as extracted from the crude oil by means of an ion-exchange resin. This was further addressed analyzing the molecular chemistry of the interfacial layer and its rheology. The interfacial material was found to be composed of a mixture of asphaltenes and organic Acids. These Acids exhibit a wide range of structures (monoversus dicarboxylic, fatty versus naphthenic and benzoic) and molecular weights (from 200 to 700 g/mol), contrary to the medium molecular weight fatty monocarboxylic Acids that are generally believed to cause “soap emulsions”. The interfacial rheology is indicative of a 2D gel, with an assumed glass transition temperature of approximately 40 °C. In conclusion, this study shows that a co-precipitation of asphaltenes and organic Acids can promote the build up of a very cohesive interface. The disruption of this interface not only requires the drainage of individual molecules but also a collective yield of the gel. This paper is part one of two: it confronts physical and chemical data, the latter being further detailed in an associated paper.

Pradip Chandra Mandal – One of the best experts on this subject based on the ideXlab platform.

  • Kinetics and reaction pathways of total Acid Number reduction of cyclopentane carboxylic Acid using subcritical methanol
    Polish Journal of Chemical Technology, 2016
    Co-Authors: Pradip Chandra Mandal, Thasvinya Nagarajan
    Abstract:

    Abstract Cyclopentane carboxylic Acid (CPCA) is a model compound of Naphthenic Acids (NAs). This objective of this paper is to discover total Acid Number (TAN) reduction kinetics and pathways of the reaction between CAPA and subcritical methanol (SubC-MeOH). The experiments were carried out in an autoclave reactor at temperatures of 180-220°C, a methanol partial pressure (MPP) of 3 MPa, reaction times of 0-30 min and CPCA initial gas phase concentrations of 0.016-0.04 g/mL. TAN content of the samples were analyzed using ASTM D 974 techniques. The reaction products were identified and quantified with the help of GC/MS and GC-FID respectively. Experimental results reveal that TAN removal kinetics followed first order kinetics with an activation energy of 13.97 kcal/mol and a pre-exponential factor of 174.21 s-1. Subcritical methanol is able to reduce TAN of CPCA decomposing CPCA into new compounds such as cyclopentane, formaldehyde, methyl acetate and 3-pentanol.

  • Total Acid Number Reduction of Naphthenic Acid Using Subcritical Methanol and 1-Butyl-3-Methylimidazolium Octylsulfate
    Procedia Engineering, 2016
    Co-Authors: Faisal Zafar, Pradip Chandra Mandal, Ku Zilati Ku Shaari, Muhammad Moniruzzaman
    Abstract:

    AbstractNaphthenic Acids (NAs) are naturally occurring organic Acids present in crude oil and bitumen as contaminants. Their presence in the crude oil greatly reduces the quality and price of crude oil. NAs also causes corrosion in the production and processing facilities. They are quantified in the petroleum as Total Acid Number (TAN), which is the amount of KOH required to neutralize one gram of oil. In this study, the TAN of NAs was reduced by using subcritical methanol and then a mixture of 1-butyl-3methylimidazolium octyl sulfate ([BMIM] [C8HSO4]) and subcritical methanol. The experiments were conducted in an autoclave batch reactor at temperatures of 70-150°C, methanol partial pressures of 0.2-2.5MPa and reaction time of 0-120min. TAN value of the reaction was analyzed by ASTM D974 method. The experimental results demonstrate that high temperature and reaction time favors the TAN reduction. Approximately 24% TAN reduction was achieved by using only subcritical methanol at a temperature of 150°C, methanol partial pressure of 0.2MPa and reaction time of 30min. TAN was reduced to 32% by the addition of [BMIM] [C8HSO4] at the same conditions, indicating the capability of this IL to work under the subcritical methanol conditions. Maximum 56% TAN reduction was achieved at a temperature of 150°C, a reaction time of 120min using subcritical methanol. These results show that the subcritical methanol has the ability to lower the reaction time in an environmental-friendly and economical way. The presence of 1-butyl-3-methylimidazolium octyl sulfate [BMIM] [C8HSO4] further help in lowering the TAN

  • Total Acid Number Reduction of 2, 6-Naphthalenedicarboxylic Acid Using Subcritical Methanol for Reducing Acidity of Heavy Oil: A Kinetic Study
    Procedia Engineering, 2016
    Co-Authors: Pradip Chandra Mandal, Anuar Bin Abdullah, Mohamed Mahbubur Rahman
    Abstract:

    AbstractNaphthenic Acid (NA) found in hydrocarbon deposits is responsible for Acidity of petroleum oils. In this study, a model compound of NAs, 2, 6-Naphthalenedicarboxylic Acid (NDCA), is used for total Acid Number (TAN) reduction kinetic analysis. This goal of this paper is to investigate the capability of subcritical methanol (SubC-MeOH) for reducing Acidity of NDCA without the addition of any catalyst or additives. The reaction kinetics is also discovered for large scale reactor design. The experiments were carried out in a 25 ml autoclave reactor (China) at temperatures of 180-220oC, a methanol partial pressure (MPP) of 0.1 MPa, reaction times of 0-60 min and a NDCA initial gas phase concentration of 0.03 g/mL. The TAN content of the samples were analyzed using American Society for Testing Materials (ASTM) D 974 techniques. The reaction products were identified and quantified with the help of GC/MS and GC-FID respectively. Experimental results reveal that TAN reduction of NDCA was increasing with increasing reaction temperature and time. Approximately, 52.12% TAN was reduced at a temperature of 220oC, a MPP of 0.1 MPa, and a reaction time of 60 min. Experimental data revealed that TAN removal reaction kinetics followed second order kinetics with an activation energy of 8.24 kcal/mol and a pre-exponential factor of 2.087 fraction-1s-1. Therefore, SubC-MeOH is capable to reduce TAN of NDCA without the addition of any catalyst or additives

Motonobu Goto – One of the best experts on this subject based on the ideXlab platform.

  • non catalytic reduction of total Acid Number tan of naphthenic Acids nas using supercritical methanol
    Fuel Processing Technology, 2013
    Co-Authors: Pradip Chandra Mandal, Mitsuru Sasaki, Motonobu Goto
    Abstract:

    Abstract Naphthenic Acid (NA) present in crude oil leads to corrosion problems within oil refineries. The objective of this study is to reduce total Acid Number (TAN) from NA using a catalyst-free supercritical methanol (SC-MeOH), a process novel in this area. The reaction was carried out in an 8.8 mL batch reactor fabricated from Hastelloy C-276 with respective design temperature and pressure of 500 °C and 50 MPa. The ability of SC-MeOH to reduce TAN was explored at temperatures from 300 to 350 °C and methanol partial pressure (MPP) of 10 MPa. Experimental results revealed that TAN removal was 99.77% at a temperature of 350 °C, MPP of 10 MPa and reaction time of 60 min. The TAN removal followed first order kinetics, with Arrhenius parameters of activation energy 5.78 kcal/ mol and a pre-exponential factor 1.56 s − 1 . These results suggest that SC-MeOH is capable of reducing TAN from NA with no use of catalyst or additives.

  • Reduction of total Acid Number (TAN) of naphthenic Acid (NA) using supercritical water for reducing corrosion problems of oil refineries
    Fuel, 2012
    Co-Authors: Pradip Chandra Mandal, Mitsuru Sasaki, Wahyudiono, Motonobu Goto
    Abstract:

    Abstract Naphthenic Acid (NA) are present in crude oil and lead to corrosion problems within the oil refineries. The objective of this study is to reduce total Acid Number (TAN) from NA in an environmentally benign way, suppressing the solid deposition using supercritical water (SCW). The reaction was carried out in an 8.8 mL batch reactor fabricated from Hastelloy C-276 with respective design temperature and pressure of 500 °C and 50 MPa. The ability of SCW to reduce TAN was explored at temperatures from 400 to 490 °C and water partial pressures (WPPs) from 0 to 45 MPa. Experimental results revealed that TAN removal was 83% at a temperature of 490 °C, WPP of 45 MPa and reaction time of 90 min. The TAN removal followed first order kinetics, with Arrhenius parameters of activation energy 66 ± 4 kJ/mol and a pre-exponential factor (1.4 ± 0.2) × 10 5  s −1 . Solid deposition was drastically reduced at WPP of 45 MPa. These results suggest that SCW is capable of reduction of TAN from NA with no use of catalyst or additives.