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Naphthenate The soap-like solids
Published in Jon Steinar Gudmundsson, Flow Assurance Solids in Oil and Gas Production, 2017
The severity of naphthene problems can be gauged by measuring the acidity of crude oils. The acidity results from a spectrum of molecules. There is not necessarily a correlation between the measured acidity and the concentration of the molecules responsible for naphthenate deposition (Lutnaes et al., 2006). Acidity of aqueous solutions is well known in terms of pH. Crude oil is not an aqueous solution; consequently, its pH cannot be measured. The method used instead is Total Acid Number (TAN), measured using a ASTM (American Society for Testing and Materials) standardized method. The standard is based on potentiometric titration with a mixture of a hydrocarbon and KOH (strong base, potassium hydroxide, completely ionized in water). The method involves dissolving an oil sample in toluene and isopropanol with a minute amount of water. A glass electrode and a reference electrode are placed in the solution and connected to a voltmeter/potentiometer. The measurement result is reported as mg KOH/g; milligrams of potassium hydroxide required to neutralize one gram of crude oil. TAN can be defined as the amount of strong base that is required to neutralise the acidity of a crude oil sample. Examples of reported TAN-values and API gravity are Sjöblom et al. (2003), Barth et al. (2004), Simon and Sjöblom (2013), Elnour et al. (2014) and Shafizadeh et al. (2003).
Automotive and Diesel Crankcase Lubricants
Published in Leslie R. Rudnick, Synthetics, Mineral Oils, and Bio-Based Lubricants, 2020
The lubricant acidity defined as TAN (total acid number) is a measure of the combined concentration of organic and inorganic acids present in used oil. The strong acid number (SAN) is a measure of the concentration of strong acids, usually inorganic acids. The difference between TAN and SAN is a measure of the concentration of organic acids. Any increase in TAN from its initial value measured in fresh oil is usually a result of oil oxidation. While it is expected for oils to undergo some oxidation processes, any exposure to severe environments such as overheating, overextended oil drain intervals, or water or air contamination can accelerate these processes.
Environmentally Acceptable Hydraulic Lubricants
Published in Brajendra K. Sharma, Girma Biresaw, Environmentally Friendly and Biobased Lubricants, 2016
Bernard C. Roell, Anne Otto, Tyler Kuchta
One key element of the oil analysis is the measurement of total acid number (TAN), sometimes simply called acid number (AN) [54]. This measures the buildup of acids in the system. The industry standard for condemning oil limit is a TAN level of 2.0 units for petroleum products [54]. As previously mentioned, acids can cause multiple problems in a system including accelerated rust and wear and seal degradation. In addition, increased acids shorten the life cycle of the fluid requiring premature oil change outs.
A comparative assessment of performance behavior of mineral-based engine oils containing metal oxide nano-particles
Published in Petroleum Science and Technology, 2022
Ajay Kumar, TCSM Gupta, Atindra Shukla
As a result of the chemical degradation, oxygenated species such as carboxylic acid and its derivatives are produced, which increases the acidity of oil (Wooton 2007; Macian et al. 2014; Wolak 2018). The enhancement in acidity of oil was measured as TAN. Additionally, the reserve alkalinity in EOs was used to counteract the TAN value and was measured as a reduction in TBN value (De Rivas et al. 2017; Wolak 2018; Golebiowski, Wolak, and Zajac 2019). The impact of chemical deterioration on the TAN and TBN values of engine oil with respect to FRH is depicted in Figure 6a, b.
Mutual compatibility aspects and rheological assessment of (modified) lignin–bitumen blends as potential binders for asphalt
Published in Road Materials and Pavement Design, 2022
Sayeda Nahar, Ted M. Slaghek, Dave van Vliet, Ingrid K. Haaksman, Richard J.A. Gosselink
Naturally occurring organic acids (i.e. naphthenic acids) present in bitumen were quantified as Total Acid Number (TAN). TAN is determined as the mass of potassium hydroxide (KOH) in milligrams that is needed to neutralise the acids in one gram of oil (mg KOH/g of oil). A standard potentiometric titration ASTM D664 – 18en ‘Standard Test Method for Acid Number of Petroleum Products by Potentiometric Titration’ (ASTM-D664, 2018) was followed to determine the TAN value of four different 70/100 bitumen.
Selection of heavy oil upgrading technologies by proper estimation of petroleum prices
Published in Petroleum Science and Technology, 2022
José A. D. Muñoz, Jorge Ancheyta, Luis C. Castañeda
This method considers the difference in prices of the actual crude oil and the benchmark crude oil according to the differences in API gravity, sulfur content and total acid number (TAN), as follows (Bacon and Tordo 2005): where pBt is the price of the benchmark crude oil at time t. Differently to the previous methods, other variables are also considered:Transportation cost and regional effect. The transportation cost between the region of the actual crude oil and that of the benchmark crude oilUtilization of refining capacity. When low-quality crude oils are used, refining capacity utilization is expected to be low and difficult, and these crude oils will be of low price. When there is no definition in the refinery that will process the crude oil, it is not possible to evaluate the effect of the crude oil properties on the available refining capacity. To overcome this situation, two new variables are introduced: (1) Index of utilization of refining capacity, which would impact on all the crude oil price differentials, and (2) Product of the index of utilization of refining capacity and API gravity differenceDynamic calculation. When some variables change over time, they could modify others such as: price of the benchmark crude oil, transportation cost and utilization of refining capacityMonthly seasonal effects. The price of crude oil and price differentials generally show the same seasonal variationTAN effect. It is only considered for crude oils with TAN higher than 0.5 mg KOH/g. Low values of TAN are supposed to generate minimum effects on refining schemes. Adding TAN in the price analysis can have a great effect on the crude oil price differential due to crude oils with high TAN limit the possibility to be refined. In recent years, an increase in TAN of crude oils has been observed, which negatively impacts the price of crude oil