Polycardanol and Poly(cardanol‐co‐styrene): Synthesis, Characterization, and Performance as Asphaltene Flocculant

Abstract

The destabilization of asphaltenes in crude oil mainly happens due to variations in pressure, temperature, and oil composition; causing significant losses. Polymers containing specific groups can be used as asphaltene stabilizers, thus avoiding their precipitation, or as asphaltene flocculants in a particular type of unconventional oil, for example, assisting in further destabilization of the model system to enable removal of suspended fine solids, such as kaolinite. Asphaltene precipitation is usually evaluated by tests with variation in stability of asphaltenes in function of adding a flocculant solvent. In this work, two molecules with different amounts of cardanol and styrene are synthesized and structurally characterized by FTIR and 1H NMR. Their molar mass is also determined by SEC and their thermal stability is measured by TGA. In addition, the efficiency of these synthesized molecules as asphaltene dispersants or flocculants is analyzed. The stability of asphaltenes is monitored by precipitation tests induced by a flocculant agent (n‐heptane), using an ultraviolet–visible (UV–vis) spectrometer. The synthesis results indicated formation of an oligomer instead of a polymer. The asphaltene stability results indicate that the synthesized molecules can act as asphaltene flocculants, decreasing the onset of precipitation to smaller volumes of n‐heptane. Furthermore, the increase in concentration of these synthesized molecules in the model systems containing asphaltenes dispersed in mixtures of toluene and n‐heptane in different concentrations promote greater flocculant action of the asphaltenes.

Cardanol/SiO2 Nanocomposites for Inhibition of Formation Damage by Asphaltene Precipitation/Deposition in Light Crude Oil Reservoirs. Part I: Novel Nanocomposite Design Based on SiO2–Cardanol Interactions

“…The characterization of the cardanol was based on the methodology of our previous research studies. ,,− Consequently, according to the GPC analysis, the CDN sample shows that the number-average molecular weight of cardanol molecules is 301 g·mol –1 , which is near to the estimated average molecular weight of several research groups. , Figure S1 shows the 1 H NMR spectrum of the cardanol sample, and Table S1 summarizes the types of hydrogen found in the cardanol structure and their respective atomic percentual fractions. The NMR analysis indicates that the most predominant hydrogen proton is the aliphatic one, reaching an atomic percentual fraction of 41.2, associated with the C 15 alkyl chain located in the meta position of the phenolic ring.…”

“…The CDN sample was characterized by Fourier transformed infrared spectroscopy (FTIR) using an IRAffinity-1 infrared spectrophotometer (Shimadzu, Japan) by the cast film technique in a KBr cell from 650 to 6500 cm –1 with a resolution of 4 cm –1 . , Besides, the average molecular weight and the type of aromatic and aliphatic hydrogen atoms of the CDN sample were obtained by gel permeation chromatography (GPC) and hydrogen nuclear magnetic resonance ( 1 H NMR) using the protocols employed in the previous works. , …”

“…In this sense, asphaltene stability is a function of the ratio of asphaltenes to stabilizing compounds in crude oil, such as aromatics and resins . Molecular interactions, such as π–π interactions, hydrogen bonds, and acid–base interactions, are responsible for the self-association of the molecular structure promoting the tendency of the asphaltenes to aggregate. , This produces the aggregate size growth until flocculation occurs since solubilization in the liquid becomes too weak to keep the asphaltenes in the solution. ,, …”

Reduction of asphaltenes adsorbed on kaolinite by polymers based on cardanol

“…The asphaltene adsorption on the surface of clay minerals plays an important role in the oil industry: (i) altering the wettability, in which particles in contact with the crude oil change their hydrophobicity character; (ii) causing the fouling of the catalysts; and (iii) contaminating the bitumen, reducing the quality of the oil and hence generating higher costs (Dudášová et al 2008;Lucas et al 2009Lucas et al , 2015Nikakahtari et al 2013;Wang et al 2013;Osaky et al 2014;Maravilha and Spinelli, 2018;Neuhaus et al 2019). Although many researches have been done on tailing ponds treatment, this process still need to be improved (Nikakahtari et al 2013;Reis et al 2016;Vajihinejad et al 2017;Gumfekar and Soares 2018a, b;Vajihinejad and Soares 2018;Younes et al 2018).…”

“…Polymers have been extensively used as additives in the petroleum industry (Lucas et al 2009(Lucas et al , 2015Brostow and Lobland 2016). Specifically for tailing ponds, polymer flocculants may accelerate tailings dewatering (Bazoubandi and Soares 2020).…”