Inhibition of Asphaltene Precipitation by TiO₂, SiO₂, and ZrO₂ Nanofluids

Abstract

Asphaltene precipitation causes several problems during crude oil production, transportation, and refinery processes. Therefore, finding an inhibitor to prevent or delay asphaltene precipitation is of paramount importance. In this work, effects of TiO2, ZrO2, and SiO2 fine nanoparticles in organic-based nanofluids have been investigated to study their potential for stabilizing asphaltene particles in oil. To this end, polarized light microscopy has been applied to determine the onset of asphaltene precipitation by titration of dead oil samples from Iranian crude oil reservoirs with n-heptane in the presence of nanofluids. Results show that rutile (TiO2) fine nanoparticles can effectively enhance the asphaltene stability in acidic conditions and act inversely in basic conditions. It was found that the required amount of n-heptane for destabilizing the colloidal asphaltene is considerably higher in presence of TiO2 nanofluids at pH below 4. The FTIR spectroscopy indicates changes in n-heptane insoluble asphaltene when acidic TiO2 nanofluid is used as inhibitor. According to the results obtained by FTIR spectroscopy, TiO2 nanoparticles can enhance the stability of asphaltene nanoaggregates through formation of hydrogen bond at acidic conditions. This is while other materials used in this experiment, as well as the TiO2 nanoparticles in basic conditions, are unable to form any hydrogen bond – hence their incapability to prevent asphaltene precipitation. Dynamic light scattering (DLS) measurements also have been performed to explain the mechanism of asphaltene precipitation in the presence of nanoparticles.

On the application of NiO nanoparticles to mitigate in situ asphaltene deposition in carbonate porous matrix

“…Determination of asphaltene content in the output oil samples shows the asphaltene amount to have nominal change and to remain nearly equivalent to its initial value in the process. This indicates that the asphaltene had not undergone any precipitation in the core, which is partially in contrast to some literature results (Mohammadi et al 2011). It also indicates the ineffectiveness of the considered parameters on asphaltene precipitation, in this case.…”

“…These included experiments with oil samples containing dissolved gas in the solution (live oil sample) and oil samples without dissolved gas (dead oil sample). Mohammadi et al (2011), for instance, conducted experiments with dead oil samples under static conditions to study the effects of TiO 2 , SiO 2 and ZrO 2 nanoparticles, and concluded that TiO 2 nanoparticles can enhance the stability of asphaltene nanoaggregates through formation of hydrogen bonds at acidic conditions (pH \ 4) and having an inverse effect at basic conditions. Nasser et al (Nassar et al 2012a, b;Nassar et al 2011) experimentally confirmed the ability of NiO, CO 3 O 4 and Fe 3 O 4 nanoparticles to improve the thermal decomposition of asphaltenes.…”

Adsorption-desorption of n–C7 asphaltenes over micro- and nanoparticles of silica and its impact on wettability alteration

“…Then, n-heptane is added to the solutions to attain the desired concentration of n-C 7 asphaltenes in the chosen Heptol proportions, and the solution is stirred again for 72 h to ensure n-C 7 asphaltene stability (Maqbool, Balgoa, & Fogler, 2009;Nassar et al, 2015a). Before the adsorption experiments, it was corroborated that the n-C 7 asphaltenes do not precipitate from the prepared model solutions using the Oliensis spot test number (Asomaning, 2003;Oliensis, 1935) and polarized light microscopy (Franco et al, 2015;Mohammadi, Akbarit, Fakhroueian, Bahramian, & Sharareh, A. 2011).…”

Investigation of Asphaltene Adsorption onto Zeolite Beta Nanoparticles to Reduce Asphaltene Deposition in a Silica Sand Pack

“…The base fluid should be a clear liquid for better observation of nanoparticle stability. Nanoparticles dispersion procedure was conducted using a probe ultrasonic (400 W and 24 kHz) to break agglomerates of nanoparticles in the fluid and make stable suspension [28,29]. It was observed with naked eyes that the nanofluid was uniformly dispersed for 24 h and the complete sedimentation happened after three days.…”