Impacts of Sonochemical Process Variables on Number Average Molecular Weight Reduction of Asphaltene

Abstract

Athabasca asphaltene was ultrasonically processed under a variety of conditions. Five discrete ultrasonic frequencies and four saturating gases were explored. The kinetics of the reduction in the number average molecular weight (NAMW) were determined by vapor pressure osmometry measurements and UV/visible spectrophotometric measurements. The NAMWs decreased significantly after short treatment times (from ∼1200 to ∼470 g/mol in 15 min). The observed reduction in the NAMWs of asphaltene was greatest at 358 kHz. At a frequency of 205 kHz, the observed reduction in NAMW was fastest with a mixture of Ar/H 2 (50%/50% v/v), whereas saturating with hydrogen, air, and oxygen gases exhibited minimal effect on the kinetics. Visible light absorption spectra of asphaltene samples demonstrate that heptane soluble fractions increase by >50% after sonochemical treatment as an upgrading process.

Hydrogen-assisted fabrication of spherical gold nanoparticles through sonochemical reduction of tetrachloride gold(III) ions in water

“…Thermal conductivity of Ar, N2, O2 and H2 gas is 17.4, 26, 26.3 and 186.9 (mW m -1 K -1 ) at 25 °C and 1 atm, respectively [47], suggesting that the maximum temperature inside the collapsing bubbles increases with the order of H2 < O2 < N2 < Ar. The solubility of Ar, N2, O2 and H2 gas into water is 3.42, 1.61, 3.12 and 1.92 (x 10 -2 m 3 m -3 ) at 25 °C and 1 atm, respectively [47], which is related to the number of cavitation bubbles. Taking such atmospheric parameters into accounts, the cavitation effect and the resulting generation of reducing species (H•) should be promoted with the order of H2 < O2 < N2 < Ar.…”

“…Since the  value of Ar, N2, O2 and H2 gas is 1.664, 1.404, 1.393 and 1.384, respectively [47], the maximum temperature inside the collapsing bubbles, Tmax, should increase with the order of H2 < O2 < N2 < Ar. Thermal conductivity of Ar, N2, O2 and H2 gas is 17.4, 26, 26.3 and 186.9 (mW m -1 K -1 ) at 25 °C and 1 atm, respectively [47], suggesting that the maximum temperature inside the collapsing bubbles increases with the order of H2 < O2 < N2 < Ar. The solubility of Ar, N2, O2 and H2 gas into water is 3.42, 1.61, 3.12 and 1.92 (x 10 -2 m 3 m -3 ) at 25 °C and 1 atm, respectively [47], which is related to the number of cavitation bubbles.…”

Asphaltene Formation Damage Stimulation by Ultrasound: An Analytical Approach Using Bundle of Tubes Modeling

“…Dunn and Yen [3] successfully converted about 35% of asphaltene into gas oil and resin fractions under very mild condition using the ultrasound power and its cavitation feature. Kang et al [4] published experimental results discussing the effects of ultrasound frequency on changing the average molecular weight of asphaltene content and showed that there is no direct relationship between frequency and capability of breaking down the asphaltene molecules.…”

Influence of Ultrasonic Radiation on Asphaltene Aggregation in Model Oil Systems

“…ванию влияния ультразвукового диспергирования на физико-химические свойства нефти в лабораторных условиях [4][5][6][7][8][9][10]. Целью данных работ, в основном, было исследование влияния ультразвуковой обработки на вязкость и улучшение товарных свойств нефтей без детального экспериментального исследования надмолекулярных структур, воздействие на которые благодаря кавитационному эффекту ультразвукового диспергирования весьма эффективно.…”