Electrophoretic Mobility and Stabilization of Asphaltenes in Low Conductivity Media

Abstract

The electrophoretic mobilities of asphaltenes in n-heptane and ethanol were determined. The asphaltenes studied show a positive charge in both solvents. However, the magnitude of the charge is considerably lower in n-heptane than in ethanol. It is concluded that although the electrostatic forces are presented in both solvents, the van der Waals' atractive forces are the main responsable for the flocculation of asphaltene particles. The addition of a well known asphaltene stabilizer, dodecyl benzene sulphonic acid (DBSA), decreases the electrophoretic mobility of asphaltene particles in ethanol until a constant positive value is reached. This means that the neutralization of the positive charges of the asphaltene particles is not complete, probably due to the limited adsorption of the DBSA on asphaltene surface and also, to the presence of charges inside the asphaltene particles that are not accessible to the DBSA.

Development of oxazolidines derived from polyisobutylene succinimides as multifunctional stabilizers of asphaltenes in oil industry

“…Two chemicals were selected for benchmarking and comparison purposes: Dodecylbenzene sulfonic acid (DBSA), which has been extensively reported in specialized literature as synthetic Asph dispersant [12,[16][17][18][19][20], and a commercially available Asph stabilizer (CPA) based on polyisobutylene.…”

Effect of particle and surfactant acid–base properties on charging of colloids in apolar media

“…In the 1950s, van der Minne and Hermanie from the Shell research laboratories found that dispersions of carbon black in benzene were stable only when a considerable zeta potential was detected, and hence demonstrated the contribution of electrostatic repulsion to the stability of apolar colloidal dispersions [1,2]. Today, electrostatic repulsion is said to play a role in colloidal stabilization in many applications of apolar systems, including prevention of solid sedimentation in petroleum processing [3], dispersion of particles in supercritical CO 2 [4], and stabilization of particles for airborne drug delivery [5]. However, in other areas, electrostatic stability of the particles alone is not sufficient, and the ability to manipulate the particle's polarity, surface charge density, and response to external electric fields is required.…”

Dynamic asphaltene deposition control in pipe flow through the application of DC potential

“…Whereas some researchers claimed that asphaltene possess a predominantly positive charge in most non-aqueous dispersants (James and Richard 1963;Lichaa and Herrera 1975;Leon et al 2000;Gonzalez et al 2003), some reported their net negative surface charges based on electro-deposition experiments with neat crude oil samples (Idem and Ibrahim 2002;Nasser and Belhaj 2010;Belhaj and Khalifeh 2013). Also noteworthy is the work of Leontaritis and Mansoori (1987) who showed that the net negative charge on asphaltene colloidal surface is the prime cause of deposition on metal pipes due to the potential difference across them.…”

“…This resulted with the hypothesis that, any effort in neutralising this charge may result in controlling asphaltene precipitation and deposition (Yen 1994). Leon et al (2000) from their electrophoretic mobility studies with 27 crude oils established that the surface charges on asphaltene micelles were predominantly negative in crude oils and at low heptanes dilution but the surface charges were reversed at higher dilution. The charge reversal was attributed to removal of positively charged peptizing resins.…”

“…Electrokinetic, electrophoretic and adsorption properties of asphaltenes are studied through potentiometric and electrokinetic measurements in great details on various crude oils which firmly established its charge-bearing properties and streaming potential (Kokal et al 1995;Leon et al 2000;Gonzalez et al 2003;Parra-Barraza et al 2003). Asphaltenes in aqueous solutions are found to possess surface charge as a result of protonation and dissociation reactions of functional groups enabling electrophoretic mobility (Janusz and Jablonski 2000).…”