An experimental study of asphaltene particle sizes in n-heptane-toluene mixtures by light scattering

Abstract

-The particle size of asphaltene flocculates has been the subject of many recent studies because of its importance in the control of deposition in petroleum production and processing. We measured the size of asphaltene flocculates in toluene and toluene -n-heptane mixtures, using the light-scattering technique. The asphaltenes had been extracted from Brazilian oil from the Campos Basin, according to British Standards Method IP-143/82. The asphaltene concentration in solution ranged between 10 -6 g/ml and 10 -7 g/ml. Sizes was measured for a period of about 10000 minutes at a constant temperature of 20°C. We found that the average size of the particles remained constant with time and increase with an increase in amount of nheptane. The correlation obtained for size with concentration will be useful in asphaltene precipitation models.

A comprehensive study on mechanism of formation and techniques to diagnose asphaltene structure; molecular and aggregates: a review

“…Light scattering and laser particle analyzer techniques are two other methods to study asphaltene aggregation in different experimental conditions. The results of light scattering studies represent that depending on the asphaltene concentration, the size of aggregates changes in the range of nanometers . The effect of pressure and temperature on asphaltene aggregate size was studied using the laser particle analyzer technique.…”

A combined QCM and XPS investigation of asphaltene adsorption on metal surfaces

“…The difference in estimated thickness from the present study and that in literature may be due to the nature of the adsorbent, the concentration range, the measurement techniques employed and the nature of asphaltene itself. The asphaltene particle diameter in toluene studied by freeze fracture-transmission electron microscopy (FFTEM) were in the range of 7-9 nm [30], studied by small angle neutron scattering (SANS) were in the range of 6-20 nm [29], while light scattering techniques have suggested the average asphaltene particle size to be 23 nm [35].…”

The influence of chemicals on asphaltenes precipitation: a comparison between atomic force microscopy and near infrared techniques

“…The size of asphaltenes aggregates can be monitored by measuring the light scattered (Rajagopal & Silva, 2004) (Mansur, Melo & Lucas, 2012). However, this technique can only be applied to model systems with very low asphaltenes concentrations, which often does not allow studying model systems that reproduce the characteristics of the crude oil of interest.…”