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

Abstract

Asphaltenes can cause serious problems to petroleum industry. Indication of asphaltenes stability can be obtained by precipitation induced by n-heptane, monitored by near-infrared (NIR). However, this technique does not provide information on the particles sizes. In this study, the precipitation onset of model systems (1wt% asphaltenes in toluene) was monitored by NIR, with and without adding additive. The particles sizes of the same systems were monitored by atomic force microscopy (AFM): Dispersions of asphaltenes in toluene, n-heptane and mixtures of these two solvents were analyzed by AFM. For the pure model system, the size of the asphaltenes aggregates clearly increased in function of rising n-heptane concentration in the solvent mixture, with this increase being much more pronounced for solubility parameter values below that corresponding to the precipitation onset. In the presence of additives, significantly smaller particles were obtained even when the precipitation onset showed only a slight shift.

Flocculation of Asphaltenes by Polymers: Influence of Polymer Solubility Conditions

“…In some cases, the deposition of asphaltenes can be prevented by changing the processing conditions, such as the temperature and pressure, so that the crude oil will not be subjected to conditions that favor aggregation. However, usually these conditions cannot be varied easily, mainly during production, so it is necessary to add asphaltene aggregation inhibitors and dispersants. − …”

Influence of Asphaltene Aggregation State on the Wax Crystallization Process and the Efficiency of EVA as a Wax Crystal Modifier: A Study Using Model Systems

“…In general, studies of asphaltenes are related to the factors that provoke the phase change (precipitation) or the interfacial and colloidal effects on the stabilization of fine particles in suspension (flocculation). Such events are normally associated with variations in the temperature, pressure, and composition of the crude oil. ,− There are different studies proposing the growth system of the asphaltene structures. Some authors propose the following growth: monomers → micelles → particles → precipitated. , Others proposed a growth system of molecule → nanoaggregate → clusters …”

Evaluación de aceite de Jatropha gossypiifolia como estabilizante de asfaltenos en una muestra de petróleo a nivel de laboratorio

“…Los asfaltenos por ser los componentes más pesados del petróleo y por encontrarse en un estado de pseudoestabilidad, bajo ciertas condiciones desfavorables de presión, temperatura, composición química y tasa de corte, se precipitan afectando de manera negativa la recuperación de petróleo (Sulaimon, De Castro & Vatsa, 2019;Sepúlveda, Bonilla & Medina, 2010;Figueira, Simão, Soares & Lucas, 2017). La teoría más aceptada para definir el comportamiento de los asfaltenos en el petróleo es la teoría coloidal, en la cual los asfaltenos existen en el petróleo como partículas sólidas en suspensión coloidal estabilizada por resinas adsorbidas sobre su superficie (Akbarzadeh et al, 2007;Mansoori, 2009;Chavez, Campo, Morales & Carrillo, 2011).…”