Eventos Anais de eventos
ENCIT 2016
16th Brazilian Congress of Thermal Sciences and Engineering
THE INFLUENCE OF THE SUPERCOOLING ON THE MECHANICAL PROPERTIES AND CRYSTAL MORPHOLOGY OF WAXY OILS
Submission Author:
Diogo Elias da Vinha Andrade , RS
Co-Authors:
Talita Janaina Heller, Moisés Marcelino Neto, Cezar Otaviano Ribeiro Negrao
Presenter: Diogo Elias da Vinha Andrade
doi://10.26678/ABCM.ENCIT2016.CIT2016-0149
Abstract
Waxy crude oil is a complex mixture of hydrocarbons consisting of paraffins, aromatics, naphthenes, asphaltenes and resins. At low temperatures the solubility of high molecular weight components in the oil is decreased and mainly the n-paraffins tend to precipitate as crystal structures. These crystals not only provide a non-Newtonian behavior to the fluid but also tend to deposit in the inner surface of pipelines and are responsible for the gelation of the oil when the flow is interrupted. Crystallization is the process where an ordered solid structure is formed from a disordered phase. This process involves two main stages, namely nucleation and crystals growth. As paraffins nucleation is a stochastic process, a supercooling is needed to the onset of this phenomenon. In other words, it could be not possible to occur the precipitation of crystals exactly in the solid-liquid equilibrium thermodynamic temperature, namely in petroleum area as Wax Appearance Temperature – WAT. Therefore, during the cooling it is required that the fluid reaches a certain temperature, below the WAT, to initiate the nucleation process. The difference between the WAT and the crystallization temperature is named as degree of supercooling. In this work the influence of the cooling rate on the supercooling is investigated. The supercooling is related to mechanical properties of waxy crude oils and to the morphology of wax crystals. The analysis is conducted by means of rheometric tests. It can be anticipated that it is possible to associate the degree of supercooling with the mechanical properties and with the crystal morphology of waxy oils.
Keywords
waxy oil, wax crystallization, supercooling, crystal morphology, Mechanical Properties, waxy oil, wax crystallization, supercooling, crystal morphology, Mechanical Properties, waxy oil, wax crystallization, supercooling, crystal morpholgy, Mechanical Properties, waxy oil, wax crystallization, supercooling, crystal morphology, Mechanical Properties, crystal morpholgy
