Thermodynamic Prediction of Paraffin wax precipitation in Crude oil Pipelines” Petroleum Science and Technology

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Date
2011-07
Authors
Adeyanju, Olusiji
Oyekunle, Layioye
Journal Title
Journal ISSN
Volume Title
Publisher
Taylor & Francis Production
Abstract
Crude oils are generally very complex chemical systems consisting predominantly of hundreds to thousands of hydrocarbon compounds from simple lowmolecular-weight paraffins to high-molecular-weight waxes. At low temperatures these paraffins precipitate as a wax phase, which may cause the plugging of pipes and many other problems. In this study the cloud point and the amount of the precipitated wax at different temperatures were determined using a modified multi-solid wax model at stock tank conditions and at high pressure for three live crudes and synthetic oil. The model is based on the description of the nonideality of the phases in equilibrium using the Peng-Robinson cubic equation of state for the liquid phase with a modified afunction and the universal quasi chemical (UNIQUAC) equation for the solid phase, which takes into account the effects of temperature, pressure, and composition on the wax precipitation. The model assumes the crystalline nature of wax formed. The experimental data and model predictions reveal that the cloud point decreases with increased pressure and increases when the crude oil is mixed with more light hydrocarbons. The values predicted by the new model show very little deviation from experimental data.
Description
Keywords
crude petroleum, paraffins, thermodynamic modeling, wax deposition
Citation
Oyekunle, L.O and Adeyanju, O.A. (2011).:”Thermodynamic Prediction of Paraffin wax precipitation in Crude oil Pipelines” Petroleum Science and Technology’ 29 (2), pp. 208-217. Publisher: Taylor & Francis Production.