Eventos Anais de eventos
COBEM 2021
26th International Congress of Mechanical Engineering
THERMODYNAMIC-BASED, ONE-DIMENSIONAL PIPELINE WAX DEPOSITION MODEL
Submission Author:
Fabio Gaspar Santos Júnior , SP , Brazil
Co-Authors:
Fabio Gaspar Santos Júnior, Felipe Fleming, Luis Fernando Alzuguir Azevedo, ivan fernney ibanez aguilar, Angela Nieckele
Presenter: Fabio Gaspar Santos Júnior
doi://10.26678/ABCM.COBEM2021.COB2021-2258
Abstract
Wax deposition in oil and gas subsea pipelines is one of the main problems associated with flow assurance. As the oil flows from the reservoir to the platform, it loses heat to the cold ocean environment. Solid crystals appear when the mixture temperature is below the Wax Appearance Temperature. The solids can form deposits at the wall, increasing the required pumping power, or even completely obstructing the flow, resulting in significant maintenance and capital losses. Since pipelines are normally very long, one-dimensional models are required to predict wax deposition along the pipe walls. Wax deposition 1D codes available in the literature are based on molecular diffusion as the main deposition mechanism and require several adjustable empirical constants to fit to field data. In the present work, a novel methodology based on a thermodynamic model for the liquid-solid mixture coupled with 1D hydrodynamic calculation and a 2D heat transfer calculation is employed to predict wax deposit formation. From the flow, pressure and temperature distribution and initial species composition, the solid fraction and all the fluid properties are determined with the aid of the thermodynamic model. It is assumed that the wax deposits are formed when the solid fraction is above 2%. Validation with experimental data obtained from a laboratory-scale annular test section was performed, and reasonable agreement was obtained.
Keywords
Wax deposition, One-dimensional model, Flow assurance, thermodynamic model
