Modeling high-pressure wax formation in petroleum fluids

authors	Sansot, JM; Pauly, J; Daridon, JL; Coutinho, JAP
nationality	International
journal	AICHE JOURNAL
author keywords	solid-fluid equilibrium; wax; petroleum; high-pressure; wax appearance temperature (WAT)
keywords	SEA CRUDE OILS; THERMODYNAMIC MODEL; DIESEL FUELS; PHASE-BOUNDARY; LIQUID; MIXTURES; PRECIPITATION; TEMPERATURE; HYDROCARBON; EQUILIBRIA
abstract	A procedure is presented for the simultaneous prediction of fluid-fluid and solid-fluid equilibrium of light gases/heavy hydrocarbons systems under pressure. The objective of this work is to simplify the predictive approach previously proposed by the authors, making it more useful and accessible to users at the petroleum industry. The main modification with respect to the complex LCVM (linear combination of Huron-Vial and Michelsen) mixing rule that was previously used for the attractive term "a" of the equation of state (EOS). To avoid the use of a group contribution method, which is difficult to bring into play with real fluids, the LCVM mixing rule is here replaced by the classical quadratic van der Walls one-fluid mixing rule. The deviation that using this mixing rule introduces into the gamma-phi approach is cancelled by a new parameter, introduced in the calculation of the solid-phase activity coefficient. This procedure was tested for a large range of multicomponent systems where the parameter was fitted to match the wax appearance temperature (WAT) at atmospheric pressure. From the values obtained a correlation relating the parameter to the carbon number in the heavy fraction was developed, allowing a prediction of wax formation in petroleum fluids. It is shown that this approach can successfully be applied to the prediction of wax formation at high pressure for live oils. (c) 2005 American Institute of Chemical Engineers.
publisher	WILEY-BLACKWELL
issn	0001-1541
year published	2005
volume	51
issue	7
beginning page	2089
ending page	2097
digital object identifier (doi)	10.1002/aic.10434
web of science category	Engineering, Chemical
subject category	Engineering
unique article identifier	WOS:000230059100025