The formation of solid phase in hydrocarbon mixtures in a cold environment in one of the major problems faced by the petroleum

MODELLING OF WAX PRECIPITATION AT LOW AND HIGH PRESSURE: PRESENTATION OF A FREE CONVIVIAL SOFTWARE

Jérôme Pauly^a, J.A.P. Coutinho^b, Jean-Luc Daridon^a.

^a Laboratoire des Fluides Complexes - Groupe Haute Pression, Université de Pau, BP 1155, 64013 PAU Cedex (France). Fax : (33) 5 59 40 76 91; Email : jerome.pauly@univ-pau.fr

^b CICECO. Departamento de Quimica da Universidade de Aveiro, 3810-193 Aveiro, Portugal

The formation of solid phase in hydrocarbon mixtures in a cold environment in one of the major problems faced by the petroleum industry. The phase behaviour of this complex hydrocarbon mixtures forms one of the important specifications. Thus a thermodynamic model able to predict the wax formation in the oil from the knowledge of its properties would be a very valuable help for the design of transport facilities and the operation of reservoirs of potentially problematic oils. A number of wax models are currently in use by the oil industry which are based on parameters that were empirically determined to match available data for black oils. Our team and Co-workers have investigated the thermodynamics of oil-wax equilibrium over a number of years. This presentation aims to make an rapid overview of all the different versions of our thermodynamic models for multiphase equilibrium at low and high pressure. From the basis model of Coutinho et al. for the representation of liquid –solid equilibrium at atmospheric pressure, we have developed a predictive model for high pressure fluid-solid equilibrium (Pauly et al.). These models, already presented in previous conferences, give very accurate results for the prediction of the WAT in both synthetic mixtures and real systems.

Then a free convivial interface has then been developped in order to make this program usable for academic and industrial people. The version presented here is a very simple interface which allows for the user to make a multiflash calculation. The only input parameters are the detailed composition of the fluids as well as the pressure and the temperature.