Prediction of solid–fluid phase diagrams of light gases–heavy paraffin systems up to 200 MPa using an equation of state–GE model

Cloud Points: Can We Measure or Model Them?

“…(Erickson et al, 1993;Coutinho et al, 2001) or may be described using a free energy model (Won, 1986;Hansen et al, 1988;Coutinho et al, 1996;Lira-Galena et al, 1996). For high pressure systems (live oils), on the other hand, the liquid phase is generally described using an Equation of State (Lira-Galena et al, 1996;Pan et al, 1997;Pauly et al, 2000).…”

Modeling high‐pressure wax formation in petroleum fluids

“…With respect to the previously proposed model, 1 the mixing rules were simplified and the classical mixing rules (quadratic for a and linear for b) were used with interaction parameter k ij , evaluated by the correlations proposed by Pan et al 17 The critical properties required in the evaluation of the EOS parameters were obtained from the compilation of Reid et al 26 for light gases, whereas the Twu correlation 27 is used to predict the critical properties of the heavy components. Because the slope of the melting line with pressure is closely related to the volume change of solid-fluid-phase transition, the volume of each phase has to be properly evaluated by the model for a good prediction of the pressure influence on liquid-solid-phase equilibrium.…”

“…Because the slope of the melting line with pressure is closely related to the volume change of solid-fluid-phase transition, the volume of each phase has to be properly evaluated by the model for a good prediction of the pressure influence on liquid-solid-phase equilibrium. To achieve this requirement, the volumetric properties calculated by the original PR EOS are corrected by using a volume translation introduced by Peneloux et al 28 V ϭ VЈ ϩ C i (1) where VЈ represents the volume calculated from the PR EOS and C i is a translation parameter estimated at atmospheric pressure. 29…”

“…The situation has become increasingly worse, with the ongoing trend to deep water developments, and a predictive model that could help flow assurance teams on the design and preventive maintenance of pipelines would be a most valuable tool. 1 Most of the experimental and simulation investigations carried out on the precipitation of heavy paraffins were undertaken at atmospheric pressure for dead oils, fuels, [2][3][4][5][6][7][8][9][10] and synthetic systems. [11][12][13][14][15][16] Nevertheless, investigation of paraffin precipitation cannot be dissociated from the pressure effect because the gases in the live oil can have a considerable influence on the wax appearance temperature (WAT) by decreasing it as much as 15 K between atmospheric and saturation conditions, 17,18 and produce an increase of the WAT of about 2 K for each 10 MPa above that point.…”

Fundamental Study of Wax Deposition Under Real Flow Conditions

“…In this sense, the study about the influence of light components, as CO2 and CH4, becomes very important, since they may change the conditions under which the paraffins precipitate. Thus, the use of reliable experimental phase equilibrium data, which should cover a broad range of pressure, temperature and composition, is fundamental for the development and validation of thermodynamic models for these systems (Pan et al, 1997;Pauly et al, 2000;Pauly et al, 2012).…”