Correlation of binary interaction coefficients for hydrate inhibition using the Soave-Redlich-Kwong Equation of State and the Huron-Vidal mixing rule

Abstract

This work is concerned with the calculation of binary interaction coefficients necessary for the accurate evaluation of hydrate inhibitor requirements using the Soave-Redlich-Kwong (SRK) cubic equation of state (EoS) coupled with the Huron-Vidal (HV) mixing rule. Binary interaction coefficients (BIC) of the model were determined, as a function of temperature, to predict fluid saturation pressures and composition distributions (of methanol and monoethylene glycol) at several conditions of interest. An important finding of this work is the generalization of the binary interaction coefficients as a function of the acentric factor of the hydrocarbon components. The essence of this procedure was to facilitate the evaluation of binary interaction coefficients of heavier, ill-defined fractions of a reservoir fluid. A validation of the interaction coefficients was also carried out by the comparison of the model with experimental vapour-liquid equilibrium (VLE) data. The SRK-EoS with the Huron-Vidal mixing rule and the generated BIC were found to reasonably represent the VLE of the systems tested. The results of this work could facilitate accurate estimations of inhibitor concentrations and flow rates in practical/real field operations.