THERMODYNAMICS FOR SOLID SOLUTION-LIQUID-VAPOR EQUILIBRIA - WAX PHASE FORMATION FROM HEAVY HYDROCARBON MIXTURES

This paper presents a thermodynamic prediction method of vapor-liquid-solid wax phase equilibria of paraffinic hydrocarbon mixtures. Wax build up phenomena inside oil and gas transmission pipelines have long been recognized and various techniques are in practice to prevent its formation. However, no thermodynamic calculation method has been published in open literatures. A previous paper by author presented liquid-solid equilibria of hydrocarbon mixtures using ideal solution assumption. This paper uses a new 'modified regular solution' theory for the liquid-solid equilibria and Soave Redlich-Kwong equation of state for vapor-liquid equilibria and presents the three-phase equilibrium calculation method.