An Electrical Computer for Solving Phase Equilibrium Problems

Abstract

Introduction In both production and refining operations of the oil industry manyprocesses are controlled by the gas-liquid phase relationships of thehydrocarbon mixtures of interest. The quantitative behavior of fractionating ordistillation columns and stills depends on the changes in the equilibriumdistributions of the hydrocarbon components between the gas and liquid phasesas the pressure or temperature conditions may vary along the length of thecolumn or as the gross operating parameters and compositions are varied. In oilproducing operations the nature and amount of gas phase developed within anunderground reservoir as it is being depleted and its pressure declines alsoinvolve the basic equilibrium gas-liquid phase interactions. The influence ofsurface conditions of temperature and pressure and various separationprocedures on the nature and amount of stock tank oil and natural gas recoveredfrom a given well stream is likewise determined by the same basic phaseequilibrium characteristics of the hydrocarbon systems. Such equilibriumseparation of the gas and liquid phases in a well stream is of importance bothin establishing optimum separator conditions for obtaining maximum stock tankoil yields and in the general problem of crude stabilization. The phenomena involved in these problems and their quantitative aspects can, of course, be established in each individual instance by appropriate laboratoryexperimentation. It has been found, however, that by associating with theindividual hydrocarbon components functional characteristics describing theirindividual gas-liquid phase equilibrium behavior, the phase properties of thecomposite mixtures can be predicted by mathematical computation. T.P. 2733