Scaling down of flash calculations of natural gas with the aid of pseudocomponents

Abstract

The prediction of vapor-liquid equilibrium of natural gas deals with the calculation equilibrium K values based on the Soave-Redlich-Kwong equation of state and the phase compositions by flash calculations. Service of a computer is required due to the iterative nature of the calculation. Because of many equations to be solved simultaneously, much computing time is required. Therefore, in this work, the pseudocomponents model was introduced to scale down the computing time. With this model, the computing time was saved to 32% of the ordinary method. The percentage average deviation was the range of 0.6 to 3.1. This proposed model was tested at low and moderate pressure ranging from 150.0 psia to 1115.0 psia abd a temperature range if -8.0 F.