An efficient method for the calculation of chemical equilibrium composition in multicomponent gas mixtures

Abstract

The determination of the composition of multi-component mixtures is the basis by which a number of technical and physical problems in the field of power and process engineering are modelled. In order to calculate chemical states of equilibrium in the gas phase, a calculation method will be presented which is founded on a minimization of the Gibbs enthalpy. This method is characterized by a high reliability in convergency, considerable independence of starting vectors and by a moderate requirement for programming. These characteristics are achieved by a transformation of variables which results in numerically more favourable solutions to the non-linear equation system. Calculated equilibrium compositions (including dissociation and ionisation) for a stochiometric mixture of hydrogen and oxygen in a temperature range of 300-12000 K and a pressure of lo5 Pa as well as the application of the method will be demonstrated.

Experimental Evaluation of a Pt-based Heat Exchanger Methanol Reformer for a HTPEM Fuel Cell Stack

“…Using an efficient method of computing the reaction equilibrium by using Lagrange multipliers [10] a set of equations relating N species is set up. The Gibbs energy G will be minimal in equilibrium at constant pressure (p=p 0 =1.013 bar) and temperature:…”

“…To assist in the identification of the preferred operating conditions and the effects of changing the SC and reaction temperature, a model of the chemical equilibrium can be defined by minimizing the Gibbs free energy. Using an efficient method of computing the reaction equilibrium by using Lagrange multipliers [10] a set of equations relating N species is set up. The Gibbs energy G will be minimal in equilibrium at constant pressure (p=p 0 =1.013 bar) and temperature:…”