An algorithm for calculating critical points in multicomponent mixtures which can easily be implemented in existing programs to calculate phase equilibria

摘要: Abstract This paper describes an add-on procedure for the calculation of critical points in multicomponent mixtures according to method by Heidemann and Khalil [1] . The benefit this approach is that all equations state (EOS) mixing rules existing program calculating phase equilibria, which can be a commercial product or self-made, are available points. requires first second partial derivatives fugacities with respect male numbers ( ∂ ln f k / n i ) T,V,n i≠j 2 l j l≠i,j In our work obtained numerically four-point differencing scheme from numerical directional derivative as suggested Michelsen [2] new allows combination any equilibria eliminates need cumbersome determination analytical fugacity mole numbers. implementation into commercially process simulator ASPEN PLUS Version 9.2 [3] described some results shown.