Generalized Cubic Equation of State

A generalized cubic equation of state is given. The Peng-Robinson and the Soave-Redlich-Kwong equations are special cases of this equation. The generalized equation of state is precisely as simple and computationally efficient as these classical equations. Through comparison with the Span-Wagner equation for CO2, we obtain an improved density accuracy in predefined temperature-pressure domains. The results of two test cases are shown, one case in the supercritical domain and one case which contains the critical point. When compared with the Peng-Robinson equation, the root mean square density deviation is reduced by a factor 2 for the domain containing the critical point, and a factor 7 for the supercritical domain.