Most of the equations of state (EoS) fall in a description of a corresponding state theory (CS), which is not suitable to describe the properties of real fluids. To obtain a non-conformal behavior, the EoS need to be based on at least a three-parameter model. A recently proposed equation based on a triangular well (TW) allows a non-conformal behavior to describe fluids [1].

However this EoS is based on a mean field theory, which fails to describe the region close to the critical point of the fluid. Therefore, it is necessary to include the non-classical behavior to get a correct description of this region.

In this work, the Crossover technique [2,3] is applied to the TW EoS in order to include the non-classical behavior presented in the region close to the critical point of the fluids. The obtained TW-X EoS is used to represent available molecular simulation for the TW fluid and then is extended to represent properties of different hydrocarbons. Comparisons with the original TW EoS are also presented.

[1] F.F. Betancourt-Cárdenas, L.A. Galicia-Luna, 2005 AIChE Annual Meeting, October 30-November 4, 2005, Cincinnati, OH.

[2] Z.Y. Chen, A. Abbaci, S. Tang, J.V. Sengers, Phys. Rev. A 42 (1990) 4470.

[3] S.B. Kiselev, Fluid Phase Equilib. 147 (1998) 7.