A simple model for temperature-independent k_ij of the PR-vdW model for mixtures containing HCs, HFCs, PFCs, HFOs, CO₂, RE170 and R13I1

The purpose of this paper is to establish a simple model for temperature-independent binary interaction parameter k_ij of the PR-vdW model (Peng-Robinson equation of state with van der Waals one-parameter mixing rules). The model was proposed as k_ij = w_jk_i + w_ik_j (i ≠ j). In the present model, every pure component was considered to have a constant contribution k_i to k_ij, constant w_i is the contribution coefficient of component j mixing with component i. k_ij can be determined by summing the contribution coefficient of each pure component times its contribution. By regressing the vapor-liquid equilibrium (VLE) data of binary mixtures, 119 k_ij were obtained and used to optimize the constant contribution k_i and contribution coefficient w_i. k_ij of 351 binary systems were predicted and used to describe the VLE data of binary and ternary mixtures. Better performs could be found in the present model than the available models on VLE description of the mixtures.