In the present paper, a bi-level optimization approach is proposed to synthesize Heat Exchanger Networks (HEN), based on a hybrid meta-heuristic method. Simulated Annealing (SA) is used to optimize the HEN topologies and Differential Evolution (DE) is applied to the continuous variables. The model is derived from a superstructure and considers streams split and non-isothermal mixing. The code was implemented in C++, which leads to an improvement in the execution times in comparison to previous literature studies. Four case studies were used to test the applicability of the developed model and results showed that it is possible to achieve optimal values, better than those presented in the literature. (C) 2019 Elsevier Ltd. All rights reserved.