This paper explores the thermogravitational separation of binary fluid mixtures in porous media, focusing on the interplay between convection and thermodiffusion. The study aims to optimize this separation using an innovative experimental configuration: a horizontal cavity subjected to a constant vertical heat flux.The first chapter presents the theoretical foundations of thermogravitational diffusion, discussing the contributions of pioneers such as Ludwig and Soret, as well as the importance of porous media. The second chapter examines thermogravitation in a vertical cell, revealing that significant separations can be achieved, although the optimal cell thickness is very small, complicating its practical application.The third chapter introduces the horizontal configuration, demonstrating that it achieves similar levels of separation, but with larger cell dimensions, thus facilitating experimentation. The results underline the importance of coupling convection and thermodiffusion to maximize separation efficiency.