Design of heat integrated distillation systems for a light ends separation plant

This paper presents an industrial case-study: the synthesis of partially thermally coupled and heat-integrated distillation systems applied to the light ends separation section of a crude distillation plant. The distillation systems presented in this work employ the thermal coupling and the heat-integration principles to significantly reduce the heat requirements with respect to the traditional simple column train. The work started from the simulation of the existing plant, by which the parameters of the system were identified. Then the possible sequences of simple columns with sharp splits were identified for the considered application, and all the columns of the configurations were designed. The corresponding thermally coupled sequences were obtained by using a simple procedure derived from the literature and the heat-integrated partially coupled configuration (HIPC) was also considered. In order to verify the examined distillation systems, all the simple and complex configurations were simulated by rigorous numerical models. On the basis of the numerical simulations, the energy requirements for each configuration were evaluated. A rating of the different plants was then performed, based on the total annual cost, allowing to identify the best plant configuration. A thermally coupled configuration showed the best performances for the considered separation.