Simultaneous design of macroalgae-based integrated biorefineries and their heat exchanger network

Abstract

In this work we propose a model for the optimal design of macroalgae-based integrated biorefineries for the production of chemicals and biofuels, through superstructure generation including the simultaneous heat exchanger network (HEN). We formulate MINLP problems with sustainability (RePSIM) and economic (NPV) objective functions, respectively. As novelty, simultaneous design of the process and its HEN is carried out in a large-scale problem, with more than 50,000 continuous and 10,000 binary variables. Experimental data was obtained in our laboratory for brown algae conversion into sorbitol. Heat integration provides a reduction of 70.7% in utility costs with respect to the non-integrated case in NPV maximization. When RePSIM is the objective function, heat integration provides 2.3% increase, with 79.0% utility savings. Simultaneous Process and HEN design has proven to be efficient and robust, as well as a valid approach for energy savings in the optimal design of large-scale sustainable processes.