Computer-aided exergy analysis of agar production process from macroalgae Gracilaria sp.

Abstract

In this work, an agar production process from macroalgae Gracilaria sp. is analyzed using exergy analysis methodology in order to quantify the physical and chemical exergies of the species involved, total irreversibilities, exergy from utilities and wastes generated, and overall exergy efficiency of the process. Results show that for an 8,670 t/year of Gracilaria sp. algae plant, the Filtration III and Evaporation stages have a great improvement opportunity since the use of waste streams such as water vapor, water and filter cake increase the exergy efficiency from 18.7 to 39.4%. Finally, it is suggested an improved topology to optimize the process by the implementation of an energy integration to reduce exergy of industrial services as well as operating costs.