Insights from an exergy analysis of a green chemistry chitosan biorefinery

Chitosan is a biopolymer with a wide range of applications; however, its production from chitin involves using toxic chemical solvents and high energy consumption. In this study, we propose a new greener route for producing chitosan from shrimp exoskeletons. Our design reduces chemical solvents and freshwater consumption while adhering to Green Chemistry principles. Through process simulation and exergy analysis, we identified critical stages with high irreversibility and achieved a global energy efficiency of 75%, outperforming the conventional chitosan extraction process. An exergy analysis is then conducted to identify sources of energy inefficiencies and reveal process irreversibilities. With a processing capacity of 6507 kg/h of shrimp shells, our proposed biorefinery produces valuable byproducts such as astaxanthin and minerals/proteins. The exergy analysis determined drying, dilution, and washing units as critical stages with the highest irreversibility. Our results demonstrate the potential of applying Green Chemistry principles to improve the sustainability of chitosan production from aquaculture waste streams.