Evaluation of shrimp waste valorization combining computer-aided simulation and numerical descriptive inherent safety technique (NuDIST)

Nowadays, inherently safer designs are considered as key priorities to prevent or mitigate serious incidents with devastating consequences. The need for process safety assessment during early design phases has motivated the development of several contributions related to computer-aided assessment methodologies to measure the inherent safety of chemical processes. In this work, the large-scale production of chitosan from shrimp wastes was evaluated from a process safety point of view using the numerical descriptive inherent safety technique (NuDIST). To this end, simulation of the chitosan production was performed using Aspen Plus® to obtain extended mass and energy balances. The assessment of all the chemicals involved within the process was carried out for the following safety parameters: explosivity (EXP), flammability (FL), and toxicity (TOX). The safety assessment of the process included the parameters of temperature (T), pressure (P), and heat of reaction (HR). The maximum chemical safety score was estimated in 171.01 with ethanol as the main contributor to the parameters of explosivity and flammability. The score associated with operating data was calculated at 209.20 and heat of reaction reported to be the most affecting parameter. The NuDIST score was estimated at 380.20. This NuDIST value revealed the low hazards associated with the handling of substances such as shrimp wastes, chitosan, and water, as well as the non-extreme temperature and pressure conditions. In general, the large-scale production of chitosan from shrimp shells was shown to be an inherently safe alternative of waste valorization.