Effect of Hydrothermal Carbonization on Fuel and Combustion Properties of Shrimp Shell Waste

Abstract

Shrimp shell is a popularly consumed seafood around the globe which generates a substantial quantity of solid wet waste. Hydrothermal carbonization (HTC) could be a viable pathway to convert wet shrimp shell waste into energy-dense hydrochar. The present study aims to assess the fuel properties, physicochemical attributes, and combustion properties of shrimp shell hydrochar generated with a wide range of HTC temperatures (110–290 °C). Results showed that a rise in carbonization rate results in a decline in mass yield to as low as 25.7% with the increase in HTC temperature. Thermogravimetric analysis indicates shrimp shell hydrochars to be more thermally stable than raw dried feedstock. Results from the bomb calorimeter report a maximum HHV of 27.9 MJ/kg for SS-290, showing a 13% increase in energy densification compared to raw shrimp shell. The slagging and fouling indices determined for the hydrochars further assisted in addressing the concern regarding increasing ash content changing from 17.0% to 36.6%. Lower ratings of the slagging index, fouling index, alkali index, and chlorine content for hydrochars at higher temperature indicate the reduced probability of reactor fouling during combustion. The findings of the analysis demonstrate that HTC is a promising approach for transforming shrimp shell waste into a potential fuel replacement.