Energy utilization potential of crustacean biomass: comprehensive evaluation of co-combustion with coal

Resource utilization of bio-waste and synergistic control of gaseous pollutants is the way to achieve low-carbon and high-quality development. Crustacean biomass is usually characterized by well-developed pores and abundant functional groups, making it a potential and efficient biofuel. In this study, Fourier transform infrared (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), and specific surface area analyzer (BET) were used to characterize the physicochemical properties and pore structure of shrimp and crab shells. The results show that crab shells are rich in microporous and mesoporous structures, and shrimp shells have large and regular pores. The developed pores endowed both with good combustion potential. And thermogravimetric-mass spectrometric (TG-MS) experiments were conducted to investigate the combustion performance and gaseous pollutant emission characteristics of crab shells and shrimp shells blended with bituminous coal. It was found that the addition of shrimp and crab shells could significantly reduce the ignition temperature and improve the combustion performance. Meanwhile, the rich calcium carbonate in crab and shrimp shells was effective in fixing SO2. Compared with pure bituminous coal combustion, SO2 emissions were reduced by 63.15% and 52.31%, respectively. The kinetic parameters of the blends were evaluated by Coats&Redfern method using n-level reaction modeling. The activation energy values decreased from 84.169 to 37.660 kJ/mol and 69.429 kJ/mol with the addition of shrimp and crab shells, respectively. This study provides a new perspective on the energy utilization of crustacean biomass and also makes great efforts to develop safe and sustainable shrimp and crab shell waste management technologies.