Characterization of physicochemical properties and techno-economic analysis of cellulose nanocrystals derived from pilot production of sweet potato residue

Cellulose nanocrystals (CNCs) have attracted great interest due to their unique structural characteristics and physical and chemical properties. However, their high production cost has limited their applications. This study aimed to achieve pilot-scale production of cellulose and CNCs using sweet potato residue (SPR) as the primary raw material. A systematic economic benefit comparison was also conducted, using commercial acid hydrolyzed wood as a benchmark. Results showed that the cellulose produced had a degree of polymerization of 475. CNCs produced from SPR cellulose exhibited a rod-like structure, with diameters ranging from 15.10 to 30.90 nm and lengths from 80.80 to 259.90 nm. The CNCs were found to be of type I cellulose structure with high crystallinity. The maximum thermal degradation temperature of CNCs was 347.88°C, and the zeta potential was -40.07 mV, indicating its suitability as a reinforcing material in environmental protection bio-composites. The total capital investment for producing commercial CNCs was $227.74 million, while the investment for CNCs from SPR was $203.34 million. The trial production of CNCs from SPR proved to be more financially profitable, with a higher net present value. The use of SPR provided both economic and environmental benefits, reducing fossil fuel dependency. These findings will contribute to the high-value utilization of agricultural by-products and the further development of CNCs composites.