Techno-Economic and Life Cycle Assessment of Carboxylated Cellulose Nanocrystals Production on Industrial Scale

Abstract

Cellulose nanocrystals are an attractive biobased alternative to partially replace fossil-based components due to their attractive properties, such as biocompatibility, biodegradability, and mechanical properties. Proposed applications include composite reinforcements, biomedical applications, and packaging solutions. A novel semicontinuous industrial-scale process for the production of carboxylated cellulose nanocrystals (c-CNCs) has been designed. The process is based on HCl gas hydrolysis, followed by TEMPO oxidation. The capacity of the plant is 8 kt/a of c-CNCs (per dry matter), where the final product is a 1 wt % solution. The recycling of the hydrogen chloride gas utilized in the hydrolysis is implemented in the process. Experimental testing shows that conventional industrial equipment can be utilized for the purification of the product and dispersion into c-CNCs. A techno-economic analysis of the process shows that the minimum selling price would be 4.3 €/kg per dry matter. The global warming potential of the c-CNC process was estimated to be 1705 kg CO2e/t c-CNCs based on the impact category used in standard EN15804 + A2. The process puts forward a serious candidate for the state-of-the-art technology that produces sulfated CNCs by hydrolysis in aqueous sulfuric acid.