Pyrolysis of aquatic carbohydrates using CO2 as reactive gas medium: A case study of chitin

Abstract

Here in this study, the thermolysis of aquatic biopolymer (i.e., chitin) was mainly investigated as a strategic means for reinforcing the insecure supply chains of terrestrial biomass. To maximize carbon utilization in the carbon substrate and establish a sustainable pyrolysis platform, this study particularly employed CO2 as reactive gas medium. To this end, this study laid great emphasis on elucidating the mechanistic role of CO2 in pyrolysis of chitin. For the fundamental study, the thermolysis of chitin in CO2 in reference to the case in N2 was characterized thermo-gravimetrically. A series of the TGA tests signified that the homogeneous reactions between solid-state chitin and CO2 should be excluded. However, a lab-scale pyrolysis of chitin in CO2 demonstrated that CO2 enhanced thermal cracking of the volatile hydrocarbon species from the thermolysis of chitin. In parallel, CO2 reacted with the volatile hydrocarbon species to form CO. To justify such genuine mechanistic roles of CO2, two-stage pyrolysis of chitin was conducted, and all experimental findings strongly supported the genuine mechanistic roles of CO2.