Study On The Kinetics And Mechanism Of Biomass Pyrolysis Catalyzed By Ternary Lithium Battery Cathode Wast

As the only renewable carbon source,the resource utilization of biomass can not only reduce the consumption of traditional fossil raw materials but also release the pressure of energy and environmental problems.However,due to the complicated preparation process of biomass products and the disadvantages of high oxygen content,and strong acidity of the products produced,biomass cannot directly replace fossil energy in modern internal combustion engines.The quality of bio-oil produced by different pyrolysis processes varies greatly,and based on this characteristic the modification and upgrading of bio-oil becomes the main direction of this study.In this study,we mainly studied the effects of recycled cathode materials for spent lithium-ion battery cathode on the pyrolysis characteristics,pyrolysis kinetics,and distribution of pyrolysis products of lignocellulose components,nitrogen-containing biomass,and then realized the biochar modified by recovering metal elements of the cathode materials,study their catalytic pyrolysis effects on cellulose and waste express cardboard.The main conclusions of the study include:The recovery of spent lithium-ion battery cathode was studied,and different treatment methods（one-step method:direct mixing method,two-step method:impregnation-drying method）were investigated to add cathode materials to biomass（lignin,cellulose,chitin,chitosan）,to explore its effect on biomass pyrolysis properties.It was shown that the samples treated by the two-step method（BC2）are rich in transition metals,which can effectively reduce the content of anhyrosugars and increase the content of ketones produced during the pyrolysis of cellulose;promote the conversion of lignin-derived phenols into hydrocarbons and aliphatic compounds;BC2 also promotes the cleavage of glycosidic,C-O and C-C bonds,thus promoting the thermal decomposition of chitin to acetamido acetaldehyde.In addition,the calculation based on the Coats-Redfern method showed that the addition of BC2 significantly reduced the apparent activation energy required for biomass pyrolysis reactions,and the apparent activation energy of cellulose was reduced from 86.7 k J/mol to 68.7 k J/mol after the addition of BC2.The biochar is prepared by chemical activation method,and the acid-leaching solution is prepared by dissolving the cathode materials with H₃PO₄and HCl,respectively,and the biochar was modified to study its structural characteristics and catalytic effect.The research shows that the biochar modified by the H₃PO₄ acid leaching solution has a higher specific surface area(S_BET:907.36 m²/g).HCl is a better solvent for dissolving BC.The concentration of metal ions in its acid-leaching solution is higher than that in its H₃PO₄acid-leaching solution,and the maximum content of Mn is about 3500mg/L.Comparing different models by Coats-Redfern method,R² was maximum when Frist-order（O1）model was chosen,indicating that the pyrolysis reaction of cellulose was controlled by chemical reactions.The addition of biochar catalysts significantly improves the conversion of anhydrosugars to hydrocarbons during pyrolysis,especially char-Cl,which enhances the conversion of light oxygenated components（e.g.aldehyde）and furans to hydrocarbons.The biochar（char 2）modified by HCl acid leaching solution was prepared,and the effects of the addition of cathode and char 2 on the pyrolysis characteristics of cellulose and waste express cardboard and the distribution of pyrolysis products were studied.This investigation showed that the pyrolysis curves of cellulose and cardboard were very similar.Using the Coats-Redfern method in comparison with the DAEM calculation results,both concluded that the addition of char 2 could reduce the apparent activation energy required for the reaction and improve the efficiency of pyrolysis.Char 2 reduces the oxygen content of the product and promotes the conversion of anhydrosugars,ketones,and aldehydes into hydrocarbons during pyrolysis.