Catalytic Charactertstics Of Supported Ni Catalyst For Hydrothermal Liquefaction Of Paper Aluminum Plastic Packaging Waste

Paper-plastic aluminum packaging materials are widely used in food,medicine and daily necessities packaging due to their high barrier properties,safety and hygiene,and ease of use.However,the resulting large amount of waste poses a serious threat to China’s urban ecological environment.In the context of energy constraints and environmental pollution,the conversion of paper-plastic aluminum packaging waste into bio-oil energy products through thermochemical conversion has become the focus of research.This paper uses hydrothermal liquefaction technology to study the oil production characteristics of Tetra Pak paper,plastic and aluminum packaging waste.The bio-oil produced by hydrothermal liquefaction has the problems of high oxygen content and poor heating value(HHV).Ni-xCe/CNTs and Ni-xCe/Al2O3 catalysts were prepared by the equal volume impregnation method.Using a batch reactor at 360℃,20 MPa,and a material concentration of 20 wt%,the two catalysts Ni:Ce ratio,temperature,reaction time on bio-oil yield,boiling point distribution,element distribution and bio-oil chemical composition were studied Influence and speculate on the underlying catalytic reaction mechanism.Finally,the reaction network of paper aluminum plastic liquefaction is constructed and the reaction kinetics is analyzed.The research results have important scientific theoretical significance and technical application value for the energy conversion of paper-plastic aluminum packaging waste.The results showed that when Ni-xCe/CNTs is used as the catalyst,the yield of bio-oil reaches the highest yield.When the Ce content is 5 wt%,it is 20.75 wt%.The atomic ratio of H/C decreases slightly with the increase of Ce content,but due to the decrease of O content and the increase of C content,O/C greatly decreases.The Ni-Ce/CNTs catalyst promotes the increase of the content of hydrocarbon s and esters in the bio-oil,and the decrease of the content of ketones and aldehydes.In addition,we also characterized the thermal stability of the solid residue and the surface morphology of the catalyst.When Ni-xCe/A12O3 is the catalyst,the bimetallic Ni-xCe/A12O3 catalyst has a better catalytic effect than the monometallic Ni/Al2O3 catalyst.The yield of bio-oil is highest when the Ce content is 3 wt%,reaching 19.47 wt%.When the Ce content is 5 wt%,the contents of kerosene and diesel are the highest,respectively 33.9 wt%and 35.4 wt%.Bimetallic Ni-xCe/A12O3 catalysts have higher bio-oil C and H content,and HHV has also increased.GC-MS analysis found that bio-oil products mainly consist of ketones,ester compounds and benzene derivatives.Through comparison,it is found that changing the carrier has little effect on the change of bio-oil production rate and chemical composition content.Using the reaction network,we established a quantitative kinetic model in which the paper(ie carbohydrate),polyethylene(PE)and aluminum(Al)in the Tetra Pak components decompose to form bio-oil,solid residues,water phase and gas phases product(AP+GP).And the experimental results were used to estimate the liquefaction parameters of Tetra Pak at different temperatures and times.The MATLAB optimization function is used to determine the rate constant of the model by minimizing the least square error between the experimental data and the calculated data.The results show that the model accurately captures the trends in the experimental data.The kinetic reaction rate constant indicates that the decomposition of carbohydrates,polyethylene and aluminum decomposes first into water-phase and gas-phase products,and then further into bio-oil.Among them,carbohydrates are the main contributors to the generation of water vapor.The kinetic parameters calculated by the model are used to explore the parameter space to predict the yield of liquefied products.The model predicts that the bio-oil yield is highest at a temperature of 360℃ and a reaction time of 50 min.Finally,in order to further illustrate the effect of each reaction rate constant on the formation of liquefied products,the sensitivity coefficient and reaction rate were used for analysis.