Study On Preparation Of Carbon Materials By Catalytic Co-pyrolysis Of Biomass And Polyvinyl Chloride

Pyrolysis technology is considered to be a potential thermochemical treatment technology for solid wastes,and has broad application prospects in protecting the environment and recycling resources.Based on the characteristics of the main components of the solid waste components,this paper divides them into biomass,plastics,etc.A typical solid waste is selected from each type,and a series of experimental studies on pyrolysis characteristics and pyrolysis process conditions are performed.Research,including:1.The pyrolysis characteristics of single-component samples of polyvinyl chloride were investigated by thermogravimetric analysis.The pyrolysis process of PVC is relatively complex and can be roughly divided into two stages: the first stage is mainly the removal of HCl;the second stage is mainly the breaking of the multi-olefin chain to form various polycyclic aromatic hydrocarbons,and the amount of pyrolysis residue is about7.3%.The pyrolysis mechanism is mainly the reaction of removal of hydrogen chloride and cyclization of conjugated olefins.2.Using copper-aluminum-based hydrotalcite as a catalyst,thermogravimetric analysis was used to study the catalytic pyrolysis characteristics of polyvinyl chloride.The results show that Cu Al Layered Double Hydroxide as a catalyst can significantly reduce the degradation temperature of polyvinyl chloride,effectively absorb HCl,inhibit the breakage of molecular chains,promote the cross-linking reaction between molecules and form more carbon.the mass ratio of Cu Al Layered Double Hydroxide is 5% of the mass of polyvinyl chloride,which can significantly improve its catalytic performance and maximize the yield of carbide.3.Exploring the process conditions for pyrolysis and carbonization of polyvinylchloride using thermogravimetric analysis and tube furnace experiments.The process conditions of polyvinyl chloride carbonization are: the mass ratio of Cu Al Layered Double Hydroxide is 5% of the mass of polyvinyl chloride;the vacuum atmosphere(vacuum degree ?0.08 MPa);the heating rate ?20?/min;the temperature of low-temperature carbonization section is 300?,the carbonation maintain time of the section is 90 min;the temperature of the high temperature carbonization section is 600?,and the carbonization maintain time of the section is 60 min.4.The pyrolysis and carbonization experiments of polyvinyl chloride by the above process conditions show that the carbide yield of polyvinyl chloride is obviously improved after the optimized carbonization process,and the carbon content in the carbide is significantly improved,and the carbide is increased.The structure has also been improved,carbon content is 82.17%.5.Thermogravimetric analysis was performed to study the co-pyrolysis characteristics of pine wood powder and polyvinyl chloride / copper-aluminum hydrotalcite.The results show that because of the hemicellulose in the pine wood powder,the thermal decomposition temperature is relatively low,and acidic substances are first generated during co-pyrolysis.These acidic substances have initiated the thermal decomposition process of polyvinyl chloride / copper aluminum hydrotalcite.This reduces the co-pyrolysis temperature.During the pyrolysis process,the cellulose and hemicellulose pyrolysis temperature ranges of pine are similar to those of the PVC pyrolysis dechlorination stage.Interaction occurs during co-pyrolysis.The released hydrogen chloride can catalyze the dehydration reaction of cellulose.It also has a catalytic effect on the thermal decomposition and carbon formation of lignin.From the perspective of carbide yield,co-pyrolysis of pine wood powder and PVC improved coke yield,about 10%.