Study On Pyrolysis And Catalytic Co-pyrolysis Characteristics Of Spirulina And Waste Tires

As the fossil energy crisis and the greenhouse effect intensify,biomass is gaining widespread attention as an alternative energy source because of its carbon neutrality and renewable nature.To implement the action plan to reach the peak of carbon emission by2030.Optimize the industrial structure and energy structure;promote the clean and efficient use of coal,vigorously develop new energy;promote the development and application of new energy-saving and environmental protection technologies,equipment and products,cultivate and grow energy-saving and environmental protection industries,and promote the economical and efficient use of resources and other measures are imperative.Spirulina,as the third generation of biomass energy,has become a hot spot in renewable energy research due to its small footprint,short growth cycle and high lipid content,and has a wide application prospect because of its low price.In order to achieve more efficient resource utilization and get higher quality products,the research on pyrolysis of single pure samples is developing in the direction of mixed pyrolysis and catalytic pyrolysis.There are still gaps in the research on the mechanism and synergistic effect of the pyrolysis reaction of Spirulina at home and abroad,and further research is needed on the mechanism and synergistic effect of the mixed pyrolysis reaction between microalgae and solid waste.In this paper,we focus on the high-value utilization of spirulina and waste tires,further understand the characteristics of mixed pyrolysis and catalytic pyrolysis,explore the changes of pyrolysis parameters,product distribution patterns,formation causes and reaction mechanism combined with pyrolysis reaction kinetics under different mixing ratios and oxides,in order to provide new technical routes and theoretical references for the resource treatment of spirulina and waste tires.Firstly,the thermal weight loss behavior of spirulina and waste tires in pyrolysis and mixed pyrolysis was studied,and the parameters of pyrolysis characteristics were obtained experimentally by using thermal weight loss analysis technique with the help of fully automated thermal weight loss analyzer,the interaction law of spirulina and waste tires in the pyrolysis process was analyzed by experimentally obtaining the pyrolysis characteristic parameters and establishing the interaction measurement index of mixed samples.The results showed that,there are three main stages of pyrolysis between spirulina and waste tires:preheating and drying stage,pyrolysis stage and carbonization stage.In the mixed pyrolysis,the experimental results showed that when the blending ratio of waste tires increased from 30%to 70%,the starting temperature of pyrolysis increased from 275.5°C to331.3°C;the ending temperature increased from 822.2°C to 834.2°C;the mass residual rate increased from 26.89%to 30.73%.However,compared with the single sample pyrolysis with waste tires first,spirulina was able to act as a decomposition activator for waste tires and the efficiency of pyrolysis was improved.When the blending ratio of spirulina and waste tires was 7:3,all stages showed synergistic effects,with the positive synergistic effect being most obvious between 350 and 400°C.7:3 was the optimal ratio for the mixed pyrolysis of both.Secondly,three oxide（Al₂O₃,Mg O and Si O₂）additives were added to the pyrolysis and mixed pyrolysis reactions of spirulina with waste tires to obtain the pyrolysis characteristics parameters under different types/proportions of additives and to reveal the effect law of different types of additives on the pyrolysis.The results showed that no significant changes were observed in the three stages of pyrolysis of spirulina with waste tires.The addition of50%Mg O to the experimental samples could effectively reduce the mass residual rate and increase the yield of volatile products,but considering other relevant pyrolysis characteristics parameters 20%Mg O played the most positive effect on the mixed pyrolysis of spirulina and waste tires.Overall the catalytic effect,Mg O is greater than Al₂O₃ and Si O₂.Then,the pyrolysis product characteristics,the components and main product evolution behaviors of pyrolysis products and reaction pathways were examined online while the pyrolysis reactions of spirulina with waste tires at different blending ratios using rapid pyrolysis and gas chromatography-mass spectrometry.The results showed that the mixed pyrolysis of spirulina and waste tires helped to reduce the percentage of acids in the bio-oil from 23.49%to 4.161%in the single sample pyrolysis of spirulina,and the presence of spirulina also improved the decomposition rate of waste tires,obtained more hydrocarbons and benzenes,and increased the calorific value of the pyrolysis oil,further proving that the mixed pyrolysis of spirulina and waste tires has potential for development.Finally,the kinetic parameters of each experimental group were calculated by using Flynm-Wall-Ozawa model and Kissinger-Akahira-Sunose model,and the pyrolysis kinetic models of spirulina and waste tires were established.In the mixed pyrolysis,the average activation energy of 241.35k J/mol（243.35k J/mol）was the lowest when the mixing ratio of spirulina and waste tires was 3:7;the addition of Mg O in the catalytic pyrolysis could significantly reduce the activation energy of the pyrolysis reaction,and the mixing ratio of spirulina and waste tires was 7:3,which was 191.19 k J/mol（190.56 k J/mol）.Based on the study of the pyrolysis characteristics of spirulina and waste tires,a higher quality bio-oil can be obtained by adding a catalyst while mixing pyrolysis.It provides a basis for the use of microalgae biomass to obtain high-value products and the way of pyrolysis utilization of solid waste.