Study On Tobacco Stem Pyrolysis Carbonization Characteristics

In the world energy consumption list,biomass is the world's second largest after the three fossil energy,ranked fourth in energy.Because it is directly or indirectly derived from the green plants on the earth's photosynthesis,therefore,biomass energy is a renewable energy,inexhaustible.In the context of the depletion of traditional energy,biomass energy has gradually become the alternative to the three fossil energy the best energy.At the same time,biomass pyrolysis technology is a popular biomass treatment technology,it can transform rich low-grade biomass energy into high-quality chemical products for chemical production.To strengthen the development and utilization of biomass pyrolysis technology is conducive to the full use of rich biomass energy,is conducive to promoting social economic development,and is significant for the global sustainable development.In this paper,tobacco stem was selected as the experimental raw material,proposing the use of pyrolysis carbonization technology to deal with tobacco stem,so the stem pyrolysis was carried out three aspects:Firstly,the TG,DTG and DSC curves of the pyrolysis of the tobacco stem at different heating rates were obtained by thermogravimetric experiment.The general trend index D was calculated by analyzing the change trend of the thermogravimetric curve.The pyrolysis process and the heating rate The effects of pyrolysis on the pyrolysis process were studied by using the three classical mathematical methods of Coats-Redfern,Flynn-Wall-Ozawa,and Kissinger method.The activation energies and pre-exponential factors of the pyrolysis process were obtained.At the same time,it is proved that the activation energy and the pre-exponential factors in the pyrolysis process of the tobacco stem are still linearly complementary,that is to say,there is a dynamic compensation effect between the activation energies and the pre-exponential factors.Secondly,the pyrolysis experiments were carried out on the tobacco stem under different working conditions.The microscopic morphology,microstructure parameters and element migration were studied under the experimental conditions?pyrolysis temperature,particle size,pyrolysis time,N₂ purge rate and treatment process?.SEM and specific surface area and pore size analysis were used to characterize the microstructure of tobacco stem.EDS and XRD were used to characterize the migration of elements,The lower the pyrolysis temperature,the larger the particle size,the longer the pyrolysis time,the more favorable the enrichment of the carbon element,and the theoretical basis for the application of the pyrolysis carbonization technology.Finally,the activating mechanism of steam activation and activation o f NaOH were discussed as an example of physical and chemical activation.It was proved that steam activation and alkali activation were beneficial to the formation of micropores and increase the specific surface area The Based on the study of the effect of activator dosage,activation temperature and activation time on the yield of activated carbon and the specific surface area of tobacco stem,the optimum technological parameters of pyrolysis activation were obtained.