Study On Pyrolysis Characteristics Of Distillers Grains Solid Waste And Preparation Of Activated Carbon

With the development of social economy and the improvement of living standard,people pay more and more attention to environmental pollution.At the same time,with the increasing demand for energy,fossil energy can no longer meet the needs of the current social development,so it is imperative to explore the development of green ne w energy to replace fossil fuels.Biomass resources are abundant and widely distributed,it is a promising clean and renewable energy.And China produces a lot of waste distillers'grains every year,Distiller's grains is an important by-product in the brewing industry and the alcohol industry,and it is also a biomass resource.Due to the high water content of distiller's grains,a large amount of distiller's grains leachate will be produced during the stacking process,and the distiller's grains leachate contains a large amount of organic pollutants.If stored improperly or not handled in time,it will cause serious environmental pollution.It is an important subject related to ecological civilization,environmental protection and energy utilization to explore the disposal technology of vinasse waste volume reduction,harmlessness and recycling.To this end,this article takes distiller's grains waste as the research object,and deeply discusses the pyrolysis weightlessness characteristics,activation energy,gas phase product infrared evolution characteristics of distiller's grains and distiller's grains residues after extraction of non-lignocellulose components,proteins in distiller's grains and other components The interaction with the lignocellulose component in distiller's grains during the pyrolysis process and the reaction mechanism of the process provide a new technical route and theoretical guidance for the thermal treatment of distiller's grain solid wastes,and proposes to use distiller's grains a s the carbonized raw material and K₂CO₃ as Activator's"one-step chemical activation method"to prepare distiller's grains activated carbon preparation process.First,this article uses the SDT650 thermogravimetric analyzer to study the pyrolysis weight loss characteristics of distiller's grains and distiller's grains after separation of non-lignocellulosic components.The results show that the pyrolysis reaction of distillers grains is divided into three stages,the first stage is 50-138^oC,the second stage is138-500^oC,and the third stage is 500-900^oC.The second stage is the main stage of pyrolysis of distillers grains,with the maximum pyrolysis rate at 305^oC.With the increase of heating rate,the pyrolysis weight loss curve of vinasse gradually moves to the high temperature side,the initial pyrolysis temperature increases,the weight loss rate per unit time gradually increases,and the maximum pyrolysis weight loss rate increases.The thermogravimetric-infrared spectroscopy combined equipment?TG-FTIR?was used to study the evolution characteristics of pyrolysis gas products and functional groups with the pyrolysis reaction.The pyrolysis kinetic reaction model was established,and the protein components and distillers grains in distillers grains were analyzed.Interaction law of middle lignocellulose components during pyrolysis.TG-FTIR analysis results show that the main reactions occurring in the pyrolysis of distiller's grains are Maillard reaction,ketonization reaction and decarboxylation reaction,and pyrolysis volatiles are mainly divided into inorganic gas components?such as H₂O,CH₄,CO₂?and organic groups Points?such as amines,aldehydes,ketones,acids,phenols?.Protein and amino acids promote the pyrolysis of lignocellulose in a certain temperature range.When the pyrolysis temperature is T<230^oC and T>380^oC,it produces an inhibitory effect,and when 230^oC<T<380^oC,it produces an promoting effect.The presence of non-lignocellulose components leads to a higher reaction rate and lower activation energy?150 k J/mol?in the lower temperature range than distiller's grains residue?200 k J/mol?.Then using distiller's grain waste as raw material,the distiller's grains activated carbon activated by K₂CO₃,KOH,KHCO₃,CH₃COOK respectively were studied.It was found that K₂CO₃ activated distiller's grains activated carbon had the largest methylene blue adsorption capacity,and KHCO3 activated distiller's grains activated carbon had the largest specific surface area.It is 2321.375 m²/g;the pore volume of activated charcoal activated by CH₃COOK is the smallest.The factors affecting the adsorption performance of activated carbon from distillers grains are arranged as follows:total pore volume>mesopores>surface area.Finally,using K₂CO₃ as the activator,the"one-step chemical activation method"was used to prepare distiller's grains activated carbon.By optimizing the preparation process,the best preparation conditions are as follows:the carbonization temperature is 850^oC,the carbonization time is 1 h,the mass ratio of vinasse to K₂CO₃ is 1:1,and the heating rate is15^oC/min.The pore structure of the obtained activated carbon is mainly micropores and mesopores.The maximum pore size is 348.2 nm,the average pore size is 3.0895 nm,the specific surface area is 1946 m²/g,the total pore volume is 1.503 cm³/g,and the adsorption capacity for methylene blue is 843 mg/g.In the initial stage of the adsorption of methylene blue,the adsorption rate is faster.When the adsorption time is 20 mi n,the adsorption reaches equilibrium.