Hydrothermal Gasification And Carbonization Of Cellulose Using Fe₃O₄as Catalyst

With the development of the society and the industry, energyshortages and environmental problems are becoming two major problemsthat we humans are facing need urgent attention to be solved. Manyattempt have been carried out to develop clean and renewable energyresource. Among all the optional alternative energy resources, H2hasbeen considered as the ideal substitute to the mineral energy among theenergy academic circles for being clean, renewable, and its high energydensity. Among many methods of producing H2, biomass hydrothermalgasification is convenient and requires relatively mild react condition, itcan be fed with industry and the agriculture wastes, it does not cost muchand it provides a way to produce H2and carbon materials at the sametime. Thus, biomass hydrothermal gasification is a new andenvironment-friendly method to produce H2with high biomassconversion ratio, has a promising development prospect.In order to search for new catalyst for biomass hydrothermalgasification that is with prominent catalysis behavior and lowmanufacture cost and to search for new method that allows higher biomass conversion ratio, with the inspiration of the works of theprecursors this paper use microcrystalline cellulose (represent rawbiomass materials) as the feed stock for hydrothermal gasification, and[Bmim]Cl and deionized water as solvents. We chose nano Fe3O4particles prepared using chemical coprecipitation method after elaboratestudy, and we discussed the possibility and influencing factors ofhydrothermal biomass gasification and carbonization at the same time.(1) Using FeCl3, FeSO4, NaOH and diluted sulphuric acid as rawmaterials, we synthetized nano Fe3O4particles as catalyst for thehydrothermal gasification through conventional chemical coprecipitationmethod. We proposed the novel one-step mixing method of the celluloseand the catalyst, brought the one-step mixing method and conventionalmilling mixing method into comparison, characterized the differentprecursors prepared by the two mixing methods using XRD and TEM,and evaluated the influence of the novel mixing method on biomasshydrothermal gasification.(2) The nano Fe3O4catalyst synthetized was used in the cellulosehydrothermal gasification experiments carried out with water and[BMIM]Cl-water as solvent. The influences of the dose of catalyst, doseof [BMIM]Cl, reaction duration and reaction temperature on the yield ofH2were studied, and the yield of H2during gasification under thedifferent solvents were brought into comparison. (3) The nano Fe3O4catalyst synthetized was used in the cellulosepyrolysis gasification experiments. The influences of the dose of catalyst,reaction duration and reaction temperature on the yield of H2werestudied, and the yield of H2during hydrothermal gasification using wateras solvent and the yield of H2during pyrolysis gasification were broughtinto comparison.(4) Microcrystalline cellulose was used as raw material for catalyzedhydrothermal biomass carbonization using water as solvent. Nano Fe3O4particles was used as the catalyst, but it also served as a part of thereagent and participated into the formation of the carbon materials, andfinally generated nano Fe2O3/carbon core-shell materials. The influencesof reaction duration on the generated carbon materials were studied, XRD,SEM and TEM were used for the characterization of the nanoFe2O3/carbon core-shell materials. The forming mechanism of thematerials were proposed after elaborate study and the applicationprospect of the materials in water purification, PEMFC, super capacitorand lithium battery was discussed.