Study On The Effect Of Oxygen-Containing Functional Groups On Carbon-based Fuel Gasification Process Based On Model Compounds

The carbon-based fuel gasification technology is a clean energy utilization method.Further improvement of gasification efficiency requires in-depth research on the gasification reaction mechanism of focusing.Oxygen-containing functional groups can improve the gasification activity of coal char,and a single variable study of the mechanism of action of oxygen-containing functional groups can be achieved through model compounds.Carbon-based fuels such as coal and biomass tend to be graphitized later in the pyrolysis process.In this paper,graphene oxide(GO)and highly oriented pyrolytic graphite(HOPG)are used as model compounds to study the effect of oxygen-containing functional groups on carbon-based fuel gasification.Different degrees of oxidation of GO were prepared by Hummers oxidation,and further carboxyl regulation was carried out.Different types and quantities of oxygencontaining functional groups were formed on the surface.The Fourier transform infrared spectrometer(FTIR)and X-ray photoelectron spectroscopy(XPS)were used.Characterization.A multi-stage micro-fluidized bed reaction system was used to study the GO gasification process with different oxygen-containing functional groups.Gasification gas products were analyzed by a process mass spectrometer to characterize the gasification reactivity of different samples.In the non-catalytic and catalytic gasification reactions,the addition of oxygen-containing functional groups can significantly increase the gasification reactivity of graphite,and the carboxylation treatment is particularly significant.By comparing the oxygen-containing functional group data obtained by FTIR and XPS tests,it is concluded that COC has little effect on the steam gasification reaction process.COOH is the most favorable oxygencontaining functional group for gasification reaction and not only improves the gasification reactivity.It also increases the gas production rate of H2,CO,and CO2 in the gasification process.The gasification process of HOPG and GO were carried out on a fixed-bed reaction system in a horizontal furnace,and characterized by scanning electron microscopy(SEM)and atomic force microscopy(AFM).The effect of oxygencontaining functional groups on the bulk diffusion of carbon was compared.During the gasification process,the bulk diffusion process of the carbon matrix is also affected by the oxygen-containing functional groups.The gasification of HOPG without oxygen-containing functional groups will be etched to form hexagonal pits and trenches.The mechanism of bulk diffusion of carbon is explained by SEM and AFM.Oxidized HOPG promotes the edge erosion of the gasification process due to the increase of sulfhydryl groups on the edge.Unlike HOPG etching,GO vaporizes by forming random etched holes.The oxygen-containing functional group destroys the hexagonal lattice structure of the carbon atom layer,so that the etching can no longer form a regular shape on the graphite lattice.Different catalysts,temperatures,and gasification agents can lead to the formation of different types and sizes of etched holes.The etching under the same conditions on the coke will also form a pore structure,demonstrating the rationality of the research methods for model compounds.