The pyrolysis kinetics of three different kinds of fresh biomass (grass: triple A, wheat straw, corn straw) in nitrogen flow were studied by thermogravimetric analysis at five different heating rates. The kinetic para...The pyrolysis kinetics of three different kinds of fresh biomass (grass: triple A, wheat straw, corn straw) in nitrogen flow were studied by thermogravimetric analysis at five different heating rates. The kinetic parameters of the pyrolysis process were calculated using the method of Ozawa-Flynn-Wall and the mechanism of reactions were investi- gated using the method of Popescu. It was found that the values of activation energy varied in different temperature ranges. The pyrolysis processes are well described by the models of Zhuravlev (Zh) and valid for diffusion-controlled between 200 ℃ and 280 ℃, by Ginstling-Brounshtein (G-B), valid for diffusion-control between 280 ℃ and 310 ℃, for first-order chemical reaction between 310℃ and 350 ℃, by Zhuravlev (Zh) valid for diffusion-control between 350 ℃ and 430 ℃ and by the one-way transport model when temperatures are over 430 ℃.展开更多
By using the advanced instrumentation of a Computer Controlled Scanning Electron Microscope （CCSEM）, X-ray diffraction （XRD） and X-ray fluorescence （XRF）, the ash composition and the mineral components of six ty...By using the advanced instrumentation of a Computer Controlled Scanning Electron Microscope （CCSEM）, X-ray diffraction （XRD） and X-ray fluorescence （XRF）, the ash composition and the mineral components of six typical Huainan coals of different origins were studied. The transformation of mineral matter at high temperatures was tracked by XRD in reducing conditions. The quartz phase decreased sharply and the anorthite content tended to increase at first and then decreased with increasing temperatures. The formed mullite phase reached a maximum at 1250 ℃ but showed a tendency of slow decline when the temperature was over 1250 ℃. The mullite formed in the heating process was the main reason of the high ash melting temperature of Huainan coals. Differences in peak intensity of mullite and anorthite reflected differences in phase concentration of the quenched slag fractions, which contributed to the differences in ash melting temperatures. The differences in the location of an mnorphous hump maximum indicated differences of glass types which may affect ash melting temperatures. For Huainan coal samples with relatively high ash melting tempera- tures, the intensity of the diffraction lines for mullite under reducing condition is high while for the samples with relatively low ash melting temperature the intensity for anorthite is high.展开更多
基金Foreign Excellent Young Talents in Foreign Universities(gxgwfx2019013)China Postdoctoral Science Foundation Project(2018M632519)+1 种基金National key basic research development program(973 Program)(2014CB238901)National Natural Science Foundation of China(E041102)。
基金Project 50474056 supported by the National Natural Science Foundation of China
文摘The pyrolysis kinetics of three different kinds of fresh biomass (grass: triple A, wheat straw, corn straw) in nitrogen flow were studied by thermogravimetric analysis at five different heating rates. The kinetic parameters of the pyrolysis process were calculated using the method of Ozawa-Flynn-Wall and the mechanism of reactions were investi- gated using the method of Popescu. It was found that the values of activation energy varied in different temperature ranges. The pyrolysis processes are well described by the models of Zhuravlev (Zh) and valid for diffusion-controlled between 200 ℃ and 280 ℃, by Ginstling-Brounshtein (G-B), valid for diffusion-control between 280 ℃ and 310 ℃, for first-order chemical reaction between 310℃ and 350 ℃, by Zhuravlev (Zh) valid for diffusion-control between 350 ℃ and 430 ℃ and by the one-way transport model when temperatures are over 430 ℃.
基金Projects 2003001 supported by the key project of Huainan city, & 2004kj125 by the Science Funding of Department of Education of Anhui Province
文摘By using the advanced instrumentation of a Computer Controlled Scanning Electron Microscope （CCSEM）, X-ray diffraction （XRD） and X-ray fluorescence （XRF）, the ash composition and the mineral components of six typical Huainan coals of different origins were studied. The transformation of mineral matter at high temperatures was tracked by XRD in reducing conditions. The quartz phase decreased sharply and the anorthite content tended to increase at first and then decreased with increasing temperatures. The formed mullite phase reached a maximum at 1250 ℃ but showed a tendency of slow decline when the temperature was over 1250 ℃. The mullite formed in the heating process was the main reason of the high ash melting temperature of Huainan coals. Differences in peak intensity of mullite and anorthite reflected differences in phase concentration of the quenched slag fractions, which contributed to the differences in ash melting temperatures. The differences in the location of an mnorphous hump maximum indicated differences of glass types which may affect ash melting temperatures. For Huainan coal samples with relatively high ash melting tempera- tures, the intensity of the diffraction lines for mullite under reducing condition is high while for the samples with relatively low ash melting temperature the intensity for anorthite is high.
