The influence of a pre-oxidation process on the chemical properties of crushed bituminous coal and on adsorption properties of the subsequently formed char and activated carbon is discussed in this paper. Datong bitum...The influence of a pre-oxidation process on the chemical properties of crushed bituminous coal and on adsorption properties of the subsequently formed char and activated carbon is discussed in this paper. Datong bituminous coal samples sized 6 mm were oxidized at different temperatures and for different times and then carbonized and activated by steam to obtain activated carbons. A Uniform Design method was used to arrange the experiments,IR and adsorption experiments were used to characterize these oxidized coals,chars and activated carbon samples. The results show that the carboxyl group disappeared and α-CH2 groups joined to alkenes decreased dramatically but the carbonyl group clearly increased in the coal sample oxidized at 543 K; The chemical composition of coal samples oxidized at lower temperature is different from that of coal oxidized at 543 K. Oxidizing coal samples at higher temperatures for a short time or at lower temperatures for a longer time resulted in activated carbon samples that tended toward the same adsorption properties: Iodine number 1100 mg/g and Methylene blue value 252 mg/g. The yield of activated carbon obtained from the pre-oxidized coal is 10% higher than the yield from parent coal but the activated carbons have the same adsorption properties.展开更多
The chemical structure evolution of coal,which is important for understanding coalification and the accompanying volatile and possible oil generation,is generally thought to be influenced by temperature,time and confi...The chemical structure evolution of coal,which is important for understanding coalification and the accompanying volatile and possible oil generation,is generally thought to be influenced by temperature,time and confining pressure.Though evidence concerning the impacts of stress on the chemical structure has accumulated for many years and some hypotheses have been proposed,the mechanism remains controversial.Recent years have seen a breakthrough in mechanochemistry,which proves that stress can act on the molecule directly to initiate or accelerate reactions by deforming the chemical bonds.The progress in mechanochemistry gives researchers incentive to consider how stress works on the chemical structure of coals.Preliminary quantum chemical calculations have been performed on the macromolecule of anthracite to explain the mechanism of gas generation during the deformation experiments at low temperatures.This paper briefly reviews the evidence regarding the impacts of stress on the chemical structure of coals and introduces the recent achievements in the mechanism research.To further investigate this problem,more work should be undertaken by researchers from both geology and quantum chemistry fields.展开更多
基金Project 50204011 supported by the National Natural Science Foundation of China
文摘The influence of a pre-oxidation process on the chemical properties of crushed bituminous coal and on adsorption properties of the subsequently formed char and activated carbon is discussed in this paper. Datong bituminous coal samples sized 6 mm were oxidized at different temperatures and for different times and then carbonized and activated by steam to obtain activated carbons. A Uniform Design method was used to arrange the experiments,IR and adsorption experiments were used to characterize these oxidized coals,chars and activated carbon samples. The results show that the carboxyl group disappeared and α-CH2 groups joined to alkenes decreased dramatically but the carbonyl group clearly increased in the coal sample oxidized at 543 K; The chemical composition of coal samples oxidized at lower temperature is different from that of coal oxidized at 543 K. Oxidizing coal samples at higher temperatures for a short time or at lower temperatures for a longer time resulted in activated carbon samples that tended toward the same adsorption properties: Iodine number 1100 mg/g and Methylene blue value 252 mg/g. The yield of activated carbon obtained from the pre-oxidized coal is 10% higher than the yield from parent coal but the activated carbons have the same adsorption properties.
基金supported by the National Key Research and Development Program of China(2016YFC0600401)the National Natural Science Foundation of China(41030422)
文摘The chemical structure evolution of coal,which is important for understanding coalification and the accompanying volatile and possible oil generation,is generally thought to be influenced by temperature,time and confining pressure.Though evidence concerning the impacts of stress on the chemical structure has accumulated for many years and some hypotheses have been proposed,the mechanism remains controversial.Recent years have seen a breakthrough in mechanochemistry,which proves that stress can act on the molecule directly to initiate or accelerate reactions by deforming the chemical bonds.The progress in mechanochemistry gives researchers incentive to consider how stress works on the chemical structure of coals.Preliminary quantum chemical calculations have been performed on the macromolecule of anthracite to explain the mechanism of gas generation during the deformation experiments at low temperatures.This paper briefly reviews the evidence regarding the impacts of stress on the chemical structure of coals and introduces the recent achievements in the mechanism research.To further investigate this problem,more work should be undertaken by researchers from both geology and quantum chemistry fields.
