Shenmu(SM)subbituminous coal without caking property was treated by low-temperature rapid pyrolysis(LTRP)to modify its caking and coking properties.The treated samples were characterized by Fourier transform infrared ...Shenmu(SM)subbituminous coal without caking property was treated by low-temperature rapid pyrolysis(LTRP)to modify its caking and coking properties.The treated samples were characterized by Fourier transform infrared spectrometry,vitrinite reflectance,and X-ray diffraction to determine the modification mechanism.Moreover,caking index(G)and coking indices(mechanical strength,coke reactivity,and coke strength after reaction)were employed to evaluate caking and coking properties,respectively.The results showed that SM coal was gradually upgraded with increasing processing temperature.Furthermore,the G values for the treated samples were significantly higher than that for SM coal,and G reached the maximum value at 450℃,implying the modification of caking property and the existence of an optimum temperature(450℃).Additionally,laboratory coking determinations showed that LTRP increased the mechanical strength of coke and coke strength after reaction and decreased coke reactivity when the treated coals were used in the coal blends instead of raw SM coal.Overall,LTRP treatment is effective to improve the caking and coking properties of SM coal.A mechanism was proposed for the modification.Suitable upgrading degree with suitable molecular masses and some releasable hydrogen-rich donor species present within the coal,which dominate the development of caking property,is important.展开更多
Production of high-strength carbonized coal composites from non-caking coals only with possible application as coke is presented.A binder and a non-caking coal were mixed in different ratios and carbonized at 1000C t...Production of high-strength carbonized coal composites from non-caking coals only with possible application as coke is presented.A binder and a non-caking coal were mixed in different ratios and carbonized at 1000C to produce coal-binder composites.Two binders,one from coal origin and other from oil origin were used.Effect of coal-binder mixing ratio and base coal particle size on the fracture strength of composites was investigated.Bonding of binder with the coal particles at coal-binder interface and development of connected carbon matrix were primarily responsible for the strength of the carbonized coal composites.The trend of change in fracture strength as a function of coal-binder fraction was similar for both the binders.However,for same coal-binder mixing ratio,binder type strongly affected the maximum strength achieved.Fracture strength was found to be primarily dependent on the coal-binder mixing ratio and base coal particle size.The main finding of this study is that the irrespective of binder type,for a given base coal particle size there was only one coal-binder mixing ratio at which the maximum strength was obtained.The binder fraction at which the highest strength observed was correlated to the carbon matrix connectivity index.展开更多
基金The authors are grateful to the National Natural Science Foundation of China(No.21776002)Natural Science Foundation of Anhui Provincial Education Department(Nos.KJ2016A097 and KJ2017A056)+1 种基金Innovation Project of Overseas People of Anhui Province,Student Research Training Program of Anhui Province(201810360190)Youth Natural Science Foundation of Anhui University of Technology(No.QZ201806)for financial support.
文摘Shenmu(SM)subbituminous coal without caking property was treated by low-temperature rapid pyrolysis(LTRP)to modify its caking and coking properties.The treated samples were characterized by Fourier transform infrared spectrometry,vitrinite reflectance,and X-ray diffraction to determine the modification mechanism.Moreover,caking index(G)and coking indices(mechanical strength,coke reactivity,and coke strength after reaction)were employed to evaluate caking and coking properties,respectively.The results showed that SM coal was gradually upgraded with increasing processing temperature.Furthermore,the G values for the treated samples were significantly higher than that for SM coal,and G reached the maximum value at 450℃,implying the modification of caking property and the existence of an optimum temperature(450℃).Additionally,laboratory coking determinations showed that LTRP increased the mechanical strength of coke and coke strength after reaction and decreased coke reactivity when the treated coals were used in the coal blends instead of raw SM coal.Overall,LTRP treatment is effective to improve the caking and coking properties of SM coal.A mechanism was proposed for the modification.Suitable upgrading degree with suitable molecular masses and some releasable hydrogen-rich donor species present within the coal,which dominate the development of caking property,is important.
文摘Production of high-strength carbonized coal composites from non-caking coals only with possible application as coke is presented.A binder and a non-caking coal were mixed in different ratios and carbonized at 1000C to produce coal-binder composites.Two binders,one from coal origin and other from oil origin were used.Effect of coal-binder mixing ratio and base coal particle size on the fracture strength of composites was investigated.Bonding of binder with the coal particles at coal-binder interface and development of connected carbon matrix were primarily responsible for the strength of the carbonized coal composites.The trend of change in fracture strength as a function of coal-binder fraction was similar for both the binders.However,for same coal-binder mixing ratio,binder type strongly affected the maximum strength achieved.Fracture strength was found to be primarily dependent on the coal-binder mixing ratio and base coal particle size.The main finding of this study is that the irrespective of binder type,for a given base coal particle size there was only one coal-binder mixing ratio at which the maximum strength was obtained.The binder fraction at which the highest strength observed was correlated to the carbon matrix connectivity index.
