Hydrodesulfurization(HDS)of coal tar pitch(CTP)using Pt/Al_(2)O_(3)and Pd/Al_(2)O_(3)catalysts in tetrahydrofuran at 333 K and atmospheric pressure was investigated.The HDS of dibenzothiophene(DBT)proceeded over both ...Hydrodesulfurization(HDS)of coal tar pitch(CTP)using Pt/Al_(2)O_(3)and Pd/Al_(2)O_(3)catalysts in tetrahydrofuran at 333 K and atmospheric pressure was investigated.The HDS of dibenzothiophene(DBT)proceeded over both the Pt and Pd catalysts under the mild conditions.The effects of polycyclic aromatic hydrocarbons on the HDS of DBT were examined:a naphthalene ring suppressed the HDS,while a benzene ring did not.CTP underwent HDS as well as partial hydrogenation under the mild conditions.The Pt catalyst was more active than the Pd catalyst in the HDS of CTP.The sulfur content in CTP was reduced by over 50%through the HDS process.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
Catalytic coal gasification is an efficient way to achieve high conversion rates at low temperatures.Catalyst loss due to the reaction between the inherent mineral matter in the coal and the catalyst is a major hurdle...Catalytic coal gasification is an efficient way to achieve high conversion rates at low temperatures.Catalyst loss due to the reaction between the inherent mineral matter in the coal and the catalyst is a major hurdle for its practical application.The problem may be overcome by removing the mineral matter from the coal before use.Two demineralizing approaches,acid-washing and solvent-extraction methods are investigated for demineralizing the coals.Elemental analysis,XRD analysis,NMR analysis,and N_(2)adsorption analysis were made to compare the demineralization efficiency,crystallographic carbon microstructure,chemical structure,and micro-porosity,respectively.Solvent-extraction method was found be more efficient for demineralization.Difference was observed in the chemical structure and micro-porosity while crystallographic carbon-microstructure was found to be similar.Non-catalytic and catalytic gasification reactivity of the chars obtained by the two methods was compared.Gas composition and gas evolution profiles were also obtained and found to be influenced by the degree of demineralization.展开更多
文摘Hydrodesulfurization(HDS)of coal tar pitch(CTP)using Pt/Al_(2)O_(3)and Pd/Al_(2)O_(3)catalysts in tetrahydrofuran at 333 K and atmospheric pressure was investigated.The HDS of dibenzothiophene(DBT)proceeded over both the Pt and Pd catalysts under the mild conditions.The effects of polycyclic aromatic hydrocarbons on the HDS of DBT were examined:a naphthalene ring suppressed the HDS,while a benzene ring did not.CTP underwent HDS as well as partial hydrogenation under the mild conditions.The Pt catalyst was more active than the Pd catalyst in the HDS of CTP.The sulfur content in CTP was reduced by over 50%through the HDS process.
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.
文摘Catalytic coal gasification is an efficient way to achieve high conversion rates at low temperatures.Catalyst loss due to the reaction between the inherent mineral matter in the coal and the catalyst is a major hurdle for its practical application.The problem may be overcome by removing the mineral matter from the coal before use.Two demineralizing approaches,acid-washing and solvent-extraction methods are investigated for demineralizing the coals.Elemental analysis,XRD analysis,NMR analysis,and N_(2)adsorption analysis were made to compare the demineralization efficiency,crystallographic carbon microstructure,chemical structure,and micro-porosity,respectively.Solvent-extraction method was found be more efficient for demineralization.Difference was observed in the chemical structure and micro-porosity while crystallographic carbon-microstructure was found to be similar.Non-catalytic and catalytic gasification reactivity of the chars obtained by the two methods was compared.Gas composition and gas evolution profiles were also obtained and found to be influenced by the degree of demineralization.
