CeO2-, La2O3-, and ZrO2-promoted Ni/Mg（Al）O catalysts synthesized by hydrotalcite-type precursors have been investigated with respect to catalytic activity and carbon formation in the hydrogenation and steam reformi...CeO2-, La2O3-, and ZrO2-promoted Ni/Mg（Al）O catalysts synthesized by hydrotalcite-type precursors have been investigated with respect to catalytic activity and carbon formation in the hydrogenation and steam reforming of toluene as a model tar compound. X-ray diffraction （XRD）, Brunauer-Emmett-Teller （BET） specific surface area and Hz-temperature programmed reduction （TPR） were used to observe the characteristics of the prepared catalysts. The carbon formation and its amount on the used catalysts were examined by transmission electron microscope （TEM）, scanning electron microscope （SEM） and thermogravimetric （TG）. The trend of catalytic activity as derived from the experimental results followed the order： Ni-Ce〉Ni-La〉Ni-Zr〉Ni. The catalyst modified with CeO2 exhibited the highest catalytic performance and had good carbon resistance in the hydrogenation and steam reforming of toluene. A toluene conversion of 96.8%, a CH4 yield of 45.2% and a CO yield of 50.4% have been achieved. The addition of promoters led to better dispersion of nickel species and higher interaction nickel-support, which were favorable for increasing the catalytic activity and effectively preventing carbon formation.展开更多
This paper proposes a new Predictive Direct Power Control(P-DPC) solution for three-phase grid-connected inverters, which combines direct power control strategy with the predictive control strategy and space vector pu...This paper proposes a new Predictive Direct Power Control(P-DPC) solution for three-phase grid-connected inverters, which combines direct power control strategy with the predictive control strategy and space vector pulse width modulation(SVPWM), obtaining both high transient performance and a constant switching frequency. This control solution can achieve decoupling control for active and reactive power and an adjustable power factor. Meanwhile, the grid-connected current can approximately be sinusoidal. The feasibility and advantages of the control strategy are verified by the simulation and experiment compared with another existing P-DPC.展开更多
A precursor of BaCe0.5Zr0.4Y0. 1O3-α electrolytes was synthesized by the sol-gel method and sintered at temperature which were 150 - 250 ℃ lower than by solid state reaction. The AC impedance spectrums of electrolyt...A precursor of BaCe0.5Zr0.4Y0. 1O3-α electrolytes was synthesized by the sol-gel method and sintered at temperature which were 150 - 250 ℃ lower than by solid state reaction. The AC impedance spectrums of electrolytes were measured by AUTOLAB PGSTA30 electrochemical measuring device at different temperatures. The conductivities of the electrolytes are 1.62×10^-4 - 6.43×10^-3, 2.52×10^-5 - 3.73×10^-3S·cm^-1 in the temperature range of 350-800℃. The activity energies are 0.54 and 0.84 eV. At the same time BaCe0.9Y0.1O3-α was prepared by direct solid state reaction. The conductivity of BaCe0.9Y0.1O3-α is 1 × 10^-4- 4×10^-3 S·cm^-1 and the activation energy is 0.50 eV at the same condition. The results show that conduction of electrolyte prepared by sol-gel method is higher than the one by solid state reaction. As far as BaCe0.9Y0.1O3-α concerned, its conductivity of the Zr-substituted specimens is decreased.展开更多
基金supported by the National High Technology Research and Development Program of China (No.2006AA11A189)the Science and Technology Commission of Shanghai Municipality,China (Nos.0952nm01400 and 07DZ12036)
文摘CeO2-, La2O3-, and ZrO2-promoted Ni/Mg（Al）O catalysts synthesized by hydrotalcite-type precursors have been investigated with respect to catalytic activity and carbon formation in the hydrogenation and steam reforming of toluene as a model tar compound. X-ray diffraction （XRD）, Brunauer-Emmett-Teller （BET） specific surface area and Hz-temperature programmed reduction （TPR） were used to observe the characteristics of the prepared catalysts. The carbon formation and its amount on the used catalysts were examined by transmission electron microscope （TEM）, scanning electron microscope （SEM） and thermogravimetric （TG）. The trend of catalytic activity as derived from the experimental results followed the order： Ni-Ce〉Ni-La〉Ni-Zr〉Ni. The catalyst modified with CeO2 exhibited the highest catalytic performance and had good carbon resistance in the hydrogenation and steam reforming of toluene. A toluene conversion of 96.8%, a CH4 yield of 45.2% and a CO yield of 50.4% have been achieved. The addition of promoters led to better dispersion of nickel species and higher interaction nickel-support, which were favorable for increasing the catalytic activity and effectively preventing carbon formation.
基金supported by the national 863 program (2011AA050204)
文摘This paper proposes a new Predictive Direct Power Control(P-DPC) solution for three-phase grid-connected inverters, which combines direct power control strategy with the predictive control strategy and space vector pulse width modulation(SVPWM), obtaining both high transient performance and a constant switching frequency. This control solution can achieve decoupling control for active and reactive power and an adjustable power factor. Meanwhile, the grid-connected current can approximately be sinusoidal. The feasibility and advantages of the control strategy are verified by the simulation and experiment compared with another existing P-DPC.
文摘A precursor of BaCe0.5Zr0.4Y0. 1O3-α electrolytes was synthesized by the sol-gel method and sintered at temperature which were 150 - 250 ℃ lower than by solid state reaction. The AC impedance spectrums of electrolytes were measured by AUTOLAB PGSTA30 electrochemical measuring device at different temperatures. The conductivities of the electrolytes are 1.62×10^-4 - 6.43×10^-3, 2.52×10^-5 - 3.73×10^-3S·cm^-1 in the temperature range of 350-800℃. The activity energies are 0.54 and 0.84 eV. At the same time BaCe0.9Y0.1O3-α was prepared by direct solid state reaction. The conductivity of BaCe0.9Y0.1O3-α is 1 × 10^-4- 4×10^-3 S·cm^-1 and the activation energy is 0.50 eV at the same condition. The results show that conduction of electrolyte prepared by sol-gel method is higher than the one by solid state reaction. As far as BaCe0.9Y0.1O3-α concerned, its conductivity of the Zr-substituted specimens is decreased.
