Based on the analysis of material motion in the axial direction, heat transfer and mass transport processes in a rotary kiln, and combining with pulverized coal combustion, material pyrogenation, cooling of furnace wa...Based on the analysis of material motion in the axial direction, heat transfer and mass transport processes in a rotary kiln, and combining with pulverized coal combustion, material pyrogenation, cooling of furnace wall finally, and heat transfer and mass transport equations, the combined heat transfer mathematical model for alumina rotary kiln was built up. According to the in-site real operation parameters, the heat transfer mathematical model was solved numerically for an alumina rotary kiln to predict the temperature profiles of gas and material in the axial direction. The results show that as the excess air coefficient reduces from 1.38 to 1.20, the temperature of the sintering zone increases and the length decreases. However, as the excess air coefficient reduces from 1.20 to 1.10, the temperature of the sintering zone decreases and the length increases. When the mixed coal amount at the end of kiln is reduced from 68.6 kg/t to 62.0 kg/t and the burned coal amount at the head of kiln correspondingly increases from 155.3 kg/t to 161.9 kg/t, the sintering zone temperature increases and the length reduces. The suitable excess air coefficient and mixed coal amount at the end of kiln are recommended for the rotary kiln operation optimization.展开更多
Seven diaryl ethers were synthesized with potassium fluoride coated alumina as a strong base and the addition of catalytic amount of PTC. The yield of diaryl ethers with addition of PTC was much higher than that witho...Seven diaryl ethers were synthesized with potassium fluoride coated alumina as a strong base and the addition of catalytic amount of PTC. The yield of diaryl ethers with addition of PTC was much higher than that without PTC.A discussion of the catalysis mechanism was given in this paper.展开更多
Tb3+ doped boro-alumina-silicate glasses were synthesized in air by high temperature process. Optical absorption, emission and excitation spectra of the glasses have been measured. Effect of concentration quenching on...Tb3+ doped boro-alumina-silicate glasses were synthesized in air by high temperature process. Optical absorption, emission and excitation spectra of the glasses have been measured. Effect of concentration quenching on the lifetime and fluorescence yield of 5D3 and 5D4 level has been discussed. The absorption spectrum shows four poor peaks in the UV-Vis region. With excitation at 377 nm, the fluorescence spectrum of the sample has four major emission bands at 488, 542, 584 and 621 nm, which correspond to the 5D4→7Fj (j=6, 5, 4, 3) transitions respectively. The emission from the 5D3→7Fj (j=5, 4, 3) transitions around 415, 437 and 458 nm are very feeble. When Tb3+ concentration beyond a particular value (2%, mole fraction), the concentration quenching phenomenon of 5D3 state occurred, due to the dipole-dipole interaction among the Tb3+. The energy transfer process (5D3+7F6→5D4+7F0) leads to a high quenching concentration (up to 20%) of 5D4 state. The lifetime of 5D4 level in boro-alumina-silicate glass is about 3ms that can be used for new type of long-lasting phosphorescence device.展开更多
Mixed solld solutions magnesium-alumina spinel catalyst, MgAl2O4 ·xAl2O3·yMgO (0< x<9, 0< y <5), using to reduce the SOx emission from the fluid catalytic cracking units (FCCU), were prepared by ...Mixed solld solutions magnesium-alumina spinel catalyst, MgAl2O4 ·xAl2O3·yMgO (0< x<9, 0< y <5), using to reduce the SOx emission from the fluid catalytic cracking units (FCCU), were prepared by coprecipitation method. It was found that a "volcano" type curve relation between the lattice parameter (a) and the composition of the spinel existed. The activity decreases as the value of x in the alumina excess spinel increases from 1 to 9, and increases as the value of y increases in the magnesium-rich spinel until up to 1, if y >1, the activity decreases which was due to MgO and spinel coekist in the catalyst. The results of reduction-oxidation (red-ox) cycle tests showed that introducing rare earth cerium to spinel could improve the de-SOx activity. Of all the catalysts, 0.1Ce/MgAl2O4· MgO is a promising catalyst which has the highest activity.30% propane as reducing gas is superior to 30% H2.展开更多
基金Project(11C26214202599) supported by the SME Technology Innovation Fund of Ministry of Science and Technology,China
文摘Based on the analysis of material motion in the axial direction, heat transfer and mass transport processes in a rotary kiln, and combining with pulverized coal combustion, material pyrogenation, cooling of furnace wall finally, and heat transfer and mass transport equations, the combined heat transfer mathematical model for alumina rotary kiln was built up. According to the in-site real operation parameters, the heat transfer mathematical model was solved numerically for an alumina rotary kiln to predict the temperature profiles of gas and material in the axial direction. The results show that as the excess air coefficient reduces from 1.38 to 1.20, the temperature of the sintering zone increases and the length decreases. However, as the excess air coefficient reduces from 1.20 to 1.10, the temperature of the sintering zone decreases and the length increases. When the mixed coal amount at the end of kiln is reduced from 68.6 kg/t to 62.0 kg/t and the burned coal amount at the head of kiln correspondingly increases from 155.3 kg/t to 161.9 kg/t, the sintering zone temperature increases and the length reduces. The suitable excess air coefficient and mixed coal amount at the end of kiln are recommended for the rotary kiln operation optimization.
文摘Seven diaryl ethers were synthesized with potassium fluoride coated alumina as a strong base and the addition of catalytic amount of PTC. The yield of diaryl ethers with addition of PTC was much higher than that without PTC.A discussion of the catalysis mechanism was given in this paper.
基金Trans-Century Training Programme Foundation for the Talents by the Ministry of EducationNatural Science Fund of Jiangsu Province (BK2004121)the Innovation Foundation for Graduate Students of Jiangsu Province
文摘Tb3+ doped boro-alumina-silicate glasses were synthesized in air by high temperature process. Optical absorption, emission and excitation spectra of the glasses have been measured. Effect of concentration quenching on the lifetime and fluorescence yield of 5D3 and 5D4 level has been discussed. The absorption spectrum shows four poor peaks in the UV-Vis region. With excitation at 377 nm, the fluorescence spectrum of the sample has four major emission bands at 488, 542, 584 and 621 nm, which correspond to the 5D4→7Fj (j=6, 5, 4, 3) transitions respectively. The emission from the 5D3→7Fj (j=5, 4, 3) transitions around 415, 437 and 458 nm are very feeble. When Tb3+ concentration beyond a particular value (2%, mole fraction), the concentration quenching phenomenon of 5D3 state occurred, due to the dipole-dipole interaction among the Tb3+. The energy transfer process (5D3+7F6→5D4+7F0) leads to a high quenching concentration (up to 20%) of 5D4 state. The lifetime of 5D4 level in boro-alumina-silicate glass is about 3ms that can be used for new type of long-lasting phosphorescence device.
文摘Mixed solld solutions magnesium-alumina spinel catalyst, MgAl2O4 ·xAl2O3·yMgO (0< x<9, 0< y <5), using to reduce the SOx emission from the fluid catalytic cracking units (FCCU), were prepared by coprecipitation method. It was found that a "volcano" type curve relation between the lattice parameter (a) and the composition of the spinel existed. The activity decreases as the value of x in the alumina excess spinel increases from 1 to 9, and increases as the value of y increases in the magnesium-rich spinel until up to 1, if y >1, the activity decreases which was due to MgO and spinel coekist in the catalyst. The results of reduction-oxidation (red-ox) cycle tests showed that introducing rare earth cerium to spinel could improve the de-SOx activity. Of all the catalysts, 0.1Ce/MgAl2O4· MgO is a promising catalyst which has the highest activity.30% propane as reducing gas is superior to 30% H2.
