The utilization of fossil fuels causes serious negative impacts on the environment and human life. To mitigate greenhouse gases and other pollutants, a novel combustion process-the nonflame combustion technology with ...The utilization of fossil fuels causes serious negative impacts on the environment and human life. To mitigate greenhouse gases and other pollutants, a novel combustion process-the nonflame combustion technology with a thermal cyclic carrier of molten salt is introduced. In this technology, a whole combustion is divided into two steps, i.e., the section of producing oxide and the section of combustion. In the first step, oxygen is separated from air, and pure N_2 is simultaneously formed which is easily recovered. In the other step, the fuels react with lattice oxygen in the oxides formed in the first step, and at the same time, thermal energy, CO_2 and H_2O vapor are produced. It is noted that the CO_2 is easily separated from water vapor and ultimately captured. Theoretically, there are no environmental-unfriendly gases such as CO_2, NO_x and SO_2 discharged in the whole combustion process. Some metal oxides scattered into molten salts play the roles of oxygen carriers in the combustion system, and they can constantly charge and discharge oxygen element from air to fuels during the combustion process. A nonflame combustion system with Li_2CO_3+K_2CO_3+Na_2SO_4 as the molten salt system, CH_4 as the fuel and CuO as the catalyst was experimentally investigated. The experimental results show that the combustion process proceeded as it was theoretically analyzed, and CO_2 with a high volume fraction of 77.0%_95.0% and N_2 with a high volume fraction of 91.9%_99.3% were obtained. The high concentration of CO_2 is favorable for capturing and storing subsequently. Therefore, the potential of reducing CO_2 emissions of this nonflame combustion technology is huge.展开更多
The thermal expansion behavior of La1-xSrxMn1-yCoyO3-δ (x=0.2-0.4, y=0.1-0.3) perovskites in air has been investigated. The average linear thermal expansion coefficients increased with increasing Sr content up to 40 ...The thermal expansion behavior of La1-xSrxMn1-yCoyO3-δ (x=0.2-0.4, y=0.1-0.3) perovskites in air has been investigated. The average linear thermal expansion coefficients increased with increasing Sr content up to 40 mole fraction or Co content up to 30 mole fraction. The expansion is generally attributed to an increase in the average cation radius as some of the cations in the perovskite are reduced in valence when oxygen ions are removed from the structure.展开更多
Effects of heat treatment temperature and time on hardness and wear resistance of RE-Ni-W-P-SiC-PTFE and RE-Ni-W-P-SiC composite coatings were studied. The results indicated that the hardness of the composite coatings...Effects of heat treatment temperature and time on hardness and wear resistance of RE-Ni-W-P-SiC-PTFE and RE-Ni-W-P-SiC composite coatings were studied. The results indicated that the hardness of the composite coatings as-deposited was lower and the mass loss (i.e. rate of abrasion) was higher, while the hardness increased and the rate of abrasion decreased with the increase of heat treatment temperature. The rate of abrasion was the lowest and hardness was the highest at 400℃. The hardness decreased and the rate of abrasion increased with the temperature increasing continuously. Both the hardness and wear resistance also increased with the prolongation of heat treatment time, reaching their peak values when the heat treatment time was 2 h. The experimental results also showed that the hardness of the coatings decreased with PTFE quantity enhancing, but the wear rate diminished correspondingly. X-ray diffraction analysis indicated that the structure of RE-Ni-W-P-SiC-PTFE composite coating as-deposited is amorphous, and it partly became crystal when heat treatment temperature was over 300℃.展开更多
A new chromium-free conversion film was obtained on surface of a ZnAl alloy by chemical conversion process. Influence of the additives in treating solution containing cerium salt on the corrosion protection of the con...A new chromium-free conversion film was obtained on surface of a ZnAl alloy by chemical conversion process. Influence of the additives in treating solution containing cerium salt on the corrosion protection of the conversion film formed on zinc alloy was investigated. Corrosion tests and electrochemical measurements in sodium chloride solution were performed . The microstructure and composition of the coatings were examined by means of SEM, EDS and XRD. It was found that the corrosion protection capabilities of the conversion film are markedly increased with the cerium nitride plus additives (hydrogen fluoride acid and an organic inhibitor) treating process. The modified conversion film is an organic/inorganic composite coating and is much more corrosion resistant than the conventional chromate conversion coating and the single cerium conversion coating.展开更多
基金Supported by the National Natural Science Foundation of China(No.5 0 16 4 0 0 2 ) and Science & Technology Foundationof Baoshan Iron and Steel Co.L td
文摘The utilization of fossil fuels causes serious negative impacts on the environment and human life. To mitigate greenhouse gases and other pollutants, a novel combustion process-the nonflame combustion technology with a thermal cyclic carrier of molten salt is introduced. In this technology, a whole combustion is divided into two steps, i.e., the section of producing oxide and the section of combustion. In the first step, oxygen is separated from air, and pure N_2 is simultaneously formed which is easily recovered. In the other step, the fuels react with lattice oxygen in the oxides formed in the first step, and at the same time, thermal energy, CO_2 and H_2O vapor are produced. It is noted that the CO_2 is easily separated from water vapor and ultimately captured. Theoretically, there are no environmental-unfriendly gases such as CO_2, NO_x and SO_2 discharged in the whole combustion process. Some metal oxides scattered into molten salts play the roles of oxygen carriers in the combustion system, and they can constantly charge and discharge oxygen element from air to fuels during the combustion process. A nonflame combustion system with Li_2CO_3+K_2CO_3+Na_2SO_4 as the molten salt system, CH_4 as the fuel and CuO as the catalyst was experimentally investigated. The experimental results show that the combustion process proceeded as it was theoretically analyzed, and CO_2 with a high volume fraction of 77.0%_95.0% and N_2 with a high volume fraction of 91.9%_99.3% were obtained. The high concentration of CO_2 is favorable for capturing and storing subsequently. Therefore, the potential of reducing CO_2 emissions of this nonflame combustion technology is huge.
基金This work was supported by the National Naturel Science Foundation of China(No.600740i9).
文摘The thermal expansion behavior of La1-xSrxMn1-yCoyO3-δ (x=0.2-0.4, y=0.1-0.3) perovskites in air has been investigated. The average linear thermal expansion coefficients increased with increasing Sr content up to 40 mole fraction or Co content up to 30 mole fraction. The expansion is generally attributed to an increase in the average cation radius as some of the cations in the perovskite are reduced in valence when oxygen ions are removed from the structure.
文摘Effects of heat treatment temperature and time on hardness and wear resistance of RE-Ni-W-P-SiC-PTFE and RE-Ni-W-P-SiC composite coatings were studied. The results indicated that the hardness of the composite coatings as-deposited was lower and the mass loss (i.e. rate of abrasion) was higher, while the hardness increased and the rate of abrasion decreased with the increase of heat treatment temperature. The rate of abrasion was the lowest and hardness was the highest at 400℃. The hardness decreased and the rate of abrasion increased with the temperature increasing continuously. Both the hardness and wear resistance also increased with the prolongation of heat treatment time, reaching their peak values when the heat treatment time was 2 h. The experimental results also showed that the hardness of the coatings decreased with PTFE quantity enhancing, but the wear rate diminished correspondingly. X-ray diffraction analysis indicated that the structure of RE-Ni-W-P-SiC-PTFE composite coating as-deposited is amorphous, and it partly became crystal when heat treatment temperature was over 300℃.
文摘A new chromium-free conversion film was obtained on surface of a ZnAl alloy by chemical conversion process. Influence of the additives in treating solution containing cerium salt on the corrosion protection of the conversion film formed on zinc alloy was investigated. Corrosion tests and electrochemical measurements in sodium chloride solution were performed . The microstructure and composition of the coatings were examined by means of SEM, EDS and XRD. It was found that the corrosion protection capabilities of the conversion film are markedly increased with the cerium nitride plus additives (hydrogen fluoride acid and an organic inhibitor) treating process. The modified conversion film is an organic/inorganic composite coating and is much more corrosion resistant than the conventional chromate conversion coating and the single cerium conversion coating.
