The promotional effects of Zr on the structure, reduction, carburization and catalytic behavior of precipitated iron-based Fischer-Tropsch synthesis （FTS） catalysts were investigated. The catalysts were characterize...The promotional effects of Zr on the structure, reduction, carburization and catalytic behavior of precipitated iron-based Fischer-Tropsch synthesis （FTS） catalysts were investigated. The catalysts were characterized by N2 physisorption, temperature-programmed reduction （TPR）, and M6ssbauer effect spectroscopy （MES） techniques. As revealed by N2 physisorption, Zr decreased the BET surface area and pore volume of the catalyst. The results of TPR and MES show that Zr suppresses the reduction and carburization of Fe catalysts because of the interaction between Fe and Zr. The FTS reaction results indicate that Zr decreases the FTS activity of Fe catalysts but improves the catalysts＇ stability. In addition, Zr promoter restraines the formation of light hydrocarbons （methane and C2-C4） and shifts the production distribution to the heavy hydrocarbons.展开更多
The mathematic model of combined converter with two different flow modes of gas-cooled reactor was established. The effects of gas flow mode in gas-cooled reactor on combined converter was investigated with the yield ...The mathematic model of combined converter with two different flow modes of gas-cooled reactor was established. The effects of gas flow mode in gas-cooled reactor on combined converter was investigated with the yield of methanol was 1 400 kt/a. The results show that if the flow mode of the cooling pipe gas and the catalytic bed gas change from countercurrent to concurrent, the catalytic bed temperature distribution does not fit the most optimum temperature curve of reversible exothermic reaction and the heat duty of heat changer in whole process increased seriously, which means that there is much more equipment investment and more operating cost. The gas flow mode of gas-cooled reactor affects the methanol yield slightly. There- fore, the countercurrent gas flow mode of gas-cooled reactor is more lucrative in the combined converter process.展开更多
Using the lumping method, CH_4, C_3H_8, C_10H_22, and C_22H_44 were chosen as themodel products, and CO as the key component. The mathematical model of a gas-solidfluidized bed reactor was established based on some hy...Using the lumping method, CH_4, C_3H_8, C_10H_22, and C_22H_44 were chosen as themodel products, and CO as the key component. The mathematical model of a gas-solidfluidized bed reactor was established based on some hypotheses. The consumption kinetic model of CO was investigated, and the parameters were estimated by UniversalGlobal Optimization with the Marquardt method. Residual error distribution and a statisticaltest show that the intrinsic kinetic models are reliable and acceptable. A model of carbonchain growth probability was established in terms of experiments. Coupled with the Ander-son- Schulz-Flory (ASF) distribution, the amount of specific product could be obtained.Large- scale cold model experiments were conducted to investigate the distribution of thegas (solid) phase and determine the function of the voidage with the location of the catalytic bed. The change tendencies of the components in the catalytic bed at different temperatures were computed and figured out. The calculated value computed by the modelestablished for the Fe-based F-T synthesis catalyst fit the experimental value very wellunder the same operating conditions, and all the absolute values of the relative deviationsare less than 5%.展开更多
Mathematical simulation was performed on tube-shell reactor for dimethyl ether （DME） synthesis from coal-based syngas. The model was established based on kinetics of dimethyl-ether synthesis from syngas over a bifun...Mathematical simulation was performed on tube-shell reactor for dimethyl ether （DME） synthesis from coal-based syngas. The model was established based on kinetics of dimethyl-ether synthesis from syngas over a bifunctional catalyst, which is mixed by methanol synthesis catalyst and dehydration catalyst as 1：1 mass ratio. Methanol synthesis from CO and CO2 and methanol dehydration were selected as three-independent reactions, CO, CO2, and DME as key components to estab- lish the one-dimensional mathematical model of the reactor. The gas concentration and temperature profiles inside the reactor tubes were obtained. The operating conditions affecting DME synthesis were also discussed based on the model. The simula- tions indicate that higher pressure and lower temperature at the inlet and rich hydrogen in the reactant are favorable in direct DME synthesis in fixed-bed process, and the temperature of boiling water affect the reactor performance seriously.展开更多
文摘The promotional effects of Zr on the structure, reduction, carburization and catalytic behavior of precipitated iron-based Fischer-Tropsch synthesis （FTS） catalysts were investigated. The catalysts were characterized by N2 physisorption, temperature-programmed reduction （TPR）, and M6ssbauer effect spectroscopy （MES） techniques. As revealed by N2 physisorption, Zr decreased the BET surface area and pore volume of the catalyst. The results of TPR and MES show that Zr suppresses the reduction and carburization of Fe catalysts because of the interaction between Fe and Zr. The FTS reaction results indicate that Zr decreases the FTS activity of Fe catalysts but improves the catalysts＇ stability. In addition, Zr promoter restraines the formation of light hydrocarbons （methane and C2-C4） and shifts the production distribution to the heavy hydrocarbons.
文摘The mathematic model of combined converter with two different flow modes of gas-cooled reactor was established. The effects of gas flow mode in gas-cooled reactor on combined converter was investigated with the yield of methanol was 1 400 kt/a. The results show that if the flow mode of the cooling pipe gas and the catalytic bed gas change from countercurrent to concurrent, the catalytic bed temperature distribution does not fit the most optimum temperature curve of reversible exothermic reaction and the heat duty of heat changer in whole process increased seriously, which means that there is much more equipment investment and more operating cost. The gas flow mode of gas-cooled reactor affects the methanol yield slightly. There- fore, the countercurrent gas flow mode of gas-cooled reactor is more lucrative in the combined converter process.
基金Supported by the Doctoral Foundation of China (20050251006)
文摘Using the lumping method, CH_4, C_3H_8, C_10H_22, and C_22H_44 were chosen as themodel products, and CO as the key component. The mathematical model of a gas-solidfluidized bed reactor was established based on some hypotheses. The consumption kinetic model of CO was investigated, and the parameters were estimated by UniversalGlobal Optimization with the Marquardt method. Residual error distribution and a statisticaltest show that the intrinsic kinetic models are reliable and acceptable. A model of carbonchain growth probability was established in terms of experiments. Coupled with the Ander-son- Schulz-Flory (ASF) distribution, the amount of specific product could be obtained.Large- scale cold model experiments were conducted to investigate the distribution of thegas (solid) phase and determine the function of the voidage with the location of the catalytic bed. The change tendencies of the components in the catalytic bed at different temperatures were computed and figured out. The calculated value computed by the modelestablished for the Fe-based F-T synthesis catalyst fit the experimental value very wellunder the same operating conditions, and all the absolute values of the relative deviationsare less than 5%.
文摘Mathematical simulation was performed on tube-shell reactor for dimethyl ether （DME） synthesis from coal-based syngas. The model was established based on kinetics of dimethyl-ether synthesis from syngas over a bifunctional catalyst, which is mixed by methanol synthesis catalyst and dehydration catalyst as 1：1 mass ratio. Methanol synthesis from CO and CO2 and methanol dehydration were selected as three-independent reactions, CO, CO2, and DME as key components to estab- lish the one-dimensional mathematical model of the reactor. The gas concentration and temperature profiles inside the reactor tubes were obtained. The operating conditions affecting DME synthesis were also discussed based on the model. The simula- tions indicate that higher pressure and lower temperature at the inlet and rich hydrogen in the reactant are favorable in direct DME synthesis in fixed-bed process, and the temperature of boiling water affect the reactor performance seriously.
