Partially or fully regenerated catalytic cracking catalysts were prepared by gasifying the coke deposited on coked catalysts with a gaseous mixture of oxygen and steam in a fixed fluidized bed （FFB）. The resultant s...Partially or fully regenerated catalytic cracking catalysts were prepared by gasifying the coke deposited on coked catalysts with a gaseous mixture of oxygen and steam in a fixed fluidized bed （FFB）. The resultant samples were characterized by different methods such as the nitrogen adsorption-desorption analysis, the X-ray diffractometry, the infrared spectroscopy, the ammonia temperature-programmed desorption （NH3-TPD） method, the X-ray fluorescence （XRF） analysis, the transmission electron microscopy and energy dispersive X-ray spectroscopy （TEM-EDX）, the thermal-gravimetric analysis （TGA） and the differential thermal analysis （DTA）. The results showed that exposure of catalyst to steam for about 10 minutes at temperature ≥ 800 ℃ could not cause too much destruction of the catalysts, and an amount of coke equating to about 0.27 m% was enough to block approximately all acid sites in micro-pores of the zeolite catalyst. Coke didn＇t show equal reactivity during coke burning-off that could be accelerated by the catalytic action of nearby metal atoms. However, when the carbon content on the catalyst reached about 2.44 m%, the catalytic action of metals on the catalyst was not evident. The severe thermal and hydrothermal environment during exposure of the catalyst to steam at a temperature in the range of about 860--880 ℃ for 30 minutes could lead to collapse of pore structure and transformation of crystal phase and consequently decrease of the surface area and acid amount on the catalyst.展开更多
Ga-Al-MFI samples were synthesized in hydrothermal conditions from gels of composition 1.08CH3NH2- 0.134TPABr-1SiO2-xAl2O3-yGa2O3-40H2O at 175 ℃ for 7 days, with x = 0.005 and 0.0025, y = 0.005, 0,010 and 0.020. The ...Ga-Al-MFI samples were synthesized in hydrothermal conditions from gels of composition 1.08CH3NH2- 0.134TPABr-1SiO2-xAl2O3-yGa2O3-40H2O at 175 ℃ for 7 days, with x = 0.005 and 0.0025, y = 0.005, 0,010 and 0.020. The samples were characterized by XRD, BET measurements, thermal analysis （TGA-DTA） atomic absorption and high resolution solid state MAS 27Al and 71Ga NMR measurements. The aromatization of propane was studied as catalytic test. The activity and selectivity of the catalysts were determined for benzene, toluene and xylenes on the one hand and for methane and ethane on the other hand. The most active sample was obtained with the highest Ga/AI ratio. For this sample, the BTX selectivity obtained by aromatization was always higher than the hydrocracking selectivity leading to methane and ethane. The relative amount of toluene was higher than that of benzene and ofxylenes. The samples were deactivated by coke formation that was revealed more severe for the most active sample,展开更多
PASCA, ESR and Microreactor, have been used to study the states and properties of coking deposits on catalyst. The results indicate that the C exists as three types of states on catalyst surface. The first and second ...PASCA, ESR and Microreactor, have been used to study the states and properties of coking deposits on catalyst. The results indicate that the C exists as three types of states on catalyst surface. The first and second types of carbon are the main reason of the catalyst deactivation, but the third type has a promoting role in n-C_7 hydrocracking reaction. The S_s-C interacts strongly with catalyst, forming metal-carbon-support interaction (MCSI).展开更多
A composite material（Fe3O4/Coke）using coke supported Fe3O4 magnetic nanoparticles was successfully prepared via an in-situ chemicaloxidation precipitation method and characterized by SEM,XRD,Raman,and FTIR.The resul...A composite material（Fe3O4/Coke）using coke supported Fe3O4 magnetic nanoparticles was successfully prepared via an in-situ chemicaloxidation precipitation method and characterized by SEM,XRD,Raman,and FTIR.The results showed that the Fe3O4 nanoparticles existed steadily on the surface of coke,with better dispersing and smaller particle size.The catalytic ability of Fe3O4/Coke were investigatied by degrading p-nitrophenol（P-NP）.The results showed that the apparent rate constant for the P-NP at 1.0 g·L^-1 catalyst,30 mmol·L^-1 H2O2,pH=3.0,30 ℃ and the best ratio of Coke/Fe3O4 0.6,was evaluated to be 0.027 min^-1,the removalrate of CODCr was 75.47%,and the dissolubility of Fe was 2.42 mg·L^-1.Compared with pure Fe3O4,the catalytic ability of Fe3O4/Coke in the presence of H2O2 was greatly enhanced.And Fe3O4/Coke was a green and environmentalcatalyst with high catalytic activity,showing a good chemicalstability and reusability.展开更多
文摘Partially or fully regenerated catalytic cracking catalysts were prepared by gasifying the coke deposited on coked catalysts with a gaseous mixture of oxygen and steam in a fixed fluidized bed （FFB）. The resultant samples were characterized by different methods such as the nitrogen adsorption-desorption analysis, the X-ray diffractometry, the infrared spectroscopy, the ammonia temperature-programmed desorption （NH3-TPD） method, the X-ray fluorescence （XRF） analysis, the transmission electron microscopy and energy dispersive X-ray spectroscopy （TEM-EDX）, the thermal-gravimetric analysis （TGA） and the differential thermal analysis （DTA）. The results showed that exposure of catalyst to steam for about 10 minutes at temperature ≥ 800 ℃ could not cause too much destruction of the catalysts, and an amount of coke equating to about 0.27 m% was enough to block approximately all acid sites in micro-pores of the zeolite catalyst. Coke didn＇t show equal reactivity during coke burning-off that could be accelerated by the catalytic action of nearby metal atoms. However, when the carbon content on the catalyst reached about 2.44 m%, the catalytic action of metals on the catalyst was not evident. The severe thermal and hydrothermal environment during exposure of the catalyst to steam at a temperature in the range of about 860--880 ℃ for 30 minutes could lead to collapse of pore structure and transformation of crystal phase and consequently decrease of the surface area and acid amount on the catalyst.
基金supported by MIUR PRIN 2010–2011 2010H7PXLC Project on“Innovative downstream processing of conversion of algal biomass for the production of jet fuel and green diesel”
文摘Ga-Al-MFI samples were synthesized in hydrothermal conditions from gels of composition 1.08CH3NH2- 0.134TPABr-1SiO2-xAl2O3-yGa2O3-40H2O at 175 ℃ for 7 days, with x = 0.005 and 0.0025, y = 0.005, 0,010 and 0.020. The samples were characterized by XRD, BET measurements, thermal analysis （TGA-DTA） atomic absorption and high resolution solid state MAS 27Al and 71Ga NMR measurements. The aromatization of propane was studied as catalytic test. The activity and selectivity of the catalysts were determined for benzene, toluene and xylenes on the one hand and for methane and ethane on the other hand. The most active sample was obtained with the highest Ga/AI ratio. For this sample, the BTX selectivity obtained by aromatization was always higher than the hydrocracking selectivity leading to methane and ethane. The relative amount of toluene was higher than that of benzene and ofxylenes. The samples were deactivated by coke formation that was revealed more severe for the most active sample,
文摘PASCA, ESR and Microreactor, have been used to study the states and properties of coking deposits on catalyst. The results indicate that the C exists as three types of states on catalyst surface. The first and second types of carbon are the main reason of the catalyst deactivation, but the third type has a promoting role in n-C_7 hydrocracking reaction. The S_s-C interacts strongly with catalyst, forming metal-carbon-support interaction (MCSI).
基金Funded by the Specialized Research Fund for Doctoral Program of Higher Education of China(No.20114219110002)the Educational Department of Hubei Province of China(No.D20131107)the Natural Science Fundation of Hubei Provice(No.2014CFB810)
文摘A composite material（Fe3O4/Coke）using coke supported Fe3O4 magnetic nanoparticles was successfully prepared via an in-situ chemicaloxidation precipitation method and characterized by SEM,XRD,Raman,and FTIR.The results showed that the Fe3O4 nanoparticles existed steadily on the surface of coke,with better dispersing and smaller particle size.The catalytic ability of Fe3O4/Coke were investigatied by degrading p-nitrophenol（P-NP）.The results showed that the apparent rate constant for the P-NP at 1.0 g·L^-1 catalyst,30 mmol·L^-1 H2O2,pH=3.0,30 ℃ and the best ratio of Coke/Fe3O4 0.6,was evaluated to be 0.027 min^-1,the removalrate of CODCr was 75.47%,and the dissolubility of Fe was 2.42 mg·L^-1.Compared with pure Fe3O4,the catalytic ability of Fe3O4/Coke in the presence of H2O2 was greatly enhanced.And Fe3O4/Coke was a green and environmentalcatalyst with high catalytic activity,showing a good chemicalstability and reusability.
