The addition of small amounts of ceria to Co/Al2O3 catalysts increases the turnover rate of the catalyst and C5+ selectivity in the Fischer-Tropsch synthesis. In this work, the amounts of ceria, the calcination tempe...The addition of small amounts of ceria to Co/Al2O3 catalysts increases the turnover rate of the catalyst and C5+ selectivity in the Fischer-Tropsch synthesis. In this work, the amounts of ceria, the calcination temperature, the temperature-programmed reduction (TPR), the temperature-programmed oxidation (TPO), and XRD are investigated. The results show that the addition of small amounts of ceria to Co/Al2O3 catalyst (Ce/Co≈1∶ 10 ～1∶ 7, atom) can increase the CO conversion and liquid yield, while the calcination temperature can control both the chain growth probability and CO conversion in a reverse trend. The TPR and TPO experiments show that small amounts of Ceria can improve the reducibility, but the amounts of carbon deposit increase, and two-type carbon deposition is found in the short-term reaction catalyst.展开更多
Catalytic conversion of synthesis gas （CO＋H2） into hydrocarbons, also known as Fischer-Tropsch （FT） synthesis, is a crucial reaction for the translbrmation of non-petroleum carbon resources such as coal, natural ...Catalytic conversion of synthesis gas （CO＋H2） into hydrocarbons, also known as Fischer-Tropsch （FT） synthesis, is a crucial reaction for the translbrmation of non-petroleum carbon resources such as coal, natural gas, shale gas, coal-bed gas and biogas, as well as biomass into liquid fuels and chemicals. Many factors can influence the catalytic behavior of a FT catalyst. This review highlights recent advances in understanding some key catalyst factors, including the chemical state of active phases, the promoters, the size and the microenvironment of active phase, which determine the CO conversion activity and the product selectivity, particularly the selectivity to C5 ＋ hydrocarbons.展开更多
The effects of Manganese （Mn） incorporation on a precipitated iron-based Fischer-Tropsch synthesis （FTS） catalyst were investigated using N2 physical adsorption, air differential thermal analysis （DTA）, H2 tempe...The effects of Manganese （Mn） incorporation on a precipitated iron-based Fischer-Tropsch synthesis （FTS） catalyst were investigated using N2 physical adsorption, air differential thermal analysis （DTA）, H2 temperature-programmed reduction （TPR）, and Mǒssbauer spectroscopy. The FTS performances of the catalysts were tested in a slurry phase reactor. The characterization results indicated that Mn increased the surface area of the catalyst, and improved the dispersion of （α-Fe2O3 and reduced its crystallite size as a result of the high dispersion effect of Mn and the Fe-Mn interaction. The Fe-Mn interaction also suppressed the reduction of （α-Fe2O3 to Fe3O4, stabilized the FeO phase, and （or） decreased the carburization degree of the catalysts in the H2 and syngas reduction processes. In addition, incorporated Mn decreased the initial catalyst activity, but improved the catalyst stability because Mn restrained the reoxidation of iron carbides to Fe3O4, and improved further carburization of the catalysts. Manganese suppressed the formation of CH4 and increased the selectivity to light olefins （C2-4^=）, but it had little effect on the selectivities to heavy （C5＋） hydrocarbons. All these results indicated that the strong Fe-Mn interaction suppressed the chemisorptive effect of the Mn as an electronic promoter, to some extent, in the precipitated iron-manganese catalyst system.展开更多
A series of iron-based Fischer-Tropsch synthesis （FTS） catalysts incorporated with Al2O3 binder were prepared by the combination of co-precipitation and spray drying technology. The catalyst samples were characteriz...A series of iron-based Fischer-Tropsch synthesis （FTS） catalysts incorporated with Al2O3 binder were prepared by the combination of co-precipitation and spray drying technology. The catalyst samples were characterized by using N2 physical adsorption, temperature-programmed reduction/desorption （TPR/TPD） and MSssbauer effect spectroscopy （MES） methods. The characterization results indicated that the BET surface area increases with increasing Al2O3 content and passes through a maximum at the Al2O3/Fe ratio of 10/100 （weight basis）. After the point, it decreases with further increase in Al2O3 content. The incorporation of Al2O3 binder was found to weaken the surface basicity and suppress the reduction and carburization of iron-based catalysts probably due to the strong K-Al2O3 and Fe-Al2O3 interactions. Furthermore, the H2 adsorption ability of the catalysts is enhanced with increasing Al2O3 content. The FTS performances of the catalysts were tested in a slurry-phase continuously stirred tank reactor （CSTR） under the reaction conditions of 260 ℃, 1.5 MPa, 1000 h^-1 and molar ratio of H2/CO 0.67 for 200 h. The results showed that the addition of small amounts of Al2O3 affects the activity of iron-based catalysts to a little extent. However, with further increase of Al2O3 content, the FTS activity and water gas shift reaction （WGS） activity are decreased severely. The addition of appropriate Al2O3 do not affect the product selectivity, but the catalysts incorporated with large amounts of Al2O3 have higher selectivity for light hydrocarbons and lower selectivity for heavy hydrocarbons.展开更多
Conversion of Fischer-Tropsch wax into high quality synthetic crude or finished transportation fuels such as premium diesel has been studied over the past 15 years within BP. Catalyst screening and selection was carri...Conversion of Fischer-Tropsch wax into high quality synthetic crude or finished transportation fuels such as premium diesel has been studied over the past 15 years within BP. Catalyst screening and selection was carried out in dedicated micro-reactors and pilot plants, whose designs are critical to the performance selection. Variation in catalyst composition and defining the gas to oil feed ratios with the operating temperature are a few of the parameters studied. Product selection and maximizing diesel yield combined with stability （catalyst life） were the ultimate drivers. The selected catalyst was then tested under commercial conditions in a dedicated 300 barrel per day demonstration plant. The products were also tested in engines to assess their combustion characteristics.展开更多
Co/SiO2 and zirconium promoted Co/Zr/SiO2 catalysts were prepared using dielectric-barrier discharge （DBD） plasma instead of the conventional thermal calcination method. Fischer-Tropseh Synthesis （FTS） performance...Co/SiO2 and zirconium promoted Co/Zr/SiO2 catalysts were prepared using dielectric-barrier discharge （DBD） plasma instead of the conventional thermal calcination method. Fischer-Tropseh Synthesis （FTS） performances of the catalyst were evaluated in a fixed bed reactor. The results indicated that the catalyst treated by DBD plasma shows the higher FTS activity and yield of heavy hydrocarbons as compared with that treated by the conventional thermal calcination method. Increase in CO conversion was unnoticeable on the Co/SiO2 catalyst, but significant on the Co/Zr/SiO2 catalyst, both prepared by DBD plasma. On the other hand, heavy hydrocarbon selectivity and chain growth probability （a value） were enhanced on all the catalysts prepared by the DBD plasma. In order to study the effect of the DBD plasma treatment on the FTS performance, the catalysts were characterized by N2-physisorption, H2-temperature programed reduction （H2-TPR）, H2-temperature- programmed desorption （H2-TPD） and oxygen titration, transmission electron microscope （TEM） and X-ray diffraction （XRD）. It was proved that, compared with the traditional calcination method, DBD plasma not only could shorten the precursor decomposition time, but also could achieve better cobalt dispersion, smaller Co304 cluster size and more uniform cobalt distribution. However, cobalt reducibility was hindered to some extent in the Co/SiO2 catalyst prepared by DBD plasma, while the zirconium additive prevented significantly the decrease in cobalt reducibility and increased cobalt dispersion as well as the FTS performance.展开更多
Carbon nanotube （CNT）-supported Ru nanoparticles with mean sizes ranging from 2.3 to 9.2 nm were prepared by different post-treatments and studied for Fischer-Tropsch （FT） synthesis. The effects of Ru particle siz...Carbon nanotube （CNT）-supported Ru nanoparticles with mean sizes ranging from 2.3 to 9.2 nm were prepared by different post-treatments and studied for Fischer-Tropsch （FT） synthesis. The effects of Ru particle size on catalytic behaviors were investigated at both shorter and longer contact times. At shorter contact time, where the secondary reactions were insignificant, the turnover frequency （TOF） for CO conversion was dependent on the mean size of Ru particles; TOF increased with the mean size of Ru particles from 2.3 to 6.3 nm and then decreased slightly. At the same time, the selectivities to C5＋ hydrocarbons increased gradually with the mean size of Ru particles up to 6.3 nm and then kept almost unchanged with a further increase in Ru particle size. At longer contact time, C10-C20 selectivity increased significantly at the expense of C21＋ selectivity, suggesting the occurrence of the selective hydrocracking of C21＋ to C10-C20 hydrocarbons.展开更多
Barium modified Co/Al2O3 catalysts were prepared by incipient wetness impregnation.The catalysts were characterized by XRD,TPD and DRIFTS.The catalytic activity for Fischer-Tropsch synthesis was measured in a continuo...Barium modified Co/Al2O3 catalysts were prepared by incipient wetness impregnation.The catalysts were characterized by XRD,TPD and DRIFTS.The catalytic activity for Fischer-Tropsch synthesis was measured in a continuously stirred tank reactor.It was found that small amounts of BaO（≤2 wt%） improved the cobalt reducibility,which led to more cobalt active sites on the catalyst surface,and then resulted in higher CO conversion and C5＋ selectivity.However,for the catalysts with high BaO loadings negative effects on the catalytic activity and selectivity for high hydrocarbons were observed because of low cobalt reducibility.展开更多
A systematic study was undertaken to investigate the effects of the manganese incorporation manner on the textural properties, bulk and surface phase compositions, reduction/carburization behaviors, and surface basici...A systematic study was undertaken to investigate the effects of the manganese incorporation manner on the textural properties, bulk and surface phase compositions, reduction/carburization behaviors, and surface basicity of an iron-based Fischer-Tropsch synthesis （FTS） catalyst. The catalyst samples were characterized by N2 physisorption, X-ray photoelectron spectroscopy （XPS）, H2 （or CO） temperature-programmed reduction （TPR）, CO2 temperature-programmed desorption （TPD）, and M5ssbauer spectroscopy. The FTS performance of the catalysts was studied in a slurry-phase continuously stirred tank reactor （CSTR）. The characterization results indicated that the manganese promoter incorporated by using the coprecipitation method could improve the dispersion of iron oxide, and decrease the size of the iron oxide crystallite. The manganese incorporated with the impregnation method is enriched on the catalyst＇s surface. The manganese promoter added with the impregnation method suppresses the reduction and carburization of the catalyst in H2, CO, and syngas because of the excessive enrichment of manganese on the catalyst surface. The catalyst added manganese using the coprecipitation method has the highest CO conversion （51.9%） and the lowest selectivity for heavy hydrocarbons （C12＋）.展开更多
文摘The addition of small amounts of ceria to Co/Al2O3 catalysts increases the turnover rate of the catalyst and C5+ selectivity in the Fischer-Tropsch synthesis. In this work, the amounts of ceria, the calcination temperature, the temperature-programmed reduction (TPR), the temperature-programmed oxidation (TPO), and XRD are investigated. The results show that the addition of small amounts of ceria to Co/Al2O3 catalyst (Ce/Co≈1∶ 10 ～1∶ 7, atom) can increase the CO conversion and liquid yield, while the calcination temperature can control both the chain growth probability and CO conversion in a reverse trend. The TPR and TPO experiments show that small amounts of Ceria can improve the reducibility, but the amounts of carbon deposit increase, and two-type carbon deposition is found in the short-term reaction catalyst.
基金the National Basic Research Program of China(No.2013CB933100)the National Natural Science Foundation of China(No.21173174,No.21161130522,No.21033006and No.20923004)the Program for Changjiang Scholars and Innovative Research Team in University(No.IRT1036)
文摘Catalytic conversion of synthesis gas （CO＋H2） into hydrocarbons, also known as Fischer-Tropsch （FT） synthesis, is a crucial reaction for the translbrmation of non-petroleum carbon resources such as coal, natural gas, shale gas, coal-bed gas and biogas, as well as biomass into liquid fuels and chemicals. Many factors can influence the catalytic behavior of a FT catalyst. This review highlights recent advances in understanding some key catalyst factors, including the chemical state of active phases, the promoters, the size and the microenvironment of active phase, which determine the CO conversion activity and the product selectivity, particularly the selectivity to C5 ＋ hydrocarbons.
基金Foundation item:the National Outstanding Young Scientists Foundation of China(20625620)the National Key Basic Research Program of China(973 Program,2007CB216401)+1 种基金the National Natural Science Foundation of China(20590360)the Natural Science Foundation of Shanxi Province(2006021014).
文摘The effects of Manganese （Mn） incorporation on a precipitated iron-based Fischer-Tropsch synthesis （FTS） catalyst were investigated using N2 physical adsorption, air differential thermal analysis （DTA）, H2 temperature-programmed reduction （TPR）, and Mǒssbauer spectroscopy. The FTS performances of the catalysts were tested in a slurry phase reactor. The characterization results indicated that Mn increased the surface area of the catalyst, and improved the dispersion of （α-Fe2O3 and reduced its crystallite size as a result of the high dispersion effect of Mn and the Fe-Mn interaction. The Fe-Mn interaction also suppressed the reduction of （α-Fe2O3 to Fe3O4, stabilized the FeO phase, and （or） decreased the carburization degree of the catalysts in the H2 and syngas reduction processes. In addition, incorporated Mn decreased the initial catalyst activity, but improved the catalyst stability because Mn restrained the reoxidation of iron carbides to Fe3O4, and improved further carburization of the catalysts. Manganese suppressed the formation of CH4 and increased the selectivity to light olefins （C2-4^=）, but it had little effect on the selectivities to heavy （C5＋） hydrocarbons. All these results indicated that the strong Fe-Mn interaction suppressed the chemisorptive effect of the Mn as an electronic promoter, to some extent, in the precipitated iron-manganese catalyst system.
基金The financial support from the National Natural Science Foundation of China (20590361)the National Outstanding Young Scientists Foundation of China (20625620)
文摘A series of iron-based Fischer-Tropsch synthesis （FTS） catalysts incorporated with Al2O3 binder were prepared by the combination of co-precipitation and spray drying technology. The catalyst samples were characterized by using N2 physical adsorption, temperature-programmed reduction/desorption （TPR/TPD） and MSssbauer effect spectroscopy （MES） methods. The characterization results indicated that the BET surface area increases with increasing Al2O3 content and passes through a maximum at the Al2O3/Fe ratio of 10/100 （weight basis）. After the point, it decreases with further increase in Al2O3 content. The incorporation of Al2O3 binder was found to weaken the surface basicity and suppress the reduction and carburization of iron-based catalysts probably due to the strong K-Al2O3 and Fe-Al2O3 interactions. Furthermore, the H2 adsorption ability of the catalysts is enhanced with increasing Al2O3 content. The FTS performances of the catalysts were tested in a slurry-phase continuously stirred tank reactor （CSTR） under the reaction conditions of 260 ℃, 1.5 MPa, 1000 h^-1 and molar ratio of H2/CO 0.67 for 200 h. The results showed that the addition of small amounts of Al2O3 affects the activity of iron-based catalysts to a little extent. However, with further increase of Al2O3 content, the FTS activity and water gas shift reaction （WGS） activity are decreased severely. The addition of appropriate Al2O3 do not affect the product selectivity, but the catalysts incorporated with large amounts of Al2O3 have higher selectivity for light hydrocarbons and lower selectivity for heavy hydrocarbons.
文摘Conversion of Fischer-Tropsch wax into high quality synthetic crude or finished transportation fuels such as premium diesel has been studied over the past 15 years within BP. Catalyst screening and selection was carried out in dedicated micro-reactors and pilot plants, whose designs are critical to the performance selection. Variation in catalyst composition and defining the gas to oil feed ratios with the operating temperature are a few of the parameters studied. Product selection and maximizing diesel yield combined with stability （catalyst life） were the ultimate drivers. The selected catalyst was then tested under commercial conditions in a dedicated 300 barrel per day demonstration plant. The products were also tested in engines to assess their combustion characteristics.
基金supported by the National Natural Science Foundation of China(No.21076151)
文摘Co/SiO2 and zirconium promoted Co/Zr/SiO2 catalysts were prepared using dielectric-barrier discharge （DBD） plasma instead of the conventional thermal calcination method. Fischer-Tropseh Synthesis （FTS） performances of the catalyst were evaluated in a fixed bed reactor. The results indicated that the catalyst treated by DBD plasma shows the higher FTS activity and yield of heavy hydrocarbons as compared with that treated by the conventional thermal calcination method. Increase in CO conversion was unnoticeable on the Co/SiO2 catalyst, but significant on the Co/Zr/SiO2 catalyst, both prepared by DBD plasma. On the other hand, heavy hydrocarbon selectivity and chain growth probability （a value） were enhanced on all the catalysts prepared by the DBD plasma. In order to study the effect of the DBD plasma treatment on the FTS performance, the catalysts were characterized by N2-physisorption, H2-temperature programed reduction （H2-TPR）, H2-temperature- programmed desorption （H2-TPD） and oxygen titration, transmission electron microscope （TEM） and X-ray diffraction （XRD）. It was proved that, compared with the traditional calcination method, DBD plasma not only could shorten the precursor decomposition time, but also could achieve better cobalt dispersion, smaller Co304 cluster size and more uniform cobalt distribution. However, cobalt reducibility was hindered to some extent in the Co/SiO2 catalyst prepared by DBD plasma, while the zirconium additive prevented significantly the decrease in cobalt reducibility and increased cobalt dispersion as well as the FTS performance.
基金supported by the National Basic Research Program of China (No. 2013CB933100)the National Natural Science Foundation of China (21173174, 21161130522, 21033006 and 20923004)+1 种基金the Program for Changjiang Scholars and Innovative Research Team in University (No. IRT1036)the Research Fund for the Doctoral Program of Higher Education (No. 20090121110007)
文摘Carbon nanotube （CNT）-supported Ru nanoparticles with mean sizes ranging from 2.3 to 9.2 nm were prepared by different post-treatments and studied for Fischer-Tropsch （FT） synthesis. The effects of Ru particle size on catalytic behaviors were investigated at both shorter and longer contact times. At shorter contact time, where the secondary reactions were insignificant, the turnover frequency （TOF） for CO conversion was dependent on the mean size of Ru particles; TOF increased with the mean size of Ru particles from 2.3 to 6.3 nm and then decreased slightly. At the same time, the selectivities to C5＋ hydrocarbons increased gradually with the mean size of Ru particles up to 6.3 nm and then kept almost unchanged with a further increase in Ru particle size. At longer contact time, C10-C20 selectivity increased significantly at the expense of C21＋ selectivity, suggesting the occurrence of the selective hydrocracking of C21＋ to C10-C20 hydrocarbons.
基金supported by the National Natural Science Foundation of China(Grants No:20590360 and 20773166)
文摘Barium modified Co/Al2O3 catalysts were prepared by incipient wetness impregnation.The catalysts were characterized by XRD,TPD and DRIFTS.The catalytic activity for Fischer-Tropsch synthesis was measured in a continuously stirred tank reactor.It was found that small amounts of BaO（≤2 wt%） improved the cobalt reducibility,which led to more cobalt active sites on the catalyst surface,and then resulted in higher CO conversion and C5＋ selectivity.However,for the catalysts with high BaO loadings negative effects on the catalytic activity and selectivity for high hydrocarbons were observed because of low cobalt reducibility.
基金Foundation item:the National Natural Science Foundation of China(20590360)the Natural Science Foundation of Shanxi Province(2006021014)+1 种基金the National Outstanding Young Scientists Foundation of China(20625620)National Key Basic Research Program of China(973 Program)(2007CB216401).
文摘A systematic study was undertaken to investigate the effects of the manganese incorporation manner on the textural properties, bulk and surface phase compositions, reduction/carburization behaviors, and surface basicity of an iron-based Fischer-Tropsch synthesis （FTS） catalyst. The catalyst samples were characterized by N2 physisorption, X-ray photoelectron spectroscopy （XPS）, H2 （or CO） temperature-programmed reduction （TPR）, CO2 temperature-programmed desorption （TPD）, and M5ssbauer spectroscopy. The FTS performance of the catalysts was studied in a slurry-phase continuously stirred tank reactor （CSTR）. The characterization results indicated that the manganese promoter incorporated by using the coprecipitation method could improve the dispersion of iron oxide, and decrease the size of the iron oxide crystallite. The manganese incorporated with the impregnation method is enriched on the catalyst＇s surface. The manganese promoter added with the impregnation method suppresses the reduction and carburization of the catalyst in H2, CO, and syngas because of the excessive enrichment of manganese on the catalyst surface. The catalyst added manganese using the coprecipitation method has the highest CO conversion （51.9%） and the lowest selectivity for heavy hydrocarbons （C12＋）.
