Accelerated deactivation of ruthenium-promoted alumina-supported alkalized cobalt （K-Ru-Co/γ-Al 2 O 3 ） Fischer-Tropsch （FT） synthesis catalyst along the catalytic bed over 120 h of time-on-stream （TOS） was inv...Accelerated deactivation of ruthenium-promoted alumina-supported alkalized cobalt （K-Ru-Co/γ-Al 2 O 3 ） Fischer-Tropsch （FT） synthesis catalyst along the catalytic bed over 120 h of time-on-stream （TOS） was investigated. Catalytic bed was divided into three parts and structural changes of the spent catalysts collected from each catalytic bed after FT synthesis were studied using different techniques. Rapid deactivation was observed during the reaction due to high reaction temperature and low feed flow rates. The physico-chemical properties of the catalyst charged in the Bed #1 of the reactor did not change significantly. Interaction of cobalt with alumina and the formation of CoAl 2 O 4 increased along the catalytic bed. Reducibility percentage decreased by 4.5%, 7.5% and 12.9% for the catalysts in the Beds #1, #2 and #3, respectively. Dispersion decreased by 8.8%, 14.4% and 26.6% for the catalysts in the Beds #1, #2 and #3, respectively. Particle diameter increased by 0.6%, 2.4% and 10.4% for the catalysts in the Beds #1, #2 and #3, respectively, suggesting higher rate of sintering at the last catalytic bed. The amount of coke at the last catalytic bed was significantly higher than those of Beds #1 and #2.展开更多
Destructive tests of the catalyst was carried out to study the effect oftemperature on the catalytic activity of CO coupling to diethyl oxalate (DEO) over a Pd-Fe/Al_2O_3catalyst. It was found that a temperature jump ...Destructive tests of the catalyst was carried out to study the effect oftemperature on the catalytic activity of CO coupling to diethyl oxalate (DEO) over a Pd-Fe/Al_2O_3catalyst. It was found that a temperature jump could cause the deactivation of the Pd-Fe/α-Al_2O_3catalyst. The catalyst deactivated at different temperatures has different characteristics. Afterdeactivation the crystal structure of α-Al_2O_3 did not change, but the Pd particle size wasenlarged. Most of the Pd^0 were oxidized to Pd^(2+), and Fe^(2+) was oxidized to Fe^(3+) on thesurface of the deactivated catalyst. The catalyst could be regenerated, but its original activitycould not be recovered completely.展开更多
文摘Accelerated deactivation of ruthenium-promoted alumina-supported alkalized cobalt （K-Ru-Co/γ-Al 2 O 3 ） Fischer-Tropsch （FT） synthesis catalyst along the catalytic bed over 120 h of time-on-stream （TOS） was investigated. Catalytic bed was divided into three parts and structural changes of the spent catalysts collected from each catalytic bed after FT synthesis were studied using different techniques. Rapid deactivation was observed during the reaction due to high reaction temperature and low feed flow rates. The physico-chemical properties of the catalyst charged in the Bed #1 of the reactor did not change significantly. Interaction of cobalt with alumina and the formation of CoAl 2 O 4 increased along the catalytic bed. Reducibility percentage decreased by 4.5%, 7.5% and 12.9% for the catalysts in the Beds #1, #2 and #3, respectively. Dispersion decreased by 8.8%, 14.4% and 26.6% for the catalysts in the Beds #1, #2 and #3, respectively. Particle diameter increased by 0.6%, 2.4% and 10.4% for the catalysts in the Beds #1, #2 and #3, respectively, suggesting higher rate of sintering at the last catalytic bed. The amount of coke at the last catalytic bed was significantly higher than those of Beds #1 and #2.
基金Supported by National"Ninth-Five" Scientific Research Project(Grant number:96-539-01)
文摘Destructive tests of the catalyst was carried out to study the effect oftemperature on the catalytic activity of CO coupling to diethyl oxalate (DEO) over a Pd-Fe/Al_2O_3catalyst. It was found that a temperature jump could cause the deactivation of the Pd-Fe/α-Al_2O_3catalyst. The catalyst deactivated at different temperatures has different characteristics. Afterdeactivation the crystal structure of α-Al_2O_3 did not change, but the Pd particle size wasenlarged. Most of the Pd^0 were oxidized to Pd^(2+), and Fe^(2+) was oxidized to Fe^(3+) on thesurface of the deactivated catalyst. The catalyst could be regenerated, but its original activitycould not be recovered completely.
