Record number :
Title of article :
Coke deactivation of Pd/H-mordenite catalysts used for C5/C6 hydroisomerization Original Research Article
Author/Authors :
C.L. Li، نويسنده , , O. Novaro، نويسنده , , E. Mu?oz، نويسنده , , J.L. Bold?، نويسنده , , X. Bokhimi، نويسنده , , J.A. Wang، نويسنده , , T. L?pez، نويسنده , , R. G?mez، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2000
Pages :
From page :
To page :
Abstract :
Coke formation in C5/C6 alkane isomerization on a Pd/H-Mordenite catalyst discharged from a pilot reactor was studied. Experimental techniques like XRD, EPR, MAS-NMR, FTIR, TGA and TPO, were applied for the characterization of coke and coked catalysts. It was shown that coke content, chemical composition, its structure and nature depended upon time-on-stream and section of the catalyst bed. The coke content increased from 3.0 in the top section, to 4.1 wt.% in the central section and 6.2 wt.% in the bottom of the catalyst bed and C/H ratio of the corresponding coke increased from 1:1.12, 1:0.55 to 1:0.35, which significantly affected the catalytic behavior and regeneration of the catalysts. The selectivity to 2,2-dimethyl butane during n-hexane isomerization, respectively, decreased from 19% for the fresh catalysts, to 10% and 8.3% for the coked catalysts in the central and outlet sections. As time-on-stream increased, coke initially formed on palladium metals and then moved to acidic sites in the support where polyaromatic or pseudographite-like structures were formed through further acid catalyzed reactions. Two kinds of coke with different nature could be combusted below 300 and 600°C, respectively. These results are very useful for choosing operation parameters to restore initial activity of the coked catalysts in the regeneration units in our pilot plant.
Keywords :
Coke composition , Pd/H-mordenite , Hydroisomerization , Catalyst , Deactivation by coke , Pilot plant
Journal title :
Applied Catalysis A:General
Serial Year :
Link To Document :