Deactivation profile

The transformation of cyclopentanol-cyclohexanone mixture was carried out in a fixed-bed reactor at 200°C and 250°C under atmospheric pressure and in the presence of nitrogen (nitrogen/reactant molar ratio = 4). The reactant was an equimolar mixture of cyclopentanol and cyclohexanone. The reaction products were analyzed on line by GC (VARIAN 3400 chromatograph, equipped with a SGE CIDEX B 25 m x 0.22 mm column and a flame ionization detector). The deactivation profile was obtained by analyzing reaction effluent for various times-on-stream (TOS). 

Monitoring Fluid Cracking Catalyst Deactivation Profile by Equilibrium Catalyst Separation... 

The comparison of physical properties of laboratory-steamed catalyst with those of equilibrium catalyst fractions given in Table VII indicates that a wide range of steaming temperatures is necessary to reproduce the equilibrium catalyst deactivation profile for lab steaming times of one day or less. These results indicate that an improved catalyst aging procedure for simulating... 

DEACTIVATION PROFILES RELATED TO MECHANISM REGULARITIES OF COKE FORMATION INSIDE CATALYST PORES... 

Figure 2. Deactivation profiles for experiments of type 1 and 2. Rate constants for HD formation in mol/(s, g cat., Pa) 10. The first GC-analyses were done 1.5 minutes after a stop and are marked with gray squares and rombs. In the end of the type 1 runs, three stops without exposure to hydrogen were performed (marked with black squares and rombs).

A large effect on the deactivation profile, due to the H2-D2 experiments was found. During the first hours of a run, the deactivation was accelerated after each stop for an H2-D2 experiment. A step down in activity directly after a stop, and then a slight increase in activity, was found. This increased deactivation is probably due to dehydrogenation of species on the surface in the absence of hydrogen. After more than 15 h on stream the conversion of propane increased immediately after each H2-D2 experiment followed by a slow return to the initial deactivation profile. This activity increase was much higher for the Pt-Sn catalyst compared to the Pt catalyst... 

The H2-D2 equilibration reaction was shown to be useful as a probe for measuring the metal area not covered by coke, on Pt/Al203 and Pt-Sn/AL03 catalysts deactivated during propane dehydrogenation. Problems with the method are the effect that the repeated stops have on the dehydrogenation deactivation profile, and the difficulties in correlating the HD formation rate to free metal area. 

Like all catalysts the F-T catalysts deactivate with time on line. The deactivation process is typical of most catalysts in that studies reveal a rapid initial loss in activity followed by activity stabilization with a subsequent gradual decrease in activity (6). The latter decline in activity has important ramifications for the actual lifetime of the catalyst. It is therefore important to identify and minimize the factors that influence this part of the deactivation profile in order to maximize the catalyst lifetime. 

Monitoring FCC Deactivation Profile by Equilibrium Catalyst Separation", ACS... 

If (12) the composition of the gas phase is accounted for in the site coverage, so that a deactivation profile for the main reaction can be predicted, but there is still no equation for the coke content This Information is important for the guidance of the regeneration of the catalyst Also, in kinetic studies of deactivation based upon (12), the function... 

Figure S. Deactivation profiles for Pt and Pt-Re catalysts. Ref [7], Reproduced by permission of Academic Press, Inc.

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