Cyclic propylene steaming

FCC catalyst, supplied by Grace Davison, at three different cat-to-oil ratios, 4,6, and 8. The feed was injected at a constant rate of 3 g/min for 30 seconds. The catalyst to oil ratio was adjusted by varying the amonnt of catalyst in the reactor. Two catalysts used for this evaluation were laboratory deactivated using the cyclic propylene steaming (CPS) method [6]. Properties of these catalysts after deactivation are listed in Table 12.3. 

Rajagopalan et al [30] confirm that methods involving cyclic redox aging of metals in the presence of sulphur are needed for screening metals tolerant catalyst. A simplified cyclic test (cyclic propylene steam) method is proposed which addresses the redox ageing of the metal, but not the non-uniform laydown and age distribution of metals on the catalyst. 

Properties Mitchell Method Cyclic Metals Impregnation Cyclic Propylene Steam... 

Contaminant-Metal Deactivation and Metal-Dehydrogenation Effects During Cyclic Propylene Steaming of Fluid Catalytic Cracking Catalysts... 

Recent work on laboratory catalyst deactivation in the presence of Ni and V by cyclic propylene steaming (CPS) has shown that a number of conditions affect the dehydrogenation activity and zeolite destruction activity of the individual metals. These conditions include find metal oxidation state, overall exposure of the metal to oxidation, the catalyst composition, the total metal concentration and the NiA ratio. Microactivity data, which show dramatic changes in coke and hydrogen production, and surface area results, which show changes in zeolite stability, are presented that illustrate the effect each of these conditions has on the laboratory deactivation of metals. The CPS conditions which are adjustable, namely final metal oxidation state and overall exposure of the metal to oxidation are used as variables which can control the metal deactivation procedure and improve the simulation of commercial catalyst deactivation. In particular, the CPS procedure can be modified to simulate both full combustion and partial combustion regeneration. 

BOOCK ET AL. Cyclic Propylene Steaming ofFCC Catalysts... 

After cyclic propylene steam 30 cycles with 60% volume H2O cycled between balance gas of 5% wt. C3H6 in N2, and air with 4000 ppm SO2, total time 20 hrs.,T = 77rC, Fluid Bed... 

A trap was then blended with 90wt% fresh catalyst and steamed by cyclic propylene steam (CPS) for 20 hours. After steaming, the catalyst and trap were density separated and analyzed for vanadium. Results are presented in Table 8. As shown in the table, less than 6% of the vanadium migrates back to the catalyst. This represents an insignificant amount of the total vanadium transferred. Additionally, since the vanadium on the catalyst may migrate back to the trap over time, the degree of reversibility may actually decrease with time. 

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