Fresh-catalyst properties

With each shipment of fresh catalyst, the catalyst suppliers typically mail refiners an inspection report that contains data on the catalyst s physical and chemical properties. This data is valuable and should be monitored closely to ensure that the catalyst received meets the agreed specifications. A number of refiners independently analyze random samples of the fresh catalyst to confirm the reported properties. In addition, quarterly review of the fresh catalyst properties with the catalyst vendor will ensure that the control targets are being achieved. 

Verify that the fresh catalyst properties have not changed... 

The fresh catalyst properties that increase gasoline yield are ... 

Catalyst Steamed Catalyst Properties Surface Area, irfVgram X-Ray Crystallinity, wt % Total Rare Earth, wt % Unit Cell Size, A FAI Activity, % Fresh Catalyst Properties Unit Cell Size, A Surface Area, rr /gram A 75 8 3 24.36 66 24.51 221 B 162 28 0.2 24.28 66 24.43 202... 

FRESH CATALYST PROPERTIES ENGELHARD DYNAMICS CATALYSTS... 

Changing catalyst properties. This can be due to changes in the fresh catalyst s physical properties and/or malfunctioning of the cyclones. 

Changes in the fresh catalyst s physical properties may contribute to catalyst losses. The losses could be due to the fresh catalyst s being soft. Softness is evidenced by the quality of the catalyst binder and the large amount of 0-40 microns. It will increase the attrition tendency of the catalyst and thus its losses. 

The fresh catalyst s chemical properties also influence the FCC gasoline octane. Gasoline octane is increased by ... 

Of the various mechanical properties of a formed catalyst containing zeolite, attrition resistance is probably the most critical. This is particularly the case for FCC catalysts because of the impact on the addihon rate of fresh catalyst, particulate emissions of fines and overall catalyst flow in the reactor and regenerator. Most attrition methods are a relative determination by means of air jet attrition with samples in the 10 to 180 xm size range. For example the ASTM D5757 method attrites a humidified sample of powder with three high velocity jets of humidified air. The fines are continuously removed from the attrition zone by elucidation into a fines collection assembly. The relative attrition index is calculated from the elutriated fines removed at a specific time interval. 

Optimizing the fresh catalyst physical properties including particle density, PSD, and attrition resistance is critical to maintaining acceptable fluidization and resulting circulation of the catalyst inventory. Excessive attrition of the catalyst will lead to nonuniform fluidization and disrupt circulation. Potential sources of attrition include ... 

Utilize a denser, coarser grade PSD fresh catalyst while ensuring that the fluidization properties remain acceptable... 

Based on the results of Dalla Betta and co-workers, it is clear that the steady-state activity of a completely sulfur-poisoned Ni or Ru methanation catalyst is 102-104 times lower than that of the fresh catalyst. However, a typical industrial methanation process would more probably involve a catalyst only partly poisoned by sulfur. Bartholomew and co-workers (23, 113, 157) attempted to assess how sulfur poisoning of only a portion of the catalyst would affect its activity/selectivity properties in fixed-bed and fluidized-bed reactors. Data in Table XII show the effects on specific activity and product distribution of partially presulfided Co/A1203 and Ni/Al203 catalysts in a fixed bed. Catalysts were presulfided with 10 ppm H2S at 725 K, and reaction was carried out with sulfur-free feedgas. Corresponding data are listed in Table XIII for catalysts partially presulfided and then studied in a fluidized-bed reactor under the same conditions. The decrease in H2 uptake... 

The hydrogenation process is carried out at 500°C and pressures in excess of 30 atm in fixed bed reactors containing catalysts with varying physical properties to accommodate the metal deposition that occurs during the reaction. In some cases moving bed reactors are used where spent catalyst is continuously removed and fresh catalyst added. 

The results from this study show that the choice of steaming/MAT procedures selected for evaluation of fresh FOC catalyst can effect the observed ranking of catalyst performance. The most method dependent selectivity was found to be the coke yield. In making assessments of the catalytic performance of FOC catalysts it is important that consideration of the steamed catalyst properties as they relate to commercial experience be given high priority. 

Effect of Na on Fresh and Steam Deactivated Catalysts Properties of the two USY silica sol catalyst samples, having different method of sodium incorporation, are shown in Table 3. Both samples had similar zeolite and matrix surface areas and zeolite unit cell size after 4 hours at 1088K steaming. 

Table 3. Catalyst Properties Effect of Na on Fresh Catalyst vs. Na Impregnation After Hydrothermal Aging...

XFS and HDS activity data obtained for both fresh and spent catalysts are sutnmariied in Table As explained in the experi-mental section, the signal intensity ratios and the catalyst properties (surface area and loadings) are used to calculate the thickness (t) and the coverage C ) of layers. For the coke-containing catalysts an assumption on the relative distribution of coke and active components has eo be made. It is enpha-sized that in all Calculations we have that the coke Is randomly dis-... 

The residual activities for the commercially used catalysts are tabulated in Table 2 together with some physical property data enabling comparison with those for fresh catalysts to weigh the effects of other factors besides sulfur poisoning on activity. 

From the values of TOF, the increasing order of activity for the fresh catalysts in the hydrogenation of ethylbenzene is Pd < Ni < Pt < Rh < Ru, Concerning the deactivation process, the intrinsic order of sulfur resistance appears to be Ru Rh Ni > Pd > Pt. On the other hand, the half deactivation time and the catalyst life decrease in the order Rh > Ru Pd Ni > Pt. This difference is due to the fact that the lifetime of a particular catalyst is an extensive property, which depends both on the deactivation rate constant (k l and the initial number of exposed metal atoms (N). Finally, we want to point out the small differences in the activity found for the fresh catalysts (CRu/CPd - 1.6), as compared with the greater values of their sulfur resistance (CRu/CPd = 6.5 or CRu/CPt = 12.5). 

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