Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J29/00—Catalysts comprising molecular sieves
  • B01J29/03—Catalysts comprising molecular sieves not having base-exchange properties
  • B01J29/0308—Mesoporous materials not having base exchange properties, e.g. Si-MCM-41
  • B01J29/0316—Mesoporous materials not having base exchange properties, e.g. Si-MCM-41 containing iron group metals, noble metals or copper
  • B01J29/0325—Noble metals
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
  • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
  • B01J23/40—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals of the platinum group metals
  • B01J23/42—Platinum
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
  • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
  • B01J23/40—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals of the platinum group metals
  • B01J23/44—Palladium
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J29/00—Catalysts comprising molecular sieves
  • B01J29/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
  • B01J29/041—Mesoporous materials having base exchange properties, e.g. Si/Al-MCM-41
  • B01J29/042—Mesoporous materials having base exchange properties, e.g. Si/Al-MCM-41 containing iron group metals, noble metals or copper
  • B01J29/043—Noble metals
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J29/00—Catalysts comprising molecular sieves
  • B01J29/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
  • B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
  • B01J29/064—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof containing iron group metals, noble metals or copper
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J31/00—Catalysts comprising hydrides, coordination complexes or organic compounds
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
  • B01J37/06—Washing
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
  • B01J37/12—Oxidising
  • B01J37/14—Oxidising with gases containing free oxygen
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
  • B01J37/16—Reducing
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
  • B01J37/16—Reducing
  • B01J37/18—Reducing with gases containing free hydrogen
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
  • B01J37/20—Sulfiding
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
  • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
  • B01J23/40—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals of the platinum group metals
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J35/00—Catalysts, in general, characterised by their form or physical properties
  • B01J35/30—Catalysts, in general, characterised by their form or physical properties characterised by their physical properties
  • B01J35/391—Physical properties of the active metal ingredient
  • B01J35/394—Metal dispersion value, e.g. percentage or fraction

Definitions

• the present invention relates to methods for the ex-situ activation and passivation of catalysts.
• these methods relate to supported noble metal catalysts on meso-porous or zeolitic materials. These techniques also apply to all catalyst that absorb water and use supported noble metals.
• Ex-situ reduction and dry passivation eliminate the need for extensive in-situ treatment. This reduces start-up time and eliminates the potential to damage noble metal dispersion during commercial in-situ reduction in the presence of moisture.
• the present invention is a process for the ex-situ reduction and dry passivation of a supported noble metal catalyst including a mesoporous or zeolitic matrix.
• the process includes the steps of reducing the catalyst and passivating the catalyst in the absence of excess liquid.
• the reduced catalyst is first cooled, in an inert atmosphere, and then exposed to air.
• the pores of the reduced catalyst may be filled with oil in an inert atmosphere. Since only the pores are filled with oil, the catalyst remains dry and free flowing.
• the supported metal catalyst is palladium and platinum supported on MCM-41 bound with alumina, which is described in U.S. 5,098,684.
• Figure 1 shows a comparison of the performance of a palladium and platinum supported catalyst that was reduced in-situ versus ex-situ according to the present invention as in Example 2.
• Figure 2 shows the catalyst performance of Example 4.
• Figure 3 shows the air passivated catalyst performance of Example 4.
• Figure 4 shows the oil pore-filled catalyst performance of Example 5.
• the present invention is a method of ex-situ activation and dry passivation of supported noble metal catalysts.
• the method comprises a two step procedure.
• Second, the reduced catalyst is dry passivated by cooling in an inert atmosphere and then exposing to air or by filling the pores of the catalyst with a ultra low sulfur mineral oil before exposing to air.
• the passivated catalysts are dry and free flowing and can be easily loaded into a commercial reactor, heated in hydrogen to remove free water & oxygen of passivation, and then started on oil feed, without any further treatment.
• Ex-situ reduction and passivation will reduce start-up time and eliminates the potential to damage noble metal dispersion during in-situ reduction in the presence of moisture. While ex-situ passivation of reduced catalysts in excess oil or wax has been practiced commercially, dry passivation with air or by oil-pore filling is novel and offers the advantage of a free flowing catalyst. Further, pilot plant data show that ex-situ reduced and dry passivated catalysts have equivalent performance as catalysts having been subjected to a controlled in-situ drying and reductions step using completely dry gases. The method described in the examples below is for palladium and platinum supported on MCM-41 bound with alumina.
• the catalyst comprises 0.3 wt% platinum and 0.9 wt% palladium supported on MCM-41 bound with alumina. Platinum and palladium are highly dispersed on the surface of the catalyst support by first absorbing onto the support an aqueous solution of platinum and palladium tetrammine nitrate. After metals coating, the support is dried and then calcined in air to decompose the tetrammines, leaving behind finely dispersed platinum and palladium oxides. Prior to use, the catalyst must be activated by reducing the platinum and palladium oxides without damaging metal dispersion.
• the noble metals can be reduced ex- situ and the reduced catalysts immediately immersed into excess oil, wax, or other liquid (in an inert atmosphere) to passivate the noble metals.
• catalysts immersed in excess liquid are very difficult to handle and are only useful for single bed reactors because they are impossible to load into most multi-bed reactors.
• the supported noble metal oxides are first dried and reduced in a single step in the presence of a mixture of hydrogen and inert gas in a rotary calciner.
• oxygen chemisorption results on the nitrogen blanketed samples following ex-situ reduction in a rotary calciner show that the catalyst was fully reduced with no agglomeration of noble metals.
• the air-passivated catalyst was prepared by cooling the reduced catalyst in nitrogen and then slowly exposing the reduced catalyst to air at room temperature. In this step, oxygen is absorbed onto the catalyst surface preventing oxidation of the reduced noble metals. Oxygen chemisorption measurement (0.01 O/M) shown in Table 2 indicates that the noble metal sites are covered with oxygen. Further, chemisorption experiments also indicate that the oxide coating can be easily removed at very mild conditions (>35°C in hydrogen) to expose fully reduced and highly dispersed, active noble metal sites.
• the oil pore-filled passivated catalyst was prepared, under inert gas (N2), using a oil pore-filled passivation technique.
• medicinal grade white oil was added to the reduced catalyst to fill about 95% of the pores volume.
• Reduced catalyst samples passivated with oil could not be analyzed by oxygen chemisorption.
• Example 2 The reduced and passivated catalyst samples from Example 2 were loaded into a pilot plant reactor and the performance of each catalyst was evaluated for hydroflnishing a hydrotreated 600N dewaxed oil.
• the dewaxed oil was previously hydrotreated to reduce the sulfur content to about 200 wppm.
• Approximately 5 cc of three, ex-situ reduced and passivated noble metal catalysts were loaded into an upflow micro-reactor. These included noble metal catalysts that were all ex-situ reduced and passivated by (1) immersion in excess oil, as currently practiced, (2) exposure to ambient air or (3) pore filing with mineral oil.
• the catalysts were heated to 15O 0 C in hydrogen with 2 psi water partial pressure, simulating a typical commercial start-up with recycled hydrogen and treat gas scrubbing. Oil feed was then started and operating conditions were adjusted to 2 LHSV, 1000 psig, and 2,500 scf/bbl. Reactor temperature was increased to 275 0 C and then held constant for about 7-10 days. Hydrogen purity was 100% and no gas recycle was used.
• Hydrotreated dewaxed oil was used as the process feedstcock for catalyst evaluation.
• This oil is a dewaxed oil (-18 0 C) containing traces level of sulfur (4.7 wppm) and approximately 5.5 wt% aromatics (124 mmol/kg).
• the wet-gases treatment on the oxide catalyst was a base case against which air and oil passivated catalyst performance was compared.
• the noble metal catalyst in its oxide state was subjected to a drying step (140 0 C) and a reduction step (22O 0 C) with wet gases containing about 2.2 psia water partial pressure. Previous studies have shown that under these reduction conditions metal sintering will occur resulting in a lower performing catalyst.
• the catalyst was subjected to an increase in water partial pressure to 3.5 psia for about 1 hour, at 150 0 C, prior to switching to dry hydrogen.
• the unit pressure was then slowly increased to 2000 psig operating pressure, and the dewaxed oil was introduced.
• reactor temperature was increased to the operating temperature of 22O 0 C.
• catalyst performance was again compared to the performance of the oxide catalyst that was dried and reduced using the conventional pilot plant start-up with dry-gases. This catalyst was dried in N 2 at 150 0 C and reduced in H 2 at 25O 0 C for 8 hours.
• treatment of the oxide catalyst with wet gases resulted in a lower performing catalyst than that for the dry treatment.
• the oxide wet and dry gases treated catalyst performances are summarized in Table 3 and Figure 2.
• the air and oil pore-filled reduced and passivated catalysts were all subjected to wet-gas treatment. Two reactors were loaded with the air- passivated catalyst. One catalyst was subjected to a 2 hours drying step (140 0 C) and a 16 hours reduction step (14O 0 C) with wet gases containing about 1-psia water partial pressure. The second air-passivated catalyst was directly reduced with wet hydrogen at 140 0 C for 16 hours, eliminating the drying step.
• Figure 3 and Table 4 indicate lower performance of the air
• Figure 3 and Table 4 indicate lower performance of the air passivated catalysts when treated with wet nitrogen and hydrogen. It is clear that the catalyst activity is significantly lower to that of the catalyst dried and reduced with dry gases.
• Figure 4 and Table 4 show that oil pore-filled passivated catalyst performance is similar to that of the oxide catalyst of Example 4 dried and reduced following the conventional pilot plant procedure, using dry gases. These results would indicate that no significant metal sintering occurred and that the active metal was fully accessible for the hydrogenation reaction.

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• 2005
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