Effects of deactivation and regeneration on the acidic function of commercial hydrocracking catalysts

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1984

OSTI ID:5393648

Absil, R P.L.

To determine the effects of deactivation and regeneration of the acidic function of a zeolite-containing hydrocracking catalyst, a series of fresh, commercially-deactivated, and regenerated catalysts were characterized using cumene transalkylation. Differential rate data obtained in a fixed-bed microreactor at a hydrogen or helium partial pressure of about 8.3 atm and temperatures ranging from 428 to 512/sup 0/K were extrapolated to zero time-on-stream to offset effects of catalyst deactivation during the experiments. These were classified into two categories such that the effects of unit cell size and wt% carbon on the cumene disproportionation activity could be assessed independently. As the unit cell size decreased, the adsorption equilibrium coefficient of the catalysts did not change, but the forward rate constant increased, went through a maximum, and decreased. The deactivation parameter on the other hand increased when the unit cell size decreased. At a constant unit cell size, the adsorption equilibrium coefficient of the regenerated catalysts did not change with wt% carbon, however, a linear relationship between the forward rate constant and wt% carbon was observed. This was attributed to the regeneration of the deactivated catalysts at highly diffusion-controlled conditions. At a constant unit cell size, the deactivated catalysts with high levels of coke (> 2 wt%) had similar activities. This was partially due to a reversible poison present on the surface of these deactivated catalysts. The decrease in the unit cell size during the deactivation and regeneration process was attributed to zeolite attack by water. In the regeneration process the water is formed as a byproduct of the coke oxidation reaction and, depending on the geometry of the bed, it can attack the zeolite framework.

• Research Organization: Northwestern Univ., Evanston, IL (USA)
• OSTI ID: 5393648
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020300* -- Petroleum-- Drilling & Production
ADSORPTION
ALKYLATION
AROMATICS
CATALYSTS
CATALYTIC CRACKING
CHEMICAL REACTIONS
COKE
CRACKING
CUMENE
DECOMPOSITION
HYDROCARBONS
HYDROCRACKING
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
MATERIALS
MINERALS
ORGANIC COMPOUNDS
OXIDATION
POISONING
PYROLYSIS
REGENERATION
SORPTION
THERMOCHEMICAL PROCESSES
ZEOLITES