Catalyst – solid sorbent – or support therefor: product or process – Regenerating or rehabilitating catalyst or sorbent – Gas or vapor treating
Reexamination Certificate
2000-05-12
2002-05-07
Griffin, Steven P. (Department: 1754)
Catalyst, solid sorbent, or support therefor: product or process
Regenerating or rehabilitating catalyst or sorbent
Gas or vapor treating
C502S056000, C502S049000
Reexamination Certificate
active
06383965
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a process for regenerating a spent molecular sieve catalysts of the Fluidized Catalytic Cracking Unit (FCCU) in oil refinery. More particularly, the present invention relates to a process for regenerating a spent molecular sieve catalysts using two riser regenerators.
DESCRIPTION OF THE PRIOR ART
Up till now, the molecular sieve catalyst, which has been used in FCCU, is regenerated in a fluidized bed and a combustion riser. The combustion riser is not used alone, and must be used in combination with a fluidized bed. But, the fluidized bed regeneration has the following problems: long catalyst residence time, serious catalyst back-mixing, low Carbon Burning Intensity (CBI), complicated inside structures, difficult to uniformly fluidize and keep a good distribution of particles, easy damage of the inside equipment, etc.
In recent years, the riser regenerator has received substantial interest. But, coke combustion in the riser regenerator requires circulation of a high temperature catalyst and air injection at various heights of the riser regenerator, and back-mixed problem has not been solved. It is not able that main operation parameters such as space-velocity and temperature are both high at the same time.
BRIEF SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a process of regenerating spent molecular sieve catalysts comprising the steps of:
(1) mixing a high temperature flue gas that comes from a second group of cyclones with the spent catalyst in a first riser regenerator to form a mixture of a half-regenerated catalyst and a flue gas at the top of the first riser regenerator;
(2) separating the half-regenerated catalyst from the mixture in a first group of cyclones;
(3) mixing the half-regenerated catalyst that comes from the first group of cyclones with a sufficient amount of air for burning off all coke on the spent catalyst in a second riser regenerator to form a mixture of a high temperature flue gas and a regenerated catalyst at the top of the second riser regenerator;
(4) separating the regenerated catalyst from the mixture in the second group of cyclones; and
(5) recovering surplus heat from the regenerated catalyst that comes from the second group of cyclones by a regenerated catalyst cooler which is located outside of the second riser regenerator.
REFERENCES:
patent: 3412013 (1968-11-01), Bowles
patent: 4010094 (1977-03-01), McKinney
patent: 4198287 (1980-04-01), Hemler, Jr. et al.
patent: 4284583 (1981-08-01), Pujado
patent: 0790075 (1997-08-01), None
patent: 9637299 (1996-11-01), None
Griffin Steven P.
Johnson Edward M.
Ladas & Parry
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