Method and apparatus for regenerating an iron-based Fischer-Tropsch catalyst
AssigneeRentech, Inc.
InventorsBelma Demirel, Mark S. Bohn, Charles B. Benham, James E. Siebarth, Mark D. Ibsen
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Abstract
Solvent extraction is used to remove wax and contaminants from an iron-based Fischer-Tropsch catalyst in a natural circulation continuous-flow system. The wax-free catalyst is then subjected to controlled oxidation to convert the iron to its initial oxidized state, Fe2O3. Reactivation of the oxide catalyst precursor is carried out by addition of synthesis gas.
Claims51
A method for regenerating a deactivated iron-based Fischer-Tropsch catalyst from a slurry bubble column reactor, said method comprising the steps of:
- placing a slurry comprising wax and deactivated catalyst into a first vessel;
- feeding an inert gas into the bottom of the first vessel, thereby producing a three-phase bubble column in said first vessel wherein overhead gases are discharged to a separator;
- removing a degassed catalyst and wax bearing slurry from an upper portion of the first vessel and allowing the degassed catalyst and wax bearing slurry to flow under natural circulation through a catalyst settling vessel into a lower portion of the first vessel, whereby said deactivated catalyst having undergone settling is returned to said first vessel;
- adding an extraction solvent to said first vessel to maintain a desired level of catalyst bearing slurry as a catalyst-free wax and solvent mixture is removed from the catalyst settling vessel;
- separating wax and solvent in said catalyst-free wax and solvent mixture in a flash vessel, thereby generating a separated wax and a recovery solvent;
- recovering said separated wax;
- returning said recovery solvent to said first vessel;
- separating a dewaxed catalyst from the extraction solvent in said first vessel, thereby generating a wax-free catalyst-free solvent which undergoes vaporization and condensation for liquid storage;
- oxidizing said dewaxed catalyst in said first vessel under controlled conditions;
- mixing said dewaxed catalyst with a solvent containing an alkali promoter, thereby forming an oxide catalyst precursor;
- drying said oxide catalyst precursor to form a catalyst precursor powder;
- mixing said catalyst precursor powder with a liquid medium to form a catalyst precursor slurry;
- and
- treating the catalyst precursor slurry with a synthesis gas to form an active catalyst containing iron carbides, thereby regenerating said deactivated catalyst.
A method for regenerating a deactivated iron-based Fischer-Tropsch catalyst from a slurry bubble column reactor, said method comprising the steps of:
- placing a slurry comprising wax and deactivated catalyst into a first vessel;
- intimately mixing an extraction solvent with the slurry at a superficial velocity above about 2.5 cm/sec;
- extracting the wax from the slurry by passing a degassed catalyst bearing slurry through a catalyst settling vessel, whereby a catalyst-bearing slurry is returned to said first vessel, and by passing a catalyst-free wax and solvent mixture to a flash vessel for separating wax and solvent;
- separating a wax-free catalyst from an extraction solvent in said first vessel;
- oxidizing said wax-free catalyst in the first vessel under controlled conditions;
- mixing said wax-free catalyst with a solvent containing an alkali promoter, thereby forming an oxide catalyst precursor;
- drying said oxide catalyst precursor to form a catalyst precursor powder;
- mixing said catalyst precursor powder with a liquid medium to form a catalyst precursor slurry;
- and
- treating the catalyst precursor slurry with a synthesis gas to form an active catalyst containing iron carbides, thereby regenerating said deactivated catalyst.
Dependencies are inferred from the claim text.