Method and apparatus for regenerating an iron-based fischer-tropsch catalyst
View Patent ↗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, Fe 2 O 3 . Reactivation of the oxide catalyst precursor is carried out by addition of synthesis gas.
1. An apparatus for removing wax and impurities from a deactivated iron-based Fischer-Tropsch catalyst, said apparatus comprising:
extraction means functioning to extract wax from said deactivated catalyst in a catalyst bearing slurry using an extraction solvent in the presence of an inert gas;
said extraction means having a heating means functioning to heat inlet gases;
a first cooling means functioning to cool overhead gases from said extraction means;
a second cooling means functioning to condense solvent present in said cooled overhead gases;
a first separator means functioning to separate said cooled overhead gases from said condensed solvent exiting said second cooling means;
catalyst settler means functioning to produce a catalyst-free, wax-laden solvent mixture from said catalyst bearing slurry;
heating means functioning to increase temperature of the wax-laden solvent mixture before said wax-laden solvent mixture undergoes flash evaporation;
flash evaporator means functioning to separate solvent vapor from liquid wax in said wax-laden solvent mixture;
a third cooling means functioning to condense said solvent vapor discharged from said flash evaporator means;
a second separator means functioning to separate said condensed solvent from gases exiting said flash evaporator means;
solvent storage means functioning to store condensed solvent from said first and second separator means; and
wax storage means functioning to store liquid wax from said flash evaporator means.
2. The apparatus of claim 1 , wherein said extraction means is a three-phase bubble column.
3. The apparatus of claim 1 further comprising pressure control means functioning to control pressure said extraction means.
4. The apparatus of claim 1 further comprising flaring means functioning to dispose of tail gases from said first and second separator means.
5. The apparatus of claim 1 further comprising solvent pump means functioning to pump condensed solvent to said extraction means.
6. The apparatus of claim 1 further comprising wax pump means functioning to pump liquid wax from said wax storage means to a wax recovery system.
7. The apparatus of claim 1 , wherein said extraction means further comprises gas distribution means functioning to distribute gas bubbles in said inert gas uniformly across a cross sectional area of said extraction means.
8. The apparatus of claim 7 , wherein said gas distribution means is a sintered metal plate.
9. The apparatus of claim 8 , wherein said sintered metal plate has an average pore diameter between about 0.2 and about 2 microns.
10. The apparatus of claim 1 , wherein said extraction means further comprises a temperature control means functioning to maintain the catalyst bearing slurry at a desired temperature.
11. The apparatus of claim 1 , wherein said catalyst settler means further comprises an external heating means functioning to maintain the catalyst bearing slurry at a desired temperature.
12. The apparatus of claim 1 , wherein the catalyst settling means further comprises a dynamic settler.