Rejuvenation of hydrocarbon synthesis catalyst

Abstract

A cobalt- or ruthenium-containing hydrocarbon synthesis catalyst, subjected to short term, reversible, partial deactivation in a slurry synthesis process can be rejuvenated, i.e., at least about 80+% catalyst activity recovery, by treating the catalyst in the presence of liquid hydrocarbons, preferably the slurry hydrocarbons, with hydrogen at elevated temperatures and pressures.

What is claimed is:  
     
       1. A method for rejuvenating a partially deactivated, Group VIII metal containing Fischer-Tropsch catalyst having an initial catalyst activity which comprises: suspending the catalyst in slurry liquid hydrocarbons and treating the suspended catalyst with hydrogen or a hydrogen containing gas at elevated temperatures and pressures and recovering a substantial portion of the initial catalyst activity. 
     
     
       2. The method of  claim 1  wherein the catalyst contains iron, cobalt, or ruthenium. 
     
     
       3. The method of  claim 2  wherein rejuvenation is effected at temperatures ranging from 135° C. to 425° C. 
     
     
       4. The method of  claim 1  wherein at least a portion of the energy required for maintaining the catalyst in a suspension is supplied by injection of hydrogen containing gas. 
     
     
       5. The method of  claim 1  wherein deactivation resulted from a slurry phase hydrocarbon synthesis process. 
     
     
       6. The method of  claim 1  wherein the pressure is about hydrocarbon synthesis pressure and the temperature ranges from hydrocarbon synthesis temperature to about 40° C. below hydrocarbon synthesis temperature. 
     
     
       7. The method of  claim 6  wherein at least about 90% of initial catalyst productivity is recovered. 
     
     
       8. The method of  claim 6  wherein the catalyst contains catalytically active amounts of cobalt. 
     
     
       9. The method of  claim 8  wherein the catalyst is cobalt supported on a Group IVB oxide. 
     
     
       10. The method of  claim 9  wherein the catalyst is a supported cobalt catalyst. 
     
     
       11. A method for producing liquid C 5    plus hydrocarbons in a slurry phase reactor with catalyst comprising rejuvenating said catalyst in situ according to the method of    claim 1   .   
     
     
       12. The method of  claim 11  wherein said C 5+    hydrocarbons comprise C   5   -C   50    hydrocarbons.   
     
     
       13. The method of  claim 11  wherein said C 5+    hydrocarbons comprise Fischer - Tropsch waxes.