Method of converting fischer-tropsch products into aromatics-containing jet fuel

Abstract

Processes for converting Fischer-Tropsch products into aromatics are described. The processes involve processing the Fischer-Tropsch effluent or hydrocracked Fischer-Tropsch effluent (or a selected portion thereof) in a separate, low pressure reforming reaction zone. The reforming catalyst promotes cyclization and aromatics production. The processes can include an isomerization process to convert normal paraffins to isoparaffins.

What is claimed is: 
     
         1 . A method of converting a Fischer-Tropsch product into aromatic compounds comprising:
 providing a Fischer-Tropsch product stream comprising C 20+  normal paraffins;   hydrocracking the Fischer-Tropsch product stream in a hydrocracking reaction zone comprising a hydrocracking reactor in the presence of a hydrocracking catalyst under hydrocracking conditions to form a hydrocracked Fischer-Tropsch product stream comprising C 1  to C 20  isoparaffins and normal paraffins; and   reforming the hydrocracked Fischer-Tropsch product stream in a reforming reaction zone comprising a reforming reactor in the presence of a reforming catalyst under reforming conditions to form an aromatic product stream comprising C 6  to C 16  aromatic compounds.   
     
     
         2 . The method of  claim 1  wherein reforming the hydrocracked Fischer-Tropsch product stream comprises reforming at least a portion of the hydrocracked Fischer-Tropsch product stream. 
     
     
         3 . The method of  claim 2  wherein the portion of the hydrocracked Fischer-Tropsch product stream comprises C 6  to C 16  paraffins. 
     
     
         4 . The method of  claim 2  wherein the portion of the hydrocracked Fischer-Tropsch product stream comprises C 7  to C 12  paraffins. 
     
     
         5 . The method of  claim 1  wherein providing the Fischer-Tropsch product stream comprises:
 reacting synthesis gas comprising hydrogen and carbon monoxide or carbon dioxide or both in a Fischer-Tropsch reaction zone comprising a Fischer-Tropsch reactor in the presence of a Fischer-Tropsch catalyst under Fischer-Tropsch reaction conditions to form the Fischer-Tropsch product stream; and wherein: 
 the Fischer-Tropsch reaction conditions comprise a temperature in a range of 150° C. to 300° C., or a pressure in a range of 200 to 750 psig, or both; or 
 the Fischer-Tropsch catalyst comprises a Fe-, Co-, Ni-, Ru-based catalyst or combinations thereof; 
 or both. 
 
     
     
         6 . The method of  claim 1  further comprising:
 separating the hydrocracked Fischer-Tropsch product stream into at least a C 6  to C 16  paraffin stream comprising C 6  to C 16  paraffins before reforming the hydrocracked Fischer-Tropsch product stream; and 
 wherein reforming the hydrocracked Fischer-Tropsch product stream comprises reforming the C 6  to C 16  paraffin stream. 
 
     
     
         7 . The method of  claim 1  further comprising:
 separating the hydrocracked Fischer-Tropsch product stream into at least a C 7  to C 12  paraffin stream comprising C 7  to C 12  paraffins; and 
 wherein reforming the hydrocracked Fischer-Tropsch product stream comprises reforming the C 7  to C 12  paraffin stream. 
 
     
     
         8 . The method of  claim 1  wherein:
 the hydrocracking reaction conditions comprise a temperature in a range of 290° C. to 470° C., or a pressure in a range of 300 to 1500 psig, or both; or 
 the hydrocracking catalyst comprises Y zeolite, beta zeolite, SiO 2 —Al 2 O 3 , noble metals, base metals, or combinations thereof; 
 or both. 
 
     
     
         9 . The method of  claim 1  wherein:
 the reforming reaction conditions comprise a temperature in a range of 400° C. to 600° C., or a pressure in a range of 60 psig to less than 400 psig, or both; or 
 the reforming catalyst comprises a zeolite-based catalyst with greater than 0 up to 1 wt % of a noble metal, or a chlorinated alumina based catalyst with greater than 0 up to 1 wt % of a noble metal, Sn, Ge, Ga, In, Re, or combinations thereof; 
 or both. 
 
     
     
         10 . A method of converting a Fischer-Tropsch product into aromatic compounds comprising:
 providing a Fischer-Tropsch product stream comprising C 5+  normal paraffins,   hydrocracking a first portion of the Fischer-Tropsch product stream comprising C 16+  normal paraffins in a hydrocracking reaction zone comprising a hydrocracking reactor in the presence of a hydrocracking catalyst under hydrocracking conditions to form a hydrocracked Fischer-Tropsch product stream comprising C 1  to C 20  isoparaffins and normal paraffins; and   reforming a second portion of the Fischer-Tropsch product stream comprising C 5  to C 16  normal paraffins in a reforming reaction zone comprising a reforming reactor in the presence of a reforming catalyst under reforming conditions to form an aromatic product stream comprising C 6  to C 16  aromatic compounds.   
     
     
         11 . The method of  claim 10  further comprising:
 isomerizing the hydrocracked Fischer-Tropsch product stream in an isomerization reaction zone comprising an isomerization reactor in the presence of an isomerization catalyst under isomerization conditions to form an isomerized product stream comprising C 4  to C 20  normal paraffins and isoparaffins. 
 
     
     
         12 . The method of  claim 11  further comprising:
 separating the isomerized product stream into an SPK stream comprising synthetic paraffinic kerosene comprising C 9 -C 16  paraffins, a naphtha stream comprising C 5  to C 8  paraffins, and an unconverted oil stream comprising C 21+  paraffins. 
 
     
     
         13 . The method of  claim 12  further comprising:
 recycling the unconverted oil stream to the hydrocracking reaction zone. 
 
     
     
         14 . The method of  claim 12  wherein at least a portion of the naphtha stream is reformed in the reforming reaction zone. 
     
     
         15 . The method of  claim 11  wherein:
 the isomerization reaction conditions comprise a temperature in a range of 315° C. to 430° C., or a hydrogen partial pressure in a range of 300 psig to 1000 psig, or both; or 
 the isomerization catalyst comprises a one-dimensional 10 member-ring molecular-sieve catalyst with a noble metal. 
 
     
     
         16 . The method of  claim 11  wherein a wt % of C to C 20  isoparaffins in the isomerized product stream is greater than a wt % of C 7  to C 20  normal paraffins in the isomerized product. 
     
     
         17 . The method of  claim 10  wherein the second portion comprises C 6  to C 12  normal paraffins. 
     
     
         18 . The method of  claim 10  wherein providing the Fischer-Tropsch product stream comprises:
 reacting synthesis gas comprising hydrogen and carbon monoxide in a Fischer-Tropsch reaction zone comprising a Fischer-Tropsch reactor in the presence of a Fischer-Tropsch catalyst under Fischer-Tropsch reaction conditions to form the Fischer-Tropsch product stream; and wherein: 
 the Fischer-Tropsch reaction conditions comprise a temperature in a range of 150° C. to 300° C., or a pressure in a range of 200 to 750 psig, or both; or 
 the Fischer-Tropsch catalyst comprises a Fe-, Co-, Ni-, Ru-based catalyst or combinations thereof; 
 or both. 
 
     
     
         19 . The method of  claim 10  wherein:
 the hydrocracking reaction conditions comprise a temperature in a range of 290° C. to 470° C., or a pressure in a range of 300 to 1500 psig, or both; or 
 the hydrocracking catalyst comprises Y zeolite, beta zeolite, SiO 2 —Al 2 O 3 , noble metals, base metals, or combinations thereof; 
 or both. 
 
     
     
         20 . A method of converting a Fischer-Tropsch product into aromatic compounds comprising:
 providing a Fischer-Tropsch product stream comprising C 5+  normal paraffins;   isomerizing a first portion of the Fischer-Tropsch product stream in an isomerization reaction zone comprising an isomerization reactor in the presence of an isomerization catalyst under isomerization conditions to form an isomerized product stream comprising C 4  to C 20  normal paraffins and isoparaffins and C 20+  hydocarbons;   separating the isomerized product stream into an SPK stream comprising synthetic paraffinic kerosene comprising C 9 -C 16  paraffins, a naphtha stream comprising C 5  to C 8  paraffins, and an unconverted oil stream comprising C 21+  paraffins;   hydrocracking the unconverted oil stream in a hydrocracking reaction zone comprising a hydrocracking reactor in the presence of a hydrocracking catalyst under hydrocracking conditions to form a hydrocracked oil stream comprising C 1  to C 20  isoparaffins and normal paraffins;   passing the hydrocracked oils stream to the isomerization reaction zone;   reforming a second portion of the Fischer-Tropsch product stream comprising C 5  to C 16  normal paraffins in a reforming reaction zone comprising a reforming reactor in the presence of a reforming catalyst under reforming conditions to form an aromatic product stream comprising C 6  to C 16  aromatic compounds.