Aliphatic gasoline component and process to prepare said gasoline component

Abstract

An aliphatic gasoline component comprising more than 90 wt % of a mixture of trimethyl substituted compounds and monomethyl substituted compounds in a weight ratio of trimethyl to monomethyl compounds of at least 0.03 and wherein the compounds may be paraffins and olefins. The invention is also directed to a process to prepare an aliphatic gasoline component by (a) contacting a Fischer-Tropsch synthesis product with a catalyst system comprising a catalyst, which catalyst comprises an acidic matrix and a large pore molecular sieve in a riser reactor at a temperature of between 450 and 650° C. at a contact time of between 1 and 10 seconds and at a catalyst to oil ratio of between 2 and 20 k.g/kg, (b) isolating from the product of step (a) a gasoline fraction and a fraction comprising iso-butane and isobutylene; (c) subjecting the iso-butane and the iso-butylene obtained in step (b) to an alkylation step to prepare a trimethyl substituted pentane, and (d) combining the gasoline fraction obtained in step (b) with the product rich in trimethyl substituted pentane as obtained in step (c).

1 . An aliphatic gasoline component comprising more than 90 wt % of a mixture of trimethyl substituted compounds and monomethyl substituted compounds in a weight ratio of trimethyl to monomethyl compounds of at least 0.03 and wherein the compounds may be paraffins and olefins.  
   
   
       2 . A gasoline component according to  claim 1 , wherein the weight ratio of trimethyl to monomethyl compounds is at most 0.3.  
   
   
       3 . A gasoline fuel according to  claim 1 , wherein the content of 2,2,4-trimethylpentane is between 2 and 20 wt %.  
   
   
       4 . A gasoline fuel composition comprising the aliphatic gasoline component according to  claim 1 , having one or more additives, an aromatics content of between 1 and 22 vol % (as measured by ASTM D5580-95), a motor octane number of greater than 90 and a sulphur content of below 15 ppm by weight (as measured by ASTM D5453-93).  
   
   
       5 . A process Process to prepare an aliphatic gasoline component comprising 
 (a) contacting a Fischer-Tropsch synthesis product with a catalyst system comprising a catalyst, which catalyst comprises an acidic matrix and a large pore molecular sieve in a riser reactor at a temperature of between 450 and 650° C. at a contact time of between 1 and 10 seconds and at a catalyst to oil ratio of between 2 and 20 kg/kg;    (b) isolating from the product of step (a) a gasoline fraction and a fraction comprising iso-butane and iso-butylene;    (c) subjecting the iso-butane and the iso-butylene obtained in step (b) to an alkylation step to prepare a trimethyl substituted pentane; and 
 (d) combining the gasoline fraction obtained in step (b) with the trimethyl substituted pentane as obtained in step (c).  
   
   
   
       6 . The process according to  claim 5 , wherein the feed used in step (a) has a weight ratio of compounds having at least 60 or more carbon atoms and compounds having at least 30 carbon atoms of at least 0.2 and wherein at least 30 wt % of the compounds have at least 30 carbon atoms.  
   
   
       7 . The process according to  claim 6 , wherein at least 50 wt % of the compounds in the feed to step (a) have at least 30 carbon atoms.  
   
   
       8 . The process according to  claim 7 , wherein the weight ratio of compounds having at least 60 or more carbon atoms and compounds having at least 30 carbon atoms in the Fischer-Tropsch product is at least 0.4 in the feed to step (a).  
   
   
       9 . The process according to  claim 5 , wherein the temperature in step (a) is below 600° C.  
   
   
       10 . The process according to  claim 5 , wherein the acidic matrix is alumina.  
   
   
       11 . The process according to  claim 5 , wherein the large pore molecular sieve is of the Faujasite type.  
   
   
       12 . The process according to  claim 5 , wherein the catalyst system in step (a) also comprises zeolite beta, Erionite, Ferrierite, ZSM-5, ZSM-11, ZSM-12, ZSM-22, ZSM-23 or ZSM-57.  
   
   
       13 . The process according to  claim 5 , wherein the Fischer-Tropsch synthesis product used as feed in step (a) is obtained by means of a cobalt-catalyzed Fischer-Tropsch synthesis process.  
   
   
       14 . The process according to  claim 13 , wherein the cobalt catalyst is obtained by (aa) mixing (1) titania or a titania precursor, (2) a liquid, and (3) a cobalt compound, which is at least partially insoluble in the amount of liquid used, to form a mixture; (bb) shaping and drying of the mixture thus obtained; and (cc) calcination of the composition thus obtained.