Hydrocarbon feedstock average molecular weight increase

Abstract

The invention deals with hydrocarbon feedstock molecular weight increase via olefin oligomerization and/or olefin alkylation onto aromatic rings. Addition of a purification section allows improved unit working time and lower maintenance.

1 . A method for the treatment of an olefin containing hydrocarbon feedstock, wherein said feedstock successively undergoes (i) selective hydrogenation, (ii) treatment on adsorbent to obtain at least one nitrogen depleted fraction, (iv) at least one middle distillate generation via (iv-a) oligomerization of said nitrogen depleted fraction and/or (iv-b) alkylation of said nitrogen depleted fraction. 
     
     
         2 . A method according to  claim 1 , wherein (v) at least one unreacted material is separated from said at least one middle distillate. 
     
     
         3 . A method according to  claim 2 , wherein said at least one unreacted material is recycled at step (iv) for at least one middle distillate generation. 
     
     
         4 . A method according to  claim 1 , wherein selectively hydrogenated feedstock of step (i) is split into at least two of LCCS, MCCS, HCCS and fuel gas prior to treatment of at least one of the foregoing on adsorbent. 
     
     
         5 . A method according to  claim 1 , wherein said feedstock successively undergoes (i) selective hydrogenation, (ii) splitting into a light cut (LCCS) and a heavier cut (HCCS or mixed MCCS/HCCS), (iii) LCCS treatment on adsorbent to obtain a nitrogen depleted LCCS, (iv) a first middle distillate generation via (iv-a) oligomerization of said nitrogen depleted LCCS and/or (iv-b) alkylation of said nitrogen depleted LCCS. 
     
     
         6 . A method according to  claim 5 , wherein (vi) said first middle distillate is further alkylated with a gasoline cut to produce a second middle distillate. 
     
     
         7 . A method according to  claim 6 , wherein (vii) a second unreacted material is separated from said second middle distillate. 
     
     
         8 . A method according to  claim 7 , wherein said second unreacted material is recycled at step (vii) for said second middle distillate generation. 
     
     
         9 . A method for the treatment of an olefin containing hydrocarbon feedstock according to  claim 1 , wherein said feedstock successively undergoes (i) selective hydrogenation, (ii) splitting into a light cut (LCCS) and a heavier cut (HCCS or mixed MCCS/HCCS), (iii) said LCCS and said HCCS or mixed MCCS/HCCS separate treatment on adsorbent so as to remove nitrogen compounds, to obtain nitrogen depleted LCCS and nitrogen depleted HCCS or mixed MCCS/HCCS, (iv) a third middle distillate generation via (iv-a) oligomerization and/or (iv-b) alkylation of said nitrogen depleted LCCS combined with said nitrogen depleted HCCS or mixed MCCS/HCCS. 
     
     
         10 . A method according to  claim 9 , wherein a gasoline cut is separated from said third middle distillate. 
     
     
         11 . A method for the treatment of an olefin containing hydrocarbon feedstock according to  claim 1 , wherein said feedstock successively undergoes (i) selective hydrogenation, (ii) splitting into a light cut (LCCS) and a heavier cut (HCCS or mixed MCCS/HCCS), (iii) said LCCS and said HCCS or mixed MCCS/HCCS separate treatment on adsorbent so as to remove nitrogen compounds, to obtain nitrogen depleted LCCS and nitrogen depleted HCCS or mixed MCCS/HCCS, (iv-a) a fourth middle distillate generation via oligomerization of said nitrogen depleted LCCS, (iv-b) a fifth middle distillate generation via alkylation of said nitrogen depleted HCCS or mixed MCCS/HCCS. 
     
     
         12 . A method according to  claim 11 , wherein unreacted olefins are separated from said fourth middle distillate. 
     
     
         13 . A method according to  claim 12 , wherein unreacted olefins are recycled at step (iv-a) for fourth middle distillate generation. 
     
     
         14 . A method according to  claim 11 , wherein fourth middle distillate is alkylated with nitrogen depleted HCCS or mixed MCCS/HCCS and an aromatic containing stream at step (iv-b) to produce said fifth middle distillate. 
     
     
         15 . A method according to  claim 14 , wherein unreacted material is separated from said fifth middle distillate. 
     
     
         16 . A method according to  claim 15 , wherein unreacted material is recycled at step (iv-b). 
     
     
         17 . A method according to  claim 1 , wherein said adsorbent comprises one or more of molecular sieves, acidic ion-exchange resins, acid-treated clays, activated aluminas, spent FCC catalysts, MOF (Metal-Organic Framework), ASA, NiMo, and catalysts guard beds. 
     
     
         18 . A method according to  claim 1 , wherein said adsorbent is loaded into a purification section located in a guard bed capacity, which guard bed capacity is operated on a swing cycle with two or three beds, and wherein, respectively, one or two beds in series, are being used on stream for contaminant removal, while the remaining one is on regeneration.