Process for the manufacture of hydrocarbons

Abstract

A feedstock originating from renewable sources is converted to branched and saturated hydrocarbons without heteroatoms in the diesel fuel distillation range by skeletal isomerisation and deoxygenation carried out by hydrodeoxygenation or alternatively by combined decarboxylation and decarbonylation reactions, whereby the consumption of hydrogen is decreased.

1 . Branched saturated hydrocarbons prepared in a process comprising skeletally isomerizing a feedstock comprising unsaturated fatty acids or fatty acid esters with C 1 -C 5  alcohols, or mixtures thereof, and deoxygenating the skeletally isomerized feedstock. 
     
     
         2 . The branched saturated hydrocarbons according to  claim 1 , wherein the feedstock comprises at least 20% by weight of unsaturated fatty acids or fatty acid esters with C 1 -C 5  alcohols. 
     
     
         3 . The branched saturated hydrocarbons according to  claim 1 , wherein the unsaturated fatty acid or fatty acid esters with C 1 -C 5  alcohols used as the feedstock has a total carbon number of 8 to 26. 
     
     
         4 . The branched saturated hydrocarbons according to  claim 1 , wherein the feedstock originates from biological raw materials. 
     
     
         5 . The branched saturated hydrocarbons according to  claim 1 , wherein the skeletal isomerization is carried out at a temperature of 150-400° C., under the pressure of 0-5 MPa. 
     
     
         6 . The branched saturated hydrocarbons according to  claim 1 , wherein the skeletal isomerization is carried out in the presence of an acidic catalyst selected from silico alumino phosphates and zeolites. 
     
     
         7 . The branched saturated hydrocarbons according to  claim 1 , wherein 0-8% by weight of water or C 1 -C 5  alcohol, based on the total reaction mixture, is added to the feedstock. 
     
     
         8 . The branched saturated hydrocarbons according to  claim 1 , wherein after the skeletal isomerization, prehydrogenation is carried out. 
     
     
         9 . The branched saturated hydrocarbons according to  claim 8 , wherein the prehydrogenation is carried out in the presence of a hydrogenation catalyst containing one or more Group VIII and/or VIA metals, at a temperature 50-400° C. under a hydrogen pressure of 0.1-20 MPa. 
     
     
         10 . The branched saturated hydrocarbons according to  claim 8 , wherein when the feedstock comprises fatty acid esters, the prehydrogenation is carried out in the presence of a metal catalyst at 25-30 MPa hydrogen pressure and at temperature of 200-230° C. 
     
     
         11 . The branched saturated hydrocarbons according to  claim 1 , wherein the skeletal isomerization and optional prehydrogenation forms a product which is subjected to deoxygenation, wherein the deoxygenation is carried out by decarboxylation/decarbonylation or hydrodeoxygenation. 
     
     
         12 . The branched saturated hydrocarbons according to  claim 11 , wherein in the decarboxylation and/or decarbonylation, the product and optionally a solvent or a mixture of solvents are brought into contact with an heterogeneous decarboxylation/decarbonylation catalyst selected from supported catalysts containing one or more Group VIII and/or VIA metals of the Periodic System, at a temperature of 100-400° C. under a pressure from atmospheric pressure to 20 MPa of inert gas/hydrogen-mixture. 
     
     
         13 . The branched saturated hydrocarbons according to  claim 12 , wherein the heterogeneous decarboxylation and/or decarbonylation catalyst is Pd on carbon or sulphided NiMo on alumina. 
     
     
         14 . The branched saturated hydrocarbons according to  claim 11 , wherein in the hydrodeoxygenation, the product and optionally a solvent or a mixture of solvents are brought into contact with a hydrogenation catalyst containing metals from Group VIII and/or VIA of the Periodic System under a pressure between 1 and 20 MPa and at a temperature between 200 and 500° C. 
     
     
         15 . The branched saturated hydrocarbons according to  claim 14 , wherein the hydrogenation catalyst is a supported Pd, Pt, Ni, NiMo or a CoMo catalyst and the support is alumina and/or silica. 
     
     
         16 . The branched saturated hydrocarbons according  claim 11 , wherein in the decarboxylation/decarbonylation and/or hydrodeoxygenation, the solvent is selected from the group consisting of hydrocarbons with the boiling range of 150-350° C., and recycled process streams containing hydrocarbons, and mixtures thereof. 
     
     
         17 . The branched saturated hydrocarbons according to  claim 2 , wherein the unsaturated fatty acid or fatty acid esters with C 1 -C 5  alcohols used as the feedstock has a total carbon number of 8 to 26. 
     
     
         18 . The branched saturated hydrocarbons according to  claim 2 , wherein the feedstock originates from biological raw materials. 
     
     
         19 . The branched saturated hydrocarbons according to  claim 3 , wherein the feedstock originates from biological raw materials. 
     
     
         20 . The branched saturated hydrocarbons according to  claim 2 , wherein the feedstock comprises at least 50% by weight of unsaturated fatty acids or fatty acid esters with C 1 -C 5  alcohols.