USE OF FREE FATTY ACIDS PRODUCED FROM BIO-SOURCED OILS & FATS AS THE FEEDSTOCK FOR A STEAMCRACKER
Use of fatty acids produced from a complex mixture of natural occurring oils & fats and/or of triglycerides deriving from said complex mixture as the feedstock of a steamcracker, by mixing the fatty acids with steam in a steam/feedstock ratio of at least 0.2 kg per kg, a coil outlet temperature of at least 700° C. and an coil outlet pressure of at least 1.2 bara in order to obtain cracking products including bio-ethylene, bio-propylene, bio-butadiene, bio-isoprene, bio-cyclopentadiene and bio-piperylenes, bio-benzene, bio-toluene, bio-xylene and bio-gasoline.
1 . Use of fatty acids produced from a complex mixture of natural occurring oils & fats and/or of triglycerides deriving from said complex mixture as the feedstock of a steamcracker, by mixing the fatty acids with steam in a steam/feedstock ratio of at least 0.2 kg per kg, a coil outlet temperature of at least 700° C. and an coil outlet pressure of at least 1.2 bara in order to obtain cracking products including bio-ethylene, bio-propylene, bio-butadiene, bio-isoprene, bio-cyclopentadiene and bio-piperylenes, bio-benzene, bio-toluene, bio-xylene and bio-gasoline.
2 . Use according to claim 1 , wherein said complex mixture of natural occurring oils & fats is selected among inedible oils, animal fats, highly saturated oils, waste food oils, by-products of the refining of vegetable oils, and mixtures thereof.
3 . Use according to claim 1 , wherein said fatty acids are the only feedstock of the steamcracker.
4 . Use according to claim 1 , wherein said fatty acids are introduced in the steamcracker as mixed with at least a conventional feedstock selected among LPG, naphtha and gasoil.
5 . Use according to anyone of claim 1 , wherein said fatty acids have been obtained by steam distillation or vacuum distillation of said complex mixture.
6 . Use according to anyone of claim 1 wherein said fatty acids have been obtained by hydrolysis of triglycerides to make glycerol and fatty acids and removal of glycerol.
7 . Use according to claim 6 wherein the hydrolysis has been carried out thermally.
8 . Use according to claim 6 wherein the hydrolysis has been carried out catalytically.
9 . Use according to anyone of claim 6 , wherein said triglycerides consist substantially of the solid triglycerides fraction, obtained by segregation of fats & oils into a substantially liquid triglyceride fraction and a substantially solid triglyceride fraction by winterisation or dry fractionation and the solid triglyceride fraction is hydrolysed into fatty acids and glycerol and the glycerol removed.
10 . Use according to anyone of claim 1 , wherein the fatty acids are hydrogenated to obtain substantially saturated fatty acids.
11 . Use according anyone of claim 1 , wherein the triglycerides are hydrogenated to obtain triglycerides with substantially saturated fatty acids moieties.
12 . Process for steam cracking a feedstock as defined in anyone of the preceding claims, wherein said feedstock is mixed with steam and the mixture is heated up to a temperature of 750-900° C. at a pressure of 1.3-2.0 bara.
13 . Process according to claim 1 wherein in the steamcracking process the hydrocarbon feedstock is mixed with steam in a ratio of 0.3 to 0.5 kg steam per kg hydrocarbon feedstock.
14 . Process according to claim 13 wherein in the steamcracking process the hydrocarbon feedstock is mixed with steam in a ratio of 0.3 to 0.45 kg steam per kg hydrocarbon feedstock.
15 . The process of claim 14 wherein the hydrocarbon feedstock is mixed with steam in a ratio of 0.3 to 0.4 kg steam per kg hydrocarbon feedstock.
16 . The process for steam cracking a feedstock as defined in any one of claim 12 , wherein the mixture is heated up to a temperature of 750-950° C. at a residence time of 0.05 to 0.5 seconds.
17 . The process for steam cracking a feedstock as defined in claim 16 , wherein the mixture is heated up to a temperature of 750-950° C. at a residence time of 0.05 to 0.15 seconds.