Integrated Process for Producing Diesel Fuel from Biological Material and Products and Uses Relating to Said Process

Abstract

The present invention relates to an integrated process for producing diesel fuel or fuel additive from biological material by producing paraffins by a Fischer-Tropsch reaction on one hand and by a catalytic hydrodeoxygenation of bio oils and fats on the other hand. Two hydrocarbon streams, which both comprises predominately hydrocarbons of a certain chain length are treated separately and finally combined and distilled together. The invention also relates to the use of by-products of the wood-processing industry for producing diesel fuel and to a method for narrowing the chain length distribution of Fischer-Tropsch derived diesel fuel. The invention provides a high-quality middle distillate fraction from various biological sources and most preferably from by-products of the wood-processing industry.

1 . An integrated process for producing diesel fuel from biological material, characterized by the steps of
 a. separating hydrocarbons of different chain length of Fischer-Tropsch paraffins of biological origin   b. providing a first hydrocarbon stream comprising an increased proportion of diesel hydrocarbon C 11  to C 20  paraffins formed by treating C 21 -C 100+  hydrocarbons of said Fischer-Tropsch paraffins by catalytic cracking/isomerization,   c. providing a second hydrocarbon stream comprising a first fraction of predominantly C 15  to C 18  hydrocarbons by catalytic hydrodeoxygenation of biological hydrocarbons and a second fraction of C 5 -C 20  hydrocarbons of said Fischer-Tropsch paraffins,   d. mixing said first and second hydrocarbon streams,   e. fractionating the resulting mixed hydrocarbon stream, and   f. recovering a middle distillate fraction.   
     
     
         2 . The process according to  claim 1 , wherein said first hydrocarbon stream is provided by gasification of biomass feedstock to provide synthesis gas; FischerTropsch reaction of said synthesis gas to provide C 1 -C 100+  paraffins; separating C 1 -C 4  paraffins, C 5 -C 20  paraffins and C 21 -C 100+  paraffins; removing said C 1 -C 4  paraffins and said C 5 -C 20  paraffins; and cracking/isomerization of the resulting C 21 -C 100+  paraffins to increase the proportion of diesel hydrocarbon C 11 -C 20  paraffins in the resulting first hydrocarbon stream. 
     
     
         3 . The process according to  claim 1 , wherein said second hydrocarbon stream is provided by hydrodeoxygenation of said biological hydrocarbon feedstock to provide a stream of saturated predominantly C 15  to C 18  paraffins and by an optional hydrodeoxygenation of said C 5 -C 20  paraffins; and non-cracking hydroisomerization of said paraffins to increase the proportion of i-paraffins in the resulting second hydrocarbon stream. 
     
     
         4 . The process according to  claim 1 , wherein 3 to 95% of said first and 5% to 97% of said second hydrocarbon streams are combined in a separator, in which the resulting mixed stream is fractionated into a middle distillate comprising C 11 -C 20  hydrocarbons and a light fraction comprising hydrogen and C 1 -C 4  hydrocarbons, and said middle distillate is recovered for use as diesel fuel. 
     
     
         5 . The process according to  claim 4 , wherein a heavy fraction comprising C 21 -C 100+  hydrocarbons and a naphtha fraction comprising C 5 -C 10  hydrocarbons is also recovered. 
     
     
         6 . The process according to  claim 5 , wherein at least a part of said heavy fraction is recirculated to said cracking/isomerization to be cracked and hydroisomerized to increase the amount of C 11 -C 20  hydrocarbons in said first hydrocarbon stream. 
     
     
         7 . The process according to  claim 1 , wherein said fractionation is set to provide a distillate fraction consisting essentially of C 15  to C 18  hydrocarbons. 
     
     
         8 . The process according to  claim 1 , wherein the biological origin of said FischerTropsch paraffins comprise biomass selected from virgin and waste materials of plant, animal and/or fish origin, and wherein said biological hydrocarbons are based on oils, fats and/or waxes of plant, animal and/or fish origin. 
     
     
         9 . The process according to  claim 8 , wherein said biomass is selected from municipal waste, industrial waste or by-products, agricultural waste or by-products, waste or by-products of the wood-processing industry, waste or by-products of the food industry, marine plants and combinations thereof. 
     
     
         10 . The process according to  claim 1 , wherein said process is operated in connection with a wood-processing industry and the biological feeds to said integrated process originate in or as by-products or waste of said wood-processing industry. 
     
     
         11 . The process according to  claim 10 , wherein the biological origin of said FischerTropsch paraffins comprise waste or by-product(s) of the wood-processing industry and said biological hydrocarbons of said second hydrocarbon stream comprise tall oil or tall oil fatty acids. 
     
     
         12 . The process according to  claim 10 , wherein said wood-processing industry comprises a Kraft mill producing crude tall oil and/or tall oil fatty acids. 
     
     
         13 . The process according to  claim 10 , wherein water produced in the integrated fuel process is supplied to said wood-processing industry for purification and wherein sulphur freed in said fuel process is fed to the sulphur circulation of said wood-processing industry. 
     
     
         14 . The process according to anyone of the preceding claims, wherein said integrated fuel process is further integrated with a pulp and paper mill and wherein waste and/or by-products of said pulp and paper mill are utilized as raw materials for said fuel process and wherein wastes and energy from said fuel process are handled and/or utilized in unit operations of said pulp and paper mill. 
     
     
         15 . Use of lignocellulosic material for producing diesel fuel from purely biorenewable sources, characterized by the steps wherein
 a. lignocellulosic material is gasified and used to provide Fischer-Tropsch paraffins, which are separated into fractions of hydrocarbons of different chain length,   b. a fraction comprising C21-CJOO+ hydrocarbons of said Fischer-Tropsch paraffins is then cracked under isomerizing conditions to provide a first hydrocarbon stream,   c. a first fraction comprising biological hydrocarbons which are hydrodeoxygenated to provide a predominantly C 15  to C 18  paraffin stream and a second fraction comprising C 5 -C 20  hydrocarbons of said Fischer-Tropsch paraffins which is optionally hydrodeoxygenated; are optionally isomerized under non-cracking conditions to provide a second hydrocarbon stream,   d. the two streams are combined and fractionated, and   e. a middle distillate fraction is recovered.   
     
     
         16 . The use according to  claim 15  characterized in that said lignocellulosic material is waste and/or by-products of the wood-processing industry. 
     
     
         17 . A method for narrowing the chain length distribution of a Fischer-Tropsch derived diesel fuel, characterized by the steps of
 a. combining Fischer-Tropsch derived C 5 -C 20  biological hydrocarbons with predominantly C 15  to C 20  hydrocarbons obtained by hydrodeoxygenation of biological hydrocarbons to provide a hydrocarbon stream,   b. combining this hydrocarbon stream with a Fischer-Tropsch derived hydrocarbon stream of C 21 -C 100+  biological hydrocarbons which is cracked under isomerizing conditions,   c. fractionating the combined hydrocarbon stream, and   d. recovering a fraction of C 11 -C 20  hydrocarbons.   
     
     
         18 . The method according to  claim 17 , wherein the recovered fraction contains at least 25% and preferably about 40% to 80% or more of C 15  to C 18  hydrocarbons. 
     
     
         19 . A biological middle distillate fraction obtainable by anyone of the processes according to  claims 1  to  14  from a mixed hydrocarbon stream comprising from 3 to 95% of a first Fischer-Tropsch derived hydrocarbon stream having an increased amount of carbon atoms between 11 and 20 and from 5 to 97% of a second hydrocarbon stream having predominantly 15 to 18 carbon atoms. 
     
     
         20 . The middle distillate fraction according to  claim 19 , wherein said fraction contains at least 25% and preferably about 40% to 80% or more of C 15  to C 18  hydrocarbons. 
     
     
         21 . Use of the biological middle distillate fraction obtained according to  claim 1  as an additive for improving the cetane value of a fuel produced by other means. 
     
     
         22 . The use according to  claim 21 , wherein said fraction is also used for improving the cloud point and/or pour point of said fuel produced by said other means.