Continuous production of fuel grade hydrocarbons by hydrotreatment of forestry byproduct lignin

Abstract

The present invention relates to a composition and a method of preparing the composition where the composition comprises lignin dissolved in depolymerized lignin obtained from hydrotreatment of lignin. The method may be operated in batch mode or in a continuous mode but there is no need to add any oil.

1 . A composition comprising Kraft lignin having a weight average molecular weight (M w ) of at least 1,000 g/mol dissolved in depolymerized Kraft lignin. 
     
     
         2 . The composition according to  claim 1  wherein the depolymerized lignin is a mixture comprising phenol derivatives and polyphenol derivatives such as an alkylphenol, an alkyl alkoxyphenol or an alkoxyphenol and a diphenol. 
     
     
         3 . The composition according to  claim 1  wherein the concentration of lignin is at least 1 wt %, or at least 3 wt %, or at least 5 wt %, or at least 10 wt %, or at least 15 wt %, or at least 25 wt %, or 40 wt % or less, or 35 wt % or less, or 30 wt % or less of the total weight of the composition. 
     
     
         4 . The composition according to  claim 1  wherein no added carrier liquid is present. 
     
     
         5 . The composition according to  claim 1  wherein the mixture comprises at least 50 wt % of oxygenated compounds. 
     
     
         6 . The composition according to  claim 1  wherein the amount of lignin is 2-20 wt %; wherein the Kraft lignin has a weight average molecular weight (M w ) of higher than 1,500 g/mol but lower than 10,000 g/mol; wherein the amount of depolymerized Kraft lignin is 80-98 wt % and the depolymerized lignin comprises alkylphenols and alkoxy phenols. 
     
     
         7 . The composition according to  claim 1  wherein the boiling point of the depolymerized lignin is at least 220° C., or at least 250° C., or at least 280° C., or at least 300° C., or at least 330° C., or at least 350° C. 
     
     
         8 . The composition  claim 1  wherein the composition is free of any particles having a diameter of 100 μm or more, or 50 μm or more, or 20 μm or more. 
     
     
         9 . The composition according to  claim 1  wherein the depolymerized lignin is obtained by hydrotreatment or by hydrothermal treatment or hydrothermal cracking or solvolysis or any combination thereof. 
     
     
         10 . A method of preparing the composition according to  claim 1  wherein the method comprises:
 a. providing a first feed of Kraft lignin having a weight average molecular weight (M w ) of at least 1,000 g/mol wherein the feed is a solution of Kraft lignin; 
 b. hydrotreating the first feed forming a first product stream comprising light compounds and depolymerized lignin; 
 c. removing the light compounds from the first product stream leaving a second product stream comprising the depolymerized lignin; 
 d. providing a second feed of lignin; and 
 e. mixing the depolymerized lignin with the second feed of lignin. 
 
     
     
         11 . The method according to  claim 10  wherein the first feed of lignin is a mixture of the Kraft lignin and an organic solvent selected from an ester, ether, alcohol, aldehyde, sulfoxide or ketone. 
     
     
         12 . The method according to  claim 10  wherein the hydrotreating step comprises treating the lignin with hydrogen gas or a hydrogen donor. 
     
     
         13 . The method according to  claim 10  wherein the hydrotreating is performed together with a HDS, HDN or HDO catalyst such as a transition metal catalyst such as a Ni, Co, Mo, Zr, Ru, Pt or Pd based catalyst. 
     
     
         14 . The method according to  claim 10  wherein the hydrotreating is performed at a temperature of not more than 500° C., or not more than 400° C., or not more than 300° C., or not more than 200° C., or at 100° C. or higher, or 150° C. or higher. 
     
     
         15 . The method according to  claim 10  wherein the hydrotreating is performed at a pressure of 5 to 400 bar such as 50 bar or higher, or 100 bar or higher, or 300 bar or lower, or 200 bar or lower. 
     
     
         16 . The method according to  claim 15  wherein the hydrotreating is performed at a hydrogen gas pressure of 100-150 bar. 
     
     
         17 . The method according to  claim 10  wherein the first feed of lignin is a mixture of lignin and an alcohol such as phenol. 
     
     
         18 . The method according to  claim 10  wherein the depolymerized lignin comprises compounds having a boiling point of at least 220° C., or at least 250° C., or at least 280° C., or at least 300° C., or at least 330° C., or at least 350° C. 
     
     
         19 . The method according to  claim 10  wherein the mixing of the second product stream and the second feed of lignin is done at a temperature of at least 50° C. or higher, or 70° C. or higher, or 90° C. or higher. 
     
     
         20 . The method according to  claim 10  wherein the depolymerized lignin comprises a mixture comprising phenol derivatives and polyphenol derivatives such as an alkylphenol, an alkyl alkoxyphenol or an alkoxyphenol and a diphenol. 
     
     
         21 . The method according to  claim 10  wherein the feed of lignin provided in step a and d are treated in a pre-treatment step prior to step a and d respectively wherein the pre-treatment is selected from membrane filtration, solvent extraction or acidification and separation or a combination thereof. 
     
     
         22 . The method according to  claim 10  wherein the amount of depolymerized lignin compounds having a boiling point of at least 220° C., or at least 250° C., or at least 280° C., or at least 300° C., or at least 330° C., or at least 350° C., is at least 50 wt %, or at least 60 wt %, or at least 70 wt %, or at least 80 wt %, or at least 90 wt %, or at least 95 wt %. 
     
     
         23 . An intermediate composition comprising Kraft lignin having a weight average molecular weight (M w ) of 1,000 g/mol dissolved in depolymerized lignin. 
     
     
         24 . A The fuel obtained by the method according to  claim 10 .