Methods and Systems for Biomass Conversion to Carboxylic Acids and Alcohols

Abstract

The disclosure includes a method, process and apparatus for the conversion of biomass to carboxylic acids and/or primary alcohols. The system may include a pretreatment/fermentation subsystem operable to produce a fermentation broth containing carboxylic acid salts from biomass, such as lignocellulosic biomass. The system may also include a dewatering subsystem operable to remove excess water from the fermentation broth to produce a concentrated product. The system may also includes an acid springing subsystem operable to produce a mixed carboxylic acid product. The system may also include a hydrogenation subsystem operable to produce an alcohol mixture, such as a mixture containing primary alcohols. Methods of operating this system or other systems to obtain a carboxylic acid or alcohol mixture are also provided.

1 . A system for the conversion of biomass comprising:
 a pretreatment/fermentation subsystem operable to:
 pretreat biomass with lime or quick lime and air to produce treated biomass; and 
 ferment the treated biomass with an inoculum to produce a fermentation broth containing carboxylic acid salts; 
   a dewatering subsystem operable to:
 remove excess water from the fermentation broth to produce a concentrated product; and 
   an acid springing subsystem operable to:
 combine the concentrated product with a low-molecular-weight tertiary amine or ammonia to produce a low-molecular-weight tertiary amine or ammonia carboxylate product from the carboxylic acid salts; 
 replace the low-molecular-weight tertiary amine or ammonia in the low-molecular-weight tertiary amine or ammonia carboxylate product with a high-molecular-weight tertiary amine to form a high-molecular-weight tertiary amine carboxylate product; and 
 thermally break the amine-carboxylate bonds in the high-molecular-weight tertiary amine carboxylate product to produce a mixed carboxylic acid product. 
   
     
     
         2 . A system according to  claim 1 , further comprising a hydrogenation sub system operable to:
 combine the mixed carboxylic acid produce with a high-molecular-weight alcohol to form an ester;   convert the ester to an alcohol mixture using a hydrogenation catalyst; and   separate the alcohol mixture from the high-molecular-weight alcohol.   
     
     
         3 . A system according to  claim 1 , where the biomass comprises lignocellulosic biomass. 
     
     
         4 . A system according to  claim 1 , wherein the pretreatment/fermentation subsystem further comprises:
 a pit having:
 a liner; 
 gravel placed on the liner; and 
 a perforated drain pipe embedded in the gravel; 
   a biomass pile located on top of the pit;   a cover over the biomass pile; and   a pump operable to circulate water from the pit to the top of the biomass pile.   
     
     
         5 . A system according to  claim 4 , wherein the pretreatment/fermentation subsystem further comprises:
 a blower operable to circulate air through the biomass pile; and   a lime water slurry operable to remove carbon dioxide from the air.   
     
     
         6 . A system according to  claim 1 , wherein the inoculum comprises a salt-tolerant microorganism. 
     
     
         7 . A system according to  claim 1 , wherein the dewatering subsystem further comprises:
 a high-molecular-weight carboxylic acid added to the fermentation broth to produce acidified fermentation broth; and   an evaporator operable to concentrate the acidified fermentation broth.   
     
     
         8 . A system according to  claim 7 , wherein the high-molecular-weight carboxylic acid comprises caproic acid, valeic acid or hepotanoic acid. 
     
     
         9 . A system according to  claim 1 , wherein the acid springing subsystem further comprises:
 a mixer to operable to mix the concentrated product with the low-molecular-weight tertiary amine or ammonia and carbon dioxide;   a column operable to exchange the low-molecular-weight tertiary amine or ammonia in the low-molecular-weight tertiary amine or ammonia carboxylate product for a high-molecular-weight tertiary amine; and   a column operable to thermally break the amine-carboxylate bonds in the high-molecular-weight tertiary amine carboxylate product to produce a mixed carboxylic acid product.   
     
     
         10 . A system according to  claim 1 , wherein the low-molecular-weight tertiary amine comprises triethyl amine. 
     
     
         11 . A system according to  claim 1 , wherein the high-molecular-weight tertiary amine comprises trioctyl amine or triethanol amine. 
     
     
         12 . A system according to  claim 2 , wherein the hydrogenation subsystem further comprises:
 a column operable to combine the mixed carboxylic acid produce with a high-molecular-weight alcohol to form an ester;   a hydrogenation reactor operable to convert the ester to an alcohol mixture using a hydrogenation catalyst; and   a column operable to separate the alcohol mixture from the high-molecular-weight alcohol.   
     
     
         13 . A system according to  claim 2 , wherein the high-molecular-weight alcohol comprises heptanol. 
     
     
         14 . A system according to  claim 2 , wherein the alcohol mixture substantially comprises primary alcohols. 
     
     
         15 . A system according to  claim 1 , further comprising the system operable to recycle process heat within at least one subsystem or from one subsystem to another. 
     
     
         16 . A system according to  claim 1 , further comprising the system operable to recycle water within at least one subsystem or from one subsystem to another. 
     
     
         17 . A system according to  claim 1 , further comprising the system operable to recycle lime or quick lime within at least one subsystem or from one subsystem to another. 
     
     
         18 . A system for the conversion of biomass comprising:
 a pretreatment/fermentation means operable to:
 pretreat biomass with lime or quick lime and air to produce treated biomass; and 
 ferment the treated biomass with an inoculum to produce a fermentation broth containing carboxylic acid salts; 
   a dewatering means operable to:
 remove excess water from the fermentation broth to produce a concentrated product; and 
   an acid springing means operable to:
 combine the concentrated product with a low-molecular-weight tertiary amine or ammonia to produce a low-molecular-weight tertiary amine or ammonia carboxylate product from the carboxylic acid salts; 
 replace the low-molecular-weight tertiary amine or ammonia in the low-molecular-weight tertiary amine or ammonia carboxylate product with a high-molecular-weight tertiary amine to form a high-molecular-weight tertiary amine carboxylate product; and 
 thermally break the amine-carboxylate bonds in the high-molecular-weight tertiary amine carboxylate product to produce a mixed carboxylic acid product. 
   
     
     
         19 . A system according to  claim 18 , further comprising a hydrogenation means operable to:
 combine the mixed carboxylic acid produce with a high-molecular-weight alcohol to form an ester;   convert the ester to an alcohol mixture using a hydrogenation catalyst; and   separate the alcohol mixture from the high-molecular-weight alcohol.   
     
     
         20 . (canceled) 
     
     
         21 . A method of obtaining a fermentation product comprising:
 treating a pile of biomass with lime or quick lime, water, an inoculum and air to produce a fermentation broth,   acidifying the fermentation broth with a high-molecular-weight carboxyllic acid to produce acidified fermentation broth;   stripping the fermentation broth in a stripping column to produce stripped fermentation broth;   concentrating the stripped fermentation broth in an evaporator to produce concentrated product;   mixing the concentrated product with a low-molecular-weight tertiary amine or ammonia and carbon dioxide to produce a low-molecular-weight tertiary amine or ammonia carboxylate;   exchanging the low-molecular-weight tertiary amine or ammonia carboxylate with a high-molecular-weight tertiary amine to produce a high-molecular-weight tertiary amine carboxylate;   heating the high-molecular-weight tertiary amine carboxylate to a temperature sufficient to break acid/amine bonds to produce a free carboxylic acid product; and   recovering the free carboxylic acid product;   
       further comprising:
 combining the carboxylic acid produce with a high-molecular-weight alcohol to from an ester; 
 hydrogenating the ester to form an alcohol product; 
 separating the high-molecular-weight alcohol from the alcohol product; and 
 recovering the alcohol product. 
 
     
     
         22 . (canceled) 
     
     
         23 . (canceled)