Process for recovering salt during a lignocellulosic conversion process

Abstract

The present invention relates to a process for generating steam and recovering salts during a lignocellulosic conversion process. The process comprises de-salting a still bottoms stream; incinerating a stream comprising lignin and the de-salted still bottoms stream in an incinerator; and utilizing the heat generated from said incinerating to produce steam. Further provided is a process that comprises feeding a concentrated still bottoms stream to a crystallizer and forming insoluble solids therein comprising salts. Furthermore, the invention relates to a process for recovering salts from a lignocellulosic conversion process, which process comprises the addition of solvent to a still bottoms stream to precipitate salts therefrom. Also provided is a still bottoms composition, a fertilizer product and a composition for incineration.

1 .- 17 . (canceled) 
     
     
         18 . A process for recovering fertilizer from a still bottoms stream resulting from a lignocellulosic conversion process, said process comprising the steps of:
 (i) removing water from the still bottoms stream to produce a concentrated still bottoms stream;   (ii) feeding the concentrated still bottoms stream to a crystallizer;   (iii) forming insoluble solids in the crystallizer by addition of an alcohol;   (iv) producing a fertilizer from the insoluble solids;   (v) recovering the alcohol in one or more stages, thereby producing recovered alcohol; and   (vi) recycling the recovered alcohol in the process.   
     
     
         19 . The process of  claim 18 , wherein a stream comprising de-salted still bottoms is withdrawn from the crystallizer and incinerated in an incinerator. 
     
     
         20 . The process of  claim 19 , wherein a stream comprising lignin is obtained from the process and combusted in an incinerator. 
     
     
         21 . The process of  claim 18 , wherein the insoluble solids are dried prior to the step of producing a fertilizer. 
     
     
         22 . The process of  claim 18 , wherein the fertilizer comprises mixed salts. 
     
     
         23 . The process of  claim 22 , wherein the mixed salts are at least partially composed of struvite. 
     
     
         24 . A process for obtaining salt from a still bottoms stream resulting from a lignocellulosic conversion process to produce an alcohol, said process comprising the steps of:
 (i) processing a lignocellulo sic feedstock to produce fermentable sugar;   (ii) fermenting the sugar with microorganisms to produce a fermentation broth comprising alcohol;   (iii) recovering the alcohol from the fermentation broth in one or more stages to produce an alcohol-enriched mixture and the still bottoms stream that comprises one or more salts; and   (iv) recovering the one or more salts by precipitation with alcohol.   
     
     
         25 . The process of  claim 24 , wherein a mixture of salts are recovered by the precipitation with alcohol. 
     
     
         26 . A still bottoms composition resulting from a lignocellulosic conversion process, said composition comprising an aqueous component, a solvent that is soluble in water and insoluble solids comprising at least inorganic salts originating from the lignocellulosic feedstock and optionally inorganic salts originating from the addition of acid or alkali during said lignocellulosic conversion process. 
     
     
         27 . A fertilizer product isolated from the still bottoms composition of  claim 26 . 
     
     
         28 . A composition for incineration resulting from a lignocellulosic conversion process, said composition comprising de-salted still bottoms and lignin.