Apparatus and method for hydrolysis of cellulosic material in a two-step process

Abstract

A system and method for extracting pentose from a slurry of cellulosic material comprising cellulose, water, and optionally acid in a two-stage process.

1 . A system for extracting pentose from a slurry of cellulosic material comprising cellulose, water, and optionally acid, the system comprising
 (i) an inlet adapted to receive the slurry at a top of a vessel;   (ii) a first stage in which the slurry is exposed to a first temperature between 130° C. and 190° C. for a first period of time ranging between 10 minutes and 120 minutes,   (iii) a first extraction screen and a first extraction line operatively connected to the first extraction screen that removes a first liquid containing C 5  sugars from the slurry,   (iv) a second stage in which the slurry is exposed to a second temperature between 100° C. and 170° C. for a second period of time ranging between 30 minutes and 120 minutes,   (v) a second extraction screen and a second extraction line operatively connected to the second extraction screen that removes a second liquid containing C 5  sugars and hemicellulose from the slurry, and   (vi) an outlet adapted to remove the slurry from a bottom of a vessel.   
     
     
         2 . The system according to  claim 1 , wherein a single vessel comprises the first and second stages. 
     
     
         3 . The system according to  claim 1 , wherein a first vessel comprises the first stage and a second vessel comprises the second stage. 
     
     
         4 . The system according to  claim 1 , wherein second temperature is between 140° C. and 160° C. 
     
     
         5 . The system according to  claim 1 , wherein the slurry comprises acid and the first temperature is between 130° C. and 170° C. 
     
     
         6 . The system according to  claim 1 , wherein the slurry does not comprise acid and the first temperature is between 170° C. and 190° C. 
     
     
         7 .- 11 . (canceled)