Apparatuses, methods and systems for yield increase in a kraft cooking plant

Abstract

The APPARATUSES, METHODS AND SYSTEMS FOR APPARATUSES, METHODS AND SYSTEMS FOR YIELD INCREASE IN A KRAFT COOKING PLANT present synergies for at least two parallel cooking plants, e.g., one producing dissolving pulp in a prehydrolysis kraft process, and the other producing kraft pulp by kraft pulping process, which may facilitate increased cooking yield in the kraft cooking plant producing kraft pulp by recovering the hemicelluloses solubilized in the acidic hydrolysate of the prehydrolysis kraft process. In some implementations, there may be no cold caustic extraction step on the dissolving pulp line as the target pulp purity can be achieved by performing just a prehydrolysis step, with reutilization of an acidic hydrolysate stream in a kraft pulp line.

1 .- 25 . (canceled) 
     
     
         26 . A system for producing kraft pulp, comprising:
 a kraft cooking plant; and   an acidic hydrolysate source providing acidic hydrolysate to a kraft cooking process of the kraft cooking plant.   
     
     
         27 . The system of  claim 26 , wherein the acidic hydrolysate source comprises a prehydrolysis kraft process producing dissolving wood pulp. 
     
     
         28 . The system of  claim 26 , wherein wood chips of the kraft cooking plant are impregnated with the acidic hydrolysate prior to an alkaline cooking process. 
     
     
         29 . The system of  claim 28 , wherein kraft cooking plant further comprises:
 an alkaline digester; and   an impregnation vessel preceding the alkaline digester;   wherein the acidic hydrolysate is provided to the impregnation vessel.   
     
     
         30 . The system of  claim 28 , wherein the kraft cooking plant further comprises:
 an alkaline digester comprising an impregnation zone near a top portion of the alkaline digester;   wherein the acidic hydrolysate is provided to the impregnation zone.   
     
     
         31 . The system of  claim 28 , wherein the wood chips are impregnated with the acidic hydrolysate for a duration of between 2 to 180 minutes. 
     
     
         32 . The system of  claim 28 , wherein the wood chips are impregnated with the acidic hydrolysate at a temperature of between 70 to 125° C. 
     
     
         33 . The system of  claim 32 , wherein the wood chips are impregnated with the acidic hydrolysate at a temperature of between 90 to 100° C. 
     
     
         34 . The system of  claim 28 , wherein the kraft cooking plant further comprises:
 an alkaline digester comprising an intermediate alkaline zone;   wherein the acidic hydrolysate is provided to the intermediate alkaline zone.   
     
     
         35 . The system of  claim 34 , wherein the intermediate alkaline zone has a residual effective alkaline concentration of 10 g/l or less. 
     
     
         36 . The system of  claim 34 , wherein the intermediate alkaline zone has a chip retention time of 30 to 90 minutes.