US2005067122A1PendingUtilityA1

Methods of processing lignocellulosic pulp with cavitation

39
Priority: May 17, 2000Filed: Sep 2, 2004Published: Mar 31, 2005
Est. expiryMay 17, 2020(expired)· nominal 20-yr term from priority
Inventors:Bijan KazemKelly Hudson
B01F 23/23B01F 23/237612B01J 19/1887D21C 9/16B01J 2219/00121B01J 19/1806D21C 9/147D21C 9/153B01F 27/2722D21B 1/30B01J 19/008B01F 23/41
39
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Claims

Abstract

Methods of treating lignocellulosic pulp with cavitation are disclosed. The methods include delignifying pulp contained in a slurry in the presence of cavitation. Delignification can be done by mixing the pulp slurry with an oxidizing agent in a cavitation zone.

Claims

exact text as granted — not AI-modified
1 . A method of processing lignocellulosic pulp comprising: 
 contacting an oxidizing agent with a slurry comprising pulp in the presence of cavitation to produce a delignified pulp.    
     
     
         2 . The method of  claim 1 , wherein the oxidizing agent is non-alkaline.  
     
     
         3 . The method of  claim 1 , wherein the slurry contains about 15% or less by weight dry pulp material.  
     
     
         4 . The method of  claim 1 , wherein the slurry contains about 0.1% to about 15% by weight dry pulp material.  
     
     
         5 . The method of  claim 1 , wherein the slurry contains about 0.1% to about 6% by weight dry pulp material.  
     
     
         6 . The method of  claim 1 , further comprising generating cavitation by moving a body through the slurry.  
     
     
         7 . The method of  claim 1 , further comprising feeding the oxidizing agent and the slurry into a cavitation zone.  
     
     
         8 . The method of  claim 7 , wherein the oxidizing agent and the slurry reside in the cavitation zone for less than about 2 minutes.  
     
     
         9 . The method of  claim 1 , further comprising directing the slurry contacted with oxidizing agent wherein the oxidizing agent and the slurry reside in the cavitation zone for less than about 30 minutes.  
     
     
         10 . The method of  claim 1 , wherein the slurry further comprises black liquor.  
     
     
         11 . The method of  claim 1 , wherein upon contacting the slurry with the oxidizing agent the slurry exhibits a pH in the range of about 9 to about 12.  
     
     
         12 . The method of  claim 1 , wherein the oxidizing agent comprises an oxygen-containing material.  
     
     
         13 . The method of  claim 12 , wherein the oxygen containing material is selected from air, ozone, molecular oxygen, sodium hydroxide, hydrogen peroxide and combinations thereof.  
     
     
         14 . The method of  claim 1 , wherein the slurry exhibits a first Kappa Number and the delignified pulp exhibits a second Kappa Number, wherein the second Kappa Number is at least 5% less than the first Kappa Number.  
     
     
         15 . The method of  claim 1 , wherein the slurry exhibits a first Kappa Number prior to contacting with the oxidizing agent in the presence of cavitation and the delignified pulp exhibits a second Kappa Number and wherein the second Kappa Number is about 5% to about 55% less than the first Kappa Number.  
     
     
         16 . The method of  claim 1 , wherein contacting the oxidizing agent and the slurry in the presence of cavitation occurs under pressure in a range of about 480 kPa to about 1035 kPa.  
     
     
         17 . The method of  claim 1 , further comprising retaining the oxidizing agent and the slurry in a tank after being exposed to cavitation.  
     
     
         18 . The method of  claim 17 , wherein the retaining the oxidizing agent and the slurry in a tank occurs under pressure in a range of about 480 kPa to about 1035 kPa.  
     
     
         19 . The method of  claim 17 , wherein the oxidizing agent and the slurry are retained in the tank in a range of about 1 minute to about 45 minutes.  
     
     
         20 . A method for processing lignocellulosic pulp comprising: 
 delignifying a lignocellulosic pulp in a cavitation zone to produce a delignified pulp.    
     
     
         21 . The method of  claim 20 , wherein delignifying comprises mixing the lignocellulosic pulp with an oxygen in the cavitation zone.  
     
     
         22 . The method of  claim 20 , wherein the oxygen-containing material is selected from air, ozone, molecular oxygen, and combinations thereof.  
     
     
         22 . The method of  claim 20 , wherein the lignocellulosic pulp is contained within a slurry at a concentration of about 15% or less by weight dry lignocellulosic pulp.  
     
     
         23 . The method of  claim 22 , wherein the concentration of the lignocellulosic pulp in the slurry is about 6% or less by weight of dry lignocellulosic pulp.  
     
     
         24 . The method of  claim 20 , wherein delignifying comprises contacting the lignocellulosic pulp with a non-alkaline oxidizing agent.  
     
     
         25 . The method of  claim 24 , wherein the non-alkaline oxidizing agent is selected from air, ozone, molecular oxygen and combinations thereof.  
     
     
         26 . The method of  claim 20 , wherein delignifying occurs under pressure.  
     
     
         27 . The method of  claim 26 , wherein the pressure is in a range of about 480 kPa to about 1035 kPa.  
     
     
         28 . The method of  claim 20 , wherein delignifying occurs in a pH range of about 9 to about 12.  
     
     
         29 . The method of  claim 20 , wherein the lignocellulosic pulp exhibits a first Kappa Number and the delignified pulp exhibits a second Kappa Number, and wherein the second Kappa Number is at least 5% less than the first Kappa Number.  
     
     
         30 . The method of  claim 20 , wherein the lignocellulosic pulp is contained within a slurry that comprises black liquor.  
     
     
         31 . The method of  claim 20 , wherein delignifying comprises retaining the lignocellulosic pulp in a tank under pressure.  
     
     
         32 . The method of  claim 31 , wherein the pressure is in the range of about 480 kPa to about 1035 kPa.  
     
     
         33 . The method of  claim 31 , wherein the lignocellulosic pulp is retained in the tank for up to about 45 minutes.  
     
     
         34 . A method of treating lignocellulosic pulp comprising: 
 mixing a slurry comprising pulp with a non-alkaline oxidizing agent in the presence of cavitation to produce a delignified pulp.    
     
     
         35 . The method of  claim 34 , wherein the non-alkaline oxidizing agent is selected from air, ozone, molecular oxygen and combinations thereof.  
     
     
         36 . The method of  claim 34 , wherein the pH of the slurry during mixing is between about 9 and about 12.  
     
     
         37 . The method of  claim 34 , wherein the cavitation is produced by moving a body through the slurry.  
     
     
         38 . The method of  claim 34 , wherein the slurry further comprises black liquor.  
     
     
         39 . A method of treating lignocellulosic pulp comprising: 
 mixing an oxidizing agent and a slurry containing lignocellulosic pulp in the presence of cavitation to produce a delignified pulp, wherein the mixture of the oxidizing agent and the slurry exhibits a pH above 7.    
     
     
         40 . The method of  claim 39 , wherein the mixture of the oxidizing agent and the slurry exhibits a pH of about 9 to about 12.  
     
     
         41 . The method of  claim 39 , wherein oxidizing agent is non-alkaline.

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