US2017175328A1PendingUtilityA1

Method and apparatus for pumping sawdust feed in a sawdust pulping system

42
Assignee: ANDRITZ INCPriority: Dec 21, 2015Filed: Dec 21, 2016Published: Jun 22, 2017
Est. expiryDec 21, 2035(~9.4 yrs left)· nominal 20-yr term from priority
Inventors:Tyson Bradford Hunt
D21C 3/24D21C 7/06D21C 3/02D21C 7/00
42
PatentIndex Score
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Claims

Abstract

A method of producing chemical cellulose pulp from sawdust utilizing a static down-flow retention vessel comprising the steps of continuously pressurizing a flow of sawdust using a progressive cavity pump to produce a pressurized sawdust feed for a treatment vessel, passing the pressurized sawdust feed at super-atmospheric pressure downwardly in the treatment vessel, adding treatment white black liquor to the treatment vessel, and treating the pressurized sawdust feed in the treatment vessel with treatment white black liquor to form a treated sawdust, and discharging treated sawdust from the treatment vessel.

Claims

exact text as granted — not AI-modified
What is claimed is: 
     
         1 . A method of producing chemical cellulose pulp from sawdust utilizing a static down-flow retention vessel, comprising the steps of continuously:
 using a progressive cavity pump to pressurize a flow of sawdust to produce a pressurized sawdust feed for a treatment vessel;   passing the pressurized sawdust feed at super-atmospheric pressure downwardly in the treatment vessel;   adding treatment white black liquor;   treating the pressurized sawdust feed in the treatment vessel with treatment white black liquor to form a treated sawdust; and   discharging treated sawdust from the treatment vessel.   
     
     
         2 . The method of  claim 1 , wherein the flow of sawdust is maintained at between about 5% and about 20% consistency as said flow of sawdust moves from the progressive cavity pump to the treatment vessel. 
     
     
         3 . The method of  claim 1 , wherein the flow of sawdust is maintained at between about 20% and about 35% consistency as said flow of sawdust moves from the progressive cavity pump to the treatment vessel. 
     
     
         4 . The method of  claim 1 , wherein the flow of sawdust is maintained at between about 5% and about 35% consistency as said flow of sawdust moves from the progressive cavity pump to the treatment vessel. 
     
     
         5 . The method of  claim 1 , wherein the treatment white black liquor is added to a sawdust chute. 
     
     
         6 . The method of  claim 1 , wherein the progressive cavity pump has an outlet. 
     
     
         7 . The method of  claim 6 , wherein the treatment white black liquor is added to the outlet of the progressive cavity pump. 
     
     
         8 . The method of  claim 1 , wherein the treatment white black liquor is added directly to the treatment vessel. 
     
     
         9 . The method of  claim 8 , wherein treatment white black liquor is additionally added to a sawdust chute. 
     
     
         10 . The method of  claim 6 , wherein treatment white black liquor is additionally added to a sawdust chute. 
     
     
         11 . The method of  claim 6 , wherein treatment white black liquor is additionally added directly to the treatment vessel. 
     
     
         12 . The method of  claim 7 , wherein treatment white black liquor is additionally added directly to the treatment vessel. 
     
     
         13 . The method of  claim 7 , wherein treatment white black liquor is additionally added to a sawdust chute. 
     
     
         14 . The method of  claim 1 , wherein no purge steam is added to the progressive cavity pump. 
     
     
         15 . The method of  claim 1 , wherein purge steam is added to the treatment vessel through a digester purge steam upper. 
     
     
         16 . The method of  claim 1 , wherein purge steam is added to the treatment vessel through a digester purge steam lower. 
     
     
         17 . A system for producing chemical pulp from sawdust, comprising:
 a receiving vessel to receive a flow of sawdust;   a feed screw for transporting the flow of sawdust from the receiving vessel to a progressive cavity pump, wherein said progressive cavity pump pressurizes and transports the flow of sawdust to a treatment vessel;   treatment white black liquor fed to the treatment vessel; and   treated sawdust discharged from the treatment vessel.   
     
     
         18 . The system of  claim 17 , wherein the flow of sawdust is maintained at between about 20% and about 35% consistency as said flow of sawdust moves from the progressive cavity pump to the treatment vessel. 
     
     
         19 . The system of  claim 17 , wherein the flow of sawdust is maintained at between about 5% and about 35% consistency as said flow of sawdust moves from the progressive cavity pump to the treatment vessel. 
     
     
         20 . The system of  claim 17 . wherein treatment white black liquor is added to one or more of:
 a sawdust chute, an outlet of the progressive cavity pump, or the treatment vessel.

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