Process for the comminution of materials and plants for carrying out the process

Abstract

A process for the comminution, in particular defibrillation, and reaction of fibrous materials having a high dry solids content with the addition of a circulating medium, preferably a carrier gas and/or reaction agent, as well as optionally of chemicals. The invention is mainly characterized in that the circulating medium is recycled after leaving the comminuting device, by changing its temperature, and is then recycled to the comminuting device. Another embodiment of the invention is characterized in that the fibrous materials and liquid reaction agent are separated from the carrier gas and reaction agent vapors, which are then recycled back to comminuting device. A plant for carrying out this process is mainly characterized in that the comminuting device and route for recycling and treatment of the circulating medium form a closed system.

What is claimed is: 
     
       1. A process for treating high consistency fibrous materials, which comprises contacting fibrous material, a reaction agent and a carrier gas in a comminuting zone under a closed system to separate said fibrous material into smaller segments and react with said reaction agent;   passing said segmented fibrous material, reaction agent and carrier gas to a reaction zone for further reaction between said segmented fibrous material and said reaction agent;   separating said reaction agent in a liquid phase from said carrier gas to produce a remaining gaseous fraction including vapors of said reaction agent;   separating said gaseous fraction of said reaction agent and said carrier gas from said reaction zone and recycling said gaseous fraction to said comminuting zone for further reaction;   and discharging reacted, segmented fibrous material from said reaction zone.   
     
     
       2. The process of claim 1, wherein said reaction agent is hydrogen peroxide. 
     
     
       3. The process of claim 1, wherein said recycled gaseous fraction is passed through a heat exchange zone prior to introduction into said comminuting zone. 
     
     
       4. The process of claim 1, wherein said reaction agent is hydrogen peroxide, and the recycled gaseous fraction contains hydrogen peroxide vapors. 
     
     
       5. The process of claim 1, wherein said comminuting zone comprises means for comminuting fibers and said recycled gaseous fraction is introduced into said comminuting zone on two, opposed sides of said comminuting means. 
     
     
       6. The process of claim 5, wherein said comminuting means comprises at least one grinding plate means. 
     
     
       7. A process according to claim 1 wherein said high consistency fibrous materials has a consistency range between about 20% and 60%.   
     
     
       8. A process for treating high consistency fibrous materials, which comprises contacting fibrous material, a reaction agent and a carrier gas in a comminuting zone under a closed system to separate said fibrous material into smaller segments and react with said reaction agent;   passing said segmented fibrous material, reaction agent and carrier gas to a reaction zone for further reaction between said segmented fibrous material and said reaction agent;   separating a gaseous fraction of said reaction agent and said carrier gas from said reaction zone and recycling said gaseous fraction to said comminuting zone for further reaction; and   discharging reacted, segmented fibrous material from said reaction zone;   wherein said reaction agent is NO x , with x being an integer between 1 and 3, inclusive, and said carrier gas is carbon dioxide.   
     
     
       9. A process for treating high consistency fibrous materials, the process comprising contacting fibrous material, a reaction agent and a carrier gas in a comminuting zone under a closed system to separate said fibrous material into smaller segments and react with said reaction agent;   passing said segmented fibrous material, reaction agent and carrier gas to a reaction zone for further reaction between said segmented fibrous material and said reaction agent;   separating a gaseous fraction of said reaction agent and said carrier gas from said reaction zone and recycling said gaseous fraction to said comminuting zone for further reaction;   discharging reacted, segmented fibrous material from said reaction zone; and   cooling said gaseous fraction in a heat exchange zone before recycling said gaseous fraction;   wherein said reaction agent is separated in the liquid phase from said carrier gas to produce said gaseous fraction including vapors of said reaction agent.   
     
     
       10. A process according to claim 1, wherein said reaction agent is hydrogen peroxide, said carrier gas is air, and said gaseous fraction being recycled contains hydrogen peroxide vapors and air. .Iadd. 
     
     
       11.  A process for treating high consistency fibrous materials comprising the steps of contacting a high consistency fibrous material having a consistency of about 20% to 60% with a carrier gas and a reactant consisting essentially of ozone in a feed zone and feeding said fibrous material, ozone and carrier gas together to an inlet of a fluffer,   said fluffer comprising a stator grinding plate having a central opening defining said inlet of said fluffer, a rotating grinding plate opposing said stator grinding plate, and an outlet radially spaced from said inlet,   feeding said fibrous material, ozone and carrier gas into said inlet axially with respect to an axis of rotation of said rotating grinding plate,   passing said fibrous material, ozone and carrier gas in a substantially radial direction from said inlet and through a comminuting and reaction zone between said grinding plates of said fluffer towards an outlet and fluffing said fibrous material while in continuous contact with said ozone to produce simultaneously a partially reacted and fluffed fibrous material,   passing said fluffed fibrous material, ozone and carrier gas to a second reaction zone for further reaction,   separating unreacted ozone and carrier gas from said second reaction zone, and   discharging said fibrous material from said second reaction zone..Iaddend..Iadd.12. The process of claim 11, comprising   recovering said ozone from said second reaction zone and recycling said ozone to said fluffer..Iaddend..Iadd.13. The process of claim 12, comprising   cooling said ozone to about 20° C. to 40° C. before recycling..Iaddend..Iadd.14. The process of claim 11, comprising   recovering said ozone from said second reaction zone,   recycling said ozone onto a rear face of said rotating grinding plate, and   mixing said recycled ozone with said fluffed fibrous material..Iaddend..Iadd.15. The process of claim 14, further comprising   cooling said recycled ozone and introducing said recycled ozone to said fluffer to cool said grinding plates and said fibrous material..Iaddend..Iadd.16. The process of claim 11, further comprising   recovering ozone from said second reaction zone,   cooling said recovered ozone, and   recycling said cooled ozone to said fibrous material to cool said fibrous   
     
     
        material before feeding to said inlet of said fluffer..Iaddend..Iadd.17. The process of claim 11, wherein said stator grinding plate and said rotating grinding plate are positioned to receive said fibrous material and ozone, and said process comprises feeding said fibrous material and ozone substantially downwardly into said fluffer..Iaddend..Iadd.18. The process of claim 11, further comprising   passing said unreacted ozone and carrier gas from said second reaction zone to an ozone generator and increasing the ozone concentration in said carrier gas,   cooling said ozone and carrier gas to about 20° C. to 40° C., and   introducing said cooled ozone and carrier gas to said fluffer, and reacting   
     
     
        said ozone with said fibrous material..Iaddend..Iadd.19.  The process of claim 11, wherein prior to said contacting step, said process comprises conveying said fibrous material through a sealed screw feeder and discharging said fibrous material to an inlet chute of said fluffer..Iaddend..Iadd.20. The process of claim 11, comprising   feeding said fibrous material to a screw feeder prior to feeding to said fluffer and conveying and discharging said fibrous material from said screw feeder into said inlet of said fluffer..Iaddend..Iadd.21. A process of treating high consistency fibrous materials, comprising the steps of   simultaneously feeding a high consistency fibrous material having a consistency of 20% to 60% and a mixture of a carrier gas and a reactant consisting essentially of ozone to a fluffer, said fluffer having a stationary grinding plate with said inlet extending through the center thereof, and a rotating grinding plate opposing said stationary grinding plate, said feeding step being in a coaxial direction with respect to an axis of rotation of said rotating grinding plate,   passing said fibrous material, ozone and carrier gas together through a comminuting and reaction zone between said grinding plates in a substantially radial direction to an outlet of said comminuting and reaction zone, and fluffing and reacting said fibrous material while in continuous contact with said ozone,   passing said fluffed fibrous material, unreacted ozone and carrier gas to a second reaction zone for further reaction,   separating unreacted ozone from said second reaction zone and recycling said separated unreacted ozone to said fluffer, and   discharging said fibrous material from said second reaction zone..Iaddend..Iadd.22. The process of claim 21, comprising   cooling said unreacted ozone to about 20° C. to 40° C. before   
     
     
        introducing to said fluffer..Iaddend..Iadd.23.  The process of claim 21, wherein a portion of said separated unreacted ozone from said second reaction zone is recycled to said inlet of said fluffer..Iaddend..Iadd.24. The process of claim 21, wherein said grinding plates are disposed to receive said fibrous material and ozone, and said process comprises feeding said fibrous material and ozone downwardly into said fluffer..Iaddend..Iadd.25. The process of claim 21, comprising cooling said separated unreacted ozone from said second reaction zone prior to said recycling step, wherein a first portion of said cooled separated unreacted ozone is recycled to a lower portion of said fluffer to cool said rotating grinding plate, and wherein a second portion of said cooled separated unreacted ozone is recycled to said inlet to mix with and cool said fibrous material..Iaddend..Iadd.26. The process of claim 21, comprising   cooling said separated unreacted ozone from said second reaction zone prior to recycling to said fluffer, and   contacting said cooled separated unreacted ozone with said fibrous material to cool said fibrous material prior to feeding said fibrous material to said fluffer..Iaddend.