Method And System For Producing Market Pulp And Products Thereof

Abstract

Methods and systems are provided for producing market pulp which include treatment of pulp before pulp drying. An anionically charged compound and enzyme are used to treat pulp before pulp drying to improve pulp dewatering performance and efficiency in the production of market pulp. Market pulp products containing the treatment compounds are also described.

What is claimed is: 
     
         1 . A method for producing market pulp, comprising:
 forming cellulosic particulates into pulp;   adding at least one anionically charged compound and at least one enzyme to said pulp to provide treated pulp;   mechanically dewatering said treated pulp to provide mechanically dewatered pulp; and   thermally drying said mechanically dewatered pulp to form market pulp.   
     
     
         2 . The method of  claim 1 , wherein at least part of said adding of said enzyme to said pulp occurs prior to said adding of said anionically charged compound to said pulp. 
     
     
         3 . The method of  claim 1 , wherein about 80% to 100% by weight of said adding of said enzyme to said pulp occurs prior to said adding of said anionically charged compound to said pulp. 
     
     
         4 . The method of  claim 1 , wherein the anionically charged compound is an organic anionically charged compound. 
     
     
         5 . The method of  claim 1 , wherein the enzyme is a hydrolytic enzyme. 
     
     
         6 . The method of  claim 1 , further comprising bleaching the pulp after the pulp forming and before the adding of the anionically charged compound and enzyme to said pulp. 
     
     
         7 . A method for producing market pulp, comprising:
 forming cellulosic particulates into pulp;   adding at least one anionic surfactant and at least one enzyme to said pulp to provide treated pulp;   mechanically dewatering said treated pulp to provide mechanically dewatered pulp; and   thermally drying said mechanically dewatered pulp to form market pulp.   
     
     
         8 . The method of  claim 7 , wherein at least part of said adding of said enzyme to said pulp occurs prior to said adding of said anionic surfactant to said pulp. 
     
     
         9 . The method of  claim 7 , wherein about 80% to 100% by weight of said adding of said enzyme to said pulp occurs prior to said adding of said anionic surfactant to said pulp. 
     
     
         10 . The method of  claim 7 , further comprising bleaching the pulp after the pulp forming and before the adding of the anionic surfactant and enzyme to said pulp. 
     
     
         11 . The method of  claim 7 , wherein the anionic surfactant is a sulfate surfactant, a sulfonate surfactant, a sulfosuccinate surfactant, or any combinations thereof. 
     
     
         12 . The method of  claim 7 , wherein the anionic surfactant is an alcohol sulfate, an alcohol alkoxy sulfate, a sulfonate, a dialkyl sulfosuccinate, an sulfosuccinic acid ester with an ethoxylated alcohol, or a soluble or dispersible salt thereof, or any combinations thereof. 
     
     
         13 . The method of  claim 7 , wherein the enzyme is cellulase, hemicellulase, pectinase, cellobiase, xylanase, mannanase, β-glucanase, carboxymethylcellulase, amylase, glucosidase, galactosidase, laccase, or any combinations thereof. 
     
     
         14 . The method of  claim 7 , wherein said forming provides kraft pulp, sulfite pulp, fluff pulp, dissolving pulp, bleached chemothermomechanical pulp, or any combinations thereof. 
     
     
         15 . The method of  claim 7 , further comprising bleaching the pulp after the pulp forming and before the adding of the anionic surfactant and enzyme to said pulp. 
     
     
         16 . The method of  claim 7 , wherein said mechanically dewatering comprises screening and pressing of the pulp, wherein drained white water from said screening is combined with fresh pulp and pumped with a fan pump to a head box for the screening, wherein said enzyme is fed into the combined fresh pulp and white water before entering the fan pump, and said anionic surfactant is fed into said combined fresh pulp and white water after exiting said fan pump and before reaching the headbox. 
     
     
         17 . The method of  claim 7 , wherein the anionic surfactant and enzyme are added to the pulp in a ratio of from about 10,000:1 to about 1:10. 
     
     
         18 . The method of  claim 7 , wherein the anionic surfactant is added to the pulp in an amount of from about 0.1 lb./ton dry fiber to about 10 lb./ton dry fiber, and the enzyme is added to the pulp in an amount of from about 0.001 lb./ton dry fiber to about 2 lb./ton dry fiber. 
     
     
         19 . The method of  claim 7 , further comprising unitizing said market pulp to form unitized market pulp. 
     
     
         20 . The method of  claim 7 , wherein the cellulosic particulates are hardwood chips, softwood chips, recycled paper fiber, or any combinations thereof. 
     
     
         21 . The method of  claim 7 , wherein the combination of treating the pulp with the at least one anionic surfactant and at least one enzyme before dewatering in the production of market pulp is effective to provide at least one of the following:
 (i) increased pulp free drainage (g/90 sec) to a value which is at least 7.5% times greater than free drainage value obtained without any treatment in the pulp;   (ii) increased pulp free drainage to a value which is at least about 3% greater than free drainage value obtained with using the anionic surfactant individually in the pulp (without the enzyme);   (iii) increased pulp free drainage to a value which is at least about 10% greater than a free drainage value calculated as a sum of the free drainage increases obtained from using the anionic surfactant and enzyme separately and individually in the pulp; and   (iv) reducing pulp water retention value (WRV) to a value which is at least about 10% less than WRV obtained with using the anionic surfactant individually in the pulp (without the enzyme).   
     
     
         22 . The method of  claim 7 , wherein the treating is effective for increasing obtained free drainage to a value which is at least five times greater than free drainage value obtained without any treatment of the pulp. 
     
     
         23 . The method of  claim 7 , wherein the treating is effective for increasing obtained free drainage to a value which is from about 60% to about 200% greater than free drainage value obtained with using the anionic surfactant individually in the pulp. 
     
     
         24 . A market pulp made by the method of  claim 1  containing said anionically charged compound and said enzyme. 
     
     
         25 . A market pulp made by the method of  claim 7  containing said anionic surfactant and said enzyme. 
     
     
         26 . A system for producing market pulp comprising:
 a supply of cellulosic particulates;   at least one pulp forming unit for forming pulp from said cellulosic particulates;   at least one feeding device for feeding at least one anionically charged compound to said pulp;   at least one feeding device for feeding at least one enzyme to said pulp to provide treated pulp after addition of both the anionically charged compound and the enzyme;   a mechanical dewatering device for mechanically removing water from said treated pulp to provide mechanically dewatered pulp; and   a thermal drying device for thermally removing water from said mechanically dewatered pulp to provide market pulp.   
     
     
         27 . The system of  claim 26 , wherein said at least one feeding device for feeding anionically charged compound feeds anionic surfactant and said at least one feeding device for feeding enzyme feeds hydrolytic enzyme. 
     
     
         28 . The system of  claim 26 , wherein said pulp forming unit is a digester capable of receiving at least one chemical for digesting the cellulosic particulates. 
     
     
         29 . The system of  claim 26 , wherein said mechanical dewatering device comprises screen and press sections, wherein drained white water from the screen section is combinable with fresh pulp and pumpable with a fan pump to a head box of the mechanical dewatering device, wherein said at least one feeding device for said enzyme is capable of feeding said enzyme into the combined fresh pulp and white water before entering said fan pump, and said at least one feeding device for said anionically charged compound is capable of feeding said anionically charged compound into said combined fresh pulp and white water after exiting said fan pump and before reaching the headbox. 
     
     
         30 . The system of  claim 26 , further comprising a bleaching unit for bleaching the pulp after the pulp forming unit and before the adding of the anionically charged compound and enzyme to said pulp with said feeding devices. 
     
     
         31 . The system of  claim 26 , wherein the first and second feeding devices being capable of introducing respective first and second amounts of the anionically charged compound and enzyme to pulp drawn from the pulp forming unit to provide at least one of the following:
 (i) increased pulp free drainage (g/90 sec) to a value which is at least 7.5% times greater than free drainage value obtained without any treatment in the pulp;   (ii) increased pulp free drainage to a value which is at least about 3% greater than free drainage value obtained with using the anionically charged compound individually in the pulp (without the enzyme);   (iii) increased pulp free drainage to a value which is at least about 10% greater than a free drainage value calculated as a sum of the free drainage increases obtained from using the anionically charged compound and enzyme separately and individually in the pulp; and   (iv) reducing pulp water retention value (WRV) to a value which is at least about 10% less than WRV obtained with using the anionically charged compound individually in the pulp (without the enzyme).