Method for producing corn stalk pulp and paper products from corn stalk pulp

Abstract

A new method for making pulp out of agricultural residue includes harvesting certain portion of plant stalk. The harvested plant stalk is bailed, transported and stored. At the mill, the plant stalk is chopped and goes through pulping process. The pulp is used to make varieties of papers with or without blending other wood based pulp.

What is claimed is:  
     
         1 . A method for producing pulp from agricultural residues, comprising: 
 harvesting a portion of a cornstalk plant, wherein the harvesting includes removing a portion of the cornstalk below about at least one of a ear on the cornstalk plant;    drying the cornstalk portions;    chopping the cornstalk portions;    washing of the chopped cornstalk portions;    compacting the washed cornstalk portions in a screw feeder to remove water;    extracting pulp from the compacted cornstalk portions with an alkaline pulping solution at predetermined conditions;    fiberizing the pulp;    washing the pulp; and    treating of the fiberized and washed pulp with a bleaching solution, wherein the bleaching solution removes residual lignin and color for increasing the brightness to greater than about 70% ISO.    
     
     
         2 . The method of  claim 1 , wherein batch processes of at least one of trembling, stationary digester, and super batch digester is utilized.  
     
     
         3 . The method of  claim 1 , wherein continuous processing of at least one of Pandia digester and Kymer digester are utilized.  
     
     
         4 . The method of  claim 1 , wherein the cooking of cornstalk in the alkaline solution is done at a temperature ranging from about 120 to 160° C. for about 30 min to 120 min.  
     
     
         5 . The method of  claim 4 , wherein the alkaline solution comprises an alkaline hydroxide solution including at least one of sodium hydroxide, potassium hydroxide, ammonium hydroxide, and calcium hydroxide.  
     
     
         6 . The method of  claim 4 , wherein the alkaline solution further includes at least one of sodium carbonate and sodium bicarbonate.  
     
     
         7 . The method of  claim 6 , wherein the alkaline solution further includes sodium hydroxide.  
     
     
         8 . The method of  claim 7 , wherein the alkaline solution further includes anthraquinone.  
     
     
         9 . The method of  claim 7 , wherein the sodium hydroxide has a concentration in the range from about 2% to 18% active alkali and the anthraquinone has a concentration in the range from about 0.0% to 0.5%.  
     
     
         10 . The method of  claim 7 , wherein a pretreatment step involving compacted cornstalk material with cellulose protecting agents such as MgCl 2 , CaCO 3  at a temperature between about 60 to about 100° C. for about 30 to about 60 minutes might be used in order to protect the hemicellulose during alkaline digestion of cornstalk.  
     
     
         11 . The method of  claim 1 , wherein the bleaching solution comprises chlorine dioxide.  
     
     
         12 . The method of  claim 1 , wherein the treating of the fiberized and washed pulp with a bleaching solution is performed at a temperature ranging from about 50 to 100° C. for about 30 to 120 minutes.  
     
     
         13 . The method of  claim 1 , wherein the alkaline pulping solution includes a concentration ranging from about 1% to 3% sodium hydroxide.  
     
     
         14 . The method of  claim 1 , wherein a chlorine dioxide-alkaline extraction-chlorine dioxide (DED) bleaching sequence raises the pulp brightness to about 80-85% ISO.  
     
     
         15 . The method of  claim 14 , wherein after the DED sequence one of a hydrogen peroxide bleaching solution (P), ozone solution (Z) and oxygen solution (O) is used for raising the pulp brightness to about 86 to 95% ISO.  
     
     
         16 . The method of  claim 15 , wherein the chlorine dioxide bleaching solution comprises a dosage of chlorine dioxide equivalent to pulps' kappa factor ranging from about 0.01 to 0.5.  
     
     
         17 . The method of  claim 16 , wherein the hydrogen peroxide bleaching solution comprises: 
 hydrogen peroxide of about 1 to 3% of o. d. pulp weight;sodium hydroxide of about 1 to 3% of o. d. pulp weight;    sodium silicate of about 1 to 3% of o. d. pulp weight;    magnesium sulfate of about 0.02 to 0.06% of o. d. pulp weight; and    trace amounts of chealant    
     
     
         18 . The method of  claim 17 , further comprising: 
 a bleaching stage to improve the brightness of cornstalk pulp,    wherein the bleaching stage uses bleaching reagent, such as ozone of about 0.05 to 5% (of o. d. pulp weight) and oxygen of about 0.1 to 2% (of o. d. pulp weight).    
     
     
         19 . A method for making paper out of pulp from agricultural residue, comprising: 
 refining pulp from agricultural residue;    blending the pulp from agricultural residue;    cleaning;    screening; and    rolling in the paper machine,    wherein the pulp from agricultural residue is cornstalk pulp.    
     
     
         20 . The method of  claim 19 , wherein the cornstalk pulp has freeness level of at least 250 ml or greater.  
     
     
         21 . The method of  claim 19 , wherein the cornstalk pulp has a kappa number in a range of about 7 to 80.  
     
     
         22 . The method of  claim 19 , wherein the cornstalk pulp has a kappa number in a range of about 2 to 7.  
     
     
         23 . The method of  claim 19 , wherein the cornstalk pulp has a kappa number below about 2.  
     
     
         24 . The method of  claim 19 , wherein cornstalk pulp can be used without refining and/or with refining to 250-500 ml CSF before combining with wood pulp to provide the specific properties that can meet the end-uses of paper products.  
     
     
         25 . The method of  claim 19 , wherein cornstalk pulp can be fractionated into long fiber and short fiber fractions and reblended depending on the properties of end-uses to maximize the performance of cornstalk pulp.  
     
     
         26 . The method of  claim 19 , wherein writing and printing paper, photocopy, specialty papers, and envelope papers can be produced from bleached cornstalk pulp by the blending with one or more pulp and/or additives from a group comprising: 
 bleached softwood chemical pulp;    bleached hardwood chemical pulp: 0-20%;    filler (precipitated or grounded calcium carbonate, clay, kaolin, talc, titanium dioxide, etc.): 0-30%;    dry strength chemicals (starch or other polymeric materials): 0-4%;    sizing agent (rosin emulsion, AKD, ASA or others): 0.05-5%; and    cationic and/or anionic polymeric retention aids (starch, poly acryl amide, poly ethylene imine, colloidal silica, bentonite, organic micro-particles, etc): 0-5%.    
     
     
         27 . The method, of  claim 19 , wherein top white liner can be produced from bleached cornstalk pulp by blending with one or more additives from a group comprising: 
 bleached softwood chemical pulp: 0-30%;    bleached hardwood chemical pulp: 0-30%;    filler (precipitated or ground calcium carbonate, clay or kaolin): 0-20%;    dry strength agent (starch or other polymeric materials): 0-4%;    sizing agent (rosin emulsion, AKD, ASA or others): 0.05-2%; and    retention aid (starch, poly acryl amide, poly ethylene imine, colloidal silica, bentonite, organic micro-particles, etc): 0-5%.    
     
     
         28 . The method of  claim 19 , wherein carton package for milk, juice, and other beverages can be produced from bleached cornstalk pulp by blending with one or more additives from a group comprising: 
 bleached softwood chemical pulp: 0-20%;    sizing agents (rosin emulsion, AKD, ASA or others): 0.01-5%; and    retention aid (starch, poly acryl amide, poly ethylene imine, colloidal silica, bentonite, organic micro-particles, etc): 0-5.5%.    
     
     
         29 . The method of  claim 19 , wherein linerboard can be produced from unbleached cornstalk chemical or semi-chemical pulp without or with unbleached softwood chemical or semi-chemical pulp.  
     
     
         30 . The method of  claim 19 , wherein corrugating medium can be produced from high yield cornstalk pulp mixed with high yield hardwood pulp.  
     
     
         31 . The method of  claim 19 , wherein tissue papers, wet strength papers, and industrial papers can be produced from bleached cornstalk pulp by blending with one or more additives from a group comprising: 
 bleached softwood chemical pulp: 0-30%;    bleached hardwood chemical pulp: 0-20%;    sizing agents (rosin emulsion, AKD, ASA or others): 0.01-5%; and    retention aid (starch, poly acryl amide, poly ethylene imine, colloidal silica, bentonite, organic micro-particles, etc): 0-5.5%.    
     
     
         32 . The method of  claim 19 , wherein photocopy papers, specialty papers, and envelope papers can be produced from bleached cornstalk pulp by blending with one or more additives from a group comprising: 
 bleached softwood chemical pulp: 0-30%;    bleached hardwood chemical pulp: 0-20%;    filler (precipitated or ground calcium carbonate, clay or kaolin): 0-40%;    dry strength agent (starch or other polymeric materials): 0-5%;    sizing agents (rosin emulsion, AKD, ASA or others): 0.01-5%; and    retention aid (starch, poly acryl amide, poly ethylene imine, colloidal silica, bentonite, organic micro-particles, etc): 0-5.5%.