Digester additive formulations and use thereof for pulp production

Abstract

A digester additive formulation includes a combination of phenyl tetracarboxylic acid or a derivative or salt thereof, and a macromolecule polymer. The digester additive formulation is as an additive for a kraft process for production of pulp from raw materials, such as wood chips. When used in the kraft pulping process, the digester additive formulation improves viscosity of the resulting pulp and increases pulp yield.

What is claimed is: 
     
         1 . A digester additive formulation for a kraft process for producing wood pulp, the digester additive formulation comprising phenyl tetracarboxylic acid or a derivative or salt thereof, and a macromolecule polymer, wherein the phenyl tetracarboxylic acid is of the structure shown in Formula I: 
       
         
           
           
               
               
           
         
         and the macromolecule polymer comprises a structure selected from the group of structures of Formulae II-V: 
       
       
         
           
           
               
               
           
         
       
       wherein R is selected from an alkyl group, an aryl group, an alkenyl group, or an alkynyl group; 
       
         
           
           
               
               
           
         
       
       wherein the moiety [P,S] denotes either a phosphorus or a sulfur, but not both, the moiety R is selected from hydrogen, a hydrocarbyl group, or an aryl group, and each X is independently hydrogen or a metal cation; and 
       
         
           
           
               
               
           
         
       
       wherein each of R 1  and R 2  is independently hydrogen, a hydrocarbyl group, or an aryl group. 
     
     
         2 . The digester additive formulation of  claim 1 , wherein the macromolecule polymer comprises the structure of Formula II and is a block copolymer of polyethylene oxide and polypropylene oxide (an EO/PO block copolymer). 
     
     
         3 . The digester additive formulation of  claim 2 , wherein the value of each x in Formula II is independently from 5 to 110, the value of y in Formula II is from 10 to 40, and the sum of the values of both x's is from 10 to 115. 
     
     
         4 . The digester additive formulation of  claim 2 , wherein the value of each x in Formula II is independently from 10 to 20, and the value of y in Formula II is from 25 to 35. 
     
     
         5 . The digester additive formulation of  claim 1 , wherein the macromolecule polymer comprises the structure of Formula III. 
     
     
         6 . The digester additive formulation of  claim 5 , wherein R contains from 1 to 16 carbon atoms. 
     
     
         7 . The digester additive formulation of  claim 5 , wherein the macromolecule comprises a monoester of a fatty acid esterified from an EO/PO block copolymer. 
     
     
         8 . The digester additive formulation of  claim 7 , wherein the value of each x in Formula III is independently from 5 to 110 and the value of y in Formula III is from 10 to 40. 
     
     
         9 . The digester additive formulation of  claim 7 , wherein the value of each x in Formula III is independently from 10 to 20 and the value of y in Formula III is from 25 to 35. 
     
     
         10 . The digester additive formulation of  claim 1 , wherein the macromolecule polymer comprises the structure of Formula IV. 
     
     
         11 . The digester additive formulation of  claim 10 , wherein the macromolecule polymer comprises a linear alkyl ethoxylated phosphate or a linear alkyl ethoxylated sulfate. 
     
     
         12 . The digester additive formulation of  claim 10 , wherein each X is hydrogen. 
     
     
         13 . The digester additive formulation of  claim 10 , wherein R is hydrogen. 
     
     
         14 . The digester additive formulation of  claim 10 , wherein the value of x in Formula IV is from 5 to 110 and the value of y in Formula IV is from 10 to 40. 
     
     
         15 . The digester additive formulation of  claim 10 , wherein the value of x in Formula IV is from 10 to 20 and the value of y in Formula IV is from 25 to 35. 
     
     
         16 . The digester additive formulation of  claim 1 , wherein the macromolecule polymer comprises the structure of Formula V. 
     
     
         17 . The digester additive formulation of  claim 16 , wherein the macromolecule polymer comprises a linear alkyl ethoxylated alcohol. 
     
     
         18 . The digester additive formulation of  claim 16 , wherein each of R 1  and R 2  is hydrogen. 
     
     
         19 . The digester additive formulation of  claim 16 , wherein R 1  is different than R 2 . 
     
     
         20 . The digester additive formulation of  claim 16 , wherein R 1  and R 2  are the same. 
     
     
         21 . The digester additive formulation of  claim 16 , wherein the value of x in Formula V is from 5 to 110 and the value of y in Formula V is from 10 to 40. 
     
     
         22 . The digester additive formulation of  claim 16 , wherein the value of x in Formula V is from 10 to 20 and the value of y in Formula V is from 25 to 35. 
     
     
         23 . The digester additive formulation of  claim 1 , wherein the phenyl tetracarboxylic acid or a derivative or salt thereof, is a derivative of phenyl tetracarboxylic acid. 
     
     
         24 . The digester additive formulation of  claim 23 , wherein the derivative of phenyl tetracarboxylic carboxylic acid is selected from the group consisting of alkyl-substituted phenyl monocarboxylic acids, alkyl-substituted phenyl dicarboxylic acids, alkyl-substituted phenyl tricarboxylic acids, and alkyl-substituted phenyl tetracarboxylic acids. 
     
     
         25 . The digester additive formulation of  claim 1 , wherein the phenyl tetracarboxylic acid or a derivative or salt thereof, is a salt of phenyl tetracarboxylic acid. 
     
     
         26 . A mixture comprising oven dried wood chips for use in a kraft process for making wood pulp, and the digester additive formulation of  claim 1 , wherein the digester additive formulation is present in the mixture in an amount of from 0.001% by weight to 8% by weight, based on the weight of the oven-dried wood chips. 
     
     
         27 . A wood pulp mixture for use in a kraft process for making wood pulp, the mixture comprising wood chips, white liquor, dilution water, and the digester additive formulation of  claim 1 . 
     
     
         28 . The wood pulp mixture of  claim 27 , wherein the digester additive formulation is present in the mixture in an amount of from 0.001% by weight to 8% by weight, based on a dry weight of the wood chips. 
     
     
         29 . A method comprising:
 mixing together wood chips, white liquor, dilution water, and the digester additive formulation of  claim 1 , to form a wood pulp mixture.   
     
     
         30 . The method of  claim 29 , wherein the phenyl tetracarboxylic acid or a derivative or salt thereof, and a macromolecule polymer, are first mixed together to form the digester additive formulation, before the digester additive formulation is mixed with the wood chips, the white liquor, and the dilution water. 
     
     
         31 . The method of  claim 29 , comprising first mixing together the wood chips, the white liquor, and the dilution water, to form a precursor mixture, and then adding separately the phenyl tetracarboxylic acid or a derivative or salt thereof, and a macromolecule polymer, so that the digester additive formulation is formed in-situ, in the precursor mixture, to form the wood pulp mixture. 
     
     
         32 . The method of  claim 29 , further comprising forming a wood pulp from the wood pulp mixture, and forming a paper from the wood pulp, according to a kraft process. 
     
     
         33 . The method of  claim 32 , wherein the method improves pulp viscosity of the wood pulp, improves yield of the wood pulp, and reduces rejects in forming the wood pulp, when compared with the same method but carried out without the use of the digester additive formulation.