Method for producing fibrous material

Abstract

A method for producing fibrous material from softwood, hardwood, or annual plants, including preparing a solution of chemicals having one of: more than 5% of chemicals for softwood, more than 3.5% of chemicals for hardwood, or more than 2.5% of chemicals for annual plants. The method includes: mixing the solution of chemicals with the lignocellulosic material in a predetermined liquor ratio; heating the solution of chemicals and the lignocellulosic material to a temperature above room temperature; and, after the heating, performing one of: removing a free-flowing portion of the solution of chemicals and digesting the lignocellulosic material in a vapor phase, or digesting the lignocellulosic material in a liquid phase and separating the free-flowing portion of the solution of chemicals and the lignocellulosic material. The produced fibrous material has a lignin content of at least 15% for softwood, at least 12% for hardwood, and at least 10% for annual plants.

1 - 19 . (canceled) 
   
   
       20 . A method for producing fibrous material from lignocellulosic material, the lignocellulosic material comprising one of softwood, hardwood, and annual plants, the method comprising:
 preparing a solution of chemicals comprising one of: more than 5% of chemicals for softwood, more than 3.5% of chemicals for hardwood, or more than 2.5% of chemicals for annual plants, wherein percent of chemicals is calculated as NaOH and is based on an oven-dry amount of the lignocellulosic material,   mixing the solution of chemicals with the lignocellulosic material in a predetermined liquor ratio;   heating the solution of chemicals and the lignocellulosic material to a temperature above room temperature; and   after the heating, performing a digesting comprising one of: removing a free-flowing portion of the solution of chemicals and digesting the lignocellulosic material in a vapor phase, or digesting the lignocellulosic material in a liquid phase and separating the free-flowing portion of the solution of chemicals and the lignocellulosic material,   wherein the produced fibrous material has a lignin content of at least 15%, based on oven-dry fibrous material, when the lignocellulosic material comprises softwood, a lignin content of at least 12%, based on oven-dry fibrous material, when the lignocellulosic material comprises hardwood, and a lignin content of at least 10%, based on oven-dry fibrous material, when the lignocellulosic material comprises annual plants.   
   
   
       21 . The method of  claim 20 , wherein the lignocellulosic material comprises softwood and the produced fibrous material has a lignin content of at least 18%. 
   
   
       22 . The method of  claim 20 , wherein the lignocellulosic material comprises softwood and the produced fibrous material has a lignin content of at least 21%. 
   
   
       23 . The method of  claim 20 , wherein the lignocellulosic material comprises hardwood and the produced fibrous material has a lignin content of at least 14%. 
   
   
       24 . The method of  claim 20 , wherein the lignocellulosic material comprises hardwood and the produced fibrous material has a lignin content of at least 16%. 
   
   
       25 . The method of  claim 20 , wherein the lignocellulosic material comprises annual plants and the produced fibrous material has a lignin content of at least 12%. 
   
   
       26 . The method of  claim 20 , wherein the solution of chemicals comprises a quinine component. 
   
   
       27 . The method of  claim 20 , wherein the lignocellulosic material comprises softwood and not more than 15% of the chemicals are used for the digesting. 
   
   
       28 . The method of  claim 20 , wherein the lignocellulosic material comprises softwood and between 9% and 11% of the chemicals are used for the digesting. 
   
   
       29 . The method of  claim 20 , wherein the lignocellulosic material comprises hardwood and not more than 10% of the chemicals are used for the digesting. 
   
   
       30 . The method of  claim 20 , wherein the lignocellulosic material comprises hardwood and between 4% and 10% of the chemicals are used for the digesting. 
   
   
       31 . The method of  claim 20 , wherein the lignocellulosic material comprises hardwood and between 6% and 8% of the chemicals are used for the digesting. 
   
   
       32 . The method of  claim 20 , wherein the lignocellulosic material comprises annual plants and not more than 10% of the chemicals are used for the digesting. 
   
   
       33 . The method of  claim 20 , wherein the lignocellulosic material comprises softwood and between 3% and 10% of the chemicals are used for the digesting. 
   
   
       34 . The method of  claim 20 , wherein the solution of chemicals comprises at least one of sulfites and sulfides. 
   
   
       35 . The method of  claim 34 , wherein the solution of chemicals comprises at least one of an acidic and an alkaline component. 
   
   
       36 . The method of  claim 34 , wherein the solution of chemicals comprises at least one of an acid, sulfur dioxide, sodium hydroxide, and a carbonate. 
   
   
       37 . The method of  claim 20 , wherein the digesting uses an alkaline component and an acidic component, the acidic component comprises SO 2 , and a ratio of the alkaline component to the SO 2  is in a range from 4:1 to 1.6:1. 
   
   
       38 . The method of  claim 20 , wherein the digesting uses an alkaline component and an acidic component, the acidic component comprises SO 2 , and a ratio of the alkaline component to the SO 2  is in a range from 2:1 to 1.6:1. 
   
   
       39 . The method of  claim 20 , wherein the solution of chemicals has a pH between 6 and 11. 
   
   
       40 . The method of  claim 20 , wherein the solution of chemicals has a pH between 7 and 11. 
   
   
       41 . The method of  claim 20 , wherein the solution of chemicals has a pH between 7.5 and 10. 
   
   
       42 . The method of  claim 20 , wherein the predetermined liquor ratio is a ratio of the lignocellulosic material to the solution of chemicals and is between 1:1.5 and 1:6. 
   
   
       43 . The method of  claim 42 , wherein the predetermined liquor ratio is between 1:3 and 1:5. 
   
   
       44 . The method of  claim 20 , wherein the heating comprises heating the solution of chemicals and the lignocellulosic material to a temperature less than or equal to 120° C. 
   
   
       45 . The method of  claim 20 , wherein the heating comprises heating the solution of chemicals and the lignocellulosic material to a temperature less than or equal to 110° C. 
   
   
       46 . The method of  claim 20 , wherein the heating lasts for less than or equal to 90 minutes. 
   
   
       47 . The method of  claim 20 , wherein the heating lasts for less than or equal to 60 minutes. 
   
   
       48 . The method of  claim 20 , wherein the heating lasts for less than or equal to 30 minutes. 
   
   
       49 . The method of  claim 20 , wherein the heating lasts for less than or equal to 10 minutes. 
   
   
       50 . The method of  claim 20 , wherein the digesting is carried out at a temperature between 120° C. and 190° C. 
   
   
       51 . The method of  claim 20 , wherein the digesting is carried out at a temperature between 150° C. and 180° C. 
   
   
       52 . The method of  claim 20 , wherein the digesting is carried out at a temperature between 160° C. and 170° C. 
   
   
       53 . The method of  claim 20 , wherein the digesting lasts for less than or equal to 180 minutes. 
   
   
       54 . The method of  claim 20 , wherein the digesting lasts for less than or equal to 90 minutes. 
   
   
       55 . The method of  claim 20 , wherein the digesting lasts for less than or equal to 60 minutes. 
   
   
       56 . The method of  claim 20 , wherein the digesting lasts for less than or equal to 30 minutes. 
   
   
       57 . The method of  claim 20 , wherein the digesting lasts for less than or equal to 2 minutes. 
   
   
       58 . The method of  claim 20 , wherein less than or equal to 80% of the chemicals present at a beginning of the digesting are consumed during the digesting. 
   
   
       59 . The method of  claim 20 , wherein less than or equal to 60% of the chemicals present at a beginning of the digesting are consumed during the digesting. 
   
   
       60 . The method of  claim 20 , wherein less than or equal to 40% of the chemicals present at a beginning of the digesting are consumed during the digesting. 
   
   
       61 . The method of  claim 20 , further comprising:
 determining a composition of the free-flowing portion of the solution of chemicals; and   adjusting the composition of the free-flowing portion of the solution of chemicals for further use in producing other fibrous materials.   
   
   
       62 . The method of  claim 20 , further comprising:
 washing the produced fibrous material to release another portion of the solution of chemicals; and   using the other portion of the solution of chemicals in another process.   
   
   
       63 . The method of  claim 62  further comprising beating the digested lignocellulosic material before the washing.