Method for Controlling a Pulping Process

Abstract

Please delete the Abstract as originally filed and substitute therefore the attached substitute Abstract which is submitted in both marked-up and clean copy versions.

1 - 6 . (canceled) 
   
   
       7 . A method for controlling a pulp digester process for cooking a column of chips comprising:
 (a) measuring the size and shape of said chips fed into said pulp digester to provide measured values therefore;   (b) calculating the sphericity factor and the equivalent diameter of said chips based on said measured values;   (c) determining the bulk density of said chip column from said calculated values of said sphericity factor and said equivalent diameter of said chips; and   (d) using a mathematical model to calculate the porosity of said chip column and the pressure loss of liquid flowing through said chip column in the various stages of said cooking process.   
   
   
       8 . The method according to  claim 7  including using a mathematical model to calculate the age factor of said cooking process. 
   
   
       9 . The method according to  claim 7  for controlling a continuous pulp digester including a chip meter and a plurality of cooking zones including;
 (e) determining the output of said pulp digester based on the size and speed of rotation of said chip meter and the bulk density of said chips;   (f) determining a target kappa number and target values for alkali dosage and H-factors required for said output;   (g) calculating the porosity of said chip column in each of said cooking zones of said pulp digester;   (h) calculating the residence time of said chip column in each of said cooking zones in said pulp digester;   (i) calculating the H-factor in each of said cooking zones;   (j) determining the kappa number in each of said cooking zones;   (k) repeating said steps (g) through (j) as necessary;   (l) calculating the pressure loss of liquid flowing through said chip column in each of said cooking zones;   (m) adjusting the set value for said chip meter based on said determined output;   (n) adjusting the set value for said alkali dosage and temperature in each of said cooking zones based on said calculated H-factor and kappa numbers; and   (o) adjusting the set values for the circulation flow rates in said pulp digester in each of said cooking zones based on said calculated pressure losses.   
   
   
       10 . The method according to  claim 7  for controlling a batch digester including:
 (e) calculating the amount of said chips fed into said pulp digester based on the bulk density and volume of said pulp digester including a plurality of cooling stages;   (f) determining a target kappa number;   (g) determining target values for alkali dosage and H-factor;   (h) calculating said H-factor in each of said cooking stages;   (i) calculating the kappa number in each of said cooking stages;   (j) calculating the porosity of said chip column in each of said cooking stages;   (k) calculating the pressure loss of a liquid flowing through said chip column in each of said cooking stages;   (l) adjusting the set values for the temperature and residence time based on said H-factor and said kappa number; and   (m) adjusting the set values for liquid circulation flow rates in each of said cooking stages.