Method of controlling recycled fibre line, and recycled fibre line

Abstract

Measuring devices measure at least one characteristic of the fibres of recycled fibre pulp and at least one characteristic of ink, and the measuring devices feed the measurement results to controllers of a pulping subprocess and a dispersing subprocess, the controllers performing multivariable-based predictive calculation and optimization of control functions. The controllers of the pulping sub-process and the dispersing subprocess generate control variables on the basis of the measurement results for mechanical and chemical processing of the recycled fibre pulp to be performed in the pulping subprocess and the dispersing subprocess.

1 . A method of controlling a recycled fibre line comprising a pulping subprocess and a dispersing subprocess, and wherein recycled fibre pulp is processed, wherein
 measuring at least one characteristic of ink and at least one of the following: number of fibre bundles, number of fibres attached to each other from the recycled fibre pulp of the recycled fibre line, and feeding measurement results to a controller of the pulping subprocess and to a controller of the dispersing subprocess, which perform multivariable-based predictive calculation and optimization of control functions;   generating, on the basis of the measurement results in the controller of the pulping subprocess, at least one control variable for mechanic processing of the recycled fibre pulp performed in the pulping subprocess and at least one control variable for chemical processing of the recycled fibre pulp performed in the pulping subprocess, and   generating, on the basis of the measurement results in the controller of the dispersing subprocess, at least one control variable for mechanical processing of recycled fibre pulp performed in the dispersing subprocess and at least one control variable for chemical processing of recycled fibre pulp performed in the dispersing subprocess.   
   
   
       2 . A method as claimed in  claim 1 , wherein measuring at least one characteristic of the fibres of the recycled fibre pulp and at least characteristic of the ink between the pulping subprocess and the dispersing subprocess, and feeding measurement results to the controller of the pulping subprocess; and
 measuring at least one characteristic of the fibres of the recycled fibre pulp and at least one characteristic of the ink after the dispersing subprocess, and feeding measurement results to the controller of the dispersing subprocess.   
   
   
       3 . A method as claimed in  claim 1 , wherein generating a characteristic of the recycled fibre pulp by means of a model from the measurement results by measuring at least one of the following: fibre length, amount of fibrous fine material, drainability. 
   
   
       4 . A method as claimed in  claim 1 , wherein generating a characteristic of the recycled fibre pulp by means of a model from the measurement results by measuring at least one of the following: number of fibre bundles, number of fibres attached to each other. 
   
   
       5 . A method as claimed in  claim 1 , wherein generating a characteristic of the ink by means of a model by measuring at least one of the following: amount of ink attached to fibres, amount of free ink, brightness of the recycled fibre pulp, amount of ink removed in washing, amount of ink not removed in washing, size distribution of free ink particles. 
   
   
       6 . A method as claimed in  claim 1 , wherein determining a fibre parameter descriptive of the detachment of fibres from each other in the controller of the pulping subprocess by means of at least one measurement and using the parameter in the generation of at least one control variable; and determining an ink parameter descriptive of the detachment of ink from fibres in the controller of the pulping subprocess by means of at least one measurement and using the parameter in the generation of at least one control variable. 
   
   
       7 . A method as claimed in  claim 1 , wherein determining a fibre parameter descriptive of the detachment of fibres from each other in the controller of the dispersing subprocess by means of at least one measurement and using the parameter in the generation of at least one control variable; and determining an ink parameter descriptive of the detachment of ink from fibres in the controller % of the dispersing subprocess by means of at least one measurement and using the parameter in the generation of at least one control variable. 
   
   
       8 . A method as claimed in  claim 1 , wherein determining at least one chemical parameter in the controller of the pulping subprocess for controlling the dosage of chemicals into the recycled fibre process; end determining at least of one mechanical parameter in the controller of the pulping subprocess for controlling the mechanical processing in the recycled fibre process. 
   
   
       9 . A method as claimed in  claim 1 , wherein determining at least one chemical parameter in the controller of the dispersing subprocess for controlling the dosage of chemicals into the recycled fibre process; and determining at least of one mechanical parameter in the controller of the dispersing subprocess for controlling the mechanical processing in the recycled fibre process. 
   
   
       10 . A method as claimed in  claim 1 , characterized by wherein controlling a continuous pulper of the pulping subprocess with control variables. 
   
   
       11 . A method as claimed in  claim 1 , wherein controlling a batch pulper of the pulping subprocess with control variables. 
   
   
       12 . A method as claimed in  claim 1 , wherein generating a control variable by means of the measurement results in the controller of the pulping subprocess for controlling the consistency of the pulping subprocess. 
   
   
       13 . A method as claimed in  claim 1 , wherein generating a control variable by means of the measurement results in the controller of the pulping subprocess for adjusting the speed of rotation of a pulper. 
   
   
       14 . A method as claimed in  claim 1 , wherein generating a control variable for adjusting pulping time in the controller of the pulping subprocess by means of the measurement results. 
   
   
       15 . A method as claimed in  claim 1 , wherein generating a control variable by means of the measurement results in the controller of the pulping subprocess for adjusting fibre swelling. 
   
   
       16 . A method as claimed in  claim 1 , wherein generating a control variable by means of the measurement results in the controller of the dispersing subprocess for adjusting fibre swelling. 
   
   
       17 . A method as claimed in  claim 1 , wherein generating a control variable by means of the measurement results in the controller of the pulping subprocess for adjusting ink detachment. 
   
   
       18 . A method as claimed in  claim 1 , wherein generating a control variable by means of the measurement results in the controller of the dispersing subprocess for adjusting ink detachment. 
   
   
       19 . A method as claimed in  claim 1 , wherein generating a control variable by means of the measurement results in the controller of the pulping subprocess for keeping detached ink separate from fibres. 
   
   
       20 . A method as claimed in  claim 1 , wherein generating a control variable by means of the measurement results in the controller of the dispersing subprocess for keeping detached ink separate from fibres. 
   
   
       21 . A method as claimed in  claim 1 , wherein generating a control variable by means of the measurement results in the controller of the dispersing subprocess for adjusting specific energy consumption in the dispersing subprocess. 
   
   
       22 . A method as claimed in  claim 1 , wherein generating a control variable by means of the measurement results in the controller of the dispersing subprocess for mixing bleaching chemicals in the dispersing subprocess. 
   
   
       23 . A method as claimed in  claim 1 , wherein generating a control variable in the controller of the pulping subprocess for adjusting temperature in the pulping subprocess. 
   
   
       24 . A method as claimed in  claim 1 , wherein generating a control variable in the controller of the dispersing subprocess for adjusting temperature in the dispersing subprocess. 
   
   
       25 . A method as claimed in  claim 1 , wherein measuring at least one of the following; production speed, ash content, water content, from the recycled fibre pulp before the pulping subprocess for controlling the pulping subprocess and/or the dispersing subprocess. 
   
   
       26 . A method as claimed in  claim 1 , wherein measuring the detachment of ink from a filling agent and a coating paste in the recycled fibre pulp, and, on the basis of the measurement results, controlling the pulping subprocess with the controller of the pulping subprocess, and the dispersing subprocess with the controller of the dispersing subprocess to adjust the mechanical processing of the recycled fibre pulp to detach ink. 
   
   
       27 . A method as claimed in  claim 1 , wherein measuring the separation of sticky substances from the recycled fibre pulp and controlling the pulping subprocess with the controller of the pulping subprocess and the dispersing subprocess with the controller of the dispersing process to adjust the mechanical processing of the recycled fibre pulp to detach sticky substances. 
   
   
       28 . A method as claimed in  claim 1 , wherein feeding forward the controller of the pulping subprocess to the controller of the dispersing subprocess for taking into account the control of the pulping subprocess in the control of the dispersing process. 
   
   
       29 . A recycled fibre line comprising a pulping subprocess and a dispersing subprocess, and wherein recycled fibre pulp is processed, wherein the recycled fibre line comprises
 a controller of the pulping subprocess Wand a controller of the dispersing subprocess, the controllers being adapted to perform multivarable-based predictive calculation and optimization of control functions;   measuring devices for measuring at least one characteristic of ink and at least one of the following: number of fibre bundles, number of fibres attached to each other in at least one measuring point, and the measuring devices are adapted to feed measurement results to the controller of the pulping subprocess and to the controller of the dispersing subprocess,   the controller of the pulping subprocess is adapted to generate, on the basis of the measurement results, at least one control variable for chemical processing of the recycled fibre pulp performed in the pulping subprocess and at least one control variable mechanical processing performed in the pulping subprocess, and   the controller of the dispersing subprocess is adapted to generate, on the basis of the measurement results, at least one control variable for chemical processing of the recycled fibre pulp performed in the dispersing subprocess and at least one control variable for mechanical processing of the recycled fibre pulp performed in the dispersing subprocess.   
   
   
       30 . A recycled fibre line as claimed in  claim 29 , wherein the measuring devices are arranged to measure at least one characteristic of the fibres of the recycled fibre pulp and at least characteristic of the ink between the pulping subprocess and the dispersing subprocess and the measuring devices are arranged to feed the measurement results to the controller of the pulping subprocess and to the controller of the dispersing process; and
 the measuring devices are arranged to measure at least one characteristic of the fibres of the recycled fibre pulp and at least one characteristic of the ink after the dispersing subprocess and the measuring devices are arranged to feed the measurement results to the controller of the pulping subprocess and to the controller of the dispersing subprocess.   
   
   
       31 . A recycled fibre line as claimed in  claim 29 , wherein the measuring devices are arranged to measure at least one of the following characteristics determining fibre quality: fibre length, amount of fibrous fine material, drainability, and the controller the pulping subprocess and the controller of the dispersing subprocess are arranged to generate at least one control variable affecting the processing of the fibres on the basis of the measurement and a model. 
   
   
       32 . A recycled fibre line as claimed in  claim 29 , that wherein the measuring devices are arranged to measure at least one of the following characteristics determining fibre detachment: number of fibre bundles, number of fibres attached to each other, and the controller of the pulping subprocess and the controller of the dispersing subprocess are arranged to generate at least one control variable affecting the processing of the fibres on the basis of the measurement and a model. 
   
   
       33 . A recycled fibre line as claimed in  claim 29 , herein the measuring devices are arranged to measure at least one of the following ink-determining characteristics: amount of ink attached to fibres, amount of free ink, brightness of the recycled fibre pulp, amount of ink removed in washing, amount of ink not removed in washing, size distribution of free ink particles, and the controller of the pulping subprocess and the controller of the dispersing subprocess are arranged to generate at least one control variable affecting the processing of the ink on the basis of the measurement and a model. 
   
   
       34 . A recycled fibre line as claimed in  claim 29 , wherein the controller of the pulping subprocess is arranged to determine, on the basis of at least one measurement, a fibre parameter descriptive of the detachment of fibres from each other, and to use the parameter in the generation of at least one control variable; and the controller of the pulping subprocess is arranged to determine, on the basis of at least one measurement, an ink parameter descriptive of the detachment of ink particles from each other, and to use the parameter in the generation of at least one control variable. 
   
   
       35 . A recycled fibre line as claimed in  claim 29 , wherein the controller G of the dispersing subprocess is arranged to determine, on the basis of at least one measurement, a fibre parameter descriptive of the detachment of fibres from each other, and to use the parameter in the generation of at least one control variable; and controller of the dispersing subprocess is arranged to determine, on the basis of at least one measurement, an ink parameter descriptive of the detachment of ink particles from each other, and to use the parameter in the generation of at least one control variable. 
   
   
       36 . A recycled fibre line as claimed in  claim 29 , wherein the controller of the pulping subprocess is arranged to generate at least one chemical parameter for controlling for controlling the dosage of chemicals into the recycled fibre process; and the controller of the pulping subprocess is arranged to generate at least one mechanical parameter for controlling the mechanical processing of the recycled fibre process. 
   
   
       37 . A recycled fibre line as claimed in  claim 29 , wherein the controller of the dispersing subprocess is arranged to generate at least one chemical parameter for controlling the dosage of chemicals into the recycled fibre process; and the controller of the dispersing subprocess is arranged to generate at least one mechanical parameter for controlling the mechanical processing of the recycled fibre process. 
   
   
       38 . A recycled fibre line as claimed in  claim 29 , wherein the controller of the pulping subprocess is arranged to control a continuous pulper. 
   
   
       39 . A recycled fibre line as claimed in  claim 29 , wherein the controller of the pulping subprocess is arranged to control a batch pulper. 
   
   
       40 . A recycled fibre line as claimed in  claim 29 , wherein the controller of the pulping subprocess is arranged to generate a control variable by means of the measurement results for adjusting the consistency of the pulping subprocess. 
   
   
       41 . A recycled fibre line as claimed in  claim 29 , wherein the controller of the pulping subprocess is arranged to generate a control variable by means of the measurement results for adjusting the speed of rotation of a pulper. 
   
   
       42 . A recycled fibre line as claimed in  claim 29 , wherein the controller of the pulping subprocess is arranged to generate a control variable by means of the measurement results for adjusting pulping time. 
   
   
       43 . A recycled fibre line as claimed in  claim 29 , wherein the controller of the pulping subprocess is arranged to generate a control variable by means of the measurement results for adjusting fibre swelling. 
   
   
       44 . A recycled fibre line as claimed in  claim 29 , wherein the controller of the dispersing subprocess is arranged to generate a control variable by means of the measurement results for adjusting fibre swelling. 
   
   
       45 . A recycled fibre line as claimed in  claim 29 , wherein the controller of the pulping subprocess is arranged to generate a control variable by means of the measurement results for adjusting ink detachment. 
   
   
       48 . A recycled fibre line as claimed in  claim 29 , wherein the controller of the dispersing subprocess is arranged to generate a control variable by means of the measurement results for adjusting ink detachment. 
   
   
       47 . A recycled fibre line as claimed in  claim 29 , wherein the controller of the pulping subprocess is arranged to generate a control variable by means of the measurement results for keeping detached ink separate from fibres. 
   
   
       48 . A recycled fibre line as claimed in  claim 29 , wherein the controller of the dispersing subprocess is arranged to generate a control variable by means of measurement results for keeping detached ink separate from fibres. 
   
   
       49 . A recycled fibre line as claimed in  claim 29 , wherein the controller of the dispersing subprocess is arranged to generate a control variable by means of measurement results for adjusting specific energy consumption in the dispersing subprocess. 
   
   
       50 . A recycled fibre line as claimed in  claim 29 , wherein the controller of the dispersing subprocess is arranged to generate a control variable by means of measurement results for mixing bleaching chemicals into the dispersing subprocess of the recycled fibre pulp. 
   
   
       51 . A recycled fibre line as claimed in  claim 29 , wherein the controller of the pulping subprocess his arranged to generate a control variable for adjusting the temperature in the pulping subprocess. 
   
   
       52 . A recycled fibre line as claimed in  claim 29 , wherein the controller of the dispersing subprocess is arranged to generate a control variable for adjusting the temperature in the dispersing subprocess. 
   
   
       53 . A recycled fibre line as claimed in  claim 29 , wherein the recycled fibre line comprises measuring devices for measuring, from the recycled fibre pulp, before the pulping subprocess, at least one of the following: production speed, ash content, water content, and the controller is arranged, on the basis of the measurement results, to control the pulping subprocess and/or the dispersing subprocess. 
   
   
       54 . A recycled fibre line as claimed in  claim 29 , wherein the measuring devices between the pulping subprocess and the dispersing subprocess and after the dispersing process are arranged to measure the detachment of ink from a filling agent and a coating paste in the recycled fibre pulp, and the controller of the pulping subprocess and the controller of the dispersing subprocess are arranged to adjust, on the basis of the measurement results, the mechanical processing of the recycled fibre pulp to detach ink in the pulping subprocess and in the dispersing subprocess. 
   
   
       55 . A recycled fibre line as claimed in  claim 29 , wherein the measuring devices between the pulping subprocess and the dispersing subprocess and after the dispersing process are arranged to measure the separation of sticky substances in the recycled fibre pulp, and the controller of the pulping subprocess and the controller of the dispersing subprocess are arranged to adjust, on the basis of measurement results, the mechanical processing of the recycled fibre pulp to detach sticky substances in the pulping subprocess and in the dispersing subprocess. 
   
   
       56 . A recycled fibre line as claimed in  claim 29 , wherein the controller of the pulping subprocess is fed forward to the controller of the dispersing subprocess for taking into account the control of the pulping subprocess the control of the dispersing process.