Method of adjusting pulp washing process and determining efficiency

Abstract

A method of adjusting a pulp washing process and measuring efficiency. The methods comprise modelling the maximum washing capacity of the washing process, selecting the variables of the washing process to be measured, measuring the variables of the washing process, and adjusting the washing process or determining the efficiency of the washing process by means of the modelling and the measurements.

1 . A method of adjusting a pulp washing process, characterized by 
 modelling the maximum washing capacity of the washing process by a dynamic model,    selecting the variables of the washing process to be measured,    measuring the variables of the washing process, and    adjusting the washing process by means of the modelling and the measurements, wherein the maximum washing capacity of the washing process is described by its washing potential in diffusion and wherein the washing potential in diffusion is determined in the following manner:                    Q   diff     =     k        ∫       ∑     i   =   1     n            (       x   i          ∇       c   i          (   t   )           )               -   yt                 zT        (   t   )                 t                     (   1   )                           wherein Q diff =washing potential in diffusion, k=scaling coefficient, c i =variables describing concentrations, change in conductivity or in cod or in consistencies, t=time, t=temperature while x, y and z are weighting coefficients and constants:    
     
     
         2 . A method as claimed in  claim 1 , characterized by optimizing the washing process on the basis of the modelling and the measurements.  
     
     
         3 . A method as claimed in  claim 1  or  2 , characterized by adjusting the operation of the washing process on-line.  
     
     
         4 . A method as claimed in any one of the preceding claims, characterized in that the pulp to be washed is brown pulp.  
     
     
         5 . A method as claimed in any one of  claims 1  to  3 , characterized in that the washing process takes place in a pulp bleaching process.  
     
     
         6 . A method as claimed in any one of the preceding claims, characterized in that the washing process to be adjusted comprises an entire washing line.  
     
     
         7 . A method as claimed in any one of  claims 1  to  5 , characterized in that the washing process to be adjusted takes place in a single washer.  
     
     
         8 . A method as claimed in any one of the preceding claims, characterized in that the modelling of the maximum washing capacity of the washing process is applied as a Soft Sensor.  
     
     
         9 . A method of determining the efficiency of a pulp washing process, characterized by 
 modelling the maximum washing capacity of the washing process,    selecting the variables of the washing process to be measured,    measuring the variables of the washing process, and    determining the efficiency of the washing process by means of the modelling and the measurements, wherein the efficiency of the washing process is described by a dynamic model and by its washing potential in diffusion and wherein the washing potential in diffusion is determined in the following manner:                    Q   diff     =     k        ∫       ∑     i   =   1     n            (       x   i          ∇       c   i          (   t   )           )               -   yt                 zT        (   t   )                 t                     (   1   )                           wherein Q diff =washing potential in diffusion, k=scaling coefficient, c i =variables describing concentrations, change in conductivity or in COD or in consistencies, t=time, T=temperature while x, y and z are weighting coefficients and constants.    
     
     
         10 . A method as claimed in  claim 9 , characterized by optimizing the washing process on the basis of the determination of the efficiency of the washing result.  
     
     
         11 . A method as claimed in  claim 9  or  10 , characterized by determining the efficiency of the washing process on-line.  
     
     
         12 . A method as claimed in any one of  claims 9  to  11 , characterized in that the pulp to be washed is brown pulp.  
     
     
         13 . A method as claimed in any one of  claims 9  to  11 , characterized in that the washing process takes place in a pulp bleaching process.  
     
     
         14 . A method as claimed in any one of  claims 9  to  13 , characterized by measuring the efficiency of an entire washing line.  
     
     
         15 . A method as claimed in any one of  claims 9  to  13 , characterized by measuring the efficiency of a single washer.  
     
     
         16 . A method as claimed in any one of  claims 9  to  15 , characterized by applying the modelling of the maximum washing capacity of the washing process as a Soft Sensor.