Systems and methods for monitoring reject streams from fiber processing units

Abstract

A fiber processing system includes a fiber processing unit having an inlet, accepts outlet, and solid discharge outlet and configured to remove solid contaminants from a fiber-containing stream to produce an accepts stream exiting the accepts outlet and a solid discharge stream exiting the solid discharge outlet. The fiber processing system includes an optical system having an imaging device and image processing system. The imaging device is configured to capture images of the solid discharge stream at or downstream of the solid discharge outlet, and the image processing system is configured to determine relative fiber content, a relative generation rate, types of materials in, or combinations thereof of the solid discharge stream from the captured images. The fiber content, generation rate, and/or types of materials of the solid discharge stream are used to control operation of the fiber processing system or other upstream pulp processing equipment.

1 . A fiber processing system comprising:
 a fiber processing unit comprising an inlet, an accepts outlet, and a solid discharge outlet, wherein the fiber processing unit is configured to remove solid contaminants from a fiber-containing feed stream to produce a fiber processing accepts stream exiting the accepts outlet and to generate a solid discharge stream comprising the solid contaminants and exiting the solid discharge outlet; and   an optical system comprising at least one imaging device and an image processing system, wherein:
 the at least one imaging device is configured to capture at least one image of the solid discharge stream at or downstream of the solid discharge outlet; and 
 the image processing system is configured to determine a relative fiber content in the solid discharge stream, a relative rate of generation of the solid discharge stream, types of one or more materials in the solid discharge stream, or combinations thereof from the at least one image. 
   
     
     
         2 . The fiber processing system of  claim 1 , further comprising a control system comprising at least one processor, at least one memory module, and machine readable and executable instructions stored on the at least one memory module, wherein the control system is communicatively coupled to the image processing system and the machine readable and executable instructions, when executed by the processor, cause the control system to automatically:
 receive one or more signals from the image processing system indicative of the relative fiber content in the solid discharge stream, the relative rate of generation of the solid discharge stream, the types of one or more materials in the solid discharge stream, or combinations thereof; and   control one or more controlled variables of the fiber processing unit based on the relative fiber content in the solid discharge stream, the relative rate of generation of the solid discharge stream, the types of one or more materials in the solid discharge stream, or combinations thereof.   
     
     
         3 . The fiber processing system of  claim 2 , wherein the one or more controlled variables of the fiber processing system comprise a flow rate of dilution water added to the fiber-containing stream upstream of the fiber processing unit, a flow rate of wash water introduced to the fiber processing unit, a production rate or speed of the fiber processing unit, a pressure of the fiber-containing stream to the fiber processing unit, a flow rate of the fiber-containing stream to the fiber processing unit, a flow rate of the fiber processing accepts stream exiting the fiber processing unit, a flow rate of the solid discharge stream exiting the fiber processing unit, or combinations thereof. 
     
     
         4 . The fiber processing system of  claim 2 , further comprising a consistency meter disposed in the fiber processing accepts stream downstream of the fiber processing unit, wherein the consistency meter is configured to measure a consistency of the fiber processing accepts stream exiting the fiber processing unit, wherein the consistency meter is communicatively coupled to the control system, and the machine readable and executable instructions, when executed by the processor, may cause the control system to automatically:
 receive one or more signals from the consistency meter indicative of the consistency of the fiber processing accepts stream; and   control one or more controlled variables of the fiber processing unit based at least in part on the consistency of the fiber processing accepts stream.   
     
     
         5 . The fiber processing system of  claim 1 , wherein the at least one imaging device is positioned to capture the at least one image of the solid discharge stream as the solid discharge stream exits the solid discharge outlet. 
     
     
         6 . The fiber processing system of  claim 1 , further comprising a solids conveyor downstream of the solid discharge outlet, wherein the solids conveyor receives the solid discharge stream exiting the solid discharge outlet and the at least one imaging device is positioned to capture the at least one image of the solid discharge stream on the solids conveyor downstream of the solid discharge outlet. 
     
     
         7 . The fiber processing system of  claim 6 , further comprising a spreader coupled to the solids conveyor, wherein the spreader is configured to spread out the solid discharge stream over a width of the solids conveyor and the at least one imaging device is positioned to capture the at least one image of the solid discharge stream on the solids conveyor downstream of the spreader. 
     
     
         8 . The fiber processing system of  claim 6 , further comprising a shredder downstream of the solids conveyor and a second solids conveyor downstream of the shredder, wherein the at least one imaging device is positioned to capture the at least one image of the solid discharge stream on the second solids conveyor downstream of the shredder. 
     
     
         9 . The fiber processing system of  claim 1 , wherein the fiber processing unit comprises a drum screen unit, a detrasher, a drum pulper, a reject compactor, a sand separator, a reject sorter, a fiber refiner, or any combinations thereof. 
     
     
         10 . The fiber processing system of  claim 1 , wherein the fiber processing unit is a drum screen unit comprising a housing, a rotating drum screen disposed within the housing, an inlet, a filtrate outlet, and a drum screen reject outlet, wherein the at least one imaging device is configured to capture at least one image of a drum screen reject stream at or downstream of exiting the drum screen reject outlet and the image processing system is configured to determine a relative fiber content of the drum screen reject stream, a relative rate of generation of the drum screen reject stream, types of one or more materials in the drum screen reject stream, or combinations thereof. 
     
     
         11 . The fiber processing system of  claim 10 , further comprising a control system comprising at least one processor, at least one memory module, and machine readable and executable instructions stored on the at least one memory module, wherein:
 the control system is communicatively coupled to the image processing system and to the drum screen unit; and   the machine readable and executable instructions, when executed by the processor, cause the control system to automatically:
 receive one or more signals from the image processing system indicative of the relative fiber content of the drum screen reject stream, the relative rate of generation of the drum screen reject stream, the types of the one or more materials in the drum screen reject stream, or combinations thereof; and 
 control one or more controlled variables of the drum screen unit based on the relative fiber content of the drum screen reject stream, the relative rate of generation of the drum screen reject stream, the types of the one or more materials in the drum screen reject stream, or combinations thereof. 
   
     
     
         12 . The fiber processing system of  claim 11 , wherein the one or more controlled variables of the drum screen unit comprise a rotational speed of the rotating drum screen, a flow rate of wash water to the rotating drum screen, a flow rate of dilution water to the drum screen unit, a pressure of the fiber-containing stream to the drum screen unit, a flow rate of the fiber-containing stream to the drum screen unit, a flow rate of a drum screen filtrate exiting the drum screen unit, a flow rate of the drum screen reject stream exiting the drum screen unit, or any combinations thereof. 
     
     
         13 . The fiber processing system of  claim 11 , further comprising a consistency meter on the filtrate outlet of the drum screen unit, wherein the consistency meter is configured to measure a consistency of a drum screen filtrate produce by the drum screen unit, wherein the consistency meter is communicatively coupled to the control system, and the machine readable and executable instructions, when executed by the processor, may cause the control system to automatically:
 receive one or more signals from the consistency meter indicative of the consistency of the drum screen filtrate; and   control one or more controlled variables of the drum screen unit based on the consistency of the drum screen filtrate.   
     
     
         14 . The fiber processing system of  claim 10 , wherein the at least one imaging device is positioned to capture the at least one image of the drum screen reject stream at the drum screen reject outlet, on a first solids conveyor downstream of the drum screen reject outlet, on a second solids conveyor downstream of a shredder, or combinations thereof. 
     
     
         15 . The fiber processing system of  claim 1 , wherein the fiber processing unit is a trash processing unit configured to receive a reject stream from an upstream process and separate the reject stream to produce a trash processing filtrate and a trash processing reject stream comprising solid contaminants, wherein:
 the trash processing unit comprises an inlet, a trash processing filtrate outlet, and a trash processing reject outlet;   the at least one imaging device is configured to capture at least one image of the trash processing reject stream at or downstream of exiting the trash processing reject outlet; and   the image processing system is configured to determine a relative fiber content of the trash processing reject stream, a relative rate of generation of the trash processing reject stream, types of one or more materials in the trash processing reject stream, or any combinations thereof.   
     
     
         16 . A pulp processing system comprising the fiber processing system of  claim 1 , the pulp processing system comprising a pulp production unit, a detrashing system downstream of the pulp production unit, and a coarse screening system downstream of the pulp production unit and parallel to the detrashing system. 
     
     
         17 . The pulp processing system of  claim 16 , wherein the detrashing system comprises a trash well downstream of the pulp production unit, a detrasher unit downstream of the trash well, and a drum screen system downstream of the detrasher, wherein the fiber processing system is the drum screen system, the drum screen system comprises a drum screen unit and the optical system, and the drum screen unit is configured to receive a detrasher reject stream from the detrasher unit and separate the detrasher reject stream to produce a drum screen filtrate and generate a drum screen reject stream. 
     
     
         18 . The pulp processing system of  claim 17 , further comprising a control system operatively coupled to the trash well, the detrasher unit, the drum screen unit, and the optical system, the control system comprising at least one processor, at least one memory module, and computer readable and executable instructions stored on the at least one memory module, wherein the machine readable and executable instructions, when executed by the at least one processor, may cause the control system to automatically:
 receive one or more signals from the optical system indicative of a fiber content of the drum screen reject stream, a relative rate of generation of the drum screen reject stream, types of one or more materials in the drum screen reject stream, or any combinations thereof; and   control one or more controlled variables of the trash well, the detrasher unit, the drum screen unit, or combinations thereof based on the relative fiber content of the drum screen reject stream, a relative rate of generation of the drum screen reject stream, types of one or more materials in the drum screen reject stream, or any combinations thereof.   
     
     
         19 . The pulp processing system of  claim 18 , wherein the one or more controlled variables include a wash water flow rate to the trash well, a dilution water flow rate to the drum screen unit, a rotational speed of the drum screen unit, a wash water flow rate to the drum screen unit, a production rate or speed of the drum screen unit, a pressure of the detrasher reject stream to the drum screen unit, a flow rate of the detrasher reject stream to the drum screen unit, a flow rate of the drum screen filtrate exiting the drum screen unit, a flow rate of the drum screen reject stream exiting the drum screen unit, one or more operating conditions of the detrasher, or combinations thereof. 
     
     
         20 . The pulp processing system of  claim 16 , wherein the coarse screening system comprises a hydrocyclone cleaner system, at least one coarse screening unit downstream of the hydrocyclone cleaner system, and a trash processing unit disposed downstream of the coarse screening unit, wherein the fiber processing unit is the trash processing unit and the trash processing unit is configured to receive a coarse screen reject stream from the coarse screening unit and separate the coarse screen reject stream to produce a trash processing filtrate and generate a trash processing reject stream, wherein the trash processing unit comprises the optical system comprising the at least one imaging device and the image processing system, wherein the at least one imaging device is configured to capture at least one image of the trash processing reject stream exiting the trash processing unit and the image processing system is configured to determine a relative fiber content of the trash processing reject stream, a relative rate of generation of the trash processing reject stream, types of one or more materials in the trash processing reject stream, or any combinations thereof. 
     
     
         21 . The pulp processing system of  claim 20 , further comprising a control system operatively coupled to the hydrocyclone cleaner system, the at least one coarse screening unit, the trashing processing unit, and the optical system, the control system comprising at least one processor, at least one memory module, and computer readable and executable instructions stored on the at least one memory module, wherein the machine readable and executable instructions, when executed by the at least one processor, may cause the control system to automatically:
 receive one or more signals from the optical system indicative of the relative fiber content of the trash processing reject stream, the relative rate of generation of the trash processing reject stream, the types of the one or more materials in the trash processing reject stream, or any combinations thereof; and   control one or more controlled variables of the hydrocyclone cleaner unit, the at least one coarse screening unit, the trash processing unit, or combinations thereof based on the one or more signals.