SE544505C2 - Method and system for controlling an apparatus for treating a pulp slurry - Google Patents

Method and system for controlling an apparatus for treating a pulp slurry

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Publication number
SE544505C2
SE544505C2 SE2150320A SE2150320A SE544505C2 SE 544505 C2 SE544505 C2 SE 544505C2 SE 2150320 A SE2150320 A SE 2150320A SE 2150320 A SE2150320 A SE 2150320A SE 544505 C2 SE544505 C2 SE 544505C2
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SE
Sweden
Prior art keywords
operating parameter
ultrasonic
housing portion
measurement
rotational speed
Prior art date
Application number
SE2150320A
Other languages
Swedish (sv)
Other versions
SE2150320A1 (en
Inventor
Tomas Vikström
Original Assignee
Valmet Oy
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Valmet Oy filed Critical Valmet Oy
Priority to SE2150320A priority Critical patent/SE2150320A1/en
Priority to PCT/SE2022/050223 priority patent/WO2022197230A1/en
Priority to EP22771852.5A priority patent/EP4308915A1/en
Priority to BR112023018651A priority patent/BR112023018651A2/en
Publication of SE544505C2 publication Critical patent/SE544505C2/en
Publication of SE2150320A1 publication Critical patent/SE2150320A1/en

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
    • G01N29/02—Analysing fluids
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C7/00—Digesters
    • D21C7/02—Rotary digesters
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C7/00—Digesters
    • D21C7/06—Feeding devices
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C7/00—Digesters
    • D21C7/12—Devices for regulating or controlling
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
    • D21C9/02—Washing ; Displacing cooking or pulp-treating liquors contained in the pulp by fluids, e.g. wash water or other pulp-treating agents
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
    • D21C9/18—De-watering; Elimination of cooking or pulp-treating liquors from the pulp
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
    • G01F1/66—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by measuring frequency, phase shift or propagation time of electromagnetic or other waves, e.g. using ultrasonic flowmeters
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
    • G01F1/66—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by measuring frequency, phase shift or propagation time of electromagnetic or other waves, e.g. using ultrasonic flowmeters
    • G01F1/667—Arrangements of transducers for ultrasonic flowmeters; Circuits for operating ultrasonic flowmeters
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
    • G01F1/66—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by measuring frequency, phase shift or propagation time of electromagnetic or other waves, e.g. using ultrasonic flowmeters
    • G01F1/663—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by measuring frequency, phase shift or propagation time of electromagnetic or other waves, e.g. using ultrasonic flowmeters by measuring Doppler frequency shift
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2291/00—Indexing codes associated with group G01N29/00
    • G01N2291/02—Indexing codes associated with the analysed material
    • G01N2291/028—Material parameters
    • G01N2291/02836—Flow rate, liquid level

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  • Physics & Mathematics (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Wood Science & Technology (AREA)
  • General Physics & Mathematics (AREA)
  • Biochemistry (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Health & Medical Sciences (AREA)
  • General Health & Medical Sciences (AREA)
  • Acoustics & Sound (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Electromagnetism (AREA)
  • Fluid Mechanics (AREA)
  • Paper (AREA)
  • Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)
  • Processing Of Solid Wastes (AREA)

Abstract

Method for controlling an apparatus (101; 206; 313; 416; 518) for treating biomass containing material, said apparatus comprising a housing portion (104a-b; 208; 417) in which said material flows during treatment, wherein at least one ultrasonic measurement device (105a-b; 205; 305; 405; 505a-b) is provided on an outer surface of said housing portion, which ultrasonic measurement device is configured to transmit ultrasonic pulses into said housing portion and receive reflected ultrasonic pulses therefrom. The method comprises conducting at least one measurement (1) using said at least one ultrasonic measurement device to obtain measurement data indicative of the reflected ultrasonic pulses, adjusting at least one operating parameter (5) for said apparatus based on said measurement data from said at least one ultrasonic measurement device, and controlling operation (6) of said apparatus based on said at least one operating parameter. A corresponding control system for controlling an apparatus for treating biomass containing material and an apparatus comprising such a control system are also provided.

Description

METHOD AND SYSTEM FOR CONTROLLING AN APPARATUS FOR TREATING APULP SLURRY TECHNICAL FIELD The invention relates to the field of apparatuses for treating biomass containing material, and more specifically controlling the operation of such apparatuses.
BACKGROUND Apparatuses for treating biomass containing material are known in the art. For example, ina pulping process, apparatuses such as dewatering and/or washing devices, pressurizedcooking vessels, bleaching towers, storage towers, mixing devices and/or screening devicesare used. Such apparatuses all share the common property that the pulp flows within ahousing portion, for example in the vat of a twin roll press. Today, these flows are norrnallymonitored using pressure and/or temperature sensors, and control of various operatingparameters such as a rotational speed and/or a flow rate of a fluid or suspension associatedwith the apparatus may take place based on these measurements or parameters estimated from these measurements.
There is a need for further improved control of such apparatuses, for example to improve utilization and to avoid channelizing or plugging.
SUMMARY An object of the invention is to solve or improve on at least some of the problems mentioned above in the background section.
These and other objects are achieved by the present invention by means of a method and a control system according to the independent claims.
According to a first aspect of the invention, a method for controlling an apparatus for treatingbiomass containing material is provided. The apparatus comprises a housing portion inwhich said material flows during treatment. At least one ultrasonic measurement device isprovided on an outer surface of said housing portion, which ultrasonic measurement device is configured to transmit ultrasonic pulses into said housing portion and receive reflected ultrasonic pulses therefrom. The method comprises conducting at least one measurementusing the at least one ultrasonic measurement device to obtain measurement data indicativeof the reflected ultrasonic pulses, adjusting at least one operating parameter for saidapparatus based on said measurement data from said at least one ultrasonic measurementdevice, and controlling operation of said apparatus based on said at least one operating parameter.
In other words, an apparatus for treating (washing, dewatering, distributing, mixing forexample) biomass containing material is provided, where the biomass containing materialmay be a suspension comprising biomass particles, which biomass may be lignocellulosecontaining biomass. In particular, the biomass containing material may be a pulp suspensionor slurry. The housing portion of the apparatus may altematively be referred to as a shellportion, compartment, vessel portion or passageway through which the material flows or isconveyed during treatment. The at least one ultrasonic measurement device is provided onan at least one outer surface of the housing portion, which outer surface may also be referredto as an outer surface of a wall portion delimiting the housing portion. It is understood thatthe material flows inside the wall portion on the opposite side of the outer surface. The atleast one ultrasonic measurement device is conf1gured to transmit ultrasonic pulses into thehousing portion and receive reflected or back-scattered ultrasonic pulses therefrom and maycomprise at least one ultrasonic transmitter and at least one ultrasonic receiver for thispurpose. The measurement data obtained by means of the at least one measurementperformed using the at least one ultrasonic measurement device is used to adjust at least oneoperating parameter for the apparatus, i.e. is used to determine new value(s) of the at leastone operating parameter. The adjusted operating parameter is used to control the apparatus.The at least one operating parameter may comprise a rotational speed of the apparatus and/orof an associated device. The at least one operating parameter may comprise a flow rate of afluid or suspension associated with the apparatus. More specifically, the at least oneoperating parameter may be a flow of dilution liquid, which allows the consistency of the biomass containing material to be adjusted.
The invention is based on the insight that further improved control of an apparatus for treating biomass material is achievable by having better knowledge of the material flow inside the apparatus. The inventors have surprisingly realized that such flow measurementsmay be conducted by means of non-invasive ultrasonic measurement devices placed on anouter (metallic) surface of a housing portion of the apparatus. Such measurements mayprovide improved control compared to conducting corresponding ultrasonic measurements upstream and/or downstream of the apparatus in the pipes connected thereto.
Non-invasive ultrasonic measurements techniques per se are known in the art. If the materialcontains a relatively small number of particles, the so-called time transit method may beused, which is based on the principle to conduct two measurements, one measurement withthe ultrasonic beam directed in a downstream direction and one in an upstream direction,and compare the time from when the ultrasonic pulses or signal is transmitted until it isreceived in the upstream measurement with the corresponding time from the downstreammeasurement. The difference in time may be used to determine the flow rate for instance. Ifthe material contains a large number of particles, the so-called doppler shift method may bepreferrable, which is based on the principle that the ultrasonic pulses are transmitted into thehousing portion and reflected or back-scattered on the particles in the material, where thefrequency shift caused by the motion of the particles can be used to determine the flow rate for instance.
In embodiments, the method further comprises estimating a velocity profile of a flow of thematerial in the housing portion based on the obtained measurement data indicative of thereflected ultrasonic pulses. A comparison between the velocity profile and a desiredreference velocity profile may also be performed. The estimated velocity profile and/or the results of the comparison may be used in the adjusting step to adjust the operating parameter.
In embodiments, the method further comprises deterrnining a consistency of the material,wherein said adjusting at least one operating parameter comprises adjusting additionally based on said consistency.
In embodiments, the method further comprises measuring at least one differential pressureusing at least two pressure sensors arranged along a length of the housing and/or measuring at least one temperature of the material using at least one temperature sensor, wherein said at least one Operating parameter for said apparatus is adjusted additionally based on said at least one differential pressure and/or said at least one temperature.
According to a second aspect of the invention, a control system for controlling an apparatusfor treating biomass containing material is provided. The apparatus comprises a housingportion in which said material flows during treatment. The control system comprising anultrasonic measurement device and an electronic control unit to which said ultrasonicmeasurement device is electrically connected. The ultrasonic measurement device isprovided on an outer surface of said housing portion, which ultrasonic measurement deviceconfigured to transmit ultrasonic pulses into said housing portion and receive back-scatteredultrasonic pulses therefrom. The electronic control unit is conf1gured to adjust at least oneoperating parameter for said apparatus based on said measurement data received from saidultrasonic measurement device and generate a control signal for said apparatus based on said at least one operating parameter.
According to a third aspect of the invention, an apparatus for treating biomass containingmaterial is provided. The apparatus comprises a control system according to the secondaspect of the invention or embodiments thereof, wherein the apparatus is electricallyconnected to said electronic control unit of said control system to receive said control signal therefrom.
In embodiments of the first, second or third aspect of the invention, the at least one ultrasonicmeasurement device is arranged such that the ultrasonic beam is directed at an angle relativethe flow direction of the biomass material, for instance at an angle in a range between 10-80degrees, such as between 25-65 degrees, such as about 45 degrees. The angle mayaltematively be defined relative a normal direction of the outer surface of the housingportion, which angle may be in a range between 10-80 degrees, such as between 25-degrees, such as about 45 degrees.
In embodiments of the first, second or third aspect of the invention, the apparatus is adewatering and/or washing apparatus (such as a twin roll press) comprising at least onerotatable drum having a perrneable outer surface, said drum being arranged in a vat, wherein said housing portion is said vat or a portion thereof, wherein the at least one ultrasonic measurement device is conf1gured to transmit said ultrasonic pulses into the vat towards thedrum, preferably at an angle relative the radial direction of the drum. The at least oneoperating parameter may comprise a rotational speed of said at least one drum and/or one ormore flows of dilution liquid upstream of said dewatering and/or washing apparatus and/orone or more flows of wash liquid added in the vat. By adjusting one or more of theseoperating parameters, the flow profile in the vat may be optimized, aiming towards a plugflow profile. Further, by conducting ultrasonic measurements and estimating a Velocityprofile, a measure of the dewatering characteristics may be obtained, which measure may be used to compare different dewatering apparatuses.
The dewatering and/or washing apparatus may be provided with a plurality of ultrasonicmeasurement devices distributed along the axial length of the rotatable drum, wherein saiddeterrnining at least one operating parameter comprises comparing measurement data fromthe plurality of measurement devices. The dewatering and/or washing apparatus norrnallycomprises liquor distribution nozzles which are also distributed along the axial length, whichmeans that the plurality of ultrasonic measurement devices may be used to detect plugging of the nozzles by comparing velocity prof1les over the axial length of the drum/vat.
The dewatering and/or washing apparatus may comprise a device for distribution ofcellulose pulp onto said at least one rotatable drum, wherein said device comprises arotatably arranged distribution screw, and wherein said operating parameters comprises arotational speed of said distribution screw. This embodiment is advantageously combinedwith the above-described embodiment comprising a plurality of ultrasonic measurementdevices. The rotational speed of the distribution screw is advantageously adjusted to achieveas uniform distribution as possible in the axial direction. In other words, an estimated axial uniforrnity may be used in the adjustment of the operating parameter(s).
In another embodiment of the first, second or third aspect of the invention, the apparatus isa device for distribution of material onto a movable processing surface, for example theperrneable outer surface of the drum of the dewatering and/or washing apparatus describedabove. The distribution device comprises an inlet box which comprises an inlet for incoming material and an outlet for transfer of the material to the processing surface, wherein a distribution screw is rotatably arranged in said inlet box, wherein said housing portion is aportion of said inlet box, and wherein said operating parameters comprises a rotational speedof said distribution screw. The device for distribution may furtherrnore comprise throttlingand/or guiding vanes, wherein the operating parameters comprises position parameters forsaid vanes. The device for distribution may be provided with a plurality of ultrasonicmeasurement devices distributed along the axial length of the distribution screw, whereinsaid adjusting at least one operating parameter comprises comparing measurement data fromthe plurality of measurement devices. The rotational speed of the distribution screw and/orthe positions of the vanes is/ are advantageously adjusted to achieve as uniform distributionas possible in the axial direction. In other words, an estimated axial uniforrnity may be used in the adjustment of the operating parameter(s).
In yet another embodiment of the first, second or third aspect of the invention, the apparatusis vessel, for instance a vertical or horizontally disposed vessel, such as a pressurizedcooking vessel, a bleaching tower, a storage tower or the like, wherein said housing portionis a portion of said vessel, and wherein said operating parameters comprises a flow rate ofbiomass containing material into said vessel and/or a flow rate of a dilution liquid into saidvessel. By arranging the ultrasonic measurement device to allow estimation of the velocityprofile along the diameter of the tower, detection of channelling may be detected and actedupon by adjusting one or more of the above-mentioned operating parameters. A verticalvessel may be provided with agitation means in a bottom portion thereof def1ning anagitation zone, wherein at least one ultrasonic measurement device is arranged to transmitultrasonic pulses into said agitation zone, wherein said at least one operating parametercomprises a rotational speed of said agitation means. By conducting ultrasonicmeasurements through the agitation zone, the cavem size can be estimated and adjusted byadjusting the rotational speed of the agitation means. In other words, the estimated cavemsize may be used in the adjustment of the operating parameter(s). Thereby, the cavem sizemay be adjusted to suit the incoming flow of biomass containing material such that suff1cient agitation is achieved.
In yet another embodiment of the first, second or third aspect of the invention, the apparatus is mixing device, wherein said housing portion is a portion of an outlet of said mixing device, and wherein said at least one Operating parameter comprises a rotational speed of saidmixing device. This is advantageous since the homogeneity of the biomass containingmaterial after mixing can be estimated, which estimation may be used in the adjustment of the operating parameter(s).
In yet another embodiment of the first, second or third aspect of the invention, the apparatusis screening device having a screen basked rotatably arranged in a screen housing, whereinsaid housing portion is a portion of said screen housing, and wherein said at least oneoperating parameter comprises a rotational speed of said screen basket. The screening devicemay be provided with at least two ultrasonic measurement devices distributed along theextension of the screen basket. This is advantageous since plugging of the basket may be detected, and if detected, the rotational speed may be increased to attempt to relieve the plugging.
The features of the embodiments described above are combinable in any practicallyrealizable way to form embodiments having combinations of these features. Further, allfeatures and advantages of embodiments described above with reference to the first aspectof the invention may be applied in corresponding embodiments of the second and third aspects of the invention and vice versa.
BRIEF DESCRIPTION OF THE DRAWINGSAbove discussed and other aspects of the present invention will now be described in moredetail using the appended drawings, which show presently preferred embodiments of theinvention, wherein: f1g. l shows a flowchart of an embodiment of the method according to the first aspectof the invention; f1g. 2 shows an embodiment of an apparatus according to the third aspect of theinvention comprising a control system according to the second aspect of the invention; f1g. 3 shows a detail view of the apparatus in fig. 2; f1g. 4 shows an example of an estimated flow profile obtained in an apparatus as shown in f1g. 2-3; f1g. 5 shows another embodiment of an apparatus according to the third aspect of theinVention comprising a control system according to the second aspect of the inVention; f1g. 6 shows yet another embodiment of an apparatus according to the third aspect ofthe inVention comprising a control system according to the second aspect of the inVention; f1g. 7 shows yet another embodiment of an apparatus according to the third aspect ofthe inVention comprising a control system according to the second aspect of the inVention,and f1g. 8 shows yet another embodiment of an apparatus according to the third aspect of the inVention comprising a control system according to the second aspect of the inVention.
DETAILED DESCRIPTION Fig. l shows a flowchart of an embodiment of the method according to the first aspect of theinVention. The method comprises conducting at least one measurement l using at least oneultrasonic measurement device to obtain measurement data indicatiVe of the reflectedultrasonic pulses, adjusting 5 at least one operating parameter for said apparatus based onsaid measurement data from said at least one ultrasonic measurement device, and controlling 6 operation of said apparatus based on said at least one operating parameter.
The method optionally comprises estimating 2 a Velocity profile of a flow of the material inthe housing portion based on the obtained measurement data indicatiVe of the reflectedultrasonic pulses, A comparison between the Velocity profile and a desired reference Velocityprofile may also be performed. The estimated Velocity profile and/or the results of the comparison may be used in the adjusting step 5 to adjust the operating parameter.
The method optionally comprises deterrnining a consistency 3 of the material, wherein saidadjusting 5 at least one operating parameter comprises adjusting additionally based on saidconsistency. The method optionally comprises measuring at least one differential pressure 4using at least two pressure sensors arranged along a length of the housing and/or measuringat least one temperature of the material using at least one temperature sensor. The at leastone operating parameter for said apparatus is adjusted 5 additionally based on said at least one differential pressure and/or said at least one temperature.
Fig. 2 shows a cross-section view of an embodiment of an apparatus 101 according to thethird aspect of the invention comprising a control system 121 according to the second aspectof the invention. The apparatus is a dewatering and washing apparatus or more specificallya twin roll press. The twin roll press will only be briefly described herein since it is wellknown to the person skilled in the art. The press comprises a rotatable drum 102b having aperrneable outer surface 103b, the drum being arranged in a vat 103b. An ultrasonicmeasurement device 105b is arranged on the outside of the vat, i.e. the housing portion is aportion of the vat. The ultrasonic measurement device is configured to transmit saidultrasonic pulses into the vat towards the drum at an angle relative the radial direction of thedrum (see f1g. 3). A wash liquor injection nozzles 111b is arranged adjacent and upstreamof the ultrasonic measurement device 105b. Although not shown in the cross-section viewin f1g. 2, it is understood that a plurality of wash liquor injection nozzles are distributed onthe drum along the axial length thereof. In the same manner, a plurality of ultrasonic measurement devices are distributed along the axial length.
The electronic control unit (ECU) 121 is electrically connected to the ultrasonicmeasurement device 105b and also to drum driving means (for instance an electrical motor,shown schematically as a dotted circle within the drum 102b), to the wash liquor injectionnozzle 111b, and may furtherrnore be connected to dilution liquid nozzles upstream of thevat (not shown in f1g. 2). The operating parameters thus comprise a rotational speed of thedrum, flows of wash liquid added in the vat and optionally one or more flows of dilution liquid.
The twin roll press if furtherrnore provided with a device 106b for distribution of materialonto the perrneable outer surface 103b of the drum 102b. The distribution device comprisesan inlet box 108b which comprises an inlet 109b for incoming material and an outlet 110bfor transfer of the material onto the drum. A distribution screw 107b is rotatably arranged insaid inlet box. The ECU 121 may optionally be electrically connected with driving meanssuch as an electric motor for the distribution screw. The operating parameters may thus comprise also the rotational speed of the distribution screw.
The description above regarding drum l02b also applies to the other drum l02a withperrneable surface l03a arranged in vat l04a, provided with wash liquor injection nozzlellla, ultrasonic measurement device l05a and device for distribution l06a with inlet box l08a, inlet l09a, outlet ll0a and distribution screw l07a.
Fig. 3 shows a detail view of the apparatus in f1g. 2. Here, it can be seen that the ultrasonicbeam, illustrated as a dotted arrow, is at an angle relative the direction of biomass containingmaterial flow, indicated as an arrow between perrneable outer surface l03b of the drum andvat l04b. It is understood that the direction of the ultrasonic beam and the transducer part ofthe ultrasonic measurement device are only schematically shown - the beam will bedeflected when passing through the housing portion wall. The ultrasonic measurementdevices in this embodiment (and all other embodiments described herein) may be of the typedisclosed in f1g. 7 of WO 2013/017969, which is a doppler shift type of device comprisingone or more ultrasonic transducers. Other types of ultrasonic measurement devices andconf1gurations thereof are of course also viable within the scope of the invention, for example having transducers and receivers arranged in a V-, W- or Z-configuration.
Fig. 4 shows an example of an estimated flow profile obtained in an apparatus as shown inf1g. 2-3. As can be seen, the flow velocity is close to zero at the vat wall (distance 0 mm).By using the inventive method, the operating parameters have been adjusted such that theflow velocity is substantially constant over a substantial part of the distance between the perrneable outer surface and the vat.
Fig. 5 shows a cross-section view of another embodiment of an apparatus according to thethird aspect of the invention comprising a control system according to the second aspect ofthe invention. The apparatus is a device 206 for distribution of material onto a movableprocessing surface 203, for example the perrneable outer surface of the drum of thedewatering and/or washing apparatus shown in f1g. 2-3. The distribution device comprisesan inlet box 208 which comprises an inlet (not shown) for incoming material and an outlet2l0 for transfer of the material to the processing surface 203, wherein a distribution screw207 is rotatably arranged in the inlet box. A plurality of ultrasonic measurement devices(only one can be seen in the f1g. 5) are fixed to an outer surface of the inlet box and aredistributed along the axial length of the distribution screw. Throttling vanes 222 are arrangedat the outlet 210. An electric actuator 223 is provided to adjust the positions of the throttlingvanes. The ECU 221 is electrically connected to the ultrasonic measurement devices 205and also to screw driving means (for instance an electrical motor, shown schematically as adotted circle within the screw 207), to the vane actuator(s) 223, and may furtherrnore beconnected to dilution liquid nozzles upstream of the device (not shown in f1g. 5). Theoperating parameters thus comprise a rotational speed of the screw, vane position(s) and optionally one or more flows of dilution liquid.
Fig. 6 shows a cross-section view of yet another embodiment of an apparatus according tothe third aspect of the invention comprising a control system according to the second aspectof the invention. The apparatus is vertical vessel 313, more specifically a pressurizedcooking vessel (digester). The vessel is be provided with agitation means 314 (a rotor) at abottom portion thereof def1ning an agitation zone 315, wherein an ultrasonic measurementdevice 305 is arranged to transmit ultrasonic pulses into the agitation zone. The ECU 321 iselectrically connected to the ultrasonic measurement device 305 and also to driving meansfor the rotor 314 (for instance an electrical motor, shown schematically below the rotor) andoptionally to one or more flow adjusting means (such as valves) for adjusting a flow rate ofbiomass containing material into said vessel (inlet shown at top of the vessel 313) and/or aflow rate of a dilution liquid into said vessel (shown as arrows in fig. 6). The ECU mayfurtherrnore be connected to dilution liquid nozzles upstream of the device (not shown inf1g. 5). The operating parameters thus comprise a rotational speed of the agitation means and optionally one or more flows of biomass containing material and/or dilution liquid.
Fig. 7 shows a cross-section view of yet another embodiment of an apparatus according tothe third aspect of the invention comprising a control system according to the second aspectof the invention. The apparatus is mixing device 416 of the type disclosed in WO2020/091640, but may be any type of mixer known in the art. The inlet to the mixer is shownto the left, and the outlet 417 is at the top. An ultrasonic measurement device 405 is arrangedon the outer surface of the outlet 417, which thus forms the housing portion. The ECU 421is electrically connected to the ultrasonic measurement device 405 and also to driving means (for instance an electrical motor, shown schematically to the right of the mixing device) forthe rotor drum (shown as dotted lines inside the mixing device). The operating parameters thus comprise a rotational speed of the rotor drum.
Fig. 8 shows a cross section view of yet another embodiment of an apparatus according tothe third aspect of the invention comprising a control system according to the second aspectof the invention. The apparatus is screening device 518 having a screen basket 519 rotatablyarranged in a screen housing. Screening devices of this type are well known in the art andwill not be described in further detail herein. At least two ultrasonic measurement devices505a-b are distributed along the vertical extension of the screen basket 519. The ECU 521is electrically connected to the ultrasonic measurement devices 505a-b and also to drivingmeans (for instance an electrical motor, shown schematically at the bottom of the figure) forthe screen basket. The operating parameters thus comprise a rotational speed of the screen basket.
The description above and the appended drawings are to be considered as non-limitingexamples of the invention. The person skilled in the art realizes that several changes andmodifications may be made within the scope of the invention. For example, the number ofultrasonic measurement devices may be different, and may be of a different type, and may be arranged with its ultrasonic beam having a different direction.

Claims (1)

1. A method for controlling an apparatus (101; 206; 313; 416; 518) for treating a pulp slurry, said apparatus (101; 206; 313; 416; 518) comprising a housing portion (104a-b; 208; 417) in Which said pulp slurry flows during treatment, Wherein at least oneultrasonic measurement device (105a-b; 205; 305; 405; 505a-b) is provided on anouter surface of said housing portion (104a-b; 208; 417), Which ultrasonicmeasurement device (105a-b; 205; 305; 405; 505a-b) is configured to transmitultrasonic pulses into said housing portion (104a-b; 208; 417) and receive reflectedultrasonic pulses therefrom, said method comprising: conducting at least one measurement (1) using said at least one ultrasonicmeasurement device (105a-b; 205; 305; 405; 505a-b) to obtain measurement dataindicative of the reflected ultrasonic pulses; adjusting at least one operating parameter (5) for said apparatus (101; 206; 313; 416;518) based on said measurement data from said at least one ultrasonic measurementdevice (105a-b; 205; 305; 405; 505a-b), and controlling operation (6) of said apparatus (101; 206; 313; 416; 518) based on said at least one operating parameter (5). . Method according to claim 1, Wherein said at least one operating parameter (5) comprises a rotational speed of said apparatus (101; 206; 313; 416; 518) and/or of an associated device. . Method according to claim 1, Wherein said at least one operating parameter comprises a flow rate of a fluid or suspension associated With said apparatus (101; 206; 313; 416; 518). . Method according to any of the preceding claims, further comprising estimating (2) a velocity profile of a flow of said pulp slurry in said housing portion (104a-b; 208;417) based on said measurement data, Wherein said adjusting comprises using the estimated velocity profile to adjust said operating parameter (5). . Method according to any of the preceding claims, further comprising deterrnining (3) a consistency of the pulp slurry, Wherein said at least one operating parameter (5)for said apparatus (101; 206; 313; 416; 518) is adjusted additionally based on said consistency.Method according to any of the preceding claims, further comprising measuring (4)at least one differential pressure using at least two pressure sensors arranged along alength of the housing and/or measuring at least one temperature of the pulp slurryusing at least one temperature sensor, wherein said at least one operating parameter(5) for said apparatus (101; 206; 313; 416; 518) is adjusted additionally based onsaid at least one differential pressure and/or said at least one temperature. Method according to any of the preceding claims, wherein said apparatus (101; 206;313; 416; 518) is a dewatering and/or washing apparatus (101) comprising at leastone rotatable drum (102a-b) having a perrneable outer surface (103a-b), said at leastone rotatable drum (102a-b) being arranged in a vat (104a-b), wherein said housingportion (104a-b; 208; 417) is a portion of said vat (104a-b), wherein said at least oneultrasonic measurement device (105 a-b) is conf1gured to transmit said ultrasonicpulses into the vat (104a-b). Method according to claim 7, wherein said dewatering and/or washing apparatus(101) is provided with a plurality of ultrasonic measurement devices (105 a-b)distributed along the axial length of the rotatable drum (102a-b), wherein saiddeterrnining at least one operating parameter (5) comprises comparing measurementdata from the plurality of measurement devices. Method according to any of claims 7-8, wherein said at least one operating parameter(5) comprises a rotational speed of said at least one drum (102a-b). Method according to any of claims 7-9, wherein said at least one operating parameter(5) comprises a flow of dilution liquid upstream of said dewatering and/or washingapparatus (101). Method according to any of claims 7-10, wherein said at least one operatingparameter (5) comprises a flow of wash liquid added into the vat by means of at leastone wash liquid nozzle (111a-b). Method according to any of claims 7-11, wherein said apparatus (101) comprises adevice (106a-b) for distribution of cellulose pulp onto said at least one rotatable drum(104a-b), wherein said device (106a-b) comprises a rotatably arranged distributionscrew (107a-b), and wherein said operating parameter (5) comprises a rotational speed of said distribution screw (107a-b).Method according to any of the claims 1-6, wherein said apparatus (101; 206; 313;416; 518) is a device (106a-b; 206) for distribution of material onto a movableprocessing surface (103a-b; 203), wherein the device comprises an inlet box (108a-b; 208) which comprises an inlet (109a-b) for incoming material and an outlet(110a-b; 210) for transfer of the material to the movable processing surface (103a-b; 203),wherein a distribution screw (107a-b; 207) is rotatably arranged in said inlet box(108a-b; 208), wherein said housing portion (104a-b; 208; 417) is a portion of saidinlet box (108a-b; 208), and wherein said operating parameter (5) comprises arotational speed of said distribution screw (107a-b; 207). Method according to claim 13, wherein said device (206) comprises throttling and/orguiding vanes (211), and wherein said operating parameter (5) comprises positionparameters for said guiding vanes (211). Method according to any of the claims 1-6, wherein said apparatus (101; 206; 313;416; 518) is a treatment vessel (313) such as a pressurized cooking vessel, ableaching tower, a storage tower or the like, wherein said housing portion (104a-b;208; 417) is a portion of said treatment vessel (313), and wherein said operatingparameter (5) comprises a flow rate of lignocellulose containing material into saidvertical vessel and/or a flow rate of a dilution liquid into said treatment vessel (313).Method according to claim 15, wherein said treatment vessel (313) is a verticaltreatment vessel (313) provided with agitation means (314) in a bottom portionthereof def1ning an agitation zone (315), wherein at least one ultrasonic measurementdevice (305) is arranged to transmit ultrasonic pulses into said agitation zone (315),wherein said at least one operating parameter (5) comprises a rotational speed of saidagitation means (314). Method according to any of the claims 1-6, wherein said apparatus (101; 206; 313;416; 518) is mixing device (416), wherein said housing portion (104a-b; 208; 417)is a portion of an outlet (417) of said mixing device (416), and wherein said at leastone operating parameter (5) comprises a rotational speed of said mixing device (416).Method according to any of the claims 1-6, wherein said apparatus (101; 206; 313;416; 518) is screening device (518) having a screen basket (519) rotatably arrangedin a screen housing (520), wherein said housing portion (104a-b; 208; 417) is aportion of said screen housing (520), and Wherein said at least one operatingparameter (5) comprises a rotational speed of said screen basket (519).A control system for controlling an apparatus (101; 206; 313; 416; 518) for treatinga pulp slurry, said apparatus (101; 206; 313; 416; 518) comprising a housing portion(104a-b; 208; 417) in Which said pulp slurry floWs during treatment, said controlsystem comprising:at least one ultrasonic measurement device (105a-b; 205; 305; 405; 505a-b) providedon an outer surface of said housing portion (104a-b; 208; 417), Which at least oneultrasonic measurement device (105a-b; 205; 305; 405; 505a-b) is configured totransmit ultrasonic pulses into said housing portion (104a-b; 208; 417) and receivereflected ultrasonic pulses therefrom, and an electronic control unit (121; 221; 321; 421; 521) to Which said ultrasonic measurement device (105a-b; 205; 305; 405; 505a-b) is electrically connected,Wherein said electronic control unit is (121; 221; 321; 421; 521) configured to: - order the ultrasonic measurement device (105a-b; 205; 305; 405; 505a-b) toconduct at least one measurement to obtain measurement data indicative of thereflected ultrasonic pulses; - adjust at least one operating parameter (5) for said apparatus (101; 206; 313;416; 518) based on said measurement data received from said ultrasonicmeasurement device (105a-b; 205; 305; 405; 505a-b), and - generate a control signal for said apparatus (101; 206; 313; 416; 518) based onsaid at least one operating parameter (5). An apparatus (101; 206; 313; 416; 518) for treating a pulp slurry, said apparatus(101; 206; 313; 416; 518) comprising a control system according to claim 19,Wherein said apparatus (101; 206; 313; 416; 518) is electrically connected to saidelectronic control unit (121; 221; 321; 421; 521) of said control system to receive said control signal therefrom.
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SE2150320A SE2150320A1 (en) 2021-03-19 2021-03-19 Method and system for controlling an apparatus for treating a pulp slurry
PCT/SE2022/050223 WO2022197230A1 (en) 2021-03-19 2022-03-08 Method and system for controlling an apparatus for treating a pulp slurry
EP22771852.5A EP4308915A1 (en) 2021-03-19 2022-03-08 Method and system for controlling an apparatus for treating a pulp slurry
BR112023018651A BR112023018651A2 (en) 2021-03-19 2022-03-08 METHOD AND CONTROL SYSTEM FOR CONTROLING AN APPARATUS FOR TREATING A CELLULOSE PULP, AND, APPARATUS

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JP2005077135A (en) * 2003-08-28 2005-03-24 Mitsubishi Paper Mills Ltd Measuring instrument for degree of beating of pulp and its control device
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