Classifications

• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21D—TREATMENT OF THE MATERIALS BEFORE PASSING TO THE PAPER-MAKING MACHINE
  • D21D5/00—Purification of the pulp suspension by mechanical means; Apparatus therefor
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21B—FIBROUS RAW MATERIALS OR THEIR MECHANICAL TREATMENT
  • D21B1/00—Fibrous raw materials or their mechanical treatment
  • D21B1/04—Fibrous raw materials or their mechanical treatment by dividing raw materials into small particles, e.g. fibres
  • D21B1/12—Fibrous raw materials or their mechanical treatment by dividing raw materials into small particles, e.g. fibres by wet methods, by the use of steam
  • D21B1/30—Defibrating by other means
  • D21B1/32—Defibrating by other means of waste paper
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21D—TREATMENT OF THE MATERIALS BEFORE PASSING TO THE PAPER-MAKING MACHINE
  • D21D1/00—Methods of beating or refining; Beaters of the Hollander type
  • D21D1/20—Methods of refining
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21D—TREATMENT OF THE MATERIALS BEFORE PASSING TO THE PAPER-MAKING MACHINE
  • D21D99/00—Subject matter not provided for in other groups of this subclass
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
  • Y02W30/00—Technologies for solid waste management
  • Y02W30/50—Reuse, recycling or recovery technologies
  • Y02W30/64—Paper recycling

Definitions

• the subject of the invention is the method of fractionation of waste paper stock during defibering and separate fractions treatment of high flexibility in selection of operation parameters allowing various types of raw materials of diverse defibering properties to be adapted to, which is at the same time energy efficient, that is an important precondition for using in small paper mills for which it is primarily intended.
• the process of waste paper defibering with its simultaneous sorting and cleaning is gradually performed during the waste paper recycling.
• waste paper is disintegrated in the pulper into the form of suspension that obtains the ability to flow to other machines and devices.
• the machines and devices need to continue the defibering process - mainly of paper flakes and separation of heavy and light contaminants, for example foil.
• the amount of fibres and particles of fine organic and mineral fraction released from the raw material constantly increases, which are then subjected to the activity of mechanical forces created within the rotor and of shear stresses - friction in thick pulp, and undergo multiple damage and shredding, as a result of which a large amount of short fibres and fine fraction, particles shorter than about 0.2 mm, is created.
• the papermaking capability of such pulp decreases and its drainability deteriorates - unit resistance to filtration increases, that very adversely influences energy, technological and operational efficiency of the paper machine. This particularly applies to recovered, that is, waste paper fibres, already weakened in the recirculation, recycling process.
• the purpose of the invention is to develop such a method that would allow released fibres and fine fraction particles to be gradually separated and fraction to be treated separately, to obtain pulp of greater average fibre length, better strength and optical properties as well as to improve energy efficiency and cost effectiveness - better use of fibre, sparing application of chemicals.
• the idea is to separate the fragments of waste paper, already defibered in a given moment of the process, as quickly as possible and not to subject them further to the activity of mechanical forces, and to apply separate treatment adapted to diverse fractions.
• the method of fractionation of waste paper stock during defibering and separate fractions treatment according to the invention consists in that during defibering in periodical operation of the pulper, after initial disintegration of waste paper during the time from the moment of material loading, adding water and appropriate increasing of the rotor rotation speed, about 3 - 5 min. depending on the waste paper type, in the first scenario pulp is collected from the pulper tub after slider opening, and it is treated in two operations, the first of which takes place typically in a secondary pulper with a star screen with small-diameter openings, whereas the second operation performed on the stock received from the secondary pulper is carried out according to the invention in a pumping separator with a conical screen with very small round or slotted openings, of the design according to the Polish Patent Application No. P.410382.
• the stock of 2 - 2.5% consistency is separated into two fractions diverse in terms of composition.
• the stock stopped by the conical screen of the pumping separator, constituting one fraction, is pumped back - it circulates to the pulper tub. These are mainly non-defibered stock flakes.
• the received stock which has flown through the screen openings, that is, the second fraction consists of paint particles, fine organic and mineral fraction and fibres which have already been separated from the defibered waste paper, above all the short-fibre fraction.
• the pumping separator collects the stock which has flown through the screen openings in the bottom of the pulper tub without passing through the secondary pulper, that is applicable particularly in case of less contaminated waste paper, for example sorted newspapers and magazines.
• a closed heavy contaminants gravity separator On the way in the suction pipe there is, according to the invention, a closed heavy contaminants gravity separator.
• the stock is diluted before the secondary pulper and in the secondary pulper, thus, according to the invention, it is possible to begin fractionating with the use of the pumping separator fed with the stock which has flown through the openings of the secondary pulper screen earlier.
• the stock pump of the pulper feeds the stock to the centrifugal separator - the cleaner, preferably with a rotor with rotation speed adjustable, preferably automaticaliy, to the stock consistency value.
• a rotor with rotation speed adjustable preferably automaticaliy
• the rotor in the centrifugal separator significantly decreases the impact of consistency and volume jet fluctuations on the efficiency of heavy contaminants separation.
• Unusual location of the centrifugal separator - the cleaner before the homogenisation and storage vat of the pulper influences the system compactness, but above ail it allows the pumping separator to be installed next to this vat, in the place where typically stock pumps are installed, just like previously in case of the pumping separator cooperating with the secondary pulper. It is significant from the energy efficiency point of view.
• the stock from this vat is collected according to the invention by the pumping separator with a conical screen of small opening diameter, for example 1.0 mm, which fractionates the fibre suspension.
• the short fibre fraction is discharged to the vat, from where the stock pump feeds it into a conventional system of multi-stage selective flotation and then to the washing machine which removes the fine fraction, mainly mineral - ash, together with the filtrate.
• the long fibre fraction is sent from the pumping separator to the pressure screen with a cylindrical slotted screen, for example 0.35 mm, and a closed cylindrical rotor, where fine contaminants are removed from the rejects stream. They are discharged onto a flat shaker screen.
• the stock received from the cylindrical screen separator after having been compacted on the compactor, is chanelled under gravity to the high-consistency dispersion system - a screw press, a slow- speed kneading disperser, or to the vat with a propeller mixer, from where the stock pump moves it preferably into a multi-functional refiner according to own concept and design, covered by Polish Patent Application No.
• P.411859 which, apart from energy- and technologically efficient homogenous fibres refining, also carries out to some extent the dispersion process at the consistency which occurs in the fibres treatment area between the rotor and the stator blades, preferably different from the low consistency on the refiner inlet, replacing in the recycling of some types of waste paper a very energy-intensive high-consistency dispersion system.
• the method according to the invention shall be explained in more detail on the basis of the embodiment presented in the drawing, which shows the method of including pumping separators with a conical screen and a multi-functional refiner into the waste paper recycling line, which allows waste paper stock to be fractioned during defibering and the fractions to be treated separately.
• Embodiment Waste paper with water is introduced into the tub of the pulper 1.
• the secondary pulper 2 cooperates with the pulper 1 connected to it. Rejects from the secondary pulper 2 are discharged into the drum screen 3.
• fibre pulp is collected from the131 tub 1 , which then undergoes treatment in two operations, the first of which is typically carried out in the secondary pulper 2, whereas the second operation performed on the pulp received from the secondary pulper 2 is conducted according to the invention in the pumping separator 4 with a conical screen with very small openings, of the design according to Polish Patent Application No. P.410382.
• the stock pump 10 feeds the stock to the centrifugal separator - the high- consistency cleaner H . preferably with the rotor of adjustable rotation speed automatically adapted to the stock consistency value.
• the stock is discharged to the vat 5.
• the stock from this vat preferably of 2 - 2.5 % consistency, is collected according to the invention by the pumping separator 12 with a conical screen with small- diameter openings, for example 1.0 mm, which fractionates the fibre suspension.
• the short-fibre fraction is moved by the separator 12 to the vat 13, from where the stock pump 14 transports it to the conventional selective flotation system and the washing machine that are not presented in the drawing.
• the long-fibre fraction is discharged from the pumping separator 12 to the pressure screen 15 with a conical slotted screen, for example 0.35 mm. Rejects are discharged through the pipeline 16 onto the flat shaker screen.
• the stock received from the screen 15 is directed to the compactor 17, from which it is moved through the line 18 to the high-consistency dispersion system, which is not presented on the drawing, or to the vat 19, from where the stock pump 20 introduces it preferably to a multifunctional refiner 2 of the design according to the Polish Patent Application No. P.411859.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Life Sciences & Earth Sciences (AREA)
• Wood Science & Technology (AREA)
• Paper (AREA)

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Cited By (2)

Citations (5)

• 2015
  • 2015-09-23 PL PL414125A patent/PL414125A1/pl unknown
  • 2015-09-25 WO PCT/PL2015/000148 patent/WO2017052391A1/en active Application Filing

Patent Citations (5)

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