Classifications

• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
  • D21F1/00—Wet end of machines for making continuous webs of paper
  • D21F1/66—Pulp catching, de-watering, or recovering; Re-use of pulp-water
• • 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
  • D21B1/38—Conserving the finely-divided cellulosic material
• • 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
  • D21D5/28—Tanks for storing or agitating pulp
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21G—CALENDERS; ACCESSORIES FOR PAPER-MAKING MACHINES
  • D21G9/00—Other accessories for paper-making machines
  • D21G9/0009—Paper-making control systems
  • D21G9/0018—Paper-making control systems controlling the stock preparation

Definitions

• the invention relates to an operating method for a stock preparation of a paper, tissue or board machine for producing a fibrous web, comprising at least one chest for the preparation and storage of a pulp suspension.
• Machines for producing a paper or fibrous web always include an area in which the fibrous materials from which the fibrous web is produced in the machine are processed. This area is commonly called stock preparation.
• the stock preparation is followed by the constant part of the machine, in which the fibers, which were prepared in the stock preparation to a pulp suspension, are diluted so far that a fiber suspension with about 1 to 2% solids content is formed, which then on the headbox on The molding mesh is applied and dewatered there.
• the constant part consists of a cycle in which large quantities of process water are circulated.
• process water the fibers, auxiliaries and ash particles, etc., from which the fibrous web is produced in the machine, are transported and processed in such a way that a uniform pulp suspension with a desired consistency is available in the machine headbox.
• various laid paper are provided.
• several laid paper are arranged one behind the other, in which the pulp is stored, mixed and / or treated in different concentrations and quantities.
• an anaerobic condition occurs during standstill.
• this anaerobic growth in the laid paper causes the finished product to discolor and smells bad, the probability of a web break increases many times over.
• the increased use of chemicals also leads to an undesirably high concentration of chemicals in the constant part, since not all chemicals are discharged from the material cycle with the finished paper.
• An essential object of the invention is to propose an improved, but at least alternative, batch operation / batch management, which is characterized in particular by a more stable operation.
• an operating method for a stock preparation of the type mentioned at the outset which has a measurement / control / regulation Device, wherein by means of the measuring / control / regulating device at least one property parameter of the pulp suspension is determined, and by means of the measuring / control / regulating device, at least one conditioning parameter of the pulp suspension is adjusted such that at least a quality parameter of the pulp suspension remains in at least one chest within a predetermined interval when a threshold value of at least one property parameter is reached, undershot or exceeded.
• An operating method or also batch management is understood to mean a method by which the at least one chest can be controlled or regulated in order to always provide a sufficient stock of pulp suspension with quality parameters suitable for fiber web production.
• Property parameters suitable for this purpose are preferably parameters which can be selected from the following group of property parameters: a physical parameter, such as temperature, bin fill level, suspension of the pulp suspension or degree of mixing, a chemical parameter, such as pH, gas concentrations, etc. a biological parameter, such as the presence of certain protozoa, such as bacteria or fungal spores - a biochemical parameter, such as bacteria or fungus precipitants, that grow in the pulp suspension.
• a physical parameter such as temperature, bin fill level, suspension of the pulp suspension or degree of mixing
• a chemical parameter such as pH, gas concentrations, etc.
• a biological parameter such as the presence of certain protozoa, such as bacteria or fungal spores -
• a biochemical parameter such as bacteria or fungus precipitants
• the measurement of an oxygen saturation in the pulp suspension by means of the measuring / control / regulating device is suitable as a property parameter.
• the redox potential can also be used as a meaningful property parameter or measurand.
• the selected property parameter (s) can be selected within the stock be measured at various points, in particular at the entrance / in and / or at the exit of the Bütte.
• At least one of the preparation parameters can be changed by means of the measuring / control / regulating device: a filling level in the chest, in particular if the biocide infestation is very large, the level then preferably being is lowered to reduce the amount of infested suspension. a thorough mixing of the pulp suspension, if, in particular in a Bütte, a dead area has formed. a composition of the pulp suspension.
• the composition of the fiber suspension can be changed in various ways, so biocides and / or other additives can be mixed into the pulp suspension.
• the mixing of the fiber suspension can be changed by changing the flow in the chest when changing at least one quality parameter of the pulp suspension. This is achieved in a preferred manner in that the flow in the chest is changed by means of a stirrer. This can be done for example by means of an additionally installed agitator or by Lufteinschnüffelung.
• the object is achieved by means of a device, wherein this comprises at least one chute for the preparation and storage of a pulp suspension and a measuring / control / regulating device, wherein by means of the measuring / control / regulating device at least one property parameter the Faserstoffsus- pension can be determined, and by means of the measuring / control / regulating device, at least one conditioning parameter of the pulp suspension is adaptable such that at least one quality parameter of the pulp suspension remains in at least one Bütte within a predetermined interval, if a Threshold of at least one property parameter reached, undercut or exceeded becomes.
• the measuring / control / regulating device consists of at least one measuring point, a matching device for changing the quality parameters of the suspension and an evaluation unit or control or regulating device.
• the adaptation device is a metering, stirring and / or blowing device.
• biocide use can be advantageously reduced.
• FIG. 1 shows the essential components of the wastepaper stock preparation of a paper machine.
• the waste paper is dissolved into a uniform pulp, the necessary water comes wholly or partly from the machine.
• the collection bin (s) 2 are designed so that it can be stored in their pulp for about 1 -10 hours of operation of the paper machine or that it takes 1 to 10 hours to the pulp once replaced.
• a pulper is understood as meaning a large mixing vat used in industry in the production of paper, board or tissue webs in order to further dissolve the pulp.
• the volume of the pulper 3 is between 12 and 100 m 3 .
• Inn Pulper 3 the pulp is further dissolved and diluted with the addition of process water.
• the consistency of the resulting pulp suspension in the pulper 3 is about 10 to 18%.
• Contaminants such as garbage, metal wires, sand, etc., which can not be removed beforehand, e.g. Sand, are then sorted out by means of a Schwerteilcleaners 5. Contaminants that can not be filtered out by the screen plate of Schwerteilcleaners 5 can still be removed in subsequent finer grades, pre-sorting.
• the purified pulp suspension is then pumped into the pulper Ableerbütte 6, which can stockpile a supply of also about 1-10 hours. Before the pulp suspension enters the process water cycle, the fiber fraction which is not suitable for papermaking is sorted out in a presorting 7.
• the pulp suspension is stored intermediately before it is fed to the process water of the constant part. This is done in a mixing device in which the pulp suspension is diluted with process water to a pulp suspension with about 3 to 6% solids.
• the mixing device can also be used to mix other proportions of pulps and solids of the pulp suspension.
• the machine chest 10 is the last chest before the headbox. It already belongs to the constant part 14 of the paper machine. In order to ensure a constant suspension pressure in the constant part, it is always necessary to pump at least as much pulp suspension from the mixing chest into the machine chest that it has a constant level of fill level. This is achieved by constantly pumping more fiber suspension into the machine chest from the mixing chest, as is removed from the machine chest 10. The excess portion passes through an overflow back into the mixing tank, so on the one hand, the level is always kept constant and the contents of the machine chest constantly in motion, so there is always a uniform pulp suspension under constant pressure conditions. In some, not shown, downstream of the dilution stages, a further dilution of the pulp suspension before it finally reaches the machine via the headbox.
• measuring devices are provided by means of which the formation of anaerobic states can be recognized. These can be oxygen measuring devices, redox potential measuring devices, pH measuring devices and / or temperature measuring devices. The measurement takes place either directly in the chest, or inside the chest, or in the feed or discharge of the laid paper.
• the measured property parameter (s) of the pulp suspension are processed in the measuring / control / regulating device and by means of the measuring / control / regulating device at least one conditioning parameter of the pulp suspension is adapted in such a way that at least one quality parameter Parameter of the pulp suspension remains in at least one chest within a predetermined interval, when a threshold value of at least one property parameter is reached, exceeded or exceeded.
• the situation is assessed by means of individual measurements or by combining several measurements. As soon as a condition is reached which indicates the danger of an excessive growth or the aggravation of an anaerobic condition, a further aggravation can be counteracted. For counteracting or stopping the anaerobic growth, various intervention options are available by means of which the conditioning parameters can be changed.
• a simple and effective way to stop growth is to empty the affected tub as well as the laid paper adjacent to this tub. This prevents new material from being directly re-infested. Since this is usually not so easy, especially in the machine chest is not possible at all, the quality level is only lowered and by means of a Dosiervorrich- changed the biocide dosage to stock preparation.
• the biocides can be metered into the water cycle at various points.
• the metering before and / or directly in the affected paper by means of a metering device.
• the metered addition of the biocides can be kept low if the amount of the affected suspension is low and the level is low.
• the stock preparation is operated such that the lowest level of biocidal growth, the level of the affected and the subsequent laid paper is lowered and parallel to the biocide is increased and only when the biocidal growth is stopped, the level is increased again.
• recirculation devices can be provided which change the circulation within a chest by deliberately changing the flow in the chest such that the sources of production of anaerobic growth herds, which usually arise in dead zones, are moved out of these.
• the speed of the mixing device can be changed in the Mischbütten or an additional mixing device, such as a Heileinschnüffelung be provided.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Paper (AREA)

Priority Applications (3)

Applications Claiming Priority (2)

Publications (1)

Family

ID=46940467

Family Applications (1)

Country Status (5)

Cited By (2)

Families Citing this family (3)

Citations (3)

Family Cites Families (10)

• 2011
  • 2011-09-29 DE DE201110083709 patent/DE102011083709A1/de not_active Withdrawn
• 2012
  • 2012-09-19 CN CN201280047562.0A patent/CN103842580B/zh active Active
  • 2012-09-19 EP EP12766412.6A patent/EP2761080B1/de not_active Revoked
  • 2012-09-19 EP EP14189989.8A patent/EP2851466B1/de active Active
  • 2012-09-19 ES ES12766412.6T patent/ES2628435T3/es active Active
  • 2012-09-19 WO PCT/EP2012/068417 patent/WO2013045325A1/de active Application Filing

Patent Citations (3)

Also Published As

Similar Documents

Legal Events