JP6498148B2 - How to make paper - Google Patents

Description

  The present invention relates to a paper manufacturing method for making paper from paper raw materials.

  Paper-making water systems that make paper from paper raw materials contain high concentrations of organic matter and are warm environmental conditions, so that slime (biofilm) is generated by bacteria, resulting in decreased productivity such as paper breakage, Causes problems such as deterioration of quality such as spots and defects. In addition, foaming in manufacturing processes such as papermaking also adversely affects product quality and productivity.

  Thus, the papermaking water system includes many factors that adversely affect the quality of paper. Conventionally, when the quality of paper deteriorates, the cause is specified, and the processing according to it is performed in an aqueous system, thereby suppressing a decrease in paper production efficiency. For example, Patent Document 1 discloses that when the oxidation-reduction potential is an abnormal value, the cause is identified as a microorganism and a slime inhibitor is added. Patent Document 2 discloses the degree of foaming in white water. Is abnormal, it is disclosed that the cause is identified as bubbles in white water and an antifoaming agent is added.

JP 2000-259933 A JP 2005-133240 A

  However, the conventional method is an approach that is implemented after paper quality degradation has occurred, and as described above, there are a variety of potential causes of paper quality degradation. May be required. For this reason, it has been difficult to sufficiently maintain the paper production efficiency.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a paper manufacturing method capable of improving the manufacturing efficiency of high-quality paper.

  In order to complete the present invention, the present inventors have found that by measuring a plurality of water quality parameters in parallel with the operation of the papermaking system, it is possible to quickly grasp an anomaly that may cause a decrease in paper quality. It came. Specifically, the present invention provides the following.

(1) A method for producing paper,
In a papermaking aqueous system for making paper from a paper raw material, a method comprising measuring two or more water quality parameters related to water quality in parallel with the operation of the papermaking system and performing water treatment based on the measured values.

  (2) The water quality parameters are: oxidation-reduction potential, glucose amount, organic acid amount, pH, calcium ion amount, electrical conductivity, turbidity, cation requirement, temperature, foaming degree, COD (chemical oxygen requirement) The method according to (1), which is selected from the group consisting of BOD (biochemical oxygen demand), dissolved oxygen content, starch content, residual chlorine content, and respiration rate.

  (3) The measurement of the water quality parameter includes a raw material system for producing pulp from a paper raw material, a preparation / papermaking system for preparing the pulp to make paper, a recovery system for recovering white water from the preparation / papermaking system, and the above The method according to (1) or (2), wherein the method is carried out in one or more systems selected from the group consisting of a drainage system that performs drainage treatment on a part of white water recovered in the recovery system.

  According to the present invention, by measuring a plurality of water quality parameters in parallel with the operation of the papermaking system, it is possible to quickly grasp an anomaly that may cause a decrease in paper quality, and to perform an appropriate water treatment based on that, Paper quality deterioration can be prevented or highly suppressed.

1 is a block diagram of a papermaking system in which a method according to an embodiment of the present invention is performed. It is a block diagram of the papermaking type | system | group by which the method which concerns on another embodiment of this invention is implemented. It is a graph which shows transition of the water quality parameter at the time of implementing the method concerning one comparative example. It is a graph which shows transition of the water quality parameter at the time of implementing the method concerning one example of the present invention. It is a graph which shows transition of the water quality parameter at the time of implementing the method concerning another comparative example. It is a graph which shows transition of the water quality parameter at the time of implementing the method concerning another example of the present invention. It is a graph which shows transition of the water quality parameter at the time of implementing the method which concerns on another Example (A) and comparative example (B) of this invention. It is a graph which shows transition of the water quality parameter at the time of implementing the method which concerns on another Example (A) and comparative example (B) of this invention. It is a graph which shows transition of the water quality parameter at the time of implementing the method which concerns on another Example (A) and comparative example (B) of this invention. It is a graph which shows transition of the water quality parameter at the time of implementing the method which concerns on another Example (A) and comparative example (B) of this invention. It is a graph which shows transition of the water quality parameter at the time of implementing the method which concerns on another Example (A) and comparative example (B) of this invention. It is a graph which shows transition of the water quality parameter at the time of implementing the method which concerns on another Example (A) and comparative example (B) of this invention.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram of a papermaking system 10 in which the method according to the present invention is implemented. The papermaking system 10 includes a raw material system 20, a preparation / papermaking system 30, a recovery system 40, a chemical injection system 50, and a control system 60.

  The raw material system 20 produces pulp from paper raw materials. The raw material system 20 in this embodiment has a chemical pulp tank 21, a regenerated pulp tank 22, and a broke tank 23. The chemical pulp tank 21 has chemicals such as softwood bleached kraft pulp (LBKP) and hardwood bleached kraft pulp (NBKP). The pulp and recycled pulp tank 22 contain recycled pulp such as deinked pulp (DIP), and the broke tank 23 contains broke pulp as paper raw materials. An apparatus for producing and supplying each paper raw material may be provided upstream of the chemical pulp tank 21 and the recycled pulp tank 22. That is, a digester for digesting wood chips, a device for bleaching pulp, a screen for removing foreign matter, and the like may be provided upstream of the chemical pulp tank 21, and used paper is dissolved upstream of the recycled pulp tank 22. A pulper, a floater for removing ink, a device for bleaching pulp, a screen for removing foreign matter, and the like may be provided. The broke tank 23 is supplied with broke pulp produced in the preparation / papermaking system 30 or produced in another system.

  The pulp accommodated in the chemical pulp tank 21, the recycled pulp tank 22 and the broke tank 23 is supplied to the mixing chest 24 at an appropriate ratio and mixed in the mixing chest 24. The mixed pulp is transferred to the seed box 26 after adding papermaking chemicals such as a sticky agent in the machine chest 25. The chemical pulp tank 21, the regenerated pulp tank 22, the broke tank 23, the mixing chest 24, the machine chest 25, and the seed box 26 constitute the raw material system 20 of the present invention.

  The preparation / papermaking system 30 prepares pulp and makes paper. The pulp accommodated in the seed box 26 is sequentially supplied to the screen 32 and the cleaner 33 by the pump 31 together with the white water from the white water silo 38 to be described later, where the foreign matter is removed and then supplied to the inlet 34. . The inlet 34 suppresses flocs and flow stripes by supplying pulp to the wire of the wire part 35 at an appropriate concentration, speed, and angle. The supplied pulp is dehydrated with a wire part 35 and a press part 36, and then dried with a dryer part (not shown), and then subjected to appropriate processing to produce paper.

  Water from the water tank 37 is sprinkled on the wire part 35 and the press part 36 in order to clean the wire and felt. The water dehydrated from the pulp by the wire part 35 and the press part 36 and the water after watering are received by the white water silo 38 as white water. Part of the white water received by the white water silo 38 is supplied to the pump 31 and the rest is supplied to the seal pit 41. The elements from the pump 31 to the white water silo 38 constitute the preparation / papermaking system 30 of the present invention.

  The collection system 40 collects white water from the preparation / papermaking system. The supplied white water is transferred to the recovery device 42 through the seal pit 41, and is filtered and solid-liquid separated by the recovery device 42. The filtrate is recovered into the recovered water tank 43 and stored. A part of the filtrate is further filtered, returned from the primary treated water tank 44 to the water tank 37 or discharged to the outside, and the other parts to the chemical pulp tank 21, the recycled pulp tank 22 and the broke tank 23. Returned and each reused. The seal pit 41, the recovery device 42, and the recovery water tank 43 constitute the recovery system 40 of the present invention. The primary treated water tank 44 constitutes a drainage system that performs drainage treatment on a part of white water collected by the collection system.

  Of the papermaking system 10 described above, the portion through which water circulates constitutes the aqueous system according to an embodiment of the present invention, and is a portion where slime is likely to be formed through various causes. Therefore, in the papermaking system 10, an oxidizing disinfectant is added to the aqueous system from the chemical injection device 51 of the chemical injection system 50 to suppress slime. The location where the oxidizing disinfectant is added is not particularly limited, but is preferably a portion where slime is easily formed, or an efficient portion for suppressing slime in the entire aqueous system. Also good. Specifically, in FIG. 1, from the chemical injection device 51 to the white water silo 38 of the preparation / papermaking system 30 through the addition pipe 53, to the recovery water tank of the recovery water tank 43 serving as the raw material dilution liquid through the addition pipe 55 Oxidizing disinfectant is added.

  In the embodiment shown in FIG. 2, the water derived from the primary treated water tank 44 is introduced into the wet broke tank 45, and a part of the water from the seal pit 41 is cut out of the coated paper. Then, the paper is introduced into a CB (coat broke) tank 46 for storing paper (damaged paper) in which a defect has occurred. The slurry derived from the CB tank 46 and the slurry derived from the wet broke tank 45 are transferred to the broke tank 23. The oxidizing disinfectant from the chemical injection device 51 is added to the white water silo 38 through the addition pipe 53 and to the primary treated water tank 44 through the addition pipe 55.

  Although it does not specifically limit as an oxidizing disinfectant, The compound which produces hypochlorous acid and / or hypobromite in water is preferable, for example, chlorine, chlorine dioxide, highly bleached powder, hypochlorous acid, sodium hypochlorite , Potassium hypochlorite, calcium hypochlorite, ammonium hypochlorite, magnesium hypochlorite, hypobromite, sodium hypobromite, potassium hypobromite, calcium hypobromite, hypochlorous acid Examples thereof include ammonium bromate, magnesium hypobromite, chlorinated and / or brominated hydantoins, chlorinated and / or brominated isocyanuric acid, and sodium and potassium salts thereof. In addition, it can generate hypobromite by simultaneously reacting inorganic bromides such as sodium bromide, potassium bromide, ammonium bromide and calcium bromide with oxidizing compounds such as chlorine, chlorine dioxide and ozone. Good. Moreover, you may use an organic disinfectant other than such an inorganic disinfectant. Examples of organic fungicides include 2-bromo-2-nitropropane-1,3-diol, 2,2-dibromo-2-nitro-1-ethanol, 2,2-dibromo-3-nitrilopropionamide, 1 , 4-bis (bromoacetoxy) -2-butene and the like. These oxidizing disinfectants may be used alone or in combination of two or more. The chemical injection device 51 may be an appropriate facility depending on the type of oxidizing disinfectant used.

  In the water system of the papermaking system 10, slime formation is promoted not only by microorganisms but also by pH reduction, temperature rise, etc., and there are problems such as pitch and defect generation due to calcium precipitation, paper breakage due to white water bubbles, etc. obtain. For this reason, the method of the present invention includes a step of measuring two or more water quality parameters related to water quality in parallel with the operation of the papermaking system 10 and performing water treatment based on the measured value. Thereby, it is possible to prevent or highly suppress the deterioration of the paper quality by grasping the abnormality that may cause the deterioration of the paper quality at an early stage and performing the appropriate water treatment based thereon. Note that the measurement may be performed continuously or intermittently.

  The water quality parameter is not particularly limited, and may be appropriately selected according to the circumstances of the aqueous system in which the method of the present invention is performed. Two or more selected from the group consisting of turbidity, cation requirement, temperature, degree of foaming, COD, BOD, dissolved oxygen content, starch content, residual chlorine content, and respiration rate are preferred.

  The oxidation-reduction potential is a parameter that reflects the anaerobic or aerobic state in the aqueous system. The lower the potential, the easier the slime is formed. The lower the measured redox potential value, the greater the treatment level of bactericidal (eg, addition of oxidizing bactericides) or bacteriostatic (eg, water-based cooling), and the higher the measured value, the higher the bactericidal or bacteriostatic treatment level. cut back.

  Specifically, in FIG. 1, ORP meters 63 and 65 for measuring the oxidation-reduction potential are provided in the broke tank 23 and the seed box 26, and these ORP meters 63 and 65 transmit the measured values to the control device 61 of the control system 60. Send to. The control device 61 controls the chemical injection system 50 based on the received measurement value, and adjusts the addition amount of the oxidizing disinfectant from the chemical injection device 51 to the white water silo 38 and the recovered water tank 43. In FIG. 2, ORP meters 63A, 65A, 67 for measuring the oxidation-reduction potential are provided in the seal pit 41, the wet broke tank 45, and the CB tank 46, and the control device 61 moves from the chemical injection device 51 to the white water silo 38, primary. The amount of oxidizing disinfectant added to the treated water tank 44 is adjusted. In addition, the control apparatus 61 increases / decreases the opening degree and opening time length of the valve (not shown) provided in the addition pipes 53 and 55, for example. However, the adjustment of the addition amount is not limited to such automatic control, and may be artificial control.

  Since glucose is a degradation product of starch by microorganisms, the amount of glucose reflects the degree of propagation of the microorganisms. The higher the measured value of the glucose amount, the higher the treatment level of bactericidal or bacteriostatic, and the lower the measured value, the lower the treatment level of bactericidal or bacteriostatic. By increasing the amount of glucose (starch decomposition product and nutrient source of microorganisms), microorganisms grow and decrease dissolved oxygen, and the ORP value decreases. In the case of measuring only the amount of glucose, microbial contamination cannot be grasped when glucose is consumed by microorganisms and the value is low. However, by measuring the ORP value together, microbial contamination is also observed. Can be grasped.

  Since organic acid is also a degradation product of starch by microorganisms, the amount of organic acid reflects the degree of propagation of microorganisms. The higher the measured value of the organic acid amount, the higher the level of sterilization or bacteriostatic treatment, and the lower the measured value, the lower the level of sterilization or bacteriostatic treatment. Examples of the organic acid include one or more of formic acid, acetic acid, propionic acid, butyric acid, oxalic acid, valeric acid and the like. When microorganisms decompose starch under anaerobic conditions, an organic acid is produced, and an organic acid salt is produced by combining this organic acid with calcium. Therefore, by measuring the ORP value together with the amount of organic acid, Organic acid salt pitch generation can be predicted. Moreover, since the increase in the amount of glucose and the amount of organic acid indicates the degradation of starch by microorganisms, generation of organic acid salt derived from organic acid can be predicted by measuring both.

  The pH varies depending on various factors including the production of organic acids, but the efficacy of drugs (eg, bactericides) often depends on the pH. For this reason, it is preferable to adjust the pH by adding a base or the like so that the pH falls within a predetermined preferable range depending on the drug to be used. The measured pH value in the present invention refers to the measured pH value at each time point, and is clearly different from the amount of change with time of pH as disclosed in, for example, Japanese Patent Application Laid-Open No. 2010-1000094. Based on the measured pH value, the ORP measured value having pH dependence can be appropriately corrected. For example, the ORP measurement value is higher than the true ORP value in the system to which the oxidant is added, but the true ORP value is calculated by correcting the ORP measurement value based on the pH measurement value, and an appropriate drug injection is obtained. Control can be performed. Moreover, the production | generation of organic acid is estimated from the fall of pH, and if it is judged from the ORP value that it is an anaerobic state, generation | occurrence | production of organic acid salt can be estimated. Or since pH falls with the organic acid produced | generated after starch decomposition | disassembly, calcium ion increases and generation | occurrence | production of a calcium carbonate defect can be estimated by measuring the amount of glucose or the amount of organic acids with pH.

  It is considered that calcium ions increase due to dissolution of calcium carbonate in the pulp accompanying pH reduction, and that the pitch adheres to the apparatus constituting the papermaking system 10. For this reason, the treatment level of bactericidal or bacteriostatic is increased as the measured value of the calcium ion amount is higher, and the treatment level of bactericidal or bacteriostatic is reduced as the measured value is lower. By measuring the ORP value together with the calcium ion amount, it is possible to predict a calcium salt defect due to the binding of fatty acid and calcium ion under anaerobic conditions. When the glucose of the starch degradation product increases, it shows the degradation of starch by microorganisms. Therefore, the occurrence of calcium carbonate defects after starch degradation can be predicted by measuring the amount of glucose together with the amount of calcium ions. By measuring the amount of organic acid or pH together with the amount of calcium ion, the amount of calcium ion increases through a decrease in pH due to the organic acid, and the occurrence of calcium carbonate defects can be predicted.

  The electrical conductivity reflects the amount of ionic substances in the aqueous system and is considered as a factor that affects the fixing efficiency of chemicals such as polymers on paper products. For this reason, the higher the measured value of electrical conductivity, the higher the level of sterilization or bacteriostatic treatment, and the lower the measured value, the lower the level of sterilization or bacteriostatic treatment. Although not shown in FIGS. 1 and 2, an instrument for measuring electrical conductivity is provided alongside the ORP meters 63 and 65. If the electrical conductivity increases under anaerobic conditions, starch degradation is expected. The starch adhering to the fiber is broken down, and a release of the pitch contained between the fiber and starch occurs. For this reason, this pitch can be predicted by measuring the ORP value together with the electrical conductivity. By measuring the amount of glucose, the amount of organic acid or pH, and the amount of calcium ions together with the electrical conductivity, the ionic substances increase with the decrease in pH due to the organic acid generated after starch degradation, and the calcium carbonate defect and the inorganic substance defect It can be predicted that it will occur.

  Turbidity reflects the amount of a component that imparts turbidity (for example, an anionic trash component) and affects the efficacy of a drug (for example, a bactericidal agent). For this reason, the treatment level of sterilization or bacteriostasis and coagulation (for example, addition of a coagulant) is increased as the measured value of turbidity is higher, and the treatment level of sterilization or bacteriostasis is decreased as the measurement value is lower. If turbidity increases under anaerobic conditions, starch degradation is expected. The starch adhering to the fiber is broken down, and a release of the pitch contained between the fiber and starch occurs. For this reason, this pitch can be predicted by measuring the ORP value together with turbidity. Since the amount of glucose and turbidity increase due to degradation of starch by microorganisms, slime defects due to microbial propagation through degradation of starch can be predicted by measuring the amount of glucose together with turbidity. Similarly, by measuring the amount of organic acid together with turbidity, it is possible to predict slime defects through microbial growth due to starch degradation. By measuring the pH together with the turbidity, it is possible to predict the occurrence of pitch defects due to the decomposition of the starch adhering to the fibers and the release of the pitch contained between the fibers and the starch. By measuring the amount of calcium ions or the electrical conductivity along with turbidity, it is possible to predict the occurrence of defects of inorganic substances such as calcium through the production of organic acids by starch degradation.

  The required amount of cation reflects the possibility of anion trash and affects the efficacy and the like of a drug (for example, a bactericidal agent). For this reason, the treatment level of bactericidal or bacteriostatic or coagulation (for example, addition of a coagulant) is increased as the measured value of the cation requirement amount is higher, and the treatment level of bactericidal or bacteriostatic is reduced as the measured value is lower. If the cation requirement is increased under anaerobic conditions, starch degradation is expected. The starch adhering to the fiber is broken down, and a release of the pitch contained between the fiber and starch occurs. For this reason, this pitch can be predicted by measuring the ORP value together with the required cation amount. If the cation requirement increases when the amount of glucose or organic acid increases, starch degradation is expected, so by measuring the glucose amount, organic acid amount or pH together with the cation requirement, the occurrence of pitch defects can be prevented. Can be predicted. By measuring the amount of calcium ions, electrical conductivity, or turbidity together with the required amount of cation, it is possible to predict the occurrence of defects of inorganic substances such as calcium through the production of organic acids due to starch degradation.

  The temperature varies depending on various factors including the propagation of microorganisms, but the efficacy of drugs (for example, bactericides and antifoaming agents) often depends on the temperature. For this reason, it is preferable to adjust temperature so that temperature may fall in a predetermined preferable range according to the chemical | medical agent to be used. Even when the ORP value decreases due to mixing of a reducing agent or the like, microbial growth can be predicted by measuring the temperature together. Even when the amount of glucose varies due to hydrogen peroxide contamination, microbial growth can be predicted by measuring the temperature together.

  When bubbles or agglomerates formed from bubbles are mixed into a product, it is regarded as a product defect. For this reason, the higher the measured value of the degree of foaming, the higher the processing level of antifoam (for example, addition of antifoaming agent), and the lower the measured value, the processing level of antifoaming (for example, addition of antifoaming agent). Reduce. The degree of foaming is typically measured by foaming in the white water silo 38. Due to the increase in pH, the amount of foaming increases and foam defects occur. For this reason, by measuring foaming with pH, addition of an antifoamer can be optimized and generation | occurrence | production of the fault by excessive addition can also be suppressed. By measuring the amount of calcium ions together with the amount of foaming, inorganic defects can be predicted. In a system with many bubbles, it is difficult to grasp the unfixed portion of the filler only by the amount of foaming, but it is possible to grasp the unfixed filler by measuring the electrical conductivity together with the amount of foaming. By measuring the amount of foaming together with turbidity, the addition of an antifoaming agent can be optimized, and the occurrence of defects due to excessive addition of chemicals can also be suppressed. In a system containing a large amount of air bubbles, it is impossible to accurately determine poor fixing of internal chemicals, but microbial growth can be predicted by measuring the required amount of cation or the temperature together with the amount of foaming.

  COD and BOD reflect the anaerobic nature of the water system depending on the amount of deinked pulp (DIP) used, and affect the load level of the drainage system. The lower the measured value of COD or BOD, the higher the treatment level of bactericidal or bacteriostatic, and the lower the measured value, the lower the treatment level of bactericidal or bacteriostatic. In addition, COD or BOD tends to increase if the fixing efficiency of polymer or starch to paper deteriorates. Based on the measured value of COD or BOD, grasp the transition of fixing efficiency of polymer or starch to paper. be able to. An increase in COD and BOD under anaerobic conditions suggests starch degradation and drug colonization inhibition. For this reason, generation | occurrence | production of the fault derived from a chemical | medical agent can be estimated by measuring ORP value, the amount of glucose, or the amount of organic acids with a COD and BOD value. By measuring pH together with COD or BOD, it is possible to improve the yield of chemicals and to suppress defects caused by excess chemicals. An increase in calcium ions closes the anion group of the drug, leading to a decrease in its effect, but in a system with a large amount of filler, measuring the amount of COD or BOD together with the calcium ion amount or electrical conductivity, predicts unfixed drug be able to. In addition, in an acidic system with high electric conductivity, it is difficult to grasp the unfixed amount of the drug only by the electric conductivity, but it is also possible to predict unfixed of the drug by measuring COD or BOD. . Even in a system where it is difficult to measure turbidity such as high-concentration pulp, it is possible to predict unfixed chemicals by measuring COD or BOD together with turbidity.

  The amount of dissolved oxygen reflects the amount of oxygen consumed by the microorganism. The treatment level of sterilization or bacteriostasis is increased as the measured value of the dissolved oxygen amount is lower, and the treatment level of sterilization or bacteriostasis is decreased as the measurement value is higher. An increase in glucose and a decrease in dissolved oxygen indicate starch degradation by microorganisms under anaerobic conditions. By measuring the amount of glucose together with dissolved oxygen, microbial growth due to starch degradation is expected, and slime defects can be predicted. It becomes. In a system that easily involves bubbles in water, it is difficult to predict the growth of microorganisms using dissolved oxygen alone, but by measuring the amount of organic acid, pH, calcium ion, electrical conductivity, or turbidity, Breeding can be predicted. By measuring the amount of foaming together with the temperature, the addition of an antifoaming agent can be optimized and the occurrence of defects due to excessive chemicals can also be suppressed.

  Although starch is one of the components of paper, it is degraded by enzymes secreted by microorganisms, so the amount of starch reflects the degree of propagation of microorganisms. The lower the measured amount of starch, the higher the level of sterilization or bacteriostatic treatment, and the higher the measured value, the lower the level of sterilization or bacteriostatic treatment. When measuring only the amount of starch, it is difficult to grasp the microbial contamination when starch and glucose are consumed by microorganisms, but by measuring the ORP value, the microbial contamination in such a case can also be predicted. be able to. By measuring the amount of starch together with the amount of glucose, microbial growth can be predicted even when the amount of glucose varies due to hydrogen peroxide contamination. By measuring the amount of starch together with the amount of organic acid or pH, microbial growth can be predicted even in a system to which a pH adjuster is added. By measuring the amount of starch together with the amount of calcium ions and electrical conductivity, slime defects derived from microorganisms can be predicted. By measuring the amount of starch together with dissolved oxygen, it is possible to predict the occurrence of drug-derived defects.

  The amount of residual chlorine reflects the amount of fungicide that inhibits the growth of microorganisms. When the amount of residual chlorine decreases, the growth of microorganisms is expected, so the level of sterilization or bacteriostatic treatment is increased. Even when the ORP value becomes high due to the mixing of the oxidant and it is difficult to predict the propagation of microorganisms, the propagation of microorganisms can be predicted by measuring the residual chlorine amount. Even when the amount of glucose varies due to hydrogen peroxide contamination, microbial growth can be predicted by measuring the amount of residual chlorine. Even in a system to which a pH adjuster is added, microbial growth can be predicted by measuring the amount of residual chlorine together with the amount of organic acid or pH. In a system with many fillers, it is difficult to grasp microbial growth only by measuring the amount of calcium ions, but microbial growth can be predicted by measuring the amount of residual chlorine. In a system in which industrial water is mixed, it is difficult to grasp the increase in electrical conductivity, but microbial growth can be predicted by measuring the amount of residual chlorine together with the electrical conductivity. Even when it is difficult to measure turbidity such as high-concentration pulp, microbial growth can be predicted by measuring the residual chlorine amount together with the turbidity. In a system containing a lot of bubbles, it is difficult to predict the growth of microorganisms by measuring only the amount of dissolved oxygen, but the growth of microorganisms can be predicted by measuring the amount of residual chlorine. In a system to which starch is added, it is difficult to predict microbial growth by measuring only the amount of starch, but microbial growth can be predicted by measuring the amount of residual chlorine.

  The respiration rate reflects the amount of microorganisms. As the respiration rate increases, the growth of microorganisms is expected, so the level of disinfection or bacteriostatic treatment is increased. Even when an oxidizing agent and a reducing agent are added and the ORP value fluctuates, microbial growth can be predicted by measuring the respiratory rate together with the ORP value. Even when the amount of glucose fluctuates due to hydrogen peroxide contamination, microbial growth can be predicted by measuring the respiration rate together. Even in a system to which a pH adjuster is added, microbial growth can be predicted by measuring the respiration rate together with the amount of organic acid or pH. In a system in which bubbles are mixed in water, the measurement accuracy of the respiration rate may be lowered, but microbial growth can be predicted by measuring the amount of calcium ions. In a system in which industrial water is mixed, it is difficult to grasp the increase in electrical conductivity, but microbial growth can be predicted by measuring the respiration rate together with the electrical conductivity. Even when it is difficult to measure turbidity of high-concentration pulp or the like, microbial growth can be predicted by measuring the respiration rate together with turbidity. In a system containing a lot of bubbles, it is difficult to predict microbial growth by measuring only the dissolved oxygen amount, but microbial growth can be predicted by measuring the respiratory rate together. In a system to which starch is added, it is difficult to predict microbial growth by measuring only the amount of starch, but microbial growth can be predicted by measuring the respiration rate together.

  In addition, since measurement of each water quality parameter and water treatment should just be performed in accordance with a conventionally well-known method, detailed description is abbreviate | omitted.

  The location where the water quality parameter is measured is not particularly limited, but it is preferably 1 or more types selected from the group consisting of a raw material system, a preparation / papermaking system, a recovery system, and a drainage system, more preferably 2 More than a seed system. Thereby, since the water quality of the whole water system is grasped | ascertained, a paper quality fall can be suppressed more reliably. However, the present invention is not limited to this, and the number of measurement points may be one or more than one in the same system.

  The measured value of the water quality parameter is not particularly limited, but can be browsed at a remote location via the Internet through a server, and remote control based on the received measured value may be performed. Further, in a remote place, there may be means for outputting the measurement value, the mode of water treatment (for example, the amount of added bactericidal agent), and the result (for example, presence or absence of paper break).

<Example 1>
Using the papermaking system 10 shown in FIG. 1, the slime suppression method according to the examples and comparative examples was carried out. In addition, an Example and a comparative example were common about the following conditions, and differed in the timing of the measurement of an oxidation-reduction potential and electrical conductivity, and the addition of an oxidizing disinfectant.
Paper raw materials: LBKP, DIP and broke pulp Oxidizing disinfectant: Liquid prepared by mixing 1.3% by mass ammonium bromide aqueous solution and 2.0% by mass sodium hypochlorite aqueous solution immediately before addition: Broke tank 23, white water Silo 38

  That is, in the comparative example, the oxidizing disinfectant is periodically added at a frequency of once every hour, and in the example, the oxidation-reduction potential and the electrical conductivity are measured at a frequency of once every 15 minutes. The amount of the oxidizing bactericide added was adjusted according to the increase / decrease. FIG. 3 shows changes in the oxidation-reduction potential and electrical conductivity in the seed box 26 in the comparative example, and FIG. 4 shows changes in the oxidation-reduction potential and electrical conductivity in the seed box 26 in the example.

  As shown in FIG. 3, in the comparative example, when the blending amount of DIP is increased, the oxidation-reduction potential is rapidly decreased, the electric conductivity is rapidly increased, and the paper breaks are frequently generated. On the other hand, in the example, as shown in FIG. 4, the oxidation-reduction potential and the electrical conductivity followed a substantially constant transition regardless of the change in the amount of DIP, and no paper break was observed. In the examples, the amount of the oxidizing bactericide used was 20% smaller than that of the comparative example.

<Example 2>
Using the papermaking system 10A shown in FIG. 2, the slime suppression method according to the examples and comparative examples was carried out. In addition, an Example and a comparative example were common about the following conditions, and differed in the timing of the measurement of an oxidation-reduction potential and electrical conductivity, and the addition of an oxidizing disinfectant.
Paper raw materials: LBKP, DIP and broke pulp Oxidizing disinfectant: Liquid prepared by mixing 1.3 mass% ammonium bromide aqueous solution and 2.0 mass% sodium hypochlorite aqueous solution immediately before addition: White water silo 38, primary Treated water tank 44

  That is, in the comparative example, the oxidizing disinfectant is periodically added at a frequency of once every 4 hours, and in the example, in addition to the addition at a frequency of once every 4 hours, the oxidation-reduction potential in the wet broke tank 45 and The amount of the oxidizing bactericide added was adjusted according to the increase or decrease in the measured electric conductivity. FIG. 5 shows changes in the oxidation-reduction potential and electrical conductivity in the seal pit 41, the wet broke tank 45 and the CB tank 46 in the comparative example, and the oxidation-reduction in the seal pit 41, the wet broke tank 45 and the CB tank 46 in the embodiment. The transition of the electric potential and the electric conductivity in the wet broke tank 45 is shown in FIG.

  In the comparative example, a large amount of coat broke is stored in the wet broke tank 45 and is easily spoiled. As shown in FIG. 5, the oxidation-reduction potential and the electrical conductivity change abruptly, resulting in paper defects. It was. On the other hand, in the example, as shown in FIG. 6, the oxidation-reduction potential and the electrical conductivity followed a substantially constant transition, and no paper defects were observed.

<Example 3>
Using the papermaking system shown in FIG. 2, the slime suppression method according to the examples and comparative examples was carried out. In addition, an Example and a comparative example are common about the following conditions, and differ in the timing of two measurements among oxidation-reduction potential, electrical conductivity, foam height, and broke turbidity, and the addition timing of an oxidizing disinfectant. It was.
Paper raw materials: LBKP, DIP and broke pulp Oxidizing disinfectant: Liquid prepared by mixing 1.3% by mass ammonium bromide aqueous solution and 2.0% by mass sodium hypochlorite aqueous solution immediately before the addition. Wet broke tank 45, CB tank 46

  First, an example was performed over 4 days, and then a comparative example was performed over 4 days. In the comparative example, the oxidizing disinfectant is periodically added at a frequency of once every 4 hours. In the example, in addition to the addition at a frequency of once every 4 hours, the oxidation-reduction potential (ORP meter 67 in the CB tank 46). The amount of the oxidizing disinfectant added is adjusted according to the increase / decrease of the measured value of the electrical conductivity at the seal pit 41, the height of the foam at the seal pit 41, and the turbidity measured at the broke tank 23. did. Specifically, the threshold values are 250 mV for the redox potential, 150 mS / m for the electrical conductivity, 8 cm for the bubble height, and 300 NTU for the broke turbidity, and when both of the two measured values exceed the threshold (the electrical conductivity Only when the above threshold values were exceeded for foam height and broke turbidity, and when the oxidation-reduction potential was below the above threshold values), the addition amount of the oxidizing disinfectant was increased until both did not exceed the threshold values. 7-12, (A) shows an Example and (B) shows transition of each water quality parameter in a comparative example. As a result, in the comparative example, 26 paper breaks occurred in 4 days, whereas in the example, only 8 paper breaks occurred in 4 days.

10 Papermaking 20 Raw Material 21 Chemical Pulp Tank 22 Recycled Pulp Tank 23 Broke Tank 24 Mixing Chest 25 Machine Chest 26 Seed Box 30 Preparation / Papermaking 31 Pump 32 Screen 33 Cleaner 34 Inlet 35 Wire Part 36 Press Part 37 Water Tank 38 White water silo 40 Recovery system 41 Seal pit 42 Recovery device 43 Recovery water tank 44 Primary treated water tank 45 Wet broke tank 46 CB tank 50 Chemical injection system 51 Chemical injection device 53, 55 Addition pipe 60 Control system 61 Control devices 63, 65, 67 ORP meter

Claims (2)

A method for continuously producing paper,
In a papermaking aqueous system for making paper from a paper raw material, in parallel with the operation of the papermaking system, two or more of the plurality of systems constituting the aqueous system and the same system are involved in water quality 2 measuring the above water quality parameters, its has a step of performing water treatment based on these measured values,
The two or more water quality parameters are:
Electrical conductivity,
At least one parameter selected from the group consisting of glucose amount, organic acid amount, pH, and calcium ion amount;
Only including,
In the water treatment, the occurrence of calcium carbonate defects or inorganic defects is predicted from the measured values of the two or more water quality parameters, and the treatment level of sterilization or bacteriostasis is determined and determined in consideration of the predicted results. Said method , which is a treatment for sterilizing or bacteriostatically treating . The one or more systems are a raw material system for producing pulp from paper raw materials, a preparation / papermaking system for preparing the pulp and making paper, a recovery system for recovering white water from the preparation / papermaking system, and the recovery system in for some of the recovered white water selected from the group consisting of drainage system for performing waste water treatment method of claim 1, wherein.

Images