JP4595467B2 - Concentration control method for cleaning agent and cleaning water - Google Patents

Description

  The present invention relates to a cleaning agent used in a papermaking process, and more particularly, to a cleaning agent for a papermaking process for cleaning felt or the like used in a papermaking process, and a concentration management method for cleaning water containing the cleaning agent.

  The paper making process includes a wire process for obtaining wet paper formed by making paper suspended in white water and a press process for press dehydrating the wet paper. In the wire process, the wet paper that has been made is placed on an annular belt called a wire (or a papermaking net), and the wet paper is sent to the press process while removing water from the wet paper by moving the annular belt with a roll. In the pressing step, wet paper is placed on a felt annular belt, and press dewatering is performed with the wet paper sandwiched between two opposing rolls.

  The wires, felts, and rolls used in the papermaking process are clogged due to adhesion of fine fibers derived from pulp and aluminum hydroxide derived from papermaking additives. When the felt or the like is clogged, there arises a problem that the dewaterability of the wet paper is deteriorated and the dewatering becomes insufficient, or the wet paper cannot be dehydrated uniformly.

  For this reason, conventionally, there has been proposed a method in which felt or the like is kept clean by spraying water, in which a chemical having a cleaning effect or a dirt adhesion preventing effect, is dissolved, onto the felt or the like. As chemicals used to keep felts and the like clean, cleaning agents that remove dirt adhered to felts, pitch control agents that prevent dirt from adhering to felts, etc. are known, for example Patent Document 1 discloses a method of adding a polymer having an acrylamide unit to washing water for washing felt.

  By the way, the wire and felt which constitute the paper making process described above are driven by a plurality of rolls, and there are a large number of cleaning points to be cleaned with the cleaning water to which the above chemicals are added. For this reason, it is difficult to install facilities such as tanks for storing water necessary for the preparation of cleaning water at each cleaning location, and paper mills have conventionally installed a small number of tanks for storing water and a large number of washings through piping. While supplying water from the said tank to the location, the washing | cleaning water was prepared by providing the addition apparatus of the cleaning agent in the middle of piping. Thus, in a cleaning facility with a small number of tanks installed and a complicated piping configuration, each pipe is not provided with a flow meter, and the amount of cleaning water used at each cleaning point cannot be accurately grasped. For this reason, there is a problem that the concentration of the cleaning agent contained in the cleaning water fluctuates when the amount of water supplied from the tank fluctuates.

In particular, since the felt needs to be kept clean, the cleaning water for cleaning the felt is not used as a cleaning water in principle, and cleaning water prepared using clean water such as industrial water is used. In this way, with regard to cleaning water that is not supposed to be recycled, unlike the white water for pulp suspension that is supposed to be recycled, the concentration management of the cleaning agent is not conceived, and the concentration management of the cleaning agent is not controlled. Even if it is going to be performed, there is no circulation path for the cleaning water to circulate, and it takes time to measure the concentration of the cleaning component itself, so it is difficult to control the concentration of the cleaning agent in the cleaning water. For this reason, the problem of poor cleaning caused by the concentration of the cleaning agent contained in the cleaning water being unstable has arisen.
Japanese Patent Laid-Open No. 11-81175

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a cleaning agent that prevents the concentration fluctuation of cleaning components in cleaning water that removes dirt such as felt and exhibits a stable cleaning effect. The present invention also provides a concentration management method for cleaning water that can easily and quickly grasp the concentration of cleaning components contained in cleaning water such as felt and maintain the concentration of cleaning components contained in cleaning water within a predetermined range. The purpose is to provide.

  In the present invention, the concentration of the cleaning component in the cleaning water is managed by adding a tracer substance contained in the cleaning agent in a predetermined ratio to the cleaning component and tracing the concentration of the cleaning component. Specifically, the present invention provides the following.

  (1) A cleaning agent contained in cleaning water for cleaning a paper machine, a cleaning component for removing paper stains adhering to the paper machine, and a tracer substance that traces the concentration of the cleaning component contained in the cleaning water And a cleaning agent for a papermaking process.

  Here, the “cleaning component” has an action of removing at least a part of organic or inorganic stains (collectively referred to as “papermaking stains”) adhering to the felt or wire of the papermaking machine in the papermaking process. One or more substances are meant. As the cleaning component, any substance can be selected according to the type of papermaking stains attached to the felt or the like to be cleaned.

  For example, a surfactant is mentioned as a cleaning component that removes organic stains derived from resins contained in wood and paper additives. In addition, as a cleaning component for removing inorganic stains derived from a sulfuric acid band used for fixing a sizing agent in a papermaking process in which acidic papermaking is performed, there are inorganic acids or organic acids. Examples of surfactants include anionic surfactants such as alkylbenzene sulfonates, higher alcohol sulfates, α-olefin sulfonates, and dialkyl sulfosuccinates. Nonionic surfactants include alkylenes. Examples include oxide adducts and polyalkylene oxides.

  “Tracer substance” means a substance that is chemically stable and does not substantially react with the cleaning component and papermaking soil, and is contained in the cleaning agent in a predetermined ratio with respect to the cleaning component. And have a correlation. Examples of the tracer substance include a fluorescent tracer that emits fluorescence, an ion tracer, and the like, and any substance that does not substantially react with cleaning components and dissolved salts contained in the cleaning water and is chemically stable can be used without particular limitation.

  The cleaning agent according to the present invention is used by being dissolved in water and sprayed onto a paper machine as cleaning water, and the tracer substance has a concentration in the cleaning water of 0.1 to 100 mg / L, particularly 1 to 10 mg / L. It is preferable to be mixed with the cleaning agent so as to be L. The tracer substance is contained in the cleaning agent so as to correlate with the content of the cleaning component, and the tracer substance is preferably blended in an amount of 0.1 to 10% by weight, particularly 0.5 to 2% by weight based on the cleaning agent. The cleaning agent is usually used after being dissolved in water so as to have a concentration of 10 to 1000 mg / L. At this time, the tracer substance contained in the cleaning water falls within the above range.

  As water for dissolving the cleaning agent (hereinafter referred to as “solvent water”), it is preferable to use fresh water. Here, “fresh water” means water that is not recycled as cleaning water. On the other hand, the water discharged from the papermaking process and recycled as white water in a state where it is not purified is called “circulated water”. Fresh water includes city water, lake water, river water, and groundwater used as industrial water, and even wastewater discharged from the papermaking process is used as industrial water after purification treatment such as coagulation and filtration. Water purified to purity (hereinafter referred to as “treated water”) shall be included in the fresh water.

  The cleaning agent according to the present invention may contain substances other than cleaning components and tracer substances. Examples of other components contained in the cleaning agent include a pitch control agent, a scale inhibitor, and a slime control agent.

  In the present invention, since the tracer substance is contained in the cleaning agent, the concentration of the cleaning component can be grasped easily and quickly by measuring the concentration of the tracer substance. For this reason, the density | concentration of the washing | cleaning component contained in the water for washing | cleaning can be easily maintained in an appropriate range, without providing a flowmeter in each place of piping which connects the tank which stores solvent water, and a washing location. Therefore, it is possible to simplify the cleaning equipment in the papermaking process and supply cleaning water that exhibits a stable cleaning effect to the cleaning portion.

  (2) The said tracer substance is a cleaning agent for papermaking processes as described in (1) which is an ion tracer.

  Since the ion tracer does not color the solvent water and is less likely to adhere to the felt or the like and deteriorate the felt or the like, it can be suitably used in the present invention. The ion tracer can be contained in the cleaning agent as a water-soluble salt, and dissociates the ions by dissolving the cleaning agent in water. Therefore, the colorimetric method, titration method, ion chromatography method, atomic absorption method, or It can be easily measured by various ion concentration measuring devices using an ion electrode method or the like.

  (3) The said ion tracer is a cleaning agent for papermaking processes as described in (2) which is 1 or more types chosen from lithium salt, potassium salt, magnesium salt, phosphate, and nitrate.

  Lithium ions, potassium ions, magnesium ions, phosphate ions, and nitrate ions are less likely to affect the cleaning effect of the cleaning agent and are easy to measure. For this reason, these ions can be used particularly suitably as an ion tracer. In particular, lithium ions are preferable because they are not substantially contained in fresh water and can be easily and rapidly measured with an ion electrode.

  Examples of the lithium salt contained in the cleaning agent include lithium chloride and lithium hydroxide. Examples of potassium salts include potassium chloride and potassium hydroxide. Magnesium salts include magnesium sulfate. Examples of the phosphate include sodium phosphate. Examples of nitrate include sodium nitrate.

  (4) A concentration control method for cleaning water for cleaning a paper machine, wherein the cleaning water includes a cleaning component for removing paper stains attached to the paper machine, and a concentration of the cleaning component contained in the cleaning water. And a tracer substance to be traced, and a concentration management method for cleaning water that adjusts the concentration of the cleaning component by measuring the concentration of the tracer substance.

  According to the present invention, the concentration of the tracer substance in the cleaning water in which the cleaning agent containing the tracer substance is dissolved is measured periodically or continuously, and the concentration of the cleaning agent in the cleaning water is grasped based on the measured value. . Specifically, the correlation between the cleaning agent and the tracer substance is obtained in advance by a preliminary experiment or the like, and the concentration is adjusted by calculating the concentration of the cleaning agent based on the measured value of the tracer substance concentration in the cleaning water. .

  As a method for adjusting the concentration of the cleaning agent, there are a method for adjusting the flow rate of the solvent water supplied to the nozzle for spraying the cleaning water from the tank for storing the solvent water, a method for adjusting the supply amount of the cleaning agent, and the like. is there. Specifically, the rotational speed of the solvent water supply pump provided in the middle of the pipe connecting the tank and the nozzle or the pump for supplying the cleaning agent may be changed.

  (5) The concentration management method for cleaning water according to (4), wherein the tracer substance is at least one selected from lithium salt, potassium salt, magnesium salt, phosphate, and nitrate.

  Lithium ions and potassium ions can be measured easily and quickly with an ion electrode, magnesium ions with a hardness meter, and phosphate ions and nitrate ions with a phosphonic acid measurement kit using a titration method. For this reason, if the said substance is used as a tracer substance, the washing | cleaning component density | concentration can be measured easily and rapidly and the density | concentration management of a washing | cleaning component can be performed.

  According to the present invention, it is possible to easily and quickly grasp the cleaning component concentration of cleaning water for cleaning a paper machine including a wire or felt used in a paper manufacturing process, and adjust the cleaning component concentration to be within a predetermined range. . For this reason, the washing effect of washing water can be stabilized. In addition, since excessive use of cleaning agents and solvent water can be prevented, the wastewater treatment load discharged from paper machine cleaning can be reduced, and when wastewater is collected and recycled as white water, etc. The influence on the additive for papermaking, such as a pitch control agent added to water, can be prevented.

  Hereinafter, the present invention will be described in detail with reference to the drawings. Hereinafter, the same members are denoted by the same reference numerals, and the description is simplified or omitted.

  FIG. 1 is a schematic diagram of a paper machine 1. The paper making machine 1 includes a wire part 10 that obtains a wet paper 5 containing moisture by making paper made of pulp suspended in white water, and a press part 20 that dehydrates the wet paper 5.

  The wire part 10 includes a wire 11 that is a mesh-like annular belt, and a plurality of cylindrical first rolls 12. Although the size of the plurality of first rolls 12 is not necessarily the same, the surface of each of the first rolls 12 has a mesh shape like the wire 11. Further, a driving device (not shown) such as a motor is connected to each first roll 12, and the wire 11 is moved in the direction of the press part 20 by rotating the first roll 12 by the driving device.

  The press part 20 includes a felt 21 that is an annular belt made of felt, a plurality of cylindrical second rolls 22 that move the felt 21, a pair of opposing dewatering rolls 23 that press dehydrate with the wet paper 5 interposed therebetween, It consists of The surfaces of the second roll 22 and the dewatering roll 23 are both covered with felt. One of the dewatering rolls 23 is an outer roll 23 </ b> A provided outside the annular felt 21, and the other is an inner roll 23 </ b> B provided inside the felt 21.

  A driving device (not shown) such as a motor is connected to each second roll 22, and the felt 21 is moved in a direction opposite to the wire part 10 by rotating the second roll 22 by the driving device. Further, a driving device (not shown) such as a motor is connected to the dewatering roll 23, and the dewatering roll 23 is rotated so that the wet paper 5 sandwiched between the outer roll 23A and the inner roll 23B is pressed. The paper base 6 is obtained by dehydration. The paper base 6 is sent to a dry part (not shown) and dried to obtain a paper product.

  The papermaking machine 1 is provided with a cleaning device 13 for cleaning the wire 11 and the felt 21. The cleaning device 13 includes a plurality of wire nozzles 111, a plurality of felt nozzles 112, and a tank 15 that stores solvent water. The wire nozzle 111 and the tank 15 are connected by a branched first pipe 121, and the felt nozzle 112 and the tank 15 are connected by a branched second pipe 122. In the middle of the first pipe 121, there are provided a first chemical injector 131 for supplying a cleaning agent for wire cleaning to the first pipe 121 and a first pump 141 for sending the solvent water in the tank 15 to the wire nozzle 111. . Similarly, in the middle of the second pipe 122, a second chemical injector 132 that supplies a cleaning agent for felt cleaning to the second pipe 122 and a second pump 142 that sends solvent water to the felt nozzle 112 are provided.

  The cleaning agent for wire cleaning supplied from the first chemical injector 131 to the first pipe 121 is mixed with the solvent water supplied from the tank 15, and the obtained cleaning water is supplied from the wire nozzle 111 to the wire 11 and the first water. Sprayed onto the roll 12. Similarly, the cleaning agent for felt cleaning supplied from the second chemical injector 132 to the second pipe 122 is mixed with the solvent water supplied from the tank 15, and the resulting cleaning water is fed from the felt nozzle 112 to the felt 21. And sprayed onto the second roll 22. The wire 11 and the like are cleaned with these cleaning agents to remove paper stains attached to the wire 11 and the like.

  In the present invention, the cleaning agent and the tracer substance are included in the cleaning agent supplied from the first and second drug injectors 131 and 132. Then, the concentration of the tracer substance contained in the cleaning water sprayed from the wire nozzle 111 or the felt nozzle 112 is measured using the tracer measuring device 151. The tracer measuring device 151 can be appropriately selected according to the type of the tracer substance. For example, when the cleaning agent contains lithium ions as the tracer substance, an ion electrode can be used.

  The concentration of the tracer substance is preferably measured for the cleaning water ejected from each of the plurality of wire nozzles 111 and the felt nozzle 112, but the tracer is used for the cleaning water ejected from some of the wire nozzles 111 or the felt nozzles 112. The concentration measurement of the substance can be omitted. The tracer measuring device 151 is preferably installed in the vicinity of the outlets of the plurality of wire nozzles 111 and the felt nozzle 112 so that the concentration of the tracer substance is automatically measured. The administrator of the papermaking machine 1 may collect the cleaning water and measure the concentration of the tracer material manually without providing it in the vicinity.

  In the present invention, the supply amount of the cleaning agent from the first chemical injector 131 and the second chemical injector 132 is set to a constant amount, while the first pump 141 and the second pump 142 can control the rotation speed. It is configured to be able to. Therefore, when the concentration of the cleaning component calculated from the concentration of the tracer substance in the cleaning water is out of the predetermined range, the concentration of the cleaning component is adjusted by controlling the outputs of these pumps 141 and 142.

  Specifically, the concentration of the tracer substance contained in the cleaning water for wire cleaning sprayed from the wire nozzle 111 is measured, and when the measured value falls below a predetermined range, the rotational speed of the first pump 141 is decreased. Reduce the amount of solvent water supplied. Similarly, the concentration of the tracer substance contained in the cleaning water for felt cleaning sprayed from the felt nozzle 112 is measured, and when the measured value falls below a predetermined range, the rotational speed of the second pump 142 is decreased. On the other hand, when the concentration of the tracer substance for the cleaning water is high, the rotation speed of the first pump 141 or the second pump 142 is increased to adjust the concentration.

  In addition, a pump (not shown) provided in a supply passage 161 for supplying a cleaning agent from the first chemical injector 131 to the first pipe 121 is configured to be capable of adjusting the output. You may comprise the pump (not shown) provided in the supply path 162 which supplies a cleaning agent to 2 piping 122 so that output adjustment is possible. By configuring the supply amount of both cleaning agent and solvent water to be controllable, the cleaning agent supply amount is lowered when the cleaning component concentration is high, and the solvent water supply amount is lowered and cleaning is performed when the cleaning agent concentration is low. The cleaning component concentration of water can be maintained within a predetermined range, and wasteful consumption of the cleaning agent and solvent water can be prevented.

  As the cleaning agent used in the present invention, the cleaning agent for cleaning the wire part 10 includes a cationic quaternary polyamine such as an alkylamine epichlorohydrin condensate as a cleaning component, a melamine resin such as a methylolmelamic acid colloid, and the like, and a tracer substance. And detergents containing water-soluble salts. Examples of water-soluble salts that can be used as the tracer substance include lithium chloride, potassium chloride, and orthophosphoric acid.

  Examples of the cleaning agent for cleaning the press part 20 include a cleaning agent containing a polyoxyalkylene aliphatic amine, a polyoxyethylene-polyoxypropylene copolymer or the like as a cleaning component, and a water-soluble salt as a tracer substance. Examples of water-soluble salts used as the tracer substance include lithium chloride, potassium chloride, and orthophosphoric acid.

  The cleaning agent may be supplied as a stock solution, or is preferably supplied from the drug injectors 131 and 132 to the pipes 121 and 122 as a solution obtained by diluting the stock solution. The cleaning agent preferably has a cleaning component concentration of 5 to 50% by weight and a tracer substance concentration of 0.1 to 10%, and preferably about 30 to 70 ° C. in order to enhance the cleaning effect.

  In the present invention, the concentration of the cleaning component contained in the cleaning water is quickly and appropriately controlled by including a tracer substance that can be measured easily and quickly in the cleaning agent. This does not exclude the management of water concentration.

[Example 1]
Examples will be described below. As Example 1, the felt part 20 of the papermaking machine 1 was cleaned using a cleaning agent containing 1% by weight of lithium chloride as a lithium ion source as a tracer substance. In the present embodiment, the pump that supplies the cleaning agent to the second pipe 122 is also configured to be able to adjust the rotational speed. The cleaning agent contained 8% by weight of polyoxystearylamine as a cleaning component, and the stock solution was supplied from the second chemical injector 132 to the second pipe 122. Cleaning water was prepared by supplying clean water (city water) as solvent water from the tank 15 and adding the cleaning agent. Assuming that city water is supplied from the tank to the felt shower at a flow rate of 50 L / min, the cleaning agent is supplied to the second pipe 122 with the goal of the concentration of the cleaning agent contained in the cleaning water being 100 mg / L. Supplied.

  Prior to the addition of the cleaning agent, the lithium ion concentration of the city water and the concentration of the cleaning component were measured. The lithium ion concentration was 0.00 mg / L, and the concentration of the cleaning component was 0 m / L. Therefore, the addition of the cleaning agent to the second pipe 122 was started, and the lithium ion concentration of the cleaning water ejected from the felt shower 112 after 30 minutes was measured and found to be 0.65 mg / L. Based on this lithium ion concentration, the cleaning component concentration was determined using a conversion formula determined in advance by testing, and found to be 65 mg / L. For this reason, when the rotation speed of the pump for chemical injection provided in the pipe 162 of the second chemical injection device 132 was increased 1.55 times and the lithium ion concentration of the washing water was measured again 30 minutes later, 1.05 mg / L. Based on the measured value of the lithium ion concentration, the concentration of the cleaning agent was determined to be 105 mg / L, which was confirmed to be within the target range. Therefore, the city water and the cleaning agent were continuously supplied.

  In this way, the operation of adjusting the addition amount of the cleaning agent was performed based on the measured value of the lithium ion concentration of the cleaning water, and the felt part 20 was cleaned at a frequency of once / day for 60 days. Concentration adjustment was performed by decreasing the supply amount of the cleaning agent when it was determined that the concentration of the cleaning component was high, and by decreasing the supply amount of fresh water when it was determined that the concentration of the cleaning component was low. The lithium ion concentration was measured by atomic absorption. The time required for the measurement of the lithium ion concentration was 20 minutes, and the time from the measurement of the lithium ion concentration of the cleaning water to the completion of the concentration adjustment by controlling the rotation speed of the pump was 40 minutes.

[Example 2]
As Example 2, phosphoric acid was used in place of lithium ions as a tracer substance, and the same operation as in Example 1 was performed except that a detergent containing 2% by weight of phosphoric acid was used instead of lithium chloride in Example 1. . The phosphate ion concentration of city water ejected from the fer nozzle 112 before the addition of the cleaning agent was 0.30 mg / L. The phosphate ion concentration of cleaning water 30 minutes after the start of the supply of the cleaning agent was 1.40 mg / L, and the cleaning agent concentration calculated from the conversion formula obtained by the preliminary test was calculated to be 55 mg / L. Then, when the rotation speed of the pump for chemical injection provided in the pipe 162 of the second chemical injection device 132 was increased and the phosphate ion concentration was measured again after 30 minutes, the phosphate ion concentration was converted to 2.36 mg / L. From the equation, the concentration of the cleaning component was calculated to be 103 mg / L.

  In addition, for the measurement of phosphate ion concentration, a phosphonic acid measurement kit (manufactured by HACH) is used, the measurement time of phosphate ion is 15 minutes, and it is necessary from measurement of phosphate ion concentration of washing water to preparation of cleaning component concentration The time was 30 minutes.

[Comparative example]
Next, as Comparative Example 1, felt cleaning was performed using the same cleaning agent as in Example 1 except that the tracer substance was removed. It was difficult to measure the cleaning component in the cleaning water containing no tracer substance, and the cleaning agent concentration was not measured for the comparative example.

About Example 1, Example 2, and the comparative example, the paper machine was stopped and a part of felt was cut off and the stain | pollution | contamination was implemented. The degree of soiling was measured by extracting the soiling components in the felt with a solvent (chloroform: benzene = 1: 1) and determining the extraction amount. The measurement results are shown in the table.

  As shown in Table 1, in Example 1 and Example 2 in which the tracer substance concentration was measured and concentration control was performed, the felt cleaning effect was high. On the other hand, in the comparative example, the felt cleaning effect was low. Furthermore, for Example 1 and Example 2, the time required for measuring the concentration of the tracer substance and adjusting the concentration of the cleaning agent was about 30 minutes, and the concentration could be adjusted in a short time, whereas for the comparative example, Concentration management at the location where the paper machine 1 was installed was practically impossible.

  The present invention can be used to clean equipment used in the papermaking process.

It is a schematic diagram which shows a paper manufacturing process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Paper machine 10 Wire part 20 Press part 11 Wire 12 1st roll 15 Tank 21 Felt 22 2nd roll 111 Wire nozzle 112 Felt nozzle 121 1st piping 122 2nd piping 131 1st chemical injection device 132 2nd chemical injection device 141 First pump 142 Second pump 151 Tracer measuring instrument

Claims (4)

A cleaning agent contained in cleaning water for cleaning a paper machine,
A cleaning component that removes papermaking dirt attached to the papermaking machine, and a tracer substance that traces the concentration of the cleaning component contained in the cleaning water ,
The tracer substance is an ion tracer and is a cleaning agent for a papermaking process. The ion tracer, lithium salts, potassium salts and magnesium salts, phosphates, and cleaning agents for papermaking process of claim 1 wherein at least one selected from the nitrates. A method for managing the concentration of cleaning water for cleaning a paper machine,
The cleaning water includes a cleaning component that removes papermaking stains attached to the paper machine, and a tracer substance that traces the concentration of the cleaning component contained in the cleaning water, and measures the concentration of the tracer substance. The concentration control method of the water for washing | cleaning which adjusts the density | concentration of the said washing | cleaning component by. The concentration control method for cleaning water according to claim 3 , wherein the tracer substance is at least one selected from a lithium salt, a potassium salt, a magnesium salt, a phosphate, and a nitrate.

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