Method for treating water containing asphalt in papermaking process

Abstract

The present invention provides a technology capable of efficiently discharging asphalt contained in treated water in a papermaking process to the outside of the system. The present invention can provide a method for treating treated water containing asphalt, characterized in that it is a method for treating treated water containing asphalt in a papermaking process, the treated water containing asphalt in the aforementioned papermaking process is one or more types of treated water containing asphalt selected from a modulation process, a papermaking process, and a water recovery process, the concentration of suspended matter in the aforementioned treated water is 0.3% or more, and the asphalt is removed by aerating the aforementioned treated water to generate bubbles.

Description

Technical Field

[0001] The present invention relates to a method for treating asphalt-containing water to be treated in a papermaking process, a method for removing asphalt in a papermaking process, and an apparatus for treating asphalt-containing water to be treated. Background Art

[0002] Papermaking is carried out through a papermaking process in which paper is made from a raw material slurry obtained by dispersing a pulp raw material in water. In the papermaking process, a large amount of water containing fine fibers such as pulp and fillers is discharged from a papermaking machine or the like. From the viewpoint of effective use and reuse of water resources, the water containing pulp discharged in the papermaking process is recycled through a water recovery process or the like.

[0003] At this time, the discharged water containing pulp is repeatedly recycled, so that the used water gradually contains a large amount of asphalt generated in the papermaking process. In addition, since the old paper contains a large amount of asphalt-causing components, the water containing pulp is likely to contain a large amount of asphalt in the preparation process using the old paper as a raw material and the subsequent papermaking process.

[0004] Generally speaking, pitch refers to a resin component derived from pulp, a synthetic adhesive in recycled paper, or a hydrophobic adhesive mainly composed of an organic substance derived from an additive used in a papermaking process.

[0005] Asphalt is dispersed in the water in the form of a colloid, but when the colloidal state is destroyed due to a large change in shear force, pH change, water temperature change, addition of chemicals, etc., it will precipitate in the water, and the fine asphalt will form aggregates with each other or with fillers such as calcium carbonate, fine fibers, etc. In addition, due to the high hydrophobicity of asphalt, it is easy to adhere to papermaking tools such as metal wires and felt. As a result, sometimes aggregates derived from asphalt are mixed into the product, water extraction is poor, and paper breaks are caused. Therefore, there will be problems such as reduced product quality and yield due to asphalt, and reduced productivity due to stopping equipment and cleaning papermaking tools. This kind of failure caused by asphalt that reduces product quality and production efficiency is called asphalt failure.

[0006] Therefore, agents that can inhibit asphalt in the papermaking process, for example, have been studied. For example, synthetic polymers, inorganic agglomerating agents, etc. are used as asphalt inhibitors. Asphalt inhibitors are expected to have the effect of reducing the adhesion of asphalt or dispersing asphalts so as not to form aggregates, thereby making asphalt failure less likely to occur.

[0007] In addition, for example, Patent Document 1 proposes a method for controlling the accumulation of organic pollutants in a papermaking system starting from fibers, which includes: treating an aqueous suspension containing fibers using at least one lipase and at least one oxidant that does not contain a peroxide source, wherein the aforementioned organic pollutants include one or more asphalt components.

[0008] Prior art literature

[0009] Patent Literature

[0010] Patent Document 1: Japanese Patent Application No. 2015-527497

[0011] Non-patent literature

[0012] Non-patent document 1: Kanazawa Takeshi, Optimization of screen device related to removal of adhered foreign matter (Japanese: Optimization of screen device related to removal of adhered foreign matter), Paper Technology Association Journal, Vol. 51, No. 1, 1997, p. 40-47 Summary of the invention

[0013] Problem that the invention aims to solve

[0014] The technology such as the above-mentioned Patent Document 1 is a technology that suppresses the generation of asphalt in water containing pulp or disperses asphalt by chemical treatment, and the asphalt is not discharged outside the system. Furthermore, for example, Non-Patent Document 1 records that asphalt of a size of 400 μm or 500 μm can pass through the wire mesh device.

[0015] Therefore, the present inventors have studied a technique capable of efficiently discharging the pitch contained in the water containing pulp to the outside of the system.

[0016] That is, the main object of the present invention is to provide a technology capable of efficiently discharging asphalt from water containing asphalt in a papermaking process to the outside of the system.

[0017] Solutions for solving problems

[0018] In order to solve the above-mentioned problems, the inventors paid attention to the properties of the water containing asphalt in the preparation process, papermaking process and water recovery process, and conducted in-depth research on the technology of efficiently discharging asphalt from the water containing asphalt to the outside of the system in consideration of the properties. As a result, the inventors found the following technology: by using aeration to generate bubbles in the water containing asphalt, the asphalt can be efficiently discharged from the water containing asphalt to the outside of the system, thereby completing the present invention. That is, the present invention is as follows.

[0019] The present invention can provide a method for treating asphalt-containing water to be treated, characterized in that it is a method for treating asphalt-containing water to be treated in a papermaking process,

[0020] The asphalt-containing water to be treated in the papermaking process is one or more asphalt-containing water to be treated selected from the group consisting of a preparation process, a papermaking process, and a water recovery process.

[0021] The concentration of suspended matter in the treated water is above 0.3%.

[0022] The asphalt is removed by aerating the treated water to generate bubbles.

[0023] The present invention provides a method for removing asphalt, characterized in that it is the method for removing asphalt from asphalt-containing water to be treated in a papermaking process.

[0024] The asphalt-containing water to be treated in the papermaking process is one or more asphalt-containing water to be treated selected from the group consisting of a preparation process, a papermaking process, and a water recovery process.

[0025] The concentration of suspended matter in the treated water is above 0.3%.

[0026] Asphalt is removed by supplying air bubbles to the water to be treated.

[0027] The present invention can provide a treatment device for water to be treated containing asphalt, which comprises:

[0028] A tank for treating treated water containing bitumen;

[0029] An aeration device configured to generate bubbles in the water to be treated by aeration;

[0030] A stirring device configured to generate convection in the water to be treated by stirring; and

[0031] A foam removal device is configured to remove foam formed by asphalt adhering to air bubbles by performing the aeration and the stirring in the same tank.

[0032] The particle size of the asphalt may be greater than 20 μm.

[0033] The aforementioned treated water may be treated water after screen treatment.

[0034] The foam formed by the asphalt adhering to the air bubbles can be removed.

[0035] The selective concentration ratio of the bitumen in the foam can be set to 3 or more.

[0036] A nonionic surfactant having an HLB value of 12 or less may be further added to the water to be treated.

[0037] The apparatus for treating the asphalt-containing water to be treated may implement the method for treating the asphalt-containing water to be treated in the papermaking process or the method for removing asphalt in the papermaking process.

[0038] Effects of the Invention

[0039] According to the present invention, it is possible to provide a technique capable of efficiently discharging pitch from water containing pitch in a papermaking process to the outside of the system.

[0040] It should be noted that the effects of the present invention are not necessarily limited to the effects described here, and may be any effects described in this specification. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is a schematic diagram showing an example of the papermaking process (preparation process, papermaking process, water recovery process) according to the present embodiment, and the process of the present embodiment is not limited to this.

[0042] FIG2 is a schematic diagram showing an example of a location where the device according to the present embodiment is installed. Figure 2A This is an example of a modulation process. Figure 2B and Figure 2C These are examples of the papermaking process, and the installation location of the apparatus of this embodiment is not limited to these. DETAILED DESCRIPTION

[0043] Hereinafter, the mode for implementing the invention will be described. It should be noted that the following embodiment shows an example of a representative embodiment of the present invention, but the scope of the present invention is not limited thereto. It should be noted that the upper limit and lower limit of the numerical value can be arbitrarily combined as desired.

[0044] 1. Method for treating asphalt-containing water in a papermaking process according to the present invention

[0045] The present invention can provide a method for treating asphalt-containing treated water, characterized in that it is a method for treating asphalt-containing treated water in a papermaking process, wherein the asphalt is removed by aerating the treated water to generate bubbles. More preferably, the asphalt removed is foam formed by adhering to the bubbles.

[0046] The asphalt-containing treated water in the papermaking process is preferably one or more asphalt-containing treated water selected from the preparation process, the papermaking process and the water recovery process. Furthermore, the asphalt-containing treated water in the preparation process using waste paper other than newspaper waste paper as raw material is preferably used.

[0047] The concentration of suspended matter in the water to be treated is preferably 0.3% or more and / or the particle size of asphalt is preferably 20 μm or more.

[0048] The aforementioned treated water is suitably treated water after screen treatment, and is more suitably treated water after screen treatment and before a subsequent process.

[0049] As a more preferred embodiment, a nonionic surfactant is suitably added to the water to be treated, a nonionic surfactant having an HLB value of 12 or less is more suitably added, and a polyalkylene glycol having an HLB value of 12 or less is further suitably added.

[0050] The present inventors have conceived the following hypothesis regarding the mechanism of action of removing asphalt by the method of this embodiment, but there are still many unknown points, and the present inventors have further conducted in-depth studies on the mechanism of action of the present invention.

[0051] In the tank for treating the treated water containing asphalt, the bubbles generated by aeration are hydrophobic compared to water. On the other hand, asphalt is also a hydrophobic foreign matter. And, by blowing bubbles into the papermaking slurry with specific properties by aeration, the asphalt contained in the water is transferred from the water to the bubble surface by the hydrophobic interaction. Furthermore, the asphalt attached to the bubble surface moves to the water surface of the slurry due to the floating of the bubbles, and exists near the water surface in the form of scum with concentrated asphalt.

[0052] Near the water surface, fine foam scum formed by asphalt adhering to bubbles is concentrated and presents a highly dense state. Therefore, this highly dense foam scum can be discarded outside the system with the flow of the water surface, or recovered and discharged outside the system using a foam removal device such as a scraper.

[0053] By combining papermaking slurry having specific properties with aeration in this manner, the pitch contained in the papermaking slurry can be selectively discharged to the outside of the system.

[0054] Furthermore, since the asphalt content in the treated water obtained by efficiently removing asphalt from the water to be treated containing asphalt is well reduced, the treated water can be transferred to the preparation step and / or the papermaking step and reused.

[0055] This reduces the asphalt content in the system, and makes it possible to suppress asphalt-derived troubles in the system (particularly in the papermaking process).

[0056] As a result, asphalt can be efficiently discharged to the outside of the system from one or more asphalt-containing water to be treated selected from the preparation step, papermaking step, and water recovery step in the papermaking process.

[0057] It should be noted that the process of the embodiment described in the present invention can be applied to manufacturing, devices or systems. For example, in the case of a papermaking process, the papermaking process can be set as papermaking (papermaking), a papermaking device or a papermaking system.

[0058] 1-1. Overview of the papermaking process

[0059] The papermaking process to which the method of the present embodiment is applied is not particularly limited, and the method of the present embodiment can be applied to a known papermaking process or a papermaking process that may appear in the future.

[0060] The papermaking process in this embodiment preferably includes a preparation process, a papermaking process, and a water recovery process. Figure 1 , but the process of this embodiment is not limited to this.

[0061] The preparation step may be a general preparation step, and may be constituted by, for example, adjusting and mixing raw materials (pulp, etc.) used in papermaking to produce papermaking raw materials. The papermaking step may be a general papermaking step, and may be constituted by papermaking raw materials using a papermaking machine. The water recovery step may be a general water recovery step, and may be constituted by, for example, recovering, circulating or discharging water generated in the preparation step and / or the papermaking step, and is preferably a step for recovering water generated in the papermaking step.

[0062] The method of the present embodiment is suitable for treating water to be treated containing asphalt in one or more of the preparation step, papermaking step, and water recovery step in the papermaking process.

[0063] The preparation step, papermaking step, and water recovery step in this embodiment are described in detail below (for example, see Figure 1 ), but the various steps of this embodiment are not limited thereto.

[0064] 1-1-1. Preparation process

[0065] The preparation step is not particularly limited and may be a common preparation step, and examples thereof include a step of preparing chemical pulp, mechanical pulp, or waste paper pulp.

[0066] The preparation step in the method of this embodiment is preferably a preparation step using waste paper as a raw material. Waste paper contains a component that is a source of asphalt, but the method of this embodiment can efficiently discharge asphalt from water containing asphalt in the preparation step using waste paper as a raw material to the outside of the system.

[0067] In the preparation process, the used paper used as the raw material is not particularly limited, and examples thereof include newspaper used paper, corrugated paper (cardboard box used paper and liner used paper, etc.), white used paper and high-quality used paper (white paper with 100% virgin pulp, white paper using used paper as the raw material, ordinary paper, high-quality paper, etc.), defective used paper (impurity used paper, miscellaneous used paper, title deed used paper, recycled paper, etc.), etc., and one or more selected from them can be used.

[0068] Examples of the waste paper pulp obtained in the waste paper preparation step include newspaper waste paper pulp, corrugated paper waste paper pulp, white waste paper pulp, high-quality waste paper pulp, and defective waste paper pulp. One or more of these waste paper pulps may be used as a pulp raw material for papermaking, and the waste paper pulp may be included and further chemical pulp and / or mechanical pulp may be included.

[0069] The used paper used in the used paper preparation step is preferably used paper other than newspaper used paper. In the method of this embodiment, preferably, newspaper used paper is substantially not contained relative to the total amount of used paper, and for example, newspaper used paper is 5%, 3%, 1% or less than 0.5% of the total amount of used paper. It should be noted that the asphalt-containing treated water in the papermaking step and the water recovery step may contain used paper pulp, and the used paper pulp may contain newspaper used paper pulp.

[0070] The method of this embodiment preferably uses asphalt-containing treated water in the preparation step of manufacturing papermaking raw materials using waste paper other than newspaper waste paper as raw material, and in this preparation step, the preparation step of newspaper waste paper using newspaper waste paper as raw material is preferably excluded.

[0071] Examples of the preparation process include a dissolution process using a pulper device, a dissociation process using a kneader device, a dust removal process using a cleaner device and / or a screen device, a cleaning and / or concentration process using a concentrator device, a beating process using a homogenizer device, and combinations thereof.

[0072] The cleaner step in the dust removal step is a step configured to separate large foreign matter such as sand and stapler needles mixed in the raw material using a separation device such as a cleaner device.

[0073] The screen process in the dust removal process is a process that is constituted by removing foreign matter that cannot pass through the slit width set by the screen device. As screen methods, slit screen methods and hole screen methods can be listed, but are not limited to them. As an example, in the case of a slit screen with a specified slit width (for example, 400 μm or 500 μm), for example, when the treated water containing asphalt is passed through the slit screen with a specified slit width, foreign matter larger than the specified size (for example, 400 μm or 500 μm) contained in the treated water containing asphalt cannot pass through the slit width and is removed.

[0074] In the method of the present embodiment, it is preferable that the following order is used: in the dust removal step, a cleaner step for removing large foreign matter is performed, and then a screen step for removing small foreign matter is performed.

[0075] As the modulation process, it is preferred to carry out the process in the order of a dissociation process, a dust removal process, a concentration process and a beating process. Prior to these processes, the process may be carried out in the order of a dissolution process and a dust removal process for dissolving the raw materials, and then in the order of a dissolution process and a dust removal process, and a dissociation process, a dust removal process, a concentration process and a beating process.

[0076] In the method of the present embodiment, it is preferred to treat the water containing asphalt in the screen process and the subsequent process in the dust removal process in the modulation process. It should be noted that "and thereafter" refers to the modulation process, papermaking process and water recovery process after the screen process. In the present embodiment, as a more suitable method, one or more types of water containing asphalt selected from the washing and / or concentration process, the beating process, and then the papermaking process and the water recovery process are treated.

[0077] According to the method of this embodiment, even asphalt of a size that passes through a dust removal device such as a wire mesh can be efficiently discharged outside the system. Therefore, it is more preferable to treat the treated water containing asphalt after dust removal treatment (preferably after wire mesh treatment). Therefore, it is more preferable from the viewpoint of providing treated water with reduced asphalt and suppressing subsequent processes and subsequent asphalt failure (for example, see Figure 2A ).

[0078] Generally speaking, in the case of the deinked pulp production process, there are listed a dissociation process, a first dust removal (rough selection) process, a deinking process, a second dust removal (fine selection) process, a washing process, a bleaching process using a drying tower or the like, and a storage process using a box or the like, and these processes are sometimes performed sequentially.

[0079] The main purpose of the method of this embodiment is to efficiently discharge the asphalt that could not be handled in the papermaking process in the past to the outside of the system, and further, to handle the asphalt that passes through the wire mesh as described above. Therefore, it is ideal that the method of this embodiment does not use the water containing asphalt in the deinking process, but uses the treated water containing asphalt in other processes other than the deinking process.

[0080] The method of this embodiment can handle asphalt that has passed through the wire mesh as described above, so in the case of a papermaking process including a deinking process, it is preferable to treat the asphalt-containing water to be treated in the papermaking process or the water recovery process. Asphalt that has passed through the wire mesh process can be treated more effectively, thereby providing treated water with reduced asphalt.

[0081] It should be noted that the preparation system or preparation device for performing the preparation step may be configured so as to produce a papermaking raw material, and a general preparation system or preparation device may be used.

[0082] 1-1-2. Papermaking process

[0083] The papermaking step is not particularly limited, and may be a common papermaking step.

[0084] The papermaking process includes: a paper layer forming process in which the prepared papermaking raw material (selected paper stock) is flowed onto a net by a wire member and filtered to form a paper layer; a wet paper dewatering process in which the obtained wet paper and a felt (wool felt) are passed between two rollers by a pressurizing member to perform dehydration; and a primary water circulation process in which the water generated by these processes is recovered by a storage part and a flow path (silo, pit, pipe, etc.) and the like (especially water containing pulp) and circulated in a seed box, a box, etc., and the water in this papermaking process contains asphalt in addition to pulp. It should be noted that in the papermaking process, after the wet paper dewatering process, a wet paper drying process in which the wet paper is dried by a drying mechanism component may be included.

[0085] In the method of this embodiment, it is preferred to treat one or more asphalt-containing water to be treated selected from the paper layer forming step, wet paper dehydrating step, and primary circulating water step in the papermaking step.

[0086] In the method of the present embodiment, the water generated and / or the recovered water in the papermaking process contains asphalt, and therefore, the water containing asphalt can be treated as the treated water containing asphalt. As a more suitable method, for example, spray water in the wire member, washing water of the wire and felt, etc., water or filtrate recovered from the sealing pit, white water silo and recovery water tank, etc., can be listed, and one or more of the treated water containing asphalt selected from them can be treated.

[0087] The papermaking system or papermaking apparatus for performing the papermaking step may be configured to be capable of making paper, and a general papermaking system or papermaking apparatus may be used.

[0088] As a papermaking system or papermaking device, for example, it has a wire component, a pressure component and a dryer component, but is not limited to them. Furthermore, it can further have one or more selected from a dust removal device such as a wire mesh, a box (such as a mixing box, a machine box, etc.), a homogenizer, a seed box and an inlet, a white water silo, a sealed pit, a recovery water tank, a white water recovery water flow path, etc.

[0089] 1-1-3. Water recovery process

[0090] The water recovery process is not particularly limited, but is generally configured to recover and circulate water (e.g., spray water, washing water, excess water, white water, filtrate, etc.) generated in each process of the papermaking process (more preferably, the preparation process and / or the papermaking process) in order to reuse it in the preparation process and / or the papermaking process. The water recovery process includes, for example, one or more selected from a dust removal device such as a wire mesh, a pressurized floating device, a plastic disk filter, a water storage part, a box, a pipe, a flow path, a pump, etc., which are preferably connected to form a network in a manner suitable for the purpose so that water can be recovered, circulated, or treated.

[0091] In the method of the present embodiment, the water recovered, circulated, and reused in the water recovery step contains asphalt, and therefore, it is preferred that the water containing asphalt in the water recovery step be treated as water to be treated containing asphalt.

[0092] The water recovery process in this embodiment preferably includes a primary water circulation process and a secondary water circulation process. Generally, the water circulation in the papermaking process is called the primary circulation, and the water circulation generated in the papermaking process and transferred to the outside of the process for circulation is called the secondary circulation.

[0093] As an example, in the primary water circulation step, it is preferred that water generated in the papermaking step be recovered, and the recovered water be circulated and reused in the papermaking step.

[0094] As an example, the secondary circulation water step is preferably configured so that water generated in the papermaking step is recovered and the recovered water is transferred to the preparation step for reuse or discharged to the outside of the system.

[0095] The water recovery system or water recovery device for performing the water recovery process is constructed in a manner that recovers water generated by each process or transfers water to a target device or allows water to circulate. It can be constructed in a manner that includes, for example, a water storage portion, a box, piping, a flow path, a pump, a dust removal device such as a wire mesh, etc. and is connected into a network according to the purpose.

[0096] 1-2. Treated water containing asphalt

[0097] The asphalt-containing treated water used in this embodiment is suitable for asphalt-containing water in the papermaking process as described in the above "1-1.", and the asphalt-containing water may contain pulp, and the pulp may be any of virgin pulp, waste paper pulp or a mixture thereof.

[0098] In a preferred embodiment, the asphalt-containing water to be treated in the papermaking process is one or more asphalt-containing water to be treated selected from the group consisting of a preparation process, a papermaking process, and a water recovery process.

[0099] In addition, the method for measuring the properties of the asphalt-containing water to be treated in the present embodiment is described in <Measuring method used in the present embodiment> in [Examples] described later.

[0100] The properties of the treated water containing asphalt used in this embodiment are described below. It can be diluted (e.g., water dilution) and / or concentrated (e.g., heat, membrane, reduced pressure) in a manner that is within a suitable numerical range. The dilution or concentration can be performed by a device configured to dilute and / or concentrate the treated water containing asphalt. The pH of the treated water is not particularly limited, but is preferably pH 5 to 13, and more preferably pH 5 to 10.

[0101] 1-2-1. Pulp concentration of treated water containing asphalt

[0102] The pulp concentration contained in the treated water containing asphalt is not particularly limited, and as a more suitable lower limit, it is preferably 1000 mg / L or more, more preferably 2000 mg / L or more, and further preferably 3000 mg / L or more, and as a more suitable upper limit, it is preferably 35000 mg / L or less, more preferably 30000 mg / L or less, and further preferably 25000 mg / L or less, and as a suitable numerical range, it is more preferably 1000 to 35000 mg / L, and further preferably 3000 to 30000 mg / L. As a result, asphalt can be more efficiently discharged from the asphalt-containing water in the preparation process, papermaking process, and water recovery process to the outside of the system, so the amount of asphalt in the system can be reduced, and asphalt failure can be suppressed.

[0103] It should be noted that the pulp concentration (mg / L) can be calculated based on the weight of suspended matter (mg / L) - the weight of ash (mg / L) - the weight of asphalt (mg / L).

[0104] 1-2-2. Suspended matter concentration (SS concentration) of treated water containing asphalt

[0105] The concentration of suspended matter contained in the treated water containing asphalt is not particularly limited. As a more suitable lower limit, it is preferably 0.3% or more, more preferably 0.4% or more. In addition, as a more suitable upper limit, it is preferably 10% or less, more preferably 5% or less, further preferably 4% or less, and further preferably 3% or less. As a suitable numerical range, it is more preferably 0.3-10%, and further preferably 0.4-5%. It should be noted that the suspended matter concentration can be obtained according to the "(1) Suspended matter concentration" in the <Measurement method used in this embodiment> described later.

[0106] As a result, asphalt can be more efficiently discharged from asphalt-containing water in at least any one of the preparation step, papermaking step, or water recovery step to the outside of the system, thereby reducing the amount of asphalt in the system and suppressing asphalt failure in the system.

[0107] The inventors of the present invention have discovered that, in the method of the present embodiment, as shown in the examples described below, if the concentration of suspended matter in the treated water containing asphalt is between 0.1% and 0.2%, the selective concentration ratio of the asphalt in the foam decreases slightly, but if it exceeds 0.2%, it rises sharply to 0.5%, showing a high concentration ratio.

[0108] Furthermore, when the suspended matter in the treated water containing asphalt becomes a high concentration rather than a low concentration, it is usually assumed that the amount of agents such as asphalt inhibitors should be increased. However, in the method of the present embodiment, in the papermaking process, even if the treated water containing asphalt has a high concentration of suspended matter, the asphalt can be discharged more efficiently outside the system. Moreover, mechanical aeration is used in the method of the present embodiment, so asphalt can be discharged more easily from the treated water containing asphalt to the outside of the system compared to using agents that require concentration adjustment. Furthermore, in the method of the present embodiment, even if the asphalt is of such a size that passes through the wire mesh, even if the concentration of suspended matter in the treated water containing asphalt is a high concentration above the prescribed level, the asphalt can be discharged more efficiently outside the system. As such, in the method of the present embodiment, even in the case where it is difficult to remove the asphalt, the asphalt can be efficiently discharged from the treated water containing asphalt to the outside of the system. As a result, the asphalt content in the system can be reduced, and asphalt failures in the system (especially in the papermaking process) can be suppressed.

[0109] 1-2-3. Size of asphalt in the treated water containing asphalt (particle size)

[0110] The size (particle size) of the asphalt contained in the asphalt-containing treated water is not particularly limited. As a suitable lower limit, it is preferably 10 μm or more, more preferably 15 μm or more, and further preferably 20 μm or more. As a suitable upper limit, it is preferably 1000 μm or less, more preferably 800 μm or less, further preferably 600 μm or less, further preferably 500 μm or less, and further preferably 425 μm or less. As a more suitable numerical range, it is more preferably 20 μm or more and 500 μm or less, and further preferably 20 μm or more and 425 μm or less. It should be noted that the size of the asphalt can be obtained by sieving as described in "(2) Asphalt particle size" in the <Measurement method used in the present embodiment> described later.

[0111] General asphalt inhibitors and other agents can effectively treat asphalt with a size of less than several tens of μm, but are not suitable for treating asphalt with a size of more than several tens of μm, especially more than 100 μm. Furthermore, asphalt is usually removed using a wire mesh, but asphalt is highly flexible, so it can be confirmed that asphalt with a changed shape and a size larger than the slit width, such as asphalt with a size of 400 μm or 500 μm, will pass through the wire mesh (Non-Patent Document 1). In the case where such a large asphalt is contained in the treated water, even if the conventional agent treatment or mechanical treatment is used, there is a technical difficulty that it is difficult to fully discharge it out of the system.

[0112] However, by using the method of this embodiment, even the treated water containing large asphalt with a pitch size of 10 μm or more can be well treated, and the asphalt can be well removed from the treated water. As such, according to this embodiment, even large asphalt can be efficiently discharged outside the system, so the amount of asphalt in the system can be reduced, and asphalt failure can be suppressed. In addition, the treated water with reduced large asphalt can be reused in the modulation process and / or papermaking process.

[0113] 1-2-4. Ash content of treated water containing asphalt

[0114] The amount of ash contained in the treated water containing asphalt is not particularly limited. As its suitable lower limit, it is preferably 100 mg / L or more, more preferably 300 mg / L or more, and further preferably 400 mg / L or more. In addition, as its suitable upper limit, it is preferably 10000 mg / L or less, more preferably 7000 mg / L or less, and further preferably 5000 mg / L or less. As its suitable numerical range, it is more preferably 300 to 7000 mg / L, and further preferably 400 to 5000 mg / L. As a result, asphalt can be more efficiently discharged from the water containing asphalt in the preparation process, papermaking process, and water recovery process to the outside of the papermaking system.

[0115] 1-3. Asphalt removal process

[0116] The method of this embodiment can remove asphalt by aeration to generate bubbles in the above-mentioned treated water containing asphalt. By using aeration, asphalt can be selectively attached to bubbles to form foam and float to the vicinity of the water surface. In this way, asphalt can be floated and separated and discharged outside the system.

[0117] As a more specific description, bubbles are generated by aeration, and the asphalt present in the water is brought into contact with the bubbles, so that the asphalt is attached to the bubbles and floats to the vicinity of the water surface, and is concentrated near the water surface, thereby forming foam. Since the asphalt concentration in the foam becomes highly dense, the asphalt contained in the foam in a highly dense manner can be efficiently and easily recovered by treating the vicinity of the water surface. The recovered foam can be easily discharged to the outside of the system. In this way, the asphalt can be efficiently discharged from the asphalt-containing treated water in the papermaking process to the outside of the system and the asphalt content in the system can be reduced. As a result, asphalt failures in the system can also be suppressed. In addition, the asphalt content in the resulting treated water is reduced, and failures caused by asphalt are also reduced, so it can be better reused in the modulation process and / or papermaking process.

[0118] In the asphalt removal process of the present embodiment, it is preferred to include a bubble generation process for generating bubbles by aeration and / or stirring, and it is preferred to include a foam removal process for discharging the foam containing asphalt formed by the bubbles to the outside of the system after the bubble generation process. In the asphalt removal process of the present embodiment, it is more preferred to include a bubble generation process and a foam removal process.

[0119] 1-3-1. Aeration method for water containing asphalt

[0120] The aeration method is not particularly limited, and a known aeration method can be used. In the aeration method, air bubbles may be supplied to the water to be treated containing asphalt.

[0121] As the aeration method, for example, a method using a diffuser or a stirring device can be adopted. Aeration can also be achieved by vigorously stirring the mixture by entrapping air using a stirring device configured to enable aeration, but aeration is preferred because it is easy to adjust the size, direction, amount, etc. of the bubbles.

[0122] Furthermore, from the viewpoint of being able to perform aeration stably and continuously, it is preferred to adopt a method using a diffuser (e.g., flotation, etc.) having a bubble generator capable of generating bubbles using diffuser members such as a diffuser pipe and a diffuser plate. As a method using a diffuser, as a more suitable mode, by providing a bubble generator (or a device) at the bottom of the tank, fine bubbles are blown upward from the bottom to the bottom and / or the top, thereby improving the contact efficiency between the asphalt-containing water to be treated and the bubbles, so that aeration can be performed efficiently.

[0123] The bubble generating unit is not particularly limited, but preferably uses a method in which a bubble generating unit is configured to generate fine bubbles. The bubble generating unit may transport bubbles in any direction of the bottom surface, side direction, or top of the groove, thereby spraying bubbles downward, side direction, or top direction to generate convection.

[0124] The particle size of the bubbles produced in the method of this embodiment is not particularly limited, but is preferably fine bubbles. Its suitable lower limit is preferably 0.5 mm or more, more preferably 1 mm or more, and its suitable upper limit is preferably 10 mm or less, more preferably 5 mm or less, and further preferably 3 mm or less. Its suitable numerical range is more preferably 1 to 3 mm.

[0125] The amount of gas aerated in the method of this embodiment is not particularly limited. The lower limit is preferably 0.5 L / min or more, more preferably 0.7 L / min or more, further preferably 1 L / min or more, and further preferably 1.2 L / min or more per 1 L of sample water. The upper limit is not particularly limited and can be appropriately set according to the performance of the aeration device used. The gas is preferably air. In addition, in the method of this embodiment, the aeration time is not particularly limited and can be appropriately set according to the performance of the aeration device used or the size of the tank used.

[0126] The water temperature of the asphalt-containing treated water during aeration in the method of the present embodiment is not particularly limited, and its suitable lower limit is preferably 20° C. or higher, more preferably 30° C. or higher, and more preferably 35° C. or higher, and its suitable upper limit is preferably 50° C. or lower, and more preferably 45° C. or lower. Its suitable numerical range is more preferably 20 to 50° C. As a result, foam is easily formed when the asphalt contacts the bubbles, and thus the asphalt can be efficiently discharged from the asphalt-containing treated water to the outside of the system.

[0127] It should be noted that the water temperature of the asphalt-containing water to be treated in the "1-3-2. Method for removing foam containing asphalt" described later can adopt the temperature conditions of the above-mentioned "water temperature of the asphalt-containing water to be treated during aeration", and is more preferably 20 to 50°C.

[0128] In the method of this embodiment, it is preferred that the asphalt-containing treated water is stirred in a manner that generates convection on the basis of aeration. The convection is more preferably vertical convection or horizontal convection. Thus, the bubbles can be made to contact the asphalt-containing treated water in the tank evenly, and foam is easily formed when the asphalt contacts the bubbles, so that the asphalt can be efficiently discharged from the asphalt-containing treated water to the outside of the system.

[0129] The stirring method is not particularly limited, and preferably a method using a stirring device configured to generate convection in the treated water containing asphalt is adopted. As the stirring device, for example, a single or multiple stirring blade type, a jet type, etc. underwater stirring device can be listed, but it is not limited to this.

[0130] 1-3-2. Method for removing foam containing asphalt

[0131] There are no particular limitations on the foam removal method, and a common method using a foam removal device can be used. As the foam removal method, a method using the following mechanisms or devices can be used: a mechanism or device configured so that the foam near the water surface is discharged along with the water flow near the water surface; a mechanism or device configured so as to scrape the foam near the water surface. Due to the aforementioned aeration method, highly densely concentrated foam exists near the water surface in the tank. Therefore, even if a simple device or mechanism is used, asphalt can be more efficiently and easily discharged from the treated water containing asphalt to the outside of the system. It should be noted that the conditions for removing foam can appropriately adopt the above-mentioned "1-3-1." conditions (such as water temperature).

[0132] As a method of discharging foam using a water flow near the water surface, more specifically, it is preferable to adopt a method using, for example, a mechanism or device that brings the foam near the water surface closer and causes it to fall into a drain port located slightly higher or lower than the water surface and be removed.

[0133] In addition, as a method for scraping foam near the water surface, more specifically, a method using, for example, a scraper plate moving or rotating device (KROFTA), a collecting robot (automatic floating matter recovery device), a micro skimmer (ultra-small floating matter recovery device) or other skimmers, etc., is preferably adopted. One or more selected from these can be used.

[0134] These mechanisms or devices include, for example, devices (scraping devices, recovery devices, transfer pumps, etc.), grooves, flow paths, etc., and can be configured to discharge the asphalt outside the system. For example, it can be a foam removal device configured to remove the foam formed by the asphalt adhering to the bubbles. The mechanism or device can be connected to other parts (such as devices (pumps, etc.), grooves, flow paths, etc.) to eventually discharge the asphalt outside the system.

[0135] 1-3-3. Selective concentration ratio of asphalt in foam

[0136] In the method of the present embodiment, the asphalt is removed by generating bubbles in the water to be treated containing asphalt by aeration, thereby making it possible to increase the selective concentration ratio of the asphalt in the foam.

[0137] Furthermore, in the method of the present embodiment, by treating the water to be treated containing asphalt so as to increase the selective concentration ratio of asphalt in the foam, asphalt can be efficiently discharged from the water to be treated containing asphalt to the outside of the system.

[0138] In addition, the asphalt content in the treated water after the asphalt is efficiently removed from the asphalt-containing treated water is greatly reduced, and the treated water can be transferred to the preparation process and / or papermaking process for reuse. By using this treated water, asphalt failures occurring in the papermaking process can be reduced.

[0139] The more suitable lower limit of the selective concentration ratio of asphalt in the foam in the method of the present embodiment is preferably 2 or more, more preferably 3 or more, further preferably 4 or more, further preferably 5 or more, more preferably 5.5 or more, and more preferably 6 or more. The upper limit of the selective concentration ratio of asphalt in the foam is not particularly limited because the method of the present embodiment can perform two-stage or three-stage continuous treatment, and can be, for example, 500 or less, 250 or less, or 100 or less, and can also be 10 or less, 20 or less, or 50 or less. When the concentration of suspended matter in the water to be treated containing asphalt is 0.5% or more, the selective concentration ratio of asphalt in the foam increases rapidly, and therefore, in the method of the present embodiment, it is more preferably used in a process in which the concentration of suspended matter becomes high.

[0140] 1-3-4. Use of medicine

[0141] As a suitable aspect of the method of this embodiment, when performing the aeration, it is preferred that the water to be treated containing asphalt further contains a chemical in order to increase the adsorption selectivity of asphalt to bubbles or to further increase the asphalt removal rate.

[0142] The agent can be used to improve the adsorption selectivity of asphalt to bubbles or to improve the asphalt removal rate, or the composition or preparation used for the purpose can be made into a composition or preparation containing the agent for improving the adsorption selectivity of asphalt to bubbles or for improving the asphalt removal rate. The agent can be used to prepare a composition or preparation for improving the adsorption selectivity of asphalt to bubbles or for improving the asphalt removal rate. The agent can be added for the method of improving the adsorption selectivity of asphalt to bubbles or the method of improving the asphalt removal rate. It should be noted that the agent used in this embodiment can be obtained and used by a known manufacturing method, or a commercially available product can be used.

[0143] 1-3-4-1.HLB value

[0144] The HLB value of the reagent is not particularly limited, but its upper limit is preferably 14 or less, more preferably 13 or less, and further preferably 12 or less. By using a reagent with a low HLB value and high hydrophobicity in combination, the concentration effect of asphalt during recovery can be further improved. In addition, the lower limit of the HLB value of the reagent is preferably 6 or more, more preferably 8 or more, and further preferably 10 or more, so that it is easy to contact with the asphalt in the water to be treated, and when aerating it, the asphalt is easily attached to the air bubbles and separated and floated from the water to be treated.

[0145] The HLB value is a method for calculating HLB proposed by Oda et al., and is well known to those skilled in the art (Ryohei Oda et al., "Synthesis and Application of Surfactants", Maki Shoten (1964)). The HLB value is calculated using the following (Formula 1). The "inorganic value" and "organic value" in the following (Formula 1) are values ​​predetermined for each compound, and the HLB is calculated by using these values ​​and summing them for the entire compound.

[0146] HLB = (Σinorganic value / Σorganic value) × 10… (Mathematical formula 1)

[0147] 1-3-4-2. Surfactants

[0148] As a drug, a surfactant is preferred, and more specifically, a surfactant having a hydrophobic group is preferred. The hydrophobic group is preferably an alkyl group and / or an alkylene group, which may be any of a straight chain, a branched chain or a cyclic chain, and more preferably a straight chain or a branched chain. More specifically, examples include alkyl groups having 1 to 4 carbon atoms, such as methyl, propyl, and butyl; and alkylene groups having 1 to 4 carbon atoms, such as methylene, ethylene, propylene, and butylene, which may be one or more selected from them. They may be a single polymer or a copolymer with other monomers.

[0149] Furthermore, as a suitable embodiment of the drug, a nonionic surfactant is preferred, and a polyalkylene glycol is more preferred. The polyalkylene glycol can be represented by the following (Chemical Formula 1).

[0150] HO-(RO) n -H…(Chemical Formula 1)

[0151] In the above (chemical formula 1), R is preferably a linear or branched alkylene group having 1 to 4 carbon atoms, and n is an integer, preferably n≥450 (suitably n≥20).

[0152] The "alkylene group" in the aforementioned (chemical formula 1) is preferably the same as the above-mentioned "alkylene group", more preferably having 1 to 3 carbon atoms, and further preferably ethylene. The "n" is preferably about 5 to 20, and more preferably 5 to 10.

[0153] 1-3-4-3. Number average molecular weight

[0154] The number average molecular weight of the drug (polymer) used in the present embodiment is not particularly limited. Its suitable lower limit is preferably 100 or more, more preferably 200 or more, and further preferably 300 or more. In addition, its suitable upper limit is preferably 3000 or less, more preferably 2000 or less, and further preferably 1000 or less.

[0155] The number average molecular weight of the “polymer” or water-soluble high molecular weight polymer used in the present embodiment can be measured by GPC (gel permeation chromatography) analysis using standard polystyrene as a standard substance.

[0156] 1-3-4-4. Dosage of medicine

[0157] The amount of the agent used in the present embodiment is not particularly limited. With respect to the treated water containing asphalt, its suitable lower limit is preferably 0.1 mg / L or more, more preferably 0.5 mg / L or more, and further preferably 1 mg / L or more. In addition, its suitable upper limit is preferably added appropriately by observing the foaming conditions. It is not particularly limited, but is preferably 50 mg / L or less, more preferably 20 mg / L or less, further preferably 10 mg / L or less, and further preferably 5 mg / L or less.

[0158] Furthermore, the chemical is preferably added in the step of treating water to be treated containing asphalt or in the step of removing asphalt.

[0159] As the place where the reagent is used, it is more preferably a place or device for treating the treated water containing asphalt or removing the asphalt, or its upstream. As the upstream, pipes or flow paths connected to the place or device for treating or removing the asphalt can be suitably listed.

[0160] As a more suitable method, it is preferred to add the agent at the aeration site or upstream thereof. More specifically, it is preferred to add the agent to a tank configured to generate bubbles by aeration or to a process or flow path before the tank. As the process or flow path before the tank, it is preferred to be a pipe or flow path connected to the tank and immediately before the tank flows.

[0161] 1-3-5. Example of this embodiment

[0162] In the method for treating water containing asphalt according to the embodiment, as a more specific embodiment, for example, Figure 1 The papermaking process 1 includes a preparation process 2, a papermaking process 3, and a water recovery process 4 for recovering water generated in each of these processes.

[0163] The preparation process 2 includes a dissolution process 21, a dissociation process 22, a dust removal process (cleaner process, screen process) 23, a concentration process 24, and a beating process 25. In the preparation process 2, the raw material 10 such as waste paper can be made into papermaking raw material in the dissolution process 21 to the beating process 25.

[0164] The papermaking process 3 includes a dust removal process 31, a paper layer forming process 32, a wet paper dehydration process 33, and a wet paper drying process 34, and finally forms paper 5 in the outer papermaking process. The papermaking process 3 (each process 31 to 34) is connected to a water recovery process of the primary circulation water 41 and / or the secondary circulation water 42 for recovering water (e.g., water containing asphalt and pulp, etc.) generated by washing water during papermaking.

[0165] In the water recovery step 4, water generated in the papermaking step 3 is recovered. The reusable water is circulated in the preparation step 2 and / or the papermaking step 3, and unnecessary water is discharged as wastewater 6 to the outside of the system.

[0166] The method 100 for treating asphalt-containing water to be treated in the present embodiment can be used in a papermaking process, and can be suitably used in one or more processes selected from the preparation process 2, the papermaking process 3, and the water recovery process 4. Furthermore, the method 100 for treating asphalt-containing water to be treated in the present embodiment can treat one or more processes selected from the preparation process 2, the papermaking process 3, and the water recovery process 4.

[0167] For example, Figure 2A As shown, the method 100 for treating water containing asphalt in the present embodiment can be used between the dust removal (preferably a wire screen) step 23 and the concentration step 24 in the preparation step 2 .

[0168] The treatment method 100 in this embodiment can treat the water to be treated containing asphalt after the dust removal (preferably a screen) step 23 in the preparation step 2 and before the concentration step 24.

[0169] According to the treatment method 100 of the present embodiment, the treated water with a reduced asphalt content can be transferred to the concentration step 24 , and the water containing asphalt can be discharged to the outside of the system as the waste water 6 .

[0170] In addition, for example, Figure 2B and Figure 2C As shown, the method 100 for treating water containing asphalt in the present embodiment can be used between the white water 43 containing excess white water in the papermaking step 3 and the preparation step 2 and / or the papermaking step 3 .

[0171] By the treatment method 100 of this embodiment, the treated water with reduced asphalt content is transferred to the preparation step 2 and / or the papermaking step 3, and the transfer destination of the treated water can be multiple locations. In addition, the treated water containing asphalt undergoes the secondary circulation water step 42 and is discharged to the outside of the system in the form of wastewater 6.

[0172] In addition, the method 100 for treating water containing bitumen in the present embodiment may be repeatedly performed until a predetermined value (for example, a predetermined "selective concentration ratio of bitumen in foam") is reached.

[0173] It should be noted that in the method for treating asphalt-containing water to be treated described in the embodiment of the present invention, the descriptions of "2.", "3.", etc. described below are also applicable to this embodiment and can be appropriately adopted.

[0174] 2. The method for removing asphalt from asphalt-containing treated water in a papermaking process according to the present invention

[0175] In the method for removing asphalt from treated water containing asphalt in a papermaking process described in an embodiment of the present invention, the descriptions of the various components such as asphalt, treated water, aeration, etc. that are repeated in the above-mentioned "1." and the following "3." are appropriately omitted, but the descriptions of "1.", "3.", etc. are also applicable to the present embodiment and can be appropriately adopted.

[0176] This embodiment can provide a method for removing asphalt, characterized in that it is a method for removing asphalt from asphalt-containing water to be treated in a papermaking process.

[0177] The asphalt is removed by supplying air bubbles to the water to be treated. More preferably, the air bubbles are generated by aeration, thereby supplying air bubbles (for example, see Figure 1 and Figure 2).

[0178] The asphalt-containing treated water in the papermaking process is preferably one or more asphalt-containing treated water selected from the preparation process, the papermaking process and the water recovery process. Furthermore, the asphalt-containing treated water in the preparation process using waste paper other than newspaper waste paper as raw material is preferably used.

[0179] The concentration of suspended matter in the water to be treated is preferably 0.3% or more.

[0180] The particle size of the asphalt in the water to be treated is preferably 20 μm or more.

[0181] The aforementioned treated water is suitably treated water after screen treatment.

[0182] The water to be treated preferably further contains a surfactant having an HLB value of 13 or less.

[0183] The aforementioned removal is suitable for removing the foam formed by asphalt adhering to the air bubbles.

[0184] The above-mentioned removal is preferably performed so that the selective concentration ratio of the bitumen in the foam is set to 3 or more.

[0185] As a more suitable method, the asphalt removal method in this embodiment can be used between the dust removal (suitably screen) step and the concentration step in the modulation step, or can be used between the white water containing excess white water in the papermaking step and the modulation step and / or the papermaking step.

[0186] In addition, as a more suitable manner, in the asphalt removal method of the present embodiment, the treated water containing asphalt in and after the dust removal (suitably a screen) step in the modulation step and before the concentration step can be treated, or the treated water containing asphalt in the white water silo, excess white water and / or its recovered water in the papermaking step can be treated.

[0187] According to the asphalt removal method of this embodiment, asphalt can be selectively discharged from the treated water containing asphalt to the outside of the system. Furthermore, the asphalt content in the treated water after the asphalt is efficiently removed from the treated water containing asphalt is well reduced, and the asphalt can be transferred to the preparation process and / or papermaking process for reuse. As a result, the amount of asphalt in the system is reduced, and the failure caused by asphalt in the papermaking process can be suppressed.

[0188] It should be noted that the method of the present embodiment can also be implemented by a device for implementing or managing the above-mentioned method for treating the treated water containing asphalt or the asphalt removal method (for example, the method described in the above "1." and "2.") or a control unit (the control unit includes a CPU, etc.) possessed by the device, and these devices or control units can be provided. As devices for the implementation or management, for example, computers, laptops, desktop computers, tablet PCs, PLCs, servers, cloud services, etc. can be listed. Furthermore, the devices used for the aforementioned implementation or management can appropriately have input units such as touch panels and keyboards; communication units such as information transceiver units, networks, and network access units between each unit; display units such as touch panels and displays, etc. The method of the present embodiment can thus be implemented.

[0189] In addition, the method of the present embodiment can also be stored in the form of a program in a hardware resource having a storage medium (non-volatile memory (USB memory, etc.), SSD (Solid State Drive), HDD (Hard Disk Drive), CD, DVD, Blu-ray, etc.), and implemented by the aforementioned control unit. The method of the present embodiment can be provided in the form of a program. A storage medium storing the method of the present embodiment can be provided. In this way, the method of the present embodiment can be implemented.

[0190] In addition, a system such as a treatment system for asphalt-containing treated water or an asphalt removal system that includes the control unit, the storage medium, or the program and controls the treatment of asphalt-containing treated water or the removal of asphalt can be provided. This enables the method of this embodiment to be implemented.

[0191] In addition, as an example of the present embodiment, a program for causing a computer or the like to implement the treatment of asphalt-containing treated water may be provided, wherein the treatment includes: a function of generating bubbles in the asphalt-containing treated water in a predetermined process by aeration and / or stirring; and a function of discharging the foam formed by contacting the asphalt in the asphalt-containing treated water with the bubbles to the outside of the system, but the present invention is not limited thereto. The method of the present embodiment can be implemented in this way.

[0192] In addition, as an example of this embodiment, it is preferred that the device has a control unit configured to generate bubbles in the asphalt-containing treated water in a predetermined process by aeration and / or stirring, and the control unit is more preferably configured to discharge the foam formed by contacting the asphalt in the asphalt-containing treated water with the bubbles to the outside of the system. In this way, the method of this embodiment can be implemented more effectively.

[0193] 3. The apparatus for treating water containing asphalt in the papermaking process according to the present invention

[0194] In the treatment device for treated water containing asphalt in the papermaking process described in the present invention, the descriptions of the various components such as asphalt, treated water, aeration, etc. that are repeated in the above-mentioned "1.", "2.", etc. are appropriately omitted, but the descriptions of "1.", "2.", etc. are also applicable to the present embodiment and can be appropriately adopted.

[0195] The present invention can provide a treatment device for asphalt-containing water to be treated, which comprises a tank for treating asphalt-containing water to be treated, wherein the tank is configured to remove foam formed by asphalt adhering to air bubbles by aeration (for example, see Figure 1 2 ). The tank is more preferably constructed so that aeration and / or stirring are performed in the same tank.

[0196] Furthermore, it is suitable to have a device configured to add a drug.

[0197] Furthermore, it is suitable to further include a control unit configured to execute the method of this embodiment (for example, the method described in the above-mentioned "1." and "2.").

[0198] As a preferred embodiment of the present invention, there is provided an apparatus for treating water containing asphalt, the apparatus comprising:

[0199] A tank for treating treated water containing bitumen;

[0200] An aeration device for generating bubbles in the treated water by aeration; and / or

[0201] A stirring device for causing convection of the treated water by stirring; and

[0202] The foam removal device is configured to remove foam formed by asphalt adhering to air bubbles by performing the aeration and / or stirring in the same tank.

[0203] In addition, the apparatus for treating water to be treated containing asphalt in the present embodiment can be used as an apparatus for removing asphalt (see, for example, FIG. 2 ).

[0204] Furthermore, the apparatus in this embodiment (such as a treatment apparatus and a removal apparatus) may be a treatment system for water to be treated containing asphalt or an asphalt removal system (such as referring to Figure 1 and Figure 2).

[0205] In addition, various devices constituting the device configuration in the present embodiment may be formed as parts. For example, the aeration device may be formed as an aeration part.

[0206] In addition, the tank can be configured so that the treated water containing asphalt can flow in from other parts, and further, it can be configured so that the treated water can be transferred from the tank to other parts as the target, and it can also be connected to other parts (such as devices, tanks, flow paths, etc.) so that the recovered asphalt can be discharged outside the system. The shape and size of the tank are not particularly limited.

[0207] In addition, regarding the device of the present embodiment, there is no particular limitation on the location of installation or the location of use in the papermaking process, and it can be installed or used in any process. In this case, the device of the present embodiment can be installed singly or in multiples (for example, refer to FIG. 2 ). As a suitable method in the device of the present embodiment, it is more suitable to install or use singly or in multiples in one or more of the modulation process, the papermaking process, and the water recovery process. As a more suitable method of the device of the present embodiment, it is expected to be after the screen treatment. For example, as shown in FIG. 2 , the device 100 of the present embodiment can be installed or used between the dust removal (suitable for screen) process 23 and the concentration process 24 in the modulation process 2. In addition, the device 100 of the present embodiment can be installed or used between the white water 43 containing excess white water in the papermaking process 3 and the modulation process 2 and / or the papermaking process 3. At this time, the device of the present embodiment installed or used can be singly or in multiples.

[0208] According to the device of this embodiment, asphalt can be removed efficiently and selectively from the treated water containing asphalt, and the asphalt can be finally discharged out of the system. Furthermore, treated water can be produced after the asphalt is efficiently removed from the treated water containing asphalt, and the asphalt content in the treated water is well reduced, so it can be transferred to the preparation process and / or papermaking process for reuse. As a result, the amount of asphalt in the system is reduced, and the failure caused by asphalt in the papermaking process can be suppressed.

[0209] It should be noted that, as a suitable form, the apparatus of the present embodiment can implement the method for treating water containing asphalt described in the above-mentioned “1.” and the method for removing asphalt described in the above-mentioned “2.”.

[0210] In addition, as a preferred embodiment, the apparatus of the present embodiment may be an apparatus configured to be able to implement the method for treating water containing asphalt described in "1." above and the method for removing asphalt described in "2." above.

[0211] The present invention may also adopt the following configurations.

[0212] [1] A method for treating water containing asphalt, characterized in that it is a method for treating water containing asphalt in a papermaking process,

[0213] The asphalt-containing water to be treated in the papermaking process is one or more asphalt-containing water to be treated selected from the group consisting of a preparation process, a papermaking process, and a water recovery process.

[0214] The concentration of suspended matter in the treated water is above 0.3%.

[0215] The asphalt is removed by aerating the treated water to generate bubbles.

[0216] The asphalt-containing water to be treated in the aforementioned preparation step is preferably asphalt-containing water to be treated in a preparation step using waste paper other than newspaper waste paper as a raw material.

[0217] [2] A method for removing asphalt, characterized in that it is a method for removing asphalt from water to be treated containing asphalt in a papermaking process,

[0218] The asphalt-containing water to be treated in the papermaking process is one or more asphalt-containing water to be treated selected from the group consisting of a preparation process, a papermaking process, and a water recovery process.

[0219] The concentration of suspended matter in the treated water is above 0.3%.

[0220] Asphalt is removed by supplying air bubbles to the water to be treated.

[0221] The asphalt-containing water to be treated in the aforementioned preparation step is preferably asphalt-containing water to be treated in a preparation step using waste paper other than newspaper waste paper as a raw material.

[0222] [3] The method according to [1] or [2] above, wherein the particle size of the asphalt is greater than 20 μm.

[0223] [4] The method according to any one of [1] to [3] above, wherein the water to be treated is water to be treated after a wire mesh treatment.

[0224] The pH of the water to be treated is preferably pH 5-13, more preferably pH 5-10.

[0225] [5] The method according to any one of [1] to [4] above, wherein foam formed by the asphalt adhering to air bubbles is removed.

[0226] [6] The method according to any one of [1] to [5] above, wherein the selective concentration ratio of the bitumen in the foam is set to 3 or more.

[0227] [7] The method according to any one of [1] to [6] above, wherein a surfactant having an HLB value of 13 or less (preferably 12 or less) is further added to the water to be treated.

[0228] A nonionic surfactant is suitable, and a polyalkylene glycol having an HLB value of 13 or less (preferably 12 or less) is more suitable.

[0229] [8] A treatment device for water to be treated containing asphalt, comprising a tank for treating water to be treated containing asphalt, wherein the tank is configured to remove foam formed by asphalt adhering to air bubbles due to aeration.

[0230] The device for treating the water to be treated containing asphalt may be an asphalt removal device.

[0231] Preferably, the tank is a tank configured to perform aeration and / or stirring in the same tank.

[0232] Furthermore, it is suitable to include a device configured to add a drug.

[0233] [9] The apparatus for treating water containing asphalt according to [8] above, comprising:

[0234] A tank for treating treated water containing bitumen;

[0235] An aeration device for generating bubbles in the water to be treated by aeration;

[0236] A stirring device for causing convection of the treated water by stirring; and

[0237] A foam removal device is configured to remove foam formed by asphalt adhering to air bubbles by performing the aeration and the stirring in the same tank.

[0238]

[10] An apparatus for implementing or managing the following method or the apparatus described in [8] or [9] above, further comprising a control unit configured to implement any one of the methods described in [1] to [7] above.

[0239]

[11] The apparatus according to any one of [8] to

[10] above, wherein the treatment device is provided in one or more selected from the group consisting of a preparation step, a papermaking step, and a water recovery step.

[0240] The aforementioned device may be single or multiple.

[0241]

[12] An apparatus for implementing or managing the following method or an apparatus described in any one of [8] to

[11] above, which implements the method described in any one of [1] to [7] above.

[0242]

[13] The method according to any one of [1] to [7] above, using the device according to any one of [8] to

[11] above.

[0243] Example

[0244] The following examples and comparative examples are given to explain the embodiments of the present invention. However, the scope of the present invention is not limited to the examples and the like.

[0245] [Test Example 1: Flotation Test]

[0246] As follows, samples (treated water containing asphalt and corrugated paper pulp) of Examples 1 to 5 and Comparative Examples 1 to 2 were prepared. Each sample was subjected to flotation, and fine foam scum (foam) formed by asphalt adhering to the water surface was scraped off with a scraper (scraper plate).

[0247] <Measurement Method Used in This Embodiment>

[0248] The measurement method used in this embodiment is as follows.

[0249] (1) Suspended matter concentration

[0250] The suspended solids (SS) concentrations of the treated water and the treated water were measured on the samples in accordance with JIS K0102.

[0251] (2) Asphalt particle size

[0252] The particle sizes of asphalt in the water to be treated and the treated water were measured by sieving the samples using a mesh sieve.

[0253] (3) Asphalt concentration

[0254] The asphalt concentration in the treated water and the treated water was measured as follows: the sample was sieved through a mesh sieve, and then Nile red (1.25 mg / L) was added to the sieved sample and the absorbance was measured using an AquaFluor handheld fluorometer (manufactured by TURNER DESIGNS). The standard curve was prepared by using a water-based EVA adhesive EL-105 (manufactured by REGITEX) as a standard product, and the concentration of EL-105 was prepared in the range of 0 to 250 mg / L.

[0255] (4) Ash content

[0256] The ash content in the water to be treated and the treated water was measured in accordance with JIS K0102.

[0257] (5) SS absolute dry quality

[0258] The absolute dry mass of SS in the treated water and the treated water is the mass of the sample after it is dried in a dryer at a temperature of 105±5℃ to a constant mass, and then cooled and humidified in a room with the room temperature adjusted to 23℃ and the humidity adjusted to 50%.

[0259] (6) pH

[0260] The pH (40° C.) of the treated water and the treated water was measured using a general pH meter (for example, “Portable pH Meter D-54 (pH / mV(ORP) / COND / Resistivity / Salinity / TDS)” manufactured by Horiba, Ltd. or its successor models).

[0261] (7) Pulp concentration (pulp weight)

[0262] The pulp concentration (pulp weight) (mg / L) in the treated water and the treated water was calculated according to "pulp weight + ash weight + pitch weight = suspended matter concentration (SS weight)".

[0263] (8) Bitumen concentration and selective concentration ratio of asphalt in foam

[0264] Regarding the asphalt removal effect, the asphalt concentration and the selective concentration ratio of asphalt in the foam were calculated from the ratio of the SS concentration removed in the foam and the asphalt using the following (Formula 2) and (Formula 3).

[0265] (Formula 2) Asphalt concentration = (Asphalt concentration in the filtrate after 425 μm filtration) - (Asphalt concentration in the filtrate after 20 μm filtration)

[0266] (Equation 3) Selective concentration ratio of asphalt in foam = (Asphalt concentration in foam / Asphalt concentration in raw water) / (SS concentration in foam / SS concentration in raw water)

[0267] More details are as follows.

[0268] The test slurries of Examples 1 to 5 and Comparative Examples 1 to 2 were prepared by dissociating unused corrugated paper purchased with tap water in a manner such that the suspended solids (SS) concentration became a predetermined concentration. At this time, the slurries were prepared in a manner such that the Canadian standard freeness became 300 mL. These were used as test slurries (at a SS concentration of 1%, a pH of 6.5 (water temperature of 40° C.)).

[0269] Each test slurry (Examples 1 to 5 and Comparative Examples 1 to 2) adjusted to 40°C was prepared to obtain the suspended matter concentration shown in Table 2, and these were used as each sample. It should be noted that, regarding the test slurries adjusted to 40°C of Examples 4 and 5, asphalt removal chemicals A and B were added to the sample water in a concentration of 1.4 mg / L before flotation.

[0270] For each sample, a small table flotation device (MT-5L manufactured by Ishikawajima Sangyo Co., Ltd.) was used, and the air volume (air) was set to 6 L / min to generate bubbles (bubble diameter was 1 to 2 mm), and flotation was performed for 3 minutes while generating horizontal convection under moderate stirring conditions (rotation speed equivalent to 3800 rpm). The small table flotation device is a device that breaks basic bubbles into bubbles of 1 to 2 mm by contacting them with a high-speed rotating turbine, aerating them in 360-degree directions, and stirring that generates horizontal convection.

[0271] The scraper attached to the small table-top flotation device was moved near the water surface every 30 seconds to recover the scraped material as froth.

[0272] The asphalt removal chemicals used are summarized in Table 1. The number average molecular weight and HLB value in Table 1 can be calculated by the method described in <1-3-3. Additives> above.

[0273] [Table 1]

[0274] Table 1 List of asphalt removal chemicals

[0275] Drug Name composition Number average molecular weight HLB value Drug A Esterified polyethylene glycol 400 11.8 Drug B Esterified polyethylene glycol 600 13.7

[0276] Thereafter, the SS concentration contained in the foam recovered by the flotation treatment was measured in accordance with JIS K0102. In addition, regarding the bitumen concentration in the foam, Nile red was added to the filtrate when filtering through a sieve with a mesh size of 425 μm or 20 μm so that the concentration became 1.25 mg / L, and the absorbance was measured using an AquaFluor handheld fluorometer (manufactured by TURNER DESIGNS).

[0277] The asphalt removal effect is determined based on the ratio of the SS concentration removed in the foam to the asphalt. The selective concentration ratio of the asphalt in the foam is determined based on the above-mentioned "(7) Asphalt concentration and selective concentration ratio of asphalt in the foam".

[0278] Table 2 summarizes the results of Examples 1 to 5 and Comparative Examples 1 to 2.

[0279] <Results>

[0280] The present inventors found that, as in Examples 1 to 5, when flotation was used, when the SS concentration of the raw water was 0.5% or more, the asphalt in the foam showed a higher concentration ratio than that of SS. This means that the asphalt was selectively adsorbed to the foam and was floated and separated compared to SS. As in Comparative Examples 1 to 2, if the SS concentration of the raw water changed from 0.1% to 0.2%, the concentration ratio decreased, but as in Examples 1 to 5, if the SS concentration of the raw water changed to 0.5% or more, the concentration ratio reversed and increased sharply. The present inventors found that the asphalt at this time had a relatively large particle size of 20 μm or more and 425 μm or less, and therefore, it was possible to more efficiently remove asphalt from water containing asphalt having large particle size asphalt.

[0281] Furthermore, the inventors found that Example 4 in which Chemical A was used in combination showed a higher asphalt concentration ratio than Example 5. Therefore, by combining a chemical with a low HLB value (HLB value is preferably 12 or less), i.e., high hydrophobicity, with flotation, the concentration effect can be further improved.

[0282] [Table 2]

[0283]

[0284] Description of Reference Numerals

[0285] 1: Papermaking process, 10: Raw materials, 2: Preparation process, 21: Dissolution process, 22: Dissociation process, 23: Dust removal process (cleaner process, screen process), 24: Concentration process, 25: Beating process, 3: Papermaking process, 31: Dust removal process, 32: Paper layer forming process, 33: Wet paper dehydration process, 34: Wet paper drying process, 4: Water recovery process, 41: Primary circulation water process, 42: Secondary circulation water process, 43: White water, 5: Paper, 6: Drainage, 100: Processing process (asphalt removal process) or device for treating water containing asphalt according to the present embodiment

Claims

1. A method for treating water containing asphalt, characterized in that: This is a method for treating water containing asphalt in a papermaking process. The treated water containing asphalt in the papermaking process is treated water containing asphalt with a particle size of 20 μm or more after screen treatment, or is treated water containing asphalt with a particle size of 20 μm or more selected from one or more of the preparation process, papermaking process and water recovery process, which is treated water containing asphalt after screen treatment and reused. The treated water contains pulp and the concentration of suspended matter is above 0.3%. At pH 5 to 10, bubbles are generated by aeration in treated water containing asphalt to which a nonionic surfactant having an HLB value of 12 or less is further added to the treated water other than the treated water in the deinking process, and foam formed by the asphalt in the treated water adhering to the bubbles is removed, thereby removing asphalt with a particle size of 20 μm or more from the treated water other than the treated water in the deinking process.

2. The method for treating asphalt-containing water according to claim 1, wherein: The selective concentration ratio of bitumen in the foam is set to 3 or more.

3. The method for treating asphalt-containing water according to claim 1 or 2, wherein: The nonionic surfactant is a polyalkylene glycol.

4. The method for treating asphalt-containing water according to claim 3, wherein: The polyalkylene glycol is a polyalkylene glycol having a hydrophobic group and a number average molecular weight of 300 or more and 1000 or less.

5. The method for treating asphalt-containing water according to claim 1 or 2, wherein: The nonionic surfactant is esterified polyethylene glycol.

6. The method for treating asphalt-containing water according to claim 1 or 2, wherein: The nonionic surfactant is used in an amount of 0.5 mg / L or more and 10 mg / L or less.

7. The method for treating asphalt-containing water according to claim 1 or 2, wherein: The particle size of the asphalt is greater than or equal to 20 μm and less than or equal to 500 μm.

8. The method for treating asphalt-containing water according to claim 1 or 2, wherein: The particle size of the asphalt is greater than or equal to 20 μm and less than or equal to 425 μm.

9. The method for treating asphalt-containing water to be treated according to claim 1 or 2, wherein: The pulp concentration contained in the treated water containing asphalt is 3000-30000 mg / L.

10. The method for treating asphalt-containing water to be treated according to claim 1 or 2, wherein: The concentration of suspended matter in the treated water containing asphalt is 0.4-5%.

11. The method for treating asphalt-containing water to be treated according to claim 1 or 2, wherein: The aeration gas volume is greater than 0.5 L / min, and the bubble particle size is 1-3 mm.

12. The method for treating asphalt-containing water to be treated according to claim 1 or 2, wherein: The temperature of the treated water containing asphalt during aeration is 20-50°C.

13. A method for reducing asphalt having a particle size of 20 μm or more from asphalt-containing water to be treated, comprising the steps of: supplying air bubbles at a pH of 5 to 10 to asphalt-containing water other than water to be treated in a deinking process, which contains pulp in a papermaking process and has a suspended matter concentration of 0.3% or more, thereby removing asphalt having a particle size of 20 μm or more from the water to be treated, The treated water containing asphalt is treated water containing asphalt with a particle size of 20 μm or more after wire mesh treatment, or treated water containing asphalt with a particle size of 20 μm or more selected from one or more of a preparation step, a papermaking step and a water recovery step, which is treated water containing asphalt after wire mesh treatment and reused. A nonionic surfactant having an HLB value of 12 or less is added to the water to be treated to which the bubbles are supplied.

14. The method for reducing asphalt having a particle size of 20 μm or more from asphalt-containing water to be treated according to claim 13, wherein: The foam formed by the asphalt adhering to the air bubbles is removed.

15. The method for reducing asphalt having a particle size of 20 μm or more from asphalt-containing water to be treated according to claim 14, wherein: The selective concentration ratio of bitumen in the foam is set to 3 or more.

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