JP2009243016A - Pulp-cleaning agent and method for producing pulp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pulp-cleaning agent excellent in a function for removing organic matters from a pulp material, and to provide a method for producing pulp with the pulp-cleaning agent. <P>SOLUTION: The pulp-cleaning agent contains a nonionic surfactant having an aromatic ring in a hydrophobic portion. The method for producing the pulp has a digesting step of digesting the pulp material in a digesting zone 211 to obtain the pulp, a washing step of washing the pulp in a washing zone 212 or in a pulp-washing portion 30, and a bleaching step of bleaching the washed pulp in a bleaching portion, and further having an adding step of adding a pulp-washing agent containing a nonionic surfactant having an aromatic ring in a hydrophobic portion to the washing zone 212 or the pulp-washing portion 30. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a pulp cleaning agent for cleaning pulp and a method for producing the cleaned pulp.

  The pulp manufacturing process includes cooking procedures for cooking wood chips to obtain pulp, a cleaning procedure for separating the pulp and black liquor containing lignin, washing the separated pulp, and bleaching the washed pulp. Bleaching procedure (see, for example, Patent Document 1). The bleached pulp produced in this way is used for papermaking and the like.

  In a pulp cleaning system (including an oxygen delignification step), efficiently removing extracted components such as lignin from pulp greatly contributes to an improvement in process productivity. Until now, the washing efficiency of pulp has been improved mainly by improving the washing machine. However, since this requires a lot of cost, practical improvements using chemicals without remodeling are also being attempted. .

For example, as a chemical | medical agent which raises the washing | cleaning efficiency of a pulp, surfactant is mentioned, Among these, a nonionic surfactant is widely applied (for example, refer patent document 2).
Japanese Patent Publication No. 48-39963 JP 2003-161491 A

  However, the detergency of nonionic surfactants that have been widely applied conventionally is not satisfactory.

  Accordingly, the present invention provides a pulp containing a surfactant that has an excellent function of removing organic substances (soil components) such as lignin degradation products and resins adhering to the pulp, as compared with conventional nonionic surfactants. It is an object of the present invention to provide a cleaning agent and a pulp manufacturing method using the pulp cleaning agent.

  The pulp cleaning agent of the present invention is characterized by containing a nonionic surfactant having an aromatic ring in a hydrophobic portion.

  In the pulp cleaning agent of the present invention, the aromatic ring is preferably one benzene ring.

  In the pulp cleaning agent of this invention, it is preferable to further contain a builder.

  In the pulp cleaning agent of the present invention, the builder is preferably a chelating compound or a water-soluble polymer.

  The pulp production method of the present invention includes a cooking procedure for cooking pulp material in a cooking section to obtain pulp, a washing procedure for washing the pulp in a pulp washing system, and a bleaching procedure for bleaching the washed pulp in a bleaching section, The pulp cleaning system further includes an addition procedure for adding a pulp cleaning agent containing a nonionic surfactant having an aromatic ring in the hydrophobic portion.

  In the pulp manufacturing method of the present invention, the aromatic ring is preferably one benzene ring.

  In the pulp manufacturing method of the present invention, the pulp detergent preferably further contains a builder.

  In the pulp manufacturing method of the present invention, the builder is preferably a chelating compound or a water-soluble polymer.

  According to the present invention, since the non-ionic surfactant having an aromatic ring in the hydrophobic portion is contained in the pulp cleaning agent, the cleaning degree of the pulp cleaning agent is improved. This is because the structure of the hydrophobic part of the nonionic surfactant contained in the pulp cleaner is close to the structure of organic substances (dirt components) such as lignin degradation products and resins that are attached to the pulp. It is presumed that the affinity between the agent and the organic substance increased, and the organic substance was effectively solubilized.

  Hereinafter, although embodiment of this invention is described, this invention is not specifically limited to this.

[Pulp production system and pulp production method]
FIG. 1 is a block diagram showing an example of a pulp production system to which a cleaning agent according to the present invention is applied. The pulp production system 10 includes a digestion cleaning system 20, a pulp cleaning unit 30, and a bleaching unit in order from the upstream.

  The digester cleaning system 20 has a digester 21 in which the pulp material is digested and preliminarily cleaned. Specifically, in the cooking zone 211 of the digester 21, the non-fiber components in the wood chips are dissolved by mixing wood chips that are pulp materials and a solution containing sodium hydroxide or the like, and steaming under pressure. Then, preliminary cleaning is performed in the cleaning zone 212 of the digester 21. The pulp slurry obtained through the washing zone 212 and mixed with the black liquor in which the non-fiber components are dissolved and the pulp is transferred to the next pulp washing unit 30 through a blow tank (not shown). The cooking section of the present invention is constituted by the cooking zone 211, and the cooking procedure constituting the pulp manufacturing method of the present invention refers to the work up to the upstream of the washing zone 212.

  The pulp cleaning unit 30 separates and cleans the pulp from the pulp slurry. Specifically, the pulp slurry transferred from the digester 21 is introduced into the diffusion cleaning device 31, subjected to countercurrent cleaning, and then transferred to the knotter 32. The cooking liquor is subjected to replacement washing in the first pre-drum washing device 33 and the second pre-drum washing device 34 after the undistilled material remaining in the knotter 32 is removed. Thereby, the black liquor containing lignin is collect | recovered. Sodium hydroxide may be separated from the recovered black liquor and reused.

  Subsequently, the pulp after the black liquor is removed is heated to a predetermined temperature by being supplied with steam by the steam mixer 35 and then stored in a front storage tank (not shown). The pulp stored in the pre-storage tank is supplied with oxygen and then introduced into the oxygen reactor 36 where further delignification is performed. The pulp discharged from the oxygen reactor 36 is transferred to a blow tank 37 and introduced into a first rear drum cleaning device 38 and a second rear drum cleaning device 39. In the first post-drum cleaning device 38 and the second post-drum cleaning device 39, the pulp is further cleaned and lignin and the like are removed. Pulp from the second post-drum cleaning device 39 is stored in a post-storage tank (not shown) and then transferred to the bleaching section. The pulp washing system of the present invention is constituted by the washing zone 212 and the pulp washing unit 30, and the washing procedure constituting the pulp manufacturing method of the present invention refers to the operation from the washing zone 212 to the upstream of the bleaching unit.

  Subsequently, the pulp is bleached in the bleaching section to produce a high-quality pulp that is preferably used for papermaking. A bleaching part and the bleaching agent used may be a conventionally well-known thing. The above is an example of the bleaching procedure which comprises the pulp manufacturing method of this invention.

  As described above, in the pulp washing system including the oxygen delignification step (washing zone 212 and pulp washing unit 30), efficiently removing extracted components such as lignin from the pulp greatly contributes to the improvement of process productivity. To do.

  The pulp manufacturing method of the present invention further includes an addition procedure for adding the pulp cleaning agent of the present invention to the washing zone 212 and the pulp washing unit 30 in addition to the cooking procedure, the washing procedure, and the bleaching procedure, thereby improving the productivity of the process. Improve. The pulp cleaner used in the present invention will be described below.

[Pulp cleaning agent]
The pulp cleaner of the present invention contains a nonionic surfactant having an aromatic ring in the hydrophobic portion. In the pulp cleaning agent of the present invention, the content of the nonionic surfactant is not particularly limited. For example, it may be an amount that affects the removal of organic substances (dirt components) such as lignin degradation products and resins adhering to the pulp, and may vary depending on the type and amount of the builder described later. Depending on the type of the pulp, the degree of the organic matter adhering thereto, the washing conditions, etc., it may be set appropriately.

  The nonionic surfactant used in the present invention is not particularly limited as long as it has an aromatic ring in the hydrophobic portion. In the present invention, the aromatic ring may be a benzene ring or a naphthalene ring, but a benzene ring is more preferable. The number of aromatic rings is not particularly limited, but those having one benzene ring are excellent in detergency to remove organic substances (dirt components) such as lignin degradation products and resins adhering to the pulp. It is preferable in that it is. The nonionic surfactant used in the present invention may have an aromatic ring in its main chain or a side chain, but the main chain is more preferable. Examples of the nonionic surfactant used in the present invention include polyoxyalkylene aryl ether and polyoxyalkylene styrenated aryl ether. Here, the number of carbon atoms of the alkylene is preferably 1 to 3, and more preferably 2. Examples of aryl include a phenyl group and a naphthyl group, and a phenyl group is more preferable. The presence or absence of a substituent is not particularly limited. Specific examples include polyoxyethylene phenyl ether, polyoxyethylene styrenated phenyl ether, polyoxyethylene naphthyl ether, and the like. In order to solubilize and remove organic matter from the pulp, it is presumed that the structure of the organic matter and the hydrophobic portion of the nonionic surfactant are close to each other and preferably have a high affinity.

  The pulp cleaner of the present invention preferably further contains a builder. A builder is an inorganic compounding agent (cleaning aid) that increases the cleaning effect of a surfactant, and is not limited to what is generally referred to as a builder, and may be a compound having a builder function. Preferable examples include a chelating compound having a function of complexing a metal, a water-soluble polymer, and the like. In the pulp cleaning agent of the present invention, the builder content is not particularly limited. For example, it is sufficient that the lignin extraction is not hindered by calcium contained in a large amount in the liquid flowing through the washing zone 212 and the pulp washing unit 30, and may be set as appropriate according to the situation.

  Examples of the builder used in the present invention include ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), hydroxyethylenediaminetetraacetic acid (HEDTA), ethylenediaminesuccinic acid (EDDS), triethylenetetraaminehexaacetic acid (TTHA), Chelating compounds such as hydroxyethanephosphonic acid (HEDP), nitrilotrismethylenephosphonic acid (NTMP), phosphonobutanetricarboxylic acid (PBTC), diethylenetriaminepentamethylenephosphonic acid (DTPMPA), and polyacrylic acid (AA), acrylic acid And 2-hydroxy-3-allyloxy-1-propanesulfonic acid (AA / HAPS), acrylic acid and methyl acrylate copolymer (AA / MA), methyl acrylate and iso Copolymers of styrene (MA / IB), and include water-soluble polymers such as a copolymer of methyl acrylate and of acrylic acid and vinyl acetate. These may be used individually by 1 type and may be used together by multiple types.

  In the pulp manufacturing method of the present invention, the pulp cleaning agent may be added to one or a plurality of locations in the cleaning zone 212 and the pulp cleaning section 30, or the same location or every component such as a nonionic surfactant and a builder. You may add to another location.

[Evaluation of cleaning agent 1]
<Control Zone>
10 g of a pulp sheet (pulp concentration: about 14 mass% to about 30 mass%) at the outlet of the cleaning device 38 was collected. This was dispersed in 300 ml of a 0.002 mass% calcium aqueous solution (20 mg of calcium (manufactured by Wako Pure Chemical Industries, Ltd. dissolved in 1 L of distilled water: actual washing water level)) in a water bath at 60 ° C. for 5 minutes. The solution was stirred (hereinafter, this solution is referred to as Solution 1). Next, after leaving the solution 1 to stand for 5 minutes, a part of the supernatant was collected, and the filtrate filtered through a 0.45 μm filter was used as a blank 1. On the other hand, the solution 1 was further stirred for 15 minutes while being kept at 60 ° C., and then allowed to stand for 5 minutes, and then a part of the supernatant was collected, and the filtrate filtered through a 0.45 μm filter was designated as blank 2. And what subtracted TOC of blank 1 from TOC (total organic carbon) of blank 2 was made into the increase in the amount of TOC in a control section. The TOC was measured using a TOC meter (total organic carbon meter: manufactured by Shimadzu Corporation).

<Example 1>
To the solution 1 prepared by the above method, a detergent containing 1% by mass of a nonionic surfactant having an aromatic ring in the hydrophobic portion of the present invention was added to 50 mg / L, and the same as in the control group The TOC was measured by the operation.

<Examples 2 to 7>
To the solution 1 prepared by the above method, a detergent prepared so that the nonionic surfactant having an aromatic ring in the hydrophobic portion of the present invention and the builder have the prescribed concentrations shown in Table 1 was added, and the control group TOC was measured by the same operation.

<Comparative Examples 1-3>
To the solution 1 prepared by the above method, a nonionic surfactant that does not have an aromatic ring in the hydrophobic part and a cleaning agent prepared so that the builder has a specified concentration shown in Table 1 are added, TOC was measured by the same operation.

<Comparative Examples 4 and 5>
To the solution 1 prepared by the above method, a cleaning agent prepared so that the builder had the specified concentration shown in Table 1 was added, and the TOC was measured by the same operation as in the control group.

  These results are shown in Table 1. The composition and specified concentration of the added pulp cleaning agent are as shown in Table 1. For comparison, the TOC was corrected after measuring the value of the cleaning agent in advance.

The pulp cleaning agents of the present invention (Examples 1 to 7) all showed a good TOC increase rate. Moreover, the pulp cleaning agent of the present invention (Examples 2, 4 and 6) has a higher TOC than the pulp cleaning agent (Comparative Examples 1, 2 and 3) containing a nonionic surfactant having no aromatic ring. The rate was high. From this, it was found that the pulp cleaning agent of the present invention exhibits an excellent cleaning effect as compared with a pulp cleaning agent containing a nonionic surfactant having no aromatic ring.
The pulp detergent of the present invention containing the builder (Examples 2 to 7) had a very high TOC increase rate compared to the pulp detergent of the present invention not containing the builder. From this, it was found that the detergency was further increased by further containing a builder.
In addition, the pulp cleaner of the present invention containing POE phenyl ether having a benzene ring (Examples 2 and 3) is the pulp cleaner of the present invention containing POE naphthyl ether having a naphthalene ring (Examples 6 and 7). The TOC increase rate was higher than that. From this, it was found that the pulp cleaning effect was higher when a nonionic surfactant having a benzene ring was contained than a naphthalene ring.
Further, the pulp cleaning agent of the present invention containing POE styrenated phenyl ether having two benzene rings (Examples 4 and 5) is a pulp cleaning of the present invention containing POE phenyl ether having one benzene ring. The TOC increase rate was lower than the agent (Examples 2 and 3). From this, it was found that the pulp cleaning effect was higher when a nonionic surfactant having one benzene ring was contained rather than having two benzene rings.

[Evaluation of cleaning agent 2]
<Examples 8 and 9>
To the solution 1 prepared by the evaluation method 1 of the above-mentioned cleaning agent, the cleaning agent prepared so that the nonionic surfactant having an aromatic ring in the hydrophobic portion and the builder in the hydrophobic part of the present invention have the prescribed concentrations shown in Table 2. The TOC was measured by the same operation as in the control group of Evaluation Method 1.

<Comparative Examples 6-11>
To the solution 1 prepared by the above-described cleaning agent evaluation method 1, the cleaning agent prepared so that the nonionic surfactant having no aromatic ring in the hydrophobic portion and the builder have the prescribed concentrations shown in Table 2 is added. Then, the TOC was measured by the same operation as that in the control section of the evaluation method 1.

  These results are shown in Table 2. In addition, the composition and specified concentration of the added pulp cleaning agent are as shown in Table 2. For comparison, the TOC was corrected after measuring the value of the cleaning agent in advance.

  The pulp cleaning agent of the present invention containing builder (Examples 8 and 9) is a nonionic surfactant-containing pulp cleaning agent (Comparative Examples 6 to 11) that similarly contains a builder and does not have an aromatic ring. In comparison, the rate of increase in TOC was high. From this, it is considered that the pulp cleaning agent improves the detergency by containing a nonionic surfactant having an aromatic ring.

It is a block diagram which shows an example of the pulp manufacturing system with which the cleaning agent which concerns on this invention is applied.

Explanation of symbols

10 Pulp production system 20 Cooking cleaning system 211 Cooking zone (cooking part)
212 Washing zone (pulp washing system)
30 Pulp washing section (pulp washing system)

Claims (8)

  A pulp cleaner comprising a nonionic surfactant having an aromatic ring in a hydrophobic portion.   The pulp cleaner according to claim 1, wherein the aromatic ring is one benzene ring.   The pulp cleaning agent according to claim 1 or 2, further comprising a builder.   The pulp builder according to claim 3, wherein the builder is a chelating compound or a water-soluble polymer. A pulp production method comprising: a cooking procedure for cooking pulp material in a cooking section to obtain pulp; a washing procedure for washing the pulp in a pulp washing system; and a bleaching procedure for bleaching the washed pulp in a bleaching section. And
The pulp manufacturing method which further has the addition procedure which adds the pulp cleaning agent containing the nonionic surfactant which has an aromatic ring in a hydrophobic part to the said pulp cleaning system.   The pulp manufacturing method according to claim 5, wherein the aromatic ring is one benzene ring.   The pulp manufacturing method according to claim 5 or 6, wherein the pulp cleaning agent further contains a builder.   The pulp builder according to claim 7, wherein the builder is a chelating compound or a water-soluble polymer.

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