JP2543214B2 - Cleaning agent and cleaning method for paper / pulp manufacturing process - Google Patents

Description

TECHNICAL FIELD The present invention relates to a cleaning agent and a cleaning method for a paper / pulp manufacturing process in a paper / pulp mill, and particularly to a member in a water system of the paper / pulp manufacturing process, The present invention relates to a cleaning agent and a cleaning method that can easily remove and disperse sludge-like dirt that often adheres to the surface of a wall material and causes various troubles outside the system.

(B) Conventional technology In the paper / pulp manufacturing process, sludge-like dirt adheres to and accumulates on members and wall materials in the process water system, especially wire pit wall materials and pipeline surfaces, causing various obstacles. cause.

Contamination that adheres and accumulates in the water system of the paper / pulp manufacturing process, pitch components from virgin pulp, fine fibers, printing ink from waste paper, clay as a filler,
Rosin size as a sizing agent, such as diatomaceous earth, talc, calcium carbonate, calcium sulfate, barium sulfate,
Alkyl ketene dimer, alkenyl succinic anhydride, sulfuric acid band, polyacrylic resin as paper strengthening agent, urea formaldehyde resin, melamine-formaldehyde resin, starch, cationized starch, etc., and metals such as iron, calcium, magnesium etc. from water. It has a complex composition consisting of salts, slimes due to bacteria, mold, etc., and due to the peculiarities of the components derived from it, sludge-like stains that occur in ordinary industrial water systems such as general cooling water systems are components, properties, etc. Is very different. However, since it directly contacts and mixes with the paper or pulp material that is the product,
It causes serious obstacles such as deterioration of product quality and reduction of production efficiency, and this problem has become serious with the recent closure of paper / pulp manufacturing process and increase of papermaking speed.

Therefore, conventionally, a cleaning process for removing sludge-like dirt from the system by separating and separating it at regular intervals has been performed, and as a specific cleaning method, for example, cleaning with various surfactants,
It is known to perform acid cleaning with hydrochloric acid, sulfuric acid, sulfamic acid, etc., alkali cleaning with soda ash, caustic soda, etc., cleaning with organic solvents such as kerosene, light oil, xylene and chlorine-based solvent. Further, recently, cleaning using an acrylic acid-based polymer has also been proposed (JP-A-62-21893).

(C) Problems to be Solved by the Invention However, among the conventional cleaning methods, cleaning with various surfactants has almost no effect on sticky sludge containing polyvalent metal salts because foaming easily occurs during use. There is no. Acid cleaning is highly corrosive to metals and cannot be practically used. Cleaning with an organic solvent requires careful attention to fire and toxic gas and is restricted in handling.

Therefore, conventionally, alkali cleaning has been generally used in such a system, but its cleaning effect is not sufficiently satisfactory, and especially sludge containing a large amount of metal salts such as silica and magnesium, and paper. The sludge containing cationized starch, which has been widely used recently as a force-enhancing agent, has an insufficient cleaning effect and requires a long cleaning time and manual work.

Further, even in the above-mentioned washing method using an acrylic acid-based polymer (JP-A-62-21893), the washing effect of sludge containing the above metal salts and cationized starch was insufficient.

The present invention has been made under such circumstances, and in particular, it is excellent in cleaning effect and can be efficiently removed in a short time even with difficult-to-release sludge containing metal salts or cationized starch as a constituent component as described above. An agent and a cleaning method are provided.

In addition, a part of the organic phosphonic acids used in the present invention,
It is known that it has an effect of dissolving and removing scale generated on the inner surface of a boiler or a heat exchanger based on its chelating action (Japanese Patent Laid-Open No. 51-9029). However, it is not known to be used for peeling and removing sludge in a paper / pulp manufacturing process, and in particular, it is completely known to have a remarkable effect in the use of peeling and dispersing and removing it outside the system, not by dissolving and removing. Absent.

(D) Means for Solving the Problems Thus, according to the present invention, the following general formula (I): [In the formula, A represents a divalent lower hydrocarbon group which may be substituted with a hydroxyl group or an amino group, or a divalent group represented by the following formula: CH ₂ —NX—CH _{2 1} CH _{2 m} CH ₂ -NX-CH _{2 n (wherein,} X represents a phosphono-lower alkyl group, l + n is m is an integer of 0 to 4 1 to 3) containing as organic phosphonic acids or a salt thereof as an active ingredient represented by] A cleaning agent for a paper / pulp manufacturing process is provided.

Further, according to the present invention, a cleaning method in a paper / pulp manufacturing process using the organic phosphonic acid of the above formula (I) or a salt thereof is proposed.

This invention is a paper / organic phosphonic acid of formula (I)
By adding and circulating the water in the pulp manufacturing process,
It is based on the discovery of the fact that the above-mentioned difficult-to-separate sludge is efficiently separated and dispersed, and can be easily removed from the system. The above organic phosphonic acids are conventionally known as compounds having a chelating action, but other known chelating agents such as EDTA, 2-phosphono-butane-1,2,4-tricarboxylic acid, and tripolyphosphoric acid. Even if sodium or the like is used, the above effects cannot be obtained. Therefore,
The cleaning effect exhibited by this invention is unique to the organic phosphonic acid of formula (I).

In the organic phosphonic acid of the formula (I) of the present invention, the lower hydrocarbon group and the lower alkyl group mean a hydrocarbon group and an alkyl group having 1 to 4 carbon atoms, for example, methylene,
Examples include ethylene, propylene, trimethylene and tetramethylene groups and methyl, ethyl, propyl and butyl groups. Specific examples of the organic phosphonic acid include 1-hydroxyethylidene-1,1-diphosphonic acid, ethylenediaminetetra (methylenephosphonic acid), hexamethylenediamineethra (methylenephosphonic acid), diethylenetriaminepenta (methylenephosphonic acid), nitrilotrimethylphosphonic acid. Acid etc. are mentioned.

Among these, 1-hydroxyethylidene-1,1-diphosphonic acid, nitrilotrimethylphosphonic acid or ethylenediaminetetra (methylenephosphonic acid) is preferably used from the viewpoint of easy availability. Further, as these salts, easily water-soluble salts are used, and alkali metal salts are suitable,
It is preferable to use potassium salt or sodium salt. Of course, these compounds and salts may be mixed and used.

Cleaning of the paper / pulp manufacturing process in this invention
It can be carried out by circulating the wash water to which the above-mentioned organic phosphonic acid or a salt thereof is added, in the pulp manufacturing process system. More specifically, after removing water in the paper / pulp manufacturing step, by circulating wash water in which the organic phosphonic acid or a salt thereof is added and dissolved in water such as industrial water or tap water in this step system, It can be carried out. By such a treatment, sludge-like dirt adhering to the wall surface of the wire pit or pipeline is gradually peeled off from the wall surface and dispersed in the washing water during the paper / pulp manufacturing process system. The stains are almost completely removed from the wall surface and are dispersed in the wash water in the form of flocs. Then, by discharging this cleaning liquid out of the system, paper
Dirt in the pulp manufacturing process system is removed to the outside of the system.

When carrying out the cleaning method of the present invention, it is desirable that the cleaning water is alkaline in view of the cleaning effect, and especially pH 9
It is preferably set to 13 and, if necessary, caustic soda,
An alkaline agent such as caustic potash is used together. Furthermore, according to the knowledge of the present inventors, it has been found that a further excellent cleaning effect can be obtained by using hydrogen peroxide in combination with the above organic phosphonic acid or its salt. Therefore, according to the present invention, in addition to the above organic phosphonic acid or a salt thereof, hydrogen peroxide or a hydrogen peroxide generator (for example, a substance that releases hydrogen peroxide in water, for example, an inorganic substance such as perboric acid or percarbonic acid) is used. There is also provided a washing method comprising using washing water to which a peracid or a salt thereof or an organic peracid such as peracetic acid or a salt thereof is added in combination.

In the present invention, the concentration of the organic phosphonic acid or salt thereof in the wash water is not particularly limited and is usually 0.06 to 60.
It is preferably selected within the range of 0.1% by weight, and is preferably 0.1 to 5% by weight in terms of cost and cleaning effect. When hydrogen peroxide is used in combination, the concentration of H ₂ O ₂ can be selected in the range of 1/250 to 600 times the organic phosphonic acid.
A concentration of 1/20 to 50 times is suitable. Further, the washing time, that is, the flowing time of washing water is a time at which sludge-like dirt adhering to the inside of the system can be sufficiently separated and dispersed in the form of flocs, and it varies depending on the dirt adhering state, etc.
Six hours is sufficient, and when hydrogen peroxide is used in combination, this required time can be further shortened. In any case, the cleaning process can be performed in a shorter time than the conventional cleaning method, and the dirt that is difficult to remove can be removed. In addition,
The washing is usually carried out at room temperature, but it may be carried out by heating if necessary, whereby the washing time can be further shortened.

The cleaning liquid in the cleaning method of the present invention can be prepared by directly adding the above-mentioned organic phosphonic acids and, if necessary, an alkaline agent or hydrogen peroxide, and a liquid agent in which these are concentrated and dissolved or dispersed in water in advance. It is preferable to use it because it is easy to handle. At this time, in this liquid agent, other additives such as those that do not impair the effects of the present invention, for example,
A surfactant or a chelating agent may be blended.

(E) Example Multiple stainless steel test peat (300 x 100 x 1.5 mm) on the wall of the wire pit of a certain paper mill (printing paper manufacturing)
Papermaking (using talc as a filler and bansulphate soil with cationized starch as a paper-strengthening agent) was performed in a state of being hung. As a result, after one week, sludge-like dirt was strongly adhered to the surface of each test piece (average adhered amount 16 mg / cm ² ).

Table 1 shows the results of collecting these test pieces and examining the composition of the stains.

Table 1 Loss on ignition 30.8 (% by weight) SiO ₂ (from filler) 39.8 CaO (from filler) 0.7 MgO (from filler) 20.5 Al ₂ O ₃ (iodine starch reaction positive) 7.5 Prescribe test pieces with such stains Immersed in the cleaning liquid (40 ° C constant temperature) and stirring the cleaning liquid,
As a general rule, the state of peeling of dirt on the surface after 4 hours was examined.

The results are shown in Table 2 together with the cleaning liquid composition used and the ratio of the peeled area. In the table, A of compound (I) is 1-hydroxyethylidene-1,1-diphosphonic acid, B is nitrilotrimethylphosphonic acid, and C is ethylenediamineethra (methylenephosphonic acid). All percentages are percentages by weight.

As is clear from the above table, the peeling rate is 5% even if a cleaning solution using sodium hydroxide or hydrogen peroxide is used.
It was not enough (Comparative Examples 1 and 2), and the improvement of the peeling effect was not observed even when the chelating agent such as EDTA, sodium tripolyphosphate and PBTC was used in combination.

On the other hand, when the organic phosphonic acid of the compound (I) is used, an excellent peeling effect can be obtained by itself (Example 1), and the alkalinity improves the peeling effect (Examples 2 to 2). 4), it is understood that a more excellent peeling effect is achieved by using together with hydrogen peroxide.

(F) Effects of the Invention According to the cleaning agent and the cleaning method of the present invention, sludge-like dirt specifically generated in the paper / pulp manufacturing process can be efficiently peeled and removed, and in particular, the conventional substantially peeled It is possible to remove the sludge-like dirt, which was difficult to remove and was forced to be removed manually, in a short time.

Therefore, the cleaning agent and cleaning method of the present invention are extremely useful in the paper / pulp manufacturing process.

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Claims (3)

(57) [Claims] 1. The following general formula (I): [In the formula, A represents a divalent lower hydrocarbon group which may be substituted with a hydroxyl group or an amino group, or a divalent group represented by the following formula: CH ₂ —NX—CH _{2 1} CH _{2 m} CH ₂ -NX-CH _{2 n} (wherein, X represents a phosphono lower alkyl group, l + n is 1 to 3 and m is an integer of 0 to 4)] and hydrogen peroxide Or paper containing a hydrogen peroxide generator as an active ingredient
Cleaning agent for pulp manufacturing process. 2. In the paper / pulp manufacturing process system, the following general formula (I): [In the formula, A represents a divalent lower hydrocarbon group which may be substituted with a hydroxyl group or an amino group, or a divalent group represented by the following formula: CH ₂ —NX—CH _{2 1} CH _{2 m} CH ₂ -NX-CH _{2 n} (wherein X represents a phosphono lower alkyl group, l + n is 1 to 3 and m is an integer of 0 to 4)] and hydrogen peroxide Alternatively, a cleaning water in which a hydrogen peroxide generator is added is circulated to remove sludge adhering to the paper / pulp manufacturing process system by peeling and removing the sludge. 3. The cleaning method according to claim 2, wherein the cleaning water is alkaline.