JP2008264615A - Slime control agent addition method and device used therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new slime control agent addition method which can improve various problems occurring when the conventional organic slime control agent is continuously supplied to liquid to be treated, exhibit strong sterilization effect or inhibition effect to microorganisms in a liquid to be treated, such as white water, and easily and efficiently perform control of conditions according to the liquidity of the liquid to be treated. <P>SOLUTION: In a method for adding a slime control agent consisting a mixture of a hydantoin compound, ammonium halide, a hypohalous acid salt, and an alkaline aqueous solution to liquid to be treated, (A) a first liquid consisting of an aqueous solution of a hypohalous acid salt is diluted and its temperature is maintained at 5-35°C, and a second liquid consisting of ammonium halide or a mixture of ammonium halide, a hypohalous acid salt, and an alkaline aqueous solution is mixed therein without dilution to be poured into the liquid to be treated, and (B) after mixing the first liquid and second liquid, the mixture is poured before its oxidation-reduction potential becomes 850 mV or more. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method of adding a slime control agent to white water so that the effect can be sufficiently exerted in papermaking and an apparatus used therefor.

In order to prevent microbial contamination of circulating water such as white water in the papermaking process, a slime control agent is usually added.
As a slime control agent and a method of using such a slime prevention agent, a slime prevention method (patented so far) applies voltage to an electrode immersed in cooling water in the presence of a water-soluble polymer to generate an oxidizing agent from chloride ions in the water. Reference 1), an oxidizing agent such as chlorine gas, hypochlorous acid or a salt thereof was added to a reaction product of a bromine source such as hydrobromic acid, bromine chloride, bromine or alkali bromide with amines. Then, saccharin is added to a stabilized bromine solution (see Patent Document 2) whose pH is adjusted to at least 13 with alkali, an alkali bromide or alkaline earth metal bromide, and an alkali bromate or alkaline earth bromate metal. , Benzenesulfonamide, urea, added with a halogen stabilizer such as alkylhydantoin (see Patent Document 3), chlorinated oxidant, sulfamine oxidation compound And a composition for preventing slime containing an anionic polymer or a phosphonic acid compound (see Patent Document 4), a hypochlorite of an alkali metal or an alkaline earth metal is stabilized with a stabilizer and an alkali, and a bromide ion source is added. Inorganic oxidant systems such as biocides (see Patent Document 5), stabilized bromine solutions (see Patent Document 6) in which an oxidizing agent is added to a mixture of hydrobromic acid or an alkaline earth metal salt thereof and a stabilizer. Things have been proposed.

  However, such an inorganic oxide slime control agent has an excellent effect on microorganisms, but the effect is influenced by the influence of COD and SS. The effectiveness is reduced by the presence of a reducing substance. It has a good sterilization effect, has no sterilization effect, has no inhibitory effect, causes discoloration and fading of papermaking materials and fillers, has scale trouble, generates chlorine gas, detracts from health, has a fast decomposition and has a fast lifetime Have shortcomings, strong metal corrosiveness, and skin irritation.

  For this reason, recently, an organic system in which hypochlorite as an oxidizing agent is combined with amine sources such as ammonium salts, organic amines, sulfamic acid, hydrazine, dimethylhydantoin, cyanuric acid, hexamethylenediamine, and ethanolamine. Slime control agents are getting attention.

  By the way, as described above, an organic slime control agent is produced by mixing an oxidant component and an amine component and reacting them. However, since the product is unstable and has a short lifetime, it can be used in situ during use. Each component must be mixed and immediately supplied to the liquid to be treated, such as white water.

  Therefore, prepare a dilute solution of the oxide component and a dilute solution of the amine component separately, weigh each periodically, and continuously pass through the first and second pipes to the third pipe. While supplying, a method of mixing and reacting at a predetermined ratio in the third pipe to produce an organic slime control agent and continuously injecting it into the liquid to be processed as soon as possible. (See Patent Document 7).

  However, according to this method, in order to ensure reproducibility and stability, the management of the concentration and temperature of each diluent is complicated, and each component is supplied as a diluent so that the reaction is long. There is a drawback that it takes time.

JP 2001-310187 A (Claims and others) Japanese translation of PCT publication No. 2002-540297 (Claims and others) JP-T-2002-543048 ((Claims and others)) International Publication No. 2003/96810 pamphlet (claims and others) JP 2005-519089 (Claims and others) JP-T-2004-536760 (Claims and others) JP 10-506835 A (claims and others)

  The present invention improves various problems associated with continuously supplying a conventional organic slime control agent to a liquid to be treated, and has a strong bactericidal effect on microorganisms in the liquid to be treated such as white water or It was made for the purpose of providing a novel slime control agent addition method and an apparatus used therefor that exhibit an inhibitory effect and can easily and efficiently manage conditions according to the liquid properties of the liquid to be treated. is there.

The present inventors have conducted various studies on a method for continuously supplying a slime control agent to a liquid to be treated under a condition that can be easily managed, and without reducing its effect. By using the control agent, we succeeded in realizing it.
That is, the present inventors first reacted with sodium hypochlorite instantly, exhibiting a strong bactericidal effect, exhibiting a buffering action as an auxiliary to active halogens, exhibiting a suppressive effect, A cure side of a novel slime control agent that combines the advantages of an organic slime control agent and an inorganic slime control agent has been developed (Japanese Patent Application No. 2005-297017), but this slime control agent is conventionally known. It is found that a sodium hypochlorite-containing diluent and an ammonium bromide-containing diluent are prepared separately, and the disadvantages in the method of adding these diluents to each other after being mixed can be easily overcome. The present invention has been made based on this finding.

  That is, the present invention relates to a method of adding a slime control agent comprising a mixture of a hydantoin compound, ammonium halide, hypohalite and aqueous alkali solution to the liquid to be treated. The first liquid is diluted and kept at a temperature in the range of 5 to 35 ° C., and the second liquid composed of ammonium halide or a mixture of ammonium halide, hydantoin compound and aqueous alkali solution is mixed without dilution. A slime control agent that is added to the liquid to be treated, and (B) the first liquid and the second liquid are mixed and then added before the oxidation-reduction potential of the mixture becomes 850 mV or higher. Method of addition, mixer connected to the water storage tank through the flow meter by the water storage tank and the supply pipe, the mixer and the metering pump A hypohalite aqueous solution storage tank connected by a supply pipe, a hose through a control valve, a mixer and a hose through a control valve and a metering pump, ammonium halide or ammonium halide and a hydantoin compound, and A slime control agent supply hose having a mixing section connected to a storage tank for a mixture of alkaline aqueous solution and the amount of water from the storage tank, the amount of hypohalite aqueous solution from the hypohalite aqueous solution storage tank, ammonium halide or halogen A slime control agent continuous supply device comprising a control means for synchronously controlling the amount of a mixture of these components from a storage tank of a mixture of an ammonium fluoride and hydantoin compound and an aqueous alkaline solution Things .

The halite used in the method of the present invention acts as an oxidizing agent, and chlorous acid, bromous acid, alkali metal salts of iodic acid, such as sodium salt and potassium salt, are used. Sodium chlorite (NaClO) and sodium bromite (NaBrO) are preferred. Since this product is commercially available as a 15% by mass aqueous solution, it can be used as a stock solution as it is.
In the method of the present invention, this stock solution is diluted 30 to 100 times and used as the first solution.

  Next, as the ammonium halide, ammonium chloride or ammonium bromide is used, which is used as a source of bromine, and in the presence of a halite, monoclamine, dichloramine, trichloramine, monobromamine, It changes to dibromamine and tribromamine and shows bactericidal properties.

（式中のＲは、メチル基、エチル基、プロピル基のような低級アルキル基である）
で表わされる化合物であるが、好ましいのは、５，５‐ジメチルヒダントインである。このヒダントイン化合物は、微生物活性が失活するのを抑制する安定剤としての役割を果すと同時に、殺菌効果を高める作用を有する。第二液のもう１つの成分であるアルカリ水溶液としては、水酸化ナトリウム、水酸化カリウムのような水酸化アルカリ金属の水溶液が用いられる。 The hydantoin compound used in combination with the second liquid has the general formula

(R in the formula is a lower alkyl group such as a methyl group, an ethyl group, or a propyl group)
Of these, 5,5-dimethylhydantoin is preferred. This hydantoin compound serves as a stabilizer that suppresses the inactivation of microbial activity, and at the same time has an action of enhancing the bactericidal effect. As the alkaline aqueous solution which is another component of the second liquid, an aqueous solution of an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide is used.

  This second liquid is prepared as an aqueous solution having a solid concentration of 20 to 40% by mass, and is used as it is without dilution.

  In the method of the present invention, the water to be treated to which the slime control agent is added includes industrial water, industrial cooling water, various papermaking process waters, and white water during papermaking. This white water contains various paper-making aids such as recycled pulp and virgin pulp, fillers such as calcium carbonate, white carbon and talc, sulfate bands, sizing agents, paper strength agents, retention agents, and coagulants. It is added.

  Next, the method of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is an explanatory view of an apparatus suitable for carrying out the method of the present invention.

  This apparatus comprises a water storage tank 1, a supply pipe 2, a flow meter 3 through a flow meter 3, a mixer 4 connected to the water storage tank 1, and a mixer 4 connected to a supply pipe 6 through a metering pump 5. The aqueous acid salt solution storage tank 7 and the hose 8 are connected to the control valves 10-1, 10-2 and 10-3, and the mixer 4 and the hose 9 are used to control the valves 11-1, 11-2 and 11-3. It comprises a slime control agent supply hose 15 having a mixing section 14 connected to a storage tank 13 containing a mixture of ammonium halide and an aqueous alkali solution via a pump 12, and separately from each component, that is, water, hypoxia. Amount of aqueous halide salt, ammonium halide or a mixture of ammonium halide and hydantoin compound and aqueous alkaline solution And a control means for cyclically controlling (not shown).

In the mixing section 14 provided in the hoses 8 and 9 of this apparatus, ammonium halide or ammonium halide sent from the hose 9 is used for the first liquid made of a dilute aqueous solution of hypohalite sent from the hose 8. A second liquid obtained by mixing a hydantoin compound and an aqueous alkaline solution in advance is added without dilution, and the resultant slime control agent is poured into the liquid to be treated, for example, white water, before deactivation. The time that can be supplied from the mixing section to the liquid to be treated without being deactivated depends on the temperature of the hypohalite-containing diluted solution, and the time is short when the temperature is high, and the time is long when the temperature is low. For example, when the temperature of the diluent is 30 ° C., it is preferably added within 10 seconds. However, if the temperature of the diluent is 20 ° C., the reaction rate is slower than that at 30 ° C. The time may be longer than 10 seconds.
However, in order to obtain a stable effect, it is necessary to add it within 10 seconds, preferably within 5 seconds.

  Next, in order for the slime control agent added to the liquid to be treated by the method of the present invention to exhibit sufficient bactericidal and harmful microorganism generation inhibiting properties, its redox potential needs to be 850 mV or less. Yes, if it is higher than this, sufficient bactericidal properties and inhibitory effects on the generation of harmful microorganisms cannot be obtained.

  The use ratio of the first liquid and the second liquid in the present invention depends on the respective concentrations, the dilution ratio of the first liquid, the temperature, etc., but is 6: 1 to 1: 4, preferably 3: The molar ratio of the hypohalite to the ammonium halide is preferably 4: 1 to 1: 2, preferably 2: 1 to 1: 1.

  The content ratio of the ammonium halide and the hydantoin compound in the second liquid is in the range of 5: 1 to 1: 2 by mass ratio. When the amount of the hydantoin compound is less than this range, the harmful microorganism inhibitory ability is lowered, and when the amount of the hydantoin compound is larger than this range, the function of enhancing the bactericidal effect is lowered.

The amount of each component, first liquid and second liquid in the method of the present invention is controlled as follows, for example.
(1) The amount of water supplied from the water storage tank 1 to the mixer 4 is such that the electromagnetic ball valve provided between the two is closed and opened at the timer specified time, and the amount supplied to the hypohalous acid tank 7 and the mixer 4 The electromagnetic metering pump provided between the two is switched on and off to adjust the concentration and supply amount of the diluent.
The opening and closing of the electromagnetic ball valve and the switching of the electromagnetic metering pump are interlocked with a time lag of 1 to 2 minutes.

(2) The supply amount of the first liquid from the hose mixing unit 14 from the mixer 4 is controlled by opening and closing the electromagnetic valve 10 provided between users.

(3) The supply amount of the second liquid prepared in advance is controlled by the electromagnetic metering pump 12 and the electromagnetic valve 11 provided between the second liquid storage tank 13 and the mixing unit 14.

(4) The slime control agent prepared in the mixing unit 14 is added to white water within 10 seconds by adjusting the length of the hose to the mixing unit 14 and the supply port 15.
In addition, the opening / closing of the electromagnetic valve 10 and the time t until the mixing unit 14 in (2) can be determined according to the following equation.

t = L · S / V
L: Hose length
S: Hose cross-sectional area
V: Volume delivered per second

According to the method of the present invention, since the first liquid is used as a diluent and the second liquid is used as a stock solution, after mixing both, it can be added to the liquid to be treated in a short time, and the slime control agent is effective. Inactivation can be easily and effectively prevented.
Moreover, in the conventional method, the tank of the first liquid and the second liquid must be fixed and transferred from the place to the liquid to be treated by the hose, depending on the place of use of the tank of the second liquid. There is an advantage that it can be installed freely in the vicinity.

  Hereinafter, the best mode for carrying out the present invention will be described by way of examples, but the present invention is not limited thereto.

The examples were performed using the following method and apparatus.
Using the slime control agent adding device 20 shown in FIG. 2, the slime control agent is continuously added to the white water of the paper machine shown in FIG. 3 under various different conditions, and the occurrence of harmful microorganisms in the white water is examined. It was.
In this experiment, a dilute solution was used as a stock solution of an aqueous solution of sodium hypochlorite having a concentration of 12% by weight as the first solution, and an aqueous solution of ammonium bromide or ammonium bromide having a concentration of 30% by weight as the second solution. A 30% by weight aqueous solution having a mass ratio (NH ₄ Br: DMH = 4.3 / 1) to 5-dimethylhydantoin (hereinafter referred to as DMH) was used.

In the apparatus shown in FIG. 2, industrial water of 30 ° C. is poured into the main pipe 21, and sodium hypochlorite (NaOCl) is injected into the main pipe 21 from the first liquid supply section 22 through the first liquid supply pipe 23, and mixed. In the unit 26, after being mixed with NH ₄ Br or an aqueous solution containing NH ₄ Br and DMH fed from the second liquid supply unit 24 through the supply pipe 25, the slime control agent connected to the discharge side of the mixing unit 26 The white water main flow path 28 is added through the addition pipe 27. The adjustment valve 23A provided in the first liquid supply pipe 23 and the adjustment valve 25A provided in the second liquid supply pipe 25 are controlled by the addition control device 29.

  In FIG. 3, the paper machine 30 supplies the paper part raw water mixed with the raw material and the diluting water from the main flow path 28 to the wire part 31 for paper making using the wire, and the white water after the paper making is received by the drain pan 32. Then, after being stored in the white water tank 33, it is sent again to the main flow path 28 by the circulation pump 34 and is circulated as the papermaking raw water toward the wire part 31 together with the raw water supplied from the seed box 35. ing.

  Reference numeral 36 denotes a press part for pressing the paper squeezed by the wire part 31 with a roll to squeeze out moisture contained in the paper. 37 is provided in the middle of the main flow path 28 on the downstream side of the seed box 35, and is a decurator for vacuum degassing the papermaking raw material water, and 38 is a circulation pump for pumping the raw material water that has passed through the decurator 37. , 39 is a screen for filtering the papermaking raw material water, and 40 is an inlet for rectifying the papermaking raw water and supplying it to the wire part 31.

  Next, 41 is a drain pan for collecting white water squeezed in the press part, and 42 is a couch pit for collecting white water from the drain pan 41. The white water in the couch pit 42 is returned to the white water tank 33.

  Next, a process of adding the slime control agent from the slime control agent adding device 20 to the white water flowing through the white water tank 33 will be described.

  In this addition method, the first liquid is added to white water in an amount of 0.1 to 120 ppm [component concentration of 5 to 34% by mass], and the second liquid is added to 0.02 to 130 ppm.

  The main pipe 21 is made of an aqueous solution that flows industrial water and contains 10% by mass or more of the second liquid stored in the second liquid supply unit 24.

  The main pipe 21 is washed with about 100 liters in 2 minutes before and after the addition of the slime control agent, thereby washing the inside of the main pipe 21 to prevent the pipe from being rusted.

  In addition, the discoloration in each example, the number of viable bacteria in white water, and the bactericidal rate were evaluated by the following methods.

(1) Discoloration After mixing the first liquid and the second liquid, the state of the mixture after 5 seconds, 10 seconds, 15 seconds, and 30 seconds was visually observed and evaluated by the presence or absence of discoloration.

(2) Number of viable bacteria in white water The mixture after 5 seconds, 10 seconds, 15 seconds and 30 seconds after mixing is added to papermaking white water by pour plate culture, and 1 ml of papermaking white water is collected 15 minutes after addition. Then, the cells were cultured by an ordinary pour plate culture method using an SCD agar medium, and the viable water of papermaking white water was measured.

(3) Bactericidal rate The number of viable bacteria after adding the slime control agent was measured in the same manner as in (2) and calculated by the following calculation formula.

  Bactericidal rate (%) = (Blank viable count−Bacteria count in white water / Blank viable count) × 100

Reference example 1
An aqueous solution of sodium hypochlorite having a concentration of 12% by mass is used as a stock solution, and the first solution obtained by diluting this stock solution 30 times, 50 times and 100 times with diluting water having different liquid temperatures, ammonium bromide and DMH are in a mass ratio. About the mixture with the 30 mass% concentration aqueous solution (2nd liquid) contained by 4.3: 1, time (second) until oxidation-reduction potential (henceforth ORP) exceeds 850 mV was measured. The results are shown in Table 1.

  As can be seen from this table, when the dilution rate is 30 times, the ORP exceeds 850 mV after 9 seconds at 10 ° C. However, when the dilution rate is increased 100 times, the ORP exceeds 850 mV after 80 seconds. Thus, it turns out that the time over which ORP exceeds 850 mV can be adjusted by changing a dilution rate according to liquid temperature. Further, based on the time when the ORP exceeds 850 mV, the time from mixing the first liquid and the second liquid to adding to the target system (that is, the mixing position) is determined, and the dilution rate is adjusted by the liquid temperature. Thus, it is presumed that a slime control agent that is always effective can be added to the aqueous system.

A 12 mass% NaCl aqueous solution is quantified from the oxidizer supply unit 22 to the main pipe 21 in which industrial water having a water temperature of 30 ° C. flows at a rate of 50 liters per minute so that the NaCl concentration in the main pipe is 1.44 mass%. The pump 22A is adjusted and supplied. Moreover, it supplies to the mixing part 26 via the metering pump 25A from the 2nd liquid supply part 24 to the mixing part 26 so that mass ratio of a 1st liquid and a 2nd liquid may be set to 3: 1. FIG. 4 shows a graph showing the change over time of the OPR and sterilization rate of the mixture thus obtained, and FIG. 5 shows a graph showing the change over time of the pH value and the sterilization rate.
As can be seen from this figure, when 10 seconds or more have elapsed after mixing, the ORP increases rapidly, the pH value decreases rapidly, and the bacterial count reduction rate decreases.
Table 2 shows the number of viable bacteria, bactericidal rate, and discoloration in white water evaluated for this product.

As a second solution, NH ₄ mixture of Br and DMH instead of NH ₄ Br [mass ratio _{NH 4 Br: DMH = 4.3:} 1 ] used to produce a slime control agent in the same manner as in Example 1 The viable cell rate, bactericidal rate and discoloration in the white water were evaluated and shown in Table 2.

The same procedure as in Example 1 was performed except that a 15% by mass aqueous solution of DMH was used instead of NH ₄ Br as the second solution, and the mixing ratio was 2: 1 by mass ratio of the first and second solutions. The slime control agent was produced, and the viable cell count, bactericidal rate and discoloration in the white water were evaluated, and the results are shown in Table 2.

  A slime control agent was produced in the same manner as in Example 3 except that the mixing ratio of the first liquid and the second liquid in Example 3 was changed to 2: 1 by mass ratio, and added to white water. In this case, the number of viable bacteria in white water, the bactericidal rate and the discoloration were evaluated, and the results are shown in Table 2.

Examples 5-8
A slime control agent was produced in the same manner as in Examples 1 to 4 except that the temperature of industrial water was 20 ° C., and added to white water. In this case, the number of viable bacteria in white water, the bactericidal rate and the discoloration were evaluated and the results are shown in Table 3.

  Since the present invention shows a stable bactericidal effect regardless of the temperature change or pH change and dilution rate of industrial water used, it is possible to efficiently suppress the generation of harmful microorganisms in white water, and as a result, high Since quality paper can be obtained, it is useful in the papermaking process.

Explanatory drawing of an apparatus suitable for implementing this invention method. The block diagram which shows a slime control agent addition apparatus. Paper machine used in the examples. The graph which shows temporal change of ORP of the slime control agent obtained in Example 1, and a bactericidal rate. The graph which shows the time-dependent change of the slime control agent obtained in Example 1, and a bactericidal rate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Water storage tank 2 Supply pipe 3 Flowmeter 4 Mixer 5 Metering pump 6 Supply pipe 7 Hypohalite aqueous solution storage tank 8 Hose 9 Hose 10-1, 10-2, 10-3 Control valve 11-1, 11-2 11-3 Control valve 12 Metering pump 13 Storage tank 14 Mixing unit 15 Slime control agent supply hose 20 Slime control agent addition device 21 Main pipe 22 First liquid supply part 22A Metering pump 23 First liquid supply pipe 23A First liquid supply valve 24 Second liquid supply section 25 Second liquid supply pipe 25A Second liquid supply valve 26 Mixing section 27 Slime control agent addition pipe 28 White water main flow path 29 Addition control device 30 Paper machine 31 Wire part 32, 41 Drain pan 33 White water tank 34, 38 Circulating pump 35 Seed box 36 Press part 37 Deculator 38 Screen 4 0 Inlet 42 Couch pit

Claims (7)

  In the method of adding a slime control agent comprising a mixture of a hydantoin compound, ammonium halide, hypohalite and alkaline aqueous solution to the liquid to be treated, (A) diluting the first liquid comprising the hypohalite aqueous solution In addition, a second liquid composed of ammonium halide or a mixture of ammonium halide, hydantoin compound and aqueous alkali solution is mixed without being diluted and poured into the liquid to be treated. And (B) adding the first liquid and the second liquid, and then adding the mixture before the oxidation-reduction potential of the mixture becomes 850 mV or higher.   The method of adding a slime control agent according to claim 1, wherein the first liquid and the second liquid are mixed and then added to the liquid to be treated within 10 seconds.   The method for adding a slime control agent according to claim 1 or 2, wherein the hydantoin compound is 5,5-dimethylhydantoin.   The method for adding a slime control agent according to claim 1 or 2, wherein the ammonium halide is ammonium bromide or ammonium chloride.   The method for adding a slime control agent according to claim 1 or 2, wherein the hypohalite is an alkali metal hypohalite.   The method for adding a slime control agent according to claim 5, wherein the alkali metal hypohalite is sodium hypochlorite or sodium hypobromite.   A mixer connected to the water storage tank through a flow meter by a water storage tank and a supply pipe, a hypohalite aqueous solution storage tank connected by a supply pipe through the mixer and a metering pump, and a hose through a control valve From the above-mentioned mixer and hose through a control valve and a metering pump, from a slime control agent supply hose and a water storage tank having a mixing part connected to a storage tank of ammonium halide or a mixture of ammonium halide and a mixture of a hydantoin compound and an alkaline aqueous solution. Synchronize the amount of water, the amount of hypohalite aqueous solution from the hypohalite aqueous solution storage tank, the amount of ammonium halide or the mixture of these components from the storage tank of ammonium halide and hydantoin compound and alkaline aqueous solution To control Slime control agents continuously supply device characterized in that it consists because of the control means.

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