MXPA97009264A - Oxygen eliminator and cald water treatment chemical product - Google Patents

Abstract

The present invention relates to: An oxygen scavenger characterized in that the effective component thereof consists of a heterocyclic compound with an N-N bond in a ring thereof. An oxygen scavenger characterized in that the effective component thereof consists of a heterocyclic compound with an N-substituted amino group. An oxygen scavenger characterized in that the effective component thereof consists of a heterocyclic compound represented by the following formula: (wherein a, b are integers between 0 and 5 to satisfy the relation "2 < -a + b < - 5"). An oxygen scavenger characterized in that the effective component thereof consists of azodicarbonamide. An oxygen scavenger characterized in that it includes a heterocyclic compound with N-substituted amino group or salt thereof, and a hydroxybenzene derivative. They may also contain neutral amine, alkaline agent and / or soluble polymer in ag

Description

OXYGEN ELIMINATOR AND CHEMICAL WATER TREATMENT PRODUCT OF BOILER FIELD OF THE INVENTION AND RELATED TECHNIQUE The present invention relates to an oxygen scavenger, and more particularly to an oxygen scavenger that can effectively remove dissolved oxygen in water and in particular, is useful in the inhibition of corrosion. in a boiler system by removing the dissolved oxygen in the feedwater. In addition, the present invention relates to a boiler water treatment chemical that includes this oxygen scavenger and descaling chemicals. The oxygen dissolved in the feedwater # contributes to corrosion in the components of a boiler system; such as a main body of the boiler, a heat exchanger and an economizer arranged in a position upstream of the main body of the boiler, and a steam and condensate pipe arranged in a position downstream of the main body of the boiler. To inhibit corrosion in the boiler system, the dissolved oxygen in the feed water must be removed by a deoxidation treatment of the boiler feed water. Conventionally, chemical treatment or physical treatment has been applied to P15B7 / 97MX the removal of dissolved oxygen. As for the chemical treatment, a method has been widely employed to add an oxygen scavenger such as hydrazine (N H), sodium sulfite (Na 2 SO 3), hydroxylamine group, or saccharide in the boiler water. In JPB S59-42073 and JPA H6-23394 an agent containing a hydroxylamine group and a neutral amine is proposed. However, the safety of hydrazine for humans is problematic; and in this way the management of hydrazine is a risk. Since the reaction between sodium sulfite and oxygen is too rapid, sodium sulfite dissolved in water and stored in a tank reacts with oxygen in the air before it is added to the feedwater, reducing this the concentration of the effective component thereof. Therefore, there is a problem since sodium sulfite sometimes does not produce enough effect of removal of dissolved oxygen. Since the feed water treated with sodium sulphite contains sulfate ion as a reaction product of sodium sulfite and oxygen, there is another problem as corrosion and fouling in a boiler system is easily caused. There is also a problem since the hydroxylamine group generates acid such as nitric acid when the P1587 / 97MX The hydroxylamine group is added to the feed water and reacts with the oxygen in the boiler, thereby reducing the corrosion inhibiting effect for the main body of the boiler. The saccharide has disadvantages since it is difficult to handle the residual concentration in the boiler water and in this way it is difficult to control the correct amount that must be added, and the saccharide gives steam odor. The use of an azo compound as an oxygen scavenger has already been proposed. For example, 2,2-azobis (NjN'-dimethylene-isobutylamidine) 2,2-azobis (isobutylamide) -2-hydrate, 4,4-azobis (4-cyanocaproic acid), and 2,2-azobis have been proposed (2-amidinopropane) 'HCl. Each of these azo compounds provides high efficiency of dissolved oxygen removal. However, azo compounds have disadvantages of a production of various organic materials such as formic acid and acetic acid in the boiler and steam drum; thereby adversely affecting the quality of the steam and the purity of the vapor.

OBJECT AND SUMMARY OF THE INVENTION It is the first object of the present invention to provide a new oxygen scavenger that can efficiently remove dissolved oxygen in the water of P1587 / 97MX boiler feeding, while providing high safety for humans. It is the second object of the present invention to provide an oxygen scavenger having a heterocyclic compound with an N-substituted amino group as an effective component that can adequately exhibit the deoxidation effect not only for the feed water lines, for a main body of the boiler, or for steam and condensate lines for high temperature water, but also for the water supply lines for water at low temperature. It is the third object of the present invention to provide a new chemical for the treatment of boiler water that can exhibit corrosion inhibiting effect both to a boiler main body and to a pipe for steam and condensate. It is the fourth object of the present invention to provide a boiler water treatment chemical which has a high corrosion inhibition effect by a heterocyclic compound with an amino group N-substituted, and exhibiting excellent corrosion-inhibiting effect, and inhibition effect on embedding in a state of a solution containing component agents. An oxygen scavenger of a first aspect is characterized in that the effective component thereof P1587 / 97MX consists essentially of a heterocyclic compound having an N-N bond in a ring thereof. An oxygen scavenger in a second aspect is characterized in that the effective component thereof consists of a heterocyclic compound having an N-substituted amino group or its water soluble salt. An oxygen scavenger of a third aspect is characterized in that the effective component thereof consists of the following heterocyclic compound. (where a, b are integers between 0 and 5 to satisfy a relation "2 = a + b = 5"). An oxygen scavenger of a fourth aspect is characterized in that the effective component thereof consists essentially of a heterocyclic compound represented by the following formula: P1587 / 97MX (wherein Ri, R2, R3, R4 may be the same or different from each other and each designates any of hydrogen, lower alkyl group having 1 to 8 carbon atoms, and aryl group also having 1 to 8 carbon atoms. carbon, and X denotes any of hydrogen, amino group, alkyl group or dialkylamino group having from 1 to 8 carbon atoms, and lower alkyl group or aryl group having from 1 to 8 carbon atoms). An oxygen scavenger of a fifth aspect is characterized in that the effective component thereof consists essentially of azodicarbonamide. Oxygen scavengers from the first to the fifth aspect can be prepared by combining two or more kinds of components. The amount of the effective component of each aspect is not limited and can be altered to adequately correspond to the concentration of dissolved oxygen in the water as a material. Normally, the amount is, however, between 0.001 and 1000 mg, preferably between 1 and 300 mg, relative to one liter of the feed water. An oxygen scavenger of a sixth aspect is characterized by including a heterocyclic compound with an N-substituted amino group, or a salt thereof, and a hydroxybenzene derivative. In the oxygen eliminator of the sixth aspect, P1587 / 97MX due to the hydroxybenzene derivative catalyst, the heterocyclic compound with the N-substituted amino group or the salt thereof can exhibit the excellent deoxidation effect even in the feed water lines for water at low temperature. A seventh aspect provides a chemical for the treatment of boiler water characterized in that it includes a heterocyclic compound with an N-substituted amino group and neutral amine. An eighth aspect provides a chemical of the boiler water treatment characterized in that it includes a heterocyclic compound with an N-substituted amino group, or a salt thereof, and the alkalic agent and / or water-soluble polymer.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a graph showing the results of examples 36, 37 and the comparative examples of 6 to 8; and Figure 2 is a graph showing the results of the examples from 45 to 49 and a comparative example 21.

P1587 / 97MX PREFERRED MODALITIES 1. First Aspect An oxygen scavenger of a first aspect is characterized in that the effective component thereof consists of a heterocyclic compound having an N-N bond in a ring thereof. Included as this heterocyclic compound are at least one of the following: : 1,3-dimethyl-5-pyrazolone; HN-NH o- W -o: urazo1'- : 6-azauracil; : 3-methyl-5-pyrazolone; Y : 3-methyl-5-pyrazolin-5-one P1587 / 97MX The above heterocyclic compounds can be used alone or in combination.

Examples of 1 to JLO The effect of the oxygen scavenger of the first aspect was tested as follows: Softened water saturated with oxygen in air at room temperature was fed to a steam generator test autoclave and the autoclave was operated to generate low steam The following conditions: Temperature: 185SC, Pressure: 1 MPa, Evaporation Amount: 12 liter / hr, and Blowing Speed: 10%. The steam generated was completely condensed to produce water spray. Then, the concentration of dissolved oxygen in condensed water was measured by a dissolved oxygen meter. The value thus obtained was used as the data of a comparative example 1. On the other hand, steam was generated under the same conditions except that the oxygen scavenger was added to the feed water. Then, the concentration of dissolved oxygen in the condensed water of the vapor was also measured. The difference between the value obtained in this way and the data of comparative example 1 was calculated as an extraction amount and the ratio of the extraction to the data of the comparative example is P1587 / 97MX calculated as an extraction ratio (%). As for each Example from 1 to 10; the heterocyclic compound shown in Table 1 was dissolved in the above softened water to prepare an aqueous solution with a predetermined concentration, then the aqueous solution was fed into the feed water by a fixed displacement pump, and controlled as shown in Table 1 the concentration of the heterocyclic compound in the feed water. The results are shown in Table 1.

P15T7 / 97MX Ul ca TABLE 1 2. Second Aspect An oxygen scavenger of a second aspect is characterized in that the effective component thereof consists of a heterocyclic compound having an N-substituted amino group or water-soluble salt thereof. Included as a heterocyclic compound are preferably at least one of the following: : N-aminomorpholine CH) ~ N N NiÍ2: l-amino-4-methylpiperazine : N-aminohomopiperidine N-NH3: 1-aminopyrrolidine; Y : 1-aminopiperidine P15ß7 / 97MX Co or the salt thereof; for example, the water-soluble salt of the aforementioned heterocyclic compounds and the aliphatic carboxylic acid such as succinic acid, glutaric acid, adipic acid, gluconic acid, glycolic acid, lactic acid, malic acid, tartaric acid, or acid are preferably used. citric, or polycarboxylic acid such as polyacrylic acid, but the salt thereof is not limited thereto. The above heterocyclic compounds or salts thereof may be used alone or in combination.

Examples 11 to 21 The deoxidation treatment was done in each example in the same manner as in the above Examples 1 to 10; except that the heterocyclic compound shown in Table 2 was used as the effective component of the oxygen scavenger to obtain the concentration of the heterocyclic compound in the feedwater as shown in Table 2. The results are shown in Table 2.

P1587 / 97MX 3. Third Aspect An oxygen scavenger of a third aspect is characterized in that the effective component thereof consists of the following heterocyclic compound.

(OH) »CNH,), Included as this heterocyclic compound are at least preferably one of the following: : 2,3-diaminopyridine; Y 2-amino-hydroxypyrridine The above heterocyclic compounds can be used alone or in combination.

P1587 / 97MX Examples flß 22 to 27. The deoxidation treatment was done in each example in the same manner as in the above examples from 1 to 10, except that the heterocyclic compound shown in Table 3 was used as the effective component of the oxygen scavenger for have the concentration of the heterocyclic compound as shown in Table 3. The results are shown in Table 3.

P1587 / 97MX H 4. Fourth Aspect A eliminator of a fourth aspect is characterized in that the effective component thereof consists of a heterocyclic compound represented by the following formula: In this effective component of the oxygen scavenger of the fourth aspect, for example, methyl group is preferably used such as lower alkyl group having from 1 to 8 carbon atoms designated R 1, R 2, R 3, R 4 and phenyl group or tolyl group ee preferably used as the aryl group which also has from 1 to 8 carbon atoms, in addition, the methyl group or the aminomethyl group is preferably used as the alkyl group or the dialkylamino group having from 1 to 8 carbon atoms designated with X. Included as this heterocyclic compound are preferably at least one of the following: : 5-aminouracil; Y P1587 / 97MX (R 1, R 2 / R 3 / R 4 and X are all hydrogen) 5,7-diamino-1,3-dimethyluracil (R1, R2 are hydrogen, R3, R4 are methyl group, X is amino group). The above heterocyclic compounds can be used alone or in combination.

Examples 28 to 34 The deoxidation treatment was done in each example in the same manner as in the examples from 1 to 10 above, except that the heterocyclic compound shown in Table 4 was used as the effective component of the oxygen scavenger to have the concentration of the heterocyclic compound in the feed water as shown in Table 4. The results are shown in Table 4.

P1587 / 97MX TABLE 4 M O . Fifth Aspect An oxygen scavenger of a fifth aspect is characterized in that the effective component thereof is azodicarbon ida (NH2CON-NCONH2). The azodicarbonamide has the advantage of maintaining the purity of the generated steam without changing the quality of the water in the boiler because the azodicarbonamide does not produce any organic matter such as formic acid or acetic acid.

Example 35, Comparative Examples from 2 to 5 The deoxidation treatment was done in this example and each comparative example in the same manner as in the above Examples from 1 to 10, except that the azo compound shown in Table 5 was added as the effective component of the oxygen scavenger to have a concentration of 150 mg / L in the feedwater. The results are shown in Table 5. The main products in the generated steam and the main products in the autoclave are analyzed, respectively. The results are shown in Table 5.

P158 / 9 MX to As apparent from Table 5, all azo compounds provide high rates of removal of dissolved oxygen. In particular, azodicarbonamide does not generate organic acid that changes the quality of the feed water in the autoclave corresponding to a boiler drum so that azodicarbonamide is preferably used as the oxygen scavenger for the boiler feed water. 6 _? _ Sixth Aspect An oxygen scavenger of a sixth aspect is characterized by including a heterocyclic compound with an N-substituted amino group, or a salt thereof, and a hydroxybenzene derivative. In the oxygen scavenger of the sixth aspect, due to the hydroxybenzene derivative catalyst, the heterocyclic compound with the N-substituted amino group or the salt thereof can exhibit the excellent deoxidation effect even in the water feed lines for water to low temperature. The heterocyclic compound with the N-substituted e-group is preferably at least one of 1-aminopyrrolidine, l-amino-4-methylpiperazine, 1-aminopipe-ridine, l-aminohomopiperidine, 1,4-diaminopiperazine, N-aminomorpholine, and morpholinobiguanide . As the salt of P1587 / 97MX same; for example, the water-soluble salt of the heterocyclic compounds mentioned above and the carboxylic acid such as succinic acid, gluconic acid, glutaric acid, adipic acid, glycolic acid, lactic acid, malic acid, tartaric acid or citric acid are preferably used. or polycarboxylic acid such as polyacrylic, but the salt thereof is not limited thereto. These heterocyclic compounds and salts thereof may be suitably used alone or in combination. As the hydroxybenzene derivative, hydroquinone, 2,3-dimethyl 1,1-, 4-hydroquinone, catechol, 4-tert-butyl catechol, pyrogallol, 1,2,4-hydroxybenzene, gallic acid, 2-aminophenol, 2 can be used. , 4-diaminophenol, -aminophenol, but the hydroxybenzene derivative is not limited thereto. The hydroxybenzene derivative can also be suitably used alone or in combination. Although the oxygen scavenger of the sixth aspect can be prepared by mixing the heterocyclic compound with the N-substituted amino group or the salt thereof and the hydroxybenzene derivative, these can be injected separately. The amount of the oxygen scavenger of the sixth aspect can be altered to correspond adequately to the concentration of dissolved oxygen, and other P1587 / 97MX water conditions in the feed water of a boiler system as a matter. Usually, the heterocyclic compound with the N-substituted amino group or the salt thereof and the hydroxybenzene derivative are each added, however, between 0.001 and 1000 mg, preferably between 0.01 and 300 mg, more preferably between 0.02. and 100 mg in relation to 1 liter of feedwater. The effect ratio of the heterocyclic compound with the N-substituted amino group or the salt thereof and the hydroxybenzene derivative in the oxygen scavenger of the sixth aspect is, heterocyclic compound with N-substituted amino group or the salt thereof: derivative of hydroxybenzene = 1: 0.001-10 (weight ratio). When the hydroxybenzene derivative is smaller than the ratio, the effect is improved by using the hydroxybenzene derivative according to the present invention, ie, the improved effect of the deoxidation to the low temperature water can not be provided sufficiently. On the other hand, when the hydroxybenzene derivative is more than the ratio, the treatment cost becomes higher in relation to the increase in the effect. The oxygen scavenger of the sixth aspect dissolves in water in such a manner that the acescent hydroxybenzene derivative is neutralized by the compound P1587 / 97MX heterocyclic having the basic N-substituted amino group. When it is difficult to dissolve the oxygen scavenger, the addition of alkali such as caustic soda (NaOH) improves the solubility of the oxygen scavenger. Although the oxygen scavenger of the sixth aspect is characterized by including the heterocyclic compound with the N-substituted amino group or the salt thereof and the hydroxybenzene derivative if necessary; Another oxygen scavenger or corrosion inhibitor such as hydrazine, sodium sulfite, succinic acid or gluconic acid or additionally a dispersing agent, chelate compound, chemical scaling agents, or mixtures of some of these can also be added. The oxygen scavenger of the sixth aspect can be effectively used in boiler systems of various types such as low pressure, medium pressure and high pressure boiler systems not restricted to everything by boiler pressure, type of boiler boiler, or other kind of feed water.

Examples 36, 37; Comparative Examples from 6 to 8. After filling one liter of the softened water from the tap water of the city of Atsugi, in a flask Erlenmeyer; and control the pH to be at 9.0 when using NaOH, stirred for two hours in a temperature water bath P1387 / 97MX constant at 602C in such a way as to be saturated by oxygen in the air. The concentration of dissolved oxygen at this point was measured by a dissolved oxygen meter ("MOCA3600" manufactured by Obisfair Co., Ltd.) with the result being 4.75 mg / L). After adding the chemicals by the respective amounts shown in Table 6 in the water in the Erlenmeyer flask and stirring them sufficiently; the resulting solution was poured into three bottles of furan and 200 ml capacity and the furan bottles were capped without space in them and then returned to the constant temperature water bath at 60 seconds to provoke the reaction of the solution. The furan bottles were taken out of the constant temperature water bath, at a time with the passage of predetermined periods (5, 10, 20 minutes) and the dissolved oxygen concentrations in the solution were measured by the dissolved oxygen meter. The residual velocity of dissolved oxygen in each sample solution was calculated from the ratio of the dissolved oxygen concentration after adding the chemical compounds to that before adding the chemicals. These operations were quickly performed in a nitrogen atmosphere. The results are shown in Table 6 and Figure 1.

P1587 / 97MX As it is apparent from the results, it was found that the deoxidation reaction is significantly accelerated by using hydroquinone (HQ) as a hydroxybenzene derivative with 1-aminopyrrolidine (APY) or l-amino-4-methylpiperazine (AMPI) as a heterocyclic compound with the N-substituted amino group.

P1587 / 97MX Cu O TABLE 6 ro «o (Notes) Ex. : Example Ex. Co.: Comparative Example APY: 1-aminopyrrolidine AMPI: l-amino-4-methylpiperazine HQ: Hydroquinone 7. Seventh Aspect A seventh aspect provides a chemical for the treatment of boiler water which is characterized by including a heterocyclic compound with the N-substituted amino group and the neutral amine. The essential components of the chemical of this aspect are the heterocyclic compound with the N-substituted amino group and the neutral amine. The heterocyclic compound with the N-substituted amino group exhibits the excellent deoxidation effect, by reacting with dissolved oxygen in the boiler water to inhibit corrosion in a boiler main body. The chemical has the following useful functions in addition to the aforementioned functions of the heterocyclic compound with the N-substituted amino group. The heterocyclic compound with the N-substituted amino group has volatility characteristics and excellent reduction capacity in relation to iron. In other words, the heterocyclic compound has functions of inhibiting the oxidation of iron, that is, it inhibits the corrosion of iron. Therefore, the steam condensate, generated from the boiler water treated with the chemical P1587 / 97MX of the sixth aspect, the characteristics of the corrosion of a pipe through which the steam condensate passes due to the aforementioned functions of the heterocyclic compound that is included in the steam condensate is stripped. In addition, the steam condensate is maintained at a pH range of neutral or alkaline due to the functions of the neutral amine that are also included in the condensate, and thereby inhibiting the corrosion of the pipe through which the condensed. That is, the chemicals of this aspect can exhibit the effect of corrosion inhibition in the main body of the boiler as well as the steam and condensate pipe. Any compound that can exhibit the functions and effects as mentioned above can be employed as the heterocyclic compound with the N-substituted amino group. For example, N-aminomorpholine, 1-aminopyrrolidine, 1-amino-4-methylpiperazine, 1,4-diaminopiperazine, 1-aminopiperidine, 1-aminohomopiperidine, morpholinobiguanide, and the water-soluble salt of the aforementioned heterocyclic compounds can be preferably used. above and also preferably the carboxylic acid such as succinic acid, gluconic acid, glutaric acid, adipic acid, glycolic acid, lactic acid, malic acid, acid may be used.

P1587 / 97MX tartaric, or citric acid, polycarboxylic acid such as polyacrylic acid. In addition, these heterocyclic compounds and the salts thereof may be suitably used alone or in combination. Any compound that is capable of making the water in the boiler after the treatment and the steam condensate, neutral or alkaline, can be used as the neutral amine, the other essential component of the chemical. For example, cyclohexylamine, 2-amino-2-methyl-1-propanol, monoethane-lamel, diethanolamine, morpholine, monoisopropanolamine, diethylethanolamine, dimethylpropanolamine, dimethylethane-lamel, and dimethylpropylamine can be preferably used. These can be used properly alone or in combination. The chemical of the seventh aspect is prepared by mixing the heterocyclic compounds and the neutral amine as mentioned above. The mixing ratio thereof can be determined to adequately correspond to the concentration of the dissolved oxygen and the other water conditions in the feed water of the boiler system as a material. However, the heterocyclic compounds and the neutral amine are each usually added between 0.001 and 1000 mg, preferably between 0.01 and 300 mg; more preferably between 0.02 and P1587 / 97MX 100 mg; in relation to 1 liter of feed water. Although the essential components of the chemical of the seventh aspect are the heterocyclic compound with the N-substituted amino group and the neutral amine; it is also possible to add another known oxygen scavenger or corrosion inhibitor such as hydrazine, sodium sulphite, succinic acid or gluconic acid, or additionally the known dispersing agent, chelate compound, scaling chemicals, or mixture of any of these . The chemical of the seventh aspect can be effectively used in boiler systems of various types such as low pressure, medium pressure, and high pressure boiler systems, and is not restricted to everything by the pressure of the boiler or the boiler. type of feed water.

Examples from 38 to 44, Comparative Examples from 9 to 20 After the softened water is fed from the tap water of the town of Atsugi which has been saturated by oxygen from the air at 402C in an experimental electric boiler with a capacity of 5 liters and the boiler was operated to generate steam under the following conditions: Temperature: 1832C, Pressure: 1 MPa, Evaporation Amount: 12 liters / hr, and Blowing Speed: 10%. The steam was used to produce condensate. He P1S87 / 97MX The condensate was cooled to 50 ° C and then fed into a column. Previously placed in the column and the experimental electric boiler mentioned above were test coupons made of steel (SS400 of Japanese Industrial Standard) having a length of 50 mm, a width of 15 mm, and a thickness of 1 mm. The test coupons were immersed in the condensate 96 hours. The corrosion amounts of the respective coupons were measured to calculate the corrosion rates in the boiler water and the condensate. The resulting values were indexes that represent the corrosion degree of the coupons caused by the boiler water without the chemical treatment. The results are shown in Table 8 as a Comparative Example 9. It should be noted that the concentration of the nitrate ion and the concentration of the nitrite ion in the boiler water after evaporation were measured and the results are also shown in Table 8 The chemical components shown in Table 7 were dissolved in the softened water mentioned above and in such a way as to have the respective concentrations indicated in the softened water and then supplied to the boiler by using a fixed displacement pump.

P1587 / 97MX ? As for the steam condensate generated from the softened water in which the chemical components are dissolved, the corrosion test was made under the conditions as those of the comparative example 9 mentioned above for calculating the corrosion rate of the test coupons. In addition, the concentration of the nitrate ion and the concentration of the nitrite ion in the boiler water after the operation were measured. The results are shown in table 8.

P1587 / 97MX or ? TABLE 8 As it is apparent from Table 7 and Table 8, the following facts are found: 1) Chemicals that include hydroxyamine groups (comparative examples of 10 to 17) are not suitable for the inhibition of boiler corrosion that the nitrate ion and the nitrite ion are produced in the boiler water. 2) The use of the heterocyclic compound with the N-substituted amino group only reduces the corrosion rate of the iron in the boiler water and does not produce the nitrate ion and the nitrite ion in the boiler water. However, since the corrosion rate of the iron in the condensate is even greater so that corrosion will occur in the steam and condensate pipe, the heterocyclic compound is not convenient. 3) Compared to the above comparative examples, the use of any of the chemicals in the examples does not produce the nitrate ion and the nitrite ion in the boiler water and significantly inhibits the corrosion of iron in both the boiler water and the water. the condensate. 8. Eighth Aspect A boiler water treatment chemical of the eighth aspect is characterized by including a P1587 / 97MX heterocyclic compound with the N-substituted amino group, or the salt of the mieme, and the alkalic agent and / or water-soluble polymer. The heterocyclic compound with the N-substituted amino group or the salt thereof has the characteristic of a slower deoxidation reaction under the neutral condition and the higher deoxidation reaction under the alkaline condition in the case of low temperature water. Accordingly, the use of the alkaline agent improves the deoxidation effect of the heterocyclic compound even in the pipeline for the low temperature water. As a result of this, the deoxidation effect in the feed water lines is further improved and the amount of iron introduced into the boiler is reduced. The iron enters from the feed water and the diluted iron from the drum of the boiler adheres as iron oxide sludge to a heating surface. The iron oxide mud causes a concentration cell of oxygen or the like to contribute to corrosion. The increase in the effect of corrosion inhibition in the feed water line can reduce this secondary corrosion. The use of the water soluble polymer reduces the corrosion, caused by the iron oxide mud, by its sludge dispersion function, and additionally, can P1S87 / 97MX Prevent the incrustation on the heating surface even when the hardness components escape from a softener or an ion exchange device. Because the pH of the steam condensate is maintained to be neutral or alkaline by the use of the neutral amine, the corrosion of the pipe to the steam condensate (ie, the steam drain line) is inhibited. As the heterocyclic compound with the N-substituted amino group used in the eighth aspect, preferably 1-aminopyrrolidine, l-amino-4-methylpiperazine, 1-aminopiperidine, 1-aminohomopiperidine, 1,4-diaminopiperazine, N-aminomorpholine may be employed. , and orfolinobiguanide. As the salt thereof, for example, the water-soluble salt of the mentioned heterocyclic compounds nucleic acid, and aliphatic carboxylic acid such as succinic acid, glutaric acid, adipic acid, gluconic acid, glycolic acid, lactic acid, acid is preferably employed malic, tartaric acid, or citric acid or polycarboxylic acid such as polyacrylic acid, but the salt thereof is not limited thereto. These heterocyclic compounds and salts thereof may be suitably used alone or in combination. As the alkaline agent used in the eighth aspect, sodium hydroxide, hydroxide of P1587 / 97MX potassium, but the alkaline agent is not limited to this. The alkaline agents can be used suitably alone or in combination. As the water-soluble polymer used in the eighth aspect, polyacrylic acid, polymaleic acid, polymethacrylic acid, copolymer of acrylic acid and acrylic amide, copolymer of acrylic acid and hydroxyalyloxypropanesulfonic acid, copolymer of acrylic acid and 2-acrylamide are used. 2-methylpropanesulfonic, and the salt thereof, but is not limited to this. These water-soluble polymers ee may suitably be used alone or in combination. As the neutral amine used in the eighth aspect, any compound capable of making the water of the boiler and the steam condensate neutral or alkaline can be employed. For example, cyclohexylamine, 2-amino-2-methyl-1-propanol, monoethane-lamel, diethanolamine, morpholine, monoisopropanolamine, di-ethylethanolamine, diethylethanolamine, dimethylpropane-lamel, and dimethylpropylamine are preferably used. Suitably, these may be used alone or in combination. Although the boiler water treatment chemical of the eighth aspect can be prepared by mixing the aforementioned heterocyclic compound with the N-substituted amino group or the salt thereof and the agent P1587 / 97MX alkaline and / or water-soluble polymer, and additionally by mixing the neutral amine if necessary, these can be injected separately. The quantity of the boiler water treatment chemical the sixth aspect can be altered to correspond adequately to the dissolved oxygen concentration; and other water conditions in the feed water of the boiler system as a matter. However, the heterocyclic compound with the N-substituted amino group or the salt thereof and the alkalic agent and / or the water-soluble polymer are each usually added between 0.001 and 1000 mg, preferably between 0.01 and 300 mg , more preferably between 0.02 and 100 mg in relation to 1 liter of feed water. In particular, the alkaline agent is preferably added in such a way that the pH becomes between 8 and 12, depending on the type of boiler. When the neutral amine is used with the boiler water treatment chemical, the preferred amount of neutral amine is between 0.01 and 500 mg, particularly between 0.1 and 100 mg relative to 1 liter of feedwater. In the boiler water treatment chemical of the eighth aspect, the ratio of the heterocyclic compound to the N-substituted amino group or the salt of the P1387 / 97HX same and the alkaline agent and / or water soluble polymer is preferably established as follows (the ratio is by weight). (1) When the heterocyclic compound is used together with the N-substituted amino group or the salt thereof and the alkalic agent, Heterocyclic compound with N-substituted amino group or the salt thereof: Alkalic agent = 1: 0.01-20. (2) When the heterocyclic compound is used together with the N-substituted amino group or the salt thereof and the water soluble polymer, N-substituted heterocyclic compound or the salt thereof: Water soluble polymer - 1: 0.01-20. (3) When the heterocyclic compound is used together with the N-substituted amino group or the salt of the amine and the alkalic agent and the water-soluble polymer, heterocyclic compound with N-e-substituted amino group or the salt thereof: Alkalic agent: Water soluble polymer = 1: 0.01-20: 0.01-20. Additionally, when the neutral amine is used with this, the preferable ratio is, heterocyclic compound with N-substituted amino group or the salt thereof: neutral amine = 1: 0.01-20 (weight ratio). Although the essential components of the product P1S87 / 97MX boiler water treatment chemical of the eighth aspect are the heterocyclic compound with the N-substituted amino group or the salt thereof and the alkalic agent and / or water soluble polymer and the neutral amine if necessary; it is also possible to add another known oxygen scavenger or corrosion inhibitor such as hydrazine, sodium sulfite, saccharide, succinic acid, gluconic acid or amines other than the neutral amine mentioned above, or additionally the known dispersing agent, chelate compound, products descaling chemicals, or the mixture of any of these. The boiler water treatment chemical of the eighth aspect can be effectively used in boiler systems of various types, such as low pressure, medium pressure and high pressure boiler systems; and it is not reefed in everything by the pressure of the boiler, the type of boiler, or the type of feed water. Later in the present, the eighth aspect will be described in more detail with some examples and comparative examples.

Examples 45 to 49, Comparative Example 21 Five kinds of test liquids were prepared P1SB7 / 97MX by adding sodium hydroxide as the alkalic agent in one liter of deionized water in such a way that the respective pH becomes 8.0, 9.0, 10.0, 11.0, and 12.0. These are stirred for a few hours in a water bath of constant temperature at 60 ° C and saturated by oxygen in air. The respective dissolved oxygen concentrations were measured by a dissolved oxygen meter ("MOCA3600" manufactured by Obisfair). After adding 100 mg of 1-inopyrrolidine (1-AP) as the heterocyclic compound with the N-substituted amino group; and shake them sufficiently, the resulting solutions were poured into furan bottles of 200 ml capacity and the furan bottles were covered ein space in them and then returned to the constant temperature water bath at 60 ° C to provoke the reaction of the eolution. After 20 minutes, the furan bottles were removed from the temperature bath of temperature, and the dissolved oxygen concentrations in the solution were measured by the dissolved oxygen meter. The residual proportion of the oxygen dissolved in each test liquid was calculated from the ratio of the concentration of the dissolved oxygen after adding the 1-aminopyrrolidine to that before adding the agent (Examples 45 to 49). These operations were carried out quickly under a nitrogen atmosphere.

P1587 / 97MX For comparison, the test was made for a test liquid with a pH of 6.8 without adding sodium hydroxide in the same manner (Comparative Example 21). The results of this test are shown in Table 9 and Figure 2. As it is apparent from the results, it is found that the use of 1-aminopyrrolidine as the heterocyclic compound with the N-substituted amino group and the alkalic agent improves significantly the effect of deoxidation.

P1387 / 97MX TABLE 9 Examples from 50 to 55, Comparative Examples 22, 23 After adding 30 mg of 1-aminopyrrolidine as the heterocyclic compound with the N-substituted amino group in water softened from tap water of the city of Ateugi which has eaten by oxygen in at 40BC; the re-emerging water was fed into an experimental electric boiler with a capacity of 5 liters and the boiler was operated to generate steam under the following conditions. The operating time was 240 hours. Conditions: Temperature: 183se, P1587 / 97MX Pressure: 1 MPa, Evaporation amount: 11 liters / hr Blowing speed: 10%, and Iron concentration in the feed water: 0.5 mg / L. Previously placed on the feedwater line, the drum of the electric boiler, and the steam drain line were processed steel test coupons (SS400 of the Japanese Industrial Standard) each having a length of 50mm, a width of 15 mm and a thickness of 1 mm. The degree of corrosion of the test coupons was measured to calculate the corrosion ratios. The results are shown in Table 10. The amount of iron contained in the accumulation of iron dioxide (the amount of iron deposited) in the coupon placed in the drum of the boilers was measured and the result is shown in Table 10 ( Comparative Example 22). The chemical components shown in Table 10 ee die in softened water mentioned above in such a way to have the respective concentrations indicated in the softened water shown in Table 10 and then fed into the boiler when using the fixed displacement pump. As for the steam condensate generated from the softened water in which the P1587 / 97MX Chemical components; the corrosion test was made under the same conditions as mentioned above to calculate the corrosion rate of the test coupons and the amount of iron deposited and the results are shown in Table 10 (Examples 50 to 55, Comparative Example 23 ). As apparent from Table 10, it was found that the enhanced corrosion inhibiting effect and the descaling effect can be obtained by removing the 1-aminopyrrolidine and the alkalic agent and / or the water soluble polymer, and by additionally using the neutral amine.

P1587 / 97MX TABLE 10 or * 1-AP: 1-aminopyrrolidine Water-soluble polymer: copolymer of acrylic acid and hydroxyalyloxypropanesulfadic acid AMP: 2-amino-2-methyl-l-propanol As apparent from the foregoing description, any of the oxygen scavengers of the first to fifth aspects of the present invention can efficiently remove dissolved oxygen in water. When used as an oxygen scavenger for the feedwater for a boiler, any of these can inhibit corrosion in a boiler main body and a steam and condensate pipe caused by dissolved oxygen. Therefore, each oxygen scavenger has high industrial utility. Additionally, the fifth aspect provides an oxygen scavenger which prevents the development of its products in the boiler so as not to affect the purity of the vapor. The sixth aspect provides an oxygen scavenger which has improved deoxidation effect in the feed water lines for the water at low temperature and which is markedly superior in inhibiting corrosion in a feed water pipe compared to a conventional one. The chemical for treating the boiler water of the sixth aspect exhibits excellent corrosion inhibiting effect in relation to any of a boiler main body and steam and condensate lines although the chemical is a one component agent.

P1587 / 97MX This is because the heterocyclic compounds with the N-substituted amino group and the neutral amine are contained in the chemical. The eighth aspect provides a boiler water treatment chemical that has both the excellent corrosion inhibiting effect and the desiccation effect although the chemical is the one component agent.

P1587 / 97MX

Claims (37)

1. NOVELTY OF THE INVENTION Having described the present invention, it is considered as a novelty and, therefore, claimed as property is contained in the following CLAIMSt 1. An oxygen scavenger characterized in that the effective component thereof consists of a heterocyclic compound with a NN union in a ring of the same.
2. 2. An oxygen scavenger according to claim 1, wherein the compound is l, 3-dimethyl-5-pyrazolone. : l, 3-dimethyl-5-pyrazolone
3. 3. An oxygen scavenger according to claim 1, wherein the compound is urazole.
4. 4. An oxygen scavenger according to claim 1, wherein the compound is 6-azauracil P1587 / 97MX : 6-azauracil
5. 5. An oxygen scavenger according to claim 1, wherein the compound is 3-methyl-5-pyrazolone. : 3-methyl-5-pyrazolone;
6. 6. An oxygen scavenger according to claim 1, wherein the compound is 3-methyl-5-pyrazolin-5-one : 3-methyl-5-pyrazolin-5-one
7. 7. An oxygen scavenger characterized in that the effective component thereof consists of a heterocyclic compound with an N-substituted or e-soluble amino group in the water of the membrane. P1587 / 97MX
8. 8. An oxygen scavenger according to claim 7, wherein the compound is N-aminomorpholine. 0 N-NHt 'N-aminomorpholine \ /
9. 9. An oxygen scavenger according to claim 7, wherein the compound is l-amino-4-methylpiperazine. peraz? na
10. 10. An oxygen scavenger according to claim 7, wherein the compound is N-aminohomopiperidine. : N-aminohomopiperidma
11. 11. An oxygen scavenger according to claim 7, wherein the compound is 1-aminopyrrolidine. P1587 / 97MX na Y
12. 12. An oxygen scavenger according to claim 7, wherein the compound is 1-aminopiperidine. : 1-aminopiperidine
13. 13. An oxygen scavenger according to any of claims 8 to 12, wherein the water-soluble salt of the heterocyclic compound is a salt of the heterocyclic compound and aliphatic carboxylic acid such as succinic acid, gluconic acid, glutaric acid, adipic acid, glycolic acid, lactic acid, malic acid, tartaric acid or citric acid or polycarboxylic acid such as polyacrylic acid. 14. An oxygen scavenger characterized in that the effective component thereof connects a heterocyclic compound repreeded by the following formula
14. P1587 / 97MX (where a, b are integers between 0 and 5 to satisfy the relation "2 < a + b < 5").
15. 15. An oxygen scavenger according to claim 14, wherein the compound is 2,3-diaminopyridine. : 2,3-diaminopyridine; Y
16. 16. An oxygen scavenger according to claim 14, wherein the compound is 2-amino-3-hydroxypyridine. : 2-amino-hydroxypyrridine
17. 17. An oxygen scavenger characterized in that the effective component thereof consists of a heterocyclic compound repreeded by the following formula:
18. P1587 / 97MX (wherein R1 t R2 / R3, R4 are the same or different from each other and each designates any of hydrogen, lower alkyl group having 1 to 8 carbon atoms, and aryl group also having 1 to 8 carbon atoms and X denotes any of hydrogen, amimo group, alkyl group or dialkylamino group having from 1 to 8 carbon atoms and lower alkyl group or aryl group having from 1 to 8 carbon atoms). 18. An oxygen scavenger according to claim 17, wherein the lower alkyl group having from 1 to 8 carbon atoms designated by Rj_, R2, R3, R4 is methyl group, the aryl group having from 1 to 8 carbon atoms. carbon designated by Rl R2, R3, R4 the phenyl group or tolyl group, and wherein the alkyl group or dialkylamino group having from 1 to 8 carbon atoms designated by X is methyl group or amino ethyl group.
19. 19. An oxygen scavenger according to claim 18, wherein the compound is 5-aminouracil. : 5-aminouracil; Y
20. 20. An oxygen scavenger according to claim 18, wherein the compound is 5,6-diamino- P1587 / 97MX 1,3-dimethyluracil : 5, 7-diamino-l, 3-dimethyluracil
21. 21. An oxygen scavenger characterized in that the effective component thereof consists of azodicarbonamide.
22. 22. An oxygen scavenger characterized in that it includes a heterocyclic compound with an N-substituted amino group, or the salt thereof, and a hydroxybenzene derivative.
23. 23. An oxygen scavenger according to claim 22, wherein the heterocyclic compound with N-substituted amino group is 1-aminopyrrolidine, l-amino-4-methylpiperazine, 1-aminopiperidine, 1-aminohomopiperidine, 1,4-diaminopiperazine, N -aminomorholina, or morholinobiguanida.
24. 24. An oxygen scavenger according to claim 23, wherein the salt of the heterocyclic compound is water-soluble salt of the heterocyclic compounds and carboxylic acid such as succinic acid, gluconic acid, glutaric acid, adipic acid, glycolic acid, lactic acid, malic acid, acid P1587 / 97MX tartaric, or citric acid, or polycarboxylic acid such as polyacrylic acid.
25. 25. An oxygen scavenger according to claim 22, wherein the hydroxybenzene derivative is one or more of hydroquinone, 2,3-dimethyl-1,4-hydroquinone, catechol, 4-tert-butyl catechol, pyrogallol, 1, 2,4-hydroxybenzene, gallic acid, 2-aminophenol, 2,4-diaminophenol, and 4-aminophenol.
26. 26. An oxygen scavenger according to claim 25, wherein the hydroxybenzene derivative is hydroquinone.
27. 27. An oxygen scavenger according to claim 22, wherein the ratio of the heterocyclic compound to the N-substituted amino or the eal amino group and the hydroxybenzene derivative is heterocyclic compound with N-substituted amino group or the salt thereof: hydroxybenzene derivative = 1: 0.001-10 (weight ratio).
28. 28. A chemical for treating boiler water, characterized by including a heterocyclic compound with N-substituted amine group and neutral amine.
29. 29. A chemical product according to claim 28, wherein the heterocyclic compound is N-aminomorpholine, 1-aminopyrrolidine, l-amino-4-methylpiperazine, 1,4-diaminopiperazine, 1-aminopiperidine, P1587 / 97MX 1-aminohomopiperidine, morpholinobiguamide, or water-soluble salt of the aforementioned heterocyclic compounds and carboxylic acid such as succinic acid, gluconic acid, glutaric acid, adipic acid, glycolic acid, lactic acid, malic acid, tartaric acid, or citric acid, polycarboxylic acid such as polyacrylic acid.
30. 30. A chemical according to claim 28, wherein the neutral amine is cyclohexylamine, 2-amino-2-methyl-l-propanol, onoetalamine, diethanolamine, morpholine, monoisopropanolamine, di-ethylethanolamine, diethylethanolamine, dimethylpropanolamine, or dimethylpropylamine.
31. 31. A boiler water treatment chemical characterized in that it includes a heterocyclic compound with N-substituted amino group, or salt thereof, and alkalic agent and / or water soluble polymer.
32. 32. A boiler water treatment chemical according to claim 31, which further includes neutral amine.
33. 33. A boiler water treatment chemical according to claim 31, wherein the heterocyclic compound with N-substituted amino group is 1-aminopyrrolidine, l-amino-4-methylpiperazine, 1-aminopi-peridine, 1-aminohomopiperidine, 1,4-diaminopiperazine, P1587 / 97MX N-aminomorpholine, or morpholinobiguanide, and wherein the salt thereof is water soluble salt and the heterocyclic compounds and aliphatic carboxylic acid such as succinic acid, glutaric acid, adipic acid, gluconic acid, glycolic acid, lactic acid, malic acid, tartaric acid, or citric acid, or polycarboxylic acid such as polyacrylic acid.
34. 34. A boiler water treatment chemical according to claim 31, wherein the alkalic agent is sodium hydroxide, potassium hydroxide, sodium carbonate and potassium carbonate.
35. 35. A boiler water treatment chemical according to claim 31, wherein the water-soluble polymer is polyacrylic acid, polymaleic acid, polymethacrylic acid, copolymer of acrylic acid and acrylic amide, copolymer of acrylic acid and hydroxyalyloxypropanesulfonic acid, copolymer of acrylic acid and 2-acrylamide-2-methylpropanesulfonic acid, or eal of it.
36. 36. A boiler water treatment chemical according to claim 31, wherein the neutral amine is one or more of cyclohexylamine, 2-amino-2-methyl-1-propanol, monoethanolamine, diethanolamine, morpholine, mono-ieopropanolamine, dimethylethanolamine, diethylethanolamine, dimethylpropanolamine, and di-ethylpropylamine. P1587 / 97KX
37. 37. A boiler water treatment chemical according to claim 31, wherein the ratio of the heterocyclic compound with N-substituted amino group or the salt thereof and the alkalic agent and / or the water soluble polymer is exposed as follows by weight i) when the heterocyclic compound with N-substituted amino group or the salt thereof and the alkalic agent are used together. heterocyclic compound with N-substituted amino group or the salt thereof: alkalic agent = 1: 0.01-20; ii) when the heterocyclic compound with N-substituted amino group or the salt thereof and the water soluble polymer are used together, heterocyclic compound with N-substituted amino group or the salt thereof: water soluble polymer = 1: 0.01- 20, and iii) when the heterocyclic compound with the N-substituted amino group or the salt thereof and the alkalic agent and the water-soluble polymer, heterocyclic compound with N-e-substituted amino group or the eal thereof: Alkalic: water soluble polymer = 1: 001-20: 0.01-20. P1587 / 97MX SUMMARY OF THE INVENTION An oxygen scavenger characterized in that the effective component thereof consists of a heterocyclic compound with an N-N bond in a ring thereof. An oxygen scavenger characterized in that the effective component thereof consists of a heterocyclic compound with an N-substituted amino group. An oxygen scavenger characterized in that the effective component thereof consists of a heterocyclic compound represented by the following formula: (where a, b eon whole number between 0 and 5 to eat the relationship "2 = a + b = 5"). An oxygen scavenger characterized in that the effective component of the azenecarbonamide coneiete. An oxygen scavenger characterized in that it includes a P1387 / 97MX heterocyclic compound with N-suetituted amino group or the eal thereof, and a hydroxybenzene derivative. They may also contain neutral amine, alkaline agent and / or water soluble polymer. P1587 / 97MX