JP2001009499A - Scale inhibitor, method for preventing scale buildup and deodorizing apparatus protected from scale buildup - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the deposition of scale forming materials on a packing material by adding a specified compound to water to be sprinkled. SOLUTION: In a deodorizing tower using a circulation type water sprinkling system or a temporary water sprinkling system and sodium hypochlorite as a cleaning fluid, a compound of the formula is added to water to be sprinkled preferably in 5-500 mg/l. At least one selected from polyacrylic acid, its copolymer, polymaleic acid and its copolymer is preferably added in 1-300 mg/l besides the compound of the formula. Bis(poly-2-carboxyethyl)phosphinic acid may be used as the compound of the formula. The deposition of scale forming materials (sulfur, sulfur compounds and calcium compounds) on a packing material is prevented, the increase of pressure drop in a packed bed is prevented and stable deodorizing operation is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a scale inhibitor,
The present invention relates to a method for preventing scale adhesion and a deodorizing apparatus in which scale adhesion is prevented. It relates to a deodorizing device which is prevented.

[0002]

2. Description of the Related Art As a deodorizing tower, for example, there is a circulating watering type as shown in FIG. This deodorization tower has a packed bed 4 for improving deodorization efficiency and a water sprinkler 5 for spraying water toward the packed bed 4 in an upper part of a deodorization tower 3 having an odor gas inlet 1 and a deodorant gas outlet 2. And a circulating pump 7 for supplying circulating water in the water storage unit 6 to the sprinkler 5 outside the deodorization tower 3.

[0003] In such a deodorizing tower, when an odor gas containing a sulfur-based odor component such as hydrogen sulfide generated in a human waste treatment plant is to be deodorized, the odor gas is introduced into the tower to fill the packed bed 4. The sulfur-based odor component contained in the odorous gas is decomposed by passing the odorous gas through the water and contacting the circulating water containing sodium hypochlorite sprayed by the water spray device 5.

When water is sprayed, as shown in FIG. 3, an alkaline agent such as sodium hydroxide is added to the circulating water in the water storage section 6 to maintain the circulating water to be sprayed alkaline and to store the water. Supply water is supplied to the section 6 to keep the salt concentration lower than a predetermined value, thereby preventing sulfur and sulfur compounds generated by the decomposition of odor components from adhering to scale. Further, in order to prevent the adhesion of calcium scale, polyacrylic acid or polymaleic acid may be added to the circulating water. (Not shown) In such a deodorization tower, when a large amount of scale adheres, the pressure loss increases, and eventually the operation becomes impossible.

[0005]

However, in such equipment, since the pH of the circulating water is high, even if polyacrylic acid or polymaleic acid which is generally used as a scale inhibitor is added, a sufficient effect cannot be obtained. Regular cleaning work was required. Furthermore, these conventional scale inhibitors may be oxidatively decomposed by hypochlorous acid or adsorbed by sulfur or the like, so that a high amount of addition is required even when a short-term effect is obtained.

[0006] The present invention solves the above-mentioned problems, and in a dewatering tower of a circulation type or a once-through type,
A scale inhibitor, a method for preventing scale adhesion, and a method for preventing scale adhesion, which are problematic when sodium hypochlorite is used, which prevent scale-causing substances (eg, sulfur, sulfur compounds and calcium compounds) from adhering to the filler. It is an object of the present invention to provide a deodorizing device.

[0007]

The above problems have been solved by the following scale inhibitor, a method for preventing scale adhesion, and a deodorizing apparatus in which scale adhesion is prevented. That is, the present invention provides: 1. A scale inhibitor comprising a compound represented by the following chemical formula (1):

[0008]

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[0009] 2. 2. The scale inhibitor according to the above item 1, which further comprises at least one of polyacrylic acid and a copolymer thereof, and polymaleic acid and a copolymer thereof. In the deodorization tower of the circulation type water spray method or the one-time water spray method using sodium hypochlorite as the washing liquid,
A method for preventing scale adhesion, comprising adding a compound represented by the following chemical formula (1) to water spray to prevent adhesion of a scale-causing substance to a filler.

[0010]

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4. 4. The method for preventing scale adhesion according to the above item 3, wherein the amount of the compound represented by the chemical formula (1) added to the water spray is 5 to 500 mg / liter. 5. The method for preventing scale adhesion according to the above item 3 or 4, wherein at least one of polyacrylic acid and its copolymer, and polymaleic acid and its copolymer is added together. Inside a deodorizing device having an odor gas inlet and a deodorizing gas outlet, a packed bed for deodorizing odor gas,
In a deodorizing device provided with a water spray device for spraying water on the upper portion of the packed bed and a water storage portion on a lower portion of the packed bed, passing of a cleaning liquid containing a compound represented by the following chemical formula (1) to the water spray device. A deodorizing apparatus characterized by having means for preventing scale adhesion. "

[0012]

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[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below, but the present invention is not limited thereto. The present invention is a dewatering tower of a circulation type water spray method or a one-time water spray method,
The present invention relates to a method of preventing scale-causing substances (for example, sulfur, sulfur compounds, and calcium compounds) from adhering to a filler, which is a problem when sodium hypochlorite is used.

In the method for preventing scale adhesion according to the present invention, the compound represented by the chemical formula (1) is added to water by spraying 5 to 50 times.
It is preferable to add so as to be 0 mg / liter. Thereby, it is possible to effectively prevent the sulfur, the sulfur compound and the calcium compound from adhering to the filler. Further, along with the addition of the compound represented by the chemical formula (1), at least one of polyacrylic acid and a copolymer thereof, polymaleic acid and a copolymer thereof is 1 to 300.
It is preferable to add them together in mg / liter watering.

Specific examples of the compound represented by the chemical formula (1) include bis (poly-2-carboxyethyl) phosphinic acid. When the amount of the compound added is 5
When the amount is less than mg / liter, the effect of preventing the adhesion of scale becomes insufficient, and when it exceeds 500 mg / liter, the decomposition product of the compound itself causes the scale, which is not preferable. The most preferred loading is in the range of 10-200 mg / liter. Along with the compound represented by the chemical formula (1), at least one of polyacrylic acid and its copolymer, and polymaleic acid and its copolymer is 1 to 300 mg /
It is preferable to add together the liter, because the effect of preventing scale adhesion can be significantly increased. However, if the amount is less than 1 mg / l, a sufficient combined effect cannot be obtained, and if it exceeds 300 mg / l, gelation occurs, which is not preferable. Most preferred loadings are in the range of 5-150 mg / l.

[0016]

Examples of the present invention will be described below. Example 1 In a circulation type watering type deodorization tower shown in FIG. 1, an odor gas containing a sulfur-based odor component such as hydrogen sulfide at a high concentration was introduced into the tower, passed through a packed bed, and sprayed by a watering device. Bis (poly-2-carboxyethyl) phosphinic acid is added to circulating water of a deodorization tower, which decomposes odor components by contact with water containing sodium hypochlorite, and changes over time of the deposits on the filler. Was observed. Table 1 shows the results.
As shown in FIG.

[0017]

[Table 1]

As shown in Table 1, by adding the compound represented by the chemical formula (1) to water spray in an amount of 5 to 500 mg / liter, scale adhesion can be effectively prevented.

Example 2 Bis (poly-2-carboxyethyl) phosphinic acid and polyacrylic acid were added to circulating water in a deodorization tower under the same conditions, and changes over time in the deposits on the filler were observed. (See FIG. 2) The results are as shown in Table-2.

[0020]

[Table 2]

As shown in Table 2, together with the addition of the compound represented by the chemical formula (1), polyacrylic acid and its copolymer or polymaleic acid and its copolymer were added to 1 to 300 mg / liter of water spray. The addition can significantly prevent scale adhesion.

[0022]

As described above, the compound represented by the above chemical formula (1) is added to water spray in a circulating water spray system or a transient water spray system deodorization tower using sodium hypochlorite as a washing liquid. By preventing scale-causing substances (sulfur, sulfur compounds and calcium compounds) from adhering to the filler, preventing the pressure loss of the packed bed from increasing,
A stable deodorizing operation can be achieved.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view illustrating a circulation type sprinkling type deodorization tower used in Example 1 of the present invention.

FIG. 2 is a schematic explanatory view illustrating a circulation type sprinkling type deodorization tower used in Example 2 of the present invention.

FIG. 3 is a schematic explanatory view illustrating a conventional circulation type sprinkling type deodorization tower.

[Explanation of symbols]

 1: Odor gas inflow 2: Deodorization gas outflow 3: Deodorization tower 4: Packed bed 5: Water sprinkler 6: Reservoir 7: Circulation pump

Claims (6)

[Claims] 1. A scale inhibitor comprising a compound represented by the following chemical formula (1). Embedded image 2. The scale inhibitor according to claim 1, further comprising at least one of polyacrylic acid and a copolymer thereof, and polymaleic acid and a copolymer thereof. 3. In a dewatering tower of a circulating water spray system or a transient water spray system using sodium hypochlorite as a washing liquid, a compound represented by the following chemical formula (1) is added to water spray to reduce scale-causing substances. A scale adhesion preventing method comprising preventing adhesion to a filler. Embedded image 4. The method according to claim 3, wherein the amount of the compound represented by the chemical formula (1) added to the water spray is 5 to 500 mg / liter. 5. The method according to claim 3, wherein at least one of polyacrylic acid and a copolymer thereof and polymaleic acid and a copolymer thereof are added. 6. A filling layer for deodorizing odor gas inside a deodorizing device having an odor gas inlet and a deodorizing gas outlet, a watering device for watering an upper part of the filling layer,
In a deodorizing device provided with a water storage section below the packed bed,
A deodorizing device in which scale is prevented from adhering, wherein the water spraying device has a means for passing a cleaning solution containing a compound represented by the following chemical formula (1). Embedded image