JPH0593286A - Method and agent for preventing corrosion of steam and condensate lines - Google Patents

Abstract

PURPOSE:To prevent the corrosion of steam and condensate lines with a corrosion inhibitor prepared from vitamin A and/or vitamin E and a surfactant. CONSTITUTION:A corrosion inhibitor contg. at least one kind selected from among vitamin A (vitamin A1, vitamin A fatty acid ester, etc.) and vitamin E (alpha-tocopherol, beta-tocopherol, etc.) and a surfactant (polyoxyethylene alkyl ester, etc.) is prepared. This agent is added into a boiler to prevent the corrosion of the pipeline and equipment of the steam and condensate lines.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a safe method for preventing the occurrence of corrosion in steam and condensate piping and equipment, and a chemical agent used therefor.

[0002]

2. Description of the Related Art In a steam generating device such as a boiler or a condensing can, there is a phenomenon that a metal contacting with steam or condensate is corroded due to oxygen, M-alkalinity component, etc. contained in feed water. is there. Particularly in the condensate system, carbon dioxide generated together with steam in a boiler or the like is dissolved again in water when the steam is condensed, and the pH of condensed water (condensate) is lowered, so that severe corrosion often occurs in pipes and equipment. Conventionally, as a method of preventing such corrosion, in addition to ion exchange treatment and degassing treatment for the purpose of decarboxylation of feed water, pH adjustment with strong base amines such as morpholine, and long-chain such as octadecylamine It has been practiced to add an aliphatic amine into a boiler to form a protective film on the inner surfaces of steam and condensate piping and equipment.

By the way, when the steam generated in a boiler or the like is used in the processing of food or the manufacturing process of pharmaceuticals, or when it is used for humidifying a building air conditioner, the safety of steam is strongly required in terms of hygiene. Be done. The amine-type chemicals described above enter the steam though they are small in amount due to evaporation, so even if the substance is approved as an additive for boilers in the US FDA standards, the purpose of use of the generated steam and the steam The concentration of the drug inside is also limited, and it cannot be said that it is always sufficient in terms of safety. Therefore, when safety of steam is required, even when there is concern about corrosion in steam and condensate piping and equipment,
To ensure safety, steam was often used without chemical treatment.

[0004]

DISCLOSURE OF THE INVENTION As a result of intensive research aimed at achieving the above-mentioned object, the present inventors have found that organic substances which are indispensable for maintaining normal growth and nutrition of animals are indispensable. It has been found that, among some vitamins, vitamin A and vitamin E have a steam and condensate system anticorrosive effect. However, it was also found that these highly safe anticorrosive effects of vitamin A and vitamin E were sufficiently exhibited when added to the steam pipe, but not necessarily obtained when added to the boiler. Therefore, the present invention is
By utilizing these anticorrosive effects of vitamin A and vitamin E, by adding them in the boiler, it is possible to effectively prevent corrosion of steam and condensate piping and equipment, and also to ensure safety in terms of hygiene. It is intended to provide an agent.

[0005]

[Means for Solving the Problems] That is, the present invention is a steam- and condensate-based anticorrosive agent containing at least one compound selected from vitamin A or vitamin E and a surfactant. Further, the steam and condensate system anticorrosion method is characterized in that at least one compound selected from vitamin A or vitamin E and a surfactant are added into the boiler.

Vitamin A used in the present invention is (a) a vitamin A compound such as vitamin A ₁ (retinol), vitamin A ₂ or vitamin A ₃ , or
(B) Derivatives of the above vitamin A compounds such as vitamin A fatty acid ester, vitamin A acid, vitamin A aldehyde, etc., which may be natural products or synthetic products, or containing these compounds or derivatives, for example, liver of aquatic animals It may be fatty oil obtained from pylorus or pylorus.

Vitamin E used in the present invention
Means so-called tocopherol and its homologues,
For example, α-tocopherol, β-tocopherol, γ-
Examples thereof include tocopherol, δ-tocopherol, α-tocotrienol, β-tocotrienol, γ-tocotrienol and the like. Also, as in the case of vitamin A, oils containing these compounds, such as germ oil and soybean oil, may be used.

[0008] These vitamin A and vitamin E are ingested by humans as food ingredients on a daily basis, and also as a strengthening agent for nutritional foods, dairy products, flour, infant food, soup base, curry roux, It is a substance widely used as an additive for confectionery and the like. Since such vitamin A and vitamin E have been sufficiently studied for their safety such as their effects on the human body, they can be suitably used even when the safety of steam is important as described above.

The surfactant used in the present invention is, for example, nonionic surfactant such as polyoxyethylene alkyl ether, polyhydric alcohol higher fatty acid ester, polyoxyethylene polyhydric alcohol ether higher fatty acid ester, etc., alkyl allyl sulfone. Acid alkali salt,
Hygienic and safe from anionic surfactants such as alkyl sulfonates and higher fatty acid alkali salts, polyoxyethylene ether type organic quaternary ammonium salts, and cationic surfactants such as higher aliphatic amines. It is desirable to select one. These surfactants may be used alone or in combination of two or more.

The above-mentioned vitamin A and vitamin E may be used alone or in combination, but they are mixed with the above-mentioned surfactant or further added with water to obtain an emulsion. Such a formulation may include a solvent and the like,
Further, other types of anticorrosive agents, scale inhibitors, etc. may be blended. The ratio of the vitamin A or vitamin E to the surfactant in the thus obtained anticorrosive agent of the present invention is not particularly limited as long as it is sufficient to emulsify the vitamin A or vitamin E in water.

The anticorrosive agent of the present invention can be added by injection into steam or condensate piping, but it is more preferable from the viewpoint of hygiene to use the method of injecting into the boiler. It is preferable to appropriately determine the addition amount and the addition concentration after conducting a preliminary test in consideration of equipment conditions and usage conditions.

[0012]

The anticorrosive agent of the present invention is mixed with the boiler feed water and injected into the boiler, or directly into the boiler according to the amount of steam generated, so that the steam or condensate pipes and equipment can be effectively used. It is possible to prevent corrosion.

[0013]

EXAMPLE As shown in FIG. 1, a steam header b, a water-cooled steam condenser c connected to the steam header b, and a condensed water (condensate) tank d connected to the steam header b are connected to each other, and an electric heater e (heat transfer area 0. 67 m ² ) is submerged in water while supplying the water quality f as shown in Table 1 to the autoclave a, vapor pressure 8 kgf / cm ² , vapor generation rate 5.5 kg / h, blow rate 10%,
Condensed water tank d water temperature 70 ℃, total water supply 200L
I drove until. 15mm suspended in condensed water tank d
The corrosion weight loss of a soft steel plate of x40 mm x 2 mm was measured and the corrosion protection rate (%) was calculated. The drugs g used are shown in Table 2 respectively.
The composition is shown in Table 3, and the vapor amount is shown in Table 3 respectively.
The mixture was mixed in the feed water so as to have the ratio shown in FIG.

The results are shown in Table 3. The results are shown in Table 3. Vitamin A and Vitamin E do not exhibit an excellent anticorrosion effect unless they are directly injected into the vapor system, whereas the present invention using a surfactant together It can be seen that the anticorrosive agent exhibits a sufficient anticorrosion effect by being injected into the boiler together with water supply.

[0015]

[Table 1] Table 1 Water supply quality ──────────────────────────── pH: 7.5 Electric conductivity (μS / cm ): 200 M-alkalinity (mg CaCO ₃ / L): 48 Silica (mg SiO ₂ / L): 24 Chloride ion (mg Cl / L): 13 Total hardness (mg CaCO ₃ / L): Less than 1 ─ ────────────────────────────

[0016]

[Table 2]

[0017]

[Table 3] Table 3 ───────────────────────────────── Experimental drug addition location Addition amount Anticorrosion rate Note number ( mg / L) (%) ───────────────────────────────── 1 A Within water supply 300 78 Example 2 B 〃 〃 42 〃 3 C 〃 〃 60 〃 4 D 〃 〃 67 〃 5 E 〃 〃 71 〃 6 F 〃 〃 〃 21 Comparative example 7 F 9 〃 〃 〃 21 〃 10 〃 〃 62 〃 11 J 〃 〃 76 〃 12 K 〃 〃 68 〃 13 L 〃 〃 18 〃 77 〃 15 〃 17 〃 17 〃 17 〃 600 0 〃 18 O Steam line 〃 0 〃 ────────────────────────────── ───

[0018]

EFFECTS OF THE INVENTION Since the steam and condensate anticorrosives of the present invention use vitamin A or vitamin E and a surfactant, which have been confirmed to be safe in terms of hygiene, they can be simply added to the boiler. Excellent results can be obtained even in various usages,
The steam can be used for treating food and the like without worrying about the corrosion of the piping and the occurrence of steam pollution due to chemicals or the like.

[Brief description of drawings]

FIG. 1 is a block diagram of an apparatus for testing the effect of a steam and condensate system anticorrosive agent of the present invention.

[Explanation of symbols]

 a Autoclave device b Steam header c Water-cooled steam condenser d Condensed water tank e Electrothermal heater f Water supply g Chemicals

Claims (2)

[Claims] 1. A steam and condensate anticorrosive comprising a surfactant and at least one compound selected from vitamin A or vitamin E. 2. A steam and condensate anticorrosion method, which comprises adding at least one compound selected from vitamin A or vitamin E and a surfactant into a boiler.