WO2006109546A1 - 水処理剤および水処理方法 - Google Patents
水処理剤および水処理方法 Download PDFInfo
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- WO2006109546A1 WO2006109546A1 PCT/JP2006/306064 JP2006306064W WO2006109546A1 WO 2006109546 A1 WO2006109546 A1 WO 2006109546A1 JP 2006306064 W JP2006306064 W JP 2006306064W WO 2006109546 A1 WO2006109546 A1 WO 2006109546A1
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- Prior art keywords
- boiler
- water
- heat transfer
- water treatment
- transfer surface
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Classifications
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
- C23F11/00—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent
- C23F11/08—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids
- C23F11/18—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids using inorganic inhibitors
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
- C23F14/00—Inhibiting incrustation in apparatus for heating liquids for physical or chemical purposes
- C23F14/02—Inhibiting incrustation in apparatus for heating liquids for physical or chemical purposes by chemical means
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/58—Treatment of water, waste water, or sewage by removing specified dissolved compounds
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F5/00—Softening water; Preventing scale; Adding scale preventatives or scale removers to water, e.g. adding sequestering agents
- C02F5/08—Treatment of water with complexing chemicals or other solubilising agents for softening, scale prevention or scale removal, e.g. adding sequestering agents
- C02F5/10—Treatment of water with complexing chemicals or other solubilising agents for softening, scale prevention or scale removal, e.g. adding sequestering agents using organic substances
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F5/00—Softening water; Preventing scale; Adding scale preventatives or scale removers to water, e.g. adding sequestering agents
- C02F5/08—Treatment of water with complexing chemicals or other solubilising agents for softening, scale prevention or scale removal, e.g. adding sequestering agents
- C02F5/10—Treatment of water with complexing chemicals or other solubilising agents for softening, scale prevention or scale removal, e.g. adding sequestering agents using organic substances
- C02F5/12—Treatment of water with complexing chemicals or other solubilising agents for softening, scale prevention or scale removal, e.g. adding sequestering agents using organic substances containing nitrogen
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
- F24H9/00—Details
- F24H9/0005—Details for water heaters
- F24H9/0042—Cleaning arrangements
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
- C02F2103/02—Non-contaminated water, e.g. for industrial water supply
- C02F2103/023—Water in cooling circuits
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2303/00—Specific treatment goals
- C02F2303/08—Corrosion inhibition
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F9/00—Multistage treatment of water, waste water or sewage
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F19/00—Preventing the formation of deposits or corrosion, e.g. by using filters or scrapers
Definitions
- the present invention relates to a water treatment agent and a water treatment method, and more particularly to a water treatment agent capable of preventing overall corrosion and local corrosion of a heat transfer surface of a boiler water pipe and obtaining excellent heat transfer characteristics, and the permanent treatment.
- the present invention relates to a water treatment method using an agent.
- a boiler is a device that generates steam by being widely used as an energy supply facility for heating and power generation.
- the inner surface of the water tube that generates steam in the boiler (the heat transfer surface of the boiler water tube) is in a high-temperature and high-pressure environment, and this heat transfer surface contains calcium contained in the water supplied to the boiler (boiler feed water).
- Such components adhere to the scale (scaling) or corrode with boiler feed water.
- water treatment agent is used to prevent scaling of the heat transfer surface.
- water treatment agent When added to the water supply, it was not sufficient to prevent corrosion of the heat transfer surface of the water pipe, even though scaling of the heat transfer surface could be prevented.
- a water treatment agent when added to boiler feed water for the purpose of preventing corrosion of the heat transfer surface, it is not sufficient to prevent scaling of the heat transfer surface even though it can prevent corrosion of the heat transfer surface. .
- silica is used as a water treatment agent that can balance scaling and corrosion prevention of the heat transfer surface at the same time, in order to suppress corrosion and scale formation on the heat transfer surface caused by moisture.
- a pH adjusting agent, and a water treatment agent comprising a scale inhibitor has been proposed (see Japanese Patent Laid-Open Publication No. 2 0 3 -1 5 9 5 9 7).
- the water treatment agent described in Japanese Patent Laid-Open No. 2 0 0 3-1 5 9 5 9 7 uses a silica component and a pH adjusting agent to prevent heat transfer on the heat transfer surface of the boiler water pipe.
- a silica layer for preventing corrosion and an iron hydroxide layer are formed on the surface.
- iron hydroxide layer for example, iron oxide hydroxide
- the thermal conductivity of the corrosion product is small, so that there is a problem that the heat transfer characteristics of the boiler deteriorate. If the silica layer and the iron hydroxide layer cannot cover the entire heat transfer surface substantially uniformly, local corrosion (pitting corrosion) may occur on the heat transfer surface. If the heat transfer surface is locally corroded, there may be a hole penetrating the boiler water pipe, causing a problem that water leaks from the hole into the boiler furnace. Disclosure of the invention
- An object of the present invention is to provide a water treatment agent capable of preventing overall corrosion and local corrosion of a heat transfer surface of a boiler water pipe and obtaining excellent heat transfer characteristics, and a water treatment method using the water treatment agent.
- a film capable of suppressing corrosion is formed on the heat transfer surface of the boiler water pipe by the film forming agent, dissolved oxygen in the boiler feed water is removed by the oxygen absorber, and the scale of the heat transfer surface of the boiler water pipe is further reduced.
- the scale is prevented by the scale inhibitor, and the pH of the boiler feedwater is adjusted to pH, which prevents overall corrosion and local corrosion of the heat transfer surface of the boiler water pipe and provides excellent heat transfer characteristics. .
- the film forming agent is composed of at least one or more of silica, sodium silicate, sodium silicate, orthokeate, and polycatenate.
- the film that can suppress corrosion on the heat transfer surface of the boiler water pipe is one of the film forming agents silica, sodium silicate, potassium silicate, orthokeate, and polycaate. Since it is formed of at least one type or two or more types, it is possible to further prevent overall corrosion and local corrosion of the heat transfer surface of the boiler water pipe and to obtain excellent heat transfer characteristics.
- the oxygen scavenger comprises at least one or more of vitamin C and salts thereof, tannin, saccharide type oxygen scavenger, erythorbic acid and salts thereof, and sulfites.
- vitamin C and its salts are used as oxygen scavengers because it can remove oxygen dissolved in boiler feedwater by its strong reducing power and it has no toxicity like hydrazine. It is. Boiler feed water from which dissolved oxygen has been removed has less corrosive action on the heat transfer surface of the boiler water pipe.
- dissolved oxygen in the boiler feedwater is vitamin C and its salts, tannins, sugar-type oxygen scavengers, erythorbic acid and Since it is removed by a non-toxic oxygen scavenger such as an oxygen scavenger consisting of at least one or two or more of its salts and sulfites, it further increases the overall corrosion and local corrosion of the heat transfer surface of the boiler water pipe. In addition to preventing it, excellent heat transfer characteristics can be obtained.
- the scale inhibitor is composed of at least one or more of citrate, ethylenediaminetetraacetic acid and its salt, polyacrylic acid and its salt, polymaleic acid and its salt.
- the scale inhibitor is used because it can prevent the scale from adhering to the heat transfer surface of the boiler water pipe (scaling). That is, when queic acid, ethylenediaminetetraacetic acid and their salts are used for this scale inhibitor, calcium ions and magnesium ions contained in boiler feed water are chelated by this scale inhibitor, It becomes impossible to adhere to the heat transfer surface of the boiler water pipe as a scale. In addition, when polyacrylic acid, polymaleic acid, etc. are used as the scale inhibitor, the growth of scale crystal nuclei formed by calcium ions and magnesium ions is impeded, and the heat transfer surface of the boiler water tube It cannot adhere as a scale.
- the scaling of the heat transfer surface of the boiler water pipe is at least one or more of citrate, ethylenediaminetetraacetic acid and its salt, polyacrylic acid and its salt, polymaleic acid and its salt. It is prevented with a scale inhibitor consisting of In this way, scaling of the heat transfer surface of the boiler water pipe is prevented by the scale inhibitor, such as ethylenediaminetetraacetic acid and its salts, so that it is possible to prevent general corrosion and local corrosion of the heat transfer surface of the boiler water pipe. In both cases, more excellent heat transfer characteristics can be obtained.
- the PH adjuster is composed of at least one or more of alkali metal hydroxides such as sodium hydroxide and lithium hydroxide.
- this pH adjusting agent is used to adjust the pH of boiler feed water to the alkali side in order to prevent corrosion of the heat transfer surface of the boiler water pipe.
- the pH of boiler feedwater is determined by a pH regulator comprising at least one or more of alkali metal hydroxides such as sodium hydroxide and potassium hydroxide. pH adjusted.
- the pH of the boiler feed water is adjusted by a pH adjusting agent such as sodium hydroxide, so that overall corrosion and local corrosion of the heat transfer surface of the boiler water pipe are prevented and excellent heat transfer is achieved. Thermal properties can be obtained.
- the object of the present invention is to adjust the water treatment agent to a predetermined concentration, detect the siri force concentration dissolved in the water supply tank and the amount of dissolved oxygen, and supply the water treatment tank to the water supply tank.
- a water treatment method characterized by comprising a step of controlling the amount of the water treatment agent.
- FIG. 1 is a schematic configuration diagram of a steam boiler apparatus according to a second embodiment of the present invention.
- the present invention comprises a composition in which water is a main component, and a film forming agent that forms a film on the heat transfer surface of a boiler water pipe, an oxygen scavenger, a scale inhibitor, and a pH adjusting agent are added to the water. It is realized by doing.
- the film-forming agent for this water treatment agent there are at least one kind or two or more known ones such as silica (anhydrous caustic acid), sodium silicate, potassium silicate, orthosilicate, and polycatenate. Used.
- This film-forming agent is adsorbed on the heat transfer surface of the boiler water pipe to form a film, and the heat transfer surface of the boiler water pipe is covered with this film.
- the film formed by this film-forming agent acts as a barrier layer (shielding layer) by covering the heat transfer surface of the boiler water pipe, and acts as a protective film against corrosion. Corrosion is suppressed on the heat transfer surface of the boiler water pipe.
- the oxygen scavenger used together with this film forming agent is at least one known one such as vitamin C and its salt, tannin, sugar-type oxygen scavenger, erythorbic acid and its salt, and sulfite. Used in two or more species.
- This oxygen scavenger can remove oxygen dissolved in boiler feed water without toxicity like hydrazine.
- the oxygen dissolved in the boiler feedwater acts as an oxidizer that corrodes the heat transfer surface of the boiler water pipe. For this reason, when oxygen dissolved in boiler feedwater is removed by the oxygen scavenger, the oxidant concentration in the boiler feedwater is lowered, so that overall corrosion on the heat transfer surface of the boiler water pipe is prevented.
- the material used for the heat transfer surface of the boiler water pipe for example, charcoal
- the film formed on the heat transfer surface of the boiler water pipe is formed, for example, by a force component of the silicon being adsorbed on the surface of the carbon steel or iron oxide hydroxide formed on the surface of the carbon steel.
- crevice corrosion is localized corrosion such as pitting corrosion (which means that corrosion on the metal surface is not uniform, but is concentrated locally) is general corrosion (which means corrosion that occurs almost uniformly on the metal surface). It is known that it is easy to live in an environment where it is difficult to occur. Since the general corrosion occurs almost uniformly on the metal surface, the metal surface is not locally corroded, whereas the local corrosion is totally suppressed by the passive film and protective film. (Sound film is formed and overall corrosion is suppressed). This is because the film defect part is more easily corroded than the sound film part, and the film defect part is locally concentrated and corroded.
- the defective portion of the film forms a local battery with the healthy portion of the film
- the defective portion of the film is an anode electrode of the local battery (the negative electrode of the battery, oxidation reaction occurs, and the metal is dissolved, that is, corroded.
- the sound coating part of the local battery is the power This is because a reduction reaction occurs and the metal is not dissolved, that is, it is not corroded.
- an oxygen concentration cell is formed, and the cell reaction proceeds.
- oxygen concentration cells generally have a higher corrosion rate as the ratio of the amount of oxygen (concentration) between the healthy film part that forms a force sword and the defective film part that forms an anode increases (the battery electromotive force increases). ing. In other words, this means that if the ratio of the amount of oxygen (concentration) between the healthy film part and the film defect part can be reduced, local corrosion due to the film defect part can be prevented (suppressed). is doing.
- the water treatment agent of the present invention is dissolved in the boiler feed water by the oxygen scavenger even if the film on the heat transfer surface of the boiler water pipe formed by the film forming agent forms a film defect part for some reason. This reduces the amount of oxygen (concentration) that is present, making it difficult to form oxygen concentration cells, thus preventing local corrosion. That is, if the amount of oxygen (concentration) dissolved in the boiler feedwater decreases, the absolute amount of oxygen (concentration) in the healthy film portion will decrease, so the amount of oxygen (concentration in the healthy film portion and film defect portion) ) Ratio is reduced, the electromotive force of the oxygen concentration cell is reduced and local corrosion can be prevented.
- the water treating agent of the present invention contains a scale inhibitor.
- the scale inhibitor at least one kind or two or more kinds of known substances such as citrate, ethylenediaminetetraacetic acid and salts thereof, polyacrylic acid, and polyphosphoric acid are used.
- cenoic acid, ethylenediaminetetraacetic acid and its salt (EDTA-Na) are used as a scale inhibitor, calcium and magnesium ions contained in boiler feedwater are chelated by this scale inhibitor.
- the scale becomes difficult to attach to the heat transfer surface of the boiler water pipe.
- polyacrylic acid and its salt, polymaleic acid and its salt, etc. are used as a scale inhibitor, a scale formed by calcium ions or magnesium ions is used. The growth of crystal nuclei is hindered, making it difficult for scale to adhere to the heat transfer surface of the boiler water tube. Thus, if scale is difficult to adhere to the heat transfer surface of the boiler water tube, The boiler can be operated with excellent heat transfer characteristics.
- this water treatment agent contains a pH adjusting agent.
- a pH adjusting agent at least one or more known substances such as alkali metal hydroxides such as sodium hydroxide and potassium hydroxide are used.
- This pH adjuster adjusts the pH of boiler feedwater to the Al force side to prevent corrosion of the heat transfer surface of the boiler water pipe.
- the film-forming agent, oxygen scavenger, scale inhibitor and pH adjusting agent in the present invention can be supplied as individual chemicals in a form dissolved in water. Considering the labor of (drug injection), it is desirable to make it a one-part preparation.
- Vitamin C [g] 2.5 5.0 7.5 0.0 0.0
- the water treatment agent of Example 1 shown in Table 1 is a predetermined amount of a film forming agent, an oxygen scavenger, a scale inhibitor, and a pH adjusting agent in pure water per 100 g of the water treatment agent. It is a blend. That is, the water treatment agent of Example 1 is sodium silicate (Wako Pure Chemicals, special grade reagent) 1.26 g as a film forming agent, and vitamin C (L-ascorbic acid) (Wako Jun) as an oxygen scavenger. 2.5 g and ED TA— 2 N a (Wako Pure Chemical, special grade reagent) 0.4 g and pH adjusting agent, sodium hydroxide (Wako Pure Chemical) 4. Special grade reagent) 4.
- the water softened as the boiler water supply is made by artificially adjusting the softened water of Osaka City, with a pH of 7.5 and an electrical conductivity of 25 mS / m, M alkaline degree SO mg Z l - those having C a C_ ⁇ 3, water hardness force S lmg / Li Tsu preparative Honoré one C a C_ ⁇ 3.
- the water softened water used in the examples and comparative examples of this water treatment agent is water prepared by artificially adjusting the softened water in Osaka City, and the description of this water softened water is as follows. The following is omitted.
- the water treatment agent of Example 2 is a film forming agent, oxygen scavenger, scale inhibitor, and pH adjustment in 100 g of water treatment agent.
- a predetermined amount of the agent is blended. That is, the water treatment agent of Example 2 was sodium silicate (Wako Pure Chemicals, special grade reagent) 5.4 6 g as the film forming agent, and vitamin C (L-ascorbic acid) as the oxygen scavenger. (Wako Pure Chemicals, special grade reagent) 5.
- the water treatment agent of Example 3 is the same as the water treatment agent of Example 1,
- the total amount of the agent is a mixture of a predetermined amount of a film forming agent, an oxygen scavenger, a scale inhibitor, and a pH adjusting agent in 100 g of pure water. That is, the water treatment agent of Example 3 was obtained by using 9.66 g of sodium silicate as a film forming agent and vitamin C (L-ascorbic acid) (Wako Pure Chemicals, special grade test) as an oxygen scavenger. 7.5 g and scale inhibitor EDTA-2 Na (Wako Pure Chemicals, special grade reagent) 0.4 g and pH modifier sodium hydroxide (Wako Pure Chemicals, special grade reagent) 4. O g was blended, and 50 O mg per liter was added to softened water.
- the water treatment agent of Comparative Example 1 is a mixture of a predetermined amount of a film-forming agent, a scale inhibitor, and a pH adjusting agent in pure water per 100 g of the total amount of the water treatment agent. That is, the water treatment agent of Comparative Example 1 has 0.04 g of sodium silicate (Wako Pure Chemicals, special grade reagent) as the film forming agent and ED TA-2 Na (Wako Pure Chemicals) as the scale inhibitor. (Special grade reagent) 0.4 g and pH adjuster with sodium hydroxide (Wako Pure Chemicals, special grade reagent) 4. O g is mixed into soft water for 1 liter. 50 O mg was added per unit.
- the water treatment agent in Comparative Example 2 contains a predetermined amount of a film forming agent, a scale inhibitor, and a pH adjusting agent in 100 g of the total amount of water treatment agent. It is a thing.
- the water treatment agent of Comparative Example 2 has 21.5 g of sodium silicate (Wako Pure Chemicals, special grade reagent) as the film forming agent and ED TA-2 N a (Wako Pure Chemicals) as the scale inhibitor. Medicine, special grade reagent) 0.4 g and pH adjusting agent sodium hydroxide (Wako Pure Chemicals, special grade reagent) 4. O g is blended in softened water 1 500 mg was added per liter.
- This experimental once-through boiler was operated continuously for 48 hours because the scale adhesion characteristics and corrosion evaluation on the heat transfer surface of the boiler water pipe were as close as possible to those of the actual machine.
- the scale adhesion characteristics on the heat transfer surface of the boiler water pipe are as follows: Boiler water (which is heated by the water in the boiler water pipe) is collected 24 hours after the start of boiler operation, and the Ca concentration in the boiler water is measured. Measurements were made to evaluate the solubility of C a, and after completion of the operation for 48 hours, an evaluation boiler water pipe was extracted from the experimental once-through boiler, and the heat transfer surface of the boiler water pipe was observed and evaluated. Further, the corrosion on the heat transfer surface of the boiler water tube was evaluated by observing the heat transfer surface of the boiler water tube for evaluation.
- boiler water was sampled, and the Ca concentration in the collected boiler water was measured by an ICP emission spectrometer. From this measured Ca concentration, C a The solubility is evaluated and the scale adhesion characteristics on the heat transfer surface of the boiler water pipe are evaluated.
- the evaluation of scale adhesion characteristics by evaluating Ca solubility focuses on the fact that when Ca is deposited as a scale on the heat transfer surface of the boiler water pipe, the Ca concentration of boiler water, that is, the Ca solubility, decreases. It was made. Specifically, boiler feedwater with a Ca concentration of 1. O mg Z liters C a C 0 3 was used for experimental once-through pouring under conditions where the boiler blow rate was 10%.
- the scale adhesion characteristics are evaluated by observing with a naked eye and a loupe.
- the scale adhesion characteristics can also be evaluated from the thickness of the scale by measuring the thickness of the scale attached to the heat transfer surface of the boiler water pipe using a film thickness meter.
- Table 1 shows that the boiler feed water to which a predetermined amount of the water treatment agent shown in Examples 1 to 3 and Comparative Examples 1 to 2 was added was measured at 24 hours after the start of boiler operation.
- the Ca water solubility as a concentration is shown.
- the Ca water solubility to which a predetermined amount of the water treatment agents of Examples 1 to 3 and Comparative Example 1 was added had a Ca solubility of 10 mg Z liter or more.
- the boiler feed water to which a predetermined amount of the water treatment agent of Comparative Example 2 was added had a Ca solubility of 10 mg or less.
- the Ca solubility was low because the concentration of sodium silicate in the boiler feed water was high, and the silica component and hardness in the sodium silicate (C a This is because they are attached to the heat transfer surface of the boiler water pipe.
- the evaluation of corrosion on the heat transfer surface of the boiler water pipe was performed according to the following procedure. First, the boiler operation is stopped after 48 hours, the boiler water pipe is removed from the stopped boiler, and the scale is washed with water from the surface of the water pipe. Or by pickling. Next, the surface of the boiler water pipe from which the scale has been removed is visually observed with the naked eye or a magnifying glass to check for the presence of overall corrosion. Finally, regarding local corrosion, the surface of the boiler water pipe from which scale has been removed is examined by visual observation with the naked eye or a magnifying glass to determine whether pitting corrosion (also called pitting) has occurred. The maximum depth of pitting corrosion is determined using an optical displacement meter.
- Table 1 shows the presence or absence of general corrosion on the heat transfer surface of the boiler water pipe, the presence or absence of local corrosion, and the hole for the boiler feed water to which a predetermined amount of the water treatment agent shown in Examples 1 to 3 and Comparative Examples 1 to 2 was added. Each maximum eclipse depth is indicated.
- the boiler feed water to which a predetermined amount of the water treatment agents of Examples 1 to 3 and Comparative Example 2 are added prevents the overall corrosion and local corrosion of the heat transfer surface of the boiler water pipe. It was. On the other hand, in the boiler feed water to which a predetermined amount of the water treatment agent of Comparative Example 1 was added, general corrosion was prevented, but local corrosion of the heat transfer surface of the boiler water pipe was not prevented.
- a film capable of suppressing corrosion is formed on the heat transfer surface of the boiler water pipe by the film forming agent, and the dissolved oxygen in the boiler feed water is deoxygenated.
- the scale of the heat transfer surface of the boiler water pipe is prevented by the scale inhibitor, and the pH of the boiler feed water is adjusted to pH, so that the entire surface of the heat transfer surface of the boiler water pipe is corroded and localized. In addition to preventing corrosion, excellent heat transfer characteristics can be obtained.
- FIG. Figure 1 shows the schematic configuration of the steam boiler unit.
- a steam boiler device 1 is composed of a water supply unit 2, a steam boiler 3, a water treatment agent supply unit 4, and a control unit 5.
- the water supply unit 2 is composed of various pretreatment devices that supply boiler water to the steam boiler 3, and includes a water softener 2 1, a deaeration device 2 2, A water supply tank 2 3 is provided.
- the water softener 21 is a device for softening (softening) replenishing water such as tap water or industrial water supplied from the outside through the water supply passage W 1.
- the reason why the makeup water is softened is to remove calcium ions and magnesium ions contained in the makeup water.
- the reason why calcium ions and magnesium ions are removed is to prevent them from adhering as a scale to the heat transfer surface of the boiler water pipe and deteriorating the heat transfer characteristics.
- the captured water (soft water) softened by the water softener 21 is degassed by the degassing device 22.
- the deaerator 22 is a device that mainly removes dissolved oxygen in soft water in advance because dissolved oxygen in soft water makes the heat transfer surface of the boiler water pipe susceptible to corrosion.
- a gas separation membrane a device that continuously removes oxygen by heating, a batch type device that uses reduced pressure or ultrasonic waves, and the like are used.
- an apparatus using a gas separation membrane which is a membrane that allows gas to pass but does not pass liquid, is preferable because it is easy to operate, can be stably operated continuously, and costs are low.
- water that has been softened flows inside the gas separation membrane, and when the outside of the membrane is brought into a vacuum state, the gas contained in the soft water is removed from the membrane.
- the air can be exhausted to the outside of the membrane and the soft water can be degassed.
- the soft water from which the dissolved oxygen has been removed by the deaerator 22 is stored in the water supply tank 23.
- Boiler feed water to be supplied to the steam boiler 3 is stored in the feed water tank 2 3, and a detection unit 24 is provided for measuring and detecting the amount of dissolved oxygen in the boiler feed water.
- a detection unit 24 is provided for measuring and detecting the amount of dissolved oxygen in the boiler feed water.
- soft water deaerated by the deaerator 2 2 and condensate obtained by heat exchange of steam generated by the steam boiler 3 in the load device (not shown) are condensate recovery passages (illustration).
- This water treatment agent is the water treatment agent described in the embodiment of the present invention, a film forming agent mainly containing water and forming a film on the heat transfer surface of the boiler water pipe, and an oxygen scavenger. And a scale inhibitor and a pH adjusting agent. Therefore, when this water treatment agent is supplied to the boiler feed water, corrosion of the heat transfer surface of the boiler water pipe and adhesion of scale can be prevented.
- This boiler feedwater is supplied from the feedwater tank 23 to the steam boiler 3 via the feedwater channel W3 by the feedwater pump P2.
- the silica concentration detected by the detection unit 24 is the concentration as silica (silicon dioxide), and is measured and detected according to the molybdenum yellow absorptiometry described in JISK 0 1 0 1 .
- the dissolved oxygen amount is measured and detected according to the industrial water test method described in JIS 0 1 0 1.
- the steam boiler 3 generates steam by heating boiler feed water, and is in a high temperature and high pressure environment.
- the boiler water pipe (not shown) receives radiant heat directly from the heating source on the outer surface side of the pipe, and high-temperature and high-pressure boiler feed water or steam flows on the inner surface side of the pipe (heat transfer surface of the boiler water pipe).
- the boiler water pipe may be corroded or scales attached, so the steam boiler 3 may not be able to operate stably for a long period of time. There is. Therefore, the quality control of boiler feedwater is an important item, and there is a need for a boiler feedwater treatment method as shown in this example.
- the water treatment method of this embodiment when the silica concentration dissolved in the boiler feed water stored in the feed water tank 23 changes in the dissolved oxygen amount, the water treatment is adjusted to a predetermined concentration in advance.
- the agent tank 4 1 Stored in the agent tank 4 1
- the water treatment agent is supplied to the water supply tank 23 in response to the fluctuation.
- the supply amount of the water treatment agent supplied to the water supply tanks 23 and 3 is controlled in accordance with fluctuations in the amount of dissolved oxygen.
- the supply amount of the water treatment agent is controlled by controlling the discharge amount of the chemical supply pump P 1 of the water treatment agent supply unit 4 by the control unit 5 described later.
- the water treatment agent supply unit 4 includes a water treatment agent tank 4 1 storing the above-described water treatment agent, and a chemical supply pump P 1 for supplying the water treatment agent tank 41 to the water supply tank 23. Yes.
- the water treatment agent tank 41 stores a water treatment agent adjusted in advance to a predetermined concentration.
- the fluctuation of silica concentration in boiler feedwater is detected by detecting the silica concentration in boiler feedwater and the amount of dissolved oxygen in the detection unit 24 provided in the feedwater tank 23. N is determined by the control unit 5 based on the amount of dissolved oxygen.
- control unit 5 is electrically connected to each device constituting the water supply device unit 2 and the water treatment agent supply unit 4. Specifically, the control unit 5 is electrically connected to the detection unit 24 and the chemical supply pump P 1 provided in the boiler water supply tank 23.
- the control unit 5 is configured as a logic circuit centered on a microcomputer.
- the control unit 5 inputs information on the silica concentration and the dissolved oxygen amount from the detection unit 24, and outputs a control signal for the discharge amount of the drug supply pump P 1 based on this information. Control the discharge rate of P1.
- the amount of discharge of the chemical supply pump P 1 is controlled because the scale tends to adhere to the heat transfer surface of the boiler water pipe as the amount of water treatment agent supplied to the water supply tank 2 3 increases. This is to prevent the heat transfer characteristics from deteriorating.
- water treatment supplied to the water tank 2 3 If the supply amount of the agent is reduced, the thickness of the silicon force layer or iron hydroxide layer formed on the heat transfer surface of the boiler water pipe will be reduced, and the heat transfer surface of the boiler water pipe will be totally corroded. Is to prevent. In addition, if the thickness distribution of the silli force layer or iron hydroxide layer formed on the heat transfer surface of the boiler water pipe becomes uneven, the heat transfer surface of the boiler water pipe is likely to be locally corroded. Because.
- the film forming agent that forms a film on the heat transfer surface of the boiler water pipe, Oxygen agent, scale inhibitor, and pH adjuster are blended, and the amount of water treatment agent adjusted to a predetermined concentration is controlled according to the above fluctuations. By doing so, it is possible to prevent general corrosion and local corrosion on the heat transfer surface of the boiler water pipe and to obtain excellent heat transfer characteristics.
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Organic Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Hydrology & Water Resources (AREA)
- Materials Engineering (AREA)
- Water Supply & Treatment (AREA)
- Life Sciences & Earth Sciences (AREA)
- Environmental & Geological Engineering (AREA)
- Physics & Mathematics (AREA)
- Inorganic Chemistry (AREA)
- Thermal Sciences (AREA)
- Combustion & Propulsion (AREA)
- General Engineering & Computer Science (AREA)
- Preventing Corrosion Or Incrustation Of Metals (AREA)
- Removal Of Specific Substances (AREA)
- Treatment Of Water By Oxidation Or Reduction (AREA)
Abstract
Description
Claims
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
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CA002603426A CA2603426A1 (en) | 2005-03-30 | 2006-03-20 | Water treatment and method of water treatment |
Applications Claiming Priority (2)
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JP2005-099551 | 2005-03-30 | ||
JP2005099551A JP2006274427A (ja) | 2005-03-30 | 2005-03-30 | 水処理剤および水処理方法 |
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WO2006109546A1 true WO2006109546A1 (ja) | 2006-10-19 |
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ID=37086828
Family Applications (1)
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PCT/JP2006/306064 WO2006109546A1 (ja) | 2005-03-30 | 2006-03-20 | 水処理剤および水処理方法 |
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Country | Link |
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JP (1) | JP2006274427A (ja) |
KR (1) | KR20070116022A (ja) |
CN (1) | CN101151400A (ja) |
CA (1) | CA2603426A1 (ja) |
WO (1) | WO2006109546A1 (ja) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2009285522A (ja) * | 2008-05-27 | 2009-12-10 | Miura Co Ltd | 逆浸透膜装置 |
JP2011236481A (ja) * | 2010-05-12 | 2011-11-24 | Miura Co Ltd | 金属の洗浄方法 |
CN113248030A (zh) * | 2021-05-25 | 2021-08-13 | 山东上远环保科技有限公司 | 一种复合型无磷锅炉水处理剂 |
Families Citing this family (19)
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JP5019168B2 (ja) * | 2007-05-08 | 2012-09-05 | 三浦工業株式会社 | 薬剤注入方法 |
JP2009285530A (ja) * | 2008-05-27 | 2009-12-10 | Kurita Water Ind Ltd | ボイラ装置用水処理剤及びボイラ装置の水処理方法 |
KR101493381B1 (ko) | 2008-08-05 | 2015-02-13 | 쿠리타 고교 가부시키가이샤 | 보일러수 처리제 및 수처리방법 |
JP5273378B2 (ja) | 2009-03-25 | 2013-08-28 | 三浦工業株式会社 | 蒸気ボイラ装置およびその運転方法 |
JP5510123B2 (ja) * | 2010-06-30 | 2014-06-04 | 三浦工業株式会社 | 蒸気ボイラの運転方法 |
JP5862193B2 (ja) * | 2011-10-18 | 2016-02-16 | 栗田工業株式会社 | 蒸気発生器の水側缶内における鉄スケール防止方法 |
AR090505A1 (es) * | 2012-04-09 | 2014-11-19 | Nalco Co | Metodo y dispositivo para la prevencion de la corrosion en sistemas de agua caliente |
CN103351031A (zh) * | 2013-05-10 | 2013-10-16 | 湖北中烟工业有限责任公司 | 延长再造烟叶生产循环水使用周期的净化剂及其使用方法 |
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CN104628154A (zh) * | 2013-11-09 | 2015-05-20 | 西安润达化工科技有限公司 | 一种锅炉水处理剂 |
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JP6416023B2 (ja) * | 2015-03-13 | 2018-10-31 | 株式会社東芝 | スケール抑制方法および装置 |
JP6866695B2 (ja) * | 2017-03-07 | 2021-04-28 | 三浦工業株式会社 | 水処理剤、スケール除去方法、及びスケール抑制方法 |
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JP6885266B2 (ja) * | 2017-08-29 | 2021-06-09 | 三浦工業株式会社 | 亜硫酸系水処理剤及び水処理方法 |
CN107673489A (zh) * | 2017-11-14 | 2018-02-09 | 昌邑市龙港无机硅有限公司 | 一种循环水用缓蚀阻垢剂 |
CN108101237A (zh) * | 2017-12-08 | 2018-06-01 | 亿利洁能科技(颍上)有限公司 | 一种煤炭锅炉水处理剂及利用方法 |
CN110952103A (zh) * | 2019-12-06 | 2020-04-03 | 万华化学集团股份有限公司 | 一种用于含氧盐水中碳钢缓蚀剂及其制备方法 |
JP7083365B2 (ja) * | 2020-03-12 | 2022-06-10 | 栗田工業株式会社 | ボイラにおける蒸発管の腐食疲労の抑制方法 |
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JP2003043028A (ja) * | 2001-07-31 | 2003-02-13 | Miura Co Ltd | 成分濃度の測定方法および測定装置 |
JP2003120904A (ja) * | 2001-08-09 | 2003-04-23 | Miura Co Ltd | 蒸気ボイラ装置用水処理剤 |
JP2003159597A (ja) * | 2001-11-28 | 2003-06-03 | Miura Co Ltd | 水処理剤 |
-
2005
- 2005-03-30 JP JP2005099551A patent/JP2006274427A/ja not_active Withdrawn
-
2006
- 2006-03-20 CN CNA200680010488XA patent/CN101151400A/zh active Pending
- 2006-03-20 WO PCT/JP2006/306064 patent/WO2006109546A1/ja active Application Filing
- 2006-03-20 KR KR1020077022065A patent/KR20070116022A/ko not_active Application Discontinuation
- 2006-03-20 CA CA002603426A patent/CA2603426A1/en not_active Abandoned
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2003043028A (ja) * | 2001-07-31 | 2003-02-13 | Miura Co Ltd | 成分濃度の測定方法および測定装置 |
JP2003120904A (ja) * | 2001-08-09 | 2003-04-23 | Miura Co Ltd | 蒸気ボイラ装置用水処理剤 |
JP2003159597A (ja) * | 2001-11-28 | 2003-06-03 | Miura Co Ltd | 水処理剤 |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2009285522A (ja) * | 2008-05-27 | 2009-12-10 | Miura Co Ltd | 逆浸透膜装置 |
JP2011236481A (ja) * | 2010-05-12 | 2011-11-24 | Miura Co Ltd | 金属の洗浄方法 |
CN113248030A (zh) * | 2021-05-25 | 2021-08-13 | 山东上远环保科技有限公司 | 一种复合型无磷锅炉水处理剂 |
Also Published As
Publication number | Publication date |
---|---|
KR20070116022A (ko) | 2007-12-06 |
CA2603426A1 (en) | 2006-10-19 |
CN101151400A (zh) | 2008-03-26 |
JP2006274427A (ja) | 2006-10-12 |
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