CN115571964A - Chemical treatment method for corrosion prevention of metal material of cooling water system of nuclear power plant equipment - Google Patents
Chemical treatment method for corrosion prevention of metal material of cooling water system of nuclear power plant equipment Download PDFInfo
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- CN115571964A CN115571964A CN202211118812.7A CN202211118812A CN115571964A CN 115571964 A CN115571964 A CN 115571964A CN 202211118812 A CN202211118812 A CN 202211118812A CN 115571964 A CN115571964 A CN 115571964A
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- 239000000498 cooling water Substances 0.000 title claims abstract description 61
- 239000000126 substance Substances 0.000 title claims abstract description 32
- 238000000034 method Methods 0.000 title claims abstract description 28
- 238000005536 corrosion prevention Methods 0.000 title claims abstract description 16
- 239000007769 metal material Substances 0.000 title claims abstract description 16
- YNAVUWVOSKDBBP-UHFFFAOYSA-N Morpholine Chemical compound C1COCCN1 YNAVUWVOSKDBBP-UHFFFAOYSA-N 0.000 claims abstract description 74
- OAKJQQAXSVQMHS-UHFFFAOYSA-N Hydrazine Chemical compound NN OAKJQQAXSVQMHS-UHFFFAOYSA-N 0.000 claims abstract description 54
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 50
- 239000003814 drug Substances 0.000 claims abstract description 16
- 229940079593 drug Drugs 0.000 claims abstract description 12
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 10
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 10
- 239000001301 oxygen Substances 0.000 claims abstract description 10
- 230000001276 controlling effect Effects 0.000 claims abstract 2
- 230000001105 regulatory effect Effects 0.000 claims abstract 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 24
- 239000011734 sodium Substances 0.000 claims description 12
- 229910052742 iron Inorganic materials 0.000 claims description 9
- NWZSZGALRFJKBT-KNIFDHDWSA-N (2s)-2,6-diaminohexanoic acid;(2s)-2-hydroxybutanedioic acid Chemical compound OC(=O)[C@@H](O)CC(O)=O.NCCCC[C@H](N)C(O)=O NWZSZGALRFJKBT-KNIFDHDWSA-N 0.000 claims description 8
- 150000004985 diamines Chemical class 0.000 claims description 8
- IKDUDTNKRLTJSI-UHFFFAOYSA-N hydrazine monohydrate Substances O.NN IKDUDTNKRLTJSI-UHFFFAOYSA-N 0.000 claims description 8
- 238000012423 maintenance Methods 0.000 claims description 7
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 claims description 6
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 claims description 6
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 claims description 6
- 229910001385 heavy metal Inorganic materials 0.000 claims description 6
- 229910052708 sodium Inorganic materials 0.000 claims description 6
- 239000002351 wastewater Substances 0.000 claims description 6
- 239000002253 acid Substances 0.000 claims description 5
- 230000002829 reductive effect Effects 0.000 claims description 4
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 3
- KRHYYFGTRYWZRS-UHFFFAOYSA-M Fluoride anion Chemical compound [F-] KRHYYFGTRYWZRS-UHFFFAOYSA-M 0.000 claims description 3
- CLBRCZAHAHECKY-UHFFFAOYSA-N [Co].[Pt] Chemical compound [Co].[Pt] CLBRCZAHAHECKY-UHFFFAOYSA-N 0.000 claims description 3
- 239000007864 aqueous solution Substances 0.000 claims description 3
- 238000009835 boiling Methods 0.000 claims description 3
- 238000007922 dissolution test Methods 0.000 claims description 3
- 238000002360 preparation method Methods 0.000 claims 2
- 230000007797 corrosion Effects 0.000 abstract description 42
- 238000005260 corrosion Methods 0.000 abstract description 42
- 208000028659 discharge Diseases 0.000 abstract description 18
- 239000003112 inhibitor Substances 0.000 abstract description 8
- 230000000813 microbial effect Effects 0.000 abstract description 6
- 230000000694 effects Effects 0.000 description 10
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 9
- 229910052802 copper Inorganic materials 0.000 description 9
- 239000010949 copper Substances 0.000 description 9
- 229910000975 Carbon steel Inorganic materials 0.000 description 6
- 239000010962 carbon steel Substances 0.000 description 6
- 230000005764 inhibitory process Effects 0.000 description 5
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 4
- 238000001514 detection method Methods 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 239000000047 product Substances 0.000 description 4
- BPQQTUXANYXVAA-UHFFFAOYSA-N Orthosilicate Chemical compound [O-][Si]([O-])([O-])[O-] BPQQTUXANYXVAA-UHFFFAOYSA-N 0.000 description 3
- 229910019142 PO4 Inorganic materials 0.000 description 3
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 3
- ZCDOYSPFYFSLEW-UHFFFAOYSA-N chromate(2-) Chemical compound [O-][Cr]([O-])(=O)=O ZCDOYSPFYFSLEW-UHFFFAOYSA-N 0.000 description 3
- 238000001816 cooling Methods 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 239000010452 phosphate Substances 0.000 description 3
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 3
- 239000010935 stainless steel Substances 0.000 description 3
- 229910001220 stainless steel Inorganic materials 0.000 description 3
- 239000010936 titanium Substances 0.000 description 3
- 229910000570 Cupronickel Inorganic materials 0.000 description 2
- 229910000990 Ni alloy Inorganic materials 0.000 description 2
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- IOVCWXUNBOPUCH-UHFFFAOYSA-M Nitrite anion Chemical compound [O-]N=O IOVCWXUNBOPUCH-UHFFFAOYSA-M 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- 238000009472 formulation Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- MEFBJEMVZONFCJ-UHFFFAOYSA-N molybdate Chemical compound [O-][Mo]([O-])(=O)=O MEFBJEMVZONFCJ-UHFFFAOYSA-N 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 229910052719 titanium Inorganic materials 0.000 description 2
- 229910001018 Cast iron Inorganic materials 0.000 description 1
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- 241000233866 Fungi Species 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 229910001030 Iron–nickel alloy Inorganic materials 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- 238000002479 acid--base titration Methods 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- XKMRRTOUMJRJIA-UHFFFAOYSA-N ammonia nh3 Chemical compound N.N XKMRRTOUMJRJIA-UHFFFAOYSA-N 0.000 description 1
- 230000001580 bacterial effect Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 239000011651 chromium Substances 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000009795 derivation Methods 0.000 description 1
- 238000000840 electrochemical analysis Methods 0.000 description 1
- 238000012851 eutrophication Methods 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
- 231100000171 higher toxicity Toxicity 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 230000000670 limiting effect Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000010687 lubricating oil Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 229910001000 nickel titanium Inorganic materials 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 231100000252 nontoxic Toxicity 0.000 description 1
- 230000003000 nontoxic effect Effects 0.000 description 1
- 230000000737 periodic effect Effects 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 239000003755 preservative agent Substances 0.000 description 1
- 230000002335 preservative effect Effects 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 239000013535 sea water Substances 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 239000013589 supplement Substances 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- 239000003643 water by type Substances 0.000 description 1
Images
Classifications
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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
- C02F1/66—Treatment of water, waste water, or sewage by neutralisation; pH adjustment
-
- 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
- C02F1/20—Treatment of water, waste water, or sewage by degassing, i.e. liberation of dissolved gases
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F7/00—Aeration of stretches of water
-
- 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
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2209/00—Controlling or monitoring parameters in water treatment
- C02F2209/06—Controlling or monitoring parameters in water treatment pH
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2209/00—Controlling or monitoring parameters in water treatment
- C02F2209/22—O2
-
- 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
- C02F2303/22—Eliminating or preventing deposits, scale removal, scale prevention
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Hydrology & Water Resources (AREA)
- Engineering & Computer Science (AREA)
- Environmental & Geological Engineering (AREA)
- Water Supply & Treatment (AREA)
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Preventing Corrosion Or Incrustation Of Metals (AREA)
Abstract
The invention particularly relates to a chemical treatment method for corrosion prevention of a metal material of a cooling water system of nuclear power plant equipment, which comprises the following steps: adding medicines into a cooling water system of the nuclear power plant equipment, wherein the medicines comprise morpholine and hydrazine, regulating the pH value of the cooling water system of the nuclear power plant equipment through the morpholine, and controlling dissolved oxygen in the cooling water system of the nuclear power plant equipment through the hydrazine. The method can avoid the problems of unqualified water quality and corrosion caused by the leakage of non-volatile high-concentration corrosion inhibitor medicines into other systems, and can simplify or eliminate the problems of the existing corrosion inhibitors in the aspects of microbial corrosion, system water discharge treatment and the like.
Description
Technical Field
The invention relates to the technical field of chemical water treatment corrosion prevention, in particular to a chemical treatment method for corrosion prevention of a metal material of a cooling water system of equipment in a nuclear power plant.
Background
In a nuclear power plant, an equipment cooling water system is mainly used for heat energy derivation of a shutdown cooling heat exchanger, a moderator heat exchanger, a spent pool heat exchanger, a main pump shaft seal cooler, an emergency refrigerator and an air compressor of a nuclear island, and a lubricating oil cooler, a stator water heat exchanger, a rotor hydrogen cooling heat exchanger and an excitation cooler of a conventional island so as to ensure normal economic operation of a nuclear power unit.
The pipelines of the systems are mainly made of carbon steel, the heat exchangers are mainly made of copper, stainless steel, nickel alloy, cast iron, aluminum, titanium and the like, and the water is desalted water. The equipment cooling water leakage caused by the scaling and corrosion perforation of the pipeline and the heat exchanger affects the safety of the system, particularly equipment related to the safety of a nuclear power plant, such as a shutdown cooling heat exchanger, a main pump shaft seal heat exchanger and the like. Therefore, the corrosion prevention of equipment cooling water systems is of great importance to nuclear power plants. In order to slow down the corrosion of related systems and improve the safety of the systems, chemicals are added into the systems to realize the corrosion control of equipment cooling water system materials.
At present, the chemical treatment method of corrosion inhibition chemicals by cooling water of domestic closed equipment mainly comprises the following steps: chromate formula, nitrite formula, silicate formula, molybdate formula, phosphate formula and the like, and although the older chromate formula has good corrosion inhibition effect and low price, the chromate formula has higher toxicity and pollutes the environment, and is banned at home and abroad; the classic nitrite formula is limited in use due to its high preservative concentration and emission, and the promotion of the growth of certain fungi; the silicate formula has long time for the generated protective film, is easy to damage, is easy to generate silicate scale due to poor control and is difficult to remove; the formula of the molybdate is nontoxic, does not pollute the environment, and has high cost; the phosphate formulation causes eutrophication of local waters due to phosphorus discharge, and is decreasing day by day.
The corrosion inhibitor formula is a formula containing a large amount of mineral substances, although the corrosion prevention effect can meet the requirements of national standard GB 50050-2017, if the corrosion inhibitor leaks into other systems with high water quality requirements, secondary problems such as unqualified water quality or corrosion of other systems can be caused; meanwhile, the use concentration of the medicines with the formulas is generally high, the system water discharge can not meet the requirements of national wastewater discharge standard GB8978-1996 on total chromium, phosphate, ammonia nitrogen, pH value and the like, and the subsequent waste liquid treatment cost is high; in addition, systems using the above corrosion inhibiting formulations have been found to suffer from bacterial and microbial corrosion.
Disclosure of Invention
Therefore, it is necessary to provide a chemical treatment method for corrosion prevention of metal materials in a cooling water system of nuclear power plant equipment, which can avoid the problems of unqualified water quality and corrosion caused by the leakage of a non-volatile high-concentration corrosion inhibitor into other systems, and can simplify or eliminate the problems of microbial corrosion, system water discharge treatment and the like of the conventional corrosion inhibitor, aiming at the problems of the conventional cooling water system of nuclear power plant equipment.
In order to achieve the above purpose, the invention provides the following technical scheme:
a chemical treatment method for corrosion prevention of metal materials of a cooling water system of nuclear power plant equipment comprises the following steps: drugs are added into a cooling water system of the nuclear power plant equipment, the drugs comprise morpholine and hydrazine, the pH value of the cooling water system of the nuclear power plant equipment is adjusted through the morpholine, and dissolved oxygen in the cooling water system of the nuclear power plant equipment is controlled through the hydrazine, so that the aim of preventing metal materials of the cooling water system of the nuclear power plant equipment from being corroded is fulfilled.
Furthermore, the concentration of the morpholine is 10-100mg/kg, the concentration of the diamine is 0.5-30mg/kg, so that the pH value of a cooling water system of the nuclear power plant equipment is 9.2-9.8, and the concentration of dissolved oxygen is less than 50 mu g/kg.
Further, morpholine is a commercial industrial grade product, C 4 H 9 NO content is more than or equal to 98wt%, boiling range is 127-130 ℃, and density rho 20 At 0.999-1.002g/cm 3 The chroma is less than or equal to 15Hazen units (platinum-cobalt color number), the appearance is clear and has no suspended matters, the alcohol dissolution test is qualified, the water content is less than or equal to 0.3wt percent, the nonvolatile matter is less than or equal to 0.01wt percent, the iron content (Fe) is less than or equal to 20mg/kg, the sodium content (Na) is less than or equal to 10mg/kg, and the chloride content (in terms of Cl) - Meter) is less than or equal to 10mgkg, sulfate content (in SO) 4 2- Calculated by Pb, is less than or equal to 10mg/kg, and the content of heavy metal (calculated by Pb) is less than or equal to 5mg/kg.
Further, the hydrazine is a commercial industrial grade product, hydrazine hydrate (N) 2 H 4 ·H 2 O) content of more than or equal to 35wt%, ignition residue of less than or equal to 0.002wt%, pH value (3% aqueous solution) of 9.9, and chloride content (in terms of Cl) - Calculated by weight percent is less than or equal to 0.001 percent, and the content of fluoride (calculated as F) - Calculated as SO) content of less than or equal to 0.001wt%, sulfate content (calculated as SO) 4 2- Calculated by Pb, is less than or equal to 0.001wt percent, the sodium content (Na) is less than or equal to 0.001wt percent, the iron content (Fe) is less than or equal to 0.001wt percent, and the heavy metal content (calculated by Pb) is less than or equal to 0.0005wt percent.
Further, the medicine is added to the nuclear power plant equipment cooling water system in one of the following two ways:
the first method comprises the following steps: calculating the weight of required morpholine and/or hydrazine hydrate according to the water charge amount of a cooling water system of the nuclear power plant equipment and the target concentration of dosing, and then adding the morpholine and/or hydrazine hydrate into the cooling water system of the nuclear power plant equipment through a dosing box;
the second method comprises the following steps: calculating the dosing flow of the metering pump and the dosing concentration of the added drugs according to the leakage rate and the dosing target concentration of the cooling water system of the nuclear power plant equipment, and then continuously adding the dosing pump and the dosing tank into the cooling water system of the nuclear power plant equipment.
Further, when the equipment needs to be drained during maintenance, morpholine and hydrazine are not added or the output force of a metering pump is reduced for a period of time before the maintenance time point of the equipment needing to be drained, so that the concentration of morpholine and hydrazine in the system water is maintained to be slightly higher than the lower limit of an index for operation, a small amount of strong acid is added into the system to enable the system water to reach the standard requirement of national comprehensive wastewater discharge, or the system water is drained into an open container and placed for a period of time or air is blown in, so that the system water reaches the national standard discharge requirement.
The invention has the beneficial technical effects that:
according to the chemical treatment method for preventing corrosion of the metal material of the cooling water system of the nuclear power plant equipment, the corrosion prevention effect completely meets the requirements that the steel corrosion rate is less than 0.075mm/a and the copper corrosion rate is less than 0.005mm/a, which are required in the national standard GB 50050-2017 industrial circulating cooling water treatment design specification, microbial corrosion does not occur, and the discharged water can meet the national standard discharge requirement through simple treatment.
Drawings
FIG. 1 is a schematic diagram showing the relationship between the concentration of morpholine and the pH value in a cooling water system of a nuclear power plant according to example 1;
FIG. 2 is a schematic diagram of a nuclear power plant equipment cooling water system configuration.
In the figure, 1, a high level water tank; 2. a metering pump; 3. a circulation pump; 4. a user heat exchanger; 5. a hot-trap heat exchanger; 6. a dosing box; 7. a medicine feeding pump.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and examples.
Example 1
The invention provides a chemical treatment method for corrosion prevention of a metal material of a cooling water system of nuclear power plant equipment, which is applied to corrosion prevention of the metal material of the cooling water system of certain power plant equipment and comprises the following steps: drugs are added into a cooling water system of the nuclear power plant equipment, the drugs comprise morpholine and hydrazine, the pH value of the cooling water system of the nuclear power plant equipment is adjusted through the morpholine, and dissolved oxygen in the cooling water system of the nuclear power plant equipment is controlled through the hydrazine, so that the aim of preventing metal materials of the cooling water system of the nuclear power plant equipment from being corroded is fulfilled.
The working principle is as follows: as the water supplement of the nuclear power plant equipment cooling water system is desalted water with extremely low impurity content, the materials of the equipment pipeline comprise carbon steel, stainless steel, copper, nickel alloy, titanium and the like, wherein the corrosion resistance effect of the stainless steel, the iron-nickel alloy and the titanium in the medium based on the desalted water is generally excellent and is not a main material generally, so that the formula mainly focuses on the corrosion resistance of the carbon steel and the copper. The chemical treatment method for preventing corrosion of the metal material of the cooling water system of the nuclear power plant equipment uses morpholine with excellent corrosion inhibition effect on carbon steel and copper, and the deoxidization effect of diamine, so that the purpose of preventing metal corrosion is achieved, and the phenomenon of microbial corrosion can not occur. Morpholine and hydrazine are volatile substances, and the two substances can not cause unqualified water quality and even corrosion problems to other systems if leaking into other systems.
Furthermore, the concentration of the morpholine is 10-100mg/kg, the concentration of the diamine is 0.5-30mg/kg, so that the pH value of a cooling water system of the nuclear power plant equipment is 9.2-9.8, and the concentration of dissolved oxygen is less than 50 mu g/kg.
Further, morpholine is a commercial industrial grade product, C 4 H 9 NO content is more than or equal to 98wt%, boiling range is 127-130 ℃, and density rho 20 At 0.999-1.002g/cm 3 The chroma is less than or equal to 15Hazen units (platinum-cobalt color number), the appearance is clear and has no suspended matters, the alcohol dissolution test is qualified, the water content is less than or equal to 0.3wt percent, the nonvolatile matter is less than or equal to 0.01wt percent, the iron content (Fe) is less than or equal to 20mg/kg, the sodium content (Na) is less than or equal to 10mg/kg, and the chloride content (in terms of Cl) - Calculated) is less than or equal to 10mg/kg, sulfate content (in SO) 4 2- Calculated by Pb, is less than or equal to 10mg/kg, and the content of heavy metal (calculated by Pb) is less than or equal to 5mg/kg.
Further, the hydrazine is a commercial industrial grade product, hydrazine hydrate (N) 2 H 4 ·H 2 O) content of more than or equal to 35wt%, ignition residue of less than or equal to 0.002wt%, pH value (3% aqueous solution) of 9.9, and chloride content (in terms of Cl) - Calculated by weight percent is less than or equal to 0.001 percent, and the content of fluoride (calculated as F) - Calculated as SO) content of less than or equal to 0.001wt%, sulfate content (calculated as SO) 4 2- Calculated by Pb, is less than or equal to 0.001wt percent, the sodium content (Na) is less than or equal to 0.001wt percent, the iron content (Fe) is less than or equal to 0.001wt percent, and the heavy metal content (calculated by Pb) is less than or equal to 0.0005wt percent.
Referring to fig. 2, the cooling water system of the nuclear power plant equipment comprises a circulating water pump, a user heat exchanger, a hot well heat exchanger, a high-level water tank, a dosing facility and related metal pipelines. The circulating water pump delivers the cooling water to each user heat exchanger, the user medium on the shell side of the heat exchanger is cooled, the cooling water is heated, and the heated cooling water returns to the inlet of the circulating water pump after being cooled by seawater or river water through the heat trap heat exchanger. System pressure is maintained by the head tank, and charge loss due to small leaks is maintained by replenishing the demineralized water.
Morpholine and hydrazine hydrate are added by a dosing system indicated by the dashed line in figure 2 in order to maintain the system water at morpholine concentrations of 10-100mg/kg and hydrazine concentrations of 0.5-30 mg/kg. In fig. 2, 2 dosing modes are given, and regardless of the dosing mode, the dosing quantity and the addition are calculated according to the upper limit of indexes when the system is filled with the oxygen-containing demineralized water for the first time.
The first method comprises the following steps: calculating the required weight of morpholine and/or hydrazine through the water charge amount and the dosing target concentration of a nuclear power plant equipment cooling water system, and then adding the morpholine and/or hydrazine into the nuclear power plant equipment cooling water system through a dosing box, wherein the dosing target concentration needs to be increased to be close to the upper limit of a morpholine index of 100mg/kg or the upper limit of a hydrazine index of 30mg/kg, and then adding the medicament again after the dosing target concentration is reduced to be close to the lower limit of the hydrazine index of 0.5mg/kg after a period of operation;
the second method comprises the following steps: the dosing flow of the metering pump and the dosing concentration of the added drugs are calculated according to the leakage rate and the dosing target concentration of the nuclear power plant equipment cooling water system, and then the dosing pump and the dosing tank are continuously added into the nuclear power plant equipment cooling water system, and the concentration of the diamine in the method can be maintained to be higher than the lower limit of the index in the normal operation of the system, namely, the concentration of the diamine is maintained to be 0.5-5mg/kg. The chemical adding mode can ensure that only a small amount of strong acid is added into the system during the discharge treatment, and the pH value discharge requirement required by the national standard can be met.
In order to control the concentration of the corrosion inhibitor formula within a required specified range, periodic detection is required for corrosion inhibitors such as morpholine, hydrazine, parameters of pH value, dissolved oxygen, iron, copper and the like of the control effect of the morpholine and the hydrazine. The detection frequency of morpholine, diamine, pH value and dissolved oxygen is once a week, and when the detection frequency exceeds the index, the medicine needs to be added in time; the detection of iron and copper reflecting the corrosion inhibition effect requires monthly usage.
When the chemical treatment method for corrosion prevention of the metal material of the cooling water system of the nuclear power plant equipment is used, only the upper limit of the index of the discharge requirement, which is slightly lower than the national standard GB8978-1996 integrated wastewater discharge standard, of the pH value is 9.0 when the system water is directly discharged. Further, when the equipment needs to be drained during maintenance, morpholine and hydrazine are not added or the continuous force of a metering pump is reduced for a period of time before the maintenance time point of the equipment needing to be drained, so that the concentration of morpholine and hydrazine in the system water is maintained to be slightly higher than the lower limit of an index (for example, the concentration of hydrazine in the system water is enabled to be operated at 0.5-2 mg/kg), a small amount of strong acid is added into the system, the acid addition amount can be determined through acid-base titration or calculation, generally, hundreds of milliliters of sulfuric acid or nitric acid are added into 50 cubic meters of wastewater, so that the system water meets the national comprehensive wastewater discharge standard requirements, or the system water is placed in an open container for a period of time or air is blown, so that the system water meets the national standard discharge requirements.
By using a representative material, namely carbon steel A106B and cupronickel B10 containing 10% of nickel, which have poor corrosion resistance in an equipment cooling water system, static and dynamic hanging test, corrosion behavior evaluation and oxide film evaluation are carried out according to national standards such as GB/T18175-2000 ' determination of corrosion inhibition performance of water treatment agents ' rotating hanging method ' and GB/T24196-2009 ' corrosion electrochemical test method for metals and alloys ' in two water quality environments of ' 50ppm morpholine +5ppm hydrazine ' and ' 100ppm morpholine +5ppm hydrazine ', and the results are shown in Table 1.
TABLE 1 Corrosion Rate of carbon Steel and cupronickel at different "morpholine and diamine" concentrations
Test results show that the anticorrosive effect completely meets the requirements of the national standard GB 50050-2017 design Specification for industrial circulating cooling water treatment that the corrosion rate of steel is less than 0.075mm/a and the corrosion rate of copper is less than 0.005mm/a, and the observed corrosion behavior and the formed oxide film are normal.
The chemical treatment method for corrosion prevention of the metal material of the cooling water system of the nuclear power plant equipment is applied to corrosion prevention of the metal material of the cooling water system of the power plant equipment, the iron content in water representing the corrosion degree of a system is maintained below 50 mu g/kg, the copper content is below 20 mu g/kg, no microbial corrosion phenomenon is found, a small amount of sulfuric acid is added into system discharge water before discharge during maintenance for simple treatment, and the discharge water quality meets the discharge requirement specified by the national standard GB 8978-1996.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is specific and detailed, but not to be understood as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (6)
1. A chemical treatment method for corrosion prevention of metal materials of a cooling water system of nuclear power plant equipment is characterized by comprising the following steps: adding medicines into a cooling water system of the nuclear power plant equipment, wherein the medicines comprise morpholine and hydrazine, regulating the pH value of the cooling water system of the nuclear power plant equipment through the morpholine, and controlling dissolved oxygen in the cooling water system of the nuclear power plant equipment through the hydrazine.
2. The chemical treatment method according to claim 1, wherein the concentration of morpholine is 10-100mg/kg and the concentration of diamine is 0.5-30mg/kg, so that the pH value in a cooling water system of nuclear power plant equipment is 9.2-9.8, and the concentration of dissolved oxygen is less than 50 μ g/kg.
3. A chemical treatment process according to claim 1, wherein the morpholine is a commercial technical grade product, C 4 H 9 NO content not less than 98wt%, boiling range 127-130 deg.c, density rho 20 At 0.999-1.002g/cm 3 The chroma is less than or equal to 15Hazen units (platinum-cobalt color number), the appearance is clear and has no suspended matters, the alcohol dissolution test is qualified, the water content is less than or equal to 0.3wt percent, the nonvolatile matter is less than or equal to 0.01wt percent, the iron content (Fe) is less than or equal to 20mg/kg, the sodium content (Na) is less than or equal to 10mg/kg, and the chloride content (in terms of Cl) - Calculated) is less than or equal to 10mg/kg, sulfate content (in SO) 4 2- Calculated by Pb, is less than or equal to 10mg/kg, and the content of heavy metal (calculated by Pb) is less than or equal to 5mg/kg.
4. A chemical treatment process according to claim 1, wherein said hydrazine is a commercial technical grade hydrazine hydrate (N) 2 H 4 ·H 2 O) content of not less than 35wt%, ignition residue of not more than 0.002wt%, pH value (3% aqueous solution) of 9.9, and chloride content (in order ofCl - Calculated by weight percent is less than or equal to 0.001 percent, and the content of fluoride (calculated as F) - Calculated as SO) content of less than or equal to 0.001wt%, sulfate content (calculated as SO) 4 2- Calculated) is less than or equal to 0.001wt percent, the sodium content (Na) is less than or equal to 0.001wt percent, the iron content (Fe) is less than or equal to 0.001wt percent, and the heavy metal content (calculated as Pb) is less than or equal to 0.0005wt percent.
5. The chemical treatment method according to claim 1, wherein the chemical is added to the cooling water system of the nuclear power plant equipment by one of:
the first method comprises the following steps: calculating the weight of required morpholine and/or hydrazine hydrate according to the water charge amount of a cooling water system of the nuclear power plant equipment and the target concentration of dosing, and then adding the morpholine and/or hydrazine hydrate into the cooling water system of the nuclear power plant equipment through a dosing box;
the second method comprises the following steps: the chemical adding flow of the metering pump and the added chemical preparation concentration are calculated according to the leakage rate and the chemical adding target concentration of the nuclear power plant equipment cooling water system, and then the chemical adding flow and the added chemical preparation concentration are continuously added into the nuclear power plant equipment cooling water system through the metering pump and the chemical adding box.
6. A chemical treatment process according to claim 1, wherein when the system water is required to be drained for equipment maintenance, morpholine and hydrazine are not added or the continuous addition of the output of the metering pump is reduced for a period of time before the maintenance time point of the equipment requiring drainage, and strong acid is added to the system to make the system water meet the national integrated wastewater discharge standard, or the system water is placed in an open container for a period of time or air is blown to make the system water meet the national standard discharge requirement.
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB884932A (en) * | 1957-05-14 | 1961-12-20 | Stephen Robert Mercer Ellis | Improvements in or relating to the prevention of corrosion of metals in contact with oxygen-containing water |
| KR20170095596A (en) * | 2016-02-15 | 2017-08-23 | 전남대학교산학협력단 | Water treatment composition containing carbohydrazide for power plant boiler system |
| CN110713220A (en) * | 2019-11-06 | 2020-01-21 | 西安热工研究院有限公司 | Dosing system and method for oxygen scavenger hydrazine in secondary loop system of high-temperature gas cooled reactor nuclear power plant |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB884932A (en) * | 1957-05-14 | 1961-12-20 | Stephen Robert Mercer Ellis | Improvements in or relating to the prevention of corrosion of metals in contact with oxygen-containing water |
| KR20170095596A (en) * | 2016-02-15 | 2017-08-23 | 전남대학교산학협력단 | Water treatment composition containing carbohydrazide for power plant boiler system |
| CN110713220A (en) * | 2019-11-06 | 2020-01-21 | 西安热工研究院有限公司 | Dosing system and method for oxygen scavenger hydrazine in secondary loop system of high-temperature gas cooled reactor nuclear power plant |
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