CN1172025C - Corrosion inhibiting method for cooling water system of production equipment in shutdown period - Google Patents
Corrosion inhibiting method for cooling water system of production equipment in shutdown period Download PDFInfo
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- CN1172025C CN1172025C CNB021005966A CN02100596A CN1172025C CN 1172025 C CN1172025 C CN 1172025C CN B021005966 A CNB021005966 A CN B021005966A CN 02100596 A CN02100596 A CN 02100596A CN 1172025 C CN1172025 C CN 1172025C
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Abstract
The present invention relates to a corrosion inhibiting method for a cooling water system of production apparatuses in shutdown periods, which comprises the following steps: 1) water coolers and water pipelines in the cooling water system of circulation water are washed and prefilmed in a work state before the apparatuses enter the shutdown period; 2) the cooling water in the system is drained clearly and dried by blowing, and hygroscopic agents are put in the system; the relative air humidity of the system in a seal state is controlled below 60 %; 3) vapor phase inhibitors are added according to the dosage of 0.5 to 2.5 kg/m3 of the volume of the system; after the vapor phase inhibitors are added, an opening for adding the vapor phase inhibitor is instantly closed so that the system is in a seal state. The method of the present invention has the advantages of good and reliable corrosion inhibition effect, convenient operation and low operation cost. After treatment according to the method, the system can keep the effect on inhibiting the corrosion of carbon steel test pieces to reach D8 level.
Description
Technical field
The invention belongs to metal material surface anticorrosion technique field, specifically, relate to and suppress the recirculating cooling water system corroding method during production equipment is stopped transport.
Technical background
Along with the establishment and the development of socialist market economy system, market discipline is to the production and the important effect of development play more and more of petrochemical industry, and enterprise must make the corresponding production program according to the price change of market starting material, product.When market is favourable to producing, production equipment full load or overload operation; Market is to producing when unfavorable, production equipment load shedding even out of service.Practice finds that the water cooler and the corrosion of water-transmission line during stopping transport of cooling water system is serious more than normal operation period, particularly the metal equipment corrosion under the incrustation scale, in the wet environment is even more serious, cause the perforation of equipment and pipeline, shortened their work-ing life greatly.
The traditional protection method that suppresses metal equipment corrosion during device is stopped transport mainly contains " wet method " and " dry method " two kinds." wet method " protection is to fill with the liquid protective medium (in most cases being water medium) that adds a certain amount of inhibiter or oxygen scavenger in cooling water system.The protection effect of device that this method is less to volume, sealing property is high or equipment is better, but big to volume, airtight performance difference or device that can not be airtight, and the protection effect is relatively poor, and erosion rate is still bigger, and expense is higher.The protection that reinject after the liquid medium emptying in the device nitrogen or air are carried out is called " dry method " protection.The expense of dry method protection is lower, but preservative effect is still undesirable, and particularly device has the position of residuary water, corrodes more serious.Big for volumetric ratio at present, the relatively poor petrochemical unit cooling water system of stopping property lacks effective, reliable, economic guard method.
Summary of the invention
The objective of the invention is to propose a cover and be applicable to the guard method that suppresses cooling water system equipment and pipeline corrosion during production equipment is stopped transport.The inventive method has overcome simple usefulness " wet method " the protection deficiency that effect is relatively poor, expense is higher; also overcome the problem of the underdeposit corrosion that often occurs with tradition " dry method " protection; have and suppress the advantage that metal equipment corrosion is effective, easy to operate, cost is low.
Suppress the circulating water system corroding method during production equipment provided by the invention is stopped transport, comprise following a few part:
1, the cleaning of cooling water system and pre-film.
Before device stops, the watercooler in the cooling water system and water-transmission line do not stopped and clean and pre-film, remove foundry loam, incrustation scale and the corrosion product of the equipment of being attached to and pipeline surface, at metallic surface formation layer protecting film.
Specifically, stopped preceding 24～150 hours at device, preferred 72～120 hours, add the recirculated cooling water commonly used chemical that do not stop, the concentration of clean-out system is 100～2500mg/L, and preferred 250～1500mg/L is controlled at 3～4 with mineral acid with the pH value of recirculated cooling water, operation is 6～30 hours continuously, preferred 12～24 hours.Water iron ion during the cleaning, calcium ion, turbidity isoconcentration will raise significantly, after the iron concentration of water to be cleaned, turbidity etc. reach maximum value, open the blowdown water valve to greatest extent and additional water valve is replaced, in the short as far as possible time, rinse water is displaced system.
Said clean-out system is a circulating water system clean-out system commonly used, is made up of acid, adhesive mud remover, inhibiter.Acid wherein can be sulfuric acid, nitric acid, thionamic acid, citric acid, EDTA and composition thereof.Adhesive mud remover wherein is dimethyl benzyl dodecyl chlorination ammonium, dimethyl benzyl dodecyl bromination ammonium, dimethyl benzyl tetradecyl ammonium chloride or other tensio-active agent, and the inhibiter of wherein stating can be thiocarbamide, hexamethylenetetramine, if fourth and composition thereof.
Clean and change water when system and finish, according to the pre-film of ordinary method, prefilming agent is a circulating water system prefilming agent commonly used, can be tripoly phosphate sodium STPP, Sodium hexametaphosphate 99, zinc chloride, zinc sulfate, PAPE etc.Concrete pre-film step is: add 20～250mg/L in the water sucking mouth, preferred 100～200mg/L prefilming agent was slowly adding 2～98% (v/v) industrial sulphuric acid away from the water sucking mouth again after 0.5～2.0 hour, and pH transfers to 5.5～6.0 with recirculated water.PH is lower than 5.5 if industrial sulphuric acid adds the back, then uses industrial Na
2CO
3Return accent.Total phosphorus and the calcium of analyzing a recirculated water at interval in 2～8 hours are hard, if total phosphorus is lower than 90mg/L, should add an amount of Sodium hexametaphosphate 99 and ZnSO in proportion
47H
2O adds Sodium hexametaphosphate 99 certainly and picks up counting, and moves 24～72 hours continuously.
2, dehumidifying in the cooling water system.
Device is through cleaning and after pre-film stops, the intrasystem water coolant of emptying, and air blast dries up, and places moisture adsorbent after 24～72 hours, and the relative air humidity of Controlling System under air-tight state is below 60%.Moisture adsorbent is preferably in the system many places and evenly places, to reach moisture sorption effect preferably.
Said moisture adsorbent can be calcium oxide, silica gel, Calcium Chloride Powder Anhydrous, molecular sieve etc.
3, in system, inject vapour-phase inhibitor.
Relative humidity less than 60% cooling water system in, according to system volume 0.5～2.5kg/m
3Consumption add vapour-phase inhibitor equably along equipment pipe, interchanger etc., after adding, close the inlet that adds of vapour-phase inhibitor immediately, make system be in closed state.
Said vapour-phase inhibitor can be chromic acid dicyclohexyl amine, phenylformic acid dicyclohexyl amine, dicyclohexyl amine nitrite, cyclohexylamine carbonate or their mixture etc., and above-mentioned inhibiter is the commercial goods.
Suppress during production equipment provided by the invention is stopped transport the recirculating cooling water system corroding method have good, suppress corrosive effect reliably, after this method processing, system can keep suppressing carbon steel test piece corrosive effect D8 level, and easy to operate, and working cost is low.
Embodiment
Embodiment 1
Step 1: the cooling water system cleaning of not stopping
Stopped preceding 96 hours at device, add the mixture of clean-out system sodium polyacrylate, ethylene diamine tetra methylene phosphonic acid and citric acid.The concentration of clean-out system is 1200mg/L, and adding sulfuric acid, hydrochloric acid or nitric acid are controlled at 4 with the pH value of recirculated cooling water, move 24 hours continuously.Open the blowdown water valve and additional water valve is replaced, at short notice rinse water is displaced system.
Step 2: to the pre-film of cooling water system
Clean and change water when system and finish, add the 120mg/L Sodium hexametaphosphate 99 in the water sucking mouth, add 80mg/L ZnSO after 0.5 hour
47H
2O is transferring to 6.0 away from slow 1% (v/v) industrial sulphuric acid that adds in water sucking mouth with recirculated water pH after 0.5 hour again.Total phosphorus and the calcium of analyzing a recirculated water at interval in 8 hours are hard, add Sodium hexametaphosphate 99 certainly and pick up counting, and move 48 hours continuously.
Step 3: cooling water system draining
Pre-film finishes, and stops water circulating pump, opens wash water valve to greatest extent, removal system ponding in the short as far as possible time.To the U type pipe ponding that can not drain from water port, blind hole and the water discharge valve of opening this place discharge water.
After intrasystem water base the emptying, with blast volume＞125m
3The gas blower of/min blasts air in system, continuous blast 48 hours.
Step 4: cooling water system dehumidifying
After the cooling water system continuous blast 48 hours, turn off the blast, open manhole on the Trunk Line, place chemical hygroscopic agent calcium oxide or silica gel or Calcium Chloride Powder Anhydrous etc. every about 100 meters, after the chemical hygroscopic agent was put well, all blow-off valves of closure systems made system be in closed state.
The chemical hygroscopic agent can reduce the relative humidity of system and maintain below 60%, and the aerial erosion rate of metal is significantly reduced.
Step 5: adopt vapour-phase inhibitor to protect to cooling water system
Relative humidity less than 60% cooling water system in, according to system volume 1.5kg/m
3Amount add the mixture of vapour-phase inhibitor chromic acid dicyclohexyl amine and dicyclohexyl amine nitrite equably along equipment pipe, interchanger etc., after vapour-phase inhibitor adds, close the inlet that adds of vapour-phase inhibitor immediately, make system be in closed state.In this case, system can keep suppressing carbon steel test piece corrosive effect D8 level above 1 year.
Embodiment 2
Clean-out system is the mixture of vinylformic acid and AMPS multipolymer, amido three methene phosphonic acids and citric acid, and vapour-phase inhibitor is phenylformic acid dicyclohexyl amine and cyclohexylamine carbonate mixture, and all the other are with embodiment 1.
Embodiment 3
Clean-out system is the mixture of dimethyl benzyl dodecyl chlorination ammonium and citric acid, and vapour-phase inhibitor is dicyclohexyl amine nitrite and cyclohexylamine carbonate mixture, and all the other are with embodiment 1.
Claims (7)
1. suppress the cooling water system corroding method during a production equipment is stopped transport, may further comprise the steps:
1) before device stops, the watercooler in the circulation cooling water system and water-transmission line do not stopped and clean and film in advance;
2) the intrasystem water coolant of emptying, air blast dry up the back and place moisture adsorbent, and the relative air humidity of Controlling System under air-tight state is below 60%;
3) according to system volume 0.5～2.5kg/m
3Consumption add vapour-phase inhibitor, after adding, close the inlet that adds of vapour-phase inhibitor immediately, make system be in air-tight state.
2. in accordance with the method for claim 1, it is characterized in that, said cleaning is to stop preceding 24～150 hours at device, add the recirculated cooling water chemical that do not stop, the concentration of clean-out system is 100～2500mg/L, with mineral acid the pH value of recirculated cooling water is controlled at 3～4, moves 6～30 hours continuously.
3. in accordance with the method for claim 2, it is characterized in that, said clean-out system is made up of acid, adhesive mud remover, inhibiter, acid wherein is selected from sulfuric acid, nitric acid, thionamic acid, citric acid and EDTA, adhesive mud remover wherein is dimethyl benzyl dodecyl chlorination ammonium, dimethyl benzyl dodecyl bromination ammonium, dimethyl benzyl tetradecyl ammonium chloride, and inhibiter wherein is thiocarbamide, hexamethylenetetramine or if fourth.
4. in accordance with the method for claim 1, it is characterized in that, said prefilming method is: add 20～120mg/L prefilming agent in the water sucking mouth, after 0.5～2.0 hour, adding 2～98% industrial sulphuric acids again away from the water sucking mouth, pH transfers to 5.5～6.0 with recirculated water, total phosphorus and the calcium of analyzing a recirculated water at interval in 2～8 hours are hard, if total phosphorus is lower than 90mg/L, should add an amount of Sodium hexametaphosphate 99 and ZnSO in proportion
47H
2O adds Sodium hexametaphosphate 99 certainly and picks up counting, and moves 24～72 hours continuously.
5. in accordance with the method for claim 1, it is characterized in that said prefilming agent is selected from tripoly phosphate sodium STPP, Sodium hexametaphosphate 99, zinc chloride, zinc sulfate and PAPE.
6. in accordance with the method for claim 1, it is characterized in that said moisture adsorbent is selected from calcium oxide, silica gel, Calcium Chloride Powder Anhydrous and molecular sieve.
7. in accordance with the method for claim 1, it is characterized in that said vapour-phase inhibitor is selected from chromic acid dicyclohexyl amine, phenylformic acid dicyclohexyl amine, dicyclohexyl amine nitrite, cyclohexylamine carbonate and their mixture.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB021005966A CN1172025C (en) | 2002-02-07 | 2002-02-07 | Corrosion inhibiting method for cooling water system of production equipment in shutdown period |
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| Application Number | Priority Date | Filing Date | Title |
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| CNB021005966A CN1172025C (en) | 2002-02-07 | 2002-02-07 | Corrosion inhibiting method for cooling water system of production equipment in shutdown period |
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| Publication Number | Publication Date |
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| CN1436740A CN1436740A (en) | 2003-08-20 |
| CN1172025C true CN1172025C (en) | 2004-10-20 |
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| CNB021005966A Expired - Lifetime CN1172025C (en) | 2002-02-07 | 2002-02-07 | Corrosion inhibiting method for cooling water system of production equipment in shutdown period |
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Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101892489B (en) * | 2010-07-23 | 2012-11-07 | 广州唯普电力科技有限公司 | Cleaning agent for flue dust scale on surface of gas heat exchanger of gas desulfurization system and preparation method thereof |
| CN102051628B (en) * | 2010-10-14 | 2013-03-06 | 石家庄高新区华科环保科技有限公司 | Degradable environment-friendly dirt remover |
| CN102992509B (en) * | 2011-09-19 | 2014-05-07 | 中国石油化工股份有限公司 | Method for controlling pH of industrial cooling water circulation system |
| CN104911616B (en) * | 2014-03-12 | 2017-08-25 | 江苏核电有限公司 | A kind of nuclear power station freezes water supply system corrective maintenance maintaining method |
| CN110004447A (en) * | 2019-04-01 | 2019-07-12 | 国网浙江平湖市供电有限公司 | A kind of anti-corrosion method of electric system active service steel pipe pole inner wall |
| CN113005462B (en) * | 2019-12-20 | 2023-03-24 | 齐鲁工业大学 | Descaling and cleaning corrosion inhibitor and cleaning agent for 201 stainless steel |
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