阅读说明：本技术 汽轮机凝汽器水室内管板与管口胀接处的防腐防渗漏方法 (Anticorrosion and antiseep method for expansion joint of pipe plate and pipe orifice in water chamber of steam turbine condenser ) 是由 孙立运 郑祥兵 朱诚 王成华 范秀芳 杨乐德 刘志昌 李梦龙 于 2020-07-31 设计创作，主要内容包括：本发明汽轮机凝汽器水室内管板与管口胀接处的防腐防渗漏方法,所述方法包括步骤1,先将凝汽器水室内管板与管口胀接处的海水置换干净,再将它们干燥,最后对管口、管板和管板与管口胀接处进行打磨,使它们表面的金属本色全部露出,得到打磨后的管口和管板；步骤2,在打磨后的管板整个表面,以及打磨后的管板与打磨后的管口的胀接处依次均匀且平整地涂刷若干层防腐涂料,涂刷完成后在打磨后的管板整个表面形成第一防腐层；在打磨后的管口的整个管壁中均匀且平整地依次涂刷若干层防腐涂料,涂刷完成后在打磨后的管口中形成第二防腐层；步骤3,将第一防腐层和第二防腐层进行固化,完成汽轮机凝汽器水室内管板与管口胀接处的防腐防渗漏。(The invention relates to an anticorrosion and antiseep method for the expansion joint of an inner tube plate and a pipe orifice in a water chamber of a steam turbine condenser, which comprises the following steps of 1, firstly, completely replacing seawater at the expansion joint of the inner tube plate and the pipe orifice in the water chamber of the steam condenser, then drying the seawater, and finally, polishing the pipe orifice, the pipe plate and the expansion joint of the pipe plate and the pipe orifice to ensure that the natural metal colors on the surfaces of the pipe orifice, the pipe plate and the expansion joint of the pipe plate and the pipe orifice are completely exposed to; step 2, sequentially and evenly brushing a plurality of layers of anticorrosive coatings on the whole surface of the polished tube plate and the expansion joint of the polished tube plate and the polished tube orifice, and forming a first anticorrosive layer on the whole surface of the polished tube plate after finishing brushing; sequentially and evenly painting a plurality of layers of anticorrosive coatings in sequence on the whole pipe wall of the polished pipe orifice, and forming a second anticorrosive layer in the polished pipe orifice after painting; and 3, solidifying the first anticorrosive layer and the second anticorrosive layer to finish the corrosion prevention and leakage prevention of the expansion joint of the tube plate and the tube orifice in the water chamber of the steam turbine condenser.)

1. The method for preventing corrosion and leakage at the expanded joint of the pipe plate and the pipe orifice in the water chamber of the steam turbine condenser is characterized by comprising the following steps of:

step 1, firstly, replacing seawater at an expanded joint of a pipe plate and a pipe orifice in a water chamber of a steam turbine condenser, then drying the water chamber, the pipe orifice and the pipe plate, and finally polishing the pipe orifice, the pipe plate and the expanded joint of the pipe plate and the pipe orifice to ensure that the natural metal colors of the surfaces of the pipe orifice, the pipe plate and the expanded joint of the pipe plate and the pipe orifice are all exposed to respectively obtain a polished pipe orifice and a polished pipe plate;

step 2, sequentially and evenly brushing a plurality of layers of anticorrosive coatings on the whole surface of the polished tube plate and the expansion joint of the polished tube plate and the polished tube orifice, and forming a first anticorrosive layer on the whole surface of the polished tube plate after finishing brushing, wherein the total thickness of the coatings of the first anticorrosive layer is 0.4-0.6 mm;

uniformly and flatly painting a plurality of layers of anticorrosive paint in sequence on the whole pipe wall of the polished pipe orifice, wherein the depth of the anticorrosive paint painted into the pipe orifice is at least 20mm during painting, and a second anticorrosive layer is formed in the polished pipe orifice after painting is finished, and the total thickness of the coatings of the second anticorrosive layer is 0.2-0.4 mm;

and 3, solidifying the first anticorrosive layer and the second anticorrosive layer to finish the corrosion prevention and leakage prevention of the expansion joint of the tube plate and the tube orifice in the water chamber of the steam turbine condenser.

2. The method for preventing corrosion and leakage at the expanded joint of the tube plate and the pipe orifice in the water chamber of the steam turbine condenser according to claim 1, wherein step 1 uses fresh water to replace the seawater at the expanded joint of the tube plate and the pipe orifice.

3. The method for preventing corrosion and leakage at the expansion joint of the tube plate and the tube opening in the water chamber of the steam turbine condenser as claimed in claim 1, wherein step 1 is performed by purging the water chamber, the tube opening and the tube plate with compressed air to dry the water chamber, the tube opening and the tube plate;

and blowing clean dust after the pipe orifice, the pipe plate and the metal true color on the surface of the expansion joint of the pipe plate and the pipe orifice are completely exposed to obtain the polished pipe orifice and the polished pipe plate.

4. The method for preventing corrosion and leakage at the expanded joint of the pipe plate and the pipe orifice in the water chamber of the steam turbine condenser according to claim 1, wherein the type of the anticorrosive paint in the step 2 is KD-T4.

5. The method for preventing corrosion and leakage at the expanded joint of the tube plate and the pipe orifice in the water chamber of the steam turbine condenser according to claim 1, wherein three or four layers of anticorrosive paint are sequentially coated on the whole surface of the polished tube plate and the expanded joint of the polished tube plate and the polished pipe orifice in the step 2.

6. The method of claim 5, wherein three different colors of anticorrosive coatings are applied to the whole surface of the polished tube sheet and the expansion joint between the polished tube sheet and the polished tube orifice.

7. The method for preventing corrosion and leakage at the expanded joint of the tube plate and the tube opening in the water chamber of the steam turbine condenser according to claim 1, wherein two layers of anticorrosive coatings are sequentially coated on the whole tube wall of the polished tube opening in the step 2.

8. The method of claim 7, wherein the two layers of anticorrosive coatings are different in color.

9. The method for preventing corrosion and leakage at the expanded joint of the tube plate and the pipe orifice in the water chamber of the steam turbine condenser according to claim 1, wherein in the step 3, the first anticorrosive layer and the second anticorrosive layer are both cured at normal temperature, and the curing time is greater than or equal to 72 hours.

10. The method for preventing corrosion and leakage at the expanded joint of the tube plate and the tube opening in the water chamber of the steam turbine condenser according to claim 1, wherein in the step 3, the first anticorrosive layer and the second anticorrosive layer are cured by heating with a baking lamp for 24 hours or longer.

Technical Field

The invention relates to the technical field of corrosion prevention and leakage prevention, in particular to a corrosion prevention and leakage prevention method for an expansion joint of an inner pipe plate and a pipe orifice of a water chamber of a steam turbine condenser.

Background

In the thermodynamic cycle of a condensing steam turbine unit, a condenser plays the role of a cold source, and the condenser is mainly used for condensing the exhaust steam of a steam turbine into water and establishing and maintaining a certain vacuum degree at the exhaust steam port of the steam turbine.

After the unit is put into operation, a large amount of corrosion conditions are found at the expansion joint of the tube plate and the titanium tube orifice in the water chamber on the circulating water side of the condenser during the previous overhaul period, because seawater circulates on the circulating water side of the condenser, the seawater has high salt content and contains sulfides. In addition, a large amount of silt in seawater erodes the expansion joint of the pipe plate and the titanium pipe orifice, and the sand erosion, abrasion and the like are generated at the joint, so that the corrosion and leakage of a condenser and the small leakage of the pipe orifice are caused, the quality of the condensed water of the unit is influenced, and salt substances entering a thermodynamic system can be deposited on the surface of the steam turbine, and the safe, stable and economic operation of the unit is threatened finally. Along with the continuous improvement of unit parameters, the condenser seepage, leak to soda quality, the safety and stability operation of unit influence is bigger.

In order to prevent the corrosion of the expansion joint of the tube plate and the titanium tube opening in the water chamber on the circulating water side of the condenser and further ensure the quality of condensed water of a unit, increase the safe use period of the expansion joint of the tube plate and the titanium tube opening, an anti-corrosion and anti-leakage scheme for the condenser needs to be formulated according to the current situation of the condenser, but due to the washing of water sources such as seawater and the influence of negative pressure in the condenser, corrosion points and leakage points at the expansion joint of the tube plate and the titanium tube opening in the water chamber of the condenser can be further expanded, and due to the restriction of the properties of titanium materials of the tube plate and the titanium tube, the leakage and corrosion points cannot be blocked by using a repairing agent, so that the phenomenon that the titanium tube is poor in adhesive attachment capacity and easy to fall off exists, and the.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides an anticorrosion and antiseep method for the expansion joint of the tube plate and the pipe orifice in the water chamber of the steam turbine condenser, so that the adhesion capability of an anticorrosion coating is strong, the anticorrosion area is wider after the positions of the tube plate and the pipe orifice are treated, and the equipment is safer to use.

The invention is realized by the following technical scheme:

the method for preventing corrosion and leakage at the expanded joint of the pipe orifice and the inner pipe plate of the water chamber of the steam turbine condenser comprises the following steps:

step 1, firstly, replacing seawater at an expanded joint of a pipe plate and a pipe orifice in a water chamber of a steam turbine condenser, then drying the water chamber, the pipe orifice and the pipe plate, and finally polishing the pipe orifice, the pipe plate and the expanded joint of the pipe plate and the pipe orifice to ensure that the natural metal colors of the surfaces of the pipe orifice, the pipe plate and the expanded joint of the pipe plate and the pipe orifice are all exposed to respectively obtain a polished pipe orifice and a polished pipe plate;

step 2, sequentially and evenly brushing a plurality of layers of anticorrosive coatings on the whole surface of the polished tube plate and the expansion joint of the polished tube plate and the polished tube orifice, and forming a first anticorrosive layer on the whole surface of the polished tube plate after finishing brushing, wherein the total thickness of the coatings of the first anticorrosive layer is 0.4-0.6 mm;

uniformly and flatly painting a plurality of layers of anticorrosive paint in sequence on the whole pipe wall of the polished pipe orifice, wherein the depth of the anticorrosive paint painted into the pipe orifice is at least 20mm during painting, and a second anticorrosive layer is formed in the polished pipe orifice after painting is finished, and the total thickness of the coatings of the second anticorrosive layer is 0.2-0.4 mm;

and 3, solidifying the first anticorrosive layer and the second anticorrosive layer to finish the corrosion prevention and leakage prevention of the expansion joint of the tube plate and the tube orifice in the water chamber of the steam turbine condenser.

Preferably, step 1 uses fresh water to replace the seawater at the expansion joint of the tube plate and the tube orifice.

Preferably, in the step 1, compressed air is used for purging the water chamber, the pipe orifice and the pipe plate, so that the water chamber, the pipe orifice and the pipe plate are dried;

and blowing clean dust after the pipe orifice, the pipe plate and the metal true color on the surface of the expansion joint of the pipe plate and the pipe orifice are completely exposed to obtain the polished pipe orifice and the polished pipe plate.

Preferably, the model of the anticorrosive paint in the step 2 is KD-T4.

Preferably, in the step 2, three or four layers of anticorrosive paint are sequentially coated on the whole surface of the polished tube plate and the expansion joint of the polished tube plate and the polished tube orifice.

And further, brushing the three anti-corrosion coatings with different colors on the whole surface of the polished tube plate and the expansion joint of the polished tube plate and the polished tube opening for the first three layers.

Preferably, two layers of anticorrosive paint are sequentially coated in the whole pipe wall of the polished pipe orifice in the step 2.

Furthermore, the two layers of anticorrosive paint have different colors.

Preferably, in step 3, the first anticorrosive layer and the second anticorrosive layer are both cured at normal temperature, and the curing time is greater than or equal to 72 hours.

Preferably, in the step 3, the first anticorrosive layer and the second anticorrosive layer are cured by heating with a baking lamp, and the curing time is more than or equal to 24 hours.

Compared with the prior art, the invention has the following beneficial technical effects:

the invention relates to an anti-corrosion and anti-leakage method for the expanded joint of an inner tube plate and a tube orifice in a water chamber of a steam turbine condenser, which comprises the steps of firstly replacing seawater at the expanded joint of the inner tube plate and the tube orifice in the water chamber of the steam turbine condenser, then drying the water chamber, the tube orifice and the tube plate, and finally polishing the tube orifice, the tube plate and the expanded joint of the tube orifice and the tube orifice, so that the natural metal colors on the surfaces of the tube plate and the tube plate are all exposed, the anti-corrosion coating can be better and firmly attached to the surface of equipment and is not easy to fall off, then uniformly and flatly coating a plurality of layers of anti-corrosion coatings on the whole surface of the polished tube plate, the expanded joint of the polished tube plate and the polished tube orifice and the whole tube wall of the polished tube orifice, performing anti-corrosion treatment on the tube plate and the expanded joint of the tube orifice of the steam turbine to form a first anti-corrosion coating and a second anti-corrosion coating, wherein the total thickness of the coating of, the service cycle can be shortened, and the heat exchange effect of the condenser can be influenced if the thickness is too thick; the total thickness of the coating of the second anticorrosive coating is 0.2-0.4mm, so that the cleaning effect of rubber balls of titanium tubes in the condenser is not influenced, circulating water through flow is facilitated, heat exchange of the condenser is facilitated, anticorrosive coating is coated into the depth of the tube orifice by at least 20mm when being coated, and thus, sundries in seawater can not be scoured to the edge coating.

Furthermore, the KD-T4 type anticorrosive coating is adopted, and the components of the paint have chemicals such as hot water resistance, acid resistance, alkali resistance, salt mist, high chlorine radical and the like, so that the cured anticorrosive coating has the effects of wear resistance, impact resistance, hydrolysis resistance and ageing resistance, and has better anticorrosive and anti-seepage effects.

Furthermore, the anticorrosive paint is mixed into three different colors, and then the surface of the pretreated tube plate is coated with the first three layers, so that when the upper layer of the paint is coated, the lower layer of the paint is coated after drying and solidification, the lower layer of the paint can be more visually and uniformly coated, and the coating coverage is prevented from being insufficient.

Drawings

FIG. 1 is a diagram of rust formed by leakage at the expansion joint of a pipe plate and a titanium pipe orifice in a condenser.

FIG. 2 is a diagram of a tube plate and titanium tube mouth expansion joint after safe operation for one year by using KD-T4 type coating according to the scheme of the present invention.

Detailed Description

The present invention will now be described in further detail with reference to specific examples, which are intended to be illustrative, but not limiting, of the invention.

The tube plate in the steam turbine condenser water chamber is made of a titanium composite plate, and the material of the tube opening is titanium. Therefore, the invention discloses an anticorrosion and antiseep method for the expansion joint of a pipe plate and a pipe orifice in a water chamber at the circulating water side of a steam turbine condenser, which comprises the following steps;

step 1, fully cleaning the expansion joint of the pipe plate and the pipe orifice in the water chamber on the circulating water side of the condenser by using fresh water so as to replace the seawater completely.

And 2, performing forced ventilation by using compressed air, and blowing the titanium pipe orifice, the pipe plate and the water chamber to enable the titanium pipe orifice, the pipe plate and the water chamber to be in a dry state. A grinding tool electric grinding machine is matched with a soft hairbrush to grind the tube plate and the tube orifice, and the expansion joint of the tube plate and the tube orifice, so that an original anticorrosive coating, oxide skin, rust and the like are removed, and the surface is cleaned to facilitate the adhesion of paint. After the pipe orifice and the expansion joint of the pipe plate and the pipe orifice are polished to remove rust, oxide skin, rust and other dirt are thoroughly removed, and only slight traces are left, so that the original metal natural color is completely exposed.

And 3, blowing and cleaning the tube plate and the tube opening and dust at the expanded joint of the tube plate and the tube opening by using compressed air.

And 4, brushing the cleaned corrosion part by adopting the KD-T4 type anticorrosive paint.

The whole surface of the tube plate and the expansion joint of the polished tube plate and the polished tube opening are coated with four layers of KD-T4 type anticorrosive paint, the bottom surface is coated with a layer of white anticorrosive paint with the corresponding model of KD-T4-1, then a layer of red anticorrosive paint with the corresponding model of KD-T4-2 is coated to form an intermediate coating, the color of the coated anticorrosive paint is different, so that when the upper layer of paint is coated, the lower layer of paint is coated after drying and solidification, the lower layer of paint can be more intuitively coated uniformly, the coating coverage is prevented from being insufficient, finally two layers of gray are sequentially coated, the corresponding model of the anticorrosive paint is KD-T4-3, and the total thickness of the coating formed on the surface of the tube plate is 0.4-0.6mm because the fourth layer only plays an auxiliary role. After each layer is dried and solidified, the next layer is coated, and the coating is uniform and flat and has no sagging and falling phenomena. The coating is too thin, can be washed away by the debris in the circulating seawater of circulating among the circulating water hydroecium relatively fast, can reduce life cycle, and the coating is too thick, can influence condenser heat exchange effect.

Two layers of KD-T4 type anticorrosive paint are painted to the whole pipe wall, the bottom is painted with one layer of white paint and then painted with one layer of gray paint, which is the same as the last layer of pipe plate, so that the integrity of the part is maintained in appearance, the first layer is painted to cover the metal part, and the second layer is painted to cover the paint. The surface of the coating is uniform and flat, the adhesion is firm, the coating leakage phenomenon, no bubble, no pinhole and the like are avoided, and the next layer is coated after each layer is dried and solidified. The surface can not appear sagging phenomenon, and can not appear the protruding condition of coating high point and influence the glueballs and pass through, consequently the glueballs can wash away debris such as mud dirt on titanium pipe orifice surface through titanium pipe orifice, and glueballs card will prevent the circulating water circulation in the coating high point position, influences condenser heat transfer effect. If the coating of mouth of pipe too can make the coating thicker, can influence the rubber ball cleaning performance of titanium pipe in the condenser, probably cause the rubber ball to plug the mouth of pipe, the unable through-flow of circulating water, influence the condenser heat exchange. The coating depth of the pipe orifice is at least 20mm, the depth of the pipe orifice is too small, and impurities in seawater are easy to scour the edge coating, so that the coating is reduced quickly.

Step 5, curing the coating;

according to the actual situation, each layer of coating is dried for not less than 72 hours in a natural environment with good ventilation, or the temperature is raised by a baking lamp until the coating is cured, and the curing time is not less than 24 hours; the direct flame baking is forbidden, so that the fire is easy to be dangerous, and the coating effect is not easy to lose effectiveness.

The method is applied to a 3# unit condenser of a 2 x 680MW unit, and relevant data are counted, and the data are shown in table 1.

Comparison table for corrosion prevention conditions of condensers of 2 x 680MW unit #3 unit

As shown in fig. 1, red rust was observed and there was a trace of leakage, but after 1 year of soaking in seawater with the KD-T4 type anticorrosive paint, as shown in fig. 2, it was substantially the same as the original appearance.