阅读说明：本技术 一种防腐蚀油罐及其生产方法 (Anti-corrosion oil tank and production method thereof ) 是由 赖正清 隆荣 曾家群 邹强 谢磊 于 2020-07-07 设计创作，主要内容包括：本发明公开了一种防腐蚀油罐,包括金属罐体和罐体保护层,金属罐体的中部设置有卸料孔,卸料孔上安装有卸料管道和阀门；罐体上端设置有人孔和加油管；人孔上设置有人孔法兰,并配置有密封板对人孔进行密封,加油管上设置有阀门；罐体上设置有检测管,检测管的底部延伸至罐体底部；金属罐体内配置有十字撑杆；罐体保护层粘附在金属罐体内壁。本发明还公开了上述防腐蚀油罐的生产方法。本发明的油罐在制作过程中对焊接点进行了酸洗钝化等保护措施,以提高焊缝的抗腐蚀和抗破坏能力,金属罐体表面进行了粗糙度处理,优化了界面粘结剂的配方,使得保护层能够对金属罐体提供更好的防腐保护。(The invention discloses an anti-corrosion oil tank which comprises a metal tank body and a tank body protective layer, wherein the middle part of the metal tank body is provided with a discharge hole, and a discharge pipeline and a valve are arranged on the discharge hole; the manhole and the oil filling pipe are arranged at the upper end of the tank body; a manhole flange is arranged on the manhole, a sealing plate is configured to seal the manhole, and a valve is arranged on the oil filling pipe; the tank body is provided with a detection pipe, and the bottom of the detection pipe extends to the bottom of the tank body; a cross brace rod is arranged in the metal tank body; the tank body protective layer is adhered to the inner wall of the metal tank body. The invention also discloses a production method of the anti-corrosion oil tank. The oil tank provided by the invention has the advantages that protective measures such as acid pickling passivation and the like are carried out on the butt welding points in the manufacturing process so as to improve the corrosion resistance and the damage resistance of the welding lines, the surface of the metal tank body is subjected to roughness treatment, and the formula of an interface adhesive is optimized, so that the protective layer can provide better corrosion protection for the metal tank body.)

1. An anti-corrosion oil tank is characterized in that: comprises a metal tank body and a tank body protective layer;

the metal tank body comprises a cylinder body and spherical end sockets arranged at two ends of the cylinder body; the cylinder body is made by bending a metal plate into a cylinder shape; the spherical end sockets are welded at two ends of the cylinder body, and reinforcing ribs are welded at the welding positions;

a discharge hole is formed in the middle of the metal tank body, and a discharge pipeline and a valve are mounted on the discharge hole;

the manhole and the oil filling pipe are arranged at the upper end of the tank body; a manhole flange is arranged on the manhole, a sealing plate is configured to seal the manhole, and a valve is arranged on the oil filling pipe;

the tank body is provided with a detection pipe, the bottom of the detection pipe extends to the bottom of the tank body, a monitoring sensor is arranged in the detection pipe, and the monitoring sensor sends a detected signal to the processor through a signal line;

a cross brace rod is arranged in the metal tank body and connected with the metal tank body through an arc-shaped panel to support and maintain the shape of the metal tank body; the tank body protective layer is adhered to the inner wall of the metal tank body.

2. The anti-corrosion oil tank of claim 1, wherein: the bottom of the tank body is provided with supporting legs, and the side wall of the tank body is provided with a liquid level meter.

3. The anti-corrosion oil tank of claim 1, wherein: the tank body is provided with a hoisting plate and a lifting lug, and the monitoring sensor arranged in the detection pipe comprises a temperature sensor and a leakage sensor.

4. The anti-corrosion oil tank of claim 1, wherein: the barrel comprises a plurality of barrel sections, every two barrel sections are welded and connected, and reinforcing ribs are arranged at the welding positions.

5. A method of producing the anti-corrosion oil tank as defined in claims 1 to 4, characterized by comprising the steps of:

cutting a stainless steel material into a preset size, cleaning the stainless steel material, removing rust, sundry scraps and dust on the surface, repairing local scars, and polishing burrs at the edge of a plate; grinding concave-convex points of welding slag burrs on a rounding roller of a plate bending machine smoothly, then rounding a stainless steel material by using the plate bending machine, and then welding and forming an interface; obtaining a cylinder body of the metal tank body;

welding spherical end sockets at two ends of the cylinder, and arranging a circular hole on the cylinder to install a matching device, wherein the matching device comprises a discharge pipeline, a manhole, an oil filling pipe and a detection pipe; welding an arc-shaped panel on the inner wall of the metal tank body, and then arranging a cross-shaped stay bar;

cleaning welding slag splashes on two sides of a welding seam of the cylinder, and removing oil stains on the surface by using a cleaning agent; pickling with acid pickling paste after mechanical polishing, and passivating with passivating paste after pickling; after passivation, cleaning the surface of the welding line by using high-pressure clear water, and then drying the water;

and (4) carrying out anticorrosive treatment on the surface of the metal tank body, wherein the anticorrosive treatment process comprises the following steps: washing the surface of the tank body by using high-pressure clear water, drying the metal tank body by blowing, and spraying the metal anticorrosive paint on the surface of the metal tank body;

step (5) carrying out roughness treatment on the inner surface of the metal tank body to enable the roughness to reach Ra0.3-1.0;

coating an interface binder on the rough surface of the metal tank body, adhering a glass fiber chopped strand mat to the inner surface of the metal tank body, curing the glass fiber chopped strand mat for more than 24 hours at the temperature of more than 20 ℃, and contacting, pressing and cementing to form a glass fiber inner layer; and finally, adhering the glass fiber yarns soaked with the adhesive to the surface of the glass fiber inner layer, and forming a glass fiber protective layer on the innermost layer of the metal tank body.

6. The production method according to claim 5, wherein: the formula of the acid cleaning paste in the step (3) is that each 100g of water contains 20ml of 20% hydrochloric acid, 20g of 35% nitric acid and 150g of bentonite; the formula of the passivation paste is that each 100g of water contains 30ml of 60% nitric acid, 5g of potassium dichromate and 100g of bentonite.

7. The production method according to claim 5, wherein: the acid washing operation comprises the following steps: uniformly coating the acid-reducing washing paste at room temperature on a welding seam to form a 2-5 mm coating, washing the coating for 30-60 min by using high-pressure clear water, and brushing the surface to a smooth surface with white acid corrosion by using a steel wire brush in the washing process;

the passivation operation is as follows: after acid washing, the passivation paste is coated on the welding seam to form a 2-5 mm coating, and a passivation film is formed after 1-2 h of coating.

8. The production method according to claim 5, wherein: the formula of the metal anticorrosive paint in the step (4) is as follows: 40-60 parts of waterborne epoxy resin; 30-40 parts of aluminum-zinc alloy powder; 10-20 parts of polyamide resin; 1-5 parts of graphene; 20 to 40 portions of water;

the preparation method of the metal anticorrosive paint comprises the following steps: adding water into the waterborne epoxy resin, the alloy powder and the graphene, then stirring at a high speed of 600-1200 rpm for 5-10 min, then adding the polyamide resin, and continuing stirring for 5-10 min to obtain the metal anticorrosive coating.

9. The production method according to claim 5, wherein: the roughness treatment method comprises laser etching and sand blasting, and the adhesive is vinyl resin; the thickness of the glass fiber protective layer formed in the metal tank is 5 mm-20 mm.

10. The production method according to claim 5, wherein: the interfacial adhesive comprises the following components by weight: 100 parts of epoxy resin, 20 parts of zinc oxide powder and 10 parts of glyceryl monostearate; 10 parts of triisobutyl phosphate; 10 parts of a curing agent; the curing agent is one or a mixture of more of ethylenediamine, hexamethylenediamine, diethylenetriamine, triethylene tetramine and diethylaminopropylamine.

Technical Field

The invention relates to the technical field of large pressure containers, in particular to an anti-corrosion oil tank and a production method thereof.

Background

The oil storage tank, called oil tank or storage tank for short, is a large container used for storing oil products and having a regular shape, and can be divided into a metal oil tank and a non-metal oil tank according to different construction materials. The metal oil tanks are mostly steel oil tanks, and are a type commonly used in oil depots at present. Steel tanks are mostly made of stainless steel, and have the following types:

(1) vertical cylindrical vault steel oil tank. The capacity is typically under one ten thousand cubic meters. The wall plates are connected in a sleeve mode (fillet welding). The construction is often carried out by a flip-chip method, wherein the tank walls are installed layer by layer from top to bottom from the tank top, and the tank body is lifted by air supplied by a fan.

(2) A vertical cylindrical floating-roof steel oil tank. A double-disk floating roof or a single-disk floating roof which can float up and down is arranged. The double-disc floating roof can reduce the influence of heat radiation, so that the evaporation loss of oil products is small. However, when the capacity is large, a single-disk floating roof is generally adopted in order to reduce the manufacturing cost. The oil tank needs to be good in sealing effect and convenient to install and maintain by selecting a reasonable sealing device. The wall plates are connected by butt welding, and the construction is usually carried out by a normal installation method.

(3) A vertical cylindrical internal floating roof steel oil tank. The floating roof has both a vault and an inner floating roof, and the inner floating roof floats on the liquid level in the vault oil tank and can float up and down. It has the characteristics of floating-roof oil tank, and can ensure the cleanliness of oil product.

(4) Spherical steel oil tank. The liquefied petroleum gas storage tank can bear the working pressure of 0.45-3 MPa, has the capacity of 50-2000 cubic meters generally, and is commonly used for storing liquefied petroleum gas.

The horizontal steel oil tank. The capacity is generally below 50 plum square trees. Gasoline and volatile petroleum products can be stored. The product of the invention belongs to a horizontal rigid oil tank.

Because the medium stored in the oil tank has certain corrosiveness, the surface of the oil tank needs to be treated when the oil tank is produced, and the corrosion degree is reduced.

Reference 1: chinese patent CN201910669167.X anticorrosion spraying method for inner wall of oil tank

The patent discloses an oil tank inner wall anticorrosion spraying method, this oil tank inner wall anticorrosion spraying method, through increasing phosphating treatment before painting, make oil tank inner wall and coating contact completely, prevent effectively that the oil tank inner wall from being corroded by local corrosion, make the adhesion reinforcing of priming paint on the oil tank surface simultaneously, then through the multilayer spraying, make oil tank inner wall anticorrosion coating layer carry out joint protection, can prevent effectively that the oil tank inner wall from corroding, the spraying quality is high, the paint is difficult for droing after the spraying, and anticorrosive time is long, when improving anticorrosive effect, great increase the life of oil tank, better application prospect has.

Reference 2: CN201610813904.5 graphene conductive anticorrosive paint

The patent discloses a graphene conductive anticorrosive paint, which comprises the following components in percentage by mass: potassium water glass: 10-23%; water-based epoxy resin: 5-18%; and (3) graphene oxide: 0.5-2%; tin dioxide nanoparticles: 2-10%; montmorillonite: 3-12%; sodium lignosulfonate: 0.2-5%; auxiliary agent: 0.6-6% of distilled water: 25-45%; the particle size of the tin dioxide is 30 nm-50 nm.

According to the patent, except for graphene oxide, all reagents used in the nano-material tin dioxide and graphene oxide modified anticorrosive paint are cheap and easily available medicines in the market, and tin dioxide nano-particles are creatively added as conductive fillers while the mechanical property of the paint is improved by adding the graphene oxide; because the nano material has small size and large surface energy, the adhesive force of the coating can reach level 1, and the salt spray resistance can reach 1000 hours; the mechanical property of the added graphene oxide is improved, the impact resistance of the coating is 50cm, and the hardness is 6H; the tin dioxide nano particles have low density and are not easy to settle, so that the cured coating has uniform conductivity and the surface resistivity is only 103 omega; besides, the coating disclosed by the invention is simple in preparation process and environment-friendly.

It can be seen in the above documents that the use of modified coatings for treating metal surfaces for corrosion protection is a conventional practice, but the technical results of different coatings are different.

Document 1 discloses a spray coating anticorrosion method and an anticorrosion agent used therein, but the anticorrosion effect of the anticorrosion agent is poor; the anticorrosive paint disclosed in document 2 has a good anticorrosive effect, but the cost thereof is very high.

The outer wall of the metal oil tank is exposed outdoors for a long time, and the metal oil tank is corroded more seriously by the environment and is easy to rust. In the prior art, a metal and glass fiber reinforced plastic double-layer oil tank is available, a glass fiber reinforced plastic layer is arranged on an inner wall to improve the corrosion resistance of the inner wall, and a glass fiber reinforced plastic layer is arranged on an outer wall to improve the corrosion resistance of an outer wall.

However, various stress states such as vibration, torsion, stretching, compression and the like inevitably exist in the use process of the steel product, and the bonding problem of the glass fiber reinforced plastics and the steel which are lined or coated is particularly important. Once the glass fiber reinforced plastic/steel interface develops a crack, corrosive materials can penetrate into the crack and remain therein. At the moment, because the crack is not easy to be found at the interface of the glass fiber reinforced plastic/steel, the local festering corrosion of the steel product can be caused, the leakage of the contained substances in the steel product can be caused if the crack is generated, the environmental pollution can be caused if the crack is generated, and the major accidents such as explosion and the like can be caused if the crack is generated, so the problem of the bonding strength of the glass fiber reinforced plastic/steel structure must be considered when the lining or the outer coating of the.

Document 3: the authors of the test research on the tensile failure mechanism of the composite structure of the glass fiber reinforced plastic/steel connection interface include Zhang Yingjun, Meishiyuan and Zhuxi.

The above documents study the bonding strength of the glass fiber reinforced plastic/steel structure connection interface, modify the binder-epoxy resin by using additives of different types and proportions, and manufacture a series of bonding structure test pieces by using different processes. According to the test results, the tensile failure strength and three typical failure modes of different test pieces are obtained, and the failure mechanism is analyzed.

Document 4: the authors of Lelinjie, Liyainan, Yuanhua, and Yangxuiping, affect of interfacial adhesion on corrosion behavior of GF/VE composites in sulfuric acid media.

From the above documents, it is known that: glass fiber reinforced vinyl ester resin composite (GF/VE) is used as a lead-acid storage battery shell material in corrosive environments such as sulfuric acid, and the corrosion resistance of the glass fiber reinforced vinyl ester resin composite is attracted attention. The corrosion resistance of a GF/VE composite is not only related to the corrosion resistance of the constituent material itself, but also has a great relationship with the interfacial adhesion between the fibers and the resin. In order to study the influence of interfacial adhesion on the corrosion resistance of the GF/VE composite, the mechanical properties of two vinyl ester resins and glass fiber reinforced composites thereof (GF/VE1# and GF/VE2#) were compared, and the mass change rate of the two casting bodies and the composite in a sulfuric acid medium of 40 wt% at 55 ℃ and the change of the static mechanical properties of the composite were studied. The result shows that compared with VE1# resin, the VE2# resin has higher mechanical property and good interface bonding property with glass fiber, so the GF/VE2# composite material has higher interface shear strength. In the sulfuric acid solution, although the mass change rates of the two resin-molded bodies are close to each other, and both the bending property and the shear strength of the composite material are reduced with the increase of the soaking time, the mass change rate and the property retention rate of the two composite materials are different due to the difference of the interface bonding. Research shows that the better the interface bonding performance is, the smaller the contribution of interface moisture absorption to the mass change rate of the composite material is, and the higher the mechanical property retention rate of the composite material is.

From the above-described prior art, the inventors of the present application know that: the properties of different materials after bonding have a direct relationship with the interface treatment method and the composition of the bonding agent. The oil tank is a composite tank body of a metal tank body and a glass fiber reinforced plastic material, so that a novel treatment mode is designed to improve the bonding property between the metal material and the glass fiber reinforced plastic material.

Disclosure of Invention

The invention aims to provide an anti-corrosion oil tank.

To achieve the above object, in one embodiment of the present invention, there is provided an anti-corrosion oil tank including a metal tank body and a tank body protective layer;

the metal tank body comprises a cylinder body and spherical end sockets arranged at two ends of the cylinder body; the cylinder body is made by bending a metal plate into a cylinder shape; the spherical end sockets are welded at two ends of the cylinder body, and reinforcing ribs are welded at the welding positions;

a discharge hole is formed in the middle of the metal tank body, and a discharge pipeline and a valve are mounted on the discharge hole;

the manhole and the oil filling pipe are arranged at the upper end of the tank body; a manhole flange is arranged on the manhole, a sealing plate is configured to seal the manhole, and a valve is arranged on the oil filling pipe;

the tank body is provided with a detection pipe, the bottom of the detection pipe extends to the bottom of the tank body, a monitoring sensor is arranged in the detection pipe, and the monitoring sensor sends a detected signal to the processor through a signal line;

a cross brace rod is arranged in the metal tank body and connected with the metal tank body through an arc-shaped panel to support and maintain the shape of the metal tank body; the tank body protective layer is adhered to the inner wall of the metal tank body.

In the optimized scheme of the invention, the bottom of the tank body is provided with supporting legs, and the side wall of the tank body is provided with a liquid level meter. The tank body is provided with a hoisting plate and a lifting lug, and the monitoring sensor arranged in the detection pipe comprises a temperature sensor and a leakage sensor. The barrel comprises a plurality of barrel sections, every two barrel sections are welded and connected, and reinforcing ribs are arranged at the welding positions.

Another object of the present invention is to provide a method for producing an anti-corrosion oil tank, which can produce an oil tank having better adhesion between a metal layer and a glass fiber reinforced plastic layer and improved interface adhesion strength.

The invention discloses a production method of an anti-corrosion oil tank, which comprises the following steps:

cutting a stainless steel material into a preset size, cleaning the stainless steel material, removing rust, sundry scraps and dust on the surface, repairing local scars, and polishing burrs at the edge of a plate; grinding concave-convex points of welding slag burrs on a rounding roller of a plate bending machine smoothly, then rounding a stainless steel material by using the plate bending machine, and then welding and forming an interface; obtaining a cylinder body of the metal tank body;

welding the spherical end sockets at two ends of the cylinder, and arranging a circular hole on the cylinder to install a matching device, wherein the matching device comprises a discharge pipeline, a manhole, an oil filling pipe and a detection pipe; welding an arc-shaped panel on the inner wall of the metal tank body, and then arranging a cross-shaped stay bar;

cleaning welding slag splashes on two sides of a welding seam of the cylinder, and removing oil stains on the surface by using a cleaning agent; pickling with acid pickling paste after mechanical polishing, and passivating with passivating paste after pickling; after passivation, cleaning the surface of the welding line by using high-pressure clear water, and then drying the water;

and (4) carrying out anticorrosive treatment on the surface of the metal tank body, wherein the anticorrosive treatment process comprises the following steps: washing the surface of the tank body by using high-pressure clear water, drying the metal tank body by blowing, and spraying the metal anticorrosive paint on the surface of the metal tank body;

step (5) carrying out roughness treatment on the inner surface of the metal tank body to enable the roughness to reach Ra0.3-1.0;

coating an interface binder on the rough surface of the metal tank body, adhering a glass fiber chopped strand mat to the inner surface of the metal tank body, curing the glass fiber chopped strand mat for more than 24 hours at the temperature of more than 20 ℃, and contacting, pressing and cementing to form a glass fiber inner layer; and finally, adhering glass fiber yarns soaked with the adhesive to the surface of the glass fiber inner layer, and forming a glass fiber protective layer on the innermost layer of the metal tank body, namely the tank body protective layer.

In the optimized scheme of the invention, the formula of the acid cleaning paste in the step (3) is that each 100g of water contains 20ml of 20% hydrochloric acid, 20g of 35% nitric acid and 150g of bentonite; the formula of the passivation paste is that each 100g of water contains 30ml of 60% nitric acid, 5g of potassium dichromate and 100g of bentonite.

In the optimized scheme of the invention, the pickling operation is as follows: uniformly coating the acid-reducing washing paste at room temperature on a welding seam to form a 2-5 mm coating, washing the coating for 30-60 min by using high-pressure clear water, and brushing the surface to a smooth surface with white acid corrosion by using a steel wire brush in the washing process;

the passivation operation is as follows: after acid washing, the passivation paste is coated on the welding seam to form a 2-5 mm coating, and a passivation film is formed after 1-2 h of coating.

8. The production method according to claim 5, characterized in that: the formula of the metal anticorrosive paint in the step (4) is as follows: 40-60 parts of waterborne epoxy resin; 30-40 parts of aluminum-zinc alloy powder; 10-20 parts of polyamide resin; 1-5 parts of graphene; 20 to 40 portions of water;

the preparation method of the metal anticorrosive paint comprises the following steps: adding water into the waterborne epoxy resin, the alloy powder and the graphene, then stirring at a high speed of 600-1200 rpm for 5-10 min, then adding the polyamide resin, and continuing stirring for 5-10 min to obtain the metal anticorrosive coating.

In the optimized scheme of the invention, the roughness treatment method comprises laser etching and sand blasting, and the adhesive is vinyl resin; the thickness of the glass fiber protective layer formed in the metal tank is 5 mm-20 mm.

In a preferred embodiment of the invention, the interfacial adhesive comprises the following components by weight: 100 parts of epoxy resin, 20 parts of zinc oxide powder and 10 parts of glyceryl monostearate; 10 parts of triisobutyl phosphate; 10 parts of a curing agent; the curing agent is one or a mixture of more of ethylenediamine, hexamethylenediamine, diethylenetriamine, triethylene tetramine and diethylaminopropylamine.

In summary, the invention has the following advantages:

the oil tank provided by the invention has the advantages that protective measures such as acid pickling passivation and the like are carried out on the butt welding points in the manufacturing process so as to improve the corrosion resistance and the damage resistance of welding lines, the tank body protective layer is arranged on the inner side of the metal layer of the oil tank, the surface of the metal tank body is subjected to roughness treatment when the tank body protective layer is arranged, and the formula of an interface adhesive is optimized, so that the adhesive capacity between the metal interface and the protective layer interface is improved, and the protective layer can provide better corrosion protection for the metal tank body.

Drawings

FIG. 1 is a schematic view of an oil tank according to an embodiment of the invention;

FIG. 2 is a schematic view of the installation of a cross brace in accordance with an embodiment of the present invention;

FIG. 3 shows the results of the test in one embodiment of the present invention.

Detailed Description

The invention provides an anti-corrosion oil tank which comprises a metal tank body and a tank body protective layer;

the metal tank body 1 comprises a cylinder body and spherical end sockets 2 arranged at two ends of the cylinder body; the cylinder body is made by bending a metal plate into a cylinder shape; the spherical end sockets are welded at two ends of the cylinder body, and reinforcing ribs are welded at the welding positions;

a discharge hole 3 is formed in the middle of the metal tank body, and a discharge pipeline and a valve are mounted on the discharge hole;

the manhole 4 and the oil filling pipe 5 are arranged at the upper end of the tank body; a manhole flange is arranged on the manhole, a sealing plate is configured to seal the manhole, and a valve is arranged on the oil filling pipe;

the tank body is provided with a detection pipe 6, the bottom of the detection pipe extends to the bottom of the tank body, a monitoring sensor is arranged in the detection pipe, and the monitoring sensor sends a detected signal to the processor through a signal line;

a cross brace rod 8 is arranged in the metal tank body, and the cross brace rod is connected with the metal tank body through an arc-shaped panel 7 and is used for supporting and maintaining the appearance of the metal tank body; the tank body protective layer is adhered to the inner wall of the metal tank body.

In a preferred embodiment of the present invention, in order to support the oil tank, support feet are preferably provided at the bottom of the tank body, and in order to directly and rapidly check the storage amount in the oil tank, a liquid level meter is preferably provided on the side wall of the tank body.

In the preferred embodiment of the invention, the tank body is provided with the hoisting plate and the lifting lug, and the monitoring sensor arranged in the detection pipe comprises a temperature sensor and a leakage sensor.

In the preferred embodiment of the invention, the cylinder body is composed of a plurality of cylinder section bodies, every two cylinder section bodies are welded and connected, and a reinforcing rib is arranged at the welding position.

The production method of the anti-corrosion oil tank comprises the following steps:

cutting a stainless steel material into a preset size, cleaning the stainless steel material, removing rust, sundry scraps and dust on the surface, repairing local scars, and polishing burrs at the edge of a plate; grinding concave-convex points of welding slag burrs on a rounding roller of a plate bending machine smoothly, then rounding a stainless steel material by using the plate bending machine, and then welding and forming an interface; obtaining the cylinder body of the metal tank body.

Welding the spherical end sockets at two ends of the cylinder, and arranging a circular hole on the cylinder to install a matching device, wherein the matching device comprises a discharge pipeline, a manhole, an oil filling pipe and a detection pipe; an arc-shaped panel is welded on the inner wall of the metal tank body, and then a cross-shaped stay bar is arranged.

Cleaning welding slag splashes on two sides of a welding seam of the cylinder, and removing oil stains on the surface by using a cleaning agent; pickling with acid pickling paste after mechanical polishing, and passivating with passivating paste after pickling; and (4) after passivation, cleaning the surface of the welding line by using high-pressure clear water, and then drying the water by blowing.

The formula of the acid cleaning paste in the step (3) is that each 100g of water contains 20ml of 20% hydrochloric acid, 20g of 35% nitric acid and 150g of bentonite. The acid washing operation is as follows: uniformly coating the acid-reducing washing paste at room temperature on a welding seam to form a 2-5 mm coating, washing the coating for 30-60 min by using high-pressure clear water, and brushing the surface to a smooth surface with white acid corrosion by using a steel wire brush in the washing process;

the formula of the passivation paste in the step (3) is that each 100g of water contains 30ml of 60% nitric acid, 5g of potassium dichromate and 100g of bentonite. The passivation operation is as follows: after acid washing, the passivation paste is coated on the welding seam to form a 2-5 mm coating, and a passivation film is formed after 1-2 h of coating.

And (4) carrying out anticorrosive treatment on the surface of the metal tank body, wherein the anticorrosive treatment process comprises the following steps: and (3) washing the surface of the tank body by using high-pressure clear water, drying the metal tank body by blowing, and spraying the metal anticorrosive paint on the surface of the metal tank body.

The formula of the metal anticorrosive paint in the step (4) is as follows: 40-60 parts of waterborne epoxy resin; 30-40 parts of aluminum-zinc alloy powder; 10-20 parts of polyamide resin; 1-5 parts of graphene; 20 to 40 portions of water.

The preparation method of the metal anticorrosive paint comprises the following steps: adding water into the waterborne epoxy resin, the alloy powder and the graphene, then stirring at a high speed of 600-1200 rpm for 5-10 min, then adding the polyamide resin, and continuing stirring for 5-10 min to obtain the metal anticorrosive coating.

Step (5) carrying out roughness treatment on the inner surface of the metal tank body to enable the roughness to reach Ra0.3-1.0;

coating an interface binder on the rough surface of the metal tank body, adhering a glass fiber chopped strand mat to the inner surface of the metal tank body, curing the glass fiber chopped strand mat for more than 24 hours at the temperature of more than 20 ℃, and contacting, pressing and cementing to form a glass fiber inner layer; and finally, adhering the glass fiber yarns soaked with the adhesive to the surface of the glass fiber inner layer, and forming a glass fiber protective layer on the innermost layer of the metal tank body. The roughness treatment method comprises laser etching and sand blasting, and the adhesive is vinyl resin; the thickness of the glass fiber protective layer formed in the metal tank is 5 mm-20 mm.

The interfacial adhesive comprises the following components by weight: 100 parts of epoxy resin, 20 parts of zinc oxide powder and 10 parts of glyceryl monostearate; 10 parts of triisobutyl phosphate; 10 parts of a curing agent; the curing agent is one or a mixture of more of ethylenediamine, hexamethylenediamine, diethylenetriamine, triethylene tetramine and diethylaminopropylamine.