Anti-corrosion construction process for gold welding seam of gasification furnace

Abstract

The invention discloses an anti-corrosion construction process for a gold welding seam of a gasification furnace, which comprises the following steps of: surface treatment: moving along the gasification furnace by using a polishing device, and respectively polishing, derusting, flatly polishing, decontaminating and dedusting original paint layers inside and outside the welding seam; preparing paint, mixing the primer and the finish paint, adding a diluent and a curing agent, and uniformly stirring; primer coating is conducted, specifically, primer coating is conducted after the surface pretreatment experience is qualified, the interval time does not exceed 4 hours, and the treated surface is not allowed to be exposed in air for a long time; after the middle paint, the finish paint and the primer are completely dried, namely, the middle paint, the finish paint and the later paint can be brushed only after the surface of the former paint is dried, so that excellent interlayer adhesive force is ensured, and the interval time does not exceed 48 hours; and handing over for acceptance. Through a whole set of complete construction process of surface treatment, paint preparation, primer coating, intermediate and finishing coat coating and acceptance inspection on the welding seam of the gasification furnace, the welding seam can be subjected to anti-corrosion treatment, so that the welding seam meets the anti-corrosion requirement.

Description

Technical Field

[0001] The present invention relates to the technical field of anti-corrosion processes, and particularly to an anti-corrosion construction process for the golden welds of a gasifier. Background Art

[0002] A gasifier is a device that converts carbon-containing substances (such as coal, biomass, waste, etc.) into combustible gases (syngas, mainly composed of CO, H2, etc.). The welds of the gasifier are key links in its structural safety and operational reliability. Especially in high-temperature, high-pressure, or corrosive environments, the weld quality directly affects the equipment life and safety.

[0003] Argon arc welding (TIG), submerged arc welding (SAW), or laser welding is mostly used to ensure the weld tightness. After welding, anti-corrosion treatment needs to be carried out on the welds. However, the current anti-corrosion treatment for the gasifier welds has the following problems: (1) There is a lack of a complete set of processes for anti-corrosion treatment of the gasifier welds; (2) When performing surface treatment on the welds, both the inside and outside of the welds need to be polished. Before polishing, debris is removed from the welds by manually holding a cleaning brush for pre-cleaning, and then a hand-held angle grinder is used for polishing. After polishing, the debris generated after polishing is removed manually, resulting in low surface treatment efficiency of the welds. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the present invention provides an anti-corrosion construction process for the golden welds of a gasifier to solve the problem of low surface treatment efficiency of the gasifier welds mentioned in the above background art.

[0005] To solve the above technical problems, the present invention provides the following technical solutions:

[0006] An anti-corrosion construction process for the golden welds of a gasifier, comprising the following steps:

[0007] Step 1: Surface Treatment

[0008] Use a grinding device to move along the gasifier and grind the original paint layers on both the inside and outside of the welds respectively to remove rust, smooth, remove dirt, and remove dust, so as to facilitate the inspection of the welds by the inspection unit;

[0009] Step 2: Paint Preparation

[0010] Mix the primer and the topcoat, add a thinner and a curing agent, and stir evenly; before use, let it stand and cure for 15 - 30 minutes, and the curing time is shortened or extended depending on the temperature;

[0011] Step 3: Apply Primer

[0012] Apply the primer after the surface pretreatment is qualified through acceptance, with an interval time not exceeding 4 hours, and it is not allowed to expose the treated surface to the air for a long time;

[0013] Step 4: Apply intermediate and top coats

[0014] After the primer is thoroughly dry, apply the intermediate and top coats. The subsequent coat must be applied after the previous coat has dried on the surface to ensure excellent interlayer adhesion. The interval should not exceed 48 hours.

[0015] Step 5: Final acceptance.

[0016] Preferably, for the internal and external grinding of the welds of the gasifier in Step 1, grind the entire range of 250 mm above and below the welds until smooth, with the welds showing metallic luster, and grind the weld height until smooth.

[0017] Preferably, when grinding flat, remove the welding slag, burrs, and sharp corners on the surface of the component using a grinding device to ensure the aesthetics of the surface coating. When removing dust, after surface treatment, thoroughly remove the surface dust by blowing with a dry and clean air compressor. Do not touch the surface with hands after cleaning to ensure the substrate surface is clean and dry.

[0018] Preferably, in Step 2, when preparing the paint, ensure that the whole barrel of paint is evenly mixed without precipitation and color difference, and do not mix it with conventional paint. For two-component coatings, prepare them strictly according to the material mixing ratio and let them mature for the required time before use. The addition of thinner should be strictly prepared according to the specification, generally not exceeding 5%, and paint materials beyond the expiration date are strictly prohibited from use.

[0019] Preferably, in Step 3, when the atmospheric environment is harsh, such as high humidity or air containing salt mist, further shorten the interval time to ensure no yellow rust appears on the metal surface. The coating should be applied evenly without omission.

[0020] Preferably, in Step 4, it is also necessary to promptly remove the newly adhered dust and debris on the surface of the primer during the coating time interval. If high humidity occurs before it is completely dry, the paint film will turn white. In this case, when recoating, first wipe and clean the white film with a solvent or sandpaper to ensure good interlayer adhesion. The last top coat is applied as a whole to ensure a uniform color without color difference.

[0021] It includes an AGV cart, on which a first hydraulic cylinder is installed. The telescopic end of the first hydraulic cylinder is connected to a side plate. On one side of the side plate, a box body is installed. At both ends of the box body on the side plate, second hydraulic cylinders are hinged. At both ends of the box body, deflection plates are hinged. The telescopic end of the second hydraulic cylinder is movably connected to the deflection plate. On the side of the box body away from the side plate, two first connecting plates are connected. On the two first connecting plates, a first rotating shaft is rotatably connected. On the first rotating shaft, a grinding cylinder is connected by splines. On the side of the deflection plate away from the side plate, two second connecting plates are connected. On the two second connecting plates, a second rotating shaft is rotatably connected. On the second rotating shaft, a cleaning cylinder is connected by splines. A number of cleaning brushes are fixed on the outer wall of the cleaning cylinder. On the box body, a driving mechanism is provided for driving the first rotating shaft and the two second rotating shafts to rotate simultaneously.

[0022] Preferably, the driving mechanism includes a motor installed in the box body, a transmission shaft connected to the motor through a coupling, a driving wheel fixedly connected to the transmission shaft, driven wheels respectively fixedly connected to the first rotating shaft and the second rotating shaft, and a guiding wheel rotatably connected to the box body and close to the grinding cylinder. The driving wheel, the guiding wheel, and the three driven wheels are connected by a transmission belt.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] (1) Through a complete set of construction processes including surface treatment of the welds of the gasifier, paint preparation, primer application, intermediate paint application, and acceptance upon completion, the welds can be subjected to anti-corrosion treatment to meet the anti-corrosion requirements.

[0025] (2) An operation platform is built on the gasifier, and a guide rail is installed on the operation platform to guide the AGV cart. When treating the surface of the welds, control the first hydraulic cylinder to extend, push the side plate, so that the grinding cylinder contacts the welds. Control the second hydraulic cylinder to extend, drive the deflection plate to deflect towards the welds, so that the cleaning brushes contact the welds. The welds are pre-cleaned by the cleaning brushes at one end, the pre-cleaned welds are ground by the grinding cylinder in the middle, and the ground welds are cleaned by the cleaning brushes at the other end. Combined with the work of the AGV cart, automatic pre-cleaning, grinding, and dust removal of the welds are realized, greatly improving the efficiency of surface treatment. Description of the Drawings

[0026] Figure 1 is the process flow chart of the present invention;

[0027] Figure 2 is the schematic diagram of the grinding device;

[0028] Figure 3 is the top view of the grinding device;

[0029] Figure 4 is the top view when grinding the welds;

[0030] In the figure: 1 - AGV cart, 2 - first hydraulic cylinder, 3 - side plate, 4 - box body, 5 - second hydraulic cylinder, 6 - deflection plate, 7 - first connecting plate, 8 - first rotating shaft, 9 - grinding cylinder, 10 - second connecting plate, 11 - second rotating shaft, 12 - cleaning cylinder, 13 - driving wheel, 14 - driven wheel, 15 - guiding wheel, 16 - transmission belt, 17 - gasifier, 18 - track, 19 - operation platform. Specific implementation manner

[0031] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0032] Embodiment 1

[0033] Please refer to Figure 1 , an anti-corrosion construction process for the gold weld of a gasifier, comprising the following steps:

[0034] Step 1: Surface treatment

[0035] Use a grinding device to move along the gasifier, and respectively grind the original paint layers inside and outside the weld, process the welding slag, burrs, and sharp corners on the surface of the component to achieve rust removal and leveling. During grinding, the entire range of 250 mm above and below the weld is ground smoothly, the weld is ground flat to expose the metallic luster, and the height of the weld is ground flat to ensure the aesthetics of the surface coating. After surface treatment, thoroughly remove the surface dust, and blow it with a dry and clean air compressor. The cleaned surface shall not be touched by hand to ensure that the substrate surface is clean and dry, so as to facilitate the weld inspection by the inspection unit.

[0036] Step 2: Paint preparation

[0037] The primer and topcoat should be fully stirred evenly during use to ensure that the whole barrel of paint is evenly without precipitation and color difference, and cannot be mixed with conventional paints. For two-component coatings, the material mixing ratio should be strictly configured, and it should be left to mature for the required time before use. After the paint is proportioned, it is not advisable to reseal it, and it should be configured according to the principle of preparing as much as used. The addition of diluent should be strictly prepared according to the specification, generally not exceeding 5%. Paint materials beyond the service life are strictly prohibited from being used. A special person should add the curing agent to the paint according to the ratio specified in the product instruction manual and stir evenly. Before use, it should be left to stand and mature for 15 - 30 minutes, and the maturation time should be shortened or extended depending on the temperature.

[0038] Step 3: Apply primer

[0039] Primer application: The qualified metal surface after surface pretreatment is submitted for acceptance. After passing the acceptance, the primer should be applied as soon as possible, with an interval not exceeding 4 hours. Prolonged exposure to air is not allowed. In a harsh atmospheric environment (such as high humidity, air containing salt mist), the interval should be further shortened to ensure no yellow rust appears on the metal surface. The application should be uniform without missing any areas.

[0040] Step 4: Intermediate and topcoat application

[0041] After the primer has thoroughly dried (usually 24 hours is sufficient), the intermediate (or topcoat) is applied. The subsequent coat must be applied after the previous coat has dried on the surface to ensure excellent interlayer adhesion. The interval generally does not exceed 48 hours. In addition, any newly adhered dust, debris, etc. on the primer surface during the coating interval should be promptly removed. If high humidity conditions such as snow, rain, or dew occur before the paint is completely dry, the paint film may turn white. In this case, when recoating, the whitened film should be wiped clean with a solvent or sandpaper to ensure good interlayer adhesion. The final topcoat is applied as a whole to ensure a uniform color without color difference.

[0042] Before painting, conduct an appearance inspection on the steel structure surface to ensure that its surface cleanliness and surface roughness meet the specification requirements.

[0043] When the paint surface forms a skin or contains other impurities, it should be filtered and removed before use. When the paint contains fillers that are prone to precipitation, it should be stirred evenly before use.

[0044] The weather requirements for painting are based on the requirements of the paint product instructions. The ideal temperature for the construction environment of the paint is between 4 - 30°C (≥10°C according to the owner's requirements), and the relative humidity is below 85%. Regarding the requirements for the surface after painting, there should be no quality defects such as running, air holes, etc.

[0045] The surface of the object to be painted is dry and free of moisture.

[0046] Sufficient drying time should be left between each coat of paint application, and the specific interval time is determined according to the material properties.

[0047] The paint should not show turbidity, thickening, precipitation, skin formation, etc.

[0048] During construction, there should be no such adverse phenomena on the surface of the object to be painted as running, biting the substrate, bleeding, slow drying, tackiness, surface roughness, blooming, whitening, shrinkage, orange peel, pinholes, etc.

[0049] After construction, there should be no such situations as peeling, powdering, bubbling, cracking, and reflection.

[0050] After the construction is completed, the surface of the object to be painted has a consistent and uniform color, with good film-forming properties, sufficient mechanical strength, and a beautiful appearance.

[0051] During the coating construction process, construction shall be carried out in sequence according to the principle of from top to bottom and from left to right based on the on-site conditions and different object positions. The coating shall be uniform, and there shall be no delamination, wrinkling, missed coating, or wrong coating. To ensure good bonding between coatings, generally, after the first coat is applied, sufficient drying time shall be left before proceeding with the next process to ensure the integrity of the paint film, consistent color, and the coating thickness meeting the design requirements.

[0052] The construction environment and temperature are generally suitable at 4 - 30°C (the construction temperature control for this time is ≥10°C), and the relative humidity shall not be greater than 80%.

[0053] When each coat of the coating is completed, careful inspection shall be carried out. Once quality problems are found, they shall be dealt with immediately. For example, in case of scratches or damages, touch-up coating shall be carried out according to the process to achieve the best anti-corrosion effect.

[0054] The procedure for applying paint shall be from top to bottom, from left to right, first inside and then outside, first difficult parts and then easy parts, and evenly in sequence. When applying paint, it can be brushed horizontally or vertically, and each time, it should overlap by half. Attention shall be paid to maintaining uniformity, especially for areas that are not easily reachable, where touch-up brushing can be carried out. Each coat of the coating shall be uniform, and there shall be no missing, wrinkling, or running.

[0055] To ensure good paint quality, the following ten non-brushing rules shall be observed during construction:

[0056] a. Do not brush when there is rust.

[0057] b. Do not brush when there is dust or oil stain on the surface.

[0058] c. Do not brush when there is rain, snow, or humidity.

[0059] d. Do not brush when there is strong wind.

[0060] e. Do not apply topcoat without primer.

[0061] f. Do not apply the next layer of paint when the underlying paint is not dry.

[0062] g. Do not brush when the temperature does not meet the requirements.

[0063] h. Do not brush when the paint film is damaged.

[0064] i. Do not brush when the humidity exceeds 80%.

[0065] j. Do not brush without inspection.

[0066] Step Five: Final acceptance.

[0067] During the construction process, it should be noted that painting construction is likely to cause secondary pollution, which will contaminate equipment, pipelines, outer protection surfaces, etc. Therefore, during construction, it is necessary to avoid equipment, pipelines, and outer protection surfaces as much as possible. If it is really unavoidable (valve nameplates, valve stems, etc. cannot be painted, especially the protection of the valve stem part, there should be no paint splashing on it, the protection of instruments / valves near the cold box, etc.); colored cloth or billboards can be used to cover equipment, pipelines, and outer protection surfaces; during construction, the paint buckets must be placed stably and firmly to prevent falling and causing secondary pollution; manual and mechanical rust removal will also cause dust pollution, and during construction, the scope and pollution area should be minimized as much as possible. Construction workers should wear masks and protective equipment to prevent dust from entering the mouth and causing personal injuries.

[0068] The used paintbrushes, waste cotton yarn, and used paint buckets after construction are polluting to the soil. These waste tools and material packages should be cleaned up and recycled before getting off work every day, and shall not be discarded randomly. A waste material stacking area should be set up for centralized treatment.

[0069] After the steel members are painted, they should be temporarily enclosed and isolated to prevent trampling and damage to the coating.

[0070] The painted steel members should not be in contact with acidic liquids to prevent the coating from being bitten.

[0071] Example 2

[0072] On the basis of Example 1, please refer to Figure 2 、 Figure 3 、 Figure 4, a grinding device for grinding the gold weld of the gasifier described in claim 6, comprising an AGV cart 1, on which a first hydraulic cylinder 2 is installed. The telescopic end of the first hydraulic cylinder 2 is connected to a side plate 3. On one side of the side plate 3, a box body 4 is installed. At both ends of the box body on the side plate 3, second hydraulic cylinders 5 are hinged. At both ends of the box body 4, deflector plates 6 are hinged. The telescopic end of the second hydraulic cylinder 5 is movably connected to the deflector plate 6. On the side of the box body 4 away from the side plate, two first connecting plates 7 are connected. On the two first connecting plates 7, a first rotating shaft 8 is rotatably connected. On the first rotating shaft 8, a grinding cylinder 9 is connected by splines. On the side of the deflector plate 6 away from the side plate, two second connecting plates 10 are connected. On the two second connecting plates 10, a second rotating shaft 11 is rotatably connected. On the second rotating shaft 11, a cleaning cylinder 12 is connected by splines. A number of cleaning brushes are fixed on the outer wall of the cleaning cylinder 12. Among them, the cleaning brushes at the front end of grinding are wire brushes, and the cleaning brushes at the rear end of grinding are brush bristles. On the box body 4, a driving mechanism for driving the first rotating shaft 8 and the two second rotating shafts 11 to rotate simultaneously is provided. The driving mechanism includes a motor installed in the box body, a transmission shaft connected to the motor by a coupling, a driving wheel 13 fixedly connected to the transmission shaft, driven wheels 14 respectively fixedly connected to the first rotating shaft 8 and the second rotating shaft 11, and a guiding wheel 15 rotatably connected to the box body and close to the grinding cylinder. The driving wheel 13, the guiding wheel 15, and the three driven wheels 14 are connected by a transmission belt 16.

[0073] Circumferential working platforms are respectively built on the inner wall and the outer wall of the gasifier. By the building method, the working platforms are gradually raised from low to high one by one so as to perform surface treatment on each layer of weld. Guide rails are installed on the working platforms. When the gasifier is cylindrical, both the working platform and the guide rail are annular. When the gasifier is rectangular, the working platform is rectangular, and the guide rail is a rounded rectangle. The AGV cart is guided to move through the guide rail. At the same time, a hydraulic system and a control system also need to be installed on the AGV cart. The hydraulic system provides power for the first hydraulic cylinder and the second hydraulic cylinder, and the control system is used to control the motor, the first hydraulic cylinder, the second hydraulic cylinder, and the AGV cart to work.

[0074] The working principle of this embodiment is as follows: The guide rail and the AGV cart are installed. When the gasifier is cylindrical, control the first hydraulic cylinder 2 to extend, push the side plate 3, and make the grinding cylinder 9 contact with the weld. Then control the second hydraulic cylinder 5 to extend, drive the deflector plate 3 to deflect towards the weld, and make the cleaning brush contact with the weld, so as to match gasifiers with different radii. When the gasifier is rectangular, the second hydraulic cylinder 5 does not need to work, and the two deflector plates 3 are on the same straight line. During work, the weld is pre-cleaned by the wire brush at the front end, the pre-cleaned weld is ground by the grinding cylinder in the middle, and the ground weld is cleaned by the brush bristle at the rear end for dust removal. Combined with the movement of the AGV cart along the guide rail, automatic pre-cleaning, grinding, and dust removal of the weld are realized, greatly improving the efficiency of surface treatment.

[0075] It should be noted that the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, such that a process, method, article or apparatus comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or apparatus. Without further limitation, an element defined by the phrase "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or apparatus comprising said element.

[0076] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A corrosion prevention construction process for the gold weld of a gasifier, characterized in that: It includes the following steps: Step 1: Surface treatment Use a grinding device to move along the gasifier, and grind the original paint layers inside and outside the welds respectively to remove rust, smooth, remove dirt and dust, so as to facilitate the weld inspection by the inspection unit; Step 2: Paint preparation Mix the primer and topcoat, add diluent and curing agent, and stir evenly; before use, let it stand and cure for 15 - 30 minutes, and the curing time will be shortened or extended depending on the temperature; Step 3: Apply primer Apply the primer after the surface pretreatment is qualified through acceptance. The interval time shall not exceed 4 hours, and it is not allowed to expose the treated surface to the air for a long time; Step 4: Apply intermediate and topcoats After the primer is thoroughly dry, apply the intermediate and topcoats. The subsequent paint must be applied after the previous paint surface is dry to ensure excellent interlayer adhesion. The interval time shall not exceed 48 hours; Step 5: Handover acceptance.

2. The anti-corrosion construction process for the gold weld of a gasifier according to claim 1, characterized in that: For the grinding of the inside and outside of the gasifier welds in Step 1, the entire range of 250 mm above and below the welds shall be ground, ground smoothly, the welds shall show metallic luster, and the weld height shall be ground smoothly.

3. The anti-corrosion construction process for the gold weld of a gasifier according to claim 2, characterized in that: When smoothing, deal with the welding slag, burrs and sharp corners on the surface of the component, and use a grinding device for treatment to ensure the aesthetics of the surface coating; When removing dust, after the surface treatment is completed, thoroughly remove the surface dust, and use a dry and clean air compressor for blowing. Do not touch the treated surface with hands to ensure that the substrate surface is clean and dry.

4. A corrosion prevention construction process for the gold weld of a gasifier according to claim 3, characterized in that: In Step 2, when preparing the paint, ensure that the whole bucket of paint is evenly without precipitation and color difference, and it cannot be mixed with conventional paint. For two-component coatings, strictly prepare according to the material mixing ratio, and release for use after curing for the required time; the addition of diluent shall be strictly prepared according to the specification, generally not exceeding 5%, and the paint materials beyond the service life are strictly prohibited from use.

5. The anti-corrosion construction process for the gold weld of a gasifier according to claim 4, characterized in that: In Step 3, in a harsh atmospheric environment, such as high humidity or air containing salt mist, the interval time should be further shortened to ensure that no yellow rust appears on the metal surface, and it is required to be applied evenly without missing coating.

6. The anti-corrosion construction process for the golden weld of a gasifier according to claim 5, characterized in that: In Step 4, it is also necessary to promptly remove the newly adhered dust and debris on the surface of the primer during the coating time interval; if high humidity occurs before it is completely dry, the paint film will turn white. In this case, when recoating, first wipe and clean the whitened film with a solvent or sandpaper to ensure good interlayer adhesion; the last topcoat is applied as a whole to ensure a uniform color without color difference.

7. A grinding device for grinding the gold weld of the gasifier described in claim 6, characterized in that: The AGV trolley (1) comprises a first hydraulic cylinder (2) installed on the AGV trolley (1), a telescopic end of the first hydraulic cylinder (2) is connected to a side plate (3), a box (4) is installed on one side of the side plate (3), a second hydraulic cylinder (5) is hingedly connected at both ends of the box on the side plate (3), a deflection plate (6) is hingedly connected at both ends of the box (4), the telescopic end of the second hydraulic cylinder (5) is movably connected to the deflection plate (6), and two first connecting plates (7) are connected on one side of the box (4) away from the side plate. The plate (7) is rotatably connected to a first rotating shaft (8), a grinding cylinder (9) is spline-connected to the first rotating shaft (8), two second connecting plates (10) are connected to the side of the deflection plate (6) away from the side plate, a second rotating shaft (11) is rotatably connected to the two second connecting plates (10), a cleaning cylinder (12) is spline-connected to the second rotating shaft (11), a plurality of cleaning brushes are fixed to the outer wall of the cleaning cylinder (12), and a driving mechanism for driving the first rotating shaft (8) and the two second rotating shafts (11) to rotate simultaneously is provided on the box body (4).

8. The grinding device according to claim 7, characterized in that: The driving mechanism comprises a motor installed in a housing, a transmission shaft connected to the motor through a coupling, a driving wheel (13) fixedly connected to the transmission shaft, a driven wheel (14) fixedly connected to the first rotating shaft (8) and the second rotating shaft (11), and a guide wheel (15) rotatably connected to the housing and close to the grinding cylinder. The driving wheel (13), the guide wheel (15) and the three driven wheels (14) are connected in transmission via a transmission belt (16).

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