Preparation system and method of boiler tube coating

Abstract

The invention relates to the field of boiler tube coatings, in particular to a boiler tube coating preparation system and method. Comprising a conveying assembly, a control system, a preheating unit, a coating unit, a curing unit, a sintering unit and a quenching unit, the control system is connected with the conveying assembly, the preheating unit, the coating unit, the curing unit, the sintering unit and the quenching unit. The conveying assembly and the control system are arranged, the preheating unit, the coating unit, the curing unit, the sintering unit and the quenching unit are sequentially arranged along the conveying assembly, boiler pipe preheating, coating, solid solution sintering and quenching treatment are sequentially carried out, and the boiler pipe with the coating is obtained. The device is reasonable in design, convenient to implement, capable of forming a complete production line of the boiler pipe coating, good in coating quality, high in efficiency and capable of well meeting actual requirements.

Description

Technical Field

[0001] The invention relates to the field of boiler tube coatings, and in particular to a boiler tube coating preparation system and method. Background Art

[0002] Boiler tubes are key components in the boiler responsible for recovering energy from coal-fired flue gas, heating steam, and realizing energy conversion. They are the parts of the boiler that bear the greatest pressure, the highest temperature, and the most demanding service environment. In order to ensure production safety, extend the service life of the pipeline, and reduce economic costs, the tube wall must be pre-strengthened before the boiler tube is put into service. Surface alloying is one of the effective ways to improve the physical and chemical properties of the pipeline surface.

[0003] Surface alloying refers to a technology that changes the composition and structure of the base metal surface by diffusion of metal atoms and chemical reaction with the metal surface layer. In mechanical manufacturing, it is mainly used for surface alloying layers or diffusion layers of aluminum, chromium, silicon, vanadium, zinc, etc.; traditionally, powder coating method or molten salt method is often used, but for the preparation of alloying layer on the surface of long pipes, the coating method may cause large differences in the quality of the alloying layer due to uneven coating, and the molten salt method requires a high temperature environment, high energy consumption and long processing cycle, and the treatment effect is limited for difficult-to-reach areas such as the inside of the pipe; in order to overcome the above difficulties, the metal slurry spraying method will be used. This method first mixes the alloy powder with an appropriate solvent or binder to make a sprayable metal slurry, and then evenly sprays it on the pipe surface through a spray gun and other equipment. This method not only simplifies the operation process and improves the uniformity and adhesion of the coating, but also greatly shortens the processing time and reduces costs.

[0004] For key components in high temperature and high pressure environments such as boiler tubes, their surface alloying layers need to withstand extreme heat treatment processes such as rapid heating and high temperature insulation, which puts higher requirements on the quality, stability and performance of the alloying layers; however, the heat treatment equipment currently on the market often cannot meet these complex and harsh conditions at the same time, resulting in low efficiency of the boiler tube surface alloying process and failure to achieve the expected results. Summary of the invention

[0005] In view of the problems mentioned in the prior art, the present invention proposes a boiler tube coating preparation system and method, which can meet the requirements of rapid heating and high temperature insulation in the boiler tube heat treatment process and improve the efficiency of the boiler tube surface alloying process.

[0006] In order to achieve the above object, the present invention adopts the following technical solution: The present invention discloses a boiler tube coating preparation system, comprising a conveying component, a control system, and a preheating unit, a coating unit, a curing unit, a sintering unit and a quenching unit arranged in sequence along the conveying component; the control system is respectively connected to the conveying component, the preheating unit, the coating unit, the curing unit, the sintering unit and the quenching unit.

[0007] As a further improvement of the present invention, the temperature of the preheating furnace is 60-80° C., and the preheating time is 3-5 minutes.

[0008] As a further improvement of the present invention, the coating unit includes a high-pressure air pump, a coating spray gun and a liquid adsorption pump, wherein the high-pressure air pump injects high-pressure gas into the coating material, the boiler tube is rotationally coated through the coating spray gun, and the coating material is extracted and supplied by the liquid adsorption pump.

[0009] As a further improvement of the present invention, the curing unit includes a burner, an air supply unit and a curing furnace, the burner is used to burn fuel gas, and the burner is connected to the air supply unit; the air supply unit is also provided with a filter, and the filter is used to filter the gas after combustion of the burner, and the air supply unit transports the filtered gas to the curing furnace; a curing cavity is provided inside the curing furnace, and the curing cavity is connected to the air supply unit, and the curing cavity is used to receive the filtered gas, and the curing cavity is used to cure the coating of the boiler tube.

[0010] As a further improvement of the present invention, the burner temperature is 300-450° C., and the curing time is 5-10 minutes.

[0011] As a further improvement of the present invention, the sintering unit comprises a heating furnace for sintering the coating on the surface of the boiler tube, and the heating furnace is used to heat the dry coating to a temperature for sintering the coating.

[0012] As a further improvement of the present invention, the temperature is 850-1150°C.

[0013] As a further improvement of the present invention, the quenching unit includes a high-pressure water gun and a tank body connected to the high-pressure water gun, and the liquid medium is contained in the tank body.

[0014] As a further improvement of the present invention, it also includes a loading device and a unloading device, wherein the loading device is connected to one end of the conveying component, and the unloading device is connected to the other end of the conveying component.

[0015] A method for preparing a boiler tube coating system comprises the following steps: S1: The cleaned boiler tube is conveyed to the preheating unit by the conveying component for preheating, and the preheated boiler tube is conveyed to the coating unit by the conveying component for spraying the coating; S2: The boiler tube after spraying is transported to the curing unit for high temperature boiler tube, and the boiler tube after curing is transported to the sintering unit for high temperature sintering; S3: The sintered high boiler tube is transported to a quenching unit for cooling and quenching to obtain a boiler tube with a coating.

[0016] Compared with the prior art, the present invention has achieved the following technical effects: The present invention provides an efficient and automated boiler tube coating processing system, which combines a transmission component, a control system structure and a coating process unit, realizes the whole process of boiler tube preheating to final quenching treatment, and greatly improves production efficiency and coating quality.

[0017] The preheating unit in the present invention can uniformly preheat the boiler tube to eliminate internal stress and improve the adhesion of the coating; the coating unit is set to uniformly and densely coat the pre-mixed high-quality coating material on the surface of the boiler tube; the curing unit is set to quickly cure the coating material to form a firm bonding layer, and the temperature and time are strictly controlled during the curing process to ensure that the coating quality is stable and reliable; the sintering unit is set to allow the coating to chemically react or physically combine with the boiler tube substrate to further improve the wear resistance, corrosion resistance and other properties of the coating; the quenching unit is set to quickly cool the boiler tube under specific conditions to optimize the material structure.

[0018] The control system of the present invention integrates a PLC programmable logic controller, a human-machine interface (HMI) and a high-precision sensor, and can monitor the working status, temperature, speed and other key parameters of each unit in real time, and automatically adjust the operating parameters according to the preset process curve to ensure that each processing step is carried out under the optimal conditions; the transmission component of the present invention is made of high-strength and wear-resistant materials, which ensures long-term stable operation and can effectively adapt to the transmission requirements of boiler tubes of different specifications and lengths. The transmission component can ensure the stability of the boiler tube during the transmission process and realize fast and accurate positioning, providing a guarantee for subsequent processing units. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic structural diagram of a boiler tube coating preparation system according to an embodiment of the present application is shown.

[0020] Reference numerals: 1. preheating unit; 2. coating unit; 3. curing unit; 4. sintering unit; 5. quenching unit; 6. conveying assembly. DETAILED DESCRIPTION

[0021] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be construed as limiting the present application. On the contrary, the embodiments of the present application include all changes, modifications and equivalents that fall within the spirit and connotation of the appended claims.

[0022] The examples of the present application are described in detail below, and the examples of the examples are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The examples described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0023] like Figure 1 As shown, a boiler tube coating preparation system of the present invention includes a conveying component 6, a control system, and a preheating unit 1, a coating unit 2, a curing unit 3, a sintering unit 4 and a quenching unit 5 arranged in sequence along the conveying component 6; the control system is respectively connected to the conveying component 6, the preheating unit 1, the coating unit 2, the curing unit 3, the sintering unit 4 and the quenching unit 5.

[0024] The preheating unit 1 comprises a preheating furnace, the temperature of the preheating furnace is 60-80° C., and the preheating time is 3-5 minutes. In the embodiment, the preheating furnace can preheat the cleaned boiler tube, so as to improve the adhesion between the subsequent coating and the boiler tube.

[0025] The coating unit 2 includes a high-pressure air pump, a coating spray gun, and a liquid adsorption pump, wherein the high-pressure air pump injects high-pressure gas into the coating material, the coating spray gun performs rotary coating on the boiler tube, and the coating material is extracted and supplied by the liquid adsorption pump. In the embodiment, the high-pressure air pump, the coating spray gun, the liquid adsorption pump, and the metering control chip are specifically used for accurately coating the coating material.

[0026] The coating spray gun speed in the embodiment is 0.1-1 m / s, and the spray gun speed can be adjusted according to specific actual requirements. The coating material in the embodiment is metal powder slurry. Since the existing metal slurry is prone to sedimentation and stratification during storage, the spray gun coating quality cannot meet the requirements. Therefore, the material tank storing the metal slurry in the embodiment needs to be equipped with a stirrer. The stirrer stirs the metal slurry in real time to keep the metal slurry moving at all times, so that the metal slurry will not be deposited or stratified. In the embodiment, the coating spray gun is arranged on a support frame, and the coating spray gun is aligned with the center axis of the boiler tube for coating, and the coating layer thickness is 100-200 μm.

[0027] The embodiment can achieve all-round coating of the boiler tube. The liquid adsorption pump is set to extract the coating material and supply it to the high-pressure air pump. The metering control chip set in the embodiment monitors and controls the amount of coating material sprayed. The monitoring results will be uploaded to the control system, and the spraying amount will be controlled by the control system.

[0028] In the embodiment, the coated boiler tube is dried, and the dried boiler tube is transported to the curing unit 3 for curing. The benefit brought by this is to avoid cracking of the boiler tube coating in the subsequent preparation. In the embodiment, the drying is preferably air-dried, and the air-dried is slowly dried at room temperature. The room temperature is preferably 25-35°C. At the same time, the boiler tube is placed on a rack for air drying during the air drying process. The number of boiler tubes to be air-dried should be no less than 50, which can speed up the air drying efficiency and further improve the overall production efficiency.

[0029] The curing unit 3 includes a burner, an air supply unit and a curing furnace. The burner is used to burn gas, and the burner is connected to the air supply unit. The air supply unit is also provided with a filter, and the filter is used to filter the gas after the burner burns. The air supply unit transports the filtered gas to the curing furnace. A curing cavity is provided inside the curing furnace, and the curing cavity is connected to the air supply unit. The curing cavity is used to receive the filtered gas, and the curing cavity is used to cure the coating of the boiler tube. The burner temperature is 300-450°C, and the curing time is 5-10 minutes.

[0030] In the embodiment, the curing unit 3 specifically includes a burner, an air supply unit, and a curing furnace. The burner is used to burn gas, and the burner is connected to the air supply unit; the air supply unit is also provided with a filter, and the filter is used to filter the gas after the burner burns, and the air supply unit transports the filtered gas to the curing furnace; a curing cavity is provided inside the curing furnace, and the curing cavity is connected to the air supply mechanism, and the curing cavity is used to receive the filtered gas; in the embodiment, the curing cavity is provided with a temperature sensor, and the temperature sensor and the burner are both connected to the control system, and the control system receives the temperature signal sent by the temperature sensor, and can adjust the heat output by the burner according to the temperature signal.

[0031] When in use, the burner generates high-temperature gas after burning fuel gas. The filter filters the high-temperature gas after combustion to prevent dust in the high-temperature gas from entering the curing chamber. The air supply mechanism transports the high-temperature gas to the curing chamber. The temperature sensor detects the temperature of the curing chamber and sends the temperature signal to the control system. The control system adjusts the heat output of the burner according to the temperature signal to control the temperature in the curing chamber to remain at 300-450°C, and at the same time controls the required curing time according to the control system.

[0032] In the embodiment, the heat generated by the burner burning gas is generally greater than that of the electric heater, and the working temperature is also higher, that is, the temperature required for the curing of the boiler tube coating will be raised faster; the filter can solve the problem of dust generated by the burning gas entering the curing cavity, and avoid the dust affecting the curing quality of the boiler tube coating. After the curing is completed, high-temperature sintering is performed immediately in the embodiment to ensure the curing quality.

[0033] The sintering unit 4 includes a heating furnace for sintering the coating on the surface of the boiler tube, and the heating furnace is used to heat the dry coating to a temperature for sintering the coating. The temperature is 850-1150°C. In the embodiment, the sintering unit 4 is a heating furnace, which is used to further heat the temperature of the boiler tube coating from the curing temperature to a sintering temperature preferably between 850°C and 1150°C. The heating furnace is provided with a plurality of nozzles, each of which emits a heating gas to heat the boiler tube coating to further increase the temperature; in the embodiment, another nozzle can be arranged in the sintering unit 4 to emit an inert gas to provide protection for the entire sintering process, so as to optimize the sintering process and ensure that the boiler tube material does not bend or deform during the sintering process. In the embodiment, the inert gas is preferably Ar gas or N2 gas.

[0034] In the embodiment, a temperature sensor is also provided in the heating furnace. The control system is connected to the heating furnace and the temperature sensor. The temperature in the heating furnace can be detected in real time by the provided temperature sensor, thereby ensuring the quality of the sintering process. The control system receives the temperature signal sent by the temperature sensor and can adjust the heat output of the heating furnace according to the temperature signal.

[0035] The quenching unit 5 includes a high-pressure water gun and a tank body connected to the high-pressure water gun, and a liquid medium is contained in the tank body. In the embodiment, there is at least one high-pressure water gun, and multiple high-pressure water guns can be provided according to production requirements. The liquid medium in the embodiment is preferably water, oil or liquid nitrogen, and the surface of the boiler tube coating can be quickly cooled by the liquid medium. After cooling, the whole process can be completed by naturally air drying at room temperature.

[0036] It also includes a loading device and a unloading device, wherein the loading device is connected to one end of the conveying assembly 6, and the unloading device is connected to the other end of the conveying assembly 6. The loading device and the unloading device in the embodiment both include a mounting frame, a linear guide rail arranged on the mounting frame, and a grabbing mechanism arranged on the linear guide rail. The grabbing mechanism arranged can be used to realize the transmission of the boiler tube through the conveying assembly 6, and after the boiler tube is transported to the preheating unit 1, the coating unit 2, the curing unit 3, the sintering unit 4 and the quenching unit 5 in sequence through the conveying assembly 6, the coated boiler tube is unloaded through the unloading device. The linear guide rail in the embodiment realizes the grabbing and carrying operation of the boiler tube in the horizontal direction by controlling the movement of the grabbing mechanism on the linear guide rail; the grabbing mechanism in the embodiment is preferably a vacuum suction cup, and the vacuum suction cup is used to absorb and grab the boiler tube to realize transportation. The loading device and the unloading device in the embodiment are both connected to the control system, and the process of automatic loading and automatic unloading is realized through the control system.

[0037] In the embodiment, the transmission component 6 includes a conveyor belt and a driving mechanism connected to the conveyor belt. The driving mechanism provides power to drive the conveyor belt to move, thereby realizing the transportation of the boiler tube. The driving mechanism is connected to the control system, and the control system is used to control the transportation rate. The driving mechanism is preferably a motor, but is not limited to this, and can also be other mechanisms that can drive the conveyor belt to move.

[0038] The control system in the embodiment is a PLC control system with high integration and reliability. The system can completely monitor and record the operating status of the entire device, and can monitor and adjust key parameters. The control system can monitor the temperature of the preheating unit 1, the curing unit 3, and the sintering unit 4 in real time, so that the temperature of each process of the boiler tube during the entire process is guaranteed to be within the preset temperature. By sensing the temperature changes of each unit in real time, the temperature and time required to be output by each unit are adjusted, and the quality of the boiler tube coating is further improved.

[0039] The present invention provides an efficient and automated boiler tube coating processing system, which combines a transmission component, a control system structure and a coating process unit, realizes the whole process of boiler tube preheating to final quenching treatment, and greatly improves production efficiency and coating quality.

[0040] Example 2 This embodiment is basically the same as Embodiment 1, except that this embodiment provides a process method for a boiler tube coating preparation system, comprising the following steps: boiler tube cleaning; preheating the boiler tube and then coating it; heating, curing and high-temperature sintering the coated boiler tube; and cooling and quenching the boiler tube.

[0041] Specifically, austenitic 304 stainless steel pipes are selected; inner diameter: 20mm; length: 5m.

[0042] According to the above boiler tube coating preparation system process flow is as follows: Loading - Preheating unit preheating (60-80℃, 3-5min) - Coating unit spraying slurry - Unloading - Natural air drying (25-35℃, ventilation) - Loading - Curing unit curing (300-450℃, ventilation) - Sintering unit sintering (850-1150℃) - Quenching (rapid water cooling) - Unloading.

[0043] The whole process parameter requirements: Preheating unit: preheating temperature: 60-80℃; time: 3-5min (based on the time the pipe is fully heated); temperature and time can be adjusted according to pipes of different sizes; precise temperature control, the temperature control accuracy is within ±3℃ after the equipment is stable, and the pipe enters the coating unit after preheating.

[0044] Coating unit: Spraying rate: 0.1-1 m / s and continuously adjustable; the spray gun is aligned with the center axis of the pipe; the spray slurry is metal powder slurry (the slurry is prone to sedimentation and stratification), and the material tank needs to have a stirring function; the spray layer thickness is 100-200μm; Natural air drying: The coating is slowly air dried at room temperature (about 25-35 ℃); air circulation is required inside the tube, and the flow rate should not be too high. The material rack in the air drying stage should have a storage capacity of no less than 50 tubes.

[0045] Curing unit: Curing temperature: 300-450℃; time: 5-10 min; temperature and time can be adjusted according to different sizes of pipes; proper ventilation is maintained in the pipe; high-temperature sintering is carried out immediately after curing.

[0046] Sintering unit: sintering temperature 950~1100 ℃, temperature control accuracy ±5 ℃ after stabilization; sintering time 8-15 min; temperature and time can be adjusted as needed; the inner wall of the tube is protected by inert atmosphere (Ar gas or N2 gas) throughout the sintering process; the sintering process requires that the tube does not bend or deform.

[0047] Quenching unit: After sintering, the pipe is quenched and quickly cooled. The cooling method is to rinse with a water gun and then dry naturally.

[0048] It should be noted that, in the description of this application, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. In addition, in the description of this application, unless otherwise specified, the meaning of "plurality" is two or more.

[0049] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, segment or portion of code that includes one or more executable instructions for implementing the steps of a specific logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present application belong.

[0050] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0051] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A boiler tube coating preparation system, characterized in that: It includes a conveying component, a control system, and a preheating unit, a coating unit, a curing unit, a sintering unit and a quenching unit arranged in sequence along the conveying component; the control system is connected to the conveying component, the preheating unit, the coating unit, the curing unit, the sintering unit and the quenching unit respectively.

2. A boiler tube coating preparation system according to claim 1, characterized in that: The preheating unit comprises a preheating furnace, the temperature of the preheating furnace is 60-80° C., and the preheating time is 3-5 minutes.

3. A boiler tube coating preparation system according to claim 1, characterized in that: The coating unit includes a high-pressure air pump, a coating spray gun and a liquid adsorption pump, wherein the high-pressure air pump injects high-pressure gas into the coating material, the coating spray gun performs rotational coating on the boiler tube, and the coating material is extracted and supplied by the liquid adsorption pump.

4. A boiler tube coating preparation system according to claim 1, characterized in that: The curing unit includes a burner, an air supply unit and a curing furnace, wherein the burner is used to burn fuel gas, and the burner is connected to the air supply unit; the air supply unit is also provided with a filter, and the filter is used to filter the gas after combustion by the burner, and the air supply unit transports the filtered gas to the curing furnace; a curing cavity is provided inside the curing furnace, and the curing cavity is connected to the air supply unit, and the curing cavity is used to receive the filtered gas, and the curing cavity is used to cure the coating of the boiler tube.

5. A boiler tube coating preparation system according to claim 4, characterized in that: The burner temperature is 300-450° C., and the curing time is 5-10 minutes.

6. A boiler tube coating preparation system according to claim 1, characterized in that: The sintering unit includes a heating furnace for sintering the coating on the surface of the boiler tube, and the heating furnace is used to heat the dry coating to a temperature for sintering the coating.

7. A boiler tube coating preparation system according to claim 6, characterized in that: The temperature is 850-1150°C.

8. A boiler tube coating preparation system according to claim 1, characterized in that: The quenching unit comprises a high-pressure water gun and a tank body connected to the high-pressure water gun, and a liquid medium is contained in the tank body.

9. A boiler tube coating preparation system according to claim 1, characterized in that: It also includes a loading device and a unloading device, wherein the loading device is connected to one end of the conveying component, and the unloading device is connected to the other end of the conveying component.

10. A method for preparing a boiler tube coating system according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1: The cleaned boiler tube is conveyed to the preheating unit by the conveying component for preheating, and the preheated boiler tube is conveyed to the coating unit by the conveying component for spraying the coating; S2: The boiler tube after spraying is transported to the curing unit for high temperature boiler tube, and the boiler tube after curing is transported to the sintering unit for high temperature sintering; S3: The sintered high boiler tube is transported to a quenching unit for cooling and quenching to obtain a boiler tube with a coating.

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