A probe device and method for testing the high temperature corrosion resistance of metal materials on the heating surface of a garbage incineration boiler

Abstract

The present invention discloses a probe device and method for testing the high-temperature corrosion resistance of the metal material of the heating surface of a waste incineration boiler, which can be used to conduct an online high-temperature corrosion simulation test of the heating surface in the furnace of a waste incineration power plant. The present invention realizes the controllability of the temperature of the test piece through the gas reflux design of the inner and outer sleeves and the independently sealed internal space. In order to avoid the influence of galvanic corrosion caused by direct contact of different metals due to connection methods such as welding or threads on the experimental results, the present invention adopts a split tightening clamp flange as a connecting component connecting the test piece and the main body of the device, and fills a high-temperature resistant rubber gasket between the flange and the test piece as a barrier layer. This also ensures the good sealing of the device and realizes the convenient disassembly and assembly of the test piece. The present invention has a simple design, is easy to carry, and has a wide range of uses. It can realize the test of the high-temperature corrosion resistance of different metal materials in waste incineration power plants, and is suitable for on-site research on high-temperature corrosion of boiler heating surfaces.

Description

Technical Field

[0001] The invention belongs to the field of high-temperature corrosion of metals, and in particular relates to a probe device and a method for testing the high-temperature corrosion resistance of a metal material on a heating surface of a garbage incineration boiler. Background Art

[0002] In recent years, my country's waste incineration industry has developed rapidly. In 2017, my country has built and put into operation 286 domestic waste incineration harmless treatment plants. Although the number is far from comparable to domestic waste sanitary landfill harmless treatment plants, there is a great momentum to replace them.

[0003] However, due to the wide variety and complex composition of domestic waste, many problems have occurred in the actual operation of the waste incineration system. Among them, the high-temperature corrosion of the boiler heating surface is particularly prominent. During the on-site inspection, the main high-temperature heating surfaces such as superheaters, economizers, and even water-cooled walls, air preheaters and other relatively low-temperature parts were found to have different degrees of corrosion.

[0004] For this type of research, in addition to the mechanism research experiments conducted in the laboratory, some field tests are also needed to verify the theoretical results of the laboratory and to screen materials with excellent performance.

[0005] Traditional on-site corrosion tests mostly use the hanging plate method, and its test cycle is easily restricted by the factory's production conditions and maintenance plans, which is relatively passive. Since the actual heating surface material is usually heated in the furnace on one side with a higher temperature, and the other side is in the external environment or in contact with the low-temperature working medium with a relatively low temperature, its wall temperature is often lower than the flue gas temperature in the furnace. The hanging plate method in the furnace cannot simulate the actual wall temperature, which is also a major disadvantage of the hanging plate method.

[0006] In order to improve flexibility and accuracy, some researchers have developed probe devices for online simulation of corrosion tests. The basic principle of the probe is to simulate the actual corrosion process of the heated surface. Generally, the external temperature of the heated surface is simulated by air cooling or water cooling, so as to achieve controllable simulation of temperature conditions. However, the existing corrosion probe devices are roughly designed and the temperature simulation is imperfect. For example, the annular test piece is directly sleeved on the outer surface of the steel pipe with interference fit, and the steel pipe is cooled by air, which has a large temperature transfer resistance. Moreover, most of them do not pay attention to the influence of galvanic corrosion and stress corrosion, which violates the general principles of metal corrosion tests, such as direct contact between different metals or welding process between metals [PHONGPHIPHAT A, RYU C, YANG Yao-bin, et al. Investigation into high-temperature corrosion in a large-scale municipal waste-to-energy plant]. Relatively speaking, a probe device with a simple design, portability, easy operation and conforming to the general principles of metal corrosion tests will have a wider range of applications and better application prospects. Summary of the invention

[0007] The present invention provides a probe device and method for testing the high temperature corrosion resistance of the metal material of the heating surface of a waste incineration boiler, which can be installed and disassembled online at any time during the operation of the boiler, and is easy to operate. The present invention adopts a simple and flexible installation method, and the tubular design is easy to carry, has a wide range of applications, and has good economy and scope of application.

[0008] In order to achieve the above object, the present invention adopts the following technical solution:

[0009] A probe device for testing the high temperature corrosion resistance of the metal material of the heating surface of a waste incineration boiler comprises an outer sleeve, an inner sleeve coaxially installed with the outer sleeve, a tubular test piece assembled at the outlet end of the outer sleeve, a top end cover for fixing the tubular test piece, a thermocouple passing through the inner sleeve, and a gas path; a gap is left between the inner tube wall of the outer sleeve and the outer tube wall of the inner sleeve;

[0010] The outlet end of the inner sleeve is at the same end as the outlet end of the outer sleeve and is located inside the outer sleeve; the inlet end of the inner sleeve is at the same end as the inlet end of the outer sleeve and is located outside the outer sleeve; the inlet end of the inner sleeve is provided with a groove for installing a thermocouple; the inner sleeve is provided with a cooling gas inlet with an opening and closing valve;

[0011] The inlet end of the outer sleeve is sealed with the outer tube wall of the inner sleeve, so that a sealed passage for gas circulation is formed between the inner tube wall of the outer sleeve and the outer tube wall of the inner sleeve; a heated gas outlet with an opening and closing valve is provided on the outer sleeve;

[0012] The thermocouple is connected to a thermocouple display and is fixed in a clamp manner in a nested groove at the inlet end of the inner sleeve. The temperature measuring end of the thermocouple passes through the tubular test piece and abuts against the top end cover.

[0013] As a preferred embodiment of the present invention, a rubber gasket is provided on the contact surface between the top end cover and the tubular test piece.

[0014] As a preferred embodiment of the present invention, the tubular test piece is connected to the outer sleeve outlet end by flange connection, a first flange is welded to the outer sleeve outlet end, and the first flange is bolted to the top end cover fixing the tubular test piece.

[0015] As a preferred embodiment of the present invention, the top end cover includes a split clamp flange and a split clamp flange end cover; the tubular specimen is installed between the split clamp flange and the split clamp flange end cover, coaxial with the outer sleeve; the first flange, the split clamp flange and the split clamp flange end cover are connected by positioning bolts.

[0016] As a preferred embodiment of the present invention, the gas path includes a cooling gas inlet pipe and a heated gas outlet pipe; one end of the cooling gas inlet pipe is connected to the cooling gas inlet on the inner sleeve, and the other end is connected to the compressed air source; one end of the heated gas outlet pipe is connected to the heated gas outlet on the outer sleeve, and the other end is a free end.

[0017] As a preferred embodiment of the present invention, it further comprises a furnace wall outer surface flange and an outer sleeve flange fixed on the outer tube wall of the outer sleeve, wherein the outer sleeve flange is fixed to the furnace wall via the furnace wall outer surface flange.

[0018] Compared with the existing corrosion probe technology, the present invention has the following beneficial effects:

[0019] (1) Compared with the on-site corrosion hanging method, the present invention controls the surface temperature of the specimen by adjusting the flow rate of compressed air flowing in the gap between the inner and outer sleeves, thereby achieving self-control of the surface temperature of the specimen.

[0020] (2) The high-temperature resistant rubber barrier design between the flange and the test piece avoids direct contact between different metals and effectively eliminates the influence of galvanic corrosion.

[0021] (3) The device is connected to the furnace wall by a movable split clamp flange. The insertion depth of the device can be freely adjusted, which also makes the test device easy to install and disassemble.

[0022] (4) The use of split clamp flanges at both ends of the specimen and positioning bolts in the test area enables the specimen to be removed without direct contact with the specimen surface after the test is completed, thus avoiding damage to the fragile corrosion layer when removing the specimen and improving the accuracy of the test data.

[0023] (5) The probe device of the present invention can be installed and disassembled online at any time during the operation of the boiler, and is easy to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A schematic diagram of the structure and installation of a probe device for testing the high-temperature corrosion resistance of metal materials on the heating surface of a waste incineration boiler provided by the present invention;

[0025] Figure 2 The present invention provides Figure 1 A is a partial enlarged full cross-sectional schematic diagram;

[0026] Figure 3 A front view of components 7, 14, and 17 provided by the present invention;

[0027] The meanings of the symbols in the above figure are as follows:

[0028] Thermocouple display 1, thermocouple 2, inner sleeve 3, inner sleeve inlet end 3a, inner sleeve outlet end 3b, cooling gas inlet 4, heated gas outlet 5, heated gas outlet pipe 6, outer sleeve flange 7, furnace wall outer surface flange 8, furnace wall 9, outer sleeve 10, outer sleeve inlet end 10a, outer sleeve outlet end 10b, test piece 11, fireproof cotton 12, first flange 13, split clamp flange 14, positioning bolt 15, high temperature resistant rubber gasket 16a, high temperature resistant rubber gasket 16b, split clamp flange end cover 17, top cover groove 18. DETAILED DESCRIPTION

[0029] like Figure 1 , 2 As shown, the probe device for testing the high-temperature corrosion resistance of metal materials includes a thermocouple display 1, a thermocouple 2, an inner sleeve 3, an inner sleeve inlet end 3a, an inner sleeve outlet end 3b, a cooling gas inlet 4, a heated gas outlet 5, a heated gas outlet pipe 6, an outer sleeve flange 7, a furnace wall outer surface flange 8, a furnace wall 9, an outer sleeve 10, an outer sleeve inlet end 10a, an outer sleeve outlet end 10b, a test piece 11, fireproof cotton 12, a first flange 13, a split clamp flange 14, a positioning bolt 15, a high-temperature resistant rubber gasket 16a, a high-temperature resistant rubber gasket 16b, a split clamp flange end cover 17, and a top cover groove 18.

[0030] Among them, the front view of the outer sleeve flange 7, the split clamp flange 14, and the split clamp flange end cover 17 is as shown in Figure 3 shown.

[0031] As a preferred embodiment of the present invention, the outlet end of the inner sleeve is at the same end as the outlet end of the outer sleeve, located inside the outer sleeve, and this end is completely open; the inlet end of the inner sleeve is at the same end as the inlet end of the outer sleeve, located outside the outer sleeve, the inlet end of the outer sleeve and the outer tube wall of the inner sleeve are sealed, and a gap is left between the inner and outer sleeves for gas circulation; the inlet end of the inner sleeve is provided with a groove for installing a thermocouple.

[0032] As a preferred embodiment of the present invention, a cooling gas inlet is provided on the outer tube wall of the inner sleeve and is close to the inlet end of the inner sleeve. The cooling gas inlet is provided with an opening and closing valve device and is connected to the cooling gas inlet pipeline; a heated gas outlet is provided on the outer tube wall of the outer sleeve and is close to the inlet end of the outer sleeve. The heated gas outlet is provided with an opening and closing valve device and is connected to the heated gas outlet pipeline, and the pipeline material is high-temperature resistant alloy steel.

[0033] As a preferred embodiment of the present invention, the outer sleeve is made of high-temperature corrosion-resistant alloy steel, with a circular cross-sectional shape, and the inner sleeve has the same cross-sectional shape as the outer sleeve; the tubular test piece is a certain metal material to be tested, with a circular cross-sectional shape, and is tubular as a whole. The connection method with the outlet end of the outer sleeve is flange connection, and all places where the flange and the test piece may contact are blocked by high-temperature resistant rubber gaskets. Combined with the example, the production process of the probe device is as follows: Figure 1 As shown, the outer sleeve 10 is the main part of the device, and other components can be considered to be installed on its basis.

[0034] First, select the metal material to be tested and make a tubular specimen 11. Install the split clamp flange 14 at one end of the specimen 11. During installation, pad the inner ring surface of the split clamp flange 14 with a high-temperature resistant rubber gasket 16a, and pad the end face of the specimen 11 with a high-temperature resistant rubber gasket 16b to prevent the split clamp flange 14 from directly contacting the outer surface of the specimen 11, and then tighten the tightening bolts of the split clamp flange 14. Install the split clamp flange end cover 17 at the other end of the specimen 11. During installation, pad the inner ring and end face of the clamp flange with a high-temperature resistant rubber gasket 16a and a high-temperature resistant rubber gasket 16b to prevent the split clamp flange end cover 17 from directly contacting the outer surface of the specimen 11. The split clamp flange 14 and the split clamp flange end cover 17 at both ends of the specimen 11 are each provided with four bolt holes, and the bolt holes of the two flanges must be completely aligned during installation.

[0035] Then, manufacture the outer sleeve 10. The outer sleeve 10 is made of alloy steel resistant to high temperature corrosion. Its length is determined according to the depth of the outer sleeve inserted into the furnace through the furnace wall during the test. Its thickness is larger than the thickness of the test piece 11. Specifically, the inner diameter of the outer sleeve 10 is required to be equal to the inner diameter of the test piece 11, while the outer diameter is larger than the outer diameter of the test piece 11. After determining its length and thickness, weld the first flange 13 at its outlet end 10b. Four bolt holes are opened on the first flange for docking with the flange on the test piece. During installation, the bolt holes of the first flange 13 must be completely aligned with the bolt holes of the split clamp flange 14 and the split clamp flange end cover 17. After the holes of the three flanges are aligned, install four positioning bolts 15. The installation of the positioning bolts 15 is as follows: Figure 2 For example, the bolt head is located on the left side of the first flange 13, the screw is inserted from the flange hole on the outer sleeve, and passes through the split clamp flange 14 and the split clamp flange end cover 17 in sequence. After passing through the split clamp flange 14, two nuts are installed on the screw to connect and fix the first flange 13 and the split clamp flange 14. After passing through the bolt hole on the split clamp flange end cover 17, two nuts are installed on the screw on the right side of the split clamp flange end cover 17 to fix the installation position of the split clamp flange end cover 17. Note that during assembly, a high-temperature resistant sealing rubber gasket is placed between the first flange 13 and the split clamp flange 14 to prevent gas leakage and maintain the overall airtightness of the device. The split clamp flange end cover 17 here can be left uninstalled and installed when the thermocouple is installed.

[0036] After that, the inner sleeve 3 is installed. The outer diameter of the inner sleeve 3 is smaller than the inner diameter of the outer sleeve 10, so as to leave a passage for gas flow between the inner and outer sleeves. The inner sleeve 3 can be made of ordinary steel and is a through pipe as a whole. The inlet end 3a is processed with external threads, and the outlet end 3b is not processed and is completely open. The inner sleeve 3 is inserted from the inlet end 10a of the outer sleeve. Figure 2 As shown, the insertion depth of the inner sleeve 3 is approximately where its outlet end 3b is aligned with the first flange 13. After the position is determined, in order to ensure that the inner sleeve 3 is installed concentrically with the outer sleeve 10, welding rods are used to perform three-point fixation between the outer wall of the inner sleeve 3 and the inner wall of the outer sleeve 10. After fixation, the gap between the inlet end 10a of the outer sleeve and the outer surface of the inner sleeve 3 is closed by welding.

[0037] Afterwards, if Figure 1 A hole is opened on the side of the outer wall near the inlet end 10a of the outer sleeve, and the hole diameter is equal to the inner diameter of the outer sleeve 10. After the hole is opened, a heated gas outlet 5 is welded on the hole, and threads are cut on the heated gas outlet 5 for installing the valve. Threads are also cut on the valve for installing the heated gas outlet pipe 6. The heated gas outlet pipe 6 is made of high-temperature resistant alloy steel.

[0038] Afterwards, if Figure 1 A hole is made on the side of the outer wall near the inlet end 3a of the inner sleeve, and the hole size is equal to the inner diameter of the cooling gas inlet pipe. After the hole is made, a cooling gas inlet 4 is welded on the hole, and threads are cut on the cooling gas inlet 4 for installing the valve. The valve is also threaded for installing the cooling gas inlet pipe. It should be noted here that in the field example, the cooling gas inlet pipe design uses a special pipe for the compressed air cabinet of the waste incineration power plant, so there is no need to prepare the pipe by yourself. When making the device, you only need to make the cooling gas inlet valve according to the standard pipe diameter of the compressed gas used in the power plant.

[0039] Finally, install the thermocouple 2. The thermocouple 2 is a K-type thermocouple. Before installation, ensure that the length of the thermocouple 2 is long enough, that is, at least longer than the distance between the inner sleeve inlet end 3a and the top end cover of the device. The installation method of the thermocouple 2 is: insert from the inner sleeve inlet end 3a, and push the front measuring end into the top cover groove 18 reserved in the center of the split clamp flange end cover 17 (such as Figure 2 As shown), then install the split clamp flange end cover 17, tighten the nut of the positioning bolt 15, and tighten the clamp bolt of the split clamp flange end cover 17. The installation position of the thermocouple 2 is thus determined. After that, a small clamp is put on the measuring extension rod of the thermocouple 2, and then the clamp sleeve is embedded in the pre-processed groove at the inlet end 3a of the inner sleeve, the clamp sleeve is locked, and then the bolt cap is covered to complete the installation of the thermocouple 2. At this point, the production of the probe device is completed.

[0040] When in use, a hole is made in the wall of an appropriate part of the boiler. The size of the hole should be such that the probe device can be inserted, that is, it should be at least larger than the overall diameter of the top test piece. After the hole is made, the flange 8 on the outer surface of the furnace wall is installed; the cooling gas inlet and the compressed air source are connected, but compressed air is not introduced temporarily; the probe device is extended into the furnace through the furnace wall from the opening and installed at 90° to the flue gas flow, so that the position of the test piece is completely exposed to the flue gas scouring in the furnace. After the probe device is inserted, since the overall diameter of the top test piece is larger than the diameter of the outer casing body, it is necessary to add fillers between the furnace wall and the probe for fixation, such as Figure 1As shown, adding fireproof cotton 12 does not need to completely fill the space, but only needs to fill the space below the device to play a supporting role, so as to prevent the head of the device from sagging due to gravity. Tighten the outer sleeve flange 7 on the outer sleeve 10, and assemble and fix it with the flange 8 on the outer surface of the furnace wall; connect the data line of the thermocouple display instrument 1 and the thermocouple 2, and observe the currently measured temperature of the test piece; then fully open the pipeline valve of the heated gas outlet 5, and adjust the opening of the cooling gas inlet 4 valve to the maximum; after the compressed air is introduced, the cooling gas enters the inner sleeve from the cooling gas inlet 4, and enters the sealed channel for gas circulation between the inner tube wall and the outer tube wall of the inner sleeve after reaching the outlet end of the inner sleeve, and then is discharged from the heated gas outlet on the outer sleeve, the temperature of the test piece begins to decrease, and the opening of the cooling gas inlet valve is reduced, so that the temperature of the test piece is raised to the required temperature for the test before starting the test. After a period of time, when the time required for the test is reached, the outer sleeve flange 7 is removed, and the probe device is taken out from the furnace wall to complete the test. The test piece is removed without directly contacting the surface of the test piece, thereby avoiding damage to the fragile corrosion layer when removing the test piece. When the next experiment is required, only the test piece needs to be replaced.

Claims

1. A probe device for testing the high temperature corrosion resistance of metal materials on the heating surface of a waste incineration boiler, characterized in that: It comprises an outer sleeve, an inner sleeve installed coaxially with the outer sleeve, a tubular test piece assembled at the outlet end of the outer sleeve, a top end cover for fixing the tubular test piece, a thermocouple passing through the inner sleeve, and a gas path; a gap is left between the inner tube wall of the outer sleeve and the outer tube wall of the inner sleeve; The outlet end of the inner sleeve is at the same end as the outlet end of the outer sleeve and is located inside the outer sleeve; the inlet end of the inner sleeve is at the same end as the inlet end of the outer sleeve and is located outside the outer sleeve; the inlet end of the inner sleeve is provided with a groove for installing a thermocouple; the inner sleeve is provided with a cooling gas inlet with an opening and closing valve; The inlet end of the outer sleeve is sealed with the outer tube wall of the inner sleeve, so that a sealed passage for gas circulation is formed between the inner tube wall of the outer sleeve and the outer tube wall of the inner sleeve; a heated gas outlet with an opening and closing valve is provided on the outer sleeve; The thermocouple is connected to the thermocouple display and is fixed in the groove at the inlet end of the inner sleeve by a clamp. The temperature measuring end of the thermocouple passes through the tubular test piece and abuts against the top end cover. The connection mode between the tubular test piece and the outlet end of the outer sleeve is flange connection. The outlet end of the outer sleeve is welded with a first flange, and the first flange is bolted to the top end cover fixing the tubular test piece; the top end cover includes a split clamp flange and a split clamp flange end cover; the tubular test piece is installed between the split clamp flange and the split clamp flange end cover, and is coaxial with the outer sleeve; the first flange, the split clamp flange and the split clamp flange end cover are connected by positioning bolts; The gas path includes a cooling gas inlet pipe and a heated gas outlet pipe; one end of the cooling gas inlet pipe is connected to the cooling gas inlet on the inner sleeve, and the other end is connected to the compressed air source; one end of the heated gas outlet pipe is connected to the heated gas outlet on the outer sleeve, and the other end is a free end; The probe device also includes a furnace wall outer surface flange and an outer sleeve flange fixed on the outer tube wall of the outer sleeve, and the outer sleeve flange is fixed to the furnace wall through the furnace wall outer surface flange.

2. A probe device for testing the high temperature corrosion resistance of metal materials on the heating surface of a waste incineration boiler according to claim 1, characterized in that: A rubber gasket is provided on the contact surface between the top end cover and the tubular test piece.

3. A method for testing the high temperature corrosion resistance of metal materials on the heating surface of a waste incineration boiler using the probe device described in claim 1, characterized in that: The following steps are involved: 1) Select the metal material to be tested and make a tubular test piece; 2) Fix the tubular test piece to the outlet end of the outer casing through the top end cover so that the tubular test piece is coaxial with the outer casing; 3) Drill a hole in the furnace wall and install the flange on the outer surface of the furnace wall on the outer wall at the hole; 4) Insert the probe device with the tubular test piece installed into the furnace through the opening of the furnace wall, adjust the insertion depth and angle, so that the position of the tubular test piece is completely exposed to the flue gas in the furnace, and install it at 90° to the flue gas flow; lock the outer sleeve flange on the outer sleeve, and assemble and fix it to the flange on the outer surface of the furnace wall; 5) Open the heated gas outlet valve and the cooling gas inlet valve, and introduce compressed air. The cooling gas enters the inner casing from the cooling gas inlet, and then enters the sealed passage for gas circulation between the inner tube wall of the outer casing and the outer tube wall of the inner casing after reaching the outlet end of the inner casing, and then is discharged from the heated gas outlet on the outer casing; 6) Observe the temperature of the tubular specimen displayed on the thermocouple display, adjust the opening of the cooling gas inlet valve until the required temperature is reached, and start the test; 7) After the time required for the test is reached, remove the outer sleeve flange, take out the probe device from the furnace wall, remove the tubular test piece from the top end cover, and observe the corrosion condition of the test piece surface; when the next test is required, only the test piece needs to be replaced.

4. The method for testing the high temperature corrosion resistance of the metal material of the heating surface of a waste incineration boiler according to claim 3 is characterized in that: The tubular test piece is connected to the outer sleeve outlet end by flange connection. The outer sleeve outlet end is welded with a first flange, and the first flange is bolted to the top end cover fixing the tubular test piece.

5. The method for testing the high temperature corrosion resistance of the metal material of the heating surface of a waste incineration boiler according to claim 3 is characterized in that: The top end cover includes a split clamp flange and a split clamp flange end cover; the tubular test piece is installed between the split clamp flange and the split clamp flange end cover; the first flange, the split clamp flange and the split clamp flange end cover are connected by positioning bolts.

6. The method for testing the high temperature corrosion resistance of the metal material of the heating surface of a waste incineration boiler according to claim 3 is characterized in that: When the tubular test piece is installed, a rubber gasket is provided on the contact surface between the tubular test piece and the top end cover.

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