Method and device for testing melting point of fly ash

Abstract

The invention discloses a fly ash melting point testing method and device, the testing device comprises a fly ash heating mechanism and a resistance testing mechanism, the resistance testing mechanism comprises a pair of high-temperature-resistant electrodes isolated from each other, and each high-temperature-resistant electrode comprises a wire sleeve; the electrode supporting piece is arranged at one end of the wire sleeve, and the electrode supporting piece extends in the axial direction of the wire sleeve; an electrode sheet disposed on the electrode support sheet; one end of the electrode wire is connected with the electrode plate, and the other end penetrates through the wire sleeve; wherein the electrode plate is inserted into a fly ash sample during testing. The melting point of the fly ash is measured based on the change of the resistance value of the fly ash at high temperature, the method has the characteristics of high precision and good reproducibility, the high-temperature-resistant electrode can be applied to the condition of 1500 DEG C or above, the high-temperature-resistant electrode can be rapidly separated from a molten fly ash sample after the test is finished, the test can be cyclically carried out under the condition that the electrode is not replaced, and the test efficiency is high. The continuous online test of the fly ash sample is facilitated.

Description

Technical Field

[0001] This application belongs to the technical field of boiler slagging warning, and specifically relates to a method and device for testing the melting point of fly ash. Background Art

[0002] China's resource conditions determine that coal-fired power generation will still play a role in ensuring power supply for a long time in the future. Affected by coal occurrence conditions, coal transportation capacity, and operating costs, there are problems such as complex coal types and poor coal quality in thermal coal, and it has become normal for coal-fired units to use coal deviating from the designed coal type. At the same time, along with the variable slagging characteristics of blended coal, it brings uncertain factors of heating surface slagging to coal-fired boilers. The slagging situation of coal-fired boilers is becoming increasingly prominent, which not only reduces the thermal efficiency of coal-fired boilers but also poses great potential safety hazards.

[0003] The essence of boiler slagging is the melting or partial melting of coal ash, which solidifies again when encountering the water-cooled wall. The factors affecting boiler slagging include coal ash melting point, boiler design, and coal-fired working conditions, etc. Among them, coal ash melting point and coal-fired working conditions are the main factors. Therefore, it is very necessary to accurately measure the coal ash melting point for preventing boiler coking. In the prior art, the ash cone method is generally used to measure the coal ash melting point. The ash cone method evaluates the melting characteristics of coal by observing the morphological changes of the triangular cone made of coal ash at high temperature, which has problems such as long test cycle and low accuracy, and there is a lag in warning boiler coking, and it has no guiding significance for the safe operation of boilers. Compared with the ash cone method, the resistance method measurement method has the characteristics of good reproducibility and high accuracy. However, due to the too high melting point of coal ash, reaching above 1000 °C, conventional electrodes cannot work stably at this temperature, resulting in difficulty in realizing the resistance method measurement of coal ash melting point. Summary of the Invention

[0004] The purpose of this application is to provide a method and device for testing the melting point of fly ash to solve the technical problems existing in the prior art, such as using the ash cone method to measure the coal ash melting point, having a long test cycle, low accuracy, having a lag in warning boiler coking, and having no guiding significance for the safe operation of boilers.

[0005] To achieve the above purpose, the first aspect of this application provides a device for testing the melting point of fly ash, including a fly ash heating mechanism and a resistance testing mechanism. The fly ash heating mechanism is used to heat the fly ash sample, and the resistance testing mechanism is used to test the real-time resistance during the heating process of the fly ash sample. The resistance testing mechanism includes a pair of mutually isolated high-temperature resistant electrodes, and the high-temperature resistant electrodes include:

[0006] Wire sleeve;

[0007] Electrode support piece, arranged at one end of the wire sleeve, and the electrode support piece extends along the axial direction of the wire sleeve;

[0008] An electrode sheet, disposed on the electrode support sheet;

[0009] An electrode wire, one end of which is connected to the electrode sheet and the other end of which is disposed through the wire sleeve;

[0010] Wherein, during testing, the electrode sheet is inserted into the fly ash sample.

[0011] In one or more embodiments, the wire sleeve is a single-hole corundum tube, the electrode support sheet is a corundum sheet, the electrode sheet is a platinum sheet, and the electrode sheet is pasted or wrapped on the electrode support sheet.

[0012] In one or more embodiments, the resistance testing mechanism further includes a power supply, a standard resistor, and a voltmeter. Both ends of the power supply are respectively connected to a pair of the high-temperature resistant electrodes. The standard resistor is disposed on the connection path between one of the high-temperature resistant electrodes and the power supply. The voltmeter is used to measure the voltage division of the standard resistor.

[0013] In one or more embodiments, the power supply is a DC power supply with a voltage of 1 - 30V, and the resistance of the standard resistor is 200 - 10MΩ.

[0014] In one or more embodiments, the fly ash heating mechanism includes a high-temperature furnace and a crucible. The high-temperature furnace includes a sample inlet and an electrode inlet. The crucible is used to hold the fly ash sample, and the crucible is inserted into the interior of the high-temperature furnace through the sample inlet. The pair of high-temperature resistant electrodes are inserted into the interior of the high-temperature furnace through the electrode inlet.

[0015] In one or more embodiments, the thickness of the fly ash sample loaded into the crucible is 5 - 30mm, and the depth of insertion of the high-temperature resistant electrodes into the fly ash sample during testing is 2 - 30mm.

[0016] In one or more embodiments, the fly ash heating mechanism further includes a moving unit, and the moving unit is used to drive the crucible to move so as to place the crucible into or take out of the high-temperature furnace.

[0017] In one or more embodiments, the resistance testing mechanism further includes an electrode fixing plate, and the electrode fixing plate is sleeved outside the wire sleeves of a pair of the high-temperature resistant electrodes to define the distance between the pair of high-temperature resistant electrodes.

[0018] To achieve the above object, a second aspect of the present application provides a method for testing the melting point of fly ash. Using the testing device described in any of the above embodiments, the testing method includes:

[0019] Controlling a pair of the high-temperature resistant electrodes to be inserted into the fly ash sample;

[0020] Control the fly ash heating mechanism to continuously heat the fly ash sample until the maximum temperature is reached. During the heating process, test the resistance change of the fly ash sample through the resistance testing mechanism to obtain test data;

[0021] Based on the test data, obtain the temperature value when the resistance change of the fly ash sample is the largest, and use it as the fly ash melting point.

[0022] In one or more embodiments, the fly ash heating mechanism includes a high-temperature furnace, a crucible, and a moving unit. The high-temperature furnace includes a sample inlet and an electrode inlet. The crucible is used to hold the fly ash sample, and the crucible is inserted into the high-temperature furnace through the sample inlet. The pair of high-temperature resistant electrodes are inserted into the high-temperature furnace through the electrode inlet, and the moving unit is used to drive the crucible to move;

[0023] The resistance testing mechanism further includes a power supply, a standard resistor, and a voltmeter. Both ends of the power supply are respectively connected to a pair of the high-temperature resistant electrodes. The standard resistor is arranged on the connection path between one of the high-temperature resistant electrodes and the power supply, and the voltmeter is used to measure the voltage division of the standard resistor;

[0024] The step of controlling the insertion of the pair of high-temperature resistant electrodes into the fly ash sample specifically is:

[0025] Add the fly ash sample into the crucible, and through the moving unit, place the crucible into the high-temperature furnace until a pair of the high-temperature resistant electrodes are inserted into the fly ash sample;

[0026] The step of controlling the fly ash heating mechanism to continuously heat the fly ash sample until the maximum temperature is reached. During the heating process, test the resistance change of the fly ash sample through the resistance testing mechanism to obtain test data specifically is:

[0027] Control the high-temperature furnace to heat the fly ash sample at a set constant heating rate. During the heating process, record the readings of the voltmeter at set time intervals to obtain the voltage readings at different time points. After reaching the maximum temperature, control the movement of the crucible through the moving unit until the fly ash sample is separated from the high-temperature resistant electrodes;

[0028] The step of obtaining the temperature value when the resistance change of the fly ash sample is the largest based on the test data and using it as the fly ash melting point specifically is:

[0029] Calculate the voltage drop between each time point and the next time point, as well as the temperature values corresponding to each time point, to obtain the correlation data between the temperature values and the voltage drops. Select the temperature value corresponding to the largest voltage drop from the correlation data as the fly ash melting point.

[0030] Different from the prior art, the beneficial effects of this application are:

[0031] This application determines the melting point of fly ash based on the change in the resistance value of fly ash at high temperatures, featuring high precision and good reproducibility. It can obtain the melting point temperature information in the early stage of fly ash melting, which has advantages in further determining the slagging risk of fly ash.

[0032] The high-temperature resistant electrode provided by this application includes a wire support tube and an electrode support sheet, and can be applied under conditions above 1500°C. The electrode sheet provides sufficient contact area with the fly ash powder, ensuring the test accuracy.

[0033] The high-temperature resistant electrode adopted by this application can be quickly separated from the molten fly ash sample after the test. Without replacing the electrode, cyclic tests can be carried out, which is helpful for the continuous on-line testing of fly ash samples. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments recorded in this application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0035] Figure 1 It is a schematic structural diagram of an embodiment of the fly ash melting point test device of this application;

[0036] Figure 2 It is a schematic flow diagram of an embodiment of the fly ash melting point test method of this application;

[0037] Figure 3 It is a correlation data diagram of the voltage drop and temperature values of various samples in the embodiments of this application;

[0038] Figure 4 It is an SEM image of various samples after heating in the embodiments of this application.

[0039] As shown in the figure:

[0040] Resistance test mechanism 100; high-temperature resistant electrode 101; wire sleeve 1011; electrode support sheet 1012; electrode sheet 1013; electrode wire 1014; power supply 102; standard resistor 103; voltmeter 104; electrode fixing plate 105;

[0041] Fly ash heating mechanism 200; high-temperature furnace 201; sample inlet 2011; electrode inlet 2012; crucible 202; moving unit 203. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0042] To enable those skilled in the art to better understand the technical solutions in this application, the following will clearly and completely describe the technical solutions in the embodiments of this application in conjunction with the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of this application.

[0043] To solve the problems of long test cycle and low accuracy existing in the grey cone method in the prior art, the applicant has developed a test device for the melting point of fly ash. This test device can meet the test requirements for the melting point of fly ash exceeding 1000 °C, can measure the melting point of fly ash samples by the resistance method, and has the characteristics of good reproducibility and high accuracy.

[0044] Specifically, please refer to Figure 1 , Figure 1 which is a schematic structural diagram of an embodiment of the test device for the melting point of fly ash in this application.

[0045] As Figure 1 shown, the test device includes a fly ash heating mechanism 200 and a resistance testing mechanism 100. Among them, the fly ash heating mechanism 200 is used to heat the fly ash sample, and the resistance testing mechanism 100 is used to test the real-time resistance of the fly ash sample during the heating process.

[0046] Specifically, the resistance testing mechanism 100 includes a pair of mutually isolated high-temperature-resistant electrodes 101. The high-temperature-resistant electrodes 101 include a wire sleeve 1011, an electrode support piece 1012, an electrode piece 1013, and an electrode wire 1014.

[0047] Among them, the electrode support piece 1012 is arranged at one end of the wire sleeve 1011 and extends along the axial direction of the wire sleeve 1011. The electrode piece 1013 is arranged on the electrode support piece 1012. One end of the electrode wire 1014 is connected to the electrode piece 1013, and the other end passes through the wire sleeve 1011. During the test, the electrode piece 1013 is inserted into the fly ash sample to realize the resistance measurement of the fly ash sample.

[0048] In one embodiment, the wire sleeve 1011 can be a single-hole corundum tube, and the electrode support piece 1012 can be a corundum sheet.

[0049] In one embodiment, the electrode piece 1013 can be a platinum sheet electrode, and the electrode wire 1014 can be a platinum wire electrode.

[0050] Based on the above solution, the wire sleeve 1011 sleeved outside the electrode wire 1014 can significantly improve the high-temperature resistance performance of the electrode wire 1014, enabling it to be applied in an environment above 1000°C to meet the test requirements for the melting point of fly ash. Through the setting of the electrode support piece 1012, the problem that the platinum sheet electrode softens at high temperatures and cannot be separated from the fly ash is avoided, enabling it to be inserted into the fly ash sample in an environment above 1000°C and quickly separated from the fly ash sample after the test. It can perform cyclic tests without replacing the electrode, which is helpful for the continuous on-line test of the fly ash melting point.

[0051] In one embodiment, the electrode support piece 1012 can be fixed by mortise and tenon joint or bonding.

[0052] In one embodiment, the electrode piece 1013 can be fixed by pasting on the electrode support piece 1012 or wrapping around the electrode support piece 1012.

[0053] In one embodiment, an electrode support piece 1012 can be arranged at the end of the wire sleeve 1011. In other embodiments, multiple electrode support pieces 1012 can also be arranged, such as two. The two electrode support pieces 1012 can also cooperate to clamp the electrode piece 1013, and all can achieve the effects of this embodiment.

[0054] The resistance test mechanism 100 further includes a power supply 102, a standard resistor 103, and a voltmeter 104. Both ends of the power supply 102 are respectively connected to a pair of high-temperature-resistant electrodes 101. The standard resistor 103 is arranged on the connection path between one high-temperature-resistant electrode 101 and the power supply 102. The voltmeter 104 is used to measure the voltage division across the standard resistor 103.

[0055] It can be understood that by measuring the voltage division of the standard electrode with the voltmeter 104, the current test of the circuit can be realized, and the change in the current can characterize the change in the resistance of the fly ash sample.

[0056] In one embodiment, the power supply 102 can be a DC power supply 102, its voltage can be 1 - 30V, and the resistance of the standard resistor 103 can be 200Ω - 10MΩ.

[0057] It should be noted that in this embodiment, the two high-temperature-resistant electrodes 101 need to be ensured to be isolated from each other, and their wire sleeves 1011 must be separated from each other. Therefore, it is impossible to use a double-hole corundum tube to simultaneously achieve the high-temperature protection of the electrode wires 1014 of the two high-temperature-resistant electrodes 101 to avoid the occurrence of a short circuit due to the conduction of corundum at high temperatures.

[0058] In addition, to further ensure the mutual isolation of the two high-temperature resistant electrodes 101, the resistance testing mechanism 100 further includes an electrode fixing plate 105, which is sleeved outside the wire sleeves 1011 of a pair of high-temperature resistant electrodes 101 to limit the distance between the pair of high-temperature resistant electrodes 101.

[0059] In this embodiment, the fly ash heating mechanism 200 includes a high-temperature furnace 201 and a crucible 202. The high-temperature furnace 201 includes a sample inlet 2011 and an electrode inlet 2012. The crucible 202 is used to hold the fly ash sample, and the crucible 202 is inserted into the interior of the high-temperature furnace 201 through the sample inlet 2011, and a pair of high-temperature resistant electrodes 101 are inserted into the interior of the high-temperature furnace 201 through the electrode inlet 2012.

[0060] Among them, the high-temperature furnace 201 can be a vertical high-temperature furnace with openings at both ends. Its inner cavity can have a constant temperature zone of more than 10 cm. It has a programmable temperature rising function, and the maximum temperature that can be heated can reach 1700 °C. The crucible 202 can enter the inner cavity through the sample inlet 2011 at the bottom of the high-temperature furnace 201 and is located in the constant temperature zone; the high-temperature resistant electrodes 101 can be inserted into the inner cavity through the electrode inlet 2012 at the top and are located in the constant temperature zone so that they can be inserted into the fly ash sample in the crucible 202.

[0061] In this embodiment, to facilitate the feeding and discharging of the fly ash sample, the fly ash heating mechanism 200 further includes a moving unit 203, which is used to drive the crucible 202 to move so as to put the crucible 202 into or take it out of the high-temperature furnace 201.

[0062] Among them, the moving unit 203 can be a lifting drive mechanism commonly used in the art, and all can achieve the effects of this embodiment.

[0063] In one embodiment, to ensure the test effect, the thickness of the fly ash sample loaded into the crucible 202 can be 5 - 30 mm. During the test, the depth of the high-temperature resistant electrodes 101 inserted into the fly ash sample can be 2 - 30 mm.

[0064] This application also provides a method for testing the melting point of fly ash. This testing method is carried out using the testing device of any of the above embodiments. Specifically, please refer to Figure 2 , Figure 2 which is a schematic flow chart of an embodiment of the method for testing the melting point of fly ash in this application.

[0065] As Figure 2 shown, this testing method includes:

[0066] S100. Control a pair of high-temperature resistant electrodes to insert into the fly ash sample.

[0067] In one embodiment, the method for controlling the high-temperature resistant electrodes to insert into the fly ash sample can be:

[0068] Add the fly ash sample into a crucible, and control the moving unit to place the crucible inside the high-temperature furnace until a pair of high-temperature resistant electrodes are inserted into the fly ash sample.

[0069] S200. Control the fly ash heating mechanism to continuously heat the fly ash sample until the maximum temperature is reached. During the heating process, test the resistance change of the fly ash sample through the resistance testing mechanism to obtain test data.

[0070] In one embodiment, the method for obtaining the test data can be:

[0071] Control the high-temperature furnace to heat the fly ash sample at a set constant heating rate. During the heating process, record the readings of the voltmeter at set time intervals to obtain the voltage readings at different time points. After reaching the maximum temperature, control the movement of the crucible through the moving unit until the fly ash sample is separated from the high-temperature resistant electrodes.

[0072] Based on the above scheme, the test data is the voltage readings of the standard resistance at different time points, and the voltage division of the standard resistance can characterize the resistance value of the fly ash sample.

[0073] S300. Based on the test data, obtain the temperature value at which the resistance change of the fly ash sample is the largest as the melting point of the fly ash.

[0074] In one embodiment, when the test data is the voltage readings of the standard resistance at different time points, the method for analyzing the test data can be:

[0075] Calculate the voltage drop between each time point and the previous time point, as well as the temperature values corresponding to each time point, to obtain the correlation data between the temperature values and the voltage drops. Select the temperature value corresponding to the maximum voltage drop from the correlation data as the melting point of the fly ash.

[0076] It can be understood that the high-temperature furnace heats up at a constant rate. Therefore, the corresponding temperature can be calculated based on time, so as to obtain the temperature point C corresponding to each time point 1 , C 2 , C 3 , C 4 , C 5 …….

[0077] Through the voltmeter, the voltmeter reading corresponding to each time point can be obtained as V 1 , V 2 , V 3 , V 4 , V 5 …….

[0078] Calculate the voltage drop between each time point and the previous time point: ΔV n = V n+1 – V n , and obtain ΔV1 、 ΔV 2 、 ΔV 3 、 ΔV 4 、 ΔV 5 …。

[0079] By comparison, the maximum value of ΔVmax is obtained, and the corresponding temperature point is the fly ash melting point T f 。

[0080] The beneficial effects of the technical solution of the present application will be further elaborated in detail below in conjunction with specific embodiments.

[0081] Embodiment:

[0082] Collect fly ash during the operation of different boilers as samples to obtain Samples 1, 2, and 3, and use the Figure 1 shown test device to test the fly ash melting point of the samples. The specific test method includes:

[0083] Put the fly ash sample into the crucible, place the crucible in the constant temperature zone at the center of the high-temperature furnace through the moving unit, and insert the high-temperature resistant electrode into the fly ash sample; control the high-temperature furnace to heat the fly ash sample at a constant heating rate until the termination temperature is reached, and read the voltage value of the voltmeter at preset time intervals during the heating process; after heating is completed, lower the crucible by a certain height through the moving unit to separate the fly ash sample from the high-temperature resistant electrode, and let the high-temperature furnace and the fly ash sample cool naturally. After the furnace body cools, take out the crucible from the high-temperature furnace through the moving unit.

[0084] Based on the heating rate, calculate the temperature value corresponding to each time point, and at the same time calculate the voltage drop between each time point and the next time point to obtain the correlation data of the voltage drop and the temperature value. Select the temperature value corresponding to the maximum voltage drop as the fly ash melting point.

[0085] The test parameters of Samples 1, 2, and 3 are shown in the following table:

[0086]

[0087]

[0088] The correlation data of the voltage drop and the temperature value of Samples 1, 2, and 3 are as Figure 3 shown, Figure 3 which is the correlation data diagram of the voltage drop and the temperature value of each sample in the embodiment of the present application.

[0089] As Figure 3 shown, select the temperature values corresponding to the maximum voltage drop of Samples 1, 2, and 3 as the fly ash melting points respectively, and the fly ash melting points of Samples 1, 2, and 3 are 960 °C, 750 °C, and 1170 °C respectively.

[0090] Effect example:

[0091] Samples 1, 2, and 3 were heated to 1000 °C, 800 °C, and 1200 °C respectively, and characterization analysis was carried out to obtain Figure 4 , Figure 4 which are the SEM images of each sample after heating in the embodiments of the present application.

[0092] As Figure 4 shown, when sample 1 was at 1000 °C, sample 2 was at 800 °C, and sample 3 was at 1200 °C, all showed a partially molten state, which was consistent with the test results.

[0093] For those skilled in the art, it is obvious that the present application is not limited to the details of the above exemplary embodiments, and without departing from the spirit or basic characteristics of the present application, the present application can be implemented in other specific forms. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present application is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present application. Any reference signs in the claims should not be construed as limiting the claimed rights.

[0094] In addition, it should be understood that although this specification is described according to embodiments, not every embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A test device for the melting point of fly ash, characterized in that: The invention comprises a fly ash heating mechanism and a resistance testing mechanism, wherein the fly ash heating mechanism is used to heat the fly ash sample, and the resistance testing mechanism is used to test the real-time resistance of the fly ash sample during heating. The resistance testing mechanism comprises a pair of mutually isolated high-temperature resistant electrodes, and the high-temperature resistant electrodes comprise: Wire sleeve; An electrode support sheet is arranged at one end of the wire sleeve, and the electrode support sheet is extended along the axial direction of the wire sleeve; An electrode sheet, arranged on the electrode support sheet; An electrode wire, one end of which is connected to the electrode sheet and the other end of which is passed through the wire sleeve; Wherein, during the test, the electrode sheet is inserted into the fly ash sample.

2. The testing device according to claim 1, characterized in that: The wire sleeve is a single-hole corundum tube, the electrode support sheet is a corundum sheet, the electrode sheet is a platinum sheet, and the electrode sheet is pasted or wrapped on the electrode support sheet.

3. The testing device according to claim 1, characterized in that: The resistance testing mechanism also includes a power supply, a standard resistor and a voltmeter. The two ends of the power supply are respectively connected to a pair of the high temperature resistant electrodes. The standard resistor is arranged on a connection path between one of the high temperature resistant electrodes and the power supply. The voltmeter is used to measure the divided voltage of the standard resistor.

4. The testing device according to claim 3, characterized in that: The power supply is a direct current power supply with a voltage of 1 to 30 V, and the resistance of the standard resistor is 200 to 10 MΩ.

5. The testing device according to claim 1, characterized in that: The fly ash heating mechanism includes a high-temperature furnace and a crucible. The high-temperature furnace includes a sample inlet and an electrode inlet. The crucible is used to hold the fly ash sample, and the crucible is inserted into the high-temperature furnace through the sample inlet. The pair of high-temperature resistant electrodes are inserted into the high-temperature furnace through the electrode inlet.

6. The testing device according to claim 5, characterized in that: The thickness of the fly ash sample loaded into the crucible is 5 to 30 mm, and the depth of the high temperature resistant electrode inserted into the fly ash sample during testing is 2 to 30 mm.

7. The testing device according to claim 5, characterized in that: The fly ash heating mechanism further includes a moving unit, which is used to drive the crucible to move so as to put the crucible into or take it out of the high-temperature furnace.

8. The testing device according to claim 1, characterized in that: The resistance testing mechanism further includes an electrode fixing plate, which is sleeved outside the wire sleeves of the pair of high temperature resistant electrodes to limit the distance between the pair of high temperature resistant electrodes.

9. A method for testing the melting point of fly ash, characterized in that: Using the testing device according to any one of claims 1 to 8, the testing method comprises: Controlling a pair of high temperature resistant electrodes to be inserted into the fly ash sample; Controlling the fly ash heating mechanism to continuously heat the fly ash sample until the maximum temperature is reached, and testing the resistance change of the fly ash sample by the resistance testing mechanism during the heating process to obtain test data; Based on the test data, the temperature value at which the resistance change of the fly ash sample is the largest is obtained as the melting point of the fly ash.

10. The testing method according to claim 9, characterized in that: The fly ash heating mechanism comprises a high temperature furnace, a crucible and a moving unit, the high temperature furnace comprises a sample inlet and an electrode inlet, the crucible is used to hold the fly ash sample, and the crucible is inserted into the high temperature furnace through the sample inlet, the pair of high temperature resistant electrodes are inserted into the high temperature furnace through the electrode inlet, and the moving unit is used to drive the crucible to move; The resistance testing mechanism further includes a power supply, a standard resistor and a voltmeter, wherein both ends of the power supply are respectively connected to a pair of the high temperature resistant electrodes, the standard resistor is arranged on a connection path between one of the high temperature resistant electrodes and the power supply, and the voltmeter is used to measure the divided voltage of the standard resistor; The step of controlling a pair of high temperature resistant electrodes to be inserted into the fly ash sample is specifically as follows: Adding a fly ash sample into the crucible, and placing the crucible into a high-temperature furnace by a moving unit until a pair of high-temperature resistant electrodes are inserted into the fly ash sample; The step of controlling the fly ash heating mechanism to continuously heat the fly ash sample until the maximum temperature is reached, and testing the resistance change of the fly ash sample by the resistance testing mechanism during the heating process to obtain the test data is specifically as follows: Controlling the high temperature furnace to heat the fly ash sample at a set constant heating rate, recording the readings of the voltmeter at set time intervals during the heating process to obtain voltage readings at different time points, and after reaching the maximum temperature, controlling the crucible to move through a moving unit until the fly ash sample is separated from the high temperature resistant electrode; The step of obtaining the temperature value at which the resistance change of the fly ash sample is the largest based on the test data as the melting point of the fly ash is specifically as follows: The voltage drop between each time point and the next time point, as well as the temperature value corresponding to each time point, are calculated to obtain correlation data of the temperature value and the voltage drop, and the temperature value corresponding to the maximum voltage drop is selected from the correlation data as the fly ash melting point.

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