Sensor for detecting dissolved C2H2 gas in power transformer oil

Abstract

The invention discloses a sensor for detecting C2H2 gas dissolved in power transformer oil, and belongs to the technical field of semiconductor gas sensors. The problem that an existing semiconductor C2H2 gas sensor cannot respond to C2H2 gas under the oxygen-free condition is solved. A base is a cube, a square through hole is formed in the center of the cube, and a supporting film, a heater, an isolation film, an interdigital electrode and a gas-sensitive material layer are attached to the surface, provided with the through hole, of the cube at a time; the centers of the gas sensitive material layer, the interdigital electrode, the isolation film, the heater and the supporting film correspond to the through hole of the cube; the isolation film is used for isolating electrical connection between the interdigital electrode and the heater, the gas-sensitive material layer is attached to the center of the upper surface of the interdigital electrode, and the resistance value of the gas-sensitive material layer changes along with the concentration of detected gas; and the gas sensitive material layer is prepared by doping SnO2 with In and Pt elements. The method is suitable for detecting the C2H2 gas dissolved in the power transformer oil.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor gas sensors. Background Art

[0002] With the rapid development of my country's power industry, the scale of the power system continues to expand. Power transformers are an indispensable core equipment in the power system. Transformer failure will affect the normal operation of the entire power system. The detection of dissolved gas components in transformer oil can achieve timely warning of transformer failures to avoid affecting the operation of the power system. 2 H 2 Gas is a typical characteristic gas dissolved in transformer oil. Its release in the transformer often means that the transformer has an overheating fault. Timely and effective detection of C 2 H 2 Gas is of great significance to the maintenance of transformer equipment operation safety. At present, most traditional gas-sensitive performance tests use dry air as the background gas. However, in the actual transformer detection application scenario, a series of pre-treatments are required before gas detection, including transformer oil sampling and purification, and degassing and separation of dissolved gas in the oil. The degassing process of dissolved gas from transformer oil requires vacuum treatment, and chromatographic column separation is required after vacuum degassing. In order to prevent the separation column from being oxidized at high temperature, nitrogen (N 2 ) as carrier gas. 2 H 2 The sensor requires oxygen to be activated on the surface and converted into active oxygen, which then reacts with C 2 H 2 reaction, generating corresponding electrical signals, and cannot react to C under anaerobic conditions 2 H 2 Gas response. Summary of the invention

[0003] The present invention is to solve the existing semiconductor C 2 H 2 Gas sensors cannot detect C in the absence of oxygen. 2 H 2 In order to solve the problem of gas response, a method for dissolving C in power transformer oil is provided. 2 H 2 Sensors for gas detection.

[0004] The invention discloses a method for dissolving C in power transformer oil. 2 H 2 A gas detection sensor, comprising: a gas sensitive material layer, interdigital electrodes, an isolation film, a heater, a support film and a base;

[0005] The base is a cube, a square through hole is opened in the center of the cube, and a support film, a heater, an isolation film, interdigital electrodes and a gas-sensitive material layer are attached to a surface of the cube with the through hole at the same time;

[0006] The centers of the gas-sensitive material layer, the interdigital electrodes, the isolation film, the heater and the support film all correspond to the through holes of the cube;

[0007] The isolation film is used to isolate the electrical connection between the interdigital electrodes and the heater.

[0008] The gas-sensitive material layer is attached to the center of the upper surface of the interdigital electrode, and the resistance of the gas-sensitive material layer changes with the concentration of the detected gas; the gas-sensitive material layer is made of SnO doped with In and Pt elements. 2 Made of;

[0009] By adjusting the input voltage of the heater, the heating temperature of the heater is adjusted;

[0010] The interdigital electrodes and the heater are connected to a measuring circuit via leads respectively.

[0011] Furthermore, in the present invention, the gas sensitive material layer is formed by sintering In and Pt elements at 600°C and doping them into SnO 2 Made of lattice.

[0012] Furthermore, in the present invention, the specific production process of the gas-sensitive material is as follows:

[0013] Step 1: Take 0.8g of SnCl 2 ·2H 2 O was added with 10 mL of ethanol solution, and then mixed with 10 mL of N,N-dimethylformamide solution, 4 g of polyvinyl pyrrolidone, and 1% mol H 2 PtCl 6 6H 2 O and 0.8% mol InCl 3 ·4H 2 O mixing for electrospinning to obtain a polymer mixture;

[0014] Step 2: The polymerized mixture is sintered at 600°C for 5 hours to allow In and Pt to be doped into SnO 2 lattice, obtaining 0.8%In-1%Pt-SnO 2 powder;

[0015] Step 3: 0.8% In-1% Pt-SnO 2 The powder was evenly dispersed in 5 mL of ethanol to obtain a gas-sensitive material.

[0016] Furthermore, in the present invention, the power supply voltage of the electrospinning is 20 kV, and the propulsion speed is 0.6 mL / h.

[0017] Furthermore, in the present invention, the gas-sensitive material is uniformly coated on the interdigital electrodes by a micro-dropping method.

[0018] Furthermore, in the present invention, the base adopts a silicon substrate.

[0019] Furthermore, in the present invention, the heater is made of gold, platinum or nickel.

[0020] The In / Pt doped SnO 2 C 2 H 2 Gas sensors, compared to existing C 2 H 2 The sensor is doped with metal elements In / Pt in SnO 2 More active sites and defects were introduced into the nanofibers, which significantly improved their sensitivity. 2 The crystal size of nanofibers is reduced, which increases their specific surface area and is beneficial for their bonding with C 2 H 2 The sensor has high response, fast response speed and excellent stability. The excellent performance shows that the sensor can quickly and accurately detect C in an oxygen-free environment. 2 H 2 Has broad prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a structural disassembly diagram of the sensor of the present invention;

[0022] Figure 2 This is a schematic diagram of the specific production process of gas-sensitive materials;

[0023] Figure 3 0.8% In-1% Pt-SnO in the embodiment 2 Transmission electron microscopy images of nanofibers;

[0024] Figure 4 For the samples in the examples, 5-50 ppm C 2 H 2 Response-recovery curve of

[0025] Figure 5 0.8% In-1% Pt-SnO in the embodiment 2 Sensor pair C 2 H 2 The relationship between the response value and gas concentration;

[0026] Figure 6 0.8% In-1% Pt-SnO in the embodiment 2 The sensor is tested under continuous dynamic cycle at 5ppm C 2 H 2 Response-recovery curve of

[0027] Figure 7 0.8% In-1% Pt-SnO in the embodiment 2 Sensor for 5ppm C 2 H 2 Response-recovery curve. DETAILED DESCRIPTION

[0028] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0029] Specific implementation method 1: refer to Figure 1 Specifically describe this embodiment, the method for dissolving C in power transformer oil described in this embodiment 2 H 2 Gas detection sensor, a kind of sensor for dissolving C in power transformer oil 2 H 2 A gas detection sensor comprises: a gas sensitive material layer 1, interdigital electrodes 2, an isolation film 3, a heater 4, a support film 5 and a base 6;

[0030] The base is a cube, a square through hole is opened in the center of the cube, and a support film 5, a heater 4, an isolation film 3, interdigital electrodes 2 and a gas-sensitive material layer 1 are attached to a surface of the cube with the through hole.

[0031] The centers of the gas-sensitive material layer 1, the interdigital electrodes 2, the isolation film 3, the heater 4 and the support film 5 all correspond to the through holes of the cube;

[0032] The isolation film 3 is used to isolate the electrical connection between the interdigital electrodes 2 and the heater 4.

[0033] The gas-sensitive material layer 1 is attached to the center of the upper surface of the interdigital electrode 2. The resistance of the gas-sensitive material layer 1 varies with the concentration of the detected gas. The gas-sensitive material layer 1 is made of SnO doped with In and Pt elements. 2 Made of;

[0034] By adjusting the input voltage of the heater 4, the heating temperature of the heater 4 is adjusted;

[0035] The interdigital electrodes 2 and the heater 4 are connected to a measuring circuit via leads, respectively.

[0036] Furthermore, in the present invention, the gas sensitive material layer is formed by sintering In and Pt elements at 600°C and doping them into SnO 2 Made of lattice.

[0037] Furthermore, in this embodiment, the specific production process of the gas-sensitive material is as follows:

[0038] Step 1: Take 0.8g of SnCl 2 ·2H 2 O was added with 10 mL of ethanol solution, and then mixed with 10 mL of N,N-dimethylformamide (DMF) solution, 4 g of polyvinylpyrrolidone (PVP), 1% molH 2 PtCl 6 6H 2 O and 0.8% mol InCl 3 ·4H 2 O mixing for electrospinning to obtain a polymer mixture;

[0039] Step 2: The polymerized mixture is sintered at 600°C for 5 hours to allow In and Pt to be doped into SnO 2 lattice, obtaining 0.8%In-1%Pt-SnO 2 powder;

[0040] Step 3: 0.8% In-1% Pt-SnO 2 The powder was evenly dispersed in 5 mL of ethanol to obtain a gas-sensitive material.

[0041] Furthermore, in this embodiment, the power supply voltage of the electrospinning is 20 kV, and the propulsion speed is 0.6 mL / h.

[0042] Furthermore, in this embodiment, the gas-sensitive material is uniformly coated on the interdigital electrodes by a micro-dropping method.

[0043] Furthermore, in this embodiment, the base 6 is made of a silicon substrate.

[0044] Furthermore, in this embodiment, the heater 4 is made of gold, platinum or nickel. Specific embodiment: Mixing of raw materials. Take 0.8g of commercial SnCl 2 ·2H 2 O, add 10 mL ethanol, 10 mL N, N-dimethylformamide (DMF), 4 g polyvinylpyrrolidone (PVP) and 0.8% mol InCl 3 ·4H2 O, set the power supply voltage to 20 kV and the propulsion speed to 0.6 mL / h for electrospinning.

[0045] 0.8%In-SnO 2 The electrospinning mixture was sintered at 600 °C for 5 h to allow In to be doped into SnO 2 Lattice.

[0046] Preparation of electrode sheet. 0.8% In-SnO 2 The powder is evenly dispersed in an ethanol solution, evenly coated on an electrode sheet using a micro-dropping method, and dried at room temperature.

[0047] Device welding. The obtained electrode sheet is welded to the hexagonal base using a spot welding device to obtain a 0.8% In-SnO 2 sensor device.

[0048] The prepared device was subjected to C 2 H 2 Gas sensing performance test shows that it is sensitive to 5ppm C at 200℃ 2 H 2 The response value is 0.7.

[0049] Figure 2 Schematic diagram of the experimental process of the embodiment. Figure 3 0.8% In-1% Pt-SnO in the embodiment 2 Transmission electron microscopy image of nanofibers. It can be seen from the figure that 0.8% In-1% Pt-SnO 2 The grain size is small, the grains are loosely stacked, there are tiny holes on the surface, and the internal space of the hollow structure is well developed. Figure 4 The 0.8% In-1% Pt-SnO 2 Sensors for 5, 10, 20, 30, 40, 50 ppm C 2 H 2 The response-recovery curve of the gas can be calculated to obtain its response to 5, 10, 20, 30, 40, and 50 ppm C at 200°C. 2 H 2 The gas response values ​​are 0.7, 7.2, 8.9, 10.0, 10.6, and 11.1, respectively. Figure 5 0.8% In-1% Pt-SnO in the embodiment 2 The response value of the sensor is related to C 2 H 2 The relationship between gas concentration (5-50ppm) and the fitting curve shows that as C 2 H 2With the increasing gas concentration, 0.8%In-1%Pt-SnO 2 Sensor pair C 2 H 2 The response value increases accordingly, and its effect on C 2 H 2 The growth rate of the gas response value continues to decrease, and the fitting curve eventually tends to be flat. Figure 6 The example shows 0.8%In-1%Pt-SnO 2 Sensor for 5ppm C 2 H 2 The response and recovery time of 0.8%In-1%Pt-SnO 2 Sensor for 5ppm C 2 H 2 The response time of the gas was 190s and the recovery time was 427s. Figure 7 0.8% In-1% Pt-SnO in the embodiment 2 The sensor is tested under continuous dynamic cycle at 5ppm C 2 H 2 The response-recovery curve of 5ppm C 2 H 2 The response value did not show obvious attenuation, the baseline was relatively stable, and the response recovery time hardly changed, showing strong stability and repeatability.

[0050] Since traditional MOS sensors are based on the oxygen depletion layer mechanism, oxygen is required to adsorb electrons on the surface of the gas-sensitive material, consume a part of the electrons on the surface of the material, and then release the electrons back to the MOS material through the reaction of oxygen ions adsorbed on the surface and gas, thereby forming an electrical signal response. However, in the detection environment of gas in transformer oil, the present invention usually requires a chromatographic column to separate the gas in advance during detection, and the carrier gas required for the chromatographic column to separate the gas is nitrogen, so there is no oxygen in the entire system. Therefore, the existing sensors cannot be implemented under anaerobic conditions. The sensor of the present invention can respond quickly to acetylene gas under anaerobic conditions, and the detection accuracy is significantly improved.

[0051] Compared with the prior art, the positive effect of the present invention is that it realizes the 2 H 2 It has excellent gas-sensing properties; at the same time, the preparation method is simple, the material source is simple and low-priced, the sensor performance is stable and the response is rapid.

[0052] Although the present invention is described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the present invention. It should therefore be understood that many modifications may be made to the exemplary embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that the various dependent claims and features described herein may be combined in a manner different from that described in the original claims. It should also be understood that the features described in conjunction with a single embodiment may be used in other described embodiments.

Claims

1. A sensor for detecting dissolved C2H2 gas in power transformer oil, characterized in that: include: A gas-sensitive material layer (1), interdigitated electrodes (2), an isolation film (3), a heater (4), a support film (5) and a base (6); The base is a cube, a square through hole is opened at the center of the cube, and a support film (5), a heater (4), an isolation film (3), interdigital electrodes (2) and a gas-sensitive material layer (1) are attached to a surface of the cube with the through hole at the same time; The centers of the gas-sensitive material layer (1), the interdigitated electrodes (2), the isolation film (3), the heater (4) and the support film (5) all correspond to the through holes of the cube; The isolation film (3) is used to isolate the electrical connection between the interdigital electrodes (2) and the heater (4). The gas-sensitive material layer (1) is attached to the center of the upper surface of the interdigital electrode (2), and the resistance of the gas-sensitive material layer (1) changes with the concentration of the detected gas; the gas-sensitive material layer (1) is made of SnO2 doped with In and Pt elements; The heating temperature of the heater (4) is adjusted by adjusting the input voltage of the heater (4); The interdigital electrodes (2) and the heater (4) are respectively connected to a measuring circuit via leads.

2. A sensor for detecting dissolved C2H2 gas in power transformer oil according to claim 1, characterized in that: The gas-sensitive material layer is made of In and Pt elements doped into the SnO2 lattice by sintering at 600°C.

3. A sensor for detecting dissolved C2H2 gas in power transformer oil according to claim 1, characterized in that: The specific production process of gas-sensitive materials is as follows: Step 1: 0.8 g of SnCl2·2H2O was added to 10 mL of ethanol solution, and then mixed with 10 mL of N,N-dimethylformamide (DMF) solution, 4 g of polyvinylpyrrolidone (PVP), 1% mol H2PtCl6·6H2O and 0.8% mol InCl3·4H2O for electrospinning to obtain a polymer mixture; Step 2: Sintering the polymerized mixture at 600° C. for 5 hours to allow In and Pt to be doped into the SnO2 lattice to obtain 0.8% In-1% Pt-SnO2 powder; Step 3: Evenly disperse 0.8% In-1% Pt-SnO2 powder in 5 mL of ethanol to obtain a gas-sensitive material.

4. A sensor for detecting dissolved C2H2 gas in power transformer oil according to claim 1 or 2, characterized in that: The power supply voltage of electrospinning was 20 kV, and the propulsion speed was 0.6 mL / h.

5. A sensor for detecting dissolved C2H2 gas in power transformer oil according to claim 1 or 2, characterized in that: The gas-sensitive material is uniformly coated on the interdigital electrodes by micro-dropping method.

6. A sensor for detecting dissolved C2H2 gas in power transformer oil according to claim 1, characterized in that: The base (6) is made of silicon.

7. A sensor for detecting dissolved C2H2 gas in power transformer oil according to claim 1, characterized in that: The heater (4) is made of gold, platinum or nickel.

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