DTS-based temperature monitoring device and method for small steel pipe in boiler top

Abstract

The invention discloses a DTS-based temperature monitoring device and method for small steel pipes in a boiler top, and relates to the technical field of boiler temperature monitoring. Multimode optical fibers of polyimide coating layers are arranged on each group of pipe rows in an S-shaped structure, and the same multimode optical fiber crosses one steel pipe every time the multimode optical fiber is bent; the four multimode optical fibers of each group of pipe rows are gathered into one pipeline and are fixed in the pipeline through the fixing buckles II so as to guide the multimode optical fibers to the outside of the furnace; the multimode optical fiber is connected with a multichannel Raman temperature measurement demodulator through a communication optical cable to form a distributed optical fiber temperature measurement system; through the steps of laser pulse emission, scattered light signal receiving and processing, data acquisition, analysis, alarm and the like, distributed, real-time and high-precision monitoring of the temperature of the small steel pipe in the boiler top large ladle is realized by using a multi-channel Raman temperature measurement demodulator, so that the safety and efficiency of boiler operation are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of boiler temperature monitoring, and in particular to a temperature monitoring device and method for small steel pipes in a boiler furnace top based on DTS. Background Art

[0002] The boiler roof ballast is a critical component in the boiler system. The temperature distribution of the small steel pipes within it directly impacts the boiler's operating efficiency and safety. Traditional temperature monitoring methods (such as thermocouples, ultrasound, X-ray, magnetic powder, and infrared temperature measurement) suffer from limited measurement points, large areas of missed detection, complex field deployment, electromagnetic crosstalk, and poor anti-interference capabilities. These factors make it difficult to meet the comprehensive temperature monitoring requirements of the small steel pipes within the boiler roof ballast. Therefore, this invention proposes a device and method for monitoring the temperature of small steel pipes within the boiler roof ballast based on DTS. Summary of the Invention

[0003] In order to solve the problems existing in the above-mentioned prior art, the present invention provides a temperature monitoring device and method for small steel pipes in the boiler furnace roof based on DTS. A multi-channel distributed Raman temperature measurement system is used to perform real-time distributed measurement of the temperature of small steel pipes in the boiler furnace roof ladle. The system not only has high measurement sensitivity but also can realize multi-point temperature measurement.

[0004] To achieve the above objectives, the present invention provides a temperature monitoring device for small steel pipes in a boiler furnace top based on DTS, comprising: Multiple flexible temperature sensors are wound around the pipe bank in an S-shaped structure at intervals, so that each flexible temperature sensor spans one steel pipe each time it bends; Fix the first clip, clip it onto the steel pipe, and put it onto the flexible temperature sensor; The second fixing buckle is buckled on the pipe and is put on multiple flexible temperature sensors; The flexible temperature sensor is connected to the demodulator through a communication optical cable.

[0005] Preferably, the flexible temperature sensor is a multimode optical fiber with a polyimide coating.

[0006] From the inside to the outside, a multimode optical fiber consists of a core, a cladding, a polyimide coating, and an optical fiber jacket.

[0007] Preferably, both the first and second fixing buckles comprise a first ferrule, a second ferrule, and a locking assembly. One end of the first ferrule is hingedly connected to one end of the second ferrule, and the other end of the first ferrule is connected to the second ferrule via the locking assembly. A slot is provided on the first or second ferrule on the first fixing buckle; a slot is provided on both the first and second ferrules on the second fixing buckle.

[0008] The locking assembly includes a locking screw and a locking nut. The ends of the first ferrule and the second ferrule are respectively provided with a first "U"-shaped groove and a second "U"-shaped groove. One end of the locking screw is rotatably arranged in the first "U"-shaped groove; the locking screw is engaged with the second "U"-shaped groove by rotation, and the locking nut is threadedly connected to the locking screw.

[0009] The demodulator is a distributed temperature demodulator, preferably a multi-channel distributed optical fiber Raman thermometer.

[0010] A temperature monitoring method for small steel pipes in a boiler furnace top based on DTS includes the following steps: S1: Arrange the multimode optical fiber with polyimide coating in an "S" shape on each group of tubes, and make the same A multimode optical fiber crosses a steel pipe each time it is bent. Four multimode optical fibers are laid on each pipe row to monitor the real-time temperature of each steel pipe. S2: Fix the four multimode optical fibers of each tube row to the steel tube using fixing buckle 1. The four multimode optical fibers are gathered into a tube and fixed in the tube using fixing buckle 2 to guide them out of the furnace. S3: Connect the multimode optical fiber after exiting the furnace to the communication optical cable outside the furnace, and connect the connected communication optical cable to the distributed temperature demodulator to form a distributed optical fiber temperature measurement system; S4: A distributed optical fiber temperature measurement system is used to monitor the temperature of small steel pipes in the boiler roof, and an alarm signal is issued when the temperature is abnormal.

[0011] The distributed temperature interrogator displays and records the temperature change curve of each channel in real time, as well as the temperature curve of any position on the multimode optical fiber that changes with time.

[0012] Compared with the existing technology, it has the following beneficial effects: The present invention uses an "S" shape to lay out multimode optical fibers on the pipe banks. In order to meet the bending radius restrictions of the optical fibers, the same multimode optical fiber crosses a steel pipe each time it bends. Each group of pipe banks uses four multimode optical fibers fixed to the steel pipes via fixed clips. Utilizing the above-mentioned optical fiber laying technology, the distributed optical fiber sensing system can accurately monitor the temperature changes of the small steel pipes in the large package on the boiler roof in real time. This technology not only enables independent monitoring of each boiler steel pipe, but also significantly improves measurement accuracy while reducing overall costs. In addition, the device has strong anti-interference capabilities and excellent stability, making it suitable for long-term stable operation in complex industrial environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only preferred embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0014] Figure 1 This is a schematic diagram of the layout of the temperature monitoring device of the present invention; Figure 2 for Figure 1 A in the middle is an enlarged schematic diagram; Figure 3 Schematic diagram of a multi-channel distributed Raman temperature measurement system of the present invention; Figure 4 This is a schematic diagram of the layout of the temperature monitoring device of the present invention; Figure 5 This is a schematic diagram of a fixing buckle 1 of the present invention; Figure 6 This is a schematic diagram of the second fixing buckle of the present invention; Figure 7 This is the exponential response diagram of the ratio of the intensity of anti-Stokes light to that of Stokes light to temperature.

[0015] Figure markings: 1-multimode optical fiber; 2-fixing buckle 1; 3-fixing buckle 2; 4-demodulator; 5-boiler; 101-first ferrule; 102-second ferrule; 103-locking assembly; 104-slot; 105-first "U"-shaped groove; 106-second "U"-shaped groove; 1031-locking screw; 1032-locking nut. DETAILED DESCRIPTION In order to make it easier to understand the structure of the present invention and the functional features and advantages that can be achieved, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings: Example: like Figures 1 to 6 As shown, the present invention provides a temperature monitoring device for small steel pipes in a boiler furnace top based on DTS, comprising: Multiple flexible temperature sensors are arranged on the pipe bank in an S-shaped structure, so that each flexible temperature sensor crosses a steel pipe with each bend. This arrangement achieves highly stable distributed temperature measurement. Fix the clip 2, clip it onto the steel pipe, and put it on the flexible temperature sensor; The second fixing buckle 3 is buckled on the pipe and put on the multiple flexible temperature sensors; The flexible temperature sensor is connected to the demodulator 4 via a communication optical cable.

[0016] See also Figure 4, the flexible temperature sensor is a multimode optical fiber 1 with a polyimide coating.

[0017] See also Figure 1 The multimode optical fiber 1 includes a core, a cladding, a polyimide coating and an optical fiber sheath layer from the inside to the outside.

[0018] See also Figure 2 、 Figure 5 and Figure 6 The fixing clip 1 2 and the fixing clip 2 3 of the present invention both include a first clip 101, a second clip 102 and a locking assembly 103. One end of the first clip 101 is hinged to one end of the second clip 102, and the other end of the first clip 101 is connected to the second clip 102 through the locking assembly 103; a card groove 104 is provided on the first clip 101 and / or the second clip 102 to fix the multimode optical fiber 1 through the card groove 104, so that the multimode optical fiber 1 can be wound on the tube row in an "S"-shaped structure.

[0019] See also Figure 5 and Figure 6 In the present invention, the card slot 104 is provided on the first card sleeve 101 or the second card sleeve 102 on the fixing card buckle 1 2; the card slot 104 is provided on the first card sleeve 101 and the second card sleeve 102 on the fixing card buckle 2 3. Specifically, there is one card slot 104 on the fixing card buckle 1 2, and four card slots 104 on the fixing card buckle 2 3.

[0020] See also Figure 5 and Figure 6 The locking assembly 103 of the present invention includes a locking screw 1031 and a locking nut 1032. The first and second ends of the first ferrule 101 and 102 are respectively provided with a first "U"-shaped groove 105 and a second "U"-shaped groove 106. One end of the locking screw 1031 is rotatably arranged in the first "U"-shaped groove 105; the locking screw 1031 is engaged with the second "U"-shaped groove 106 by rotation, and the locking nut 1032 is threadedly connected to the locking screw 1031.

[0021] The locking assembly 103 is provided to lock the closed fixing buckle 1 2 and the closed fixing buckle 2 3 so as to fix the multimode optical fiber 1 on the steel pipe and the pipeline.

[0022] See also Figure 3 The demodulator 4 of the present invention is a distributed temperature demodulator, preferably a multi-channel distributed optical fiber Raman thermometer.

[0023] like Figure 1 and Figure 3 As shown, the present invention also proposes a temperature monitoring method for small steel pipes in a boiler furnace top based on DTS, comprising the following steps: S1: A polyimide-coated multimode optical fiber 1 is laid out in an "S" shape on each group of pipes, and each bend of the same multimode optical fiber 1 crosses a steel pipe. Four multimode optical fibers 1 are laid out on each group of pipes to monitor the real-time temperature of each steel pipe. S2: Fix the four multimode optical fibers 1 of each tube row to the steel tube using the fixing buckle 1 2. The four multimode optical fibers 1 are gathered into a tube and fixed in the tube using the fixing buckle 2 3 to guide them out of the furnace. S3: Connect the multimode optical fiber 1 after exiting the furnace to the communication optical cable outside the furnace, and connect the connected communication optical cable to the distributed temperature demodulator to form a distributed optical fiber temperature measurement system; S4: The distributed optical fiber temperature measurement system is used to monitor the temperature of the small steel pipes in the large package on the top of boiler 5, and an alarm signal is issued when the temperature is abnormal.

[0024] The distributed temperature demodulator displays and records the temperature change curve of each channel and the temperature curve of any position on the multimode optical fiber 1 changing with time in real time.

[0025] The temperature measurement principle of the temperature monitoring device for small steel pipes in the boiler furnace top based on DTS of the present invention is as follows: A DTS system typically consists of a pulsed laser, a sensing fiber, a wavelength division multiplexer (WDM), an avalanche diode (AAD), an amplifier, and a signal processing and analysis unit. The temperature measurement principle of this sensing system is as follows: light emitted by a pulsed laser travels along the sensing fiber into the temperature region to be measured. As the laser propagates through the fiber, it continuously generates backscattered Raman light. After filtering by the WDM, only Stokes and anti-Stokes light remain. Anti-Stokes light is highly sensitive to changes in the ambient temperature of the sensing fiber, while Stokes light is independent of temperature fluctuations and serves as a reference light. By monitoring the intensity ratio of anti-Stokes to Stokes light, temperature information about the region to be measured can be obtained. Temperature information can be located based on the light propagation speed in the fiber and the return time of the backscattered light.

[0026] According to Raman scattering theory, the ratio of anti-Stokes light intensity Ias to Stokes light intensity Is is: (1) Where, are the wavelengths of Stokes light and anti-Stokes light, h is Planck's constant, is the Raman frequency shift, K is the Boltzmann constant, and T is the absolute temperature. The temperature T can be decomposed by the relationship described in equation (1): (2) According to the propagation speed of light in the sensing fiber and the return time of the backscattered light, the location of the temperature anomaly can be determined as: (3) Where L is the distance from the short pulse laser incident end to the temperature anomaly point; t is the round trip time of light; and n is the refractive index of the optical fiber. Based on equation (2), the Raman temperature demodulator can obtain the temperature information of the measured area according to the ratio of the anti-Stokes light intensity to the Stokes light intensity, and then according to equation (3), the spatial positioning of the temperature can be achieved.

[0027] See also Figure 7 , which shows the exponential response characteristics of the ratio of the intensity of anti-Stokes light to Stokes light to temperature. Based on this exponential response characteristic, the temperature of the steel pipe can be measured.

[0028] The technical solution of this invention uses multimode optical fiber to accurately monitor the temperature changes of each small steel pipe within the boiler roof ladle in real time. This solution not only meets the needs of multi-point monitoring, but also significantly improves monitoring accuracy while effectively reducing costs. Furthermore, the monitoring device has strong anti-interference capabilities and excellent stability, fully meeting the application requirements of DTS technology in the field of high-precision, multi-point high-temperature monitoring.

[0029] The above are only preferred embodiments of the present invention and are not intended to limit the present invention in any form. Any person skilled in the art can, without departing from the scope of the technical solution of the present invention, use the above technical content to make many possible changes and modifications to the technical solution of the present invention, or modify it into an equivalent embodiment with equivalent changes. Therefore, any changes, modifications, equivalent changes and modifications made to the above embodiments based on the technology of the present invention without departing from the content of the technical solution of the present invention shall fall within the scope of protection of the present technical solution.

Claims

1. The temperature monitoring device of small steel pipes in the boiler furnace top based on DTS is characterized by: include: Multiple flexible temperature sensors are wound around the pipe bank in an "S"-shaped structure at intervals, so that each flexible temperature sensor spans one steel pipe each time it bends; A fixing buckle (2) is buckled on the steel pipe and put on the flexible temperature sensor; A second fixing buckle (3) is buckled on the pipe and is put on the plurality of flexible temperature sensors; The flexible temperature sensor is connected to the demodulator (4) via a communication optical cable.

2. The temperature monitoring device for small steel pipes in a boiler furnace top based on DTS according to claim 1 is characterized in that: The flexible temperature sensor is a multimode optical fiber (1) with a polyimide coating.

3. The temperature monitoring device for small steel pipes in a boiler furnace top based on DTS according to claim 2 is characterized in that: The multimode optical fiber (1) comprises, from the inside to the outside, a fiber core, a cladding, a polyimide coating, and an optical fiber sheath layer.

4. The temperature monitoring device for small steel pipes in a boiler furnace top based on DTS according to claim 3 is characterized in that: The fixing buckle 1 (2) and the fixing buckle 2 (3) both comprise a first clamping sleeve (101), a second clamping sleeve (102) and a locking assembly (103); one end of the first clamping sleeve (101) is hinged to one end of the second clamping sleeve (102), and the other end of the first clamping sleeve (101) is connected to the second clamping sleeve (102) through the locking assembly (103); a clamping slot (104) is provided on the first clamping sleeve (101) and / or the second clamping sleeve (102).

5. The temperature monitoring device for small steel pipes in a boiler furnace top based on DTS according to claim 4 is characterized in that: The card slot (104) is opened on the first card sleeve (101) or the second card sleeve (102) on the fixing buckle 1 (2); the card slot (104) is opened on the first card sleeve (101) and the second card sleeve (102) on the fixing buckle 2 (3).

6. The temperature monitoring device for small steel pipes in a boiler furnace top based on DTS according to claim 5 is characterized in that: The locking assembly (103) includes a locking screw (1031) and a locking nut (1032), and the ends of the first ferrule (101) and the second ferrule (102) are respectively provided with a first "U"-shaped groove (105) and a second "U"-shaped groove (106), and one end of the locking screw (1031) is rotatably arranged in the first "U"-shaped groove (105); the locking screw (1031) is engaged with the second "U"-shaped groove (106) by rotating, and the locking nut (1032) is threadedly connected to the locking screw (1031).

7. The temperature monitoring device for small steel pipes in a boiler furnace top based on DTS according to claim 6 is characterized in that: The demodulator (4) is a distributed temperature demodulator.

8. A temperature monitoring method for small steel pipes in a boiler (5) furnace top based on DTS, characterized in that: The temperature monitoring device for small steel pipes in a boiler furnace top based on DTS according to claim 7 comprises the following steps: S1: The multimode optical fiber (1) with a polyimide coating is arranged in an "S"-shaped structure on each group of pipes, and the same multimode optical fiber (1) is bent once to cross a steel pipe. Four multimode optical fibers (1) are arranged on each group of pipes to monitor the real-time temperature of each steel pipe; S2: The four multimode optical fibers (1) of each tube row are fixed to the steel tube by fixing the first clip (2), and the four multimode optical fibers (1) are gathered into a tube and fixed in the tube by fixing the second clip (3) to guide them out of the furnace; S3: Connect the multimode optical fiber (1) after it comes out of the furnace to the communication optical cable outside the furnace, and connect the connected communication optical cable to the distributed temperature demodulator to form a distributed optical fiber temperature measurement system; S4: A distributed optical fiber temperature measurement system is used to monitor the temperature of the small steel pipes in the large package on the top of the boiler (5) and to send out an alarm signal when the temperature is abnormal.

9. The temperature monitoring method of small steel pipes in the furnace top of a boiler (5) based on DTS according to claim 8 is characterized in that: The distributed temperature demodulator displays and records the temperature change curve of each channel in real time, as well as the temperature curve of any position on the multimode optical fiber (1) that changes with time.

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