A method for detecting pipeline blockage and its application

Abstract

The present invention discloses a detection method and application for pipeline blockage. The method includes the following steps: several fiber Bragg grating temperature sensors are closely attached to the pipeline wall and are electrically connected to a detection controller; several temperature measurement points are set on the fiber Bragg grating temperature sensors; the temperature of the substance in the pipeline is adjusted, and the temperature of the pipeline wall at the temperature measurement points is monitored in real time and transmitted to the detection controller through the fiber Bragg grating temperature sensors, and the heating feedback curves of each temperature measurement point are drawn to determine the location of the blockage point. In the present invention, a single fiber Bragg grating temperature sensor can be used to achieve temperature detection at all temperature measurement points, with small measurement errors, high accuracy, and low cost. The heating feedback curves are drawn based on the temperature data, which is more intuitive. The blockage situation is judged according to the temperature feedback of each temperature measurement point, and the blockage point can be found in the initial stage, greatly improving the operation safety and stability. The detection process does not require shutdown and is applicable to the blockage judgment of urea pyrolysis pipelines or other similar pipelines.

Description

Technical Field

[0001] The present invention belongs to the technical field of air pollution control, and particularly relates to a detection method for pipeline blockage and its application. Background Art

[0002] Selective catalytic reduction is the mainstream technology for flue gas denitrification. At present, there are three most widely used reducing agents in denitrification devices in the world: liquid ammonia, ammonia water, and urea. Considering from the safety perspective, urea is the safest during transportation, storage, and use, and is the most widely used.

[0003] The temperature of the urea pyrolysis furnace is required to reach above 360°C, and the temperature of the ammonia mixture transmission pipeline after pyrolysis is also required to reach above 110°C. If the temperature cannot reach, it is very easy to have incomplete decomposition problems in the pyrolysis furnace or transmission pipeline, generating intermediate polymers such as melamine and gradually blocking the lower part of the pyrolysis furnace or the transmission pipeline. Melamine is insoluble in water and is very difficult to treat online. If blockage occurs, only shutdown can be carried out to check section by section until the blockage point is found, and then maintenance can be carried out. This method not only has high maintenance costs, but also has a very large impact on production. Summary of the Invention

[0004] In order to solve the technical problems existing in the prior art, the purpose of the present invention is to provide a detection method for pipeline blockage and its application.

[0005] In order to achieve the above purpose and reach the above technical effects, the technical solution adopted by the present invention is as follows:

[0006] A detection method for pipeline blockage includes the following steps:

[0007] 1) Installation of temperature measurement sensors

[0008] Attach several fiber Bragg grating temperature sensors to the pipeline wall, and electrically connect the fiber Bragg grating temperature sensors to the detection controller;

[0009] 2) Setting of temperature measurement points

[0010] Set several temperature measurement points on the fiber Bragg grating temperature sensors, and detect the pipeline wall temperature at at least one or all of the temperature measurement points;

[0011] 3) Variable temperature detection

[0012] Adjust the temperature of the substance in the pipeline, and through the fiber Bragg grating temperature sensors, real-time online monitor the pipeline wall temperature at the temperature measurement points and transmit it to the detection controller for analysis and processing, draw the heating feedback curves of each temperature measurement point, and determine the location of the blockage point;

[0013] There is no sequence requirement between step 1) and step 2).

[0014] In step 1), there is one fiber grating temperature sensor in total, which is closely attached to the outer wall of the pipeline. The fiber grating temperature sensor is wrapped with a heat-insulating layer outside. The temperature measurement sensitivity of the fiber grating temperature sensor is 0.1 °C, and the test temperature range is 0 - 400 °C.

[0015] In step 2), the pipeline wall temperature at all temperature measurement points is detected by one fiber grating temperature sensor.

[0016] In step 3), the steps of variable temperature detection include:

[0017] Firstly, the pipeline wall temperature at each temperature measurement point in the initial state is detected by the fiber grating temperature sensor.

[0018] After running for a period of time, the temperature of the substance in the pipeline is increased to T1. The pipeline wall temperature at each temperature measurement point is detected by the fiber grating temperature sensor and transmitted to the detector for analysis and processing. The heating feedback curve of each temperature measurement point is drawn. If the pipeline wall temperature at each temperature measurement point increases uniformly, it indicates that there is no condensation or accumulation of substances at each temperature measurement point. Otherwise, the location of the blockage point is judged.

[0019] After running for a period of time continuously, condensation or accumulation of substances appears at a certain place on the pipeline wall. The temperature of the substance in the pipeline is increased to T2. The pipeline wall temperature at each temperature measurement point is detected by the fiber grating temperature sensor and transmitted to the detector for analysis and processing. The heating feedback curve of each temperature measurement point is drawn. The temperature measurement point with abnormal heating rate is found and used as the blockage point.

[0020] The present invention also discloses the application of a pipeline blockage detection method in the blockage judgment of urea pyrolysis pipelines or other similar pipelines.

[0021] Compared with the prior art, the beneficial effects of the present invention are:

[0022] The present invention discloses a detection method and application for pipeline blockage. The detection method includes the following steps: closely attach a plurality of fiber Bragg grating temperature sensors to the pipeline wall, and electrically connect the fiber Bragg grating temperature sensors to a detection controller; set a plurality of temperature measurement points on the fiber Bragg grating temperature sensors, and detect the pipeline wall temperature at at least one or all of the temperature measurement points; adjust the temperature of the substance in the pipeline, and in real-time online monitor the pipeline wall temperature at the temperature measurement points through the fiber Bragg grating temperature sensors and transmit it to the detection controller for analysis and processing, draw the heating feedback curve of each temperature measurement point, and determine the location of the blockage point. In the present invention, a single fiber Bragg grating temperature sensor can be used to achieve the temperature detection at all temperature measurement points, with small measurement error, higher accuracy, low cost, draw the heating feedback curve according to the temperature data, which is more intuitive, and because the heating feedback is dynamic, when crystallization occurs in the pipeline, due to the poor thermal conductivity of the crystalline substance, the temperature here will show a decreasing trend. By using the variable temperature detection method and judging the blockage situation according to the temperature feedback of each temperature measurement point, the blockage point can be found in the initial stage, greatly improving the operation safety and stability, the result is more real and reliable, and the production loss is basically not caused during the detection process as it does not require shutdown, which is applicable to the blockage judgment of urea pyrolysis pipelines or other similar pipelines and is suitable for industrial mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the result of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0024] The present invention will be described in detail below so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making the protection scope of the present invention more clearly defined.

[0025] The following gives a brief overview of one or more aspects to provide a basic understanding of these aspects. This overview is not an exhaustive survey of all contemplated aspects, and is neither intended to identify key or decisive elements of any or all aspects nor to attempt to define the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that follows.

[0026] As Figure 1 shown, a detection method for pipeline blockage includes the following steps:

[0027] 1) Installation of temperature sensors

[0028] Set the position of the detection controller 1, closely attach a plurality of fiber Bragg grating temperature sensors 2 to the outer wall of the pipeline, and electrically connect the fiber Bragg grating temperature sensors 2 to the detection controller 1;

[0029] Preferably, only one fiber Bragg grating temperature sensor 2 is provided, and its exterior is coated with a heat-insulating layer 3;

[0030] 2) Setting of temperature measurement points

[0031] Several temperature measurement points are set on the fiber optic grating temperature sensor 2 to detect the temperature of the pipeline wall at at least one or all of the temperature measurement points; preferably, the temperature of the pipeline wall at all temperature measurement points is detected by one fiber optic grating temperature sensor 2;

[0032] 3) Variable temperature detection

[0033] Adjust the temperature of the substance in the pipeline, and through the fiber optic grating temperature sensor 2, the temperature of the pipeline wall at the corresponding temperature measurement points is monitored in real time and transmitted to the detection controller 1 for analysis and processing, draw the heating feedback curves of each temperature measurement point, and determine the location of the blockage point;

[0034] There is no order of precedence between step 1) and step 2).

[0035] In step 3), the steps of variable temperature detection specifically include:

[0036] First, the temperature of the pipeline wall at each temperature measurement point in the initial state is detected by the fiber optic grating temperature sensor 2;

[0037] After running for a period of time, raise the temperature of the substance in the pipeline to T1, detect the temperature of the pipeline wall at each temperature measurement point by the fiber optic grating temperature sensor 2 and transmit it to the detection controller 1 for analysis and processing, draw the heating feedback curves of each temperature measurement point. If the temperature of the pipeline wall at each temperature measurement point rises uniformly, it means that there is no substance condensation or accumulation at each temperature measurement point. Otherwise, determine the location of the blockage point;

[0038] After running for a period of time, substance condensation or accumulation appears at a certain place on the pipeline wall; raise the temperature of the substance in the pipeline to T2, detect the temperature of the pipeline wall at each temperature measurement point by the fiber optic grating temperature sensor 2 and transmit it to the detection controller 1 for analysis and processing, draw the heating feedback curves of each temperature measurement point, and find the temperature measurement point with abnormal heating rate as the blockage point.

[0039] The temperature measurement sensitivity of the fiber optic grating temperature sensor 2 can reach 0.1 °C, the temperature range can reach 0 - 400 °C, and the single - root laying length can reach 50 m.

[0040] The present invention also discloses the application of a pipeline blockage detection method in the judgment of blockage in urea pyrolysis pipelines or other similar pipelines.

[0041] Embodiment 1

[0042] As Figure 1 shown, a pipeline blockage detection method includes the following steps:

[0043] A fiber Bragg grating temperature sensor 2 is closely attached to the outer wall of the urea pyrolysis pipeline. The detection controller 1 is electrically connected to the fiber Bragg grating temperature sensor 2. The temperature measurement sensitivity of the fiber Bragg grating temperature sensor 2 can reach 0.1 °C, the temperature range can reach 0 - 400 °C, and the single-laying length can reach 50 m. The fiber Bragg grating temperature sensor 2 is coated with a thermal insulation layer 3 on the outside;

[0044] Several temperature measurement points are set on the fiber Bragg grating temperature sensor 2. Temperature measurement points A, B... are sequentially arranged along the flue gas flow direction. The pipeline wall temperature at each temperature measurement point is monitored in real time and online through the fiber Bragg grating temperature sensor 2 and transmitted to the detector for analysis and processing, and then the location of the blockage point is judged.

[0045] Initially, there is no blockage in the urea pyrolysis pipeline, the surface is smooth, the operating temperature inside the pipeline is 150 °C, the pipeline wall temperature is initially uniform, and the temperatures measured at each temperature measurement point are basically the same after stabilization, maintaining at 150 ± 2 °C;

[0046] In the first month of operation, a variable temperature detection is carried out: the temperature of the substance inside the pipeline is increased to 170 °C. Since there is no condensation or accumulation everywhere, the pipeline wall temperature at the temperature measurement points rises uniformly;

[0047] After continuing to operate for two months, due to flow rate or other reasons, substances such as melamine condense at temperature measurement point A and adsorb on the inner wall of the pipeline; a variable temperature detection is carried out to increase the temperature of the fluid inside the pipe. Since the thermal conductivity of deposits such as melamine is poor, the heating rate at temperature measurement point A is significantly lower than the heating rates at other temperature measurement points, so it is judged that there is melamine accumulation at temperature measurement point A, and the blockage point is at temperature measurement point A.

[0048] For the parts or structures not specifically described in the present invention, existing technologies or existing products can be adopted, and no further elaboration will be made here.

[0049] The above are only the embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. All equivalent structural or equivalent process transformations made by using the content of the specification of the present invention, or directly or indirectly applied to other related technical fields, are equally included in the patent protection scope of the present invention.

Claims

1. A method for detecting pipeline blockage, characterized in that, It includes the following steps: 1) Installation of the temperature measurement sensor Attach several fiber grating temperature measurement sensors to the pipeline wall, and electrically connect the fiber grating temperature measurement sensors to the detection controller; 2) Setting of the temperature measurement points Set several temperature measurement points on the fiber grating temperature measurement sensors, and detect the temperature of the pipeline wall at at least one or all of the temperature measurement points; 3) Variable temperature detection Adjust the temperature of the substance in the pipeline, and use the fiber grating temperature measurement sensors to monitor the temperature of the pipeline wall at the temperature measurement points in real time and online, and transmit it to the detection controller for analysis and processing, draw the heating feedback curves of each temperature measurement point, and determine the location of the blockage point; In step 3), the steps of variable temperature detection include: First, use the fiber grating temperature measurement sensors to detect the temperature of the pipeline wall at each temperature measurement point in the initial state; After running for a period of time, raise the temperature of the substance in the pipeline to T1, use the fiber grating temperature measurement sensors to detect the temperature of the pipeline wall at each temperature measurement point and transmit it to the detector for analysis and processing, draw the heating feedback curves of each temperature measurement point. If the temperature of the pipeline wall at each temperature measurement point rises uniformly, it means that there is no substance condensation or accumulation at each temperature measurement point. Otherwise, determine the location of the blockage point; After running for another period of time, substance condensation or accumulation occurs at a certain place on the pipeline wall; raise the temperature of the substance in the pipeline to T2, use the fiber grating temperature measurement sensors to detect the temperature of the pipeline wall at each temperature measurement point and transmit it to the detector for analysis and processing, draw the heating feedback curves of each temperature measurement point, and find the temperature measurement point with abnormal heating speed as the blockage point; There is no sequence requirement between step 1) and step 2).

2. The detection method for pipeline blockage according to claim 1, wherein, In step 1), only one fiber grating temperature measurement sensor is provided.

3. The detection method for pipeline blockage according to claim 2, wherein, The outside of the fiber grating temperature measurement sensor is coated with a heat-insulating layer.

4. The detection method for pipeline blockage according to claim 2, characterized in that The temperature measurement sensitivity of the fiber grating temperature measurement sensor is 0.1°C, and the test temperature range is 0 - 400°C.

5. The detection method for pipeline blockage according to claim 2, wherein, In step 2), the temperature of the pipeline wall at all temperature measurement points is detected by one fiber grating temperature measurement sensor.

6. Application of a pipeline blockage detection method according to any one of claims 1 - 5 in the judgment of blockage in urea pyrolysis pipelines or other similar pipelines.

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