A steam pipeline condensation monitoring method based on non-equilibrium condensation temperature recovery characteristics

Abstract

The present application belongs to the technical field of steam pipeline monitoring, and discloses a steam pipeline condensation monitoring method based on non-equilibrium condensation temperature recovery characteristics. After non-equilibrium condensation occurs, steam almost absorbs all the latent heat of condensation, and the temperature of steam usually rises during condensation, which is called "temperature recovery". This non-equilibrium condensation "temperature recovery" feature is found in existing steam pipeline test measurements. When steam flows in the pipeline, if condensation does not occur, the temperature of steam will decrease due to heat loss; if "temperature recovery" occurs, it indicates that condensation occurs in the flowing steam. Therefore, by measuring the temperature change of the pipe section, it can be determined whether condensation occurs in the steam. By using the "temperature recovery" characteristics of non-equilibrium condensation of steam pipeline, the temperature change of the pipe section is measured to determine whether condensation occurs in the steam pipeline, which has the advantages of less measurement parameters, simple process, low cost and large-scale market application prospect.

Description

Technical Field

[0001] This invention relates to the field of steam pipeline monitoring, and in particular to a steam pipeline condensation monitoring method based on non-equilibrium condensation recovery characteristics. Background Technology

[0002] Steam pipelines are prone to saturated condensation due to long distances and variable loads, resulting in condensation losses in the heating network, which requires close attention.

[0003] Currently, there are few applicable methods for monitoring condensation in steam pipelines, and no condensation monitoring technology has been widely adopted in the market. Existing monitoring technologies mainly include steam quality measurement (superheat, dryness, and non-condensable gas content, etc.) and condensate measurement. These methods involve many measurement parameters, are costly, and cannot be widely promoted and applied.

[0004] If steam begins to condense only when it is in a supersaturated state, it is called non-equilibrium condensation. Non-equilibrium condensation of steam is a common phenomenon in the fields of power, chemical industry, nuclear energy and metallurgy. There are sufficient research results on non-equilibrium condensation of high-speed flowing steam such as steam turbines and nozzles, but there are few reports on non-equilibrium condensation of steam pipelines.

[0005] This invention patent is the first to utilize the "temperature recovery" phenomenon during unbalanced condensation in steam pipes. It determines whether condensation has occurred in the steam pipe by measuring the temperature change of the pipe section. The measurement process is simple, low-cost, and has the potential for large-scale market application. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a steam pipeline condensation monitoring method based on the non-equilibrium condensation and temperature recovery characteristics, which can monitor the condensation status of steam pipelines in real time.

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0008] This invention provides a steam pipeline condensation monitoring method based on non-equilibrium condensation and temperature recovery characteristics. On the monitored pipe section, including the steam pipe and the insulation layer, n measuring points (n≥2) are arranged. The measuring points adopt two methods: insulation surface temperature (method 1) and steam temperature measurement (method 2).

[0009] Because the condensation of steam in the pipeline is non-equilibrium condensation, after non-equilibrium condensation occurs, the steam absorbs almost all of its latent heat of condensation. As condensation proceeds, the steam temperature rises, resulting in a temperature rebound. If steam flows in the pipeline and no condensation occurs, the steam temperature will drop due to heat loss. If a "temperature rebound" occurs, it indicates that condensation has occurred in the steam flow. Therefore, when an increase in temperature is detected at adjacent measuring points along the flow direction among n points in the flow distribution, it indicates that non-equilibrium condensation and temperature rebound have occurred. This indicates that steam condensation has occurred, and an alarm signal is issued.

[0010] As a preferred embodiment of the present invention, the measuring point employs two methods: measuring the surface temperature of the insulation layer (Method 1) and measuring the steam temperature (Method 2).

[0011] Method 1 is to use the insulation surface temperature measurement method to measure the temperature at the outside of the insulation layer. It is not limited to single-point measurement. Multiple points can be evenly distributed along the circumference to take the average value. For example, take 4 points on the top, bottom, left and right of the circumference to measure the temperature and take the average value.

[0012] Method 2 is to use steam temperature measurement with temperature measuring points inside the pipe, not limited to single-point measurement, for example, taking the average of two points on the top and bottom of a circular pipe.

[0013] Existing studies on high-speed flow in steam nozzles have shown that, unlike equilibrium condensation flow, non-equilibrium condensation flow does not condense in the region between the saturation line and the Wilson line; instead, it continues to expand according to the properties of superheated steam. After non-equilibrium condensation occurs, the steam absorbs almost all of its latent heat of condensation, and the steam temperature usually rises as condensation progresses, exhibiting a "warming-up" phenomenon. This non-equilibrium condensation "warming-up" phenomenon has also been confirmed in existing steam pipeline test measurements. When steam flows in a pipeline, if condensation does not occur, the steam temperature will decrease due to heat loss; if "warming-up" occurs, it indicates that condensation has occurred during the steam flow. Therefore, by measuring the temperature change of a pipe section, it is possible to determine whether steam condensation has occurred.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0015] This invention is the first to discover and utilize the "rebound" characteristic of unbalanced condensation in steam pipelines. The monitoring system only monitors the temperature change of the steam pipeline section to determine whether condensation has occurred. The technical principle of this invention is clear, the system is simple and reliable, the cost is low, and it has promotional value. It helps guide the safe and economical operation of steam pipeline networks and the upgrading and transformation of pipeline networks, reduces pipeline losses, and achieves safe and economical gas supply. Attached Figure Description

[0016] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0017] Figure 1 This is a schematic diagram of the overall cross-sectional structure of the present invention;

[0018] In the diagram: 1. Steam pipe; 2. Insulation layer; 3. Temperature measuring point outside the insulation layer; 4. Temperature measuring point inside the pipe. Detailed Implementation

[0019] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0020] In the attached diagram, all identical reference numerals refer to the same components.

[0021] Example 1

[0022] Please see Figure 1 This invention provides a steam pipeline condensation monitoring method based on the non-equilibrium condensation "return temperature" characteristic. The monitored pipe section includes a steam pipe 1 and an insulation layer 2, with n measuring points (n≥2). The measuring points adopt two methods: insulation surface temperature measurement (method 1) and steam temperature measurement (method 2).

[0023] Method 1: Use the insulation surface temperature measurement method. Use 3 temperature measurement points on the outside of the insulation layer. It is not limited to single-point measurement. Multiple points can be evenly distributed along the circumference and the average value is taken. For example, take 4 points on the top, bottom, left and right of the circumference and take the average value.

[0024] Method 2: Use steam temperature measurement with 4 temperature measurement points inside the pipe. It is not limited to single-point measurement. For example, take 2 points on the top and bottom of the round pipe and take the average value.

[0025] Regardless of whether method one or method two is adopted, if the temperature rises at adjacent measuring points along the flow direction within n points of the flow distribution, it indicates that non-equilibrium condensation "warming up" has occurred, indicating that steam condensation has occurred, and an alarm signal is issued.

[0026] The distance between two adjacent measuring points is 100-5000m, based on existing engineering practice experience.

[0027] The inventors discovered that flow condensation in steam pipelines is non-equilibrium condensation. When non-equilibrium condensation occurs, the steam absorbs almost all of its latent heat of condensation. As condensation progresses, the steam temperature typically rises, exhibiting a "warming-up" phenomenon. If steam flows through a pipeline without condensation, its temperature will decrease due to heat loss; however, if a "warming-up" occurs, it indicates that condensation has taken place during the steam's flow. Therefore, measuring the temperature change in a pipe section can determine whether steam condensation has occurred.

[0028] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for monitoring condensation in steam pipelines based on non-equilibrium condensation and temperature recovery characteristics, characterized in that, On the monitored pipe section, including steam pipe (1) and insulation layer (2), n measuring points (n≥2) are arranged. The measuring points adopt two methods: insulation surface temperature (method 1) and steam temperature measurement (method 2). Because the condensation during steam flow in the pipeline is non-equilibrium condensation, the steam temperature rises after non-equilibrium condensation occurs, resulting in a temperature rebound. If steam does not condense during its flow in the pipeline, the steam temperature will drop due to heat loss. If a "temperature rebound" occurs, it indicates that condensation has occurred during the steam flow. Therefore, when an increase in temperature is detected at adjacent measuring points along the flow direction among n points in the flow distribution, it indicates that non-equilibrium condensation and temperature rebound have occurred, and an alarm signal is issued to determine that steam condensation has occurred. This steam pipeline is a long-distance pipeline.

2. The steam pipeline condensation monitoring method based on non-equilibrium condensation recovery characteristics according to claim 1, characterized in that, The measuring points employ two methods: measuring the surface temperature of the insulation layer (Method 1) and measuring the steam temperature (Method 2). Method 1 is: using the insulation surface temperature measurement method, take the temperature measurement point (3) on the outside of the insulation layer, take 4 points on the circumference, and take the average value; Method 2 is to use steam temperature measurement with the temperature measuring point (4) inside the pipe, and take the average value after taking 2 points at the top and bottom of the round pipe.

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