Water leakage on-line monitoring system for low-temperature economizer in flue gas deep waste heat recovery system

Abstract

The invention provides a low-temperature economizer water leakage on-line monitoring system in a flue gas deep waste heat recovery system, and relates to the technical field of flue gas low-temperature economizer water leakage detection, the system comprises a data management layer and a leakage monitoring layer, the data management layer comprises a main controller module and a central control module, the leakage monitoring layer comprises a plurality of groups of multi-channel control modules and liquid leakage sensing modules, the number of the liquid leakage sensing modules corresponds to the number of channels of the multi-channel control modules, and the plurality of groups of multi-channel control modules are connected with the main controller module; according to the invention, the liquid leakage sensing module in the form of the sensing belt is adopted, and the multi-channel control module is used for carrying out data integration on the liquid leakage sensing module, so that the device has the advantage of convenience in arrangement, is easy to install at key parts of equipment or a pipeline, does not occupy extra space, and further judges whether liquid leakage exists or not according to the change of current magnitude; and the sensitivity is good.

Description

Technical Field

[0001] The present invention relates to the technical field of water leakage detection for flue gas low-temperature economizers, and in particular to an online monitoring system for water leakage for low-temperature economizers in a flue gas deep waste heat recovery system. Background Art

[0002] The flue gas low-temperature economizer is a heat exchange device that uses the waste heat of the flue gas at the tail of the boiler to heat condensate or heat medium water. Its main purpose is to recover the low-grade heat energy in the boiler flue gas, thereby improving energy efficiency and reducing fuel consumption and operating costs. However, due to its complex working environment, it faces multiple challenges, including high dust concentration in the flue gas and strong corrosiveness of the medium, which can easily lead to equipment failure.

[0003] One of the typical problems is water leakage in low-temperature economizers. Water leakage not only directly affects the heat exchange efficiency, but also may cause a series of production safety hazards. If the water leakage is not discovered in time and countermeasures are not taken quickly, it may lead to serious production accidents. For example, after water enters the flue, it combines with dust and ash in the flue gas to form a muddy substance, which adheres to the inner wall of the flue and gradually blocks the flue, resulting in poor exhaust of the boiler and affecting the normal operation of the boiler.

[0004] Therefore, in order to prevent the occurrence of the above-mentioned situation, it is necessary to detect water leakage during the operation process. However, the existing detection system technology has certain limitations. For example, the traditional pressure monitoring system or the flow abnormality alarm system has a low detection sensitivity for tiny water leakage, and it is often difficult to detect problems in the early stage. At the same time, the distribution of the detection system is not easy to set up, which leads to certain difficulties in the actual deployment of the system. Therefore, the present invention proposes an online monitoring system for water leakage of a low-temperature economizer in a flue gas deep waste heat recovery system to solve the problems existing in the prior art. Summary of the invention

[0005] In view of the above problems, the purpose of the present invention is to propose an online monitoring system for water leakage of a low-temperature economizer in a flue gas deep waste heat recovery system. This online monitoring system for water leakage of a low-temperature economizer in a flue gas deep waste heat recovery system has the advantages of high sensitivity and easy deployment, and solves the problems existing in the prior art.

[0006] To achieve the purpose of the present invention, the present invention is implemented through the following technical solutions: an online monitoring system for water leakage of a low-temperature economizer in a flue gas deep waste heat recovery system, comprising a data management layer and a leakage monitoring layer, the data management layer and the leakage monitoring layer are connected wirelessly or wired, the data management layer comprises a main controller module for management and summary and a central control module for personnel operation, and the output end of the main controller module is connected to the input end of the central control module, the leakage monitoring layer comprises a multi-channel control module for controlling leakage detection and a leakage sensing module for detecting leakage, the leakage sensing modules are provided with several groups, and the number of leakage sensing modules corresponds to the number of channels of the multi-channel control modules, the multi-channel control modules are provided with several groups, and several groups of the multi-channel control modules are connected to the main controller module, the leakage sensing module comprises a leakage sensing unit, a starting connection unit and a terminal connection unit, the two ends of the leakage sensing unit are respectively connected to the starting connection unit and the terminal connection unit, and the starting connection unit is connected to the multi-channel control module.

[0007] A further improvement is that the liquid leakage sensing unit comprises a liquid leakage sensor and a liquid leakage sensing plate, and the liquid leakage sensor is mounted on the liquid leakage sensing plate.

[0008] A further improvement is that the liquid leakage sensor is in the form of a sensing belt, the material of the sensing belt is polytetrafluoroethylene, and the leakage judgment basis of the liquid leakage sensor is the current size.

[0009] A further improvement is that the multi-channel control module has two detection modes: liquid leakage and sensor membrane damage.

[0010] A further improvement is that: the leakage monitoring layer also includes an acoustic and visual alarm module, and the input end of the acoustic and visual alarm module is connected to the output end of the liquid leakage sensing module.

[0011] A further improvement is that the prompt levels of the sound and light alarm module are divided into three levels: normal, leakage and rupture, and each level provides different lights and sounds.

[0012] A further improvement is that the central control module includes an operating platform unit, a data storage unit and a graphic display unit.

[0013] A further improvement is that the surface roughness of the liquid leakage sensor Ra is less than 0.2.

[0014] A further improvement is that: the sensing belt is provided with detection holes, and the detection holes are provided in a plurality of groups, and the detection holes in the plurality of groups are spaced 10 mm apart.

[0015] A further improvement is that: a leakage determination threshold value A is preset in the multi-channel control module, the leakage determination threshold values ​​A corresponding to each group of leakage sensing modules are inconsistent, and the leakage determination threshold value A ≥ 1KΩ.

[0016] The beneficial effects of the present invention are as follows: the present invention adopts a leakage sensing module in the form of a sensing belt, and then integrates the data of the leakage sensing module through a multi-channel control module. It has the advantage of convenient layout and is easy to be installed in key parts of equipment or pipelines without taking up extra space. It further uses the change in current size to determine whether there is a leakage. It has good sensitivity and is not only easy to integrate into existing systems without the need for complex algorithms and hardware, but also can realize continuous monitoring and dynamic alarm through real-time collection of current signals, facilitating remote management of personnel. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the system structure of the present invention.

[0018] Figure 2 It is a schematic diagram of performance specifications of the liquid leakage sensing belt of the present invention. DETAILED DESCRIPTION

[0019] In order to deepen the understanding of the present invention, the present invention will be further described in detail below in conjunction with examples. The examples are only used to explain the present invention and do not constitute a limitation on the protection scope of the present invention.

[0020] The flue gas low-temperature economizer is a heat exchange device that uses the waste heat of the flue gas at the tail end of the boiler to heat condensate or heat medium water. Its main purpose is to recover the low-grade thermal energy in the boiler flue gas, thereby improving energy utilization efficiency, reducing fuel consumption and operating costs. However, due to the influence of the working environment, water leakage may occur, so it is necessary to monitor the leakage.

[0021] Flue gas low-temperature economizers usually operate in high-dust and high-humidity environments, which can easily interfere with the normal operation of sensors and cause false alarms or missed alarms. Existing water leakage detection devices are still insufficient in reliability and stability when facing complex working conditions, such as small equipment footprint, etc. The present application has the advantage of convenient deployment, small footprint, and can be deployed wherever required. Each liquid leakage sensing module corresponds to an independent number and address information. Therefore, when a water leakage occurs, each liquid leakage sensing module will not affect each other. At the same time, because it has independent information, it is convenient for personnel to directly see the location information of the water leakage from the system.

[0022] Then according to Figure 1-Figure 2As shown, this embodiment proposes an online monitoring system for water leakage of a low-temperature economizer in a flue gas deep waste heat recovery system, including a data management layer and a leakage monitoring layer. The data management layer and the leakage monitoring layer are connected wirelessly or wired, wherein the wired connection method adopts RS485 communication protocol for data transmission, and the wireless method adopts Wi-Fi communication technology for data transmission. The corresponding settings are made according to the actual deployment scenario. In this embodiment, the data management layer is mainly suitable for data management with this system and operations of back-end management personnel, while the leakage monitoring layer is used for deployment in actual equipment.

[0023] The data management layer includes a main controller module for management and summary and a central control module for personnel operation, and the output end of the main controller module is connected to the input end of the central control module. The main controller module is responsible for connecting with the multi-channel control module in the leakage monitoring layer. It is responsible for supervising the multi-channel control module and transmitting its data to the central control module, that is, by collecting the real-time monitoring data fed back by it, it is managed and processed uniformly, and then it is responsible for transmitting the sorted and processed monitoring data to the central control module for personnel to view, analyze and make decisions. Correspondingly, when personnel operate, corresponding instructions can be issued through the central control module, which will be received and executed by the main controller module, coordinating the multi-channel control module to complete related tasks.

[0024] For the central control module, it is used to display real-time monitoring data and status information, so that operators can check water leakage and system operation status. Accordingly, the central control module includes an operation platform unit, a data storage unit and a graphic display unit. The operation platform unit serves as the core interface of human-computer interaction, allowing operators to input operation instructions through keyboards, touch screens or buttons, while the data storage unit is responsible for storing historical operation data, alarm records, operation logs, etc., to support long-term data storage needs. The graphic display unit displays real-time data, historical curves and operation status in a graphical way to help operators intuitively understand the system working status. Graphical methods include trend charts, bar charts and status tables.

[0025] The leakage monitoring layer includes a multi-channel control module for controlling leakage detection and a leakage sensing module for detecting leakage. The leakage sensing module is provided with several groups, and the number of the leakage sensing modules corresponds to the number of channels of the multi-channel control module. The multi-channel control module is provided with several groups, and several groups of multi-channel control modules are connected to the main controller module. In this embodiment, the multi-channel control module takes a four-channel controller as an example, which can be connected to four groups of leakage sensing modules and ensure that each leakage sensing module is used independently. Specifically, the four-channel controller model is DGS-MO4C leakage controller, and its detection mode is liquid leakage and sensor membrane damage.

[0026] Furthermore, the leakage controller can be set to shorten or extend the time for confirming leakage, so that in certain special circumstances, such as short-term behaviors such as stepping on the sensor and cleaning the floor, the leakage alarm will not be activated. That is, the judgment time for confirming leakage can be set at 2s to 15s. Correspondingly, the longer the leakage time, the lower the false alarm rate.

[0027] The liquid leakage sensing module includes a liquid leakage sensing unit, a starting connection unit and a terminal connection unit. The two ends of the liquid leakage sensing unit are connected to the starting connection unit and the terminal connection unit respectively. The starting connection unit is connected to the multi-channel control module. The liquid leakage sensing unit determines whether there is liquid leakage by detecting the current change caused by the leakage, and the starting connection unit is responsible for connecting the liquid leakage sensing unit to the multi-channel control module. The terminal connection unit forms a complete signal loop with the starting connection unit, and transmits the detection result of the sensing unit to the multi-channel control module in a closed manner to ensure signal integrity. In this embodiment, a 18MΩ resistor is provided in the terminal connection unit.

[0028] The liquid leakage sensing unit includes a liquid leakage sensor and a liquid leakage sensing board. The liquid leakage sensor is mounted on the liquid leakage sensing board. In this embodiment, the liquid leakage sensor is in the form of a sensing strip with a width of 28 mm, i.e., a liquid leakage sensing strip. The liquid leakage sensing strip is mounted on the liquid leakage sensing board by fixing it with a pressure strip. The sensing strip is made of polytetrafluoroethylene and is resistant to high temperatures of 180°C. The leakage judgment basis of the liquid leakage sensor is the current size. In this embodiment, the liquid leakage sensing strip is a DGS-TD01 liquid leakage sensing strip, such as Figure 2 The following are the performance specifications of the leak sensor tape.

[0029] Furthermore, the leakage sensing belt is provided with detection holes, and the detection holes are provided with several groups. The several groups of detection holes are symmetrically arranged on both sides of the leakage sensing belt. The detection holes of the leakage sensing belt are 10 mm apart, and a certain hole distance (spacing) is maintained, which effectively reduces the false alarm rate under high humidity environment and other impurities. At the same time, the surface roughness of the leakage sensor Ra is less than 0.2, which is a smooth plane without grooves and gaps, reducing the possibility of dust or impurity accumulation and greatly reducing false alarms.

[0030] The leakage monitoring layer also includes an audio-visual alarm module, the input end of the audio-visual alarm module is connected to the output end of the leakage sensing module, and the prompt level of the audio-visual alarm module is divided into three levels: normal, leakage and rupture (referring to the situation where the leakage sensing belt is damaged). The lights and sounds provided by each level are different. Correspondingly, a leakage judgment threshold A is preset in the multi-channel control module. The leakage judgment threshold A corresponding to each group of leakage sensing modules is inconsistent. The leakage judgment threshold A ≥ 1KΩ, for example, the leakage judgment threshold A is 5KΩ, 10KΩ, 100KΩ, etc., and the threshold can be set arbitrarily. The closer the threshold is to the initial value (the resistance value of the leakage sensing belt itself), the higher the sensitivity, but the false alarm rate is relatively high. Therefore, in actual use, appropriate adjustments are made according to needs to reduce the false alarm rate. When working, when the sensor is in a normal state, there is no conductive liquid involved in the circuit, and the resistance is high, so the current remains at a normal value. Once leakage occurs, the conductive liquid contacts the sensing area of ​​the sensor, and the conductivity of the liquid forms a new current path between the two poles, causing the total resistance to decrease, thereby increasing the current passing through. The value of the total resistance decrease is then compared with the leakage judgment threshold A, and the judgment is made based on the comparison result.

[0031] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited by the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the framework and scope of application of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. An online monitoring system for water leakage of a low-temperature economizer in a flue gas deep waste heat recovery system, characterized in that: It includes a data management layer and a leakage monitoring layer, which are connected wirelessly or wiredly. The data management layer includes a main controller module for management and summary and a central control module for personnel operation, and the output end of the main controller module is connected to the input end of the central control module. The leakage monitoring layer includes a multi-channel control module for controlling leakage detection and a leakage sensing module for detecting leakage. The leakage sensing modules are provided with several groups, and the number of the leakage sensing modules corresponds to the number of channels of the multi-channel control modules. The multi-channel control modules are provided with several groups, and several groups of the multi-channel control modules are connected to the main controller module. The leakage sensing module includes a leakage sensing unit, a starting connection unit and a terminal connection unit. The two ends of the leakage sensing unit are respectively connected to the starting connection unit and the terminal connection unit, and the starting connection unit is connected to the multi-channel control module.

2. According to the online monitoring system for water leakage of low-temperature economizer in flue gas deep waste heat recovery system of claim 1, it is characterized by: The liquid leakage sensing unit comprises a liquid leakage sensor and a liquid leakage sensing plate, and the liquid leakage sensor is mounted on the liquid leakage sensing plate.

3. The online monitoring system for water leakage of low-temperature economizer in a flue gas deep waste heat recovery system according to claim 2 is characterized by: The liquid leakage sensor is in the form of a sensing strip, the material of the sensing strip is polytetrafluoroethylene, and the leakage judgment basis of the liquid leakage sensor is the current size.

4. The online monitoring system for water leakage of low-temperature economizer in a flue gas deep waste heat recovery system according to claim 1 is characterized in that: The multi-channel control module has two detection modes: liquid leakage and sensor membrane damage.

5. The online monitoring system for water leakage of low-temperature economizer in a flue gas deep waste heat recovery system according to claim 1 is characterized by: The leakage monitoring layer also includes an acoustic and visual alarm module, and the input end of the acoustic and visual alarm module is connected to the output end of the liquid leakage sensing module.

6. The online monitoring system for water leakage of low-temperature economizer in a flue gas deep waste heat recovery system according to claim 5 is characterized by: The warning levels of the sound and light alarm module are divided into three levels: normal, leakage and rupture, and each level provides different lights and sounds.

7. The online monitoring system for water leakage of low-temperature economizer in a flue gas deep waste heat recovery system according to claim 1 is characterized by: The central control module includes an operating platform unit, a data storage unit and a graphic display unit.

8. The online monitoring system for water leakage of low-temperature economizer in a flue gas deep waste heat recovery system according to claim 2 is characterized by: The surface roughness of the liquid leakage sensor is Ra<0.

2.

9. The online monitoring system for water leakage of low-temperature economizer in a flue gas deep waste heat recovery system according to claim 2 is characterized by: The sensing belt is provided with detection holes, and the detection holes are provided in a plurality of groups, and the detection holes in the plurality of groups are spaced 10 mm apart.

10. The online monitoring system for water leakage of low-temperature economizer in a flue gas deep waste heat recovery system according to claim 1, characterized in that: A leakage determination threshold value A is preset in the multi-channel control module, and the leakage determination threshold values ​​A corresponding to each group of the leakage sensing modules are inconsistent, and the leakage determination threshold value A is ≥ 1KΩ.

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