Heat exchanger internal process gas leak detection system

Abstract

The utility model discloses heat exchanger internal process gas leak detection system, including heat exchanger, the condensate water export of heat exchanger is connected with gas -liquid separator through pipeline, and the gas in the gas -liquid separator is connected with rotor flowmeter through pipeline along the upper portion of gas -liquid separator, and rotor flowmeter is connected to torch place and venting place through pipeline, and the liquid in the gas -liquid separator is discharged to the recovery unit through pipeline along the bottom of gas -liquid separator, heat exchanger is distributed with several temperature sensors along the heat exchange medium flow path, and several temperature sensors are connected to host computer through wireless transmission device, and host computer is also connected with rotor flowmeter through circuit. The utility model has solved the problem of the existing technology for heat exchanger internal process gas leak detection lag.

Description

Technical Field

[0001] This utility model belongs to the field of methanol production process technology, specifically relating to a process gas leakage detection system inside a heat exchanger. Background Technology

[0002] In industrial production, heat exchangers, as key equipment for achieving heat exchange between materials, are widely used in chemical, energy and other fields. Their internal components often involve the transmission and heat exchange of toxic and flammable process gases (such as hydrogen). To ensure the safe operation of the equipment, it is necessary to detect potential leaks in the heat exchanger tubes in a timely manner. Current technologies mostly rely on a four-in-one alarm device to monitor leaks at the high-point exhaust valve on the low-pressure side of the heat exchanger.

[0003] However, this detection method has significant limitations: on the one hand, due to limitations in the detection location and the response characteristics of the alarm, it is difficult to accurately capture the leak signal at the first moment of the leak, making it difficult to detect the leak in its early stages; on the other hand, if the toxic gases produced by the leak are not detected in time, they can easily spread to the working environment, causing the risk of poisoning to on-site workers; at the same time, the leaked gases (especially flammable gases such as hydrogen) cannot be discharged in a timely and effective manner through existing methods, and can easily accumulate in large quantities around the equipment, forming safety hazards such as explosions and fires, seriously threatening production safety and personnel health.

[0004] Therefore, in order to meet the need for efficient and accurate detection of process gas leaks inside heat exchangers, there is an urgent need for a detection system that can overcome the limitations of existing technologies to solve problems such as delayed leak detection and prominent safety hazards. Utility Model Content

[0005] The purpose of this invention is to provide a process gas leakage detection system inside a heat exchanger, which solves the problem of lagging detection of process gas leakage inside heat exchangers in the prior art.

[0006] The technical solution adopted in this utility model is a process gas leakage detection system inside a heat exchanger, including a heat exchanger. The condensate outlet of the heat exchanger is connected to a gas-liquid separator through a pipeline. The gas inside the gas-liquid separator is connected to a rotor flow meter through a pipeline along the upper part of the gas-liquid separator. The rotor flow meter is connected to a flare and a vent through a pipeline. The liquid inside the gas-liquid separator is discharged to a recovery unit through a pipeline along the bottom of the gas-liquid separator.

[0007] Several temperature sensors are distributed along the flow path of the heat exchange medium inside the heat exchanger. These temperature sensors are connected to a host computer via a wireless transmission device. The host computer is also connected to a rotor flow meter via a line.

[0008] The present invention is further characterized in that,

[0009] The two ends of the connecting pipeline between the heat exchanger and the gas-liquid separator are sealed to the heat exchanger and the gas-liquid separator respectively through flanges.

[0010] A separator inlet valve is installed on the connecting pipeline between the heat exchanger and the gas-liquid separator.

[0011] A flare valve is installed on the pipeline connecting the rotor flowmeter to the flare, and a vent valve is installed on the pipeline connecting the rotor flowmeter to the vent.

[0012] The vent is connected to a nitrogen supply line, which is used to purge the gas discharged into the vent.

[0013] The host computer is also connected to a PLC controller. The PLC controller is connected to the switches of the flare valve, vent valve and heat exchanger through lines. The PLC controller opens and closes the flare valve, vent valve and heat exchanger according to the leakage detected by the rotor flow meter.

[0014] A separator exhaust valve is installed on the pipe connecting the gas-liquid separator and the rotor flow meter, and a separator drain valve is installed on the pipe connecting the gas-liquid separator and the recovery unit.

[0015] Several temperature sensors are distributed at equal intervals along the flow path of the heat exchange medium, and the temperature sensors are fixed to the inner wall of the heat exchanger shell.

[0016] The heat exchanger has a process gas inlet and a process gas outlet on the upper and lower sides of one end, respectively, and a flow baffle is installed between them. The process gas enters the heat exchanger from the process gas inlet, flows through the tube array, and then flows to the process gas outlet.

[0017] The heat exchanger has a condensate inlet located below the tube set, and a condensate outlet located above the tube set.

[0018] The beneficial effects of this utility model are:

[0019] (1) The process gas leakage detection system inside the heat exchanger of this utility model connects a gas-liquid separator to the condensate outlet of the heat exchanger, so that the gas-liquid mixture formed by the leaked process gas and condensate directly enters the separator for separation. The flow rate of the separated gas phase is monitored in real time by a rotor flow meter. At the same time, temperature sensors are set at equal intervals along the flow path of the heat exchange medium on the inner wall of the heat exchanger shell to capture the local temperature rise caused by the mixing of high-temperature process gas in real time. "Direct gas-liquid separation + real-time flow monitoring" avoids the time loss of leaked gas diffusing to the fixed detection point. With the help of "temperature anomaly capture + flow data linkage", early identification of leakage signals is achieved. It can respond quickly without waiting for the gas concentration to accumulate, thus solving the problem of delayed leakage detection caused by the reliance on four-in-one alarm detection in the prior art.

[0020] (2) The heat exchanger internal process gas leakage detection system of this utility model fixes temperature sensors at equal intervals along the flow path of the heat exchange medium on the inner wall of the heat exchanger shell, so that the sensors directly contact the heat exchange medium. When a leak occurs in the tube, the high-temperature process gas mixes with the low-temperature heat exchange medium, which will cause a sudden increase in local temperature downstream of the leak point. The temperature sensor at a specific location can accurately detect this anomaly. By utilizing the distributed layout and direct contact characteristics of the temperature sensors, the flow section of the heat exchange medium where the leak is located can be locked by the location of the abnormal temperature sensor, providing a clear range for leak point investigation and realizing rapid location of the leak. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the internal process gas leakage detection system of the heat exchanger of this utility model.

[0022] In the diagram, 1. Heat exchanger, 2. Gas-liquid separator, 3. Rotor flow meter, 4. Flange, 5. Separator inlet valve, 6. Separator exhaust valve, 7. Flare valve, 8. Vent valve, 9. Separator drain valve, 10. Process gas inlet, 11. Process gas outlet, 12. Condensate inlet, 13. PLC controller, 14. Condensate outlet, 15. Separator inlet, 16. Separator drain outlet, 17. Separator exhaust outlet, 18. Temperature sensor, 19. Wireless transmission device, 20. Host computer. Detailed Implementation

[0023] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0024] Currently, existing technologies often use four-in-one alarms to monitor process gas leaks inside heat exchangers. However, these alarms are usually installed in fixed locations such as the high-point exhaust valve on the low-pressure side of the heat exchanger. In the early stages of a leak, the amount of leaked process gas is extremely small, and the leaked process gas dissolves in the condensate of the heat exchanger, making it impossible for the four-in-one alarm to detect the leak. By the time the leaked process gas concentration reaches the detection point, the leak often needs to accumulate to a certain concentration before triggering the alarm, resulting in an inability to respond to the leak in the first instance and missing the opportunity for early intervention.

[0025] In addition, the four-in-one alarm is mainly designed for conventional combustible gases (such as methane) and toxic gases (such as carbon monoxide and hydrogen sulfide). It may not be sensitive to process gases specific to heat exchangers (such as mixed gases of specific components or low-concentration special gases), or may even fail to detect them effectively, resulting in a "coverage blind spot".

[0026] Meanwhile, the four-in-one alarm system only has an alarm function and cannot trigger emergency measures such as gas emission or equipment shutdown. Even if an alarm is triggered, the leaked toxic gas may continue to spread, increasing the risk of poisoning; and flammable gases such as hydrogen may accumulate due to the inability to be emitted in time, exacerbating the risk of explosion and combustion.

[0027] Therefore, this utility model provides a process gas leakage detection system inside a heat exchanger to solve the above problems, as shown in the following embodiments.

[0028] Example 1

[0029] This utility model relates to a heat exchanger internal process gas leakage detection system, such as... Figure 1 As shown, the core detection object is heat exchanger 1. When heat exchanger 1 is running, the high-temperature process gas inside exchanges heat with the low-temperature heat exchange medium through the tubes. When tube leakage or other problems occur inside heat exchanger 1, the process gas will enter the heat exchange medium, forming a gas-liquid mixture. This mixture flows with the heat exchange medium to the condensate outlet 14 of heat exchanger 1, and then is transported to the gas-liquid separator 2 through a dedicated pipeline.

[0030] The gas-liquid separator 2 plays a crucial role in gas-liquid separation. The gas-liquid mixture entering the separator is separated inside: the liquid part collects at the bottom of the gas-liquid separator 2 due to gravity, and is then discharged to the recovery unit through a pipeline. This avoids the waste and risks caused by the direct discharge of liquid containing process gas, and facilitates subsequent centralized treatment; the gas part rises along the upper part of the gas-liquid separator 2 and is connected to the rotor flow meter 3 through a pipeline, which monitors the gas flow rate in real time.

[0031] The outlet of the rotor flowmeter 3 is connected to the flare and the vent via pipelines, respectively. Different discharge paths can be selected according to the gas flow rate: when the flow rate is small, the gas can be safely discharged through the vent; when the flow rate reaches a certain level, it is switched to the flare for treatment to ensure the safety of the gas discharge process.

[0032] To improve the timeliness and accuracy of leak detection, several temperature sensors 18 are distributed along the flow path of the heat exchange medium inside the heat exchanger 1. These temperature sensors 18 can sense the temperature changes of the heat exchange medium in real time. Under normal operating conditions, the temperature of the heat exchange medium exhibits a stable gradient change; when a process gas leak occurs, the high-temperature process gas mixed into the heat exchange medium will cause local temperature anomalies, and the temperature sensors 18 can quickly capture this change.

[0033] Temperature data collected by several temperature sensors 18 is transmitted to a host computer 20 via a wireless transmission device 19, enabling wireless data transmission and real-time aggregation. Simultaneously, the host computer 20 is connected to a rotor flow meter 3 via a line, synchronously receiving gas flow data monitored by the rotor flow meter 3. The host computer 20 performs comprehensive analysis of the temperature and flow data. When an abnormal temperature change occurs and the flow rate simultaneously shows gas passing through, it can accurately determine that a process gas leak has occurred inside the heat exchanger 1, thereby promptly triggering the corresponding handling mechanism and effectively improving the efficiency and reliability of leak detection.

[0034] Example 2

[0035] This utility model relates to a heat exchanger internal process gas leakage detection system, such as... Figure 1 As shown, it includes a heat exchanger 1. A process gas inlet 10 and a process gas outlet 11 are respectively provided on the upper and lower sides of one end of the heat exchanger 1. A stroke baffle is provided between the two. The process gas enters the heat exchanger 1 from the process gas inlet 10, flows through the tube array and then flows to the process gas outlet 11.

[0036] The heat exchanger 1 has a condensate inlet 12 located below the tube array and a condensate outlet 14 located above the tube array.

[0037] The condensate outlet 14 of heat exchanger 1 is connected to the separator inlet 15 of gas-liquid separator 2 through a pipeline. The gas inside gas-liquid separator 2 is connected to rotor flow meter 3 through a pipeline along the separator exhaust port 17 at the top of gas-liquid separator 2. The rotor flow meter 3 is connected to the flare and vent through a pipeline. The liquid inside gas-liquid separator 2 is discharged to the recovery unit through a pipeline along the separator drain port 16 at the bottom of gas-liquid separator 2.

[0038] Several temperature sensors 18 are distributed along the flow path of the heat exchange medium inside the heat exchanger 1. The temperature sensors 18 are connected to the host computer 20 through a wireless transmission device 19. The host computer 20 is also connected to the rotor flow meter 3 through a line.

[0039] Furthermore, the connecting pipeline between heat exchanger 1 and gas-liquid separator 2 is sealed at both ends through flanges 4 to the condensate outlet 14 of heat exchanger 1 and the inlet of gas-liquid separator 2, respectively. The flanges 4 adopt a standard structure adapted to the pipeline specifications. Evenly distributed bolt groups tightly fit the flange faces at both ends of the pipeline. Combined with sealing gaskets (such as corrosion-resistant rubber gaskets or spiral wound gaskets) between the flange faces, leakage paths of the gas-liquid mixture during transmission can be effectively blocked—ensuring that all the gas-liquid mixture flowing from heat exchanger 1 enters the pipeline, while avoiding environmental risks and detection errors caused by spillage at the connection points. This provides a sealed and reliable medium transmission channel for subsequent gas-liquid separation and flow monitoring.

[0040] A separator inlet valve 5 is specifically installed on the connecting pipeline between heat exchanger 1 and gas-liquid separator 2. This valve is located on the side of the pipeline closer to the inlet of gas-liquid separator 2 and is normally kept open, allowing the gas-liquid mixture flowing from heat exchanger 1 to smoothly enter gas-liquid separator 2 through the pipeline. When it is necessary to inspect or maintain heat exchanger 1 or gas-liquid separator 2, or in case of an emergency, the separator inlet valve 5 can be closed to cut off the pipeline passage and prevent the medium from continuing to flow into the separator. This not only avoids medium leakage during maintenance but also achieves independent isolation between the heat exchanger and the separator, providing safe operating conditions for equipment maintenance or fault handling, while not affecting the temporary operation and adjustment of other parts of the system.

[0041] Example 3

[0042] Based on Embodiment 2 above, this embodiment features a flare valve 7 on the connecting pipe between the rotor flowmeter 3 and the flare, and a vent valve 8 on the connecting pipe between the rotor flowmeter 3 and the vent. These two valves correspond to different gas emission paths and are normally linked for control based on the leakage rate monitored by the rotor flowmeter 3: when the leakage is small, the vent valve 8 opens and the flare valve 7 closes, allowing the gas to be discharged through the vent; when the leakage reaches a preset threshold, the vent valve 8 closes and the flare valve 7 opens, switching the gas to the flare for processing. The precise opening and closing of the valves ensures that leaked gas of different magnitudes can be safely discharged through the appropriate path, avoiding safety risks caused by improper discharge methods, and providing stable medium flow guidance for flow monitoring.

[0043] The vent is connected to a dedicated nitrogen supply pipeline, which continuously supplies nitrogen to the gas being discharged. As an inert gas, nitrogen effectively purges the gas discharged to the vent – ​​by diluting the process gas concentration, it reduces the concentration of process gas in the discharged gas, preventing it from accumulating around the vent and forming a hazardous area. Simultaneously, the flow of nitrogen promotes rapid diffusion of the discharged gas, reducing the residence time of process gas in the local environment and further ensuring the safety of the on-site working environment, making it particularly suitable for handling leaks of toxic or flammable process gases.

[0044] The host computer 20 is also connected to the PLC controller 13, forming an automated closed loop of "monitoring-analysis-control". The PLC controller 13 is connected to the switches of the flare valve 7, the vent valve 8, and the heat exchanger 1 via lines, and can receive the detection data of the rotor flow meter 3 transmitted by the host computer 20 in real time. When the rotor flow meter 3 detects a leak, the PLC controller 13 automatically executes operations according to the preset flow threshold: when the leak is less than 5 kg / h, it controls the vent valve 8 to open and the flare valve 7 to close, while maintaining the normal operation of the heat exchanger 1; when the leak is greater than 5 kg / h but less than 15 kg / h, it switches to opening the flare valve 7 and closing the vent valve 8, and simultaneously issues a warning signal; when the leak increases to 15 kg / h, it immediately controls the flare valve 7 to open and simultaneously closes the switch of the heat exchanger 1, cutting off the process gas supply. This automated control mechanism requires no manual intervention, can respond quickly after a leak occurs, significantly shortens the time from detection to handling, effectively reduces the risk of leak expansion, and improves the safety protection level of the system.

[0045] Example 4

[0046] Based on Embodiment 3 above, this embodiment features a separator exhaust valve 6 on the connecting pipe between the gas-liquid separator 2 and the rotor flowmeter 3. This valve is located in the connection path between the upper gas phase outlet of the gas-liquid separator 2 and the rotor flowmeter 3, and is a key component for regulating the flow direction of the gas phase medium. Under normal conditions, the separator exhaust valve 6 remains open, allowing the gas separated by the gas-liquid separator 2 to smoothly enter the rotor flowmeter 3, ensuring continuous flow monitoring. When maintenance is required on the gas-liquid separator 2 or the rotor flowmeter 3 (such as cleaning internal impurities or calibrating flowmeter accuracy), the separator exhaust valve 6 can be closed to cut off the gas phase flow path, preventing gas leakage and providing a safe operating space for equipment maintenance. Simultaneously, by fine-tuning the valve opening, the airflow velocity entering the rotor flowmeter 3 can be stabilized, reducing flow detection errors caused by airflow fluctuations and ensuring data accuracy.

[0047] A separator drain valve 9 is installed on the pipeline connecting the gas-liquid separator 2 to the recovery unit. This valve is located on the connecting pipeline between the liquid phase outlet at the bottom of the gas-liquid separator 2 and the recovery unit, and it is responsible for controlling the liquid discharge. During normal operation, the separator drain valve 9 opens in a timely manner according to the liquid level in the gas-liquid separator 2, so that the separated liquid (including a small amount of condensate containing dissolved process gas) is discharged into the recovery unit in an orderly manner. This avoids excessive accumulation of liquid in the separator, which affects the separation efficiency, and also realizes centralized recovery and treatment of liquid containing process gas. When the recovery unit needs to be repaired or the liquid discharge path needs to be changed, the separator drain valve 9 can be closed to temporarily block the liquid discharge, prevent the environmental risks caused by liquid leakage, and facilitate the cleaning or maintenance of the separator, ensuring the stability and controllability of the liquid phase treatment process.

[0048] Furthermore, several temperature sensors 18 are evenly distributed along the flow path of the heat exchange medium inside the heat exchanger 1 shell. This distribution method can comprehensively cover the entire flow process of the heat exchange medium, forming a continuous temperature monitoring gradient—from the heat exchange medium inlet to the outlet, each segment of the path has a sensor to capture temperature changes in real time, avoiding the omission of leakage signals due to sparse monitoring points. The temperature sensors 18 are fixed to the inner wall of the heat exchanger 1 shell and are in direct contact with the heat exchange medium (such as condensate) in the shell side, which can minimize the temperature response time: when a leak occurs in the tube, the high-temperature process gas mixed into the heat exchange medium will cause a sudden increase in local temperature. The sensor close to the inner wall can capture this anomaly immediately, reducing heat conduction loss compared to external sensors and significantly improving the sensitivity of temperature detection.

[0049] The combination of equidistant distribution and fixed inner wall design enables temperature sensor 18 to not only comprehensively monitor the temperature field distribution of the heat exchange medium, but also accurately locate abnormal temperature areas. By comparing the temperature difference between adjacent sensors, the approximate section where the leak point is located can be quickly identified, providing a key basis for subsequent judgment of the leak location based on flow data, and further improving the system's ability to identify and locate leaks in the early stages.

[0050] Example 5

[0051] The heat exchanger internal process gas leakage detection system of this utility model also includes an alarm device. The control terminal of the alarm device is connected to the output terminal of the host computer 20. The alarm device is used to respond to the alarm according to the instruction of the host computer 20 when a leak occurs in the tube. The alarm device can be an audible and visual alarm or other alarm devices.

[0052] Example 6

[0053] The heat exchanger internal process gas leakage detection system of this utility model also includes a display device. The control terminal of the display device is connected to the output terminal of the host computer 20. The display device is used to display the temperature measured by each temperature sensor 18 in real time according to the instructions of the host computer 20. The host computer 20 determines whether a pipeline leak has occurred based on the measurement data of the temperature sensors 18, and then displays the status of the pipeline in real time.

[0054] Example 7

[0055] The heat exchanger internal process gas leakage detection system of this utility model also includes a timer, which is connected to the host computer 20. The host computer 20 is used to control the temperature sensor to monitor the tube under monitoring at regular intervals according to the timer.

[0056] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0057] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0058] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A process gas leakage detection system inside a heat exchanger, characterized in that, The heat exchanger (1) is connected to the condensate outlet (14) of the heat exchanger (1) via a pipeline to a gas-liquid separator (2). The gas inside the gas-liquid separator (2) is connected to a rotor flow meter (3) via a pipeline along the upper part of the gas-liquid separator (2). The rotor flow meter (3) is connected to the flare and the vent via a pipeline. The liquid inside the gas-liquid separator (2) is discharged to the recovery unit via a pipeline along the bottom of the gas-liquid separator (2). Several temperature sensors (18) are distributed along the flow path of the heat exchange medium inside the heat exchanger (1). The temperature sensors (18) are connected to the host computer (20) through a wireless transmission device (19). The host computer (20) is also connected to the rotor flow meter (3) through a line.

2. The heat exchanger internal process gas leakage detection system according to claim 1, characterized in that, The two ends of the connecting pipes of the heat exchanger (1) and the gas-liquid separator (2) are respectively sealed to the heat exchanger (1) and the gas-liquid separator (2) through flanges (4).

3. The heat exchanger internal process gas leakage detection system according to claim 2, characterized in that, A separator inlet valve (5) is provided on the connecting pipe between the heat exchanger (1) and the gas-liquid separator (2).

4. The heat exchanger internal process gas leakage detection system according to claim 1, characterized in that, A flare valve (7) is installed on the pipeline connecting the rotor flowmeter (3) and the flare, and a vent valve (8) is installed on the pipeline connecting the rotor flowmeter (3) and the vent. The vent is connected to a nitrogen supply line, which is used to purge the gas discharged into the vent.

5. The heat exchanger internal process gas leakage detection system according to claim 4, characterized in that, The host computer (20) is also connected to a PLC controller (13). The PLC controller (13) is connected to the switches of the flare valve (7), the vent valve (8) and the heat exchanger (1) respectively through the lines. The PLC controller (13) performs opening and closing operations on the flare valve (7), the vent valve (8) and the heat exchanger (1) respectively according to the leakage detected by the rotor flow meter (3).

6. The heat exchanger internal process gas leakage detection system according to claim 1, characterized in that, A separator exhaust valve (6) is provided on the pipe connecting the gas-liquid separator (2) and the rotor flow meter (3), and a separator drain valve (9) is provided on the pipe connecting the gas-liquid separator (2) and the recovery unit.

7. The heat exchanger internal process gas leakage detection system according to claim 1, characterized in that, Several temperature sensors (18) are distributed at equal intervals along the flow path of the heat exchange medium, and the temperature sensors (18) are fixed to the inner wall of the heat exchanger (1) shell.

8. The heat exchanger internal process gas leakage detection system according to claim 1, characterized in that, The heat exchanger (1) has a process gas inlet (10) and a process gas outlet (11) on the upper and lower sides of one end, respectively. A flow partition is provided between the two. The process gas enters the heat exchanger (1) from the process gas inlet (10), flows through the tube array, and then flows to the process gas outlet (11). The heat exchanger (1) has a condensate inlet (12) located below the tube array and a condensate outlet (14) located above the tube array.

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