Intelligent purging device for differential pressure measuring pipeline of mist eliminator

Abstract

The utility model belongs to the wet flue gas desulfurization technical field, concretely relates to a kind of intelligent purging device of mist eliminator differential pressure measuring pipeline, mist eliminator differential pressure measurement transmitter is communicated with mist eliminator high pressure pressure guide pipe, mist eliminator low pressure pressure guide pipe respectively, positive pressure side pipeline shut-off solenoid valve is set on mist eliminator high pressure pressure guide pipe, negative pressure side pipeline shut-off solenoid valve is set on mist eliminator low pressure pressure guide pipe, mist eliminator high pressure pressure guide pipe is connected with flow low switch by positive pressure side pipeline purging solenoid valve, mist eliminator low pressure pressure guide pipe is connected with flow low switch by negative pressure side pipeline purging solenoid valve, flow low switch is connected with compressed air pipeline by compressed air manual ball valve.The intelligent purging device of mist eliminator differential pressure measuring pipeline provided by the utility model is innovatively designed by hardware structure and intelligent control logic, effectively solve the problems, such as low degree of automation, sweeping strategy extensive, insufficient fault diagnosis capability etc.

Description

Technical Field

[0001] This utility model belongs to the field of wet flue gas desulfurization technology, specifically relating to an intelligent purging device for differential pressure measurement pipeline of a demister. Background Technology

[0002] In industrial production, especially in limestone-gypsum wet flue gas desulfurization systems, demisters are crucial equipment. Their function is to remove mist droplets carried in the flue gas to ensure the safe operation of downstream equipment. Differential pressure measurement of the demister is a key aspect of monitoring its operating status. Accurate differential pressure data can reflect the demister's clogging status and operating efficiency, providing a basis for stable system control.

[0003] However, in actual operation, the high-pressure and low-pressure guide pipes of the demister are easily contaminated by impurities such as gypsum slurry and dust in the flue gas, leading to pipe blockage and consequently causing inaccurate or even malfunctioning differential pressure measurements. Once the guide pipes are blocked, it will not only affect the real-time monitoring of the demister's operating status but may also cause misjudgments in the control system, threatening the safe and stable operation of the entire desulfurization system.

[0004] Existing differential pressure measurement pipeline purging technologies have significant shortcomings. Traditional manual purging methods require operators to frequently check the pipeline status and manually activate the purging device, which is labor-intensive and slow to respond, making it difficult to remove impurities in the initial accumulation stage, easily leading to a gradual worsening of blockages. While some automated purging devices achieve timed purging, they lack real-time monitoring and intelligent judgment of differential pressure data, which may result in over-purging or under-purging: over-purging wastes compressed air resources and increases energy consumption; under-purging fails to effectively remove impurities from the pipeline, resulting in persistent measurement errors.

[0005] Furthermore, existing technologies offer limited flow monitoring and alarm functions for the purging process. When compressed air flow is insufficient or persistent blockages occur in the pipeline, they cannot promptly issue alarms or take appropriate action, further impacting the reliability of the differential pressure measurement system. Simultaneously, traditional devices suffer from deficiencies in electrical control and logic algorithms, failing to accurately control the purging process based on the dynamic trends of differential pressure changes. They also struggle to evaluate and provide feedback on the purging effect, resulting in a low level of intelligence across the entire purging system. Utility Model Content

[0006] To address the technical problems existing in the purging of differential pressure measurement pipelines in demisters, this utility model provides an intelligent purging device for differential pressure measurement pipelines in demisters.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows:

[0008] A smart purging device for a demister differential pressure measurement pipeline includes a low flow switch, a positive pressure side pipeline purging solenoid valve, a negative pressure side pipeline purging solenoid valve, a positive pressure side pipeline shut-off solenoid valve, a negative pressure side pipeline shut-off solenoid valve, a demister differential pressure measurement transmitter, a compressed air manual ball valve, a demister high-pressure guide pipe, and a demister low-pressure guide pipe. The demister differential pressure measurement transmitter is connected to both the demister high-pressure guide pipe and the demister low-pressure guide pipe. The positive pressure side pipeline shut-off solenoid valve is located on the demister high-pressure guide pipe, and the negative pressure side pipeline shut-off solenoid valve is located on the demister low-pressure guide pipe. The demister high-pressure guide pipe is connected to the low flow switch via the positive pressure side pipeline purging solenoid valve, and the demister low-pressure guide pipe is connected to the low flow switch via the negative pressure side pipeline purging solenoid valve. The low flow switch is connected to the compressed air pipeline via the compressed air manual ball valve.

[0009] The positive pressure side pipeline purging solenoid valve, negative pressure side pipeline purging solenoid valve, positive pressure side pipeline shut-off solenoid valve, and negative pressure side pipeline shut-off solenoid valve are all electrically connected to the local control box electrical circuit.

[0010] The local control box electrical circuit includes an air switch, a fuse, a timer, a start-purge intermediate relay, a DCS start switch, a low flow switch, and a low purge flow alarm output relay. The air switch is electrically connected to the fuse, the fuse is electrically connected to the coil of the timer, the timer coil is electrically connected to the air switch, the fuse is electrically connected to the normally open contact of the timer, the normally open contact of the timer is electrically connected to the coil of the start-purge intermediate relay, the start-purge intermediate relay coil is electrically connected to the air switch, the DCS start switch is connected in parallel across the normally open contact of the timer, the fuse is electrically connected to the first normally open contact of the start-purge intermediate relay, the first normally open contact of the start-purge intermediate relay is electrically connected to the low flow switch, the low flow switch is electrically connected to the coil of the low purge flow alarm output relay, and the low purge flow alarm output relay coil is electrically connected to the air switch.

[0011] The fuse is electrically connected to the second normally open contact of the start-purge intermediate relay, and the second normally open contact of the start-purge intermediate relay is electrically connected to the relay of the positive pressure side pipeline purge solenoid valve.

[0012] The fuse is electrically connected to the third normally open contact of the start-purge intermediate relay, and the third normally open contact of the start-purge intermediate relay is electrically connected to the relay of the negative pressure side pipeline purge solenoid valve.

[0013] The fuse is electrically connected to the fourth normally open contact of the intermediate relay for starting the purge, and the fourth normally open contact of the intermediate relay for starting the purge is electrically connected to a relay for shutting off the solenoid valve on the positive pressure side pipeline.

[0014] The fuse is electrically connected to the fifth normally open contact of the start-purge intermediate relay, and the fifth normally open contact of the start-purge intermediate relay is electrically connected to a relay for shutting off the solenoid valve of the negative pressure side pipeline.

[0015] The DCS start switch is electrically connected to the DCS logic control module.

[0016] The DCS logic control module includes a high-limit monitoring algorithm unit, a single-pulse algorithm unit, and a low purge flow indicator alarm unit. The input of the high-limit monitoring algorithm unit is connected between the high-pressure and low-pressure guide pipes of the demister. The threshold of the high-limit monitoring algorithm unit is set to 35 Pa. When the input differential pressure measurement value exceeds this threshold, its output triggers the single-pulse algorithm unit. The single-pulse algorithm unit is set to 4 minutes, and its output is connected to the DCS start switch to output a continuous 4-minute start purge signal. The coil of the low purge flow alarm output relay is connected to the low purge flow indicator alarm unit.

[0017] The DCS logic control module further includes a lead-lag algorithm unit, a subtractor algorithm unit, a low-limit monitoring algorithm unit, a logic AND algorithm unit, a start-purge switch input point, a delay-closing algorithm unit, a delay-opening algorithm unit, and a stubborn blockage alarm unit. The input of the lead-lag algorithm unit is connected between the high-pressure and low-pressure guide pipes of the demister. The threshold of the lead-lag algorithm unit is set to 4 minutes. The output of the lead-lag algorithm unit is connected to the input of the subtractor algorithm unit to calculate the differential pressure difference before and after purging. The output of the subtractor algorithm unit is connected to the low-limit monitoring unit. The input terminal of the algorithm unit is connected to the input terminal of the logic AND algorithm unit, where the threshold of the low-limit monitoring algorithm unit is set to 10 Pa. The output terminal of the low-limit monitoring algorithm unit is connected to the input terminal of the logic AND algorithm unit. The input terminal of the start-purge switch input point is connected to the input terminal of the delay-closing algorithm unit, where the threshold is set to 4 min. The output terminal of the delay-closing algorithm unit is connected to the input terminal of the delay-opening algorithm unit, where the threshold is set to 10 s. The output terminal of the delay-opening algorithm unit is connected to the input terminal of the logic AND algorithm unit, and the output terminal of the logic AND algorithm unit is connected to a persistent blockage alarm unit.

[0018] Compared with the prior art, the advantages of this utility model are:

[0019] 1. The intelligent purging device for differential pressure measurement pipelines of demisters provided by this utility model effectively solves the problems of low automation, coarse purging strategies, and insufficient fault diagnosis capabilities of traditional purging devices through innovative design of hardware structure and intelligent control logic. The device monitors the differential pressure value of the high and low pressure guide pipes of the demister in real time through the high limit monitoring algorithm unit in the DCS logic control module. When the differential pressure exceeds the set threshold, the single pulse algorithm unit is automatically triggered to output a continuous purging signal. This mechanism of dynamically starting purging according to the actual degree of pipeline blockage avoids the blindness of traditional timed purging, prevents the waste of compressed air caused by over-purging, and eliminates measurement failure caused by failure to purge in time due to severe blockage. It makes the purging operation accurately match the pipeline contamination state, significantly improving the real-time performance and reliability of the differential pressure measurement system.

[0020] 2. The low flow switch and the low purge flow alarm output relay of this utility model form a monitoring circuit to detect the compressed air purge flow in real time. When the flow is insufficient, an alarm is immediately issued through the light-up alarm unit to avoid ineffective purging due to insufficient air source pressure or pipeline leakage. At the same time, the differential pressure value before and after purging is calculated by the lead-lag algorithm unit and the subtractor algorithm unit. Combined with the delayed closing / opening algorithm logic, it can determine whether there is a stubborn blockage in the pipeline and trigger an alarm, providing a clear fault location signal for manual intervention and solving the defect of no feedback on the purging effect of traditional devices.

[0021] 3. This utility model integrates two modes: local control box electrical circuit and DCS remote control. Local control achieves periodic automatic purging through timers, meeting the needs of conventional operation scenarios. DCS remote control allows the host computer to flexibly intervene in the purging strategy according to the system's operating status. The two modes control the positive and negative pressure side purging solenoid valves and shut-off solenoid valves respectively through the activation of multiple normally open contacts of the purging intermediate relay, ensuring reliable isolation between the pressure guide pipe and the differential pressure transmitter during purging, avoiding damage to the measuring elements by compressed air impact, and improving the safety and control flexibility of the device operation.

[0022] 4. The intelligent logic algorithm of this utility model accurately controls the timing and duration of purging, which can reduce a large amount of compressed air consumption and lower energy costs compared with traditional timed purging. The multiple algorithm units of the DCS logic control module construct a fully closed-loop intelligent control system, which can realize the self-maintenance of differential pressure measurement pipeline without frequent manual inspections, and improve the automation level of the purging device from mechanical timing to data-driven decision-making, thus completing the intelligent upgrade.

[0023] 5. The modular design of the positive and negative pressure side pipeline shut-off solenoid valve and the purging solenoid valve of this utility model completely isolates the pressure guide pipe from the measurement circuit during purging, preventing impurities from backflowing and contaminating the transmitter during the purging process; the compressed air manual ball valve serves as a backup interface to support manual air replenishment during online maintenance, ensuring that the device can still maintain basic purging function when some components fail. The overall structure is simple and has high functional redundancy, reducing maintenance complexity and extending the mean time between failures of the differential pressure measurement system. Attached Figure Description

[0024] To more clearly illustrate the embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0025] The structures, proportions, sizes, etc. illustrated in this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed herein, and are not intended to limit the implementation conditions of this utility model. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportional relationships, or adjustments to the size, without affecting the effects and purposes that this utility model can produce, should still fall within the scope of the technical content disclosed in this utility model.

[0026] Figure 1 This is a schematic diagram of the local gas path of this utility model;

[0027] Figure 2 This is the electrical circuit diagram of the local control box of this utility model;

[0028] Figure 3 This is a schematic diagram of the DCS logic control module of this utility model.

[0029] Wherein: FS is the low flow switch, 2 is the positive pressure side pipeline purge solenoid valve, 3 is the negative pressure side pipeline purge solenoid valve, 4 is the positive pressure side pipeline shut-off solenoid valve, 5 is the negative pressure side pipeline shut-off solenoid valve, 6 is the demister differential pressure measuring transmitter, 7 is the compressed air manual ball valve, P+ is the demister high-pressure guide pipe, P- is the demister low-pressure guide pipe, QF1 is the air switch, FU is the fuse, KT is the timer, K1 is the start purge intermediate relay, and DCS is the DCS... Start switch, K2 is the low purge flow alarm output relay, 8 is the high limit monitoring algorithm unit, 9 is the single pulse algorithm unit, 10 is the low purge flow light alarm unit, 11 is the lead-lag link algorithm unit, 12 is the subtractor algorithm unit, 13 is the low limit monitoring algorithm unit, 14 is the logic AND algorithm unit, 15 is the start purge switch input point, 16 is the delay closing algorithm unit, 17 is the delay opening algorithm unit, and 18 is the stubborn blockage alarm unit. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions in the embodiments of this utility model will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. These descriptions are only for further illustrating the features and advantages of this utility model, and not for limiting the claims of this utility model. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0031] The specific embodiments of this utility model will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this utility model, but are not intended to limit its scope.

[0032] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0033] This embodiment provides an intelligent purging device for the differential pressure measurement pipeline of a demister, such as... Figure 1As shown, T-joints are added to the high-pressure guide pipe P+ and the low-pressure guide pipe P- of the demister, respectively, to introduce compressed air lines as the purging air source. The compressed air lines are connected in sequence to the compressed air manual ball valve 7 and the low flow switch FS, and then split into two lines connected to the positive pressure side purging solenoid valve 2 and the negative pressure side purging solenoid valve 3, respectively. The ends of the two purging lines are respectively connected to the high-pressure guide pipe P+ and the low-pressure guide pipe P- of the demister. The positive pressure side shut-off solenoid valve 4 and the negative pressure side shut-off solenoid valve 5 are connected in series in the main measurement circuit between the high-pressure guide pipe P+, ​​the low-pressure guide pipe P- of the demister, and the differential pressure measuring transmitter 6 of the demister. In the initial state, the positive pressure side pipeline purge solenoid valve 2 and the negative pressure side pipeline purge solenoid valve 3 are de-energized and closed, the positive pressure side pipeline shut-off solenoid valve 4 and the negative pressure side pipeline shut-off solenoid valve 5 are de-energized and opened, and the demister differential pressure measuring transmitter 6 normally collects the demister differential pressure signal through the demister high pressure guide pipe P+ and the demister low pressure guide pipe P-.

[0034] Furthermore, such as Figure 2 As shown, the electrical protection box contains components such as air switch QF1, fuse FU, timer KT, start-purge intermediate relay K1, and low purge flow alarm output relay K2, forming the electrical circuit of the local control box. Figure 3 As shown, the DCS logic control module integrates a high-limit monitoring algorithm unit 8, a single-pulse algorithm unit 9, a lead-lag algorithm unit 11, a subtractor algorithm unit 12, a low-limit monitoring algorithm unit 13, a logic AND algorithm unit 14, a start-purge switch input point 15, a delay-closing algorithm unit 16, a delay-opening algorithm unit 17, and a stubborn blockage alarm unit 18, to realize differential pressure signal monitoring, purging triggering, and fault diagnosis functions.

[0035] The timed purging process in this embodiment is as follows:

[0036] 1. Triggering conditions:

[0037] When the air switch QF1 in the control box is closed, the timer KT is triggered at 10:00 and 16:00 every day according to the preset program. Its normally open contact closes, energizing the coil of the intermediate purge relay K1, and activating the multiple normally open contacts of the intermediate purge relay K1 to operate synchronously.

[0038] 2. Purging execution:

[0039] When the second and third normally open contacts of the purging intermediate relay K1 are closed, the positive pressure side pipeline purging solenoid valve 2 and the negative pressure side pipeline purging solenoid valve 3 are energized and opened, and compressed air is purged through the high pressure guide pipe P+ and the low pressure guide pipe P- of the demister to remove impurities from the pipeline.

[0040] When the fourth and fifth normally open contacts of the purging intermediate relay K1 are closed, the positive pressure side pipeline shut-off solenoid valve 4 and the negative pressure side pipeline shut-off solenoid valve 5 are energized and closed, cutting off the connection between the demister high-pressure guide pipe P+, ​​the demister low-pressure guide pipe P- and the demister differential pressure measuring transmitter 6, so that the demister differential pressure measuring transmitter 6 is in the measured value holding state, avoiding damage to the components caused by the purging airflow.

[0041] 3. Traffic flow monitoring:

[0042] When the purge intermediate relay K1 is activated, its first normally open contact closes, and the low flow switch FS monitors the compressed air flow in real time. If the flow rate is lower than the set value, the low flow switch FS contacts close, the coil of the purge flow low alarm output relay K2 is energized, and the purge flow low indicator alarm unit 10 in the DCS system is triggered, indicating pipeline blockage, solenoid valve failure, or abnormal air supply.

[0043] 4. Purging complete:

[0044] After the 4-minute purging time set by timer KT is reached, its normally open contact opens, triggering the de-energization and reset of the intermediate purging relay K1.

[0045] When the positive pressure side pipeline purging solenoid valve 2 and the negative pressure side pipeline purging solenoid valve 3 are de-energized and closed, the compressed air purging stops.

[0046] When the positive pressure side pipeline shut-off solenoid valve 4 and the negative pressure side pipeline shut-off solenoid valve 5 are de-energized and open, the high pressure guide pipe P+ and the low pressure guide pipe P- of the demister are reconnected to the demister differential pressure measuring transmitter 6, and the demister differential pressure measuring transmitter 6 resumes normal differential pressure measurement.

[0047] The DCS intelligent purging process in this embodiment is as follows:

[0048] 1. Differential pressure monitoring and triggering:

[0049] The DCS logic control module collects the demister differential pressure measurement value output by the demister differential pressure measurement transmitter 6 in real time through the high limit monitoring algorithm unit 8. When the demister differential pressure measurement value exceeds the 35Pa threshold, it is determined that the pressure guide tube may be blocked, triggering the single pulse algorithm unit 9 to output a DCS start purging signal that lasts for 4 minutes. This signal energizes the coil of the start purging intermediate relay K1 through the DCS start switch DCS. The subsequent purging execution steps, solenoid valve action, flow monitoring and timed purging process are consistent.

[0050] 2. Evaluation of purging effectiveness and diagnosis of stubborn blockages:

[0051] During the output signal period of the single pulse algorithm unit 9, the lead-lag link algorithm unit 11 records the differential pressure value before purging and maintains it for 4 minutes. After purging, the subtractor algorithm unit 12 calculates the differential pressure difference before and after purging (differential pressure value before purging - differential pressure value after purging).

[0052] If the difference is less than the 10Pa threshold set by the low limit monitoring algorithm unit 13, and the delayed closing algorithm unit 16 and the delayed opening algorithm unit 17 logically determine that the purging action has been completed and the interval is 10s, the logic and algorithm unit 14 outputs a signal to the stubborn blockage alarm unit 18, indicating that there is a stubborn blockage in the pressure guide tube and manual intervention is required.

[0053] 3. Purging terminated:

[0054] After the 4-minute timing of the single-pulse algorithm unit 9 ends, the DCS start-purge signal disappears, the start-purge intermediate relay K1 is de-energized, the positive pressure side pipeline purge solenoid valve 2 and the negative pressure side pipeline purge solenoid valve 3 close, the positive pressure side pipeline shut-off solenoid valve 4 and the negative pressure side pipeline shut-off solenoid valve 5 open, and the system returns to normal measurement status.

[0055] In this embodiment, timed purging and DCS intelligent purging are logically interlocked by activating the intermediate purging relay K1: timed purging is triggered by the local timer KT to meet routine periodic maintenance needs; intelligent purging is dynamically triggered by the DCS logic control module based on real-time differential pressure data, adapting to precise purging under complex operating conditions. Both modes use the low flow switch FS and the DCS logic control module to monitor the purging process and provide fault alarms, ensuring the effectiveness and reliability of the purging operation.

[0056] The above description only describes the preferred embodiments of the present utility model. However, the present utility model is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present utility model, and all such changes should be included within the protection scope of the present utility model.

Claims

1. An intelligent purging device for differential pressure measuring pipelines of a demister, characterized in that: This includes a low flow switch (FS), a positive pressure side pipeline purge solenoid valve (2), a negative pressure side pipeline purge solenoid valve (3), a positive pressure side pipeline shut-off solenoid valve (4), a negative pressure side pipeline shut-off solenoid valve (5), a demister differential pressure measuring transmitter (6), a compressed air manual ball valve (7), a demister high-pressure guide pipe (P+), and a demister low-pressure guide pipe (P-). The demister differential pressure measuring transmitter (6) is connected to the demister high-pressure guide pipe (P+) and the demister low-pressure guide pipe (P-), respectively. The positive pressure side pipeline shut-off... The solenoid valve (4) is installed on the high pressure guide pipe (P+) of the demister, and the solenoid valve (5) of the negative pressure side pipeline is installed on the low pressure guide pipe (P-) of the demister. The high pressure guide pipe (P+) of the demister is connected to the low flow switch (FS) through the purge solenoid valve (2) of the positive pressure side pipeline. The low pressure guide pipe (P-) of the demister is connected to the low flow switch (FS) through the purge solenoid valve (3) of the negative pressure side pipeline. The low flow switch (FS) is connected to the compressed air pipeline through the compressed air manual ball valve (7).

2. The intelligent purging device for differential pressure measurement pipeline of a demister according to claim 1, characterized in that: The positive pressure side pipeline purge solenoid valve (2), negative pressure side pipeline purge solenoid valve (3), positive pressure side pipeline shut-off solenoid valve (4), and negative pressure side pipeline shut-off solenoid valve (5) are all electrically connected to the local control box electrical circuit.

3. The intelligent purging device for differential pressure measurement pipeline of a demister according to claim 2, characterized in that: The electrical circuit of the local control box includes an air switch (QF1), a fuse (FU), a timer (KT), a start-purge intermediate relay (K1), a DCS start switch (DCS), a low flow switch (FS), and a low purge flow alarm output relay (K2). The air switch (QF1) is electrically connected to the fuse (FU), the fuse (FU) is electrically connected to the coil of the timer (KT), the coil of the timer (KT) is electrically connected to the air switch (QF1), the fuse (FU) is electrically connected to the normally open contact of the timer (KT), and the normally open contact of the timer (KT) is electrically connected to the start-purge intermediate relay. The coil of the intermediate relay (K1) is electrically connected to the air switch (QF1). The DCS start switch (DCS) is connected in parallel across the normally open contact of the timer (KT). The fuse (FU) is electrically connected to the first normally open contact of the intermediate relay (K1). The first normally open contact of the intermediate relay (K1) is electrically connected to the low flow switch (FS). The low flow switch (FS) is electrically connected to the coil of the low flow alarm output relay (K2). The coil of the low flow alarm output relay (K2) is electrically connected to the air switch (QF1).

4. The intelligent purging device for differential pressure measurement pipeline of a demister according to claim 3, characterized in that: The fuse (FU) is electrically connected to the second normally open contact of the start-up purge intermediate relay (K1), and the second normally open contact of the start-up purge intermediate relay (K1) is electrically connected to the relay of the positive pressure side pipeline purge solenoid valve (2).

5. The intelligent purging device for differential pressure measurement pipeline of a demister according to claim 3, characterized in that: The fuse (FU) is electrically connected to the third normally open contact of the start-up purge intermediate relay (K1), and the third normally open contact of the start-up purge intermediate relay (K1) is electrically connected to the relay of the negative pressure side pipeline purge solenoid valve (3).

6. The intelligent purging device for differential pressure measurement pipeline of a demister according to claim 3, characterized in that: The fuse (FU) is electrically connected to the fourth normally open contact of the start-purge intermediate relay (K1), and the fourth normally open contact of the start-purge intermediate relay (K1) is electrically connected to the relay of the positive pressure side pipeline shut-off solenoid valve (4).

7. The intelligent purging device for differential pressure measurement pipeline of a demister according to claim 3, characterized in that: The fuse (FU) is electrically connected to the fifth normally open contact of the start-purge intermediate relay (K1), and the fifth normally open contact of the start-purge intermediate relay (K1) is electrically connected to the relay of the negative pressure side pipeline shut-off solenoid valve (5).

8. The intelligent purging device for differential pressure measurement pipeline of a demister according to claim 3, characterized in that: The DCS start switch (DCS) is electrically connected to the DCS logic control module.

9. The intelligent purging device for differential pressure measuring pipeline of a demister according to claim 8, characterized in that: The DCS logic control module includes a high limit monitoring algorithm unit (8), a single pulse algorithm unit (9), and a low purge flow light alarm unit (10). The input terminal of the high limit monitoring algorithm unit (8) is connected between the high pressure guide tube (P+) and the low pressure guide tube (P-) of the demister. The threshold of the high limit monitoring algorithm unit (8) is set to 35Pa. When the input differential pressure measurement value exceeds the threshold, its output terminal triggers the single pulse algorithm unit (9). The single pulse algorithm unit (9) is set to 4min. Its output terminal is connected to the DCS start switch (DCS) to output a start purge signal that lasts for 4min. The coil of the low purge flow alarm output relay (K2) is connected to the low purge flow light alarm unit (10).

10. The intelligent purging device for differential pressure measurement pipeline of a demister according to claim 9, characterized in that: The DCS logic control module also includes a lead-lag algorithm unit (11), a subtractor algorithm unit (12), a low-limit monitoring algorithm unit (13), a logic AND algorithm unit (14), a start-purge switch input point (15), a delay-closing algorithm unit (16), a delay-opening algorithm unit (17), and a stubborn blockage alarm unit (18). The input terminal of the lead-lag algorithm unit (11) is connected between the high-pressure guide pipe (P+) and the low-pressure guide pipe (P-) of the demister. The threshold of the lead-lag algorithm unit (11) is set to 4 minutes. The output terminal of the lead-lag algorithm unit (11) is connected to the input terminal of the subtractor algorithm unit (12) to calculate the differential pressure difference before and after purging. The output terminal of the subtractor algorithm unit (12) is connected to the low-limit monitoring algorithm unit (12). The input terminal of the monitoring algorithm unit (13) is connected to the input terminal of the logic AND algorithm unit (14). The threshold of the low limit monitoring algorithm unit (13) is set to 10 Pa. The output terminal of the low limit monitoring algorithm unit (13) is connected to the input terminal of the logic AND algorithm unit (14). The input terminal of the start purge switch input point (15) is connected to the input terminal of the delay closing algorithm unit (16). The threshold of the delay closing algorithm unit (16) is set to 4 min. The output terminal of the delay closing algorithm unit (16) is connected to the input terminal of the delay opening algorithm unit (17). The threshold of the delay opening algorithm unit (17) is set to 10 s. The output terminal of the delay opening algorithm unit (17) is connected to the input terminal of the logic AND algorithm unit (14). The output terminal of the logic AND algorithm unit (14) is connected to the stubborn blockage alarm unit (18).

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