Intelligent purging device for demister differential pressure measurement pipeline

Abstract

The invention belongs to the technical field of wet flue gas desulfurization, and particularly relates to an intelligent purging device for a demister differential pressure measurement pipeline, a demister differential pressure measurement transmitter is respectively communicated with a demister high pressure guide pipe and a demister low pressure guide pipe, a positive pressure side pipeline shutoff solenoid valve is arranged on the demister high pressure guide pipe, and a negative pressure side pipeline shutoff solenoid valve is arranged on the demister low pressure guide pipe. The negative pressure side pipeline shutoff solenoid valve is arranged on the demister low pressure guide pipe, the demister high pressure guide pipe is connected with the flow low switch through the positive pressure side pipeline purging solenoid valve, and the demister low pressure guide pipe is connected with the flow low switch through the negative pressure side pipeline purging solenoid valve. And the low-flow switch is connected with a compressed air pipeline through a compressed air manual ball valve. According to the intelligent purging device for the demister differential pressure measurement pipeline, through innovative design of a hardware structure and intelligent control logic, the problems that a traditional purging device is low in automation degree, extensive in purging strategy, insufficient in fault diagnosis capacity and the like are effectively solved.

Description

Technical Field

[0001] The invention belongs to the technical field of wet flue gas desulfurization, and particularly relates to an intelligent purging device for a demister differential pressure measuring pipeline. Background Art

[0002] In industrial production, especially in limestone-gypsum wet flue gas desulfurization systems, demisters are crucial equipment, removing mist droplets from the flue gas to ensure the safe operation of subsequent equipment. Measuring demister differential pressure is a key step in monitoring its operating status. Accurate differential pressure data can reflect demister blockage and operating efficiency, providing a basis for stable system regulation.

[0003] However, during actual operation, the demister's high-pressure and low-pressure pressure pipes are susceptible to contamination from impurities such as gypsum slurry and dust in the flue gas, leading to pipe blockage and, in turn, inaccurate or even ineffective differential pressure measurement. Once the pressure pipes become clogged, not only does it affect the real-time monitoring of the demister's operating status, it can also cause misjudgments in the control system, posing a threat to the safe and stable operation of the entire desulfurization system.

[0004] Existing differential pressure measurement pipeline purging technology has significant shortcomings. Traditional manual purging requires operators to frequently check the pipeline status and manually activate the purging device. This is labor-intensive and unresponsive, making it difficult to remove impurities in the initial accumulation stage, which can easily lead to the gradual exacerbation of blockage problems. While some automated purging devices implement timed purging, they lack real-time monitoring and intelligent judgment of differential pressure data, which can lead to over-purging or under-purging. Over-purging wastes compressed air resources and increases energy consumption, while under-purging fails to effectively remove impurities in the pipeline, resulting in persistent measurement errors.

[0005] Furthermore, existing technologies for purge flow monitoring and anomaly alarms are limited. When compressed air flow is insufficient or a stubborn blockage occurs in the pipeline, timely alarms and appropriate action are not issued, further impacting the reliability of the differential pressure measurement system. Furthermore, traditional devices suffer from deficiencies in electrical control and logic algorithms, making it impossible to accurately control the purge process based on the dynamic trends of differential pressure changes. Furthermore, it is difficult to evaluate and provide feedback on the purge effect, resulting in a low level of intelligence for the entire purge system. Summary of the Invention

[0006] In response to the above-mentioned technical problems existing in the purge of the differential pressure measuring pipeline of the existing demister, the present invention provides an intelligent purge device for the differential pressure measuring pipeline of the demister.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is: A defogger differential pressure measuring pipeline intelligent purging device, comprising a low flow switch, a positive pressure side pipeline purge solenoid valve, a negative pressure side pipeline purge solenoid valve, a positive pressure side pipeline shut-off solenoid valve, a negative pressure side pipeline shut-off solenoid valve, a defogger differential pressure measuring transmitter, a compressed air manual ball valve, a defogger high-pressure pressure pipe and a defogger low-pressure pressure pipe, the defogger differential pressure measuring transmitter being connected to the defogger high-pressure pressure pipe and the defogger low-pressure pressure pipe respectively, the positive pressure side pipeline shut-off solenoid valve being arranged on the defogger high-pressure pressure pipe, the negative pressure side pipeline shut-off solenoid valve being arranged on the defogger low-pressure pressure pipe, the defogger high-pressure pressure pipe being connected to the low flow switch through the positive pressure side pipeline purge solenoid valve, the defogger low-pressure pressure pipe being connected to the low flow switch through the negative pressure side pipeline purge solenoid valve, and the low flow switch being connected to the compressed air pipeline through the compressed air manual ball valve.

[0008] The positive-pressure side pipeline purge solenoid valve, the negative-pressure side pipeline purge solenoid valve, the positive-pressure side pipeline shut-off solenoid valve and the negative-pressure side pipeline shut-off solenoid valve are all electrically connected to the electrical circuit of the local control box.

[0009] The electrical circuit of the on-site control box 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 coil of the timer 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 coil of the start-purge intermediate relay is electrically connected to the air switch, the DCS start switch is connected in parallel at both ends of the normally open contacts 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 coil of the low purge flow alarm output relay is electrically connected to the air switch.

[0010] 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.

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

[0012] The fuse is electrically connected to the fourth normally open contact of the start-up purge intermediate relay, and the fourth normally open contact of the start-up purge intermediate relay is electrically connected to the relay of the positive pressure side pipeline shut-off solenoid valve.

[0013] The fuse is electrically connected to the fifth normally open contact of the start-up purge intermediate relay, and the fifth normally open contact of the start-up purge intermediate relay is electrically connected to the relay of the negative pressure side pipeline shut-off solenoid valve.

[0014] The DCS start switch is electrically connected to a DCS logic control module.

[0015] The DCS logic control module includes a high-limit monitoring algorithm unit, a single-pulse algorithm unit, and a low-purge flow light-sign alarm unit. The input end of the high-limit monitoring algorithm unit is connected between the defogger high-pressure pressure pipe and the defogger low-pressure pressure pipe. The threshold of the high-limit monitoring algorithm unit is set to 35Pa. When the input differential pressure measurement value exceeds the threshold, its output end triggers the single-pulse algorithm unit; the setting value of the single-pulse algorithm unit is 4min, and its output end is connected to the DCS start switch to output a start-up purge signal lasting 4min; the coil of the low-purge flow alarm output relay is connected to the low-purge flow light-sign alarm unit.

[0016] The DCS logic control module also includes an advance-lag link algorithm unit, a subtractor algorithm unit, a low-limit monitoring algorithm unit, a logic and algorithm unit, a start-purge switch input point, a delayed closing algorithm unit, a delayed opening algorithm unit and a stubborn blockage alarm unit. The input end of the advance-lag link algorithm unit is connected between the defogger high-pressure pressure pipe and the defogger low-pressure pressure pipe. The threshold of the advance-lag link algorithm unit is set to 4 minutes. The output end of the advance-lag link algorithm unit is connected to the input end of the subtractor algorithm unit for calculating the differential pressure difference before and after purge; the output end of the subtractor algorithm unit is connected to the low-limit monitoring The input end of the algorithm unit, the threshold value of the lower limit monitoring algorithm unit is set to 10Pa, and the output end of the lower limit monitoring algorithm unit is connected to the input end of the logic and algorithm unit; the input end of the start purge switch input point is connected to the input end of the delayed closing algorithm unit, and the threshold value of the delayed closing algorithm unit is set to 4min. The output end of the delayed closing algorithm unit is connected to the input end of the delayed disconnection algorithm unit, and the threshold value of the delayed disconnection algorithm unit is set to 10s; the output end of the delayed disconnection algorithm unit is connected to the input end of the logic and algorithm unit, and the output end of the logic and algorithm unit is connected to the stubborn blockage alarm unit.

[0017] Compared with the prior art, the present invention has the following beneficial effects: 1. The intelligent purging device for the demister differential pressure measurement pipeline provided by the present invention effectively solves the problems of low automation, extensive purging strategy, and insufficient fault diagnosis capability existing in traditional purging devices through the innovative design of hardware structure and intelligent control logic. The device monitors the differential pressure value of the high and low pressure 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 the purge according to the actual blockage degree of the pipeline avoids the blindness of traditional timed purging, prevents the waste of compressed air caused by excessive purging, and eliminates measurement failures caused by severe blockage and failure to purge in time, so that the purging operation is accurately matched with the pipeline pollution status, significantly improving the real-time performance and reliability of the differential pressure measurement system. 2. The low flow switch and the low purge flow alarm output relay of the present invention form a monitoring circuit, which detects the compressed air purge flow in real time. When the flow is insufficient, an alarm is immediately issued through the light-emitting alarm unit to avoid ineffective purge due to insufficient air source pressure or pipeline leakage; at the same time, the differential pressure difference before and after purge is calculated through the lead-lag link algorithm unit and the subtractor algorithm unit, and combined with the delayed closing / opening algorithm logic, it can be determined whether there is stubborn blockage in the pipeline and trigger an alarm, providing a clear fault location signal for manual intervention, and solving the defect that the traditional device has no feedback on the purge effect. 3. The present invention integrates two modes: the local control box electrical circuit and the DCS remote control. The local control realizes periodic automatic purge through a timer to meet the needs of conventional operation scenarios; the DCS remote control supports the host computer to flexibly intervene in the purge strategy according to the system operation status. Both modes control the positive and negative pressure side purge solenoid valves and the shut-off solenoid valve respectively by starting multiple groups of normally open contacts of the purge intermediate relay, ensuring that the pressure pipe and the differential pressure transmitter are reliably isolated during purge, avoiding damage to the measuring element by the impact of compressed air, and improving the safety of the device operation and the control flexibility. 4. The intelligent logic algorithm of the present invention accurately controls the timing and duration of purges, which can significantly reduce compressed air consumption and lower energy costs compared to traditional timed purges. The multiple algorithm units of the DCS logic control module construct a fully closed-loop intelligent control system, which can achieve self-maintenance of the differential pressure measurement pipeline without frequent manual inspections, and improve the automation level of the purge device from mechanical timing to data-driven decision-making, completing an intelligent upgrade. 5. The modular design of the positive and negative pressure side pipeline shut-off solenoid valve and the purge solenoid valve of the present invention completely isolates the pressure pipe from the measurement circuit during purging, avoiding the backflow of impurities and contamination of the transmitter during the purge 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 purge functions when some components fail. The overall structure is simple and the functional redundancy is high, which reduces maintenance complexity and extends the average trouble-free operation time of the differential pressure measurement system. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the embodiments or the description of the prior art. Obviously, the drawings described below are merely exemplary, and those skilled in the art can, without inventive effort, derive other implementation drawings based on the provided drawings.

[0019] The structures, proportions, sizes, etc. illustrated in this specification are intended solely to complement the contents disclosed herein and to facilitate understanding and reading by persons skilled in the art. They are not intended to limit the conditions under which the present invention may be implemented and therefore have no substantive technical significance. Any structural modifications, changes in proportions, or adjustments in sizes, without affecting the efficacy and objectives of the present invention, shall remain within the scope of the technical contents disclosed herein.

[0020] Figure 1 It is a schematic diagram of the on-site gas path of the present invention; Figure 2 This is the electrical circuit diagram of the local control box of the present invention; Figure 3 This is a schematic diagram of the DCS logic control module of the present invention.

[0021] Among them: 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 defogger differential pressure measurement transmitter, 7 is the compressed air manual ball valve, P+ is the defogger high pressure pipe, P- is the defogger low pressure pipe, QF1 is the air switch, FU is the fuse, KT is the timer, K1 is the start purge intermediate relay, DCS is the DCS Start switch, K2 is the purge flow low alarm output relay, 8 is the high limit monitoring algorithm unit, 9 is the single pulse algorithm unit, 10 is the purge flow low light sign 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 delayed closing algorithm unit, 17 is the delayed disconnection algorithm unit, and 18 is the stubborn blockage alarm unit. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of this application, not all the embodiments. These descriptions are only to further illustrate the features and advantages of the present invention, rather than to limit the claims of the present invention. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0023] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following embodiments are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0024] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0025] This embodiment provides a demister differential pressure measurement pipeline intelligent purge device, such as Figure 1 As shown, a tee joint is added to the demister's high-pressure and low-pressure piping, P+, respectively, to introduce a compressed air pipeline as the purge air source. The compressed air pipeline is connected in sequence to a compressed air manual ball valve 7 and a low-flow switch FS. It is then split into two routes, connected to the positive-pressure piping purge solenoid valve 2 and the negative-pressure piping purge solenoid valve 3. The ends of the two purge pipelines are respectively connected to the demister's high-pressure and low-pressure piping, P+, and P-. The positive-pressure shutoff solenoid valve 4 and the negative-pressure shutoff solenoid valve 5 are connected in series to the main measurement circuit between the demister's high-pressure and low-pressure piping, P+, and P-, respectively, and the demister's differential pressure transmitter 6. In the initial state, the positive pressure side pipeline purge solenoid valve 2 and the negative pressure side pipeline purge solenoid valve 3 are powered off and closed, the positive pressure side pipeline shut-off solenoid valve 4 and the negative pressure side pipeline shut-off solenoid valve 5 are powered off and open, and the demister differential pressure measurement transmitter 6 collects the demister differential pressure signal normally through the demister high-pressure pressure pipe P+ and the demister low-pressure pressure pipe P-.

[0026] Further, if Figure 2 As shown, the electrical protection box is equipped with air switch QF1, fuse FU, timer KT, start purge intermediate relay K1, purge flow low alarm output relay K2 and other components to form the local control box electrical circuit. Figure 3As shown, the DCS logic control module integrates a high-limit monitoring algorithm unit 8, a single-pulse algorithm unit 9, a lead-lag link 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 time-delay closing algorithm unit 16, a time-delay opening algorithm unit 17, and a stubborn blockage alarm unit 18, to realize differential pressure signal monitoring, purge triggering, and fault diagnosis functions.

[0027] The timing purge process of this embodiment is as follows: 1. Trigger conditions: When the air switch QF1 of 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 contacts are closed, the coil of the start-purge intermediate relay K1 is energized, and the multiple groups of normally open contacts of the start-purge intermediate relay K1 act synchronously. 2. Purge execution: The second and third normally open contacts of the start-up purge intermediate relay K1 are closed, the positive pressure side pipeline purge solenoid valve 2 and the negative pressure side pipeline purge solenoid valve 3 are energized to open, and the compressed air purges pipeline impurities through the defogger high-pressure pressure pipe P+ and the defogger low-pressure pressure pipe P-. The fourth and fifth normally open contacts of the start-up purge 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 defogger high-pressure pressure pipe P+, the defogger low-pressure pressure pipe P- and the defogger differential pressure measuring transmitter 6, so that the defogger differential pressure measuring transmitter 6 is in the measurement value holding state to avoid damage to the components due to the impact of the purge airflow. 3. Flow monitoring: When the purge 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 falls below the set value, the low flow switch FS contacts close, energizing the coil of the low purge flow alarm output relay K2, triggering the low purge flow light-up sign alarm unit 10 in the DCS system, indicating a pipeline blockage, solenoid valve failure, or air source abnormality. 4. End of purge: When the 4-minute purge time set by timer KT is reached, its normally open contact is disconnected, and the start-purge intermediate relay K1 loses power and resets: The positive pressure side pipeline purge solenoid valve 2 and the negative pressure side pipeline purge solenoid valve 3 lose power and close, and the compressed air stops purging; The positive pressure side pipeline shut-off solenoid valve 4 and the negative pressure side pipeline shut-off solenoid valve 5 are opened after power is lost, and the demister high-pressure pressure pipe P+, the demister low-pressure pressure pipe P- and the demister differential pressure measurement transmitter 6 are restored to connection, and the demister differential pressure measurement transmitter 6 resumes normal differential pressure measurement.

[0028] The DCS intelligent purge process of this embodiment is as follows: 1. Differential pressure monitoring and triggering: 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 threshold value of 35Pa, it determines that the pressure pipe may be blocked, triggering the single-pulse algorithm unit 9 to output a DCS start purge signal lasting 4 minutes. This signal energizes the coil of the start purge intermediate relay K1 through the DCS start switch DCS. The subsequent purge execution steps, solenoid valve action, flow monitoring and timed purge process are consistent. 2. Evaluation of purge effect and diagnosis of stubborn blockage: During the period when the single pulse algorithm unit 9 outputs the signal, the lead-lag link algorithm unit 11 records the differential pressure value before purge and keeps it for 4 minutes. After the purge is completed, the subtractor algorithm unit 12 calculates the differential pressure difference before and after purge (differential pressure value before purge - differential pressure value after purge). If the difference is less than the 10Pa threshold set by the lower limit monitoring algorithm unit 13, and the delayed closing algorithm unit 16 and the delayed opening algorithm unit 17 logically determine that the purge 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 stubborn blockage in the pressure pipe and manual intervention is required. 3. Purge termination: After the 4-minute timing of the single-pulse algorithm unit 9 ends, the DCS start-up purge signal disappears, the start-up purge intermediate relay K1 loses power, the positive-pressure side pipeline purge solenoid valve 2 and the negative-pressure side pipeline purge solenoid valve 3 are closed, the positive-pressure side pipeline shut-off solenoid valve 4 and the negative-pressure side pipeline shut-off solenoid valve 5 are opened, and the system returns to normal measurement status.

[0029] In this embodiment, the timed purge and DCS intelligent purge functions are logically interlocked by activating the purge relay K1. Timed purge is triggered by the local timer KT, meeting routine periodic maintenance requirements; intelligent purge is dynamically triggered by the DCS logic control module based on real-time differential pressure data, enabling precise purge operation under complex operating conditions. Both modes utilize the low-flow switch FS and the DCS logic control module for purge process monitoring and fault alarms, ensuring the effectiveness and reliability of the purge operation.

[0030] The above only describes in detail the preferred embodiments of the present invention, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in this field without departing from the purpose of the present invention, and various changes should be included in the scope of protection of the present invention.

Claims

1. An intelligent purge device for a demister differential pressure measurement pipeline, characterized by: The invention comprises 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 guiding pipe (P+) and a demister low pressure guiding pipe (P-), wherein the demister differential pressure measuring transmitter (6) is connected to the demister high pressure guiding pipe (P+) and the demister low pressure guiding pipe (P-) respectively, and the positive pressure side pipeline shut-off solenoid valve (4) is connected to the positive pressure side pipeline shut-off solenoid valve (5). The shut-off solenoid valve (4) is arranged on the high-pressure pressure pipe (P+) of the demister, and the negative-pressure side pipeline shut-off solenoid valve (5) is arranged on the low-pressure pressure pipe (P-) of the demister. The high-pressure pressure pipe (P+) of the demister is connected to the low-flow switch (FS) through the positive-pressure side pipeline purge solenoid valve (2), and the low-pressure pressure pipe (P-) of the demister is connected to the low-flow switch (FS) through the negative-pressure side pipeline purge solenoid valve (3). 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 the demister differential pressure measurement pipeline according to claim 1, characterized in that: The positive-pressure side pipeline purge solenoid valve (2), the negative-pressure side pipeline purge solenoid valve (3), the positive-pressure side pipeline shutoff solenoid valve (4), and the negative-pressure side pipeline shutoff solenoid valve (5) are all electrically connected to the electrical circuit of the local control box.

3. The intelligent purging device for the demister differential pressure measurement pipeline 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-up 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), which 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-up purge intermediate relay (K1). The coil of the start-purge intermediate relay (K1) is electrically connected to the air switch (QF1), the DCS start switch (DCS) is connected in parallel to the two ends of the normally open contacts of the timer (KT), the fuse (FU) is electrically connected to the first normally open contact of the start-purge intermediate relay (K1), the first normally open contact of the start-purge 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 purge flow alarm output relay (K2), and the coil of the low purge flow alarm output relay (K2) is electrically connected to the air switch (QF1).

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

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

9. The intelligent purging device for the demister differential pressure measurement pipeline 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-sign alarm unit (10). The input end of the high-limit monitoring algorithm unit (8) is connected between the demister high-pressure pressure pipe (P+) and the demister low-pressure pressure pipe (P-). The threshold of the high-limit monitoring algorithm unit (8) is set to 35 Pa. When the input differential pressure measurement value exceeds the threshold, its output end triggers the single-pulse algorithm unit (9); the setting value of the single-pulse algorithm unit (9) is 4 minutes, and its output end is connected to the DCS start switch (DCS) for outputting a start purge signal lasting 4 minutes; the coil of the low-purge flow alarm output relay (K2) is connected to the low-purge flow light-sign alarm unit (10).

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

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