Water electrolysis hydrogen production pipeline CMP pretreatment drying device

Abstract

The invention provides a water electrolysis hydrogen production pipeline CMP pretreatment drying device, and belongs to the field of chemical equipment. According to the technical scheme, the device comprises a drying device and a supporting conveying frame arranged on one side of the drying device, and the drying device comprises a vacuum negative pressure system, a high-frequency pulse hot air system, an intelligent control unit, a pipeline connecting structure and a pipeline plug. The pipeline drying device has the beneficial effects that the pipeline is dried through vacuum negative pressure and high-frequency pulse hot air synergistic drying, the pipeline drying efficiency is greatly improved, water residues are reduced, and the long-term stability of a hydrogen energy system is ensured.

Description

Technical Field

[0001] The present invention relates to the field of chemical equipment, and particularly to a CMP pretreatment drying device for electrolytic water hydrogen production pipelines. Background Art

[0002] With the rapid development of hydrogen energy technology, stainless steel pipelines are increasingly widely used in hydrogen production, storage, and transportation systems. However, due to the extremely high permeability of hydrogen, materials are prone to hydrogen embrittlement problems after long-term exposure to a hydrogen environment, resulting in a decrease in mechanical strength, crack propagation, and even pipeline failure. Therefore, in order to ensure the long-term stable operation of hydrogen energy pipelines, strict surface treatment must be carried out on the pipelines before installation to optimize the material structure, improve the hydrogen embrittlement resistance, and reduce the risk of hydrogen leakage;

[0003] Among many stainless steel surface treatment methods, chemical mechanical polishing has become the core technology for hydrogen energy pipeline pretreatment because it can provide high-precision surface flatness, eliminate micro-defects, and reduce the residual stress on the pipeline surface. Through the synergistic effect of chemical etching and mechanical grinding, CMP can effectively remove the processing damage layer, metal oxide layer, and pollutants on the inner wall of the pipeline, thereby improving the smoothness, corrosion resistance, and hydrogen embrittlement resistance of the pipeline;

[0004] However, in practical applications, pipelines after CMP treatment often have a certain amount of chemical residues and moisture remaining. If not removed promptly and thoroughly, it may affect subsequent airtightness detection, pipeline installation, and long-term operation stability. To solve this problem, the industry generally uses drying technology to remove the moisture after CMP pretreatment. Traditional natural air drying or low-temperature heating drying methods often have low efficiency and are difficult to ensure the complete removal of moisture in the complex internal structures of the pipeline (such as welds, elbows, and micropores). Summary of the Invention

[0005] The purpose of the present invention is to provide a CMP pretreatment drying device for electrolytic water hydrogen production pipelines that uses the synergistic drying of vacuum negative pressure and high-frequency pulsed hot air to dry the pipeline, greatly improving the drying efficiency of the pipeline, reducing moisture residue, and ensuring the long-term stability of the hydrogen energy system.

[0006] The present invention is achieved by the following measures:

[0007] A CMP pretreatment drying device for electrolytic water hydrogen production pipelines, characterized in that it includes a drying device and a support conveyor frame arranged on one side of the drying device;

[0008] The drying device includes a vacuum negative pressure system, a high-frequency pulsed hot air system, an intelligent control unit, and a pipeline connection structure;

[0009] The drying process includes the following steps:

[0010] S1. Pipeline connection and plugging: Place the hydrogen production pipeline on the support and conveying rack and convey it to the position of the drying device. Then, connect one end of the hydrogen production pipeline to the pipeline connection structure of the drying device and seal the other end with a pipeline plug head.

[0011] S2. Pipeline airtightness detection: Start the vacuum negative pressure system for airtightness detection.

[0012] S3. Vacuum negative pressure drying: Start the vacuum negative pressure system to extract the moisture inside the pipeline.

[0013] S4. High-frequency pulse hot air drying: Start the high-frequency pulse hot air system to dry the inside of the hydrogen production pipeline.

[0014] S5. Cooling and restoring normal pressure: Gradually reduce the negative pressure to restore the normal atmospheric pressure inside the pipeline and introduce low-temperature air for cooling.

[0015] The specific features of the present invention further include:

[0016] The vacuum negative pressure system includes a vacuum pump, a water vapor separator, and a negative pressure regulating valve;

[0017] The vacuum pump is connected to the water vapor separator through a pipeline. The air outlet end of the water vapor separator is connected to the negative pressure regulating valve, and the output end of the negative pressure regulating valve is connected to the pipeline connection structure through a pipeline.

[0018] The high-frequency pulse hot air system includes a high-temperature pulse blower, a pulse controller, and a wind pressure regulating valve;

[0019] The air outlet end of the high-temperature pulse blower is connected to the pulse controller. The pulse controller controls the air flow intensity through the wind pressure regulating valve, and the output end of the wind pressure regulating valve is connected to the pipeline connection structure through a pipeline.

[0020] The pipeline connection structure includes a communication chamber. One side of the communication chamber is connected to the output ends of the negative pressure regulating valve and the wind pressure regulating valve. The other side of the communication chamber is provided with a connecting pipe. The outer periphery of the end of the connecting pipe is provided with a front annular sealing plate, and a plurality of gas distribution plates are arranged in parallel in the communication chamber.

[0021] An air inlet pipe is arranged on the side wall of the communication chamber, and the air inlet pipe is connected to a cooling fan.

[0022] An exhaust pipe is arranged on the pipeline plug head, and an electromagnetic valve is arranged on the exhaust pipe;

[0023] Preferably, the pipeline plug head includes a sealing plate. A limiting stud is arranged on the side surface of the sealing plate. A sealing gasket is arranged on the sealing plate around the limiting stud, and the size of the limiting stud is smaller than the size of the pipeline;

[0024] During plugging, insert the limit head into the pipeline, and the plugging plate abuts against the end of the pipeline to form a plug. Side plates are arranged on both sides of the plugging plate, and the side plates are arranged on the frame of the support conveyor through bolts. A long installation groove is formed on the frame of the support conveyor, and an installation nut is arranged at the end of the bolt passing through the long installation groove.

[0025] The intelligent control unit includes: a humidity monitoring module, a temperature monitoring module, a pressure monitoring module, a wind speed monitoring module, and a low-temperature air flow monitoring module.

[0026] The humidity monitoring module is expressed as:

[0027]

[0028] Where:

[0029] H is the relative humidity inside the pipeline;

[0030] P sat is the saturated water vapor pressure at the current temperature;

[0031] P v is the partial pressure of water vapor inside the pipeline;

[0032] α1 is the contribution coefficient of negative pressure evaporation to the humidity decrease;

[0033] α2 is the contribution coefficient of wind speed disturbance to the humidity decrease;

[0034] α3 is the contribution coefficient of hot air heating to the humidity decrease.

[0035] Control target:

[0036] H final ≤5%;

[0037] That is, reduce the humidity to below 5% to ensure complete dryness;

[0038] The temperature monitoring module is expressed as:

[0039]

[0040] Where:

[0041] T pipe (t) is the internal temperature of the pipeline;

[0042] T init is the initial temperature;

[0043] Q air is the heat transferred to the pipeline;

[0044] m pipe is the mass of the pipeline;

[0045] C p is the specific heat capacity of the pipeline material;

[0046] λ c is the heat loss coefficient.

[0047] Control objective:

[0048] T pipe ∈[80 °C, 120 °C];

[0049] That is, ensure that the internal temperature of the pipeline is between 80 - 120 °C and optimize the water evaporation rate;

[0050] The pressure monitoring module is expressed as:

[0051] 0.06 ≤ P v (t) ≤ 0.09 Mpa

[0052]

[0053] Where:

[0054] P v (t) is the partial pressure of water vapor inside the pipeline;

[0055] P v0 is the initial partial pressure of water vapor;

[0056] is the pumping rate of the vacuum pump;

[0057] H target is the target humidity;

[0058] Control objective:

[0059] 0.06 ≤ P v (t) ≤ 0.09 Mpa;

[0060] That is, keep the internal negative pressure of the pipeline between 0.06 - 0.09 Mpa to ensure effective dehumidification without damaging the pipeline;

[0061] The wind speed monitoring module is expressed as:

[0062]

[0063] Where:

[0064] V air is the wind speed inside the pipeline;

[0065] e H = H - H target is the humidity error;

[0066] K p,K i ,K d is the PID control parameter;

[0067] γ1, γ2 are disturbance optimization coefficients;

[0068] Control objectives:

[0069] 5≤Vair(t)≤20m / s;

[0070] That is, ensure moderate wind speed to avoid local overheating or overcooling and improve drying uniformity;

[0071] The low temperature air flow monitoring module is represented as:

[0072]

[0073] in:

[0074] Q cool (t) is the flow rate of cooling air;

[0075] λ1, λ2 are cooling rate parameters;

[0076] V cool is the wind speed of cooling air;

[0077] Control objectives:

[0078] Q cool (t)≥Q min ;

[0079] That is, ensure that the cooling air volume is sufficient to prevent the pipe temperature from dropping too quickly or too slowly.

[0080] The drying process includes the following steps:

[0081] S1. Pipeline connection and plugging: dock one end of the hydrogen production pipeline with the connecting pipe of the drying device (using the front annular plugging plate to form a plug), and seal the other end with a pipeline plug. The pipeline plug and the front annular plugging plate form a plug on the hydrogen production pipeline, and all vent valves are closed at the same time;

[0082] S2. Pipeline tightness test: Start the vacuum negative pressure system to perform a tightness test. Start the vacuum pump and gradually extract the air inside the pipeline to create a negative pressure environment. Turn off the vacuum pump (keep the pipeline closed) and observe whether the pressure inside the pipeline changes over time.

[0083] The pipeline tightness test includes the following steps:

[0084] (1) Evacuate and create negative pressure:

[0085] Start the vacuum pump and gradually extract the air inside the pipeline to create a negative pressure environment of 0.06 - 0.09 MPa;

[0086] Pressure stability calculation:

[0087] P init = P atm - ΔP;

[0088] Where:

[0089] P init is the initial pressure after the establishment of the negative pressure system;

[0090] P atm is the ambient atmospheric pressure;

[0091] ΔP is the target negative pressure value (0.06 - 0.09 MPa);

[0092] (2) Close the vacuum pump and monitor the pressure change

[0093] Close the vacuum pump (keep the pipeline closed) and observe whether the pressure inside the pipeline changes with time;

[0094] Measure the pressure change rate inside the pipeline:

[0095]

[0096] Where:

[0097] L is the leakage rate (unit: Pa / s);

[0098] P is the pressure inside the pipeline;

[0099] t is the time;

[0100] dP / dt: represents the differential of pressure P with respect to time t, that is, the rate of pressure change per unit time;

[0101] Hermeticity judgment criterion:

[0102] L ≤ L max ;

[0103] L max is the acceptable leakage rate (such as 0.5 Pa / s);

[0104] (3) Evaluate the hermeticity

[0105] If L ≤ Lmax, it means that the pipeline has good hermeticity, the test passes, and proceed to step S3;

[0106] If L > Lmax, it means that there is a leak in the pipeline, and it is necessary to further check the sealing components and repair them;

[0107] S3. Pipeline drying treatment is carried out by combining vacuum negative pressure drying and high-frequency pulsed hot air drying. Start the vacuum negative pressure system to extract the moisture inside the pipeline, and start the high-frequency pulsed hot air system to dry the inside of the hydrogen production pipeline;

[0108] It includes three treatment periods:

[0109] Initial stage (the vacuum negative pressure system starts first, the high-frequency pulsed hot air drying has not started yet, and the pipeline plug remains closed)

[0110] The vacuum negative pressure system is started to form a negative pressure of 0.06 - 0.09 MPa, causing the moisture inside the pipeline to start evaporating. The water vapor separator operates to discharge the moisture extracted by the negative pressure, ensuring that the water vapor does not accumulate in the vacuum pump;

[0111] When the humidity drops below 70%, it enters the next stage;

[0112] At this time, the high-frequency pulsed hot air system has not been started yet, mainly relying on the low-temperature evaporation effect of the negative pressure to reduce the initial moisture content;

[0113] Middle stage (the vacuum negative pressure system continues to operate, the high-frequency pulsed hot air drying is gradually started, and the solenoid valve at the end of the exhaust pipe of the pipeline plug is controlled to open, allowing a small amount of air to pass through to optimize the air flow disturbance)

[0114] The high-temperature pulse fan is started to provide high-temperature pulsed hot air at 80 - 120 °C, increasing the temperature inside the pipeline and accelerating the evaporation rate of the remaining moisture; [[ID=2,3]]

[0115] The air flow distribution plate enables the hot air to be evenly distributed throughout the pipeline;

[0116] The vacuum negative pressure system continues to operate, but the air extraction rate gradually decreases to ensure that the hot air can fully act inside the pipeline without being drawn away too quickly. At the same time, the solenoid valve air vent of the pipeline plug is slightly opened (20% opening) to ensure that part of the moisture is discharged with the hot air. The vacuum pump continues to operate (the air extraction rate is reduced to 30%). The hot air system continues to heat at a temperature of 80 - 120 °C, and the humidity drops to ≤10%, entering the later stage;

[0117] During this period, the intelligent control unit dynamically adjusts the wind speed and negative pressure intensity to ensure the combined action of the hot air and negative pressure, improve the drying efficiency, and the vacuum negative pressure drying (vacuum negative pressure system) and high-frequency pulsed hot air drying (high-frequency pulsed hot air drying) are partially overlapped to improve the drying uniformity and ensure the complete evaporation of the residual moisture;

[0118] Later stage (the vacuum negative pressure system stops, and the high-frequency pulsed hot air drying independently completes the drying, and the air vent of the pipeline plug is further opened)

[0119] Gradually shut down the vacuum negative pressure system to avoid excessive extraction affecting the residence time of the hot air. The pulse hot air continues to act to ensure that the surface and interior of the pipe fully meet the set drying standards.

[0120] The vent of the pipe plug is further opened (35% opening) to control the rate of hot air discharge and ensure that the water vapor is completely discharged.

[0121] When the intelligent monitoring system detects that the humidity reaches the drying target value, the high-frequency pulse hot air system gradually reduces the fan power and prepares to enter the cooling stage;

[0122] During this period, vacuum negative pressure drying (vacuum negative pressure system) is completely stopped, and high-frequency pulse hot air drying independently completes the final drying work to ensure that the final moisture is completely removed;

[0123] Finally, step S5 is entered to cool down and restore normal pressure;

[0124] S5. Cooling and restoring normal pressure: gradually reduce the negative pressure to restore the normal atmospheric pressure inside the pipeline, and introduce low-temperature air for cooling;

[0125] The main goal of the S5 (cooling and restoring normal pressure) stage is to stabilize and restore the internal pressure of the pipeline and accurately control the cooling rate to prevent thermal stress, microcracks or local deformation of the material caused by sudden temperature drops, thereby ensuring the long-term stability and high airtightness of the pipeline.

[0126] In this stage, the vacuum pressure needs to be gradually reduced to return the inside of the pipeline to normal pressure. At the same time, low-temperature air is introduced to reduce the pipeline temperature in a uniform and controlled manner. The whole process is mainly divided into the following steps:

[0127] Step 1: Gradually release the negative pressure and stabilize and restore normal pressure. The intelligent control unit detects the current negative pressure value and confirms the current internal pressure of the pipeline (usually between 0.06 and 0.09 MPa). Then, the vent of the pipeline plug is gradually and slowly opened further (50% opening). A phased exhaust strategy is adopted to allow external air to gradually flow back into the pipeline instead of releasing the negative pressure all at once. When the pressure returns to ≥95 kPa (close to atmospheric pressure), enter the next stage.

[0128] Step 2: The cooling fan is started, and at the same time, the vent of the pipe plug is further opened (70% opening). The air intake duct of the pipe connection structure introduces cooling air at 5 to 25°C. After the temperature stabilizes, the system automatically turns off the cooling fan and the vent opening is gradually reduced to allow the inside of the pipe to reach a stable state to complete the cooling process.

[0129] The beneficial effects of the present invention are: drying the pipeline by synergistically drying it with vacuum negative pressure and high-frequency pulse hot air, which greatly improves the efficiency of pipeline drying, reduces residual moisture, and ensures the long-term stability of the hydrogen energy system;

[0130] By synergistically drying with vacuum negative pressure and high-frequency pulsed hot air, the evaporation rate of moisture inside the pipeline is increased, effectively preventing problems such as local corrosion, icing, and hydrogen embrittlement of the pipeline. At the same time, an intelligent control unit is used to monitor humidity, temperature, and pressure in real time, and dynamically adjust the air extraction rate and hot air flow rate to ensure that the drying process is efficient and controllable. Compared with traditional natural air drying or low-temperature heating drying methods, the present invention avoids the situation of high temperature affecting the surface performance of stainless steel, and at the same time improves the pipeline cleanliness, hydrogen embrittlement resistance, and long-term airtightness, meeting the strict requirements of the hydrogen energy system for high stability, high safety, and high reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0131] Figure 1 It is a schematic structural diagram of an embodiment of the invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0132] To clearly illustrate the technical features of the present solution, the present solution will be described below through specific embodiments.

[0133] Refer Figure 1 ,

[0134] Embodiment 1

[0135] An electrolytic water hydrogen production pipeline CMP pretreatment drying device includes a drying device and a support conveyor frame arranged on one side of the drying device;

[0136] The drying device includes a vacuum negative pressure system, a high-frequency pulsed hot air system, an intelligent control unit, and a pipeline connection structure;

[0137] The drying process includes the following steps:

[0138] S1. Pipeline connection and plugging: Place the hydrogen production pipeline on the support conveyor frame and transport it to the position of the drying device. Then, dock one end of the hydrogen production pipeline with the pipeline connection structure of the drying device, and seal the other end with a pipeline plug;

[0139] S2. Pipeline airtightness detection: Start the vacuum negative pressure system for airtightness detection;

[0140] S3. Vacuum negative pressure drying: Start the vacuum negative pressure system to extract the moisture inside the pipeline;

[0141] S4. High-frequency pulsed hot air drying: Start the high-frequency pulsed hot air system to dry the inside of the hydrogen production pipeline;

[0142] S5. Cooling and restoring normal pressure: Gradually reduce the negative pressure to make the inside of the pipeline return to normal atmospheric pressure, and introduce low-temperature air for cooling.

[0143] Embodiment 2

[0144] An electrolyzed water hydrogen production pipeline CMP pretreatment drying device, comprising a drying device and a support conveyor frame arranged on one side of the drying device;

[0145] The drying device includes a vacuum negative pressure system, a high-frequency pulse hot air system, an intelligent control unit and a pipeline connection structure;

[0146] The drying process includes the following steps:

[0147] S1. Pipeline connection and plugging: Place the hydrogen production pipeline on the support conveyor frame and transport it to the position of the drying device. Then, dock one end of the hydrogen production pipeline with the pipeline connection structure of the drying device, and seal the other end with a pipeline plug;

[0148] S2. Pipeline airtightness detection: Start the vacuum negative pressure system for airtightness detection;

[0149] S3. Vacuum negative pressure drying: Start the vacuum negative pressure system to extract the moisture inside the pipeline;

[0150] S4. High-frequency pulse hot air drying: Start the high-frequency pulse hot air system to dry the inside of the hydrogen production pipeline;

[0151] S5. Cooling and restoring normal pressure: Gradually reduce the negative pressure to make the inside of the pipeline return to normal atmospheric pressure, and introduce low-temperature air for cooling.

[0152] The vacuum negative pressure system includes a vacuum pump, a water vapor separator and a negative pressure regulating valve;

[0153] The vacuum pump is connected to the water vapor separator through a pipeline, the air outlet end of the water vapor separator is connected to the negative pressure regulating valve, and the output end of the negative pressure regulating valve is connected to the pipeline connection structure through a pipeline.

[0154] The high-frequency pulse hot air system includes a high-temperature pulse blower, a pulse controller and a wind pressure regulating valve;

[0155] The air outlet end of the high-temperature pulse blower is connected to the pulse controller, the pulse controller controls the air flow intensity through the wind pressure regulating valve, and the output end of the wind pressure regulating valve is connected to the pipeline connection structure through a pipeline.

[0156] The pipeline connection structure includes a communication chamber. One side of the communication chamber is connected to the output ends of the negative pressure regulating valve and the wind pressure regulating valve. The other side of the communication chamber is provided with a connecting pipe. An annular front-end sealing plate is arranged on the periphery of the end of the connecting pipe. A plurality of gas diversion plates are arranged in parallel in the communication chamber.

[0157] An air inlet pipe is arranged on the side wall of the communication chamber, and the air inlet pipe is connected to a cooling fan.

[0158] An exhaust pipe is arranged on the pipeline plug, and a solenoid valve is arranged on the exhaust pipe;

[0159] Preferably, the pipe plug includes a sealing plate, a limiting stud is arranged on the side surface of the sealing plate, a sealing gasket is arranged on the sealing plate around the limiting stud, and the size of the limiting stud is smaller than the size of the pipe.

[0160] During plugging, the limiting stud is inserted into the pipe, the sealing plate abuts against the end of the pipe to form a plug, side plates are arranged on both sides of the sealing plate, the side plates are arranged on the frame body of the support conveyor through bolts, long strip installation grooves are formed in the frame body of the support conveyor, and installation nuts are arranged at the ends of the bolts passing through the long strip installation grooves.

[0161] The intelligent control unit includes: a humidity monitoring module, a temperature monitoring module, a pressure monitoring module, a wind speed monitoring module and a low-temperature air flow monitoring module.

[0162] The humidity monitoring module is expressed as:

[0163]

[0164] Wherein:

[0165] H is the relative humidity inside the pipe;

[0166] P sat is the saturated water vapor pressure at the current temperature;

[0167] P v is the partial pressure of water vapor inside the pipe;

[0168] α1 is the contribution coefficient of negative pressure evaporation to the humidity decrease;

[0169] α2 is the contribution coefficient of wind speed disturbance to the humidity decrease;

[0170] α3 is the contribution coefficient of hot air heating to the humidity decrease.

[0171] Control target:

[0172] H final ≤5%;

[0173] That is, the humidity is reduced to below 5% to ensure complete drying;

[0174] [[ID=5l]]

[0175] Wherein:

[0176] T pipe (t) is the internal temperature of the pipe;

[0177] T init %is the initial temperature;

[0178] Q air is the heat transferred to the pipe;

[0179] mpipe is the pipeline quality;

[0180] C p is the specific heat capacity of the pipeline material;

[0181] λ c is the heat loss coefficient.

[0182] Control objective:

[0183] T pipe ∈[80°C, 120°C];

[0184] That is, ensure that the internal temperature of the pipeline is between 80 - 120°C to optimize the water evaporation rate;

[0185] The pressure monitoring module is expressed as:

[0186] 0.06 ≤ P v (t) ≤ 0.09 Mpa

[0187]

[0188] Where:

[0189] P v (t) is the partial pressure of water vapor inside the pipeline;

[0190] P v0 is the initial partial pressure of water vapor;

[0191] is the pumping rate of the vacuum pump;

[0192] H target is the target humidity;

[0193] Control objective:

[0194] 0.06 ≤ P v (t) ≤ 0.09 Mpa;

[0195] That is, maintain the internal negative pressure of the pipeline between 0.06 - 0.09 Mpa to ensure effective dehumidification without damaging the pipeline;

[0196] The wind speed monitoring module is expressed as:

[0197]

[0198] Where:

[0199] V air is the wind speed inside the pipeline;

[0200] e H = H - H target is the humidity error;

[0201] K p ,K i ,K d are the PID control parameters;

[0202] γ1 and γ2 are disturbance optimization coefficients;

[0203] Control objective:

[0204] 5 ≤ Vair(t) ≤ 20 m / s;

[0205] That is, to ensure a moderate wind speed, avoid local overheating or overcooling, and improve drying uniformity;

[0206] The low-temperature air flow monitoring module is expressed as:

[0207]

[0208] Where:

[0209] Q cool (t) is the flow rate of the cooling air;

[0210] λ1 and λ2 are cooling rate parameters;

[0211] V cool is the wind speed of the cooling air;

[0212] Control objective:

[0213] Q cool (t) ≥ Q min ;

[0214] That is, to ensure sufficient cooling air volume and avoid too fast or too slow a drop in pipeline temperature.

[0215] The drying process includes the following steps:

[0216] S1. Pipeline connection and sealing. Connect one end of the hydrogen production pipeline to the connecting pipe of the drying device (sealing is formed through the front-end annular sealing plate), and close the other end with a pipeline plug. The pipeline plug and the front-end annular sealing plate form a seal for the hydrogen production pipeline, and at the same time, close all ventilation valves;

[0217] S2. Pipeline airtightness detection. Start the vacuum negative pressure system for airtightness detection. Start the vacuum pump and gradually extract the air inside the pipeline to create a negative pressure environment. Close the vacuum pump (keep the pipeline closed) and observe whether the internal pressure of the pipeline changes over time;

[0218] The pipeline airtightness detection includes the following steps:

[0219] (1) Vacuum pumping and establishing negative pressure:

[0220] Start the vacuum pump and gradually extract the air inside the pipeline to create a negative pressure environment of 0.06 - 0.09 MPa;

[0221] Pressure stability calculation:

[0222] P init = P atm - ΔP;

[0223] Where:

[0224] P init is the initial pressure after the establishment of the negative pressure system;

[0225] P atm is the ambient atmospheric pressure;

[0226] ΔP is the target negative pressure value (0.06 - 0.09 MPa);

[0227] (4) Turn off the vacuum pump and monitor the pressure change

[0228] Turn off the vacuum pump (keep the pipeline closed) and observe whether the pressure inside the pipeline changes with time;

[0229] [[ID=�5]]Measure the pressure change rate inside the pipeline:

[0230]

[0231] Where:

[0232] L is the leakage rate (unit: Pa / s);

[0233] P is the pressure inside the pipeline;

[0234] t is the time;

[0235] dP / dt: represents the differential of pressure P with respect to time t, that is, the rate of pressure change per unit time;

[0236] Sealing judgment criterion:

[0237] L ≤ L max ;

[0238] L max is the acceptable leakage rate (such as 0.5 Pa / s);

[0239] (5) Evaluate the sealing performance

[0240] If L ≤ Lmax, it means the pipeline has good sealing performance, the test passes, and proceed to step S3;

[0241] If L > Lmax, it means there is a leakage in the pipeline, and it is necessary to further check the sealing components and perform repairs;

[0242] S3. Pipeline drying treatment, which is carried out by combining vacuum negative pressure drying and high-frequency pulse hot air drying. Start the vacuum negative pressure system to extract the moisture inside the pipeline, and start the high-frequency pulse hot air system to dry the inside of the hydrogen production pipeline;

[0243] It includes three treatment periods:

[0244] Initial stage (the vacuum negative pressure system starts first, the high-frequency pulse hot air drying has not started yet, and the pipeline plugs remain closed)

[0245] The vacuum negative pressure system starts, forming a negative pressure of 0.06 - 0.09 MPa, causing the moisture inside the pipeline to start evaporating. The water vapor separator operates to discharge the moisture extracted by the negative pressure, ensuring that the water vapor will not accumulate in the vacuum pump;

[0246] When the humidity drops below 70%, it enters the next stage;

[0247] At this time, the high-frequency pulse hot air system has not started yet, mainly relying on the low-temperature evaporation effect of the negative pressure to reduce the initial moisture content;

[0248] Middle stage (the vacuum negative pressure system continues to operate, the high-frequency pulse hot air drying starts gradually, and the solenoid valve at the end of the exhaust pipe of the pipeline plug is controlled to open, allowing a small amount of air to pass through to optimize the air flow disturbance)

[0249] The high-temperature pulse fan starts, providing high-temperature pulse hot air at 80 - 120 °C, increasing the temperature inside the pipeline and accelerating the evaporation rate of the remaining moisture;

[0250] The air flow distribution plate enables the hot air to be evenly distributed throughout the pipeline;

[0251] The vacuum negative pressure system continues to operate, but the air extraction rate gradually decreases to ensure that the hot air can act fully inside the pipeline without being drawn away too quickly. At the same time, the solenoid valve vent of the pipeline plug is slightly opened (20% opening) to ensure that part of the moisture is discharged with the hot air. The vacuum pump continues to operate (the air extraction rate is reduced to 30%), the hot air system continues to heat, the temperature is 80 - 120 °C, and the humidity drops to ≤10%, entering the later stage;

[0252] During this period, the intelligent control unit dynamically adjusts the wind speed and negative pressure intensity to ensure the combined action of the hot air and negative pressure, improving the drying efficiency. The vacuum negative pressure drying (vacuum negative pressure system) and high-frequency pulse hot air drying (high-frequency pulse hot air drying) are partially overlapped to improve the drying uniformity and ensure the complete evaporation of the residual moisture;

[0253] Later stage (the vacuum negative pressure system stops, the high-frequency pulse hot air drying independently completes the drying, and the vent of the pipeline plug is further opened)

[0254] Gradually shut down the vacuum negative pressure system to avoid excessive extraction affecting the residence time of the hot air. The pulse hot air continues to act to ensure that the surface and interior of the pipe fully meet the set drying standards.

[0255] The vent of the pipe plug is further opened (35% opening) to control the rate of hot air discharge and ensure that the water vapor is completely discharged.

[0256] When the intelligent monitoring system detects that the humidity reaches the drying target value, the high-frequency pulse hot air system gradually reduces the fan power and prepares to enter the cooling stage;

[0257] During this period, vacuum negative pressure drying (vacuum negative pressure system) is completely stopped, and high-frequency pulse hot air drying independently completes the final drying work to ensure that the final moisture is completely removed;

[0258] Finally, step S5 is entered to cool down and restore normal pressure;

[0259] S5. Cooling and restoring normal pressure: gradually reduce the negative pressure to restore the normal atmospheric pressure inside the pipeline, and introduce low-temperature air for cooling;

[0260] The main goal of the S5 (cooling and restoring normal pressure) stage is to stabilize and restore the internal pressure of the pipeline and accurately control the cooling rate to prevent thermal stress, microcracks or local deformation of the material caused by sudden temperature drops, thereby ensuring the long-term stability and high airtightness of the pipeline.

[0261] In this stage, the vacuum pressure needs to be gradually reduced to return the inside of the pipeline to normal pressure. At the same time, low-temperature air is introduced to reduce the pipeline temperature in a uniform and controlled manner. The whole process is mainly divided into the following steps:

[0262] Step 1: Gradually release the negative pressure and stabilize and restore normal pressure. The intelligent control unit detects the current negative pressure value and confirms the current internal pressure of the pipeline (usually between 0.06 and 0.09 MPa). Then, the vent of the pipeline plug is gradually and slowly opened further (50% opening). A phased exhaust strategy is adopted to allow external air to gradually flow back into the pipeline instead of releasing the negative pressure all at once. When the pressure returns to ≥95 kPa (close to atmospheric pressure), enter the next stage.

[0263] Step 2: The cooling fan is started, and at the same time, the vent of the pipe plug is further opened (70% opening). The air intake duct of the pipe connection structure introduces cooling air at 5 to 25°C. After the temperature stabilizes, the system automatically turns off the cooling fan and the vent opening is gradually reduced to allow the inside of the pipe to reach a stable state to complete the cooling process.

[0264] The technical features not described in the present invention can be achieved by or adopted from the prior art, and will not be elaborated herein. Of course, the above description is not a limitation to the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by those of ordinary skill in the art within the essence of the present invention should also fall within the protection scope of the present invention.

Claims

1. An electrolytic water hydrogen production pipeline CMP pretreatment drying device, characterized in that, It includes a drying device and a support conveyor rack arranged on one side of the drying device; The drying device includes a vacuum negative pressure system, a high-frequency pulse hot air system, an intelligent control unit and a pipeline connection structure; The drying process includes the following steps: S1. Pipeline connection and plugging: Place the hydrogen production pipeline on the support conveyor rack and transport it to the position of the drying device. Then, dock one end of the hydrogen production pipeline with the pipeline connection structure of the drying device, and seal the other end with a pipeline plug; S2. Pipeline airtightness detection: Start the vacuum negative pressure system for airtightness detection; S3. Vacuum negative pressure drying: Start the vacuum negative pressure system to extract the moisture inside the pipeline; S4. High-frequency pulse hot air drying: Start the high-frequency pulse hot air system to dry the inside of the hydrogen production pipeline; S5. Cooling and returning to normal pressure: Gradually reduce the negative pressure to make the inside of the pipeline return to normal atmospheric pressure, and introduce low-temperature air for cooling.

2. The electrolytic water hydrogen production pipeline CMP pretreatment drying device according to claim 1, characterized in that, The vacuum negative pressure system includes a vacuum pump, a water vapor separator and a negative pressure regulating valve; The vacuum pump is connected to the water vapor separator through a pipeline. The air outlet end of the water vapor separator is connected to the negative pressure regulating valve, and the output end of the negative pressure regulating valve is connected to the pipeline connection structure through a pipeline.

3. The electrolytic water hydrogen production pipeline CMP pretreatment drying device according to claim 2, wherein, The high-frequency pulse hot air system includes a high-temperature pulse fan, a pulse controller and a wind pressure regulating valve; The air outlet end of the high-temperature pulse fan is connected to the pulse controller. The pulse controller controls the air flow intensity through the wind pressure regulating valve, and the output end of the wind pressure regulating valve is connected to the pipeline connection structure through a pipeline.

4. The electrolytic water hydrogen production pipeline CMP pretreatment drying device according to claim 3, characterized in that, The pipeline connection structure includes a communication chamber. One side of the communication chamber is connected to the output ends of the negative pressure regulating valve and the wind pressure regulating valve. On the other side of the communication chamber, there is a connecting pipe. An annular front-end plugging plate is arranged on the periphery of the end of the connecting pipe. A number of gas distribution plates are arranged in parallel in the communication chamber.

5. The electrolytic water hydrogen production pipeline CMP pretreatment drying device according to claim 4, characterized in that, An air inlet pipeline is arranged on the side wall of the communication chamber, and the air inlet pipeline is connected to a cooling fan.

6. The electrolytic water hydrogen production pipeline CMP pretreatment drying device according to claim 5, characterized in that, An exhaust pipe is arranged on the pipeline plug, and an electromagnetic valve is arranged on the exhaust pipe.

7. The electrolytic water hydrogen production pipeline CMP pretreatment drying device according to claim 6, characterized in that, The intelligent control unit includes: a humidity monitoring module, a temperature monitoring module, a pressure monitoring module, a wind speed monitoring module and a low-temperature air flow monitoring module.

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