Cleaning device and cleaning method for plate heat exchanger

Abstract

The invention relates to a cleaning device and method for a plate heat exchanger. The cleaning device comprises an electromagnetic pulse circulation cleaning machine, the plate heat exchanger, a water source, an air source and a cleaning liquid tank. A water inlet and a water outlet of the plate heat exchanger are respectively connected with a seawater inlet pipe and a seawater outlet pipe, a first cleaning pipe of the electromagnetic pulse circulating cleaning machine is connected with the seawater outlet pipe, and a second cleaning pipe of the electromagnetic pulse circulating cleaning machine is connected with the seawater inlet pipe; an air inlet of the electromagnetic pulse circulation cleaning machine is connected with an air outlet pipe of the air source, a water inlet of the electromagnetic pulse circulation cleaning machine is connected with a water outlet pipe of the water source, and a liquid outlet pipe of the cleaning liquid tank is connected to the water outlet pipe. On the premise that the seawater desalination device is not stopped and the plate heat exchanger is not disassembled, sludge, dirt and marine organisms which are polluted and blocked in the plate heat exchanger can be efficiently cleaned, and the heat exchange efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of heat exchanger cleaning, and in particular to a cleaning device and a cleaning method for a plate heat exchanger. Background Art

[0002] Low-temperature multi-effect distillation desalination technology (LT-MED) refers to a desalination technology in which the maximum evaporation temperature of brine is lower than 70°C under vacuum conditions. It is characterized by connecting a series of horizontal tube spray falling film evaporators in series, using a certain amount of steam input through multiple evaporations and condensations. The evaporation temperature of the latter effect is lower than that of the previous effect, thereby obtaining a desalination process of distilled water with multiple times the amount of steam. This technology has high requirements for water temperature control, so a large number of heat exchange equipment are installed in the system. Plate heat exchangers are widely used in low-temperature multi-effect distillation desalination devices due to their advantages such as small footprint, high heat exchange efficiency, and investment savings. During the operation of the plate heat exchanger, due to the eutrophication of seawater, a large amount of biological slime will clog the plate heat exchanger (see Figure 2 ), the fouling of plate heat exchangers is more prone to scaling and sediment deposition, resulting in a significant decrease in heat exchange effect, increased pressure drop, and increased energy consumption and corrosion risk of seawater desalination equipment; and long-term scale deposition will cause corrosion and leakage of the heat exchanger, shortening the service life of the heat exchanger.

[0003] The existing method to solve the above problems is to dismantle the plate heat exchanger and remove the heat exchanger plate for high-pressure water washing and chemical cleaning. Dismantling and cleaning face difficulties such as high cleaning costs, long cleaning period, a large number of sealing points, and high requirements for reinstallation process. In addition, due to the single series design of the plate heat exchanger in the seawater desalination system, the dismantling of the plate heat exchanger in the seawater desalination system requires a long time to shut down the seawater desalination device. This technical solution will seriously affect the water supply of end users. Chemical cleaning is to soak the heat exchanger plate with hydrochloric acid or aminosulfonic acid. The effect monitoring method is only visual, and there is no technical supervision plan, which can easily cause the heat exchanger plate to be under-washed or over-washed.

[0004] Therefore, it is necessary to study an online cleaning device and method for a low-temperature multi-effect distillation seawater desalination plate heat exchanger to solve the above-mentioned cleaning problems. Summary of the invention

[0005] The purpose of the present invention is to provide a cleaning device and a cleaning method for a plate heat exchanger, which can not only efficiently clean the sludge, dirt and marine organisms blocked inside the plate heat exchanger without stopping the operation of the seawater desalination device and dismantling the plate heat exchanger, thereby improving the heat exchange efficiency, but also improve the maintenance efficiency, save maintenance costs and extend the service life of the equipment.

[0006] In order to achieve the above-mentioned purpose, the first aspect of the present invention provides a cleaning device for a plate heat exchanger, which includes an electromagnetic pulse circulation cleaning machine, a plate heat exchanger, a water source, an air source and a cleaning liquid tank; the water inlet and the water outlet of the plate heat exchanger are respectively connected to a seawater inlet pipe and a seawater outlet pipe, the first cleaning pipe of the electromagnetic pulse circulation cleaning machine is connected to the seawater outlet pipe, and the second cleaning pipe of the electromagnetic pulse circulation cleaning machine is connected to the seawater inlet pipe; the air inlet of the electromagnetic pulse circulation cleaning machine is connected to the air outlet pipe of the air source, the water inlet of the electromagnetic pulse circulation cleaning machine is connected to the water outlet pipe of the water source, and the liquid outlet pipe of the cleaning liquid tank is connected to the water outlet pipe.

[0007] Optionally, the seawater inlet pipe and the seawater outlet pipe are provided with an inlet valve and an outlet valve respectively; the first cleaning pipe is connected to the inlet end close to the outlet valve, and the second cleaning pipe is connected to the outlet end close to the inlet valve.

[0008] Optionally, the air source is compressed air; and the water source is produced water makeup.

[0009] Optionally, the cleaning liquid tank is filled with chemical cleaning liquid and corrosion inhibitor.

[0010] Optionally, the electromagnetic pulse circulation cleaning machine is further provided with a sewage discharge pipe, and the sewage discharge pipe is connected to a sewage collection tank.

[0011] Optionally, the cleaning device further comprises a pH indicator and a PLC intelligent controller; the pH indicator monitors the pH value of the cleaning liquid; and the PLC intelligent controller controls the electromagnetic pulse circulation cleaning machine.

[0012] A second aspect of the present invention provides a method for cleaning a plate heat exchanger, using the cleaning device provided by the first aspect of the present invention, the cleaning method comprising: S1, after turning on the water source and sending it into the electromagnetic pulse circulation cleaning machine, the plate heat exchanger is first cleaned in the forward direction through the first cleaning pipe, and the plate heat exchanger is first cleaned in the reverse direction through the second cleaning pipe; S2, turn off the water source, open the cleaning liquid tank containing chemical cleaning solution and corrosion inhibitor, the chemical cleaning solution and corrosion inhibitor perform a second forward cleaning on the plate heat exchanger through the first cleaning pipe, and perform a second reverse cleaning on the plate heat exchanger through the second cleaning pipe; S3, close the cleaning liquid tank, open the water source to send water into the electromagnetic pulse circulation cleaning machine, and then perform a third forward cleaning on the plate heat exchanger through the first cleaning pipe, and perform a third reverse cleaning on the plate heat exchanger through the second cleaning pipe.

[0013] Optionally, the waste liquid after the first reverse cleaning and the third reverse cleaning is discharged to a sewage collection tank through a sewage pipe, and the chemical waste liquid after the second reverse cleaning is discharged to a cleaning liquid tank for circulating chemical cleaning.

[0014] Optionally, the electromagnetic pulse circulation cleaning machine is controlled by a PLC intelligent controller.

[0015] Optionally, the mass concentration of the chemical washing solution is controlled at 1.2-1.8%, the temperature is controlled at 38-42° C., and the pH value is controlled at 1-1.5; and the mass concentration of the corrosion inhibitor is controlled at 0.3-0.35%.

[0016] Optionally, the chemical washing solution includes one or more of aminosulfonic acid, hydrochloric acid and citric acid, and the corrosion inhibitor includes one or more of inorganic corrosion inhibitor, organic corrosion inhibitor and polymer corrosion inhibitor.

[0017] Optionally, the inorganic corrosion inhibitor includes one or more of chromates, nitrites, silicates, molybdates, tungstates, polyphosphates, and zinc salts; the organic corrosion inhibitor includes one or more of phosphonic acid, phosphonates, phosphinocarboxylic acids, mercaptobenzothiazole, benzotriazole, and sulfonated lignin; the polymer corrosion inhibitor includes one or more of polyethylenes, phosphonocarboxylic acid copolymers, and polyaspartic acid.

[0018] Through the above technical scheme, the present invention directly connects the electromagnetic pulse circulation cleaning machine to the water inlet and outlet pipes of the plate heat exchanger to realize the cleaning of the plate heat exchanger. The device has a simple structure and high integration. The cleaning process uses a combination of electromagnetic pulse cleaning and chemical cleaning. It can not only effectively clean the sludge, dirt and marine organisms blocked inside the plate heat exchanger without stopping the seawater desalination device and dismantling the plate heat exchanger, thereby improving the heat exchange efficiency, but also improve the maintenance efficiency, save maintenance costs and extend the service life of the equipment.

[0019] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present invention but do not constitute a limitation of the present invention. In the accompanying drawings: Figure 1 Schematic diagram of a cleaning device for a plate heat exchanger of the present invention; Figure 2 is a schematic diagram of the plate heat exchanger of the present invention before cleaning; Figure 3 It is a schematic diagram of the plate heat exchanger after cleaning of the present invention.

[0021] Description of Reference Numerals 1-electromagnetic pulse circulation cleaning machine; 2-plate heat exchanger; 3-water source; 4-gas source; 5-cleaning liquid tank; 1-1-first cleaning pipe; 1-2-second cleaning pipe; 2-1-seawater inlet pipe; 2-2-seawater outlet pipe; 2-3-inlet valve; 2-4-outlet valve; 3-1-water outlet pipe; 4-1-gas outlet pipe; 5-1-liquid outlet pipe. DETAILED DESCRIPTION

[0022] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0023] A first aspect of the present invention provides a cleaning device for a plate heat exchanger, the cleaning device comprising an electromagnetic pulse circulation cleaning machine 1, a plate heat exchanger 2, a water source 3, an air source 4 and a cleaning liquid tank 5; the water inlet and the water outlet of the plate heat exchanger 2 are respectively connected to a seawater inlet pipe 2-1 and a seawater outlet pipe 2-2, the first cleaning pipe 1-1 of the electromagnetic pulse circulation cleaning machine 1 is connected to the seawater outlet pipe 2-2, and the second cleaning pipe 1-2 of the electromagnetic pulse circulation cleaning machine 1 is connected to the seawater inlet pipe 2-1; the air inlet of the electromagnetic pulse circulation cleaning machine 1 is connected to the air outlet pipe 4-1 of the air source 4, the water inlet of the electromagnetic pulse circulation cleaning machine 1 is connected to the water outlet pipe 3-1 of the water source 3, and the liquid outlet pipe 5-1 of the cleaning liquid tank 5 is connected to the water outlet pipe 3-1.

[0024] According to the present invention, optionally, an inlet valve 2-3 and an outlet valve 2-4 are respectively provided on the seawater inlet pipe 2-1 and the seawater outlet pipe 2-2; the first cleaning pipe 1-1 is connected to the inlet end close to the outlet valve 2-4, and the second cleaning pipe 1-2 is connected to the outlet end close to the inlet valve 2-3.

[0025] According to the present invention, optionally, the air source 4 is compressed air; the water source 3 is produced water replenishment, and the produced water replenishment comes from a seawater desalination device.

[0026] According to the present invention, optionally, valves are respectively provided on the water outlet pipe 3 - 1 , the air outlet pipe 4 - 1 and the liquid outlet pipe 5 - 1 .

[0027] According to the present invention, optionally, the cleaning liquid tank 5 is filled with chemical cleaning liquid and corrosion inhibitor.

[0028] According to the present invention, optionally, the electromagnetic pulse circulation cleaning machine 1 is further provided with a sewage discharge pipe, and the sewage discharge pipe is connected to the sewage collection tank.

[0029] According to the present invention, optionally, the cleaning device further comprises a pH indicator and a PLC intelligent controller; the pH indicator monitors the pH value of the cleaning liquid during the cleaning process; and the PLC intelligent controller controls the electromagnetic pulse circulation cleaning machine.

[0030] The electromagnetic pulse circulation cleaning machine of the present invention is a high-efficiency online cleaning equipment based on CIP (Clean in Place) technology, which can perform online cleaning work without disassembling the plate heat exchanger, improve heat exchange efficiency, and reduce manual cleaning time and material costs. The electromagnetic pulse circulation cleaning machine combines the structural characteristics of the plate heat exchanger, adopts electromagnetic pulse multiphase flow cleaning technology and chemical cleaning technology, and is connected to the electromagnetic pulse circulation cleaning machine through the fixed pipeline of the plate heat exchanger's own system and the installed cleaning pipeline, to establish a relatively closed cleaning system and sewage discharge system, and uses the PLC intelligent control system to generate pulse waves to flush the plates, so that the desalination device can be quickly cleaned during operation without disassembling the plate heat exchanger.

[0031] A second aspect of the present invention provides a method for cleaning a plate heat exchanger, using the cleaning device provided by the first aspect of the present invention, the cleaning method comprising: S1. After turning on the water source and sending it into the electromagnetic pulse circulation cleaning machine, the plate heat exchanger is first cleaned in the forward direction through the first cleaning pipe, and the plate heat exchanger is first cleaned in the reverse direction through the second cleaning pipe; after the cleaning, the appearance is clear and free of impurities; S2. Turn off the water source, open the cleaning liquid tank containing chemical cleaning solution and corrosion inhibitor, and use the chemical cleaning solution and corrosion inhibitor to perform a second forward cleaning on the plate heat exchanger through the first cleaning pipe, and perform a second reverse cleaning on the plate heat exchanger through the second cleaning pipe; analyze the mass concentration and pH value of the chemical cleaning solution every 0.5h; S3. Close the cleaning liquid tank, open the water source and send it into the electromagnetic pulse circulation cleaning machine, then perform the third forward cleaning of the plate heat exchanger through the first cleaning pipe, and perform the third reverse cleaning of the plate heat exchanger through the second cleaning pipe; after the cleaning, the appearance is clear and free of impurities, and the pH value is ≥4.0.

[0032] According to the present invention, optionally, after the third reverse cleaning of the plate heat exchanger is completed, sodium hydroxide may be added to neutralize the chemical washing liquid, and the pH value may be monitored and controlled at 6 to 9 every hour.

[0033] According to the present invention, optionally, the waste liquid after the first reverse cleaning and the third reverse cleaning is discharged to the sewage collection tank through the sewage pipe, and discharged to the drainage ditch after neutralization treatment; the chemical waste liquid after the second reverse cleaning is discharged to the cleaning liquid tank for circulating chemical cleaning.

[0034] According to the present invention, the electromagnetic pulse circulation cleaning machine can be optionally controlled by a PLC intelligent controller, which can be operated automatically with one-button operation, and is simple and reliable to operate.

[0035] According to the present invention, optionally, the mass concentration of the chemical washing solution is controlled at 1.2-1.8%, preferably at 1.5%, the temperature is controlled at 38-42°C, and the pH value is controlled at 1-1.5; the mass concentration of the corrosion inhibitor is controlled at 0.3-0.35%.

[0036] According to the present invention, optionally, the chemical washing solution includes one or more of aminosulfonic acid, hydrochloric acid and citric acid, and the corrosion inhibitor includes one or more of inorganic corrosion inhibitor, organic corrosion inhibitor and polymer corrosion inhibitor.

[0037] According to the present invention, optionally, the inorganic corrosion inhibitor includes one or more of chromates, nitrites, silicates, molybdates, tungstates, polyphosphates, and zinc salts; the organic corrosion inhibitor includes some heterocyclic compounds containing nitrogen oxides, for example, one or more of phosphonic acid, phosphonates, phosphinocarboxylic acids, mercaptobenzothiazole, benzotriazole, and sulfonated lignin; the polymer corrosion inhibitor includes some oligomeric high molecular chemicals, for example, one or more of polyethylenes, phosphonocarboxylic acid copolymers, and polyaspartic acid.

[0038] Through the above technical scheme, the present invention directly connects the electromagnetic pulse circulation cleaning machine to the inlet and outlet water pipes of the plate heat exchanger to realize the cleaning of the plate heat exchanger. The device has a simple structure and high integration. The cleaning process uses a combination of electromagnetic pulse cleaning and chemical cleaning to perform forward and reverse cleaning. It can not only efficiently clean the sludge, dirt and marine organisms that clog the inside of the seawater desalination device without stopping the operation of the seawater desalination device and dismantling the plate heat exchanger, thereby improving the heat exchange efficiency, but also improve the maintenance efficiency, save maintenance costs, and extend the service life of the equipment.

[0039] The present invention is further illustrated by the following examples, but the present invention is not limited thereto.

[0040] Example 1 This embodiment provides a cleaning device for a plate heat exchanger, such as Figure 1As shown, the cleaning device includes an electromagnetic pulse circulation cleaning machine 1, a plate heat exchanger 2, a water source 3, an air source 4 and a cleaning liquid tank 5; the water inlet and the water outlet of the plate heat exchanger 2 are respectively connected to a seawater inlet pipe 2-1 and a seawater outlet pipe 2-2; the first cleaning pipe 1-1 of the electromagnetic pulse circulation cleaning machine 1 is connected to the seawater outlet pipe 2-2, and the second cleaning pipe 1-2 of the electromagnetic pulse circulation cleaning machine 1 is connected to the seawater inlet pipe 2-1; the seawater inlet pipe 2-1 and the seawater outlet pipe 2-2 are respectively provided with an inlet valve 2-3 and an outlet valve 2-4; the first cleaning pipe 1-1 is connected to the inlet end close to the outlet valve 2-4, and the second cleaning pipe 1-2 is connected to the outlet end close to the inlet valve 2-3; The air inlet of the electromagnetic pulse circulation cleaning machine 1 is connected to the air outlet pipe 4-1 of the air source 4, and the air source 4 is compressed air; the water inlet of the electromagnetic pulse circulation cleaning machine 1 is connected to the water outlet pipe 3-1 of the water source 3, and the water source 3 is seawater desalination water; the liquid outlet pipe 5-1 of the cleaning liquid tank 5 is connected to the water outlet pipe 3-1, and the cleaning liquid tank 5 is filled with chemical cleaning liquid and corrosion inhibitor; The electromagnetic pulse circulation cleaning machine 1 is also provided with a sewage pipe (not shown in the figure), which is connected to the sewage collection tank; the cleaning device also includes a pH indicator (not shown in the figure) and a PLC intelligent controller (not shown in the figure); the pH indicator monitors the pH value of the cleaning liquid during the cleaning process; the PLC intelligent controller controls the electromagnetic pulse circulation cleaning machine.

[0041] Example 2 This embodiment provides a method for cleaning a plate heat exchanger, the cleaning method comprising: S1. After turning on the water source and sending it into the electromagnetic pulse circulation cleaning machine, the plate heat exchanger is first cleaned in the forward direction through the first cleaning pipe, and the plate heat exchanger is first cleaned in the reverse direction through the second cleaning pipe; the waste liquid after cleaning is discharged to the sewage collection tank through the sewage pipe, and discharged to the drainage ditch after neutralization treatment; after cleaning, the appearance is clear and free of impurities; S2. Turn off the water source, open the cleaning liquid tank containing the chemical cleaning liquid aminosulfonic acid and the corrosion inhibitor chromate, and the chemical cleaning liquid and the corrosion inhibitor are used to perform the second forward cleaning of the plate heat exchanger through the first cleaning pipe, and the second reverse cleaning of the plate heat exchanger through the second cleaning pipe; analyze the mass concentration and pH value of the chemical cleaning liquid every 0.5 hours; the chemical waste liquid after cleaning is discharged to the cleaning liquid tank for cyclic chemical cleaning; the mass concentration of the chemical cleaning liquid is controlled at 1.5%, the temperature is controlled at 38~42℃, and the pH value is controlled at 1~1.5; the mass concentration of the corrosion inhibitor is controlled at 0.3~0.35%; S3. Close the cleaning liquid tank, open the water source and send it into the electromagnetic pulse circulation cleaning machine, then perform the third forward cleaning on the plate heat exchanger through the first cleaning pipe, and perform the third reverse cleaning on the plate heat exchanger through the second cleaning pipe; the waste liquid after cleaning is discharged to the sewage collection tank through the sewage pipe, and discharged to the drainage ditch after neutralization treatment; after cleaning, the appearance is clear and free of impurities, and the pH value is ≥4.0.

[0042] The plate heat exchanger is cleaned by the above method, and compared with the plate heat exchanger before cleaning (such as Figure 2 As shown in the figure, the entire plate heat exchanger is very clean inside, and no marine biological debris such as barnacles, shells, algae, or sludge is found. Figure 3 .

[0043] The weight loss method was used to determine the average corrosion rate and total corrosion amount of the corrosion indicator sheet of the cleaning device. The average metal corrosion rate of the titanium test sheet of the corrosion indicator sheet was 0.0078, which is better than the relevant industry standard of 1g / (m 2 ·h), the total corrosion amount is 0.05g / m 2 , better than the industry standard 10g / m 2 .

[0044] The traditional technical solution of disassembling and removing the plate heat exchanger has a labor and spare parts cost of 435,000 yuan / year; the online cleaning method of the plate heat exchanger in this embodiment costs about 30,000 yuan / year, saving about 405,000 yuan per year, and greatly reducing the inspection and maintenance cost of the plate heat exchanger.

[0045] The traditional technical solution of dismantling and removing the plate heat exchanger takes 8 people 10 working days for maintenance, a total of 640 working hours; the online cleaning method of the plate heat exchanger in this embodiment takes 3 people 35 working hours, a total of 105 working hours; each maintenance period is reduced by 535 working hours, and there is no need to shut down the seawater desalination device, which greatly shortens the maintenance period of the plate heat exchanger.

[0046] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0047] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0048] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A cleaning device for a plate heat exchanger, characterized in that: The cleaning device comprises an electromagnetic pulse circulation cleaning machine (1), a plate heat exchanger (2), a water source (3), an air source (4) and a cleaning liquid tank (5); The water inlet and the water outlet of the plate heat exchanger (2) are respectively connected to a seawater inlet pipe (2-1) and a seawater outlet pipe (2-2); the first cleaning pipe (1-1) of the electromagnetic pulse circulation cleaning machine (1) is connected to the seawater outlet pipe (2-2); and the second cleaning pipe (1-2) of the electromagnetic pulse circulation cleaning machine (1) is connected to the seawater inlet pipe (2-1); The air inlet of the electromagnetic pulse circulation cleaning machine (1) is connected to the air outlet pipe (4-1) of the air source (4), the water inlet of the electromagnetic pulse circulation cleaning machine (1) is connected to the water outlet pipe (3-1) of the water source (3), and the liquid outlet pipe (5-1) of the cleaning liquid tank (5) is connected to the water outlet pipe (3-1).

2. The cleaning device according to claim 1, wherein: The seawater inlet pipe (2-1) and the seawater outlet pipe (2-2) are respectively provided with an inlet valve (2-3) and an outlet valve (2-4); The first cleaning pipe (1-1) is connected to an inlet end close to the outlet valve (2-4), and the second cleaning pipe (1-2) is connected to an outlet end close to the inlet valve (2-3).

3. The cleaning device according to claim 1, wherein: The air source (4) is compressed air; the water source (3) is production water.

4. The cleaning device according to claim 1, wherein: The cleaning liquid tank (5) is filled with chemical cleaning liquid and corrosion inhibitor.

5. The cleaning device according to claim 1, wherein: The electromagnetic pulse circulation cleaning machine (1) is also provided with a sewage discharge pipe, which is connected to a sewage collection tank.

6. The cleaning device according to claim 1, wherein: The cleaning device also includes a pH indicator and a PLC intelligent controller; the pH indicator monitors the pH value of the cleaning liquid; and the PLC intelligent controller controls the electromagnetic pulse circulation cleaning machine.

7. A method for cleaning a plate heat exchanger, characterized in that: Using the cleaning device described in claims 1-6, the cleaning method comprises: S1, after turning on the water source and sending it into the electromagnetic pulse circulation cleaning machine, the plate heat exchanger is first cleaned in the forward direction through the first cleaning pipe, and the plate heat exchanger is first cleaned in the reverse direction through the second cleaning pipe; S2, turn off the water source, open the cleaning liquid tank containing chemical cleaning solution and corrosion inhibitor, the chemical cleaning solution and corrosion inhibitor perform a second forward cleaning on the plate heat exchanger through the first cleaning pipe, and perform a second reverse cleaning on the plate heat exchanger through the second cleaning pipe; S3, close the cleaning liquid tank, open the water source to send water into the electromagnetic pulse circulation cleaning machine, and then perform a third forward cleaning on the plate heat exchanger through the first cleaning pipe, and perform a third reverse cleaning on the plate heat exchanger through the second cleaning pipe.

8. The cleaning method according to claim 7, wherein: The waste liquid after the first reverse cleaning and the third reverse cleaning is discharged to the sewage collection tank through the sewage pipe, and the chemical waste liquid after the second reverse cleaning is discharged to the cleaning liquid tank for circulating chemical cleaning.

9. The cleaning method according to claim 7, wherein: The electromagnetic pulse circulation cleaning machine is controlled by a PLC intelligent controller.

10. The cleaning method according to claim 7, wherein: The mass concentration of the chemical washing solution is controlled at 1.2-1.8%, the temperature is controlled at 38-42°C, and the pH value is controlled at 1-1.5; the mass concentration of the corrosion inhibitor is controlled at 0.3-0.35%; The chemical washing liquid includes one or more of aminosulfonic acid, hydrochloric acid and citric acid, and the corrosion inhibitor includes one or more of inorganic corrosion inhibitor, organic corrosion inhibitor and polymer corrosion inhibitor; The inorganic corrosion inhibitor includes one or more of chromate, nitrite, silicate, molybdate, tungstate, polyphosphate, and zinc salt; the organic corrosion inhibitor includes one or more of phosphonic acid, phosphonate, phosphinocarboxylic acid, mercaptobenzothiazole, benzotriazole, and sulfonated lignin; the polymer corrosion inhibitor includes one or more of polyethylene, phosphonocarboxylic acid copolymer, and polyaspartic acid.

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