Ferrous sulfide cleaning method based on ferrous sulfide cleaning device

Abstract

The invention relates to a ferrous sulfide cleaning method based on a ferrous sulfide cleaning device, and belongs to the technical field of petrochemical engineering treatment equipment. The method specifically comprises the steps that inspection preparation work before operation is conducted, a PLC control system injects industrial water and passivating agent liquid into a dissolving tank according to a given proportion, an electric pump B is started, the electric pump B can continuously supply liquid into equipment to be cleaned, meanwhile, a solution at the bottom of the equipment to be cleaned flows back into the dissolving tank, and the solution circularly enters and exits from the equipment to be cleaned; and according to the detected parameter change of the iron ion on-line monitor, the PLC control system automatically judges that the cleaning is finished when the change of the iron ion content does not exceed 10% in the latest two hours after the circulating cleaning is performed for 12 hours. The problems that manual matching control of industrial water and passivating agent liquid is not accurate, the iron ion content and the PH value cannot be analyzed on line, whether passivation cleaning is qualified or not cannot be automatically judged, and manual labor investment is large are solved.

Description

Technical Field

[0001] The present invention relates to a method for cleaning iron sulfide based on an iron sulfide cleaning device, and belongs to the technical field of petrochemical processing equipment. Background Art

[0002] In the process of petroleum processing, due to the presence of sulfur-containing substances in crude oil and its fractions, a large amount of iron sulfide is easily generated during the operation of the device, which corrodes the equipment and causes leakage of equipment pipelines. More seriously, when the equipment is opened for maintenance during shutdown, the iron sulfide will quickly oxidize and spontaneously combust with oxygen, thus causing fire and explosion accidents, posing great potential hazards to safety maintenance and equipment protection. For safety and environmental protection, it is very necessary to remove harmful substances such as iron sulfide and hydrogen sulfide on refining equipment and pipelines before maintenance. Although existing desulfurization technologies and anti-corrosion technologies can achieve good preventive effects, they still cannot completely avoid the generation of sulfides. How to deal with the sulfur corrosion products generated on the surface of equipment and pipelines and eliminate potential safety hazards remains the main problem facing us. The methods for removing sulfur corrosion products generally fall into mechanical cleaning methods and chemical cleaning methods. The mechanical cleaning method mainly uses special machinery to clean the corrosion products on the surface of the equipment, which is easy to damage the equipment, but is friendly to the environment and has high efficiency. Chemical cleaning includes caustic washing, acid washing, organic solvent washing, and mixed solution washing composed of surfactants, alkalis, organic solvents, etc. according to the different physical and chemical properties of the scale layer, with different costs and effects.

[0003] Iron sulfide is the product of the corrosion of sulfur and its sulfides in oil products with iron and its oxides. The sulfur in these oil products mainly comes from crude oil, and some also come from additives in the crude oil processing process. Active sulfur has high corrosion activity and can directly react with metals to cause metal corrosion, such as elemental sulfur, hydrogen sulfide (H2S), and mercaptan (R-SH); inactive sulfur refers to those sulfides that usually cannot directly react with metals, such as thioether (R-S-R'), disulfide (RS-S-R'), cyclic sulfide, alkyl sulfoxide, thiophene, etc. However, in the catalytic cracking reaction during the crude oil refining process, these so-called inactive sulfur organic sulfides will decompose to form active sulfur such as S and H2S, and these active sulfur will react with iron or iron compounds under different conditions to form iron sulfide or other sulfides of iron.

[0004] First, at high temperatures (350 - 400 °C), sulfur can directly react with metals to form iron sulfide, and H2S can start to react with Fe at 200 °C. Some mercaptans contained in crude oil can also directly react with iron at high temperatures (above 200 °C) to produce iron sulfide corrosion products.

[0005] Second, at high temperatures, H2S can decompose, and the resulting elemental sulfur has high activity and reacts extremely strongly with Fe.

[0006] Thirdly, when SO2 and CO coexist in the flue gas pipeline of the fluid catalytic cracking unit at high temperature (400 - 600 °C): SO2 + 2CO → 2CO2 + S; S + Fe → FeS.

[0007] Fourthly, the chlorides contained in crude oil produce HCl during the hydrogenation process and high-temperature hydrolysis process, and act synergistically with H2S in the crude oil.

[0008] Fifthly, during the corrosion when naphthenic acid coexists with H2S at high temperature, the FeS protective film formed by H2S corrosion on the metal surface during the refining process of sour crude oil forms oil-soluble Fe(RCOO)2 under the action of naphthenic acid, exposing and brightening the metal surface. At the same time, the secondary product H2S formed can participate in the corrosion process at high temperature, playing a role in replenishment and regeneration.

[0009] Sixthly, atmospheric corrosion reaction generates iron sulfide. Since the device is shut down for a long time and the internal components of the equipment are exposed to the air for a long time, atmospheric corrosion will occur and rust will be generated. Since the rust is not easy to be completely removed, it will react with hydrogen sulfide during the production process to generate iron sulfide. This reaction is relatively easy to proceed. Due to the long-term shutdown, the devices with poor anti-corrosion are more likely to generate iron sulfide.

[0010] In the refining process, due to the combined action of electrochemical corrosion, chemical corrosion, microbial corrosion and oxidation corrosion, the opportunity for the formation of iron sulfide always exists. The higher the sulfur content of the oil product, the greater the probability of generating iron sulfide. The iron sulfide generated in the initial stage of the oil product processing covers the surface of the equipment densely and firmly, providing a certain protection for the equipment. However, due to the combined action of various corrosion systems and the erosion of gas-liquid phase fluids, the dense iron sulfide will peel off and settle at the bottom of trays, liquid receiving tanks, packings, etc. as the oil product flows. Some iron sulfide still adheres to the surface of the equipment, and heavy components such as oil residues, coke powder, and coke asphaltene are also likely to deposit in the above areas, wrapping the iron sulfide. During the process of shutdown process treatment of the device, such as steam purging and water washing, these deposits are difficult to be removed. When the equipment is opened and exposed to air, the iron sulfide will spontaneously combust, releasing a large amount of heat rapidly, and at the same time, it will ignite the organic substances such as the wrapped oil residues and coke powder. In the petrochemical industry, incidents of tower burning and explosion caused by the spontaneous combustion of iron sulfide are not uncommon. This has always been a major problem for refinery enterprises at home and abroad.

[0011] With the progress of domestic refining technology and the improvement of management level, the equipment is developing in the direction of long operation cycles. However, there is always a contradiction between the deterioration of crude oil quality and long operation cycles. Due to the combined effects of these two aspects, it has become a necessary process to remove the dirt accumulated in the equipment during the shutdown stage of the unit. This can not only eliminate the unsafe factors when the equipment is opened (such as the spontaneous combustion of iron sulfide damaging the equipment), but also create a good maintenance environment (such as removing malodorous substances like hydrogen sulfide), and can also restore the original functions of the equipment (such as removing crystalline scale and heavy oil dirt).

[0012] Usually, refineries have a set of procedures for clearing oil before equipment shutdown and maintenance, including steam purging, water flushing, etc. However, because there is no systematic chemical cleaning procedure, only light components can often be removed, but heavy oil dirt and FeS cannot be removed; the sludge, slurry, residue oil, and coke in the system cannot be completely removed either. Moreover, due to dead ends left by steam purging and water flushing, the safety procedure standards cannot be met. Therefore, it is very necessary to remove harmful substances such as iron sulfide and hydrogen sulfide on refining equipment and pipelines before maintenance. However, current industrial cleaning equipment is mainly manually operated, which not only has a high working intensity but also low efficiency. First of all, manually operated cleaning equipment requires a large amount of manpower and time. For large industrial equipment, it may require several people or even dozens of people to operate, and the cleaning process may take several hours or even several days, which to a certain extent increases the cost of industrial production.

[0013] Secondly, traditional cleaning equipment often cannot achieve an accurate ratio of industrial water to passivating agent solution. During the cleaning process, it is necessary to adjust the ratio of industrial water to passivating agent solution according to various factors such as different working environments, the material of the equipment, its usage status, the type and quantity of other compound impurities accumulated, etc., in order to achieve the best cleaning effect. In addition, due to inaccurate estimation of the dosage of the passivating agent by manual calculation and incomplete consideration of various factors, it is often difficult to achieve an accurate ratio. A high proportion of the passivating agent increases the cleaning cost, while a low proportion affects the cleaning effect.

[0014] Therefore, there are many problems with existing cleaning equipment, such as being unable to achieve an accurate ratio of industrial water to passivating agent solution and unable to be adjusted according to different working environments and requirements. These problems have restricted the effectiveness and application scope of cleaning equipment and brought many troubles to industrial production. How to solve these problems and improve the automation degree, accuracy, and flexibility of cleaning equipment is an important direction for the development of current industrial cleaning equipment technology.

[0015] During the cleaning process, the ratio of industrial water to the passivating agent solution is an important factor affecting the cleaning effect. To achieve an ideal cleaning effect, quantitative control of the passivating agent is required. For example, by online monitoring the iron ion content and pH value in the cleaning solution, the passivating agent can be adjusted in real time to achieve the best cleaning effect. However, for existing cleaning equipment, after manual sampling of the circulating cleaning solution at regular intervals, it is sent to a laboratory for chemical analysis and detection of various parameter indicators of the circulating cleaning solution. This not only consumes time and effort but also affects the accuracy of the chemical analysis results of the circulating cleaning solution.

[0016] In the prior art, the patent application number is CN201310114860.3, and the invention name is "A Ferrous Sulfide Passivating Agent and Its Preparation Method", which is a passivating agent with a fast reaction speed, high efficiency, non-toxicity, and can be directly discharged to a sewage treatment plant. This passivating agent is made of Tween 80, citric acid, sodium dodecyl sulfate, potassium permanganate, and secondary deionized water.

[0017] For a Chinese invention patent application, the publication number is CN 113617766 A, and the invention name is "Double Horizontal Pump Mechanical Cleaning Device, Process and Layout System for Oil Storage Tanks". The cleaning device mainly consists of a vacuum suction tank, a gas-liquid separation tank, a horizontal centrifugal pump, a heat exchanger, an automatic control system, and related instrument pipe fittings, etc.

[0018] For a Chinese invention patent, the announcement number is CN102908888B, and the invention name is "Ferrous Sulfide and Hydrogen Sulfide Gas Containing Cleaning and Passivating Device, Method and Application". It is a ferrous sulfide and hydrogen sulfide gas containing cleaning and passivating device, which includes: a liquid dispensing tank truck, a passivating cleaning agent supply device, and a water supply device. The passivating cleaning agent supply device and the water supply device are connected to the liquid dispensing tank of the liquid dispensing tank truck through pipelines, and are used to supply passivating cleaning agent and water to the liquid dispensing tank of the liquid dispensing tank truck.

[0019] For a Chinese invention patent application, the publication number is CN 107472732 A, and the invention name is "Liquid Hazardous Chemicals Skid-mounted Cleaning Device and Method". The invention provides a liquid hazardous chemicals skid-mounted cleaning device and method. This liquid hazardous chemicals skid-mounted cleaning device includes a tank body, a barrier layer, a polymer explosion-proof material, a first pump, a second pump, a water tank, a cleaning solution, and a filter. Among them, the barrier layer is arranged in the tank body, and the tank body is divided into an upper space and a lower space by the barrier layer. The upper space is filled with a polymer explosion-proof material. A plurality of through holes are formed on the barrier layer. The tank body also includes a cleaning solution filling port and a liquid extraction port. The cleaning solution filling port is arranged on the circumferential side wall or the top of the lower space, and the liquid extraction port is arranged on the bottom wall of the lower space or the bottom of the circumferential side wall; the outlet of the water tank is connected to the cleaning solution filling port through the first pump, and the liquid extraction port is sequentially connected to the water return port of the water tank through the filter and the second pump.

[0020] Chinese Utility Model Patent, Publication No.: CN 202984223 U, Invention Title: Vehicle-mounted Mobile Oil Tank Cleaning Device, which is a vehicle-mounted mobile oil tank cleaning device, and its composition includes: a mobile trailer with a carriage, the carriage is equipped with an integrated fresh water tank and a sewage tank, the fresh water tank is connected to a cleaning pump, the cleaning pump is connected to a tank washer, the sewage tank is connected to a mobile sewage pump, and both the sewage tank and the fresh water tank are connected to an oil-water separator.

[0021] Chinese Utility Model Patent, Publication No.: CN 215103048 U, Invention Title: A Ferrous Sulfide Passivation Operation Device for Large-diameter Towers, includes a fixed plate body, on the upper surface of the fixed plate body, a passivation agent mixing tank and a waste liquid recovery tank are fixed, the passivation agent mixing tank is provided with a passivation agent stock solution tank and a water inlet pipe connected to its upper end, a water pump is arranged on the upper surface of the passivation agent mixing tank, and a drain pipe connected to the upper feed port of the tower body is arranged at the water delivery end of the water pump.

[0022] Chinese Utility Model Patent, Publication No.: CN 216024185 U, Invention Title: A Liquid Mixing Tank, includes a skid-mounted base and a tank body, a PLC control cabinet and a pressurizing pump arranged on the skid-mounted base, a rotating spraying device is arranged in the tank body, the rotating spraying device is connected to the tank body through a lifting device, the feed end and the discharge end of the pressurizing pump are respectively connected with a discharge pipe and a circulation pipe, the discharge pipe is communicated with the tank body, and the circulation pipe is in pipeline communication with the rotating spraying device.

[0023] Chinese Utility Model Patent, Publication No.: CN 212143812 U, Invention Title: An Oil Tank Cleaning System, a cleaning device, which includes a booster pump and a cleaning nozzle, the cleaning nozzle can be inserted into the oil tank and can be lifted and rotated 360° relative to the oil tank to spray and clean the inner wall of the oil tank.

[0024] The main features of the cleaning devices listed in the above patents are vehicle-mounted and manual cleaning devices, and there is no online iron ion detection function and no automatic on-site judgment of whether the passivation cleaning is qualified according to the pH value, temperature, and iron ion content. Manual sampling and analysis need to be carried out regularly, which is time-consuming and laborious. Summary of the Invention

[0025] In order to solve the problems of inaccurate manual ratio control of industrial water and passivation agent liquid, too long time-consuming of manual cleaning equipment, inability to analyze iron ion content and pH value online, inability to judge whether the passivation cleaning is qualified on-site, and large investment in manual labor, the present invention provides a method for cleaning ferrous sulfide based on a ferrous sulfide cleaning device.

[0026] To achieve the above object, the technical solution of the present application is a method for cleaning ferrous sulfide based on a ferrous sulfide cleaning device, including four stages: operation preparation stage, liquid supply stage, circulation stage, and shutdown stage. The specific steps are as follows:

[0027] Step 1, operation preparation stage: Check the valve status and whether the air supply is normal before operation; connect the power supply; start the ferrous sulfide cleaning device; set parameters in the PLC control system of the ferrous sulfide cleaning device;

[0028] Step 2, liquid supply stage: Open the vent solenoid valve, start the pneumatic diaphragm pump, and wait until the liquid level in the buffer tank reaches the set value. Then open the pneumatic regulating ball valve, the first pneumatic V-ball valve, and the electric pump A. The PLC control system injects industrial water and passivating agent liquid into the dissolution tank according to a given ratio. The air in the dissolution tank is discharged through the vent pipe. According to the liquid level height of the magnetic flap level gauge A, open or close the pneumatic diaphragm pump;

[0029] Step 3, circulation stage: When the magnetic flap level gauge B in the dissolution tank reaches the set liquid level, open the electric pump B and the second pneumatic V-ball valve (25). The opening degree of the second pneumatic V-ball valve is adjusted and controlled according to the liquid level signal measured by the magnetic flap level gauge B and fed back to the PLC control system;

[0030] When the liquid level of the magnetic flap level gauge B reaches 80% of the set liquid level, the second pneumatic V-ball valve is fully opened, and the electric pump B continuously supplies liquid to the inside of the equipment to be cleaned until the PLC control system prompts that the cumulative flow reaches the set value. The cumulative flow = the cumulative flow of electromagnetic flowmeter A + the cumulative flow of electromagnetic flowmeter B. Close the pneumatic regulating ball valve, the first pneumatic V-ball valve, and the electric pump A. After closing the vent solenoid valve, enter the circulation stage;

[0031] While the electric pump B supplies liquid to the inside of the equipment to be cleaned, the solution at the bottom of the equipment to be cleaned flows back to the dissolution tank, and the solution circulates in and out of the equipment to be cleaned. After the circulation runs stably for a certain period of time, the PLC control system automatically controls the first pneumatic V-ball valve and the electric pump A according to the numerical change of the PH detector to supplement a certain amount of passivating agent liquid into the system;

[0032] The PLC control system automatically judges whether the cleaning is completed according to the parameter change of the iron ion on-line monitor;

[0033] Step 4, shutdown stage: Check whether the industrial water valve outside the box body is closed, and check whether the electric pump B and the second pneumatic V-ball valve are closed. After confirmation, carry out the discharge operation; open the blowdown valve to discharge the waste liquid back to the waste water tank; finally, turn off the main power supply.

[0034] Further, the specific steps of Step 1 are as follows: Check whether the sewage valve is closed; check whether the air compressor outside the box supplies air; check whether the industrial water supply valve connected to the water inlet pipe outside the box is open; check whether all the wafer check valves before and after Filter A can be normally opened; secondly, make the power connection; finally, start the PLC control system of the ferrous sulfide cleaning device for parameter setting, and select the corresponding cleaning and passivation plan according to different equipment.

[0035] Further, in Step 2, the pneumatic regulating ball valve can be automatically adjusted according to the numerical signal displayed by Electromagnetic Flowmeter A until the numerical value displayed by Electromagnetic Flowmeter A is the set value. The first pneumatic V-ball valve is automatically adjusted according to the numerical signal displayed by Electromagnetic Flowmeter B until the numerical value displayed by Electromagnetic Flowmeter B is the set value. At this time, the PLC control system injects industrial water and passivating agent liquid into the dissolution tank according to the given ratio.

[0036] Further, the ratio at which the PLC control system injects industrial water and passivating agent liquid into the dissolution tank in Step 2 is specifically based on the formula: Y = KX + B; where X is the cumulative flow of the passivating agent cleaning liquid measured by Electromagnetic Flowmeter B, Y is the cumulative flow of industrial water measured by Electromagnetic Flowmeter A, and K and B are coefficients set in the PLC control system. The range of K is 8 - 12, and the range of B is -10 - 10.

[0037] Further, the criterion for the PLC control system to determine the end of cleaning in Step 3 is that when the cyclic cleaning lasts for 12 hours and the change in iron ion content in the most recent two hours does not exceed 10%, it automatically determines that the cleaning is over.

[0038] Further, in Step 3, when the magnetic flap level gauge B measures a level lower than 20%, the electric pump B is interlocked and closed; when the magnetic flap level gauge B measures a level higher than 80%, the electric pump A is interlocked and closed, the pneumatic regulating ball valve is interlocked and closed, and the first pneumatic V-ball valve is interlocked and closed.

[0039] The ferrous sulfide cleaning device used in the described invention cleaning method includes a dissolution tank, an iron ion on-line monitor, a pH detector, a distribution box, a passivator supply system, a water supply system, a circulating cleaning system, and a PLC control system inside the box; the dissolution tank is provided with a water inlet, and a safety valve and a vent solenoid valve are also installed at the top of the dissolution tank, a drain pipe is installed at the bottom of the dissolution tank, and a drain valve is provided on the drain pipe. The water supply system includes a water inlet pipe connected to the water inlet and a pneumatic regulating ball valve and an electromagnetic flowmeter A on the water inlet pipe; a magnetic flap level gauge B is provided on the side of the dissolution tank, and a ball valve D is installed between both ends of the magnetic flap level gauge B and the dissolution tank. A sampling valve, an instrument valve, and a pressure gauge are also installed on the dissolution tank; the passivator supply system includes an electric pump A, an electromagnetic flowmeter B, and a first pneumatic V-ball valve. The passivator supply system provides passivator liquid through a passivator solution barrel; on the pipeline between the passivator solution barrel and the dissolution tank, an electric pump A, an electromagnetic flowmeter B, and a first pneumatic V-ball valve are installed in sequence; the circulating cleaning system includes a ball valve C, an electric pump B, a second pneumatic V-ball valve, an integrated thermal resistor, and a filter A. On the circulating liquid outlet pipeline from the outlet end of the dissolution tank to the equipment to be cleaned, a ball valve C, an electric pump B, and a second pneumatic V-ball valve are installed in sequence; on the circulating liquid outlet pipeline from the equipment to be cleaned to the inlet end of the dissolution tank, an integrated thermal resistor and a filter A are installed in sequence; the pH detectors are respectively installed at the inlet end and the outlet end of the dissolution tank, and the iron ion on-line monitor is installed on the circulating liquid outlet pipeline between the inlet end of the dissolution tank and the pH detector. The described PLC control system is electrically connected to the electromagnetic flowmeter A, the electromagnetic flowmeter B, the iron ion on-line monitor, the pH detector, the integrated thermal resistor, the magnetic flap level gauge A, the magnetic flap level gauge B, the first solenoid valve, and the vent solenoid valve through signal lines. The electromagnetic flowmeter B and the electric pump A are also electrically connected through signal lines. The pneumatic regulating ball valve and the electromagnetic flowmeter A are electrically connected through signal lines. The magnetic flap level gauge A and the first solenoid valve are electrically connected through signal lines. The magnetic flap level gauge B and the second pneumatic V-ball valve are electrically connected through signal lines. The second pneumatic V-ball valve automatically adjusts the opening degree according to the signal of the magnetic flap level gauge B under the control of the PLC control system.

[0040] Further, on the pipeline between the passivator solution barrel and the electric pump A, a pneumatic diaphragm pump, a buffer tank, and a ball valve A are also provided. A breather valve and a breathing port are provided at the top of the buffer tank, a magnetic flap level gauge A is also installed on the side of the buffer tank, a ball valve B is also provided between both ends of the magnetic flap level gauge A and the buffer tank, and a first solenoid valve is also provided between the pneumatic diaphragm pump and the magnetic flap level gauge A.

[0041] Further, a ball valve E is also provided at the bottom of the buffer tank.

[0042] Further, a check valve A is also installed on the pipeline between the first pneumatic V-ball valve and the dissolution tank.

[0043] Further, the circulating cleaning system further includes a reflux pipeline. One end of the reflux pipeline is connected to the dissolution tank, and the other end is connected between the electric pump B and the second pneumatic V-ball valve. A wafer check valve is also installed on the reflux pipeline.

[0044] Further, a check valve B is also provided on the circulating liquid outlet pipeline between the equipment to be cleaned and the second pneumatic V-ball valve.

[0045] Further, a sampling valve is also installed on the circulating liquid outlet pipeline between the iron ion on-line monitor and the PH detector.

[0046] Further, filter A and filter B are in parallel, and wafer check valves are also installed at both ends of filter A and filter B.

[0047] Further, a glass window is also provided on the circulating liquid outlet pipeline between the integrated thermal resistor and the equipment to be cleaned. The glass window is located outside the box and is used to directly observe the liquid in the pipeline.

[0048] Further, instrument valves and pressure gauges are provided on the pipeline between the electromagnetic flowmeter B and the electric pump A and on the circulating liquid outlet pipeline between the electric pump B and the second pneumatic V-ball valve.

[0049] The present invention adopts the above technical solutions and can achieve the following technical effects:

[0050] (1) Compared with the existing method of sampling and sending the passivator cleaning liquid out for laboratory analysis of its indicators, through the PLC control system, the iron ion on-line monitor and the PH detector, the iron ion content can be monitored in real time on-line and the pH value can be monitored on-line. According to the parameter changes, the degree of reaction between the passivator liquid and ferrous sulfide can be automatically judged on-line, and whether the cleaning is qualified can be judged, so as to achieve the purpose of automatically detecting the cleaning effect.

[0051] (2) The present invention performs automated operations and precise control of the ratio of industrial water to passivator liquid through the PLC control system, greatly improving the cleaning efficiency, reducing both the errors in manual operations and saving a large amount of time.

[0052] (3) Compared with the existing methods of manually preparing the passivator cleaning liquid, monitoring the cleaning process, regularly sampling the circulating cleaning liquid and sending it to the laboratory for testing, etc., the present invention greatly reduces the manpower requirement through an automated operation process and real-time on-line monitoring, thus saving labor costs. In addition, a sealed dissolution tank is used for the circulation of the passivator cleaning liquid, reducing the contact between the passivator cleaning liquid and the outdoor air, avoiding the harm to on-site cleaning personnel from inhaling sulfur-containing gases and reducing air pollution. Description of the Drawings

[0053] Figure 1This is a schematic structural diagram of the cleaning device for ferrous sulfide according to the present invention;

[0054] Figure 2 This is a top view schematic diagram of the cleaning device for ferrous sulfide according to the present invention;

[0055] Figure 3 This is a front view schematic diagram of the cleaning device for ferrous sulfide according to the present invention;

[0056] Figure 4 This is a schematic diagram of the cleaning process for the reflux drum of the stripping column T5101 according to the present invention;

[0057] Figure 5 This is a schematic diagram of the cleaning process for the debutanizer and the overhead reflux drum T1101 / V1108 system according to the present invention.

[0058] Explanation of the numbers in the figure: 1. Pneumatic regulating ball valve; 2. Electromagnetic flowmeter A; 3. Safety valve; 4. Online iron ion monitor; 5. PH detector; 6. Wafer check valve; 7. Filter A; 8. Sampling valve; 9. Integrated thermal resistor; 10. Check valve A; 11. First pneumatic V-ball valve; 12. Electromagnetic flowmeter B; 13. Instrument valve; 14. Pressure gauge; 15. Electric pump A; 16. Ball valve A; 17. Buffer tank; 18. Ball valve B; 19. Magnetic flap level gauge A; 20. Pneumatic diaphragm pump; 21. Dissolving tank; 22. Drain valve; 23. Ball valve C; 24. Electric pump B; 25. Second pneumatic V-ball valve; 26. Check valve B; 27. Wafer ball valve; 28. First solenoid valve; 29. Glass window; 30. Equipment to be cleaned; 31. Passivator solution tank; 32. Box body; 34. Vent pipe; 35. Vent solenoid valve; 36. Breather port; 37. Breather valve; 38. Signal line; 39. PLC control system; 40. Ball valve E; 41. Water inlet pipe; 42. Drain pipe; 43. Circulating liquid outlet pipeline; 44. Return pipeline; 46. Distribution box; 47. Filter B; 49. Magnetic flap level gauge B; 50. Ball valve D. Detailed implementation manners

[0059] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments: This is taken as an example to further describe and explain the present application.

[0060] Embodiment 1:

[0061] As Figures 1 - 3 shown, this embodiment provides a method for cleaning ferrous sulfide based on the cleaning device for ferrous sulfide, and the cleaning includes four stages: preparation stage, liquid supply stage, circulation stage, and shutdown stage.

[0062] The preparation stage is the pre - operation inspection: First, check whether the blow - off valve 22 is closed; check whether the air compressor outside the box body 32 supplies air; check whether the industrial water supply valve connected to the water inlet pipe 41 outside the box body 32 is open; check whether all the wafer - type butterfly valves 6 before and after the filter A7 can be normally opened. Secondly, make the power connection to ensure it is firmly fastened. Finally, start the PLC control system 39 for parameter setting, and select the corresponding cleaning and passivation scheme according to different equipment. During the cleaning and passivation process, it is allowed to adjust the concentration, temperature and flow rate of the passivation agent cleaning solution within a certain range. As the usage time of the passivation agent cleaning solution increases, the concentration of the liquid and the concentration of iron ions will change.

[0063] In the liquid supply stage, specifically, check whether the vent solenoid valve 35 is open to ensure that the inspection of the vent solenoid valve 35 is correct; then start the pneumatic diaphragm pump 20. After waiting for the liquid level in the buffer tank 17 to reach the set value, open the pneumatic control ball valve 1, the first pneumatic V - type ball valve 11, and the electric pump A15. The pneumatic control ball valve 1 can be automatically adjusted according to the numerical signal displayed by the electromagnetic flowmeter A2 until the numerical value displayed by the electromagnetic flowmeter A2 is the set value. The first pneumatic V - type ball valve 11 is automatically adjusted according to the numerical signal displayed by the electromagnetic flowmeter B12 until the numerical value displayed by the electromagnetic flowmeter B12 is the set value. At this time, the PLC control system 39 injects industrial water and passivation agent liquid into the dissolution tank 21 according to a given ratio. Specifically, according to the formula: Y = KX + B; where X is the flow rate measured by the electromagnetic flowmeter B12 (cumulative flow rate of the passivation agent cleaning solution), Y is the flow rate measured by the electromagnetic flowmeter A2 (cumulative flow rate of industrial water), and K and B are coefficients set in the PLC control system 39 by itself. (The range of K is 8 - 12, and the range of B is - 10 - 10). The air in the dissolution tank 21 is discharged through the vent pipe 34. When the magnetic flap level gauge A19 measures a 20% interlock of the liquid level, open the pneumatic diaphragm pump 20; when the magnetic flap level gauge A19 measures an 80% interlock of the liquid level, close the pneumatic diaphragm pump 20.

[0064] Circulation stage:

[0065] When the magnetic flap level gauge B49 of the dissolution tank 21 reaches the set liquid level, usually the set liquid level is set to be equal to 75% of the volume of the equipment to be cleaned 30, the electric pump B24 is opened, and the second pneumatic V - type ball valve 25 is opened. The opening degree of the second pneumatic V - type ball valve 25 is regulated and controlled according to the liquid level signal measured by the magnetic flap level gauge B49 and fed back to the PLC control system 39. When the liquid level is greater than 60% and less than 80%, increase the opening degree of the second pneumatic V - type ball valve 25; when the liquid level is greater than 20% and less than 60%, decrease the opening degree of the second pneumatic V - type ball valve 25.

[0066] When the level of the magnetic flap level gauge B49 in the dissolution tank 21 reaches 80% of the set level, the second pneumatic V-ball valve 25 is fully opened, and the electric pump B24 continuously supplies liquid into the equipment 30 to be cleaned until the PLC control system 39 prompts that the cumulative flow reaches the set value. The cumulative flow = the cumulative flow of the electromagnetic flowmeter A2 + the cumulative flow of the electromagnetic flowmeter B12. The pneumatic regulating ball valve 1 is closed, the first pneumatic V-ball valve 11 is closed, and the electric pump A15 is closed (or manually enter the circulation stage). At this time, the PLC control system 39 will prompt to close the vent solenoid valve 35. After closing the vent solenoid valve 35, enter the circulation stage; when the magnetic flap level gauge B49 in the dissolution tank 21 measures a level lower than 20%, the electric pump B24 is interlocked and closed; when the magnetic flap level gauge B49 in the dissolution tank 21 measures a level higher than 80%, the electric pump A15 is interlocked and closed, the pneumatic regulating ball valve 1 is interlocked and closed, and the first pneumatic V-ball valve 11 is interlocked and closed.

[0067] While the electric pump B24 supplies liquid into the equipment 30 to be cleaned, the solution at the bottom of the equipment 30 to be cleaned flows back into the dissolution tank 21, and the solution circulates in and out of the equipment 30 to be cleaned; after the circulation runs stably for a certain period of time, the PLC control system 39 automatically controls the first pneumatic V-ball valve 11 and the electric pump A15 according to the change of the value of the PH detector 5 to supplement a certain amount of passivating agent liquid into the system.

[0068] The PLC control system 39 automatically judges that the cleaning is completed according to the change of the parameters of the iron ion on-line monitor 4 detected. When the iron ion content does not change by more than 10% in the most recent two hours after 12 hours of circulating cleaning.

[0069] Shutdown stage:

[0070] Check whether the industrial water valve outside the box body 32 is closed, check whether the electric pump B24 and the second pneumatic V-ball valve 25 are closed. After confirmation, carry out the discharge operation; open the drain valve 22 to drain the waste liquid back to the waste water tank; finally, turn off the main power supply.

[0071] The ferrous sulfide cleaning device used in the present cleaning method includes a dissolution tank 21, an iron ion on-line monitor 4, a PH detector 5, a distribution box 46, a passivating agent supply system, a water supply system, a circulating cleaning system, and a PLC control system 39 in the box body 32; among them, the iron ion on-line monitor 4 is used to monitor the iron ion content in the passivating agent cleaning solution in real time; the PH detector 5 is used to monitor the PH value of the passivating agent cleaning solution in real time, the passivating agent supply system is used to inject the passivating agent liquid into the dissolution tank 21; the water supply system is used to inject industrial water into the dissolution tank 21; the circulating cleaning system is used to clean the equipment 30 to be cleaned; the PLC control system 39 is used to accurately control the automatic proportioning and injection of industrial water and passivating agent liquid, and automatically judge whether the passivating cleaning is qualified, and the distribution box 46 is used to supply power to each electrical load.

[0072] The described dissolving tank 21 is provided with a water inlet. A safety valve 3 and a vent solenoid valve 35 are also installed at the top of the dissolving tank 21. The opening and closing of the safety valve 3 and the vent solenoid valve 35 control the connection between the vent pipe 34 and the outside. A drain pipe 42 is installed at the bottom of the dissolving tank 21, and a drain valve 22 is provided on the drain pipe 42, facilitating the discharge of the medium in the dissolving tank 21 from the drain pipe 42 into the waste water tank. The water supply system includes a water inlet pipe 41 connected to the water inlet and a pneumatic regulating ball valve 1 and an electromagnetic flowmeter A2 on the water inlet pipe 41. The pneumatic regulating ball valve 1 and the electromagnetic flowmeter A2 are electrically connected through a signal line 38. The pneumatic regulating ball valve 1 automatically adjusts the opening degree according to the signal of the electromagnetic flowmeter A2 through the PLC control system 39. A magnetic flap level gauge B49 is provided on the side of the dissolving tank 21. A ball valve D50 is installed between both ends of the magnetic flap level gauge B49 and the dissolving tank 21. A sampling valve 8, an instrument valve 13 and a pressure gauge 14 are also installed on the dissolving tank 21. By setting the sampling valve 8, it is convenient for the operator to take samples and test the medium in the dissolving tank 21. The pressure gauge 14 is used to measure the pressure in the dissolving tank 21. When the pressure is too high, the safety valve 3 is opened for pressure relief. The described electromagnetic flowmeter A2 is used to collect flow values (industrial water flow value, industrial water cumulative flow value). The magnetic flap level gauge B49 is used to monitor the medium liquid level in the dissolving tank 21. When the liquid level is higher than 80% of the liquid level or lower than 20% of the liquid level, after the PLC control system 39 receives the signal, it starts the safety interlock and controls the opening degree of the second pneumatic V-ball valve 25.

[0073] The described passivating agent supply system includes an electric pump A15, an electromagnetic flowmeter B12, a first pneumatic V-ball valve 11, a check valve A10, a pneumatic diaphragm pump 20, a buffer tank 17 and a ball valve A16; the passivating agent supply system provides the source of the passivating agent liquid through the passivating agent solution tank 31;

[0074] The pneumatic diaphragm pump 20 is provided on the liquid supply pipeline at the outlet end of the passivator solution tank 31. The output end of the pneumatic diaphragm pump 20 is connected to the buffer tank 17 through the liquid supply pipeline. A ball valve A 16 is provided at the outlet end of the buffer tank 17. The other end of the ball valve A 16 is connected to the electric pump A 15 through a pipeline. The output end of the electric pump A 15 is connected to the electromagnetic flowmeter B 12. The electromagnetic flowmeter B 12 is connected to the first pneumatic V-ball valve 11. The first pneumatic V-ball valve 11 is connected to the check valve A 10 through a pipeline. The check valve A 10 is connected to the inlet end of the dissolution tank 21 through a pipeline. A breather valve 37 and a breathing port 36 are provided at the top of the buffer tank 17. The breather valve 37 and the breathing port 36 are used to discharge the passivator liquid in case of emergency. A ball valve E 40 is also provided at the bottom end of the buffer tank 17. The purpose of setting the ball valve E 40 is to drain the cleaning liquid in the pipeline and the buffer tank 17 after the cleaning is completed, prevent the pipeline from freezing, and avoid corrosion caused by the long-term retention of the passivator liquid. A magnetic flap level gauge A 19 is also installed on the side of the buffer tank 17. A ball valve B 18 is provided between both ends of the magnetic flap level gauge A 19 and the buffer tank 17. A first solenoid valve 28 is also provided between the pneumatic diaphragm pump 20 and the magnetic flap level gauge A 19. By setting the buffer tank 17 and the pneumatic diaphragm pump 20, the problem that when the passivator solution tank 31 needs to be replaced during the process of the electric pump A 15 sucking the passivator, some gas enters the pipeline and the electric pump A 15 cannot suck up the passivator is solved. An instrument valve 13 and a pressure gauge 14 are provided on the pipeline between the electromagnetic flowmeter B 12 and the electric pump A 15. The pressure gauge 14 is used to monitor the pressure of the passivator liquid supply pipeline. The electromagnetic flowmeter B 12 is used to collect flow values (passivator liquid flow value, passivator liquid cumulative flow value). The magnetic flap level gauge A 19 is used to monitor the level of the passivator liquid in the buffer tank 17. When the level is higher than 80% level or lower than 20% level, after the PLC control system 39 receives the signal, it starts the safety interlock and controls the first solenoid valve 28 for interlocking.

[0075] The described circulating cleaning system includes a ball valve C23, an electric pump B24, a second pneumatic V-ball valve 25, a check valve B26, an integrated thermal resistor 9, and a filter A7. The ball valve C is installed on the circulating liquid outlet pipeline 43 at the outlet end of the dissolution tank 21. The other end of the ball valve C23 is connected to the electric pump B24 through a pipeline. The output end of the electric pump B24 is connected to the second pneumatic V-ball valve 25 through the circulating liquid outlet pipeline 43. The other end of the second pneumatic V-ball valve 25 is connected to the check valve B26 through the circulating liquid outlet pipeline 43. The other end of the check valve B26 is connected to the inlet end of the equipment to be cleaned 30 through the circulating liquid outlet pipeline 43. An integrated thermal resistor 9 and a filter A7 are also successively installed on the circulating liquid outlet pipeline 43 at the outlet end of the equipment to be cleaned 30. A meter valve 13 and a pressure gauge 14 are provided on the circulating liquid outlet pipeline 43 between the electric pump B24 and the second pneumatic V-ball valve 25. The pressure gauge 14 is used to detect the pressure on the circulating pipeline. A glass window 29 is also provided on the circulating liquid outlet pipeline 43 between the outlet end of the equipment to be cleaned 30 and the integrated thermal resistor 9. The glass window 29 is a transparent pipeline and is used to directly observe the liquid in the pipeline. The filter A7 is in parallel with the filter B47. Opposed flange butterfly valves 6 are also installed at both ends of the filter A7 and the filter B47. By providing two parallel branches, it is convenient for replacement and maintenance without affecting the operation. For example, when the filter A7 is blocked, the opposed flange butterfly valves 6 at both ends of the filter A7 are closed and then the filter A7 is removed for maintenance. At the same time, the opposed flange butterfly valves 6 at both ends of the filter B47 are opened for operation.

[0076] Further, the circulating cleaning system also includes a return pipeline 44. One end of the return pipeline 44 is connected to the dissolution tank 21, and the other end is connected between the electric pump B24 and the second pneumatic V-ball valve 25. An opposed flange ball valve 27 is also installed on the return pipeline 44. The purpose of setting the return pipeline 44 and the opposed flange ball valve 27 is to adjust the outlet flow of the electric pump B24 on the main pipeline and also to have a stirring effect on the dissolution tank 21 after reflux, which is conducive to the full mixing of the passivating agent liquid and industrial water.

[0077] One pH detector 5 is installed between the sampling valve 8 and the opposed flange butterfly valve 6 at the inlet end of the dissolution tank 21, and the other pH detector 5 is installed between the ball valve C23 and the electric pump B24 at the outlet end of the dissolution tank 21. The iron ion on-line monitor 4 is installed on the circulating liquid outlet pipeline 43 between the inlet end of the dissolution tank 21 and the pH detector 5.

[0078] The described PLC control system 39 (PLC programmable controller) is electrically connected to the electromagnetic flowmeter A2, electromagnetic flowmeter B12, iron ion on-line monitor 4, PH detector 5, integrated thermal resistor, magnetic flap level gauge A19, magnetic flap level gauge B49, first solenoid valve 28 and vent solenoid valve 35 through signal line 38, and can collect signals, store data and control the operation of each component. The PLC control system 39 has a historical data query function, and can view the historical data curves of ferrous sulfide content, PH value, temperature, liquid level, industrial water flow rate, passivator liquid flow rate, total flow rate (industrial water flow rate + passivator liquid flow rate) by time period. It also has safety interlock and alarm functions. The electromagnetic flowmeter B12 and the electric pump A15 are also electrically connected through the signal line 38, and the electric pump A15 can automatically adjust the opening degree according to the signal of the electromagnetic flowmeter B12 through the PLC control system 39; the magnetic flap level gauge A19 and the first solenoid valve 28 are electrically connected through the signal line 38, and the magnetic flap level gauge B49 and the second pneumatic V-ball valve 25 are electrically connected through the signal line 38, and both are controlled by the PLC control system 39 to operate. The sampling valve 8 of the dissolution tank 21 and the circulating cleaning system is used for manual sampling and then sending it to the laboratory for chemical analysis and detection of various parameter indicators of the passivator cleaning solution.

[0079] The water supply system injects industrial water into the dissolution tank 21, and the passivator liquid supply system injects passivator liquid into the dissolution tank 21. After the passivator liquid and industrial water fully react, a passivator cleaning solution is formed. The passivator cleaning solution flows out of the dissolution tank 21 and is pumped by the electric pump B24 to the equipment to be cleaned 30 for cleaning, and then flows back to the dissolution tank 21. During the liquid supply stage, the electromagnetic flowmeter A2 collects the industrial water flow rate value and the industrial water cumulative flow rate value, and the electromagnetic flowmeter B12 collects the passivator liquid flow rate value and the passivator liquid cumulative flow rate value. Through the PLC control system 39, the passivator liquid and industrial water are mixed in a set ratio; during the circulating cleaning stage, the iron ion on-line monitor 4 collects the iron ion content, and judges the reaction degree of the passivator cleaning solution and ferrous sulfide through the change of the iron ion content; the PH detector 5 can collect the PH value, and the integrated thermal resistor collects the temperature. The PLC control system 39 judges the reaction degree of the passivator liquid and ferrous sulfide through the collected iron ion content, PH value and temperature data, judges whether the cleaning is qualified, and thus gives corresponding control instructions, ultimately achieving the purpose of automatically detecting the cleaning effect. Among them, the average value is calculated by collecting two PH values at the inlet end and the outlet end of the dissolution tank 21 for comprehensive judgment.

[0080] In this embodiment, as Figure 4 shown, the reflux tank of the stripping column T5101 is cleaned;

[0081] At 20:00 on March 31st, 8 tons of passivator were added according to the set ratio (Y = KX + B, K = 10, B = 0), and the total soaking time was 7 hours. At 6:00 on April 1st, the reflux drum of the stripping column T5101 was circulated. At 8:30, the pH value showed an obvious downward trend, dropping from 7.3 to 6.07. At 11:00, a total of 2 tons of passivator were automatically added; the pH value before adding the agent was 6.07, and the pH value was 6.54 half an hour after the addition of the passivator ended. At 16:00, the pH value was 7.70. On April 2nd, the passivation cleaning ended at 10:00. During the cleaning process, the iron ion content of the circulating cleaning solution was monitored online, and the analysis results are shown in Table 1:

[0082] Table 1: Changes in iron ion content and pH value

[0083] Online monitoring time pH value Iron ion content, ug / ml April 1st (6:30) 6.34 196.20 April 1st (8:30) 7.30 128.10 April 1st (9:00) 6.07 145.26 April 1st (11:00) 6.67 100.97 April 1st (11:30) 6.52 110.21 April 1st (14:00) 7.51 64.09 April 1st (16:00) 7.70 43.06 April 1st (21:00) 7.28 22.31 April 1st (22:00) 7.24 21.22

[0084] As can be seen from Table 1 above, the iron ion content in the initial stage of the stripping column T5101 system was relatively high, indicating that the cleaning reaction in the system was relatively intense in the initial stage of adding the passivator. In the middle stage, since the cleaning effect was not achieved, 2 tons of passivator were automatically supplemented. In the later stage of the cleaning process, as the detected iron ion content tended to be stable and the change in iron ion content within two hours did not exceed 10%, it was automatically judged that the passivation cleaning was completed. Using the present invention saves more than half of the planned cleaning time and 2 tons of the planned passivator dosage. Only 2 employees are required to complete the operation on site.

[0085] As Figure 5 shown, this embodiment also cleans the debutanizer and the top reflux drum T1101 / V1108 system:

[0086] On May 11th, the passivation cleaning was carried out using the cleaning device. At 17:00, industrial water and passivator were added to the debutanizer T1101 system according to the set ratio (Y = KX + B, K = 9, B = -5). At 20:00, a total of 9 tons of passivator were added to the system, and the total soaking time was 10 hours. At 6:30 on May 12th, the system started circulating cleaning. At 14:00 on May 12th, the cleaning device showed that the pH value of the system return water was 7.73 and the circulating water temperature was 27°C. The system was kept circulating until 23:00 on May 12th. During the cleaning process, the iron ion content and pH value of the cleaning solution were monitored, and the analysis results are shown in Table 2. It can be seen from this that the iron ion content in the initial stage of the debutanizer T1101 system was unstable. As the detected iron ion content tended to be stable and the change in iron ion content within two hours did not exceed 10%, it was automatically judged that the passivation cleaning was completed.

[0087] Table 2: Changes in iron ion content and pH value

[0088] Online monitoring time pH value Iron ion content, ug / ml May 12th (6:30) 6.8 225.46 May 12th (10:00) 7.03 143.96 May 12th (12:00) 7.32 122.87 May 12th (14:00) 7.73 84.64 May 12th (16:00) 7.5 35.32 May 12th (21:00) 7.4 22.83 May 12th (22:00) 7.43 21.26 May 12th (23:00) 7.42 20.57

[0089] The above are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, making equivalent substitutions or changes should be covered within the protection scope of the present invention.

Claims

1. A method for cleaning ferrous sulfide based on a ferrous sulfide cleaning device, comprising four stages: operation preparation stage, liquid supply stage, circulation stage, and shutdown stage, characterized in that, The specific steps are as follows: Step 1: Preparation stage before operation: Check the valve status and the normal supply of gas before operation; Connect the power supply; Start the power button of the ferrous sulfide cleaning device; Set parameters for the PLC control system (39) of the ferrous sulfide cleaning device; Step 2: Liquid supply stage: Open the vent solenoid valve (35), start the pneumatic diaphragm pump (20), and wait until the liquid level in the buffer tank (17) reaches the set value. Then open the pneumatic control ball valve (1), the first pneumatic V-ball valve (11), and the electric pump A (15). The PLC control system (39) injects industrial water and passivating agent liquid into the dissolution tank (21) according to a given ratio. The air in the dissolution tank (21) is discharged through the vent pipe (34). According to the liquid level height of the magnetic flap level gauge A (19), open or close the pneumatic diaphragm pump (20); Step 3: Circulation stage: When the magnetic flap level gauge B (49) in the dissolution tank (21) reaches the set liquid level, open the electric pump B (24) and the second pneumatic V-ball valve (25). The opening degree of the second pneumatic V-ball valve (25) is adjusted and controlled according to the liquid level signal measured by the magnetic flap level gauge B (49) and fed back to the PLC control system (39); When the liquid level of the magnetic flap level gauge B (49) reaches the set high liquid level, the second pneumatic V-ball valve (25) is fully opened, and the electric pump B (24) continuously supplies liquid to the interior of the equipment to be cleaned (30) until the PLC control system (39) prompts that the cumulative flow reaches the set value. The cumulative flow = the cumulative flow of the electromagnetic flowmeter A (2) + the cumulative flow of the electromagnetic flowmeter B (12). Close the pneumatic control ball valve (1), the first pneumatic V-ball valve (11), and the electric pump A (15). After closing the vent solenoid valve (35), enter the circulation stage; While the electric pump B (24) supplies liquid to the interior of the equipment to be cleaned (30), the solution at the bottom of the equipment to be cleaned (30) flows back into the dissolution tank (21), and the solution circulates in and out of the equipment to be cleaned (30). After the circulation operates stably for a certain period of time, the PLC control system (39) automatically controls the first pneumatic V-ball valve (11) and the electric pump A (15) according to the change in the value of the PH detector (5) to supplement a certain amount of passivating agent liquid into the system; The PLC control system (39) automatically determines whether the cleaning is completed according to the parameter changes received by the iron ion on-line monitor (4); Step 4: Shutdown stage: Check whether the industrial water valve outside the box body (32) is closed, and check whether the electric pump B (24) and the second pneumatic V-ball valve (25) are closed. After confirmation, perform the discharge operation; Open the drain valve (22) to drain the waste liquid back to the waste water tank; Finally, turn off the main power supply.

2. The method for cleaning ferrous sulfide based on a ferrous sulfide cleaning device according to claim 1, characterized in that, Specifically, Step 1 is to check whether the drain valve (22) is closed; Check whether the air compressor outside the box body (32) supplies gas; Check whether the industrial water supply valve connected to the water inlet pipe (41) outside the box body (32) is opened; Check whether all the wafer-type butterfly valves (6) before and after the filter A (7) can be normally opened; Secondly, make the power connection; finally, start the PLC control system (39) of the ferrous sulfide cleaning device to set parameters, and select the corresponding cleaning and passivation plan according to different equipment.

3. The method for cleaning ferrous sulfide based on a ferrous sulfide cleaning device according to claim 1, characterized in that, In Step 2, the pneumatic control ball valve (1) can be automatically adjusted according to the numerical signal displayed by the electromagnetic flowmeter A (2) until the numerical value displayed by the electromagnetic flowmeter A (2) reaches the set value. The first pneumatic V-ball valve (11) is automatically adjusted according to the numerical signal displayed by the electromagnetic flowmeter B (12) until the numerical value displayed by the electromagnetic flowmeter B (12) reaches the set value. At this time, the PLC control system (39) injects industrial water and passivating agent liquid into the dissolution tank (21) according to a given ratio.

4. The method for cleaning ferrous sulfide based on a ferrous sulfide cleaning device according to claim 1, characterized in that, In Step 2, the ratio at which the PLC control system (39) injects industrial water and passivating agent liquid into the dissolution tank (21) is specifically based on the formula: Y = KX + B; where X is the cumulative flow of the passivating agent cleaning liquid measured by the electromagnetic flowmeter B (12), Y is the cumulative flow of industrial water measured by the electromagnetic flowmeter A (2), and K and B are coefficients set by the PLC control system (39) itself. The range of K is 8 - 12, and the range of B is -10 - 10.

5. The method for cleaning ferrous sulfide based on a ferrous sulfide cleaning device according to claim 1, characterized in that, In Step 3, the criterion for the PLC control system (39) to determine the end of cleaning is that when the cyclic cleaning has been carried out for 12 hours and the change in iron ion content in the most recent two hours does not exceed 10%, it automatically determines that the cleaning is over.

6. The method for cleaning ferrous sulfide based on a ferrous sulfide cleaning device according to claim 1, characterized in that, In Step 3, when the magnetic flap level gauge B (49) measures a level lower than the low level, the electric pump B (24) is interlocked and closed; when the magnetic flap level gauge B (49) measures a level higher than the high level, the electric pump A (15) is interlocked and closed, the pneumatic control ball valve (1) is interlocked and closed, and the first pneumatic V-ball valve (11) is interlocked and closed.

7. The method for cleaning ferrous sulfide based on a ferrous sulfide cleaning device according to claim 1, characterized in that, Ferrous sulfide cleaning device, including a dissolution tank (21) inside a box body (32), an iron ion on-line monitor (4), a pH detector (5), a distribution box (46), a passivator feeding system, a water supply system, a circulating cleaning system, and a PLC control system (39); the dissolution tank (21) is provided with a water inlet, and a safety valve (3) and a vent solenoid valve (35) are further installed at the top of the dissolution tank (21), and a drain valve (22) is installed at the bottom of the dissolution tank (21). The water supply system includes a water inlet pipe (41) connected to the water inlet and a pneumatic regulating ball valve (1) and an electromagnetic flowmeter A (2) on the water inlet pipe (41); a magnetic flap level gauge B (49) is provided on the side of the dissolution tank (21), and a ball valve D (50) is installed between both ends of the magnetic flap level gauge B (49) and the dissolution tank (21); the passivator feeding system includes an electric pump A (15), an electromagnetic flowmeter B (12), and a first pneumatic V-type ball valve (11), and the passivator feeding system is provided with a source of passivator liquid through a passivator solution barrel (31); an electric pump A (15), an electromagnetic flowmeter B (12), and a first pneumatic V-type ball valve (11) are sequentially installed on the pipeline between the passivator solution barrel (31) and the dissolution tank (21); the circulating cleaning system includes a ball valve C (23), an electric pump B (24), a second pneumatic V-type ball valve (25), an integrated thermal resistor (9), and a filter A (7). A circulating liquid outlet pipeline (43) is sequentially installed with a ball valve C (23), an electric pump B (24), and a second pneumatic V-type ball valve (25) from the outlet end of the dissolution tank (21) to the equipment to be cleaned (30); an integrated thermal resistor (9) and a filter A (7) are sequentially installed on the circulating liquid outlet pipeline (43) from the equipment to be cleaned (30) to the inlet end of the dissolution tank (21); the pH detector (5) is respectively installed at the inlet end and the outlet end of the dissolution tank (21), and the iron ion on-line monitor (4) is installed on the circulating liquid outlet pipeline (43) between the inlet end of the dissolution tank (21) and the pH detector (5). The PLC control system (39) is electrically connected to the electromagnetic flowmeter A (2), the electromagnetic flowmeter B (12), the iron ion on-line monitor (4), the pH detector (5), the integrated thermal resistor (9), the magnetic flap level gauge A (19), the magnetic flap level gauge B (49), the first solenoid valve (28), and the vent solenoid valve (35) through a signal line (38). The electromagnetic flowmeter B (12) and the electric pump A (15) are also electrically connected through a signal line (38). The pneumatic regulating ball valve (1) and the electromagnetic flowmeter A (2) are electrically connected through a signal line (38). The magnetic flap level gauge A (19) and the first solenoid valve (28) are electrically connected through a signal line (38). The magnetic flap level gauge B (49) and the second pneumatic V-type ball valve (25) are electrically connected through a signal line (38).

8. The method for cleaning ferrous sulfide based on a ferrous sulfide cleaning device according to claim 7, characterized in that, A pneumatic diaphragm pump (20), a buffer tank (17) and a ball valve A (16) are also provided on the pipeline between the passivator solution tank (31) and the electric pump A (15). A breather valve (37) and a breathing port (36) are provided at the top of the buffer tank (17). A magnetic flap level gauge A (19) is also installed on the side of the buffer tank (17). A ball valve B (18) is also provided between both ends of the magnetic flap level gauge A (19) and the buffer tank (17). A first solenoid valve (28) is also provided between the pneumatic diaphragm pump (20) and the magnetic flap level gauge A (19).

9. The method for cleaning ferrous sulfide based on a ferrous sulfide cleaning device according to claim 7, characterized in that, The circulating cleaning system further includes a reflux pipeline (44). One end of the reflux pipeline (44) communicates with the dissolution tank (21), and the other end communicates with the circulating liquid outlet pipeline (43) between the electric pump B (24) and the second pneumatic V-ball valve (25). A wafer check valve (27) is also installed on the reflux pipeline.

10. The method for cleaning ferrous sulfide based on a ferrous sulfide cleaning device according to claim 7, characterized in that, The filter A (7) is in parallel with the filter B (47). Wafer check valves (6) are also installed at both ends of the filter A (7) and the filter B (47).

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