Device for cleaning waste acid pipeline of silicon steel unit

Abstract

The invention discloses a device for cleaning a waste acid pipeline of a silicon steel unit, and belongs to the field of cold-rolled silicon steel production. The device comprises a 10m < 3 > steel lining rubber alkali liquor circulation tank, and the 10m < 3 > steel lining rubber alkali liquor circulation tank is provided with the following structures: a polytetrafluoroethylene coated graphite nylon acid-resistant pipe is mounted in the 10m < 3 > steel lining rubber alkali liquor circulation tank, and steam is introduced to heat alkali liquor; a guided wave type radar liquid level meter is arranged at the top of the 10m < 3 > steel lining rubber alkali liquor circulating tank and is used for monitoring the liquid level height in the tank; a steam inlet and outlet pipeline joint is arranged at the top of the 10m < 3 > steel lining rubber alkali liquor circulating tank, a steam inlet pipeline is connected with a wide net steam pipeline, a pneumatic control valve is arranged on the pipeline, and an outlet pipeline is discharged to a trench. By means of the device, online cleaning operation on the waste acid pipeline of the silicon steel unit can be achieved, the acid pickling speed and the acid pickling quality of silicon steel products are guaranteed while waste acid discharge in an acid tank of the unit is guaranteed, and cutting cleaning operation of the waste acid pipeline is avoided due to circulating cleaning operation of the waste acid pipeline.

Description

Technical Field

[0001] This invention relates to the production of cold-rolled silicon steel, and more particularly to an apparatus for cleaning waste acid pipelines of silicon steel production units. Background Technology

[0002] Pickling is a crucial step in the silicon steel production process, and its efficiency significantly impacts the output and quality of cold-rolled silicon steel production lines. The development of silicon steel pickling technology has progressed through deep-tank pickling, shallow-tank pickling, turbulent-flow pickling, variable-frequency turbulent-flow pickling, and now to the jet-based pickling process. However, shallow-tank turbulent-flow pickling remains the mainstream pickling technology. The purpose of pickling is to remove iron oxide scale from the surface of silicon steel. During continuous production, the concentration of the acid solution gradually decreases. To ensure the pickling quality of silicon steel products, new acid must be intermittently replenished to the unit's acid tank from the acid regeneration system, and waste acid that has been used for a period of time must be discharged from the acid tank to the acid regeneration system, based on parameters such as the pickling concentration. The discharge of waste acid from the acid tank to the acid regeneration system is mainly carried out through waste acid pumps and PPH pipelines. Due to the influence of plant layout, the distance from the pickling unit to the acid regeneration system varies, resulting in varying distances for waste acid pipelines, ranging from tens to hundreds of meters. During the pickling of silicon steel products, a large amount of silica sludge is generated. This silica sludge flows back into the acid tank with the acid solution and is then transported to acid regeneration via a waste acid pump. During the transportation process, the silica sludge settles and adheres to the inner wall of the pipe, causing the actual pipe diameter to decrease or even become blocked. The longer the pipe, the more serious the problem becomes, especially at vertical bends in the pipe. This results in a reduced waste acid discharge flow rate, and the waste acid in the unit's acid tank cannot be discharged in a timely manner, which will affect the production speed and product quality of pickling silicon steel products.

[0003] During normal operation, the unit sometimes discharges large amounts of waste acid into the wastewater pit to ensure production speed and product quality, causing secondary pollution to the wastewater discharge system and increasing wastewater treatment costs. Furthermore, during scheduled maintenance shutdowns, cleaning with high-pressure water, hydrofluoric acid, and room-temperature alkaline solution via pipe short-circuiting has minimal effect. To mitigate the severe impact of untimely waste acid discharge on production, the waste acid pipes need to be cut approximately 10 meters in length. Hard objects such as steel pipes are used to unclog and clean the silica sludge adhering to the inner walls of the pipes. After cleaning, the pipes are re-welded. However, when the pipes are cut, residual waste acid solution flows out and spills onto the land or green belts along the pipeline route, causing environmental pollution. The pipe-cutting process poses significant safety hazards and consumes considerable manpower and resources. Summary of the Invention

[0004] Purpose of the invention: The purpose of this invention is to provide a device for cleaning waste acid pipelines of silicon steel units, which aims to solve the problem that blockage of waste acid pipelines in silicon steel units causes low waste acid discharge flow, resulting in insufficient waste acid discharge from the unit, affecting the pickling quality of silicon steel products, and forcing the unit to limit production speed or discharge large amounts of waste acid into the sewage pit.

[0005] Technical solution: A device for cleaning waste acid pipelines of silicon steel units, including a 10m... 3 10m steel-lined rubber-lined alkali solution circulation tank 3 The steel-lined rubber-lined alkaline solution circulation tank has the following structure:

[0006] 10m 3 The steel-lined alkali solution circulation tank is equipped with PTFE-coated graphite nylon acid-resistant pipes inside, and steam is used to heat the alkali solution.

[0007] 10m 3 The top of the rubber-lined alkaline solution circulation tank is equipped with a guided wave radar level gauge to monitor the liquid level inside the tank.

[0008] 10m 3 The top of the rubber-lined alkaline solution circulating tank is equipped with a steam inlet and outlet pipe joint. The steam inlet pipe is connected to the Guangwang steam pipe, and a pneumatic regulating valve is installed on the pipe. The outlet pipe discharges into the ditch.

[0009] 10m 3 The top of the rubber-lined alkali circulation tank is equipped with a connector for cleaning waste acid pipelines and circulating it back to the alkali circulation tank, forming a closed loop for cleaning waste acid pipelines.

[0010] 10m 3 The steel-lined alkaline solution circulation tank is equipped with a pure water inlet pipe at the top for preparing the alkaline washing solution;

[0011] 10m 3 The top of the rubber-lined alkali solution circulation tank is equipped with an original alkali solution inlet pipe for alkali solution inlet;

[0012] 10m 3 The top of the rubber-lined alkali circulation tank is also equipped with a pipe connected to the acid mist system for the discharge of alkali mist and acid mist;

[0013] 10m 3 The bottom of the rubber-lined alkali solution circulating tank is equipped with a temperature transmitter, which detects temperatures up to 10 meters away. 3 The temperature of the alkaline solution in the rubber-lined alkaline solution circulation tank is interlocked with the pneumatic regulating valve of the steam inlet pipe for control.

[0014] 10m 3 The bottom of the rubber-lined alkali circulation tank is also equipped with a discharge port and an interface for connecting to the alkali circulation pump.

[0015] Furthermore, the device also includes an alkaline circulation pump, three waste acid pipelines, and a pressure transmitter and flow meter at the pump outlet. The pressure transmitter and pump are interlocked, and the flow meter can monitor the flow rate of the pipeline to determine the cleaning effect of the waste acid pipeline. The three waste acid pipelines are connected in series by pipes and valves. By switching the opening and closing of the valves, it can be determined whether to clean the silica sludge in two of the waste acid pipelines. When two of the waste acid pipelines are being cleaned, the other pipeline can still discharge waste acid normally, ensuring that the waste acid pipelines can be cleaned even when the unit is running normally.

[0016] Furthermore, a certain concentration of alkaline solution is prepared by mixing room-temperature alkaline solution with pure water. This alkaline solution is then heated by steam passing through a PTFE-coated graphite nylon acid-resistant tube inside the alkaline solution circulation tank. The heating temperature is determined based on the cleaning effect of the waste acid pipeline, and is controlled within the range of 50-80℃. The cleaning process of the waste acid pipeline does not affect the normal operation of the unit. The cleaning time depends on the cleaning effect of the pipeline and can be set to 6-12 hours. This allows for online cleaning of the waste acid discharge pipeline of the silicon steel unit. After alkaline washing, the silica sludge adhering to the inner wall of the waste acid pipeline is effectively removed, ensuring that the waste acid from the silicon steel unit can be smoothly discharged to acid regeneration, improving the stability of system operation, and also reducing the safety risks and environmental pollution caused by the waste acid pipeline cleaning process.

[0017] Beneficial effects: This invention enables online cleaning of waste acid pipelines in silicon steel units. While ensuring the discharge of waste acid from the unit's acid tank, it also guarantees the pickling speed and quality of silicon steel products. The circulating cleaning of waste acid pipelines avoids the need for cutting and cleaning of the pipelines, eliminating the safety risks associated with such abnormal operations. It also eliminates the pollution problems to the land and greenery along the waste acid pipeline route during the operation. Attached Figure Description

[0018] Figure 1 This is a process flow diagram of the waste acid pipeline cleaning process for silicon steel units according to the present invention.

[0019] In the picture:

[0020] 1. 10m 3 1. Steel-lined rubber alkaline solution circulation tank; 2. Temperature transmitter; 3. PTFE-coated graphite nylon acid-resistant tubing; 4. Steam trap; 5. Pneumatic regulating valve; 6. Shut-off valve; 7. Guided wave radar level gauge; 8. Ball valve; 9. Plastic manual butterfly valve; 10. Plastic manual butterfly valve; 11. Expansion joint; 12. Alkaline solution circulation pump; 13. Check valve; 14. Plastic manual butterfly valve; 15. Pressure transmitter; 16. Flow meter; 17~32. Plastic manual butterfly valve. Detailed Implementation

[0021] To make the technical solution of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] Example

[0023] This device is suitable for cleaning processes of waste acid pipelines in silicon steel units, such as... Figure 1 As shown, the specific process flow for cleaning waste acid pipelines No. 1 and No. 2 is as follows:

[0024] Step 1: According to the waste acid pipeline to be cleaned, adjust the valves connecting each waste acid pipeline, and close the plastic manual butterfly valves No. 19, 20, 21, 22, 24, 26, 31, and 32 to ensure that waste acid pipeline No. 3 can effectively discharge waste acid to acid regeneration.

[0025] Step 2: Open plastic manual butterfly valves 18, 28, and 30, and close plastic manual butterfly valves 25, 27, and 29 to ensure that the alkali circulation tank and the waste acid pipeline form a circulation loop.

[0026] Step 3: Add 5m³ of alkali solution to the alkali circulation tank 1 3 Pure water is introduced, and steam is introduced into the PTFE-coated graphite nylon acid-resistant tube 3 to heat the pure water in the alkaline solution circulation tank 1 to 50°C. The temperature of the liquid in the tank is detected by the temperature transmitter 2 and the steam is controlled by the pneumatic regulating valve 5.

[0027] Step 4: Start the alkali circulation pump 12 and flush and replace the residual waste acid solution in waste acid pipes No. 1 and No. 2 with pure water. The circulation time is 2-4 hours. During the circulation and replacement process, observe the flow rate of the flow meter 16. The pressure transmitter 15 detects the pressure at the outlet of the alkali circulation pump 12. If there is still no pressure after running for 10 seconds, the interlock trigger will stop the pump to prevent the alkali circulation pump 12 from being damaged by cavitation.

[0028] Step 5: After rinsing and replacement, open the plastic manual butterfly valve 9 to drain the solution in the alkali circulation tank 1 into the sewage ditch, and add pure water to clean the alkali circulation tank 1.

[0029] Step 6: Add alkali solution and pure water to the alkali solution circulation tank, depending on the original concentration of the alkali solution, such as 30% original alkali solution and 10m³ of pure water. 3 The volume of the alkali circulation tank is determined, the amount of alkali and pure water to be added is calculated, and finally the concentration of alkali in the alkali circulation tank is adjusted to 10%, and the alkali tank is filled with alkali.

[0030] Step 7: Steam is introduced into the PTFE-coated graphite nylon acid-resistant pipe 3 to heat the pure water in the alkaline solution circulation tank 1 to 50°C (the maximum temperature should not exceed 80°C depending on the alkaline washing effect of the waste acid pipeline). The temperature transmitter 2 detects the liquid temperature in the tank and controls the steam flow through the pneumatic regulating valve 5.

[0031] Step 8: Start the alkaline solution circulation pump 12 to perform alkaline washing on waste acid pipelines No. 1 and No. 2. The circulation time is 6-12 hours. During the alkaline washing process, observe the flow rate of the flow meter 16. The pressure transmitter 15 detects the pressure at the outlet of the alkaline solution circulation pump 12. If there is still no pressure after running for 10 seconds, the interlock trigger will stop the pump to prevent the alkaline solution circulation pump 12 from being damaged by cavitation.

[0032] Step 9: When the flow rate of flow meter 16 reaches the target value (not less than 80% of the rated flow rate of alkali circulation pump 12), stop alkali circulation pump 12 and close pneumatic regulating valve 5 to stop steam from entering the PTFE-coated graphite nylon acid-resistant tube 3. Open plastic manual butterfly valve 9 to drain the waste alkali in alkali circulation tank 1 into the sewage ditch.

[0033] Step 10: Add 5m3 of pure water to the alkali circulation tank 1 again, start the alkali circulation pump 12, and use pure water to flush and replace the residual waste alkali solution in waste acid pipes No. 1 and No. 2. The circulation time is about 1 hour.

[0034] Step 11: After rinsing and replacement, open the plastic manual butterfly valve 9 to drain the solution in the alkaline circulation tank 1 into the sewage ditch, and add pure water to clean the alkaline circulation tank 1.

[0035] Clean waste acid pipes No. 1 and No. 2, and waste acid pipes No. 2 and No. 3. Adjust the valves connecting each waste acid pipe, and then perform the above steps respectively.

[0036] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A device for cleaning waste acid pipelines in silicon steel units, characterized in that, Including 10m 3 10m steel-lined rubber-lined alkali solution circulation tank 3 The steel-lined rubber-lined alkali solution circulating tank has the following structure: 10m 3 The steel-lined rubber-lined alkali solution circulation tank is internally fitted with PTFE-coated graphite nylon acid-resistant tubing, and steam is used to heat the alkali solution; 10m 3 The top of the rubber-lined alkali solution circulation tank is equipped with a guided-wave radar level gauge to monitor the liquid level inside the tank; 10m 3 The steel-lined alkali solution circulating tank is equipped with steam inlet and outlet pipe joints at the top. The steam inlet pipe connects to the Guangwang steam pipeline, which is equipped with a pneumatic regulating valve. The outlet pipe discharges into a drainage ditch; 10m 3 The top of the rubber-lined steel alkaline solution circulation tank is equipped with a connector for the waste acid pipeline cleaning and circulation back to the alkaline solution circulation tank, forming a closed loop for cleaning the waste acid pipeline; 10m 3 The steel-lined rubber-lined alkali solution circulation tank is equipped with a pure water inlet pipe at the top for preparing the alkali washing solution; 10m 3 The steel-lined alkali circulation tank is equipped with a raw alkali inlet pipe at the top for alkali inlet feeding; 10m 3 The top of the rubber-lined alkali solution circulation tank is also equipped with a pipe connected to the acid mist system for the discharge of alkali mist and acid mist; 10m 3 The bottom of the rubber-lined alkali solution circulating tank is equipped with a temperature transmitter, which detects temperatures up to 10 meters away. 3 The temperature of the alkaline solution in the rubber-lined alkaline solution circulation tank is interlocked with the pneumatic regulating valve on the steam inlet pipeline for control; 10m 3 The bottom of the rubber-lined alkali circulation tank is also equipped with a discharge port and an interface for connecting to the alkali circulation pump.

2. The apparatus for cleaning waste acid pipelines of silicon steel units according to claim 1, characterized in that, The device also includes an alkaline circulation pump, three waste acid pipelines, and a pressure transmitter and flow meter at the pump outlet. The pressure transmitter and pump are interlocked, and the flow meter monitors the flow rate in the pipeline. The three waste acid pipelines are connected in series via pipes and valves. The opening and closing of the valves determines whether to clean the silica sludge in two of the waste acid pipelines. When two waste acid pipelines are being cleaned, the other pipeline discharges waste acid normally, ensuring that the waste acid pipelines can be cleaned even when the unit is running normally.

3. The apparatus for cleaning waste acid pipelines of silicon steel units according to claim 1, characterized in that, Alkali solution of a certain concentration is prepared by mixing room temperature alkaline solution with pure water. Then, the alkaline solution is heated by steam through a PTFE-coated graphite nylon acid-resistant tube in the alkaline solution circulation tank. The temperature is controlled within the range of 50-80℃. The cleaning time of the waste acid pipeline is set to 6-12 hours, thereby cleaning the waste acid discharge pipeline of the silicon steel unit online.

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