Up-drawing furnace cleaning device and cleaning method thereof

Abstract

The invention discloses an up-drawing furnace cleaning device and a cleaning method thereof, and belongs to the technical field of copper smelting in the nonferrous metal industry. Comprising a tank body and a water cooling jacket / coil water return pipeline, a corrosion-resistant self-priming pump is installed on the side wall of the tank body, the interior of the tank body is divided into a cleaning fluid tank and a sewage tank through a vertical partition plate, a cover plate is arranged at the top of the tank body, a water inlet is formed in the cover plate and located above the sewage tank, and a filtering funnel is arranged at the water inlet. An outlet end of a water cooling jacket / coil water return pipeline 7 enters from a water inlet in the cover plate and is positioned in the filtering funnel, a water inlet of the corrosion-resistant self-priming pump is communicated with a cleaning liquid tank in the tank body through a cleaning liquid circulating pipeline, and a water outlet of the corrosion-resistant self-priming pump is respectively communicated with a water cooling jacket / coil interface and the circulating pipeline through a high-temperature-resistant hose and a three-way joint; and an outlet of the circulating pipeline is positioned in the cleaning liquid tank in the tank body. The maintenance time is shortened; the maintenance cost is reduced; equipment damage is avoided; the environmental protection property is improved; and the cleaning effect is guaranteed.

Description

Technical Field

[0001] This invention relates to the field of copper processing equipment maintenance technology, specifically to an upward drawing furnace cleaning device and its cleaning method, applicable to the scaling cleaning and maintenance of the upward drawing furnace power frequency induction system, and particularly to an online cleaning device and its cleaning method for the water-cooled coil and water jacket of the upward drawing continuous casting furnace. Background Technology

[0002] Upward continuous casting is the core process for the copper processing industry to convert cathode copper into copper rods. Its production process is as follows: cathode copper is put into a combined melting furnace and melted into copper liquid by power frequency induction heating; the copper liquid overflows smoothly into the holding furnace through the transition chamber, and after deoxygenation and reduction treatment, it is cast into qualified copper rods by the continuous casting machine.

[0003] The power frequency induction system of the upward-drawing furnace is a key piece of equipment for melting molten copper. Its core structure consists of a shell, water-cooled coils, a water jacket, a U-shaped iron core, and a molten groove. The high-voltage side (primary) of the inductor is composed of the water-cooled coil, while the low-voltage side (secondary) is composed of a short-circuited coil molten groove. When energized, electromagnetic induction generates a large current and low voltage within the molten groove, ultimately melting the electrolytic copper. The water-cooled coils and water jacket are the core heat dissipation components of the system; their heat dissipation efficiency directly determines the continuous production stability of the upward-drawing furnace and the quality of the copper rod forming.

[0004] In actual production, the cooling water for water-cooled coils and water jackets needs to be circulated in a high-temperature environment for extended periods. This causes minerals and impurities such as calcium carbonate and magnesium hydroxide in the water to deposit and form scale on the inner walls of the components. As the scale thickness increases, the flow cross-section of the pipeline narrows, eventually leading to blockage. Current technologies generally employ a solution of "completely replacing the water jacket and water-cooled coils," but this solution has significant drawbacks. It is not only costly to maintain but also prone to damaging the equipment and is complex to operate. Specifically, the disadvantages of existing technologies are as follows: 1. Long downtime: Traditional replacement methods result in a single downtime of 48 hours, far exceeding the acceptable maintenance time for production (the industry's standard acceptable downtime is ≤8 hours), leading to frequent production interruptions; High maintenance costs: A single replacement costs 8,000 yuan, with an average annual maintenance cost of 32,000 yuan per unit, far exceeding the industry average equipment maintenance cost ratio; 2. Strong reliance on spare parts: Spare parts procurement cycle is 15 days, leading to blockages. The process involves several drawbacks: 1. Long waiting time for spare parts, further extending downtime and impacting production plans; 2. Significant equipment damage: During disassembly and installation of the water jacket, collisions and wear are common with the furnace shell and core, shortening the overall service life of the upward-drawing furnace (an average of 1-2 years shorter annually due to replacement); 3. Significant damage: During disassembly and installation, the water jacket is prone to collisions and wear with the furnace shell and core, leading to a decrease in the furnace structure's precision and shortening the overall service life of the upward-drawing furnace; 4. High operational complexity: The replacement process requires the coordinated work of multiple technicians and demands high installation precision. Excessive assembly deviation can easily lead to subsequent coil insulation failures.

[0005] To address the above problems, we propose a cleaning device and cleaning method suitable for upward-drawing furnaces. Summary of the Invention

[0006] The purpose of this invention is to provide an upward-drawing furnace cleaning device and method to achieve the following objectives: Reduce maintenance time: reduce downtime for a single blockage treatment from 48 hours to less than 4 hours, meeting industry requirements for continuous production; Reduce maintenance costs: reduce the cost of a single maintenance from 8,000 yuan to less than 800 yuan, and the average annual maintenance cost to less than 3,200 yuan per unit; Avoid equipment damage: adopt an online cleaning mode, eliminating the need to disassemble and replace the water jacket and water-cooled coil, thus eliminating the risk of furnace body collision and wear during disassembly; Improve environmental friendliness: achieve a cleaning fluid reuse rate of ≥85%, reducing waste liquid discharge and lowering environmental protection pressure; Ensure cleaning effect: after cleaning, the flow recovery rate of the water jacket and water-cooled coil is ≥95%, meeting the production process requirements of the upward-drawing furnace (industry standard ≥90%), ensuring stable heat dissipation efficiency.

[0007] The technical solution adopted in this invention is as follows:

[0008] A top-feed furnace cleaning device includes a tank 1 and a water-cooled jacket / coil return water pipe 7. A corrosion-resistant self-priming pump 3 is installed on the side wall of the tank 1. The interior of the tank 1 is divided into a cleaning liquid tank and a wastewater tank by a vertical partition. A cover plate 2 is provided on the top of the tank 1. An inlet is provided above the wastewater tank on the cover plate 2. A filter funnel 8 is provided at the inlet. The outlet end of the water-cooled jacket / coil return water pipe 7 enters from the inlet on the cover plate 2 and is located in the filter funnel 8. The inlet of the corrosion-resistant self-priming pump 3 is connected to the cleaning liquid tank in the tank 1 through a cleaning liquid circulation pipe. The outlet of the corrosion-resistant self-priming pump 3 is connected to the water-cooled jacket / coil interface 11 and the circulation pipe 9 through a high-temperature resistant hose and a tee connector, respectively. The outlet of the circulation pipe 9 is located in the cleaning liquid tank in the tank 1. The high-temperature resistant hose connects the centrifugal pump outlet and the water jacket / coil inlet to accommodate the equipment installation gap.

[0009] A distribution box 6 is installed on the side wall of the tank 1. The distribution box 6 is equipped with a socket and an air switch. The socket is used to connect the power supply. The inlet of the air switch is connected to the power supply of the socket, and the outlet is connected to the corrosion-resistant self-priming pump wire, which is used to control the start or stop of the corrosion-resistant self-priming pump.

[0010] The bottom of the tank 1 is provided with a drain outlet 4 equipped with a valve at the cleaning liquid tank and a sewage drain outlet 5 equipped with a valve at the sewage tank at the bottom of the tank 1.

[0011] A sampling port is provided at the cleaning fluid tank on the side wall of the tank 1.

[0012] The tank 1 is made of 316L stainless steel, and the pump body of the corrosion-resistant self-priming pump 3 is made of fluoroplastic alloy.

[0013] A filter screen is installed at the bottom of the cleaning fluid tank inside the tank 1, and the inlet of the cleaning fluid circulation pipe is located below the filter screen.

[0014] The high-temperature resistant hose has an inner layer of nitrile rubber and an outer layer of stainless steel braided mesh. The inner diameter of the high-temperature resistant hose is 25mm. The water cooling jacket / coil return water pipe 7 is made of 304 stainless steel and has an inner diameter of 25mm.

[0015] A pressure gauge 10 is installed on the high-temperature resistant hose.

[0016] Valves are installed on the outlet of the corrosion-resistant self-priming pump 3, the water-cooled jacket / coil return water pipe 7, and the water-cooled jacket / coil interface 11. The valve body is made of 304 stainless steel and the valve core is made of polytetrafluoroethylene.

[0017] The cleaning method of the upward drawing furnace cleaning device includes the following steps:

[0018] S1. Pre-rinse: Turn on the corrosion-resistant self-priming pump, adjust the outlet valve of the corrosion-resistant self-priming pump to control the flow rate at 4-6 m³ / h, and pump the composite cleaning solution into the water jacket and water-cooled coil.

[0019] The composite cleaning solution is a composite formula of "oxalic acid + citric acid + special scale inhibitor", with the following mass percentages of each component: oxalic acid 4% to 6%, citric acid 2% to 4%, and special scale inhibitor 0.4% to 0.6%. The special scale inhibitor is hydroxyethylidene diphosphonic acid.

[0020] S2. Main Wash: Adjust the outlet valve of the corrosion-resistant self-priming pump to increase the flow rate to 8-12 m³ / h, and keep the cleaning solution circulating in the closed system; during this period, check the concentration of the cleaning solution through the sampling port of the tank every 30 minutes. If the oxalic acid concentration is lower than 3%, add oxalic acid stock solution to bring it up to 5%.

[0021] Monitoring indicators: The flow rate of the return pipeline is monitored in real time by a flow meter. When the flow rate is stable and reaches more than 95% of the initial flow rate before cleaning, the main cleaning is considered to be completed.

[0022] S3. Passivation: Adjust the pump outlet valve to reduce the flow rate to 4-6 m³ / h, and use the residual citric acid in the cleaning solution to form a passivation film with a thickness of 5-10 μm on the water jacket and inner wall of the coil.

[0023] After passivation is complete, turn off the centrifugal pump and discharge the cleaning solution from the bottom outlet of the tank to a sealed storage tank (it can be used for the next cleaning, with a reuse rate of ≥85%). Finally, rinse the water jacket / coil with clean water for 10 minutes to drain any residual cleaning solution. After cleaning, the flow rate recovery rate of the water jacket and water-cooled coil is ≥95%.

[0024] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0025] (a) Technical effects

[0026] 1. Significantly reduced downtime: Downtime for a single maintenance session was reduced from 48 hours to less than 4 hours, improving efficiency by 83%; the average annual unplanned downtime per unit was reduced by 176 hours, significantly improving production continuity;

[0027] 2. Cleaning effect meets standards: After cleaning, the flow recovery rate of the water jacket and water-cooled coil is ≥95%, which is higher than the industry standard (≥90%) and close to the 100% flow recovery rate of new spare parts, fully meeting the heat dissipation requirements of the upper drawing furnace;

[0028] 3. Zero damage to equipment: The online cleaning mode eliminates the need to replace the water jacket and water-cooled coil, avoiding collisions and wear on the furnace shell and the I-shaped iron core during disassembly, and is expected to extend the overall service life of the upward drawing furnace by 2-3 years.

[0029] (ii) Economic effects

[0030] 1. Maintenance costs plummeted: The cost of a single maintenance session dropped from 8,000 yuan to less than 800 yuan, a decrease of 90%; the average annual maintenance cost per unit dropped from 32,000 yuan to 3,200 yuan, resulting in annual savings of 28,800 yuan.

[0031] 2. Significant increase in output value: The average annual reduction in copper rod production loss is 360 tons / unit. Based on the industry average copper rod price of 50,000 yuan / ton, the annual increase in output value is 18 million yuan / unit.

[0032] 3. Quick return on investment: The total investment for the equipment is only 15,000 yuan. Based on the annual savings of 28,800 yuan per unit, the investment payback period is only 4 months.

[0033] (III) Environmental and social benefits

[0034] 1. Reduced waste emissions: The annual amount of scrapped water jackets and water-cooled coils is reduced by 3.2 tons / unit, reducing the pressure on metal waste disposal and meeting the requirements of green production;

[0035] 2. Reduce environmental pressure: The cleaning solution reuse rate is ≥85%, and only a small amount of original solution needs to be added for each cleaning, reducing waste liquid discharge (an average reduction of 10m³ / unit of waste liquid discharge per year), and reducing the company's environmental treatment costs;

[0036] 3. Enhance resilience: Eliminate the need for frequent procurement of water jacket / coil spare parts, reduce supply chain dependence, avoid long-term downtime due to spare parts shortages, and enhance the company's resilience to production risks. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the structure of the present invention;

[0038] In the diagram: 1. Tank; 2. Cover plate; 3. Corrosion-resistant self-priming pump; 4. Drain outlet; 5. Sewage drain outlet; 6. Distribution box; 7. Water-cooled jacket / coil return water pipe; 8. Filter funnel; 9. Circulation pipe; 10. Pressure gauge; 11. Water-cooled jacket / coil interface. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0040] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0041] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0042] Example 1

[0043] like Figure 1 As shown, this embodiment provides an upward-drawing furnace cleaning device, including a tank 1 and a water-cooled jacket / coil return water pipe 7. A corrosion-resistant self-priming pump 3 is installed on the side wall of the tank 1. The interior of the tank 1 is divided into a cleaning liquid tank and a sewage tank by a vertical partition. A cover plate 2 is provided on the top of the tank 1. An inlet is provided above the sewage tank on the cover plate 2. A filter funnel 8 is provided at the inlet. The outlet end of the water-cooled jacket / coil return water pipe 7 enters from the inlet on the cover plate 2 and is located in the filter funnel 8. The filter funnel 8 can remove impurities in the sewage of the water-cooled jacket / coil. The inlet of the corrosion-resistant self-priming pump 3 is connected to the cleaning liquid tank inside the tank 1 through a cleaning liquid circulation pipe. The outlet of the corrosion-resistant self-priming pump 3 is connected to the water-cooled jacket / coil interface 11 and the circulation pipe 9 through a high-temperature resistant hose and a tee connector, respectively. The outlet of the circulation pipe 9 is located in the cleaning liquid tank inside the tank 1.

[0044] A distribution box 6 is installed on the side wall of the tank 1. The distribution box 6 is equipped with a socket and an air switch. The socket is used to connect the power supply. The air switch is connected to the power supply of the socket at the inlet and to the self-priming pump wire at the outlet, which is used to control the start or stop of the self-priming pump.

[0045] The bottom of the tank 1 is provided with a drain outlet 4 equipped with a valve at the cleaning liquid tank and a sewage drain outlet 5 equipped with a valve at the sewage tank at the bottom of the tank 1.

[0046] A sampling port is provided at the cleaning fluid tank on the side wall of the tank body 1. The sampling port is used to take samples at any time to test the concentration of the cleaning fluid.

[0047] The tank 1 is made of 316L stainless steel, with a volume of 1.5 m³, an inner diameter of 1500 mm, and a height of 1500 mm. The corrosion-resistant self-priming pump 3 has a pump body made of fluoroplastic alloy, a rated flow rate of 8-12 m³ / h, a head of 15 m, a voltage of 220 V, and a power of 3 kW. The corrosion-resistant self-priming pump 3 provides power for the circulation of the cleaning fluid, pumping the cleaning fluid into the water jacket and coil.

[0048] A filter screen is installed at the bottom of the cleaning fluid tank inside the tank 1, and the inlet of the cleaning fluid circulation pipe is located below the filter screen. The cleaning fluid is recycled after being filtered by the filter screen at the bottom of the cleaning fluid tank. The filter screen is used to filter loose dirt during the pre-rinse stage.

[0049] The high-temperature resistant hose has an inner layer of nitrile rubber and an outer layer of stainless steel braided mesh. Its inner diameter is 25mm, and its operating temperature ranges from -20℃ to 120℃. The water-cooled jacket / coil return water pipe 7 is made of 304 stainless steel, has an inner diameter of 25mm, and its length is adapted to the actual dimensions. It returns the cleaning fluid flowing out of the water jacket / coil to the tank, forming a circulation.

[0050] A pressure gauge 10 is installed on the high-temperature resistant hose.

[0051] Valves are installed at the outlet of the corrosion-resistant self-priming pump 3, on the water-cooled jacket / coil return water pipe 7, and on the water-cooled jacket / coil interface 11. The valve body is made of 304 stainless steel, and the valve core is made of polytetrafluoroethylene. The valves are used to adjust the cleaning fluid flow rate and switch the cleaning path (single-channel cleaning / multi-channel simultaneous cleaning).

[0052] The cleaning process steps of the upward furnace cleaning device are as follows:

[0053] 1. Pre-rinse stage (duration 0.4-0.6 hours, preferably 0.5 hours)

[0054] Operating steps: Turn on the corrosion-resistant self-priming pump, adjust the outlet valve of the corrosion-resistant self-priming pump to control the flow rate at 4-6 m³ / h (preferably 5 m³ / h), and pump the composite cleaning solution into the water jacket and water-cooled coil.

[0055] The composite cleaning solution used is a compound formula of "oxalic acid + citric acid + special scale inhibitor". The mass percentage of each component is as follows: oxalic acid 4% to 6%, citric acid 2% to 4%, and special scale inhibitor 0.4% to 0.6%. The special scale inhibitor is hydroxyethylidene diphosphonic acid (HEDP).

[0056] Function: To flush out loose dirt (such as deposits with a particle size ≤1mm) in the pipeline, and prevent loose dirt from clogging the small channels of the water jacket / coil during the main wash stage;

[0057] Circulation path: 316L stainless steel tank → corrosion-resistant centrifugal pump → high-temperature resistant hose → water jacket / coil inlet → inside of water jacket / coil → water-cooled jacket / coil return water pipe → 316L stainless steel tank (the cleaning solution is recycled after being filtered by the filter screen at the bottom of the tank).

[0058] 2. Main wash stage (duration 2.8-3.2 hours, preferably 3 hours)

[0059] Operating procedures: Adjust the outlet valve of the corrosion-resistant self-priming pump to increase the flow rate to 8-12 m³ / h (adapt to the scale thickness: 8 m³ / h for light scale, 10 m³ / h for moderate scale, and 12 m³ / h for heavy scale), and keep the cleaning solution circulating in the closed system; during this period, check the concentration of the cleaning solution every 30 minutes through the sampling port in the tank. If the oxalic acid concentration is lower than 3%, add oxalic acid stock solution to bring it up to 5%.

[0060] Function: Through the synergistic effect of oxalic acid and citric acid, it dissolves hard and stubborn scale on the inner wall of the water jacket / coil, while the scale inhibitor simultaneously inhibits the formation of new scale;

[0061] Monitoring indicators: The flow rate of the return pipeline is monitored in real time by a flow meter. When the flow rate is stable (fluctuation ≤5%) and reaches more than 95% of the initial flow rate before cleaning, the main cleaning is considered to be completed.

[0062] 3. Passivation stage (duration 0.4 to 0.6 hours, preferably 0.5 hours)

[0063] Operating steps: Adjust the pump outlet valve to reduce the flow rate to 4-6 m³ / h (preferably 5 m³ / h), and use the residual citric acid in the cleaning solution to form a passivation film with a thickness of 5-10 μm on the water jacket and inner wall of the coil.

[0064] Function: The passivation film prevents the inner metal wall from directly contacting the cooling water, thus avoiding oxidation and corrosion;

[0065] Subsequent processing: After passivation, turn off the centrifugal pump and discharge the cleaning solution from the bottom outlet of the tank to a sealed storage tank (it can be used for the next cleaning, with a reuse rate of ≥85%); finally, rinse the water jacket / coil with clean water for 10 minutes to drain any residual cleaning solution. After cleaning, the flow rate recovery rate of the water jacket and water-cooled coil is ≥95%.

[0066] Example 1

[0067] For lightly scaled samples, clean the furnace (scale thickness 1-2 mm).

[0068] 1. Composition parameters of this cleaning device

[0069] 316L stainless steel tank: filled with 0.7m³ of composite cleaning solution;

[0070] Corrosion-resistant centrifugal pump: set flow rate 8m³ / h (main washing stage), 5m³ / h (pre-rinse / passivation stage);

[0071] Control valves: Open the water jacket interface valve and the coil interface valve to adopt the "dual-path simultaneous cleaning" mode.

[0072] 2. Process Steps

[0073] Pre-rinsing stage: 0.5 hours, flow rate 5 m³ / h, after rinsing, the loose dirt content in the return liquid is ≤0.1%;

[0074] Main wash phase: 2.8 hours, flow rate 8 m³ / h, with samples taken every 30 minutes during the wash. The oxalic acid concentration remained stable at 4.8%–5.2%, and no replenishment of the stock solution was required.

[0075] Passivation stage: 0.5 hours, flow rate 5 m³ / h, passivation film thickness was measured to be 8 μm after passivation.

[0076] 3. Effects

[0077] Total downtime: 3.8 hours (≤4 hours);

[0078] Flow recovery rate: water jacket flow recovery rate 96%, coil flow recovery rate 97%;

[0079] Maintenance cost: 750 yuan per operation (including replenishment of original solution and electricity).

[0080] Cleaning solution reuse: The cleaning solution is exported and stored, and can be used directly for the next cleaning, with a reuse rate of 88%.

[0081] Example 2:

[0082] For moderately scaled furnaces (scale thickness 3-5 mm), perform cleaning.

[0083] 1. Device configuration parameters

[0084] 316L stainless steel tank: filled with 1.5m³ of composite cleaning solution, the formula of which is 6% oxalic acid, 4% citric acid, and 0.6% special scale inhibitor;

[0085] Corrosion-resistant centrifugal pump: set flow rate 10m³ / h (main washing stage), 5m³ / h (pre-rinse / passivation stage);

[0086] Control valves: First open the water jacket interface valve (single-channel cleaning of the water jacket), then open the coil interface valve (single-channel cleaning of the coil), adopting the "single-channel sequential cleaning" mode.

[0087] 2. Process Steps

[0088] Pre-rinsing stage: 0.6 hours, flow rate 5m³ / h, after rinsing, approximately 0.5kg of loose dirt is filtered out through the filter screen;

[0089] Main wash phase: 3.0 hours, flow rate 10 m³ / h. After 1.5 hours of main wash, the oxalic acid concentration dropped to 3.8%. 0.03 m³ of oxalic acid stock solution was added, and the concentration rose back to 5.9%.

[0090] Passivation stage: 0.6 hours, flow rate 5 m³ / h, after passivation, the metal corrosion rate was measured to be 0.04 mm / a.

[0091] 3. Effects

[0092] Total downtime: 4.2 hours (after fine-tuning, it can be controlled within 4 hours by compressing the pre-rinse time to 0.4 hours);

[0093] Flow recovery rate: water jacket flow recovery rate 95%, coil flow recovery rate 96%;

[0094] Maintenance cost: 780 yuan per operation (including replenishment of original solution and electricity).

[0095] Equipment status: The furnace shell was undamaged after cleaning, and the water jacket and coil were properly assembled.

[0096] Example 3:

[0097] For heavily scaled samples, clean the furnace (scale thickness 6-8 mm).

[0098] 1. Device configuration parameters

[0099] 316L stainless steel tank: filled with 1.5m³ of composite cleaning solution, the formula of which is 6% oxalic acid, 4% citric acid, and 0.6% special scale inhibitor;

[0100] Corrosion-resistant centrifugal pump: set flow rate 12m³ / h (main washing stage), 6m³ / h (pre-rinse / passivation stage);

[0101] Auxiliary components: A descaling filter (0.5mm aperture) is added to the return pipeline to prevent large scale from clogging the pump body.

[0102] 2. Process Steps

[0103] Pre-rinse stage: 0.6 hours, flow rate 6m³ / h, flushing out approximately 1.2kg of large scale (particle size 2-5mm), which is then filtered through the auxiliary filter screen;

[0104] Main wash phase: 3.2 hours, flow rate 12 m³ / h, during which oxalic acid stock solution is added twice (0.04 m³ each time) to maintain the oxalic acid concentration at 5.5%–6.0%;

[0105] Passivation stage: 0.6 hours, flow rate 6 m³ / h. After passivation, the smoothness of the inner wall of the water jacket was tested, and no residual scale was found.

[0106] 3. Effects

[0107] Total downtime: 4.4 hours (reduced to within 4 hours by parallel operation of "cleaning fluid replenishment" and "flow monitoring");

[0108] Flow recovery rate: Water jacket flow recovery rate 95%, coil flow recovery rate 95%, meeting production requirements;

[0109] Long-term results: After a 3-month follow-up after cleaning, no new scale was formed on the water jacket and coil, and the flow rate remained stable at 94%–96% of the initial value;

[0110] Cost comparison: Compared with the traditional replacement solution (0.8 million yuan / time), the cost is reduced by 7,220 yuan per time. Based on an average of 4 cleanings per year, the annual savings are 28,880 yuan.

Claims

1. A cleaning device for an upward-drawing furnace, comprising a tank (1) and a water-cooled jacket / coil return water pipe (7), characterized in that, A corrosion-resistant self-priming pump (3) is installed on the side wall of the tank (1). The inside of the tank (1) is divided into a cleaning liquid tank and a sewage tank by a vertical partition. A cover plate (2) is provided on the top of the tank (1). An inlet is provided above the sewage tank on the cover plate (2). A filter funnel (8) is provided at the inlet. The outlet end of the water-cooled jacket / coil return water pipe (7) enters from the inlet on the cover plate (2) and is located in the filter funnel (8). The inlet of the corrosion-resistant self-priming pump (3) is connected to the cleaning liquid tank in the tank (1) through the cleaning liquid circulation pipe. The outlet of the corrosion-resistant self-priming pump (3) is connected to the water-cooled jacket / coil interface (11) and the circulation pipe (9) through a high-temperature resistant hose and a three-way connector, respectively. The outlet of the circulation pipe (9) is located in the cleaning liquid tank in the tank (1).

2. The upward drawing furnace cleaning device according to claim 1, characterized in that, A distribution box (6) is installed on the side wall of the tank (1). The distribution box (6) is equipped with a socket and an air switch. The socket is used to connect the power supply. The air switch is connected to the power supply of the socket at the inlet and to the corrosion-resistant self-priming pump wire at the outlet, which is used to control the start or stop of the corrosion-resistant self-priming pump.

3. The upward drawing furnace cleaning device according to claim 1, characterized in that, The bottom of the tank (1) is provided with a drain outlet (4) with a valve installed at the cleaning liquid tank, and the bottom of the tank (1) is provided with a sewage drain outlet (5) with a valve installed at the sewage tank.

4. The upward drawing furnace cleaning device according to claim 1, characterized in that, The tank (1) has a sampling port at the cleaning liquid tank on its side wall.

5. The upward drawing furnace cleaning device according to claim 1, characterized in that, The tank (1) is made of 316L stainless steel, and the pump body of the corrosion-resistant self-priming pump (3) is made of fluoroplastic alloy.

6. The upward drawing furnace cleaning device according to claim 1, characterized in that, A filter screen is installed at the bottom of the cleaning fluid tank in the tank (1), and the inlet of the cleaning fluid circulation pipe is located below the filter screen.

7. The upward drawing furnace cleaning device according to claim 1, characterized in that, The inner layer of the high-temperature resistant hose is nitrile rubber and the outer layer is stainless steel braided mesh. The inner diameter of the high-temperature resistant hose is 25mm. The water cooling jacket / coil return water pipe (7) is made of 304 stainless steel and has an inner diameter of 25mm.

8. The upward drawing furnace cleaning device according to claim 1, characterized in that, A pressure gauge (10) is installed on the high-temperature resistant hose.

9. The upward drawing furnace cleaning device according to claim 1, characterized in that, Valves are installed on the outlet of the corrosion-resistant self-priming pump (3), the water cooling jacket / coil return water pipe (7), and the water cooling jacket / coil interface (11). The valve body is made of 304 stainless steel and the valve core is made of polytetrafluoroethylene.

10. A cleaning method for an upward-drawing furnace cleaning device according to any one of claims 1-9, characterized in that, Includes the following steps: S1. Pre-rinse: Turn on the corrosion-resistant self-priming pump, adjust the outlet valve of the corrosion-resistant self-priming pump to control the flow rate at 4-6 m³ / h, and pump the composite cleaning solution into the water jacket and water-cooled coil. The composite cleaning solution is a composite formula of "oxalic acid + citric acid + special scale inhibitor", with the following mass percentages of each component: oxalic acid 4% to 6%, citric acid 2% to 4%, and special scale inhibitor 0.4% to 0.6%. The special scale inhibitor is hydroxyethylidene diphosphonic acid. S2. Main Wash: Adjust the outlet valve of the corrosion-resistant self-priming pump to increase the flow rate to 8-12 m³ / h, and keep the cleaning solution circulating in the closed system; during this period, check the concentration of the cleaning solution through the sampling port of the tank every 30 minutes. If the oxalic acid concentration is lower than 3%, add oxalic acid stock solution to bring it up to 5%. Monitoring indicators: The flow rate of the return pipeline is monitored in real time by a flow meter. When the flow rate is stable and reaches more than 95% of the initial flow rate before cleaning, the main cleaning is considered to be completed. S3. Passivation: Adjust the pump outlet valve to reduce the flow rate to 4-6 m³ / h, and use the residual citric acid in the cleaning solution to form a passivation film with a thickness of 5-10 μm on the water jacket and inner wall of the coil. After passivation is complete, turn off the centrifugal pump and discharge the cleaning solution from the bottom outlet of the tank to a sealed storage tank (it can be used for the next cleaning, with a reuse rate of ≥85%). Finally, rinse the water jacket / coil with clean water for 10 minutes to drain any residual cleaning solution. After cleaning, the flow rate recovery rate of the water jacket and water-cooled coil is ≥95%.

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