Multi-stage monitoring strongly acidic chromium-containing waste liquid storage device with nested structure

Abstract

The invention relates to the technical field of waste liquid storage equipment, in particular to a multi-stage monitoring strongly acidic chromium-containing waste liquid storage device of a nested structure, which comprises a storage tank main body, the storage tank main body is composed of an outer barrel and an inner barrel of a nested structure, the inner barrel is made of a corrosion-resistant material, and the outer barrel and the inner barrel are both of a closed structure; the inner barrel is connected with a waste liquid discharge pipeline of superior equipment, an outlet pipeline used for being externally connected with a transportation barrel, an exhaust pipe used for exhausting waste gas and a liquid level pipe used for displaying the liquid level of the inner barrel through connectors on the outer barrel; the liquid level pipe is provided with a liquid level sensor; a liquid receiving disc used for receiving leaked liquid is arranged below the outer barrel, and the liquid receiving disc is provided with a leaked liquid sensor; the liquid level sensor and the liquid leakage sensor are both connected with the control system, and when detection data of the liquid level sensor or the liquid leakage sensor triggers a set threshold value, the control system starts the alarm device and closes the waste discharge valve of the waste liquid discharge pipeline.

Description

Technical Field

[0001] This invention relates to the field of waste liquid storage equipment technology, specifically to a multi-level monitoring device for storing strongly acidic chromium-containing waste liquid with a nested structure. Background Technology

[0002] Currently, the industry standard for storing chromium-containing waste liquids is to use 304 stainless steel containers or PVC containers. However, these storage devices have significant drawbacks in highly oxidizing environments containing hexavalent chromium with a pH < 1. According to the accelerated corrosion test in Appendix B of the national recommended standard GB / T 4334-2020 and industry practice, the corrosion rate of 304 stainless steel in strongly acidic chromium-containing waste liquid increases significantly, reaching 5 mm / year under extreme conditions, which will lead to the risk of perforation of the inner wall of the container within 3 months. In addition, Q345R steel has an annual corrosion rate of 1.2 mm / year in the same corrosive environment (pH=0.5, 50℃), which is better than Q235 steel (2.5 mm / year), but it still needs to be used with anti-corrosion materials to achieve complete protection; PVC material is prone to deformation at high temperatures (>50℃), which can lead to sealing failure. According to the technical specification for the collection, storage and transportation of hazardous waste, "HJ 2025-2012", the leakage response time is required to be ≤30 seconds. However, in the industry's conventional solutions, due to the simple sensor layout and lack of signal fusion, the actual response time is mostly 20-40 seconds, and the false alarm rate is >15%.

[0003] In addition, although precious metal (such as titanium alloy) liners can be used to improve the corrosion resistance of storage devices, their cost is more than 10 times that of stainless steel, making them difficult to popularize. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a nested structure multi-level monitoring storage device for strongly acidic chromium-containing waste liquid, which has strong corrosion resistance and long service life, fast monitoring response speed for waste liquid leakage, and relatively low cost.

[0005] The technical solution of this invention is: A multi-level monitoring storage device for strongly acidic chromium-containing waste liquid with a nested structure includes a storage tank body, which is composed of an outer tank and an inner tank with a nested structure. The inner tank is made of corrosion-resistant material, and both the outer tank and the inner tank are closed structures. The inner tank is connected to the following via several interfaces on the outer tank: a waste liquid discharge pipe of the upper-level equipment, an outlet pipe for connecting external transport tanks, an exhaust pipe for discharging waste gas, and a liquid level pipe for displaying the liquid level of the inner tank; the liquid level pipe is equipped with at least one liquid level sensor. The outer barrel is provided with a liquid receiving tray for catching leaks, and the liquid receiving tray is equipped with at least one leak sensor. Both the liquid level sensor and the leakage sensor are connected to the control system. When the detection data of the liquid level sensor or the leakage sensor triggers a set threshold, the control system activates the alarm device and closes the waste discharge valve of the waste liquid discharge pipeline.

[0006] Preferably, the outer barrel is mounted on a support, thereby raising the height of the outlet pipe and facilitating the connection of an external transport barrel.

[0007] Preferably, the outer barrel is made of Q345R steel plate.

[0008] Preferably, the inner barrel is made of polytetrafluoroethylene.

[0009] Preferably, the top of the outer barrel is a barrel opening with a flange, and the barrel opening is closed by a flange cover. The sealing surfaces of the flange cover and the flange are sealed with corrosion-resistant gaskets.

[0010] Preferably, an exhaust hood is provided above the opening of the barrel, and the exhaust hood is connected to the waste gas treatment system.

[0011] Preferably, the exhaust pipe is connected to the exhaust gas treatment system.

[0012] Preferably, the bottom of the inner tub is provided with a support component to prevent the bottom of the inner tub from directly contacting the outer tub.

[0013] Preferably, at least one of the neck, top, body, and bottom of the outer barrel is provided with a positioning bolt. The inner ends of the positioning bolts of the neck, top, and body abut against the outer wall of the corresponding part of the inner barrel, and the positioning bolts of the bottom abut against the supporting component.

[0014] Preferably, the support component is a support ring made of polytetrafluoroethylene.

[0015] The present invention has the following beneficial effects: (1) Waste liquid is stored in an inner tank made of polytetrafluoroethylene (PTFE), which has about 10 times better corrosion resistance than 304 stainless steel and costs only 20% of titanium alloy; (2) By coordinating the monitoring of the liquid level sensor and the leakage sensor (liquid level change detection + leakage physical contact) with the control system, leakage detection from macro leakage to micro leakage can be realized. The response time is ≤10 seconds, which meets the requirements of HJ 2025-2012 and reduces the response time by about 2 / 3, greatly reducing the risk of leakage. (3) The outer barrel is made of Q345R low alloy high strength steel plate (compliant with GB 713-2014), with a yield strength ≥345MPa, which is more than 30% higher than ordinary carbon steel (such as Q235), which can reduce the wall thickness and maintain the structural strength; at the same time, the inner barrel of PTFE is nested to achieve complete isolation from corrosive media, and the outer barrel only bears pressure and avoids direct contact with acidic waste liquid.

[0016] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments of the present invention will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a structural schematic diagram of an embodiment of the present invention.

[0019] Figure 2 This is a schematic diagram of the installation structure of the outer barrel, inner barrel, and positioning bolts in the barrel body of this invention.

[0020] Reference numerals in the attached drawings: 1. Tank body, 1.1. Outer tank, 1.2. Inner tank, 2. Inlet, 3. Outlet, 4. Waste liquid discharge pipe, 5. Exhaust pipe, 6. Exhaust hood, 7. Flange cover, 8. Corrosion resistant gasket, 9. Tank neck, 10. Supporting component, 11. Bracket, 12. Liquid receiving tray, 13. Leakage sensor, 14. Drain, 15. Liquid level pipe, 16. High liquid level sensor, 17. High-high liquid level sensor, 18. Outlet pipe, 19. Transport tank, 20. Threaded hole, 21. Positioning bolt, 22. Detailed Implementation

[0021] 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.

[0022] In the description of this invention, it should be understood that the orientation or positional relationship indicated by terms such as "longitudinal", "lateral", "up", "down", "vertical", "horizontal", "top", and "bottom" is based on the orientation or positional relationship shown in the accompanying drawings and is only for the convenience of describing this invention and simplifying the description, and is not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0023] like Figure 1 , Figure 2 As shown, this embodiment provides a nested structure multi-level monitoring storage device for strongly acidic chromium-containing waste liquid, which is suitable for the safe storage and real-time monitoring of strongly acidic chromium-containing waste liquid in industries such as electroplating and chemical processing. It includes a storage tank body 1, which is composed of an outer tank 1.1 and an inner tank 1.2 with a nested structure. Both the outer tank 1.1 and the inner tank 1.2 are closed structures.

[0024] The inner tub 1.2 is made of corrosion-resistant material. In one embodiment, the inner tub 1.2 is made of 2mm thick PTFE (polytetrafluoroethylene) material, 1.5m high, and 0.8mm in diameter, manufactured using a hot-pressing process. During molding, necessary interfaces are pre-reserved, and the remaining parts are ensured to be seamless to enhance corrosion resistance. The outer tub 1.1 is made of 6mm thick Q345R steel plate, rolled and longitudinally welded using double-sided submerged arc welding (according to JB / T 4709-2018). After welding, it undergoes annealing treatment at 620℃ for 2 hours. The weld is subjected to 100% radiographic testing, achieving Class II qualification (compliant with NB / T 47013-2015). The design pressure is ≥0.6MPa. After welding the necessary interfaces and machining the required holes on the outer tub 1.1, an epoxy resin anti-corrosion coating is sprayed onto the surface.

[0025] The inner tank 1.2 is used to store waste liquid. The inlet 2 of the inner tank 1.2 is connected to the waste liquid discharge pipe 4 (carbon steel lined with PTFE) of the upstream equipment (corrosion machine) through one of the flanged interfaces on the outer tank 1.1. The waste liquid discharge pipe 4 is equipped with at least one waste discharge valve (omitted in the figure). The outlet 15 of the inner tank 1.2 is connected to the outlet pipe 19 (PFA + hose) through one of the flanged interfaces on the outer tank 1.1. The outlet pipe 19 is connected to a valve. The exhaust port 3 of the inner tank 1.2 is connected to the exhaust pipe 5 (PP material) through one of the flanged interfaces on the outer tank 1.1. The exhaust pipe 5 is connected to the waste gas treatment system at the plant end for acidic waste gas treatment, and finally meets the emission standards (compliant with GB / T 16297-1996). The inner tub 1.2 is also connected to a liquid level pipe 16 through other flanged interfaces on the outer tub 1.1. The liquid level pipe 16 is used to display the liquid level of the inner tub 1.2. In order to quickly grasp the liquid level, the liquid level pipe 16 is equipped with a liquid level sensor. The number of liquid level sensors and the height difference are determined according to the actual scenario.

[0026] In this embodiment, the high-level liquid level sensor 17 and the upper-high-level liquid level sensor 18 are respectively installed on the side wall of the outer tank 1.1 at a distance of 30cm and 20cm from the top, to monitor liquid level changes in real time. In one embodiment, both the high-level liquid level sensor 17 and the upper-high-level liquid level sensor 18 are high-frequency ultrasonic liquid level sensors (20Hz sampling frequency), which can monitor sudden changes in liquid level (such as rapid leakage caused by rupture) and situations where the liquid level is too high in real time.

[0027] It should be noted that the inner walls of each interface on the outer tank 1.1 are lined with PTFE, or the corresponding functional ports of the inner tank 1.2 (such as liquid inlet 2, liquid outlet 15, etc.) extend directly to the inner wall as a liner to reduce the contact between the outer tank 1.1 and the waste liquid.

[0028] Below the outer tank 1.1, a drip tray 13 is provided to collect leaked liquid. The drip tray 13 is equipped with at least one leak sensor 14 to monitor the leakage in real time. In one embodiment, the leak sensor 14 is a capacitive leak sensor that detects minute leaks (sensitivity 0.1 mL). Since an external transport tank 20 is required, and the main body of the storage tank 1 needs to avoid direct contact with the ground, in this embodiment, the outer tank 1.1 is mounted on a support 12, thereby raising the height of the outlet pipe 19 to facilitate the connection of the external transport tank 20. The support 12 is located within the drip tray 13, which can completely collect leaked waste liquid.

[0029] In this embodiment, both the liquid level sensor and the leakage sensor 14 are connected to a control system (e.g., the control system of a corrosion machine). When the detection data of the liquid level sensor triggers a set threshold, the control system activates an alarm device and closes the waste discharge valve of the waste liquid discharge pipe 4. For example, when the liquid level reaches the height of the high-level liquid level sensor 17, an alarm is issued to remind the operator; when it reaches the height of the high-level liquid level sensor 18, an alarm is issued to remind the operator and all waste discharge valves are closed. The operator then handles the situation according to the set workflow. Similarly, when the detection data of the leakage sensor 14 triggers a set threshold, the control system activates an alarm device and closes the waste discharge valve of the waste liquid discharge pipe 4. The operator then handles the situation according to the set workflow.

[0030] In actual production, the sensors are calibrated regularly to keep the error within a reasonable range.

[0031] The top of the outer barrel 1.1 is a flanged opening 9. The portion extending upwards from the opening 9 forms a neck 10. The opening 9 is sealed by a flange cover 7, which is fastened to the flange with stainless steel bolts. The sealing surfaces of both are sealed with corrosion-resistant gaskets 8. An exhaust hood 6 is installed above the opening 9. This exhaust hood 6 is connected to a waste gas treatment system. When activated, the exhaust hood 6 draws in and discharges waste gas caused by leakage, sending it to the waste gas treatment system for processing.

[0032] The bottom of the inner tub 1.2 is provided with a support component 11 to prevent the bottom of the inner tub 1.2 from directly contacting the outer tub 1.1. In one embodiment, the support component 11 is a support ring made of PTFE material.

[0033] A small gap exists between the inner tub 1.2 and the outer tub 1.1. To limit the movement of the inner tub 1.2 within the outer tub 1.1, threaded holes 21 are provided at the neck 10, top, body, and bottom of the outer tub 1.1. Positioning bolts 22 (sealed connection) are fitted into these threaded holes 21. The inner ends of the positioning bolts 22 at the neck 10, top, and body abut against the corresponding outer wall of the inner tub 1.2, while the positioning bolt 22 at the bottom abuts against the support member 11. Force is applied to the inner tub 1.2 through the support member 11. Adjusting the screw-in length of the positioning bolts 22 adjusts the pressure on the inner tub 1.2, thus limiting its movement. Figure 2 The diagram shows the installation structure of the outer barrel, inner barrel, and positioning bolts in the barrel body section; the other parts are similar.

[0034] The following are the actual application and test data of this embodiment: Corrosion resistance test According to ASTM G48 standard, the corrosion rate of PTFE inner tank after immersion in waste liquid for 720 hours is <0.01mm / year, while the corrosion rate of 304 stainless steel control group is 4.2mm / year; Strength verification The steel plate is made of Q345R steel (6mm thick), which is rolled and welded and then annealed to relieve stress. The water pressure test pressure is 0.9MPa. In actual use, the maximum stress under full load is 0.12MPa, which is lower than the allowable stress of Q345R (189MPa, GB 150.2-2011). Leakage Detection Test Simulated leakage conditions (artificial puncture of the inner drum): the sensor triggers an alarm within 10 seconds, the waste discharge valve closes, and the leakage amount is <0.5L; Overall comparison Under the same design pressure, the wall thickness of Q345R can be reduced by 25% compared to Q235 (the original 8mm Q235 is replaced by 6mm Q345R), resulting in a 15% reduction in weight per tank. Q345R material costs 79.2% less than 304 stainless steel, and its welding process is mature (referencing JB / T 4709-2018). Material Yield strength (MPa) Recommended wall thickness (pH < 1) Cost (RMB / ton) Q235 235 8mm 4500 Q345R 345 6mm 5200 304 stainless steel 205 PTFE lining required 25000 Performance Comparison Performance indicators Traditional 304 stainless steel solution This embodiment's solution Corrosion resistance life 3 months ≥10 years Leakage Response Practice ≤30 seconds ≤10 seconds Comprehensive cost <![CDATA[￥25000 / m 3 ]]> <![CDATA[￥12000 / m 3 ]]> Leakage response comparison Testing Plan Conventional single sensor This embodiment's solution Response time 18 seconds 10 seconds False alarm rate 16% 12% Data source: Refer to the test method of HJ 799-2016.

[0035] The above description is merely a preferred embodiment of the present invention. For those skilled in the art, the present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A multi-level monitoring device for storing strongly acidic chromium-containing waste liquid with a nested structure, characterized in that: The tank includes a main body (1), which is composed of an outer tank (1.1) and an inner tank (1.2) with a nested structure. The inner tank (1.2) is made of corrosion-resistant material, and both the outer tank (1.1) and the inner tank (1.2) are closed structures. The inner tank (1.2) is connected to the following via several interfaces on the outer tank (1.1): a waste liquid discharge pipe (4) of the upper equipment, an outlet pipe (19) for connecting to an external transport tank (20), an exhaust pipe (5) for discharging waste gas, and a level pipe (16) for displaying the liquid level of the inner tank (1.2); the level pipe (16) is equipped with at least one level sensor. The outer barrel (1.1) is provided with a liquid receiving tray (13) for receiving leakage, and the liquid receiving tray (13) is provided with at least one leakage sensor (14). The liquid level sensor and the leakage sensor (14) are both connected to the control system. When the detection data of the liquid level sensor or the leakage sensor (14) triggers the set threshold, the control system activates the alarm device and closes the waste discharge valve of the waste liquid discharge pipe (4).

2. The nested structure multi-level monitoring storage device for strongly acidic chromium-containing waste liquid according to claim 1, characterized in that, The outer barrel (1.1) is mounted on the bracket (12), thereby raising the height of the outlet pipe (19) to facilitate the connection of the external transport barrel (20).

3. The nested structure multi-level monitoring storage device for strongly acidic chromium-containing waste liquid according to claim 1, characterized in that, The outer barrel (1.1) is made of Q345R steel plate.

4. The nested structure multi-level monitoring storage device for strongly acidic chromium-containing waste liquid according to claim 1, characterized in that, The inner barrel (1.2) is made of polytetrafluoroethylene.

5. The nested structure multi-level monitoring storage device for strongly acidic chromium-containing waste liquid according to claim 1, characterized in that, The top of the outer barrel (1.1) is a barrel opening (9) with a flange. The barrel opening (9) is closed by a flange cover (7). The sealing surfaces of the flange cover (7) and the flange are sealed with corrosion-resistant gaskets (8).

6. The nested structure multi-level monitoring storage device for strongly acidic chromium-containing waste liquid according to claim 5, characterized in that, An exhaust hood (6) is provided above the barrel opening (9), and the exhaust hood (6) is connected to the waste gas treatment system.

7. A nested structure multi-level monitoring storage device for strongly acidic chromium-containing waste liquid according to claim 1, characterized in that, The exhaust pipe (5) is connected to the exhaust gas treatment system.

8. A nested structure multi-level monitoring storage device for strongly acidic chromium-containing waste liquid according to any one of claims 1-7, characterized in that, The bottom of the inner tub (1.2) is provided with a support component (11) to prevent the bottom of the inner tub (1.2) from directly contacting the outer tub (1.1).

9. A nested structure multi-level monitoring storage device for strongly acidic chromium-containing waste liquid according to claim 8, characterized in that, At least one of the following parts of the outer barrel (1.1): the barrel neck (10), the barrel top, the barrel body, and the barrel bottom, is provided with positioning bolts (22): the inner ends of the positioning bolts (22) of the barrel neck (10), the barrel top, and the barrel body abut against the outer wall of the corresponding part of the inner barrel (1.2), and the positioning bolts (22) of the barrel bottom abut against the support member (11).

10. A nested structure multi-level monitoring device for storing strongly acidic chromium-containing waste liquid according to claim 8, characterized in that, The support component (11) is a support ring made of polytetrafluoroethylene.

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