An oil sludge pit supernatant collecting device and method

Abstract

The application provides an oil-containing sludge pool supernatant collecting device and method, which comprises a floating liquid collector, a liquid level detector, a water pump and an electric control cabinet, the liquid level detector is used for detecting the submergence depth of the floating liquid collector, the liquid level detector and the water pump are electrically connected with the electric control cabinet, the electric control cabinet is used for receiving the submergence depth data of the liquid level detector in real time, and sends a signal to the water pump according to the submergence depth data to control the start and stop of the water pump. The floating liquid collector is installed in the sludge pool and floats up and down with the liquid level, the submergence depth of the floating liquid collector is detected by the liquid level detector, the electric control cabinet sends a signal according to the submergence depth to control the start and stop of the water pump, and the supernatant is pumped out. The application can also be used for collecting floating oil in the oil removal tank, the oil separation tank and the sewage tank.

Description

Technical Field

[0001] This invention belongs to the field of oilfield wastewater treatment technology, specifically relating to a device and method for collecting supernatant from oily sludge ponds. Background Technology

[0002] Crude oil extraction produces a large amount of produced water, which is typically treated and then reinjected into the formation to replenish its energy. Produced water contains petroleum hydrocarbons, mineral impurities, and organic matter, and its treatment generates a significant amount of oily sludge.

[0003] Currently, the treatment of oily sludge involves setting up sludge tanks within water treatment plants to receive oily sludge and various types of wastewater generated within the plant. After sedimentation and concentration, the supernatant in the tanks flows into a wastewater tank, while the bottom sludge is periodically cleaned and transported off-site. The timely and effective collection and discharge of the supernatant directly affects the sludge concentration effect. There are two methods for supernatant collection: fixed collection pipes and floating collection devices. The former involves installing collection pipes at different heights on the sludge tank walls. Before collection, the valve of the corresponding collection pipe at the supernatant-sludge interface is opened. The latter uses floating collectors or decanters that float on the liquid surface for collection.

[0004] However, both of the above methods require testing the interface between the supernatant and sludge, as well as the thickness of the supernatant, before collection. Current methods for detecting the sludge-water interface mainly rely on sampling observation or ultrasonic sludge level gauges (or sludge-water interface meters). Sampling observation is labor-intensive, highly dependent on operator methods, cannot provide continuous measurement, and cannot accurately contribute to control. Ultrasonic sludge level gauges, on the other hand, have significant measurement errors. The State Intellectual Property Office has published a patent (CN2316014Y) entitled "A Device for Discharging Supernatant After Mixed Liquor Settling." This device uses a sludge-water interface meter to detect the thickness of the supernatant layer, transmitting the data to a control instrument. This drives a motor, which in turn rotates a sprocket and transmission chain, ultimately rotating the main drainage pipe to begin drainage. However, the meter probe needs to be immersed in the liquid. Because the liquid composition in sludge tanks is complex, with high levels of impurities such as asphalt, wax, and colloids, sludge easily adheres to the probe, causing measurement errors. Furthermore, the high cost of ultrasonic level gauges also hinders their widespread application. Summary of the Invention

[0005] The purpose of this invention is to provide a device for collecting supernatant from oily sludge ponds, overcoming the aforementioned technical problems in the prior art.

[0006] Another objective of this invention is to provide a method for collecting supernatant from oily sludge ponds, which can automatically collect supernatant based on its thickness, with accurate detection and control.

[0007] Therefore, the technical solution provided by the present invention is as follows: A device for collecting supernatant from an oily sludge pond includes a floating liquid collector, a level gauge, a water pump, and an electrical control cabinet. The level gauge is used to detect the submersion depth of the floating liquid collector. The level gauge and the water pump are both electrically connected to the electrical control cabinet. The electrical control cabinet is used to receive the submersion depth data from the level gauge in real time and send a signal to the water pump to control its start and stop based on the submersion depth data. The floating liquid collector includes an irregularly shaped floating chamber, a connecting support, and a disc-shaped liquid inlet. There are multiple irregularly shaped floating chambers, which are arranged into a regular polygon by the connecting support. The disc-shaped liquid inlet is located at the center of the regular polygon, and all the irregularly shaped floating chambers are connected to the disc-shaped liquid inlet by the connecting support.

[0008] The irregularly shaped floating chamber is a frustum-shaped structure with a smaller top and a larger bottom. The interior of the irregularly shaped floating chamber is hollow, and an injection port is provided at the top of the irregularly shaped floating chamber.

[0009] The disc-shaped liquid inlet includes a horizontal disc, a liquid outlet pipe, and multiple liquid inlets. The liquid outlet pipe is located on the lower end face of the horizontal disc. The center of the horizontal disc is a connecting space. The multiple liquid inlets are horizontally arranged and evenly distributed along the circumference of the horizontal disc. The multiple liquid inlets are separated by partitions and are all connected to the connecting space. The liquid outlet pipe is connected to the connecting space. The water pump is connected to the liquid outlet pipe through a flexible hose.

[0010] It also includes a guide support, which is located within a regular polygon and whose bottom is fixed to the sludge tank.

[0011] The top of the disc-shaped suction port is provided with an instrument mounting tube, the liquid level detector is installed inside the instrument mounting tube, the instrument mounting tube has multiple through holes, and the instrument mounting tube is covered with a filter screen.

[0012] There are three irregularly shaped floating chambers. The connecting support connects the disc-shaped liquid intake port and the three irregularly shaped floating chambers into a whole. The disc-shaped liquid intake port is located below the liquid surface.

[0013] A method for collecting supernatant from an oily sludge tank involves using an oily sludge tank supernatant collection device. Oily sludge water is discharged into the sludge tank, and a floating liquid collector floats with the liquid level. A liquid level detector monitors the submersion depth of the disc-shaped suction port of the floating liquid collector in real time and sends the data to the electrical control cabinet. When the submersion depth of the disc-shaped suction port reaches the set value H1, the electrical control cabinet sends a signal to the water pump, which starts and extracts the supernatant. As the water pump operates, the supernatant gradually decreases, the liquid level drops, and the floating liquid collector descends with the liquid level. When the submersion depth of the disc-shaped suction port decreases to H2, the electrical control cabinet sends a signal to the water pump, and the water pump stops.

[0014] In the initial stage of oily sludge wastewater discharge into the sludge tank, the tank contains oily sludge wastewater with a density between that of the supernatant and the sludge. The floating liquid collector generates significant buoyancy, and the disc-shaped suction port is submerged at a shallow depth. At this stage, the submersion depth is greater than H2 and less than [the required depth for H2].

[0015] The beneficial effects of this invention are: The oily sludge tank supernatant collection device provided by this invention involves installing a floating collector inside the sludge tank, which floats up and down with the liquid level. A level gauge detects the submersion depth of the floating collector, and the electrical control cabinet sends a signal based on the submersion depth to control the water pump to start and stop, thereby extracting the supernatant. It can also be used for collecting floating oil in oil removal tanks, grease traps, and sewage tanks.

[0016] Compared to existing upward or downward suction methods, the floating liquid collector in the oily sludge pond supernatant collection device has a disc-shaped suction port. The main body of the disc-shaped suction port is a horizontal disc, which is divided into multiple horizontal inlet holes by a partition. The disc-shaped suction port uses a horizontal direction to uniformly introduce liquid, which will not suck in the upper air to generate swirling flow, nor will it suck in the bottom sludge.

[0017] This invention addresses the issue of unclear interfaces between the supernatant and sludge layers, where significant differences in solids content lead to different densities. For floating liquid collectors with constant weight, achieving the same buoyancy requires displacing a larger volume of liquid in the supernatant zone (depth of immersion is greater, H1) and a smaller volume of liquid in the sludge zone (depth of immersion is less, H2). This method indirectly determines the sludge-water interface position by detecting the immersion depth of the disc-shaped suction port, rather than directly detecting the interface, resulting in more accurate detection. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of one embodiment of the present invention; Figure 2 This is a front view of one implementation of a floating liquid receiver; Figure 3 This is a top view of one implementation of a floating liquid collector; Figure 4 This is a front view of the disc-shaped suction port; Figure 5 This is a top view of the disc-shaped suction port; Figure 6 This is a schematic diagram of liquid level control. Figure 1 ; Figure 7 This is a schematic diagram of liquid level control. Figure 2 .

[0019] ​In the diagram: 1. Floating liquid collector; 2. Water pump; 3. Electrical control cabinet; 4. Liquid level gauge; 5. Hoses; 6. Sludge tank; 7. Guide support; 8. Disc-shaped suction port; 9. Irregularly shaped floating tank; 10. Instrument mounting pipe; 11. Injection port; 12. Discharge pipe; 13. Baffle plate; 14. Connecting support; 15. Filter screen; 16. Through hole. Detailed Implementation

[0020] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0021] Exemplary embodiments of the present invention will now be described with reference to the accompanying drawings. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein. These embodiments are provided to fully and completely disclose the invention and to fully convey its scope to those skilled in the art. The terminology used in the exemplary embodiments illustrated in the drawings is not intended to limit the invention. In the drawings, the same units / elements are referred to by the same reference numerals.

[0022] Unless otherwise stated, the terms used herein (including technical terms) have their common meaning as understood by one of ordinary skill in the art. Furthermore, it is understood that terms defined in commonly used dictionaries should be understood to have a meaning consistent with the context of their relevant field, and not to be interpreted as having an idealized or overly formal meaning.

[0023] Example 1 This embodiment provides a device for collecting supernatant from an oily sludge pond, such as... Figure 1 As shown, the device includes a floating liquid collector 1, a liquid level gauge 4, a water pump 2, and an electrical control cabinet 3. The liquid level gauge 4 is used to detect the submersion depth of the floating liquid collector 1. The liquid level gauge 4 and the water pump 2 are both electrically connected to the electrical control cabinet 3. The electrical control cabinet 3 is used to receive the submersion depth data from the liquid level gauge 4 in real time and send a signal to the water pump 2 to control the start and stop of the water pump 2 based on the submersion depth data. The oily sludge tank supernatant collection device provided by this invention can automatically collect supernatant based on its thickness in the sludge tank 6. A floating collector 1 is installed inside the sludge tank 6, floating up and down with the liquid level. A level gauge 4 detects the submersion depth of the floating collector 1. The electrical control cabinet 3 sends a signal based on the submersion depth to control the water pump 2 to start and stop, thus extracting the supernatant. This invention can also be used for collecting floating oil in oil removal tanks, grease traps, and sewage tanks.

[0024] Example 2 Based on Example 1, this example provides a supernatant collection device for oily sludge ponds. The floating liquid collector 1 includes an irregularly shaped floating chamber 9, a connecting support 14, and a disc-shaped suction port 8. There are multiple irregularly shaped floating chambers 9, which are arranged into a regular polygon by the connecting support 14. The disc-shaped suction port 8 is located at the center of the regular polygon, and all the irregularly shaped floating chambers 9 are connected to the disc-shaped suction port 8 by the connecting support 14.

[0025] like Figure 2 As shown, the connecting support 14 connects and fixes the disc-shaped liquid intake port 8 and multiple irregularly shaped floating tanks 9 into a whole. The disc-shaped liquid intake port 8 floats at a certain depth below the liquid surface under the support of the irregularly shaped floating tanks 9.

[0026] Example 3 Based on Example 1, this example provides a device for collecting supernatant from an oily sludge pond. The irregularly shaped floating chamber 9 is a frustum shape with a smaller top and a larger bottom. The interior of the irregularly shaped floating chamber 9 is a cavity, and an injection port 11 is provided at the top of the irregularly shaped floating chamber 9.

[0027] Due to the density of the supernatant (1g / cm³) 3 ) and the density of the concentrated sludge (approximately 1.1 g / cm³) 3 The difference is small, and the use of irregularly shaped floating silos can effectively increase the variation range of submersion depth under different densities and improve the reliability of instrument detection. For example, Figure 2 As shown, the irregularly shaped floating tank 9 is composed of two stacked cylinders, with the cylinders having a smaller diameter at the top and a larger diameter at the bottom, and a hollow, interconnected interior. The irregularly shaped floating tank 9 is equipped with a liquid injection port 11, through which liquid can be injected into the floating tank 9 to adjust the counterweight.

[0028] Example 4 Based on Example 1, this example provides a device for collecting supernatant from an oily sludge pond, such as... Figure 4 As shown, the disc-shaped liquid inlet 8 includes a horizontal disc, a liquid outlet pipe 12, and multiple liquid inlets. The liquid outlet pipe 12 is located on the lower end face of the horizontal disc. The center of the horizontal disc is a communicating space. The multiple liquid inlets are horizontally arranged and evenly distributed along the circumference of the horizontal disc. The multiple liquid inlets are separated by a partition 13 and are all connected to the communicating space. The liquid outlet pipe 12 is connected to the communicating space. The water pump 2 is connected to the liquid outlet pipe 12 through a flexible hose 5.

[0029] Compared to traditional upward or downward suction methods, the disc-shaped suction port 8 has a horizontal disc-shaped main body, which is divided into multiple horizontal inlet holes by the partition plate 13 (e.g., Figure 5 As shown), the disc-shaped liquid inlet 8 uses a horizontal direction for uniform liquid inlet (as shown). Figure 4As shown, it will not draw in upper air to create a vortex, nor will it draw in bottom sludge. The outlet pipe 12 of the disc-shaped suction port 8 is installed vertically downwards from the horizontal disc and is connected to the inlet of the water pump 2 via a hose 5.

[0030] Example 5 Based on Embodiment 1, this embodiment provides a supernatant collection device for oily sludge ponds, which also includes a guide support 7. The guide support 7 is disposed within a regular polygon, and the bottom of the guide support 7 is fixed to the sludge pond 6.

[0031] like Figure 1 As shown, the guide bracket 7 is installed between the floating liquid collector connecting support 14 and the bottom is fixed to the sludge tank 6 to ensure that the floating liquid collector 1 floats up and down along the guide bracket 7 with the water level change and will not drift with the water flow.

[0032] Example 6 Based on Example 1, this example provides a supernatant collection device for oily sludge ponds. The top of the disc-shaped suction port 8 is provided with an instrument mounting pipe 10. The liquid level detector 4 is installed inside the instrument mounting pipe 10. The instrument mounting pipe 10 has multiple through holes 16 and is covered with a filter screen 15.

[0033] like Figure 1 As shown, the level gauge 4 is installed inside the instrument mounting tube 10 above the disc-shaped suction port 8, detecting the submersion depth of the disc-shaped suction port 8 and transmitting the signal to the control cabinet 3. The instrument mounting tube 10 has multiple through holes 16 on its side wall and is covered with a filter screen 15 to block water debris and prevent it from affecting the detection accuracy. In this embodiment, the level gauge 4 is a low-cost and commonly used float level gauge.

[0034] Example 7 Based on Example 1, this example provides a device for collecting supernatant from an oily sludge pond, such as... Figure 3 As shown, there are three irregularly shaped floating pods 9. The connecting support 14 connects the disc-shaped liquid intake port 8 and the three irregularly shaped floating pods 9 into a whole. The disc-shaped liquid intake port 8 is located below the liquid surface.

[0035] There are three irregularly shaped floating chambers 9, evenly distributed around the disc-shaped liquid suction device to ensure the balance of the disc-shaped liquid suction port 8. Each irregularly shaped floating chamber 9 is equipped with a liquid injection port 11. Liquid can be injected into the irregularly shaped floating chamber 9 through the liquid injection port 11 to adjust the counterweight.

[0036] The irregularly shaped floating hopper 9 is a hollow structure. During the initial installation of the floating liquid collector 1, the submersion depth of the disc-shaped suction port 8 should be set according to the density changes in the supernatant and sludge zones. In the supernatant zone, the liquid density is lower, the buoyancy is smaller, and the submersion depth is greater, designated as H1. At the boundary between the supernatant and sludge zones, the liquid density is higher, the buoyancy is greater, and the submersion depth is smaller, designated as H2. Based on this, the signal limits of the detection device 4 should be set: H1 is the pump start value, and H2 is the pump stop value. For example... Figure 6 , Figure 7 .

[0037] Example 8 This embodiment provides a method for collecting supernatant from an oily sludge tank. An oily sludge tank supernatant collection device is used. The oily sludge water is discharged into the sludge tank 6. The floating liquid collector 1 floats with the liquid level. The liquid level detector 4 detects the submersion depth of the disc-shaped suction port 8 of the floating liquid collector 1 in real time and sends the data to the electrical control cabinet 3. When the submersion depth of the disc-shaped suction port 8 reaches the set value H1, the electrical control cabinet 3 sends a signal to the water pump 2, and the water pump 2 starts to extract the supernatant. As water pump 2 operates, the supernatant gradually decreases, the liquid level drops, and the floating liquid collector 1 descends with the liquid level. When the submersion depth of the disc-shaped suction port 8 drops to H2, the electrical control cabinet 3 sends a signal to water pump 2, and water pump 2 stops.

[0038] Principle of this invention: Given the unclear interface between the supernatant and sludge layers, but with a significant difference in solids content (resulting in different densities), for the floating liquid collector 1 with a constant weight, a larger volume of liquid needs to be displaced in the supernatant zone to achieve the same buoyancy; that is, a greater submersion depth (H1) is required. Figure 6 As shown; in the sludge zone, a small volume of liquid needs to be drained, and the submersion depth is shallow (H2), such as Figure 7 As shown in the figure. This method indirectly determines the position of the mud-water interface by detecting the submersion depth of the disc-shaped suction port 8, rather than directly detecting the mud-water interface, thus improving the detection accuracy.

[0039] Example 9 Based on Example 8, this example provides a method for collecting supernatant from an oily sludge tank. In the initial stage of discharge of oily sludge water into the sludge tank 6, the sludge tank 6 contains oily sludge water with a density between that of the supernatant and the sludge. The floating liquid collector 1 generates a large buoyancy, and the disc-shaped suction port 8 is submerged at a shallow depth. At this time, the submersion depth is greater than H2 and less than H2.

[0040] ​During operation: When the oily sludge water generated by the treatment plant is discharged into the sludge tank 6, the floating liquid collector 1 floats with the water flow. At this time, the tank contains oily sludge water with a density between that of the supernatant and the sludge. The buoyancy generated by the irregularly shaped floating chamber 9 is large, and the submersion depth of the disc-shaped liquid suction port 8 is shallow. At this time, the submersion depth of the disc-shaped liquid suction port 8 is > H2.

[0041] The above examples are merely illustrative of the present invention and do not constitute a limitation on the scope of protection of the present invention. All designs that are the same as or similar to the present invention are within the scope of protection of the present invention.​

Claims

1. A device for collecting supernatant from an oily sludge pond, characterized in that, It includes a floating liquid receiver, a liquid level gauge, a water pump, and an electrical control cabinet, wherein the liquid level gauge and the water pump are both electrically connected to the electrical control cabinet. The floating liquid collector includes three irregularly shaped floating chambers, a connecting support, and a disc-shaped liquid inlet. The three irregularly shaped floating chambers form an equilateral triangle through the connecting support. The disc-shaped liquid inlet is located at the center of the equilateral triangle and is positioned below the liquid surface. All three irregularly shaped floating chambers are connected to the disc-shaped liquid inlet through the connecting support. Each of the irregularly shaped floating pods is a hollow structure. The shape of the irregularly shaped floating pod is composed of two cylinders that are stacked on top of each other and connected internally. The diameter of the upper cylinder is smaller than the diameter of the lower cylinder. The top of the irregularly shaped floating pod is provided with a liquid injection port for injecting liquid into the irregularly shaped floating pod to adjust the counterweight. The disc-shaped liquid inlet includes a horizontal disc, a liquid outlet pipe, and multiple liquid inlets. The liquid outlet pipe is installed downwards perpendicular to the horizontal disc. A communicating space is provided at the center of the horizontal disc. The multiple liquid inlets are horizontally arranged and evenly distributed along the circumference of the horizontal disc. Adjacent liquid inlets are separated by partitions. Each liquid inlet is connected to the communicating space. The liquid outlet pipe is connected to the communicating space. The water pump is connected to the liquid outlet pipe through a flexible hose. The top of the disc-shaped suction port is provided with an instrument mounting tube. The side wall of the instrument mounting tube has multiple through holes and is covered with a filter screen. The liquid level detector is installed inside the instrument mounting tube and is used to detect the submersion depth of the disc-shaped suction port relative to the liquid surface. The injection volume in the irregular floating tank is adjusted as follows: when the disc-shaped suction port is in the supernatant zone with lower density, the submersion depth can reach the pump start setting value H1; when the disc-shaped suction port descends to the critical zone between the supernatant and sludge with higher density, the submersion depth is reduced to the pump stop setting value H2, where H1 is greater than H2. The electrical control cabinet is used to receive the flooding depth data detected by the liquid level detector in real time, and to control the water pump to start when the flooding depth reaches H1, and to control the water pump to stop when the flooding depth decreases to H2.

2. The oily sludge tank supernatant collection device according to claim 1, characterized in that, It also includes a guide support, which is set inside the equilateral triangle. The bottom of the guide support is fixed to the sludge tank so that the floating liquid collector floats up and down along the guide support as the liquid level in the tank changes.

3. A device for collecting supernatant from an oily sludge pond according to claim 1 or 2, characterized in that, The level sensor is a float level sensor.

4. A method for collecting supernatant from an oily sludge pond, comprising the oily sludge pond supernatant collection device as described in any one of claims 1-3, characterized in that, include: Oily sludge water is discharged into the sludge tank, and the floating liquid collector floats up with the liquid level in the tank. In the initial stage of discharge, the density of the liquid in the sludge tank is between that of the supernatant and the sludge. The submersion depth of the disc-shaped suction port is greater than H2 and less than H1, and the water pump remains stopped. The oily sludge water is allowed to settle and concentrate naturally in the sludge tank. The liquid in the upper part of the tank gradually clarifies into a supernatant with a lower density. The submersion depth of the disc-shaped suction port increases accordingly. When the submersion depth reaches H1, the electrical control cabinet controls the water pump to start and extract the supernatant. As the supernatant is extracted, the liquid level in the tank decreases, and the floating liquid collector descends with the liquid level. When the disc-shaped suction port descends to the critical zone between the supernatant and the sludge, the submersion depth of the disc-shaped suction port decreases due to the increased liquid density in this area. When the submersion depth decreases to H2, the electrical control cabinet controls the water pump to stop.

5. The method for collecting supernatant from an oily sludge pond according to claim 4, characterized in that, When the floating liquid collector is installed for the first time, liquid is injected into the irregular floating tank through the injection port on the top of each irregular floating tank to adjust the counterweight. H1 and H2 are set according to the density changes of the supernatant zone and the sludge zone. H1 is set as the pump start value and H2 is set as the pump stop value.

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