Oil-containing sewage pretreatment deoiling device

Abstract

The utility model belongs to the technical field of sewage treatment, and particularly relates to a pretreatment and oil removal device for oily sewage. Comprising an inspection filter well, an oil separation tank, a sewage adjusting tank, a hydrocyclone coalescence separator and a high-efficiency closed air flotation machine which are communicated in sequence, and a water outlet of the high-efficiency closed air flotation machine is connected to a biochemical treatment system through a pipeline; a floating oil collector is arranged at the top of the oil separation tank and is connected to the dirty oil tank through a floating oil discharge pipe; a light phase outlet in the top of the rotary liquid coalescence separator is connected to the dirty oil tank; a heavy phase outlet in the bottom of the cyclone liquid coalescence separator and a sludge discharge port of the efficient closed air flotation machine are connected to a sludge tank; a bottom outlet of the sludge tank is connected to a stacked screw dehydrator through a sludge pump, and a water outlet of the stacked screw dehydrator is connected to a biochemical treatment system. Through the synergistic effect of all the devices, oil, suspended solids and part of refractory organics in the oily sewage can be comprehensively and efficiently removed, the biodegradability of the sewage is improved, and extremely favorable conditions are created for the subsequent biochemical treatment process.

Description

Technical Field

[0001] The utility model belongs to the technical field of sewage treatment, and particularly relates to an oil removal device for the pretreatment of oily sewage. Background Art

[0002] With the acceleration of the industrialization process, the treatment of oily sewage has become an indispensable part of the environmental protection field. Especially in high-end petroleum processing industries such as lubricating base oil hydrocracking units, a large amount of oily sewage generated during the production process has extremely complex components, containing not only high concentrations of oils, suspended solids, but also a large amount of ammonia nitrogen and refractory organic pollutants. If these pollutants enter the biochemical treatment process directly without effective pretreatment, a series of serious problems will occur.

[0003] First of all, the high concentrations of oils and suspended solids in the oily sewage will seriously interfere with the normal operation of the biochemical treatment system. The oil substances will cover the surface of the biofilm, hindering the transmission of oxygen and nutrients, resulting in a decrease in microbial activity and a reduction in treatment efficiency. At the same time, the toxic and harmful substances in the suspended solids will also have a toxic effect on the microorganisms, further affecting the biochemical treatment effect.

[0004] Secondly, the high content of refractory organic pollutants and poor biodegradability in the oily sewage make it difficult for the biochemical treatment system to effectively remove these pollutants. Traditional biochemical treatment processes often show problems such as low treatment efficiency and difficult-to-meet effluent water quality when treating such sewage. In the long-term operation, not only will the treatment cost increase, but it may also cause secondary pollution to the surrounding environment.

[0005] In addition, the oily sewage may also contain toxic and harmful substances such as sulfides and phenols, which have great toxicity to the microorganisms in the biochemical treatment system, will seriously inhibit the growth and metabolic activities of the microorganisms, and even lead to the collapse of the system.

[0006] Therefore, for the oily sewage generated in high-end petroleum processing industries such as lubricating base oil hydrocracking units, it is particularly important to carry out necessary pretreatment. Through pretreatment, the oils, suspended solids and some refractory organic pollutants in the sewage can be effectively removed, the biodegradability of the sewage can be improved, and favorable conditions can be created for the subsequent biochemical treatment process. Content of the Utility Model

[0007] According to the deficiencies in the above prior art, the purpose of the present utility model is to provide an oil removal device for the pretreatment of oily sewage. Through the coordinated action of devices such as an inspection and filtration well, an oil separation tank, a hydrocyclone coalescer, and a high-efficiency airtight flotation machine, it can comprehensively and efficiently remove the oils, suspended solids and some refractory organic pollutants in the oily sewage, improve the biodegradability of the sewage, and create extremely favorable conditions for the subsequent biochemical treatment process.

[0008] The utility model is realized by adopting the following technical solutions:

[0009] The oil-containing sewage pretreatment and oil removal device includes an inspection and filtration well, an oil separation tank, a sewage regulation tank, a hydrocyclone coalescer, and a high-efficiency closed air flotation machine that are sequentially connected through process pipelines. The water outlet of the high-efficiency closed air flotation machine is connected to the biochemical treatment system through a pipeline;

[0010] A floating oil collector is provided at the top of the oil separation tank and is connected to an oil sludge tank through a floating oil discharge pipe. The light-phase outlet at the top of the hydrocyclone coalescer is connected to the oil sludge tank through an oil-phase recovery pipe;

[0011] The heavy-phase outlet at the bottom of the hydrocyclone coalescer and the sludge discharge port of the high-efficiency closed air flotation machine are connected to a sludge tank through a slag discharge pipeline; the outlet at the bottom of the sludge tank is connected to a spiral press through a sludge pump, and the water outlet of the spiral press is connected to the biochemical treatment system;

[0012] The sewage regulation tank is connected to the feed inlet of the hydrocyclone coalescer after converging with the purified water outlet pipeline of the acidic water stripping unit through a first self-priming pump; the bottom of the oil separation tank is connected to the sewage regulation tank through a siphon;

[0013] It further includes an emergency water tank, and the outlet of the emergency water tank is connected to the sewage regulation tank through a second self-priming pump.

[0014] A demulsifier dosing pipeline and a flocculant dosing pipeline are connected to the top of the hydrocyclone coalescer.

[0015] A three-stage stepped grille is provided in the inspection and filtration well, including: an upper coarse grille, a middle fine grille, and a lower screen.

[0016] An electric tracing heat preservation pipe is provided between the floating oil collector and the oil sludge tank.

[0017] A mud cake conveyor belt is provided below the mud outlet of the spiral press.

[0018] A biological deodorization device is provided at the top of the sludge tank.

[0019] The working principle of the oil-containing sewage pretreatment and oil removal device is as follows:

[0020] The oil-containing sewage first enters the inspection and filtration well, and the three-stage stepped grille (upper coarse grille, middle fine grille, lower screen) provided in the well intercepts large-particle suspended solids, fibers, and fine impurities step by step. The inspection and filtration well needs to be inspected and cleaned regularly to ensure its unobstructedness.

[0021] The filtered sewage enters the oil separation tank through the process pipeline. The floating oil on the surface is continuously scraped off by the floating oil collector. The floating oil flows by gravity through the electric tracing heat preservation pipe (maintaining a temperature of 40 - 50 °C) to the waste oil tank, avoiding the blockage caused by the solidification of the oil layer. The sewage without floating oil at the bottom of the oil separation tank is transported to the sewage regulation tank through a siphon.

[0022] The sewage entering the sewage regulation tank is homogenized and regulated in terms of water volume and quality here to stabilize the influent conditions for the subsequent treatment process. At the same time, the purified water (i.e., process wastewater) from the acidic water stripping unit is combined with the sewage in the sewage regulation tank through the first self-priming pump. The combined sewage is lifted by the self-priming pump and enters the hydrocyclone coalescer for further treatment.

[0023] After the sewage enters the hydrocyclone coalescer, the centrifugal inertial force generated by the hydraulic cyclone is utilized to achieve the three-phase separation of oil, water, and solid suspended matter. At the same time, a coalescing element for coarse oil droplets is installed inside the hydrocyclone coalescer, which can capture and polymerize oil droplets larger than 25 μm in water into large oil droplets for separation from water. The separated light oil (i.e., waste oil) enters the waste oil tank through the top light phase outlet and the oil phase recovery pipe; the separated oily sludge is discharged to the sludge tank through the bottom heavy phase outlet. The demulsifier dosing pipeline and the flocculant dosing pipeline at the top of the hydrocyclone coalescer form a jet mixing with the tangential feed pipe through the annular dosing pipe to enhance the demulsification and flocculation effects.

[0024] The effluent from the hydrocyclone coalescer enters the high-efficiency closed air flotation machine. The dissolved air water releases microbubbles (with a particle size of 10 - 20 μm) that adhere to the residual oil droplets and suspended matter. The floating scum is collected by the rotating sludge scraper and discharged into the sludge tank through the slag discharge pipeline. The purified sewage then flows out through the outlet and enters the biochemical treatment system for further treatment.

[0025] The sludge tank receives the floating scum and sludge from the hydrocyclone coalescer and the high-efficiency closed air flotation machine, and is transported to the spiral press filter for dehydration treatment through a sludge pump. The spiral press filter uses the principle of spiral extrusion to squeeze out the water in the sludge to form a sludge cake, and the sludge cake is transported out through the sludge cake conveyor belt for subsequent disposal. At the same time, to reduce the odor pollution during the sludge treatment process, a biological deodorization device is installed at the top of the sludge tank, and the malodorous gases such as hydrogen sulfide and ammonia are degraded by microorganisms to achieve odor control.

[0026] In the event of an accident, the accident wastewater enters the plant accident water tank through the cofferdam. The wastewater in the accident water tank is lifted to the sewage regulation tank for treatment through the second self-priming pump to ensure the timely and effective treatment and disposal of the accident wastewater. The oil removal device for the pretreatment of oily sewage realizes the rapid and efficient pretreatment of oily sewage through the close connection and coordinated operation between various devices, providing a strong guarantee for the subsequent biochemical treatment process.

[0027] Compared with the prior art, the beneficial effects of the present utility model are as follows:

[0028] The oil removal device for the pretreatment of oily sewage described in the utility model realizes the efficient pretreatment of oily sewage through a multi-stage collaborative treatment process, significantly improving the pollutant removal efficiency and the operation stability of the system. First, a stepped treatment system composed of an inspection and filtration well, an oil separation tank, a hydrocyclone coalescer, and a high-efficiency air flotation machine intercepts oils, suspended solids, and refractory organic matters step by step, greatly reducing the subsequent biochemical treatment load and solving problems such as oil film coverage and microbial toxicity inhibition in traditional processes. Second, through the centrifugal separation and coalescence of the hydrocyclone coalescer, combined with the synergistic addition of demulsifiers and flocculants, the oil-water separation effect is enhanced, and the microbubble adsorption of the air flotation machine further removes residual pollutants, ensuring the biodegradability of the effluent. In addition, the linkage design of the sludge dewatering system and the accident water tank not only realizes sludge reduction and odor control but also ensures the continuity and safety of wastewater treatment under accident conditions. The overall device operates efficiently and environmentally friendly. Description of the Drawings

[0029] Figure 1 It is a schematic structural diagram of the oil removal device for the pretreatment of oily sewage described in the utility model;

[0030] In the figure: 1. Inspection and filtration well; 2. Oil separation tank; 3. Sewage regulation tank; 4. Hydrocyclone coalescer; 5. High-efficiency air flotation machine; 6. Biochemical treatment system; 7. Floating oil collector; 8. Waste oil tank; 9. Sludge tank; 10. Sludge pump; 11. Screw press dewatering machine; 12. First self-priming pump; 13. Acid water stripping device; 14. Accident water tank; 15. Second self-priming pump; 16. Demulsifier dosing pipeline; 17. Flocculant dosing pipeline; 18. Upper coarse grille; 19. Middle fine grille; 20. Lower screen; 21. Electrically heated heat preservation pipe; 22. Cake conveyor belt; 23. Biological deodorization device. Detailed Embodiments

[0031] In order to make the purpose and technical solutions of the utility model clearer, the following further detailed description of the utility model is provided in conjunction with the drawings.

[0032] Embodiment 1

[0033] As Figure 1 shown, the oil removal device for the pretreatment of oily sewage described includes an inspection and filtration well 1, an oil separation tank 2, a sewage regulation tank 3, a hydrocyclone coalescer 4, and a high-efficiency air flotation machine 5 that are sequentially connected through process pipelines. The water outlet of the high-efficiency air flotation machine 5 is connected to the biochemical treatment system 6 through a pipeline;

[0034] A floating oil collector 7 is provided at the top of the oil separation tank 2 and is connected to the waste oil tank 8 through a floating oil discharge pipe. The light-phase outlet at the top of the hydrocyclone coalescer 4 is connected to the waste oil tank 8 through an oil-phase recovery pipe;

[0035] The heavy-phase outlet at the bottom of the hydrocyclone coalescer 4 is connected to the sludge discharge port of the high-efficiency closed air flotation machine 5 through a slag discharge pipeline and then to the sludge sump 9; the bottom outlet of the sludge sump 9 is connected to a spiral screw dewatering machine 11 through a sludge pump 10, and the water outlet of the spiral screw dewatering machine 11 is connected to the biochemical treatment system 6;

[0036] The sewage regulating tank 3 is connected to the feed inlet of the hydrocyclone coalescer 4 through a first self-priming pump 12 after converging with the purified water outlet pipeline of the acidic water stripping unit 13; the bottom of the oil separation tank 2 is connected to the sewage regulating tank 3 through a siphon;

[0037] An emergency water tank 14 is further included, and the outlet of the emergency water tank 14 is connected to the sewage regulating tank 3 through a second self-priming pump 15.

[0038] The top of the hydrocyclone coalescer 4 is connected with a demulsifier dosing pipeline 16 and a flocculant dosing pipeline 17.

[0039] The inspection and filtration well 1 is provided with a three-stage stepped grille, including: an upper coarse grille 18, a middle fine grille 19, and a lower screen 20.

[0040] An electric tracing heat preservation pipe 21 is provided between the floating oil collector 7 and the oily sewage tank 8.

[0041] A mud cake conveyor belt 22 is provided below the mud outlet of the spiral screw dewatering machine 11.

[0042] The top of the sludge sump 9 is provided with a biological deodorization device 23.

[0043] During operation, the specific process is as follows:

[0044] The oily sewage first enters the inspection and filtration well 1, and large particulate suspended matters, fibers, and fine impurities are intercepted step by step through the three-stage grille (upper coarse grille 18, middle fine grille 19, lower screen 20) to prevent subsequent equipment from being blocked. The filtered sewage is transported to the oil separation tank 2 through a process pipeline.

[0045] After the sewage enters the oil separation tank 2, the floating oil collector 7 continuously scrapes the surface floating oil, and the floating oil flows by gravity through the electric tracing heat preservation pipe 21 (maintaining 45±5°C) to the oily sewage tank 8 to prevent the oil layer from solidifying. The sewage without floating oil at the bottom of the oil separation tank 2 is transported to the sewage regulating tank 3 through a siphon.

[0046] The sewage regulating tank 3 equalizes and regulates the water volume and water quality to stabilize the inlet conditions of the subsequent treatment process. At the same time, the purified water (process wastewater) from the acidic water stripping unit 13 is mixed with the sewage in the regulating tank through the first self-priming pump 12, and the mixed sewage is lifted to the hydrocyclone coalescer 4 by the self-priming pump.

[0047] After the sewage enters the hydrocyclone coalescence separator 4, the three-phase separation of oil, water, and solids is achieved through the centrifugal inertial force generated by the hydrocyclone: the separated dirty oil is transported to the dirty oil tank 8 through the oil-phase recovery pipe from the top light-phase outlet, the oily sludge is discharged to the sludge tank 9 from the bottom heavy-phase outlet, and the separated sewage enters the high-efficiency airtight flotation machine 5.

[0048] During the separation process, the demulsifier and the flocculant are respectively mixed with the tangential feed pipe in a jet through the top demulsifier dosing pipeline 16 and the flocculant dosing pipeline 17 to enhance the demulsification and flocculation effects.

[0049] The effluent from the hydrocyclone coalescence separator 4 enters the high-efficiency airtight flotation machine 5, and the dissolved air water releases microbubbles (particle size 15±5μm) that adhere to the residual oil droplets and suspended solids to form scum. The scum is collected by the rotating sludge scraper and discharged into the sludge tank 9 through the slag discharge pipeline. The purified sewage enters the biochemical treatment system 6 through the water outlet.

[0050] The sludge tank 9 receives the scum and sludge from the hydrocyclone coalescence separator 4 and the high-efficiency airtight flotation machine 5, and is transported to the spiral press filter 11 through the sludge pump 10.

[0051] The spiral press filter 11 uses the principle of spiral extrusion to squeeze out the water in the sludge to form a sludge cake. The sludge cake is transported out through the sludge cake conveyor belt 22 for subsequent disposal.

[0052] A biological deodorization device 23 is provided at the top of the sludge tank 9 to reduce the odor pollution during the sludge treatment process by microbial degradation of malodorous gases such as hydrogen sulfide and ammonia.

[0053] In the event of an accident, the accident wastewater enters the plant accident water tank 14 through the cofferdam. The wastewater in the accident water tank 14 is lifted to the sewage regulation tank 3 by the second self-priming pump 15 and mixed with the normal sewage for treatment according to the conventional process to ensure the timely and effective disposal of the accident wastewater.

[0054] The described oily sewage pretreatment and oil removal device significantly reduces the oil content and suspended solid concentration of the sewage through multi-stage oil removal, homogenization adjustment, and deep separation, providing stable influent conditions for subsequent biochemical treatment.

Claims

1. An oily wastewater pretreatment and oil removal device, characterized in that: It comprises an inspection filter well (1), a grease trap (2), a sewage regulating tank (3), a cyclone coalescing separator (4) and a high-efficiency closed air flotation machine (5) which are sequentially connected through process pipelines, and the water outlet of the high-efficiency closed air flotation machine (5) is connected to a biochemical treatment system (6) through a pipeline; The top of the oil trap (2) is provided with a floating oil collector (7) and is connected to the waste oil tank (8) through a floating oil discharge pipe, and the light phase outlet at the top of the hydrocyclone coalescing separator (4) is connected to the waste oil tank (8) through an oil phase recovery pipe; The bottom heavy phase outlet of the hydrocyclone coalescence separator (4) and the mud discharge outlet of the high-efficiency closed air flotation machine (5) are connected to the mud slag pool (9) through a slag discharge pipeline; the bottom outlet of the mud slag pool (9) is connected to the screw press dewatering machine (11) through a sludge pump (10), and the water outlet of the screw press dewatering machine (11) is connected to the biochemical treatment system (6); The sewage regulating tank (3) is connected to the feed port of the hydrocyclone coalescing separator (4) through the first self-priming pump (12) and the purified water outlet pipe of the acidic water stripping device (13); the bottom of the oil separator (2) is connected to the sewage regulating tank (3) through a siphon; It also includes an accident water pool (14), the outlet of the accident water pool (14) being connected to the sewage regulating pool (3) via a second self-priming pump (15).

2. The oil-containing wastewater pretreatment and oil removal device according to claim 1 is characterized in that: The top of the hydrocyclone coalescence separator (4) is connected to a demulsifier dosing pipeline (16) and a flocculant dosing pipeline (17).

3. The oil-containing wastewater pretreatment and oil removal device according to claim 1 is characterized in that: The inspection filter well (1) is provided with a three-level stepped grid, comprising an upper coarse grid (18), a middle fine grid (19) and a lower screen (20).

4. The oil-containing wastewater pretreatment and oil removal device according to claim 1 is characterized in that: An electric heating and insulation pipe (21) is provided between the floating oil collector (7) and the dirty oil pool (8).

5. The oil-containing wastewater pretreatment and oil removal device according to claim 1 is characterized in that: A mud cake conveyor belt (22) is provided below the mud outlet of the screw stack dewatering machine (11).

6. The oily wastewater pretreatment and oil removal device according to claim 1, characterized in that: A biological deodorization device (23) is provided on the top of the sludge pool (9).

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