Three-phase separation system and separation method

Abstract

This invention discloses a three-phase separation system and method, belonging to the field of resource recycling technology. The system includes a grinding tank, a grinding device, a horizontal screw centrifuge, and an oil-water separator. The horizontal screw centrifuge includes a drum, a screw feeder, a first drive structure, a second drive structure, a feeding structure, a solid collection bin, a liquid collection bin, a guide cone, conveying blades, and a discharge structure. The screw feeder has a front connecting port at its front end, which is connected to the feeding structure. The rear end of the drum is conical, and the conveying blades can convey liquid forward when rotating. The screw feeder also has a rear connecting port at its rear end, which is connected to the discharge structure. The oil-water separator includes a separation bin, a heat-conducting baffle in the middle of the separation bin, and a heating structure on the heat-conducting baffle. The heat-conducting baffle divides the separation bin into a primary separation bin and a secondary separation bin, and its top is provided with an overflow port. The primary and secondary separation bins are respectively connected to the liquid collection bin and the discharge structure.

Description

Technical Field

[0001] This invention belongs to the field of resource recycling technology, and specifically relates to a three-phase separation system and separation method. Background Technology

[0002] Food waste refers to food processing scraps (kitchen waste) and food residues generated by the catering industry, such as schools, canteens, and restaurants. Its composition is very complex, mainly consisting of a mixture of various substances such as oil, water, fruit peels, vegetables, rice and flour, fish, meat, bones, as well as waste tableware, plastics, and paper towels. It is characterized by high solid content, low oil content, and complex impurity content.

[0003] In existing technologies, the process of processing food waste includes: impurity removal, grinding, solid-liquid separation, oil-water separation, and wastewater treatment. The solids obtained from solid-liquid separation can be used to produce organic matter or dried for use as fuel. The oil phase obtained from oil-water separation can be used to produce biodiesel, while the aqueous phase is used for wastewater treatment or to produce biogas followed by wastewater treatment. Existing technologies can employ grinding devices, horizontal screw centrifuges, and oil-water separators to perform the grinding, solid-liquid separation, and oil-water separation processes, respectively.

[0004] For example, patent application number CN201820502762.5 discloses a horizontal screw discharge sedimentation centrifuge for desalinating low-concentration saline wastewater, including a base and a cover hinged to the base; a drum is provided inside the cover, a screw conveyor is connected inside the drum, a drive wheel is connected to the drum, a drive motor is provided on one side of the drive wheel, and a transmission belt is connected between the drive motor and the drive wheel; a first tapered area is provided at the connection position between the drum and the drive wheel, and a second tapered area symmetrical to the first tapered area is provided at the end of the drum; the first tapered area is connected to a solid discharge port, and the second tapered area is connected to a liquid discharge port; the screw conveyor includes a rotating shaft and at least three helical blades detachably connected to the rotating shaft.

[0005] For example, patent application number CN201820503298.1 discloses an explosion-proof horizontal screw discharge sedimentation centrifuge, including a machine body, a casing fitted inside the machine body, and a base connected to the bottom of the casing; a rotating drum is provided inside the machine body, and the rotating drum is sealed inside the casing; a screw conveyor is connected inside the rotating drum, a centrifugal pump is sealed to one end of the rotating drum, a differential is connected to the other end of the rotating drum, and a drive assembly is connected to the differential; the casing is also filled with nitrogen, and a nitrogen alarm is connected to the casing; the machine body is provided with a discharge pipe communicating with the rotating drum, the discharge pipe including a first discharge pipe and a second discharge pipe connected in sequence, a universal joint connecting the first discharge pipe and the second discharge pipe, and a flexible hose sealingly connecting the first discharge pipe and the second discharge pipe respectively wrapped around the universal joint.

[0006] The oil-water mixture obtained from the horizontal screw centrifuge is sent to the oil-water separator for separation by settling. The oil-water separation takes a long time (usually 12-24 hours), which affects production efficiency. Summary of the Invention

[0007] To address the aforementioned problems, this invention provides a three-phase separation system and method, which can significantly reduce oil-water separation time and improve production efficiency. The technical solution is as follows:

[0008] On one hand, embodiments of the present invention provide a three-phase separation system, which includes a grinding tank, a grinding device, a horizontal screw centrifuge, and an oil-water separator. The grinding tank is connected to the water inlet of the grinding device, and the grinding device is connected to the feeding structure 5 of the horizontal screw centrifuge. The horizontal screw centrifuge includes a drum 1 arranged in a front-to-back direction, a screw unloader 2 coaxially penetrating the drum 1, a first drive structure 3 driving the drum 1 to rotate, a second drive structure 4 driving the screw unloader 2 to rotate, a feeding structure 5 at the front end of the screw unloader 2, a solid collection bin 6 at the front end of the drum 1, and a liquid collection bin 7 at the rear end of the drum 1. The drum 1 has a solid material outlet 8 and a liquid outlet 9 at its front and rear ends, respectively, located in the solid material collection bin 6 and the liquid collection bin 7. The front parts of both the drum 1 and the screw feeder 2 are mutually cooperating conical shapes. The front part of the screw feeder 2 is a hollow structure with a front connecting port 10, which communicates with the feeding structure 5 and is located in the middle of the drum 1. The horizontal screw centrifuge also includes a guide cone 11 (smaller at the front and larger at the rear) at the rear of the screw feeder 2, conveying blades 12 on the screw feeder 2 and located inside the guide cone 11, and a discharge structure 13 at the rear end of the screw feeder 2. The rear part of the drum 1... To match the guide cone 11 and form a cone shape that is smaller at the front and larger at the back, control valves are provided on both the liquid outlet 9 and the discharge structure 13. The conveying blades 12 can convey liquid forward when rotating. The rear of the screw unloader 2 is a hollow structure with a rear connecting port 14 located inside the guide cone 11. The rear connecting port 14 is located in front of the conveying blades 12 and communicates with the discharge structure 13. The oil-water separator includes a separation chamber, a heat-conducting baffle 21 in the middle of the separation chamber, and a heating structure 22 on the heat-conducting baffle 21. The heat-conducting baffle 21 divides the separation chamber into a primary separation chamber 23 and a secondary separation chamber 24, and its top is equipped with an overflow valve. Outlet 25 connects the primary separation chamber 23 and the secondary separation chamber 24. The middle parts of the primary separation chamber 23 and the secondary separation chamber 24 are respectively provided with a first feed inlet 26 and a second feed inlet 27. The bottom and lower part of the primary separation chamber 23 are respectively provided with a first drain outlet 28 and a drain outlet 29. The upper part and the bottom of the secondary separation chamber 24 are respectively provided with an oil drain outlet 30 and a second drain outlet 31. The first feed inlet 26 and the second feed inlet 27 are respectively connected to the liquid collection chamber 7 and the discharge structure 13. The first drain outlet 28 and the second drain outlet 31 are both connected to the grinding water tank. The oil drain outlet 30 is lower than the overflow outlet 25.

[0009] Furthermore, in this embodiment of the invention, the discharge structure 13 is connected to the second inlet 27 via a pipeline with a pump.

[0010] Specifically, in this embodiment of the invention, the screw unloader 2 has a hollow structure and is provided with a first partition 15 and a second partition 16 arranged side by side to divide the screw unloader 2 into three chambers. The first partition 15 is located adjacent to the rear of the front connecting port 10, and the second partition 16 is located adjacent to the front of the rear connecting port 14.

[0011] In this embodiment of the invention, the front and rear ends of the screw unloader 2 are rotatably and sealedly connected to the feeding structure 5 and the discharging structure 13, respectively, and the front and rear ends of the drum 1 are rotatably connected to the solid material collection bin 6 and the liquid collection bin 7, respectively.

[0012] Specifically, in this embodiment of the invention, the drum 1 consists of a discharge section 41, a front conical section 42, a straight section 43, and a rear conical section 44 from front to back. A drive wheel 45 is coaxially mounted on the rear end face of the rear conical section 44. The spiral blades of the spiral unloader 2 are located inside the front conical section 42 and the straight section 43. The guide cone 11 is located inside the rear conical section 44. The front connecting port 10 is located in the middle of the straight section 43. The inner diameter of the discharge section 41 is smaller than the inner diameter of the straight section 43. The front conical section 42 and the rear conical section 44 gradually increase in size from front to back. A solid material outlet 8 is provided on the circumferential surface of the discharge section 41 and is located in the solid material collection bin 6. A liquid outlet 9 is provided at the rear end of the circumferential surface of the rear conical section 44 and is located in the liquid collection bin 7. The drive wheel 45 extends rearward through the liquid collection bin 7 and is connected to the first drive structure 3.

[0013] In this embodiment of the invention, the separation chamber is a rectangular trough with an insulation layer on its wall. The first inlet 26 and the second inlet 27 are both formed by extending downward into the middle of the separation chamber through the feed pipe at the top of the separation chamber. The volume of the secondary separation chamber 24 is smaller than that of the primary separation chamber 23.

[0014] Preferably, in this embodiment of the invention, the lower part of the overflow port 25 is provided with a valve plate 32 that can move up and down.

[0015] Preferably, the feeding structure 5 in this embodiment of the invention is provided with a cleaning fluid inlet, and the drain outlet 29 is provided with a hot water branch pipe. The cleaning fluid inlet is connected to the hot water branch pipe through a pipeline with a pump and a valve.

[0016] On the other hand, embodiments of the present invention also provide a three-phase separation method, the method comprising:

[0017] S101 Grinding: The cleaned kitchen waste is fed into the grinding device for grinding, and at the same time, grinding water is supplied by the grinding water tank to adjust the solid content of the kitchen waste to 18-25%;

[0018] S102 Three-phase separation: The slurry obtained in step S101 is fed to the feed structure 5 of the horizontal screw centrifuge. Solids are obtained in the solid collection bin 6, liquids with low oil content are obtained in the liquid collection bin 7, and liquids with high oil content are obtained in the discharge structure 13. The control valves on the liquid outlet 9 and the discharge structure 13 and the rotation speed of the drum 1 are adjusted so that the oil content in the liquid with high oil content is greater than 40%.

[0019] S103 Oil-Water Separation: First, add clean water to the primary separation chamber 23, then add a liquid with low oil content; add a liquid with high oil content to the secondary separation chamber 24; control the flow rate of the drain outlet 29 to allow the oil phase in the primary separation chamber 23 to overflow into the secondary separation chamber 24; the oil phase is output from the oil outlet 30 of the secondary separation chamber 24; when there is no feed into the primary separation chamber 23 and the secondary separation chamber 24, the oil outlet 30 continues to be opened until most of the oil phase is output; open the first drain outlet 28 and the second drain outlet 31 to send the oil-water mixture in the primary separation chamber 23 and the remaining oil-water mixture in the secondary separation chamber 24 to the grinding water tank, respectively; during oil-water separation, the heating structure 22 heats the liquid to 50-80℃.

[0020] Furthermore, the three-phase separation method in this embodiment of the invention further includes:

[0021] S104 Cleaning: After the three-phase separation is completed, the aqueous phase in the primary separation chamber 23 is sent to the cleaning liquid inlet on the feed structure 5 through the drain outlet 29, and the horizontal screw centrifuge is run; when there is no feed into the primary separation chamber 23 and the secondary separation chamber 24, the first drain outlet 28 and the second drain outlet 31 are opened to send the remaining oil-water mixture in the primary separation chamber 23 and the remaining oil-water mixture in the secondary separation chamber 24 to the grinding water tank, respectively.

[0022] The present invention has the following advantages:

[0023] (1) The horizontal screw centrifuge is used to pre-separate the oil-water mixture (the separation effect is generally good). The oil content of the liquid with low oil content is less than 5%, and the oil content of the liquid with high oil content is greater than 40% (the amount is small). The two liquids are sent to the primary separation chamber and the secondary separation chamber for processing respectively. The oil-water separation speed is fast. Compared with the existing technology, the oil-water separation time is reduced by at least 50% (the horizontal screw centrifuge can achieve oil-water separation after half an hour of shutdown, and can basically achieve solid-liquid separation and oil-water separation process in the same shift). The horizontal screw centrifuge is usually used for processing during the day, and oil-water separation is carried out at the same time.

[0024] (2) The oil-water mixture from the oil-water separation is not discharged externally, but is used as grinding water for the grinding device, which reduces the difficulty of wastewater treatment and increases the yield of oil.

[0025] (3) The discharged wastewater is all water phase from the primary separation chamber (oil phase and sediment are both used as grinding water), so the wastewater treatment is easy;

[0026] (4) The horizontal spiral centrifuge is cleaned with the aqueous phase (hot water) in the primary separation chamber. The cleaning effect is good and saves water resources and energy.

[0027] (5) During oil-water separation, initially, only the aqueous phase is discharged from the primary separation chamber; after a period of time, the oil and water in the primary separation chamber separate, and the oil phase overflows to the secondary separation chamber; at this time, the oil phase in the secondary separation chamber has not yet reached the oil outlet, and oil-water separation is carried out; when the oil phase reaches the oil outlet, the oil-water separation effect is already good (the water content is usually less than 2%, and usually less than 1%), and the oil phase is continuously discharged from the oil outlet; the size of the secondary separation chamber is designed to be suitable, and no drainage is required per shift, and the oil-water mixture is finally output as grinding water. After the oil-water separator stops feeding, the liquid separation speed in the primary separation chamber is fast, and oil-water separation can be basically achieved in real time; the liquid separation speed in the secondary separation chamber is slow, and oil-water separation can also be achieved during the release of the oil phase. Attached Figure Description

[0028] Figure 1 This is a block diagram of the three-phase separation system.

[0029] Figure 2 This is a schematic diagram of a horizontal screw centrifuge;

[0030] Figure 3 This is a schematic diagram of an oil-water separator.

[0031] In the diagram: 1. Rotary drum, 2. Screw unloader, 3. First drive structure, 4. Second drive structure, 5. Feeding structure, 6. Solid material collection bin, 7. Liquid collection bin, 8. Solid material outlet, 9. Liquid outlet, 10. Front connecting port, 11. Guide cone, 12. Conveying blade, 13. Discharge structure, 14. Rear connecting port, 15. First partition, 16. Second partition.

[0032] 21 Thermal conductive baffle, 22 Heating structure, 23 Primary separation chamber, 24 Secondary separation chamber, 25 Overflow port, 26 First feed inlet, 27 Second feed inlet, 28 First drain port, 29 Drain port, 30 Oil drain port, 31 Second drain port, 32 Valve plate;

[0033] 41 Discharge section, 42 Front cone section, 43 Straight cylinder section, 44 Rear cone section, 45 Drive wheel. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings.

[0035] Example 1

[0036] See Figure 1-3 Example 1 provides a three-phase separation system, which includes a grinding water tank, a grinding device, a horizontal screw centrifuge, and an oil-water separator. The grinding water tank is used to store grinding water and is connected to the water inlet of the grinding device through a pipeline. The grinding device is used for grinding treatment, and its outlet is connected to the feed structure 5 of the horizontal screw centrifuge through a pipeline.

[0037] Among them, see Figure 2 The horizontal screw centrifuge includes a rotating drum 1 arranged in a front-to-back direction, a screw feeder 2 coaxially passing through the rotating drum 1, a first drive structure 3 driving the rotating drum 1 to rotate, a second drive structure 4 driving the screw feeder 2 to rotate, a feeding structure 5 at the front end of the screw feeder 2, a solid material collection bin 6 at the front end of the rotating drum 1, a liquid collection bin 7 at the rear end of the rotating drum 1, a guide cone 11 at the rear of the screw feeder 2 (smaller at the front and larger at the rear), conveying blades 12 on the screw feeder 2 and located inside the guide cone 11, and a discharge structure 13 at the rear end of the screw feeder 2. The rotating drum 1 has a solid material outlet 8 and a liquid outlet 9 at its front and rear ends, respectively, located in the solid material collection bin 6 and the liquid collection bin 7. Both the solid material collection bin 6 and the liquid collection bin 7 have discharge ports at their bottoms. The front parts of both the rotating drum 1 and the screw feeder 2 are mutually cooperating cones (smaller at the front and larger at the rear), and the screw feeder 2 is used to convey solid materials forward. The front part of the screw feeder 2 is a hollow structure with a front connecting port 10. The front connecting port 10 is connected to the feeding structure 5 and is located in the middle of the rotating drum 1, used to feed kitchen waste into the rotating drum 1. The guide cone 11 is a conical cylinder that is smaller at the front and larger at the back and is coaxial with the screw unloader 2, with a certain gap between its outer edge and the inner wall of the rotating drum 1. The rear part of the rotating drum 1 is a cone that fits with the guide cone 11 and is smaller at the front and larger at the back. Both the liquid outlet 9 and the discharge structure 13 are equipped with control valves, which can control the amount of liquid output from the liquid outlet 9 and the discharge structure 13 and the oil content of the liquid. When the conveying blade 12 rotates, it can convey liquid forward to send liquid with high oil content to the rear connecting port 14. The rear part of the screw unloader 2 is a hollow structure and has a rear connecting port 14 located inside the guide cone 11. The rear connecting port 14 is located in front of the conveying blade 12 and is connected to the discharge structure 13. The front and rear ends of the screw unloader 2 are rotary sealed to the feeding structure 5 and the discharge structure 13 respectively, and the front and rear ends of the drum 1 are rotary connected to the solid material collection bin 6 and the liquid collection bin 7 respectively.

[0038] Among them, see Figure 3The oil-water separator includes a separation chamber, a heat-conducting baffle 21 in the middle of the separation chamber, and a heating structure 22 on the heat-conducting baffle 21. The separation chamber is a rectangular tank with an insulation layer on its walls. The heat-conducting baffle 21 is specifically a metal plate. The heat-conducting baffle 21 divides the separation chamber into a primary separation chamber 23 and a secondary separation chamber 24, and its top has an overflow port 25 connecting the primary separation chamber 23 and the secondary separation chamber 24. That is, the top of the heat-conducting baffle 21 is lower than the top of the separation chamber. Since the amount of liquid with low oil content is much greater than that of liquid with high oil content, the volume of the secondary separation chamber 24 is smaller than that of the primary separation chamber 23. The middle parts of the primary separation chamber 23 and the secondary separation chamber 24 are respectively provided with a first inlet 26 and a second inlet 27. Both the first inlet 26 and the second inlet 27 are formed by extending downward into the middle of the separation chamber through the feed pipe at the top of the separation chamber. The bottom and lower part of the primary separation chamber 23 are respectively provided with a first drain outlet 28 (discharging an oil-water mixture (containing a large amount of solids)) and a drain outlet 29 (discharging clean water). The upper part and bottom of the secondary separation chamber 24 are respectively provided with an oil drain outlet 30 (discharging the oil phase) and a second drain outlet 31 (discharging the oil-water separator). The first feed inlet 26 and the second feed inlet 27 are respectively connected to the liquid collection chamber 7 and the discharge structure 13; furthermore, the discharge structure 13 is connected to the second feed inlet 27 through a pipeline with a pump to control the flow rate. The first drain outlet 28 and the second drain outlet 31 are both connected to the grinding water tank. The oil drain outlet 30 is lower than the overflow outlet 25. The aforementioned structures are connected by pipelines, and pumps, flow meters, or valves are installed on the pipelines as needed.

[0039] Specifically, see Figure 2 In this embodiment of the invention, the screw unloader 2 has a hollow structure (a tubular structure running through the front and back), and a first partition 15 and a second partition 16 are arranged side by side inside, dividing the screw unloader 2 into three chambers (the front chamber is for feeding, and the rear chamber is for outputting liquid with high oil content). The first partition 15 and the second partition 16 are perpendicular to the screw unloader 2. The first partition 15 is located adjacent to the rear of the front connecting port 10, and the second partition 16 is located adjacent to the front of the rear connecting port 14.

[0040] Specifically, see Figure 2In this embodiment of the invention, the drum 1 consists of a discharge section 41, a front conical section 42, a straight section 43, and a rear conical section 44, arranged from front to back. A drive wheel 45 is coaxially mounted on the rear end face of the rear conical section 44. The front conical section 42 is located in the cone shape at the front of the drum 1. The spiral blades of the spiral unloader 2 are located inside the front conical section 42 and the straight section 43. The guide cone 11 is located inside the rear conical section 44. The front connecting port 10 is located in the middle of the straight section 43. The inner diameter of the discharge section 41 is smaller than the inner diameter of the straight section 43. Both the front conical section 42 and the rear conical section 44 gradually increase in size from front to back. A solid material outlet 8 is provided on the circumference of the discharge section 41 and is located in the solid material collection bin 6. A liquid outlet 9 is provided at the rear end of the circumference of the rear conical section 44 and is located in the liquid collection bin 7. The drive wheel 45 extends rearward through the liquid collection bin 7 and is connected to the first drive structure 3.

[0041] Preferably, see Figure 3 In this embodiment of the invention, the lower part of the overflow port 25 is provided with a valve plate 32 that can move up and down to control the overflow speed of the oil phase. Specifically, the valve plate 32 is slidably disposed in the separation chamber and its top is provided with an adjusting rod in the vertical direction. The adjusting rod extends upward out of the separation chamber and can be adjusted up and down.

[0042] Preferably, see Figure 1 In this embodiment of the invention, the feeding structure 5 (with a three-way interface, one inlet for feeding and the other inlet for cleaning liquid) is provided with a cleaning liquid inlet, and the drain outlet 29 (with a three-way interface, one outlet for draining and the other outlet for discharging cleaning liquid) is provided with a hot water branch pipe. The cleaning liquid inlet is connected to the hot water branch pipe through a pipeline with a pump and a valve.

[0043] Example 2

[0044] Example 2 provides a three-phase separation method using the three-phase separation system provided in Example 1. The method includes:

[0045] S101 Pulping: The kitchen waste that has been cleaned (usually including large object separation and magnetic separation) is sent into the pulping device for pulping, and at the same time, the pulping water tank provides pulping water to adjust the solid content of the kitchen waste to 18-25%.

[0046] S102 Three-phase separation: The slurry obtained in step S101 is fed to the feed structure 5 of the horizontal screw centrifuge. Solids are obtained in the solid collection bin 6, liquids with low oil content are obtained in the liquid collection bin 7, and liquids with high oil content are obtained in the discharge structure 13. The control valves on the liquid outlet 9 and the discharge structure 13 and the rotation speed of the drum 1 are adjusted so that the oil content in the liquid with high oil content is greater than 40% (volume concentration, the same below), and the oil content in the liquid with low oil content is usually less than 5%.

[0047] S103 Oil-Water Separation: First, add clean water (appropriate amount) to the primary separation chamber 23, then add a liquid with low oil content; add a liquid with high oil content to the secondary separation chamber 24. Control the flow rate of the drain outlet 29 to allow the oil phase in the primary separation chamber 23 to overflow into the secondary separation chamber 24. The oil phase is discharged from the oil outlet 30 of the secondary separation chamber 24. The volume of the secondary separation chamber 24 is set to a certain size so that the water phase does not need to be discharged during one shift (e.g., 8 hours). Of course, if the water phase is about to reach the oil outlet 30, it can also be discharged to the grinding tank. When there is no feed into the primary separation chamber 23 and the secondary separation chamber 24 (three-phase separation is completed), the oil outlet 30 continues to be opened until most of the oil phase is discharged (the top of the oil phase descends to the oil outlet 30). Open the first drain outlet 28 and the second drain outlet 31 to send the oil-water mixture (or the remaining oil-water mixture) in the primary separation chamber 23 and the remaining oil-water mixture in the secondary separation chamber 24 to the grinding tank, respectively. During oil-water separation, the heating structure 22 heats the liquid to 50-80℃. In this patent, the oil-water mixture from the primary separation chamber 23 is output to the grinding tank because it contains a large amount of solid matter and a small amount of grease; the oil-water mixture from the secondary separation chamber 24 is output to the grinding tank because the oil-water mixture can no longer be discharged after it drops to the oil drain port 30, and it contains a large amount of grease.

[0048] Furthermore, the three-phase separation method in this embodiment of the invention further includes:

[0049] S104 Cleaning: After the three-phase separation is completed, the aqueous phase (with a higher temperature and better cleaning effect) in the primary separation chamber 23 is sent to the cleaning liquid inlet on the feed structure 5 through the drain outlet 29, and the horizontal screw centrifuge is run. When there is no feed into the primary separation chamber 23 and the secondary separation chamber 24, the first drain outlet 28 and the second drain outlet 31 are opened to send the remaining oil-water mixture in the primary separation chamber 23 and the remaining oil-water mixture in the secondary separation chamber 24 to the grinding water tank, respectively. For the horizontal screw centrifuge, after cleaning using the above method, it can also be cleaned with clean water.

[0050] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A three-phase separation system comprising a pulp water tank, a pulping device, a horizontal screw centrifuge and an oil-water separator, the pulp water tank being connected with a water supplementing port of the pulping device, the pulping device being connected with a feed structure (5) of the horizontal screw centrifuge; the horizontal screw centrifuge comprising a rotating drum (1) arranged along a front-rear direction, a screw discharger (2) coaxially penetrating the rotating drum (1), a first driving structure (3) driving the rotating drum (1) to rotate, a second driving structure (4) driving the screw discharger (2) to rotate, a feed structure (5) at a front end of the screw discharger (2), a solid collection bin (6) at a front end of the rotating drum (1) and a liquid collection bin (7) at a rear end of the rotating drum (1), the front-rear ends of the rotating drum (1) being respectively provided with a solid outlet (8) and a liquid outlet (9) and being respectively located in the solid collection bin (6) and the liquid collection bin (7), the front parts of the rotating drum (1) and the screw discharger (2) being tapered and matched with each other, the front part of the screw discharger (2) being a hollow structure and being provided with a front communication port (10) thereon, the front communication port (10) being communicated with the feed structure (5) and being located in a middle part of the rotating drum (1); characterized in that, the horizontal screw centrifuge further comprises a guide tapered cylinder (11) at a rear part of the screw discharger (2) and being tapered from small in front to large in rear, a conveying blade (12) on the screw discharger (2) and being located in the guide tapered cylinder (11), and a discharge structure (13) at a rear end of the screw discharger (2), the rear part of the rotating drum (1) being tapered and matched with the guide tapered cylinder (11) and being tapered from small in front to large in rear, the liquid outlet (9) and the discharge structure (13) being respectively provided with a control valve, the conveying blade (12) being capable of conveying liquid forward when rotating, the rear part of the screw discharger (2) being a hollow structure and being provided with a rear communication port (14) thereon and located in the guide tapered cylinder (11), the rear communication port (14) being located in front of the conveying blade (12) and being communicated with the discharge structure (13); the oil-water separator comprising a separation bin, a heat-conducting partition plate (21) in a middle part of the separation bin and a heating structure (22) on the heat-conducting partition plate (21), the heat-conducting partition plate (21) dividing the separation bin into a first separation bin (23) and a second separation bin (24) and being provided with an overflow port (25) at a top part thereof to communicate the first separation bin (23) and the second separation bin (24), the middle parts of the first separation bin (23) and the second separation bin (24) being respectively provided with a first feed port (26) and a second feed port (27), the bottom part and the lower part of the first separation bin (23) being respectively provided with a first blowdown port (28) and a drainage port (29), the upper part and the bottom part of the second separation bin (24) being respectively provided with an oil discharge port (30) and a second blowdown port (31), the first feed port (26) and the second feed port (27) being connected with the liquid collection bin (7) and the discharge structure (13) respectively, the first blowdown port (28) and the second blowdown port (31) being connected with the pulp water tank, and the oil discharge port (30) being lower than the overflow port (25). The spiral discharger (2) is a hollow structure, and a first partition plate (15) and a second partition plate (16) are arranged side by side in front and back in the spiral discharger (2) to divide the spiral discharger (2) into three cavities, the first partition plate (15) is located adjacent to the rear of the front communication port (10), and the second partition plate (16) is located adjacent to the front of the rear communication port (14).

2. The three-phase separation system of claim 1, wherein, The discharge structure (13) is connected with the second feeding port (27) through a pipeline with a pump.

3. The three-phase separation system of claim 1, wherein, The front end and the rear end of the spiral discharger (2) are respectively rotatably connected with the feeding structure (5) and the discharge structure (13), and the front end and the rear end of the rotary drum (1) are respectively rotatably connected with the solid collection bin (6) and the liquid collection bin (7).

4. The three-phase separation system of claim 1, wherein, The rotary drum (1) sequentially comprises, from front to back, a discharge section (41), a front conical cylinder section (42), a straight cylinder section (43) and a rear conical cylinder section (44), a driving wheel (45) is coaxially arranged on the rear end surface of the rear conical cylinder section (44), the spiral blade of the spiral discharger (2) is located in the front conical cylinder section (42) and the straight cylinder section (43), the guide conical cylinder (11) is located in the rear conical cylinder section (44), the front communication port (10) is located in the middle of the straight cylinder section (43), the inner diameter of the discharge section (41) is smaller than that of the straight cylinder section (43), the front conical cylinder section (42) and the rear conical cylinder section (44) are gradually increased from front to back, the solid outlet (8) is arranged on the circumferential surface of the discharge section (41) and located in the solid collection bin (6), the liquid outlet (9) is arranged on the rear end of the circumferential surface of the rear conical cylinder section (44) and located in the liquid collection bin (7), and the driving wheel (45) penetrates out of the liquid collection bin (7) and is drivingly connected with the first driving structure (3).

5. The three-phase separation system of claim 1, wherein, The separation bin is a rectangular groove, and a heat preservation layer is arranged on the groove wall, the first feeding port (26) and the second feeding port (27) are both formed by feeding pipes on the top of the separation bin and downwardly extending into the middle part of the separation bin, and the volume of the secondary separation bin (24) is smaller than that of the primary separation bin (23).

6. The three-phase separation system of claim 1, wherein, The lower part of the overflow port (25) is provided with a valve plate (32) capable of moving up and down.

7. The three-phase separation system of claim 1, wherein, The feeding structure (5) is provided with a cleaning liquid inlet, the drain port (29) is provided with a hot water branch pipe, and the cleaning liquid inlet is connected with the hot water branch pipe through a pipeline with a pump and a valve.

8. A method for three-phase separation using a three-phase separation system according to any one of claims 1 to 7, characterised in that, The method comprises: S101, grinding: the kitchen waste after impurity removal is sent to a grinding device for grinding, and at the same time, grinding water is provided from a grinding water tank to adjust the solid content of the kitchen waste to 18-25%; S102, three-phase separation: the slurry obtained in step S101 is sent to the feeding structure (5) of a horizontal screw centrifuge, solid is obtained in the solid collection bin (6), low-oil-content liquid is obtained in the liquid collection bin (7), and high-oil-content liquid is obtained in the discharge structure (13), the control valves on the liquid outlet (9) and the discharge structure (13) and the rotating speed of the rotary drum (1) are adjusted so that the grease content in the high-oil-content liquid is greater than 40%; S103 oil-water separation: first add clean water in the first separation bin (23), then add liquid with low oil content; add liquid with high oil content in the second separation bin (24); control the flow rate of the water outlet (29) to make the oil phase in the first separation bin (23) overflow to the second separation bin (24); the oil outlet (30) of the second separation bin (24) outputs the oil phase; when the first separation bin (23) and the second separation bin (24) have no feed, the oil outlet (30) is continuously opened until most of the oil phase is output; open the first blowdown outlet (28) and the second blowdown outlet (31) to send the oil-water mixture in the first separation bin (23) and the remaining oil-water mixture in the second separation bin (24) to the grinding water tank, respectively; when the oil-water separation is performed, the heating structure (22) heats the temperature of the liquid to 50-80℃.

9. The three-phase separation method of claim 8, wherein, The method comprises: S104 cleaning: after the three-phase separation is completed, the water phase in the first separation bin (23) is sent to the cleaning liquid inlet on the feed structure (5) through the water outlet (29), and the horizontal screw centrifuge is operated; when the first separation bin (23) and the second separation bin (24) have no feed, the first blowdown outlet (28) and the second blowdown outlet (31) are opened to send the remaining oil-water mixture in the first separation bin (23) and the remaining oil-water mixture in the second separation bin (24) to the grinding water tank, respectively.

Images