Oil-water separation system

Abstract

The utility model discloses an oil-water separation system which comprises a centrifugal separation device, a gravity separation device and a filter membrane separation device. The centrifugal separation device comprises an upper cone and a lower cone; the upper cone is provided with a positioning oil outlet; the upper part of the lower cone is provided with a tangent inlet, the lower part of the lower cone is provided with a bowl buckling outlet, and the bottom of the lower cone is provided with a sludge opening. A gas outlet is formed in the top of the gravity separation device, a gas boiling device is arranged at the bottom of the gravity separation device, a water outlet is formed below the gravity separation device, a floating ball and a hose are arranged in the device, an oil outlet is formed in the floating ball, and a bottom opening is connected with an oil drain pipe through the hose. The filter membrane separation device is divided into a front cavity and a rear cavity by a filter membrane, the filter membrane is fixed by a permeable plate, and a floating ball and a hose are arranged in the front cavity. The oil-water separator combines oil-water separation principles of centrifugation, gravity, filter membranes and the like, and can realize oil-water separation with large flow, high efficiency and low energy consumption.

Description

Technical Field

[0001] The utility model is applied to the field of chemical industry and relates to oil-water separation, in particular to an oil-water separation system which separates oil and water by utilizing the respective characteristics of oil and water. Background Art

[0002] In the chemical industry, high-temperature cracking reactions and water spray cooling are common. Oil-water mixtures are the products of reaction cooling. In order to reuse water or oil and prepare for subsequent processing, oil-water separation is an inevitable process step. Oil-water separation uses the fact that oil and water are insoluble, have different specific gravities, and have different atomic sizes. There are centrifugal separation, gravity separation, filtration separation, etc. Common separation devices include three-phase separators, hydrocyclone separators, flotation separation devices, membrane filtration separation devices, etc.

[0003] In terms of oil-water separation filter materials, there are many patent applications, such as CN115430177A provides an oil-water separation coalesced fiber material, CN109289251A discloses an oil-water separation composite filter material, CN108939692B discloses a super-hydrophobic coating for oil-water separation, CN108854583B provides a method for preparing a hydrophilic oil-water separation membrane with a spider web structure, CN102698471B provides an oil-water separation mesh membrane and its preparation method, CN209333256U provides an oil-water separation composite filter material, CN209405745U provides a coalesced fiber material for oil-water separation, and so on.

[0004] In terms of oil-water separation devices, different devices use different separation methods, or a single method, or a combination of two separation methods, or a combination of multiple methods. For example, CN208603870U provides an oil-water separation device, which is provided with a separation part containing a hydrophilic membrane for oil-water separation. Although the structure is simple, the burden of the hydrophilic membrane is heavy for oil-water mixed liquid with a large oil content; CN213295260U provides an oil-water separator, which uses gravity separation to form a primary oil-water gravity separation chamber and a secondary oil-water gravity separation chamber through a liquid distribution device and a weir plate assembly. This oil-water separator needs to provide sufficient floating time for the oil film, and the efficiency of oil-water separation is low. There is also CN203173863U which provides an oil-water separator with a horizontal tank structure. A nitrogen stirring tube is arranged in the separation zone, and gas and gravity are used to separate oil and water; as well as CN217025420U oil-water separation device, CN115970340A a petrochemical oil-water separation system and separation method, CN208603870U a multi-stage oil-water separation device for chemical wastewater, etc., which achieve oil-water separation by two methods: centrifugation and filter element (or filtration). There are also multiple separation methods used in combination, such as CN208414038U, a petrochemical oil-water separation device, which combines gravity separation, filtration and centrifugal separation to separate floating oil, dispersed oil, solid-attached oil and emulsified oil in water in turn; CN115557631A provides an oil-water separation device and method integrating cyclone-flotation-medium coalescence, which involves cyclone pre-separation and solid removal, micro-nano bubble coupling inclined plate coalescence enhanced oil removal and nano bubble coupling fiber coalescence deep oil removal, and adopts a method of coupling separation of micro-nano bubbles and multiple coalescence media in a cyclone field to improve the efficiency of solid removal and oil removal from sewage; CN101810941B composite oil-water separation system, which comprehensively uses multiple principles such as rationality, gravity, and expansion compound, overcomes the disadvantage of low processing efficiency of separation methods using a single principle under different working conditions, and improves separation efficiency.

[0005] In short, the combination of multiple oil-water separation methods has high separation efficiency and thorough oil-water separation. To this end, based on the existing technology, an oil-water separation system suitable for large-scale industrial production is proposed. Utility Model Content

[0006] The technical problem solved by the utility model is to provide an oil-water separation system, which adopts three oil-water separation methods of centrifugation, gravity and filter membrane in combination, can effectively remove free, emulsified and dissolved oil products, is suitable for large-flow oil-water mixtures in production, and can achieve oil-water separation with high efficiency and low energy consumption.

[0007] The technical solution adopted by the utility model is: the oil-water separation system includes a centrifugal separation device, a gravity separation device and a filter membrane separation device from front to back, and the three devices are connected by pipelines. The centrifugal separation device includes an upper cone and a lower cone; the upper cone is provided with a positioning oil outlet; the diameter of the lower cone gradually decreases downward, and a tangent inlet is provided at the upper part, a buckle bowl outlet is provided at the lower part, and the bottom is a sludge outlet. The buckle bowl outlet is located between the inner wall and the center of the lower cone to prevent the oil film and sludge from being discharged. A bottom ring is provided below the buckle bowl outlet, and an annular gap is retained between the bottom ring and the inner wall of the lower cone. When the sludge outlet valve is opened, water flows down from the annular gap to flush the sludge in the sludge outlet.

[0008] Preferably, in order to increase the rotation speed and improve the centrifugal separation effect, a stirring device is arranged at the top of the upper cone, and the stirrer of the stirring device extends into the tangent inlet position. The stirrer can increase the rotation speed and improve the centrifugal oil-water separation effect.

[0009] Preferably, the bottom ring is convex spherical, which can increase the flow rate of the water flow in the annular gap and improve the sludge flushing effect. An observation port is set at the upper part of the sludge port, and the observation port is sealed by glass or transparent mica, which can facilitate the observation of the amount of sludge.

[0010] Preferably, an inclined boiling plate or boiling pipe is provided at the bottom of the gravity separation device, and the boiling plate or boiling pipe is connected to compressed air to introduce boiling small bubbles into the device, and a drain outlet is provided below it. An air outlet is provided at the top of the gravity separation device to discharge the air in the device. A float II and a hose II are provided in the gravity separation device, and an oil drain outlet is designed on the float II. The bottom opening of the float II is connected to the middle oil drain pipe through the hose II. The float II can float above the water surface and sink below the oil surface.

[0011] Preferably, when the oil content in the oil-water mixture is low, the centrifugal separation device and the gravity separation device can be combined. The float II and the hose II are arranged in the centrifugal separation device, and no positioning oil outlet is arranged; the hose II is connected to the bottom opening of the float II and the middle oil discharge pipe. A boiling air ring pipe is arranged above the buckle bowl outlet to introduce small bubbles of boiling compressed air.

[0012] Preferably, the membrane separation device is divided into a front chamber and a rear chamber by a membrane, and the membrane is supported and fixed by a water-permeable plate. A float III and a hose III are arranged in the front chamber, and an oil discharge port is designed on the float III. The bottom opening of the float III is connected to the middle oil discharge pipe through the hose III. The membrane separation device is three in parallel, which can be used simultaneously or two can be used as a backup.

[0013] The beneficial effects of the utility model are as follows: the utility model makes full use of the three oil-water separation principles of centrifugal, gravity and filter membrane to completely separate the free, emulsified and dissolved oil products in the oil-water mixture. Centrifugal and gravity separation reduces the working pressure of the filter membrane and can achieve oil-water separation with large flow, high efficiency and low energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the front view of the structure of Example 1;

[0015] Figure 2 yes Figure 1 A schematic cross-sectional view of AA;

[0016] Figure 3 It is a schematic diagram of the float structure;

[0017] Figure 4 is a front view schematic diagram of the centrifugal separation device of Example 2;

[0018] Figure 5 is a schematic top view of the structural arrangement of Example 3;

[0019] Figure 6 is a schematic diagram of the front view of the structure of Example 4;

[0020] In the figure: 1-centrifugal separation device, 2-gravity separation device, 3-membrane separation device, 4-oil pipe;

[0021] 11- tangent inlet, 12- buckle bowl outlet, 13- sludge outlet, 14- positioning oil outlet, 15- inspection port Ⅰ, 16- oil level Ⅰ, 17- bottom ring, 18- observation port, 19- annular gap, 110- agitator;

[0022] 21-boiling gas plate, 22-hose II, 23-floating ball II, 24-gas outlet, 25-inspection port II, 26-oil level II, 27-boiling gas pipe, 28-boiling gas ring pipe;

[0023] 31-front cavity, 32-filter membrane, 33-water permeable plate, 34-rear cavity, 35-oil level III, 36-float III, 37-hose III. DETAILED DESCRIPTION

[0024] The following front and back refer to the relative positions determined before and after the degreasing process, the following up and down refer to the relative positions of the up and down in the use state, and the following inside and outside refer to the inside and outside of the device. The above Ⅰ, Ⅱ, and Ⅲ do not represent the order, but are only for the distinction of components. The solid arrows in the attached drawings are the flow direction of water, and the dotted arrows are the flow direction of oil.

[0025] Example 1.

[0026] The structure of the oil-water separation system of this embodiment is shown in the attached figure. Figure 1and attached Figure 2 As shown, it includes, from front to back, a centrifugal separation device 1, a gravity separation device 2, and a membrane separation device 3.

[0027] The centrifugal separation device 1 is a device in this system that uses centrifugal force to separate oil and water. Figure 1 As shown, it includes an upper cone and a lower cone. A positioning oil outlet 14 is provided on the upper cone for collecting and discharging oil. The positioning oil outlet 14 corresponds to the height of the oil level Ⅰ16, which is determined by the pressure of the oil-water mixture when it is fed in. The lower cone is used for centrifugal oil-water separation. A tangent inlet 11 for the oil-water mixture is provided at the upper part of the lower cone, and a buckle bowl outlet 12 is provided at the lower part. The buckle bowl outlet 12 refers to a pipe outlet that bends downward to prevent sinking sludge and floating free oil from entering. The buckle bowl outlet 12 discharges the oil-water mixture with less oil that has been initially separated from oil and water into the gravity separation device 2. A bottom ring 17 is provided below the buckle bowl outlet 12. The bottom ring 17 is fixed to the lower part of the lower cone, and an annular gap 19 is retained between the bottom ring 17 and the inner wall of the lower cone, as shown in the attached figure. Figure 2 As shown. The bottom of the lower cone is a sludge port 13, and an observation port 18 is arranged on the upper part of the sludge port 13. The observation port 18 is sealed with glass or transparent mica, and the amount of sludge at the bottom can be observed through the glass or mica. An inspection port I 15 is arranged on the top of the lower cone to facilitate the inspection of the equipment operation status.

[0028] The gravity separation device 2 is a device for oil-water separation in this system by utilizing the difference in specific gravity between oil and water. A boiling plate 21 is arranged at the bottom of this device, and the boiling plate 21 is connected to the compressed air, and is used to send small bubbles of compressed air into this device. A drainage port is arranged below the boiling plate 21, and is used to discharge the micro-oil-water mixture after the secondary oil-water separation into the membrane separation device 3. An air outlet 24 is arranged at the top of the gravity separation device 2, and the air sent into this device is discharged. The lower part of the air outlet 24 is a cone section, which is used for collecting oil. An inspection port Ⅱ25 is arranged on the cone section, which is used for checking the production process. A floating ball Ⅱ23 is arranged in the gravity separation device 2, and the floating ball Ⅱ23 floats on the water surface and sinks below the oil surface. Its bottom opening is connected to the oil discharge pipe installed in the middle of this device through a hose Ⅱ22. An oil discharge port is designed on the floating ball Ⅱ23, and the oil discharge port is located above the water surface and within the range of the thickness of the oil liquid surface Ⅱ26. The oil at the oil level II26 can flow into the float II23 through the oil drain port, and then flow into the oil pipe 4 through the hose II22 and the oil drain pipe. The biggest benefit of using the float to drain oil is that there is no need to consider the liquid pressure, the oil drain port can be adjusted with the water level, and is always located above the water surface, so there will be no drainage, which provides convenience for system control.

[0029] The filter membrane separation device 3 is a device for oil-water separation in this system by utilizing the water-permeable but oil-impermeable characteristics of the filter membrane. The size of water molecules is smaller than that of oil molecules. The filter pores of the filter membrane are located between the two molecules, which can pass water molecules and block oil molecules to achieve oil-water separation. The device is divided into a front chamber 31 and a rear chamber 34 by a filter membrane 32, and the filter membrane 32 is supported and fixed by a water-permeable plate 33. The front chamber 31 is connected to the gravity separation device through a pipeline, and the rear chamber 34 is provided with a drain port, which is connected to a water pump. The water pump forms a water pressure difference between the front chamber 31 and the rear chamber 34, which helps to improve the water permeability efficiency of the filter membrane 32. In the front chamber 31, a float III 36 is provided. The float III 36 floats above the water surface and sinks below the oil surface. Its bottom opening is connected to the oil drain pipe through a hose III 37. On the float III 36, an oil drain port is designed, which is located above the water surface and within the range of the thickness of the oil liquid surface III 35. The collected oil can flow into the float III 36 through the oil drain port, and then flow into the oil pipe 4 through the hose III 37 and the oil drain pipe.

[0030] When this embodiment is used, the oil-water mixture enters the centrifugal separation device 1 from the tangential inlet 11 under pressure, rotates and flows in the lower cone, generates centrifugal force, and the diameter of the lower cone gradually decreases downward, the rotational flow rate gradually increases, and the centrifugal force becomes more obvious. Under the action of centrifugal force, the sludge with a specific gravity greater than water is thrown to the inner wall of the cone, and falls along the inner wall through the annular seam 19 to the sludge outlet 13 at the bottom of the centrifugal separation device. The free oil with a specific gravity less than water gradually concentrates to the center of the lower cone under the action of centrifugal force, and floats into the upper cone, is discharged from the positioning oil outlet 14, and flows into the oil pipe 4. The centrifugal separation device 1 is the first step of oil-water separation in this system, which is used to separate the larger free oil from water. The free oil generally accounts for 80%-90% of the oil content. The oil-water mixture with less oil after preliminary separation flows into the gravity separation device 2 from the buckle bowl outlet 12. The buckle bowl outlet 12 is located between the inner wall and the center of the lower cone, and this position can prevent sludge and free oil from being brought into the gravity separation device 2. If a lot of sludge is observed from the observation port 18, the valve below the sludge port 13 can be opened, and the oil-water mixture with little oil in the centrifugal separation device 1 will flow down from the annular gap 19 under pressure, flushing away the sludge accumulated on the inner wall of the sludge port 13, and achieving efficient water flushing.

[0031] After the oil-less oil-water mixture flows into the gravity separation device 2, the space size increases, the flow rate slows down, and the air bubbles discharged from the bottom boiling plate 21 float up to form boiling. The surface tension of oil is greater than the surface tension of water, and the specific gravity of oil is less than the specific gravity of water. The floating bubbles absorb small-sized emulsified oil droplets and float up and gather. The emulsified oil is generally evenly dispersed in the water, accounting for 10%-15% of the total oil content, and flotation separation is usually used. The emulsified oil gathers above the water surface to form an oil liquid surface II26. The gathered oil flows into the oil pipe 4 through the oil discharge port, hose and oil discharge pipe on the float II23. The drain port is set below the boiling plate 21, and the micro-oil oil-water mixture after the small-sized oil droplets are removed is sent to the filter membrane separation device 3.

[0032] The micro-oil-water mixture entering the membrane separation device 3 is filtered by the membrane 32, and the water after passing through the membrane 32 flows into the rear chamber 34 and is discharged to the outside for reuse. The membrane 32 filters the micro-sized dissolved oil products, and a very small part of the oil products are dissolved in the water. The dissolved oil products gradually gather and float above the water surface to form an oil level III35. The floating oil flows into the oil pipe 4 through the oil discharge port on the float III36, the hose III37 and the oil discharge pipe. The oil pipe 4 collects the oil discharged from the centrifugal separation device 1, the gravity separation device 2 and the membrane separation device 3, enters the oil storage tank, and enters the subsequent process for processing or reuse.

[0033] This embodiment only describes the functions and steps of oil-water separation. Although the liquid pressure is taken into consideration in the structural design, the matching of the liquid flow rate is not considered.

[0034] Example 2.

[0035] The difference between this embodiment and the above-mentioned embodiment lies in the difference of the centrifugal separation device. The structure of the centrifugal separation device in this embodiment is as shown in the attached figure. Figure 4 As shown. The inspection port Ⅰ15 at the top of the upper cone in Example 1 is set on the side, and a stirring device is set on the top. The stirrer 110 of the stirring device extends into the position of the tangent inlet 11 to accelerate the rotation speed of the oil-water mixture and increase the centrifugal force. In this way, the height of the oil level Ⅰ16 can be adjusted by the pressure of the liquid inlet, and the rotation speed and centrifugal force can be adjusted by the stirrer 110 to promote the centrifugal separation of oil and water.

[0036] The bottom ring 17 disposed at the bottom is changed from a flat surface to a convex spherical surface, which is conducive to accelerating the flow rate of water in the annular gap 19 and quickly washing the sludge. The centrifugally thrown sludge falls from the inner wall through the annular gap 19 to the sludge outlet 13. Sludge will inevitably be deposited on the outer edge of the bottom ring 17. The convex spherical surface can effectively clean the sludge on the outer edge under the action of water flow.

[0037] Example 3.

[0038] The layout diagram of this embodiment is shown in the attached Figure 5As shown, compared with the above two embodiments, the focus is on the structure of the gravity separation device 2 and the number of the membrane separation devices 3.

[0039] The gravity separation device 2 of this embodiment is in the shape of a long strip in the direction of water flow to increase the time for the oil droplets to float. The boiling plate 21 in Example 1 is changed to a boiling pipe 27, and the small bubbles are stirred by boiling to make the oil droplets float. Considering the water permeability of the filter membrane 32 in the filter membrane separation device 3 and the replacement of the filter membrane, the filter membrane separation device 3 is set to three parallel units, which can work at the same time or use two as a backup. The three drain outlets of the gravity separation device 2 are all set below the boiling pipe 27.

[0040] Example 4.

[0041] The above three embodiments are all aimed at the situation where the oil content in the oil-water mixture is high, and are divided into three stages of separation: centrifugal separation of free oil, the oil-water mixture is separated into a low-oil oil-water mixture; gravity separation of emulsified oil droplets, the low-oil oil-water mixture is separated into a micro-oil oil-water mixture; filtration separation of dissolved oil, the low-oil oil-water mixture is completely separated from oil and water. The first two stages of oil-water separation greatly reduce the pressure of oil-water separation by the filter membrane. However, for the situation where the oil content in the oil-water mixture is not much, this embodiment can be used.

[0042] This embodiment combines centrifugal separation and gravity separation into one, that is, the centrifugal separation device 1 and the gravity separation device 2 are combined into a centrifugal gravity separation device. The structure of the device is shown in the attached figure. Figure 6 As shown. Since the oil content in the oil-water mixture is relatively low, the thickness of the oil surface Ⅰ16 is relatively small, and the liquid pressure of the tangent inlet 11 also fluctuates, it is not appropriate to use a positioning oil outlet 14 to prevent the positioning oil outlet 14 from draining water due to hydraulic floating. Hose Ⅱ22 and float Ⅱ23 are arranged in a centrifugal separation device, an oil outlet is arranged in the middle of the device, and hose Ⅱ22 connects the bottom of float Ⅱ23 and the oil outlet of the oil drain pipe. A boiling gas ring tube 28 is arranged above the buckle bowl outlet 12. The boiling gas ring tube 28 is connected to compressed air externally and small bubbles are discharged internally, so that small oil droplets adhere to the bubbles and centrifuge to the center, and are infiltrated and adsorbed into a large oil film and float. The membrane separation device 3 of this embodiment is the same as that of embodiment 1.

[0043] The above structures not described in detail all belong to the prior art.

[0044] The utility model makes full use of the oil-water separation principle and adopts three oil-water separation methods: centrifugal, gravity and filter membrane to separate oil products in different states such as free, emulsified and dissolved in the oil-water mixture from water. The filter membrane is the last thorough oil-water separation measure. The centrifugal and gravity separation in the previous stage is to reduce the working pressure of the filter membrane. In this way, oil-water separation can be achieved with large flow and high efficiency, especially for oil-water mixture with high oil content, the oil-water separation effect is better.

[0045] The oil-water separation system of the utility model requires two water pumps for inlet and outlet, and the gravity separation device requires compressed air, without other power energy consumption. The pressure of the water inlet pump is the height difference between the tangent inlet and the positioning oil outlet, and the pressure is relatively small. The water outlet pump is a water pump connected behind the filter membrane separation device, which provides a water permeability pressure difference between the two chambers. The pressure of the compressed air is sufficient to be greater than the pressure caused by the liquid height. The pressures of the two pumps and the compressed air are not large, and the energy consumption power is relatively small, so the goal of low energy consumption can be achieved.

Claims

1. An oil-water separation system, characterized in that: The invention comprises a centrifugal separation device, a gravity separation device and a filter membrane separation device which are connected by pipelines from front to back; the centrifugal separation device comprises an upper cone and a lower cone; the upper cone is provided with a positioning oil outlet (14); the diameter of the lower cone decreases downwards, the upper part of the lower cone is provided with a tangent inlet (11), and the lower part is provided with a buckle bowl outlet (12), and the buckle bowl outlet (12) is located between the inner wall and the center of the lower cone.

2. An oil-water separation system according to claim 1, characterized in that: A bottom ring (17) is arranged below the buckle bowl outlet (12), and an annular gap (19) is reserved between the bottom ring (17) and the inner wall of the lower cone. The bottom of the lower cone is a sludge outlet (13).

3. An oil-water separation system according to claim 2, characterized in that: The bottom ring (17) is in the shape of an upwardly convex spherical surface.

4. The oil-water separation system according to claim 2, characterized in that: An observation port (18) is arranged on the upper part of the sludge port (13); the observation port (18) is sealed by glass or transparent mica.

5. The oil-water separation system according to claim 1, characterized in that: A stirring device is arranged at the top of the upper cone, and a stirrer (110) of the stirring device extends into the position of the tangent inlet (11).

6. The oil-water separation system according to claim 1, characterized in that: A boiling plate (21) or a boiling pipe (27) is arranged at the bottom of the gravity separation device, and a drainage port is arranged below the boiling plate (21) or the boiling pipe (27); an air outlet (24) is arranged at the top of the gravity separation device; a float II (23) and a hose II (22) are arranged inside the gravity separation device, and an oil drainage port is designed on the float II (23), and the bottom opening of the float II (23) is connected to the middle oil drainage pipe through the hose II (22).

7. An oil-water separation system according to claim 6, characterized in that: The centrifugal separation device and the gravity separation device are combined; the float II (23) and the hose II (22) are arranged in the centrifugal separation device, and no positioning oil outlet (14) is arranged; and a boiling gas ring pipe (28) is arranged above the buckle bowl outlet (12).

8. An oil-water separation system according to claim 6 or 7, characterized in that: The filter membrane separation device is divided into a front chamber (31) and a rear chamber (34) by a filter membrane (32), and the filter membrane (32) is supported and fixed by a water-permeable plate (33); A float ball III (36) and a hose III (37) are arranged in the front cavity (31). The float ball III (36) is designed with an oil discharge port. The bottom opening of the float ball III (36) is connected to a middle oil discharge pipe through the hose III (37).

9. The oil-water separation system according to claim 8, characterized in that: The membrane separation devices are three in parallel.

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