Waste alkali liquor deoiling device

Abstract

The utility model discloses a waste lye deoiling device applied to the field of chemical engineering. The waste lye deoiling device comprises a rough filtration tank, a centrifugal tank, a fine filtration tank and a resin tank which are sequentially connected through pipelines. Quartz sand is placed in the rough filtration tank, an inner barrel of the centrifugal tank is arranged in the center of an outer tank body, an upper opening and a lower opening are formed in the tangential direction of a liquid inlet, the top and the bottom, a bubble breaking net is arranged above the upper opening, and a siphon is arranged on the upper portion in the outer tank body. A hollow filter element is inserted into a tank barrel of the fine filtering tank; and the resin tank is filled with resin. Or two fine filtration tanks are connected in parallel, and no less than three resin tanks are connected in series and in parallel. Various oil-water separation modes are combined, oil removal is thorough, and continuous oil removal is achieved.

Description

Technical Field

[0001] This utility model is applied in the chemical industry and relates to the treatment of waste alkali liquid, specifically an oil removal device for removing grease from waste alkali liquid. Background Technology

[0002] In the ethylene cracking process, acidic gases such as CO2 and H2S in the cracked gas are typically removed by alkaline washing. The waste alkaline solution generated during alkaline washing must undergo degreasing and desulfurization treatments to meet standards before being discharged. This waste alkaline solution contains not only alkaline inorganic salts such as NaOH, Na2CO3, and Na2S, but also a certain amount of oily substances, commonly known as "butter." This butter is formed during the alkaline washing process by the condensation of heavy components in the cracked gas and the polymerization of diene substances. The degreased waste alkaline solution can be recycled or further treated for desulfurization and purification.

[0003] There are many patents for oil-water separation devices, such as the CN215559128U oil removal device. Microbubble dissolved air water and oily wastewater are mixed in a hydrocyclone separator using differential swirling. Centrifugal force causes the oil to converge towards the center of the cyclone. Simultaneously, microbubbles adsorb suspended oil droplets and suspended solids, causing oil-water separation. The centrifugal force accelerates the convergence of oil droplets and bubbles towards the center of the cyclone. However, this type of device does not completely remove oil and cannot achieve complete oil-water separation. The CN217025420U oil-water separation device involves the mixed liquid entering a columnar cyclone chamber for centrifugal separation. Solid particles accumulate in a storage tube and then enter a coalescing filter and a separating filter. Water droplets gradually increase in size on the surface of the coalescing filter and settle due to gravity. The separating filter blocks the water droplets coalescing in the coalescing filter, preventing them from entering the separating filter with the separated oil. While this type of device removes oil relatively thoroughly, it is not suitable for removing large quantities of oil-water mixtures. CN210885656U describes an oil-water separation device. Oily raw water, after simple separation by sedimentation or centrifugation, undergoes acid-base neutralization. In a filter, oily suspended solids and some oil are retained by fiber filter media and enter a primary membrane separator. Under the separation action of a columnar oleophilic-hydrophobic membrane, water without dispersed or suspended oil permeates through the columnar membrane and enters an ultrasonic demulsifier. Light oil with a density less than water floats, while heavy oil with a density greater than water sinks. The water separated in the ultrasonic demulsifier is demulsified under the action of ultrasound and then sent to a secondary membrane separator, where it undergoes further separation by a columnar oleophilic-hydrophobic membrane. Although the oil removal principle of this device is simple, its oil removal effect depends on the penetration effect of the acid-base neutralization oleophilic-hydrophobic membrane. In the ethylene manufacturing field, there are few patents for oil removal from waste alkali liquid. Among them, CN117326755A describes a method and device for deep treatment of oily waste alkali liquid. In this device, the waste alkali liquid passes through a fiber coalescing section and a particle coalescing section sequentially in a shape coalescing unit to achieve oil-water separation. The fiber coalescing section is a fiber coalescing bed woven in an X- or Ω-shape using a combination of high-molecular-weight oleophilic fibers and metallic hydrophilic fibers; the particle coalescing section is a particle coalescing bed formed by the natural accumulation of oleophilic and hydrophilic particles with specific adsorption properties. CN202497742U describes a waste alkali oil-water separator and coalescer. The waste alkali liquid undergoes primary separation through inclined plate packing, secondary separation through a novel coalescing net, and tertiary separation through gravity settling. Oily substances are continuously impacted and demulsified by the arc-shaped sieve and inclined plate packing, accumulating and then adsorbed by the novel coalescing net, continuously coalescing into large oil droplets that are desorbed from the net. Finally, after a long period of gravity settling, the oily substances floating in the upper layer are discharged through the oil phase outlet at the top of the oil collection chamber, while the waste alkali liquid is discharged through the water phase outlet at the bottom of the cylinder. In addition, the experimental study on deep oil removal from ethylene waste alkaline solution employed a combination of quartz sand, polyacrylonitrile fiber felt filter membrane, and anion exchange resin for oil removal. This method had no impact on inorganic matter, and achieved an oil removal rate of over 90%. Quartz sand removed suspended solid particles and a small amount of colloids, while the polyacrylonitrile fiber felt filter membrane intercepted suspended fine particles, a large amount of colloids, and some large molecular hydrocarbon polymers. Through regeneration, it can be recycled.The anion exchange resin uses a strongly basic resin, and there are molecular bonds and van der Waals forces between the quaternary ammonium group and the benzene ring, which effectively adsorbs and removes dissolved oil. Utility Model Content

[0004] The technical problem solved by this utility model is to provide a waste alkali solution oil removal device that uses a combination of centrifugal oil removal, gravity oil removal, filtration oil removal and adsorption oil removal to achieve thorough oil removal.

[0005] The technical solution adopted in this utility model is as follows: The waste alkali liquid oil removal device of this utility model includes a coarse filter tank, a centrifuge tank, a fine filter tank, and a resin tank. Quartz sand is placed in the coarse filter tank to filter floating matter and solid impurities in the waste alkali liquid. An outlet is provided at the bottom of the coarse filter tank, which is connected to the inlet of the inner cylinder of the centrifuge tank via a transfer pump and pipeline, transporting the liquid waste alkali liquid to the centrifuge tank. The centrifuge tank includes an outer tank body and an inner cylinder body. The inner cylinder body is located at the center of the outer tank body, and a tangentially connected inlet is provided on the cylinder wall of the inner cylinder body. A lower opening is provided at the bottom of the inner cylinder body, and an upper opening is provided at the top; the upper opening is located on the centerline of the inner cylinder body, and a defoaming screen is provided above the upper opening; a siphon pipe is provided in the upper part of the inner cavity of the outer tank body, and a wastewater outlet is provided at the lower part. The centrifuge tank uses centrifugal separation and gravity separation to separate water-in-oil lipids, larger oil droplets, and oil droplets containing air bubbles from the waste alkali liquid, and transports the waste alkali water from the wastewater outlet pipeline to the wastewater inlet of the fine filter tank. The fine filter tank includes a tank cylinder and a hollow filter element inserted within the tank cylinder. The tank cylinder has an oil removal port and a wastewater inlet, with the oil removal port located at the top of the tank cylinder. The hollow inner cavity of the hollow filter element is connected to a water outlet. The fine filter tank filters out small oil droplets from the waste alkaline water, and the secondary alkaline water is transported from the outlet pipe to the inlet of the resin tank. The resin tank is filled with resin, and has an inlet at the top and an alkaline solution outlet at the bottom. The resin tank adsorbs and separates the oil-in-water emulsion and micro-droplets from the secondary alkaline water, and the alkaline water flows out from the alkaline solution outlet, completing the oil removal process for the waste alkaline water.

[0006] Furthermore, the size of the bubble-breaking net is not smaller than the size of the top opening, so as to achieve complete bubble breaking.

[0007] Furthermore, to ensure the flow and filtration effect of the waste alkali solution, the quartz sand is 40-100 mesh.

[0008] Furthermore, to prevent the quartz sand from flowing into the centrifuge tank, a filter screen with a mesh size of 120-150 is installed at the bottom of the quartz sand.

[0009] Furthermore, to ensure the operation of the fine filter canister during filter cartridge replacement, two fine filter canisters can be designed to be connected in parallel.

[0010] Furthermore, to ensure that resin regeneration and resin tank operation occur simultaneously, at least three resin tanks are designed to be connected in series and parallel. Each resin tank is equipped with an inlet valve and an outlet valve. The outlet of one resin tank is connected to the inlet of the next resin tank in sequence through branch valves and pipes, forming a circulating connection.

[0011] The beneficial effects of this invention are as follows: This invention uses a combination of multiple methods, including quartz sand filtration, filter cartridge filtration, centrifugal separation, gravity separation, and adsorption separation, to remove grease from waste alkaline solution, achieving thorough oil removal. One fine filter tank is used as a backup, and resin tanks are connected in series and parallel to achieve continuous oil removal. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the structure of Example 1;

[0013] Figure 2 This is a schematic diagram of the series-parallel structure of the resin tanks in Example 2;

[0014] Figure 3 This is a schematic elevation view of the resin tank series-parallel structure in Example 2;

[0015] Among them: 1-coarse filter tank, 2-centrifuge tank, 3-fine filter tank, 4-resin tank, 5-transfer pump;

[0016] 11-Inner hopper, 12-Quartz sand, 13-Outer cylinder, 14-Liquid outlet;

[0017] 21-Bubble-breaking net, 22-Siphon tube, 23-Upper opening, 24-Liquid inlet, 25-Outer tank, 26-Inner cylinder, 27-Lower opening, 28-Wastewater outlet;

[0018] 31-Tank cylinder, 32-Filter element, 33-Oil outlet, 34-Wastewater inlet, 35-Water outlet;

[0019] 41-Water inlet, 42-Resin, 43-Alkali outlet. Detailed Implementation

[0020] For the sake of brevity, the accompanying drawings illustrate the working principle of this utility model. The drawings mainly show the structure of this utility model. Components not shown in the drawings or whose structures are not detailed, such as manholes, level gauges, pressure gauges, level alarms, support components, defoaming nets, flow pumps, etc., as well as resin regeneration, are all existing technologies. Example

[0021] The waste alkali degreasing device in this embodiment is as follows: Figure 1 As shown, it includes a coarse filter tank 1, a centrifuge tank 2, a fine filter tank 3, a resin tank 4, etc., connected in sequence by pipes.

[0022] The coarse filter tank 1 includes an inner hopper 11 and an outer cylinder 13. The inner hopper 11 is fitted inside the outer cylinder, with an open top to collect waste alkaline solution. A filter screen of 120-150 mesh is installed at the bottom, and quartz sand 12 of 40-100 mesh is placed inside the inner hopper. The outer cylinder 13 has an open top to support the inner hopper, and a liquid outlet 14 is provided at the bottom. The liquid outlet 14 is connected to the liquid inlet 24 of the inner cylinder of the centrifuge tank through a transfer pump 5 and a pipeline.

[0023] Centrifuge tank 2 includes an outer tank body 25 and an inner cylinder body 26. The inner cylinder body 26 is located at the center of the outer tank body 25. A tangentially connected liquid inlet 24 is provided on the cylinder wall of the inner cylinder body. A lower opening 27 is provided at the bottom of the inner cylinder body, which is consistent with the inner diameter of the cylinder body. An upper opening 23 is provided at the top, located on the center line of the inner cylinder body. Above the upper opening, a bubble-breaking screen 21 is provided, the size of which is not smaller than that of the upper opening. A siphon pipe 22 is provided in the upper part of the inner cavity of the outer tank body 25, the opening of which is upward and higher than the bubble-breaking screen. A wastewater outlet 28 is provided in the lower part of the outer tank body 25.

[0024] The fine filter tank 3 includes a tank cylinder 31 and a filter element 32, which is hollow and inserted inside the tank cylinder 31. The tank cylinder 31 is equipped with an oil drain port 33 and a wastewater inlet 34. The wastewater inlet 34 is connected to the wastewater outlet 28 of the centrifuge tank. The oil drain port 33 is located at the top of the tank cylinder and is connected to an oil drain pipe, which is equipped with a valve. The hollow inner cavity of the filter element is connected to a water outlet 35, which is connected to the water inlet 41 of the resin tank 4 via a pipe.

[0025] The resin tank 4 is filled with resin 42, which is a strongly alkaline anion exchange resin. The upper part of the resin tank is provided with a water inlet 41, and the bottom is provided with an alkali outlet 43.

[0026] In this embodiment, the waste alkali solution flows from top to bottom through quartz sand 12 within the inner hopper 11 of the coarse filter tank, filtering out floating matter and solid impurities. The liquid waste alkali solution is then pumped from the outlet 14 at the bottom of the tank into the inner cylinder 26 of the centrifuge tank by a transfer pump. The liquid waste alkali solution enters the inner cylinder tangentially, creating a swirling flow. Centrifugal force centrifuges oil-in-water lipids, larger oil droplets, and oil droplets containing air bubbles to the center of the inner cylinder, where they float and flow out from the top opening 23. When oil droplets containing air bubbles pass through the bubble-breaking net 21, the bubbles are broken, and the oil floats upward under the buoyancy of the waste alkali solution, flowing out of the centrifuge tank through the siphon pipe 22. The waste alkali solution in the inner cylinder rotates downwards. After flowing out of the bottom opening, the space inside the outer tank increases, slowing the flow rate. Small oil droplets in the waste alkali solution collide and are adsorbed into larger droplets, which float upwards by gravity between the inner and outer cylinders and enter the oil. Waste alkaline water containing small oil droplets flows into the fine filter tank from wastewater outlet 28 at the bottom of the outer tank. The waste alkaline water is filtered through filter element 32, where the small oil droplets are blocked. The water containing oil-in-water enters the inner cavity of the filter element and flows into the resin tank from outlet 35. The small oil droplets blocked by the filter element gradually agglomerate and grow into larger droplets, floating to the upper part of the tank. After a certain amount is stored, it is discharged through the oil drain outlet 33 and oil drain pipe. The water reacts with the resin 42 in the resin tank, effectively removing the oil-in-water emulsion and micro-droplets, finally becoming alkaline water, which flows out from alkaline water outlet 43. The alkaline water becomes a completely de-oiled aqueous solution of the waste alkaline water, which can be sold as a product or used to prepare for subsequent treatment.

[0027] Notes: 1) The inner hopper inside the outer cylinder of the coarse filter tank is only for convenient replacement of the quartz. If two coarse filter tanks are connected in parallel, one can be used as a backup, and the quartz can be placed directly inside the coarse filter tank without using the inner hopper. 2) The liquid waste alkaline solution inside the inner cylinder of the centrifuge tank requires swirling power. A transfer pump should be installed on the connecting pipe between the two tanks. For other tanks, a transfer pump or gravity flow can be used, depending on the tank layout. 3) Filter cartridges need to be replaced after a certain period of use or after passing a certain amount of fluid. Insert-type cartridges facilitate quick replacement. 4) The resin can be reused after soaking regeneration. Soaking regeneration involves first soaking in a 3% hydrogen peroxide solution, then soaking in an alkaline ethanol mixture, and finally washing with water to restore the resin's oil removal capacity. 5) Waste alkaline solution is highly corrosive. Tanks, cylinders, filter screens, and defoaming screens should not be made of metal. Fiberglass, plastics, and other alkali-resistant materials are preferable. Example

[0028] In the above embodiments, there are issues with the replacement of quartz sand, filter elements, and resin. The inner hopper and quartz sand in the coarse filter tank can be quickly replaced, and one coarse filter tank can be used. The fine filter tank requires periodic filter element replacement; it is advisable to have one on standby. As the degreasing time increases, the degreasing capacity of the resin gradually decreases. To achieve the optimal degreasing effect and meet the needs of resin regeneration, the resin tanks should preferably be connected in series and parallel, as shown in the attached figure. Figure 2 and attached Figure 3 As shown.

[0029] In the attached diagram, A, B, and C represent three resin tanks. A1 and A2 are the inlet and outlet valves of resin tank A, respectively; B1 and B2 are the inlet and outlet valves of resin tank B, respectively; and C1 and C2 are the inlet and outlet valves of resin tank C, respectively. AB, BC, and CA are branch valves on the pipelines connecting the outlet of resin tank A to the inlet of resin tank B, the outlet of resin tank B to the inlet of resin tank C, and the outlet of resin tank C to the inlet of resin tank A, respectively. The three tanks are connected in series and parallel, requiring a total of nine valves.

[0030] Taking tanks A and B in series for oil removal and tank C for resin regeneration as an example, open valves A1, AB, and B2, and close the remaining valves. With all four valves connecting to tank C closed, resin regeneration can be performed independently. Alkali water flows from the inlet pipe through valve A1, tank A, valves AB, tank B, and valve B2, and enters the outlet pipe, achieving series oil removal for tanks A and B. When tank A needs regeneration, open valves B1, BC, and C2, and close the remaining valves. Alkali water flows from the inlet pipe through valve B1, tank B, valves BC, tank C, and valve C2, and enters the outlet pipe, achieving series oil removal for tanks B and C, and regeneration for tank A. Similarly, open valves C1, CA, and A2, and close the remaining valves. Alkali water flows from the inlet pipe through valve C1, tank C, valve CA, tank A, and valve A2, and enters the outlet pipe, achieving series oil removal for tanks C and A, and regeneration for tank B.

[0031] In this embodiment, three resin tanks are used: two tanks are connected in series for oil removal, and one tank is used for resin regeneration. Series oil removal enhances the oil removal effect, while parallel use improves oil removal or regeneration efficiency, achieving uninterrupted continuous oil removal and meeting the need for continuous oil removal of large quantities of waste alkaline solution.

[0032] Note: Resin regeneration time is typically long, usually longer than the resin working time. To achieve continuous degreasing, multiple resin tanks can be connected in series or parallel, such as four tanks. Figure 2 and attached Figure 3 A new tank, D, is added between tanks C and A. An inlet valve D1 and an outlet valve D2 are added to tank D. The valve CA is replaced with valves CD and DA, which are respectively valves on the pipelines connecting the outlet of tank C to the inlet of tank D, and the outlet of tank D to the inlet of tank A. When the two tanks connected in series are working, the resin in the other two tanks is regenerated. Following this principle, five resin tanks can also be connected in series and parallel to increase the adjustment time for resin regeneration.

[0033] The structural features of the resin tanks connected in series and parallel in this embodiment are as follows: the number of tanks is not less than 3, each tank is equipped with an inlet valve and an outlet valve, and the outlet of one tank is connected to the inlet of the next tank in sequence through a branch valve and a pipeline, thereby forming a loop connection. The number of valves is 3 times the number of tanks.

[0034] This invention addresses the removal of oil from waste alkaline solutions using different methods depending on its form. Oil-in-water emulsions, large oil droplets, and oil droplets encased in air bubbles are removed by centrifugation and gravity in a centrifuge tank. Small oil droplets are removed using a fine filter cartridge in a fine filter tank. Water-in-oil emulsions and micro-droplets are removed by adsorption using a strongly alkaline anion exchange resin in a resin tank, ultimately resulting in oil-free alkaline solution with thorough oil removal. One fine filter tank is used as a backup, and the resin tanks are connected in series and parallel to meet the requirements for continuous oil removal, facilitating filter cartridge replacement and resin regeneration.

Claims

1. A waste lye oil removal device, characterized by: It comprises a coarse filter tank (1), a centrifugal tank (2), a fine filter tank (3) and a resin tank (4). The quartz sand (12) is placed in the coarse filter tank (1), and a liquid outlet (14) is arranged at the bottom of the quartz sand (12); the liquid outlet (14) is connected to the liquid inlet (24) of the inner cylinder of the centrifugal tank through a conveying pump (5) and a pipeline; The centrifugal tank (2) comprises an outer tank body (25) and an inner cylinder (26), the inner cylinder (26) is arranged at the center of the outer tank body (25), a tangential liquid inlet (24) is arranged on the cylinder wall of the inner cylinder (26); a lower opening (27) is arranged at the bottom of the inner cylinder (26), and an upper opening (23) is arranged at the top of the inner cylinder (26); the upper opening (23) is located on the center line of the inner cylinder, and a bubble breaking net (21) is arranged above the upper opening (23); a siphon (22) is arranged at the upper part of the inner cavity of the outer tank body (25), and a wastewater outlet (28) is arranged at the lower part of the outer tank body (25); The fine filter tank (3) comprises a tank cylinder (31) and a hollow filter core (32) inserted into the tank cylinder (31), an oil removal port (33) and a wastewater inlet (34) are arranged on the tank cylinder (31), and the oil removal port (33) is located at the top of the tank cylinder (31); the hollow inner cavity of the hollow filter core (32) is connected to a water outlet (35); The resin tank (4) is filled with resin (42), and a water inlet (41) is arranged at the upper part of the resin tank, and an alkali outlet (43) is arranged at the bottom of the resin tank; The wastewater outlet (28) is connected to the wastewater inlet (34), the water outlet (35) and the water inlet (41) through a pipeline.

2. The waste lye deoiling device of claim 1, wherein: The size of the bubble breaking net (21) is not less than the size of the upper opening (23).

3. The waste lye deoiling device of claim 1, wherein: The quartz sand (12) is 40-100 mesh.

4. The waste lye deoiling device of claim 3, wherein: A filter screen is arranged at the bottom of the quartz sand (12), and the filter screen is 120-150 mesh.

5. The waste lye deoiling device of claim 1, wherein: Two fine filter tanks (3) are connected in parallel.

6. The waste lye deoiling device of claim 1, wherein: Not less than three resin tanks (4) are connected in series and in parallel.

7. The waste lye deoiling device of claim 6, wherein: Each resin tank (4) is provided with an inlet valve and an outlet valve, the outlet of the previous resin tank (4) is sequentially connected to the inlet of the next resin tank (4) through a branch valve and a pipeline, so as to form a circulating communication.

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