Binary hydrophobic-hydrophilic particles deep bed oil removal process and device coupling coalescence and adsorption

Abstract

The application provides a coalescence-adsorption coupled binary hydrophilic-hydrophobic particle deep bed oil removal process and device, and the process comprises the following steps: S1, mixed liquid mixing and adsorption; S2, first coalescence separation of the mixed liquid; S3, second coalescence separation of the mixed liquid; and S4, recycling of emulsified oil containing DOM and adsorbent. The process of the application realizes efficient purification of oil-containing sewage containing DOM and emulsified oil through the steps of adsorbent dispersion mixing and two-stage binary hydrophilic-hydrophobic particle coalescence separation, in combination with a special device; the mixing effect of the adsorbent and the sewage can be strengthened, the DOM adsorption and emulsified oil demulsification efficiency can be improved, the adsorbent recycling and water phase purification can be realized at the same time, and the problems of incomplete treatment and low efficiency of existing oil removal technologies on multi-form pollutants are solved.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, specifically to a deep-bed oil removal process and apparatus for binary hydrophilic and hydrophobic particles coupled with coalescence-adsorption, applicable to oily wastewater treatment scenarios containing multiple forms of pollutants such as emulsified oil and dissolved organic matter (DOM). Background Technology

[0002] Oily wastewater widely originates from industries such as petroleum extraction, chemical production, and machinery processing. It not only contains emulsified oil but also often includes various oil-soluble pollutants (DOMs). These pollutants are highly stable and difficult to remove completely using conventional treatment technologies. Existing oil removal processes mostly employ single-method coalescence or adsorption, which suffers from the following technical drawbacks: low mixing efficiency, insufficient adsorbent utilization, and incomplete separation of fine oil droplets. Furthermore, they cannot simultaneously achieve pollutant removal and adsorbent recycling, resulting in high treatment costs and difficulty in meeting effluent quality standards.

[0003] CN220449867U discloses a coalescing oil separation device. The main body of the device is a separator, with an inlet on the upper side wall, an oil phase outlet at the top, and a water outlet at the bottom. Inside the separator, a distributor and a coalescing filter module are assembled sequentially from top to bottom. The coalescing filter module adopts a double-layer composite structure, consisting of a hydrophilic / hydrophobic particle coalescing module and a hydrophilic / hydrophobic fiber coalescing module from top to bottom. Oily wastewater enters through the inlet on the upper side wall of the separator, is evenly dispersed by the distributor, and flows sequentially through the hydrophilic / hydrophobic particle coalescing module and the hydrophilic / hydrophobic fiber coalescing module. Oil droplets float to the top of the separator under buoyancy and are discharged from the oil phase outlet, while the treated wastewater flows out from the bottom outlet. However, this device has the following technical defects after long-term operation: the coalescing filter module is prone to clogging due to oil film adhesion, requiring periodic shutdown for cleaning or replacement; and no module regeneration and reuse scheme is mentioned.

[0004] CN109179776B discloses an oily wastewater treatment device. This device adopts a cuboid box structure, divided by internal partitions into sequentially connected oil-water separating chambers, demulsification chambers, and adsorption chambers. Oily wastewater flows sequentially through each chamber under gravity without additional power. The wastewater first undergoes preliminary filtration of impurities through a filter screen below the top inlet of the oil-water separating chamber. Then, it passes through an internal oil flotation collector to separate and output recyclable oil, while a perforated sludge collection pipe at the bottom simultaneously collects sludge. After the effluent from the oil-water separating chamber flows into the demulsification chamber, a demulsifier is added through a dosing port, and the mixture is thoroughly mixed with the wastewater by a tubular static mixer to achieve demulsification. Finally, the effluent from the demulsification chamber flows into the adsorption chamber, where the emulsified oil is removed by adsorption using sawdust packing. The treated wastewater is then discharged from the top outlet of the adsorption chamber. This device solves the problems of impurity interference, difficulty in recovering floating oil, and incomplete removal of emulsified oil in traditional oily wastewater treatment, but it has the following technical defects: the adsorption capacity of the sawdust filler is limited, it needs to be replaced regularly and no regeneration scheme is mentioned; the demulsifying agent needs to be continuously replenished and cannot be recycled, resulting in high long-term operation and maintenance costs.

[0005] CN119612673A discloses an extraction-coalescence coupled waste alkali solution oil removal device and method. It achieves efficient oil removal through a series of modules including a Y-type filter, a micro-mixing extractor, and a two-stage axial coalescing filter, via extraction dispersion, graded coalescence, and sedimentation separation. It also features backwashing without shutdown and a compact structure. However, it has the following technical drawbacks: it requires a large amount of equipment and occupies a large area; the long settling time limits the waste alkali solution treatment efficiency; and it fails to achieve the recycling of the extractant, resulting in low economic efficiency.

[0006] CN118724330A discloses a waste alkaline solution oil removal device and method combining extraction coupled with horizontal fluidized bed coalescing filtration. The device integrates multiple modules in a horizontal tank. Waste alkaline solution and extractant are micro-dispersed and intensified before being sequentially separated through two stages of fluidized bed coalescing filtration and fiber coalescing. Online self-cleaning is achieved through steam fluidization. This technology simultaneously removes multiple forms of oil and suspended solids, operates continuously, has a small footprint, and achieves an oil removal efficiency of up to 99.28%, making it suitable for high-viscosity oily wastewater. However, it has the following technical drawbacks: high precision requirements for core components; fluidized bed cleaning requires a large amount of low-pressure steam, resulting in high costs; and the extractant is limited to specific types, making it uneconomical for low-viscosity oily wastewater.

[0007] Therefore, how to design a deep-bed oil removal process and device for binary hydrophilic and hydrophobic particles that can couple the functions of coalescence and adsorption and efficiently treat pollutants of various forms has become an urgent problem to be solved. Summary of the Invention

[0008] To address the problems existing in the prior art, the present invention provides a deep bed oil removal process and apparatus for binary hydrophilic and hydrophobic particles with coalescence-adsorption coupling, so as to solve at least one of the above-mentioned technical problems.

[0009] The technical solution of this invention is: a deep-bed oil removal process using binary hydrophilic and hydrophobic particles coupled by coalescence-adsorption, comprising the following steps:

[0010] S1, Mixed adsorption of the mixed solution:

[0011] ① Oily wastewater containing pollutants in various forms, such as DOM and emulsified oil, flows sequentially through an oily wastewater storage tank and an oily wastewater transfer pump into an adsorbent disperser;

[0012] ② The oily adsorbent in the adsorbent storage tank is pressurized by the adsorbent delivery pump at 0.2-0.4 MPa and delivered to the adsorbent dispersion nozzle of the adsorbent disperser. It is dispersed into the oily wastewater as small-diameter micro-droplets to form a mixture of oily wastewater and adsorbent. The mixture enters the micro-mixer.

[0013] S2, First coalescence and separation of the mixture:

[0014] ① The mixture enters the top inlet of the first-stage hydrophilic-hydrophobic particle coalescing separator from the micro mixer. The mixture flows from top to bottom in the first-stage hydrophilic-hydrophobic particle coalescing separator. Through the coalescence and interception of oleophilic and hydrophilic particles, the adsorbent in the mixture adheres to the surface of the oleophilic particles, expanding the contact area with the mixture, realizing DOM adsorption and emulsified oil demulsification. At the same time, oil droplets are captured and coalesced by the oleophilic particles.

[0015] ② Hydrophilic particles intercept suspended solids in the mixture, achieving preliminary oil-water separation;

[0016] ③ Suspended solids and solid particles in the mixed liquid are filtered into the particle bed and removed by backwashing after the interception capacity is reached;

[0017] S3, Second coalescence and separation of the mixture:

[0018] ① The mixture flowing out of the first-stage hydrophilic-hydrophobic particle coalescing separator flows into the top inlet of the second-stage hydrophilic-hydrophobic particle coalescing separator through the base at the bottom of the first-stage hydrophilic-hydrophobic particle coalescing separator. The mixture flows from top to bottom in the second-stage hydrophilic-hydrophobic particle coalescing separator, achieving fine coalescing and separation of residual micro oil droplets in the aqueous phase.

[0019] ② Hydrophilic particles intercept suspended solids in the mixture, achieving preliminary oil-water separation;

[0020] ③ Suspended solids and solid particles in the mixed liquid are filtered into the particle bed and removed by backwashing after the interception capacity is reached;

[0021] ④ The aqueous phase is discharged, and flows out through the aqueous phase outlet at the bottom of the two-stage hydrophilic and hydrophobic particle agglomeration separator and the bottom of the base in sequence;

[0022] S4. Recycling of emulsified oil containing DOM and adsorbent:

[0023] ① The emulsified oil containing DOM and adsorbent is discharged through the base oil outlet below the first-stage hydrophilic-hydrophobic particle coalescing separator and the base oil outlet below the second-stage hydrophilic-hydrophobic particle coalescing separator, and then transported to the adsorbent storage tank.

[0024] ② The emulsified oil containing DOM and adsorbent is transported to the adsorbent spraying and mixing module to disperse and mix with the oily wastewater, thus realizing the recycling of the adsorbent.

[0025] The process of this invention achieves efficient purification of oily wastewater containing DOM and emulsified oil through steps of adsorbent dispersion and mixing, and two-stage binary hydrophilic and hydrophobic particle aggregation and separation, combined with a dedicated device. It can enhance the mixing effect between the adsorbent and the wastewater, improve the adsorption of DOM and the demulsification efficiency of emulsified oil, and realize the recycling of adsorbent and water phase purification. It solves the technical defects of existing oil removal technologies, such as incomplete treatment and low efficiency of multi-form pollutants. The wood chip packing has a limited adsorption capacity, needs to be replaced regularly, and no regeneration plan is mentioned. The demulsifying agent needs to be continuously replenished and cannot be recycled, resulting in high long-term operation and maintenance costs.

[0026] The technical solution of this invention is: a deep-bed oil removal device for binary hydrophilic-hydrophobic particles coupled with coalescence-adsorption, comprising an oily wastewater storage tank and an adsorbent circulation module. The oily wastewater storage tank is sequentially connected to an oily wastewater transfer pump, an adsorbent injection and mixing module, and a hydrophilic-hydrophobic particle bed coalescence-adsorption module via pipelines. The adsorbent injection and mixing module includes an adsorbent disperser and a micro-mixer. The hydrophilic-hydrophobic particle bed coalescence-adsorption module includes a primary hydrophilic-hydrophobic particle coalescence separator and a secondary hydrophilic-hydrophobic particle coalescence separator.

[0027] The adsorbent circulation module includes an adsorbent delivery pump and an adsorbent storage tank. The inlet of the adsorbent storage tank is connected to the oil outlet of the hydrophilic-hydrophobic particle bed coalescing-adsorption module. The outlet of the adsorbent storage tank is connected to the adsorbent disperser through the adsorbent delivery pump. The outlet of the adsorbent disperser is connected to the primary hydrophilic-hydrophobic particle coalescing separator and the secondary hydrophilic-hydrophobic particle coalescing separator in sequence through a micro-mixer. Purified water is discharged from the bottom of the secondary hydrophilic-hydrophobic particle coalescing separator.

[0028] This invention employs an adsorbent storage tank for storing and collecting adsorbents, and an adsorbent spray mixing module with embedded nozzles to disperse the adsorbent, significantly increasing the contact area. A two-stage particle coalescing separator separates oil and water droplets, removing DOM (oil-derived organic matter) and emulsified oil, thus purifying oily wastewater. The adsorbent flows into the adsorbent storage tank through the oil outlet below the coalescing separator support layer and auxiliary pipelines. The adsorbent is recycled via an adsorbent delivery pump, the storage tank, and the auxiliary pipelines. This simple structure achieves a unique combination of efficient oil removal and adsorbent recycling, overcoming the limitations of fluidized bed cleaning (requiring large amounts of low-pressure steam and incurring high costs) and the limitations of extractants (requiring only specific types and being uneconomical for low-viscosity oily wastewater).

[0029] The present invention has the following beneficial effects:

[0030] 1. By using an adsorbent spray dispersion and variable diameter mixing channel design, the contact area between the adsorbent and the wastewater is increased, resulting in a high DOM removal rate; the two-stage hydrophilic and hydrophobic particle agglomeration separator provides graded treatment, with an emulsified oil removal rate of over 95%, solving the problem of synergistic pollution from multiple forms of pollutants.

[0031] 2. Constructing a closed-loop adsorbent recycling system reduces the amount of adsorbent used in the DOM removal process, significantly reducing treatment costs and the risk of secondary pollution, thus meeting green and environmental protection requirements;

[0032] 3. The droplet size of the adsorbent can be adjusted by the jet pressure difference and the nozzle diameter. The particle bed parameters (oil-to-water ratio, porosity) are optimized for different pollutant morphologies, making it suitable for oily wastewater with fluctuating DOM and emulsified oil content.

[0033] 4. This invention achieves deep separation through a secondary hydrophilic and hydrophobic particle oil removal structure that enhances agglomeration through dispersion and mixing. It has advantages such as good oil removal effect, high separation efficiency, simple device, long backwashing cycle, green and environmentally friendly, and wide applicability. It can be widely used in oily wastewater treatment scenarios containing emulsified oil and dissolved organic matter in various forms of pollutants during petrochemical production processes. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the installation structure of the present invention.

[0035] Figure 2 This is a schematic diagram of the binary hydrophilic-hydrophobic particle aggregation module of the present invention.

[0036] In the diagram: 1. Oily wastewater storage tank; 2. Oily wastewater transfer pump; 3. Adsorbent storage tank; 4. Adsorbent transfer pump; 5. Adsorbent disperser; 6. Micro mixer; 7. Primary hydrophilic-hydrophobic particle coalescing separator; 8. Secondary hydrophilic-hydrophobic particle coalescing separator; 9. Pressure gauge; 10. Flow meter; 11. Oil droplet; 12. DOM (Oil Doppler Object); 13. Hydrophilic particle; 14. Oleophilic particle. Detailed Implementation

[0037] The present invention will now be further described with reference to the accompanying drawings.

[0038] See Figure 1-2 The structures, proportions, and sizes illustrated in the accompanying drawings are merely for illustrative purposes and to aid those skilled in the art in understanding and reading the invention. They are not intended to limit the scope of the invention and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and purpose of the invention, should still fall within the scope of the technical content disclosed in this invention. Furthermore, the terms "upper," "lower," "left," "right," "middle," and "one" used in this specification are merely for clarity and not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention's implementation.

[0039] Example 1: A deep-bed oil removal device for binary hydrophilic and hydrophobic particles with coalescence-adsorption coupling, referenced Figure 1 The system includes an oily wastewater storage tank 1 and an adsorbent circulation module. The oily wastewater storage tank 1 is connected in sequence to an oily wastewater transfer pump 2, an adsorbent injection and mixing module, and a hydrophilic-hydrophobic particle bed coalescence-adsorption module via pipelines. The adsorbent injection and mixing module includes an adsorbent disperser 5 and a micro-mixer 6. The hydrophilic-hydrophobic particle bed coalescence-adsorption module includes a primary hydrophilic-hydrophobic particle coalescence separator 7 and a secondary hydrophilic-hydrophobic particle coalescence separator 8.

[0040] The adsorbent circulation module includes an adsorbent delivery pump 4 and an adsorbent storage tank 3. The inlet of the adsorbent storage tank 3 is connected to the oil outlet of the hydrophilic-hydrophobic particle bed coalescence-adsorption module. The outlet of the adsorbent storage tank 3 is connected to the adsorbent dispersion nozzle embedded in the adsorbent disperser 5 through the adsorbent delivery pump 4. The outlet of the adsorbent disperser 5 is connected to the primary hydrophilic-hydrophobic particle coalescence separator 7 and the secondary hydrophilic-hydrophobic particle coalescence separator 8 in sequence through the micro mixer 6. Purified water is discharged from the bottom of the secondary hydrophilic-hydrophobic particle coalescence separator 8. This invention employs an adsorbent storage tank for storing and collecting adsorbents, and an adsorbent spray mixing module with embedded nozzles to disperse the adsorbent, significantly increasing the contact area. A two-stage particle coalescing separator separates oil and water droplets, removing DOM (oil-derived organic matter) and emulsified oil, thus purifying oily wastewater. The adsorbent flows into the adsorbent storage tank through the oil outlet below the coalescing separator support layer and auxiliary pipelines. The adsorbent is recycled via an adsorbent delivery pump, the storage tank, and the auxiliary pipelines. This simple structure achieves a unique combination of efficient oil removal and adsorbent recycling, overcoming the limitations of fluidized bed cleaning (requiring large amounts of low-pressure steam and incurring high costs) and the limitations of extractants (requiring only specific types and being uneconomical for low-viscosity oily wastewater).

[0041] Example 2: Based on Example 1, the hydrophilic-hydrophobic particle bed coalescing-adsorption module includes an inlet, an oil phase outlet, and an aqueous phase outlet. The inlet of the primary hydrophilic-hydrophobic particle coalescing separator 7 is connected to the outlet of the micro-mixer 6, and the aqueous phase outlet of the primary hydrophilic-hydrophobic particle coalescing separator 7 is connected to the inlet of the secondary hydrophilic-hydrophobic particle coalescing separator 8. The oil phase outlets of both the primary and secondary hydrophilic-hydrophobic particle coalescing separators 7 and 8 are connected to the adsorbent storage tank 3. This invention employs a two-stage binary hydrophilic-hydrophobic particle coalescing separator composed of a primary and a secondary hydrophilic-hydrophobic particle coalescing separator, which improves DOM adsorption and emulsified oil demulsification efficiency.

[0042] Example 3: Based on Example 1, the adsorbent disperser 5 has an oily wastewater inlet on its left side, which is connected to the outlet of the oily wastewater transfer pump 2. An adsorbent dispersion nozzle is installed inside the adsorbent disperser 5, connected to the outlet of the adsorbent transfer pump 4. A flow meter 10 is installed on the outlet pipe of the adsorbent transfer pump 4. This invention uses an embedded adsorbent dispersion nozzle to achieve adsorbent dispersion, greatly increasing the contact area.

[0043] Example 4: Based on Example 3, the primary hydrophilic-hydrophobic particle coalescing separator 7 and the secondary hydrophilic-hydrophobic particle coalescing separator 8 have the same structure. The primary hydrophilic-hydrophobic particle coalescing separator 7 is installed vertically and includes a shell and a base below the shell. The shell contains a particle bed and a support layer arranged from top to bottom. The top of the shell has a mixed liquid inlet and the bottom of the shell has a mixed liquid outlet. The interior of the base is connected to the interior of the shell. Pressure gauges 9 are installed on the upper part of the shell and the upper part of the base, respectively. The left side of the base has a backwash inlet and the top of the base has a backwash outlet. This invention employs a primary hydrophilic-hydrophobic particle coalescing separator and a secondary hydrophilic-hydrophobic particle coalescing separator with identical structures. The primary hydrophilic-hydrophobic particle bed is composed of stacked small-diameter oleophilic and hydrophilic particles with small interparticle gaps, resulting in a high adsorbent adhesion probability and high adsorption-demulsification efficiency. It enhances oil-water phase separation by utilizing the coalescing and separation effect of oleophilic and hydrophilic particles. The secondary hydrophilic-hydrophobic particle bed is composed of stacked large-diameter oleophilic and hydrophilic particles with a high proportion of oleophilic particles. It also enhances oil-water phase separation by utilizing the coalescing and separation effect of oleophilic and hydrophilic particles. A support layer is installed at the bottom of the particle bed to support the bed. A backwash inlet is located on the left side of the base, and a backwash outlet is located at the top of the base, which solves the technical defects of easy clogging due to oil film adhesion, requiring periodic shutdown for cleaning or replacement.

[0044] Example 5: Based on Example 4, the micro-mixer 6 adopts a tank body with a variable-diameter mixing channel inside. The oily wastewater entering the micro-mixer 6 has an emulsified oil content of no more than 10% and a total DOM content of no more than 2%. The adsorbent is one or more of the following: process raw materials or finished products (alkanes, ketones, etc.). The volume ratio of adsorbent to oily wastewater is 1:50 to 1:5. This invention utilizes a variable-diameter mixing channel within the micro-mixer. Turbulence is generated through changes in the channel cross-section, enhancing the mixing uniformity of the adsorbent microdroplets and wastewater, thus improving adsorption efficiency and increasing the mass transfer efficiency between DOM and the adsorbent.

[0045] Example 6: Based on Example 4, the outlet of the adsorbent storage tank 3 is connected to the adsorbent dispersion nozzle via the adsorbent delivery pump 4. The outlet of the adsorbent dispersion nozzle extends into the tank body of the adsorbent disperser 5 and intersects with the outlet pipe of the aqueous supply unit. This invention achieves adsorbent recycling and aqueous phase purification by connecting the outlet of the adsorbent storage tank to the adsorbent dispersion nozzle via the adsorbent delivery pump.

[0046] Example 7: Based on Example 4, the adsorbent dispersion droplet size dispersed by the adsorbent dispersion nozzle is 20–300 µm. The droplet size is adjusted by the spray pressure difference of 0.2–0.4 MPa and the nozzle diameter of 0.5–5 mm. This invention uses an adsorbent dispersion nozzle to disperse the adsorbent, greatly increasing the contact area.

[0047] Example 8: Based on Example 4, the particle bed in the first-stage hydrophilic-hydrophobic particle coalescing separator 7 has a stacking ratio of oleophilic particles to hydrophilic particles of 0.5:1 to 2:1, a particle size of 1 to 4 mm, a contact angle between the oleophilic particles and oil in water not exceeding 60°, and a porosity of 30% to 50%. This invention employs a particle bed with a stacking ratio of oleophilic particles to hydrophilic particles of 0.5:1 to 2:1, a particle size of 1 to 4 mm, a contact angle between the oleophilic particles and oil in water not exceeding 60°, and a porosity of 30% to 50%. This bed is composed of small-diameter oleophilic and hydrophilic particles, resulting in small particle gaps, compact vertical gaps, narrow microchannels, a high adsorbent adhesion probability, and high adsorption-demulsification efficiency. The oleophilic particles have coalescing-demulsification function, while the oleophobic particles maintain high bed permeability. The coalescing and separation effect of the oleophilic and hydrophilic particles enhances the separation of the oil and water phases.

[0048] Example 9: Based on Example 4, the particle bed in the secondary hydrophilic-philic particle coalescing separator 8 has a stacking ratio of oleophilic to hydrophilic particles of 2:1 to 5:1, a particle size of 0.5 to 2 mm, a contact angle between the oleophilic particles and oil in water not exceeding 60°, and a porosity of 30% to 40%. This invention employs a particle bed with a stacking ratio of oleophilic to hydrophilic particles of 2:1 to 5:1, a particle size of 0.5 to 2 mm, a contact angle between the oleophilic particles and oil in water not exceeding 60°, and a porosity of 30% to 40%. This bed is composed of large-diameter oleophilic-hydrophilic particles, with a high proportion of oleophilic particles. The coalescing and separation effect of oleophilic and hydrophilic particles enhances the separation of the oil and water phases, allowing for deep coalescing and separation of fine oil droplets.

[0049] Example 10: A deep-bed oil removal process using binary hydrophilic and hydrophobic particles with coalescence-adsorption coupling, comprising the following steps:

[0050] S1, Mixed adsorption of the mixed solution:

[0051] ① Oily wastewater containing pollutants such as DOM and emulsified oil flows sequentially through oily wastewater storage tank 1 and oily wastewater transfer pump 2 into adsorbent disperser 5;

[0052] ② The oily adsorbent in the adsorbent storage tank 3 is pressurized by the adsorbent delivery pump 4 at 0.2-0.4 MPa and delivered to the adsorbent dispersion nozzle of the adsorbent disperser 5. It is sprayed into the adsorbent disperser 5 in the form of micro-droplets and dispersed into the oily wastewater as small-diameter micro-droplets, forming a mixture of oily wastewater and adsorbent. The mixture enters the micro-mixer 6. This invention uses a variable diameter mixing channel to enhance turbulence, so as to achieve full mixing of adsorbent and wastewater and initially complete the DOM adsorption and emulsified oil contact.

[0053] S2, First coalescence and separation of the mixture:

[0054] ① The mixture enters the top inlet of the first-stage hydrophilic-hydrophobic particle coalescing separator 7 from the micro mixer 6. The mixture flows from top to bottom in the first-stage hydrophilic-hydrophobic particle coalescing separator 7. Through the coalescence and interception of oleophilic and hydrophilic particles, the adsorbent in the mixture adheres to the surface of the oleophilic particles, expanding the contact area with the mixture, realizing DOM adsorption and emulsified oil demulsification. At the same time, oil droplets are captured and coalesced by the oleophilic particles.

[0055] ② Hydrophilic particles intercept suspended solids in the mixture, achieving preliminary oil-water separation;

[0056] ③ Suspended solids and solid particles in the mixed liquid are filtered into the particle bed and removed by backwashing after the interception capacity is reached;

[0057] S3, Second coalescence and separation of the mixture:

[0058] ① The mixture flowing out of the first-stage hydrophilic-hydrophobic particle coalescing separator 7 flows into the top inlet of the second-stage hydrophilic-hydrophobic particle coalescing separator 8 through the base at the bottom of the first-stage hydrophilic-hydrophobic particle coalescing separator 7. The mixture flows from top to bottom in the second-stage hydrophilic-hydrophobic particle coalescing separator 8, achieving fine coalescing and separation of residual micro oil droplets in the aqueous phase.

[0059] ② Hydrophilic particles intercept suspended solids in the mixture, achieving preliminary oil-water separation;

[0060] ③ Suspended solids and solid particles in the mixed liquid are filtered into the particle bed and removed by backwashing after the interception capacity is reached;

[0061] ④ The aqueous phase is discharged, and flows out through the aqueous phase outlet at the bottom of the two-stage hydrophilic and hydrophobic particle agglomeration separator 8 and the bottom of the base in sequence;

[0062] S4. Recycling of emulsified oil containing DOM and adsorbent:

[0063] ① The emulsified oil containing DOM and adsorbent is discharged through the base oil outlet below the first-stage hydrophilic-hydrophobic particle coalescing separator 7 and the base oil outlet below the second-stage hydrophilic-hydrophobic particle coalescing separator 8, and then transported to the adsorbent storage tank 3.

[0064] ② The emulsified oil containing DOM and adsorbent is transported to the adsorbent spraying and mixing module to disperse and mix with the oily wastewater, realizing the recycling of the adsorbent. The process of this invention achieves efficient purification of oily wastewater containing DOM and emulsified oil through the steps of adsorbent dispersion and mixing, and two-stage binary hydrophilic and hydrophobic particle agglomeration and separation, combined with a dedicated device; it can enhance the mixing effect between adsorbent and wastewater, improve the adsorption of DOM and the demulsification efficiency of emulsified oil, and realize the recycling of adsorbent and water phase purification at the same time. It solves the technical defects of existing oil removal technologies, such as incomplete treatment of multiple pollutants and low efficiency; the limited adsorption capacity of wood chip filler, which requires regular replacement and no regeneration scheme is mentioned; and the need for continuous replenishment of demulsifying agent, which fails to realize recycling and leads to high long-term operation and maintenance costs.

[0065] Example 11: A factory conducted an oily wastewater purification test using the process and apparatus of the present invention. Preliminary investigation revealed that the wastewater generated during the dyeing, finishing and leather fatliquoring processes contained a large amount of emulsified oil. At the same time, the dyes and dyeing auxiliaries contained various phenols and benzene compounds. These multi-form pollutants pose a great threat to the environment.

[0066] Oily wastewater storage tank 1 specifications: 100L volume, connected to the factory wastewater outlet;

[0067] Adsorbent storage tank 3 specifications: pressure vessel, volume 20L;

[0068] Adsorbent disperser 5 specifications: approximately 300mm long and 50mm wide, with an adsorbent dispersion nozzle size of 0.3mm and an adsorbent droplet D50 of 15μm;

[0069] Micromixer 6 Specifications: To improve mixing intensity, an SV-type static mixer is selected, approximately 200mm long and 20mm wide;

[0070] Specifications of the first-stage hydrophilic / hydrophobic particle agglomeration separator: length approximately 500mm, diameter approximately 20mm, particle bed height approximately 400mm, particle size between 0.5-1mm, oleophilic / hydrophilic particle mixture stacked in a 1:1 ratio, average particle gap approximately 0.1mm;

[0071] Two-stage hydrophilic / hydrophobic granular oil separator, specification 8: length approximately 500mm, diameter approximately 20mm, granular bed height approximately 400mm, granular size between 1-2mm, oleophilic / hydrophilic granules mixed and stacked in a 1:1 ratio, average particle gap approximately 0.3mm;

[0072] All liquid connection pipes have an inner diameter of 8mm;

[0073] The treatment capacity of this experiment was 0.5 m³ / h. The adsorbent used was n-hexane, a common byproduct in petrochemicals, at a rate of 0.2 m³ / h, i.e., the oily wastewater and adsorbent were mixed and extracted at a ratio of 1:5. The oily wastewater contained approximately 0.7% emulsified oil and approximately 0.1% DOM (poly(ethylene oxide) compounds, such as phenols and benzene series compounds), as well as a small amount of large-diameter dispersed oil droplets. After the device had been running stably for a certain period of time, water samples were taken from the inlet and outlet, and the treatment effect was evaluated using an infrared oil analyzer. The oil removal efficiency reached over 98%, and the total DOM removal efficiency reached 80%. The backwashing cycle of the equipment was approximately 15 days of continuous operation. The pressure difference between the upper and lower pressure gauges of the first-stage hydrophilic-hydrophobic particle oil separator 7 and its base reached 0.2 MPa. Backwashing was performed using 2 m³ / h of water at 30°C for 30 minutes to achieve particle regeneration.

[0074] In specific implementation, refer to Figure 2 Oily wastewater is transported from oily wastewater storage tank 1 to the left inlet of adsorbent disperser 5 via oily wastewater transfer pump 2. Simultaneously, oily adsorbent in adsorbent storage tank 3 is pressurized by adsorbent transfer pump 4 and sprayed into adsorbent disperser 5 in the form of micro-droplets through adsorbent dispersion nozzles, where it is initially mixed with the wastewater. The mixture then enters micro-mixer 6, where turbulence generated by the variable-diameter mixing channel achieves uniform mixing of the adsorbent and wastewater, initially completing the adsorption of DOM and the contact wetting of emulsified oil. The mixture flows through the outlet of micro-mixer 6 and into the top inlet of the primary hydrophilic-hydrophobic particle agglomeration separator 7, flowing downwards through the particle bed: the surface of the oleophilic particles 14 adsorbs the adsorbent, increasing the contact area between the adsorbent and the mixture, further adsorbing residual DOM 12; simultaneously, emulsified oil droplets 11 agglomerate and grow on the surface of the oleophilic particles 14, while the hydrophilic particles 13 intercept suspended matter in the mixture, initially... The separated aqueous phase flows out from the bottom of the primary hydrophilic-hydrophobic particle coalescing separator 7 and enters the secondary hydrophilic-hydrophobic particle coalescing separator 8. The aqueous phase separated by the primary hydrophilic-hydrophobic particle coalescing separator 7 flows into the top inlet of the secondary hydrophilic-hydrophobic particle coalescing separator 8 and flows from top to bottom through a particle bed with a high oleophilic ratio: the oleophilic particles 14 efficiently capture residual fine oil droplets 11, causing them to further coalesce and separate from the aqueous phase; at the same time, the residual DOM 12 is completely adsorbed by the adsorbent, and the finally purified aqueous phase flows out from the aqueous phase outlet at the bottom base of the secondary hydrophilic-hydrophobic particle coalescing separator 8. The adsorbent that has adsorbed DOM and emulsified oil is discharged from the oil drain port at the base below the two-stage hydrophilic-hydrophobic particle coalescing separator and flows back to the adsorbent storage tank 3 through the pipeline. The adsorbent in the adsorbent storage tank 3 is pressurized again by the adsorbent delivery pump 4 and then delivered to the adsorbent dispersion nozzle of the adsorbent disperser 5 to mix with the newly entered oily wastewater, completing the closed-loop circulation of the adsorbent.

[0075] The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A deep-bed oil removal device for binary hydrophilic and hydrophobic particles coupled with agglomeration-adsorption, comprising an oily wastewater storage tank (1) and an adsorbent circulation module, characterized in that: The oily wastewater storage tank (1) is connected in sequence to the oily wastewater transfer pump (2), the adsorbent injection mixing module, and the hydrophilic-hydrophobic particle bed coalescence-adsorption module via pipelines. The adsorbent injection mixing module includes an adsorbent disperser (5) and a micro mixer (6). The hydrophilic-hydrophobic particle bed coalescence-adsorption module includes a primary hydrophilic-hydrophobic particle coalescence separator (7) and a secondary hydrophilic-hydrophobic particle coalescence separator (8). The adsorbent circulation module includes an adsorbent delivery pump (4) and an adsorbent storage tank (3). The inlet of the adsorbent storage tank (3) is connected to the oil outlet of the hydrophilic-hydrophobic particle bed coalescence-adsorption module. The outlet of the adsorbent storage tank (3) is connected to the adsorbent dispersion nozzle embedded in the adsorbent disperser (5) through the adsorbent delivery pump (4). The outlet of the adsorbent disperser (5) is connected to the first-stage hydrophilic-hydrophobic particle coalescence separator (7) and the second-stage hydrophilic-hydrophobic particle coalescence separator (8) in sequence through the micro mixer (6). Purified water is discharged from the bottom of the second-stage hydrophilic-hydrophobic particle coalescence separator (8).

2. The deep-bed oil removal device for binary hydrophilic and hydrophobic particles with coalescence-adsorption coupling according to claim 1, characterized in that: The hydrophilic-hydrophobic particle bed coalescence-adsorption module includes an inlet, an oil phase outlet, and an aqueous phase outlet; the inlet of the primary hydrophilic-hydrophobic particle coalescence separator (7) is connected to the outlet of the micro-mixer (6), and the aqueous phase outlet of the primary hydrophilic-hydrophobic particle coalescence separator (7) is connected to the inlet of the secondary hydrophilic-hydrophobic particle coalescence separator (8); the oil phase outlets of the primary hydrophilic-hydrophobic particle coalescence separator (7) and the secondary hydrophilic-hydrophobic particle coalescence separator (8) are both connected to the adsorbent storage tank (3).

3. The deep-bed oil removal device for binary hydrophilic and hydrophobic particles with coalescence-adsorption coupling according to claim 2, characterized in that: The adsorbent disperser (5) has an oily wastewater inlet on its left side, which is connected to the outlet of the oily wastewater conveying pump (2); the adsorbent dispersion nozzle is connected to the outlet of the adsorbent conveying pump (4), and a flow meter (10) is installed on the outlet pipeline of the adsorbent conveying pump (4).

4. The deep-bed oil removal device for binary hydrophilic and hydrophobic particles with coalescence-adsorption coupling according to claim 3, characterized in that: The primary hydrophilic-hydrophobic particle coalescing separator (7) and the secondary hydrophilic-hydrophobic particle coalescing separator (8) have the same structure. The primary hydrophilic-hydrophobic particle coalescing separator (7) is installed vertically. The primary hydrophilic-hydrophobic particle coalescing separator (7) includes a shell and a base below the shell. The shell is provided with a particle bed and a support layer from top to bottom. The top of the shell is provided with a mixed liquid inlet and the bottom of the shell is provided with a mixed liquid outlet. The interior of the base is connected to the interior of the shell. Pressure gauges (9) are installed on the upper part of the shell and the upper part of the base, respectively. The left side of the base is provided with a backwash inlet and the top of the base is provided with a backwash outlet.

5. The deep-bed oil removal device for binary hydrophilic and hydrophobic particles with coalescence-adsorption coupling according to claim 4, characterized in that: The micro mixer (6) is a tank with a variable diameter mixing channel inside. The oily wastewater entering the micro mixer (6) has an emulsified oil content of no more than 10% and a total DOM content of no more than 2%. The adsorbent is one or more of the following: alkanes, lipids, ketones, or finished products. The volume ratio of the adsorbent to the oily wastewater is 1:50 to 1:

5.

6. The deep-bed oil removal device for binary hydrophilic and hydrophobic particles with coalescence-adsorption coupling according to claim 4, characterized in that: The outlet of the adsorbent storage tank (3) is connected to the adsorbent dispersion nozzle via the adsorbent delivery pump (4). The outlet of the adsorbent dispersion nozzle extends into the tank of the adsorbent disperser (5) and intersects with the outlet pipe of the water phase supply unit.

7. The deep-bed oil removal device for binary hydrophilic and hydrophobic particles with coalescence-adsorption coupling according to claim 4, characterized in that: The adsorbent dispersion droplets dispersed by the adsorbent dispersion nozzle have a particle size of 20–300 µm. The particle size of the adsorbent dispersion droplets is adjusted by the spray pressure difference (0.2–0.4 MPa) and the nozzle diameter (0.5–5 mm).

8. The deep-bed oil removal device for binary hydrophilic and hydrophobic particles with coalescence-adsorption coupling according to claim 4, characterized in that: The particle bed in the primary hydrophilic-hydrophobic particle agglomeration separator (7) has a stacking ratio of oleophilic particles to hydrophilic particles of 0.5:1 to 2:1, a particle size of 1 to 4 mm, a contact angle between the oleophilic particles and oil in water of no more than 60°, and a porosity of 30% to 50%.

9. The deep-bed oil removal device for binary hydrophilic and hydrophobic particles with coalescence-adsorption coupling according to claim 4, characterized in that: The particle bed in the secondary hydrophilic-hydrophobic particle agglomeration separator (8) has a stacking ratio of oleophilic particles to hydrophilic particles of 2:1 to 5:1, a particle size of 0.5 to 2 mm, a contact angle between the oleophilic particles and oil in water of no more than 60°, and a porosity of 30% to 40%.

10. A deep-bed oil removal process using binary hydrophilic-hydrophobic particles coupled with agglomeration-adsorption, characterized in that: Includes the following steps: S1, Mixed adsorption of the mixed solution: ① Oily wastewater containing DOM and emulsified oil and other pollutants in various forms flows into the adsorbent disperser (5) through the oily wastewater storage tank (1) and the oily wastewater transfer pump (2); ② The oily adsorbent in the adsorbent storage tank (3) is pressurized by the adsorbent delivery pump (4) at 0.2-0.4 MPa and delivered to the adsorbent dispersion nozzle of the adsorbent disperser (5). The adsorbent is dispersed into the oily wastewater as small-diameter micro-droplets to form a mixture of oily wastewater and adsorbent. The mixture enters the micro-mixer (6). S2, First coalescence and separation of the mixture: ① The mixture enters the top inlet of the first-stage hydrophilic-hydrophobic particle coalescing separator (7) from the micro mixer (6). The mixture flows from top to bottom in the first-stage hydrophilic-hydrophobic particle coalescing separator (7). Through the coalescence and interception of lipophilic and hydrophilic particles, the adsorbent in the mixture adheres to the surface of the lipophilic particles, expanding the contact area with the mixture, realizing DOM adsorption and emulsified oil demulsification. At the same time, the oil droplets are captured and coalesced by the lipophilic particles. ② Hydrophilic particles intercept suspended solids in the mixture, achieving preliminary oil-water separation; ③ Suspended solids and solid particles in the mixed liquid are filtered into the particle bed and removed by backwashing after the interception capacity is reached; S3, Second coalescence and separation of the mixture: ① The mixture flowing out of the first-stage hydrophilic-hydrophobic particle coalescing separator (7) flows into the top inlet of the second-stage hydrophilic-hydrophobic particle coalescing separator (8) through the base at the bottom of the first-stage hydrophilic-hydrophobic particle coalescing separator (7). The mixture flows from top to bottom in the second-stage hydrophilic-hydrophobic particle coalescing separator (8) to achieve fine coalescing and separation of residual micro oil droplets in the aqueous phase. ② Hydrophilic particles intercept suspended solids in the mixture, achieving preliminary oil-water separation; ③ Suspended solids and solid particles in the mixed liquid are filtered into the particle bed and removed by backwashing after the interception capacity is reached; ④ The aqueous phase is discharged, and the aqueous phase flows out through the bottom of the two-stage hydrophilic and hydrophobic particle agglomeration separator (8) and the bottom of the base. S4. Recycling of emulsified oil containing DOM and adsorbent: ① The emulsified oil containing DOM and adsorbent is discharged through the base oil outlet below the first-stage hydrophilic particle coalescing separator (7) and the base oil outlet below the second-stage hydrophilic particle coalescing separator (8), and transported to the adsorbent storage tank (3). ② The emulsified oil containing DOM and adsorbent is transported to the adsorbent spraying and mixing module to disperse and mix with the oily wastewater, thus realizing the recycling of the adsorbent.

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