Highly-emulsified oil-water enhanced separation system and process method

Abstract

The invention relates to a highly emulsified oil-water enhanced separation system and process method.The system comprises a pretreatment device used for receiving oily sewage and removing large-particle suspended solids and floating oil in the oily sewage; the efficient blocking and oil removing device comprises an efficient blocking and oil removing tank, a plurality of blocking and oil removing assemblies used for breaking and capturing emulsified oil drops are arranged in the efficient blocking and oil removing tank, and a water inlet of the efficient blocking and oil removing device is connected with a water outlet of the pretreatment device; a water inlet of the deep adsorption oil removal device is connected with a water outlet of the efficient interception oil removal device, and the deep adsorption oil removal device is used for removing most dissolved oil in the wastewater; the self-cleaning backwashing device is connected with the deep adsorption and oil removal device through a multi-way valve and is used for realizing alternate and directional backwashing of different blocking and oil removal assemblies in the efficient blocking and oil removal device; and the regeneration device is connected with the deep adsorption oil removal device and is used for carrying out circulating flushing regeneration on the deep adsorption oil removal device.

Description

Technical Field

[0001] This invention relates to a highly emulsified oil-water enhanced separation system and process, belonging to the field of industrial wastewater treatment technology. Background Technology

[0002] In industrial production processes such as petrochemicals, machining, and metallurgy, large quantities of oily wastewater with complex compositions and high treatment difficulty are generated. This type of wastewater typically contains not only floating and dispersed oil, but also a large amount of emulsified oil formed due to the presence of surfactants, and even dissolved oil. In particular, highly emulsified oily wastewater has extremely small oil droplet sizes (usually <20μm), carries surface charges, and has a stable system, making it difficult to effectively separate using traditional methods such as gravity separation, flotation, and ordinary filtration.

[0003] Currently, membrane separation technologies (such as ultrafiltration and microfiltration) are widely used in the treatment of emulsified oily wastewater. However, they suffer from problems such as easy membrane fouling, rapid flux decline, the need for frequent chemical cleaning, short membrane life, and high operating costs. Furthermore, conventional demulsifiers are ineffective for oily wastewater under high salinity conditions and may introduce secondary pollution. Adsorption is used as an advanced treatment method, but the adsorption packing material is difficult to regenerate after saturation, often resulting in high operating costs due to its single-use nature. Therefore, developing an oil-water enhanced separation system and process that can efficiently demulsify, resist fouling, operate stably for long periods, and regenerate the adsorbent has become a pressing technical challenge in this field. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a highly emulsified oil-water enhanced separation system and process. This system is highly adaptable to harsh water quality with high emulsification and high salinity, and is particularly suitable for treating industrial oily wastewater that is difficult to treat with traditional methods. It also shows great advantages on offshore platforms where space is limited and environmental protection requirements are stringent.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A highly emulsified oil-water enhanced separation system includes: A pretreatment device is used to receive oily wastewater and remove large suspended solids and floating oil from the oily wastewater; A high-efficiency interception and oil removal device includes a high-efficiency interception and oil removal tank, wherein the high-efficiency interception and oil removal tank is provided with a plurality of interception and oil removal components for breaking and capturing emulsified oil droplets, and the inlet of the high-efficiency interception and oil removal device is connected to the outlet of the pretreatment device. A deep adsorption oil removal device, the inlet of which is connected to the outlet of the high-efficiency interception oil removal device, is used to remove most of the dissolved oil in the wastewater. The self-cleaning backwashing device is connected to the deep adsorption oil removal device through a multi-way valve, and is used to realize the alternating and directional backwashing of different oil removal components in the high-efficiency blocking oil removal device. A regeneration device is connected to the deep adsorption oil removal device and is used to perform cyclic flushing and regeneration of the deep adsorption oil removal device.

[0006] The highly emulsified oil-water enhanced separation system, preferably, includes a pretreatment device that is a self-cleaning filter or an air flotation device, the type of which depends on the quality of the oily wastewater; and / or, The filter particle size of the pretreatment device is no greater than 50 μm.

[0007] In the aforementioned highly emulsified oil-water enhanced separation system, preferably, the oil-blocking and removal component is a hydrophilic-oleophobic component, and several of the oil-blocking and removal components are arranged in an array to form a ring.

[0008] Preferably, in the highly emulsified oil-water enhanced separation system, the oil-blocking and removal component is a sheet-like metal substrate structure with mesh-like pleats. Specifically, the oil-blocking and removal component is made of a metal-based material modified with hydrophilic and hydrophobic active components, exhibiting superhydrophilic and superoleophobic properties.

[0009] Preferably, in the highly emulsified oil-water enhanced separation system, the specific surface area of ​​the oil-blocking and removing component is above 500 m² / m³.

[0010] In the aforementioned highly emulsified oil-water enhanced separation system, preferably, the sieve aperture of the oil-blocking and removal component is 1000~8000 mesh. The specific aperture can be determined based on the oil particle size in the wastewater. This component forms a stable hydration layer in the water through its superhydrophilic properties, effectively blocking oil droplet adhesion. Simultaneously, its large specific surface area and fine pore size efficiently break down and capture emulsified oil droplets through collision, sieving, and aggregation.

[0011] Preferably, in the highly emulsified oil-water enhanced separation system, the deep adsorption oil removal device is composed of multiple deep adsorption columns connected in series or in parallel.

[0012] Preferably, in the highly emulsified oil-water enhanced separation system, the deep adsorption column is filled with an oleophilic and hydrophobic packing material, which includes modified activated carbon or hydrophobic modified polymer resin.

[0013] In the aforementioned highly emulsified oil-water enhanced separation system, preferably, the packing height of the deep adsorption column is 2 / 3 to 4 / 5 of the column height. The packing material deeply removes residual trace amounts of emulsified oil and soluble oils through multiple actions such as adsorption, collision, and interception.

[0014] Preferably, in the highly emulsified oil-water enhanced separation system, the regeneration device 5 consists of a selective heater and a tank. High-temperature hot water (typically 85-90°C) is generated by heating water to circulate and regenerate the saturated deep adsorption oil removal device. The high-temperature hot water reduces the viscosity of the oil and disrupts the adsorption force between the packing material and the oil, thereby desorbing the adsorbed oil and restoring the adsorption capacity of the packing material.

[0015] A second aspect of the present invention provides a process method for the above-mentioned highly emulsified oil-water enhanced separation system, comprising the following steps: Oily wastewater is first treated by the pretreatment device to remove large suspended solids and floating oil, thus reducing the load on the subsequent main treatment unit. The pretreated wastewater then enters the high-efficiency interception and oil removal device, where, under an operating pressure of 0.2 MPa to 0.3 MPa and a hydraulic retention time of 5 to 10 minutes, most of the emulsified oil is removed. The effluent from the high-efficiency interception oil removal device enters the deep adsorption oil removal device. Under a low operating pressure of 0.05MPa to 0.1MPa, the hydraulic retention time is 15 to 20 minutes, which is used to deeply remove dissolved oils from the water, so that the oil content of the final effluent meets the discharge standards. When the adsorption capacity of the deep adsorption oil removal device reaches saturation, the deep adsorption oil removal device is regenerated by hot water at 85 to 90°C generated by the regeneration device to restore its adsorption performance. During system operation, by controlling the opening, closing, and flow direction of the multi-way valves in the self-cleaning backwashing device, the different oil-blocking and removing components within the high-efficiency oil-blocking and removing device can be backwashed alternately and in a directional manner. This washes away contaminants adhering to the surface of the components, restoring their filtration performance and ensuring long-term stable operation of the system.

[0016] The system of this invention is suitable for treating highly emulsified, highly saline and oily wastewater with an oil content of 80~800mg / L, a suspended solids content of 100~1000mg / L, and a conductivity of 5000~50000μS / cm.

[0017] The present invention has the following advantages due to the adoption of the above technical solutions: 1. High-efficiency demulsification and deep purification: The system adopts a multi-stage synergistic process of "pretreatment (impurity removal) + high-efficiency interception (demulsification and deemulsification of oil) + deep adsorption (removal of dissolved oil)" to remove oil in different forms step by step, resulting in high purification depth and good effluent quality.

[0018] 2. Anti-pollution and long-cycle operation: The high-efficiency oil blocking and removal components adopt super-hydrophilic-super-oleophobic modification and combined with a pleated structure, which greatly reduces oil pollution. Combined with array arrangement and directional backwashing function, it realizes online cleaning and uninterrupted operation, significantly extending the cleaning cycle and service life.

[0019] 3. Resource utilization and low cost: The deep adsorption system is equipped with a hot water regeneration system, which realizes the recycling of adsorption packing material, avoids the high costs and hazardous waste disposal problems caused by frequent replacement of packing material, and reduces operating costs.

[0020] 4. High adaptability: The system is highly adaptable to harsh water quality with high emulsification and high salinity, and is particularly suitable for treating industrial oily wastewater that is difficult to treat with traditional methods. It shows great advantages, especially on offshore platforms with limited space and stringent environmental protection requirements.

[0021] 5. Automation and Compactness: The system features a modular design, a small footprint, and can achieve fully automatic operation (including backwashing and regeneration) through PLC control, making it ideal for unattended or space-constrained applications. Attached Figure Description

[0022] Figure 1 The process flow diagram of the highly emulsified oil-water enhanced separation system provided by the present invention; Figure 2 This is a schematic diagram of the structure of the high-efficiency oil blocking and removal component provided by the present invention; The attached figures are labeled as follows: 1-Pretreatment device; 2-High-efficiency interception and oil removal device; 3-Deep adsorption and oil removal device; 4-Self-cleaning backwashing device; 5-Regeneration device. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention are described clearly and completely below. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0024] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," "third," "fourth," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect.

[0025] For ease of description, spatial relative terms may be used in the text to describe the relationship of one element or feature relative to another element or feature as shown in the figure. These relative terms include, for example, "inside," "outside," "middle," "outer," "below," "above," etc. Such spatial relative terms are intended to include different orientations of the device in use or operation, other than those depicted in the figure.

[0026] Currently, membrane separation technologies (such as ultrafiltration and microfiltration) are widely used in the treatment of emulsified oily wastewater. However, they suffer from problems such as easy membrane fouling, rapid flux decline, the need for frequent chemical cleaning, short membrane life, and high operating costs. Furthermore, conventional demulsifiers are ineffective for oily wastewater under high salinity conditions and may introduce secondary pollution. Adsorption is used as an advanced treatment method, but the adsorption packing material is difficult to regenerate after saturation, often resulting in high operating costs due to its single-use nature. Therefore, developing an oil-water enhanced separation system and process that can efficiently demulsify, resist fouling, operate stably for long periods, and regenerate the adsorbent has become a pressing technical challenge in this field.

[0027] Based on the above-mentioned technical problems, the present invention provides a highly emulsified oil-water enhanced separation system and process method. This system has strong adaptability to harsh water quality with high emulsification and high salinity, and is particularly suitable for treating industrial oily wastewater that is difficult to treat by traditional methods. It shows great advantages, especially on offshore platforms with limited space and stringent environmental protection requirements.

[0028] like Figure 1 As shown, the highly emulsified oil-water enhanced separation system of the present invention includes: a pretreatment device 1 for receiving oily wastewater and removing large suspended solids and floating oil from the oily wastewater; a high-efficiency interception and removal device 2, including several interception and removal components for breaking down and capturing emulsified oil droplets, the inlet of the high-efficiency interception and removal device 2 being connected to the outlet of the pretreatment device 1; a deep adsorption oil removal device 3, the inlet of which is connected to the outlet of the high-efficiency interception and removal device 2, for removing most of the dissolved oil in the wastewater; a self-cleaning backwashing device 4, connected to the deep adsorption oil removal device 3 via a multi-way valve, for realizing the alternating and directional backwashing of different interception and removal components in the high-efficiency interception and removal device 2; and a regeneration device 5, connected to the deep adsorption oil removal device 3, for circulating flushing and regenerating the deep adsorption oil removal device 3.

[0029] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0030] Example 1 The treatment involves processing oily production water from an oilfield. The water quality is as follows: oil content ~500 mg / L, suspended solids ~600 mg / L, conductivity ~35000 μS / cm, and severe emulsification. The wastewater first enters a self-cleaning filter (50 μm filtration accuracy) to remove most of the suspended solids and some floating oil. The pretreated effluent enters a high-efficiency interception and oil removal tank at 0.25 MPa pressure. The tank contains eight sets of pleated superhydrophilic-superoleophobic stainless steel mesh membrane components (specific surface area ~600 m² / m³, pore size approximately 3000 mesh), with a hydraulic retention time of approximately 8 minutes. During this stage, over 95% of the emulsified oil is removed. Every 8 hours, the self-cleaning backwashing device 4 automatically initiates a backwashing program, switching between multiple valves to perform high-pressure water backwashing on one set of components for 2 minutes, sequentially washing all components in turn. After efficient oil removal, the effluent enters one of the deep adsorption columns (with packing material filling to 3 / 4 of the tank height) under a pressure of 0.08 MPa, with a hydraulic retention time of approximately 18 minutes, further adsorbing and removing dissolved oil and trace amounts of emulsified oil. When the oil content in the effluent from the deep adsorption column approaches the discharge standard limit, the system switches to another adsorption column. For saturated adsorption columns, 88°C hot water is pumped into the regeneration system and circulated for 2 hours to regenerate the packing material.

[0031] After treatment by this system, the final effluent oil content is consistently below 3 mg / L and suspended solids are below 5 mg / L, meeting national discharge standards.

[0032] Example 2 This embodiment is a specific application on an offshore oil platform. The implementation case adopts a highly integrated skid-mounted design to meet the requirements of compactness, automation and reliability of equipment in the narrow space of offshore platforms.

[0033] The production water from an offshore platform exhibits significant quality fluctuations, with oil content ranging from 150 to 600 mg / L, suspended solids from 200 to 800 mg / L, and chloride ion concentration approximately 15,000 mg / L. Furthermore, the water is highly emulsified and stable due to injection and production operations. The platform's incoming water first enters a self-cleaning filter, effectively removing approximately 90% of suspended solids and most of the floating oil, protecting subsequent core units. The pretreated effluent then enters a high-efficiency oil-blocking and removal device under a pressure of 0.28 MPa. This device is filled with a superhydrophilic-superoleophobic corrugated metal mesh membrane component with a specific surface area of ​​up to 700 m² / m³ and a pore size of 5000 mesh, with a hydraulic retention time of approximately 6 minutes. In this high-salt environment, the component's superhydrophilic properties make its hydration layer more stable, resulting in excellent demulsification and reducing the oil content of the effluent to below 20 mg / L. The backwashing process employs dual control using differential pressure triggering and time protection. When the pressure difference across the component reaches 0.15 MPa, or every 12 hours, the backwashing procedure is automatically initiated to ensure the system always operates within its high-efficiency range. The effluent from the high-efficiency oil removal device 2 enters two parallel deep adsorption columns filled with high-efficiency hydrophobic polymeric resin packing. At a pressure of 0.06 MPa, the hydraulic retention time is approximately 15 minutes, and the oil content in the effluent is consistently below 5 mg / L, meeting the most stringent marine discharge requirements. When one adsorption column becomes saturated, the system automatically switches to the standby column. The saturated column is then regenerated using 90°C hot water generated by the regeneration system. The desorbed concentrated oil-water mixture is collected and returned to the platform's main process treatment system, achieving internal waste disposal without secondary pollution.

[0034] This invention employs a multi-stage synergistic process of "pretreatment (impurity removal) + high-efficiency interception (demulsification and deemulsification of oil) + deep adsorption (removal of dissolved oil)" to remove oil in different forms step by step, resulting in high purification depth and good effluent quality. The system features high integration, high separation efficiency, stable operation, and the ability to regenerate key components.

[0035] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A highly emulsified oil-water enhanced separation system, characterized in that, include: Pretreatment device (1) is used to receive oily wastewater and remove large particulate suspended solids and floating oil from the oily wastewater; The high-efficiency interception and oil removal device (2) includes a high-efficiency interception and oil removal tank. The high-efficiency interception and oil removal tank is equipped with a number of interception and oil removal components for breaking and capturing emulsified oil droplets. The inlet of the high-efficiency interception and oil removal device (2) is connected to the outlet of the pretreatment device (1). The deep adsorption oil removal device (3) has its inlet connected to the outlet of the high-efficiency interception oil removal device (2) to remove most of the dissolved oil in the wastewater. The self-cleaning backwashing device (4) is connected to the deep adsorption oil removal device (3) through a multi-way valve, and is used to realize the alternating and directional backwashing of different blocking oil removal components in the high-efficiency blocking oil removal device (2); The regeneration device (5) is connected to the deep adsorption oil removal device (3) and is used to perform cyclic flushing and regeneration of the deep adsorption oil removal device (3).

2. The highly emulsified oil-water enhanced separation system according to claim 1, characterized in that, The pretreatment device (1) is a self-cleaning filter or an air flotation device; and / or, The filter particle size of the pretreatment device (1) is no greater than 50 μm.

3. The highly emulsified oil-water enhanced separation system according to claim 1, characterized in that, The oil-blocking and oil-removing component is a hydrophilic-oleophobic component, and several of the oil-blocking and oil-removing components are arranged in an array to form a ring.

4. The highly emulsified oil-water enhanced separation system according to claim 3, characterized in that, The oil-blocking and degreasing component has a sheet-like metal substrate structure with mesh-like pleats.

5. The highly emulsified oil-water enhanced separation system according to claim 4, characterized in that, The specific surface area of ​​the oil-blocking and degreasing component is above 500 m² / m³.

6. The highly emulsified oil-water enhanced separation system according to claim 5, characterized in that, The screening aperture of the oil removal component is 1000~8000 mesh.

7. The highly emulsified oil-water enhanced separation system according to claim 1, characterized in that, The deep adsorption oil removal device (3) is composed of multiple deep adsorption columns connected in series or in parallel.

8. The highly emulsified oil-water enhanced separation system according to claim 7, characterized in that, The deep adsorption column is filled with an oleophilic and hydrophobic filler, which includes modified activated carbon or hydrophobic modified polymer resin.

9. The highly emulsified oil-water enhanced separation system according to claim 8, characterized in that, The packing height of the packing material in the deep adsorption column is 2 / 3 to 4 / 5 of the height of the adsorption column.

10. A process method for a highly emulsified oil-water enhanced separation system according to any one of claims 1-9, characterized in that, Includes the following steps: Oily wastewater is first treated by the pretreatment device (1) to remove large particulate suspended solids and floating oil from the wastewater. The pretreated wastewater enters the high-efficiency interception and oil removal device (2), where it is hydraulically retained for a period of time under a certain operating pressure to remove most of the emulsified oil. The effluent from the high-efficiency blocking oil removal device (2) enters the deep adsorption oil removal device (3). Under a certain operating pressure, the water is hydraulically retained for a period of time to deeply remove dissolved oils from the water, so that the final effluent oil content meets the discharge standards. When the adsorption capacity of the deep adsorption oil removal device (3) reaches saturation, the hot water generated by the regeneration device (5) regenerates the deep adsorption oil removal device (3) to restore its adsorption performance. During system operation, by controlling the opening and closing and flow direction of the multi-way valve in the self-cleaning backwashing device (4), the different blocking and oil removal components in the high-efficiency blocking and oil removal device (2) can be backwashed in turn and in a directional manner.

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