A heavy oil wastewater separation process and device regulated by nano-micro powder

Abstract

This invention, belonging to the field of wastewater treatment technology, provides a process and apparatus for separating heavy oil wastewater using nanopowder. The nanopowder is uniformly added to the surface of the medium bed of a microchannel separator. The nanopowder is hydrophobic particles with a particle size of 0.1 to 50 μm and is selected from one or more of PP, PS, PE, or PVC. The ratio of the added nanopowder mass to the total mass of heavy oil in the heavy oil wastewater to be treated is 1:(1-200). This separation process significantly improves the oil removal efficiency of heavy oil wastewater, is environmentally friendly, has low energy consumption, and is easy to promote and implement.

Description

Technical Field

[0001] The present invention belongs to the technical field of wastewater treatment, and in particular relates to a heavy oil wastewater separation process and device regulated by nano-micro powder. Background Art

[0002] The production processes of polyolefins, fine chemicals, and other equipment often generate large amounts of wastewater containing heavy oil. This wastewater has complex organic components, high viscosity, high flash point, and high pour point. Currently, these processes are commonly used for treatment, including gravity sedimentation, centrifugal separation, flotation, coagulation, and membrane separation. However, these processes are generally plagued by oil adhesion, significantly affecting the separation device's throughput and continuous operational stability. There is an urgent need to develop a separation process that is resistant to clogging, requires minimal or no chemical agents, and consumes low energy to achieve efficient separation of heavy oil wastewater. To address these issues, scholars and engineers at home and abroad have conducted extensive technical research.

[0003] CN212102226U discloses a closed pretreatment device for refinery wastewater. This device uses a fluidized bed to remove floating oil and suspended solids, followed by a coalescer for further demulsification, coalescence, and separation of the emulsion, thereby reducing secondary pollution. However, this treatment process is primarily targeted at treating emulsified oily wastewater and lightly oily wastewater; heavy oil wastewater requires preliminary pretreatment before it can be treated.

[0004] The applicant in this case previously proposed a heterojunction microchannel separation method and device for oily wastewater, with patent publication number CN113277597A. This technical solution is to separate suspended matter and oil pollutants in oily wastewater through heterojunction microchannel separation, and to enhance the desorption of oil and sludge on the surface of medium particles through cyclonic rotation and ultimately achieve the regeneration of bed medium particles; however, this method mainly focuses on achieving demulsification of oily wastewater, and its oil removal efficiency is limited; when the oil concentration in the wastewater to be treated is high, effective oil removal cannot be achieved.

[0005] CN103289732A discloses a centrifugal heavy oil treatment system. The system uses a mixing and separation unit, specifically gravity-differential separation to purify the heavy oil. A three-phase centrifuge is used to separate solid particles, a small amount of oil, and water from wastewater. However, the treatment device requires the addition of a demulsifier, resulting in high energy consumption.

[0006] Therefore, in order to achieve effective oil removal of oily wastewater, especially oily wastewater with a high oil concentration, it is very necessary to design an environmentally friendly, low-energy and easy-to-implement oily wastewater separation process. Summary of the Invention

[0007] Based on the above situation, the present invention provides a heavy oil wastewater separation process and device regulated by nano-powder, which can purify heavy oil wastewater with more environmentally friendly technical means, lower energy consumption and more efficient oil removal effect.

[0008] To achieve the above object, the technical solution of the present invention is as follows:

[0009] A process for separating heavy oil wastewater using nanopowder-regulated materials, wherein the heavy oil wastewater is separated using a microchannel separator provided with a medium bed, wherein the medium particles in the medium bed are composite particles consisting of oleophilic and hydrophobic particles and hydrophilic and oleophobic particles, and the surface of the medium bed is uniformly doped with nanopowder, wherein the nanopowder is hydrophobic particles with a particle size of 0.1 to 50 μm and is selected from one or more of PP, PS, PE, or PVC, and the ratio of the total mass of the added nanopowder to the total mass of heavy oil in the heavy oil wastewater to be treated is 1:(1-200); the heavy oil wastewater to be treated enters the microchannel separator, first contacts the nanopowder, and is then treated by the medium bed to obtain purified water after deoiling.

[0010] The present invention is further configured such that the particle size of the nanopowder is 0.5-20 μm; more preferably 1.0-20 μm, such as 1.0-5 μm, 5-10 μm, 10-15 μm or 15-20 μm.

[0011] The present invention is further configured such that the ratio of the total mass of the added nanopowder to the total mass of heavy oil in the heavy oil wastewater to be treated is 1:(1-20); preferably 1:(1-10).

[0012] The present invention is further configured such that the ratio of the total mass of the added nanopowder to the total mass of the heavy oil in the heavy oil wastewater to be treated is 1:(1-5), for example, 1:1, 1:2, 1:3, 1:4 or 1:5.

[0013] The nano-micro powder is added in the following manner: directly and evenly added to the surface of the medium bed, or mixed with the heavy oil wastewater to be treated and then added to the surface of the medium bed.

[0014] The present invention is further configured such that, in the medium bed layer, the hydrophilic and oleophobic particles and the oleophilic and hydrophobic particles have a particle size of 0.5 to 1.0 mm.

[0015] The present invention is further configured such that, in the composite particles of the medium bed layer, the oleophilic and hydrophobic particles and the hydrophilic and oleophobic particles are (1-3):1.

[0016] The present invention is further configured such that the porosity of the medium particles in the medium bed is 35-55%.

[0017] The present invention is further configured such that, in the composite particles, the difference in wetting contact angles between the oleophilic and hydrophobic particles and the hydrophilic and oleophobic particles in water is not less than 90°.

[0018] The present invention is further configured such that the bed medium filling volume of the microchannel separator accounts for 50% to 60% of its total volume.

[0019] The present invention is further configured such that the separation process also includes a backwash regeneration process for the medium bed, wherein the backwash regeneration process uses high-temperature gas to backwash and regenerate the medium bed. After cyclone separation, the backwash gas carries the nano-micro powder out of the microchannel separator and is separated by gas-solid cyclone to recover the nano-micro powder.

[0020] The present invention is further configured such that, in the backwash regeneration process, the bed space velocity of the microchannel separator is 10~15m / h, the ratio of the mass flow rate of the high-temperature gas used for backwash regeneration to the mass flow rate of the wastewater treated by the microchannel separator is 0.25%-0.5%; and the backwash time for each time is 20~45min.

[0021] The present invention further provides that the oil concentration in the heavy oil wastewater to be treated is 20-50000 mg / L. The oil concentration in the heavy oil wastewater = the mass of heavy oil in the heavy oil wastewater / the total volume of the heavy oil wastewater.

[0022] The present invention also provides a heavy oil wastewater separation device for implementing the above-mentioned separation process, comprising a microchannel separator and a medium bed layer arranged in the microchannel separator, wherein the surface layer of the medium bed layer is evenly doped with nano-micro powder, and the top and bottom of the microchannel separator are respectively provided with a wastewater inlet and a clean water outlet.

[0023] The present invention is further configured such that the separation device also includes a cyclone regeneration module, the cyclone regeneration module including a cyclone regenerator arranged at the top inside the microchannel separator and a gas-solid cyclone arranged outside the microchannel separator, a backwash outlet being provided on the top of the side wall of the cyclone regenerator, a cyclone backwash inlet being provided on the top of the cyclone regenerator, and a bottom flow outlet being provided at the bottom; a backwash material inlet being provided on the top side wall of the gas-solid cyclone, an overflow port and a solid discharge port being provided at the top and bottom ends respectively, the backwash outlet pipe of the cyclone regenerator being connected to the backwash material inlet of the gas-solid cyclone; and a backwash gas inlet being provided at the bottom of the microchannel separator.

[0024] The present invention is further configured such that the cyclone regenerator is a cyclone regenerator with a tangential inlet.

[0025] The present invention is further configured such that the separation pressure drop and the backwash pressure drop of the microchannel separator are both ≤0.05 MPa.

[0026] Compared with the prior art, the present invention has the following beneficial effects: (1) The separation device and separation process provided by the present invention are achieved by adding nanopowder to the surface of the medium particles in the microchannel separator and regulating the addition amount, particle size and type of the nanopowder, thereby significantly improving the oil removal effect of the microchannel medium layer, and the nanopowder can be recycled and reused.

[0027] (2) The separation device and separation process provided by the present invention do not require the addition of chemical agents, thereby reducing production costs; and the device and separation process are simple in structure, easy to implement, and convenient for promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Schematic diagram of the structure of the separation device described in an embodiment of the present invention; wherein, 100, microchannel separator, 110, medium bed, 120, wastewater inlet, 130, clean water outlet, 140, backwash gas inlet; 200, cyclone regenerator, 210, backwash inlet, 220, backwash outlet, 230, underflow port; 300, gas-solid cyclone, 310, backwash material inlet, 320, overflow port, 330, discharge port.

[0029] Figure 2 Schematic diagram of the experimental device for the microscopic process of oil droplet microchannel separation; including: 1. high-speed camera, 2. heterogeneous particles, 3. water tank, 4. syringe, 5. oil droplet.

[0030] Figure 3 The deformation process and movement path of the oil droplet after collision, (a) without nanopowder, (b) with nanopowder attached to the surface of the medium particles. DETAILED DESCRIPTION

[0031] The present invention is further described below by way of examples. The following examples are only used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0032] An embodiment of the present invention provides a heavy oil wastewater separation process regulated by nano-micro powder, wherein a microchannel separator provided with a medium bed is used to separate heavy oil wastewater, wherein the medium particles in the medium bed are composite particles composed of oleophilic and hydrophobic particles and hydrophilic and oleophobic particles, and nano-micro powder is uniformly added to the surface of the medium bed, wherein the nano-micro powder is hydrophobic particles with a particle size of 0.1 to 50 μm, and the nano-micro powder is selected from one or more of PP, PS, PE or PVC, and the ratio of the total mass of the added micro powder to the total mass of heavy oil in the heavy oil wastewater to be treated is 1:(1 to 200); the heavy oil wastewater to be treated enters the microchannel separator, first contacts with the nano-micro powder, and then is treated by the medium bed to obtain purified water after deoiling.

[0033] In the present invention, the oil concentration in the heavy oil wastewater to be treated is 20-50000 mg / L.

[0034] In one embodiment of the present invention, the particle size of the nanopowder is 0.5-20 μm.

[0035] In one embodiment of the present invention, the particle size of the nanopowder is 1.0-20 μm, for example, 1.0-5 μm, 5-10 μm, 10-15 μm or 15-20 μm.

[0036] In one embodiment of the present invention, the ratio of the mass of the added micro powder to the total mass of heavy oil in the heavy oil wastewater is 1:(1-20); preferably 1:(1-10).

[0037] In one embodiment of the present invention, the ratio of the mass of the added micropowder to the total mass of heavy oil in the heavy oil wastewater is 1:(1-5), for example, 1:1, 1:2, 1:3, 1:4 or 1:5.

[0038] In one embodiment of the present invention, in the medium bed layer, the hydrophilic and oleophobic particles and the oleophilic and hydrophobic particles have a particle size of 0.5-1.0 mm.

[0039] In one embodiment of the present invention, in the composite particles of the medium bed, the ratio of the oleophilic and hydrophobic particles to the hydrophilic and oleophobic particles is (1-3):1.

[0040] In one embodiment of the present invention, the porosity of the media particles in the media bed is 35-55%.

[0041] In one embodiment of the present invention, in the composite particles, the difference in wetting contact angles between the oleophilic-hydrophobic particles and the hydrophilic-oleophobic particles in water is not less than 90°.

[0042] In one embodiment of the present invention, the bed medium filling volume of the microchannel separator accounts for 50% to 60% of its total volume.

[0043] In one embodiment of the present invention, the separation process also includes a backwash regeneration process for the medium bed, wherein the backwash regeneration process uses high-temperature gas to backwash and regenerate the medium bed. After cyclone separation, the backwash gas carries the nano-micro powder out of the microchannel separator and is separated by gas-solid cyclone to recover the nano-micro powder.

[0044] In one embodiment of the present invention, in the backwash regeneration process, the bed space velocity of the microchannel separator is 10~15m / h, the ratio of the mass flow rate of the high-temperature gas used for backwash regeneration to the mass flow rate of the wastewater treated by the microchannel separator is 0.25%-0.5%; and the backwash time for each time is 20~45min.

[0045] The present invention also provides a heavy oil wastewater separation device for implementing the above separation process, such as Figure 1 As shown, it includes a microchannel separator 100 and a medium bed 110 provided in the microchannel separator 100, the surface of the medium bed is uniformly doped with nano-powder, and the top and bottom of the microchannel separator 100 are respectively provided with a wastewater inlet 120 and a clean water outlet 130; the microchannel separation device also includes a cyclone regeneration module, the cyclone regeneration module includes a cyclone regenerator 200 provided at the top of the microchannel separator 100 and a gas-solid cyclone 300 provided outside the microchannel separator 100, the cyclone regeneration module includes a cyclone regenerator 200 provided at the top of the microchannel separator 100 and a gas-solid cyclone 300 provided outside the microchannel separator 100, the cyclone regeneration module includes a cyclone regenerator 200 provided at the top of the microchannel separator 100 and a gas-solid cyclone 300 provided outside the microchannel separator 100, the gas-solid cyclone 300 provided at the top of ... A backwash outlet 220 is provided on the top of the side wall of the regenerator 200, a cyclone backwash inlet 210 is provided on the top of the cyclone regenerator 200, and an underflow port 230 is provided at the bottom; a backwash material inlet 310 is provided on the top side wall of the gas-solid cyclone 300, and an overflow port 320 and a discharge port 330 are provided at the top and bottom respectively, and the backwash outlet 220 pipe of the cyclone regenerator 200 is connected to the backwash material inlet 310 of the gas-solid cyclone 300; a backwash gas inlet 140 is also provided at the bottom of the microchannel separator 100.

[0046] In one embodiment of the present invention, the cyclone regenerator 200 is a cyclone regenerator with a tangential inlet.

[0047] In the technical solution of the present invention, the separation pressure drop and backwash pressure drop of the microchannel separator are both ≤0.05 MPa, so that the microchannel reactor can operate normally.

[0048] The technical solution of the present invention will be described in detail below with reference to specific embodiments. The heavy oil wastewater in the following embodiments is wastewater containing wax oil with a viscosity of 1-23 mPa.s discharged from a certain 800,000 tons / year polypropylene plant.

[0049] Example 1

[0050] In this embodiment, a heavy oil wastewater separation process regulated by nano-powder material is adopted. Figure 1 The heavy oil wastewater separation device shown treats heavy oil wastewater, which is heavy oil wastewater containing wax oil, and the wax oil concentration in the heavy oil wastewater is 1000 mg / L.

[0051] The microchannel separator 100 has an 80 mm diameter and contains a 50 cm high media bed 110. The media bed consists of an oleophilic anthracite medium and an oleophobic quartz sand medium in a 1:1 volume ratio. The media particles range in size from 0.5 to 1.0 mm, and the bed porosity is 45.2%. Nanopowder (PE nanopowder with a particle size of 50 μm) is evenly applied to the surface of the media bed. The ratio of the total mass of the nanopowder to the total mass of the heavy oil in the heavy oil wastewater to be treated is 1:10.

[0052] The workflow for treating heavy oil wastewater using the above-mentioned separation device is as follows: the heavy oil wastewater to be treated enters the microchannel separator 100 through the wastewater inlet 120. After coming into contact with the nanopowder on the surface of the media bed 110 of the microchannel separator 100, the wastewater flows through the media bed 110 and is discharged through the clean water outlet 130 at the bottom of the microchannel separator, resulting in purified water after oil removal. After the microchannel separator stabilized, the oil concentration in the purified water discharged from the clean water outlet 130 was measured to be 13.6 mg / L, and the residual PE powder in the purified water was also measured to be 2.02 mg / L, meeting the requirements for purified water.

[0053] After the microchannel separator has been running for 24 hours, the medium bed is backwashed and regenerated. The process is as follows: high-temperature gas is used to enter from the backwash gas inlet 140 at the bottom of the microchannel separator to backwash and regenerate the medium bed. The gas phase entrains heavy oil, nano-micro powder and trace medium particles on the top layer and enters the cyclone regenerator 200 upward. After separation in the cyclone regenerator, the medium particles return to the microchannel separator from the bottom flow port 230 of the cyclone regenerator. The high-temperature gas entrains heavy oil and nano-micro powder and is discharged through the backwash outlet 220. It continues to enter the gas-solid cyclone 300 through the backwash material inlet 310. After separation in the gas-solid cyclone, the nano-micro powder is discharged from the discharge port 330 at the bottom and recovered, and the gas phase is discharged through the overflow port 320 at the top.

[0054] During the backwash regeneration process, the bed space velocity of the microchannel separator was 15 m / h, the backwash regeneration time was 25 min, and the ratio of the mass flow rate of the high-temperature gas used for backwash regeneration to the mass flow rate of the wastewater treated in the microchannel separator was 0.35%. The exhaust gas discharged from the overflow port of the gas-solid cyclone was tested, and the concentration of nano-micro powder entrained in the exhaust gas was 6 mg / m 3 .

[0055] Example 2

[0056] Compared to Example 1, the only difference was the amount of nanopowder added. In this example, the ratio of the total mass of the nanopowder added to the total mass of the heavy oil in the heavy oil wastewater to be treated was 1:100, with all other conditions remaining the same. After the microchannel separator stabilized, the oil concentration in the purified water discharged from the clean water outlet was measured to be 18.7 mg / L.

[0057] After the microchannel separator was operated for 24 hours, the medium bed was backwashed and regenerated in the same manner as in Example 1. The exhaust gas discharged from the overflow port of the gas-solid cyclone was detected, and the concentration of nano-micro powder entrained in the exhaust gas was 5.8 mg / m 3 .

[0058] Example 3

[0059] Compared with Example 1, the only difference was the amount of nanopowder added. In this example, the ratio of the total mass of the added nanopowder to the total mass of the heavy oil in the heavy oil wastewater to be treated was 1:2. All other factors remained the same. The oil concentration in the purified water discharged from the purified water outlet was detected to be 5.45 mg / L.

[0060] After the microchannel separator was operated for 24 hours, the medium bed was backwashed and regenerated in the same manner as in Example 1. The exhaust gas discharged from the overflow port of the gas-solid cyclone was detected, and the concentration of nano-micro powder entrained in the exhaust gas was 7.5 mg / m 3 .

[0061] Example 4

[0062] Compared to Example 1, the only difference was the amount of nanopowder added. In this example, the ratio of the total mass of the nanopowder added to the total mass of heavy oil in the heavy oil wastewater to be treated was 1:200, with all other conditions remaining the same. The oil concentration in the purified water discharged from the water purification outlet was measured to be 98.7 mg / L. The purified water was also tested for residual PE powder. In this example, no PE powder was detected in the purified water.

[0063] After the microchannel separator was operated for 24 hours, the medium bed was backwashed and regenerated in the same manner as in Example 1. The exhaust gas discharged from the overflow port of the gas-solid cyclone was detected, and the concentration of nano-micro powder entrained in the exhaust gas was 3.2 mg / m 3 .

[0064] Example 5

[0065] Compared to Example 1, the only difference lies in the particle size of the nanopowder. In this example, PE nanopowder with a particle size of 15 μm was used, with all other conditions remaining the same. The oil concentration in the purified water discharged from the purified water outlet was measured to be 8.1 mg / L, while the residual PE powder in the purified water was measured to be 1.98 mg / L.

[0066] After the microchannel separator was operated for 24 hours, the medium bed was backwashed and regenerated in the same manner as in Example 1. The exhaust gas discharged from the overflow port of the gas-solid cyclone was detected, and the concentration of nano-micro powder entrained in the exhaust gas was 7.2 mg / m 3 .

[0067] Example 6

[0068] Compared to Example 1, the only difference is the particle size of the nanopowder. In this example, the nanopowder used was PE nanopowder with a particle size of 5 μm, with all other conditions remaining the same. The oil concentration in the purified water discharged from the purified water outlet was measured to be 6.3 mg / L, and the residual PE powder in the purified water was measured to be 1.06 mg / L.

[0069] After the microchannel separator was operated for 24 hours, the medium bed was backwashed and regenerated in the same manner as in Example 1. The exhaust gas discharged from the overflow port of the gas-solid cyclone was detected, and the concentration of nano-micro powder entrained in the exhaust gas was 5.7 mg / m 3 .

[0070] Example 7

[0071] Compared with Example 1, the only difference is the particle size of the nanopowder. In this example, the nanopowder used was PE nanopowder with a particle size of 150 μm, and all other conditions were the same. The oil concentration in the purified water discharged from the purified water outlet was 46.3 mg / L, and the residual PE powder in the purified water was 4.68 mg / L.

[0072] After the microchannel separator was operated for 24 hours, the medium bed was backwashed and regenerated in the same manner as in Example 1. The exhaust gas discharged from the overflow port of the gas-solid cyclone was detected, and the concentration of nano-micro powder entrained in the exhaust gas was 7.8 mg / m 3 .

[0073] Example 8

[0074] Compared with Example 1, the only difference is that the nanopowder material uses PS nanopowder with a particle size of 50 μm, and all other aspects are the same. The oil concentration in the purified water discharged from the purified water outlet is detected to be 8.3 mg / L.

[0075] After the microchannel separator was operated for 24 hours, the medium bed was backwashed and regenerated in the same manner as in Example 1. The concentration of nanopowder entrained in the exhaust gas discharged from the overflow port of the gas-solid cyclone was detected to be 7.1 mg / m 3 .

[0076] Example 9

[0077] Compared with Example 1, the only difference is that the nano-micro powder material is PVC nano-micro powder material with a particle size of 50 μm, and the other aspects are the same. The oil concentration in the purified water discharged from the purified water outlet is detected to be 5.2 mg / L.

[0078] After the microchannel separator was operated for 24 hours, the medium bed was backwashed and regenerated in the same manner as in Example 1. The concentration of nanopowder entrained in the exhaust gas discharged from the overflow port of the gas-solid cyclone was detected to be 6.83 mg / m 3 .

[0079] Example 10

[0080] Compared with Example 1, the only difference is that the nanopowder material uses PP nanopowder with a particle size of 50 μm, and all other aspects are the same. The oil concentration in the purified water discharged from the purified water outlet is detected to be 18.4 mg / L.

[0081] After the microchannel separator was operated for 24 hours, the medium bed was backwashed and regenerated in the same manner as in Example 1. The concentration of nanopowder entrained in the exhaust gas discharged from the overflow port of the gas-solid cyclone was detected to be 6.9 mg / m 3 .

[0082] Example 11

[0083] Compared with Example 1, the difference is that the media particles in the media bed layer only use oleophilic medium anthracite, and all other aspects are the same. The oil concentration in the purified water discharged from the purified water outlet is detected to be 35.4 mg / L.

[0084] After the microchannel separator was operated for 24 hours, the medium bed was backwashed and regenerated in the same manner as in Example 1. The concentration of nanopowder entrained in the exhaust gas discharged from the overflow port of the gas-solid cyclone was detected to be 13.5 mg / m 3 .

[0085] However, when only oleophilic media is used, the microchannel separator is easily clogged after running for a period of time. Therefore, it is preferred to use a combination of the hydrophilic and oleophobic particles and the oleophilic and hydrophobic particles.

[0086] Example 12

[0087] Compared with Example 1, the only difference is the amount of high-temperature gas inlet during the backwash regeneration process. In this embodiment, the ratio of the mass flow rate of the high-temperature gas used for backwash regeneration to the mass flow rate of the wastewater treated by the microchannel separator is 0.15%.

[0088] After the microchannel separator was operated for 24 hours, the medium bed was backwashed and regenerated in the same manner as in Example 1. The concentration of nanopowder entrained in the exhaust gas discharged from the overflow port of the gas-solid cyclone was detected to be 46.4 mg / m3 .

[0089] Example 13

[0090] Compared with Example 1, the only difference is the amount of high-temperature gas inlet during the backwash regeneration process. In this embodiment, the ratio of the mass flow rate of the high-temperature gas used for backwash regeneration to the mass flow rate of the wastewater treated by the microchannel separator is 0.6%.

[0091] After the microchannel separator was operated for 24 hours, the medium bed was backwashed and regenerated in the same manner as in Example 1. The concentration of nanopowder entrained in the exhaust gas discharged from the overflow port of the gas-solid cyclone was detected to be 12 mg / m 3 .

[0092] Example 14

[0093] Compared with Example 1, the difference is that the median particle size of the selected nanopowder is 17.6 μm, the wastewater to be treated is heavy oil wastewater discharged from a polypropylene device with a heavy oil concentration of 46756.8 mg / L, and the other conditions are the same.

[0094] After the microchannel separator was running stably, the oil concentration in the purified water discharged from the clean water outlet was detected to be reduced to 6.38 mg / L, and the residual PE powder in the purified water was detected to be 3.02 mg / L. After the microchannel separator was running for 24 hours, the medium bed was backwashed and regenerated in the same manner as in Example 1. The concentration of nano-micro powder entrained in the exhaust gas discharged from the overflow port of the gas-solid cyclone was detected to be 10.6 mg / m 3 .

[0095] Comparative Example 1

[0096] Compared with Example 1, the only difference is that no nano-micro powder is added to the microchannel separator. After testing, the oil concentration in the purified water discharged from the purified water outlet is 126.3 mg / L.

[0097] Comparative Example 2

[0098] Compared with Example 1, the only difference is that the medium particles in the medium bed layer are only oleophobic medium quartz sand, and all other aspects are the same. The oil concentration in the purified water discharged from the purified water outlet is detected to be 142.6 mg / L.

[0099] After 24 hours of operation, the medium bed was backwashed and regenerated, and the waste discharged from the overflow port of the gas-solid cyclone was detected. The concentration of the entrained nano-micro powder was 13.2 mg / m 3 .

[0100] Comparative Example 3

[0101] Compared with Example 1, the only difference is that the nanopowder material uses hydrophilic AC nanopowder with a particle size of 50 μm, and all other conditions are the same. The oil concentration in the purified water discharged from the purified water outlet is detected to be 235 mg / L.

[0102] After 24 hours of operation, the medium bed was backwashed and regenerated, and the waste discharged from the overflow port of the gas-solid cyclone was detected. The concentration of the entrained nano-micro powder was 8.8 mg / m 3 .

[0103] Mechanism analysis

[0104] like Figure 2 As shown, a two-dimensional, dual-component, synchronized high-speed camera system was used to observe the oil droplet collision process. The system consists of a droplet generation system and a high-speed camera system. The droplet generation system includes a microsyringe pump, a water tank 3, and heterogeneous particles 2 composed of an oleophilic medium, anthracite, and an oleophobic medium, quartz sand. The high-speed camera system primarily consists of two high-speed cameras 1. Oil was pushed from a syringe 4 at a rate of 2 mL / min through an oil pipeline to a fixed droplet generation needle. The water tank contained pure water to simulate the movement and migration of the oil phase in the aqueous system. The buoyancy of the oil droplet 5 overcame its surface tension and rose from the needle. The position of the medium particle was manually adjusted to ensure that the oil droplet collided with it. The experiment was captured from both the front and side using two high-speed cameras.

[0105] The heterogeneous particles were selected as the research object. The oil droplet was selected as white oil, and it collided head-on with the contact interface of fixed quartz sand-anthracite composite particles. The powder was 150μm PP powder. The powder was dispersed under the surface of the medium particles through high-speed camera process. The deformation process and movement path of the oil droplet after collision were as follows. Figure 3 As shown:

[0106] In the absence of nanopowder, after the oil droplet collides with the heterogeneous particle, it will first deform and then escape upward and finally be adhered to the particle; it takes 26 ms from the start of contact to the maximum deformation. The first oil droplet is adhered to the top of the particle due to buoyancy. After that, the second oil droplet will undergo a collision behavior similar to the first oil droplet, first colliding with the particle, then deforming and merging with the first oil droplet, the merging time taking 17 ms, and finally desorption due to the surface tension of the oil droplet, the desorption time taking 248 ms.

[0107] When the nanopowder and oil droplets are brought into contact and then collide with the medium particles, the nanopowder first covers the surface of the particles, that is, when MOA (oil-microplastic aggregates) are formed on the surface of the medium particles, the oil droplets will be quickly adsorbed by the powder to form a liquid bridge without colliding with the particles and deforming. It only takes 2 ms from contact to adhesion, which almost skips the spreading process of the oil droplets on the medium surface. The existence of MOA greatly enhances the medium particles' ability to capture oil droplets; after the oil droplets are captured by MOA, they diffuse on the medium surface, and the powder is absorbed inside the oil droplets, forming a powder-in-oil form; then, due to the strong adhesion effect of the powder, the oil droplets are stably fixed under the particles. Due to their lower kinetic energy, the subsequent oil droplets can neither break through the liquid film nor knock away the fixed previous droplets, and thus no coalescence occurs.

[0108] Therefore, according to the above content, it can be seen that the technical solution of the present invention covers the surface of the medium particles with powder, thereby affecting the law of microchannel medium particles capturing oil droplets. The powder adheres to the surface of the oil droplets, increasing the spreading time of the oil droplets on the medium, indirectly increasing the adhesion of the medium particles to the oil droplets, thereby significantly promoting the separation of the oil.

[0109] In summary, the technical solution of the present invention adopts a microchannel separator. By adding micro-nano powder to the surface of the microchannel medium bed and regulating the type, particle size and addition amount of the micro-nano powder, the oil removal effect of heavy oil wastewater is significantly improved, and unexpected excellent results are achieved; the process operation is simple and easy to promote and apply.

[0110] The above embodiments are intended only to illustrate the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made in accordance with the spirit of the present invention are intended to be covered by the scope of protection of the present invention.

Claims

1. A process for separating heavy oil wastewater using nanopowder-controlled separation, wherein the process uses a microchannel separator equipped with a medium bed to separate heavy oil wastewater, characterized in that: The medium particles in the medium bed are composite particles consisting of oleophilic and hydrophobic particles and hydrophilic and oleophobic particles. Nanopowder is uniformly added to the surface of the medium bed. The nanopowder is hydrophobic particles with a particle size of 0.1 to 50 μm. The nanopowder is selected from one or more of PP, PS, PE or PVC. The ratio of the total mass of the added nanopowder to the total mass of heavy oil in the heavy oil wastewater to be treated is 1:(1 to 200). The heavy oil wastewater to be treated enters the microchannel separator and contacts the nanopowder, and then is treated by the medium bed to obtain purified water after deoiling.

2. The process for separating heavy oil wastewater using nanopowder according to claim 1, characterized in that: The particle size of the nanopowder is 1.0-20 μm.

3. The process for separating heavy oil wastewater using nanopowder according to claim 1, characterized in that: The ratio of the added nano-micro powder to the total mass of heavy oil in the heavy oil wastewater to be treated is 1: (1-20).

4. The process for separating heavy oil wastewater using nanopowder control according to claim 1, characterized in that: In the medium bed, the hydrophilic and oleophobic particles and the oleophilic and hydrophobic particles have a particle size of 0.5 to 1.0 mm.

5. The process for separating heavy oil wastewater using nanopowder control according to claim 4, characterized in that: The ratio of the oleophilic to hydrophobic particles to the hydrophilic to oleophobic particles in the media particles is (1-3):1; the bed media filling volume of the microchannel separator accounts for 50%-60% of its total volume, and the porosity of the media particles in the media bed is 35-55%.

6. The process for separating heavy oil wastewater using nanopowder according to claim 1, characterized in that: The method also includes a backwash regeneration process for the medium bed, wherein the backwash regeneration process uses high-temperature gas to backwash and regenerate the medium bed. After cyclone separation, the backwash gas carries the nano-micro powder out of the microchannel separator and is separated by gas-solid cyclone to recover the nano-micro powder.

7. The process for separating heavy oil wastewater using nanopowder control according to claim 6, characterized in that: In the backwash regeneration process, the bed space velocity of the microchannel separator is 10-15 m / h, and the ratio of the mass flow rate of the high-temperature gas used for backwash regeneration to the mass flow rate of the wastewater treated by the microchannel separator is 0.25%-0.5%.

8. The process for separating heavy oil wastewater using nanopowder control according to claim 1, wherein: The oil concentration in the heavy oil wastewater to be treated is 20~50000 mg / L.

9. A heavy oil wastewater separation device for implementing the separation process according to any one of claims 1 to 8, characterized in that: The invention comprises a microchannel separator and a medium bed layer arranged in the microchannel separator. The surface layer of the medium bed layer is uniformly doped with nano-micro powder. The top and bottom of the microchannel separator are respectively provided with a wastewater inlet and a clean water outlet.

10. The heavy oil wastewater separation device according to claim 9, characterized in that: The separation device also includes a cyclone regeneration module, which includes a cyclone regenerator located at the top of the microchannel separator and a gas-solid cyclone located outside the microchannel separator. A backwash outlet is provided on the top of the side wall of the cyclone regenerator, a cyclone backwash inlet is provided on the top of the cyclone regenerator, and an underflow port is provided at the bottom; a backwash material inlet is provided on the top side wall of the gas-solid cyclone, and an overflow port and a solid discharge port are provided at the top and bottom respectively; the backwash outlet pipe of the cyclone regenerator is connected to the backwash material inlet of the gas-solid cyclone; and a backwash gas inlet is provided at the bottom of the microchannel separator.

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