Pretreatment system for high-salinity fracturing flow-back fluid

Abstract

The utility model discloses a high-salinity fracturing flow-back fluid pretreatment system which comprises an electro-oxidation reactor, an electric flocculation reactor, an inclined plate sedimentation tank and a fiber turntable filter tank which are arranged in sequence, and a water outlet of the electro-oxidation reactor is communicated with a water inlet of the electric flocculation reactor; a water inlet of the inclined plate sedimentation tank is communicated with a water outlet of the electric flocculation reactor, and a water inlet of the fiber turntable filter tank is communicated with a water outlet of the inclined plate sedimentation tank. A combination form of an electrooxidation reactor, an electric flocculation reactor, an inclined plate sedimentation tank and a fiber turntable filter tank is adopted to pretreat the high-salinity fracturing flow-back fluid, so that the high-salinity fracturing flow-back fluid can be ensured to stably reach the standard in the pretreatment process of the high-salinity fracturing flow-back fluid.

Description

Technical Field

[0001] The utility model relates to the technical field of high-mineralization fracturing flowback fluid pretreatment, in particular to a high-mineralization fracturing flowback fluid pretreatment system. Background Art

[0002] Membrane treatment is generally used in the deep treatment of oil and gas field fracturing flowback fluids. The membrane treatment method has relatively high requirements for the quality of the influent water. When using the membrane treatment method to treat fracturing flowback fluids, in addition to controlling the suspended solids in the influent water, it is also necessary to oxidize and remove the colloidal substances in the water. If they cannot be effectively removed, the risk of membrane blockage will increase. Therefore, effective pretreatment of the wastewater is necessary before it enters the membrane treatment system. Electrochemical treatment devices have received widespread attention in the field of oilfield wastewater environmental protection. Medium filtration is a commonly used technology for removing suspended solids in the field of oilfield environmental protection. However, for wastewater with a high degree of mineralization, structural hardening is prone to occur, which affects production. In view of this, in-depth research on the above issues has led to the creation of this case. Utility Model Content

[0003] In response to the shortcomings of the existing technology, the utility model provides a high-mineralization fracturing return fluid pretreatment system, which solves the problem in the existing technology that the fracturing return fluid wastewater with high mineralization is prone to surface hardening of the filter membrane structure during the membrane treatment process.

[0004] To achieve the above objectives, the present invention is implemented through the following technical solutions: a high-mineralization fracturing return fluid pretreatment system, comprising an electro-oxidation reactor, an electro-flocculation reactor, an inclined plate sedimentation tank and a fiber rotary disk filter arranged in sequence, the water outlet of the electro-oxidation reactor is connected to the water inlet of the electro-flocculation reactor, the water inlet of the inclined plate sedimentation tank is connected to the water outlet of the electro-flocculation reactor, and the water inlet of the fiber rotary disk filter is connected to the water outlet of the inclined plate sedimentation tank.

[0005] The bottoms of the electro-oxidation reactor and the electro-flocculation reactor are both provided with microporous aeration disks.

[0006] The electro-oxidation electrode arranged in the electro-oxidation reactor is a DSA electrode or a BDD electrode.

[0007] Aluminum or iron electrodes are arranged in the above-mentioned electric flocculation reactor.

[0008] A mud discharge pipe is provided at the lower part of the inclined plate sedimentation tank, and a backwash mechanism is provided at one side of the inclined plate sedimentation tank, with the outlet end of the backwash mechanism facing the lower part of the inclined plate in the inclined plate sedimentation tank.

[0009] A backwashing device is provided on one side of the fiber rotary filter, and one end of the backwashing device extends into the fiber rotary filter.

[0010] The utility model provides a high-mineralization fracturing flowback fluid pretreatment system. It has the following beneficial effects: the high-mineralization fracturing flowback fluid pretreatment system adopts a combination of an electro-oxidation reactor, an electro-flocculation reactor, an inclined plate sedimentation tank and a fiber rotary disc filter to pretreat the high-mineralization fracturing flowback fluid, so as to ensure that the high-mineralization fracturing flowback fluid pretreatment is stable and meets the standards; the electro-oxidation reactor mainly oxidizes organic matter, colloidal substances and the like in the fracturing flowback fluid, reduces the viscosity of the water, and reduces the processing load of the membrane treatment system; the electro-flocculation reactor mainly targets suspended matter or colloidal substances in the fracturing flowback fluid, and has a certain effect on removing boron ions in the fracturing fluid, effectively reducing the subsequent membrane treatment or ion exchange resin treatment load and improving the treatment efficiency; the suspended matter in the effluent of the inclined plate sedimentation tank is below 50 mg / L, and after further treatment in the fiber rotary disc filter, the suspended matter can reach 10 mg / L or below, meeting the water inlet requirements of membrane treatment or resin treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a schematic diagram of the main structure of a high-mineralization fracturing flowback fluid pretreatment system described in the present invention.

[0012] In the figure: 1. Electro-oxidation reactor; 2. Electro-flocculation reactor; 3. Inclined plate sedimentation tank; 4. Fiber rotary disc filter; 5. Microporous aeration plate; 6. Sludge discharge pipe; 7. Backwash mechanism; 8. Backwash device. DETAILED DESCRIPTION

[0013] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0014] Example: In conjunction with the specification Figure 1It can be seen that in order to solve the problem in the prior art that the surface of the filter membrane structure of the fracturing return fluid wastewater with high mineralization is prone to hardening during the membrane treatment process, the present application specifically designs a high-mineralization fracturing return fluid pretreatment system, comprising an electro-oxidation reactor 1, an electro-flocculation reactor 2, an inclined plate sedimentation tank 3 and a fiber rotary disk filter 4 arranged in sequence, the outlet of the electro-oxidation reactor 1 is connected to the water inlet of the electro-flocculation reactor 2, the water inlet of the inclined plate sedimentation tank 3 is connected to the water outlet of the electro-flocculation reactor 2, and the water inlet of the fiber rotary disk filter 4 is connected to the water outlet of the inclined plate sedimentation tank 3. The combination of the electro-oxidation reactor 1, the electro-flocculation reactor 2, the inclined plate sedimentation tank 3 and the fiber rotary disk filter 4 is used to pretreat the high-mineralization fracturing return fluid to ensure the high-mineralization fracturing The pretreatment of the return fluid is stable and meets the standards; the electro-oxidation reactor 1 is mainly used to oxidize organic matter, colloidal substances, etc. in the fracturing return fluid, reduce the viscosity of the water, and reduce the processing load of the membrane treatment system; the electro-flocculation reactor 2 is mainly used to remove suspended matter or colloidal substances in the fracturing return fluid, and at the same time has a certain effect on removing boron ions in the fracturing fluid, effectively reducing the subsequent membrane treatment or ion exchange resin treatment load and improving the treatment efficiency; the wastewater after electro-oxidation and electro-flocculation treatment enters the inclined plate sedimentation tank 3, and the large particle sediment is separated in the inclined plate sedimentation tank 3. The suspended matter in the effluent of the inclined plate sedimentation tank 3 is below 50 mg / L. After further treatment by the fiber rotary disc filter 4, the suspended matter can reach 10 mg / L or below, meeting the water inlet requirements of membrane treatment or resin treatment.

[0015] In the specific implementation process, as a preferred setting, the bottom of the above-mentioned electro-oxidation reactor 1 and the electro-flocculation reactor 2 are both provided with microporous aeration disks 5, and hydraulic mixing is performed using the microporous aeration disks 5; the hydraulic mixing gas-liquid ratio is 1:2 to 1:3.

[0016] In the specific implementation process, as a preferred setting, the electro-oxidation electrode provided in the electro-oxidation reactor 1 is a DSA electrode or a BDD electrode; and the electro-flocculation reactor 2 is provided with an aluminum or iron electrode.

[0017] During the specific implementation process, as a preferred setting, a mud discharge pipe 6 is provided at the lower part of the above-mentioned inclined plate sedimentation tank 3, and a backwashing mechanism 7 is provided on one side of the inclined plate sedimentation tank 3, and the outlet end of the backwashing mechanism 7 is facing the lower part of the inclined plate in the inclined plate sedimentation tank 3; a backwashing device 8 is provided on one side of the fiber rotary disk filter 4, and one end of the backwashing device 8 extends into the fiber rotary disk filter 4; the backwash intensity is 10 to 15 m³ / min; hydraulic backwashing, air backwashing or both can be used.

[0018] Among them, it is important to point out that the energy supply of the electro-oxidation reactor 1 and the electro-flocculation reactor 2 can be selected from traditional energy or on-site natural gas power generation or solar energy, especially for the treatment of fracturing return fluid in Inner Mongolia, where the solar energy resources are very rich, the equipment operation cost can be greatly reduced.

[0019] Although the embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A high-mineralization fracturing flowback fluid pretreatment system, characterized in that: The invention comprises an electro-oxidation reactor, an electro-flocculation reactor, an inclined plate sedimentation tank and a fiber rotary disk filter arranged in sequence, wherein the water outlet of the electro-oxidation reactor is connected with the water inlet of the electro-flocculation reactor, the water inlet of the inclined plate sedimentation tank is connected with the water outlet of the electro-flocculation reactor, and the water inlet of the fiber rotary disk filter is connected with the water outlet of the inclined plate sedimentation tank.

2. A high-mineralization fracturing flowback fluid pretreatment system according to claim 1, characterized in that: The bottoms of the electro-oxidation reactor and the electro-flocculation reactor are both provided with microporous aeration disks.

3. A high-mineralization fracturing flowback fluid pretreatment system according to claim 1, characterized in that: The electro-oxidation electrode arranged in the electro-oxidation reactor is a DSA electrode or a BDD electrode.

4. A high-mineralization fracturing flowback fluid pretreatment system according to claim 1, characterized in that: Aluminum or iron electrodes are arranged in the electric flocculation reactor.

5. The high-mineralization fracturing flowback fluid pretreatment system according to claim 1, characterized in that: A mud discharge pipe is provided at the lower part of the inclined plate sedimentation tank, and a backwash mechanism is provided at one side of the inclined plate sedimentation tank. The outlet end of the backwash mechanism is directly opposite to the lower part of the inclined plate in the inclined plate sedimentation tank.

6. A high-mineralization fracturing flowback fluid pretreatment system according to claim 1, characterized in that: A backwashing device is provided on one side of the fiber rotary filter, and one end of the backwashing device extends into the fiber rotary filter.

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