Air floatation combined treatment device for gas field produced water

Abstract

The utility model discloses an air floatation combined treatment device for gas field produced water, which comprises an adjusting tank and a first water pump connected to the rear end of the adjusting tank, and the tail end of the first water pump is respectively connected with a first-stage three-phase vortex air floatation and a second-stage multi-phase equilibrium air floatation. And the first-stage three-phase vortex air floatation comprises a water inlet valve I connected to the water outlet end of the first water pump. According to the device disclosed by the utility model, the water inlet valve I, the water inlet valve II and the branch water outlet valve I and the branch water outlet valve II of the water outlet pipe are arranged, so that the gas field produced water can be independently subjected to primary three-phase vortex air floatation treatment, secondary multi-phase balanced air floatation treatment and combined treatment of primary three-phase vortex air floatation and secondary multi-phase balanced air floatation; the three treatment modes are adopted to adapt to different requirements, the treatment efficiency of the gas field produced water is remarkably improved, oil drops and suspended solids in the produced water are more comprehensively removed, different treatment modes are selected according to needs, energy can be saved, the cost can be reduced, and the practicability of the device is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of gas field produced water treatment, in particular to an air flotation combined treatment device for gas field produced water. Background Art

[0002] A large amount of produced water is generated during the exploitation process of gas fields. The produced water contains crude oil, organic matter, acid and alkali, high concentration of salt, suspended matter and complex organic components. The water quality has the significant characteristics of "four highs and one low", such as high mineralization, high turbidity, high iron content, high corrosiveness and low pH value. These characteristics make the treatment of produced water difficult and costly. As an effective means of solid-liquid separation, flotation technology can effectively remove impurities such as oil droplets and suspended matter in produced water and improve water quality. The treatment of gas field produced water requires the selection of reasonable treatment processes and equipment according to the specific composition and characteristics of the produced water.

[0003] In this regard, a series of produced water treatment processes have been developed, generally including physical sedimentation, filtration, chemical reaction and other methods. However, it is often difficult to make the produced water standard by applying only this technology, so deep treatment methods are required. Generally, the deep treatment technology of produced water is mainly dissolved air flotation treatment technology. However, due to the addition of a large number of chemical agents, including foaming agents, corrosion inhibitors, scale inhibitors, etc., to gas wells in recent years, the water properties of gas field produced water have changed greatly. The foam-like substances in the sewage have increased significantly, showing emulsification and floating phenomena. In addition, since the wastewater comes from different gas wells and different production periods, the water quality is extremely unstable. The traditional single flotation process can no longer meet the needs of gas field water treatment with variable water quality. Therefore, a flotation combined treatment device for gas field produced water is proposed. The combined device significantly improves the treatment efficiency of gas field produced water, removes oil droplets and suspended solids in produced water more comprehensively, and can select different treatment processes according to the changes in on-site water quality, adapt to the characteristics of variable water quality and difficulty in treatment, save energy, reduce costs, and improve the practicality of the device. Utility Model Content

[0004] The utility model aims to solve one of the technical problems existing in the prior art or related technology.

[0005] To this end, the technical solution adopted in this utility model is:

[0006] A combined flotation treatment device for produced water from a gas field, comprising a regulating tank, a first water pump connected to the rear end of the regulating tank, the ends of the first water pump are respectively connected to a first-stage three-phase vortex flotation and a second-stage multiphase balanced flotation, the first-stage three-phase vortex flotation comprises a water inlet valve connected to the water outlet end of the first water pump, a three-phase vortex mixer arranged at the rear end of the water inlet valve, a dosing device and an exhaust device installed on the three-phase vortex mixer, a mud outlet trough connected to the side of the three-phase vortex mixer, and a bottom end fixed to the three-phase vortex mixer and the mud outlet trough. An outlet pipe, outlet valves 1 and 2 arranged on the outlet pipe, and an exhaust gas treatment device 1 installed on the top of the three-phase vortex mixer. The secondary multiphase balanced flotation includes a coagulation and flocculation tank connected to the rear end of the outlet valve 2, a dosing device 2 installed on the coagulation and flocculation tank, a stirrer arranged inside the coagulation and flocculation tank, a scraping device connected to the top of the rear end of the coagulation and flocculation tank, a mud outlet tank 2 arranged below the scraping device, a clear liquid storage tank installed at the end of the coagulation and flocculation tank, and an exhaust gas treatment device 2 arranged on the coagulation and flocculation tank.

[0007] Preferably, the water outlet end of the water inlet valve 1 is also connected to the water inlet valve 2, and the rear end of the water inlet valve 2 is connected to the water inlet end of the coagulation and flocculation tank.

[0008] Preferably, an equalizer is connected to the middle position of the bottom of the coagulation and flocculation tank, and the other end of the equalizer is connected to an air dissolving pump.

[0009] Preferably, the end of the water outlet valve 1 is connected to the clear liquid storage tank.

[0010] Preferably, the number of the dosing device 1 and the number of the dosing device 2 are both two, and the number of the mixers is also two corresponding to the number of the dosing device 2.

[0011] By adopting the above technical solution, the beneficial effects achieved by the utility model are as follows:

[0012] In the utility model, by arranging water inlet valve 1, water inlet valve 2 and two branch water outlet valves 1 and 2 of the water outlet pipe, the produced water of the gas field can be subjected to the first-stage three-phase vortex flotation treatment, the second-stage multiphase balanced flotation treatment and the combined treatment of the first-stage three-phase vortex flotation and the second-stage multiphase balanced flotation treatment, and the three treatment methods can be adapted to different needs.

[0013] The unique vortex three-phase mixer of the first-stage three-phase vortex flotation in this device can complete all the steps of high-pressure air dissolution, agent molecule stretching and efficiency improvement, coagulation and flocculation stirring (pollutant capture), floc formation, bubble nucleus generation and ultra-light hollow floc formation. The three-phase vortex flotation has a small gas production volume, which has great advantages for produced water with added foaming agent, and each three-phase vortex mixer is equipped with a dosing port and a sampling port, which can quickly compare the added agent and the effect. When the properties, temperature and flow rate of produced water change, the dosage of the agent can be changed or replaced in time, and the obtained effect can be identified and judged in real time to ensure stable treatment. The second-stage multiphase balanced flotation adopts a nitrogen-sealed micro-pressure system, whose bubbles are at the micro-nano level and have a large gas production volume. Smaller bubbles will increase the contact area between solid particles and it, thereby improving adhesion and greatly improving the ability to remove residual impurities in the front-end desulfurization process of produced water.

[0014] Therefore, in the actual treatment process, attention should be paid to the actual water quality of the source of produced water, and different treatment methods should be reasonably selected according to the specific conditions of the produced water. The combined process of phase vortex flotation + multiphase equilibrium flotation combines the technical advantages of two types of flotation, has good anti-fluctuation ability, and can well match the unstable water quality of gas field produced water. This combined process can be used as a priority for oil removal and SS removal in the pretreatment section of gas field produced water, which can save energy, reduce costs, and improve the practicality of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is an overall schematic diagram of an embodiment of the utility model;

[0016] Figure 2 The present invention is a flow chart of an embodiment of the present invention.

[0017] Reference numerals:

[0018] 1. Regulating tank; 2. First water pump;

[0019] 100. One-stage three-phase vortex flotation; 3. One water inlet valve; 4. One dosing device; 5. Three-phase vortex mixer; 6. Exhaust device; 7. Two water inlet valves; 8. One tail gas treatment device; 9. Water outlet pipe; 10. One mud outlet trough; 11. One water outlet valve; 12. Two water outlet valves;

[0020] 200. Secondary multiphase balanced flotation; 13. Coagulation and flocculation tank; 14. Dosing device 2; 15. Slag scraping device; 16. Mixer; 17. Mud discharge tank 2; 18. Clear liquid storage tank; 19. Equalizer; 20. Dissolved air pump; 21. Tail gas treatment device 2. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solution and advantages of the utility model clearer, the utility model is further described in detail below in combination with specific implementation methods and with reference to the accompanying drawings. It should be noted that the embodiments of the utility model and the features in the embodiments can be combined with each other without conflict.

[0022] A combined flotation treatment device for gas field produced water provided by some embodiments of the utility model will be described below in conjunction with the accompanying drawings.

[0023] Example:

[0024] Combination Figure 1-2 As shown, the utility model provides a gas field produced water flotation combined treatment device, comprising a regulating tank 1, a first water pump 2 connected to the rear end of the regulating tank 1, the ends of the first water pump 2 are respectively connected to a primary three-phase vortex flotation 100 and a secondary multiphase balanced flotation 200, the primary three-phase vortex flotation 100 comprises an inlet valve 3 connected to the water outlet end of the first water pump 2, a three-phase vortex mixer 5 arranged at the rear end of the inlet valve 3, a dosing device 4 and an exhaust device 6 installed on the three-phase vortex mixer 5, a mud outlet trough 10 connected to the side of the three-phase vortex mixer 5, an outlet pipe 9 fixed to the three-phase vortex mixer 5 and the bottom of the mud outlet trough 10, an outlet valve 11 and an outlet valve 2 12 arranged on the outlet pipe 9, and an exhaust gas treatment device 8 assembled on the top of the three-phase vortex mixer 5, and the secondary multiphase balanced flotation 200 comprises a water outlet valve 11 connected to the rear end of the outlet valve 12. The coagulation and flocculation tank 13, the dosing device 14 installed on the coagulation and flocculation tank 13, the stirrer 16 arranged inside the coagulation and flocculation tank 13, the scraper 15 connected to the top of the rear end of the coagulation and flocculation tank 13, the mud outlet tank 17 arranged below the scraper 15, the clear liquid storage tank 18 installed at the end of the coagulation and flocculation tank 13, the tail gas treatment device 21 arranged on the coagulation and flocculation tank 13, the water outlet end of the water inlet valve 13 is also connected to the water inlet valve 27, the rear end of the water inlet valve 27 is connected to the water inlet end of the coagulation and flocculation tank 13, the middle position of the bottom of the coagulation and flocculation tank 13 is connected to an equalizer 19, the other end of the equalizer 19 is connected to an air dissolving pump 20, the end of the water outlet valve 11 is connected to the clear liquid storage tank 18, the number of the dosing device 14 and the dosing device 2 14 are both two, and the number of the stirrer 16 is also two corresponding to the number of the dosing device 2 14.

[0025] Specifically, by setting a mud discharge trough 10 on one side of the three-phase vortex mixer 5, the scum in the three-phase vortex mixer 5 is gathered on the pool surface, piled up and bonded to form a scum blanket, which is scraped to the mud discharge trough 10 by a scraper plate and discharged to the outside. The first-stage three-phase vortex flotation 100 has a good treatment effect on floating objects and gas field produced water containing a large amount of foaming agent and emulsified oil;

[0026] By setting a scraper device 15 on the coagulation and flocculation tank 13, the floating objects are scraped into the mud outlet tank 17 and then discharged. The secondary multiphase balanced flotation 200 focuses on removing floating objects, sediments and large oil droplets due to its micro-nano bubbles and large gas production. The functional focus is different from that of the primary three-phase vortex flotation 100. The functions of the two complement each other. When it contains a large amount of foaming agent and emulsified oil, it can only be treated by the primary three-phase vortex flotation 100. When there are more floating objects and sediments, it can only be treated by the secondary multiphase balanced flotation 200. When there are more floating objects, sediments, and oil droplets and chemical reagents such as foaming agents are contained, the primary three-phase vortex flotation 100 and the secondary multiphase balanced flotation 200 can be operated jointly to deeply treat the produced water to ensure the quality of the treatment.

[0027] The working principle and use process of the utility model are as follows: first, the gas field produced water is received and processed through the regulating tank 1, and then pumped into the three-phase vortex mixer 5 through the first water pump 2. After being processed by the three-phase vortex mixer 5, the silt and the like in the produced water are discharged from the sludge outlet trough 10, and at the same time, the outlet valve 2 12 is opened to allow the produced water treated by the three-phase vortex mixer 5 to enter the coagulation and flocculation tank 13 for treatment, and the floating objects are scraped off by the scraping device 15. Finally, the produced water enters the clear liquid storage tank 18 for discharge to complete the treatment of the produced water. In addition, when there are no floating objects, the produced water treated by the three-phase vortex mixer 5 can be discharged into the clear liquid storage tank 18 by opening the outlet valve 11 and closing the outlet valve 2 12, or when there is no silt, the inlet valve 13 is closed and the inlet valve 2 7 is opened to directly extract the produced water inside the regulating tank 1 into the coagulation and flocculation tank 13 for treatment, and finally the device can be inspected and maintained regularly.

[0028] Although the embodiments of the present invention have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and purpose of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A combined flotation treatment device for gas field produced water, comprising a regulating tank (1), a first water pump (2) connected to the rear end of the regulating tank (1), characterized in that: The ends of the first water pump (2) are respectively connected to a first-stage three-phase vortex air flotation (100) and a second-stage multi-phase balanced air flotation (200); A first-stage three-phase vortex flotation (100) comprises a water inlet valve (3) connected to the water outlet end of a first water pump (2), a three-phase vortex mixer (5) arranged at the rear end of the water inlet valve (3), a dosing device (4) and an exhaust device (6) installed on the three-phase vortex mixer (5), a mud outlet trough (10) connected to the side of the three-phase vortex mixer (5), a water outlet pipe (9) fixed to the bottom of the three-phase vortex mixer (5) and the mud outlet trough (10), a water outlet valve (11) and a water outlet valve (12) arranged on the water outlet pipe (9), and an exhaust gas treatment device (8) mounted on the top of the three-phase vortex mixer (5); A two-stage multiphase balanced flotation (200) comprises a coagulation and flocculation tank (13) connected to the rear end of a second water outlet valve (12), a second dosing device (14) mounted on the coagulation and flocculation tank (13), a stirrer (16) arranged inside the coagulation and flocculation tank (13), a scraping device (15) connected to the top of the rear end of the coagulation and flocculation tank (13), a second mud outlet tank (17) arranged below the scraping device (15), a clear liquid storage tank (18) installed at the end position of the coagulation and flocculation tank (13), and a second tail gas treatment device (21) arranged on the coagulation and flocculation tank (13).

2. The combined flotation treatment device for gas field produced water according to claim 1, characterized in that: The water outlet end of the water inlet valve 1 (3) is also connected to the water inlet valve 2 (7), and the rear end of the water inlet valve 2 (7) is connected to the water inlet end of the coagulation and flocculation tank (13).

3. The combined flotation treatment device for gas field produced water according to claim 1, characterized in that: An equalizer (19) is connected to the middle position of the bottom of the coagulation and flocculation tank (13), and the other end of the equalizer (19) is connected to an air dissolving pump (20).

4. The combined flotation treatment device for gas field produced water according to claim 1, characterized in that: The end of the water outlet valve 1 (11) is connected to the clear liquid storage tank (18).

5. The combined flotation treatment device for gas field produced water according to claim 1, characterized in that: The number of the dosing device 1 (4) and the number of the dosing device 2 (14) are both two, and the number of the mixers (16) is also two corresponding to the number of the dosing device 2 (14).

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