Efficient oil and gas field produced water efficient regulation, storage and oil removal device and use method thereof

Abstract

The invention relates to the technical field of oil field produced water purification treatment, in particular to an efficient oil field produced water efficient storage adjusting and oil removing device and a using method thereof.The efficient oil field produced water efficient storage adjusting and oil removing device comprises a purification treatment unit, a storage adjusting and oil removing unit and a backflow gas dissolving unit, the purification treatment unit comprises an upper tower body, and the storage adjusting and oil removing unit comprises a middle tower body and a lower tower body; the backflow gas dissolving unit comprises a backflow gas dissolving pump, oily sewage is subjected to primary purification treatment through the dissolved gas release flotation degreaser, then is subjected to secondary purification treatment through the gathering degreaser and then is settled, purified water is subjected to homogeneous and average adjustment and then is discharged, and part of homogeneous and average purified water is returned to serve as gas dissolving water. The device is simple, convenient to operate, low in energy consumption and low in investment, the purification treatment unit and the regulation, storage and oil removal unit are arranged in the device in a segmented mode, the treatment time is shortened, the treatment efficiency of the device is improved, the water quality treatment effect is improved, and the device can be widely applied to oil field conventional water drive and steam drive produced water treatment and gas field produced water treatment.

Description

Technical Field

[0001] The invention relates to the technical field of oilfield produced water purification and treatment, and is a highly efficient oilfield produced water high-efficiency storage and oil removal device and a use method thereof. Background Art

[0002] In the domestic oil and gas field produced water treatment process, a storage and oil removal unit must be set up at the front end. The main functions of this treatment unit are two-fold: one is to adjust and balance the water volume; the other is primary purification treatment to ensure that the water quality entering the subsequent treatment unit is within the design allowable index range.

[0003] At present, the storage tanks of domestic oilfield produced water treatment stations mainly adopt natural sedimentation separation or coagulation sedimentation separation technology. The storage tanks usually adopt vertical vault tanks. The tanks are divided into water distribution area, sedimentation separation area, water collection area, sludge area, oil collection area, etc. according to functional areas. The tanks are equipped with water distribution devices, sludge discharge devices and oil collection devices. After treatment, the removal rate of suspended solids is about 50%, and the removal rate of oil is between 60% and 80%.

[0004] Due to the functions of regulating and balancing water volume and primary sewage purification, the oil-removing tank is an indispensable treatment unit in the design of produced water treatment process, which can effectively ensure the stability of water inflow and water quality of subsequent treatment units of produced water. However, the produced water storage and oil-removing tanks currently used in domestic oil fields have the following problems: 1) The equipment is large and can only be manufactured and installed on site: At present, most of the domestic oil and gas field produced water treatment storage and oil removal tank process design adopts natural sedimentation separation technology, which relies on the density difference of oil, water and slag to achieve gravity separation. For produced water with relatively high floating oil content, the removal rate is relatively high, but for produced water with high dispersed oil and emulsified oil content and high mineralization, its treatment efficiency is low and the effect is poor. The effective residence time of sewage in conventional water drive produced water storage tank is 3h to 4h, 4h to 8h for heavy oil, and 8h to 12h for super heavy oil, resulting in low liquid level load of storage tank, large equipment volume and large size, which can only be manufactured on site, requiring a lot of manpower, long construction period and large land area.

[0005] 2) Low treatment efficiency and large fluctuations in treated water quality: The oil-removal tank adopts natural sedimentation separation technology, which can only remove floating oil, dispersed oil and solid impurities with larger particle size within the effective residence time, and cannot effectively remove emulsified oil and suspended solids with small particle size and light specific gravity. Especially when the amount and quality of water for crude oil treatment fluctuate, the water quality of the effluent fluctuates greatly, which in turn affects the effect of the next-level produced water treatment unit.

[0006] 3) Cannot meet the requirements of skid-mounted design, factory prefabrication, and unitized assembly: With the development of the national economy and the advancement of technology in various industries, the development and construction model of oil and gas fields is also constantly developing and improving, gradually shifting from the traditional low-efficiency, high-cost intensive on-site construction model to a construction model that pursues high efficiency, low cost, skid-mounted design, factory prefabrication, and on-site unit assembly. At present, the oil storage and de-oiling tanks used in oilfield produced water treatment can no longer meet the needs of modern engineering construction.

[0007] In order to solve the above problems, it is urgent to develop a new type of produced water storage and oil removal equipment with high efficiency, improve the equipment processing efficiency and load, reduce the equipment volume and size, realize the equipment's small skid-mounted design, factory prefabrication, and on-site unit assembly, thereby improving the overall economic benefits of the project construction. Summary of the invention

[0008] The present invention provides an efficient oil and gas field produced water high-efficiency storage and oil removal device and a method of using the same, which overcomes the deficiencies of the above-mentioned prior art and can effectively solve the problems of large equipment size, low treatment efficiency, large fluctuations in treated water quality and high treatment cost in the existing oil and gas field produced water treatment.

[0009] One of the technical solutions of the present invention is achieved through the following measures: an efficient oil and gas field produced water high-efficiency storage and oil removal device, including a purification treatment unit, a storage and oil removal unit and a reflux dissolved gas unit, the lower part of the purification treatment unit is fixedly connected with the storage and oil removal unit, a U-shaped liquid phase communication pipeline is fixedly connected between the first liquid outlet on the upper part of the purification treatment unit and the lower liquid inlet of the storage and oil removal unit, a gas phase communication pipeline is fixedly connected between the upper air inlet of the purification treatment unit and the upper air outlet of the storage and oil removal unit, and the upper first liquid inlet of the purification treatment unit is fixedly connected with the production The outlet liquid pipeline, the second liquid inlet at the bottom of the purification treatment unit is fixedly connected to the external tower service water pipeline, the second liquid outlet at the top of the purification treatment unit is fixedly connected to the dirty oil discharge pipeline, the third liquid inlet in the middle of the purification treatment unit and the liquid outlet of the reflux dissolved gas unit are fixedly connected with the dissolved gas reflux outlet pipeline, the lower liquid outlet of the purification treatment unit is fixedly connected with the sludge discharge pipeline, the lower liquid outlet of the regulating, storage and oil removal unit and the liquid inlet of the reflux dissolved gas unit are fixedly connected with the dissolved gas reflux inlet pipeline, and the bottom liquid outlet of the regulating, storage and oil removal unit is fixedly connected with the purified water discharge pipeline.

[0010] The following is a further optimization and / or improvement of one of the above-mentioned technical solutions: The above-mentioned purification treatment unit includes an upper tower body, which is fixedly connected with the regulating, storing and oil-removing unit. A U-shaped liquid phase communication pipeline is fixedly connected between the first liquid outlet on the upper tower body and the lower liquid inlet of the regulating, storing and oil-removing unit, and a gas phase communication pipeline is fixedly connected between the upper air inlet of the upper tower body and the upper air outlet of the regulating, storing and oil-removing unit. An oil collecting tank, a liquid equalizing distributor, a dissolved air release flotation deoiler and an agglomeration deoiler are fixedly arranged in the upper tower body from top to bottom. The bottom outlet of the oil collecting tank is fixedly connected with a dirty oil discharge pipeline, the inlet of the liquid equalizing distributor is fixedly connected with a produced water inlet pipeline, the inlet of the dissolved air release flotation deoiler and the liquid outlet of the reflux dissolved air unit are fixedly connected with a dissolved air reflux water outlet pipeline, a high-pressure washer is arranged between the bottom and the top of the agglomeration deoiler, and the bottom outlet of the upper tower body is fixedly connected with a sludge discharge pipeline.

[0011] The above-mentioned regulating, storing and oil-removing unit includes a middle tower body and a lower tower body. The top of the middle tower body is fixedly connected with the bottom of the upper tower body, and a gas-phase communicating pipeline is fixedly connected between the upper air outlet of the middle tower body and the upper air inlet of the upper tower body. The lower tower body includes a uniform liquid regulating storage tank and a base. The bottom of the middle tower body is fixedly connected with the top of the uniform liquid regulating storage tank, and a U-shaped liquid-phase communicating pipeline is fixedly connected between the upper liquid inlet of the uniform liquid regulating storage tank and the first upper liquid outlet of the upper tower body. A dissolved gas reflux water inlet pipeline is fixedly connected between the lower liquid outlet of the base and the liquid inlet of the reflux dissolved gas unit, and a purified water discharge pipeline is fixedly connected to the liquid outlet at the bottom of the base.

[0012] The above-mentioned reflux dissolved air unit includes a reflux dissolved air pump, a dissolved air reflux water inlet pipeline is fixedly connected between the liquid inlet of the reflux dissolved air pump and the liquid outlet at the bottom of the equalizing liquid regulating storage tank, and a dissolved air reflux water outlet pipeline is fixedly connected between the liquid outlet of the reflux dissolved air pump and the inlet of the dissolved air release flotation deoiler.

[0013] The dissolved air reflux outlet pipeline is fixedly installed with a first water inlet flowmeter, the gas reflux inlet pipeline between the first water inlet flowmeter and the reflux dissolved air pump is fixedly connected with an air intake pipeline, and the air intake flowmeter is fixedly installed on the air intake pipeline.

[0014] A second water inlet flowmeter is fixedly installed on the above-mentioned produced water inlet pipeline, a gas-liquid stabilizer is fixedly installed on the dissolved gas reflux outlet pipeline, a purified water outlet regulating valve is fixedly installed on the purified water discharge pipeline, a first liquid level transmitter is arranged on the uniform liquid regulating storage tank, a second liquid level transmitter is arranged on the upper tower body, and an interlock is arranged between the purified water outlet regulating valve and the first liquid level transmitter.

[0015] The reflux air dissolving pump is a variable frequency pump, and an interlock is arranged between the reflux air dissolving pump and the first water inlet flow meter.

[0016] The top and bottom of the high-pressure washer are both provided with flushing outlets, and flushing nozzles are fixedly installed on the flushing outlets. The agglomeration degreaser is filled with a high specific surface area agglomeration filler.

[0017] The above-mentioned storage and oil removal unit and reflux dissolved gas unit are both skid-mounted units.

[0018] The second technical solution of the present invention is achieved through the following measures: a method for using an efficient oil and gas field produced water high-efficiency storage and oil removal device, which is carried out according to the following steps: in the first step, the oily wastewater is measured by the second water inlet flowmeter and then sent to the equalizing liquid distributor on the upper part of the upper tower body by the produced water inlet pipeline; in the second step, the oily wastewater flows from top to bottom after being evenly distributed by the equalizing liquid distributor, and is purified once by a dissolved air release flotation deoiler to obtain primary purified water, wherein the dissolved air water forms dense microbubbles through the dissolved air release flotation deoiler, and part of the dirty oil and suspended matter in the oily wastewater adheres to the microbubbles, quickly floats to the top of the upper tower body with the microbubbles, accumulates, and is discharged from the dirty oil discharge pipeline after being collected in the oil collecting tank; in the third step, the primary purified water continues to flow from top to bottom, and is purified twice by the agglomeration deoiler to obtain secondary purified water, wherein the primary purified water and the agglomeration deoiler are The high specific surface area coalescing filler in the deoiler contacts and collides repeatedly, and the smaller oil droplets in the primary purified water coalesce and grow to form large oil droplets, which also float up rapidly with the microbubbles, accumulate at the top of the upper tower body, and are discharged from the waste oil discharge pipeline after being collected in the oil collecting tank; in the fourth step, the secondary purified water is settled at the lower part of the upper tower body, and the heavy particle impurities with a large specific gravity sink to the bottom of the upper tower body and are discharged through the sludge discharge pipeline. The purified water after settling is sent to the uniform liquid adjustment storage tank through the U-shaped liquid phase connecting pipeline for homogenization and uniform quantity adjustment to obtain homogenous and uniform quantity purified water; in the fifth step, the homogenous and uniform quantity purified water is discharged from the bottom of the lower tower body through the purified water discharge pipeline, wherein air or inert gas enters through the suction pipeline, is mixed with part of the homogenous and uniform quantity purified water in the dissolved air reflux inlet pipeline, and is sent to the reflux dissolved air pump, and after being pressurized and dissolved by the reflux dissolved air pump, is sent to the dissolved air release flotation deoiler as dissolved air water through the dissolved air reflux outlet pipeline.

[0019] The equipment of the present invention is simple, easy to operate, has low energy consumption and low investment, and purification treatment units and storage and oil removal units are arranged in sections in the equipment, which reduces the treatment time, improves the equipment treatment efficiency, and improves the water quality treatment effect. The equipment can be widely used in conventional water drive and steam drive produced water treatment in oil fields and produced water treatment in gas fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Attached Figure 1 This is a process flow chart of Example 1 of the present invention.

[0021] The codes in the attached drawings are: 1 is the upper tower body, 2 is the middle tower body, 3 is the lower tower body, 4 is the U-shaped liquid phase connecting pipeline 4, 5 is the gas phase connecting pipeline, 6 is the produced water inlet pipeline, 7 is the service water pipeline outside the tower, 8 is the dirty oil discharge pipeline, 9 is the dissolved gas reflux outlet pipeline, 10 is the sludge discharge pipeline, 11 is the dissolved gas reflux inlet pipeline, 12 is the purified water discharge pipeline, 13 is the oil collecting tank, 14 is the liquid distributor, 15 is Dissolved air release flotation deoiler, 16 is an aggregation deoiler, 17 is a high-pressure washer, 18 is a uniform liquid adjustment storage tank, 19 is a reflux dissolved air pump, 20 is a first water inlet flow meter, 21 is an air suction line, 22 is an air inlet flow meter, 23 is a second water inlet flow meter, 24 is a gas-liquid stabilizer, 25 is a purified water outlet regulating valve, 26 is a first liquid level transmitter, 27 is a second liquid level transmitter, 28 is a flushing nozzle, and 29 is a base. DETAILED DESCRIPTION

[0022] The present invention is not limited by the following embodiments, and specific implementation methods can be determined based on the technical solution of the present invention and actual conditions.

[0023] The present invention will be further described below in conjunction with embodiments: Embodiment 1: As attached Figure 1 As shown, the efficient oil and gas field produced water high-efficiency storage and oil removal device comprises a purification treatment unit, a storage and oil removal unit and a reflux dissolved gas unit. The lower part of the purification treatment unit is fixedly connected with the storage and oil removal unit. A U-shaped liquid phase communication pipeline 4 is fixedly connected between the first liquid outlet at the top of the purification treatment unit and the lower liquid inlet of the storage and oil removal unit. A gas phase communication pipeline 5 is fixedly connected between the upper air inlet of the purification treatment unit and the upper air outlet of the storage and oil removal unit. The first liquid inlet at the top of the purification treatment unit is fixedly connected with a produced water liquid pipeline 6. The purification treatment unit The second lower liquid inlet is fixedly connected to an external tower service water pipeline 7, the second upper liquid outlet of the purification treatment unit is fixedly connected to a dirty oil discharge pipeline 8, the third liquid inlet in the middle of the purification treatment unit and the liquid outlet of the reflux dissolved gas unit are fixedly connected to a dissolved gas reflux water outlet pipeline 9, the lower liquid outlet of the purification treatment unit is fixedly connected to a sludge discharge pipeline 10, the lower liquid outlet of the regulating and storage oil removal unit and the liquid inlet of the reflux dissolved gas unit are fixedly connected to a dissolved gas reflux water inlet pipeline 11, and the bottom liquid outlet of the regulating and storage oil removal unit is fixedly connected to a purified water discharge pipeline 12.

[0024] The highly efficient oil and gas field produced water storage and oil removal device of the present invention provides a tower-structured oil field produced water treatment device, and through the combined design of a purification treatment unit, a storage and oil removal unit and a reflux dissolved gas unit, the equipment treatment efficiency is increased by 2 to 3 times compared with the traditional large tank sedimentation equipment, and the water quality treatment effect is improved. The present invention can be widely used in conventional water drive and steam drive oil field produced water treatment at home and abroad, as a primary purification treatment and water volume regulation unit for oil field produced water. It is suitable for water with an oil content of ≤1000mg / L and suspended matter of ≤300mg / L. After the treatment of the present invention, the oil removal rate reaches 80%, and the suspended matter removal rate is 50% to 60%, ensuring that the oil content of the outlet water is ≤150mg / L and the suspended matter is ≤150mg / L, providing homogeneous and uniform water for the lower stage process of produced water treatment.

[0025] Embodiment 2: As an optimization of the above embodiment, as shown in the attached Figure 1 As shown, the purification treatment unit includes an upper tower body 1, which is fixedly connected to the regulating, storing and oil-removing unit. A U-shaped liquid phase communication pipeline 4 is fixedly connected between the first liquid outlet on the upper tower body 1 and the lower liquid inlet of the regulating, storing and oil-removing unit, and a gas phase communication pipeline 5 is fixedly connected between the upper air inlet of the upper tower body 1 and the upper air outlet of the regulating, storing and oil-removing unit. An oil collecting tank 13, a liquid equalizing distributor 14, a dissolved gas release flotation deoiler 15, and an aggregation deoiler 16 are fixedly arranged in the upper tower body 1 from top to bottom. The bottom outlet of the oil collecting tank 13 is fixedly connected to a dirty oil discharge pipeline 8, the inlet of the liquid equalizing distributor 14 is fixedly connected to a produced water liquid pipeline 6, the inlet of the dissolved gas release flotation deoiler 15 and the liquid outlet of the reflux dissolved gas unit are fixedly connected to a dissolved gas reflux water outlet pipeline 9, a high-pressure washer 17 is arranged between the bottom and the top of the aggregation deoiler 16, and the bottom outlet of the upper tower body 1 is fixedly connected to a sludge discharge pipeline 10.

[0026] The liquid equalizing distributor 14 in the present invention can be a circular cylindrical structure, adopting a herringbone type water distribution pattern, and the size of the distributor and the arrangement of the herringbone water spray pipes are determined according to the treatment volume of the oily wastewater.

[0027] The dissolved air release flotation deoiler 15 and the agglomeration deoiler 16 are arranged in the purification treatment unit, which significantly improves the treatment efficiency of the equipment. In particular, the dissolved air release flotation deoiler 15 can use a special aeration releaser, and the bubble diameter can be controlled to be dense microbubbles of 30µm to 40µm, and the air flotation contact time can be controlled to be 5min to 10min according to the oil content in the water and the particle size of the oil droplets.

[0028] According to the needs, the dissolved air release flotation deoiler 15 and the agglomeration deoiler 16 in the present invention are arranged at different height sections in the tower, and the setting position can be determined after calculation according to the treatment volume and water quality conditions. The treated water flows from top to bottom, and first flows through the dissolved air release flotation deoiler 15 for primary purification treatment, and then flows through the agglomeration deoiler 16 for secondary purification treatment after stabilization.

[0029] Embodiment 3: As an optimization of the above embodiment, as shown in the attached Figure 1 As shown, the regulating, storing and oil-removing unit includes a middle tower body 2 and a lower tower body 3, the top of the middle tower body 2 is fixedly connected with the bottom of the upper tower body 1, and a gas-phase communicating pipeline 5 is fixedly connected between the upper gas outlet of the middle tower body 2 and the upper gas inlet of the upper tower body 1, the lower tower body 3 includes a uniform liquid regulating storage tank 18 and a base 29, the bottom of the middle tower body 2 is fixedly connected with the top of the uniform liquid regulating storage tank 18, a U-shaped liquid-phase communicating pipeline 4 is fixedly connected between the upper liquid inlet of the uniform liquid regulating storage tank 18 and the first upper liquid outlet of the upper tower body 1, a dissolved gas reflux water inlet pipeline 11 is fixedly connected between the lower liquid outlet of the base 29 and the liquid inlet of the reflux dissolved gas unit, and a purified water discharge pipeline 12 is fixedly connected to the bottom liquid outlet of the base 29.

[0030] According to needs, the U-shaped liquid phase communicating pipeline 4 in the present invention extends into the lower part of the upper tower body 1, so that the purified water after sedimentation is discharged from the bottom of the upper tower body 1 through the U-shaped liquid phase communicating pipeline 4 to the tower bottom equalizing storage tank. This design can avoid the formation of siphon suction.

[0031] Embodiment 4: As an optimization of the above embodiment, as shown in the attached Figure 1 As shown, the reflux dissolved air unit includes a reflux dissolved air pump 19, a dissolved air reflux water inlet pipeline 11 is fixedly connected between the liquid inlet of the reflux dissolved air pump 19 and the liquid outlet at the bottom of the equalizing liquid storage tank 18, and a dissolved air reflux water outlet pipeline 9 is fixedly connected between the liquid outlet of the reflux dissolved air pump 19 and the inlet of the dissolved air release flotation deoiler 15.

[0032] According to needs, the reflux air dissolving pump 19 in the present invention adopts a multiphase flow air dissolving pump, and a power system is formed by pressurizing the reflux liquid. The solubility of the liquid when the gas is dissolved can reach 100% saturation, and the average diameter of the bubble is ≤30 microns. The gas is directly sucked into the inlet of the reflux air dissolving pump 19. Compared with the traditional flotation system, it is easy to realize the suction of homogeneous and uniform purified water from the uniform liquid adjustment tank 18, and it can save air compressors, pressure vessels, releasers, control systems and valves, centrifugal pumps and other equipment, saving production costs.

[0033] Embodiment 5: As an optimization of the above embodiment, as shown in the attached Figure 1 As shown, a first water inlet flowmeter 20 is fixedly installed on the dissolved air reflux outlet pipeline 9, an air intake pipeline 21 is fixedly connected to the air reflux inlet pipeline between the first water inlet flowmeter 20 and the reflux dissolved air pump 19, and an air intake flowmeter 22 is fixedly installed on the air intake pipeline 21.

[0034] According to the requirements, the installation height of the air suction pipeline 21 in the present invention should be higher than the installation height of the liquid-balancing storage tank 18 .

[0035] Embodiment 6: As an optimization of the above embodiment, as shown in the attached Figure 1As shown, a second water inlet flowmeter 23 is fixedly installed on the produced water inlet pipeline 6, a gas-liquid stabilizer 24 is fixedly installed on the dissolved gas reflux outlet pipeline 9, a purified water outlet regulating valve 25 is fixedly installed on the purified water discharge pipeline 12, a first liquid level transmitter 26 is arranged on the average liquid regulating storage tank 18, a second liquid level transmitter 27 is arranged on the upper tower body 1, and an interlock is arranged between the purified water outlet regulating valve 25 and the first liquid level transmitter 26.

[0036] According to the needs, in the present invention, a gas-liquid stabilizer 24 is provided before the homogeneous and uniform purified water as dissolved gas water (i.e., pressurized dissolved gas reflux liquid) enters the purification treatment unit to ensure sufficient dissolution and mixing of the gas phase and the liquid phase.

[0037] The uniform liquid regulating storage tank 18 in the present invention has the function of regulating the uneven incoming liquid. Through the interlock between the first liquid level transmitter 26 and the purified water outlet regulating valve 25 and the interlock between the first liquid level transmitter 26 and the lifting pump of the downstream process, it is convenient to ensure that uniform and uniform water is provided to the downstream process.

[0038] Embodiment 7: As an optimization of the above embodiment, as shown in the attached Figure 1 As shown, the reflux air dissolving pump 19 is a variable frequency pump, and an interlock is provided between the reflux air dissolving pump 19 and the first water inlet flow meter 20 .

[0039] According to the needs, the interlock between the reflux air dissolving pump 19 and the first water inlet flowmeter 20 in the present invention facilitates the timely monitoring of the changes in the reflux water volume, the air intake volume, and the incoming liquid volume and the stable control of the device operation.

[0040] Embodiment 8: As an optimization of the above embodiment, as shown in the attached Figure 1 As shown, the top and bottom of the high-pressure washer 17 are provided with flushing outlets, and a flushing nozzle 28 is fixedly installed on the flushing outlet. The agglomeration degreaser 16 is filled with a high specific surface area agglomeration filler.

[0041] As needed, the high-pressure washer 17 in the present invention is connected to the service water outside the tower through the service water pipeline 7 outside the tower, and the flushing nozzles 28 are evenly distributed above and below the aggregation oil remover 16, so as to facilitate the irregular cleaning of the aggregation oil remover 16 by high-pressure water to avoid the clogging of the gaps in the aggregation packing due to impurities.

[0042] In the present invention, the agglomeration oil remover 16 is regularly filled with a high specific surface area agglomeration filler, and the specific surface area of ​​the high specific surface area agglomeration filler can be selected according to the impurity content in the water. 2 / m 3 Up to 400m 2 / m 3 、Liquid level load 25m 3 / m 2 .h to 30m 3 / m 2.h, packing volume load 20m 3 / m 3 、Liquid level load 25m 3 / m 2 .h to 28m 3 / m 2 .h. The high specific surface area agglomeration filler has the characteristics of large surface area, high agglomeration load, good anti-fouling and plugging performance, short agglomeration reaction and separation time, which greatly improves the separation and treatment effect of oily wastewater.

[0043] Embodiment 9: As an optimization of the above embodiment, as shown in the attached Figure 1 As shown, the storage and oil removal unit and the reflux dissolved gas unit are both skid-mounted units.

[0044] According to the needs, the storage and oil removal unit and the reflux dissolved gas unit in the present invention are both skid-mounted units, which reduce the volume and size of the equipment, facilitate factory prefabrication and modular construction, reduce the floor space, shorten the construction period, and reduce the production cost investment.

[0045] In the present invention, unless otherwise specified, the equipment and devices used are all the equipment and devices known and used in the art.

[0046] Embodiment 10: The method for using the highly efficient oil and gas field produced water storage and oil removal device is carried out according to the following steps: First, the oily wastewater is measured by the second water inlet flowmeter 23 and then sent to the liquid distributor 14 at the upper part of the upper tower body 1 through the produced water inlet pipeline 6; Second, the oily wastewater flows from top to bottom after being evenly distributed by the liquid distributor 14, and is purified once by the dissolved air release flotation deoiler 15 to obtain a purified water, wherein the dissolved air water is formed into a dense Microbubbles, part of the dirty oil and suspended matter in the oily wastewater (depending on gravity difference) adhere to the microbubbles, quickly float to the top of the upper tower body 1 with the microbubbles, accumulate, and are collected by the oil collecting tank 13 and discharged from the dirty oil discharge pipeline 8; In the third step, the primary purified water continues to flow from top to bottom, and is subjected to secondary purification treatment by the agglomeration degreasing device 16 to obtain secondary purified water, wherein the primary purified water repeatedly contacts and collides with the high specific surface area agglomeration filler in the agglomeration degreasing device 16, and the smaller oil droplets in the primary purified water agglomerate and increase to form The large oil droplets (due to gravity difference) also float up quickly with the microbubbles, accumulate at the top of the upper tower body 1, and are collected in the oil collecting tank 13 and discharged from the waste oil discharge pipeline 8; in the fourth step, the secondary purified water is settled at the lower part of the upper tower body 1, and the heavy particulate impurities with a large specific gravity (due to gravity difference) sink to the bottom of the upper tower body 1 and are discharged through the sludge discharge pipeline 10. The purified water after settling is sent to the equalizing liquid adjustment storage tank 18 through the U-shaped liquid phase communication pipeline 4 for homogenization and equalization to obtain homogenized and equalized purified water; in the fifth step, the homogenized and equalized purified water is purified Water is discharged from the bottom of the lower tower body 3 through the purified water discharge pipeline 12, wherein air or inert gas (whose flow rate can be 5% to 15% of the homogeneous and average purified water flow rate in the dissolved air reflux water inlet pipeline 11) enters through the air suction pipeline 21, and is mixed with part of the homogeneous and average purified water (which can be 20% to 30% of the oily wastewater treatment volume) in the dissolved air reflux water inlet pipeline 11 and then sent to the reflux dissolved air pump 19. After being pressurized and dissolved by the reflux dissolved air pump 19, it is sent to the dissolved air release flotation deoiler 15 through the dissolved air reflux water outlet pipeline 9 as dissolved air water.

[0047] In the present invention, the working process of the reflux dissolved air unit is mainly to extract a certain proportion of homogeneous and uniform purified water from the uniform liquid storage tank 18, pressurize it through the reflux dissolved air pump 19, and inhale a certain amount of air or inert gas to form a high-pressure multiphase flow dissolved air water, which is sent to the dissolved air release flotation oil remover 15 of the purification treatment unit to complete the air flotation oil removal, and then realize the operation of the reflux water volume, air intake volume, and liquid volume change stabilization device through data collection, monitoring and interlocking control.

[0048] Embodiment 11: Oil treatment system removes oily wastewater (oil content 955mg / L, suspended solids 253mg / L, pressure 0.25MPa) and enters the upper purification treatment unit of the high-efficiency oil and gas field produced water high-efficiency storage and oil removal device by self-pressure. After being evenly distributed by the liquid distributor 14, it flows at a uniform speed from top to bottom in the device, and passes through the dissolved gas release flotation deoiler 15 and the aggregation deoiler 16 in sequence. The dirty oil and suspended solids in the water are reduced, and the floating oil and suspended solids with low specific gravity naturally float to the top oil collecting tank 13 of the tower under the action of bubbles by gravity difference, and the heavy particle impurities with high specific gravity sink to the bottom of the upper tower body 1. The purified water is introduced from the bottom of the upper tower body 1 through the U-shaped liquid phase communication pipeline 4 into the liquid equalization storage tank 18 at the bottom of the lower tower body 3. After homogenization and equalization, the homogenized and equalized purified water (oil content 50mg / L, suspended solids 35mg / L) enters the downstream process.

[0049] As needed, the pipelines and equipment of the efficient oil and gas field produced water efficient storage and oil removal device can also be equipped with conventional valves, thermometers and pressure gauges known in the art according to production needs.

[0050] In summary, the equipment of the present invention is simple, easy to operate, has low energy consumption and low investment, and the purification treatment unit and the storage and oil removal unit are arranged in sections in the equipment, which reduces the processing time, improves the equipment processing efficiency, and improves the water quality treatment effect. It can be widely used in conventional water drive and steam drive produced water treatment in oil fields and produced water treatment in gas fields.

[0051] The above technical features constitute the embodiments of the present invention, which have strong adaptability and implementation effect. Non-essential technical features can be added or reduced according to actual needs to meet the requirements of different situations.

Claims

1. An efficient oil and gas field produced water efficient storage and oil removal device, characterized in that The invention comprises a purification treatment unit, a storage and oil removal unit and a reflux dissolved gas unit. The lower part of the purification treatment unit is fixedly connected with the storage and oil removal unit. A U-shaped liquid phase communication pipeline is fixedly connected between the first liquid outlet at the top of the purification treatment unit and the lower liquid inlet of the storage and oil removal unit. A gas phase communication pipeline is fixedly connected between the upper air inlet of the purification treatment unit and the upper air outlet of the storage and oil removal unit. The first liquid inlet at the top of the purification treatment unit is fixedly connected with a produced water liquid pipeline. The second liquid inlet at the bottom of the purification treatment unit is fixedly connected with a The second liquid outlet on the upper part of the purification treatment unit is fixedly connected with a dirty oil discharge pipeline, the third liquid inlet in the middle of the purification treatment unit and the liquid outlet of the reflux dissolved gas unit are fixedly connected with a dissolved gas reflux water outlet pipeline, the lower liquid outlet of the purification treatment unit is fixedly connected with a sludge discharge pipeline, the lower liquid outlet of the regulating, storage and oil removal unit and the liquid inlet of the reflux dissolved gas unit are fixedly connected with a dissolved gas reflux water inlet pipeline, and the bottom liquid outlet of the regulating, storage and oil removal unit is fixedly connected with a purified water discharge pipeline.

2. The highly efficient oil and gas field produced water storage and oil removal device according to claim 1 is characterized in that The purification treatment unit includes an upper tower body, which is fixedly connected with the regulating, storing and oil removing unit. A U-shaped liquid phase communication pipeline is fixedly connected between the first liquid outlet on the upper tower body and the lower liquid inlet of the regulating, storing and oil removing unit. A gas phase communication pipeline is fixedly connected between the upper air inlet of the upper tower body and the upper air outlet of the regulating, storing and oil removing unit. An oil collecting tank, a liquid equalizing distributor, a dissolved air release flotation deoiler and an agglomeration deoiler are fixedly arranged in the upper tower body from top to bottom. The bottom outlet of the oil collecting tank is fixedly connected with a dirty oil discharge pipeline, the inlet of the liquid equalizing distributor is fixedly connected with a produced water liquid pipeline, the inlet of the dissolved air release flotation deoiler and the liquid outlet of the reflux dissolved air unit are fixedly connected with a dissolved air reflux water outlet pipeline, a high-pressure washer is arranged between the bottom and the top of the agglomeration deoiler, and the bottom outlet of the upper tower body is fixedly connected with a sludge discharge pipeline.

3. The efficient oil and gas field produced water efficient storage and oil removal device according to claim 2 is characterized in that The regulating, storing and oil removing unit comprises a middle tower body and a lower tower body, the top of the middle tower body is fixedly connected with the bottom of the upper tower body, the upper air outlet of the middle tower body and the upper air inlet of the upper tower body are fixedly connected with a gas phase communicating pipeline, the lower tower body comprises a uniform liquid regulating storage tank and a base, the bottom of the middle tower body is fixedly connected with the top of the uniform liquid regulating storage tank, the upper liquid inlet of the uniform liquid regulating storage tank and the first upper liquid outlet of the upper tower body are fixedly connected with a U-shaped liquid phase communicating pipeline, the lower liquid outlet of the base and the liquid inlet of the reflux dissolved gas unit are fixedly connected with a dissolved gas reflux water inlet pipeline, and the bottom liquid outlet of the base is fixedly connected with a purified water discharge pipeline.

4. The efficient oil and gas field produced water efficient storage and oil removal device according to claim 3 is characterized in that The reflux dissolved air unit comprises a reflux dissolved air pump, a dissolved air reflux water inlet pipeline is fixedly connected between the liquid inlet of the reflux dissolved air pump and the liquid outlet at the bottom of the equalizing liquid regulating storage tank, and a dissolved air reflux water outlet pipeline is fixedly connected between the liquid outlet of the reflux dissolved air pump and the inlet of the dissolved air release flotation deoiler.

5. The efficient oil and gas field produced water efficient storage and oil removal device according to claim 4 is characterized in that A first water inlet flowmeter is fixedly installed on the dissolved air reflux outlet pipeline, an air intake pipeline is fixedly connected to the air reflux inlet pipeline between the first water inlet flowmeter and the reflux dissolved air pump, and an air intake flowmeter is fixedly installed on the air intake pipeline.

6. The highly efficient oil and gas field produced water storage and oil removal device according to any one of claims 1 to 5, characterized in that A second water inlet flowmeter is fixedly installed on the produced water inlet pipeline, a gas-liquid stabilizer is fixedly installed on the dissolved gas reflux outlet pipeline, a purified water outlet regulating valve is fixedly installed on the purified water discharge pipeline, a first liquid level transmitter is arranged on the uniform liquid regulating storage tank, a second liquid level transmitter is arranged on the upper tower body, and an interlock is arranged between the purified water outlet regulating valve and the first liquid level transmitter.

7. The efficient oil and gas field produced water efficient storage and oil removal device according to claim 5 or 6, characterized in that The reflux dissolved air pump is a variable frequency pump, and an interlock is arranged between the reflux dissolved air pump and the first water inlet flow meter.

8. The highly efficient oil and gas field produced water storage and oil removal device according to any one of claims 2 to 7, characterized in that Flushing outlets are arranged at the top and the bottom of the high-pressure washer, and flushing nozzles are fixedly installed on the flushing outlets. The agglomeration degreaser is filled with a high specific surface area agglomeration filler.

9. The highly efficient oil and gas field produced water storage and oil removal device according to any one of claims 2 to 8, characterized in that The storage and oil removal unit and the reflux dissolved gas unit are both skid-mounted units.

10. A method for using the highly efficient oil and gas field produced water storage and oil removal device according to any one of claims 1 to 5, characterized in that The following steps are followed: in the first step, the oily wastewater is measured by the second water inlet flowmeter and then sent to the equalizing liquid distributor on the upper part of the upper tower body through the produced water inlet pipeline; in the second step, the oily wastewater is evenly distributed by the equalizing liquid distributor and flows from top to bottom, and is purified once by the dissolved air release flotation deoiler to obtain primary purified water, wherein the dissolved air water forms dense microbubbles through the dissolved air release flotation deoiler, and part of the dirty oil and suspended matter in the oily wastewater adheres to the microbubbles, quickly floats to the top of the upper tower body with the microbubbles, accumulates, and is discharged from the dirty oil discharge pipeline after being collected in the oil collecting tank; in the third step, the primary purified water continues to flow from top to bottom, and is purified twice by the agglomeration deoiler to obtain secondary purified water, wherein the primary purified water repeatedly contacts and collides with the high specific surface area agglomeration filler in the agglomeration deoiler, and the primary purified water is The smaller oil droplets in the treated water coalesce and grow to form large oil droplets, which also float rapidly with the microbubbles, accumulate at the top of the upper tower body, and are discharged from the waste oil discharge pipeline after being collected in the oil collecting tank; in the fourth step, the secondary purified water is settled at the lower part of the upper tower body, and the heavy particle impurities with a large specific gravity sink to the bottom of the upper tower body and are discharged through the sludge discharge pipeline. The purified water after settlement is sent to the uniform liquid adjustment tank through the U-shaped liquid phase connecting pipeline for homogenization and equalization to obtain homogenous and equalized purified water; in the fifth step, the homogenous and equalized purified water is discharged from the bottom of the lower tower body through the purified water discharge pipeline, wherein air or inert gas enters through the suction pipeline, is mixed with part of the homogenized and equalized purified water in the dissolved air reflux inlet pipeline, and is sent to the reflux dissolved air pump, and after being pressurized and dissolved by the reflux dissolved air pump, is sent to the dissolved air release flotation deoiler as dissolved air water through the dissolved air reflux outlet pipeline.

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