CN215855385U

CN215855385U - Oil field produced liquid water purification device

Info

Publication number: CN215855385U
Application number: CN202022983828.7U
Authority: CN
Inventors: 赵毅; 徐梦瑶; 钟荣强; 赵德银; 郭靖; 陈红举; 任广欣; 杨思远; 崔伟; 滕建强
Original assignee: China Petroleum and Chemical Corp; Sinopec Northwest Oil Field Co
Current assignee: China Petroleum and Chemical Corp; Sinopec Northwest Oil Field Co
Priority date: 2020-12-11
Filing date: 2020-12-11
Publication date: 2022-02-18
Anticipated expiration: 2030-12-11

Abstract

The utility model provides a water quality purification device for oilfield produced liquid, which comprises: the tank body is provided with a cavity, and a sealing cover is arranged on the tank body; the liquid inlet pipe and the water outlet pipe are arranged on the outer wall of the tank body, and the liquid inlet pipe is used for receiving oil field produced liquid; and the air outlet pipe and the oil outlet pipe are arranged on the sealing cover, and the sewage discharge pipe is arranged at the bottom of the tank body. Wherein, an inner partition cylinder for enabling the oilfield produced fluid to form rotational flow is arranged in the inner cavity. The inner partition cylinder is in a round table shape, and the large-diameter end of the inner partition cylinder is connected to the inner wall of the tank body in a sealing mode and divides the inner cavity into a first inner cavity close to the small-diameter end of the inner partition cylinder and a second inner cavity close to the large-diameter end of the inner partition cylinder. The air outlet pipe, the oil outlet pipe and the water outlet pipe are communicated with the first inner cavity, and the liquid inlet pipe and the sewage discharge pipe are communicated with the second inner cavity.

Description

Oil field produced liquid water purification device

Technical Field

The utility model relates to a water quality purification device for oilfield produced liquid.

Background

Along with the annual increase of the extracted liquid volume of each oil field in China and the gradual increase of the water content in the extracted liquid, the operation load of a ground crude oil gathering and transportation system is larger and larger, the water quality purification flow of the extracted water is longer and longer, and great pressure is brought to field production operation and safety management. The existing separation generally comprises an inclined plate coalescence oil remover, a hydraulic cyclone, cyclone flotation, gravity settling tank sedimentation separation and the like.

The cyclone floating process is a new technology coupling the air floating process and the rotational flow process, and although the cyclone floating process has the advantages of less investment, small occupied area, high separation efficiency, no addition of medicament, no secondary pollution and the like compared with the traditional separation technology, oil drop particles with the particle size of less than 10 mu m cannot be separated, and the separation effect is limited.

The gravity settling tank occupies a large area, the required settling separation time is long, only floating oil with larger particle size can be separated, the separation efficiency is lower, and particularly, a larger settling tank cannot be built in places which are severely limited by space.

Although the hydrocyclone oil-water separation technology has a series of advantages of simple structure, high separation speed, small occupied area, no need of adding chemical reagents and the like, the oil drop particles generated by shearing oil drops due to the continuously increased flow velocity in the hydrocyclone field can bring serious negative effects on high-precision separation, and the hydrocyclone oil-water separation technology also becomes a restriction factor for popularization and application of the technology in oil fields and has very limited adaptability.

In the cyclone flotation technology, in order to enhance the effect of oil-water separation, a flotation agent is generally added into the oily wastewater before air flotation. However, the addition of the flotation agent not only increases the cost of water treatment, but also increases the complexity of water quality components, and is easy to generate secondary pollution.

SUMMERY OF THE UTILITY MODEL

Aiming at the technical problems, the utility model aims to provide a water quality purification device for oilfield produced fluid. The device has simple structure and small floor area; meanwhile, the device realizes the oil-water separation of the produced liquid by a physical method without using chemical agents; on the basis, the separation precision can be improved.

The water quality purification device for the oilfield produced fluid comprises a tank body with a cavity, wherein a sealing cover is arranged on the tank body; the liquid inlet pipe and the water outlet pipe are arranged on the outer wall of the tank body, and the liquid inlet pipe is used for receiving oil field produced liquid; and the air outlet pipe and the oil outlet pipe are arranged on the sealing cover, and the sewage discharge pipe is arranged at the bottom of the tank body.

Wherein, an inner partition cylinder for enabling the oilfield produced fluid to form rotational flow is arranged in the inner cavity. The inner partition cylinder is in a round table shape, and the large-diameter end of the inner partition cylinder is connected to the inner wall of the tank body in a sealing mode and divides the inner cavity into a first inner cavity close to the small-diameter end of the inner partition cylinder and a second inner cavity close to the large-diameter end of the inner partition cylinder. The air outlet pipe, the oil outlet pipe and the water outlet pipe are communicated with the first inner cavity, and the liquid inlet pipe and the sewage discharge pipe are communicated with the second inner cavity.

In a preferred embodiment, a passage communicating the first and second lumens is formed in the inner partition, and the passage is tapered so that a swirling flow of fluid is generated when fluid is passed through the passage under pressure.

In a preferred embodiment, the channel is arranged at an angle in the range of 60 ° to 75 ° to the horizontal.

In a preferred embodiment, the distance between one end of the channel, which is communicated with the first inner cavity, and the liquid inlet pipe in the vertical direction is set to be 50-75% of the distance between the liquid inlet pipe and the liquid outlet pipe in the vertical direction.

In a preferred embodiment, a hydrophilic oleophobic filter screen is hermetically sleeved on the outer wall of the inner partition cylinder above the water outlet pipe, and the periphery of the filter screen is hermetically connected with the inner wall of the tank body.

In a preferred embodiment, the liquid inlet pipe is provided as a venturi pipe, and an air inlet is further provided on an outer wall of the liquid inlet pipe.

In a preferred embodiment, the device further comprises a gas circulating pipe, and the two ends of the gas circulating pipe are respectively connected with the gas outlet pipe and the liquid inlet pipe.

In a preferred embodiment, a control valve and a gas flow meter are provided on the gas circulation pipe.

In a preferred embodiment, a safety valve communicated with the first inner cavity is further arranged on the tank body.

In a preferred embodiment, the can and the cover are connected by a flange

Drawings

The utility model will now be described with reference to the accompanying drawings.

Fig. 1 schematically shows a schematic diagram of an oilfield produced fluid water purification device according to the present invention.

In the present application, the drawings are all schematic and are used only for illustrating the principles of the utility model and are not drawn to scale.

Detailed Description

The utility model is described below with reference to the accompanying drawings.

Fig. 1 shows an oilfield produced water quality purification apparatus 100 according to the present invention. As shown in fig. 1, the oilfield produced water quality purification apparatus 100 includes a tank 10, and a cavity 20 for accommodating oilfield produced water is defined in the tank 10. A cover 15 is provided on the upper end of the can body 10. Preferably, the cover 15 is secured to the can body by a flange 18. The fixing mode ensures the air tightness of the connecting part of the can body 10 of the sealing cover 15 on one hand, improves the stability of the connection on the other hand, and effectively prevents the sealing cover 15 from being separated from the can body 10 under the action of high pressure in the can body.

As shown in fig. 1, an inner spacer 30 is disposed within the cavity 20. The inner partition 30 is of frustoconical design and has a conical wall 35. The large diameter end 32 (i.e., the end with the larger diameter) of the inner partition 30 is sealingly connected to the inner wall of the cavity 20, thereby dividing the cavity 20 into two parts, namely, a first interior 22 above the wall 35 and a second interior 24 below the wall 35. Meanwhile, the large-diameter end 32 and the small-diameter end (i.e., the end with the smaller diameter) 34 of the inner partition 30 are both formed as openings, and a tapered passage 38 is formed between the large-diameter end 32 and the small-diameter end 34 in the axial direction, so that fluid can enter the first inner cavity 22 from the second inner cavity 24 along the passage 38.

An inlet pipe 40 is disposed on the side wall of the tank 10, a first end 42 of the inlet pipe 40 is used for communicating with an oil outlet pipeline (not shown) of an oil field, and a second end 44 is communicated with the second inner cavity 24. The liquid inlet pipe 40 is used for introducing produced water in the oil field into the second inner cavity 24.

Meanwhile, the device 100 further comprises a gas inlet 45 communicated with the second inner cavity 24, wherein one end of the gas inlet 45 is connected with a gas source, and the gas source is used for introducing high-pressure gas into the second inner cavity 24. Thus, a gas-liquid mixture can be formed in the second inner cavity 24 through the combined action of the liquid inlet pipe 40 and the gas inlet 45. Preferably, the air inlet 45 is provided on the outer wall of the liquid inlet pipe 40. Through the arrangement, on one hand, the structure of the device 100 can be simplified, and on the other hand, the oil field produced water and the high-pressure gas can flow into the second inner cavity 24 together through the liquid inlet pipe 40, so that the high-pressure gas and the oil field produced water can be fully fused.

In a preferred embodiment, the liquid inlet pipe 40 is configured as a venturi. Thus, according to the venturi effect, as the oilfield produced water flows through the inlet pipe 40, its flow rate increases, thereby creating a negative pressure locally. This further facilitates the merging of gas and liquid in the inlet pipe 40.

When the gas-liquid mixture in the liquid inlet pipe 40 enters the second inner cavity 24, the gas-liquid mixture moves towards the first inner cavity 22 through the conical passage 38 in the inner partition cylinder 30 under the action of pressure. It will be readily appreciated that during movement, the gas-liquid mixture will swirl in the conical passage 38. On the other hand, since the pressure in the second inner cavity 24 is lower than the pressure in the liquid inlet pipe 40, when the gas-liquid mixture enters the second inner cavity 24, the gas in the mixture will be separated out, and further bubbles will be formed in the mixture. Meanwhile, by reasonably designing the angle of the inner partition cylinder wall body 38 and the height of the inner partition cylinder 30 or the position of the liquid inlet pipe 40, the centrifugal force of the rotational flow can be controlled, so that bubbles formed in the mixture are prevented from breaking. Thus, under the separation action of the rotational flow, the oil phase in the mixture can be attached to the bubbles formed in the liquid to form a low-density oil-gas mixture. When the mixture exits the tapered passage 38 and enters the first interior chamber 22, the mixture, due to its lower density, will tend to collect near the upper end of the closure cap 15. While the remaining liquid, being denser, will collect towards the lower end remote from the closure 15. Thereby, the oil phase and the liquid phase in the mixture are separated. During this separation, the solid impurities in the mixture settle down to the bottom of the can body 10.

In a preferred embodiment, the angle of the conical wall 35 of the inner partition 30 with the horizontal plane is set to 60 ° -75 °. Meanwhile, the height of the inner partition cylinder 30 or the position of the liquid inlet pipe 40 is set to ensure that the distance between the small-diameter end 34 of the inner partition cylinder 30 and the liquid inlet pipe 40 in the vertical direction is 50-75% of the distance between the liquid inlet pipe and the oil outlet pipe in the vertical direction. Practice has shown that with this arrangement, it is possible to avoid the formation of bubbles in the mixture from breaking while ensuring the separation effect.

As shown in fig. 1, an oil outlet pipe 26 and an air outlet pipe 28 are respectively disposed on the cover 15 and are communicated with the first inner cavity 22, and a water outlet pipe 29 communicated with the first inner cavity 22 is disposed on the side wall of the tank 10. Thus, when the mixture flows into the first chamber and the water phase and the oil phase are separated, the oil phase and the gas phase in the mixture are discharged to the outside of the tank 10 through the oil outlet pipe 26 and the air outlet pipe 28, respectively. The remaining liquid phase is discharged out of the tank 10 through the outlet pipe 29. Meanwhile, a sewage draining outlet 48 is formed at the bottom of the tank 10. The drain outlet 48 is preferably configured as a siphon inlet so that solid impurities having poor flowability can be more rapidly and thoroughly discharged out of the tank 10 by using a siphon effect.

In a preferred embodiment, the apparatus 100 further comprises a gas circulation tube 70. One end of the gas circulation pipe 70 is connected to the gas outlet pipe 28, and the other end is communicated with the gas inlet 45 on the outer wall of the liquid inlet pipe 40. Thus, when gas is discharged from the gas outlet 28, it re-enters the liquid inlet pipe 40 along the gas circulation pipe 70. Through the arrangement, the gas can be recycled, a new gas source is not required to be introduced, and the cost is reduced. Meanwhile, a control valve 72 and a gas flow meter 75 are provided on the gas circulation pipe 70. The gas flow meter 75 is used to monitor the gas flow in the pipeline, and the control valve 72 is used to control the on/off of the gas circulation pipe 70 or to regulate the gas flow in the gas circulation pipe 70.

In a preferred embodiment, as shown in fig. 1, a hydrophilic oleophobic screen 80 is also hermetically sleeved on the outer wall above the inner partition cylinder 30. Essentially, the hydrophilic and oleophobic screen 80 is disposed above the outlet pipe 29 and sealingly connected to the inner wall of the tank 10 so that the hydrophilic and oleophobic screen 80 can block the outlet pipe 26 and the outlet pipe 29. The hydrophilic oleophobic screen 80 has a selective permeability that allows only the aqueous phase of the liquid to pass through. Thus, when the liquid reaches the first interior cavity 22, the hydrophilic oleophobic screen 80 prevents oil phase that has not been separated sufficiently or has been re-mixed into the water phase from entering the exit port 29 below the hydrophilic oleophobic screen 80. Thus, the hydrophilic oleophobic filter screen 80 can play a role in secondary filtration and separation, and the separation precision of the device 100 is improved.

In addition, the device 100 includes a relief valve 90 in communication with the cavity 20. The safety valve can monitor the pressure change in the cavity 20 and automatically open after the pressure in the cavity 20 reaches a manually set threshold, thereby reducing the pressure in the cavity 20 and ensuring the safety of the entire device 100.

The following briefly describes the use of the oilfield produced water quality purification apparatus 100 according to the present invention.

The water quality purification device 100 for the produced water in the oil field is connected with an oil pipe of the oil field through a liquid inlet pipe 40. When the produced water in the oil field reaches the liquid inlet pipe 40, the control valve 75 on the gas circulation pipe 70 is firstly opened, and high-pressure gas is introduced into the liquid inlet pipe 40. At this time, the oilfield produced water accelerates to flow in the liquid inlet pipe 40 to form a negative pressure, so that a gas-liquid mixture is formed with the gas.

When the gas-liquid mixture enters the second inner cavity 24, gas in the gas-liquid mixture can be separated out to form bubbles due to the reduction of the pressure. As the gas-liquid mixture passes through the tapered passage 38 under pressure, it may swirl and create centrifugal force. Under the action of centrifugal force, solid impurities in the gas-liquid mixture are separated and deposited downwards to the bottom of the tank 10, and are discharged out of the tank 10 through a sewage discharge outlet 48 at the bottom of the tank 10. Meanwhile, the oil phase in the gas-liquid mixture is attached to the bubbles to form an oil-gas mixture with low density. The oil and gas mixture continues to move upward after passing through the tapered passage 38 until the oil phase and the gas phase therein are discharged from the flow line 26 and the gas outlet line 28, respectively.

At this point, the remaining denser water phase moves downward after passing through tapered channel 38, passes through the hydrophilic oleophobic screen 80 to outlet pipe 29, and exits tank 10 through outlet pipe 29. When the oil phase passes through the hydrophilic oleophobic filter screen 80, the hydrophilic oleophobic filter screen 80 can play a role in secondary filtration, and the oil phase which is not completely separated is prevented from reaching the water outlet pipe 29. So far, the whole process of purifying the water quality of the produced water of the oil field is finished.

Finally, it should be noted that the above-mentioned embodiments are only preferred embodiments of the present invention, and do not limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that modifications may be made to the embodiments described in the foregoing examples, or that equivalents may be substituted for elements thereof. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An oilfield produced fluid water purification device (100), comprising:

a can (10) defining a cavity (20) therein, on which a closure (15) is provided;

the liquid inlet pipe (40) and the water outlet pipe (29) are arranged on the outer wall of the tank body, and the liquid inlet pipe (40) is used for receiving oilfield produced liquid; and the number of the first and second groups,

an air outlet pipe (28) and an oil outlet pipe (26) which are arranged on the sealing cover, and a sewage outlet (48) which is arranged at the bottom of the tank body;

an inner partition cylinder (30) used for enabling oilfield produced fluid to form rotational flow is arranged in the cavity, the inner partition cylinder is in a circular truncated cone shape, a large-diameter end (32) of the inner partition cylinder is connected to the inner wall of the tank body in a sealing mode, and the cavity is divided into a first inner cavity (22) close to a small-diameter end (34) of the inner partition cylinder and a second inner cavity (24) close to the large-diameter end of the inner partition cylinder;

the air outlet pipe, the oil outlet pipe and the water outlet pipe are communicated with the first inner cavity, and the liquid inlet pipe and the drain outlet are communicated with the second inner cavity.

2. The oilfield produced fluid water purification device of claim 1, wherein a channel (38) communicating the first and second lumens is formed in the inner partition cylinder, the channel being tapered such that a swirling flow of fluid is created when fluid is forced through the channel.

3. The oilfield produced liquid water quality purification device of claim 2, wherein the channel is at an angle of 60 ° to 75 ° with respect to the horizontal plane.

4. The oilfield produced liquid water purification device of claim 3, wherein the vertical distance between one end of the channel, which is communicated with the first inner cavity, and the liquid inlet pipe is 50-75% of the vertical distance between the liquid inlet pipe and the oil outlet pipe.

5. The oilfield produced liquid water quality purification device according to any one of claims 1-4, wherein a hydrophilic oleophobic filter screen (80) is hermetically sleeved on the outer wall of the inner partition cylinder above the water outlet pipe, and the periphery of the filter screen is hermetically connected with the inner wall of the tank body.

6. The oilfield produced liquid water purification apparatus of any one of claims 1-4, wherein the liquid inlet pipe is provided as a venturi, and an air inlet (45) is further provided on an outer wall of the liquid inlet pipe.

7. The oilfield produced liquid water purification device according to any one of claims 1-4, further comprising a gas circulation pipe (70), wherein the two ends of the gas circulation pipe are respectively connected with the gas outlet pipe and the liquid inlet pipe.

8. The oilfield produced liquid water quality purification device according to claim 7, wherein a control valve (72) and a gas flow meter (75) are arranged on the gas circulation pipe.

9. An oilfield produced fluid water purification apparatus according to any one of claims 1-4, wherein a safety valve (90) defining the pressure of the first inner chamber is further provided on the tank.

10. The oilfield produced fluid water purification device of any one of claims 1-4, wherein the tank body and the cover are connected through a flange (18).