KR101490147B1 - Treating method of Produced Water - Google Patents

Abstract

The present invention relates to a production water treatment method for treating production water containing a large amount of oil generated at the time of crude oil extraction. More specifically, the present invention relates to a method for producing oil containing residual oil and gas component And a gas mixing step of mixing the produced water and the gas component so as to increase the separation efficiency between water and oil, and the hydrocyclone liner used in the oil component removing step To a production water treatment method capable of effectively removing oil from production water by improving the inner wall structure.

Description

{Treating method of Produced Water}

The present invention relates to a production water treatment method for treating production water containing a large amount of oil generated at the time of crude oil extraction. More specifically, the present invention relates to a method for producing oil containing residual oil and gas component And a gas mixing step of mixing the produced water and the gas component so as to increase the separation efficiency between water and oil, and the hydrocyclone liner used in the oil component removing step To a production water treatment method capable of effectively removing oil from production water by improving the inner wall structure.

Produced Water is Oily Wastewater which occupies the largest proportion among the wastes generated during the oil production process, and is essentially water entrapped in groundwater discharged to the earth surface during oil production. The production of one barrel of oil is about 7 to 10 barrels. These are highly toxic and usually contain oils, greases and other hydrocarbons, as well as large amounts of salts, metals and trace elements. Managing it can have significant environmental impacts and cost a lot (1).

The oil component extracted from the oil sands is heavy, sticky black viscous oil called bitumen, which accounts for about 10-12% of the oil sands (2). Since natural crude oil is lighter than water but bitumen has a similar weight to water, the bitumen does not flow in boreholes or pipelines in the natural state, so steam is added or diluent (ultra-hard crude oil or light petroleum product) Mixed and reduced in specific gravity and viscosity, and then transported to an oil pipeline. Because bitumen contains a large amount of water, it is necessary to separate the oil by using a primary separation FWKO (Free Water Knock-Out), a secondary separation as demulsifier chemicals, and an electric field (Electrostatic Field) (3, 4). The production water after the recovery of the oil component still contains a large amount of oil and solvent components, and in order to release or recycle it, the production water treatment process should be performed with water containing less than 5 ppm of oil.

The production water treatment methods are roughly classified into three types: physical treatment, biological treatment, and chemical treatment (5). Among them, the most widely used methods are physical treatment methods, and the methods with high separation efficiency are biological treatment methods and chemical treatment methods.

Physical treatment methods are the easiest and easiest methods to use, such as Filtration, Sorption, Gravity, Centrifugal force, Membrane, Distillation, Skimmer, (Flotation), and so on (6). The advantage is that it is easier to control than chemical or biological treatment techniques, and the disadvantage is that it is difficult to expect high separation efficiency with physical treatment technology.

In order to reliably remove the organic matter contained in the production water, methods using chemical reaction or biological reaction are additionally needed. Currently the most used techniques are filtration, sorption (adsorption / absorption) and gravity sedimentation. Filtration and sorption have the advantage that they can be obtained easily. Gravity settling is advantageous in that the drying cost of the apparatus is higher than that of filtration or sorption, but the maintenance cost is lower.

Biological treatment methods can be classified into microbial treatment methods and treatment methods using activated sludge. Methods of treatment with microorganisms can be divided into aerobic microbiology and anaerobic microbiology. Among biological treatment methods, aerobic microorganism treatment is most commonly used. Trickling filter, Sequencing Batch Reactor (SBR), and Biological Aerated Filter are some of the biological treatment methods. The anaerobic microbial treatment method is advantageous in cost efficiency when the concentration of the pollutant is low. The reed bed method is widely used and the average hydrocarbon separation efficiency is 96% at the production water treatment of 3,000 m3 / day (5,7).

Activated sludge is a type of aerobic microorganism that is one of the most used techniques in water treatment process. It is mainly used with the skimmer technology and it is known that it has a separation efficiency of about 98 ~ 99% at 20 days of Solids Retention Time (SRT) (5).

Chemical treatment methods include oxidation, coagulation, and demulsifier chemicals. In recent years, there has been a great deal of research on electrochemical processes and photocatalytic treatments using electricity. Research is underway (5).

Oxidation is mainly used to decompose refractory chemicals. Strong Oxidant, Catalyst, Irradiation, etc. are used. At present, AOP (Advanced Oxidation Process) technology is developed and commercialized, and AOP simultaneously generates ultraviolet wavelengths and ozone generating wavelengths in a discharge lamp, so that a large amount of OH radicals And oxidation treatment. Condensation is used to remove suspended solids and colloidal particles, and it is inefficient to remove dissolved substances (5, 10).

Korean Patent Publication No. 1999-0045521 (published June 25, 1999)

(1) Tellez, GT, Nirmalakhandan, N. and Gardea-Torresdey, JL, "Evaluation of Biokinetic Coefficients in Degradation of Oilfield Produced Water under Varying Salt Concentrations", Wat. Res., 29 (7), 1711-1718 ). (2) Park, Y. K., Choi, W. C., Jeong, S. Y. and Lee, C. W., "High Value Added Technology of Oilsands", Korean Chem. Eng. Res. (HWAHAK KONGHAK), 45 (2), 109-116 (2007). (3) Park, K., Han, S. D., Han, H. J., Kang, K. S., Bae, W. and Rhee, Y. W., "Technology Trend of Oil Treatment for Oilsands by the Patent Analysis ", CLEAN TECHNOLOGY, 15 (3), 210-223 (2009). (4) Park, K., Han, SD, Noh, SY, Bae, W. and Rhee, YW, "Characteristics of Separation of Water / Bitumen Emulsion by Chemical Demulsifier", CLEAN TECHNOLOGY, 15 (2009). (5) Fakhru'l-Razi, A., Pendashteh, A., Abdullah, LC, Biak, DRA, Madaeni, SS and Abidin, ZZ, "Review of Technologies for Oil and Gas Produced Water Treatment" , 170 (2-3), 530-551 (2009). (6) Murray-Gulde, C., Heatly, JE, Karanfil, T., Rodgers Jr., JH and Myers, JE, "Performance of a Hybrid Reverse Osmosis-Generated Wetland Treatment System for Brackish Oil Field Produced Water" , 37 (3), 705-713 (2003). (7) Xu, P., Drewes, JE, Heil, D. and Wang, G., "Treatment of Brackish Produced Water Using Carbon Aerogel-based Capacitive Deionization Technology", Water Res., 42 (10-11), 2605 -2617 (2008). (8) Cha, Z., Lin, C., Cheng, C. and Hong, PKA, "Removal of Oil and Oil Sheen from Produced Water by Pressure- assisted Ozonation and Sand Filtration", Chemosphere, 590 (2010). (9) McCormack, P., Jones, P., Hetheridge, MJ and Rowland, SJ, "Analysis of Oilfield Produced Waters and Production Chemicals by Electrospray Ionization Multi-Stage Mass Spectrometry (ESI-MSn) (15), 3567-3578 (2001). (10) Shpiner, R., Vathi, S. and Stuckey, DC, "Treatment of Oil Wells" Produced Water "by Waste Stabilization Ponds: Removal of Heavy Metals", Water Res., 43 (17), 4258-4268 2009).

It is an object of the present invention to solve the above problems, and it is an object of the present invention to provide a production water treatment method for treating production water containing a large amount of oil generated during crude oil collection, And to provide a production water treatment method capable of increasing the separation efficiency between water and oil.

It is also an object of the present invention to provide a production water treatment method capable of effectively removing oil from production water by improving the inner wall structure of a hydrocyclone liner corresponding to a core part for physically separating oil from production water .

In order to achieve the above object, the present invention provides a sand removing method for separating and removing a sand component from production water separated from crude oil; An oil removing step of separating and removing the oil component from the produced water from which the sand component is removed; And a gas removing step of separating and removing remaining oil and gas components from the produced water from which the oil component has been removed, wherein, in the production water treatment step, before the sand removing step or the gas removing step, And a gas mixing step of mixing the gas and the gas mixture.

In an embodiment of the present invention, it is preferable that mixing of the produced water and the gas component in the gas mixing step is performed at a higher pressure than in the gas removing step as a post-process. In another embodiment of the present invention, in order to increase the contact surface between the produced water and the gas component in the gas mixing step, it is preferable that turbulence is formed in the gas mixing tank in which the produced water and the gas component are mixed, It is preferable that the flow direction of the produced water and the gas inflow direction in the gas mixing tank are perpendicular to each other so that turbulent flow is formed in the gas mixing tank.

In an embodiment of the present invention, it is preferable that at least a part or more of the gas separated in the gas removing step is recycled as a gas component mixed with the produced water in the gas mixing step.

The hydrocyclone includes a hydrocyclone liner having a hollow structure, and the hydrocyclone liner is introduced into the hydrocyclone liner in a state where the production water containing the oil is introduced Introduction portion; An upper discharge portion through which the oil component having a relatively low specific gravity is discharged in the produced water; And a lower discharge portion through which the water component having relatively high specific gravity is discharged in the produced water.

 Wherein the upper discharge portion is located at the center of one end of the liner of the hollow structure and the lower discharge portion is located at the center of the other end of the opposite end of the hollow structure, A first region, a second region and a third region in which slopes of the inner wall of the liner from the one end of the liner to the other end of the liner where the lower discharge portion is located are different from each other.

An embodiment of the present invention is characterized in that i) the inner angle defined by the inner wall of the first region is 1.5 to 2 times larger than the inner angle defined by the inner wall of the second region, or ii) The slope is changed into an exponential function or a curve of a quadratic function type, and the production water containing the oil introduced through the inlet portion located in the first region is produced by the vortex generated by the centrifugal force, The oil component having a relatively low specific gravity is discharged through the upper discharge portion and the water component having a relatively high specific gravity in the production water flows through the lower discharge portion positioned in the third region through the second region located in the lower portion of the first region And is discharged.

If the maximum diameter of the inner wall of the liner in the first region is D _H , the maximum diameter of the inner wall of the liner in the second region is D _S , the diameter of the upper discharge portion is D ₀ and the diameter of the lower discharge portion is D _U , ? D ₀ / D _H ? 0.08, 0.4? D _S / D _H ? 0.6, and 0.2? D _U / D _H ? 0.3.

In one embodiment of the invention the size of the cabinet is defined by the inner wall of the first area may be a 30 ^o to 40 ^o, yet another embodiment of to the slope of the inner walls of the first region formula (1) , And (2), respectively.

(1)

(One)

(Note that an a value that affects the exponential slope in the first region has a value between 6 and 21, and a value in the longitudinal direction z ranges from 0 to 225).

(2)

(2)

(Where D denotes the diameter of the first region, and the value of the longitudinal direction z ranges from 0 to 225).

In another embodiment of the present invention, the slope of the inner wall of the first region may be changed into a polynomial function as shown in the following equation (3).

(3)

(3)

(Where D denotes the diameter of the first region, and the value of the longitudinal direction z ranges from 0 to 225).

In the second region, the liner inner wall (D _s ) preferably has a size of the inner angle (2b) ranging from 1.3 to 1.5 degrees, and the inner wall of the first region has a maximum diameter (D _H ) of 30 mm To 70 mm.

In another embodiment of the present invention, the cross-section of the introduction portion into which the production water containing the oil is introduced is preferably elliptical, and the ratio of the long axis to the short axis of the elliptical inlet portion is preferably 0.2 to 0.5.

The production water treatment method of the present invention is a production water treatment process for separating residual oil and gas components after removing a sand component and an oil component from production water separated from crude oil, Thereby increasing the separation efficiency between water and oil and reducing the size of the de-gassing drum.

In addition, the hollow structure of the hydrocyclone liner used in the oil removing step of the present invention has a larger centrifugal force than the conventional liner having a conventional single slope surface, so that the oil and water are more efficiently separated and the overall throughput can be increased have.

1 is a process diagram schematically showing a production water treatment system of the present invention.
2 is a conceptual diagram showing an embodiment of a gas mixing tank used in the gas mixing step of the present invention.
3 is an analysis of the flow values inside the gas mixing vessel used in the gas mixing step of the present invention.
4 is a diagram schematically illustrating a conventional liner structure.
Figures 5a-d schematically illustrate a liner structure according to each embodiment of the present invention.
6A and 6B are computational results of the center axis velocity, the pressure and the concentration distribution of the conventional liner structure (FIG. 6A) and the liner of the present invention (FIG. 6B).
7A and 7B show the distribution of the center axis velocity a and b and the tangential velocity distributions c and d of the liner structure of the present invention (Fig. 7A) and the liner of the present invention (Fig. c is z = 1/2 * Ds, b, d is z = Ds).
Fig. 8 is a result of computational simulation of the separation efficiency of the comparative example for each droplet size.
Fig. 9 shows the results of comparison of the separation efficiencies of the present invention and the comparative example when the droplet size is 30 mu m.
10A and 10B are results obtained by computer simulation of the central axis velocity distribution (FIG. 10A) and the tangential velocity distribution (FIG. 10B), respectively, for each of the embodiments of the present invention.
11 is a result of a comparison between the separation efficiencies of the various embodiments of the present invention and the comparative example in the case of a droplet size of 30 占 퐉.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of produced water including oil according to the present invention will be described with reference to the accompanying drawings, which may be easily carried out by a person having ordinary skill in the art to which the present invention pertains It should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, and thus are not limitative of the inventive concept and scope of the invention.

A typical production water treatment method is as follows. First, the production water separated from the crude oil in the separation tank 100 is subjected to a de-sanding and a de-oiling step, And is separated and removed. The production water in which the sand component and the oil component are separated and removed as described above is finally subjected to a gas removal step for separating and removing oil and gas components remaining in the produced water.

The degassing is performed in a degassing vessel such as a De-Gassing drum 400 where the gas component in the product water flowing into the degassing drum is discharged in the form of a bubble And is discharged to the flare gas line. At this time, the discharged gas attracts residual oil droplets and forms a thin oil layer at the interface, and the remaining oil at the interface is separated and discharged together with the gas to be reused.

The degassing drum 400 is designed to have a proper size according to the throughput of the produced water since the production water must be designed to be able to stay for at least a retention time for sufficient degassing of the produced water.

In order to improve the separation efficiency of oil and water in the degassing drum 400, as shown in FIG. 1A, before the sand removing step or the gas removing step, a gas And further comprising a mixing step.

The gas mixing step is performed in a gas mixing tank 500 using the principle of a pressurized flotation tank. The gas mixing tank 500 is an apparatus for accelerating the separation of oil and water. The gas mixing tank 500 mixes the liquid and the gas to saturate the gas in the liquid, thereby causing the degassing drum 400 to generate a larger amount of bubbles. .

As shown in FIG. 2, when the production water, which is a liquid, passes through the gas mixing chamber, the gas is introduced into the liquid through the gas inlet 510. As described above, the fluid into which the gas is introduced forms a turbulent flow as shown in FIG. 3, and the turbulent flow widens the contact surface between the liquid and the gas, so that a larger amount of gas is saturated with the liquid. At this time, the flow direction of the produced water and the gas flowing direction in the gas mixing tank are preferably perpendicular to each other such that turbulence is efficiently formed in the gas mixing tank 500.

In addition, the inside of the gas mixing chamber 500 is preferably maintained at a higher pressure than the degassing drum 400. A higher amount of gas may saturate into the liquid under high pressure conditions and the saturated gas may be discharged in a more efficient bubble form due to the large pressure difference in the degassing drum 400. [

At this time, the remaining oil is floated together with the bubble-shaped gas that is discharged, so that the water and the oil are separated. The separation efficiency between the water and the oil can be shortened by increasing the separation efficiency. In addition, since the retention time of the degassing drum 400 is reduced, the capacity, that is, the size of the degassing drum 400 can be reduced.

In addition, the gas supplied to the gas mixing tank 500 of the present invention can reduce environmental pollution by recycling the gas discharged from the degassing drum 400 to the flare gas.

Meanwhile, the sand removing step or the oil removing step of the present invention is preferably performed using a hydrocyclone. A hydrocyclone is a device that separates water and oil by generating a centrifugal force through rotational motion of the fluid, pushing the heavier water component outward, and the lighter oil component to the center of the cone.

Particularly, the liner of the DIILING HYDROCYCLONE 300 used in the oil removing step is a key component for physically separating oil from the produced water containing oil. It is common to be determined. In the present invention, the internal structure or internal shape of the liner is newly modified and optimized to further increase the oil separation efficiency.

First, a conventional liner structure is shown in FIG. Such a liner structure is a liner structure that the present applicant has developed and studied conventionally, and is not a known liner structure. As can be seen from FIG. 4, in the conventional liner, there is an inlet portion into which the produced water containing oil flows into the upper side of the liner, and the produced water flows down along the inner wall of the liner. A centrifugal force is generated.

Due to the difference in specific gravity between the oil component and water, the low specific gravity oil component is collected while forming a vortex at the center of the liner and discharged through the upper discharge portion existing above the inlet portion of the liner, Flows along the inner wall of the liner and finally discharged through the lower outlet.

In the conventional liner structure, a linear hollow region A1 in which the diameter does not change uniformly along the liner at the introduction portion, a first reduction region A2 in which the diameter of the constant angle 2a decreases, A second decreasing area A3 whose diameter is reduced to a more gentle angle 2b than the third area A4 and a third area A4 where the diameter is kept constant.

That is, the look relative to the inner diameter of the existing liner structure, and a constant diameter (D _H) for maintaining linear hollow regions (A1), the internal diameter decreasing constant while maintaining 2a angles have a diameter of D _S No. 1 decreased the area (A2), the first reduced region further to the reduction in diameter as a gentle slope a second reduced area compared to the (A3) (keeping the angle is 2b) and a diameter of the lower outlet portion diameter (D _U) And a third area A4 that is kept constant.

In contrast, the structure of the liner proposed in the present invention is similar to that of FIGS. 5A to 5D. Unlike the conventional liner of FIG. 4, the lower discharge portion is located at one end of the liner where the upper discharge portion is located A slope of the inner wall of the liner leading to the other end of the liner is divided into a first region, a second region and a third region which are different from each other.

Wherein the inner wall of the liner in the first region is i) the inner angle defined by the inner wall of the first region is 1.5 to 2 times larger than the inner angle defined by the inner wall of the second region, or ii) The slope of the inner wall of the region may be changed to an exponential function or a curved form of a quadratic function.

More specifically, the inner diameter defined by the inner wall of the first region may range from 30 ^o to 40 ^o, or a diameter (D) along the liner center axis in the direction from the upper discharge portion toward the lower discharge portion may satisfy the following formula ), (2), or a curved surface shape of a quadratic function such as the following equation (3).

(1)

(One)

(Wherein the a value affecting the exponential slope in the first region has a value between 6 and 21, and the value in the longitudinal direction z ranges from 0 to 225).

(2)

(2)

(Where D is the diameter of the first region and the value of the longitudinal direction z ranges from 0 to 225).

(3)

(3)

(Where D is the diameter of the first region and the value of the longitudinal direction z ranges from 0 to 225).

If the maximum diameter of the inner wall of the liner in the first region is D _H , the maximum diameter of the inner wall of the liner in the second region is D _S , the diameter of the upper discharge portion is D ₀ , and the diameter of the lower discharge portion is D _U , D ₀ / D _H ≤ 0.08, 0.4 ≤ D _S / D _H ≤ 0.6, and 0.2 ≤ D _U / D _H ≤ 0.3. The inner diameter D of the liner inner wall in the second region is selected in the range of 1.3 to 1.5 degrees and the maximum diameter D _H of the inner wall of the first region is in the range of 30 mm to 70 mm .

It is also preferred that the cross-section of the lead-in portion into which the product water containing the oil is introduced is introduced into the liner through which a fluid containing an oil can effectively flow through the inner wall of the liner, , The ratio of the long axis to the short axis of the elliptical inlet portion is preferably 0.2 to 0.5.

Hereinafter, the oil separating performance of the conventional liner structure divided into four regions and the liner structure of the present invention divided into three regions will be described in detail.

[Example 1]

First, in order to compare the performance of the liner structure of the present invention with the performance of the conventional liner structure, flow characteristics of the oil component and the water component in the liner structure were analyzed through computer simulation. Since the separation of water and oil is mainly caused by the vortex generated when the mixture of oil and water flows down along the liner tube wall, as mentioned above, the area of the last lower outlet portion where the effect of the vortex is relatively low Both liner were made identical.

Also, the liner structure of the present invention has a portion where the diameter is constantly maintained only at a portion communicating with the introduction portion, and a first region where the inner wall of the liner has a curved shape of an exponential function and is decreased from below the portion communicating with the introduction portion. Respectively. The concrete structure of the sheath liner used at this time is shown in Table 1 below.

The liner structure of the present invention (embodiment) Conventional liner (comparative example) DH (maximum diameter of the first region) 60 mm 60 mm DU (diameter of bottom discharge part) 15 mm 15 mm DS (maximum diameter of the second area) 30 mm 30 mm D0 (diameter of upper discharge portion) 4.2 mm 4.2 mm L1 (length of the first area) 90 mm 16 mm LH (total liner length) 1416 mm 1392 mm The slope of the first region

2a = 20 ^o The slope of the second region 2b = 1.5 [deg.] 2b = 1.34 [deg.] Introduction area 5.517x16 5.517x16

6A and 6B are computational results of the central axis velocity, the pressure and the concentration distribution of the comparative example (a) of the conventional liner structure and the embodiment (b) of the liner structure of the present invention, respectively.

In the conventional liner structure shown in FIG. 6A, it can be seen that there exists a region having a positive (+) center axial velocity at the upper end of the liner center, and the concentration distribution of the oil component in the liner is slightly different depending on the oil droplet size It can be seen that the larger the size of the droplet is (50 μm), the higher the concentration in the vicinity of the upper discharge portion, and the lower the droplet size in the lower discharge portion, the higher the concentration is (30 μm) .

6B, which is a result of the computer simulation of the liner structure of the present invention, it can be seen that the length of the region in which the center axial velocity is positive is longer than that of the conventional liner structure, , Which means that the oil component with low specific gravity can be discharged more efficiently through the upper discharge portion. Also, it can be seen that the concentration distribution of the oil component also has the highest concentration point in the region of the upper discharge portion, and as a whole, the liner structure of the present invention is more effective in separating the oil component than the conventional liner structure.

7A and 7B show the distribution of the central axis velocity and the tangential velocity distribution of the liner of the present invention (FIG. 7A) and the liner of the present invention (Z = 1/2 * D _S , Z = D _S ). It can be seen that the liner structure of the present invention having a reduced diameter in the form of an exponential function of the present invention has a relatively large central axis velocity in comparison with a conventional liner structure in which the diameter is reduced at a constant slope (or a certain angle) It can be seen that the difference in the speed increases as the distance to the bottom of the first area (i.e., closer to the second area) increases. In addition, it was confirmed that the liner of the present invention is also better in the tangential velocity distribution along with the central axial velocity distribution.

Fig. 9 shows the liner separation efficiencies of the present invention and the comparative example when the droplet size is 30 mu m as a result of comparing the liner separation efficiency according to the droplet size in the case of using the conventional liner structure as a comparative example to be.

As shown in FIG. 8, it was confirmed that all of the results converge at a constant separation efficiency within about 2 seconds. As the size of the droplet increases, the separation efficiency is improved. In the case of the droplet of about 50 μm, .

In order to compare the separation efficiencies of the oil droplets of the liner of the present invention, the comparison was made for the case of droplets having a size of 30 mu m as shown in Fig. 9. The liner structure in which the diameter decreases in the form of the exponential function of the present invention is constant It was confirmed that the separation efficiency was improved by about 8.7% with respect to the droplet of 30 mu m in comparison with the conventional liner structure in which the diameter was reduced by the inclination.

[Example 2]

Based on the results of the computer simulation, an experiment was conducted to fabricate a liner structure having a reduced diameter in the form of an exponential function having the same structure as in Example 1, and to remove oil components from the produced water containing oil The specific experimental conditions and the oil removal efficiency are shown in Tables 2 and 3 below.

In the actual separation experiment, the cross-sectional structure of the introduction part introducing the production water containing oil was changed to the elliptical shape instead of the rectangular shape, unlike the first embodiment 1. In this case, the ratio of the major axis to the minor axis of the elliptical type inlet was in the range of 0.2 to 0.5 Respectively.

By thus changing the cross-section of the inlet section to an elliptical shape, Produced water containing more oil can be introduced into the liner through which fluid, including oil, can flow effectively through the inner wall of the liner There are advantages.

Experiment No. Introduction flow
Q _F The lower discharge portion
Flow rate Q _U The upper discharge portion
Flow rate Q ₀ Inlet pressure
P _F The lower discharge portion
Pressure _PU The upper discharge portion
Pressure P _O One 57.34 53.78 3.56 4.02 1.83 0.24 2 57.18 53.38 3.8 4.04 1.84 0.27 3 57.22 53.41 3.81 4.05 1.86 0.24

Experiment No. Intake oil concentration [ppm] Lower outlet oil concentration [ppm] Separation efficiency [%] One 5721.6 432.9 0.92 2 3618.4 298.1 0.92 3 3555.2 275.5 0.92

In Table 2, the volume flow rate Q is in units of liter / min, the unit of pressure is bar, and the pressure drop ratio (PDR) is varied while changing the flow ratio Q ₀ / Q _H in the range of 0.06 to 0.07. Were all held at 1.7.

The separation efficiency of the oil components observed through these experiments was defined as the value obtained by dividing the oil concentration at the lower outlet by the inlet oil concentration minus 1. From the results of Table 3, %, Respectively.

[Example 3]

In order to compare the performance of the liner structure of the present invention with that of the conventional liner structure, flow characteristics of the oil component and the water component in the liner structure were analyzed through computer simulation. Since the separation of water and oil is mainly caused by the vortex generated when the mixture of oil and water flows down along the liner tube wall, as mentioned above, the area of the last lower outlet portion where the effect of the vortex is relatively low Both liner were made identical.

The liner structure in the embodiment has a first region where the diameter of the inner wall of the liner is reduced as shown in the following table from a portion communicating with the introducing portion, Designed to have

The concrete structure of the sheath liner used at this time is shown in Table 4 below, and specific shapes are shown in Figs. 5a to 5d, respectively. The conventional liner structure used as a comparative example is shown in Fig. 4 as mentioned above.

Structure Example 1 Structure Example 2 Structural Example 3 Structural Example 4 Conventional liner DH (maximum diameter of the first region) 60 mm 60 mm 60 mm 60 mm 60 mm DU (diameter of bottom discharge part) 15 mm 15 mm 15 mm 15 mm 15 mm DS (maximum diameter of the second area) 30 mm 30 mm 30 mm 30 mm 30 mm D0 (diameter of upper discharge portion) 4.2 mm 4.2 mm 4.2 mm 4.2 mm 4.2 mm L1 (length of the introduction region) 16 mm 16 mm 16 mm 16 mm 90 mm LH (total liner length) 1473 mm 1472.9 mm 1473 mm 1473 mm 1392 mm The slope of the first region 2a = 30 [deg.] 2a = 40v Equation (2) Equation (3) 2a = 20 [deg.] The slope of the second region 2b = 1.34 [deg.] 2b = 1.34 [deg.] 2b = 1.34 [deg.] 2b = 1.34 [deg.] 2b = 1.34 [deg.] Inlet area (mm ² ) 5.517x16 5.517x116 5.517x116 5.517x116 5.517x116

In this case, for convenience of computer simulation, the introduction part is a rectangle-shaped structure such as 5.517 ㅧ 16 mm ² , but in the actual experimental stage (Example 4), the ratio of the long axis to the short axis is 0.2 to 0.5, Respectively.

10A, it can be seen that the difference in the central axis velocity occurs in Structural Examples 1 to 4. Structural Example 3-Structural Example 4-Structural Example 2-Structural Example 1 , And it was slightly changed according to the shape of the convergent part. 10B, which observed the tangential velocity, it was confirmed that each of Structural Examples 1 to 4 slightly varied, but showed almost similar tendency, and the maximum tangential velocity was about 11 m / sec.

11 shows the results of comparative observation of the liner separation efficiencies of Structural Examples 1 to 4 of the present invention in comparison with the conventional liner structure of Comparative Example and the liner structure having the inner wall of the exponential function of Example 1. Fig.

11, it was confirmed that all of the results converge at a constant separation efficiency within about 2 seconds. In the case of the conventional liner structure, the separation efficiency converged to 83.1% and the liner of Example 1 was separated to 91.7% The efficiency is improved.

In the case of Structural Examples 1 to 4 of the present invention, although there is a slight difference in time to reach the final convergence value, the final convergence value of the separation efficiency reached 97.0% Which is significantly improved compared to that of the conventional method.

[Example 4]

Based on the results of such computational simulation, a liner structure having a reduced diameter in the form of an exponential function having the same structure as those of Structural Examples 1 to 4 was prepared, and an oil component was removed from the produced water containing oil Respectively. The inlet flow rate (Q _F ) and inlet pressure (P _F ) were fixed at 57 liter / min and 4.0 bar, respectively, while maintaining the ratio of the upper outlet Q _o to the lower outlet Q _H at 0.07. , The separation efficiency of the liner of Structural Examples 1 to 4 was measured.

In the actual separation experiment, the cross-sectional structure of the introduction part introducing the production water containing oil was changed to the elliptical shape instead of the rectangular shape, unlike the previous example 3. In this case, the ratio of the major axis to the minor axis of the elliptical type inlet was in the range of 0.2 to 0.5 Respectively.

By thus changing the cross-section of the inlet section to an elliptical shape, Produced water containing more oil can be introduced into the liner through which fluid, including oil, can flow effectively through the inner wall of the liner There are advantages.

The separation efficiency of the oil component was defined as a value obtained by dividing the value obtained by dividing the lower outlet oil concentration by the inlet oil concentration by 1 and the separation efficiency of the oil component in Structural Examples 1 to 4 with respect to the actual production water was as shown in Example 2 Separation efficiency of liner structure was about 5% higher than that of 92%.

The present invention is not limited to the above-described specific embodiments and descriptions, and various modifications can be made to those skilled in the art without departing from the gist of the present invention claimed in the claims. And such modifications are within the scope of protection of the present invention.

100: Separation tank 200: Desansing hydrocyclone
300: Deoiling hydrocyclone 400: De-Gassing drum
500: gas mixing tank 510: gas inlet

Claims (16)

A sand removing step of separating and removing the sand component from the production water separated from the crude oil; An oil removing step of separating and removing the oil component from the produced water from which the sand component is removed; And a gas removing step of separating and removing residual oil and gas components from the produced water from which the oil component has been removed,
Further comprising a gas mixing step of mixing the produced water and the gas component before the sand removing step or the gas removing step,
The sand removing step or the oil removing step is performed using a hydrocyclone,
Wherein the hydrocyclone comprises a hollow cyclone liner,
Wherein the hydrocyclone liner comprises: an introduction portion into which production water containing the oil is introduced; An upper discharge portion through which the oil component having a relatively low specific gravity is discharged in the produced water; And a lower discharge portion through which the water component having relatively high specific gravity is discharged in the produced water,
Wherein the upper discharge portion is located at the center of one end of the liner of the hollow structure and the lower discharge portion is located at the center of the other end of the opposite end of the hollow structure,
A first region, a second region, and a third region in which inclination of the inner wall of the liner is different from one end of the liner where the upper discharge portion is located to the other end of the liner where the lower discharge portion is located,
i) the inner angle defined by the inner wall of the first region is 1.5 to 2 times larger than the inner angle defined by the inner wall of the second region, or ii) the slope of the inner wall of the first region has an exponential function Or a quadratic function form,
The produced water containing oil introduced through the inlet portion located in the first region is discharged through the upper outlet portion due to the vortex generated by centrifugal force and the oil component having a relatively low specific gravity in the produced water is discharged through the upper outlet portion, Wherein a water component having a relatively high specific gravity is discharged through a lower discharge portion located in a third region through a second region located below the first region. The method according to claim 1,
Wherein the mixing of the produced water and the gas component in the gas mixing step is performed at a higher pressure than in the gas removing step which is a post-process. The method according to claim 1,
Wherein a turbulent flow is formed in a gas mixing tank in which the produced water and the gas component are mixed to increase the contact surface between the produced water and the gas component in the gas mixing step. The method of claim 3,
Wherein a flow direction of the produced water in the gas mixing tank and a flowing direction of the gas perpendicularly cross each other so that turbulent flow is formed in the gas mixing tank. The method according to claim 1,
Wherein at least a part of the gas separated in the gas removing step is recycled as a gas component mixed with the produced water in the gas mixing step. delete delete The method according to claim 1,
If the maximum diameter of the inner wall of the liner in the first region is D _H , the maximum diameter of the inner wall of the liner in the second region is D _S , the diameter of the upper discharge portion is D ₀ , and the diameter of the lower discharge portion is D _U ,
_{0.03 ≤ D 0 / D H ≤} 0.08, 0.4 ≤ D S / D H ≤ 0.6, the production process can be characterized in that that satisfies _{0.2 ≤ D U / D H ≤} 0.3. The method according to claim 1,
Characterized in that the size of the interior angle defined by the inner wall of said first region is between 30 [deg.] And 40 [deg.]. The method according to claim 1,
The diameter D of the inner wall of the liner in the first region having the curved shape of the exponential function is changed in the longitudinal direction z along the liner center axis from the upper discharge portion to the lower discharge portion as shown in the following equation Wherein said process water is treated as a product water.

(One)
Here, the a value affecting the exponential slope in the first region has a value between 6 and 21, and the value in the longitudinal direction z ranges from 0 to 225. The method according to claim 1,
Wherein the slope of the inner wall of the first region changes in an exponential function form as shown in the following equation (2).

(2)
Here, D means the diameter of the first region, and the value of the longitudinal direction z ranges from 0 to 225. The method according to claim 1,
Wherein a slope of the inner wall of the first region is changed into a polynomial function form as shown in the following equation (3).

(3)
Here, D means the diameter of the first region, and the value of the longitudinal direction z ranges from 0 to 225. The method according to claim 1,
Wherein the inner wall (D _S ) of the liner in the second region has a size of the inner angle (2b) ranging from 1.3 to 1.5 degrees. The method according to claim 1,
Wherein the maximum diameter D _H of the inner wall of the liner in the first region is from 30 mm to 70 mm. The method according to claim 1,
Wherein a cross-section of an inlet portion into which the produced water containing the oil is introduced is elliptical. The method according to claim 1,
Wherein the ratio of the long axis to the short axis of the elliptical inlet portion is 0.2 to 0.5.

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