Multi-micropore high-precision filtration device for treating oil-containing sewage of oil field

Abstract

The invention discloses a microporous high-precision filtration device for treating oil-containing sewage in an oil field, and relates to an oil-containing sewage treatment device in the oil field, a water inlet pipe and a water outlet pipe are respectively arranged on an upper sealing head and a lower sealing head of a tank body, a high-strength bearing pore plate is fixed at the lower part in the tank body, and a large-flux sand-blocking sieve plate is fixed on the high-strength bearing pore plate; a microporous ceramic filter material layer is laid on the large-flux sand blocking sieve plate; an anti-blocking water distributor is arranged in the upper sealing head, one end of a water outlet pipe penetrates through the bottom of the tank body and is arranged below the high-strength bearing pore plate, a plurality of water distribution branch pipes are uniformly arranged on the periphery of the outer wall of the water outlet pipe, and a plurality of through holes I are formed in the water distribution branch pipes; and a plurality of layers of high-frequency gas scrubbing devices are arranged in the microporous ceramic filter material layer. The device can improve the scale capacity, reduce the lift of the backwashing pump, improve the filtering precision, reduce the daily operation and maintenance cost, effectively enable all filter materials in the whole filter bed to be thoroughly cleaned without dead angles, and effectively avoid the phenomena of material leakage and pressure building during backwashing.

Description

Technical Field

[0001] The invention relates to a process for treating oilfield oily wastewater, and in particular to a multi-microporous high-precision filtering device for treating oilfield oily wastewater. Background Art

[0002] As oilfields gradually begin implementing ASP flooding, the quality of produced fluids has become completely different from that of water-flooded produced fluids. They are gradually exhibiting characteristics such as complex water composition, extreme stability, difficulty breaking emulsions, reduced surface tension, decreased ability of oil droplets to coalesce, high raw water viscosity, decreased ability of oil droplets to float, difficulty removing oil, difficulty settling suspended solids, and difficulty removing suspended solids. Produced fluids rarely meet ideal water quality requirements after traditional treatment processes, placing higher demands on existing oily wastewater treatment processes. However, current general processes do not have any specific design for ASP produced fluids, necessitating the design of more advanced treatment devices tailored to the water quality characteristics of ASP produced fluids.

[0003] The existing oily wastewater treatment process in oil fields is widely used in the treatment of oily wastewater in oil fields. However, in the actual production operation process, there are often a series of problems such as filter media compaction, backwash pressure buildup, backwash material leakage, incomplete filter media cleaning, and it is difficult for the treated water to meet the ideal water quality requirements. At the same time, there are also disadvantages such as water and electricity consumption and large floor space occupation, which leads to reduced production efficiency and increased production costs. Summary of the Invention

[0004] In order to solve the deficiencies of the prior art, the present invention provides a multi-microporous high-precision filtration device for treating oilfield oily wastewater.

[0005] The present invention provides a multi-microporous high-precision filtration device for treating oily wastewater in oil fields, which is composed of a tank body, the lower head of the tank body is seated on a supporting cylinder, and a water inlet pipe and a water outlet pipe are respectively provided on the upper head and the lower head thereof, a high-strength supporting orifice plate is fixed to the lower part of the tank body, a large-flux sand-blocking sieve plate is fixed on the high-strength supporting orifice plate, and a multi-microporous ceramic filter material layer is laid on the large-flux sand-blocking sieve plate; an anti-blocking water distributor is provided in the upper head corresponding to the water inlet pipe, one end of the outlet pipe passes through the bottom of the tank body, is placed below the high-strength supporting orifice plate, and a plurality of water distribution branches are evenly provided around its outer wall, and a plurality of through holes I are provided on the water distribution branches; a multi-layer high-frequency gas scrubbing device is provided in the multi-microporous ceramic filter material layer; the anti-blocking water distributor is composed of a sand-blocking screen cylinder and a sand-guiding sand-blocking sieve cap, the upper end of the sand-blocking sieve cylinder is fixed to the inner wall of the top end of the tank body, and the lower end is fixed to the sand-guiding sand-blocking sieve cap through a flange.

[0006] As a further improvement of the present invention, the sand-blocking screen cylinder is composed of an annular sand-blocking screen I fixed integrally with the outer circumference of a high-strength water-distributing liner pipe, and a plurality of through holes II are evenly distributed on the high-strength water-distributing liner pipe.

[0007] As a further improvement of the present invention, the sand-guiding and sand-blocking screen cap is composed of an inner high-strength water-distributing lining cap and an outer covered sand-blocking screen Ⅱ fixed together, and the high-strength water-distributing lining cap is provided with a plurality of through holes Ⅱ.

[0008] As a further improvement of the present invention, the sand-guiding and sand-blocking screen cap is an inverted truncated cone structure, the upper end opening of which is fixed to and communicated with the sand-blocking screen cylinder, and the lower end is blocked by a blocking plate.

[0009] As a further improvement of the present invention, the laying thickness of the microporous ceramic filter material layer is 2.5 to 3 meters.

[0010] As a further improvement of the present invention, the multi-layer high-frequency gas scrubbing device includes an air distribution main pipe and an air distribution branch pipe. One end of the air distribution main pipe passes through a high-strength supporting orifice plate and a large-flux sand-blocking screen plate and is placed in a multi-porous ceramic filter material layer. More than one layer of air distribution branch pipes is provided around the outer wall of the air distribution main pipe, and more than one through hole III is provided on the air distribution branch pipe. A sand-blocking air distribution cap is provided on the through hole III. The air inlet end of the air distribution main pipe is placed outside the tank body.

[0011] As a further improvement of the present invention, a through hole IV is provided on the outer wall of the support tube, and one end of the water outlet pipe and the air distribution main pipe passes through the through hole IV and is placed outside the support tube.

[0012] The present invention discloses a multi-microporous high-precision filtration device for treating oilfield oily wastewater, which is specially designed for the current ternary produced liquid. The multi-microporous high-precision filtration device is adopted in the process, which can increase the scale holding capacity, reduce the backwash pump head, improve the filtration accuracy, and reduce the daily operation and maintenance costs; the multi-layer high-frequency gas scrubbing device has the characteristics of low gas washing intensity and high frequency, gas saving, and uniform gas distribution, which can effectively ensure that all filter materials in the entire filter bed are thoroughly cleaned without dead corners; the anti-blocking water distributor can effectively avoid the phenomenon of backwash material leakage and pressure holding; the effluent water quality in the entire sewage treatment process reaches the "double 10" index of oil and suspended solids, so as to meet the water inlet requirements of the subsequent nano-level filtration section, and the effluent of the nano-level filtration section can reach the "5, 5, 2" index required for deep treatment of oily sewage. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a cross-sectional view of the structure of the multi-microporous high-precision filtration device of the present invention; Figure 2 This is a schematic structural diagram of the anti-blocking water distributor of the present invention; Figure 3This is a structural cross-sectional view of the sand-guiding and sand-blocking screen cap of the present invention; Figure 4 This is a schematic structural diagram of the multi-layer high-frequency gas scrubbing device of the present invention; Figure 5 This is a schematic diagram of the high-strength supporting orifice plate, large-flux sand-blocking screen plate and water outlet pipe structure of the present invention; Figure 6 The present invention is a process flow chart for treating oily wastewater using the multi-microporous high-precision filtration device of the present invention. DETAILED DESCRIPTION

[0014] The present invention provides a multi-microporous high-precision filtration device for treating oily wastewater in oil fields, which is composed of a tank body 1, the lower head of the tank body 1 being seated on a support tube 2, and a water inlet pipe 7 and a water outlet pipe 8 being respectively provided on the upper and lower heads of the tank body 1, more than two annular water-blocking baffles 25 being spaced apart on the lower part of the inner wall of the vertical section of the tank wall of the tank body 1, and an inspection hole being provided on the outer wall of the vertical section of the tank wall of the tank body 1; a through hole IV19 being provided on the outer wall of the support tube 2, one end of the water outlet pipe 8 passing through the through hole IV19 and being placed outside the support tube 2, the other end passing through the bottom of the tank body 1 and being placed below the high-strength supporting orifice plate 3, and a plurality of water distribution branch pipes 9 being evenly provided around its outer wall, and a plurality of through holes I10 being provided on the water distribution branch pipes 9.

[0015] A high-strength supporting orifice plate 3 is fixed to the lower part of the tank body 1, and a large-flux sand-blocking screen plate 4 is fixed on the high-strength supporting orifice plate 3. A multi-porous ceramic filter material layer 5 is laid on the large-flux sand-blocking screen plate 4. The particle size of the multi-porous ceramic filter material layer 5 is 1 to 3 mm, the porosity is greater than 40%, the breakage rate is less than 4%, and the laying thickness is 2.5 to 3 meters. It has high filtration accuracy and surface adsorption capacity, which can ensure stable effluent water quality. The multi-porous ceramic filter material used in this device is made of high-quality kaolin, binders, pore-forming agents, corrosion inhibitors, etc., which are calcined at high temperature. The uniqueness of the production process ensures a 10-year service life of the filter material, and the breakage rate is low, less than 1%. Its hard surface, crisscrossing internal porous network, high porosity, and strong adsorption force make the filter material non-caking and non-adhesive, and 100% recovery performance after backwashing. Compared with the traditional double-layer filter canister process, it has many innovations, improved indicators, shortened and simplified filtration process, and backwash can save energy by up to 50% and water by up to 70%. Because the filter media contains pores of different sizes and rough surfaces, during the filtration process, the pore sizes and gaps of the filtration micropores on each layer are different, so that the filter channels and gaps are not straight but curved, giving it the function of deep filtration or container filtration. When flowing through the changing channels and gaps, impurities larger than the average diameter are blocked outside the pores, and impurities smaller than the average pore diameter and gaps enter the channels. In each local area, the size of the pores and gaps varies, causing the flow rate of the medium to change accordingly. In addition, the irregular changes in the channels and gaps cause some impurities smaller than the pore diameter to be intercepted and adsorbed by the side walls. The adsorbed impurities further increase the surface area and structural complexity of the filter media, so that even finer impurities can be adsorbed, thereby greatly improving the filtration accuracy of the multi-microporous high-precision filtration device and achieving excellent filtration effects. At the same time, the "microporous ceramic material" filter medium used has a light specific gravity and does not require a backwash pump with a large flow and large lift, which saves one-time investment and reduces daily operation and maintenance costs. In addition, the microporous ceramic filter material has the interception accuracy of membrane filtration and the simple structure and easy maintenance and operation characteristics of traditional sand filtration. The unique sintering process and surface coating process of this filter medium enable the filter material to ensure the water quality when the incoming water fluctuates greatly, and it can still restore its original working state after suffering a system shock. The microporous ceramic filter material has the characteristics of large specific surface area, strong pollution interception ability, high water output, stable water quality, and long filtration cycle.

[0016] An anti-blocking water distributor 6 is provided in the upper head of the tank body 1, corresponding to the water inlet pipe 7. The anti-blocking water distributor 6 is composed of a sand-blocking screen cylinder 12 and a sand-guiding sand-blocking screen cap 13. The upper end of the sand-blocking screen cylinder 12 is fixed to the inner wall of the top end of the tank body 1, and the lower end is fixed with the sand-guiding sand-blocking screen cap 13 through a flange. The sand-blocking screen cylinder 12 is composed of an annular sand-blocking screen mesh Ⅰ20 fixed integrally with the outer circumference of a high-strength water-distributing liner pipe 14. The high-strength water-distributing liner pipe 14 can support the sand-blocking screen cylinder 12. A plurality of through holes Ⅱ15 are evenly distributed on the high-strength water-distributing liner pipe 14. The size of the through holes Ⅱ15 can be adjusted according to the processing volume. The sand-guiding and sand-blocking screen cap 13 is an inverted truncated cone structure with a larger upper portion and a smaller lower portion. It is composed of an inner high-strength water-distributing liner cap 22 and an outer sand-blocking screen mesh II 21 fixed together. The high-strength water-distributing liner cap 22 has the same shape as the sand-blocking screen mesh II 21 and is uniformly provided with multiple through-holes II 23. The upper opening of the sand-guiding and sand-blocking screen cap 13 is fixed and connected to the sand-blocking screen drum 12, and the lower end is blocked by a baffle plate 24. The high-strength steel lining and the funnel-shaped sand-guiding and anti-blocking screen plate ensure uniform water distribution, effectively preventing backwash material leakage and pressure buildup.

[0017] A multi-layer high-frequency gas scrubbing device 11 is provided within the microporous ceramic filter layer 5. The multi-layer high-frequency gas scrubbing device 11 comprises an air distribution main pipe 16 and an air distribution branch pipe 17. One end of the air distribution main pipe 16 passes through a high-strength support plate 3 and a high-throughput sand-blocking screen plate 4, respectively, and is placed within the microporous ceramic filter layer 5. Two layers of air distribution branch pipes 17 are provided around the outer wall of the air distribution main pipe 16. Each of the air distribution branch pipes 17 is provided with one or more through-holes III, each of which is equipped with a sand-blocking air cap 18. The air inlet end of the air distribution main pipe 16 passes through through-hole IV 19 and is placed outside the support tube 2. The multi-layer high-frequency gas scrubbing design offers low washing intensity, high frequency, gas savings, and uniform air distribution, effectively and thoroughly cleaning the filter media throughout the filter bed, eliminating dead corners. The filter media backwash cycle can be up to 72 hours.

[0018] The pores on the annular sand blocking screen I20, sand blocking screen II21 and large flux sand blocking screen plate 4 are smaller than the particle size of the microporous ceramic filter material, which can prevent the microporous ceramic filter material from being lost from the pores during the backwash process, resulting in waste of the microporous ceramic filter material.

[0019] During sewage treatment, the sewage that has been homogenized, reduced in viscosity, and has had its surface floating oil and some emulsified oil removed is injected into the intermediate water tank. The sewage at the outlet of the intermediate water tank is pumped from the water inlet pipe 7 into the multi-porous high-precision filtration device, and is evenly distributed through the anti-blocking water distributor 6. The forward flow passes through the multi-porous ceramic filter material layer 5 for filtration. The oil and suspended matter in the oily sewage are intercepted and adsorbed by the multi-porous ceramic filter material. The water filtered through the multi-porous ceramic filter material layer 5 passes through the large-flux sand-blocking sieve plate 4 and the high-strength supporting orifice plate 3 and is discharged from the outlet pipe 8. The device adopts the method of "multi-stage high-frequency gas scrubbing + water flushing" for backwashing. When backwashing, water with a certain pressure enters from the outlet pipe 8, flows out from the through hole Ⅰ 10, passes through the high-strength supporting plate 3 and the large-flux sand-blocking screen plate 4, and passes through the entire filter layer from the bottom of the microporous ceramic filter layer 5 in the reverse direction, so that the filter layer is in an expanded state, which can first flush out some easily flushed pollutants, and then, air is distributed from the air distribution main pipe 16 into the microporous ceramic filter layer 5, and the microporous ceramic filter layer 5 is scrubbed with high-frequency gas, and finally The multi-porous ceramic filter layer 5 is cleaned thoroughly, and the sewage after backwashing will be discharged from the water inlet pipe 7 through the anti-blocking water distributor 6. The anti-blocking water distributor 6 can effectively prevent the loss of the multi-porous ceramic filter material during backwashing, and there will be no backwashing blockage; the multi-stage high-frequency gas-water combined backwashing mechanism can reduce the gas supply pressure of the air supply unit, reduce the one-time investment and operating energy consumption, and use the force of high-frequency gas and water on the filter layer to make the filter materials rub and scrub each other, accelerate the destruction of the existing filter layer, and make the pollutants trapped and adsorbed on the surface of the filter material discharged from the filter bed.

[0020] The multi-microporous high-precision filtration device for treating oilfield oily wastewater of the present invention is combined with other equipment in the oily wastewater treatment process to treat wastewater, such as Figure 6 As shown, the steps are as follows: (1) After the oily wastewater is injected into the homogenization buffer tank for homogenization, it is injected into the high-efficiency viscosity reduction device, and demulsifier is added into the high-efficiency viscosity reduction device according to the indicators of the oily wastewater to oxidize and decompose the oily wastewater to reduce the viscosity of the raw water; (2) Injecting the oily wastewater after viscosity reduction into the water quality stabilization device, and at the same time, adding flocculants into the water quality stabilization device to remove the surface floating oil and part of the emulsified oil in the oily wastewater, and then recovering the surface floating oil, part of the emulsified oil, and bottom mud in the water quality stabilization device into the recovery pool; (3) The sewage treated by the water quality stabilization device is lifted to the multi-microporous high-precision filtration device through the intermediate water tank, and the multi-microporous ceramic filter layer in the device is used to adsorb and remove oil and suspended matter in the sewage; (4) The sewage treated by the multi-microporous high-precision filtration device enters the nano-scale filtration device through the buffer water tank for filtration, and then is injected into the clean water tank for storage; (5) The water stored in the clean water tank can be used as backwash water for the nano-filtration device and chemical washing water for the nano-filtration device. The water after backwashing and chemical washing will eventually be recycled into the high-efficiency viscosity reduction device; (6) The buffer water tank backwashes the multi-microporous high-precision filtration device; (7) The air washing system provides air source for the multi-microporous high-precision filtration device and the nano-scale filtration device.

[0021] In the above process, the effluent from the two-stage sedimentation tanks in the oily wastewater treatment station enters the high-efficiency viscosity reduction section for oxidation and decomposition treatment to reduce the viscosity of the raw water, thereby reducing the burden of subsequent process treatment; the effluent from the high-efficiency viscosity reduction section flows by gravity to the water quality stabilization section, and after entering the water quality stabilization section, the surface floating oil and part of the emulsified oil in the oily wastewater are removed; the effluent from the water quality stabilization section is lifted to the multi-microporous high-precision filtration section through the buffer intermediate water tank, and the oil and suspended matter in the oily wastewater are removed. The effluent water quality reaches the "double 10" index for oil and suspended matter, so as to meet the water inlet requirements of the subsequent nano-filtration section. The effluent from the nano-filtration section can meet the "5, 5, 2" index required for deep treatment of oily wastewater.

Claims

1. A multi-microporous high-precision filtration device for treating oilfield oily wastewater, comprising a tank body (1), wherein the lower end cap of the tank body (1) is seated on a support cylinder (2), and an inlet pipe (7) and an outlet pipe (8) are respectively provided on the upper end cap and the lower end cap, wherein: A high-strength supporting orifice plate (3) is fixed to the lower part of the tank body (1), a large-flux sand-blocking screen plate (4) is fixed on the high-strength supporting orifice plate (3), and a multi-porous ceramic filter material layer (5) is laid on the large-flux sand-blocking screen plate (4); an anti-blocking water distributor (6) is provided in the upper head and corresponds to the water inlet pipe (7); one end of the water outlet pipe (8) passes through the bottom of the tank body (1), is placed below the high-strength supporting orifice plate (3), and is surrounded by the outer wall thereof. A plurality of water distribution branch pipes (9) are evenly arranged around the tank body (1), and a plurality of through holes I (10) are arranged on the water distribution branch pipes (9); a multi-layer high-frequency gas scrubbing device (11) is arranged in the microporous ceramic filter material layer (5); the anti-blocking water distributor (6) is composed of a sand blocking screen cylinder (12) and a sand guiding and blocking screen cap (13); the upper end of the sand blocking screen cylinder (12) is fixed to the inner wall of the top end of the tank body (1), and the lower end is fixed to the sand guiding and blocking screen cap (13) through a flange.

2. A multi-microporous high-precision filtration device for treating oilfield oily wastewater according to claim 1, characterized in that The sand blocking screen cylinder (12) is composed of an annular sand blocking screen mesh I (20) fixed integrally therewith and wrapped around the outer circumference of a high-strength water distribution liner pipe (14), and a plurality of through holes II (15) are evenly distributed on the high-strength water distribution liner pipe (14).

3. The multi-microporous high-precision filtration device for treating oilfield oily wastewater according to claim 1 is characterized in that The sand-guiding and sand-blocking screen cap (13) is composed of an inner high-strength water-distributing lining cap (22) and an outer covered sand-blocking screen II (21) fixed together as one body, and the high-strength water-distributing lining cap (22) is evenly provided with a plurality of through holes II (23).

4. The multi-microporous high-precision filtration device for treating oilfield oily wastewater according to claim 3 is characterized in that The sand-guiding and sand-blocking screen cap (13) is an inverted truncated cone-shaped structure, the upper end opening of which is fixed to and communicated with the sand-blocking screen cylinder (12), and the lower end is blocked by a blocking plate (24).

5. A multi-microporous high-precision filtration device for treating oilfield oily wastewater according to claim 1, 2, 3 or 4, characterized in that The laying thickness of the microporous ceramic filter material layer (5) is 2.5 to 3 meters.

6. A multi-microporous high-precision filtration device for treating oilfield oily wastewater according to claim 1, 2, 3 or 4, characterized in that The multi-layer high-frequency gas scrubbing device (11) comprises an air distribution main pipe (16) and an air distribution branch pipe (17), one end of the air distribution main pipe (16) respectively passes through a high-strength supporting orifice plate (3) and a large-flux sand-blocking screen plate (4) and is placed in a multi-porous ceramic filter material layer (5), one or more layers of air distribution branch pipes (17) are arranged around the outer wall of the air distribution main pipe (16), one or more through holes III are arranged on the air distribution branch pipes (17), and a sand-blocking air distribution cap (18) is arranged on the through hole III, and the air inlet end of the air distribution main pipe (16) is placed outside the tank body (1).

7. A multi-microporous high-precision filtration device for treating oilfield oily wastewater according to claim 1, 2, 3 or 4, characterized in that A through hole IV (19) is provided on the outer wall of the support tube (2), and one end of the water outlet pipe (8) and the air distribution main pipe (16) passes through the through hole IV (19) and is placed outside the support tube (2).

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