Multistage filtration and purification device and method for oilfield reinjection water

Abstract

The invention discloses a multistage filtration and purification device and method for oilfield reinjection water, and belongs to the technical field of water treatment equipment.The multistage filtration and purification device for oilfield reinjection water comprises a barrel, an ultraviolet lamp, a cleaning mechanism, a liquid disturbing mechanism, a pretreatment mechanism, a first filtration mechanism and a second filtration mechanism. According to the multistage filtration and purification device for the oilfield reinjection water, the titanium dioxide photocatalyst catalysis plate, the quartz glass cover and the ultraviolet lamp are arranged, a photocatalyst is irradiated by ultraviolet rays to generate strong oxidizing free radicals, and the free radicals can decompose organic pollutants in the oilfield water into harmless carbon dioxide and water; the beneficial effects of efficiently purifying water quality and removing organic pollutants are achieved, so that the quality of reinjection water is improved, and the pollution to the environment is reduced; and through cooperation with the pretreatment mechanism, the first filtering mechanism and the second filtering mechanism, complex component pollutants in the oil field water can be effectively removed.

Description

Technical Field

[0001] This invention belongs to the technical field of water treatment equipment, and particularly relates to a multi-stage filtration and purification device and method for oilfield reinjection water. Background Technology

[0002] In the oil extraction industry, oilfield reinjection water is a crucial link in water resource recycling, and its treatment quality directly affects the sustainable extraction efficiency and environmental protection of oilfields. In recent years, with the continuous advancement of oil extraction technology and increasingly stringent environmental protection requirements, oilfield reinjection water treatment technology has also made significant progress.

[0003] Oilfield wastewater contains not only suspended oil droplets and solid particles, but also dissolved organic matter. Existing filtration devices have limited ability to remove pollutants with complex compositions. For example, commonly used sand filters and walnut shell filters can retain some larger suspended particles and some oil droplets, but they are not effective at removing tiny oil droplets and dissolved organic matter. Moreover, existing filtration devices have significant shortcomings in self-cleaning. During the filtration process, pollutants tend to accumulate on the surface and in the pores of the filter media, leading to increased filtration resistance, decreased flow rate, and frequent manual cleaning. Summary of the Invention

[0004] The purpose of this invention is to provide a multi-stage filtration and purification device and method for oilfield reinjection water, which solves the technical problems of existing filtration devices having limited ability to remove complex pollutants and significant deficiencies in self-cleaning, requiring frequent manual cleaning.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A multi-stage filtration and purification device for oilfield reinjection water includes: a cylindrical body with multiple titanium dioxide photocatalytic plates installed on its inner wall and a quartz glass cover installed on its inner bottom surface; an ultraviolet lamp installed inside the quartz glass cover; a cleaning mechanism for cleaning the titanium dioxide photocatalytic plates and the quartz glass cover; a liquid turbulence mechanism for drawing in outside air and delivering it to the bottom of the cylindrical body; a pretreatment mechanism for filtering the oilfield water entering the cylindrical body; a first filtration mechanism for filtering the water discharged from the cylindrical body; and a second filtration mechanism for filtering the water discharged from the first filtration mechanism.

[0006] Preferably, the cleaning mechanism includes: a scraper ring sleeved on the quartz glass cover; a cleaning brush connected to the scraper ring via multiple crossbars and in contact with multiple titanium dioxide photocatalyst plates; a multi-stage hydraulic cylinder mounted on the bottom surface of the cylinder body; and a connecting plate mounted on the extension end of the multi-stage hydraulic cylinder, with its other end connected to the crossbars.

[0007] Preferably, the liquid disturbance mechanism includes: a hollow ring installed on the inner bottom surface of the cylinder, with several through holes through its top surface; a piston cylinder installed on the inner bottom surface of the cylinder, having a gas supply pipe and a gas extraction pipe, the gas supply pipe being fixedly connected to and communicating with the hollow ring, and the gas extraction pipe extending to the outside of the cylinder; a piston plate slidably connected inside the piston cylinder, with multiple piston rods installed on the piston plate; a push plate connected to the upper ends of the multiple piston rods; multiple springs, all installed on the top surface of the push plate; and a cross plate fixedly connected to the crossbar, with its bottom surface connected to the multiple springs.

[0008] Preferably, the pretreatment mechanism includes: a cylinder connected to the cylinder body via two fixing plates, one end of which is open and a plurality of filter holes are provided through the lower part; a feed hopper installed on the cylinder; a slag discharge pipe installed on the feed hopper; a mounting base installed on the cylinder; a motor installed on the mounting base, with a shaft mounted on its power output shaft, the shaft being rotatably connected to the cylinder; a spiral blade located inside the cylinder and installed on the shaft; and a first pulley fixedly sleeved on the shaft.

[0009] Preferably, the first filtration mechanism includes: a filter box with an inlet pipe and a drain pipe installed on its two sides respectively, the other end of the inlet pipe being fixedly connected to and communicating with the cylinder; a filter plate installed inside the filter box; a discharge pipe installed on the bottom surface of the filter box, with a sealing cap installed at its lower end; and a solenoid valve installed on the inlet pipe.

[0010] Preferably, the second filtration mechanism includes: a spherical tube with a rotating ring rotatably mounted inside, wherein a polypropylene hollow fiber ultrafiltration membrane is installed inside the rotating ring; two horizontal tubes, both fixedly connected to and communicating with the spherical tube, both mounted on the bottom surface of the cylinder via hangers, one of the horizontal tubes being fixedly connected to and communicating with a drain pipe; a rotating ring rotatably connected to the spherical tube; a rotating shaft rotatably connected to the spherical tube, the upper end of which is fixedly connected to the rotating ring; and a disc mounted on the lower end of the rotating shaft, with two sets of teeth mounted on its side and two cylinders mounted on its bottom surface.

[0011] Preferably, the multi-stage filtration and purification device for oilfield reinjection water further includes a transmission mechanism, which includes: a reducer having an input shaft and an output shaft; a second pulley fixedly connected to the input shaft; a transmission belt sleeved on the second pulley and the first pulley; a transmission ring fixedly connected to the output shaft, with tooth grooves on its side that match the tooth set; and a actuating plate mounted on the transmission ring for pushing the cylinder.

[0012] Preferably, the multi-stage filtration and purification device for oilfield reinjection water further includes: multiple support legs, all installed on the bottom surface of the cylinder; a first mounting plate, installed on the support legs, for supporting the reducer; and a second mounting plate, installed on the support legs.

[0013] Preferably, the multi-stage filtration and purification device for oilfield reinjection water further includes: a proximity switch, mounted on the second mounting plate and facing the disc; and a controller, mounted on the second mounting plate and electrically connected to the proximity switch and the solenoid valve.

[0014] The operation method of the multi-stage filtration and purification device for oilfield reinjection water includes the following steps: Step 1: Inject oilfield water into the pretreatment mechanism cylinder through the feed hopper. Large particles are intercepted by the filter holes, and the filtrate falls into the cylinder. Step 2: Turn on the ultraviolet lamp and add coagulant into the cylinder. Then start the multi-stage hydraulic cylinder, which drives the crossbar to move up and down reciprocally via the connecting plate, thereby driving the scraper ring and cleaning brush to move down reciprocally to clean the titanium dioxide photocatalyst plate and quartz glass cover. When the multi-stage hydraulic cylinder is running, the liquid stirring mechanism will transport outside air into the hollow ring. The air forms bubbles through the hollow ring. When the bubbles rise and break, they will stir the water, promoting the photocatalytic free radical decomposition of organic matter and the reaction of coagulant and suspended solids; Step 3: After the treatment in the cylinder is completed, the solenoid valve is opened, and the water enters the filter box through the inlet pipe. The filter plate traps the coagulant; the filtrate enters the second filtration mechanism through the drain pipe. The polypropylene hollow fiber ultrafiltration membrane removes small molecule impurities and colloids, and finally the filtrate is discharged; Step 4: After the polypropylene hollow fiber ultrafiltration membrane has been working for a period of time, the motor is started to drive the transmission mechanism, which drives the polypropylene hollow fiber ultrafiltration membrane to rotate 180 degrees, switching the filtration surface of the polypropylene hollow fiber ultrafiltration membrane.

[0015] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. The multi-stage filtration and purification device for oilfield reinjection water in this invention uses a titanium dioxide photocatalytic plate, a quartz glass cover, and an ultraviolet lamp. By irradiating the photocatalyst with ultraviolet light, strong oxidizing free radicals are generated. These free radicals can decompose organic pollutants in oilfield water into harmless carbon dioxide and water, achieving the beneficial effects of highly efficient water purification and removal of organic pollutants, thereby improving the quality of reinjection water and reducing environmental pollution. Furthermore, by cooperating with the pretreatment unit, the first filtration unit, and the second filtration unit, it can effectively remove complex pollutants from oilfield water.

[0016] 2. The multi-stage filtration and purification device for oilfield reinjection water in this invention, by setting up a liquid stirring mechanism, adds coagulant into the cylinder and stirs it through the liquid stirring mechanism, which can remove suspended solids and colloidal substances in oilfield water through coagulant. At the same time, stirring can also improve the mixing efficiency of coagulant and water. Furthermore, stirring the water can also promote the contact between organic pollutants and photocatalysts, thereby improving mass transfer efficiency and further purifying water quality.

[0017] 3. The multi-stage filtration and purification device for oilfield reinjection water in this invention, by setting up a cleaning mechanism, can clean the quartz glass cover and titanium dioxide photocatalytic plate, improve the irradiation effect of ultraviolet light, ensure the continuous and efficient photocatalytic oxidation reaction, and the cleaning mechanism can also drive the liquid disturbance mechanism during operation, thereby improving the energy utilization rate.

[0018] 4. The multi-stage filtration and purification device for oilfield reinjection water in this invention, by setting up a second filtration mechanism and a transmission mechanism, allows the polypropylene hollow fiber ultrafiltration membrane in the second filtration mechanism to remove macromolecular substances, suspended solids, and some organic matter through sieving and adsorption, thereby further improving water quality. Furthermore, by rotating the rotating ring and the polypropylene hollow fiber ultrafiltration membrane, the clogged side can be removed from contact with the oilfield water, and then the impurities can be dislodged by gravity and water flow impact, slowing down the membrane clogging speed and extending the service life. Moreover, by setting up a transmission mechanism, the filter surface can be automatically switched, reducing manual intervention. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This invention provides a three-dimensional multi-stage filtration and purification device for oilfield reinjection water. Figure 1 ; Figure 2 This invention provides a three-dimensional multi-stage filtration and purification device for oilfield reinjection water. Figure 2 ; Figure 3 This is a schematic diagram of the assembly structure of the pretreatment mechanism, the first filtration mechanism, and the second filtration mechanism in this invention; Figure 4 This is a perspective view of the cylindrical body in this invention from a top view angle; Figure 5 This is a schematic diagram of the assembly structure of the titanium dioxide photocatalytic plate, quartz glass cover and piston cylinder in this invention; Figure 6 This is a schematic diagram of the assembly structure of the quartz glass cover, cleaning mechanism, and liquid disturbance mechanism in this invention. Figure 1 ; Figure 7 This is a schematic diagram of the assembly structure of the quartz glass cover, cleaning mechanism, and liquid disturbance mechanism in this invention. Figure 2 ; Figure 8 This is a schematic diagram of the internal structure of the filter box in this invention; Figure 9This is a schematic diagram of the assembly structure of the motor, shaft, helical blade, second filter mechanism, and transmission mechanism in this invention. Figure 10 This is a schematic diagram of the assembly structure of the rotating ring, polypropylene hollow fiber ultrafiltration membrane and transmission mechanism in this invention; Figure 11 In this invention Figure 10 Enlarged schematic diagram of part A; Reference numerals: 100, cylinder; 101, titanium dioxide photocatalyst plate; 102, quartz glass cover; 103, ultraviolet lamp; 104, support leg; 105, first mounting plate; 106, second mounting plate; 107, proximity switch; 108, controller; 110, cleaning mechanism; 111, scraper ring; 112, cleaning brush; 113, crossbar; 114, multi-stage hydraulic cylinder; 115, connecting plate; 120, liquid stirring mechanism; 121, hollow ring; 122, through hole; 123, piston cylinder; 124, gas supply pipe; 125, exhaust pipe; 126, piston rod; 127, push plate; 128, spring; 129, cross plate; 130, pretreatment mechanism; 131, cylinder; 1331, filter hole; 132, fixing plate; 133, feed hopper; 134, slag discharge pipe; 135. Mounting base; 136. Motor; 137. Shaft; 138. Spiral blade; 139. First pulley; 140. First filtration mechanism; 141. Filter box; 142. Inlet pipe; 143. Drain pipe; 144. Filter plate; 145. Discharge pipe; 146. Sealing cover; 147. Solenoid valve; 150. Second filtration mechanism; 151. Spherical tube; 152. Horizontal tube; 153. Hanger; 154. Rotating ring; 155. Polypropylene hollow fiber ultrafiltration membrane; 156. Rotating shaft; 157. Disc; 158. Tooth assembly; 159. Cylinder; 160. Transmission mechanism; 161. Reducer; 162. Input shaft; 163. Output shaft; 164. Second pulley; 165. Transmission belt; 166. Transmission ring; 167. Tooth groove; 168. Actuating plate. Detailed Implementation

[0021] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0022] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0023] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0024] This invention is described in detail with reference to the accompanying drawings. When detailing the embodiments of this invention, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged, not to scale. Furthermore, the accompanying drawings are merely examples and should not be construed as limiting the scope of protection of this invention. In actual fabrication, the three-dimensional spatial dimensions of length, width, and depth should be included.

[0025] Furthermore, it should be noted in the description of this invention that the terms "first," "second," or "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0026] Unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" in this invention should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; similarly, they can refer to mechanical connections, electrical connections, or direct connections, or indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0027] Example 1: As Figures 1-5 As shown, the multi-stage filtration and purification device for oilfield reinjection water includes a cylinder 100, an ultraviolet lamp 103, a cleaning mechanism 110, a liquid disturbance mechanism 120, a pretreatment mechanism 130, a first filtration mechanism 140, and a second filtration mechanism 150.

[0028] Multiple titanium dioxide photocatalyst plates 101 are installed on the inner wall of the cylinder 100. A quartz glass cover 102 is installed on the inner bottom surface of the cylinder 100. The quartz glass cover 102 is transparent. The transmittance of quartz glass to the UVC band (254nm) can reach more than 90%, which is much higher than that of ordinary glass.

[0029] An ultraviolet lamp 103 is installed inside a quartz glass cover 102; a cleaning mechanism 110 is used to clean the titanium dioxide photocatalyst plate 101 and the quartz glass cover 102; a liquid stirring mechanism 120 is used to draw in outside air and deliver the air to the bottom of the cylinder 100; a pretreatment mechanism 130 is used to filter the oilfield water entering the cylinder 100; a first filtration mechanism 140 is used to filter the water discharged from the cylinder 100; and a second filtration mechanism 150 is used to filter the water discharged from the first filtration mechanism 140.

[0030] The oilfield water mentioned in this article refers to oilfield wastewater.

[0031] Specifically, the oilfield water to be treated is added to the pretreatment unit 130, which performs preliminary filtration on the oilfield water. The pre-filtered oilfield water then enters the cylinder 100.

[0032] Then, by activating the ultraviolet lamp 103, the ultraviolet light emitted by the ultraviolet lamp 103 irradiates the titanium dioxide photocatalyst plate 101. Under the irradiation of ultraviolet light, the surface of the titanium dioxide photocatalyst releases electrons and holes. The electrons and holes react with the surrounding water molecules and oxygen to generate free radicals with strong oxidizing properties. The free radicals can attack the organic pollutants in the oily water and decompose them into harmless substances such as carbon dioxide and water.

[0033] Meanwhile, by adding a coagulant into the cylinder 100, the coagulant removes suspended solids and colloidal substances from the oilfield water, while reducing the obstruction of ultraviolet light by suspended solids and colloidal substances, thereby improving the irradiation effect of ultraviolet light on the titanium dioxide photocatalytic plate 101.

[0034] Then, the cleaning mechanism 110 is activated to clean the quartz glass cover 102 and the titanium dioxide photocatalytic plate 101, removing the debris attached to the quartz glass cover 102 and the titanium dioxide photocatalytic plate 101, thereby further improving the irradiation effect of ultraviolet light on the titanium dioxide photocatalytic plate 101.

[0035] Furthermore, when the cleaning mechanism 110 is running, the liquid stirring mechanism 120 will draw in outside air and deliver the air to the bottom of the cylinder 100. The air at the bottom of the cylinder 100 will form bubbles in the water. The rising and breaking of the bubbles will stir the oilfield water, allowing the organic pollutants in the oilfield water to be more evenly distributed on the surface of the photocatalyst, improving the mass transfer efficiency and thus enhancing the effect of photocatalytic oxidation. The stirring effect also helps to accelerate the rapid mixing of the coagulant and the water, making the coagulant more evenly dispersed in the water and increasing the contact opportunities with suspended solids and colloids.

[0036] After the oilfield water in the cylinder 100 is treated, the water is transported to the first filtration mechanism 140, where it is filtered to remove coagulants. The filtered water is then transported to the second filtration mechanism 150 for further filtration, thereby improving the treatment effect of the oilfield water.

[0037] like Figures 5-7 As shown, the cleaning mechanism 110 includes a scraper ring 111, a cleaning brush 112, a multi-stage hydraulic cylinder 114, and a connecting plate 115. The scraper ring 111 is fitted onto the quartz glass cover 102, and the inner wall of the scraper ring 111 contacts the quartz glass cover 102. The inner wall of the scraper ring 111 is made of rubber and will not scratch the quartz glass cover 102. The cleaning brush 112 is connected to the scraper ring 111 via multiple crossbars 113. The cleaning brush 112 contacts multiple titanium dioxide photocatalyst plates 101. The cleaning brush 112 is annular, and its outer surface is provided with bristles. The multi-stage hydraulic cylinder 114 is installed on the inner bottom surface of the cylinder 100. The multi-stage hydraulic cylinder 114 is waterproof. The connecting plate 115 is installed on the extension end of the multi-stage hydraulic cylinder 114, and the other end of the connecting plate 115 is connected to the crossbars 113.

[0038] Specifically, by activating the multi-stage hydraulic cylinder 114, the crossbar 113 is driven to move up and down repeatedly via the connecting plate 115, which in turn drives the scraper ring 111 and the cleaning brush 112 to move down repeatedly, thereby enabling the cleaning brush 112 to clean the titanium dioxide photocatalytic plate 101 and the scraper ring 111 to clean the quartz glass cover 102.

[0039] like Figures 5-7 As shown, the liquid disturbance mechanism 120 includes a hollow ring 121, a piston cylinder 123, a push plate 127, multiple springs 128, and a cross plate 129. The hollow ring 121 is installed on the inner bottom surface of the cylinder 100, and its top surface has several through holes 122. The piston cylinder 123 is installed on the inner bottom surface of the cylinder 100. The piston cylinder 123 has an air supply pipe 124 and an air extraction pipe 125. The air supply pipe 124 is fixedly connected to and communicates with the hollow ring 121, and the air extraction pipe 125 extends to the outside of the cylinder 100. A piston plate is slidably connected inside the piston cylinder 123, and multiple piston rods 126 are installed on the piston plate. The piston rods 126 are slidably connected to the piston cylinder 123. One-way valves are installed in both the air supply pipe 124 and the air extraction pipe 125, so that outside air can only enter the piston cylinder 123 in one direction through the air extraction pipe 125, and the air in the piston cylinder 123 can only enter the hollow ring 121 in one direction through the air supply pipe 124. The push plate 127 is connected to the upper end of multiple piston rods 126; multiple springs 128 are installed on the top surface of the push plate 127; the horizontal plate 129 is fixedly connected to the horizontal rod 113, and the bottom surface of the horizontal plate 129 is connected to multiple springs 128.

[0040] Specifically, when the crossbar 113 moves upward, it will drive the push plate 127 to move upward via the cross plate 129 and multiple springs 128, which in turn will drive the piston rod 126 and piston plate to move upward, thereby allowing outside air to be drawn into the piston cylinder 123 through the air extraction pipe 125.

[0041] When the crossbar 113 moves downward, it will drive the push plate 127 to move downward via the cross plate 129 and multiple springs 128, which in turn will drive the piston rod 126 and piston plate to move downward, thereby allowing the air in the piston cylinder 123 to be transported to the hollow ring 121 through the air supply pipe 124.

[0042] By repeatedly moving the horizontal bar 113 up and down, outside air can be continuously transported into the hollow ring 121, and then the air can be discharged through several through holes 122.

[0043] like Figures 1-3 and Figure 9 As shown, the pretreatment mechanism 130 includes a cylinder 131, a feed hopper 133, a slag discharge pipe 134, a mounting base 135, a motor 136, a spiral blade 138, and a first pulley 139. The cylinder 131 is connected to the cylinder body 100 through two fixing plates 132. One end of the cylinder 131 is open, and a plurality of filter holes 1331 are provided through the lower part of the cylinder 131. The plurality of filter holes 1331 are all located directly above the cylinder body 100. A feed hopper 133 is mounted on a cylinder 131; a slag discharge pipe 134 is mounted on a feed hopper 133; a mounting base 135 is mounted on a cylinder 131; a motor 136 is mounted on a mounting base 135, and a shaft 137 is mounted on the power output shaft 163 of the motor 136, which is rotatably connected to the cylinder 131; a spiral blade 138 is located inside the cylinder 131, and is mounted on the shaft 137, contacting the inner wall of the cylinder 131; a first pulley 139 is fixedly sleeved on the shaft 137.

[0044] Specifically, the oilfield water to be treated is fed into the cylinder 131 through the feed hopper 133. Several filter holes 1331 on the cylinder 131 will filter the oilfield water, leaving large particles in the oilfield water inside the cylinder 131. The filtered oilfield water will fall into the cylinder body 100.

[0045] Then, by starting the motor 136, the motor 136 drives the shaft 137 to rotate, which in turn drives the spiral blade 138 to rotate. The rotating spiral blade 138 will push the large particles in the cylinder 131 to move, so that the large particles gradually move towards the discharge pipe 145, and then the large particles in the cylinder 131 are discharged through the discharge pipe 145.

[0046] like Figure 8As shown, the first filtration mechanism 140 includes a filter box 141, a filter plate 144, a discharge pipe 145, and a solenoid valve 147. An inlet pipe 142 and a discharge pipe 143 are respectively installed on both sides of the filter box 141. The other end of the inlet pipe 142 is fixedly connected to and communicates with the cylinder 100. The filter plate 144 is installed inside the filter box 141. The discharge pipe 145 is installed on the bottom surface of the filter box 141, and a sealing cap 146 is threadedly connected to the lower end of the discharge pipe 145. The solenoid valve 147 is installed on the inlet pipe 142.

[0047] Specifically, when the solenoid valve 147 is opened, the water and coagulant in the cylinder 100 enter the filter box 141 through the inlet pipe 142. The water is filtered by the filter plate 144, while the coagulant remains in the filter box 141. When it is necessary to discharge the coagulant, the coagulant in the filter box 141 is discharged through the discharge pipe 145 by opening the sealing cover 146.

[0048] Working principle: In practical use, the oilfield water to be treated is fed into the cylinder 131 through the feed hopper 133. Several filter holes 1331 on the cylinder 131 filter the oilfield water, leaving large particles in the oilfield water inside the cylinder 131. The filtered oilfield water falls into the cylinder body 100. Then, by starting the motor 136, the motor 136 drives the shaft 137 to rotate, which in turn drives the spiral blades 138 to rotate. The rotating spiral blades 138 push the large particles in the cylinder 131 to move, causing the large particles to gradually move towards the discharge pipe 145, and then the large particles in the cylinder 131 are discharged through the discharge pipe 145.

[0049] Then, by activating the ultraviolet lamp 103, the ultraviolet light emitted by the ultraviolet lamp 103 irradiates the titanium dioxide photocatalyst plate 101. Under the irradiation of ultraviolet light, the surface of the titanium dioxide photocatalyst releases electrons and holes. The electrons and holes react with the surrounding water molecules and oxygen to generate free radicals with strong oxidizing properties. The free radicals can attack the organic pollutants in the oily water and decompose them into harmless substances such as carbon dioxide and water.

[0050] Meanwhile, by adding a coagulant into the cylinder 100, the coagulant removes suspended solids and colloidal substances from the oilfield water, reducing the obstruction of ultraviolet light by suspended solids and colloidal substances, and improving the irradiation effect of ultraviolet light on the titanium dioxide photocatalytic plate 101.

[0051] Then, the multi-stage hydraulic cylinder 114 is activated, which drives the crossbar 113 to move up and down repeatedly via the connecting plate 115, thereby driving the scraper ring 111 and the cleaning brush 112 to move down repeatedly, so that the cleaning brush 112 cleans the titanium dioxide photocatalytic plate 101 and the scraper ring 111 cleans the quartz glass cover 102.

[0052] When the crossbar 113 moves upward, it drives the push plate 127 upward via the cross plate 129 and multiple springs 128, which in turn drives the piston rod 126 and piston plate upward, thereby drawing outside air into the piston cylinder 123 through the suction pipe 125. When the crossbar 113 moves downward, it drives the push plate 127 downward via the cross plate 129 and multiple springs 128, which in turn drives the piston rod 126 and piston plate downward, thereby delivering the air in the piston cylinder 123 to the hollow ring 121 through the air supply pipe 124.

[0053] By repeatedly moving the horizontal bar 113 up and down, outside air can be continuously transported into the hollow ring 121, and then the air is discharged through several through holes 122. The discharged air will form bubbles in the water. The rising and breaking of the bubbles will stir the oilfield water, so that the organic pollutants in the oilfield water can be more evenly distributed on the surface of the photocatalyst, improving the mass transfer efficiency and thus enhancing the effect of photocatalytic oxidation. The stirring effect also helps to accelerate the rapid mixing of coagulant and water, so that the coagulant is more evenly dispersed in the water, increasing the contact opportunities with suspended solids and colloids.

[0054] After the oilfield water in the cylinder 100 is treated, the solenoid valve 147 is opened, allowing the water and coagulants in the cylinder 100 to enter the filter box 141 through the inlet pipe 142. The water is filtered by the filter plate 144, leaving the coagulants in the filter box 141. The water filtered by the filter plate 144 is then transported to the second filtration mechanism 150, where it is filtered again to further improve the treatment effect of the oilfield water.

[0055] Example 2: Figures 9-11 As shown, while all other parts are the same as in Example 1, the difference between this example and Example 1 is that: The second filtration mechanism 150 includes a spherical tube 151, two horizontal tubes 152, a rotating ring 154, a rotating shaft 156, and a disc 157. A rotating ring 154 is rotatably installed inside the spherical tube 151, and a polypropylene hollow fiber ultrafiltration membrane 155 is installed inside the rotating ring 154; two horizontal tubes 152 are fixedly connected to and communicate with the spherical tube 151, and both horizontal tubes 152 are installed on the bottom surface of the cylinder 100 through hangers 153, one of the horizontal tubes 152 is fixedly connected to and communicates with the drain pipe 143; the rotating ring 154 is rotatably connected to the spherical tube 151; the rotating shaft 156 is rotatably connected to the spherical tube 151, and the upper end of the rotating shaft 156 is fixedly connected to the rotating ring 154; a disc 157 is installed at the lower end of the rotating shaft 156, two sets of toothed assemblies 158 are installed on the side of the disc 157, and two cylinders 159 are installed on the bottom surface of the disc 157. The disc 157, the toothed assemblies 158, and the cylinders 159 are all made of metal.

[0056] Specifically, the water discharged through the drain pipe 143 enters the spherical tube 151. The polypropylene hollow fiber ultrafiltration membrane 155 inside the spherical tube 151 further filters the water. Large molecules, suspended solids, colloids, and other impurities in the water, being larger than the membrane pore size, are trapped on the surface of the polypropylene hollow fiber ultrafiltration membrane 155, while water molecules and small molecules can pass through the membrane pores, thus achieving solid-liquid separation. This effectively removes most impurities from the oilfield water, improving water quality. Furthermore, in addition to its sieving function, the polypropylene hollow fiber ultrafiltration membrane 155 also has a certain adsorption capacity, capable of adsorbing some organic matter and heavy metal ions in the water, further enhancing the filtration effect.

[0057] Furthermore, after the polypropylene hollow fiber ultrafiltration membrane 155 has been used for a period of time, when one side of the membrane becomes clogged, causing a decrease in filtration efficiency, rotating the shaft 156 by 180 degrees will cause the rotating ring 154 and the polypropylene hollow fiber ultrafiltration membrane 155 to rotate, temporarily removing the clogged side from contact with wastewater, while the other side continues filtration. At this time, some of the debris on the clogged side will be dislodged under gravity or water flow impact, restoring some permeability. By rotating the rotating ring 154 and the polypropylene hollow fiber ultrafiltration membrane 155, the clogging rate of the membrane can be slowed down, thereby reducing the frequency of cleaning the membrane.

[0058] By regularly backwashing the polypropylene hollow fiber ultrafiltration membrane 155, the polypropylene hollow fiber ultrafiltration membrane 155 can maintain a good filtration effect.

[0059] like Figures 9-11 As shown, the multi-stage filtration and purification device for oilfield reinjection water also includes a transmission mechanism 160. The transmission mechanism 160 includes a reducer 161, a second pulley 164, a transmission belt 165, a transmission ring 166, and a deflector plate 168. The reducer 161 has an input shaft 162 and an output shaft 163; the second pulley 164 is fixedly connected to the input shaft 162; the transmission belt 165 is sleeved on the second pulley 164 and the first pulley 139; the transmission ring 166 is fixedly connected to the output shaft 163, and the side of the transmission ring 166 has a tooth groove 167 that matches the tooth set 158; the deflector plate 168 is installed on the transmission ring 166 and is used to push the cylinder 159.

[0060] Specifically, when the motor 136 is running, it drives the shaft 137 to rotate, which in turn drives the input shaft 162 of the reducer 161 to rotate via the first pulley 139, the transmission belt 165, and the second pulley 164. This causes the output shaft 163 of the reducer 161 to drive the rotating ring 154 to rotate. When the rotating ring 154 rotates, the actuating plate 168 pushes the cylinder 159 to move, and the toothed groove 167 drives the disc 157 to rotate via the toothed set 158.

[0061] It should be noted that when the rotating ring 154 rotates one revolution, it will drive the disc 157 to rotate 180 degrees through the tooth groove 167 and the tooth assembly 158.

[0062] like Figure 1 , Figure 2 and Figure 9 As shown, the multi-stage filtration and purification device for oilfield reinjection water also includes multiple support legs 104, a first mounting plate 105, a second mounting plate 106, a proximity switch 107, and a controller 108. The support legs 104 are all mounted on the bottom surface of the cylinder 100. The first mounting plate 105 is mounted on the support legs 104 to support the reducer 161. The second mounting plate 106 is mounted on the support legs 104. The proximity switch 107 is mounted on the second mounting plate 106, facing the disc 157. The controller 108 is mounted on the second mounting plate 106 and is electrically connected to the proximity switch 107 and the solenoid valve 147.

[0063] Specifically, when the disc 157 rotates, the tooth assembly 158, the rotating shaft 156, and the rotating ring 154 will rotate along with the disc 157. The proximity switch 107 can determine whether the disc 157 and the rotating shaft 156 are rotating by detecting the proximity state of the tooth assembly 158. When the tooth assembly 158 is detected to be approaching or moving away from the proximity switch 107, that is, when the disc 157 and the tooth assembly 158 are rotating, the proximity switch 107 will generate a switching signal and close the solenoid valve 147 through the controller 108.

[0064] Working principle: When water needs to be discharged from the cylinder 100, the solenoid valve 147 and motor 136 are opened, allowing the water in the cylinder 100 to enter the first filtration mechanism 140. After filtration by the first filtration mechanism 140, the water is transported to the spherical tube 151. Inside the spherical tube 151, the polypropylene hollow fiber ultrafiltration membrane 155 further filters the water. Large molecules, suspended solids, colloids, and other impurities in the water, because their size is larger than the membrane pore size, are trapped on the surface of the polypropylene hollow fiber ultrafiltration membrane 155, while water molecules and small molecules can pass through the membrane pores, thereby achieving solid-liquid separation. This effectively removes most of the impurities in the oilfield water and improves water quality. In addition to its sieving function, the polypropylene hollow fiber ultrafiltration membrane 155 also has a certain adsorption capacity, which can adsorb some organic matter and heavy metal ions in the water, further improving the filtration effect.

[0065] When the motor 136 runs, it drives the shaft 137 to rotate, which in turn drives the input shaft 162 of the reducer 161 to rotate via the first pulley 139, the transmission belt 165, and the second pulley 164. This, in turn, causes the output shaft 163 of the reducer 161 to drive the rotating ring 154 to rotate. When the rotating ring 154 rotates, the actuating plate 168 pushes the cylinder 159 to move, and the toothed groove 167 drives the disc 157 to rotate via the toothed assembly 158. When the rotating ring 154 rotates one revolution, it drives the disc 157 to rotate 180 degrees via the toothed groove 167 and the toothed assembly 158. This, in turn, drives the rotating shaft 156 and the rotating ring 154 to rotate 180 degrees, which in turn drives the polypropylene hollow fiber ultrafiltration membrane 155 to rotate 180 degrees. This temporarily removes the blocked side from contact with the sewage, while the other side continues to filter. At this time, some of the debris on the blocked side will fall off under the impact of gravity or water flow, restoring some permeability. By rotating the rotating ring 154 and the polypropylene hollow fiber ultrafiltration membrane 155, the clogging rate of the polypropylene hollow fiber ultrafiltration membrane 155 can be slowed down, thereby reducing the frequency of cleaning the polypropylene hollow fiber ultrafiltration membrane 155.

[0066] Furthermore, due to the presence of proximity switch 107 and controller 108, when disk 157 rotates, tooth assembly 158, rotating shaft 156, and rotating ring 154 will rotate along with disk 157. Proximity switch 107 can determine whether disk 157 and rotating shaft 156 are rotating by detecting the proximity state of tooth assembly 158. When tooth assembly 158 is detected approaching or moving away from proximity switch 107, i.e., when disk 157 and tooth assembly 158 are rotating, proximity switch 107 will generate a switching signal and close solenoid valve 147 through controller 108. This prevents water from flowing through spherical tube 151 when rotating ring 154 and polypropylene hollow fiber ultrafiltration membrane 155 are rotating, ensuring the filtration effectiveness of polypropylene hollow fiber ultrafiltration membrane 155.

[0067] Example 3: As Figures 1-11 As shown, the method of using the multi-stage filtration and purification device for oilfield reinjection water includes the following steps: Step 1: Oilfield water is injected into the pretreatment mechanism 130 cylinder 131 through the feed hopper 133. Large particles are intercepted by the filter holes 1331, and the filtrate falls into the cylinder 100. By starting the motor 136, the spiral blades 138 are driven to rotate, so that the spiral blades 138 push the large particles to the slag discharge pipe 134 for discharge. Step 2: Turn on the ultraviolet lamp 103 and add coagulant into the cylinder 100 at the same time; then start the multi-stage hydraulic cylinder 114, which drives the crossbar 113 to move up and down repeatedly through the connecting plate 115, thereby driving the scraper ring 111 and the cleaning brush 112 to move down repeatedly, so that the cleaning brush 112 cleans the titanium dioxide photocatalytic plate 101 and the scraper ring 111 cleans the quartz glass cover 102. Furthermore, when the multi-stage hydraulic cylinder 114 is in operation, it will transport outside air into the hollow ring 121 through the cooperation of the crossbar 113, cross plate 129, spring 128, push plate 127, piston cylinder 123, piston plate, piston rod 126, air supply pipe 124 and air extraction pipe 125. Then, the air will be discharged through several through holes 122. The discharged air will form bubbles in the water. The rising and breaking process of the bubbles will stir the oilfield water, so that the organic pollutants in the oilfield water can be more evenly distributed on the surface of the photocatalyst, improving the mass transfer efficiency and thus enhancing the effect of photocatalytic oxidation. The stirring effect also helps to accelerate the rapid mixing of coagulant and water, so that the coagulant is more evenly dispersed in the water, increasing the contact opportunities with suspended solids and colloids. Among them, polyaluminum chloride was selected as the coagulant, with a dosage of 70 mg / L; Step 3: After the treatment in the cylinder 100 is completed, open the solenoid valve 147. The water enters the filter box 141 through the inlet pipe 142. The filter plate 144 intercepts the coagulants. The filtrate enters the second filtration mechanism 150 through the drain pipe 143. The polypropylene hollow fiber ultrafiltration membrane 155 removes small molecule impurities and colloids. Finally, the filtrate is discharged. Step 4: After the polypropylene hollow fiber ultrafiltration membrane 155 has been working for a period of time, such as a cumulative working time of 8 hours, the motor 136 is started, which drives the shaft 137 to rotate. This, in turn, drives the input shaft 162 of the reducer 161 to rotate via the first pulley 139, the transmission belt 165, and the second pulley 164. This, in turn, drives the output shaft 163 of the reducer 161 to rotate the rotating ring 154. When the rotating ring 154 rotates, the actuating plate 168 pushes the cylinder 159 to move. The toothed groove 167 drives the disc 157 to rotate via the toothed tooth assembly 158. When the rotating ring 154 rotates one revolution, it drives the disc 157 to rotate 180 degrees via the toothed groove 167 and the toothed tooth assembly 158. This drives the rotating shaft 156 and the rotating ring 154 to rotate 180 degrees, which in turn drives the polypropylene hollow fiber ultrafiltration membrane 155 to rotate 180 degrees, thus switching the filtration surface of the polypropylene hollow fiber ultrafiltration membrane 155.

[0068] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

[0069] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A multi-stage filtration and purification device for oilfield reinjection water, characterized in that, include: The cylinder has multiple titanium dioxide photocatalytic plates installed on its inner wall, and a quartz glass cover installed on its inner bottom surface. An ultraviolet lamp is installed inside the quartz glass cover; A cleaning mechanism is used to clean the titanium dioxide photocatalyst catalytic plate and the quartz glass cover; The liquid-dispersing mechanism is used to draw in outside air and deliver it to the bottom of the cylinder. A pretreatment unit is used to filter the oilfield water entering the cylinder; The first filtration mechanism is used to filter the water discharged from the cylinder; The second filtration unit is used to filter the water discharged from the first filtration unit.

2. The multi-stage filtration and purification device for oilfield reinjection water according to claim 1, characterized in that, The cleaning facility includes: A scraper ring is fitted onto the quartz glass cover; The cleaning brush is connected to the scraper ring via multiple crossbars and contacts multiple titanium dioxide photocatalytic plates. A multi-stage hydraulic cylinder is installed on the bottom surface of the inner cylinder; A connecting plate is mounted on the extension end of the multi-stage hydraulic cylinder, and its other end is connected to the crossbar.

3. The multi-stage filtration and purification device for oilfield reinjection water according to claim 2, characterized in that, The liquid disturbance mechanism includes: A hollow ring is installed on the inner bottom surface of the cylinder, and its top surface has several through holes; A piston cylinder is installed on the bottom surface of the cylinder body. It has an air supply pipe and an air extraction pipe. The air supply pipe is fixedly connected to and communicates with a hollow ring. The air extraction pipe extends to the outside of the cylinder body. A piston plate is slidably connected inside the piston cylinder. Multiple piston rods are installed on the piston plate. A push plate is connected to the upper ends of the plurality of piston rods; Multiple springs are mounted on the top surface of the push plate; A horizontal plate is fixedly connected to the horizontal bar, and its bottom surface is connected to a plurality of springs.

4. The multi-stage filtration and purification device for oilfield reinjection water according to claim 1, characterized in that, The pretreatment mechanism includes: A cylindrical tube is connected to the cylindrical body by two fixing plates. One end of the tube is open, and several filter holes are opened through the lower part. The feed hopper is installed on the cylinder; The slag discharge pipe is installed on the feed hopper; Mounting base, mounted on the cylinder; The motor is mounted on the mounting base, and a shaft is mounted on its power output shaft, the shaft being rotatably connected to the cylinder. The spiral blades are located inside the cylinder and mounted on the shaft. The first pulley is fixedly sleeved on the shaft.

5. The multi-stage filtration and purification device for oilfield reinjection water according to claim 4, characterized in that, The first filtration mechanism includes: A filter box, with an inlet pipe and a outlet pipe installed on its two sides respectively, the other end of the inlet pipe being fixedly connected to and communicating with the cylinder body; The filter plate is installed inside the filter box; The discharge pipe is installed on the bottom surface of the filter box, and a sealing cover is installed at its lower end; A solenoid valve is installed on the inlet pipe.

6. The multi-stage filtration and purification device for oilfield reinjection water according to claim 5, characterized in that, The second filtration mechanism includes: A spherical tube with a rotating ring installed inside, and a polypropylene hollow fiber ultrafiltration membrane installed inside the rotating ring; Two horizontal pipes are both fixedly connected to and connected to the spherical pipe, and both are installed on the bottom surface of the cylinder by a hanger. One of the horizontal pipes is fixedly connected to and connected to the drain pipe. A rotating ring is rotatably connected to the spherical tube; A rotating shaft is rotatably connected to the spherical tube, and its upper end is fixedly connected to the rotating ring. A disc is installed at the lower end of the rotating shaft, with two sets of teeth mounted on its side and two cylinders mounted on its bottom surface.

7. The multi-stage filtration and purification device for oilfield reinjection water according to claim 6, characterized in that, It also includes a transmission mechanism, which comprises: A speed reducer, which has an input shaft and an output shaft; The second pulley is fixedly connected to the input shaft; A drive belt is fitted onto the second pulley and the first pulley; The transmission ring is fixedly connected to the output shaft, and its side surface has a tooth groove that matches the tooth assembly; A toggle plate, mounted on the transmission ring, is used to push the cylinder.

8. The multi-stage filtration and purification device for oilfield reinjection water according to claim 7, characterized in that, Also includes: Multiple support legs are installed on the bottom surface of the cylinder; The first mounting plate is mounted on the support leg to support the reducer; The second mounting plate is mounted on the support leg.

9. The multi-stage filtration and purification device for oilfield reinjection water according to claim 8, characterized in that, Also includes: A proximity switch is mounted on the second mounting plate, facing the disk; The controller is mounted on the second mounting plate and is electrically connected to the proximity switch and the solenoid valve.

10. The method of using a multi-stage filtration and purification device for oilfield reinjection water, characterized in that, Includes the following steps: Step 1: Oilfield water is injected into the pretreatment mechanism cylinder through the feed hopper. Large particles are intercepted by the filter holes, and the filtrate falls into the cylinder. Step 2: Turn on the ultraviolet lamp and add coagulant into the cylinder; then start the multi-stage hydraulic cylinder, which drives the crossbar to move up and down repeatedly via the connecting plate, thereby driving the scraper ring and cleaning brush to move down repeatedly to clean the titanium dioxide photocatalytic plate and quartz glass cover; when the multi-stage hydraulic cylinder is running, the liquid stirring mechanism will deliver outside air into the hollow ring, and the air will form bubbles through the hollow ring. When the bubbles rise and break, they will stir the water, promoting the photocatalytic free radical decomposition of organic matter and the reaction between coagulant and suspended solids; Step 3: After the treatment inside the cylinder is completed, open the solenoid valve. The water enters the filter box through the inlet pipe, and the filter plate traps the coagulants. The filtrate enters the second filtration mechanism through the drain pipe. The polypropylene hollow fiber ultrafiltration membrane removes small molecule impurities and colloids, and finally the filtrate is discharged. Step 4: After the polypropylene hollow fiber ultrafiltration membrane has been working for a period of time, start the motor to drive the transmission mechanism and rotate the polypropylene hollow fiber ultrafiltration membrane 180 degrees to switch the filtration surface of the polypropylene hollow fiber ultrafiltration membrane.

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