An external floating roof oil tank sewage oil-water separation system

Abstract

The present invention relates to an external floating roof oil tank sewage oil-water separation system in the field of petrochemical emission treatment technology, comprising an oil storage tank, a cyclone separator and a gravity separation tank; the gravity separation tank is divided into a floating tank and an overflow tank, the walls of the floating tank and the overflow tank are respectively provided with a first oil discharge pipe and a first drainage pipe, and the floating tank is equipped with a first liquid level gauge; the lower port of the cyclone separator is connected with a discharge pipe extending into the floating tank, the upper port of the cyclone separator is provided with an overflow notch, an oil collecting ring groove is fixed on the upper outer wall of the cyclone separator, and the cyclone separator is equipped with a second liquid level gauge, and the oil collecting ring groove is connected to a sewage treatment plant together with the first oil discharge pipe through the second oil discharge pipe; the oil storage tank comprises an external floating roof cover and a baffle ring for arranging a rain collecting trough and a mixing ring groove, the mixing ring groove is connected to the side cut inlet pipe through a first hose, and the rain collecting trough is connected to the first branch pipe, the second branch pipe and the third branch pipe through a second hose; the oil-water separation system can improve the processing flow and separation effect at a lower cost.

Description

Technical Field

[0001] The present invention relates to the technical field of petrochemical emission treatment, in particular to an external floating roof oil tank sewage oil-water separation system. Background Art

[0002] Large oil depots typically feature external floating roofs. During the oil delivery process, oil adheres to the tank walls, a process known as "wall hanging." As the floating roof descends, the tank walls become exposed. During rainy days, this oil is washed down by rainwater and flows into initial rainwater collection devices. Currently, initial rainwater collection devices installed in large oil depots are structurally unable to automatically separate rainwater from sewage. Operators rely entirely on their experience to determine rainfall volume and timing, and then manually switch between these systems. This setup is significantly influenced by individual factors and is not very practical. During heavy rains, clean rainwater often mixes with the sewage system, impacting downstream sewage treatment plants. Furthermore, rainwater with excessive oil content cannot be discharged directly.

[0003] Although the existing oil-water separation technology is relatively mature, what is needed now is low-cost initial treatment upstream, and it cannot replace the complex treatment of sewage treatment plants downstream. Therefore, sedimentation tanks or gravity tanks that rely on density difference stratification have become the first choice. They can not only perform initial separation of oil and water, but also have a very low cost. However, the defect is also very obvious, that is, the separation effect is poor, especially in heavy rain seasons with heavy rainfall. Rainwater mixed with crude oil has no time to stratify. If the volume of the gravity tank is expanded, it will occupy scarce land area, which is not worth the cost. Summary of the Invention

[0004] In order to overcome the deficiencies in the background technology and solve existing technical problems, the present invention discloses an external floating roof oil tank sewage oil-water separation system, which can improve the processing flow and separation effect at a relatively low cost.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] The invention relates to an external floating roof oil tank sewage discharge oil-water separation system, comprising an oil storage tank, a cyclone separator, a gravity separation tank and a downstream sewage treatment plant for collecting and treating oil pollution; the gravity separation tank is divided into a floating tank and an overflow tank by a partition wall, and an overflow gate is provided at the lower part of the partition wall. The floating tank and the overflow tank are respectively provided with a first oil drain pipe and a first water drain pipe at the upper end of the tank wall away from the overflow gate, and a first liquid level gauge is installed on the wall of the floating tank between the first oil drain pipe and the overflow gate; the lower port of the cyclone separator is connected to a discharge pipe with the end thereof extending into the floating tank, and the upper port of the cyclone separator is provided with an overflow notch on the side wall away from the side cut-in pipe, and an oil collecting ring groove is fixedly provided around the upper outer wall of the cyclone separator, and the oil collecting ring groove is fixed to the upper outer wall of the cyclone separator. A second liquid level gauge is installed on the wall of the cyclone separator between the side-cut inlet pipes, and the bottom of the oil collecting ring groove is connected to the sewage treatment plant together with the first oil drain pipe through a second oil drain pipe; the oil storage tank includes an external floating roof cover that can float up and down along the tank wall, and the upper cover surface of the external floating roof cover is coaxially fixed with a baffle ring to divide the inside and outside of the baffle ring into a rain collecting trough and a mixing ring groove. The bottom of the mixing ring groove is connected to the side-cut inlet pipe through a first hose, and the bottom of the rain collecting trough is connected to a first branch pipe with an end corresponding to the upper port of the cyclone separator, a second branch pipe with an end corresponding to the notch of the floating separation tank, and a third branch pipe for emptying the end through a second hose. The first branch pipe, the second branch pipe, the third branch pipe, the first hose and the discharge pipe are all equipped with control valves.

[0007] Furthermore, an air intake ring pipe is provided at the center of the bottom of the floating tank, and a plurality of upward air intake branches are evenly arranged on the tube body of the air intake ring pipe. The air intake ring pipe is connected to the air intake main pipe, and a one-way valve for one-way air intake is installed on the air intake main pipe. The outer end of the air intake main pipe is sealed and passes through the floating tank and is connected to the air intake pump.

[0008] Furthermore, a slow-flow water wheel is provided in the discharge pipe, and the air intake pump is configured as a hand-cranked air intake pump. The axle of the slow-flow water wheel rotates through the wall of the discharge pipe and is correspondingly connected to the rocking shaft of the air intake pump.

[0009] Furthermore, the oil storage tank, cyclone separator and gravity separation tank are arranged in sequence from high to bottom, and a water pump is installed on the first hose.

[0010] Furthermore, an oil drain valve and an oil pump are installed on both the first oil drain pipe and the second oil drain pipe.

[0011] Furthermore, the bottoms of the flotation tank and the overflow tank are both provided with drain pipes with drain valves.

[0012] Due to the adoption of the above-mentioned technical solution, the present invention has the following beneficial effects:

[0013] The external floating roof oil tank sewage discharge oil-water separation system disclosed by the present invention can collect most of the clean rainwater that does not contact the tank wall and a small part of the mixed oil and water that contacts the tank wall separately by adding a flow-blocking ring to the external floating roof cover, thereby reducing the processing volume; by adding a cyclone separator, the oil and water are firstly separated by centrifugal action, which improves the separation effect and reduces the flow rate, so that the oil and water entering the gravity separation tank can be effectively separated for a second time in a limited space, and the entire separation process is carried out continuously, so that the processing requirements can be met even when the rainfall is large. More importantly, the entire system has a simple structure, does not require too much manual operation, and can be controlled at a low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the implementation structure of the present invention;

[0015] Figure 2 2 is a schematic diagram of the top view of the cyclone separator.

[0016] In the figure: 1. Oil storage tank; 101. External floating roof; 102. Baffle ring; 2. Cyclone separator; 201. Side cut inlet pipe; 202. Oil collecting ring groove; 203. Overflow notch; 204. Second liquid level gauge; 3. Gravity separation tank; 301. Floating separation tank; 302. Overflow tank; 303. Overflow gate; 304. First liquid level gauge; 4. Sewage treatment plant; 5. First hose; 6. Second hose; 7. First branch pipe; 8. Second branch pipe; 9. Third branch pipe; 10. Second oil discharge pipe; 11. Discharge pipe; 12. Slow-flow water wheel; 13. Intake pump; 14. Intake main pipe; 15. First oil discharge pipe; 16. Intake ring pipe; 17. First drain pipe. DETAILED DESCRIPTION

[0017] The technical solutions of the present invention will be described below with reference to the accompanying drawings in the embodiments of the present invention. In the description, it should be understood that if there are terms such as "upper", "lower", "front", "rear", "left", "right" and the like indicating directions or positional relationships, these are merely for the purpose of corresponding to the drawings of the present invention and for the convenience of describing the present invention. They do not indicate or imply that the devices or components referred to must have a specific direction. Example 1:

[0018] Combined with attachment Figure 1 and 2 The external floating roof oil tank sewage oil-water separation system comprises an oil storage tank 1, a cyclone separator 2, a gravity separation tank 3 and a downstream sewage treatment plant 4 for collecting and treating oil pollution. The oil storage tank 1, the cyclone separator 2 and the gravity separation tank 3 can be arranged in sequence from high to low to facilitate the natural flow of rainwater.

[0019] The gravity separation tank 3 is divided into a floating tank 301 and an overflow tank 302 by a partition wall. The volume and length of the floating tank 301 are larger than those of the overflow tank 302, ensuring that the oil and water stay in the floating tank 301 for a longer time, which is conducive to stratification. As needed, the bottom of the floating tank 301 and the overflow tank 302 are both provided with a sewage pipe with a sewage valve, which is convenient for cleaning and drainage after long-term use. The lower part of the partition wall is provided with an overflow door 303, and after the floating tank 301 is stratified, the rainwater below can flow out. The oil flows through the overflow gate 303 and enters the overflow trough 302, while the upper oil layer is blocked by the isolation wall. The first oil discharge pipe 15 and the first water discharge pipe 17 are respectively provided at the upper end of the trough wall of the float separation trough 301 and the overflow trough 302 away from the overflow gate 303. A first liquid level gauge 304 is installed on the trough wall of the float separation trough 301 between the first oil discharge pipe 15 and the overflow gate 303. The first liquid level gauge 304 is generally slightly higher than the overflow gate 303, so as to facilitate the control of water discharge above the overflow gate 303 in advance.

[0020] The lower port of the cyclone separator 2 is connected to a discharge pipe 11 whose end extends into the flotation tank 301, and the end of the discharge pipe 11 must also be away from the overflow gate 303. An overflow notch 203 is provided on the side wall of the upper port of the cyclone separator 2 away from the side-cut inlet pipe 201. An oil collecting ring groove 202 is fixedly provided around the upper outer wall of the cyclone separator 2. After centrifugation, the oil can enter the oil collecting ring groove 202 through the overflow notch 203 for preliminary separation and collection. A second liquid level gauge 204 is installed on the wall of the cyclone separator 2 between the oil collecting ring groove 202 and the side-cut inlet pipe 201, which is convenient for controlling the discharge of water in advance to fill most of the space of the cyclone separator 2. The bottom of the oil collecting ring groove 202 is connected to the sewage treatment plant 4 together with the first oil drain pipe 15 through the second oil drain pipe 10. As needed, the first oil drain pipe 15 and the second oil drain pipe 10 are both equipped with oil drain valves and oil pumps, which can control the oil discharge volume and provide oil discharge power when needed;

[0021] The oil storage tank 1 includes an external floating roof 101 that can float up and down along the tank wall. A baffle ring 102 is coaxially fixed to the upper cover surface of the external floating roof 101 to divide the baffle ring 102 into a rain collecting trough and a mixing ring trough inside and outside. The rain collecting trough and the mixing ring trough can collect most of the clean rainwater that does not contact the tank wall in the middle and a small part of the mixed oil and water that contacts the tank wall, respectively, thereby reducing the processing volume; the bottom of the mixing ring trough is connected to the side cut inlet pipe 201 through a first hose 5; when the transmission power is insufficient, a water pump can be installed on the first hose 5 as needed; the bottom of the rain collecting trough is distributed through a second hose 6 with a first branch pipe 7 corresponding to the upper port of the cyclone separator 2, a second branch pipe 8 corresponding to the slot of the floating separation tank 301, and a third branch pipe 9 for emptying the end. The first branch pipe 7, the second branch pipe 8, the third branch pipe 9, the first hose 5 and the discharge pipe 11 are all equipped with control valves.

[0022] In the embodiment of the external floating roof oil tank sewage oil-water separation system of the present invention, when the tank wall of the oil storage tank 1 is exposed and it rains, the control valves on the first hose 5, the third branch pipe 9 and the discharge pipe 11 are first controlled to be closed, and the control valves on the first branch pipe 7 and the second branch pipe 8 are opened, and the clean rainwater collected by the rain collecting trough is put into the cyclone separator 2 and the gravity separation tank 3, and stops when the water level reaches the detection level of the second liquid level gauge 204 and the first liquid level gauge 304, and then feedback control is performed to close the control valves on the first branch pipe 7 and the second branch pipe 8, and the first hose 5, the third branch pipe 9 and the discharge pipe 11 are opened. The control valve on the pipe 11 allows the oil and water in the mixing ring groove to enter the cyclone separator 2 first. After centrifugal separation, most of the oil overflows from the overflow gap 203 into the oil collecting ring groove 202, and is then discharged into the sewage treatment plant 4 through the second oil discharge pipe 10. A small amount of oil and rainwater slowly pass through the discharge pipe 11 into the flotation tank 301, and then undergo gravity stratification. After stratification, the lower layer of rainwater enters the overflow tank 302 through the overflow gate 303 and is discharged through the first drain pipe 17. After stratification, the upper layer of oil is discharged into the sewage treatment plant 4 from the first oil discharge pipe 15. Example 2:

[0023] When the rainfall is heavy, the gravity separation tank 3 performs continuous flow stratification. In order to enhance the stratification effect, based on the first embodiment, an air intake ring 16 is set at the center of the bottom of the float tank 301. The pipe body of the air intake ring 16 is evenly ringed with multiple upward air intake branches. The air intake ring 16 is connected to the air intake main pipe 14. A one-way valve for one-way air intake is installed on the air intake main pipe 14 to prevent backflow. The outer end of the air intake main pipe 14 is sealed and passes through the float tank 301 and is connected to the air intake pump 13. Micro bubbles are injected into the float tank 301 through the air intake pump 13 and the air intake ring 16. These bubbles adhere to the surface of the oil droplets. The buoyancy of the oil droplets is increased, thereby pushing the oil droplets to float to the water surface for easy separation; as needed, a slow-flow water wheel 12 is provided in the discharge pipe 11, and the fluid in the discharge pipe 11 can be used to push the slow-flow water wheel 12 to rotate, thereby slowing down the flow rate, so that the fluid can enter the gravity separation tank 3 at a low speed to facilitate stratification. At the same time, the air intake pump 13 can be set as a hand-cranked air intake pump, and the wheel axle of the slow-flow water wheel 12 rotates through the wall of the discharge pipe 11 and is correspondingly connected to the shaking shaft of the air intake pump 13. The rotation energy of the slow-flow water wheel 12 is used to work and inflate the hand-cranked air intake pump, thereby reducing energy consumption and reducing control costs.

[0024] The parts of the present invention that are not described in detail are prior art. It is obvious to those skilled in the art that the present invention is not limited to the details of the above-mentioned exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, no matter from which point of view, the above-mentioned embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is limited by the appended claims rather than the above description. Therefore, it is intended that all changes that fall within the meaning and scope of the equivalent elements of the claims are included in the present invention, and any figure marks in the claims should not be regarded as limiting the content of the claims involved.

Claims

1. An external floating roof oil tank sewage oil-water separation system, characterized by: The invention comprises an oil storage tank (1), a cyclone separator (2), a gravity separation tank (3) and a downstream sewage treatment plant (4) for collecting and treating oil pollution; the gravity separation tank (3) is divided into a floating tank (301) and an overflow tank (302) by a partition wall, an overflow gate (303) is provided at the lower part of the partition wall, and the floating tank (301) and the overflow tank (302) are respectively provided with a first oil discharge pipe (15) and a first water discharge pipe (17) at the upper end of the tank wall away from the overflow gate (303). A first liquid level gauge (304) is installed on the wall of the floating tank (301) between the oil discharge pipe (15) and the overflow gate (303); the lower port of the cyclone separator (2) is connected to the discharge pipe (11) whose end extends into the floating tank (301); an overflow notch (203) is provided on the side wall of the upper port of the cyclone separator (2) away from the side cut-in pipe (201); an oil collecting ring groove (202) is fixedly provided around the upper outer wall of the cyclone separator (2); the oil collecting ring groove (202) is connected to the side cut-in pipe (201) and the oil collecting ring groove (202) is fixed to the side cut-in pipe (201). A second liquid level gauge (204) is installed on the wall of the cyclone separator (2) between the cut-in pipes (201); the bottom of the oil collecting ring groove (202) is connected to the sewage treatment plant (4) through the second oil discharge pipe (10) and the first oil discharge pipe (15); the oil storage tank (1) includes an external floating roof (101) that can float up and down along the tank wall; a baffle ring (102) is coaxially fixed to the upper cover surface of the external floating roof (101) to divide the baffle ring (102) into a rain collecting groove and a mixing ring groove inside and outside. The bottom of the mixing ring groove is connected to the side cut inlet pipe (201) through a first hose (5); the bottom of the rainwater collecting groove is connected to a first branch pipe (7) whose end corresponds to the upper port of the cyclone separator (2), a second branch pipe (8) whose end corresponds to the notch of the floating separation tank (301), and a third branch pipe (9) for emptying the end through a second hose (6); the first branch pipe (7), the second branch pipe (8), the third branch pipe (9), the first hose (5) and the discharge pipe (11) are all equipped with control valves.

2. The external floating roof tank sewage oil-water separation system according to claim 1 is characterized by: An air intake ring pipe (16) is provided at the center of the bottom of the floating tank (301), and a plurality of upward air intake branches are evenly arranged around the body of the air intake ring pipe (16). The air intake ring pipe (16) is connected to an air intake main pipe (14), and a one-way valve for one-way air intake is installed on the air intake main pipe (14). The outer end of the air intake main pipe (14) is sealed and passes through the floating tank (301) and is connected to an air intake pump (13).

3. The external floating roof tank sewage oil-water separation system according to claim 2 is characterized by: A slow-flow water wheel (12) is provided in the discharge pipe (11), and the air intake pump (13) is a hand-cranked air intake pump. The axle of the slow-flow water wheel (12) rotates through the wall of the discharge pipe (11) and is correspondingly connected to the rocking shaft of the air intake pump (13).

4. The external floating roof tank sewage oil-water separation system according to claim 1 is characterized by: The oil storage tank (1), cyclone separator (2) and gravity separation tank (3) are arranged in sequence from high to low, and a water pump is installed on the first hose (5).

5. The external floating roof tank sewage oil-water separation system according to claim 1 is characterized by: An oil discharge valve and an oil pump are installed on both the first oil discharge pipe (15) and the second oil discharge pipe (10).

6. The external floating roof tank sewage oil-water separation system according to claim 1 is characterized by: The bottoms of the flotation tank (301) and the overflow tank (302) are both provided with drainage pipes with drainage valves.

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