Novel accident oil and water storage system

Abstract

The invention relates to a novel accident oil and water storage system which comprises a water inlet energy dissipation pipe, an overflow weir, an oil collection system, a water outlet well and an overflow pipe, and the oil collection system comprises an oil separation area, an oil collection groove, an oil collection well and an oil separation wall; the water inlet energy dissipation pipe comprises a large-diameter pipe section and a small-diameter pipe section, and the small-diameter pipe section is fixed to the bottom and provided with a vertically-upward water inlet. The overflow weir is arranged around the vertically upward water inlet; a drainage pump, a water outlet well liquid level meter and an overflow pipe are arranged in the water outlet well; and a manual butterfly valve is arranged on the overflow pipe. The reducing pipeline, the vertical upward water inlet and the overflow weir around the water inlet are arranged at the water inlet pipeline, so that water inlet energy caused by height difference is eliminated, the rainwater drainage pump and the liquid level meter are arranged in the water well and are only used for rainwater drainage under the non-accident working condition, the operation mode of manual starting and automatic pump stopping is adopted, and the working efficiency is greatly improved. And the volume of the accident oil reservoir is not occupied by rainwater.

Description

Technical Field

[0001] The present invention relates to power plant facilities, and more particularly to a new type of accident oil and water storage system. Background Art

[0002] The transformers in nuclear power plants are outdoor oil-filled equipment. According to the requirements of fire protection codes, a water spray fire protection system is generally installed. Under non-accident conditions in a nuclear power plant, during the rainy season, the rainwater collected in the outdoor transformer pit is drained into the accident oil storage tank through the accident drain pipe. Under accident conditions, to ensure the safety of the transformer and prevent the spread of fire, the water spray fire extinguishing system sprays a large amount of fire-fighting water quickly. The transformer starts the oil discharge measure, and the accident oil-water mixture is collected in the transformer pit and then drained into the accident oil storage tank through the accident drain pipe.

[0003] According to the requirements of fire protection codes, when a transformer has an accident and catches fire, the effective volume of the accident oil tank should be considered according to 100% of the accident oil volume of the largest transformer. For large nuclear power plants, such as 1000MW nuclear power units in coastal areas, the accident oil volume of the largest transformer is about 68m3. In addition, according to the requirements of fire protection design, the corresponding water spray design fire-fighting water volume for the transformer is about 720m3, and the water volume of the outdoor fire hydrant is 108m3.

[0004] The existing accident oil storage tank in a nuclear power plant mainly consists of an inlet pipe, a front separation well, an oil separation area, an oil collection tank, an oil collection well, an oil separation wall, an outlet well, an outlet pipe, etc., as Figure 1 shown.

[0005] Under non-accident conditions, the rainwater collected in the outdoor transformer pit during the rainy season flows by gravity through the buried drainage pipe to the accident oil storage tank. When the water level in the outlet well of the accident oil storage tank is lower than the bottom elevation of the outlet pipe, the rainwater is intercepted in the accident oil storage tank; when the water level in the outlet well of the accident oil storage tank is higher than the bottom elevation of the outlet pipe, the rainwater above the bottom elevation of the outlet pipe is discharged to the plant rainwater pipe network through the outlet pipe.

[0006] Under accident conditions, a large amount of fire-fighting water and accident oil drainage from the transformer are collected in the transformer pit. The oil-water mixture flows by gravity through the buried drainage pipeline to the accident oil storage tank. The oil-water mixture undergoes oil-water separation in the oil separation area. The lighter transformer oil floats above the oil-water interface in the oil separation area after separation, while the fire-fighting water is below the oil-water interface in the oil separation area. The oil separation wall blocks the separated transformer oil in the oil separation area. The excess fire-fighting water enters the outlet well through the water passing holes at the lower end of the oil separation wall. When the water level in the outlet well is higher than the bottom elevation of the outlet pipe, the fire-fighting water above the bottom of the outlet pipe is discharged through the outlet pipe into the factory rainwater pipe network. After the accident ends, the inlet and outlet pipes of the accident oil storage tank are blocked with disc flange blind flanges. Then, water is filled into the separation well in front to raise the water level in the tank, so that the accident oil overflows to the oil collection well through the oil collection trough. Finally, the accident oil drainage is pumped out from the oil collection well with a mobile oil pump and uniformly treated by the power plant. After the accident oil is removed, the inlet and outlet flange blind flanges are removed to restore the normal operation state of the system.

[0007] For the currently designed accident oil storage tank, to meet the requirement of the oil storage volume, the bottom of the accident oil storage tank is relatively deep. However, the inlet pipe is horizontally connected to the accident oil storage tank, and the height from the bottom of the pipe to the bottom of the accident oil storage tank is generally greater than 3m. When the water level in the accident oil storage tank is relatively low, the drop height is relatively large, which causes relatively large erosion to the bottom of the tank.

[0008] Under accident conditions, a large amount of oil-water mixture enters the accident oil storage tank. On the one hand, due to the absence of a liquid level gauge, it is impossible to ensure that the accumulated water level in the accident oil storage tank is higher than the top elevation of the water passing holes at the lower end of the oil separation wall. When the water level in the oil storage tank is lower than the top elevation of the water passing holes at the lower end of the oil separation wall, in the initial stage, the oil-water mixture directly enters the outlet well through the water passing holes at the lower end of the oil separation wall. On the other hand, it is very difficult to ensure that the accident oil-water mixture is completely separated in the oil separation area, which will also cause some oil-containing wastewater to enter the outlet well through the water passing holes at the lower end of the oil separation wall. The above two aspects of the oil-water mixture are finally discharged into the factory rainwater pipe network and then discharged outside the factory, polluting the external environment of the factory. According to the latest environmental assessment requirements of the power plant, under accident conditions, the accident oil and water need to be stored in a closed oil tank and not discharged outside. Therefore, the current accident oil storage tank cannot meet the current environmental protection requirements. In addition, the elevation of the outlet pipe of the current accident oil storage tank is lower than that of the inlet pipe. To meet the requirement of gravity drainage, the elevation of the factory rainwater pipe network connected to it is relatively low, resulting in a relatively large burial depth of the entire factory rainwater pipe network and increasing the investment in the factory rainwater pipe network. Summary of the Invention

[0009] The object of the present invention is to optimize and improve the accident oil storage tank, avoid the erosion of the bottom of the accident oil storage tank caused by the large height difference of the accident oil-water drop, and reduce the damage to the accident oil storage tank caused by the water flow impact; the new accident oil storage tank can store all the oil-water mixture under accident conditions in the water tank without discharging it into the factory area rainwater pipe network, thus avoiding polluting the natural water body and meeting the current strict environmental protection requirements; it has a low requirement for the pipe network elevation of the rainwater intake pipe, effectively reducing the cost of the factory area rainwater pipe network.

[0010] This application discloses a new type of accident oil and water storage system, and the new type of accident oil and water storage system includes: an inlet energy dissipation pipe, an overflow weir, an oil collection system, an outlet well, and an overflow pipe, wherein:

[0011] The oil collection system includes: an oil separation area, an oil collection tank, an oil collection well, and an oil separation wall; the oil collection tank is arranged in the middle of the oil separation area and is connected to the oil collection well, and the bottom of the oil separation wall is provided with water passing holes;

[0012] The inlet energy dissipation pipe includes a large-diameter pipe section and a small-diameter pipe section, the large-diameter pipe section and the small-diameter pipe section are connected by a reducer connector, the large-diameter pipe section is connected to the accident oil storage tank inlet pipe, and the small-diameter pipe section is fixed at the bottom and is provided with a vertically upward inlet;

[0013] The overflow weir is arranged around the vertically upward inlet;

[0014] A drainage pump, an outlet well liquid level gauge and an overflow pipe are arranged in the outlet well, the outlet well liquid level gauge is configured to give an alarm when the water level in the outlet well is higher than the alarm high water level, and a manual butterfly valve is arranged on the overflow pipe.

[0015] In a preferred example, a ventilation pipe is arranged at the top of the oil separation area.

[0016] In a preferred example, an oil separation area liquid level gauge is arranged in the oil separation area.

[0017] In a preferred example, the volume of the oil storage tank is the sum of the maximum accident oil volume of a single device in a single fire, the fire fighting drainage volume and the maximum daily rainfall volume.

[0018] In a preferred example, the elevation of the top of the overflow weir is higher than that of the vertically upward inlet.

[0019] In a preferred example, the manual butterfly valve is normally closed.

[0020] In a preferred example, the elevation of the overflow pipe is higher than that of the inlet pipe.

[0021] In a preferred example, the number of the drainage pumps is not less than two.

[0022] In a preferred embodiment, the oil separation area level gauge is configured to remind the operator to replenish water to the accident oil storage tank in a timely manner to a level 0.1 m above the alarm low water level when the water level is lower than the alarm low water level, and the alarm low water level is not lower than the water passing hole.

[0023] In a preferred embodiment, a sump is arranged inside the outlet well to ensure the water absorption of the drainage pump and increase the volume of the accident oil storage tank.

[0024] The advantages of the present invention are as follows:

[0025] (1) By providing a vertically upward water inlet and a water inlet energy dissipation pipe to dissipate the energy of the water entering the accident oil storage tank, the accident oil storage tank is protected from being scoured by the falling water, and the service life of the accident oil storage tank is extended.

[0026] (2) Under non-accident conditions, through the alarm of the level gauge arranged in the oil tank, the operator is reminded to manually start the rainwater drainage pump to drain the rainwater collected in the accident oil storage tank into the factory area rainwater pipe network, so as to ensure that the volume of the accident oil storage tank is not occupied by rainwater, and the manual pump start can avoid the automatic pump start due to the high water level under accident conditions. The pump stop is interlocked with the water level, reducing the working intensity of the operator.

[0027] (3) Under accident conditions, through the design of the volume of the oil storage tank, all the accident oil-water mixture can be stored in the accident oil storage tank, and oil-water separation is carried out in the oil separation area. The oil-water mixture is prevented from entering the factory area rainwater pipe network, avoiding polluting the external environment of the factory.

[0028] (4) An overflow pipe with a elevation higher than the water inlet pipe is provided, which can discharge the excess fire water that exceeds the specification requirements and has undergone oil-water separation into the factory area rainwater pipe network; it can also reduce the elevation requirements of the factory area rainwater pipe network, thereby reducing the cost of the factory area rainwater pipe network. The manual butterfly valve on the overflow pipe is normally in the closed state to prevent the factory area rainwater pipe network from backflowing into the accident oil storage tank and occupying the effective volume of the oil tank. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is the accident oil storage tank in the prior art;

[0030] Figure 2 is the plan view of the accident oil storage tank according to an embodiment of the present invention;

[0031] Figure 3 is Figure 2 the sectional view of the accident oil storage tank in

[0032] Figure 4 is Figure 2 the sectional view of the accident oil storage tank in

[0033] Reference numerals:

[0034] 1 - Large - diameter pipe section; 2 - Small - diameter vertical pipe section; 3 - Overflow weir; 4 - Vent pipe; 5 - Oil - separation area; 6 - Oil - separation area liquid level gauge; 7 - Vent hole; 8 - Oil - collecting trough; 9 - Oil - collecting well; 10 - Overflow pipe; 11 - Outlet well; 12 - Sump pit; 13 - Inlet pipe; 14 - Reducer connector; 15 - Small - diameter horizontal pipe section; 16 - Vertically - upward inlet; 17 - Oil - separation wall. Detailed implementation manners

[0035] The inventor of the present invention invented a new type of accident - storage oil - water system. Compared with the prior art, a reduced - diameter pipe, a vertically - upward inlet, and an overflow weir around the inlet are provided at the inlet pipeline, and the elevation of the top of the overflow weir is higher than the elevation of the vertically - upward inlet. It can eliminate the inlet energy caused by the height difference and avoid the direct scouring of the inlet on the bottom plate or wall of the accident - storage oil tank. And a rainwater drainage pump and a liquid level gauge are arranged in the outlet well, which are only used for rainwater discharge under non - accident conditions, and adopt a manual - start and automatic - pump - stop operation mode. It can not only ensure that the volume of the accident - storage oil tank is not occupied by rainwater, but also avoid discharging the oil - water mixture into the factory area rainwater pipe network due to the automatic start of the pump under high water level conditions during accident conditions, and an overflow pipe is provided, and a manual butterfly valve is installed on the overflow pipe. The manual butterfly valve usually remains in a normally - closed state to ensure that the rainwater in the factory area rainwater pipe network does not back - flow into the accident - storage oil tank. It is only opened during accident conditions and when the fire - fighting duration exceeds the specified standard to discharge the excess fire - fighting water after oil - water separation into the factory area rainwater pipe network.

[0036] The present invention will be described in detail below in conjunction with the embodiments shown in the drawings. However, it should be noted that these embodiments are not limitations on the present invention, and any equivalent transformation or substitution in function, method, or structure made by those of ordinary skill in the art according to these embodiments shall fall within the protection scope of the present invention.

[0037] The following elaborates on the specific implementation process of the present invention through examples.

[0038] Example:

[0039] An embodiment of the present invention is as Figures 1 - 4 shown. This embodiment includes: an inlet energy - dissipation pipe, an overflow weir 3, an oil - collecting system, an outlet well 11, and an overflow pipe 10, where:

[0040] The oil collection system includes: an oil separation area 5, an oil collection tank 8, an oil collection well 9, and an oil separation wall 17; a ventilation pipe 4 is provided at the top of the oil separation area 5, the oil collection tank 8 is arranged in the middle of the affiliated oil separation area 5 and is connected to the oil collection well 9, and water passing holes are arranged at the bottom of the oil separation wall 17. Optionally, in one embodiment, the oil separation area 5 is equipped with an oil separation area liquid level gauge 6, and the oil separation area liquid level gauge 6 is configured to remind the operator to replenish water to the accident oil storage tank in time to a level 0.1 m above the alarm low water level when the water level is lower than the alarm low water level, and the alarm low water level is not lower than the water passing holes. Optionally, in another embodiment, the oil collection tank 8 is equipped with a vent hole 7

[0041] Optionally, in one embodiment, the volume of the oil storage tank is the sum of the maximum accident oil volume of a single device in a single fire, the fire fighting drainage volume, and the maximum daily rainfall volume

[0042] The water inlet energy dissipation pipe includes a large-diameter pipe section 1 and a small-diameter pipe section. The large-diameter pipe section 1 and the small-diameter pipe section are connected by a reducer connector 14. The small-diameter pipe section includes a small-diameter vertical pipe section 2 and a small-diameter vertical pipe section 15. The large-diameter pipe section 1 is connected to the accident oil storage tank water inlet pipe 1, and the small-diameter horizontal pipe section 15 is fixed at the bottom and is provided with a vertically upward water inlet 16;

[0043] The overflow weir 3 is arranged around the vertically upward water inlet 16, and the crest elevation of the overflow weir 3 is higher than that of the vertically upward water inlet 16;

[0044] A drainage pump, an outlet well liquid level gauge, and an overflow pipe 10 are arranged in the outlet well 11. The outlet well liquid level gauge is configured to give an alarm when the water level in the outlet well is higher than the alarm high water level. A manual butterfly valve is arranged on the overflow pipe 10, and the manual butterfly valve is normally closed. And the elevation of the overflow pipe 10 is higher than that of the water inlet pipe.

[0045] Optionally, in one embodiment, the number of the drainage pumps is not less than two.

[0046] Optionally, in one embodiment, a sump 12 is arranged inside the outlet well to ensure the water absorption of the drainage pump and increase the volume of the accident oil storage tank

[0047] The series of detailed descriptions listed above are only specific descriptions of the feasible implementation manners of the present invention, and they are not intended to limit the protection scope of the present invention. Any equivalent implementation manners or changes made without departing from the technical spirit of the present invention should be included in the protection scope of the present invention.

[0048] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above-described exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, in any aspect, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be embraced within the present invention. Any reference signs in the claims should not be construed as limiting the claims involved.

[0049] In addition, it should be understood that although this specification is described in terms of embodiments, not every embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A new type of accident oil and water storage system, characterized in that, the new type of accident oil and water storage system includes: an inlet energy dissipation pipe, an overflow weir, an oil collection system, an outlet well, and an overflow pipe, where: the oil collection system includes: an oil separation area, an oil collection tank, an oil collection well, and an oil separation wall; the oil collection tank is arranged in the middle of the oil separation area and is connected to the oil collection well, and the bottom of the oil separation wall is provided with water passing holes; the inlet energy dissipation pipe includes a large-diameter pipe section and a small-diameter pipe section, the large-diameter pipe section and the small-diameter pipe section are connected by a reducer connector, the large-diameter pipe section is connected to the inlet pipe of the accident oil storage tank, and the small-diameter pipe section is fixed at the bottom and is provided with a vertically upward inlet; the overflow weir is arranged around the vertically upward inlet; a drainage pump, an outlet well liquid level gauge, and an overflow pipe are arranged in the outlet well, the outlet well liquid level gauge is configured to alarm when the water level in the outlet well is higher than the alarm high water level, and a manual butterfly valve is arranged on the overflow pipe.

2. The new type of accident oil and water storage system according to claim 1, characterized in that, a ventilation pipe is arranged at the top of the oil separation area.

3. The new type of accident oil and water storage system according to claim 1, characterized in that, an oil separation area liquid level gauge is arranged in the oil separation area.

4. The new type of accident oil and water storage system according to claim 1, characterized in that, the volume of the oil storage tank is the sum of the maximum accident oil volume of a single device in a single fire, the fire fighting drainage volume, and the maximum daily rainfall volume.

5. The new type of accident oil and water storage system according to claim 1, characterized in that, the elevation of the top of the overflow weir is higher than that of the vertically upward inlet.

6. The new type of accident oil and water storage system according to claim 1, characterized in that, the manual butterfly valve is normally closed.

7. The new type of accident oil and water storage system according to claim 1, characterized in that, the elevation of the overflow pipe is higher than that of the inlet pipe.

8. The new type of accident oil and water storage system according to claim 1, characterized in that, the number of the drainage pumps is not less than two.

9. The new type of accident oil and water storage system according to claim 1, characterized in that, the oil separation area liquid level gauge is configured to remind the operator to replenish water to the accident oil storage tank in time to a level above the alarm low water level by 0.1 m when the water level is lower than the alarm low water level, and the alarm low water level is not lower than the water passing hole.

10. The new type of accident oil and water storage system according to claim 1, characterized in that, a sump is arranged inside the outlet well to ensure the suction of the drainage pump and increase the volume of the accident oil storage tank.

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