A device and method for flash recovery of water vapor separation and closed sewage transportation of a spherical tank

Abstract

The application belongs to the technical field of petrochemical liquid hydrocarbon storage and transportation, and specifically discloses a device and a method for flash recovery of gas-liquid separation of water cutting of a spherical tank and closed conveying of sewage, which comprises a spherical tank and a tank root valve, the bottom of the spherical tank is connected with an inlet valve, a water cutting tank, a water cutting pipeline, a flash tank and a drainage pipeline in sequence through a water inlet pipeline, a float ball valve is arranged in the flash tank to prevent gas from being discharged, a water cutting valve is arranged on the water cutting pipeline, the output end of the water cutting pipeline extends into the flash tank, the top of the flash tank is connected with an exhaust pipeline, the bottom of the flash tank is connected with a drainage pipeline, and a pneumatic booster drainage device is arranged on the drainage pipeline. The device can recover gaseous hydrocarbons and sewage after gas-liquid separation in the flash tank respectively, can complete the drainage work under the condition of pneumatic boosting, and can complete the closed conveying of sewage to a sewage treatment plant directly, thereby avoiding the harm caused by the sewage retention in a sewage tank or a sewage pool.

Description

Technical Field

[0001] This invention belongs to the field of petrochemical liquefied hydrocarbon storage and transportation technology, and specifically relates to a device and method for flash evaporation recovery and closed-loop transportation of wastewater in a spherical tank for water-gas-liquid separation. Background Technology

[0002] In existing technologies, a certain amount of water will accumulate at the bottom of the spherical tanks storing liquefied hydrocarbons, which needs to be treated by water removal in a timely manner. Then, the water is separated into gas and liquid by passing it through a low-pressure container, namely a flash tank that can separate gas and liquid, to ensure that the discharged water does not contain volatile gases, and to better recover the vaporized liquefied hydrocarbons. The discharged wastewater is then transported to the sewage pipeline in a closed manner to meet the requirements of safety and environmental protection.

[0003] like Figure 1 As shown, the bottom of the spherical tank 1' is connected in sequence to a water-cutting tank 2' and a low-pressure flash tank 3' for facilitating gas-liquid separation via connecting pipes. An inlet valve 8' and a water-cutting valve 9' are respectively installed at the inlet and outlet of the water-cutting tank 2'. An interface gauge 7' is also installed inside the water-cutting tank 2' to detect the hydrocarbon / water interface. A drain pipe 4' is connected to the bottom of the flash tank 3', and a drain valve 10' and a closed-loop pump 11' are installed on the drain pipe 4'. After gas-liquid separation in the flash tank 3', opening the drain valve 10' and the closed-loop pump 11' allows the wastewater to be discharged. As water is gradually discharged from the flash tank 3' or gaseous hydrocarbons are gradually discharged through the exhaust pipe 7' (which is also equipped with a speed limiting valve 12'), the internal pressure of the flash tank 3' is low, and the wastewater discharge process is slow, only flowing by gravity to a pressureless wastewater tank or an underground wastewater pipe. If a pneumatic pressurization device is added to the drain pipe 4' to speed up the discharge of sewage and increase the pressure, the sewage can be directly transported to the sewage treatment plant through the pressurized sewage pipe in a closed manner, thus avoiding environmental pollution.

[0004] Therefore, it is urgent to develop a flash evaporation recovery device and method for spherical tank water-gas-liquid separation that allows for rapid drainage and direct, sealed transport of wastewater to wastewater treatment plants. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and specifically disclose a flash evaporation recovery device for gas-liquid separation in a spherical tank and a closed sewage conveying device. This device can recover gaseous hydrocarbons and sewage after gas-liquid separation in the flash tank, and can complete the drainage work under pneumatic pressurization. It can directly transport sewage to the sewage treatment plant through pipelines, avoiding the harm caused by sewage stagnation in sewage tanks or sewage ponds.

[0006] To achieve the above-mentioned technical objectives, the present invention is implemented according to the following technical solution: The device for flash evaporation recovery and closed-loop sewage transportation of gas-liquid separation using a spherical tank according to the present invention includes a spherical tank and a tank root valve. The bottom of the spherical tank is sequentially connected to an inlet valve, a water-cutting tank, a water-cutting pipeline, a flash tank, and a drain pipeline via an inlet pipeline. The flash tank is equipped with a float valve with a hollow float inside. The bottom of the flash tank is equipped with a float valve seat. When the liquid level drops to the lowest position, the hollow float will fall to the bottom of the flash tank, blocking the outlet and preventing gas from escaping. In this way, the float valve prevents gas from escaping from the flash tank. A water-cutting valve is installed on the water-cutting pipeline, and the output end of the water-cutting pipeline extends into the flash tank. An exhaust pipeline is connected to the top of the flash tank, and a drain pipeline is connected to the bottom of the flash tank. A pneumatic booster drainage device is installed on the drain pipeline.

[0007] As a further improvement to the above technology, a first check valve and a second check valve are installed sequentially on the drainage pipeline, and the pneumatic booster drainage device is connected to the position between the first check valve and the second check valve through an air connection pipe.

[0008] As a further improvement to the above technology, the pneumatic booster drainage device includes a piston-type pneumatic pump, a controller, an air source valve, and an external air source, which are connected in sequence through an air passage connecting pipe. The piston-type pneumatic pump includes a piston cylinder, a piston, and a drive block mounted on the piston. The drive block is provided with an upward air passage for driving the piston to move upward and a downward air passage for driving the piston to move downward. The upward air passage is connected to an external driving air pressure, and the downward air passage is connected to an air passage connecting pipe at the bottom of the controller. When the piston rises to the top of the piston cylinder, the controller is driven to open the air source valve to connect the external air source.

[0009] As a further improvement to the above technology, the top of the flash tank is provided with an atomizing nozzle at the end of the water cutting pipeline.

[0010] As a further improvement to the above technology, the density of the hollow float is between that of water and liquefied hydrocarbons.

[0011] As a further improvement to the above technology, the diameter of the hollow float of the float valve is 30-150 mm.

[0012] As a further improvement to the above technology, the exhaust pipe is provided with a speed limiting exhaust valve, a pressure reducing valve, and a pressure gauge P for monitoring pressure.

[0013] This invention also discloses a method for flash evaporation recovery and closed-loop wastewater conveying device for water-gas-liquid separation in the above-mentioned spherical tank, the specific steps of which are as follows: (1) Water cutting process: Open the tank root valve and inlet valve. Due to the density difference, the water at the bottom of the spherical tank will automatically enter the water cutting tank. The liquefied hydrocarbon in the water cutting tank will automatically return to the spherical tank. After the water level reaches the set height, the water cutting tank will cut the water. (2) Gas-liquid separation process: Water at the bottom of the water-cutting tank enters the flash tank through the water-cutting pipeline. After entering the low-pressure flash tank, the solubility of liquefied hydrocarbons in water decreases due to the reduced pressure. The liquefied hydrocarbons dissolved in the water will be vaporized into gaseous hydrocarbons, which will rise into the exhaust pipeline and then be connected to the low-pressure gas or flare gas pipeline for recovery. The separated water is temporarily stored in the flash tank and discharged through the drain pipeline. (3) Pressurized drainage process: When there is water in the flash tank, the first one-way valve opens automatically, the second one-way valve is closed, and a certain pressure of driving air is introduced into the rising air passage. The driving block will move upward and pump the sewage into the piston cylinder. When the driving block moves and drives the top of the piston to touch the top of the inner wall of the piston cylinder, the controller drives the opening of the air source valve to connect the external air source. The gas from the external air source enters the descending air passage and drives the driving block and piston to move downward. At this time, the first one-way valve opens automatically and the second one-way valve opens automatically. When the piston moves downward, it will discharge the pressurized water temporarily stored in the piston cylinder to the sewage pipe. (4) After the above steps (3) are repeated multiple times, the water in the flash tank is drained, the float in the flash tank descends and blocks the outlet of the float valve, and the pneumatic booster drainage device automatically stops operating.

[0014] Furthermore, the pressure in step (3) above is 0-60 kPa.

[0015] Compared with the prior art, the beneficial effects of the present invention are: (1) The device for flash evaporation recovery and closed sewage transportation of the spherical tank water gas-liquid separation according to the present invention has a fast drainage speed and high drainage efficiency due to the addition of a pneumatic booster drainage device to the original drainage pipeline. The whole process is carried out in a fully enclosed environment, which prevents the environmental pollution caused by the volatilization of organic matter in sewage into the air. (2) In this invention, when the pneumatic booster drainage device moves the piston upward to the end, it triggers the controller, which then opens the air source. The air will enter the drive block and drive the drive block and piston downward to discharge the sewage that has been drawn into the piston cylinder. Because the pressure inside the piston cylinder is large, the sewage discharge speed is fast and the drainage efficiency is high. Attached Figure Description

[0016] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments: Figure 1 This is a schematic diagram of the structure of a spherical tank water cutting and recycling device in the prior art; Figure 2 This is a schematic diagram of the device for flash evaporation recovery and closed-loop sewage transportation of water gas-liquid separation in a spherical tank according to the present invention. Detailed Implementation

[0017] like Figure 2As shown, the device for flash evaporation recovery and closed-loop sewage transportation of water-gas-liquid separation in a spherical tank according to the present invention includes a spherical tank 1 and a tank root valve 2. The bottom of the spherical tank 1 is sequentially connected to an inlet valve 3, a water-cutting tank 4, a water-cutting pipeline 5, a flash evaporator 6, and a drain pipeline 20 via a water inlet pipeline 10. The water-cutting tank 4 is also equipped with a level gauge 50 for detecting the liquid level. The flash evaporator 6 is equipped with a float valve 8 with a hollow float ball 81. A float valve seat 18 is located at the bottom of the flash evaporator 6. When the float descends to its lowest position, the hollow float 81 will fall to the bottom of the flash tank 6, blocking the outlet and preventing gas from escaping. At this time, the float valve 8 can prevent the gas in the flash tank 6 from escaping. In addition, a water-cutting valve 7 is installed on the water-cutting pipe 5, and the output end of the water-cutting pipe 5 extends into the flash tank 6. The top of the flash tank 6 is connected to the exhaust pipe 30, and the bottom of the flash tank 6 is connected to the drain pipe 20. A pneumatic pressurized drain device is installed on the drain pipe 20.

[0018] In this invention, a first check valve 11 and a second check valve 12 are sequentially installed on the drainage pipe 20, and the pneumatic booster drainage device is connected to the position between the first check valve 11 and the second check valve 12 through the air connection pipe 40.

[0019] The top of the flash tank 6 is located at the end of the water cutting pipe 5 and is equipped with an atomizing nozzle 19, which can easily form the mixture of liquefied hydrocarbons and water entering the flash tank 6 into a mist, increasing the surface area for evaporation. Then, in a low-pressure environment, the gaseous hydrocarbons and water are quickly separated. The gaseous hydrocarbons enter the exhaust pipe 30 for output, while the water is temporarily stored inside the flash tank 6.

[0020] In this invention, the density of the hollow float 8 is between that of water and liquefied hydrocarbons, and the diameter of the hollow float 8 is 30-150 mm.

[0021] The pneumatic booster drainage device includes a piston-type pneumatic pump 9, a controller 13, an air source valve 14, and an external air source 15, which are connected in sequence through an air passage connection pipe 40. The piston-type pneumatic pump 9 includes a piston cylinder 91, a piston 92, and a drive block 93 mounted on the piston 92. The drive block 93 is provided with an upward air passage 931 for driving the piston 92 to move upward and a downward air passage 932 for driving the piston 92 to move downward. The upward air passage 931 is connected to external driving air pressure, and the downward air passage 932 is connected to the air passage connection pipe 40 at the bottom of the controller 13. When the piston 92 rises to the top of the piston cylinder 91, the controller 13 is driven to open the air source valve 14 to connect the external air source 15.

[0022] The exhaust pipe 30 is equipped with a speed limiting exhaust valve 16, a pressure reducing valve 17, and a pressure gauge P for monitoring pressure. When the gas flow rate on the exhaust pipe 30 is large, the speed limiting exhaust valve 16 limits the flow rate and the pressure reducing valve 17 reduces the pressure appropriately to ensure safe use.

[0023] This invention also discloses a method for flash evaporation recovery of the above-mentioned spherical tank water-gas-liquid separation flash evaporation recovery device, the specific steps of which are: (1) Water cutting process: Open the tank root valve 2 and the inlet valve 3. Due to the density difference, the water at the bottom of the spherical tank 1 will automatically enter the water cutting tank 4. The liquefied hydrocarbon in the water cutting tank 4 will automatically return to the spherical tank. After the water level reaches the set height, the water cutting tank 4 will cut the water. (2) Gas-liquid separation process: Water at the bottom of the water-cutting tank 4 enters the flash tank 6 through the water-cutting pipe 5. After entering the low-pressure flash tank 6, the solubility of liquefied hydrocarbons in water decreases due to the reduced pressure. The liquefied hydrocarbons dissolved in the water will be vaporized into gaseous hydrocarbons, which rise into the exhaust pipe 30 and are then connected to the low-pressure gas or flare gas pipeline for recovery. The separated water is temporarily stored in the flash tank 6 and discharged through the drain pipe 20. (3) Pressurized drainage process: When there is water in the flash tank 6, the first one-way valve 11 automatically opens, the second one-way valve 12 is closed, and a driving air pressure of 50 kPa is introduced into the rising air passage 931. The driving block 93 will move upward and pump the sewage into the piston cylinder 91. When the driving block 93 moves and drives the top of the piston 92 to touch the top of the inner wall of the piston cylinder 91, the controller 13 drives the opening of the air source valve 14 and connects the external air source 15. The gas from the external air source 15 enters the descending air passage 932 and drives the driving block 93 and the piston 92 to move downward. At this time, the first one-way valve 11 automatically opens and the second one-way valve 12 automatically opens. When the piston 92 moves downward, it will discharge the pressurized water temporarily stored in the piston cylinder 91 to the sewage pipe. (4) After the above steps (3) are repeated multiple times, the water in the flash tank 6 is drained, the float ball 81 in the flash tank 6 descends and blocks the bottom outlet of the flash tank 6, and the pneumatic booster drainage device automatically stops operating.

[0024] This invention is not limited to the above-described embodiments. Any modifications or variations to this invention that do not depart from the spirit and scope of this invention are also included in this invention if they fall within the scope of the claims and equivalent technologies of this invention.

Claims

1. A device for flash evaporation recovery and closed-loop sewage transportation via spherical tank for water-gas-liquid separation, comprising a spherical tank and a tank root valve, characterized in that: The bottom of the spherical tank is sequentially connected to an inlet valve, a water-cutting tank, a water-cutting pipeline, a flash tank, and a drain pipeline via an inlet pipe. The flash tank is equipped with a float valve with a hollow float ball. The bottom of the flash tank is equipped with a float valve seat. When the liquid level drops and the hollow float ball reaches its lowest position, the hollow float ball will fall to the bottom of the flash tank. The float valve prevents the gas inside the flash tank from escaping. A water-cutting valve is installed on the water-cutting pipeline, and the output end of the water-cutting pipeline extends into the flash tank. An exhaust pipeline is connected to the top of the flash tank, and a drain pipeline is connected to the bottom of the flash tank. A pneumatic booster drainage device is installed on the drain pipeline.

2. The device for flash evaporation recovery and closed-loop sewage conveying of water-gas-liquid separation in a spherical tank according to claim 1, characterized in that: The drainage pipeline is equipped with a first check valve and a second check valve in sequence, and the pneumatic booster drainage device is connected to the position between the first check valve and the second check valve through an air connection pipe.

3. The device for flash evaporation recovery and closed-loop sewage conveying of water-gas-liquid separation in a spherical tank according to claim 2, characterized in that: The pneumatic booster drainage device includes a piston-type pneumatic pump, a controller, an air source valve, and an external air source, which are connected in sequence through an air passage connecting pipe. The piston-type pneumatic pump includes a piston cylinder, a piston, and a drive block mounted on the piston. The drive block is provided with an upward air passage for driving the piston to move upward and a downward air passage for driving the piston to move downward. The upward air passage is connected to an external driving air pressure, and the downward air passage is connected to an air passage connecting pipe at the bottom of the controller. When the piston rises to the top of the piston cylinder, the controller opens the air source valve to connect the external air source.

4. The device for flash evaporation recovery and closed-loop sewage conveying of water-gas-liquid separation in a spherical tank according to claim 2, characterized in that: The top of the flash tank is equipped with an atomizing nozzle located at the end of the water cutting pipeline.

5. The device for flash evaporation recovery and closed-loop sewage conveying of water vapor-liquid separation in a spherical tank according to claim 2, characterized in that: The density of the hollow buoy is between that of water and liquefied hydrocarbons.

6. The device for flash evaporation recovery and closed-loop sewage conveying of water-gas-liquid separation in a spherical tank according to claim 1, characterized in that: The diameter of the hollow float of the float valve is 30-150 mm.

7. The device for flash evaporation recovery and closed-loop sewage conveying of water-gas-liquid separation in a spherical tank according to claim 1, characterized in that: The exhaust pipe is equipped with a speed-limiting exhaust valve, a pressure-reducing valve, and a pressure gauge P for monitoring pressure.

8. The method for flash evaporation recovery and closed-loop sewage conveying of a spherical tank for water-gas-liquid separation according to any one of claims 1 to 7, wherein the specific steps are as follows: (1) Water cutting process: Open the tank root valve and inlet valve. Due to the density difference, the water at the bottom of the spherical tank will automatically enter the water cutting tank. The liquefied hydrocarbon in the water cutting tank will automatically return to the spherical tank. After the water level reaches the set height, the water cutting tank will cut the water. (2) Gas-liquid separation process: Water at the bottom of the water-cutting tank enters the flash tank through the water-cutting pipeline. After entering the low-pressure flash tank, the solubility of liquefied hydrocarbons in water decreases due to the reduced pressure. The liquefied hydrocarbons dissolved in the water will be vaporized into gaseous hydrocarbons, which will rise into the exhaust pipeline and then be connected to the low-pressure gas or flare gas pipeline for recovery. The separated water is temporarily stored in the flash tank and discharged through the drain pipeline. (3) Pressurized drainage process: When there is water in the flash tank, the first one-way valve opens automatically, the second one-way valve is closed, and a certain pressure of driving air is introduced into the rising air passage. The driving block will move upward and pump the sewage into the piston cylinder. When the driving block moves and drives the top of the piston to touch the top of the inner wall of the piston cylinder, the controller drives the opening of the air source valve to connect the external air source. The gas from the external air source enters the descending air passage and drives the driving block and piston to move downward. At this time, the first one-way valve closes automatically and the second one-way valve opens automatically. When the piston moves downward, it will discharge the pressurized water temporarily stored in the piston cylinder to the sewage pipe. (4) After the above steps (3) are repeated multiple times, the water in the flash tank is drained, the float in the flash tank descends and blocks the outlet of the float valve, and the pneumatic booster drainage device automatically stops operating.

9. The method for flash evaporation recovery and closed-loop sewage conveying of a spherical tank for water-gas-liquid separation according to claim 8, characterized in that: The pressure in step (3) above is within the range of 0-60 kPa.

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