A fully automatic opening and draining treatment and monitoring system for a marine liquefied natural gas terminal

Abstract

This invention discloses a fully automated discharge and monitoring system for offshore liquefied natural gas (LNG) terminals, relating to the field of marine engineering technology. The system includes an oil-water separator, with an oily wastewater inlet at one end. Inside the separator, along the flow direction of the oily wastewater, interconnected components are installed: an inlet rectifier baffle, a corrugated plate assembly, a coalescing element, an oil collection tank, a weir, and a clear water tank. The oily wastewater undergoes oil-water separation via the corrugated plate assembly. The separated wastewater is further separated into clear water by the coalescing element and enters the clear water tank via the weir. The clear water tank is connected to a discharge pipeline equipped with a discharge control valve. The separated oily wastewater enters the oil collection tank, which is connected to the inlet pipeline of an oily wastewater pump. The outlet pipeline of the oily wastewater pump is connected to a shuttle oily wastewater tank. A sampling discharge valve is installed at the bottom of the shuttle oily wastewater tank, connected to the oily wastewater inlet of the oil-water separator via a floor drain. This invention can independently complete the collection, treatment, and discharge of oily wastewater.

Description

Technical Field

[0001] This invention relates to the field of marine engineering technology, and more particularly to a fully automated system for the opening, discharging, processing, and monitoring of offshore liquefied natural gas terminals. Background Technology

[0002] Open drainage systems are an indispensable part of offshore LNG terminals. They are mainly used to collect deck rainwater, cleaning wastewater, and oil sludge discharged at atmospheric pressure on offshore LNG terminals. Typically, these fluids are collected through floor drains and stored in open drainage tanks. They are then pumped into closed drainage systems or production systems via open drainage pumps, and finally discharged into the sea through subsea pipelines or treated by the production water system to reduce pollution to the marine environment. Clean rainwater and open drainage tank overflows are discharged directly into the sea.

[0003] In existing technologies, conventional open discharge tanks lack advanced treatment capabilities, possessing only storage and simple gravity settling functions, which cannot meet the clean water discharge standards for oily wastewater. Conventional open discharge wastewater can only be treated via subsea pipelines or production water treatment systems. However, for platforms without subsea pipeline access or production water treatment, such as LNG terminals and other offshore facilities, conventional open discharge systems are unusable. Furthermore, open discharge wastewater transported via subsea pipelines can contaminate production fluids, waste energy, and cause pipeline corrosion. Conventional open discharge pipelines lack control and monitoring functions, lacking real-time and total discharge monitoring and automatic shutdown capabilities, and cannot perform online monitoring and discharge control of wastewater discharged into the sea.

[0004] When offshore liquefied natural gas (LNG) terminals have large deck areas or are located in areas with high rainfall, it is usually necessary to design large-sized open-drainage tanks and install large-capacity open-drainage pumps. This results in high equipment investment, large land area, and significant fluctuations in the production system, affecting production. In addition, since the open-drainage tanks are located at the lowest point of the platform, the open-drainage pumps are positioned even lower to ensure net positive suction head (NPSH), which can lead to damage to the pumps from waves and cause oil leaks and pollution. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a device that can independently complete the collection, treatment and discharge of oily wastewater.

[0006] To address the aforementioned technical problems, this invention provides a fully automated open-loop discharge treatment and monitoring system for offshore liquefied natural gas terminals, comprising an oil-water separator, an oil sludge pump, and a shuttle oil sludge tank. One end of the oil-water separator has an oily wastewater inlet. Inside the oil-water separator, along the flow direction of the oily wastewater, interconnected inlet rectifier baffles, corrugated plate assemblies, coalescing elements, an oil collection trough, a weir plate, and a clear water trough are sequentially installed. The oily wastewater undergoes oil-water separation via the corrugated plate assemblies. The separated wastewater undergoes secondary separation into clear water via the coalescing elements and enters the clear water trough via the weir plate. The clear water trough is connected to a discharge pipeline equipped with a discharge control valve. The separated oily wastewater enters the oil collection trough, which is connected to the inlet pipeline of the oil sludge pump. The outlet pipeline of the oil sludge pump is connected to the shuttle oil sludge tank. A sampling discharge valve is installed at the bottom of the shuttle oil sludge tank, and the sampling discharge valve is connected to the oily wastewater inlet of the oil-water separator via a floor drain.

[0007] According to a preferred embodiment of the present invention, a clean water level sensor is installed in the clean water tank, and the clean water level sensor controls the opening and closing of the discharge control valve.

[0008] According to a preferred embodiment of the present invention, an oil-water analyzer sensor is installed on the discharge pipeline, and the oil-water analyzer sensor controls the opening and closing of the discharge control valve.

[0009] According to a preferred embodiment of the present invention, an oil level sensor is provided in the oil collection tank, and the oil level sensor controls the drive air switch valve provided on the oil pump.

[0010] According to a preferred embodiment of the present invention, a sludge flow sensor is installed on the outlet pipeline of the sludge pump, and the sludge flow sensor controls the drive air switch valve provided on the sludge pump.

[0011] According to a preferred embodiment of the present invention, a flexible hose is provided between the outlet pipeline of the sludge pump and the shuttle sludge tank, and the hose port is provided with a quick-release interface.

[0012] According to a preferred embodiment of the present invention, the top of the oil-water separator is provided with a vent pipe equipped with a flame arrester.

[0013] According to a preferred embodiment of the present invention, the sludge pump is a top-mounted self-priming pneumatic diaphragm pump.

[0014] According to a preferred embodiment of the present invention, the top of the shuttle sludge tank is provided with a vent pipe with a flame arrester and a safety valve.

[0015] According to a preferred embodiment of the present invention, a depth gauge is inserted through the top of the shuttle oily waste tank.

[0016] The technical advantages of this invention are as follows:

[0017] 1. This invention discloses a fully automated open-loop discharge treatment and monitoring system for offshore liquefied natural gas (LNG) terminals, comprising an oil-water separator, an oil sludge pump, and a shuttle oil sludge tank. Oily wastewater enters the oil-water separator through its inlet inlet, where its flow is stabilized by a flow rectifier baffle. The stabilized fluid then undergoes oil-water separation via a corrugated plate assembly. The separated oil sludge is collected in an oil collection tank, while the separated water undergoes secondary separation via a coalescing element at the bottom of the oil collection tank. The resulting qualified clean water flows through a weir into a clear water tank, which is equipped with a discharge pipeline and a control valve for discharge into the sea. The oil collection tank is connected to an oil sludge pump, which transports the oil sludge from the tank to the shuttle oil sludge tank. The oil sludge in the tank undergoes gravity settling and is discharged through a sampling discharge valve. The water layer at the bottom of the tank then re-enters the oil-water separator for treatment via a floor drain. This system enables the open-loop discharge system to independently complete collection, treatment, and discharge, eliminating dependence on other systems and achieving functional independence. It can be widely used in various offshore facilities and has broad application prospects.

[0018] 2. The oil-water separator of the present invention is equipped with an inlet rectifier baffle, a corrugated plate assembly and an oil collection tank. A metal coalescing element is installed at the bottom of the oil collection tank and a weir plate is installed on the other side of the oil tank. After the oily wastewater is separated into oil and water, qualified clean water overflows from the weir plate into the clean water tank. Automatic discharge to the sea is achieved by controlling the liquid level through the automatic discharge valve on the discharge pipeline, which ensures the treatment effect of the open discharge system.

[0019] 3. The discharge pipeline of this invention is equipped with an oil-water analyzer sensor for continuous water quality monitoring. When the water quality does not meet the discharge standards, it will automatically shut off and trigger an alarm. At the same time, a discharge flow meter is installed to monitor the flow rate and total amount of sewage discharged, realizing online control and monitoring of open discharge and preventing environmental pollution.

[0020] 4. In this invention, sludge is collected in an oil collection tank. The sludge level sensor activates the sludge pump, which transports the sludge to a shuttle sludge tank for storage. The shuttle sludge tank is top-mounted, and the sludge in the tank settles by gravity. When the bottom sampling and discharge valve samples the sludge and it passes the test, the water layer at the bottom of the tank can be periodically discharged and re-entered into the oil-water separator for treatment. This greatly extends the turnover cycle of the shuttle sludge tank, significantly reduces equipment size and discharge capacity, reduces the space requirements of offshore liquefied natural gas terminals, and saves on equipment investment, platform investment, and operating costs.

[0021] 5. The present invention adopts a top-mounted self-priming pneumatic diaphragm pump for sludge and oil, which avoids damage to the pump and oil spill pollution caused by the upward waves. At the same time, the sludge and oil pump inlet switching valve realizes the sludge and oil transportation or the cleaning operation of the oil-water separation tank. A flexible hose is installed between the sludge and oil pump outlet pipeline and the shuttle sludge and oil tank to facilitate the disassembly, assembly and transfer of the shuttle sludge and oil tank, which realizes the convenience of on-site personnel. Attached Figure Description

[0022] Figure 1This is a schematic diagram of a fully automated discharge treatment and monitoring system for offshore liquefied natural gas terminals according to the present invention.

[0023] Reference numerals: 1-Oil-water separator; 2-Oil-sludge pump; 3-Shuttle oil-sludge tank; 4-Inlet rectifier baffle; 5-Corrugated plate assembly; 6-Oil collection tank; 7-Gathering element; 8-Weir plate; 9-Vortex breaker; 10-Oil-sludge level sensor; 11-Clear water level sensor; 12-Discharge control valve; 13-Oil-water analyzer sensor; 14-Discharge flow meter; 15-Oil-sludge pump filter; 16-Drive air switch valve; 17-Oil-sludge pump switching valve; 18-Oil-sludge flow sensor; 19-Hose; 20-Sampling discharge valve; 21-Depth gauge; 22-Vent pipe with flame arrester; 23-Safety valve; 24-Manhole; 25-Handhole. Detailed Implementation

[0024] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the invention.

[0025] like Figure 1 As shown, this invention provides a fully automated open-loop treatment and monitoring system for offshore liquefied natural gas (LNG) terminals, including an oil-water separator 1, an oily waste pump 2, and a shuttle oily waste tank 3. One end of the oil-water separator 1 has an oily wastewater inlet. Inside the oil-water separator 1, along the flow direction of the oily wastewater, are sequentially installed interconnected inlet rectifier baffles 4, corrugated plate assemblies 5, coalescing elements 7, oil collection troughs 6, weirs 8, and clear water troughs. The oily wastewater undergoes oil-water separation via the corrugated plate assembly 5. The separated oily wastewater... Water is separated into clear water through the coalescing element 7 and enters the clear water tank through the weir plate 8. The clear water tank is connected to the sea discharge pipeline, which is equipped with a sea discharge control valve 12. The separated sludge enters the oil collection tank 6, which is connected to the inlet pipeline of the sludge pump 2. The outlet pipeline of the sludge pump 2 is connected to the shuttle sludge tank 3. The bottom of the shuttle sludge tank 3 is equipped with a sampling discharge valve 20, which is connected to the oily wastewater inlet of the oil-water separator 1 through a floor drain.

[0026] like Figure 1 As shown, the present invention includes an oil-water separator 1, a sludge pump 2, and a shuttle sludge tank 3.

[0027] Oily wastewater from both hazardous and non-hazardous areas enters the oily wastewater inlet of oil-water separator 1 through separate manifolds. The flow is stabilized by the inlet rectifier baffle 4. The stabilized fluid then undergoes oil-water separation via corrugated plate assembly 5. The separated oil is collected in oil collection tank 6, while the separated water undergoes secondary separation via coalescing elements 7 at the bottom of oil collection tank 6. The resulting qualified clean water flows through weir plate 8 into clear water tank. A clear water level sensor 11 in the clear water tank controls the discharge control valve 12. When the level reaches a certain height, the discharge control valve 12 automatically opens to discharge water into the sea. An oil-water analyzer 13 is installed on the discharge pipeline for continuous water quality monitoring and to control the discharge valve 12. If the water quality does not meet the discharge standards, the discharge control valve 12 automatically shuts off and an alarm sounds. Simultaneously, a discharge flow meter 14 is installed on the discharge pipeline to monitor the flow rate and total discharge volume.

[0028] An oil level sensor 10 is installed in the oil collection tank 6 to control the drive air switch valve 16 of the oil pump 2. When the oil level reaches a certain height, the drive air switch valve 16 opens, and the drive air drives the oil pump 2 to transport the oil in the oil collection tank 6 through the oil pump filter 15 to the shuttle oil tank 3. An oil flow sensor 18 is installed at the outlet of the oil pump 2 to measure the total amount of oil and control the drive air switch valve 16 of the oil pump 2. When the shuttle oil tank 3 is close to full, the oil flow sensor 18 alarms and closes the drive air switch valve 16 of the oil pump 2.

[0029] The sludge in the shuttle oil tank 3 settles by gravity. When the bottom sampling discharge valve 20 takes a qualified sample, the water layer in the lower part of the tank can be discharged periodically through the sampling discharge valve 20 and re-enter the oil-water separator 1 through the floor drain for treatment.

[0030] Preferably, manholes 24 are provided on the tank body at the inlet end of the oil-water separator 1, on both sides of the corrugated plate group 5 and on both sides of the weir plate 8, and manholes 24 are provided in each space unit of the tank body, so that personnel can easily enter the interior of the oil-water separator 1 during maintenance.

[0031] The top of the oil-water separator 1 is equipped with a vent pipe 22 with a flame arrester, which can discharge flammable and dangerous gases volatilized in the tank.

[0032] Preferably, an oil level sensor 10 is installed in the oil collection tank 6, which controls the drive air switch valve 16 installed on the oil pump 2. The oil obtained from oil-water separation is collected in the oil collection tank 6. When the liquid level reaches a certain high level, the oil level sensor 10 in the oil tank automatically starts the oil pump 2 and transports it to the shuttle oil tank 3 for storage.

[0033] Preferably, a clean water level sensor 11 is installed inside the clean water tank, and the clean water level sensor 11 controls the opening and closing of the discharge control valve 12. A vortex breaker 9 is also installed at the bottom of the clean water tank.

[0034] Preferably, an oil-water analyzer sensor 13 is installed on the discharge pipeline. The oil-water analyzer sensor 13 continuously monitors the water quality and controls the opening and closing of the discharge control valve 12. When the water quality does not meet the discharge requirements, the discharge control valve 12 is shut off and an alarm is triggered. At the same time, a discharge flow meter 14 is installed on the discharge pipeline to monitor the flow rate and total amount of sewage discharged.

[0035] Preferably, the sludge pump 2 is a top-mounted self-priming pneumatic diaphragm pump to prevent damage and oil spillage caused by rising water. Simultaneously, the inlet pipeline of the sludge pump 2 extends into both the inside and outside of the oil collection tank 6 of the oil-water separator 1, and a sludge pump switching valve 17 is installed. Through the sludge pump switching valve 17, sludge transportation or cleaning operations of the oil-water separator 1 can be achieved. The discharge capacity of the sludge pump 2 can be designed according to the amount of sludge in the oil collection tank 6 and the volume of the oil collection tank 6, thereby significantly reducing the pump's discharge capacity.

[0036] An oil flow sensor 18 is installed on the outlet pipeline of the oil pump 2. The oil flow sensor 18 controls the drive air switch valve 16 installed on the oil pump 2. The oil pump outlet is set with a total oil volume and automatically measures and shuts off the flow. When the shuttle oil tank 3 is close to full, an alarm is triggered and the oil pump 2 is automatically shut off to prevent overflow.

[0037] A flexible hose 19 is installed between the outlet pipeline of the sludge pump 2 and the shuttle sludge tank 3. The hose 19 has a quick-release interface at its port, which can be quickly disconnected during transfer, facilitating the disassembly, assembly, and transfer of the shuttle sludge tank 3.

[0038] Preferably, a top-mounted shuttle oily waste tank 3 is used, with a switching valve and a sampling and discharge valve 20 installed at the bottom of the shuttle oily waste tank 3. After the oily waste in the tank settles by gravity, when the sample taken by the bottom sampling and discharge valve 20 is qualified, the water layer in the lower part of the tank can be discharged periodically and re-entered into the oil-water separator 1 for treatment, which greatly extends the turnover cycle of the shuttle oily waste tank 3.

[0039] The shuttle oily waste tank 3 is equipped with a depth gauge 21 on its top. Instead of a level gauge, the shuttle oily waste tank 3 is equipped with a depth gauge 21 to avoid damage during the transfer operation. Personnel can check the liquid level inside the tank through the depth gauge 21.

[0040] The shuttle sludge tank 3 is protected by a vent pipe 22 with a flame arrester and a safety valve 23 at its top. During normal operation, the vent pipe 22 with the flame arrester is open to release flammable and hazardous gases volatilized from the tank. During shuttle transfer, the vent pipe 22 with the flame arrester is closed, and overpressure protection is provided through the safety valve 23. A manhole 25 is also provided for convenient personnel maintenance.

[0041] The above-described embodiments are merely preferred embodiments provided to fully illustrate the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are all within the scope of protection of the present invention. The scope of protection of the present invention is defined by the claims.

Claims

1. A fully automated open-loop discharge treatment and monitoring system for offshore liquefied natural gas terminals, comprising an oil-water separator, an oil sludge pump, and a shuttle oil sludge tank, characterized in that, One end of the oil-water separator is provided with an oily wastewater inlet. Inside the oil-water separator, along the flow direction of the oily wastewater, an interconnected inlet rectifier baffle, a corrugated plate assembly, a coalescing element, an oil collection tank, a weir plate, and a clear water tank are installed sequentially. The oily wastewater undergoes oil-water separation through the corrugated plate assembly. The separated wastewater undergoes secondary separation through the coalescing element into clear water and enters the clear water tank through the weir plate. The clear water tank is connected to a discharge pipeline, which is equipped with a discharge control valve. The separated sludge enters the oil collection tank, which is connected to the inlet pipeline of a sludge pump. The outlet pipeline of the sludge pump is connected to a shuttle sludge tank. The bottom of the shuttle sludge tank is equipped with a sampling discharge valve, which is connected to the oily wastewater inlet of the oil-water separator through a floor drain. A clean water level sensor is installed inside the clean water tank, and the clean water level sensor controls the opening and closing of the discharge control valve. An oil-water analyzer sensor is installed on the discharge pipeline, and the oil-water analyzer sensor controls the opening and closing of the discharge control valve; The oil collection tank is equipped with an oil level sensor, which controls the drive air switch valve on the oil pump. The sludge pump is a top-mounted self-priming pneumatic diaphragm pump.

2. The fully automated discharge and monitoring system for offshore liquefied natural gas terminals according to claim 1, characterized in that, A sludge flow sensor is installed on the outlet pipeline of the sludge pump, and the sludge flow sensor controls the drive air switch valve installed on the sludge pump.

3. The fully automated discharge and monitoring system for offshore liquefied natural gas terminals according to claim 1, characterized in that, A flexible hose is installed between the outlet pipeline of the sludge pump and the shuttle sludge tank, and the hose port is equipped with a quick-release interface.

4. The fully automated discharge and monitoring system for offshore liquefied natural gas terminals according to claim 1, characterized in that, The oil-water separator is equipped with a vent pipe with a flame arrester at the top.

5. The fully automated discharge and monitoring system for offshore liquefied natural gas terminals according to claim 1, characterized in that, The shuttle oily waste tank is equipped with a vent pipe with a flame arrester and a safety valve at the top.

6. The fully automated discharge and monitoring system for offshore liquefied natural gas terminals according to claim 1, characterized in that, A depth gauge is installed on the top of the shuttle oil sludge tank.

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