A LNG vertical storage tank monitoring and pressure buffer device

Abstract

The invention relates to a LNG vertical storage tank monitoring and pressure buffering device, which is mainly composed of a parameter monitoring unit, a storage tank pressure buffering unit and a folding and rotating structure, and integrates multiple functions such as multi-parameter monitoring in the storage tank, reducing the storage tank pressure, and preventing LNG stratification and rolling, so as to realize LNG storage tank state monitoring and pressure buffering and extend the LNG storage time; the storage tank parameter monitoring unit is designed, and the liquid level, liquid phase density, gas-liquid two-phase temperature and pressure and component monitoring are realized through a capacitive liquid level meter, a density sensor, a temperature sensor, a pressure sensor and a component detection system; the pressure buffering unit is designed, and LNG is sprayed from the top of the storage tank through a pressure reducing nozzle under pressure to reduce the storage tank pressure, and the monitoring device blades rotate to reduce the maximum density difference of LNG and prevent stratification and rolling; the folding and rotating structure is designed, and the monitoring unit can be retracted into the main axis of the monitoring device to reduce the tank opening.

Description

Technical Field

[0001] The invention relates to a LNG vertical storage tank monitoring and pressure buffer device, belonging to the technical field of monitoring technology and automation device. Background Art

[0002] Storing LNG in tanks is a common storage method. With the development of LNG storage technology, the requirements for the intelligence of tanks are getting higher and higher. The ability to accurately and comprehensively monitor the state parameters such as temperature and pressure of the stored materials in the tanks is an important indicator of the level of intelligence.

[0003] During the storage of LNG, due to the inevitable heat exchange process, LNG will evaporate to form BOG, causing the pressure of the storage tank to increase. In order to prevent the occurrence of safety accidents, the overpressure BOG needs to be released. Therefore, reducing the pressure of the LNG storage tank, reducing the release amount of BOG, and delaying the storage time of LNG can not only reduce the waste of energy, but also protect the environment and reduce carbon emissions.

[0004] LNG in the tank will form stratification due to the difference in density. When the maximum density difference of LNG in the tank is too large, once the boundary layers of each layer disappear, the LNG will roll violently, produce a large amount of BOG, and the tank pressure will rise sharply. Therefore, monitoring the density of LNG in the tank and taking preventive measures against stratification and rolling are of great practical significance to the safe operation of the tank.

[0005] At present, the common tank monitoring devices use a separate monitoring method to monitor the target tank parameters, which leads to a lot of modifications to the tanks, causing changes in the mechanical properties of the tanks themselves. After a certain period of use, the tanks are prone to failure, and even serious failures may lead to leakage of stored materials, causing major safety accidents. Therefore, the degree of modification to the tanks is an important indicator of whether the monitoring device is feasible.

[0006] Therefore, in order to solve the above problems, an LNG vertical tank monitoring and pressure buffer device is designed, which can monitor the liquid level, LNG density, temperature, pressure and composition of the gas-liquid two-phase in the tank, and at the same time reduce the tank pressure and prevent LNG stratification and rolling. The installation of the device requires little modification to the tank. Summary of the invention

[0007] The purpose of the present invention is to provide a LNG vertical storage tank monitoring and pressure buffering device, which is designed with a storage tank multi-parameter monitoring unit, a pressure buffering unit and a folding and rotating structure, and can monitor the liquid level, LNG density, temperature, pressure and composition of the gas-liquid two-phase in the storage tank, while effectively reducing the tank pressure and the maximum density difference of LNG, extending the LNG storage time, and realizing the safe storage of LNG.

[0008] The present invention mainly solves the following problems:

[0009] (1) Design a multi-parameter monitoring unit for storage tanks. Through a capacitive level meter, density sensor, temperature sensor, pressure sensor, and component detection system, the liquid level, liquid phase density, gas-liquid two-phase temperature and pressure, and components in the storage tank are monitored to increase the diversity of storage tank monitoring parameters and improve monitoring accuracy.

[0010] (2) Design a pressure buffer unit. Under pressure, LNG is sprayed from the top of the tank through a pressure-reducing nozzle to reduce the tank pressure. The blades of the monitoring device rotate to reduce the maximum density difference of LNG and prevent stratification and tumbling.

[0011] (3) A folding and rotating structure is designed, and the monitoring unit is retracted into the main axis of the monitoring device. The installation of the device requires little modification to the storage tank, which increases the service life of the storage tank and ensures the safe operation of the storage tank.

[0012] In order to achieve the above object, the technical solution of the present invention is as follows.

[0013] An LNG vertical storage tank monitoring and pressure buffer device comprises a vertical storage tank 1, a three-way plug valve 6, a flange 7, a rotating slider 8, a capacitive liquid level gauge 20, a rotating lifting module 30, a folding arm 40, a lifting rod 12, a paddle 52, a sleeve 60, a gas collection pipe 70, a gas collection bottle 71, a heater 72, a first electric control valve 73, a pressure reducing pipe 100, a second electric control valve 101, and a pressure reducing nozzle 102;

[0014] The top of the vertical storage tank 1 is reserved with an opening, the monitoring device is installed inside the vertical storage tank 1 through a flange 7, the bottom of the vertical storage tank 1 is connected to the heater 72 through a gas collecting pipe 70b, the gas collecting pipe 70b is installed with a first electric control valve 73, the heater 72 is connected to a gas collecting bottle 71, the gas collecting bottle 71 is connected to the gas phase space of the vertical storage tank 1 through a gas collecting pipe 70a, the gas collecting pipe 70a is connected to the vent pipe 5 through a three-way stopcock 6, and the two ends of the pressure reducing pipe 100 are respectively connected to the bottom of the vertical storage tank 1. The end and the top of the vertical storage tank 1, a second electric control valve 101 is arranged on the pressure reducing pipe 100, a pressure reducing nozzle 102 is installed at the end of the pressure reducing pipe 100, the upper part of the capacitive liquid level gauge 20 is placed on the flange 7, and the lower part of the capacitive liquid level gauge 20 is placed in the sleeve 60, the sleeve 60 is connected to the rotating slider 8, the rotating slider 8 is connected to the lifting rod 12, the upper end of the lifting rod 12 is connected to the rotating lifting module 30, the starting end of the folding arm 40 is fixed on the lifting rod 12, and the paddle 52 is fixed to the lower end of the outermost arm of the folding arm 40.

[0015] Furthermore, the upper ends of the lifting rods 12 are connected, the interior of the lifting rods 12 is a hollow structure, and a stopper 13 is provided at the end of the lifting rods 12 .

[0016] Further, the folding arm 40 includes a lifting slider 42, a shaft wheel 43, a folding short arm 44, a movable block 45, a connecting arm 46, a fixing screw 47, a folding outer arm 48, and a baffle 49;

[0017] The lifting slider 42 is fixed on the lifting rod 12, the folding short arm 44 is connected to the lifting slider 42 through the shaft wheel 43, the upper end of the folding short arm 44 is connected to the movable block 45, the connecting arm 46 is fixed to the movable block 45 through a fixing screw 47, the fixing screw 47 is connected to the rotating slider 8, the folding outer arm 48 is connected to the connecting arm 46 through a gear structure, the baffle 49 is fixed on the folding outer arm 48, and the folding outer arm 48 and the connecting arm 46 are arranged with a tank parameter monitoring unit;

[0018] Two folding arms 40 are installed on each rotating slider 8 at an angle of 180°. The length of the folding short arm 44 is 1 / 3 of the length of the connecting arm 46 , and the connecting arm 46 is the same length as the folding outer arm 48 .

[0019] Furthermore, the front and rear ends of the paddle 52 are arc-shaped structures, and a space is reserved in the middle for the tank parameter monitoring unit. The thickness of the paddle 52 is smoothly thickened from 3 mm on the outside to 10 mm on the inside.

[0020] Further, the sleeve 60 includes a pair of holes 61 and a fixed circular plate 62;

[0021] The sleeve 60 has holes 61 arranged every 200 mm, and the interior of the sleeve 60 has fixed circular plates 62 arranged every 400 mm.

[0022] Furthermore, the heater 72 includes a heating wire 72a, a perforated plate 72b, a liquid phase tank 72c and a glass cover 72d;

[0023] The orifice plate 72b is installed at 50 mm above the liquid phase tank 72c, the glass cover 72d is installed at 100 mm above the orifice plate 72b, and the heating wire 72a is placed in the glass cover.

[0024] Furthermore, the flange 7 is composed of an outer ring, a rotating ring and an inner ring;

[0025] The rotating ring of the flange 7 is located between the outer ring and the inner ring. The outer ring is fixed to the inner ring. The rotating ring is connected to the outer ring and the inner ring and is sealed by lubricating oil.

[0026] Further, the tank parameter monitoring unit includes a pressure sensor 10, a temperature sensor 11 and a density sensor 51;

[0027] The pressure sensor 10 is arranged at the lower end of the folded outer arm 48, the temperature sensor 11 is arranged at intervals of 150 mm on the connecting arm 46 and the folded outer arm 48, the density sensor 51 is fixed in the middle position of the baffle 49, and the lead wires of the sensor are buried in the hollow structure of the lifting rod 12.

[0028] A method for monitoring and pressure buffering a LNG vertical storage tank comprises the following steps:

[0029] S1: After the monitoring device passes the self-test, the upper computer 4 remotely sends a control signal to the receiving antenna 33 of the rotating lifting module 30, and the lifting motor 31 of the rotating lifting module 30 starts to run and drives the lifting gear 36 to rotate. The rotation of the lifting gear 36 drives the rotating lifting rod 32 to descend, so that the lifting rod 12 descends, and the lifting slider 42 descends together with the lifting rod 12. The folding short arm 44 moves downward to make the movable block 45 flat, and the connecting arm 46 is flat. Due to the action of the gear, the folding outer arm 48 is flat, and the folding arm 40 is fully extended;

[0030] S2: The pressure sensor 10 and the temperature sensor 11 monitor the pressure and temperature of the gas-liquid two-phase in the storage tank after the folding arm 40 is unfolded, and the monitoring data is transmitted to the signal receiver 2 through the lead wire, and the signal receiver 2 collects and processes the electrical signal and transmits it to the host computer 4;

[0031] S3: When the storage tank pressure monitored by the pressure sensor 10 is greater than the set safety pressure of 1Mpa, the host computer 4 remotely sends a control signal to the second electric control valve 101, the second electric control valve 101 is opened, and the LNG in the vertical storage tank 1 is sprayed into the storage tank through the pressure reducing pipe 100 using the pressure reducing nozzle 102 under the action of pressure;

[0032] S4: the density sensor 51 monitors the density of LNG in the storage tank after the folding arm 40 is unfolded, and the monitoring data is transmitted to the signal receiver 2 through the lead wire, and the signal receiver 2 transmits the processed data to the host computer 4;

[0033] S5: The maximum density difference of LNG monitored by the density sensor 51 is greater than the set 2kg / m 3 When the upper computer 4 remotely sends a control signal to the receiving antenna 33 of the rotary lifting module 30, the lifting motor 31 of the rotary lifting module 30 starts to run and drives the rotary gear 35 to rotate, and the rotary gear 35 drives the rotary lifting rod 32 to rotate, so that the lifting rod 12 rotates, and under the action of mutual force, the rotary slider 8 drives the paddle 52 on the folding arm 40 to rotate, stirring the LNG in the vertical storage tank 1;

[0034] S6: The gas collecting pipe 70 allows the gas phase in the vertical storage tank 1 to enter the gas collecting bottle 71 through the three-way stopcock 6, and then the gas in the gas collecting bottle 71 is introduced into the gas chromatograph 3 to detect the LNG evaporation gas components. A small amount of LNG enters the heater 72 through the first electric control valve 73. The heating wire 72a of the heater 72 is electrically heated. After the LNG is completely gasified, it enters the gas collecting bottle 71 and is introduced into the gas chromatograph 3 to complete the detection of the LNG components. The detection results of the gas chromatograph 3 are displayed on the host computer 4;

[0035] S7: The capacitive liquid level meter 20 monitors the liquid level of the storage tank. The LNG contacts the probe 23 of the capacitive liquid level meter 20 through the hole 61 reserved in the sleeve 60. The liquid level changes the capacitance value of the probe 23. The capacitive liquid level sensor 21 receives the capacitance value. The capacitive liquid level sensor 21 exports the capacitance value to the signal receiver 2 through the capacitive lead-out line 22. The signal receiver 2 converts the electrical signal into a numerical signal, and finally displays the liquid level information on the host computer 4.

[0036] The beneficial effects of the invention are:

[0037] (1) The present invention designs a multi-parameter monitoring unit for a storage tank, which monitors the liquid level, liquid phase density, gas-liquid two-phase temperature and pressure, and components in the storage tank through a capacitive liquid level meter, a density sensor, a temperature sensor, a pressure sensor, and a component detection system, thereby improving the monitoring accuracy.

[0038] (2) The present invention designs a pressure buffer unit. Under the action of pressure, LNG is sprayed from the top of the storage tank through a pressure reducing nozzle to reduce the pressure of the storage tank. The blades of the monitoring device rotate to reduce the maximum density difference of LNG and prevent stratification and rolling.

[0039] (3) The present invention is designed with a folding and rotating structure, and the monitoring unit is retracted into the main shaft of the monitoring device. The installation of the device has little effect on the modification of the storage tank, thereby increasing the service life of the storage tank and ensuring the safe operation of the storage tank. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a schematic diagram of the structure of the LNG vertical storage tank monitoring and pressure buffer device in an embodiment of the present invention.

[0041] Figure 2 Schematic diagram of the structure of the folding arm in an embodiment of the present invention.

[0042] Figure 3 It is a cross-sectional view of the structure of the rotary slider and the folding arm in the embodiment of the present invention when they are retracted.

[0043] Figure 4 It is a cross-sectional view of the structure of the rotating slider and the folding arm in the embodiment of the present invention when they are unfolded.

[0044] Figure 5 It is a schematic diagram of the installation of the sleeve and the capacitive liquid level gauge in the embodiment of the present invention.

[0045] Figure 6 Schematic diagram of the heater structure in an embodiment of the present invention.

[0046] Figure 7 It is a schematic diagram of the structure of the lifting module in an embodiment of the present invention.

[0047] Figure 8 It is a working flow chart of the LNG vertical storage tank monitoring and pressure buffer device in an embodiment of the present invention. DETAILED DESCRIPTION

[0048] The specific implementation modes of the present invention are described below in conjunction with the accompanying drawings for better understanding of the present invention.

[0049] Example

[0050] In this embodiment, Figure 1 It is a structural schematic diagram of an LNG vertical storage tank monitoring and pressure buffer device, which includes a vertical storage tank 1, a signal collection system 2, a gas chromatograph 3, a host computer 4, a vent pipe 5, a three-way plug valve 6, a flange 7, a rotating slider 8, a fixed plywood 9, a pressure sensor 10, a temperature sensor 11, a lifting rod 12, a stopper 13, a capacitive level gauge 20, a rotating lifting module 30, a folding arm 40, a density sensor 51, a paddle 52, a sleeve 60, a gas collection pipe 70, a gas collection bottle 71, a heater 72, a first electric control valve 73, a pressure reducing pipe 100, a second electric control valve 101, and a pressure reducing nozzle 102;

[0051] The top of the vertical storage tank 1 is reserved with an opening, the monitoring device is installed inside the vertical storage tank 1 through a flange 7, the bottom of the vertical storage tank 1 is connected to the heater 72 through a gas collecting pipe 70b, the gas collecting pipe 70b is installed with a first electric control valve 73, the heater 72 is connected to a gas collecting bottle 71, the gas collecting bottle 71 is connected to the gas phase space of the vertical storage tank 1 through a gas collecting pipe 70a, the gas collecting pipe 70a is connected to the vent pipe 5 through a three-way stopcock 6, and the two ends of the pressure reducing pipe 100 are respectively connected to the bottom of the vertical storage tank 1. The end and the top of the vertical storage tank 1, the second electric control valve 101 is arranged on the pressure reducing pipe 100, the pressure reducing nozzle 102 is installed at the end of the pressure reducing pipe 100, the upper part of the capacitive liquid level gauge 20 is placed on the flange 7, the lower part of the capacitive liquid level gauge 20 is placed in the sleeve 60, the sleeve 60 is connected to the rotating slider 8, the rotating slider 8 is connected to the lifting rod 12, the upper end of the lifting rod 12 is connected to the rotating lifting module 30, the starting end of the folding arm 40 is fixed on the lifting rod 12, and the paddle 52 is fixed to the lower end of the outermost arm of the folding arm 40;

[0052] The upper ends of the lifting rods 12 are connected, the interior of the lifting rods 12 is a hollow structure, and a stopper 13 is provided at the end of the lifting rods 12 .

[0053] Figure 2 It is a structural schematic diagram of a folding arm, including a lifting slider 42, a shaft wheel 43, a folding short arm 44, a movable block 45, a connecting arm 46, a fixing screw 47, a folding outer arm 48, a baffle 49, a density sensor 51, a pressure sensor 10, and a temperature sensor 11;

[0054] The lifting slider 42 is fixed on the lifting rod 12, the folding short arm 44 is connected to the lifting slider 42 through the shaft wheel 43, the upper end of the folding short arm 44 is connected to the movable block 45, the connecting arm 46 is fixed to the movable block 45 through a fixing screw 47, the fixing screw 47 is connected to the rotating slider 8, the folding outer arm 48 is connected to the connecting arm 46 through a gear structure, the baffle 49 is fixed on the folding outer arm 48, and the folding outer arm 48 and the connecting arm 46 are arranged with a tank parameter monitoring unit;

[0055] Two folding arms 40 are installed on each rotating slider 8 at an angle of 180°. The length of the folding short arm 44 is 1 / 3 of the length of the connecting arm 46 , and the connecting arm 46 is the same length as the folding outer arm 48 .

[0056] Figure 3 This is a cross-sectional view of the structure with the rotating slider and folding arm retracted. Figure 4 It is a cross-sectional view of the structure of the rotating slider and the folding arm, including the rotating slider 8, the pressure sensor 10, the temperature sensor 11, the lifting rod 12, the probe 23, the folding arm 40, the density sensor 51, the paddle 52, the sleeve 60, the hole 61, and the fixed original plate 62;

[0057] The front and rear ends of the paddle 52 are arc-shaped structures, and the middle is reserved for the tank parameter monitoring unit. The thickness of the paddle 52 is smoothly thickened from 3mm on the outside to 10mm on the inside.

[0058] The pressure sensor 10 is arranged at the lower end of the folded outer arm 48, the temperature sensor 11 is arranged at intervals of 150 mm on the connecting arm 46 and the folded outer arm 48, the density sensor 51 is fixed in the middle position of the baffle 49, and the lead wires of the sensor are buried in the hollow structure of the lifting rod 12.

[0059] Figure 5 It is a schematic diagram of the installation of the sleeve and the capacitive liquid level gauge, including a flange 7, a capacitive liquid level gauge sensor 21, a capacitive liquid level gauge lead wire 22, a probe 23, a sleeve 60, a matching hole 61, and a fixing original plate 62;

[0060] The sleeve 60 is provided with holes 61 every 200 mm, and the interior of the sleeve 60 is provided with fixed circular plates 62 every 400 mm;

[0061] The rotating ring of the flange 7 is located between the outer ring and the inner ring. The outer ring is fixed to the inner ring. The rotating ring is connected to the outer ring and the inner ring and is sealed by lubricating oil.

[0062] Figure 6 Schematic diagram of the heater structure, including a heating wire 72a, a perforated plate 72b, a liquid phase tank 72c and a glass cover 72d;

[0063] The orifice plate 72b is installed at 50 mm above the liquid phase tank 72c, the glass cover 72d is installed at 100 mm above the orifice plate 72b, and the heating wire 72a is placed in the glass cover.

[0064] Figure 7 It is a schematic diagram of the lifting module structure, including a lifting motor 31, a rotating lifting rod 32, a receiving antenna 33, a motor gear 34, a rotating gear 35, a lifting gear 36, and a lifting rod 12.

[0065] Figure 8 This is the working flow chart of the LNG vertical storage tank monitoring and pressure buffer device. First, the monitoring and buffer equipment is installed on the storage tank. The monitoring equipment is clamped on the vertical storage tank 1 through the flange 7. The upper computer 4 remote control device is turned on and completes the self-test. After the self-test is completed, the folding structure is unfolded to monitor the liquid level, LNG density, gas-liquid two-phase temperature and pressure, and components in the storage tank. The signal is transmitted to the upper computer 4 through the signal receiver 2. The density difference and pressure are determined according to the monitored data, and the spraying pressure reduction and blade rotation are performed to reduce the LNG density difference.

[0066] A method for monitoring and pressure buffering a LNG vertical storage tank comprises the following steps:

[0067] S1: After the monitoring device passes the self-test, the upper computer 4 remotely sends a control signal to the receiving antenna 33 of the rotating lifting module 30, and the lifting motor 31 of the rotating lifting module 30 starts to run and drives the lifting gear 36 to rotate. The rotation of the lifting gear 36 drives the rotating lifting rod 32 to descend, so that the lifting rod 12 descends, and the lifting slider 42 descends together with the lifting rod 12. The folding short arm 44 moves downward to make the movable block 45 flat, and the connecting arm 46 is flat. Due to the action of the gear, the folding outer arm 48 is flat, and the folding arm 40 is fully extended;

[0068] S2: The pressure sensor 10 and the temperature sensor 11 monitor the pressure and temperature of the gas-liquid two-phase in the storage tank after the folding arm 40 is unfolded, and the monitoring data is transmitted to the signal receiver 2 through the lead wire, and the signal receiver 2 collects and processes the electrical signal and transmits it to the host computer 4;

[0069] S3: When the storage tank pressure monitored by the pressure sensor 10 is greater than the set safety pressure of 1Mpa, the host computer 4 remotely sends a control signal to the second electric control valve 101, the second electric control valve 101 is opened, and the LNG in the vertical storage tank 1 is sprayed into the storage tank through the pressure reducing pipe 100 using the pressure reducing nozzle 102 under the action of pressure;

[0070] S4: the density sensor 51 monitors the density of LNG in the storage tank after the folding arm 40 is unfolded, and the monitoring data is transmitted to the signal receiver 2 through the lead wire, and the signal receiver 2 transmits the processed data to the host computer 4;

[0071] S5: The maximum density difference of LNG monitored by the density sensor 51 is greater than the set 2kg / m 3 When the upper computer 4 remotely sends a control signal to the receiving antenna 33 of the rotary lifting module 30, the lifting motor 31 of the rotary lifting module 30 starts to run and drives the rotary gear 35 to rotate, and the rotary gear 35 drives the rotary lifting rod 32 to rotate, so that the lifting rod 12 rotates, and under the action of mutual force, the rotary slider 8 drives the paddle 52 on the folding arm 40 to rotate, stirring the LNG in the vertical storage tank 1;

[0072] S6: The gas collecting pipe 70 allows the gas phase in the vertical storage tank 1 to enter the gas collecting bottle 71 through the three-way stopcock 6, and then the gas in the gas collecting bottle 71 is introduced into the gas chromatograph 3 to detect the LNG evaporation gas components. A small amount of LNG enters the heater 72 through the first electric control valve 73. The heating wire 72a of the heater 72 is electrically heated. After the LNG is completely gasified, it enters the gas collecting bottle 71 and is introduced into the gas chromatograph 3 to complete the detection of the LNG components. The detection results of the gas chromatograph 3 are displayed on the host computer 4;

[0073] S7: The capacitive liquid level meter 20 monitors the liquid level of the storage tank. The LNG contacts the probe 23 of the capacitive liquid level meter 20 through the hole 61 reserved in the sleeve 60. The liquid level changes the capacitance value of the probe 23. The capacitive liquid level sensor 21 receives the capacitance value. The capacitive liquid level sensor 21 exports the capacitance value to the signal receiver 2 through the capacitive lead-out line 22. The signal receiver 2 converts the electrical signal into a numerical signal, and finally displays the liquid level information on the host computer 4.

[0074] The above is a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. An LNG vertical storage tank monitoring and pressure buffer device, characterized in that: It comprises a vertical storage tank (1), a three-way stopcock (6), a flange (7), a rotating slider (8), a capacitive liquid level gauge (20), a rotating lifting module (30), a folding arm (40), a lifting rod (12), a paddle (52), a sleeve (60), a gas collection pipe (70), a gas collection bottle (71), a heater (72), a first electric control valve (73), a pressure reducing pipe (100), a second electric control valve (101), and a pressure reducing nozzle (102); The top of the vertical storage tank (1) is reserved with an opening, the monitoring device is installed inside the vertical storage tank (1) via a flange (7), the bottom of the vertical storage tank (1) is connected to the heater (72) via a gas collection pipe (70b), the gas collection pipe (70b) is installed with a first electric control valve (73), the heater (72) is connected to a gas collection bottle (71), the gas collection bottle (71) is connected to the gas phase space of the vertical storage tank (1) via a gas collection pipe (70a), the gas collection pipe (70a) is connected to the vent pipe (5) via a three-way stopcock (6), and the two ends of the pressure reducing pipe (100) are respectively connected to the bottom of the vertical storage tank (1). and the top of the vertical storage tank (1), a second electric control valve (101) is arranged on the pressure reducing pipe (100), a pressure reducing nozzle (102) is installed at the end of the pressure reducing pipe (100), the upper part of the capacitive liquid level gauge (20) is placed on the flange (7), the lower part of the capacitive liquid level gauge (20) is placed in the sleeve (60), the sleeve (60) is connected to the rotating slider (8), the rotating slider (8) is connected to the lifting rod (12), the upper end of the lifting rod (12) is connected to the rotating lifting module (30), the starting end of the folding arm (40) is fixed on the lifting rod (12), and the paddle (52) is fixed to the lower end of the outermost arm of the folding arm (40).

2. The LNG vertical storage tank monitoring and pressure buffer device according to claim 1 is characterized in that: The upper ends of the lifting rods (12) are connected, the interior of the lifting rods (12) is a hollow structure, and a stopper (13) is provided at the end of the lifting rods (12).

3. The LNG vertical storage tank monitoring and pressure buffer device according to claim 1 is characterized in that: The folding arm (40) comprises a lifting slider (42), a shaft wheel (43), a folding short arm (44), a movable block (45), a connecting arm (46), a fixing screw (47), a folding outer arm (48), and a baffle (49); The lifting slider (42) is fixed on the lifting rod (12), the folding short arm (44) is connected to the lifting slider (42) through a shaft wheel (43), the upper end of the folding short arm (44) is connected to the movable block (45), the connecting arm (46) is fixed to the movable block (45) through a fixing screw (47), the fixing screw (47) is connected to the rotating slider (8), the folding outer arm (48) is connected to the connecting arm (46) through a gear structure, the baffle (49) is fixed on the folding outer arm (48), and the folding outer arm (48) and the connecting arm (46) are arranged with a tank parameter monitoring unit; Two folding arms (40) are installed on each rotating slider (8) at an angle of 180 degrees. The length of the folding short arm (44) is 1 / 3 of the length of the connecting arm (46). The connecting arm (46) is the same length as the folding outer arm (48).

4. The LNG vertical storage tank monitoring and pressure buffer device according to claim 1 is characterized in that: The front and rear ends of the paddle (52) are arc-shaped structures, and a space is reserved in the middle for a storage tank parameter monitoring unit. The thickness of the paddle (52) is smoothly thickened from 3 mm on the outside to 10 mm on the inside.

5. The LNG vertical storage tank monitoring and pressure buffer device according to claim 1 is characterized in that: The sleeve (60) comprises a counter hole (61) and a fixed circular plate (62); The sleeve (60) is provided with matching holes (61) every 200 mm, and a fixed circular plate (62) is arranged inside the sleeve (60) every 400 mm.

6. The LNG vertical storage tank monitoring and pressure buffer device according to claim 1 is characterized in that: The heater (72) comprises a heating wire (72a), a perforated plate (72b), a liquid phase tank (72c) and a glass cover (72d); The orifice plate (72b) is installed at 50 mm on the liquid phase tank (72c), the glass cover (72d) is installed at 100 mm on the orifice plate (72b), and the heating wire (72a) is placed in the glass cover; The heating wire (72a) has three temperature levels, which heat the heating wire (72a) to 80°C, 130°C, and 180°C respectively.

7. The LNG vertical storage tank monitoring and pressure buffer device according to claim 1 is characterized in that: The flange (7) is composed of an outer ring, a rotating ring and an inner ring; The rotating ring of the flange (7) is located between the outer ring and the inner ring, the outer ring is fixed to the inner ring, and the rotating ring is connected to the outer ring and the inner ring and is sealed by lubricating oil.

8. The LNG vertical storage tank monitoring and pressure buffer device according to claim 3 is characterized in that: The storage tank parameter monitoring unit comprises a pressure sensor (10), a temperature sensor (11) and a density sensor (51); The pressure sensor (10) is arranged at the lower end of the folded outer arm (48), the temperature sensor (11) is arranged at intervals of 150 mm at the upper ends of the connecting arm (46) and the folded outer arm (48), the density sensor (51) is fixed at the middle position of the baffle (49), and the lead wire of the sensor is arranged through the hollow structure embedded in the lifting rod (12).

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