Low-temperature LNG unloading pry

Abstract

The utility model belongs to the technical field of unloading pry, and discloses a low-temperature LNG unloading pry, which has the specific technical scheme that the low-temperature LNG unloading pry comprises a torch emptying pipeline, a gas phase balance pipeline, a liquid phase pipeline and a nitrogen purging pipeline, and the gas phase pipeline is connected with a gas phase arm through a pneumatic stop valve, a pressure transmitter and a stop valve; the gas phase balance pipeline is communicated with a torch emptying pipeline through a second safety valve; the liquid-phase pipeline is connected with a liquid-phase arm through a stop valve, a temperature transmitter, a pressure transmitter, a pneumatic stop valve check valve, a filter and a low-temperature unloading pump; the liquid-phase pipeline is communicated with a torch emptying pipeline through a first safety valve and a third safety valve; the nitrogen purging pipeline is communicated with the rotary joint through a stop valve, a pressure reducing valve and a check valve; the unloading pressurizing pipeline is communicated with a gas phase through an unloading pressurizer and a stop valve; after unloading is started, the unloading control instrument receives analog signals transmitted by the pressure gauge transmitter and the temperature transmitter and controls the unloading pump to be started according to data of the temperature transmitter and the pressure transmitter.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of unloading sleds, and particularly relates to an LNG unloading sled. BACKGROUND

[0002] With the rapid development of China's economy, the demand for clean energy is increasing, LNG exists in the form of liquid natural gas, which not only facilitates the transportation and storage of natural gas, but also promotes the trade of natural gas and the development of natural gas application. In recent decades, the liquefied natural gas industry has become a new industry and has developed rapidly. The LNG industry is a new industry, which not only develops rapidly, but also progresses significantly. In order to adapt to the development situation of the LNG industry, there has been significant progress in the liquefaction, storage, transportation and other aspects of the LNG industry chain.

[0003] The production devices of large and medium-sized petrochemical chemical enterprises in China have backward manual operation, low automation degree and prominent safety hazards. In recent years, dangerous chemical leakage and explosion accidents have occurred frequently in chemical plants, and the State Emergency Management Department has put forward strict control and requirements for the safety production and automation of dangerous chemical enterprises. Since the medium LNG is flammable and explosive, manual unloading has low efficiency and high loss, manual operation is easy to overlook that the static grounding may not be firm or forget to connect the static clamp, and there is a safety hazard of static electricity accumulation at any time during the unloading process. In order to overcome the disadvantages brought by manual operation and management, improve the efficiency of on-site operation and management and the overall benefit of the chemical enterprise, and meet the needs of economic development, it is urgent to develop an automatic unloading system with high automation degree, good safety reliability and convenient operation and maintenance. CONTENT OF THE UTILITY MODEL

[0004] In order to solve the technical problems existing in the prior art, the utility model provides an LNG unloading sled, which is suitable for automobile unloading, pressure pipeline and overall sled equipment of LNG, and realizes automatic and safe unloading of LNG.

[0005] In order to achieve the above-mentioned purpose, the utility model adopts the technical scheme of a low-temperature LNG unloading sled, which comprises a torch venting pipeline, a gas phase balance pipeline, a liquid phase pipeline and a nitrogen pipeline.

[0006] The torch venting pipeline is connected with the first safety valve and the liquid phase pipeline through the first venting pipeline, and releases the excess combustible gas in the front section of the liquid phase pipeline through the control of the first safety valve; the torch venting pipeline is connected with the second safety valve and the gas phase balance pipeline through the second venting pipeline, and releases the excess combustible gas in the gas phase balance pipeline through the control of the second safety valve; the torch venting pipeline is connected with the third safety valve and the liquid phase pipeline through the third venting pipeline, and releases the excess combustible gas in the rear section of the liquid phase pipeline through the control of the third safety valve.

[0007] A gas phase shut-off valve is installed on the gas phase balance pipeline. The gas phase shut-off valve is connected to the gas phase stop valve and the gas phase arm through a pipeline. A gas phase break valve is installed on the output end of the gas phase arm. The gas phase shut-off valve, the gas phase stop valve, and the gas phase break valve control the opening, closing, and operation of the entire gas phase balance pipeline. A gas phase pressure transmitter is installed on the gas phase balance pipeline to monitor the gas pressure in the gas phase balance pipeline.

[0008] The liquid phase pipeline is equipped with a liquid phase shut-off valve, which is connected to one end of the unloading pump via a pipeline and a liquid phase check valve. The other end of the unloading pump is connected to a liquid phase shut-off valve, a filter, a liquid phase arm, and a liquid phase disconnect valve via pipelines. The liquid phase shut-off valve and the liquid phase check valve control the opening, closing, and operation of the entire liquid phase pipeline. The liquid phase pipeline is equipped with a liquid phase pressure transmitter and a liquid phase temperature transmitter. The liquid phase pressure transmitter monitors the pressure in the liquid phase pipeline, and the liquid phase temperature transmitter monitors the temperature in the liquid phase pipeline.

[0009] The nitrogen pipeline is equipped with a nitrogen shut-off valve, which is connected to the inlet of a nitrogen check valve via a pipeline. The outlet of the nitrogen check valve is connected to a pressure reducing valve and a rotary joint via a first branch pipeline. The outlet of the nitrogen check valve is connected to the output of the gas phase arm via a second branch pipeline. The outlet of the nitrogen check valve is connected to the output of the liquid phase arm via a third branch pipeline. The nitrogen check valve controls the opening and closing of the entire nitrogen pipeline, and the pressure reducing valve is used to reduce the gas pressure in the nitrogen pipeline.

[0010] A safety line is installed on the liquid phase pipeline. The safety line is connected in parallel to both ends of the unloading pump and is equipped with a safety shut-off valve. As an auxiliary line, the safety line can release pressure in time when the unloading pump fails.

[0011] The first and third safety valves are located on opposite sides of the unloading pump to ensure the safe operation of the entire liquid phase pipeline, both upstream and downstream.

[0012] The flare vent line is connected to the output end of the liquid phase arm through the fourth vent pipe, which is located between the liquid phase arm and the liquid phase disconnect valve. The fourth vent pipe is used to release excess gas at the front end of the liquid phase arm.

[0013] This utility model also includes an unloading pressurization pipeline, which is equipped with an unloading pressurizer. One end of the unloading pressurizer is connected to an unloading check valve via a pipeline, and the other end is connected to an unloading safety valve and a flare venting pipeline via a first unloading branch. The remaining end of the unloading pressurizer is connected to an unloading shut-off valve and a gas phase balance pipeline via a second unloading branch. The unloading pressurizer converts liquid LNG into gas, which then enters the tank truck through the gas phase balance pipeline, increasing the pressure at the top of the gas phase in the tank truck.

[0014] The utility model also includes unloading control appearance, unloading control appearance is connected with audible -visual alarm, on -the -spot emergency stop button, gas phase emergency cut -out valve, reserved communication interface, anti -static controller, anti -static controller is connected with static grounding clamp, unloading control appearance and gas phase cut -out valve, gas phase pressure transmitter's signal end intercommunication, unloading one and liquid phase cut -out valve, liquid phase pressure transmitter's signal end intercommunication.

[0015] The utility model discloses compared with prior art, specific beneficial effect reflects in: pry dress formula liquid unloading device is equipped with by the on -the -spot anti -explosion unloading control appearance, emergency cut -out valve, static overflow protection system, unloading crane pipe, upper management system etc., constitutes a complete distributed system, and the whole system adopts distributed networking structure, and the unloading control appearance communication of operation station and on -the -spot, realizes the whole system monitoring management concentration, and the purpose of control risk dispersion, guarantees system safety, environmental protection, reliable, efficient operation.

[0016] Pry dress formula liquid unloading device has two control modes of independent control and remote control, wherein the unloading control appearance can carry out program control, static interlock control to unloading process, and the unloading control appearance adopts anti -explosion type with explosion -proof IC card formula structure, and is installed on the crane position side of unloading platform to run as a single machine, and operating personnel can carry out all setting, on -the -spot operation and monitor unloading process working condition etc. BRIEF DESCRIPTION OF DRAWINGS

[0017] Fig. 1 It is the structural schematic diagram of the utility model.

[0018] Fig. 2 It is the control principle diagram of unloading control appearance.

[0019] In the diagram, 1 is the flare vent line, 11 is the first vent pipe, 12 is the first safety valve, 13 is the second vent pipe, 14 is the second safety valve, 15 is the third vent pipe, 16 is the third safety valve, 17 is the fourth vent pipe, 2 is the gas phase balance line, 21 is the gas phase shut-off valve, 22 is the gas phase stop valve, 23 is the gas phase arm, 24 is the gas phase break-off valve, 25 is the gas phase pressure transmitter, 3 is the liquid phase line, 31 is the liquid phase shut-off valve, 32 is the liquid phase check valve, 33 is the unloading pump, 34 is the liquid phase stop valve, 35 is the filter, 36 is the liquid phase arm, 37 is the liquid phase break-off valve, 38 is the liquid phase pressure transmitter, and 39 is the liquid phase pressure transmitter. 9 is a liquid phase temperature transmitter, 4 is a nitrogen pipeline, 41 is a nitrogen shut-off valve, 42 is a nitrogen check valve, 43 is the first branch pipeline, 44 is a pressure reducing valve, 45 is a rotary joint, 46 is the second branch pipeline, 47 is the third branch pipeline, 5 is a safety shut-off valve, 6 is an unloading pressurization pipeline, 61 is an unloading pressurizer, 62 is an unloading check valve, 63 is the first unloading branch, 64 is an unloading safety valve, 65 is the second unloading branch, 66 is an unloading shut-off valve, 7 is an unloading controller, 71 is an audible and visual alarm, 72 is an on-site emergency stop button, 73 is a reserved communication interface, 74 is an anti-static controller, and 75 is an anti-static grounding clamp. Detailed Implementation

[0020] To make the technical problems, technical solutions, and beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0021] like Figs. 1-2 As shown, a cryogenic LNG unloading skid includes a flare vent line 1, a gas phase balance line 2, a liquid phase line 3, and a nitrogen line 4.

[0022] Flare vent line 1 is connected to the first safety valve 12 and the liquid phase line 3 via the first vent pipe 11. Under the control of the first safety valve 12, flare vent line 1 releases excess combustible gas in the front section of the liquid phase line 3. Flare vent line 1 is connected to the second safety valve 14 and the gas phase balance line 2 via the second vent pipe 13. Under the control of the second safety valve 14, flare vent line 1 releases excess combustible gas in the gas phase balance line 2. Flare vent line 1 is connected to the third safety valve 16 and the liquid phase line 3 via the third vent pipe 15. Under the control of the third safety valve 16, flare vent line 1 releases excess combustible gas in the rear section of the liquid phase line 3.

[0023] The gas phase balance pipeline 2 is provided with a gas phase cut-off valve 21, which is connected with a gas phase stop valve 22 and a gas phase arm 23 through pipelines, and the output end of the gas phase arm 23 is provided with a gas phase pull-off valve 24. The opening and closing and operation of the entire gas phase balance pipeline 2 are controlled through the gas phase cut-off valve 21, the gas phase stop valve 22 and the gas phase pull-off valve 24. The gas phase balance pipeline 2 is provided with a gas phase pressure transmitter 25, which is used to monitor the gas pressure in the gas phase balance pipeline 2.

[0024] The liquid phase pipeline 3 is provided with a liquid phase cut-off valve 31, which is connected with a liquid phase check valve 32 and one end of a pump 33 through pipelines. The other end of the pump 33 is connected with a liquid phase stop valve 34, a filter 35, a liquid phase arm 36 and a liquid phase pull-off valve 37 through pipelines. The opening and closing and operation of the entire liquid phase pipeline 3 are controlled through the liquid phase cut-off valve 31 and the liquid phase check valve 32. The liquid phase pipeline 3 is provided with a liquid phase pressure transmitter 38 and a liquid phase temperature transmitter 39. The liquid phase pressure transmitter 38 is used to monitor the pressure in the liquid phase pipeline 3, and the liquid phase temperature transmitter 39 is used to monitor the temperature in the liquid phase pipeline 3.

[0025] The nitrogen pipeline 4 is provided with a nitrogen stop valve 41, which is connected with an inlet end of a nitrogen check valve 42 through a pipeline. The outlet end of the nitrogen check valve 42 is connected with a pressure reducing valve 44 and a rotary joint 45 through a first branch pipeline 43. The outlet end of the nitrogen check valve 42 is connected with the output end of the gas phase arm 23 through a second branch pipeline 46. The outlet end of the nitrogen check valve 42 is connected with the output end of the liquid phase arm 36 through a third branch pipeline 47. The nitrogen check valve 42 controls the opening and closing of the entire nitrogen pipeline 4. The pressure reducing valve 44 is used to reduce the gas pressure in the nitrogen pipeline 4.

[0026] The liquid phase pipeline 3 is provided with a safety pipeline, which is connected in parallel with the two ends of the pump 33. The safety pipeline is provided with a safety stop valve 5. The safety pipeline serves as an auxiliary pipeline, and can timely release pressure when the pump 33 fails.

[0027] The first safety valve 12 and the third safety valve 16 are arranged on the two sides of the pump 33, so as to ensure the safe operation of the front section and the rear section of the entire liquid phase pipeline 3.

[0028] The torch vent pipeline 1 is connected with the output end of the liquid phase arm 36 through a fourth vent pipeline 17, which is arranged between the liquid phase arm 36 and the liquid phase pull-off valve 37. The fourth vent pipeline 17 is used to release the excess gas at the front end of the liquid phase arm 36.

[0029] The utility model also includes unloading booster pipeline 6, shows unloading booster pipeline 6 is equipped with unloading booster 61, and one end of unloading booster 61 is communicated with unloading check valve 62 through pipeline, and the other end of unloading booster 61 is communicated with unloading safety valve 64, torch vent pipeline 1 through first unloading branch 63, and the other end of unloading booster 61 is communicated with unloading stop valve 66, gas phase balance pipeline 2 through second unloading branch 65.

[0030] The utility model also includes unloading control instrument 7, and unloading control instrument 7 is electrically connected with audible and visual alarm 71, field emergency stop button 72, gas phase emergency cut-off valve, reserved communication interface 73, anti-static controller 74, and anti-static controller 74 is connected with static grounding clamp 75, and unloading control instrument 7 is communicated with the signal end of gas phase cut-off valve 21, gas phase pressure transmitter 25, and the signal end of unloading one is communicated with liquid phase cut-off valve 31, liquid phase pressure transmitter 38. The whole system adopts distributed networking structure, and unloading control instrument 7 of operation station and field communicates, and the whole system monitoring management is centralized, and the purpose of control risk dispersion is implemented, and the safe, environmental protection, reliable, efficient operation of system is guaranteed.

[0031] Unloading control instrument 7 detects the grounding condition of tank car through grounding detection system, and immediately outputs alarm signal after the loop resistance between tank car and grounding pile exceeds the specified resistance value, enters unloading control instrument 7 interlock, and audible and visual alarm 71 sends audible and visual alarm signal, so that field personnel can understand the system working condition in time.

[0032] The pry-mounted liquid unloading device is matched by field anti-explosion unloading control instrument 7, unloading control valve, static protection system, unloading crane pipe and upper management system, and constitutes a complete distributed system. The whole system adopts distributed networking structure, and unloading control instrument 7 of operation station and field communicates. The whole system monitoring management is centralized, and the purpose of control risk dispersion is implemented, and the safe, environmental protection, reliable, efficient operation of system is guaranteed.

[0033] The pry-mounted liquid unloading device has two control modes of independent control and remote control, wherein unloading control instrument 7 can carry out program control and static interlock control on the unloading process; unloading control instrument 7 adopts anti-explosion IC card type structure with explosion-proof, is installed on the crane position side of unloading platform to operate as a single machine, and operating personnel can set, operate and monitor the unloading process conditions on site; meanwhile, unloading control instrument 7 is connected with upper system through communication line, and remote control operation, monitoring and other related management can be carried out, so that the centralized management of loading business is realized.

[0034] Process requirements when unloading: LNG unloading needs pre-cooling to prevent the pipe and components from being damaged due to excessive thermal stress, and the temperature reduction rate in the pipe during pre-cooling should not exceed 10℃ / min.

[0035] Unloading booster pipeline 6: during unloading, the unloading booster pipeline 6 converts the liquid LNG from the tank truck into gas through the unloading booster 61, and the general gas phase pipeline enters the tank truck, thereby increasing the pressure at the top of the gas phase of the tank truck; then the LNG in the tank truck enters the storage tank under the dual action of the increased gas phase pressure and the unloading pump 33.

[0036] The specific role of the flare venting pipeline 1 is to release the pressure in the system (such as the gas discharged by the safety valve) on the one hand, and to collect the pipeline sweeping medium on the other hand.

[0037] The specific role of the nitrogen pipeline 4 is to sweep the unloading skid and the unloading arm pipeline, and to sweep the rotary joint. The pipeline is provided with a pressure regulating valve and a rotor flowmeter, and the pressure is swept according to the needs of each pipeline.

[0038] Instrument air pipeline: the instrument air pipeline provides industrial compressed air for the pneumatic actuator, and the design pressure is 1.0Mpa.

[0039] The specific loading steps of the unloading skid are as follows:

[0040] Step one: the LNG tank truck is in place, the ground wire is connected, and the LNG unloading booster hose, the unloading gas phase pipe and the unloading liquid phase pipe are connected.

[0041] Step two: open the unloading booster 61 of the tank truck, the unloading booster 61 inlet valve, and the tank truck booster gas phase valve.

[0042] Step three: when the frost is formed on the discharge valve, close the unloading booster 61 front discharge valve.

[0043] Step four: start the LNG unloading booster 61 to increase the pressure of the LNG tank truck to 0.55Mpa.

[0044] Step five: notify the tank truck driver to open the LNG tank truck liquid inlet valve, open the LNG tank inlet valve, the liquid inlet pipe emergency shut-off valve, the liquid inlet total valve on the LNG storage tank, start the unloading pump 33, and open the LNG storage tank inlet process, pre-cool the storage tank inlet pipeline, and slowly charge the LNG into the storage tank.

[0045] Step six: after the pressure of the LNG storage tank no longer increases, open the LNG storage tank lower liquid inlet valve, slowly increase the charging speed of the LNG storage tank, and pay attention to the changes of the pressure and the liquid level.

[0046] Step seven, after the LNG in the LNG tank truck is unloaded, the LNG tank lower inlet valve is closed, the LNG tank upper inlet valve is opened, and the LNG in the LNG tank truck is used to purge the LNG in the pipeline to the LNG tank.

[0047] Step eight, the tank inlet valve is closed, the gas-liquid balance valve is opened, the pressure of the unloading pipeline is released to the BOG system through the gas phase line, when the gas phase in the tank truck cannot be unloaded, the LNG tank truck inlet valve is closed, the front end vent valve is opened, the LNG gas phase in the LNG tank truck is vented, the gas-liquid valve is opened, and the pressure is balanced and then closed.

[0048] The above only describes the preferred embodiments of the present application, and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the scope of the present application.

Claims

1. A cryogenic LNG unloading sled, comprising: The torch venting pipeline (1), the gas phase balance pipeline (2), the liquid phase pipeline (3) and the nitrogen pipeline (4) are included. The torch venting pipeline (1) is connected with the first safety valve (12) and the liquid phase pipeline (3) through the first venting pipeline (11), the torch venting pipeline (1) is connected with the second safety valve (14) and the gas phase balance pipeline (2) through the second venting pipeline (13), and the torch venting pipeline (1) is connected with the third safety valve (16) and the liquid phase pipeline (3) through the third venting pipeline (15). The gas phase balance pipeline (2) is provided with a gas phase cut-off valve (21), the gas phase cut-off valve (21) is connected with a gas phase stop valve (22) and a gas phase arm (23) through pipelines, the output end of the gas phase arm (23) is provided with a gas phase pull-off valve (24), and the gas phase balance pipeline (2) is provided with a gas phase pressure transmitter (25). The liquid phase pipeline (3) is provided with a liquid phase cut-off valve (31), the liquid phase cut-off valve (31) is connected with a liquid phase check valve (32) and one end of a car unloading pump (33) through pipelines, the other end of the car unloading pump (33) is connected with a liquid phase stop valve (34), a filter (35), a liquid phase arm (36) and a liquid phase pull-off valve (37) through pipelines, and the liquid phase pipeline (3) is provided with a liquid phase pressure transmitter (38) and a liquid phase temperature transmitter (39). The nitrogen pipeline (4) is provided with a nitrogen stop valve (41), the nitrogen stop valve (41) is connected with an air inlet end of a nitrogen check valve (42) through a pipeline, an air outlet end of the nitrogen check valve (42) is connected with a pressure reducing valve (44) and a rotary joint (45) through a first branch pipeline (43), the air outlet end of the nitrogen check valve (42) is connected with an output end of the gas phase arm (23) through a second branch pipeline (46), and the air outlet end of the nitrogen check valve (42) is connected with an output end of the liquid phase arm (36) through a third branch pipeline (47).

2. A cryogenic LNG unloading pry according to claim 1, wherein, A safety pipeline is arranged on the liquid phase pipeline (3), the safety pipeline is connected in parallel at both ends of the car unloading pump (33), and the safety pipeline is provided with a safety stop valve (5).

3. A cryogenic LNG unloading pry according to claim 1, wherein, The first safety valve (12) and the third safety valve (16) are arranged on the two sides of the car unloading pump (33).

4. A cryogenic LNG unloading pry according to claim 1, wherein, The torch venting pipeline (1) is connected with the output end of the liquid phase arm (36) through a fourth venting pipeline (17), and the fourth venting pipeline (17) is arranged between the liquid phase arm (36) and the liquid phase pull-off valve (37).

5. A cryogenic LNG unloading pry according to claim 1, wherein, A car unloading booster pipeline (6) is further included, the car unloading booster pipeline (6) is provided with a car unloading booster (61), one end of the car unloading booster (61) is connected with a car unloading check valve (62) through a pipeline, the other end of the car unloading booster (61) is connected with a car unloading safety valve (64) and the torch venting pipeline (1) through a first car unloading branch (63), and the other end of the car unloading booster (61) is connected with a car unloading stop valve (66) and the gas phase balance pipeline (2) through a second car unloading branch (65).

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