Tank car operation box control system and method for LNG loading and unloading place

Abstract

The invention discloses a tank car operation box control system and method for an LNG loading and unloading place. The tank car operation box control system comprises a tank body; the liquid phase pipeline is provided with an upper liquid inlet pipeline communicated with the top of the tank body and a lower liquid inlet pipeline communicated with the bottom of the tank body; the gas phase pipeline is communicated with the top of the tank body; according to the control device, in the LNG raw material loading process, pre-cooling operation on an LNG tank, a loading arm pipeline and a box body pipeline is achieved through a loading arm in butt joint with a tank car operation box by controlling a passage of an upper liquid inlet pipeline and controlling a disconnection of a lower liquid inlet pipeline; and then the formal loading operation achieved by the loading arm is completed by controlling the passage of the lower liquid inlet pipeline and controlling the disconnection of the upper liquid inlet pipeline, and when it is detected that the pressure in the gas-phase pipeline is abnormal, the passage of the gas-phase pipeline is controlled. Automatic control of the valves in the LNG operation box and automatic loading and unloading of LNG are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and gas storage and transportation safety, and in particular to a tank truck operating box control system and method for LNG loading and unloading sites. Background Art

[0002] LNG is a liquid fossil fuel after natural gas (mainly methane) is compressed and cooled to its freezing point (-161.5℃). It has the characteristics of low temperature and high volatility. At present, LNG is mainly transported by land using tank trucks. LNG (liquefied natural gas) tank trucks mainly include semi-trailers, tanks, pipeline systems and operation boxes, among which the tanks are composed of carbon steel outer cylinders and austenitic stainless steel inner cylinders, and there is a vacuum layer between the inner and outer cylinders; an operation box is set at the rear of the tank and the tail of the LNG tank truck, and operating valves, instruments and necessary pipeline systems are set in the operation box, among which the pipelines include liquid inlet pipelines, booster pipelines and gas phase pipelines for loading and unloading, which are used to connect the LNG tank and the LNG loading arm and its loading control system at the LNG receiving station / LNG liquefaction plant.

[0003] In order to ensure the safety of LNG tanker loading, unloading, storage and transportation, the tanker is equipped with multiple safety devices, including emergency shut-off system, safety system instrument monitoring system, etc., and is also equipped with dry powder fire extinguisher, guardrail, fender, static grounding belt, etc. However, there are many pipelines and valves in the operation box of LNG tanker at present, including liquid inlet valve (gas discharge valve), emergency shut-off valve and necessary safety valve installed on liquid and gas pipelines. During the loading and unloading operation of LNG tanker, flanges are used to connect the gas / liquid pipeline of the tanker and the loading arm, and manual installation / disassembly of flanges and opening or closing of liquid inlet / exhaust valves are required.

[0004] In the prior art, patent document CN216202500U provides a new valve operating box for LNG storage tanks with a quick-opening structure, which mainly improves the opening and closing convenience of the operating box door by setting pins and holes on the operating box body, but cannot solve the problem of automatic control of the valve inside the operation.

[0005] In the prior art, patent document CN109404655A provides a plugging elbow for connecting the shut-off valve and pipeline of the operating box of a low-temperature liquefied vehicle fuel tanker. It mainly treats LNG high leakage risk parts such as the transmission pipeline, flange, valve, etc. in the operating box, and effectively seals the elbow connection between the shut-off valve and the pipeline inside the operating box of the LNG tanker. It cannot solve the problem of quickly cutting off tanker flange leakage during on-site loading and unloading.

[0006] In the prior art, patent document CN203936493U provides a liquefied natural gas tank container and its emergency shut-off system, which solves the problem of power gas source for the emergency shut-off valve by providing its own gas storage tank. However, the gas source pressure of the gas storage tank is often insufficient on the tank truck, and the emergency shut-off valve cannot be opened / closed automatically.

[0007] In the prior art, patent document CN208779123U provides a remotely monitored LNG tank container with automatic loading and unloading functions, which monitors the pressure, liquid level and position information of the LNG tank container through wireless transmission. However, the use of a vehicle-mounted power supply has the problem of unstable power supply during long-term continuous loading of LNG. At the same time, the use of electric valves has the problem of electrical explosion-proof or large size and cannot be installed in the operating box of the LNG tank truck.

[0008] In the prior art, patent document CN210652842U provides a rear operating box for a cryogenic liquid transport vehicle. By adopting a folded edge structure, using side panel reinforcement ribs, door panel reinforcement ribs, folded edge cross beams, etc., the impact resistance of the operating box is improved. However, this method cannot solve the problems of automatic control of valves during LNG loading and passing and remote closure of the operating box shut-off valve in case of accidental leakage.

[0009] In the prior art, patent document CN216942581U provides a rear operating box for a tank-type LNG cryogenic liquid transport semitrailer. By setting a protective mechanism, the internal components of the operating box are protected from damage. However, it cannot solve the problems of automatic control of valves during LNG loading and passing and remote closure of the operating box shut-off valve in case of accidental leakage.

[0010] In the prior art, patent document CN217109129U provides an interlocking control device for LNG loading and unloading trucks, which controls the pneumatic valve to connect the gas source circuit by adding a solenoid valve between the on-board gas source and the pneumatic valve of the LNG tank truck. However, the gas source pressure of the tank truck is insufficient, and it is difficult to meet the automatic control requirements of the pneumatic valve in the operating box.

[0011] Therefore, during LNG loading and unloading operations, loading operators are required to manually operate valves on site, which not only reduces loading and unloading efficiency, but is also more prone to valve misoperation. In addition, once flange leakage or flange detachment occurs, loading operators must manually close the emergency shut-off valve gas source in the operating box to completely close the emergency shut-off valve to prevent continuous leakage of LNG in the tank truck. As a result, the above process involves the risk of operators being exposed to low-temperature LNG and being frostbitten, or even being unable to quickly cut off the emergency shut-off valve in the operating box, resulting in a large amount of LNG leakage, which poses a high risk of combustion and explosion.

[0012] Therefore, the prior art needs to provide an automatic operation box for an LNG tanker and an automatic valve control system thereof to solve the problems in the prior art of easy misoperation of manual operation of LNG loading and unloading vehicles and / or low safety of emergency shut-off system in emergency situations. Summary of the invention

[0013] The purpose of the present invention is to provide an automatic operation box of an LNG tank truck and an automatic valve control scheme thereof, which can solve the problems of easy misoperation of manual operation of LNG loading and unloading trucks and / or low safety of emergency shut-off system in emergency situations.

[0014] In order to solve the above technical problems, an embodiment of the present invention provides a tank truck operating box control system for LNG loading and unloading sites, comprising: a tank body; a liquid phase pipeline, which has an upper liquid inlet pipeline connected to the top of the tank body and a lower liquid inlet pipeline connected to the bottom of the tank body; a gas phase pipeline, which is connected to the top of the tank body; a control device, which, during the LNG loading process, first completes the pre-cooling operation of the LNG tank, the loading arm pipeline and the box pipeline by the loading arm connected to the tank truck operating box through the passage control of the upper liquid inlet pipeline and the circuit breaker control of the lower liquid inlet pipeline, and then completes the formal loading operation by the loading arm through the passage control of the lower liquid inlet pipeline and the circuit breaker control of the upper liquid inlet pipeline, wherein when the pressure abnormality in the gas phase pipeline is detected, the passage control of the gas phase pipeline is performed.

[0015] Preferably, the gas phase pipeline includes: a gas phase stop valve, and a gas phase emergency shut-off valve arranged between the gas phase stop valve and the tank body, wherein the control device is also used to control the gas phase stop valve and the gas phase emergency shut-off valve to open when it is detected that the pressure in the gas phase pipeline exceeds a preset first-level gas phase pipeline pressure threshold and does not reach a preset second-level gas phase pipeline pressure threshold, and the second-level gas phase pipeline pressure threshold is greater than the first-level gas phase pipeline pressure threshold.

[0016] Preferably, the tank truck operating box control system also includes an emptying pipeline, and the gas phase pipeline also includes at least two gas phase emergency emptying valves, wherein the first end of the first gas phase emergency emptying valve is hung on the pipeline between the gas phase stop valve and the gas phase emergency shut-off valve, and the second end of the first gas phase emergency emptying valve is connected to the emptying pipeline, and the first end of the second gas phase emergency emptying valve is hung on the pipeline between the gas phase emergency shut-off valve and the gas phase pipeline inlet, and the second end of the second gas phase emergency emptying valve is connected to the emptying pipeline, wherein the control device is also used to control the opening of the first gas phase emergency emptying valve and / or the second gas phase emergency emptying valve according to the degree of pressure excess when it is detected that the pressure in the gas phase pipeline exceeds the second-level gas phase pipeline pressure threshold.

[0017] Preferably, the emptying pipe is constructed as an arc-shaped structure, wherein the tank truck operation box control system further comprises: a flame arrester arranged at the end of the emptying pipe.

[0018] Preferably, the upper liquid inlet pipeline and the lower liquid inlet pipeline form the same liquid phase pipeline inlet, wherein the lower liquid inlet pipeline is provided with a lower liquid inlet stop valve arranged near the inlet, and a lower liquid inlet emergency shut-off valve arranged at the rear end of the lower liquid inlet stop valve; the upper liquid inlet pipeline is provided with an upper liquid inlet stop valve arranged near the inlet.

[0019] Preferably, the control device controls the loading operation according to the following process: control the upper liquid inlet stop valve to open, and the loading arm injects raw materials into the tank body through the upper liquid inlet pipeline; when it is detected that the tank truck's liquid inlet time reaches a preset specified pre-cooling time or the liquid inlet volume reaches a preset specified pre-cooling liquid inlet volume, control the lower liquid inlet stop valve and the lower liquid inlet emergency shut-off valve to open, and control the upper liquid inlet stop valve to close.

[0020] Preferably, the liquid phase pipeline also includes: a liquid phase emergency drain valve, wherein the first end of the liquid phase emergency drain valve is hung on the pipeline between the lower liquid inlet emergency cut-off valve and the tank body, and the second end of the liquid phase emergency drain valve is connected to the drain pipe.

[0021] Preferably, the tank truck operating box control system also includes: a boosting pipeline connected to the top of the tank body, the boosting pipeline is equipped with a boosting pipeline shut-off valve, a boosting pipeline emergency shut-off valve and a safety valve arranged on the pipeline between the boosting pipeline shut-off valve and the tank body, wherein the first end of the safety valve is hung on the pipeline between the boosting pipeline shut-off valve and the boosting pipeline emergency shut-off valve, and the second end of the safety valve is connected to the drain pipe.

[0022] Preferably, the control device comprises: an on-board control module, which is used to control the loading process according to the sensor information at different positions of each pipeline and the tank body; an air source control module, which is used to control the power of the valve body at different positions in each pipeline under the control of the on-board control module, wherein the air source control module comprises: a first air source assembly, which is used to specify the opening and closing state of the stop valve in each pipeline under the control of the on-board control module; a second air source assembly, which is used to specify the opening and closing state of the emergency shut-off valve in each pipeline under the control of the on-board control module. control; a third gas source assembly, which is used to specify the opening and closing states of the drain valves in each pipeline under the control of the on-board control module; a first control ball valve, a second control ball valve and a third control ball valve respectively located at the front ends of the first gas source assembly, the second gas source assembly and the third gas source assembly, the first control ball valve, the second control ball valve and the third control ball valve being used to control the on-off states between the corresponding gas source assembly and the gas source inlet under the control of the on-board control module; and a gas source inlet valve body connected to the first control ball valve, the second control ball valve and the third control ball valve.

[0023] Preferably, the vehicle-mounted control module is also used to collect real-time pressure data in the gas phase pipeline, pressure data in the tank, gas source inlet pressure data, tank liquid level data and tank vacuum data, and dynamically detect the collected real-time data, so as to issue an audible and visual alarm when abnormal data is detected, wherein the vehicle-mounted control module is powered by the tank truck electrostatic grounding detector module and obtains the tank truck electrostatic grounding status information in real time.

[0024] On the other hand, an embodiment of the present invention provides a loading and unloading mechanism for an LNG loading and unloading site, comprising: a tank truck operating box control system as described above; and a loading arm system connected to the tank truck operating box control system.

[0025] In addition, an embodiment of the present invention further provides a method for controlling a tank truck operating box at an LNG loading and unloading site, wherein the method is implemented according to the tank truck operating box control system as described above, wherein the method comprises: during the LNG loading process, the control device first completes the pre-cooling operation of the LNG tank, the loading arm pipeline and the box pipeline by the loading arm docked with the tank truck operating box by controlling the passage of the upper liquid inlet pipeline connected to the top of the tank body in the liquid phase pipeline and the disconnection control of the lower liquid inlet pipeline connected to the bottom of the tank body in the liquid phase pipeline; and completes the formal loading operation by the loading arm by controlling the passage of the lower liquid inlet pipeline and the disconnection control of the upper liquid inlet pipeline, wherein when the pressure abnormality in the gas phase pipeline is detected, the passage of the gas phase pipeline connected to the top of the tank body is controlled.

[0026] Compared with the prior art, one or more embodiments of the above scheme may have the following advantages or beneficial effects:

[0027] The present invention proposes a control system and method for a tank truck operation box used in LNG loading and unloading sites. The system and method include an operation box, a liquid phase pipeline, a gas phase pipeline, a booster pipeline, and a control device. Manual / pneumatic integrated exhaust valve / liquid inlet valve and manual / pneumatic integrated emergency shut-off valve are installed on the gas phase / liquid phase pipeline; the LNG station site purge nitrogen is used as an external compressed gas source, and the on-board PLC module controls the solenoid valve assembly to realize the opening and closing control of the manual / pneumatic integrated exhaust / liquid inlet cryogenic valve and the manual / pneumatic integrated emergency shut-off valve on the liquid phase pipeline and the gas phase pipeline; the electrostatic grounding detector module is used to power the on-board PLC module, and the communication between the on-board PLC and the matching loading control system (batch controller or PLC) is realized while ensuring the grounding of the tank truck. The present invention can realize the automatic control of the valves in the LNG operation box and the automatic loading and unloading of LNG, and at the same time, in an emergency (for example: low-temperature LNG leakage in the tank truck), the emergency shut-off valve in the tank truck operation box can be quickly closed remotely to reduce the risk of life injury to the operator.

[0028] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0030] Figure 1 This is a schematic diagram of the overall structure of a tank truck operating box control system used in an LNG loading and unloading site according to an embodiment of the present application.

[0031] Figure 2 This is a schematic diagram of the specific structure of a tank truck operating box control system used in an LNG loading and unloading site according to an embodiment of the present application.

[0032] Figure 3 This is a schematic diagram of the implementation principle of the control device in the tank truck operating box control system used in the LNG loading and unloading site according to an embodiment of the present application.

[0033] Figure 4 This is a schematic diagram of the circuit control principle of a tank truck operating box control system for an LNG loading and unloading site according to an embodiment of the present application.

[0034] Figure 5This is an overall step diagram of a method for controlling a tank truck operating box at an LNG loading and unloading site according to an embodiment of the present application. DETAILED DESCRIPTION

[0035] The following will describe the implementation methods of the present invention in detail with reference to the accompanying drawings and embodiments, so that the implementation process of how the present invention applies technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly. It should be noted that as long as there is no conflict, the various embodiments of the present invention and the various features in the embodiments can be combined with each other, and the technical solutions formed are all within the protection scope of the present invention.

[0036] In addition, the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions. Also, although a logical sequence is shown in the flowchart, in some cases, the steps shown or described can be performed in a sequence different from that here.

[0037] The terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments. Unless the context clearly indicates otherwise, the singular forms "one", "one" and "item" used herein are also intended to include plural numbers. It should also be understood that the terms "include" and / or "comprise" used herein specify the existence of stated features, integers, steps, operations, units and / or components, without excluding the existence or addition of one or more other features, integers, steps, operations, units, components and / or combinations thereof.

[0038] LNG is a liquid fossil fuel after natural gas (mainly methane) is compressed and cooled to its freezing point (-161.5℃). It has the characteristics of low temperature and high volatility. At present, LNG is mainly transported by land using tank trucks. LNG (liquefied natural gas) tank trucks mainly include semi-trailers, tanks, pipeline systems and operation boxes, among which the tanks are composed of carbon steel outer cylinders and austenitic stainless steel inner cylinders, and there is a vacuum layer between the inner and outer cylinders; an operation box is set at the rear of the tank and the tail of the LNG tank truck, and operating valves, instruments and necessary pipeline systems are set in the operation box, among which the pipelines include liquid inlet pipelines, booster pipelines and gas phase pipelines for loading and unloading, which are used to connect the LNG tank and the LNG loading arm and its loading control system at the LNG receiving station / LNG liquefaction plant.

[0039] In order to ensure the safety of LNG tanker loading, unloading, storage and transportation, the tanker is equipped with multiple safety devices, including emergency shut-off system, safety system instrument monitoring system, etc., and is also equipped with dry powder fire extinguisher, guardrail, fender, static grounding belt, etc. However, there are many pipelines and valves in the operation box of LNG tanker at present, including liquid inlet valve (gas discharge valve), emergency shut-off valve and necessary safety valve installed on liquid and gas pipelines. During the loading and unloading operation of LNG tanker, flanges are used to connect the gas / liquid pipeline of the tanker and the loading arm, and manual installation / disassembly of flanges and opening or closing of liquid inlet / exhaust valves are required.

[0040] In the prior art, patent document CN216202500U provides a new valve operating box for LNG storage tanks with a quick-opening structure, which mainly improves the opening and closing convenience of the operating box door by setting pins and holes on the operating box body, but cannot solve the problem of automatic control of the valve inside the operation.

[0041] In the prior art, patent document CN109404655A provides a plugging elbow for connecting the shut-off valve and pipeline of the operating box of a low-temperature liquefied vehicle fuel tanker. It mainly treats LNG high leakage risk parts such as the transmission pipeline, flange, valve, etc. in the operating box, and effectively seals the elbow connection between the shut-off valve and the pipeline inside the operating box of the LNG tanker. It cannot solve the problem of quickly cutting off tanker flange leakage during on-site loading and unloading.

[0042] In the prior art, patent document CN203936493U provides a liquefied natural gas tank container and its emergency shut-off system, which solves the problem of power gas source for the emergency shut-off valve by providing its own gas storage tank. However, the gas source pressure of the gas storage tank is often insufficient on the tank truck, and the emergency shut-off valve cannot be opened / closed automatically.

[0043] In the prior art, patent document CN208779123U provides a remotely monitored LNG tank container with automatic loading and unloading functions, which monitors the pressure, liquid level and position information of the LNG tank container through wireless transmission. However, the use of a vehicle-mounted power supply has the problem of unstable power supply during long-term continuous loading of LNG. At the same time, the use of electric valves has the problem of electrical explosion-proof or large size and cannot be installed in the operating box of the LNG tank truck.

[0044] In the prior art, patent document CN210652842U provides a rear operating box for a cryogenic liquid transport vehicle. By adopting a folded edge structure, using side panel reinforcement ribs, door panel reinforcement ribs, folded edge cross beams, etc., the impact resistance of the operating box is improved. However, this method cannot solve the problems of automatic control of valves during LNG loading and passing and remote closure of the operating box shut-off valve in case of accidental leakage.

[0045] In the prior art, patent document CN216942581U provides a rear operating box for a tank-type LNG cryogenic liquid transport semitrailer. By setting a protective mechanism, the internal components of the operating box are protected from damage. However, it cannot solve the problems of automatic control of valves during LNG loading and passing and remote closure of the operating box shut-off valve in case of accidental leakage.

[0046] In the prior art, patent document CN217109129U provides an interlocking control device for LNG loading and unloading trucks, which controls the pneumatic valve to connect the gas source circuit by adding a solenoid valve between the on-board gas source and the pneumatic valve of the LNG tank truck. However, the gas source pressure of the tank truck is insufficient, and it is difficult to meet the automatic control requirements of the pneumatic valve in the operating box.

[0047] Therefore, during LNG loading and unloading operations, loading operators are required to manually operate valves on site, which not only reduces loading and unloading efficiency, but is also more prone to valve misoperation. In addition, once flange leakage or flange detachment occurs, loading operators must manually close the emergency shut-off valve gas source in the operating box to completely close the emergency shut-off valve to prevent continuous leakage of LNG in the tank truck. As a result, the above process involves the risk of operators being exposed to low-temperature LNG and being frostbitten, or even being unable to quickly cut off the emergency shut-off valve in the operating box, resulting in a large amount of LNG leakage, which poses a high risk of combustion and explosion.

[0048] Therefore, the prior art needs to provide an automatic operation box for an LNG tanker and an automatic valve control system thereof to solve the problems in the prior art of easy misoperation of manual operation of LNG loading and unloading vehicles and / or low safety of emergency shut-off system in emergency situations.

[0049] In order to solve the technical problems in the above-mentioned background technology, the embodiment of the present application proposes a tank truck operating box control system and method for LNG loading and unloading sites. The system and method can realize the automatic control of the valve of the LNG tank truck operating box; use the nitrogen purge gas of the LNG receiving / liquefaction plant loading station as the gas source, and the gas source is stable; the on-board PLC module is powered by the tank truck static grounding detector module, and the on-board PLC module communicates with the LNG loading control system at the same time, realizing the full process automation of the LNG loading system and improving the overall safety of the loading operation.

[0050] Embodiment 1

[0051] Figure 1 This is a schematic diagram of the overall structure of the tank truck operating box control system for LNG loading and unloading sites according to an embodiment of the present application. Figure 1 , the overall structure of an embodiment of the present invention is described.

[0052] like Figure 1As shown, the tank truck operating box control system described in the embodiment of the present invention includes: a tank body 4, a liquid phase pipeline 1, a gas phase pipeline 2 and a control device (unnumbered).

[0053] The liquid phase pipeline includes an upper liquid inlet pipeline and a lower liquid inlet pipeline. The upper liquid inlet pipeline is connected to the top of the tank body 4. The lower liquid inlet pipeline is connected to the bottom of the tank body 4. The gas phase pipeline 2 is connected to the top of the tank body 4. The control device can be used to perform pipeline on-off control on the gas phase pipeline 2 and pipeline on-off control on the liquid phase pipeline 1, so as to immediately cut off the internal on-off of the liquid phase pipeline 1 and / or the gas phase pipeline 2 in an emergency (for example: LNG leakage or continuous leakage in the tank truck).

[0054] In addition, the control device is used to complete the pre-cooling operation of the LNG transport pipeline including the LNG tank, the loading arm pipeline and the box pipeline by the loading arm connected to the tank truck operating box during the loading of LNG raw materials by first controlling the access of the upper liquid inlet pipeline and the circuit breaker control of the lower liquid inlet pipeline; and then complete the formal loading operation of LNG by the loading arm by controlling the access of the lower liquid inlet pipeline and the circuit breaker control of the upper liquid inlet pipeline, so as to realize the automatic control of the tank truck operating box during the loading and unloading operation. Among them, the control device is also used to control the access of the gas phase pipeline when the pressure in the gas phase pipeline is detected to be abnormal.

[0055] Figure 2 This is a schematic diagram of the specific structure of the tank truck operating box control system for LNG loading and unloading sites according to an embodiment of the present application. Figure 2 , the specific structure of the tank truck operating box control system described in the embodiment of the present invention is explained.

[0056] like Figure 2 As shown, the upper liquid inlet pipeline and the lower liquid inlet pipeline form the same liquid phase pipeline inlet. The first end of the lower liquid inlet pipeline forms the liquid phase pipeline inlet, and the second end of the lower liquid inlet pipeline is connected to the bottom of the tank body 4. The lower liquid inlet pipeline is provided with a lower liquid inlet stop valve (the stop valve is a manual and pneumatic integrated low temperature stop valve) 101 arranged near the inlet, and a lower liquid inlet emergency shut-off valve (the shut-off valve is a manual and pneumatic integrated low temperature shut-off valve) 102 arranged at the rear end of the lower liquid inlet stop valve 101.

[0057] The first end of the upper liquid inlet pipeline is formed as the liquid phase pipeline inlet, and the second end of the upper liquid inlet pipeline is connected to the top of the tank body 4. The upper liquid inlet pipeline is provided with an upper liquid inlet stop valve (the stop valve is a manual and pneumatic integrated low-temperature stop valve) 104 arranged near the inlet. In addition, the upper liquid inlet pipeline also includes an upper liquid inlet check valve 105. The upper liquid inlet check valve 105 is arranged at the rear end of the upper liquid inlet stop valve 104.

[0058] like Figure 2As shown, the inlet end of the liquid phase pipeline (for example: implemented by DN50) 1 is installed with a quick connector male head, which is fixed by bolts and can be connected with the connector female head at the end of the liquid phase arm of the loading arm. The liquid phase pipeline is divided into an upper liquid inlet pipeline and a lower liquid inlet pipeline, wherein the upper liquid inlet pipeline is sequentially installed with an upper liquid inlet manual / pneumatic integrated low-temperature valve (stop valve) 104 and a check valve 105, and the upper liquid inlet pipeline is connected to the top 401 of the tank body 4; the lower liquid inlet pipeline is sequentially installed with a lower liquid inlet manual / pneumatic integrated low-temperature valve (stop valve) 101 and a lower liquid inlet emergency shut-off valve 102. The lower liquid inlet pipeline is connected to the bottom of the tank body 4.

[0059] The gas phase pipeline 3 includes: a gas phase stop valve (the stop valve is a manual and pneumatic integrated low temperature valve) 301 and a gas phase emergency shut-off valve (the shut-off valve is a manual and pneumatic integrated low temperature shut-off valve) 302. The gas phase emergency shut-off valve 302 is arranged between the gas phase stop valve 301 and the tank body 4.

[0060] In addition, a detection device (i.e., a gas phase pressure detection meter 308) for real-time collection of the internal pressure of the gas phase pipeline is also installed at the rear end of the gas phase emergency shut-off valve 302. The gas phase pressure detection meter 308 is used to monitor the internal pressure of the gas phase pipeline in real time during the loading and unloading operation, and transmit the internal pressure data of the gas phase pipeline to the control device, see Figure 4 .

[0061] In actual application, the control device is also used to control the gas phase stop valve 301 and the gas phase emergency shut-off valve 302 to open when it is detected that the pressure in the gas phase pipeline exceeds the preset first-level gas phase pipeline pressure threshold (for example: 0.6MPa) and does not reach the preset second-level gas phase pipeline pressure threshold (for example: 0.8MPa), so that exhaust is performed through the gas phase pipeline 3. In the embodiment of the present invention, the second-level gas phase pipeline pressure threshold is greater than the first-level gas phase pipeline pressure threshold.

[0062] like Figure 2 As shown, the inlet end of the gas phase pipeline (for example, DN50) 3 is also equipped with a quick connector male head, which is fixed by bolts and can be connected to the connector female head at the end of the gas phase arm of the loading arm. The gas phase pipeline is installed with a gas phase manual / pneumatic integrated low temperature valve (stop valve) 301 and a gas phase emergency shut-off valve 302 in sequence.

[0063] Further, in the present embodiment, the tank truck operation box control system further includes: an emptying pipeline 310. The emptying pipeline 310 is also connected to the liquid phase pipeline 1 and the gas phase pipeline 3 at the same time.

[0064] Specifically, the gas phase pipeline 3 also includes a first gas phase emergency drain valve (the drain valve is a manual and pneumatic integrated cryogenic valve) 303 and a second gas phase emergency drain valve (the drain valve is a manual and pneumatic integrated cryogenic valve) 304. The first end of the first gas phase emergency drain valve 303 is connected to the pipeline between the gas phase stop valve 301 and the gas phase emergency shut-off valve 302, and the second end of the first gas phase emergency drain valve 303 is connected to the drain pipe 310. The first end of the second gas phase emergency drain valve 304 is connected to the pipeline between the gas phase emergency shut-off valve 302 and the gas phase pipeline inlet, and the second end of the second gas phase emergency drain valve 304 is connected to the drain pipe 310.

[0065] In actual application, the control device is also used to control the opening of the first gas phase emergency drain valve and / or the second gas phase emergency drain valve according to the degree of pressure excess when it detects that the pressure in the gas phase pipeline exceeds the above-mentioned second-level gas phase pipeline pressure threshold (for example: 0.8MPa).

[0066] Specifically, in one embodiment, the control device is further used to control the first gas phase emergency drain valve or the second gas phase emergency drain valve to open when the pressure exceeds the first pressure difference threshold. In another embodiment, the control device is further used to control the first gas phase emergency drain valve and the second gas phase emergency drain valve to open simultaneously when the pressure exceeds the second pressure difference threshold. The second pressure difference threshold is higher than the first pressure difference threshold.

[0067] Furthermore, the emptying pipe 310 is constructed as an arc structure. The tank truck operation box control system further includes: a flame arrester 309 arranged at the end of the emptying pipe.

[0068] A gas phase emergency emptying manual / pneumatic integrated cryogenic valve 303 is installed by welding a three-way pipe between the gas phase emergency shut-off valve 302 and the gas phase pressure detection gauge 308. The gas phase emergency emptying manual / pneumatic integrated cryogenic valve 303 is connected to the emptying pipe 310 of the tank body of the tank truck. Among them, a flame arrester 309 is installed at the end of the emptying pipe 310 (to ensure the safety of the emptying operation), and the end of the emptying pipe 310 is constructed as an arc-shaped structure pipe. The gas phase pipeline 3 is close to the connection of the tank body 4 and is connected to the three-way valve 305 through a three-way pipe. Two safety valves 306 and 307 are installed at both ends of the three-way valve 305, respectively, and the safety valves 306 and 307 are connected to the emptying pipe 310. The inlet end of the gas phase pipeline is connected to the gas phase manual / pneumatic integrated low-temperature valve (stop valve) 301, and a gas phase emptying control valve 304 is installed through a three-way pipeline. The gas phase emptying control valve 304 is connected to the tank emptying pipeline 310 of the tank truck.

[0069] Furthermore, the liquid phase pipeline 1 also includes: a liquid phase emergency drain valve (the drain valve is a manual and pneumatic integrated cryogenic valve) 103. The first end of the liquid phase emergency drain valve 103 is connected to the pipeline between the lower liquid inlet emergency shut-off valve 102 and the tank body 4, and the second end of the liquid phase emergency drain valve 103 is connected to the drain pipe 310.

[0070] Specifically, the connecting pipe between the lower liquid inlet emergency shut-off valve 102 and the tank body 4 is installed with a manual / pneumatic integrated cryogenic valve 103 for emergency liquid phase emptying through a three-way pipe, and the manual / pneumatic integrated cryogenic valve 103 for emergency liquid phase emptying is connected to the tank emptying pipe 310 of the tank truck. In addition, a safety valve 106 is installed between the manual / pneumatic integrated cryogenic valve (stop valve) 101 of the liquid phase pipeline 1 and the lower liquid inlet emergency shut-off valve 102 through a three-way pipe. The safety valve 106 is used to empty the pressurized gas after LNG gasification between the cryogenic valve (stop valve) 101 and the liquid emergency shut-off valve 102 after the LNG tank truck is loaded. Among them, the safety valve 106 is connected to the tank emptying pipe 310 of the tank truck.

[0071] It should be noted that, in the embodiment of the present invention, all valve bodies such as manual / pneumatic integrated cryogenic valves, emergency shut-off valves, drain valves, etc. are connected to the pipeline by welding to save the internal space of the tank truck.

[0072] In addition, in the embodiment of the present invention, the LNG tanker body 4 is constructed as a double-layer structure. A first pressure gauge 403 and a liquid level (high level) alarm detection gauge 402 are installed on the top of the inner wall 401. The first pressure gauge 403 is used to detect the pressure in the tank in real time during the loading and unloading operation, and transmit the pressure data in the tank to the control device, see Figure 4 The liquid level (high level) alarm detection table 402 is used to detect the liquid level in the tank in real time during the loading and unloading operation, and transmit the liquid level data in the tank to the control device, see Figure 4 Moreover, a vacuum degree detection meter 404 is connected to the outer wall of the tank body 4. The vacuum degree detection meter 404 is used to monitor the vacuum degree of the vacuum layer formed between the inner wall and the outer wall of the tank in real time during the loading and unloading operation, and transmit the vacuum degree data to the control device, see Figure 4 .

[0073] In addition, the tank truck operation box control system also includes: a boosting pipeline 2. The boosting pipeline 2 is connected to the top of the tank body 4. The boosting pipeline 2 has: a boosting pipeline stop valve (the stop valve is a manual and pneumatic integrated low-temperature valve) 201, a boosting pipeline emergency shut-off valve (the shut-off valve is a manual and pneumatic integrated low-temperature shut-off valve) 202 and a safety valve 203 arranged on the pipeline between the boosting pipeline stop valve 201 and the tank body 4. Among them, the first end of the safety valve 203 is hung on the pipeline between the boosting pipeline emergency shut-off valve and the boosting pipeline emergency shut-off valve 202, and the second end of the safety valve 203 is connected to the emptying pipeline 310.

[0074] like Figure 2 As shown, a flange is installed at the inlet end of the boosting pipeline (for example, DN50 is used) 2, and a boosting gas phase manual / pneumatic integrated cryogenic valve (stop valve) 201 and a boosting emergency shut-off valve 202 are installed on the boosting pipeline 2 in sequence, wherein the boosting emergency shut-off valve 202 is connected to the top of the tank body 4. A safety valve 203 is installed between the boosting gas phase manual / pneumatic integrated cryogenic valve (stop valve) 201 and the boosting emergency shut-off valve 202 through a three-way pipeline, and the safety valve 203 is used to empty the pressurized gas between the cryogenic valve (stop valve) 201 and the emergency shut-off valve 202 after the LNG tank truck is unloaded. Among them, the safety valve 203 is connected to the tank truck tank emptying pipeline 310.

[0075] Figure 3 This is a schematic diagram of the implementation principle of the control device in the tank truck operating box control system used in the LNG loading and unloading site according to an embodiment of the present application. Figure 4 This is a schematic diagram of the circuit control principle of a tank truck operating box control system for an LNG loading and unloading site according to an embodiment of the present application.

[0076] refer to Figure 3 and Figure 4 The control device described in the embodiment of the present invention includes a vehicle-mounted control (PLC) module 8 and an air source control module (unnumbered).

[0077] The vehicle control module 8 is used to control the loading process according to the sensor information at different positions in each pipeline and tank. The air source control module is used to control the power of the valve body at different positions in each pipeline under the control of the vehicle control module 8.

[0078] Furthermore, the gas source control module includes: a first gas source assembly 601 , a second gas source assembly 602 , a third gas source assembly 603 , a first control ball valve 701 , a second control ball valve 702 , a third control ball valve 703 and a gas source inlet valve body 5 .

[0079] The first gas source assembly 601 is used to specify the opening and closing state of the stop valve in each pipeline under the control of the vehicle control module 8. The second gas source assembly 602 is used to specify the opening and closing state of the emergency shut-off valve in each pipeline under the control of the vehicle control module 8. The third gas source assembly 603 is used to specify the opening and closing state of the exhaust valve in each pipeline under the control of the vehicle control module 8.

[0080] The first control ball valve 701 is located at the front end of the first gas source assembly 601. The second control ball valve 702 is located at the front end of the second gas source assembly 602. The third control ball valve 703 is located at the front end of the third gas source assembly 603. The first control ball valve is used to control the on-off state between the first gas source assembly 601 and the gas source inlet under the control of the vehicle control module 8; the second control ball valve is used to control the on-off state between the second gas source assembly 602 and the gas source inlet under the control of the vehicle control module 8; the third control ball valve is used to control the on-off state between the third gas source assembly 603 and the gas source inlet under the control of the vehicle control module 8.

[0081] The gas source inlet valve body 5 is connected to the first control ball valve 701 , the second control ball valve 702 and the third control ball valve 703 at the same time.

[0082] Figure 3 The schematic diagram of the pneumatic control gas circuit connection of the valve of the automatic operation box of the LNG tanker is shown. Among them, the stop valves in each pipeline are controlled by a compressed nitrogen gas source and controlled by the first gas source control solenoid valve assembly (first gas source assembly) 601. Specifically, the lower liquid inlet manual / pneumatic integrated cryogenic valve (stop valve) 101, the upper liquid inlet manual / pneumatic integrated cryogenic valve (stop valve) 104, the boost manual / pneumatic integrated cryogenic valve (stop valve) 201, and the gas phase manual / pneumatic integrated cryogenic valve (stop valve) 301 used in the liquid phase pipeline 1, the gas phase pipeline 3, and the boost pipeline 2 are all controlled by a compressed nitrogen gas source, and the first gas source control solenoid valve assembly 601 controls the opening and closing of the manual / pneumatic integrated cryogenic valve (stop valve) under the action of the on-board control module.

[0083] The cut-off valves in each pipeline are also controlled by compressed nitrogen gas source and controlled by the second gas source control solenoid valve assembly (second gas source assembly) 602. Specifically, the lower liquid emergency cut-off valve 102, the boost emergency cut-off valve 202 and the gas phase emergency cut-off valve 302 will be controlled by the second gas source control solenoid valve assembly 602 to open and close the designated emergency cut-off valves under the action of the vehicle control module.

[0084] The drain valves in each pipeline are also controlled by compressed nitrogen gas source and controlled by the third gas source control solenoid valve assembly (third gas source assembly) 603. Specifically, the liquid phase emergency drain manual / pneumatic integrated cryogenic valve 103, the gas phase emergency drain manual / pneumatic integrated cryogenic valve 303, and the gas phase drain control valve 304 will control the opening and closing of the designated drain valve through the third gas source control solenoid valve assembly 603 under the action of the vehicle control module.

[0085] In the embodiment of the present invention, the control gas source of each manual / pneumatic integrated cryogenic valve (stop valve), each emergency shut-off valve, and each exhaust control valve adopts an external compressed controlled nitrogen gas source to realize power supply, wherein the nitrogen gas source pressure is not less than 0.6MPa.

[0086] like Figure 3 As shown, the compressed gas source inlet is equipped with a gas source inlet valve body (pressure reducing valve) 5. A second pressure gauge 501 is installed at the rear end of the pressure reducing valve 5. The second pressure gauge 501 is used to detect the gas source inlet pressure in real time during the loading and unloading operation, and transmit the gas source inlet pressure data to the control device, see Figure 4 The rear end of the second pressure gauge 501 delivers compressed gas to the first gas source control solenoid valve assembly 601, the second gas source control solenoid valve assembly 602, and the third gas source control solenoid valve assembly 603 through a stainless steel gas source connecting pipe (for example, the gas source connecting pipes are all φ8 stainless steel gas pipes). The first control ball valve 701, the second control ball valve 702, and the third control ball valve 703 are installed between the first to third gas source control electronic valve assemblies 601 to 603 and the second pressure gauge 501.

[0087] In the embodiment of the present invention, the compressed nitrogen gas source adopts the compressed nitrogen gas for purging in the LNG station. The operation box at the rear of the tank truck is equipped with a gas source connector. After the tank truck stops at the loading station, the quick-connect gas source connector of the loading station is directly connected to the tank truck gas source connector to provide a power gas source for opening valve bodies such as manual / pneumatic integrated cryogenic valves (stop valves), emergency shut-off valves and drain valves.

[0088] A gas source connector is installed on each side of the operation box at the rear of the tank truck, and a ball valve is installed behind the gas source connector to ensure that when the LNG tank truck is parked at the LNG loading platform, the nitrogen purge pipeline provided by any loading skid on both sides of the tank truck can be connected to the tank truck gas source connector. Before the tank truck is connected to the gas source, the ball valves of the gas source structure on both sides remain closed. After any side is connected to the gas source, the ball valves 701-703 on the corresponding side are opened; similarly, when the gas source is disconnected, the ball valves 701-703 on the corresponding side are closed.

[0089] Figure 4 This is a schematic diagram of the circuit control principle of the tank truck operating box control system for LNG loading and unloading sites according to an embodiment of the present application. Figure 4 The vehicle-mounted control module described in the embodiment of the present invention is also used to collect real-time pressure data in the gas phase pipeline, pressure data in the tank, gas source inlet pressure data, tank liquid level data and tank vacuum data during loading and unloading operations, and dynamically detect the collected real-time data, so as to issue an audible and visual alarm when abnormal data is detected.

[0090] Figure 4 The circuit control principle diagram of the automatic operation box of the LNG tanker is shown. A small vehicle-mounted PLC module (i.e., vehicle-mounted control module 8, which can be implemented by a programmable logic controller) is installed on the side of the LNG tanker operation box and the tank body 4.

[0091] The vehicle-mounted control module is used to control the opening and closing of the first gas source control solenoid valve assembly 601, the second gas source control solenoid valve assembly 602, and the third gas source control solenoid valve assembly 603. The gas phase pressure detection gauge 308 (third pressure gauge) and the second pressure gauge 501 are transmitted to the vehicle-mounted control module. At the same time, the data of the level gauge 401 for detecting the liquid level in the tank installed on the tank body 4 of the tank truck, the first pressure gauge 403 for detecting the pressure in the tank, and the vacuum degree detection gauge 404 for detecting the inner wall and vacuum of the tank are transmitted to the vehicle-mounted control module through the 4-20mA signal line, thereby ensuring the stability of data transmission through wired connection. In addition, the vehicle-mounted PLC module comes with an audible and visual alarm module to issue an audible and visual alarm when abnormal data is detected.

[0092] The vehicle-mounted control module 8 is powered by the tank truck static grounding detector module 9 in the LNG loading system. The vehicle-mounted PLC module (i.e., the vehicle-mounted control module) 8 in the present invention is powered by the tank truck static grounding detector module 9 in the LNG loading system, so that the risk of accidental power failure of the vehicle-mounted power supply can be prevented to the maximum extent.

[0093] In actual application, the electrostatic grounding detector module on the tank truck uses a multi-core (e.g., 10-core) connecting wire to install an explosion-proof plug, and the explosion-proof plug is connected to the multi-core explosion-proof socket on the vehicle-mounted PLC module 8 through contacts. The tank body of the tank truck is welded with a grounding point, which is connected to the vehicle-mounted PLC module through a grounding wire. In this way, the connection between the tank truck electrostatic grounding detector module and the tank body of the tank truck is realized through the vehicle-mounted PLC module.

[0094] In addition, the tank truck static electricity detector module 9 is also directly connected to the LNG loading arm control system 10. In this way, the vehicle-mounted PLC module 8 in the control device of the present invention can communicate with the LNG loading arm (control) system 10 through the tank truck static electricity detector module 9, so that the loading arm system and the tank truck operation box system can understand each other and grasp the progress of different operations in the same loading and unloading operation.

[0095] In addition, the vehicle-mounted control module described in the embodiment of the present invention is also used to obtain in real time the tank truck's electrostatic grounding status information monitored by the tank truck's electrostatic grounding detector module, so that the vehicle-mounted control module can understand in real time whether the tank truck's electrostatic grounding status is good (or abnormal).

[0096] Embodiment 2

[0097] Based on the above-mentioned embodiment 1, the implementation process of the tank truck operating box control system of the present invention is specifically described below.

[0098] After the LNG tank truck is stabilized at the LNG receiving station or the LNG liquefaction plant loading station, the LNG loading system loading arm (specifically including: liquid phase arm and gas phase arm) is connected through a flange or LNG quick connector, so that the loading arm is connected to the liquid phase pipeline 1 and the gas phase pipeline 3 in the tank truck operating box accordingly.

[0099] When starting LNG loading operations, the main steps are as follows:

[0100] Step 1: Open the operating box door at the rear of the tank truck. The loader inserts the on-site compressed gas source (compressed nitrogen) connector (metal quick-plug connector-daughter body) into the gas source connector (parent body) in the tank truck operating box to realize the connection of the operating box to control the gas source. The control device controls the pressure reducing valve 5 so that the gas source inlet pressure (the reading of the second pressure gauge 501) is maintained within the range of 0.4MPa to 0.7MPa.

[0101] Step 2: The loading operator connects the tank truck static grounding detector module to the on-board PLC module through a quick-plug explosion-proof connector. The on-board PLC module displays that the power is normal. The control device monitors whether the data information sent by the gas phase pressure detection gauge 308 (third pressure gauge), the second pressure gauge 501, the first pressure gauge 403, and the vacuum detection gauge 404 is normal. Otherwise, the sound and light alarm module of the on-board PLC module will sound an alarm. At the same time, the various instruments and PLC modules of the tank truck need to be inspected. When the sound and light alarm module in the on-board PLC module has no sound and light alarm, and the control device detects that the tank truck grounding state of the tank truck static grounding detection module is normal, the control device outputs the instruction information allowing the loading operation to allow loading.

[0102] Step 3: Start loading.

[0103] In one embodiment, the control device controls the loading operation according to the following process:

[0104] First, the upper liquid inlet stop valve 104 is controlled to open (the check valve 105 is in a normally open state and the booster pipeline remains closed), and the loading arm injects LNG raw materials into the tank through the upper liquid inlet pipeline;

[0105] Then, when it is detected that the tank truck liquid inlet time reaches the preset specified precooling time or the liquid inlet amount reaches the preset specified precooling liquid inlet amount, the lower liquid inlet stop valve 101 and the lower liquid inlet emergency shut-off valve 102 are controlled to open, and the upper liquid inlet stop valve 104 is controlled to close.

[0106] Specifically, the on-board control module in the control device first controls the second control ball valve 702 to be in a normally closed state, controls the boost manual / pneumatic integrated low-temperature valve 201 and the boost emergency shut-off valve 202 to be closed, so that the boost pipeline remains in a closed state; the on-board control module controls the first control ball valve 701 to be normally open, controls the first air source control solenoid valve assembly 601 to open the upper liquid inlet manual / pneumatic integrated low-temperature valve 104, and after the tank truck has been filling liquid for about 5 minutes or the liquid filling volume reaches 500-700kg, opens the lower liquid inlet manual / pneumatic integrated low-temperature valve 101 and the lower liquid inlet emergency shut-off valve 102, and at the same time, controls the liquid inlet manual / pneumatic integrated low-temperature valve 104 to be closed.

[0107] Next, the third control ball valve 703 is controlled to be normally open. When the gas phase pressure detection gauge 308 on the gas phase pipeline shows a reading exceeding 0.6MPa, the on-board PLC control module controls the second gas source control solenoid valve assembly 602 to open the gas phase manual / pneumatic integrated low-temperature valve 301 and the gas phase emergency shut-off valve 302; when the gas pressure in the tank continues to rise to above 0.8MPa, the on-board PLC control module controls the third gas source control solenoid valve assembly 603 to open the gas phase emergency emptying manual / pneumatic integrated low-temperature valve 303 and / or low-temperature valve 304 according to the degree of pressure excess, so that under different internal pressure conditions of the gas phase pipeline, the high-pressure gas in the tank can be urgently discharged through the emptying control valve 309 and the emptying pipeline 310.

[0108] In addition, when it is detected that the pressure in the gas phase pipeline collected in real time by the gas phase pressure detection meter 308 is lower than 0.6 MPa, the manual / pneumatic integrated low-temperature valves 303 and 304 for emergency exhaust of the gas phase can be closed.

[0109] Step 4: Loading is completed.

[0110] The on-board PLC control module first controls the lower liquid inlet manual / pneumatic integrated low-temperature valve 101 and the lower liquid inlet emergency shut-off valve 102 to close;

[0111] Then, the safety valves 106 and 203 in each pipeline are controlled to open, so that after the residual LNG in the gas phase arm and the liquid phase arm of the loading system is emptied, the liquid phase pipeline 1 and the gas phase pipeline 3 of the tank truck operation box are controlled to be disconnected from the gas phase arm and the liquid phase arm of the LNG loading system respectively;

[0112] Disconnect the tank car's electrostatic grounding detection module from the onboard PLC module;

[0113] Disconnect the gas source;

[0114] Close the tank truck operating box door to complete the loading of the LNG tank truck.

[0115] The valve action sequence described in the above-mentioned embodiment 2 cannot be changed. If the gas phase arm / liquid phase arm of the on-site loading system of the LNG receiving station / liquefaction project and the gas phase / liquid phase pipeline of the tank truck leaks or even accidentally falls off during the loading process, the low temperature characteristics of the low temperature (-162℃) LNG do not allow it to contact the loading workers to prevent frostbite. For this reason, the control device can remotely disconnect the compressed nitrogen gas source at the front end of the pressure reducing valve 5, and close the corresponding emergency shut-off valves 102 and 302 on the liquid phase pipeline 1 and the gas phase pipeline 3 of the tank truck operation box, without manually closing the emergency shut-off valve of the tank truck operation box on site, to prevent the loaded LNG from continuing to leak and frostbite the workers.

[0116] Embodiment 3

[0117] Based on the tank truck operation box control system provided in the above embodiment 1 and / or embodiment 2, the embodiment of the present invention further provides a loading and unloading mechanism for LNG loading and unloading sites. The loading and unloading mechanism comprises: the tank truck operation box control system as described in the above embodiment 1 and / or embodiment 2; and a loading arm system connected to the tank truck operation box control system.

[0118] In this way, by connecting the loading arm system described in the embodiment of the present invention with the tank truck operating box control system, it is possible to achieve an automatic control effect of the entire process of the tank truck operating box in the complete tank truck loading and unloading operation.

[0119] Embodiment 4

[0120] Based on the tank truck operation box control system provided in the above embodiment 1 and / or embodiment 2, the present invention also provides a tank truck operation box control method for LNG loading and unloading sites. The tank truck operation box control method is implemented according to the tank truck operation box control system as described above.

[0121] Figure 5 FIG. 1 is an overall step diagram of a tank truck operation box control method for an LNG loading and unloading site according to an embodiment of the present application. Figure 5 As shown, the tank truck operating box control method according to the embodiment of the present invention comprises the following steps:

[0122] Step S501, during the process of loading the LNG raw material, the control device first completes the precooling operation of the LNG tank, the loading arm pipeline and the tank pipeline by controlling the passage of the upper liquid inlet pipeline in the liquid phase pipeline 1 connected to the top of the tank body 4 and the disconnection control of the lower liquid inlet pipeline in the liquid phase pipeline 1 connected to the bottom of the tank body 4;

[0123] Step S502: The control device completes the formal loading operation by the loading arm by controlling the passage of the lower liquid inlet pipeline and the circuit breaker of the upper liquid inlet pipeline. When the pressure in the gas phase pipeline is detected to be abnormal, the passage of the gas phase pipeline connected to the top of the tank body 4 is controlled.

[0124] The present invention discloses a control system and method for a tank truck operation box used in LNG loading and unloading sites. The system and method include an operation box, a liquid phase pipeline, a gas phase pipeline, a booster pipeline, and a control device. Manual / pneumatic integrated exhaust valve / liquid inlet valve and manual / pneumatic integrated emergency shut-off valve are installed on the gas phase / liquid phase pipeline; the on-site purge nitrogen of the LNG station is used as an external compressed gas source, and the on-board PLC module is used to control the solenoid valve assembly to realize the opening and closing control of the manual / pneumatic integrated exhaust / liquid inlet cryogenic valve and the manual / pneumatic integrated emergency shut-off valve on the liquid phase pipeline and the gas phase pipeline; the electrostatic grounding detector module is used to power the on-board PLC module, and the communication between the on-board PLC and the matching loading control system (batch controller or PLC) is realized while ensuring the grounding of the tank truck. The present invention can realize the automatic control of the valves in the LNG operation box and the automatic loading and unloading of LNG, and at the same time, in an emergency (for example: low-temperature LNG leakage in the tank truck), the emergency shut-off valve in the tank truck operation box can be quickly closed remotely to reduce the risk of life injury to the operator.

[0125] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any person familiar with the technology within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

[0126] In the description of the present invention, unless otherwise specified, "plurality" means two or more than two; the orientations or positional relationships indicated by the terms "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0127] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0128] It should be understood that the embodiments disclosed in the present invention are not limited to the specific structures, processing steps or materials disclosed herein, but should be extended to equivalent substitutions of these features understood by ordinary technicians in the relevant field. It should also be understood that the terms used herein are only used for the purpose of describing specific embodiments and are not meant to be limiting.

[0129] The "one embodiment" or "embodiment" mentioned in the specification means that the specific features, structures or characteristics described in conjunction with the embodiment are included in at least one embodiment of the present invention. Therefore, the phrases "one embodiment" or "embodiment" appearing in various places throughout the specification do not necessarily refer to the same embodiment.

[0130] Although the embodiments disclosed in the present invention are as above, the contents described are only embodiments adopted for facilitating the understanding of the present invention and are not intended to limit the present invention. Any technician in the technical field to which the present invention belongs can make any modifications and changes in the form and details of the implementation without departing from the spirit and scope disclosed in the present invention, but the patent protection scope of the present invention shall still be subject to the scope defined in the attached claims.

Claims

1. A tank truck operating box control system for LNG loading and unloading sites, characterized in that: include: Tank; A liquid phase pipeline, comprising an upper liquid inlet pipeline connected to the top of the tank body and a lower liquid inlet pipeline connected to the bottom of the tank body; A gas phase pipeline connected to the top of the tank; A control device, during the process of loading LNG, first completes the pre-cooling operation of the LNG tank, the loading arm pipeline and the box pipeline by the loading arm connected to the tank truck operating box through the passage control of the upper liquid inlet pipeline and the circuit breaker control of the lower liquid inlet pipeline, and then completes the formal loading operation by the loading arm through the passage control of the lower liquid inlet pipeline and the circuit breaker control of the upper liquid inlet pipeline, wherein when abnormal pressure in the gas phase pipeline is detected, the passage control of the gas phase pipeline is performed.

2. The tank truck operation box control system according to claim 1, characterized in that: The gas phase pipeline comprises: A gas phase shut-off valve, and a gas phase emergency shut-off valve arranged between the gas phase shut-off valve and the tank body, wherein: The control device is also used to control the gas phase stop valve and the gas phase emergency shut-off valve to open when it is detected that the pressure in the gas phase pipeline exceeds a preset first-level gas phase pipeline pressure threshold and does not reach a preset second-level gas phase pipeline pressure threshold, and the second-level gas phase pipeline pressure threshold is greater than the first-level gas phase pipeline pressure threshold.

3. The tank truck operation box control system according to claim 2, characterized in that: The tank truck operation box control system also includes an emptying pipeline, and the gas phase pipeline also includes at least two gas phase emergency emptying valves, wherein the first end of the first gas phase emergency emptying valve is hung on the pipeline between the gas phase stop valve and the gas phase emergency shut-off valve, and the second end of the first gas phase emergency emptying valve is connected to the emptying pipeline, and the first end of the second gas phase emergency emptying valve is hung on the pipeline between the gas phase emergency shut-off valve and the gas phase pipeline inlet, and the second end of the second gas phase emergency emptying valve is connected to the emptying pipeline, wherein, The control device is also used to control the opening of the first gas phase emergency drain valve and / or the second gas phase emergency drain valve according to the degree of pressure excess when it is detected that the pressure in the gas phase pipeline exceeds the second-level gas phase pipeline pressure threshold.

4. The tank truck operation box control system according to claim 3, characterized in that: The emptying pipe is constructed as an arc-shaped structure, wherein the tank truck operation box control system further includes: a flame arrester arranged at the end of the emptying pipe.

5. The tank truck operation box control system according to any one of claims 1 to 4, characterized in that: The upper liquid inlet pipeline and the lower liquid inlet pipeline form a same liquid phase pipeline inlet, wherein, The lower liquid inlet pipeline is provided with a lower liquid inlet stop valve arranged near the inlet, and a lower liquid inlet emergency shut-off valve arranged at the rear end of the lower liquid inlet stop valve; The upper liquid inlet pipeline is provided with an upper liquid inlet stop valve arranged near the inlet.

6. The tank truck operation box control system according to claim 5, characterized in that: The control device controls the loading operation according to the following process: Control the upper liquid inlet stop valve to open, and inject raw materials into the tank body through the upper liquid inlet pipeline by the loading arm; When it is detected that the tank truck liquid inlet time reaches the preset specified pre-cooling time or the liquid inlet amount reaches the preset specified pre-cooling liquid inlet amount, the lower liquid inlet stop valve and the lower liquid inlet emergency shut-off valve are controlled to open, and the upper liquid inlet stop valve is controlled to close.

7. The tank truck operation box control system according to claim 5 or 6, characterized in that: The liquid phase pipeline also includes: a liquid phase emergency drain valve, wherein the first end of the liquid phase emergency drain valve is hung on the pipeline between the lower liquid inlet emergency cut-off valve and the tank body, and the second end of the liquid phase emergency drain valve is connected to the drain pipe.

8. The tank truck operation box control system according to any one of claims 1 to 7, characterized in that: The tank truck operation box control system also includes: A boosting pipeline connected to the top of the tank body, the boosting pipeline is provided with a boosting pipeline stop valve, a boosting pipeline emergency shut-off valve and a safety valve arranged on the pipeline between the boosting pipeline stop valve and the tank body, wherein the first end of the safety valve is hung on the pipeline between the boosting pipeline stop valve and the boosting pipeline emergency shut-off valve, and the second end of the safety valve is connected to the exhaust pipe.

9. The tank truck operation box control system according to any one of claims 1 to 8, characterized in that: The control device comprises: The vehicle control module is used to control the loading process according to the sensor information at different positions of each pipeline and tank body; The air source control module is used to control the power of valve bodies at different positions in each pipeline under the control of the vehicle-mounted control module, wherein the air source control module includes: A first gas source assembly, which is used to specify the opening and closing states of the stop valves in each pipeline under the control of the vehicle-mounted control module; A second gas source assembly, which is used to specify the opening and closing states of the emergency shut-off valves in each pipeline under the control of the vehicle-mounted control module; A third gas source assembly, which is used to specify the opening and closing states of the exhaust valves in each pipeline under the control of the vehicle-mounted control module; A first control ball valve, a second control ball valve and a third control ball valve respectively located at the front end of the first gas source assembly, the second gas source assembly and the third gas source assembly, the first control ball valve, the second control ball valve and the third control ball valve being used to control the on-off state between the corresponding gas source assembly and the gas source inlet under the control of the vehicle-mounted control module; An air source inlet valve body connected to the first control ball valve, the second control ball valve and the third control ball valve at the same time.

10. The tank truck operation box control system according to claim 9, characterized in that: The vehicle-mounted control module is also used to collect real-time pressure data in the gas phase pipeline, pressure data in the tank, gas source inlet pressure data, tank liquid level data and tank vacuum data, and dynamically detect the collected real-time data, so as to perform sound and light alarms when abnormal data is detected, wherein: The vehicle-mounted control module is powered by the tank truck electrostatic grounding detector module and obtains the tank truck electrostatic grounding status information in real time.

11. A loading and unloading mechanism for LNG loading and unloading sites, characterized in that: include: The tank truck operating box control system according to any one of claims 1 to 10; A loading arm system connected to the tank truck operating box control system.

12. A method for controlling a tank truck operating box at an LNG loading and unloading site, characterized in that: The tank truck operation box control method is implemented according to the tank truck operation box control system according to any one of claims 1 to 10, wherein the tank truck operation box control method comprises: During the LNG loading process, the control device first completes the precooling operation of the LNG tank, the loading arm pipeline and the tank pipeline by controlling the passage of the upper liquid inlet pipeline in the liquid phase pipeline connected to the top of the tank body and the disconnection control of the lower liquid inlet pipeline in the liquid phase pipeline connected to the bottom of the tank body through the loading arm connected to the tank truck operation box; The formal loading operation performed by the loading arm is completed by controlling the passage of the lower liquid inlet pipeline and the circuit breaker of the upper liquid inlet pipeline, wherein when an abnormal pressure in the gas phase pipeline is detected, the passage of the gas phase pipeline connected to the top of the tank body is controlled.

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