A tank truck operation box control system and method for an LNG loading and unloading site

Abstract

The application discloses a tank truck operation box control system and method for LNG loading and unloading sites, which comprises a tank body, a liquid phase pipeline 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, a gas phase pipeline communicated with the top of the tank body, and a control device. In the process of loading LNG raw materials, the control device first completes the pre-cooling operation of the LNG tank, the loading arm pipeline and the box pipeline realized by the loading arm connected with the tank truck operation box by controlling the passage of the upper liquid inlet pipeline and breaking the circuit of the lower liquid inlet pipeline, and then completes the formal loading operation realized by the loading arm by controlling the passage of the lower liquid inlet pipeline and breaking the circuit 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 is controlled. The application realizes the automatic control of the valves in the LNG operation box and the automatic loading and unloading of LNG.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil and gas storage and transportation safety, and in particular to a tank truck operation box control system and method for an LNG loading and unloading site. BACKGROUND

[0002] LNG is a liquid fossil fuel obtained by compressing and cooling natural gas (mainly methane) to its condensation point (-161.5℃). It has the characteristics of low temperature and easy evaporation. Currently, LNG is mainly transported by road using tanker trucks. The LNG tanker mainly includes a semitrailer, a tank, a pipeline system and an operation box, etc. The tank is composed of a carbon steel outer cylinder and an austenitic stainless steel inner cylinder, and a vacuum layer is provided between the inner cylinder and the outer cylinder. An operation box is provided at the rear of the tank and the tail of the LNG tanker, and the operation box is provided with operation valves, instruments and necessary pipeline systems. The pipeline includes a liquid inlet pipeline, a booster pipeline and a gas phase pipeline for loading and unloading, which is used to connect the LNG tank and the LNG loading arm and its loading control system of the LNG receiving station / LNG liquefaction plant site.

[0003] To ensure the safety of LNG tanker loading and unloading, storage and transportation, the tank of the tanker is provided with multiple safety devices, including an emergency shut-off system, a safety system instrument monitoring system, etc., as well as dry powder extinguishers, guardrails, mudguards, static grounding belts, etc. However, there are many pipelines and valves in the operation box of the LNG tanker at present, including liquid phase and gas phase pipelines, liquid inlet valves (gas discharge valves), emergency shut-off valves and necessary safety valves. During the loading and unloading operation of the LNG tanker, the flanges of the tanker gas phase / liquid phase pipelines and the loading arm are connected, and the flanges need to be manually installed / dismounted and the liquid inlet / exhaust valves need to be opened or closed.

[0004] In the prior art, patent document CN216202500U provides a new LNG storage tank valve operation box with a quick opening structure, which mainly improves the opening and closing convenience of the operation box door by providing a latch and a hole in the operation box body, but cannot solve the problem of automatic control of the internal valves.

[0005] In the prior art, patent document CN109404655A provides a low-temperature liquefied vehicle fuel tank truck operation box stop valve and pipeline connection leak stop elbow, which mainly processes the LNG high leakage risk parts such as the delivery pipeline, flange and valve in the operation box, effectively seals the elbow connection between the internal stop valve and the pipeline of the LNG tank truck operation box, but cannot solve the problem of quickly cutting off the flange leakage of the tanker during on-site loading and unloading.

[0006] In the prior art, patent document CN203936493U provides a liquefied natural gas tank truck container and its emergency shutdown system, which solves the problem of emergency shutdown valve power gas source by providing a self-contained gas tank, but the gas tank gas source on the automobile tank truck is prone to insufficient pressure, and the emergency shutdown valve cannot be automatically opened / closed.

[0007] In the prior art, patent document CN208779123U provides a remote monitoring LNG tank with automatic loading and unloading function, which monitors the pressure, liquid level and position information of the LNG tank through wireless transmission, but the use of vehicle-mounted power supply causes the problem of unstable power supply for long-term continuous loading of LNG, and the use of electric valves causes the problem of electrical explosion prevention or large volume that cannot be installed in the LNG automobile tank truck operation box.

[0008] In the prior art, patent document CN210652842U provides a low-temperature liquid transport truck rear operation box, which improves the anti-impact capability of the operation box by using a folded edge structure, side plate stiffeners, door plate stiffeners and folded edge beams, but this method cannot solve the problems of automatic valve control and accidental leakage remote closing operation box shut-off valve during LNG loading and overloading.

[0009] In the prior art, patent document CN216942581U provides a tank-type LNG low-temperature liquid transport semi-trailer rear operation box, which protects the internal components of the operation box from damage by setting a protection mechanism, but it also cannot solve the problems of automatic valve control and accidental leakage remote closing operation box shut-off valve during LNG loading and overloading.

[0010] In the prior art, patent document CN217109129U provides a LNG loading and unloading interlock control device, which increases an electromagnetic valve between the vehicle-mounted gas source and the LNG tank truck pneumatic valve to control the pneumatic valve communication gas source loop, but the tank truck self-contained gas source pressure is insufficient, making it difficult to meet the automatic control requirements of the pneumatic valve in the operation box.

[0011] Therefore, during LNG loading and unloading operations, the loading personnel need to manually operate the valve on site, which not only reduces the efficiency of loading and unloading, but also makes it more prone to valve misoperation. In addition, if the flange leaks or even falls off, the loading operator must manually close the emergency shutdown valve gas source in the operation box to completely close the emergency shutdown valve and prevent continuous leakage of LNG in the tank truck. As a result, the above process poses a risk of frostbite for the operator who comes into contact with low-temperature LNG, and even if the emergency shutdown valve in the operation box cannot be quickly shut off, it may lead to a large amount of LNG leakage, posing a significant risk of explosion.

[0012] To this end, the prior art needs to provide an LNG tank truck automatic operation box and a valve automatic control system thereof to solve the problems of easy misoperation of manual operation of LNG loading and unloading and low safety of emergency shutdown system in emergency. SUMMARY

[0013] The present application aims to provide an LNG tank truck automatic operation box and a valve automatic control scheme thereof to solve the problems of easy misoperation of manual operation of LNG loading and unloading and low safety of emergency shutdown system in emergency.

[0014] To solve the above technical problems, the present application provides a tank truck operation box control system for LNG loading and unloading site, comprising: a tank body; a liquid phase pipeline having an upper liquid inlet pipeline in communication with the top of the tank body and a lower liquid inlet pipeline in communication with the bottom of the tank body; a gas phase pipeline in communication with the top of the tank body; and a control device, which, during LNG loading, first controls the passage of the upper liquid inlet pipeline and the disconnection of the lower liquid inlet pipeline to complete the pre-cooling operation of the LNG tank, the loading arm pipeline and the box pipeline realized by the loading arm connected to the tank truck operation box, and then controls the passage of the lower liquid inlet pipeline and the disconnection of the upper liquid inlet pipeline to complete the formal loading operation realized by the loading arm, wherein when an abnormal pressure in the gas phase pipeline is detected, the passage of the gas phase pipeline is controlled.

[0015] Preferably, the gas phase pipeline comprises a gas phase stop valve and a gas phase emergency shutdown valve arranged between the gas phase stop valve and the tank body, and the control device is further configured to control the gas phase stop valve and the gas phase emergency shutdown valve to open when the pressure in the gas phase pipeline exceeds a preset first level gas phase pipeline pressure threshold value and does not reach a preset second level gas phase pipeline pressure threshold value, the second level gas phase pipeline pressure threshold value being greater than the first level gas phase pipeline pressure threshold value.

[0016] Preferably, the tank truck operation box control system further comprises an emptying pipeline, and the gas phase pipeline further comprises at least two gas phase emergency emptying valves, a first end of a first gas phase emergency emptying valve is hung on a pipeline between the gas phase stop valve and the gas phase emergency shutdown valve, a second end of the first gas phase emergency emptying valve is connected to the emptying pipeline, a first end of a second gas phase emergency emptying valve is hung on a pipeline between the gas phase emergency shutdown valve and the gas phase pipeline inlet, and a second end of the second gas phase emergency emptying valve is connected to the emptying pipeline, and the control device is further configured to control the first gas phase emergency emptying valve and / or the second gas phase emergency emptying valve to open according to the degree of pressure exceeding when the pressure in the gas phase pipeline exceeds the second level gas phase pipeline pressure threshold value.

[0017] Preferably, the emptying pipeline is configured in an arc shape, and the tank operation box control system further comprises a flame arrester arranged at the end of the emptying pipeline.

[0018] Preferably, the upper liquid inlet pipeline and the lower liquid inlet pipeline form a same liquid phase pipeline inlet, 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, and 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: controlling the upper liquid inlet stop valve to open, and injecting raw materials into the tank by the loading arm through the upper liquid inlet pipeline; when it is detected that the tank liquid inlet time reaches a preset specified precooling time or the liquid inlet amount reaches a preset specified precooling liquid inlet amount, controlling the lower liquid inlet stop valve and the lower liquid inlet emergency shut-off valve to open, and simultaneously controlling the upper liquid inlet stop valve to close.

[0020] Preferably, the liquid phase pipeline further comprises a liquid phase emergency emptying valve, a first end of the liquid phase emergency emptying valve is hung on the pipeline between the lower liquid inlet emergency shut-off valve and the tank, and a second end of the liquid phase emergency emptying valve is connected with the emptying pipeline.

[0021] Preferably, the tank operation box control system further comprises a pressurizing pipeline in communication with the top of the tank, the pressurizing pipeline is provided with a pressurizing pipeline stop valve, a pressurizing pipeline emergency shut-off valve and a safety valve arranged on the pipeline between the pressurizing pipeline stop valve and the tank, a first end of the safety valve is hung on the pipeline between the pressurizing pipeline stop valve and the pressurizing pipeline emergency shut-off valve, and a second end of the safety valve is connected with the emptying pipeline.

[0022] Preferably, the control device comprises: a vehicle-mounted control module for controlling the loading process according to sensing information at different positions in each pipeline and tank; a gas source control module for controlling the power of different position valves in each pipeline under the control of the vehicle-mounted control module, wherein the gas source control module comprises: a first gas source assembly for specifying the opening and closing state of a shutoff valve in each pipeline under the control of the vehicle-mounted control module; a second gas source assembly for specifying the opening and closing state of an emergency cut-off valve in each pipeline under the control of the vehicle-mounted control module; a third gas source assembly for specifying the opening and closing state of a vent valve 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, and used for controlling the on-off state between the corresponding gas source assembly and a gas source inlet under the control of the vehicle-mounted control module; and a gas source inlet valve connected with the first control ball valve, the second control ball valve and the third control ball valve.

[0023] Preferably, the vehicle-mounted control module is further used for collecting pressure data in the gas phase pipeline, pressure data in the tank, gas source inlet pressure data, tank liquid level data and tank vacuum degree data in real time, and dynamically detecting the collected real-time data, so as to perform sound and light alarm when abnormal data is detected, wherein the vehicle-mounted control module is powered by a tank static grounding detector module and obtains tank static grounding state information in real time.

[0024] In another aspect, the embodiment of the present application provides a loading and unloading mechanism for an LNG loading and unloading site, comprising: the tank operation box control system as described above; and a loading arm system connected with the tank operation box control system.

[0025] In addition, the embodiment of the present application further provides a tank operation box control method for an LNG loading and unloading site, which is implemented according to the tank operation box control system as described above, wherein the tank operation box control method comprises: in the process of loading LNG, the control device first completes the pre-cooling operation of an LNG tank, a loading arm pipeline and a box pipeline by the loading arm connected with the tank operation box through passage control of an upper liquid inlet pipeline in a liquid phase pipeline and shutoff control of a lower liquid inlet pipeline in the liquid phase pipeline; and the control device completes the formal loading operation by the loading arm through passage control of the lower liquid inlet pipeline and shutoff control of the upper liquid inlet pipeline, wherein when an abnormal pressure in a gas phase pipeline is detected, passage control is performed on the gas phase pipeline connected with the top of the tank.

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

[0027] The application provides a tank truck operation box control system and method for an LNG loading and unloading site. The system and method comprise an operation box body, a liquid phase pipeline, a gas phase pipeline, a pressurizing pipeline and a control device. The gas phase / liquid phase pipeline is provided with a manual / pneumatic integrated exhaust valve / liquid inlet valve and a manual / pneumatic integrated emergency shut-off valve. The system adopts nitrogen gas for site purging of the LNG station as an external compressed gas source. 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 is realized through a vehicle-mounted PLC module to control an electromagnetic valve assembly. The vehicle-mounted PLC is powered by a static grounding detector module. The application can realize automatic control of valves in the LNG operation box and automatic loading and unloading of LNG.

[0028] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent to those skilled in the art from the description, or can be learned by practice of the application. BRIEF DESCRIPTION OF DRAWINGS

[0029] The accompanying drawings are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the application.

[0030] Figure 1 It is a whole structure schematic view of the tank truck operation box control system for the LNG loading and unloading site according to the embodiment of the application.

[0031] Figure 2 It is a specific structure schematic view of the tank truck operation box control system for the LNG loading and unloading site according to the embodiment of the application.

[0032] Figure 3 It is an implementation principle schematic view of the control device in the tank truck operation box control system for the LNG loading and unloading site according to the embodiment of the application.

[0033] Figure 4 It is a circuit control principle schematic view of the tank truck operation box control system for the LNG loading and unloading site according to the embodiment of the application.

[0034] Figure 5The figure shows the overall steps of the tank truck operation box control method for LNG loading and unloading sites according to the embodiments of the present application. DETAILED DESCRIPTION

[0035] The embodiments of the present application will be described in detail below with reference to the accompanying drawings and embodiments, so that the application can be fully understood and implemented. It should be noted that the various embodiments in the present application and the various features in each embodiment can be combined with each other as long as there is no conflict, and the technical solutions formed thereby are within the protection scope of the present application.

[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. Moreover, although the logical order is shown in the flowchart, in some cases, the steps shown or described herein can be executed in an order different from that shown herein.

[0037] The terms used herein are only used to describe specific embodiments and are not intended to limit the exemplary embodiments. Unless the context clearly indicates otherwise, the singular form "a", "an", and "the" as used herein is also intended to include the plural. It should also be understood that the terms "comprise" and / or "include" as used herein specify the presence of stated features, integers, steps, operations, units and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, units, components and / or combinations thereof.

[0038] LNG is a liquid fossil fuel obtained by compressing and cooling natural gas (mainly methane) to its condensation point (-161.5℃) temperature, which has the characteristics of low temperature and easy evaporation. At present, LNG is mainly transported by road using tank trucks. LNG tank trucks mainly include a semitrailer, a tank body, a pipeline system and an operation box, etc. The tank body is composed of a carbon steel outer cylinder and an austenitic stainless steel inner cylinder, and a vacuum layer is provided between the inner cylinder and the outer cylinder. An operation box is provided at the rear of the tank body and the tail of the LNG tank truck, and the operation box is provided with operation valves, instruments and necessary pipeline systems, wherein the pipeline includes a liquid inlet pipeline, a booster pipeline and a gas phase pipeline for loading and unloading, which is used to connect the LNG tank body and the LNG loading arm and its loading control system of the LNG receiving station / LNG liquefaction site.

[0039] To ensure the safety of LNG tank truck loading and unloading, storage and transportation, the tank truck tank body is provided with multiple safety devices, including emergency shut-off system, safety system instrument monitoring system, etc., and is equipped with dry powder extinguisher, guardrail, mudguard, static grounding belt, etc. However, at present, there are many pipelines and valves in the operating box of LNG tank truck, including liquid phase and gas phase pipelines, liquid inlet valve (gas discharge valve), emergency shut-off valve and necessary safety valve. When LNG tank truck loading and unloading operation is carried out, flange connection is needed for connecting the gas phase / liquid phase pipelines of the tank truck with the loading arm, and manual installation / dismounting of the flange and opening or closing of the liquid inlet / exhaust valve are needed.

[0040] In the prior art, patent document CN216202500U provides a new LNG storage tank valve operating box with a quick opening structure, which mainly improves the opening and closing convenience of the operating box door by providing a latch and a hole in the operating box body, but cannot solve the problem of automatic control of the operating valve.

[0041] In the prior art, patent document CN109404655A provides a low-temperature liquefied vehicle fuel tank truck operating box stop valve and pipeline connection leak stop elbow, which mainly processes the LNG high leakage risk parts such as the conveying pipeline, flange and valve in the operating box, effectively seals the elbow connection between the stop valve and the pipeline in the LNG tank truck operating box, but cannot solve the problem of quickly cutting off the flange leakage of the tank truck during on-site loading and unloading.

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

[0043] In the prior art, patent document CN208779123U provides a remote monitoring LNG tank box with automatic loading and unloading function, which monitors the pressure, liquid level and position information of the LNG tank box through wireless transmission, but the use of vehicle-mounted power supply causes the problem of unstable power supply during long-time continuous loading of LNG, and the use of electric valve causes the problem of electrical explosion prevention or large size that cannot be installed in the LNG automobile tank truck operating box.

[0044] In the prior art, patent document CN210652842U provides a low-temperature liquid transport vehicle rear operating box, which improves the anti-impact capability of the operating box by using a folded edge structure, side plate reinforcing ribs, door plate reinforcing ribs and folded edge type cross beams, but this method cannot solve the problems of automatic control of the valve during LNG loading and unloading, and remote closing of the operating box stop valve in case of accidental leakage.

[0045] In the prior art, patent document CN216942581U provides a tank type LNG low temperature liquid transportation semitrailer rear operation box, which protects the internal components of the operation box from damage by setting a protection mechanism, and cannot solve the problems of automatic control of the valve during the LNG loading and passing process and remote closing of the operation box cut valve in case of accidental leakage.

[0046] In the prior art, patent document CN217109129U provides an LNG loading and unloading interlock control device, which increases an electromagnetic valve to control the communication of the pneumatic valve and the gas source circuit between the vehicle-mounted gas source and the LNG tank truck pneumatic valve, which has the problem of insufficient pressure of the tank truck self-provided gas source, which is difficult to meet the automatic control demand of the pneumatic valve in the operation box.

[0047] Therefore, during the LNG loading and unloading operation, the loading operation personnel need to manually operate the valve on site, which not only has low loading and unloading efficiency, but also is more likely to cause valve misoperation; in addition, once the flange leaks or even the flange falls off, the loading operator must manually close the emergency cut valve gas source in the operation box to completely close the emergency cut valve to prevent continuous leakage of LNG in the tank truck. Therefore, the above process has the risk of frostbite of the operator contacting low temperature LNG, and even cannot quickly cut off the emergency cut valve in the operation box, resulting in a large amount of LNG leakage, which has a great risk of combustion and explosion.

[0048] Therefore, the prior art needs to provide an LNG tank truck automatic operation box and a valve automatic control system to solve the problems of easy misoperation of manual operation of the LNG loading and unloading truck and low safety of the emergency cut-off system in the prior art.

[0049] In order to solve the technical problems in the above background art, the embodiments of the present application propose a tank truck operation box control system and method for an LNG loading and unloading site. The system and method can realize automatic control of the LNG tank truck operation box valve; use LNG receiving / liquefaction plant loading station purging nitrogen as a gas source, which is stable; supply power to the vehicle-mounted PLC module through the tank truck electrostatic grounding detector module, and at the same time realize communication between the vehicle-mounted PLC module and the LNG loading control system, realize the whole process automation of the LNG loading system, and improve the overall safety of the loading operation.

[0050] Example One

[0051] Figure 1 The whole structure of the tank truck operation box control system for an LNG loading and unloading site of the embodiments of the present application is shown in the figure. The whole structure of the embodiments of the present application will be described below with reference to the figure. Figure 1 The whole structure of the embodiments of the present application is described.

[0052] As Figure 1As shown, the tanker truck operation box control system of this embodiment includes: tank body 4, liquid phase pipeline 1, gas phase pipeline 2 and control device (not numbered).

[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 tank 4. The lower liquid inlet pipeline is connected to the bottom of tank 4. The gas phase pipeline 2 is connected to the top of tank 4. The control device can be used to control the on / off of the gas phase pipeline 2 and the liquid phase pipeline 1, so as to immediately cut off the internal connection of the liquid phase pipeline 1 and / or the gas phase pipeline 2 in emergency situations (e.g., LNG leakage or continuous leakage inside the tank truck).

[0054] In addition, the control device is used during the LNG feedstock loading process to first perform pre-cooling operations on the LNG transport pipeline, including the LNG tank, loading arm pipeline, and tank body pipeline, by controlling the flow of the upper inlet pipeline and the disconnection of the lower inlet pipeline. Then, by controlling the flow of the lower inlet pipeline and the disconnection of the upper inlet pipeline, the formal loading operation of LNG by the loading arm is completed, thereby achieving automated control of the tank truck control box during loading and unloading operations. The control device is also used to control the flow of the gas phase pipeline when an abnormal pressure is detected in the gas phase pipeline.

[0055] Figure 2 This is a schematic diagram illustrating the specific structure of the tank truck operation box control system for LNG loading and unloading sites, according to an embodiment of this application. See below for reference. Figure 2 The specific structure of the tank truck operation box control system described in the embodiments of the present invention will be explained.

[0056] like Figure 2 As shown, the upper liquid inlet pipe and the lower liquid inlet pipe share the same liquid phase inlet. The first end of the lower liquid inlet pipe serves as the liquid phase inlet, and the second end of the lower liquid inlet pipe is connected to the bottom of the tank 4. The lower liquid inlet pipe includes a lower liquid inlet shut-off valve (which is a manual and pneumatic integrated cryogenic shut-off valve) 101 located near the inlet, and a lower liquid inlet emergency shut-off valve (which is a manual and pneumatic integrated cryogenic shut-off valve) 102 located at the rear end of the lower liquid inlet shut-off valve 101.

[0057] The first end of the upper liquid inlet pipe forms a liquid phase inlet, and the second end of the upper liquid inlet pipe is connected to the top of the tank 4. The upper liquid inlet pipe is equipped with an upper liquid inlet shut-off valve (this shut-off valve is a manual and pneumatic integrated cryogenic shut-off valve) 104 located near the inlet. In addition, the upper liquid inlet pipe also includes an upper liquid inlet check valve 105. The upper liquid inlet check valve 105 is located at the rear end of the upper liquid inlet shut-off valve 104.

[0058] like Figure 2As shown, the inlet end of the liquid phase pipeline (for example, realized by using DN50) 1 is provided with a male quick connector, which is fixed by bolts and can be connected with a female connector 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. The upper liquid inlet pipeline is sequentially provided with an upper liquid inlet manual / pneumatic integrated cryogenic valve (stop valve) 104 and a check valve 105, and is connected with the top 401 of the tank body 4. The lower liquid inlet pipeline is sequentially provided with a lower liquid inlet manual / pneumatic integrated cryogenic valve (stop valve) 101 and a lower liquid inlet emergency shut-off valve 102. The lower liquid inlet pipeline is connected with the bottom of the tank body 4.

[0059] The gas phase pipeline 3 includes a gas phase stop valve (which is a manual and pneumatic integrated cryogenic valve) 301 and a gas phase emergency shut-off valve (which is a manual and pneumatic integrated cryogenic 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 table 308) for collecting the pressure inside the gas phase pipeline in real time is arranged at the rear end of the gas phase emergency shut-off valve 302. The gas phase pressure detection table 308 is used to monitor the pressure inside the gas phase pipeline in real time during loading and unloading operations, and transmit the pressure data inside the gas phase pipeline to the control device. See Figure 4 .

[0061] In actual application, the control device is further used to control the gas phase stop valve 301 and the gas phase emergency shut-off valve 302 to be opened when it is detected that the pressure inside the gas phase pipeline exceeds a preset first gas phase pipeline pressure threshold (for example, 0.6 MPa) and does not reach a preset second gas phase pipeline pressure threshold (for example, 0.8 MPa), so that the gas is discharged through the gas phase pipeline 3. In the embodiment of the present application, the second gas phase pipeline pressure threshold is greater than the first gas phase pipeline pressure threshold.

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

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

[0064] Specifically, the gas phase pipeline 3 further comprises a first gas phase emergency evacuation valve (which is a manual and pneumatic integrated cryogenic valve) 303 and a second gas phase emergency evacuation valve (which is a manual and pneumatic integrated cryogenic valve) 304. The first end of the first gas phase emergency evacuation valve 303 is hung on the pipeline between the gas phase stop valve 301 and the gas phase emergency cut-off valve 302, and the second end of the first gas phase emergency evacuation valve 303 is connected with the evacuation pipeline 310. The first end of the second gas phase emergency evacuation valve 304 is hung on the pipeline between the gas phase emergency cut-off valve 302 and the gas phase pipeline inlet, and the second end of the second gas phase emergency evacuation valve 304 is connected with the evacuation pipeline 310.

[0065] In actual application, the control device is further configured to control the first gas phase emergency evacuation valve and / or the second gas phase emergency evacuation valve to open according to the degree of pressure exceeding when it is detected that the pressure in the gas phase pipeline exceeds the second gas phase pipeline pressure threshold (for example, 0.8 MPa).

[0066] Specifically, in one embodiment, the control device is further configured to control the first gas phase emergency evacuation valve or the second gas phase emergency evacuation valve to open when it is detected that the degree of pressure exceeding reaches the first pressure difference threshold. In another embodiment, the control device is further configured to control the first gas phase emergency evacuation valve and the second gas phase emergency evacuation valve to open simultaneously when it is detected that the degree of pressure exceeding reaches the second pressure difference threshold. The second pressure difference threshold is higher than the first pressure difference threshold.

[0067] Further, the evacuation pipeline 310 is configured in an arc structure. The tank operation box control system further comprises a flame arrester 309 arranged at the end of the evacuation pipeline.

[0068] The gas phase emergency evacuation manual / pneumatic integrated cryogenic valve 303 is installed by welding a tee pipeline between the gas phase emergency cut-off valve 302 and the gas phase pressure detection gauge 308. The gas phase emergency evacuation manual / pneumatic integrated cryogenic valve 303 is connected with the evacuation pipeline 310 of the tank body. The end of the evacuation pipeline 310 is provided with a flame arrester 309 (to ensure the safety of evacuation operation), and the end of the evacuation pipeline 310 is configured in an arc structure pipeline. The gas phase pipeline 3 is connected with the tee valve 305 through a tee pipeline close to the connection of the tank body 4, and two safety valves 306 and 307 are arranged at the two ends of the tee valve 305, respectively, and the safety valves 306 and 307 are connected with the evacuation pipeline 310. The gas phase pipeline inlet is connected with the gas phase manual / pneumatic integrated cryogenic valve (stop valve) 301, and the gas phase evacuation control valve 304 is arranged through a tee pipeline, and the gas phase evacuation control valve 304 is connected with the evacuation pipeline 310 of the tank body.

[0069] Further, the liquid phase pipeline 1 further comprises a liquid phase emergency emptying valve (the emptying valve is a manual and pneumatic integrated cryogenic valve) 103. The first end of the liquid phase emergency emptying valve 103 is connected to the pipeline between the lower liquid inlet emergency cut-off valve 102 and the tank body 4, and the second end of the liquid phase emergency emptying valve 103 is connected to the emptying pipeline 310.

[0070] Specifically, the connecting pipeline between the lower liquid inlet emergency cut-off valve 102 and the tank body 4 is provided with the liquid phase emergency emptying manual / pneumatic integrated cryogenic valve 103 through a three-way pipeline, and the liquid phase emergency emptying manual / pneumatic integrated cryogenic valve 103 is in communication with the tank car tank emptying pipeline 310. In addition, the manual / pneumatic integrated cryogenic valve (stop valve) 101 of the liquid phase pipeline 1 and the lower liquid inlet emergency cut-off valve 102 are provided with a safety valve 106 through a three-way pipeline, which is used to empty the pressurized gas after the LNG gasification between the low-temperature valve (stop valve) 101 and the liquid emergency cut-off valve 102 after the loading of the LNG tank car is completed. The safety valve 106 is in communication with the tank car tank emptying pipeline 310.

[0071] It should be noted that in the embodiment of the present application, all manual / pneumatic integrated cryogenic valves, emergency cut-off valves, emptying valves and other types of valve bodies are connected to the pipeline in a welded form to save the internal space of the tank car.

[0072] In addition, in the embodiment of the present application, the LNG tank car tank body 4 is configured as a double-layer structure. The top of the inner wall 401 is provided with a first pressure gauge 403 and a liquid level (high level) alarm detection gauge 402. The first pressure gauge 403 is used to detect the tank pressure in real time during loading and unloading operation, and transmit the tank pressure data to the control device, as shown in Figure 4 The liquid level (high level) alarm detection gauge 402 is used to detect the tank liquid level in real time during loading and unloading operation, and transmit the tank liquid level data to the control device, as shown in Figure 4 Furthermore, the outer wall of the tank body 4 is also connected with a vacuum degree detection gauge 404. The vacuum degree detection gauge 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 loading and unloading operation, and transmit the vacuum degree data to the control device, as shown in Figure 4 .

[0073] In addition, the tank truck operation box control system further comprises a booster pipeline 2. The booster pipeline 2 is connected to the top of the tank body 4. The booster pipeline 2 is provided with a booster pipeline stop valve (which is a manual and pneumatic integrated cryogenic valve) 201, a booster pipeline emergency cut-off valve (which is a manual and pneumatic integrated cryogenic cut-off valve) 202 arranged on the pipeline between the booster pipeline stop valve 201 and the tank body 4, and a safety valve 203. The first end of the safety valve 203 is hung on the pipeline between the booster pipeline emergency cut-off valve and the booster pipeline emergency cut-off valve 202, and the second end of the safety valve 203 is connected to the emptying pipeline 310.

[0074] As shown in Figure 2 The inlet end of the booster pipeline (for example, realized by using DN50) 2 is provided with a flange, and the booster pipeline 2 is sequentially provided with a booster gas manual / pneumatic integrated cryogenic valve (stop valve) 201 and a booster emergency cut-off valve 202, wherein the booster emergency cut-off valve 202 is connected to the top of the tank body 4. The safety valve 203 is arranged on the pipeline between the booster pipeline emergency cut-off valve 202 and the booster pipeline emergency cut-off valve 202 through a three-way pipeline, and is used to empty the gas with pressure between the low-temperature valve (stop valve) 201 and the emergency cut-off valve 202 after the LNG tank truck unloading is completed. The safety valve 203 is connected to the tank truck tank emptying pipeline 310.

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

[0076] With reference to Figure 3 and Figure 4 The control device according to the embodiment of the present application comprises a vehicle-mounted control (PLC) module 8 and a gas source control module (not numbered).

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

[0078] Further, the gas source control module comprises 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 control the opening and closing 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 control the opening and closing of the emergency cut-off valve in each pipeline under the control of the vehicle control module 8. The third gas source assembly 603 is used to control the opening and closing of the emptying 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; and 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.

[0082] Figure 3 The valve pneumatic control gas circuit connection schematic diagram of the LNG tank car automatic operation box is shown. The stop valves in each pipeline are controlled by 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 booster manual / pneumatic integrated cryogenic valve (stop valve) 201 and the gas manual / pneumatic integrated cryogenic valve (stop valve) 301 used in the liquid phase pipeline 1, the gas phase pipeline 3 and the booster pipeline 2 are controlled by compressed nitrogen gas source and controlled by the first gas source control solenoid valve assembly 601 under the action of the vehicle control module to control the opening and closing of the manual / pneumatic integrated cryogenic valve (stop valve).

[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 inlet emergency cut-off valve 102, the booster emergency cut-off valve 202 and the gas phase emergency cut-off valve 302 are controlled by the second gas source control solenoid valve assembly 602 under the action of the vehicle control module to control the opening and closing of the specified emergency cut-off valve.

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

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

[0086] As shown in Figure 3 , the compressed gas source inlet is provided with a gas source inlet valve body (pressure reducing valve) 5. The rear end of the pressure reducing valve 5 is provided with a second pressure gauge 501. The second pressure gauge 501 is used to detect the gas source inlet pressure in real time during loading and unloading operations, and transmit the gas source inlet pressure data to the control device, as shown in Figure 4 . The rear end of the second pressure gauge 501 is connected to the first, second, and third gas source control solenoid valve assemblies 601, 602, and 603 through stainless steel gas source connecting pipelines (for example, the gas source connecting pipelines are φ8 stainless steel gas pipelines). Between the first to third gas source control solenoid valve assemblies 601 to 603 and the second pressure gauge 501, first, second, and third control ball valves 701, 702, and 703 are respectively installed.

[0087] In the embodiment of the present application, the compressed nitrogen gas source uses compressed nitrogen gas for purging in the LNG station. The tank truck tail operation box is provided with a gas source connector. After the tank truck is parked in the loading station, the fast-connection gas source connector of the loading station is directly connected to the tank truck gas source connector to provide power gas source for opening the manual / pneumatic integrated cryogenic valve (stop valve), emergency shut-off valve, and evacuation valve.

[0088] Each side of the operation box at the tail of the tank truck is provided with a gas source connector, and a ball valve is installed behind the gas source connector to ensure that when the LNG tank truck is parked in the LNG loading station, the nitrogen gas pipeline for purging brought by the loading pry on either side 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 701 to 703 on both sides of the gas source structure are kept closed. After connecting the gas source on either side, the ball valve on the corresponding side is opened. Similarly, when the gas source is disconnected, the ball valve on the corresponding side is closed.

[0089] Figure 4 The circuit control principle diagram of the tank truck operation box control system for the LNG loading and unloading site of the embodiment of the present application is shown inFigure 4 The vehicle-mounted control module is also used for collecting pressure data in the gas phase pipeline, pressure data in the tank, gas source inlet pressure data, tank liquid level data and tank vacuum degree data in real time during loading and unloading operation, and dynamically detecting the collected real-time data, so that sound and light alarm is performed when abnormal data is detected.

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

[0091] The vehicle-mounted control module is used for controlling the opening and closing of the first gas source control electromagnetic valve assembly 601, the second gas source control electromagnetic valve assembly 602 and the third gas source control electromagnetic valve assembly 603. The gas phase pressure detection table 308 (the third pressure table) and the second pressure table 501 transmit the data to the vehicle-mounted control module, and the liquid level meter 401 for detecting the liquid level in the tank, the first pressure table 403 for detecting the pressure in the tank, and the vacuum degree detection table 404 for detecting the vacuum in the tank wall are installed on the tank 4, and the data is transmitted to the vehicle-mounted control module through the 4-20mA signal line, so that the stability of data transmission is ensured through wired connection. In addition, the vehicle-mounted PLC module is provided with a sound and light alarm module to perform sound and light alarm when abnormal data is monitored.

[0092] The vehicle-mounted control module 8 is powered by the tank truck electrostatic grounding detector module 9 in the LNG loading system. The vehicle-mounted PLC module (i.e. the vehicle-mounted control module) 8 in the application is powered by the tank truck electrostatic 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 maximally prevented.

[0093] In actual application, the electrostatic grounding detector module on the tank truck is connected with the explosion-proof plug through a multi-core (for example, 10 cores) connecting line, the explosion-proof plug is connected with the multi-core explosion-proof socket on the vehicle-mounted PLC module 8 through contacts. The tank body is welded with a grounding point, which is connected with the vehicle-mounted PLC module through a grounding wire, so that the connection between the tank truck electrostatic grounding detector module and the tank body is realized through the vehicle-mounted PLC module.

[0094] In addition, the tank truck electrostatic detector module 9 is also directly connected with the control system 10 of the LNG loading arm. In this way, the vehicle-mounted PLC module 8 in the control device in the application can realize communication with the LNG loading arm (control) system 10 through the tank truck electrostatic detector module 9, so that the loading arm system and the tank truck operation box system can understand and master the progress of different operations in the same loading and unloading operation.

[0095] In addition, the vehicle-mounted control module is also used for obtaining the tank car electrostatic grounding state information monitored by the tank car electrostatic grounding detector module in real time, so that the vehicle-mounted control module can know whether the tank car electrostatic grounding state is good (or abnormal) in real time.

[0096] Example Two

[0097] Based on the above embodiment one, the implementation process of the tank car operation box control system of the present application is specifically described as follows.

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

[0099] When starting the LNG loading operation, the main step process is as follows:

[0100] Step one: open the tank car tail operation box door, and the on-site compressed gas source (compressed nitrogen) connector (metal quick plug connector-sub) is inserted into the gas source connector (female) in the tank car operation box to realize the connection of the operation box control gas source. The control device controls the gas source inlet pressure (second pressure gauge 501 reading) to be kept in the range of 0.4-0.7 MPa through the control of the pressure reducing valve 5.

[0101] Step two: the tank car electrostatic grounding detector module is connected with the vehicle-mounted PLC module through the quick plug explosion-proof connector, and the vehicle-mounted PLC module displays that the power is normal. The control device monitors whether the data information sent by the gas phase pressure detection table 308 (third pressure gauge), the second pressure gauge 501, the first pressure gauge 403 and the vacuum degree detection table 404 is normal, otherwise the sound and light alarm of the self-contained sound and light alarm module of the vehicle-mounted PLC module is sounded and lighted, and the tank car tank body instruments and the PLC module need to be detected. When the self-contained sound and light alarm module of the vehicle-mounted PLC module does not sound and light, and the control device monitors that the tank car grounding state of the tank car electrostatic grounding detection module is normal, the control device outputs the indication information of allowing the loading operation, so as to allow the loading.

[0102] Step three: start loading.

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

[0104] Firstly, the upper liquid inlet stop valve 104 is controlled to be opened (the check valve 105 is in the normal open state and the booster pipeline is kept in the closed state), and the tank body is injected with LNG raw materials through the upper liquid inlet pipeline by the loading arm;

[0105] Then, when 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 cut-off valve 102 are controlled to open, and the upper liquid inlet stop valve 104 is controlled to close.

[0106] Specifically, the vehicle-mounted control module in the control device controls the second control ball valve 702 to be always closed, controls the pressurized manual / pneumatic integrated cryogenic valve 201 and the pressurized emergency cut-off valve 202 to be closed, so that the pressurized pipeline remains in a closed state; the vehicle-mounted control module controls the first control ball valve 701 to be always open, controls the first gas source control electromagnetic valve assembly 601 to open the upper liquid inlet manual / pneumatic integrated cryogenic valve 104, and after the tank truck liquid inlet time is about 5 min or the liquid inlet amount reaches 500-700 kg, the lower liquid inlet manual / pneumatic integrated cryogenic valve 101 and the lower liquid inlet emergency cut-off valve 102 are opened, and at the same time, the liquid inlet manual / pneumatic integrated cryogenic valve 104 is controlled to be closed.

[0107] Next, the third control ball valve 703 is controlled to be always open, and when the gas phase pressure detection table 308 on the gas phase pipeline shows a value exceeding 0.6 MPa, the vehicle-mounted PLC control module controls the second gas source control electromagnetic valve assembly 602 to open the gas phase manual / pneumatic integrated cryogenic valve 301 and the gas phase emergency cut-off valve 302; when the tank gas pressure continues to rise to above 0.8 MPa, the vehicle-mounted PLC control module controls the third gas source control electromagnetic valve assembly 603 to open the gas phase emergency emptying manual / pneumatic integrated cryogenic valve 303 and / or the cryogenic valve 304 according to the pressure exceeding degree, so that the high-pressure gas in the tank is discharged through the emergency emptying control valve 309 and the emptying pipeline 310 under different internal pressure states of the gas phase pipeline.

[0108] In addition, when the pressure in the gas phase pipeline collected in real time by the gas phase pressure detection table 308 is lower than 0.6 MPa, the gas phase emergency emptying manual / pneumatic integrated cryogenic valve 303 and 304 can be selected to be closed.

[0109] Step four: loading is completed.

[0110] The vehicle-mounted PLC control module first controls the lower liquid inlet manual / pneumatic integrated cryogenic valve 101 and the lower liquid inlet emergency cut-off valve 102 to be closed;

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

[0112] The tank truck electrostatic grounding detection module is disconnected from the vehicle-mounted PLC module.

[0113] The gas source is disconnected.

[0114] Close the tank truck operation box door, complete the LNG tank truck loading.

[0115] The valve action sequence described in the above embodiment two cannot be changed. If the gas phase arm / liquid phase arm of the loading site of the LNG receiving station / liquefaction engineering and other site loading systems leaks or even accidentally falls off during the loading process, the low-temperature characteristics of the low-temperature (-162℃) LNG do not allow contact with the loading personnel to prevent personnel from being frozen, and therefore the control device disconnects the nitrogen gas source at the front end of the pressure reducing valve 5 remotely, which can 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 the need for manual on-site manual closing of the emergency shut-off valve of the tank truck operation box, to prevent the loaded LNG from continuing to leak and freezing the operating personnel.

[0116] Example Three

[0117] Based on the tank truck operation box control system provided in the above embodiment one and / or embodiment two, the embodiment of the present application further provides a loading and unloading mechanism for an LNG loading and unloading site. The loading and unloading mechanism comprises: the tank truck operation box control system as described in the above embodiment one and / or embodiment two; and a loading arm system connected with the tank truck operation box control system.

[0118] In this way, by docking the loading arm system with the tank truck operation box control system as described in the embodiment of the present application, the automatic control effect of the entire tank truck loading and unloading operation can be achieved.

[0119] Example Four

[0120] Based on the tank truck operation box control system provided in the above embodiment one and / or embodiment two, the embodiment of the present application further provides a tank truck operation box control method for an LNG loading and unloading site. The tank truck operation box control method is implemented according to the tank truck operation box control system as described above.

[0121] Figure 5 The embodiment of the present application is a whole step diagram of the tank truck operation box control method for an LNG loading and unloading site. As shown in Figure 5 The tank truck operation box control method described in the embodiment of the present application comprises the following steps:

[0122] Step S501, during the loading of the LNG raw material, the control device first controls the passage of the upper liquid inlet pipeline connected with the top of the tank body 4 in the liquid phase pipeline 1 and controls the disconnection of the lower liquid inlet pipeline connected with the bottom of the tank body 4 in the liquid phase pipeline 1 to complete the pre-cooling operation of the LNG tank, the loading arm pipeline and the box pipeline realized by the loading arm docked with the tank truck operation box;

[0123] Step S502, the control device completes the formal loading operation realized by the loading arm by controlling the passage of the lower liquid inlet pipeline and the interruption of the upper liquid inlet pipeline. Wherein, when the pressure in the gas phase pipeline is detected to be abnormal, the passage control is performed on the gas phase pipeline communicated with the top of the tank 4.

[0124] The application discloses a tank truck operation box control system and method for LNG loading and unloading sites. The system and method comprise an operation box, a liquid phase pipeline, a gas phase pipeline, a booster pipeline and a control device. A manual / pneumatic integrated exhaust valve / liquid inlet valve and a manual / pneumatic integrated emergency shut-off valve are arranged on the gas phase / liquid phase pipeline; nitrogen gas on site of an LNG station is used as an external compressed gas source, and 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 are controlled to be opened and closed through a vehicle-mounted PLC module and an electromagnetic valve assembly; a static grounding detector module is used to supply power to the vehicle-mounted PLC module, so that communication between the vehicle-mounted PLC and a matching loading control system (a batch controller or a PLC) is realized while ensuring tank truck grounding. The application can realize automatic control of valves in the LNG operation box and automatic loading and unloading of LNG, and in an emergency (for example, tank truck low-temperature LNG leakage), the emergency shut-off valve in the tank truck operation box is quickly closed through a remote mode, so that the risk of personal injury is reduced.

[0125] The above merely describes a preferred embodiment of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the present application, which should be covered by the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

[0126] In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more; the orientations or positional relationships indicated by the terms "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail" and the like are based on the orientations or positional relationships shown in the drawings, and are merely for the purpose of facilitating the description of the present application and simplifying the description, and are not intended to indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", "third" and the like are only for the purpose of description and cannot be understood as indicating or implying relative importance.

[0127] In the description of the application, it should be noted that unless otherwise expressly specified and limited, the terms "connected", "connecting" should be interpreted broadly, for example, can be fixedly connected, can also be detachably connected, or integrally connected; can be mechanically connected, can also be electrically connected; can be directly connected, can also be indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0128] It should be understood that the embodiments disclosed herein are not limited to the specific structures, processing steps or materials disclosed herein, but extend to equivalent alternatives that are obvious to those skilled in the relevant art. It should also be understood that the terms used herein are for the purpose of describing specific embodiments only and are not intended to be limiting.

[0129] The phrase "one embodiment" or "an embodiment" as used throughout this specification means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the application. Therefore, the appearances of the phrase "one embodiment" or "an embodiment" throughout the specification are not necessarily referring to the same embodiment.

[0130] Although the disclosed embodiments of the present application are as described above, the content described is only the embodiments adopted for the purpose of facilitating the understanding of the present application, and is not intended to limit the present application. Any modification and change in the form and details of the embodiments can be made by those skilled in the art without departing from the spirit and scope of the present application. The patent protection scope of the present application shall be subject to the scope defined by the appended claims.

Claims

1. A tank truck operating box control system for an LNG loading and unloading site, characterized by, include: Tank body; The liquid phase pipeline includes an upper liquid inlet pipeline connected to the top of the tank, a lower liquid inlet pipeline connected to the bottom of the tank, and a liquid phase emergency vent valve. The upper liquid inlet pipeline and the lower liquid inlet pipeline form a common liquid phase pipeline inlet. The lower liquid inlet pipeline includes a lower liquid inlet stop valve located near the inlet and a lower liquid inlet emergency shut-off valve located at the rear end of the lower liquid inlet stop valve. The upper liquid inlet pipeline includes an upper liquid inlet stop valve located near the inlet. The first end of the liquid phase emergency vent valve is connected to the pipeline between the lower liquid inlet emergency shut-off valve and the tank, and the second end of the liquid phase emergency vent valve is connected to a vent pipeline. The drain pipe; A gas phase pipeline is connected to the top of the tank. The gas phase pipeline includes a gas phase shut-off valve, a gas phase emergency shut-off valve disposed between the gas phase shut-off valve and the tank, and at least two gas phase emergency vent valves. The first end of the first gas phase emergency vent valve is connected to the pipeline between the gas phase shut-off valve and the gas phase emergency shut-off valve, and the second end of the first gas phase emergency vent valve is connected to the vent pipeline. The first end of the second gas phase emergency vent valve is connected to the pipeline between the gas phase emergency shut-off valve and the inlet of the gas phase pipeline, and the second end of the second gas phase emergency vent valve is connected to the vent pipeline. A control device, during the LNG loading process, first performs pre-cooling operations on the LNG tank, loading arm pipeline, and container pipeline by controlling the flow of the upper inlet pipeline and the disconnection of the lower inlet pipeline, which is achieved by the loading arm connected to the tank truck operating box. Then, it performs the formal loading operation by controlling the flow of the lower inlet pipeline and the disconnection of the upper inlet pipeline, which is achieved by the loading arm. When an abnormal pressure is detected in the gas phase pipeline, the flow of the gas phase pipeline is controlled. The control device includes: The vehicle-mounted control module is used to control the loading process based on sensor information from different locations in each pipeline and tank. A gas source control module, under the control of the vehicle-mounted control module, controls the power of valves at different positions in each pipeline. The gas source control module includes: a first gas source assembly, used to control the opening and closing states of shut-off valves in each pipeline under the control of the vehicle-mounted control module; a second gas source assembly, used to control the opening and closing states of emergency shut-off valves in each pipeline under the control of the vehicle-mounted control module; a third gas source assembly, used to control the opening and closing states of vent 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 located at the front ends of the first, second, and third gas source assemblies, respectively, used to control the on / off state between the corresponding gas source assemblies and the gas source inlet under the control of the vehicle-mounted control module; and a gas source inlet valve body connected to the first, second, and third control ball valves. The vehicle-mounted control module is powered by the tank electrostatic grounding detector module and obtains real-time tank electrostatic grounding state information.

2. The tank operating box control system according to claim 1, characterized in that, The control device is further configured 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-stage gas phase pipeline pressure threshold and does not reach a preset second-stage gas phase pipeline pressure threshold, the second-stage gas phase pipeline pressure threshold being greater than the first-stage gas phase pipeline pressure threshold.

3. The tank operating box control system according to claim 2, characterized in that, The control device is further configured to control the first gas phase emergency vent valve and / or the second gas phase emergency vent valve to open according to the degree of pressure exceeding when it is detected that the pressure in the gas phase pipeline exceeds the second-stage gas phase pipeline pressure threshold.

4. The tank truck operator's box control system of claim 3, wherein, The venting pipeline is configured in an arc shape, and the tank operating box control system further comprises a flame arrester arranged at the end of the venting pipeline.

5. The tank truck operator's box control system of claim 1, wherein, The control device controls the loading operation according to the following procedure: The upper liquid inlet stop valve is controlled to open, and the loading arm injects raw materials into the tank through the upper liquid inlet pipeline; When it is detected that the tank liquid inlet time reaches a preset specified precooling time or the liquid inlet amount reaches a preset specified precooling 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.

6. The tank truck operator's box control system of any one of claims 1-5, wherein, The tank operating box control system further comprises: A pressurizing pipeline in communication with the top of the tank, the pressurizing pipeline being provided with a pressurizing pipeline stop valve, a pressurizing pipeline emergency shut-off valve and a safety valve arranged on the pipeline between the pressurizing pipeline stop valve and the tank, wherein a first end of the safety valve is hung on the pipeline between the pressurizing pipeline stop valve and the pressurizing pipeline emergency shut-off valve, and a second end of the safety valve is connected with the venting pipeline.

7. The tank operating box control system according to claim 1, characterized in that, The vehicle-mounted control module is further configured to collect pressure data in the gas phase pipeline, pressure data in the tank, gas source inlet pressure data, tank liquid level data and tank vacuum degree data in real time, and dynamically detect the collected real-time data, so as to perform audible and visual alarm when abnormal data is detected.

8. A loading and unloading mechanism for an LNG loading and unloading site, characterized by, The tank operating box control system according to any one of claims 1-7; A loading arm system connected with the tank operating box control system. The tank operating box control method is implemented according to the tank operating box control system according to any one of claims 1-7, and the tank operating box control method comprises:

9. A method of controlling a tank truck operating box for an LNG loading and unloading site, characterized by, During the LNG loading process, the control device first completes the precooling operation of the LNG tank, the loading arm pipeline and the box pipeline by the loading arm connected with the tank operating box through passage control of the upper liquid inlet pipeline in the liquid phase pipeline in communication with the top of the tank and circuit interruption control of the lower liquid inlet pipeline in the liquid phase pipeline in communication with the bottom of the tank; ​ The formal loading operation by the loading arm is completed by passage control of the lower liquid inlet line and interruption control of the upper liquid inlet line, and when an abnormal pressure in the gas phase line is detected, the passage control is performed on the gas phase line communicating with the top of the tank.

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