Loading arm control system and method for LNG loading and unloading place

Abstract

The invention discloses a loading arm control system and method for an LNG loading and unloading place. The loading arm control system comprises a stand column; the gas-phase arm is arranged at the upper end of the stand column, the liquid-phase arm is arranged below the gas-phase arm, and the gas-phase / liquid-phase arm is used for automatically moving to a gas-phase / liquid-phase pipeline connector in an LNG tank car operation box through an internal servo motor assembly system; the valve body power device is used for providing power for opening and closing actions of the valve bodies in the gas-phase arm and the liquid-phase arm; the control device is used for controlling the loading arm to automatically move in place and controlling the valve body power device to be started after the loading arm is in butt joint with the tank car operation box, and therefore loading arm leak detection, primary nitrogen replacement, valve opening precooling, loading valve opening and closing and secondary nitrogen replacement operation are sequentially controlled to be completed. According to the method, the loading operation process is simplified, the personnel operation intensity and the misoperation risk are reduced, and meanwhile the LNG loading efficiency is improved.

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 loading arm control system and method for LNG loading and unloading sites. Background Art

[0002] LNG is a liquid fossil fuel that is made by compressing natural gas (mainly methane) and cooling it to its freezing point (-161.5°C). It has the characteristics of low temperature and high volatility. As a clean fossil energy source, LNG is mainly transported by land by tank trucks, whether it is shipped to an LNG receiving station by ship or liquefied by LNG. At an LNG receiving station / LNG liquefaction plant, LNG tank trucks are filled with LNG through an LNG loading system. The LNG loading system includes a loading skid and a loading arm. The loading skid is equipped with flow meters, process control valves, emergency shut-off valves, related pipelines, and control systems, and has automatic control capabilities.

[0003] However, the loading arm in the prior art, the disclosed low-temperature land-based fluid loading and unloading arm (ultra-low-temperature fluid loading and unloading arm), includes a liquid phase arm and a gas phase arm, both of which are provided with manual low-temperature valves, etc., and at the same time, the end of the loading and unloading arm is connected with a loose flange, resulting in the existing loading and unloading arm. During the LNG loading process, the operator needs to manually drag the loading and unloading arm from the loading skid position to the rear position of the LNG tank truck; at the same time, a total of 16 nuts on the liquid phase arm and the gas phase arm flanges are manually tightened to complete the docking of the tank truck and the loading and unloading arm; in addition, before and after LNG loading, the nitrogen injection valve, the drain valve, the liquid inlet valve, etc. need to be manually opened to repeatedly perform nitrogen purging, soap bubble leak detection, pressure relief, precooling, nitrogen purging, etc. on the inside of the loading and unloading arm, and finally remove the flange bolts to complete the LNG loading. The labor intensity of the operators is high and it is easy to make misoperations, resulting in high labor intensity for the operators, time-consuming and labor-intensive flange installation, time-consuming and labor-intensive LNG loading, and low efficiency.

[0004] In the prior art, patent documents CN 112178451 A and CN112178451B respectively provide a semi-automatic tank truck loading and unloading arm and a control method thereof. This method uses a hydraulic cylinder to control the steering of the loading and unloading arm, but a bulky hydraulic drive mechanism is required on site and is not suitable for the reconstruction and application of LNG loading stations with limited space. At the same time, the viscosity, density and other properties of the hydraulic oil are affected by the ambient temperature, which can easily lead to unstable operation of the hydraulic cylinder, making it difficult to achieve precise control of the movement of the loading and unloading arm.

[0005] In the prior art, patent document CN213118461U provides an LNG loading and unloading arm with adjustable height. The height of the LNG loading and unloading arm is adjusted by a limit mechanism, but the LNG loading and unloading arm does not have an automation function.

[0006] In the prior art, patent document CN 215489076 U provides a low-temperature fluid pneumatic assisted loading and unloading arm, which drives the loading and unloading arm to rotate by controlling the extension and retraction of the cylinder through a pneumatic assisted system. However, the movement accuracy of the cylinder when controlling the movement of the loading and unloading arm is low, and it is difficult to achieve accurate docking of the end joint of the loading and unloading arm with the flange of the tank truck, and it is difficult to fundamentally improve the loading and unloading efficiency.

[0007] In the prior art, patent document CN211315763U provides a low-temperature fluid loading and unloading arm, in which an anti-instability device is installed between the column and the rotating arm. Although it solves the problem of the outrigger arm naturally sagging due to gravity during loading and unloading, the loading and unloading arm still needs to be dragged manually, which makes it difficult to reduce the intensity of manual operation.

[0008] In the prior art, patent document CN214744981U provides the most popular intelligent LNG tank truck loading and unloading skid. The crane pipe adopts gas phase airbag valve and liquid phase airbag valve. There is a defect that the valve cannot be closed in the event of an unexpected failure of the control gas source. At the same time, the crane pipe still needs to be manually opened and retracted, and the automation of LNG loading cannot be realized.

[0009] In the prior art, patent document CN111637361A provides an automated loading and unloading device based on low-temperature skid loading, which manually drags the loading and unloading arm and uses flanges to connect the loading and unloading arm and the tank truck, resulting in low loading efficiency.

[0010] In summary, the manual operation of the loading and unloading arms in existing LNG receiving stations / liquefaction plants and the low motion control accuracy have severely limited the loading rate of LNG tank trucks and affected the operating efficiency of the LNG receiving stations / liquefaction plants. At the same time, manual misoperation, loose flange connections, and failure to detect loose seals during soap liquid leak detection can easily lead to LNG leakage and even major explosion risks.

[0011] Therefore, the prior art needs to provide an efficient and high-precision LNG automatic loading arm and a safety control method thereof, so as to solve the problems of low LNG loading efficiency and low motion control accuracy in the prior art, and at the same time reduce the manual labor intensity at the LNG loading site. Summary of the invention

[0012] The purpose of the present invention is to provide an efficient and high-precision LNG automatic loading arm and a safety control method thereof, so as to solve the problem of low LNG loading efficiency in the prior art and reduce the manual labor intensity at the LNG loading site.

[0013] In order to solve the above technical problems, an embodiment of the present invention provides a loading arm control system for an LNG loading and unloading site, comprising: a column; a gas phase arm arranged at the upper end of the column and a liquid phase arm arranged below the gas phase arm, the gas phase arm / the liquid phase arm is used to automatically move to the gas phase / liquid phase pipeline interface in the LNG tank truck operating box by using the internal servo motor component system; a valve body power device, which is used to provide power for switching actions to each valve body in the gas phase arm and the liquid phase arm; a control device, which is used to control the automatic movement of the loading arm into position, and after the loading arm is docked with the tank truck operating box, control the start-up of the valve body power device, thereby controlling the completion of the loading arm leak detection, initial nitrogen replacement, valve opening precooling, loading switch valve and secondary nitrogen replacement operations in sequence.

[0014] Preferably, the gas phase arm / the liquid phase arm comprises: an arm body, which has an inner arm, an outer arm and an outer arm extension; a servo motor assembly system, which includes three sets of servo motor assemblies, the first servo motor assembly is used to control the movement of the inner arm relative to the column, the second servo motor assembly is used to control the movement of the outer arm relative to the inner arm, and the third servo motor assembly is used to control the movement of the outer arm extension relative to the outer arm; a valve body assembly, which includes a cut-off valve arranged on the outer arm, an injection valve hung at the rear end of the cut-off valve and an exhaust valve hung at the rear end of the injection valve, and the injection valve is also respectively connected to the valve body power device; a dry joint installed at the tail end of the outer arm extension, which is used to realize the pipeline docking of the loading arm and the tank truck operating box.

[0015] Preferably, the gas phase arm / the liquid phase arm also includes: a first spring cylinder assembly respectively connecting the starting end of the outer arm with the cut-off valve; and a second spring cylinder assembly respectively connecting the starting end of the outer arm extension arm with the front end of the dry joint.

[0016] Preferably, the control device implements control of the operation of leak detection on the loading arm according to the following process: after the loading arm is docked with the tank truck body, the pressure in the input pipeline between the valve body power device and the gas injection valve is monitored by controlling the valve body power device to start, and whether the pressure in the input pipeline reaches a preset nitrogen injection pressure threshold. If so, proceed to the next step; control the gas injection valves in the gas phase arm and the liquid phase arm to open and maintain a first preset time, and then control the gas injection valves to close; monitor the pressure in the pipe at the end of the outer arm in the gas phase arm and the liquid phase arm, and determine whether the internal pressure of the gas phase arm and the liquid phase arm drops within a preset gas source detection time period based on the pressure in the arm pipeline. If not, control the drain valves in the gas phase arm and the liquid phase arm to open and maintain a second preset time, and then control them to close. If they drop, output a prompt message for checking the joint connection and gas source.

[0017] Preferably, the control device controls the initial nitrogen replacement operation according to the following process: the control device controls the gas injection valves in the gas phase arm and the liquid phase arm to open and maintain the second preset time, and then controls the gas injection valves to close; repeating the previous step.

[0018] Preferably, the control device implements control of the valve opening precooling operation according to the following process: control the shut-off valves in the gas phase arm and the liquid phase arm to open; output prompt information for instructing to open the liquid inlet valve on the LNG tank truck and to open the gas phase arm valve, so as to start loading through the loading arm, and LNG slowly enters the liquid phase arm through the loading skid pipeline, so as to enter the LNG tank truck storage tank after LNG passes through the loading arm liquid phase arm and the upper liquid inlet pipeline in the tank truck operating box, thereby precooling the loading arm pipeline and the LNG tank truck, so that the valve opening precooling operation ends after the precooling operation lasts for a preset precooling time, and the preset precooling time is 5-10 minutes.

[0019] Preferably, the control device controls the operation of the loading switch valve according to the following process: outputting prompt information for instructing to open the lower liquid inlet valve and close the upper liquid inlet valve of the LNG tank truck, thereby formally loading the vehicle through the loading arm; calculating the actual total loading volume of LNG according to the liquid LNG loading mass flow rate, and when the actual total loading volume of LNG reaches a preset total loading volume, controlling the shut-off valves in the gas phase arm and the liquid phase arm to close.

[0020] Preferably, the control device controls the operation of the secondary nitrogen replacement according to the following process: control the drain valves in the gas phase arm and the liquid phase arm to open; control the gas injection valves in the gas phase arm and the liquid phase arm to open and maintain the first preset time, and then control the gas injection valves to close; repeat the previous step twice; output a prompt message for indicating the disconnection of the loading arm and the tank truck operating box.

[0021] Preferably, the column includes: a column body; a column base plate arranged at the bottom of the column body; a liquid phase arm mounting member arranged on the side wall of the column body, which includes a liquid phase arm upper fixing member and a liquid phase arm lower fixing member; a gas phase arm mounting member arranged on the side wall of the column body, and the gas phase arm mounting member is installed above the liquid phase arm mounting member, wherein the gas phase arm mounting member includes a gas phase arm upper fixing member and a gas phase arm lower fixing member, wherein the spacing between the upper fixing member and the lower fixing member is 460 mm, and the spacing between the gas phase arm lower fixing member and the liquid phase arm upper fixing member is 280 mm.

[0022] Preferably, the valve body power device includes: a power gas source, which is used to provide power gas source to each valve body in the gas phase arm and the liquid phase arm; an air source purge device, which is used to provide air source purge power that meets certain pressure conditions to the gas injection valves in the gas phase arm and the liquid phase arm.

[0023] 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 loading arm control system as described above; and a tank truck detection box connected to the loading arm control system.

[0024] In addition, an embodiment of the present invention further provides a loading arm control method for an LNG loading and unloading site, and the loading arm control method is implemented according to the loading arm control system as described above, wherein the loading arm control method includes: a control device controls the automatic movement of the loading arm into position, so that the gas phase arm arranged at the upper end of the column and the liquid phase arm arranged below the gas phase arm respectively use the internal servo motor component system to automatically move to the gas phase / liquid phase pipeline interface in the LNG tank truck operating box; after the loading arm is docked with the tank truck operating box, the start-up of the valve body power device is controlled, and the valve body power device is used to provide power for switching actions to each valve body in the gas phase arm and the liquid phase arm; the control device controls the completion of the loading arm leak detection, initial nitrogen replacement, valve opening pre-cooling, loading switch valve and secondary nitrogen replacement operations in sequence.

[0025] Compared with the prior art, one or more embodiments of the above scheme may have the following advantages or beneficial effects:

[0026] The present invention proposes a loading arm control system and method for LNG loading and unloading sites. The system and method include a column, a gas phase arm, a liquid phase arm, a nitrogen purge system and a control device. The gas phase arm and the liquid phase arm have the same structure, both including an inner arm assembly and an outer arm assembly, and 3 sets of explosion-proof servo motor assemblies; the outer arm assembly includes a fixing, 2 sets of spring cylinder assemblies and their connectors, a rotary joint, a manual / pneumatic integrated low-temperature emergency shut-off valve, a manual / pneumatic integrated nitrogen injection valve, a manual / pneumatic integrated drain valve, a gear transmission assembly, a pull-off valve, a quick dry joint, and a pressure sensor assembly. When the LNG tank truck is loaded, the first to third servo motor assemblies are directly controlled by the PLC controller in the LNG loading station to drive the loading arm to automatically move to the rear of the tank truck, and the operator pushes the dry joint handle to complete the connection between the loading arm and the corresponding gas phase pipe / liquid phase pipe of the tank truck; the PLC control of the LNG loading system automatically detects the purge nitrogen gas source pressure and the power gas source pressure to ensure that the nitrogen purge system is fault-free, and the nitrogen injection valve automatically fills nitrogen, and the low-temperature pressure sensor installed on the loading arm pipe section automatically detects the pressure in the arm and uploads it to the on-site PLC control system. The present invention can realize the functions of automatic movement of the loading arm into position, leak detection, valve opening, precooling, loading, valve closing and replacement, simplify the loading operation process, reduce the work intensity of personnel and the risk of misoperation, and improve the efficiency of LNG loading. In addition, in the event of an accidental LNG leak, the manual / pneumatic integrated emergency shut-off valve of the loading arm is closed remotely, quickly and automatically to reduce the residual LNG leakage in the arm space, and reduce the risk of low-temperature frostbite and LNG explosion of the operator.

[0027] 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

[0028] 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:

[0029] Figure 1 This is a schematic diagram of the overall structure of a loading arm control system for an LNG loading and unloading site according to an embodiment of the present application.

[0030] Figure 2 It is a front view of the loading arm structure in the loading arm control system used in the LNG loading and unloading site according to an embodiment of the present application.

[0031] Figure 3 It is a top view of the loading arm structure in the loading arm control system used in the LNG loading and unloading site according to an embodiment of the present application.

[0032] Figure 4 It is a side view of the loading arm structure in the loading arm control system used in the LNG loading and unloading site according to an embodiment of the present application.

[0033] Figure 5 This is a schematic diagram of the component joints of the nitrogen injection valve and the exhaust valve in the loading arm control system used in the LNG loading and unloading site according to an embodiment of the present application.

[0034] Figure 6 This is a schematic structural diagram of a column assembly in a loading arm control system for an LNG loading and unloading site according to an embodiment of the present application.

[0035] Figure 7 This is a schematic structural diagram of an explosion-proof servo motor assembly in a loading arm control system for an LNG loading and unloading site according to an embodiment of the present application.

[0036] Figure 8 This is a schematic diagram of the specific structure of a loading arm control system for an LNG loading and unloading site according to an embodiment of the present application.

[0037] Fig. 9 This is a workflow diagram of the implementation process of the loading arm control system for the LNG loading and unloading site according to an embodiment of the present application.

[0038] Fig.10 It is a schematic diagram of the overall steps of the loading arm control method for LNG loading and unloading site according to an embodiment of the present application. DETAILED DESCRIPTION

[0039] 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.

[0040] 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.

[0041] 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.

[0042] LNG is a liquid fossil fuel that is made by compressing natural gas (mainly methane) and cooling it to its freezing point (-161.5°C). It has the characteristics of low temperature and high volatility. As a clean fossil energy source, LNG is mainly transported by land by tank trucks, whether it is shipped to an LNG receiving station by ship or liquefied by LNG. At an LNG receiving station / LNG liquefaction plant, LNG tank trucks are filled with LNG through an LNG loading system. The LNG loading system includes a loading skid and a loading arm. The loading skid is equipped with flow meters, process control valves, emergency shut-off valves, related pipelines, and control systems, and has automatic control capabilities.

[0043] However, the loading arm in the prior art, the disclosed low-temperature land-based fluid loading and unloading arm (ultra-low-temperature fluid loading and unloading arm), includes a liquid phase arm and a gas phase arm, both of which are provided with manual low-temperature valves, etc., and at the same time, the end of the loading and unloading arm is connected with a loose flange, resulting in the existing loading and unloading arm. During the LNG loading process, the operator needs to manually drag the loading and unloading arm from the loading skid position to the rear position of the LNG tank truck; at the same time, a total of 16 nuts on the liquid phase arm and the gas phase arm flanges are manually tightened to complete the docking of the tank truck and the loading and unloading arm; in addition, before and after LNG loading, the nitrogen injection valve, the drain valve, the liquid inlet valve, etc. need to be manually opened to repeatedly perform nitrogen purging, soap bubble leak detection, pressure relief, precooling, nitrogen purging, etc. on the inside of the loading and unloading arm, and finally remove the flange bolts to complete the LNG loading. The labor intensity of the operators is high and it is easy to make misoperations, resulting in high labor intensity for the operators, time-consuming and labor-intensive flange installation, time-consuming and labor-intensive LNG loading, and low efficiency.

[0044] In the prior art, patent documents CN 112178451 A and CN112178451B respectively provide a semi-automatic tank truck loading and unloading arm and a control method thereof. This method uses a hydraulic cylinder to control the steering of the loading and unloading arm, but a bulky hydraulic drive mechanism is required on site and is not suitable for the reconstruction and application of LNG loading stations with limited space. At the same time, the viscosity, density and other properties of the hydraulic oil are affected by the ambient temperature, which can easily lead to unstable operation of the hydraulic cylinder, making it difficult to achieve precise control of the movement of the loading and unloading arm.

[0045] In the prior art, patent document CN213118461U provides an LNG loading and unloading arm with adjustable height. The height of the LNG loading and unloading arm is adjusted by a limit mechanism, but the LNG loading and unloading arm does not have an automation function.

[0046] In the prior art, patent document CN 215489076 U provides a low-temperature fluid pneumatic assisted loading and unloading arm, which drives the loading and unloading arm to rotate by controlling the extension and retraction of the cylinder through a pneumatic assisted system. However, the movement accuracy of the cylinder when controlling the movement of the loading and unloading arm is low, and it is difficult to achieve accurate docking of the end joint of the loading and unloading arm with the flange of the tank truck, and it is difficult to fundamentally improve the loading and unloading efficiency.

[0047] In the prior art, patent document CN211315763U provides a low-temperature fluid loading and unloading arm, in which an anti-instability device is installed between the column and the rotating arm. Although it solves the problem of the outrigger arm naturally sagging due to gravity during loading and unloading, the loading and unloading arm still needs to be dragged manually, which makes it difficult to reduce the intensity of manual operation.

[0048] In the prior art, patent document CN214744981U provides the most popular intelligent LNG tank truck loading and unloading skid. The crane pipe adopts gas phase airbag valve and liquid phase airbag valve. There is a defect that the valve cannot be closed in the event of an unexpected failure of the control gas source. At the same time, the crane pipe still needs to be manually opened and retracted, and the automation of LNG loading cannot be realized.

[0049] In the prior art, patent document CN111637361A provides an automated loading and unloading device based on low-temperature skid loading, which manually drags the loading and unloading arm and uses flanges to connect the loading and unloading arm and the tank truck, resulting in low loading efficiency.

[0050] In summary, the manual operation of the loading and unloading arms in existing LNG receiving stations / liquefaction plants and the low motion control accuracy have severely limited the loading rate of LNG tank trucks and affected the operating efficiency of the LNG receiving stations / liquefaction plants. At the same time, manual misoperation, loose flange connections, and failure to detect loose seals during soap liquid leak detection can easily lead to LNG leakage and even major explosion risks.

[0051] Therefore, the prior art needs to provide an efficient and high-precision LNG automatic loading arm and a safety control method thereof, so as to solve the problems of low LNG loading efficiency and low motion control accuracy in the prior art, and at the same time reduce the manual labor intensity at the LNG loading site.

[0052] In order to solve the technical problems in the above-mentioned background technology, the embodiment of the present application proposes a loading arm control system and method for LNG loading and unloading sites. The system and method drive the gear transmission assembly on the loading arm to move through an explosion-proof servo motor assembly, accurately control the horizontal and up and down movement of the inner arm, outer arm and dry joint installation pipe of the loading arm, and are not affected by the temperature and humidity of the external environment and the compressed gas source; using LNG dry joints, there is no need to manually tighten the bolts, and at the same time, a spring cylinder assembly balance mechanism is designed at the front end of the dry joint, which can easily adjust the height of the dry joint to meet the needs of different vehicle models and conditions. Quickly connect / disconnect the loading arm and tank truck; automatically collect the gas source pressure of the nitrogen purge system to prevent accidental short circuit of the gas source from causing safety hazards; use PLC to control the solenoid valve to control the manual / pneumatic integrated cryogenic valve, nitrogen injection valve, and drain valve of the loading arm, without the need for manual valve opening and closing, and automatically complete the LNG loading system leak detection, precooling, filling and other operations, thereby improving loading efficiency.

[0053] Embodiment 1

[0054] Figure 1 This is a schematic diagram of the overall structure of a loading arm control system for an LNG loading and unloading site according to an embodiment of the present application. Figure 8 This is a schematic diagram of the specific structure of the loading arm control system for LNG loading and unloading sites according to an embodiment of the present application. Figure 1 and Figure 8 , the overall structure of the loading arm control system described in the embodiment of the present invention is described.

[0055] In an embodiment of the present invention, the loading arm control system includes a column A (see component 1), a gas phase arm B, a liquid phase arm C, a valve body power device D and a control device E. The gas phase arm B is arranged at the upper end of the side wall of the column 1, and the liquid phase arm C is arranged below the gas phase arm B. The gas phase arm B is used to automatically move to the gas phase pipeline interface in the LNG tank truck operation box by using the internal (explosion-proof) servo motor component system. The liquid phase arm C is used to automatically move to the liquid phase pipeline interface in the LNG tank truck operation box by using the internal (explosion-proof) servo motor component system. The valve body power device D is used to provide power for switching actions to each valve body in the gas phase arm and the liquid phase arm (each valve body is a manual / pneumatic integrated valve body).

[0056] The control device E is used to control the automatic movement of the loading arm (including the gas phase arm B and the liquid phase arm C) into position, and after the loading arm is connected to the corresponding pipeline interfaces (gas phase interface and liquid phase interface respectively) in the tank truck operation box, it controls the start-up of the valve body power device D, thereby controlling a series of operations including loading arm leak detection, initial nitrogen replacement, valve opening precooling, loading switch valve and secondary nitrogen replacement in sequence, so as to realize automatic control of the loading arm during loading and unloading operations.

[0057] Figure 2It is a front view of the loading arm structure in the loading arm control system used in the LNG loading and unloading site according to an embodiment of the present application. Figure 3 It is a top view of the loading arm structure in the loading arm control system used in the LNG loading and unloading site according to an embodiment of the present application. Figure 4 It is a side view of the loading arm structure in the loading arm control system used in the LNG loading and unloading site according to an embodiment of the present application.

[0058] like Figure 2-4 and Figure 8 The loading arm of the present invention comprises a gas phase arm B and a liquid phase arm C. The gas phase arm B and the liquid phase arm C have the same structure, and the gas phase arm B is located at the upper end of the liquid phase arm C, and the two arms B and C are installed on the column 1 together.

[0059] The following only takes the gas phase arm as an example to illustrate the specific structure of arms B and C.

[0060] The gas phase arm and the liquid phase arm both include: an arm body, a servo motor assembly system, a valve body assembly and a dry joint 18. The arm body includes: an inner arm (loading arm) 2, an outer arm (loading arm) 3 and an outer arm extension section (outer arm joint pipe section) 4. The servo motor assembly system includes: three sets of servo motor assemblies.

[0061] The first servo motor assembly 6 is connected to the column 1 and the inner arm 2 respectively. The first servo motor assembly 6 is used to control the movement of the inner arm 2 relative to the column 1 (ie, moving in the horizontal and vertical directions) under the control of the control device E.

[0062] The second servo motor assembly 8 is connected to the inner arm 2 and the outer arm 3 respectively. The second servo motor assembly 8 is used to control the movement of the outer arm 3 relative to the inner arm 2 (ie, to move in the horizontal and vertical directions) under the control of the control device E.

[0063] The third servo motor assembly 15 is connected to the outer arm 3 and the outer arm extension 4 respectively. The third servo motor assembly 15 is used to control the movement of the outer arm extension 4 relative to the outer arm 3 (ie, moving in the horizontal and vertical directions) under the control of the control device E.

[0064] The valve body assembly is arranged on the outer arm 3. The valve body assembly specifically includes: a shut-off valve 10 arranged on the outer arm 3 (the shut-off valve is a manual and pneumatic integrated low-temperature emergency shut-off valve), an injection valve 11 (the injection valve is a nitrogen injection valve, and the injection valve is a manual and pneumatic integrated low-temperature nitrogen injection valve) hung at the rear end of the shut-off valve 10, and an exhaust valve 12 (the exhaust valve is a manual and pneumatic integrated low-temperature exhaust valve) hung at the rear end of the injection valve 11. Among them, the injection valve 11 is also connected to the power gas source and the gas source purge device in the valve body power device D through a stainless steel air pipe. The shut-off valve 10 is also connected to the power gas source in the valve body power device D. The exhaust valve 12 is also connected to the power gas source in the valve body power device D.

[0065] In the embodiment of the present invention, each gas injection valve, each exhaust valve and each shut-off valve are pneumatic / manual integrated valves, using the compressed nitrogen gas in the LNG loading and unloading site as the power gas source, and the compressed nitrogen power gas source controls the "on" and "off" through the control device to control the "opening" and "closing" of the corresponding valve body. In addition, the gas injection valve is also connected to the flushing nitrogen gas source in the LNG loading and unloading site through a stainless steel gas pipe.

[0066] In addition, a dry joint 18 is installed at the tail end of the outer arm extension section 4. In actual application, the dry joint 18 is used to achieve the pipeline docking between the loading arms B, C and the tank truck operation box.

[0067] Furthermore, the gas phase arm B and the liquid phase arm C each further include: a first spring cylinder assembly 19 and a second spring cylinder assembly 20. The first spring cylinder assembly 19 connects the starting end of the outer arm 3 to the cut-off valve 10. The second spring cylinder assembly 20 connects the starting end of the outer arm extension arm 4 to the front end of the dry joint 18.

[0068] Specifically, the inlet connector of the loading arm inner arm 2 is fixed on the column 1, and the loading arm inner arm 2 is connected to the loading skid through the first rotary joint 5 and the matching elbow (90° equal diameter elbow DN50) and flange. The first explosion-proof servo motor assembly 6 is installed at the upper end pipe section (DN50) of the first rotary joint 5. The first explosion-proof motor assembly 6 includes: a first bearing sleeve, a gear transmission assembly, a housing and a servo motor, etc. Figure 7 As shown, the first bearing sleeve covers the connecting pipe where the motor assembly 6 is located, and the gear transmission assembly is installed on the first bearing sleeve. The first bearing sleeve drives the DN50 vertical pipe end where the first rotary joint 5 is located to rotate horizontally; the DN50 vertical pipe end is connected to the horizontal stainless steel pipe (φ60) through a right-angle bend pipe, wherein a φ50 steel rod is welded at the top end of the arc of the right-angle bend pipe, and the φ50 steel rod is inserted into the seat bearing on the column 1. For this purpose, the servo motor assembly 6 drives the first bearing sleeve to rotate horizontally by driving the gear transmission assembly.

[0069] In order to improve the strength of the horizontal stainless steel pipe, a fixing plate is welded on the upper end of the horizontal stainless steel pipe; the horizontal section of the horizontal stainless steel pipe is integrated with the DN50 straight pipe through a right-angle elbow (90° equal diameter elbow DN50); the lower end of the DN50 straight pipe is installed with a second rotary joint 7, and the lower end of the second rotary joint 7 is installed with a second explosion-proof servo motor assembly 8. The second explosion-proof servo motor assembly 8 has the same structure as the first explosion-proof motor assembly 6, specifically including: a second bearing sleeve, a gear transmission assembly, a housing and a servo motor. The second bearing sleeve covers the DN50 connecting pipe where the motor assembly 8 is located, and the gear transmission assembly is installed on the second bearing sleeve. The second bearing sleeve drives the DN50 vertical pipe end where the second rotary joint 5 is located to rotate horizontally.

[0070] The head of the outer arm 3 of the loading arm is installed with a third rotary joint 9 through a right-angle elbow DN50 pipe section; the third rotary joint 9 is connected to the second bearing sleeve on the inner arm 2 of the loading arm through a right-angle elbow (90° equal diameter elbow DN50); the main pipeline of the outer arm 3 of the loading arm is a φ60 stainless steel pipe section, and a shut-off valve 10 (the shut-off valve is a manual and pneumatic integrated low-temperature emergency shut-off valve) is installed on the φ60 stainless steel pipe section through a neck butt welding flange; Figure 4 As shown, the cut-off valve 10 is sequentially connected to the right-angle elbow pipe assembly through the neck butt-welding flange, wherein the horizontal section of the pipe assembly is staggered and welded to install a stainless steel pipe (DN15), and the stainless steel pipe is respectively installed with a manual / pneumatic integrated nitrogen injection valve 11 and a manual / pneumatic integrated exhaust valve 12 through the raised face neck butt-welding flange (for example: in case of on-site gas source failure, the valve can be manually closed), see Figure 5 ;like Figure 5 As shown, the rear end of the nitrogen injection valve 11 is connected to the compressed nitrogen pipeline, and the exhaust valve 12 is connected to the BOG pipeline. On the right-angle elbow pipeline at the rear end of the cryogenic emergency shut-off valve 10, an EF-3 type two-valve group is installed, and the two-valve group is used to install a cryogenic pressure sensor 13. Among them, the cryogenic pressure sensor 13 is used to measure the pressure inside the wall in real time, and the test pressure is not less than 1.5MPa. In addition, the cryogenic pressure sensor is electrically connected to the on-site loading arm control PLC module, and can transmit the pressure data in the pipeline before and after loading to the PLC controller in real time, so as to maintain pressure and detect leaks on the loading arm.

[0071] Since the φ60 stainless steel pipe section where the outer arm 4 of the loading arm is located is installed with a manual / pneumatic integrated low-temperature emergency shut-off valve 10, a manual / pneumatic integrated nitrogen injection valve 11, a manual / pneumatic integrated exhaust valve 12, a low-temperature pressure sensor 13, and corresponding nitrogen inlet pipes, exhaust pipes and stainless steel pipes, the counterweight of the outer arm 4 here is relatively large. Therefore, the embodiment of the present invention will install a spring cylinder connector 1 at the horizontal pipeline of the horizontal right-angle bend at the front end of the third rotating joint 9, and install a spring cylinder connector 2 at the rear end of the third rotating joint 9 and the front end of the emergency shut-off valve 10, wherein the first spring cylinder assembly 19 is installed between the spring cylinder connector 1 and the spring cylinder connector 2. In this way, by adding the assistance of the first spring cylinder assembly 19, this spring cylinder can maintain the horizontal state of the loading arm and can hover at any angle.

[0072] Furthermore, the outer arm 3 of the loading arm is connected to the outer arm joint pipe section 4 through the fourth rotary joint 14, the third explosion-proof servo motor assembly 15 and the fifth rotary joint 16. Among them, the fourth rotary joint 14 is installed on the vertical downward pipe section of the right-angle bend at the end of the outer arm 3, and the lower end is connected to the third explosion-proof servo motor assembly 15. The third explosion-proof servo motor assembly 15 also includes: a third bearing sleeve, a gear transmission assembly and a servo motor. The third bearing sleeve covers the DN50 connecting φ60 pipe where the motor assembly 15 is located, and the gear transmission assembly is installed on the third bearing sleeve. The third bearing sleeve drives the fourth rotary joint 14 to achieve horizontal rotation.

[0073] The outer arm joint pipe section 4 is connected to the fifth rotary joint 16 by direct bending. The rear end of the fifth rotary joint 16 is sequentially installed with a breakaway valve 17 and an LNG dry joint 18 through a right-angle bend. In order to control the LNG dry joint to maintain a horizontal state, the embodiment of the present invention welds a spring cylinder connector 3 at the rear end of the third explosion-proof servo motor assembly 15 (i.e., the front end of the fifth rotary joint 16), and welds a spring cylinder connector 4 at the front end of the breakaway valve 17, wherein a second spring cylinder assembly 20 is installed between the spring cylinder connector 3 and the spring cylinder connector 4. The second spring cylinder assembly 20 is used to keep the LNG dry joint in a horizontal state and can be suspended at any angle.

[0074] Specifically, the LNG dry connector is divided into male and female connectors. The male connector of the dry connector is installed at the entrance of the liquid phase pipeline and gas phase pipeline of the LNG tank truck, and the female connector of the dry connector is installed at the tail end of the gas phase arm and liquid phase arm in the loading arm. The interior of the dry connector adopts a valve umbrella top-opening structure. The handle at the female end is pushed by the docking of the male and female connectors to achieve the pipeline connection between the LNG loading arm and the LNG tank truck.

[0075] further, Figure 6The installation diagram of the explosion-proof servo motor assembly 6 is shown. The explosion-proof servo motor 602 fixed on the column 1 drives the gear transmission assembly 601 to rotate, wherein the φ50 steel rod 603 is fixed on the seat bearing 108 of the column 1. All driving gear transmission assemblies are installed with limit plates to prevent the gears from rotating too much. In this way, the loading arm as a whole uses a servo motor to drive the gears to control the steering, running speed and position of the loading arm.

[0076] Figure 6 Schematic diagram of the structure of the column assembly in the loading arm control system for LNG loading and unloading sites according to the embodiment of the present application. Figure 6 As shown, the column 1 described in the embodiment of the present invention includes: a column body 101, a column base plate 102, a liquid phase arm mounting member, and a gas phase arm mounting member.

[0077] The column base plate 102 is arranged at the bottom of the column 101. The liquid phase arm mounting member is arranged on the side wall of the column 101. The liquid phase arm mounting member includes: a liquid phase arm upper fixing member 105 and a liquid phase arm lower fixing member 104. The gas phase arm mounting member is arranged on the side wall of the column 101, and the gas phase arm mounting member is installed above the liquid phase arm mounting member. The gas phase arm mounting member includes: a gas phase arm upper fixing member 107 and a gas phase arm lower fixing member 108.

[0078] Each upper fixing member 105, 107 is provided with a seat bearing 108, which is used to fix a φ50 steel bar to install the corresponding loading arms B, C. In addition, a column bottom plate reinforcement rib 103 is welded on the column bottom plate 102, so that the entire column is installed on the rear end of the LNG loading skid through the column bottom plate using expansion screws.

[0079] In one embodiment, the column height is preferably 2300 mm. The spacing between the lower fixing piece 108 of the gas phase arm and the upper fixing piece 105 of the liquid phase arm is 280 mm. The spacing between each upper fixing piece and its corresponding lower fixing piece is 460 mm (for example: the spacing between the upper fixing piece 107 of the gas phase arm and the lower fixing piece 108 of the gas phase arm is 460 mm; the spacing between the upper fixing piece 105 of the liquid phase arm and the lower fixing piece 104 of the liquid phase arm is 460 mm).

[0080] like Figure 8As shown, the valve body power device D includes: a power gas source and a gas source purge device. The power gas source is used to provide corresponding power gas sources to each valve body in the gas phase arm B and the liquid phase arm C under the control of the control device E, so that each valve body has the power to complete the switching action. The gas source purge device is used to provide gas source purge power that meets certain pressure conditions to the gas injection valves in the gas phase arm B and the liquid phase arm C under the control of the control device E, so as to perform pressure maintenance test on the air tightness of the loading arm pipeline and its flange before LNG loading, replace the air in the loading arm pipeline with nitrogen before loading, and replace the residual LNG and gasified natural gas in the loading arm pipeline with nitrogen after loading.

[0081] The loading arm gas phase arm B and liquid phase arm C are equipped with relatively independent gas source purge devices (such as nitrogen purge devices) and power gas sources. Figure 8 As shown, the control device E described in the embodiment of the present invention includes a PLC controller 21 and a solenoid valve assembly 22 .

[0082] The PLC controller 21 is mainly used to control the motors and valves required in the entire loading and unloading process, so as to complete the control of the automatic movement of the loading arm into position, and the full operation control of the loading arm involved in the loading and unloading process, including the loading arm leak detection, initial nitrogen replacement, valve opening precooling, loading valve switching and secondary nitrogen replacement. The solenoid valve assembly 22 is connected to the PLC controller 21. The solenoid valve assembly 22 is mainly used to specify the switch action of each valve required in the entire loading and unloading process under the control of the above-mentioned PLC controller 21.

[0083] In an embodiment of the present invention, the power gas source is compressed nitrogen, and the gas source pressure is 0.4-0.7MPa. The power gas source is connected to the solenoid valve assembly 22 through a φ8 stainless steel gas pipe. A first pressure reducing valve 23 located at the loading station site is installed between the power gas source and the solenoid valve assembly 22. In addition, a first gas source pressure sensor 24 is connected to the rear end of the first pressure reducing valve 23. The first pressure reducing valve 23 is connected to the solenoid valve assembly 22 through a stainless steel gas pipe. Through the metal hose fixed on the loading arms B and C, the solenoid valve assembly 22 distributes the power gas source to the manual / pneumatic integrated low-temperature emergency shut-off valve 10, the manual / pneumatic integrated nitrogen injection valve 11 and the manual / pneumatic integrated drain valve 12 in the gas phase arm B and the liquid phase arm C respectively. Among them, the power gas distribution of the solenoid valve assembly 22 is controlled by the PLC controller 21, wherein the PLC controller 21 can be installed in the cabinet room of the LNG receiving station or the liquefaction plant, and the solenoid valve assembly 22 can be installed in a flameproof control box and installed near the on-site loading arm. The first gas source pressure sensor 24 is used to detect the compressed nitrogen gas source pressure (ie, the pressure in the power gas source delivery pipeline) in real time, and transmit the gas source pressure data to the PLC controller 21 through the pressure sensor.

[0084] The gas source purge device is provided with purge nitrogen by a compressed nitrogen gas source (gas source pressure 0.4-0.7MPa), and the purge nitrogen gas source is connected to the manual / pneumatic integrated nitrogen injection valve 11 in the gas phase arm of the loading arm and the liquid phase arm of the loading arm through a φ8 stainless steel gas pipe. A second pressure reducing valve 25 located at the loading station site is installed between the purge nitrogen gas source and the nitrogen injection valve 11. The rear end of the second pressure reducing valve 25 is connected to a second gas source pressure sensor 26. Through the metal hose fixed on the loading arms B and C, the gas source purge device distributes the purge nitrogen to the manual / pneumatic integrated nitrogen injection valve 11 corresponding to the gas phase arm of the loading arm and the liquid phase arm of the loading arm. The second gas source pressure sensor 26 is used to detect the compressed nitrogen gas source pressure (i.e., the pressure in the purge gas source delivery pipeline) in real time, and transmit the gas source pressure data to the PLC controller 21 through the pressure sensor.

[0085] In addition, the first to third explosion-proof servo motor assemblies in the loading arms B and C are directly electrically connected to the PLC controller 21, respectively, and are electrically connected to the PLC controller 21 through the master controller (ie, batch controller) in the on-site loading skid.

[0086] Embodiment 2

[0087] Based on the above-mentioned first embodiment, the implementation process of the loading arm control system of the present invention is specifically described below. Fig. 9 This is a workflow diagram of the implementation process of the loading arm control system for the LNG loading and unloading site according to an embodiment of the present application.

[0088] Preparation for loading: After the LNG tank truck stops at the loading position and stands steady, the loader who has eliminated the static electricity on his body opens the operation box at the rear of the tank truck and manually connects the static grounding clamp of the tank truck; after the static grounding connection of the tank truck is completed, pull out the fixing pin of the loading arm fixed in the loading skid position; select the automatic mode on the batch controller and click "Preparation for loading". The control device E servo motor assembly system drives the arm bodies in the gas phase arm B and the liquid phase arm C to move horizontally to the horizontal positions of the gas phase interface and the liquid phase interface corresponding to the tank truck operation box. Specifically, the control device E is used to control the first to third servo motor assemblies to rotate and push the liquid phase arm C and the gas phase arm B to automatically move to the corresponding positions of the LNG tank truck operation box, and manually assist in pushing the LNG dry joint handle, and insert the joint into the corresponding pipeline of the operation box to complete the docking with the male head.

[0089] In one embodiment, the control device E implements the control of the loading arm leakage detection operation according to the following process:

[0090] First, after the loading arm is docked with the tank truck body, the pressure in the input pipeline between the valve body power device and the gas injection valve (i.e., the pressure in the power gas source delivery pipeline and the pressure in the purge gas source delivery pipeline) is monitored by controlling the power gas source and the gas purge device in the valve body power device D to start, and it is judged whether the corresponding preset nitrogen pressure threshold is reached according to the pressure in the input pipeline (i.e., it is judged whether the pressure in the power gas source delivery pipeline and the pressure in the purge gas source delivery pipeline reach the corresponding preset gas injection pressure threshold). If reached, the next step is entered until the corresponding preset gas injection pressure threshold conditions are reached.

[0091] Then, the gas injection valves 11 in the gas phase arm B and the liquid phase arm C are controlled to open and maintain for a first preset time (eg, 10 seconds), and then the gas injection valves 11 are controlled to close.

[0092] Finally, the internal pressure of the outer arm 3 at the end of the gas phase arm B and the liquid phase arm C is monitored, and the internal pressure of the gas phase arm and the liquid phase arm is judged according to the pressure in the arm pipeline to determine whether the internal pressure of the gas phase arm and the liquid phase arm has dropped within the preset gas source detection time period (for example: 30s). If it has not dropped, the exhaust valve 12 in the gas phase arm B and the liquid phase arm C is controlled to open and maintain for a second preset time (for example: 5s), and then controlled to close. If it has dropped, a prompt message for checking the joint connection and the gas source is output.

[0093] For gas source detection and leak detection control, the control device E automatically detects the pressure of the purge and power compressed nitrogen sources. When the purge gas source pressure is greater than 0.6MPa and the power gas source pressure is greater than 0.4MPa, the nitrogen injection valve 11 is opened, and the nitrogen injection valve 11 is controlled to be closed after being maintained for 10s; the low-temperature pressure sensor 13 tests the purge gas source pressure and uploads the test data to the control device E. The control device E detects whether the current purge gas source pressure is still greater than 0.6MPa and whether the current gas source pressure in the loading arm drops within 30s. If so, an automatic voice prompt is used to check the joint connection and gas source; if the gas source pressure in the loading arm is constant and unchanged within 30s, the control device E controls the drain valve to open, and controls it to be closed after being maintained for 5s, thereby deflation of the gas in the loading arm.

[0094] In one embodiment, the control device E implements the control of the initial nitrogen replacement operation according to the following process:

[0095] S1 The control device E controls the gas injection valve 11 in the gas phase arm B and the liquid phase arm C to open and keep it open for a second preset time (e.g., 5s), and then controls the gas injection valve 11 to close;

[0096] S2 repeats the previous step S1 again.

[0097] For the initial nitrogen replacement control, the control device E first controls the nitrogen injection valve 11 to open and hold it for 5 seconds, then controls it to close; then opens the exhaust valve 12 and holds it for 5 seconds, then controls it to close; repeats the control to open the nitrogen injection valve 11 and hold it for 5 seconds, then controls it to close; then repeats the control to open the exhaust valve 11 and hold it for 5 seconds, then controls it to close, thereby completing the nitrogen replacement operation in the gas phase arm and the liquid phase arm.

[0098] In one embodiment, the control device E implements the control of the valve opening precooling operation according to the following process:

[0099] First, the control device E controls the shut-off valves 10 in the gas phase arm B and the liquid phase arm C to open;

[0100] Then, the control device E outputs a prompt message for instructing to open the upper liquid inlet valve of the LNG tanker and to open the gas phase arm valve, so that the loading skid starts loading through the loading arm, and the LNG slowly enters the liquid phase arm through the loading skid pipeline, so that the LNG enters the LNG tanker storage tank after passing through the loading arm liquid phase arm and the upper liquid inlet pipeline in the tanker operation box, thereby precooling the loading arm pipeline and the LNG tanker, so that the precooling operation ends after the duration of the precooling operation reaches the preset precooling time. The preset precooling time is 5-10 minutes.

[0101] For valve opening precooling control, the control device E first controls the shut-off valve 10 in the liquid phase arm and gas phase arm of the loading arm to open, and starts loading. Then, the voice prompts the operator to open the liquid inlet valve on the LNG tanker, and the LNG slowly enters the liquid phase arm of the loading arm through the loading skid pipeline, and enters the LNG tanker storage tank through the loading arm liquid phase arm and the upper liquid inlet pipeline in the tanker operation box, and precools the loading arm pipeline and the LNG tanker. Finally, the real-time liquid LNG mass transmitted by the automatic mass flowmeter on the loading skid enables the control device E to detect in real time after the loading volume of the LNG tanker reaches 500kg (or when the precooling time reaches the preset precooling time), and outputs the indication information of the end of the tanker precooling.

[0102] In one embodiment, the control device E implements the control of the loading valve closing operation according to the following process:

[0103] First, the control device E outputs a prompt message for instructing to open the lower liquid inlet valve and close the upper liquid inlet valve of the LNG tanker, so that the loading of the tanker begins by the loading skid passing through the loading arm;

[0104] Then, the control device E controls the shut-off valves 10 in the gas phase arm B and the liquid phase arm C to close when the gas supply flow rate reaches a preset total loading amount based on the gas supply flow rate monitored in real time.

[0105] For the valve closing control during loading, the control device E firstly prompts the operator to open the lower inlet valve of the LNG tank truck and close the upper inlet valve. At this time, the tank truck starts to load normally. The real-time liquid LNG loading mass flow rate transmitted by the automatic mass flow meter on the loading skid enables the control device E to calculate the actual total loading volume of LNG in real time and complete the detection. After the real-time detection that the actual total loading volume of LNG reaches the preset total loading volume, the control device E controls the closing of the shut-off valve 10 in the liquid phase arm C and the gas phase arm B of the loading arm.

[0106] In one embodiment, the control device E implements the control of the secondary nitrogen replacement operation according to the following process:

[0107] T1 is controlled by the control device E to open the exhaust valves in the gas phase arm B and the liquid phase arm C;

[0108] T2 The control device E controls the gas injection valve 11 in the gas phase arm B and the liquid phase arm C to open and maintain the first preset time (e.g., 10s), and then controls the gas injection valve 11 to close;

[0109] T3 repeats the previous step T2 twice;

[0110] T4 control device E outputs a prompt message for instructing to disconnect the loading arm (dry joint 18) and the tank truck operation box.

[0111] For secondary nitrogen replacement and disconnection control, first control the opening of the nitrogen injection valve in the gas phase arm B and the liquid phase arm C and keep it for 10 seconds and then control it to be closed; then open the drain valve 12 in the gas phase arm B and the liquid phase arm C and keep it for 10 seconds and then control it to be closed; repeat the previous step (open the nitrogen injection valve and then close it after 10 seconds, open the drain valve and then close it after 10 seconds) twice; finally, output a voice prompt message to disconnect the electrostatic grounding clamp of the LNG dry joint and the tank truck, so that after the operator disconnects the tank truck from the loading arm, the tank truck operating box door is closed and the tank truck drives away.

[0112] In addition, if loading continues, the LNG loading arm will automatically and quickly retract, and the tank truck can quickly enter the site for loading without affecting the tank truck's route; after the loading vehicle enters the station and stabilizes, the above steps will be repeated, and the loading system will automatically start exhausting, opening valves, precooling, loading, closing valves, and replacement, etc., to achieve semi-automatic LNG loading. Otherwise, the control device E will control the servo motor assembly to drive the liquid phase arm and the gas phase arm to return to their positions, and the loading is completed.

[0113] The valve action sequence described in the above-mentioned embodiment 2 cannot be changed. If the gas phase arm and / or liquid phase arm of the on-site loading system such as the LNG receiving station / liquefaction plant leaks or even accidentally falls off from the gas phase and / or liquid phase pipeline of the tank truck during loading, the low temperature characteristics of the low temperature (-162°C) LNG do not allow it to contact the loading workers to prevent frostbite. For this reason, the control device E remotely disconnects the compressed nitrogen gas source at the front end of the first pressure reducing valve 23, which can close the emergency shut-off valve 10 corresponding to the liquid phase arm / gas phase arm of the loading arm to prevent the residual LNG inside the loading arm from continuing to leak, without the need to manually close the emergency shut-off valve of the tank truck operating box on site, to prevent the loaded LNG from continuing to leak and frostbite the workers.

[0114] Embodiment 3

[0115] Based on the loading arm 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 loading arm control system as described in the above embodiment 1 and / or embodiment 2; and a tank truck detection box connected to the loading arm control system.

[0116] In this way, by connecting the loading arm control system described in the embodiment of the present invention with the tank truck detection box, the automatic control effect of the whole process operation of the loading arm in the complete tank truck loading and unloading operation can be achieved.

[0117] Embodiment 4

[0118] Based on the loading arm control system provided in the above embodiment 1 and / or embodiment 2, the embodiment of the present invention further provides a loading arm control method for LNG loading and unloading sites. The loading arm control method is implemented according to the loading arm control system as described above.

[0119] Fig.10 Schematic diagram of the overall steps of the loading arm control method for LNG loading and unloading site in the embodiment of the present application. Fig.10 As shown, the loading arm control method described in the embodiment of the present invention includes the following steps:

[0120] Step S1001, the control device E controls the automatic movement of the loading arms B and C, so that the gas phase arm B arranged at the upper end of the column and the liquid phase arm C arranged below the gas phase arm B are automatically moved to the corresponding gas phase and liquid phase pipeline interfaces in the LNG tank truck operation box by using the internal servo motor component system;

[0121] Step S1002: After the loading arms B and C are docked with the tank truck operation box, the valve body power device D is controlled to start, and the valve body power device D is used to provide power for the opening and closing actions of the valve bodies in the gas phase arm B and the liquid phase arm C;

[0122] Step S1003, the control device E sequentially controls to complete the loading arm leak detection, initial nitrogen replacement, valve opening precooling, loading valve switching and secondary nitrogen replacement operations.

[0123] The present invention discloses a loading arm control system and method for LNG loading and unloading sites. The system and method include a column, a gas phase arm, a liquid phase arm, a nitrogen purge system and a control device. The gas phase arm and the liquid phase arm have the same structure, both including an inner arm assembly and an outer arm assembly, and three sets of explosion-proof servo motor assemblies; the outer arm assembly includes a fixing, two sets of spring cylinder assemblies and their connectors, a rotary joint, a manual / pneumatic integrated low-temperature emergency shut-off valve, a manual / pneumatic integrated nitrogen injection valve, a manual / pneumatic integrated drain valve, a gear transmission assembly, a pull-off valve, a quick dry joint, and a pressure sensor assembly. When the LNG tank truck is loaded, the first to third servo motor assemblies are directly controlled by the PLC controller in the LNG loading station to drive the loading arm to automatically move to the rear of the tank truck, and the operator pushes the dry joint handle to complete the connection between the loading arm and the corresponding gas phase pipe / liquid phase pipe of the tank truck; the PLC control of the LNG loading system automatically detects the purge nitrogen gas source pressure and the power gas source pressure to ensure that the nitrogen purge system is fault-free, and the nitrogen injection valve automatically fills nitrogen, and the low-temperature pressure sensor installed on the loading arm pipe section automatically detects the pressure in the arm and uploads it to the on-site PLC control system. The present invention can realize the functions of automatic movement of the loading arm into position, leak detection, valve opening, precooling, loading, valve closing and replacement, simplify the loading operation process, reduce the work intensity of personnel and the risk of misoperation, and improve the efficiency of LNG loading. In addition, in the event of an accidental LNG leak, the manual / pneumatic integrated emergency shut-off valve of the loading arm is closed remotely, quickly and automatically to reduce the residual LNG leakage in the arm space, and reduce the risk of low-temperature frostbite and LNG explosion of the operator.

[0124] 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.

[0125] 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.

[0126] 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.

[0127] 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.

[0128] 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.

[0129] 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 loading arm control system for LNG loading and unloading sites, characterized in that: include: Column; A gas phase arm disposed at the upper end of the column and a liquid phase arm disposed below the gas phase arm, wherein the gas phase arm / the liquid phase arm is used to automatically move to the gas phase / liquid phase pipeline interface in the LNG tank truck operation box by using an internal servo motor component system; A valve body power device, which is used to provide power for switching actions to each valve body in the gas phase arm and the liquid phase arm; The control device is used to control the automatic movement of the loading arm into position, and after the loading arm is docked with the tank truck operation box, control the start-up of the valve body power device, thereby sequentially controlling the completion of the loading arm leak detection, initial nitrogen replacement, valve opening precooling, loading switch valve and secondary nitrogen replacement operations.

2. The loading arm control system according to claim 1, characterized in that: The gas phase arm / the liquid phase arm comprises: An arm body, which comprises an inner arm, an outer arm and an outer arm extension section; A servo motor assembly system, comprising three sets of servo motor assemblies, wherein the first servo motor assembly is used to control the movement of the inner arm relative to the column, the second servo motor assembly is used to control the movement of the outer arm relative to the inner arm, and the third servo motor assembly is used to control the movement of the outer arm extension relative to the outer arm; A valve body assembly, comprising a cut-off valve arranged on the outer arm, an air injection valve connected to the rear end of the cut-off valve, and an exhaust valve connected to the rear end of the injection valve, wherein the air injection valves are also connected to the valve body power device respectively; The dry joint installed at the tail end of the outer arm extension section is used to achieve pipeline docking between the loading arm and the tank truck operating box.

3. The loading arm control system according to claim 2, characterized in that: The gas phase arm / the liquid phase arm also includes: a first spring cylinder assembly respectively connecting the starting end of the outer arm to the cut-off valve; A second spring cylinder assembly connects the starting end of the outer arm extension arm to the front end of the dry joint respectively.

4. The loading arm control system according to claim 2 or 3, characterized in that: The control device implements the control of the loading arm leak detection operation according to the following process: After the loading arm is docked with the tank truck body, the pressure in the input pipeline between the valve body power device and the gas injection valve is monitored by controlling the valve body power device to start, and whether the pressure in the input pipeline reaches the preset nitrogen injection pressure threshold value, if so, proceed to the next step; Controlling the gas injection valves in the gas phase arm and the liquid phase arm to open and maintain for a first preset time, and then controlling the gas injection valves to close; Monitor the pressure inside the tube at the end of the outer arm in the gas phase arm and the liquid phase arm, and determine whether the internal pressure of the gas phase arm and the liquid phase arm drops within a preset gas source detection time period based on the pressure in the arm pipeline. If it does not drop, control the drain valve in the gas phase arm and the liquid phase arm to open and maintain it for a second preset time, and then control it to close. If it drops, output a prompt message to check the joint connection and gas source.

5. The loading arm control system according to claim 4, characterized in that: The control device controls the operation of the initial nitrogen replacement according to the following process: The control device controls the gas injection valves in the gas phase arm and the liquid phase arm to open and maintain the second preset time, and then controls the gas injection valves to close; Repeat the previous step.

6. The loading arm control system according to claim 5, characterized in that: The control device controls the valve opening precooling operation according to the following process: Controlling the shut-off valves in the gas phase arm and the liquid phase arm to open; The output is used to instruct the prompt information to open the upper liquid inlet valve of the LNG tank truck and open the gas phase arm valve, so that loading starts through the loading arm, and LNG slowly enters the liquid phase arm through the loading skid pipeline, so that after LNG passes through the loading arm liquid phase arm and the upper liquid inlet pipeline in the tank truck operation box, it enters the LNG tank truck storage tank, thereby precooling the loading arm pipeline and the LNG tank truck, so that the precooling operation ends after the duration of the precooling operation reaches the preset precooling time, and the preset precooling time is 5-10 minutes.

7. The loading arm control system according to claim 6, characterized in that: The control device controls the operation of the loading switch valve according to the following process: Outputting prompt information for instructing to open the lower liquid inlet valve and close the upper liquid inlet valve of the LNG tanker, so as to officially load the tanker through the loading arm; The actual total loading amount of LNG is calculated according to the loading mass flow of liquid LNG, and when the actual total loading amount of LNG reaches a preset total loading amount, the shut-off valves in the gas phase arm and the liquid phase arm are controlled to be closed.

8. The loading arm control system according to claim 7, characterized in that: The control device controls the secondary nitrogen replacement operation according to the following process: Controlling the drain valves in the gas phase arm and the liquid phase arm to open; Controlling the gas injection valves in the gas phase arm and the liquid phase arm to open and maintain the first preset time, and then controlling the gas injection valves to close; Repeat the previous step twice; Output a prompt message for instructing to disconnect the loading arm and the tank truck operation box.

9. The loading arm control system according to any one of claims 1 to 8, characterized in that: The column comprises: Column; A column base plate disposed at the bottom of the column; A liquid phase arm mounting member disposed on the side wall of the column, comprising an upper liquid phase arm fixing member and a lower liquid phase arm fixing member; A gas phase arm mounting member is arranged on the side wall of the column, and the gas phase arm mounting member is installed above the liquid phase arm mounting member, wherein the gas phase arm mounting member includes a gas phase arm upper fixing member and a gas phase arm lower fixing member, wherein, The distance between the upper fixing part and the lower fixing part is 460 mm, and the distance between the lower fixing part of the gas phase arm and the upper fixing part of the liquid phase arm is 280 mm.

10. The loading arm control system according to any one of claims 1 to 9, characterized in that: The valve body power device comprises: A power gas source, used to provide a power gas source to each valve body in the gas phase arm and the liquid phase arm; The gas source purge device is used to provide gas source purge power that meets certain pressure conditions to the gas injection valves in the gas phase arm and the liquid phase arm.

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

12. A method for controlling a loading arm at an LNG loading and unloading site, characterized in that: The loading arm control method is implemented according to the loading arm control system according to any one of claims 1 to 10, wherein the loading arm control method comprises: The control device controls the automatic movement of the loading arm to the position, so that the gas phase arm arranged at the upper end of the column and the liquid phase arm arranged below the gas phase arm are automatically moved to the gas phase / liquid phase pipeline interface in the LNG tank truck operation box by using the internal servo motor component system respectively; After the loading arm is docked with the tank truck operation box, the valve body power device is controlled to start, and the valve body power device is used to provide power for the opening and closing actions of the valve bodies in the gas phase arm and the liquid phase arm; The control device sequentially controls and completes the loading arm leak detection, initial nitrogen replacement, valve opening precooling, loading valve switching and secondary nitrogen replacement operations.

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