Control device for one-key unloading of LNG tank car

Abstract

The utility model relates to the field of petrochemical equipment, and provides a control device for one-key unloading of an LNG (Liquefied Natural Gas) tank car, which comprises an unloading controller as well as a pressurization line pressure transmitter, a pressurization line stop valve, a pressurization line regulating valve, a gas phase line stop valve, a gas phase line pressure transmitter, a gas phase line temperature transmitter and a gas phase line bypass regulating valve which are electrically connected with the unloading controller, the device comprises a liquid phase line flow meter, a liquid phase line stop valve, a liquid phase line pressure transmitter, a liquid phase line temperature transmitter and a grounding assembly. The unloading controller outputs a valve control signal according to the requirement of an unloading standard process by obtaining data of an instrument and a transmitter and the state of the valve, one-key automatic unloading is achieved, the mode that an existing unloading process adopts full-manual operation is improved, manpower and time are greatly saved, and unloading efficiency and safety are improved.

Description

Technical Field

[0001] This utility model belongs to the field of petrochemical equipment, specifically relating to a control device for one-click unloading of LNG tank trucks. Background Technology

[0002] LNG unloading involves using an LNG vaporizer or BOG compressor to obtain high-pressure vaporized gas, which is then injected into the tank truck through a gas-connection pipe, thus forcing the LNG liquid out of the tank truck. The core operational process for LNG tank truck unloading generally involves: connecting and purging the tank truck's pressurization and unloading pipelines; pressurizing the tank truck using a pressurizer, with the operator monitoring the pressure changes inside the tank truck in real time using instruments; and opening the tank truck's outlet and storage tank's inlet valves when the pressure reaches a certain level, allowing LNG to enter the storage tank. During unloading, operators should continuously monitor pressure changes in both the storage tank and the tank truck, manually operating the corresponding valves to replenish pressure in the tank truck as needed. After LNG unloading is complete, the storage tank's main inlet valve is closed, and the gas-liquid balance valve is opened to release the pressure from the unloading pipeline to the BOG system through the vapor phase line. When no more gas can be unloaded from the tank truck, the LNG tank truck's inlet valve is closed.

[0003] Currently, during the LNG tanker unloading process, all valve operations and the monitoring of parameters such as pressure and temperature are performed manually by professional operators, consuming a significant amount of manpower and time, resulting in low unloading efficiency. Furthermore, as LNG is a hazardous chemical, the efficiency is even lower for general personnel or novices who lack professional operating experience, and serious production accidents may occur during unloading due to improper operation caused by human factors. Utility Model Content

[0004] The technical problem to be solved by this utility model is how to make up for the shortcomings of the above-mentioned LNG tanker unloading operation process and realize one-click automatic unloading of LNG tankers.

[0005] This utility model solves the above-mentioned technical problems through the following technical solution:

[0006] This utility model provides a control device for one-click unloading of LNG tank trucks, including:

[0007] The unloading controller and its electrically connected components include a booster line pressure transmitter, a booster line shut-off valve, a booster line regulating valve, a vapor line shut-off valve, a vapor line pressure transmitter, a vapor line temperature transmitter, a vapor line bypass regulating valve, a liquid line flow meter, a liquid line shut-off valve, a liquid line pressure transmitter, a liquid line temperature transmitter, and a grounding assembly.

[0008] Furthermore, the unloading controller uses a PLC as its control core, is equipped with a color LCD display and an explosion-proof keyboard, and is connected to the valves, measuring instruments, transmitters and grounding components in the control device through shielded signal lines.

[0009] Furthermore, both the booster line pressure transmitter and the vapor phase line pressure transmitter use gauge pressure sensors and are equipped with LCD gauges.

[0010] Furthermore, the booster line shut-off valve, gas phase line shut-off valve, and liquid phase line shut-off valve all adopt pneumatic switch ball valves and single-acting pneumatic piston actuators, and control the opening and closing of the valves by controlling the on / off of the instrument air through a solenoid valve.

[0011] Furthermore, both the booster line regulating valve and the gas phase line bypass regulating valve adopt Globe-type pneumatic regulating valves with single-acting diaphragm actuators, and the valve opening degree is controlled by an electric positioner within the range of 0% to 100%.

[0012] Furthermore, both the vapor phase temperature transmitter and the liquid phase temperature transmitter use resistance temperature sensors and are equipped with LCD displays.

[0013] Furthermore, the liquid flow meter is a Coriolis mass flow meter that directly measures the mass flow signal and sends it to the unloading controller in the form of a pulse signal.

[0014] Furthermore, the grounding assembly includes a grounding clamp, a grounding wire, and an electrostatic grounding controller, which is used to guide the static electricity generated by the friction between the flowing LNG and the pipeline during the unloading process into the grounding grid. At the same time, the electrostatic grounding controller determines whether the tank truck is properly grounded to avoid electrostatic explosion accidents.

[0015] The advantages of this utility model are:

[0016] (1) This utility model adopts the electrical connection between the unloading controller and valves, instruments, and transmitters. By acquiring data from the instruments and transmitters and the valve status, it outputs control valve signals according to the requirements of the unloading procedure, realizing one-button automatic unloading, which greatly saves manpower and time. Moreover, the unloading pressure and speed can be automatically controlled, and the functions of automatic interlocking valve closure alarm when the pressure is too high are improved, thus improving the safety of the unloading process.

[0017] (2) Compared with the traditional manual unloading process, this utility model only requires the addition of a controller on site and modification of the valves, instruments and transmitters corresponding to the unloading pipeline. The engineering construction is simple and easy to promote and use. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the control device for one-click unloading of an LNG tanker truck according to Embodiment 1 of this utility model.

[0019] Among them, 1-unloading controller, 2-boost line pressure transmitter, 3-boost line shut-off valve, 4-boost line regulating valve, 5-vapor line shut-off valve, 6-vapor line pressure transmitter, 7-vapor line temperature transmitter, 8-vapor line bypass regulating valve, 9-liquid line flow meter, 10-liquid line shut-off valve, 11-liquid line pressure transmitter, 12-liquid line temperature transmitter, 13-vapor line loading arm, 14-liquid line loading arm, 15-grounding assembly. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below in conjunction with the embodiments of this utility model. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0021] The technical solution of this utility model will be further described below with reference to the accompanying drawings and specific embodiments:

[0022] Example 1

[0023] This utility model embodiment provides a control device for one-click unloading of LNG tank trucks, such as... Figure 1 As shown, it includes:

[0024] The unloading controller 1 and its electrically connected components include: a booster line pressure transmitter 2, a booster line shut-off valve 3, a booster line regulating valve 4, a vapor line shut-off valve 5, a vapor line pressure transmitter 6, a vapor line temperature transmitter 7, a vapor line bypass regulating valve 8, a liquid line flow meter 9, a liquid line shut-off valve 10, a liquid line pressure transmitter 11, a liquid line temperature transmitter 12, and a grounding assembly 15. It also includes vapor line loading arms 13 and liquid line loading arms 14 that connect to the tank truck.

[0025] Starting from the main pressurization pipe of the dump truck, the pressurization line pressure transmitter 2, pressurization line shut-off valve 3, pressurization line regulating valve 4, vapor line shut-off valve 5, vapor line pressure transmitter 6, vapor line temperature transmitter 7, and vapor line loading arm 13 are connected in series.

[0026] The input end of the gas phase line shut-off valve 5 and the gas phase line bypass regulating valve 8 connected in parallel is located between the booster line regulating valve 4 and the gas phase line pressure transmitter 6, and the output end goes to the BOG equalization main pipe.

[0027] Starting from the liquid phase main unloading pipe of the tank truck, the liquid phase flow meter 9, liquid phase shut-off valve 10, liquid phase pressure transmitter 11, liquid phase temperature transmitter 12, and liquid phase loading arm 14 are connected in series.

[0028] The unloading controller 1 is designed for use in hazardous explosive environments. It employs a PLC as its control core and is equipped with a color LCD display and an explosion-proof keyboard. It is used for the automatic control of the entire unloading process and is the core component for achieving one-button automatic unloading. The unloading controller connects to the control valves, measuring instruments, and transmitters in the unloading control device via shielded control cables to acquire instrument readings, valve status, and output valve control signals.

[0029] The booster line pressure transmitter 2 uses a gauge pressure sensor and is equipped with an LCD meter for on-site display and output of the booster line pressure signal.

[0030] The booster line shut-off valve 3 is a pneumatic ball valve with a single-acting pneumatic piston actuator. It controls the opening and closing of the valve by controlling the flow of instrument air through a solenoid valve, and is used to control the flow of gas in the booster line.

[0031] The booster line regulating valve 4 is a Globe-type pneumatic regulating valve with a single-acting diaphragm actuator. The valve opening is controlled by an electric positioner and can operate at any opening within the range of 0% to 100%, used for controlling the gas flow rate of the booster line.

[0032] The gas phase line shut-off valve 5 adopts a pneumatic switch ball valve and a single-acting pneumatic piston actuator. It controls the opening and closing of the valve by controlling the instrument air flow through a solenoid valve, and is used to control the gas flow of the gas phase line.

[0033] The vapor pressure transmitter 6 uses a gauge pressure sensor and is equipped with an LCD meter for on-site display and output of vapor pressure signals.

[0034] The vapor phase temperature transmitter 7 uses a resistance temperature sensor and is equipped with an LCD meter for on-site display and output of vapor phase temperature signals.

[0035] The vapor phase line bypass regulating valve 8 adopts a Globe-type pneumatic regulating valve with a single-acting diaphragm actuator. The opening degree of the regulating valve is controlled by an electric positioner. It can operate at any opening degree within the range of 0% to 100%. It is used to control the gas flow rate of the vapor phase line during pressure equalization and reduce noise during pressure equalization.

[0036] The liquid flow meter 9 is a Coriolis mass flow meter that can directly measure mass flow signals. It is not affected by temperature and density and can send the mass flow signals to the unloading controller in the form of pulse signals to measure the total unloading volume.

[0037] The liquid line shut-off valve 10 adopts a pneumatic switch ball valve and a single-acting pneumatic piston actuator. It controls the opening and closing of the valve by controlling the instrument air flow through a solenoid valve, and is used to control the liquid flow of the liquid line.

[0038] The liquid line pressure transmitter 11 uses a gauge pressure sensor and is equipped with an LCD meter for on-site display and output of the liquid line pressure signal.

[0039] The liquidus temperature transmitter 12 uses a resistance temperature sensor and is equipped with an LCD display for on-site display and output of the liquidus temperature signal.

[0040] The vapor line loading arm 13 connects the fluid transport pipelines to each other through 5 rotary joints, enabling the pipelines to move and connect arbitrarily in three-dimensional space, while ensuring that no medium leaks into the environment during the fluid transport process. It is used to transport pressurized gas into the tank truck during the unloading process, and to discharge the high-pressure gas in the tank truck after unloading is completed.

[0041] The liquid line loading arm 14 connects the fluid transport pipelines to each other through 5 rotary joints, enabling the pipelines to move and connect arbitrarily in three-dimensional space, while ensuring that no medium leaks into the environment during the fluid transport process. It is used to transport LNG from tank trucks to storage tanks.

[0042] The grounding assembly 15 includes a grounding clamp, a grounding wire, and an electrostatic grounding controller. It is used to conduct static electricity generated by the friction between the flowing LNG and the pipeline during unloading into the grounding grid. Simultaneously, the electrostatic grounding controller determines whether the tank truck is properly grounded, preventing electrostatic explosion accidents.

[0043] In this embodiment, the specific operation mode of the above-mentioned LNG tanker one-click unloading system is as follows:

[0044] Once the tanker arrives at the station and is parked at the designated unloading position, the tanker is connected to the grounding component 15. Static electricity is eliminated through the grounding busbar, and the grounding component transmits the grounding status of the tanker to the unloading controller.

[0045] Before unloading, the vapor line loading arm 13 and the liquid line loading arm 14 must be connected to the vapor and liquid phase pipes of the LNG tanker respectively, and the loading arm valves must be purged and opened. Then, one-button unloading can be started through the unloading controller. The unloading controller can divide the entire unloading process into three stages: pressurization, unloading, and pressure equalization, based on the vapor line pressure.

[0046] When unloading begins, the unloading controller first determines whether the pressure of the booster line meets the unloading conditions based on the booster line pressure transmitter 2. If it does, the booster line shut-off valve 3 is opened to pressurize the tank truck. After the gas phase line pressure transmitter 6 detects that the pressure meets the unloading conditions, the unloading controller controls the liquid phase line shut-off valve 10 to be opened, and the unloading stage begins.

[0047] During the unloading process, on the one hand, the liquid phase flow meter 9 monitors the flow data in real time, and on the other hand, the liquid phase pressure transmitter 11 and the liquid phase temperature transmitter 12 monitor the liquid phase pressure and temperature status in real time. When the temperature detected by the liquid phase temperature transmitter 12 rises to the preset value specified in the unloading operation procedure, and the pressure detected by the liquid phase pressure transmitter 11 drops to the preset value specified in the unloading operation procedure, it can be determined that the tank truck unloading has been completed and the pressure leveling stage has begun.

[0048] The unloading controller closes the booster line shut-off valve 3 and the liquid line shut-off valve 10, then opens the vapor line bypass regulating valve 8 to begin pressure stabilization. When the vapor line pressure transmitter 6 detects that the pressure has dropped to the preset value specified in the unloading operation procedure, it opens the vapor line shut-off valve 5 to accelerate pressure stabilization. When the vapor line pressure transmitter 6 detects that the pressure has dropped to a safe value, it closes the vapor line shut-off valve 5 and the vapor line bypass regulating valve 8, completing the pressure stabilization process. Thus, the unloading controller, by receiving signals from the transmitters on the pipeline, automatically controls the corresponding shut-off and regulating valves, concluding the one-button fully automatic control process during unloading.

[0049] The above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A control device for one-click unloading of LNG tank trucks, characterized in that, include: Unloading controller and its electrically connected components, including booster line pressure transmitter, booster line shut-off valve, booster line regulating valve, vapor line shut-off valve, vapor line pressure transmitter, vapor line temperature transmitter, vapor line bypass regulating valve, liquid line flow meter, liquid line shut-off valve, liquid line pressure transmitter, liquid line temperature transmitter, and grounding assembly. Starting from the main pressurization pipe of the dump truck, the pressurization line pressure transmitter, pressurization line shut-off valve, pressurization line regulating valve, vapor line shut-off valve, vapor line pressure transmitter, vapor line temperature transmitter, and vapor line loading arm are connected in series. The input end of the gas phase line shut-off valve and the gas phase line bypass regulating valve connected in parallel is located between the booster line regulating valve and the gas phase line pressure transmitter, and the output end goes to the BOG equalization main pipe. Starting from the liquid phase main unloading pipe of the tank truck, the liquid phase flow meter, liquid phase shut-off valve, liquid phase pressure transmitter, liquid phase temperature transmitter, and liquid phase loading arm are connected in series in sequence.

2. The control device for one-click unloading of LNG tank trucks according to claim 1, characterized in that, The unloading controller includes a PLC, a color LCD display, and an explosion-proof keyboard. The color LCD display and the explosion-proof keyboard are connected to the PLC. The PLC is connected to the valves, measuring instruments, transmitters, and grounding components in the control device via shielded signal lines.

3. The control device for one-click unloading of LNG tank trucks according to claim 1, characterized in that, Both the booster line pressure transmitter and the vapor line pressure transmitter use gauge pressure sensors and are equipped with LCD gauges.

4. The control device for one-click unloading of LNG tank trucks according to claim 1, characterized in that, The booster line shut-off valve, gas phase line shut-off valve, and liquid phase line shut-off valve all adopt pneumatic switch ball valves and single-acting pneumatic piston actuators.

5. The control device for one-click unloading of LNG tank trucks according to claim 1, characterized in that, Both the booster line regulating valve and the vapor phase line bypass regulating valve are Globe-type pneumatic regulating valves with single-acting diaphragm actuators.

6. The control device for one-click unloading of LNG tank trucks according to claim 1, characterized in that, Both the vapor phase temperature transmitter and the liquid phase temperature transmitter use resistance temperature sensors and are equipped with LCD displays.

7. The control device for one-click unloading of LNG tank trucks according to claim 1, characterized in that, The liquid flow meter is a Coriolis mass flow meter.

8. The control device for one-click unloading of LNG tank trucks according to claim 1, characterized in that, The grounding assembly includes a grounding clamp, a grounding wire, and an electrostatic grounding controller.

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