LNG refueling station loss testing platform
By designing liquid phase, venting, and gas phase pipelines at LNG refueling stations and combining them with cryogenic flow meters, full-process monitoring of LNG and BOG is achieved, solving the problem of localized monitoring in existing technologies and providing high-precision loss statistics and safety assurance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- CHINA NAT PETROLEUM CORP SICHUAN SALES BRANCH
- Filing Date
- 2025-09-02
- Publication Date
- 2026-07-03
AI Technical Summary
Existing LNG refueling stations generate significant BOG venting and LNG loss during pumping, self-pressurized unloading, pre-cooling, and pressure equalization processes. However, current detection methods can only monitor local areas and cannot achieve real-time, full-process loss statistics for the entire station.
Design an LNG refueling station loss testing platform. Through liquid phase pipelines, venting pipelines, and gas phase pipelines, combined with a cryogenic fluid flow standard device and a cryogenic mass flow meter, it can achieve real-time accurate measurement of the flow rate, temperature, and density of LNG and BOG, and transmit the data wirelessly, forming a complete loop structure to monitor the loss throughout the entire process.
It enables integrated monitoring of all aspects of LNG refueling stations, provides high-precision loss statistics, ensures the normal operation of medium transmission, reduces the difficulty of equipment modification, and avoids safety accidents.
Smart Images
Figure CN224456238U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to an LNG refueling station loss testing platform. Background Technology
[0002] Currently, LNG refueling stations generate significant BOG (boiling gas) emissions and LNG losses at various stages, including pumping, self-pressurized unloading, precooling, and pressure equalization. However, existing detection methods often only provide localized monitoring of single stages and cannot achieve real-time, end-to-end loss statistics for the entire station. There is a lack of an integrated testing platform capable of accurately measuring and wirelessly transmitting parameters such as LNG and BOG flow rate, temperature, density, and cumulative amount. Utility Model Content
[0003] The purpose of this invention is to overcome the shortcomings of existing technologies and provide an LNG refueling station loss testing platform. This platform can simultaneously detect the real-time flow rate, temperature, and density of LNG and BOG at each stage, statistically summarize BOG emissions and LNG losses at each stage, and provide data support for refueling station operation optimization and safety management.
[0004] To achieve the above objectives, the present invention adopts the following technical solution:
[0005] An LNG refueling station loss testing platform, the testing platform including a storage tank, the storage tank being connected to a liquid phase pipeline, a venting pipeline and a gas phase pipeline respectively;
[0006] The storage tank is connected to one end of a No. 1 cryogenic fluid flow standard device via both the venting pipeline and the gas phase pipeline. The storage tank is connected to one end of both a No. 2 and a No. 3 cryogenic fluid flow standard device via the liquid phase pipeline. The other ends of the No. 1, No. 2, and No. 3 cryogenic fluid flow standard devices are respectively connected to different interfaces of the tank truck. The storage tank is connected to one end of a cryogenic mass flow meter via both the venting pipeline and the gas phase pipeline. The other end of the cryogenic mass flow meter is connected to the venting pipeline.
[0007] As a preferred embodiment, the liquid phase pipeline is connected to a submersible pump, and the submersible pump is connected to the storage tank to form a loop. The pipeline connecting the storage tank and the submersible pump is connected to several LNG refueling machines. The pipeline connecting the storage tank and the submersible pump is connected to a booster. The No. 2 cryogenic fluid flow standard device is connected to the liquid phase pipeline through the pipeline connecting the storage tank and the booster. The No. 3 cryogenic fluid flow standard device is connected to the liquid phase pipeline through the submersible pump.
[0008] As a preferred embodiment, the gas phase pipeline is connected to several of the LNG refueling machines and the booster, and the No. 1 cryogenic fluid flow standard device is connected to the gas phase pipeline through a pipeline that connects the gas phase pipeline to the booster.
[0009] As a preferred embodiment, the venting pipeline includes two branches;
[0010] One of the branch lines, the venting pipeline is connected to several of the LNG refueling machines, and the venting pipeline is also connected to several pipelines of the liquid phase pipeline. This part of the liquid phase pipeline includes a pipeline connecting the submersible pump to the storage tank, a pipeline connecting the storage tank to the LNG refueling machine, and a pipeline connecting the No. 2 cryogenic fluid flow standard device to the storage tank; the venting pipeline is connected to the pipeline connecting the No. 1 cryogenic fluid flow standard device to the gas phase pipeline.
[0011] Another branch line, the venting pipe is connected to an EGA heater, the EGA heater is connected to one end of the cryogenic mass flow meter, and the other end of the cryogenic mass flow meter is connected to the venting pipe.
[0012] In a further preferred embodiment, the venting pipeline connected to the EGA heater is sequentially connected to a safety valve and the gas phase pipeline, thereby connecting to the storage tank.
[0013] More preferably, the submersible pump is connected to the venting pipeline, and forms a loop with a portion of the venting pipeline and a portion of the liquid phase pipeline.
[0014] In a further preferred embodiment, the venting pipeline is connected twice to the pipeline that connects to the liquid phase pipeline of the No. 2 cryogenic fluid flow standard device, thereby forming a loop.
[0015] As a preferred embodiment, the No. 1, No. 2, and No. 3 cryogenic fluid flow standard devices and the cryogenic mass flow meter are all connected to each pipeline via DN50 quick-connect interfaces and hoses.
[0016] Beneficial effects:
[0017] I. Integrated monitoring of the entire process: By setting up three pipelines (liquid phase pipeline, venting pipeline, and gas phase pipeline) and cooperating with multiple sets of cryogenic fluid flow standard devices and cryogenic mass flow meters, the loss monitoring of the entire process of LNG refueling station, including precooling, pressure equalization, self-pressurization, unloading, and venting, is realized, which solves the problem that existing technologies can only monitor local areas.
[0018] II. High-precision measurement guarantee: The No. 1, No. 2, and No. 3 cryogenic fluid flow standard devices and cryogenic mass flow meters are used to accurately measure parameters such as flow rate, temperature, and density of LNG and BOG. Moreover, the mass flow meters have high accuracy, providing a precise data foundation for loss statistics.
[0019] Third, the structural design is reasonable: the connection between each pipeline and its coordination with the equipment form a complete loop, such as the submersible pump and the storage tank forming a loop, the venting pipeline and related pipelines forming a loop, which not only ensures the normal transmission of the medium, but also facilitates the accurate detection of losses in each link. Attached Figure Description
[0020] Figure 1 This is a process flow diagram of the LNG refueling station loss testing platform.
[0021] Figure 2 This is a simplified structural diagram of the LNG refueling station loss testing platform.
[0022] Figure 3 This is a pipeline connection diagram of the liquid phase pipeline of the LNG refueling station loss testing platform.
[0023] Figure 4 This is a pipeline connection diagram of the gas phase pipeline of the LNG refueling station loss testing platform.
[0024] Figure 5 This is a pipeline connection diagram of the venting pipeline of the LNG refueling station loss testing platform.
[0025] Figure 6 This is a flowchart of the self-pressurization unloading loss test process for the LNG refueling station loss test platform.
[0026] In the diagram: No. 1-1 cryogenic fluid flow rate standard device, No. 2-2 cryogenic fluid flow rate standard device, and No. 3-1 cryogenic fluid flow rate standard device. Detailed Implementation
[0027] The present invention will now be described in detail with reference to the accompanying drawings.
[0028] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.
[0029] Example:
[0030] like Figures 1 to 6As shown, the LNG refueling station loss testing platform includes a storage tank. The storage tank serves as the core of LNG storage, providing a stable medium source for self-service unloading tests and acting as a benchmark container for loss comparison. The storage tank is connected to liquid phase pipelines, venting pipelines, and gas phase pipelines, which together form a medium transmission network. These pipelines respectively undertake LNG transportation, BOG transportation, and safe venting tasks, ensuring the normal operation of medium flow and loss monitoring at each stage of self-service unloading (pre-cooling, pressure equalization, etc.).
[0031] The storage tank is connected to one end of a No. 1 cryogenic fluid flow standard device via both the venting pipeline and the gas phase pipeline. The No. 1 cryogenic fluid flow standard device focuses on the gas phase pipeline and the venting branch, accurately measuring the BOG flow rate during the self-unloading pressure equalization, pressurization, and venting stages, serving as the core of gas phase loss monitoring. The storage tank is also connected to one end of two cryogenic fluid flow standard devices via the liquid phase pipeline. The No. 2 cryogenic fluid flow standard device monitors the flow rate of the liquid phase pipeline-pressurizer branch, capturing the liquid phase flow rate and gas phase loss (such as BOG generated by pressurization heat loss) during the self-unloading pressurization stage. The No. 3 cryogenic fluid... The flow standard device measures the flow rate of the liquid phase pipeline-submersible pump branch, covering liquid phase losses (pumping leakage, circulation heat loss) in the self-service unloading (bottom inlet) and circulation links. The other ends of the No. 1, No. 2, and No. 3 cryogenic fluid flow standard devices are respectively connected to different interfaces of the tank truck. The storage tank is connected to one end of the cryogenic mass flow meter through the vent pipeline and the gas phase pipeline. The cryogenic mass flow meter is connected in series at the end of the vent pipeline to accurately measure the final vented BOG mass. It is the final checkpoint for the overall station vent loss statistics. The U-shaped bend enhances the measurement accuracy and is suitable for low temperature and high pressure environments. The other end of the cryogenic mass flow meter is connected to the vent pipeline.
[0032] The liquid phase pipeline is connected to a submersible pump, which is connected to the storage tank and forms a loop. The submersible pump provides power to the liquid phase pipeline, driving LNG to circulate in the "storage tank → dispenser → storage tank" loop, simulating actual pumping conditions, and is used in conjunction with Unit 3 to test pumping losses. The pipeline connecting the storage tank and the submersible pump is connected to several LNG dispensers. The LNG dispensers can simulate actual refueling scenarios and test the flow accuracy and losses (such as refueling leakage, BOG generation) in the refueling process. The venting branch is connected to simultaneously monitor refueling venting losses. The pipeline connecting the storage tank and the submersible pump is connected to a booster, which can maintain stable tank pressure and ensure smooth unloading and refueling. The pressure-flow matching and gas phase losses in the boosting process are tested using Unit 2. The No. 2 cryogenic fluid flow standard device is connected to the liquid phase pipeline through the pipeline connecting the storage tank and the booster, and the No. 3 cryogenic fluid flow standard device is connected to the liquid phase pipeline through the submersible pump.
[0033] The gas phase pipeline is connected to several of the LNG refueling machines and the booster, and the No. 1 cryogenic fluid flow standard device is connected to the gas phase pipeline through a pipeline that connects the gas phase pipeline to the booster.
[0034] The venting pipeline includes two branches;
[0035] One of the branch lines, the venting pipeline is connected to several of the LNG refueling machines, and the venting pipeline is also connected to several pipelines of the liquid phase pipeline. This part of the liquid phase pipeline includes a pipeline connecting the submersible pump to the storage tank, a pipeline connecting the storage tank to the LNG refueling machine, and a pipeline connecting the No. 2 cryogenic fluid flow standard device to the storage tank; the venting pipeline is connected to the pipeline connecting the No. 1 cryogenic fluid flow standard device to the gas phase pipeline.
[0036] In the other branch, the venting pipe is connected to an EGA heater. The core function of the EGA heater is to heat the vented low-temperature BOG (boiling point approximately -162°C) to near room temperature. This prevents the low-temperature BOG from directly entering the low-temperature mass flow meter and subsequent venting pipe, which could lead to material embrittlement and seal failure due to low temperatures. This ensures the safe and stable operation of the metering equipment and pipeline, while also ensuring that the low-temperature mass flow meter operates at a suitable temperature, thus improving metering accuracy. The EGA heater is connected to one end of the low-temperature mass flow meter, and the other end of the low-temperature mass flow meter is connected to the venting pipe.
[0037] The EGA heater is connected to the venting pipeline, which is sequentially connected to the safety valve and the gas phase pipeline, thus connecting to the storage tank. The safety valve is the core component of overpressure protection. When the pressure in the storage tank, gas phase pipeline, or venting pipeline exceeds the set value (such as due to excessive BOG or a sudden pressure rise caused by an external heat source), the safety valve automatically opens, introducing the high-pressure medium (BOG or LNG vapor) into the EGA heater through the venting pipeline. After heating, it is measured by a cryogenic mass flow meter and finally safely discharged through the venting pipeline. This connection method forms a closed loop of "abnormal pressure → safety valve action → medium venting → heating and measurement → safe discharge," ensuring that the medium under overpressure can be vented in an orderly manner along a preset path, avoiding safety accidents such as pipeline rupture and equipment damage caused by excessive pressure.
[0038] The submersible pump is connected to the venting pipeline and forms a loop with a portion of the venting pipeline and a portion of the liquid phase pipeline. By forming a loop with the venting pipeline and a portion of the liquid phase pipeline, the "LNG circulation condition" in the non-unloading state of the gas station can be simulated (such as the submersible pump continuously pushing LNG to circulate between the storage tank, liquid phase pipeline, and venting pipeline). This ensures that the test platform can not only monitor the flow loss during unloading, but also capture the loss during the circulation process (such as BOG venting caused by pipeline friction and temperature fluctuations, or trace leakage during the operation of the submersible pump).
[0039] The venting pipeline is connected twice to the pipeline that connects to the liquid phase pipeline of the No. 2 cryogenic fluid flow standard device, thus forming a loop; it mainly monitors the flow rate during the pressurization process (such as the LNG flow when the pressurizer is working). The "double connection" of the venting pipeline to form a loop allows BOG or excess LNG generated during the pressurization process to flow through the measurement area twice through the venting pipeline. This facilitates cross-verification of flow data by the monitoring equipment of the No. 2 device and the venting pipeline (such as the No. 1 device), and accurately measures the venting losses during the pressurization process (such as BOG venting caused by pressurization overheating).
[0040] The No. 1, No. 2, and No. 3 cryogenic fluid flow standard devices and the cryogenic mass flow meter are all connected to the pipelines via DN50 quick-connect interfaces and hoses. The DN50 quick-connect interfaces and hoses enable quick connection between the equipment and the pipelines, reduce the difficulty of on-site modification, ensure connection sealing and pressure resistance, and are suitable for rapid deployment of self-service unloading tests.
[0041] like Figure 6 The self-pressurized unloading fluid loss test process is shown below:
[0042] (I) Functions and roles of components in each stage
[0043] Test preparation:
[0044] Function of the component: To check the status of testing instruments (flow devices, mass flow meters) and material valves (tank trucks, storage tank valves), and to record the initial liquid level and pressure of the tank trucks and storage tanks, so as to lay the foundation for data comparison throughout the entire process.
[0045] Implementation: Confirm that the submersible pump and booster are in standby mode, zero and initialize the flow standard device and mass flow meter, and enter the initial data (liquid level, pressure) using an explosion-proof computer.
[0046] purge and precooling:
[0047] Functions of the components: The tank truck is continuously purged multiple times to remove impurities from the pipeline; the No. 1 cryogenic fluid flow standard device monitors the gas phase flow during the pre-cooling stage and captures the pre-cooling venting loss.
[0048] Implementation: Open the vent valve and tank truck gas phase pipe, purge the process pipeline according to the process flow, and then close the valve; simultaneously start Unit 1, and record the gas phase data (flow rate, mass) of the tank and flow meter as a basis for pre-cooling loss.
[0049] Flattening:
[0050] Functions of the components: The submersible pump and booster work together to maintain pressure; Units 3 (liquid phase) and 1 (gas phase) monitor and balance the flow rate; and the venting branch ensures the release and measurement of abnormal pressure.
[0051] Implementation: Slowly open the liquid phase connection valve between the storage tank and the tank truck, and slightly open the gas phase test valve to balance the pressure; when the tank truck pressure is ≤0.7MPa, close the valves and record the liquid / gas phase data (pressure balancing amount) using devices No. 3 and No. 1; if the pressure exceeds the limit, close the emergency shut-off valve 1, fine-tune the liquid phase valve and gas phase test valve of the tank truck, and repeat the pressure balancing operation until the pressure reaches the standard.
[0052] Boost:
[0053] Functions of the components: When the booster is working, Unit 2 monitors the liquid phase booster flow rate, and Unit 1 monitors the booster BOG generation; the safety valve and mass flow meter in the venting branch are on standby to capture overpressure venting losses.
[0054] Implementation: Sequentially open the tank truck gas phase valve, tank gas phase test connection valve, and tank truck liquid phase valve to bring the tank truck pressure to the set value; record the pressurized gas phase data of devices 2 and 1, and calculate the loss (pressurized gas phase loss = pressurizer gas phase volume - storage tank gas phase volume); if the pressure difference between the tank truck and the storage tank is ≥0.2MPa, proceed with unloading; otherwise, repeat the pressurization operation.
[0055] Unloading (top inlet / bottom inlet):
[0056] Functions of the components: The submersible pump drives the LNG to be unloaded into the storage tank; Units 3 (lower inlet) and 2 (upper inlet) measure the flow rate of different paths; and the gas phase pipeline and venting pipeline simultaneously monitor the BOG release during unloading.
[0057] Implementation: When the liquid is fed upwards, open the liquid feed overflow valve and close the bypass valve to maintain pressurization. Units 3 and 2 record the liquid feed data and the unloading gas phase volume (unloading gas phase loss = pressurizer gas phase volume - storage tank gas phase volume); when the liquid is fed downwards, switch the valve when the LNG balance is 25%, and unit 3 records the liquid feed data.
[0058] Tanker flat pressure:
[0059] Function of the component: The gas phase valve of the tank truck connects to the gas phase space of the storage tank to balance the pressure, and the gas phase flow meter records the balanced gas phase data to improve the statistics of unloading losses.
[0060] Implementation: Gas phase valve 1 of the slotting vehicle utilizes the gas phase space of the storage tank to balance the pressure. Device 1 records the gas phase flow rate and mass under pressure (adjusting the pressure balance).
[0061] (II) Data Integration and Analysis Phase
[0062] Data Acquisition: During the test, each device transmits data such as flow rate, pressure, and temperature to the explosion-proof computer in real time via wireless module (or direct connection). Customized software stores the data according to the process (data such as pre-cooling and pressure equalization are archived independently).
[0063] Loss Calculation: The explosion-proof computer and customized software receive and store data, integrate and analyze it according to the algorithm (e.g., total unloading loss = pre-cooling loss + pressure equalization loss + pressurization loss + unloading liquid loss), and output loss statistics results.
[0064] Analysis and Application: By comparing historical data and industry standards, we can analyze the sources of losses in the unloading process (such as excessive losses in the pressurization process) and provide suggestions for process adjustment (optimizing pressurization parameters), thus providing a basis for the optimization of gas station operations and safety management.
[0065] Through the above implementation methods, this testing platform can accurately and comprehensively adapt to the self-service unloading process of LNG refueling stations, realize full-process loss monitoring, and enable the components to work together at different stages, providing an effective technical solution for the testing and optimization of similar facilities in the industry.
[0066] This invention is not limited to the specific embodiments described above. This invention extends to any new feature or combination disclosed in this specification, as well as any new method or process step or combination disclosed herein.
Claims
1. An LNG filling station loss testing platform, characterized in that: The test platform includes a storage tank, which is connected to a liquid phase pipeline, a venting pipeline, and a gas phase pipeline, respectively. The storage tank is connected to one end of a No. 1 cryogenic fluid flow standard device via both the venting pipeline and the gas phase pipeline. The storage tank is connected to one end of both a No. 2 and a No. 3 cryogenic fluid flow standard device via the liquid phase pipeline. The other ends of the No. 1, No. 2, and No. 3 cryogenic fluid flow standard devices are respectively connected to different interfaces of the tank truck. The storage tank is connected to one end of a cryogenic mass flow meter via both the venting pipeline and the gas phase pipeline. The other end of the cryogenic mass flow meter is connected to the venting pipeline.
2. The LNG fueling station loss test platform of claim 1, wherein: The liquid phase pipeline is connected to a submersible pump, and the submersible pump is connected to the storage tank to form a loop. The pipeline connecting the storage tank and the submersible pump is connected to several LNG refueling machines. The pipeline connecting the storage tank and the submersible pump is connected to a booster. The No. 2 cryogenic fluid flow standard device is connected to the liquid phase pipeline through the pipeline connecting the storage tank and the booster. The No. 3 cryogenic fluid flow standard device is connected to the liquid phase pipeline through the submersible pump.
3. The LNG fueling station loss test platform of claim 2, wherein: The gas phase pipeline is connected to several of the LNG refueling machines and the booster, and the No. 1 cryogenic fluid flow standard device is connected to the gas phase pipeline through a pipeline that connects the gas phase pipeline to the booster.
4. The LNG fueling station loss test platform of claim 2, wherein: The venting pipeline includes two branches; One of the branch lines, the venting pipeline is connected to several of the LNG refueling machines, and the venting pipeline is also connected to several pipelines of the liquid phase pipeline. This part of the liquid phase pipeline includes a pipeline connecting the submersible pump to the storage tank, a pipeline connecting the storage tank to the LNG refueling machine, and a pipeline connecting the No. 2 cryogenic fluid flow standard device to the storage tank; the venting pipeline is connected to the pipeline connecting the No. 1 cryogenic fluid flow standard device to the gas phase pipeline. Another branch line, the venting pipe is connected to an EGA heater, the EGA heater is connected to one end of the cryogenic mass flow meter, and the other end of the cryogenic mass flow meter is connected to the venting pipe.
5. The LNG fueling station loss test platform of claim 4, wherein: The EGA heater is connected to the venting pipeline, which is sequentially connected to the safety valve and the gas phase pipeline, thereby connecting to the storage tank.
6. The LNG fueling station loss test platform of claim 2, wherein: The submersible pump is connected to the venting pipeline and forms a loop with a portion of the venting pipeline and a portion of the liquid phase pipeline.
7. The LNG fueling station loss test platform of claim 1, wherein: The venting pipeline is connected twice to the pipeline that connects to the liquid phase pipeline of the No. 2 cryogenic fluid flow standard device, thus forming a loop.
8. The LNG fueling station loss test platform of claim 1, wherein: The No. 1, No. 2, and No. 3 cryogenic fluid flow standard devices and the cryogenic mass flow meter are all connected to the respective pipelines via DN50 quick-connect interfaces and hoses.