A circulating heat exchange device for a compressed gas supply system in an LNG refueling station

Abstract

This utility model belongs to the technical field of gas station technology, and specifically relates to a circulating heat exchange device for an LNG refueling station compressed gas supply system. The technical solution is as follows: A circulating heat exchange device for an LNG refueling station compressed gas supply system includes a compressed air system, an LNG pump skid, and a liquid dispenser. An instrument air duct connects the compressed air system, the LNG pump skid, and the liquid dispenser. It also includes a heating unit containing a liquid for heat exchange. A circulating heat exchange pipeline is installed inside the instrument air duct, and the inlet and outlet of the circulating heat exchange pipeline are both connected to the heating unit. This utility model provides a circulating heat exchange device for an LNG refueling station compressed gas supply system that can effectively prevent ice blockage.

Description

Technical Field

[0001] This utility model belongs to the field of gas station technology, and specifically relates to a circulating heat exchange device for an LNG gas station compressed gas supply system. Background Technology

[0002] Currently, there are over 6,000 LNG refueling stations in operation nationwide. The compressed air system of these stations, consisting of air compressors and dryers, provides control air to the LNG pump skids and refueling machines via instrument air ducts. Due to untimely or malfunctioning drainage, water often accumulates in the instrument air ducts, making detection and automatic drainage impossible.

[0003] Instrument air ducts are currently laid by digging trenches and burying them directly, with a burial depth of about 1 meter. In northern gas stations, due to the low winter temperatures, the ground usually freezes in November, making construction impossible. Moreover, the instrument air ducts located in the frozen soil layer are prone to ice blockage and blockage due to the presence of water inside, low gas consumption at night, or when there is no gas filling. This prevents the gas station from starting normal operation in the morning.

[0004] Gas stations have been plagued by this problem and urgently need to find a new solution, device, and process control system that can effectively prevent ice blockage from recurring. Utility Model Content

[0005] In order to solve the above-mentioned problems in the existing technology, the purpose of this utility model is to provide a circulating heat exchange device for the compressed gas supply system of LNG refueling station that can effectively prevent ice blockage.

[0006] The technical solution adopted in this utility model is as follows: A circulating heat exchange device for a compressed gas supply system in an LNG refueling station includes a compressed air system, an LNG pump skid, and a liquid dispenser. An instrument air duct connects the compressed air system, the LNG pump skid, and the liquid dispenser. The device also includes a heating unit containing a liquid for heat exchange. A circulating heat exchange pipeline is installed inside the instrument air duct, and the inlet and outlet of the circulating heat exchange pipeline are both connected to the heating unit.

[0007] The heating unit of this invention can heat the internal liquid, and the heated liquid circulates between the heating unit and the circulating heat exchange pipeline. The circulating heat exchange pipeline is located inside the instrument air duct, thereby heating the compressed air inside the instrument air duct and preventing water accumulation and ice blockage in the instrument air duct.

[0008] In a preferred embodiment of this invention, the heating unit includes a housing, in which liquid is contained. An electric heating wire is installed inside the housing, and a booster pump is mounted on the housing. The outlet of the booster pump is connected to the inlet of a circulating heat exchange pipeline. The electric heating wire heats the liquid inside the housing, and the booster pump delivers the heated liquid to the circulating heat exchange pipeline, thus achieving liquid circulation.

[0009] In a preferred embodiment of this invention, a liquid tank is connected to the housing via a pipeline, and a first valve is connected to the pipeline between the liquid tank and the housing. The liquid tank supplies liquid to the housing, and the first valve controls the flow between the liquid tank and the housing.

[0010] As a preferred embodiment of this utility model, a low-level gauge and a high-level gauge are installed inside the tank. The liquid level inside the tank needs to be maintained between the low and high levels. When the liquid level is too low, liquid is added to the tank through a liquid tank, and the liquid level does not exceed the high level when adding liquid.

[0011] As a preferred embodiment of this invention, a first temperature sensor is installed inside the chamber. The first temperature sensor can detect the temperature of the liquid inside the chamber and control the on / off state of the electric heating wire based on the liquid temperature.

[0012] As a preferred embodiment of this invention, filters are provided at both the outlet of the circulating heat exchange pipeline and the inlet of the booster pump. The filters can remove impurities from the liquid.

[0013] In a preferred embodiment of this invention, the instrument air duct is connected to several drain connectors, each connected to a shut-off valve; a liquid sensor is also connected to each drain connector. When the liquid sensor detects water accumulation in the drain connector, the shut-off valve is opened to drain the water.

[0014] As a preferred embodiment of this invention, a fluid sensor is connected to the instrument air duct. The fluid sensor can automatically detect whether the fluid inside the instrument air duct is in a flowing or stationary state.

[0015] As a preferred embodiment of this invention, a second temperature sensor is connected to the instrument air duct. The second temperature sensor can detect the temperature of the compressed air inside the instrument air duct and control whether the heating unit needs to be activated based on the collected temperature.

[0016] As a preferred embodiment of this invention, a purging pipe is connected to a section of the circulating heat exchange pipeline before it enters the instrument air duct. After the air in the instrument air duct is heated by the heating unit, the liquid in the circulating heat exchange pipeline is purged into the housing through the purging pipe to prevent the liquid in the circulating heat exchange pipeline from freezing.

[0017] The beneficial effects of this utility model are as follows: The heating unit of this invention can heat the internal liquid, and the heated liquid circulates between the heating unit and the circulating heat exchange pipeline. The circulating heat exchange pipeline is located inside the instrument air duct, thereby heating the compressed air inside the instrument air duct and preventing water accumulation and ice blockage in the instrument air duct. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2 yes Figure 1 A magnified view of a section at point A in the middle; Figure 3 This is a schematic diagram of the heating unit. Figure 4 This is a cross-sectional view of the instrument air duct; Figure 5 This is a schematic diagram of a compressed air system; Figure 6 This is a structural schematic diagram of an LNG pump skid; Figure 7 This is a schematic diagram of the liquid dispenser.

[0019] In the diagram: 1-Compressed air system; 2-LNG pump skid; 3-Liquid dispenser; 4-Instrument air duct; 5-Heating unit; 6-Circulating heat exchange pipeline; 7-PLC control system; 8-Purge pipeline; 11-Air compressor; 12-Dryer; 13-Filter device; 21-Instrument air buffer tank; 31-Cable trench; 32-LNG pipeline trench; 41-Drain connector; 42-Stop valve; 43-Liquid sensor; 44-Fluid sensor; 45-Second temperature sensor; 51-Box; 52-Electric heating wire; 53-Booster pump; 54-Filter; 55-Liquid tank; 56-First valve; 57-Low level gauge; 58-High level gauge; 59-First temperature sensor; 61-Second valve; 81-Third valve. 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 with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0021] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of the present invention can be combined with each other.

[0022] like Figures 1 to 7 As shown, the circulating heat exchange device of the LNG refueling station compressed gas supply system in this embodiment includes a compressed air system 1, an LNG pump skid 2, and a liquid dispenser 3. An instrument air duct 4 is connected between the compressed air system 1, the LNG pump skid 2, and the liquid dispenser 3. It also includes a heating unit 5, which contains a liquid for heat exchange. A circulating heat exchange pipeline 6 is installed inside the instrument air duct 4. The inlet and outlet of the circulating heat exchange pipeline 6 are both connected to the heating unit 5. The heating unit 5 is located in the non-explosion-proof area of ​​the refueling station.

[0023] The compressed air system 1 includes an air compressor 11, which is connected to a dryer 12 via a pipeline. The dryer 12 is connected to a filter device 13 via a pipeline, and the filter device 13 is connected to an instrument air duct 4 via a pipeline. The instrument air duct 4 is connected to an instrument air buffer tank 21 on the LNG pump skid 2. The LNG dispenser 3 is connected to a cable, and an LNG pipeline connects the LNG dispenser 3 to the LNG pump skid 2. The cable is installed in a cable trench 31, and the LNG pipeline is installed in an LNG pipeline trench 32.

[0024] The heating unit 5 of this invention can heat the internal liquid, and the heated liquid circulates between the circulating heat exchange pipe 6 and the heating unit 5. The circulating heat exchange pipe 6 is installed inside the instrument air duct 4, so that the circulating heat exchange pipe 6 can heat the compressed air inside the instrument air duct 4, avoiding the situation where water accumulates and freezes inside the instrument air duct 4, causing ice blockage.

[0025] Specifically, the heating unit 5 includes a housing 51, with liquid (antifreeze or water) placed inside. An electric heating wire 52 is installed inside the housing 51, and a booster pump 53 is mounted on the housing 51. The outlet of the booster pump 53 is connected to the inlet of the circulating heat exchange pipeline 6. The electric heating wire 52 heats the liquid inside the housing 51, and the booster pump 53 delivers the heated liquid to the circulating heat exchange pipeline 6, achieving liquid circulation. Filters 54 are installed at both the outlet of the circulating heat exchange pipeline 6 and the inlet of the booster pump 53. The filters 54 remove impurities from the liquid.

[0026] A liquid tank 55 is connected to the housing 51 via a pipeline, and a first valve 56 is connected to the pipeline between the liquid tank 55 and the housing 51. The liquid tank 55 supplies liquid to the housing 51, and the passage between the liquid tank 55 and the housing 51 is controlled by the first valve 56.

[0027] The tank 51 is equipped with a low level gauge 57 and a high level gauge 58. The liquid in the tank 51 needs to be maintained between the low and high levels. When the liquid level is too low, liquid is added to the tank 51 through the liquid tank 55, and the liquid level does not exceed the high level when adding liquid.

[0028] A first temperature sensor 59 is installed inside the housing 51. The first temperature sensor 59 can detect the temperature of the liquid inside the housing 51 and control the on / off state of the electric heating wire 52 according to the liquid temperature.

[0029] The instrument air duct 4 is connected to several drain connectors 41, and each drain connector 41 is connected to a shut-off valve 42; each drain connector 41 is connected to a liquid sensor 43. When the liquid sensor 43 detects water accumulation in the drain connector 41, it opens the shut-off valve 42 to drain the water.

[0030] A fluid sensor 44 is connected to the instrument air duct 4. The fluid sensor 44 can automatically detect whether the fluid in the instrument air duct 4 is in a flowing state or a stationary state.

[0031] A second temperature sensor 45 is connected to the instrument air duct 4. The second temperature sensor 45 can detect the temperature of the compressed air inside the instrument air duct 4 and control whether the heating unit 5 needs to be activated based on the collected temperature.

[0032] A purge pipe 8 is connected to the section of the circulating heat exchange pipe 6 before it enters the instrument air duct 4. After the air in the instrument air duct 4 is heated by the heating unit 5, the liquid in the circulating heat exchange pipe 6 is purged into the housing 51 through the purge pipe 8 to prevent the liquid in the circulating heat exchange pipe 6 from freezing. A second valve 61 is connected to the inlet end of the circulating heat exchange pipe 6, and a third valve 81 is connected to the purge pipe 8.

[0033] This utility model also includes a PLC control system 7, and the first valve 56, the second valve 61, the third valve 81, the booster pump 53, the high level gauge 58, the low level gauge 57, the first temperature sensor 59, the second temperature sensor 45, the shut-off valve 42, the liquid sensor 43, and the fluid sensor 44 are all electrically connected to the PLC control system 7.

[0034] The feedback from the fluid sensor 44 enables automatic detection of whether the fluid in the instrument air duct 4 is in a flowing or static state. Combined with the temperature collected by the second temperature sensor 45, the PLC control system 7 controls whether the heating and heat exchange function needs to be activated.

[0035] Feedback from the liquid sensor 43 enables automatic detection of excessive liquid accumulation in low-lying areas of the pipeline (indicating high water content). If the accumulation exceeds the limit, the PLC control system 7 directly controls the opening of the shut-off valve 42 to drain the liquid from the bottom of the pipeline. If the collected value is not in a liquid state, and the temperature detected by the second temperature sensor 45 is lower than the set value, the PLC control system 7 activates the heating and heat exchange function to melt the ice in the pipeline. After melting, the collected value becomes liquid again, and the PLC control system 7 controls the opening of the shut-off valve 42 to drain the melted liquid from the bottom of the pipeline. In this embodiment, there are three drain connectors 41, located at the inlet, middle, and outlet sections of the instrument air duct 4.

[0036] The PLC control system 7 controls the opening and closing of the second valve 61 to realize the function of circulating heat exchange pipeline 6 in the instrument air duct 4 as needed, and bringing in heat to heat and liquefy the ice in the pipeline.

[0037] The housing 51 is equipped with a first temperature transmitter, a low level gauge 57, and a high level gauge 58, which are linked to control the first valve 56 to replenish the liquid level in the housing 51 and automatically start and stop the heating.

[0038] The circulating heating device of the compressed gas supply system for LNG refueling stations is safe and reliable. It changes the previous problem of ice blockage caused by untimely manual discharge. Instead, it uses a PLC system to automatically control the discharge and heating functions, which is more automated, more energy-efficient, safe and reliable, and prevents safety accidents.

[0039] This utility model is not limited to the above-mentioned optional embodiments. Anyone can derive other forms of products under the guidance of this utility model. However, regardless of any changes made in its shape or structure, any technical solution that falls within the scope of the claims of this utility model shall be protected by this utility model.

Claims

1. A circulating heat exchange device for a compressed gas supply system in an LNG refueling station, comprising a compressed air system (1), an LNG pump skid (2), and a refueling machine (3), wherein an instrument air duct (4) connects the compressed air system (1), the LNG pump skid (2), and the refueling machine (3); characterized in that: It also includes a heating unit (5), which contains a liquid for heat exchange. A circulating heat exchange pipeline (6) is installed inside the instrument air duct (4), and the inlet and outlet of the circulating heat exchange pipeline (6) are connected to the heating unit (5).

2. The circulating heat exchange device for an LNG refueling station compressed gas supply system according to claim 1, characterized in that: The heating unit (5) includes a housing (51), liquid is placed inside the housing (51), an electric heating wire (52) is installed inside the housing (51), a booster pump (53) is installed on the housing (51), and the outlet of the booster pump (53) is connected to the inlet of the circulating heat exchange pipeline (6).

3. The circulating heat exchange device for an LNG refueling station compressed gas supply system according to claim 2, characterized in that: A liquid tank (55) is connected to the box body (51) via a pipeline, and a first valve (56) is connected to the pipeline between the liquid tank (55) and the box body (51).

4. The circulating heat exchange device for an LNG refueling station compressed gas supply system according to claim 3, characterized in that: The housing (51) is equipped with a low level gauge (57) and a high level gauge (58).

5. A circulating heat exchange device for an LNG refueling station compressed gas supply system according to claim 2, characterized in that: The first temperature sensor (59) is installed inside the housing (51).

6. A circulating heat exchange device for an LNG refueling station compressed gas supply system according to claim 2, characterized in that: The outlet of the circulating heat exchange pipeline (6) and the inlet of the booster pump (53) are both equipped with filters (54).

7. The circulating heat exchange device for an LNG refueling station compressed gas supply system according to claim 1, characterized in that: The instrument air duct (4) is connected to several drain joints (41), and a shut-off valve (42) is connected to the drain joints (41); a liquid sensor (43) is connected to the drain joints (41).

8. A circulating heat exchange device for an LNG refueling station compressed gas supply system according to claim 7, characterized in that: A fluid sensor (44) is connected to the instrument air duct (4).

9. A circulating heat exchange device for an LNG refueling station compressed gas supply system according to claim 7, characterized in that: A second temperature sensor (45) is connected to the instrument air duct (4).

10. A circulating heat exchange device for an LNG refueling station compressed gas supply system according to any one of claims 1 to 9, characterized in that: The section of the circulating heat exchange pipeline (6) before entering the instrument air duct (4) is connected to a purging pipeline (8).

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