A pumpless filling system for liquefied gas

Abstract

A pump-free filling system for liquefied gas belongs to the field of liquefied gas filling pressure container equipment; in order to solve the problems existing in the pump delivery method and the differential pressure filling method, the utility model provides a pump-free self-circulation filling system; the system comprises a first low-temperature storage tank, a second low-temperature storage tank and a gasifier, the first low-temperature storage tank bottom liquid outlet is communicated with the second low-temperature storage tank liquid inlet through a valve, the second low-temperature storage tank bottom liquid outlet is communicated with the to-be-filled container liquid inlet through a valve, the to-be-filled container top gas outlet is communicated with the second heat exchange device inlet, the outlet is communicated with the first heat exchange device inlet through a valve, the first heat exchange device outlet is communicated with the first low-temperature storage tank storage cavity, the gasifier inlet is communicated with the second low-temperature storage tank bottom liquid outlet, and the outlet is communicated with the gas inlet; through gas-liquid heat exchange circulation, the liquefied gas is self-pressurized and delivered, a liquid pump is not needed, and a pressure, liquid level detection and safety protection device are simultaneously arranged.

Description

Technical Field

[0001] This application relates to liquefied gas filling equipment, specifically to a pumpless liquefied gas filling system. Background Technology

[0002] To inject liquefied gas from a cryogenic storage tank into a container to be filled, pump delivery or differential pressure filling methods are typically used. However, pump delivery methods have technical problems such as high energy consumption, high maintenance costs, and the heat generated during pump operation causing the liquefied gas to vaporize and be discharged from the container.

[0003] Compared to the pumping method, the differential pressure filling method reduces the cost of use by eliminating the need for a cryogenic liquid pump. For example, Chinese patent documents filed on August 3, 2015, with publication number CN106402643A, and filed on January 16, 2018, with publication number CN108204078A, both disclose a pumpless air-source cryogenic liquefied gas filling system using the differential pressure filling method. Differential pressure refueling method usually requires venting the gas in the container to be refueled before refueling, so that the subsequent liquefied gas can smoothly enter the container to be refueled; for example, the technical solutions disclosed in CN106402643A and CN108204078A are to install a vent pipe on the low-pressure cryogenic storage tank (equivalent to the container to be refueled) for venting the low-pressure cryogenic storage tank; Therefore, although differential pressure filling avoids the energy consumption problem of pumping, it is still a lossy filling method in essence. During the filling of liquefied gas, the precious gas in the container to be filled must be discharged to the outside. This may not only cause product waste, but also pose safety hazards and environmental problems, especially in certain situations. Utility Model Content

[0004] The purpose of this invention is to provide a pumpless liquefied gas filling system. Utilizing the interconnected structure and heat exchange cycle principle between the first cryogenic storage tank, the second cryogenic storage tank, and the vaporizer, a self-circulating filling method formed by vaporization and pressurization is used to achieve automatic delivery and filling of liquefied gas under pumpless conditions. This solves the technical problems existing in the pump delivery method and differential pressure filling method in the prior art, and produces the beneficial effect of achieving efficient, safe, and energy-saving filling of liquefied gas without the need for pumping equipment.

[0005] To achieve the aforementioned objectives, the technical solution adopted by this utility model is as follows: A pumpless liquefied gas filling system includes a first cryogenic storage tank, a second cryogenic storage tank, and a vaporizer; The bottom outlet of the first cryogenic storage tank is connected to the inlet of the second cryogenic storage tank through a first valve, and the bottom outlet of the second cryogenic storage tank is connected to the inlet of the container to be filled through a sixth valve. The top vent of the container to be filled is connected to the inlet of the second heat exchange device provided in the storage chamber of the second cryogenic storage tank. The outlet of the second heat exchange device is connected to the inlet of the first heat exchange device provided in the first cryogenic storage tank through a third valve. The outlet of the first heat exchange device is connected to the storage chamber of the first cryogenic storage tank. The inlet of the vaporizer is connected to the bottom liquid outlet of the second cryogenic storage tank through a fifth valve, and its outlet is connected to the air inlet of the second cryogenic storage tank. The top outlet of the second cryogenic storage tank is connected to the air inlet of the first cryogenic storage tank and the inlet of the first heat exchange device through the second valve and the fourth valve, respectively.

[0006] Preferably, it further includes a filling device for filling the first cryogenic storage tank with liquefied gas, the filling device including an unloading booster and an unloading pipeline; The gas phase port and the pressurization port of the transport tanker are respectively connected to the corresponding interfaces of the unloading pressurizer, and the liquid outlet of the transport tanker is connected to the storage chamber of the first cryogenic storage tank through the unloading pipeline. The unloading pipeline is equipped with an unloading valve.

[0007] Preferably, the first heat exchange device and / or the second heat exchange device are coil heat exchangers.

[0008] Preferably, the first cryogenic storage tank and / or the second cryogenic storage tank are equipped with pressure detectors and / or liquid level detectors.

[0009] Preferably, the first cryogenic storage tank and / or the second cryogenic storage tank are double-walled vacuum insulated storage tanks.

[0010] Preferably, when the first cryogenic storage tank and / or the second cryogenic storage tank are double-walled vacuum insulated storage tanks, their outer shells are provided with evacuation ports for extracting gas between the inner shell and the outer shell.

[0011] Preferably, the first cryogenic storage tank and / or the second cryogenic storage tank are equipped with an overflow valve.

[0012] Preferably, the first cryogenic storage tank and / or the second cryogenic storage tank are equipped with safety valves.

[0013] Preferably, the first cryogenic storage tank and / or the second cryogenic storage tank are equipped with explosion-proof pressure relief devices.

[0014] The beneficial effects of this utility model are: 1. Achieve pump-free self-circulation refueling of liquefied gas, reducing energy consumption and maintenance costs: The vaporizer vaporizes the liquid phase in the second cryogenic storage tank and reinjects the generated gas phase, thereby pressurizing the second cryogenic storage tank. This makes the pressure in the second cryogenic storage tank greater than the pressure in the container to be refueled, which is greater than the pressure in the first cryogenic storage tank, allowing the liquefied gas in the second cryogenic storage tank to enter the container to be refueled. At the same time, the gas in the container to be refueled returns to the first cryogenic storage tank in liquid form after passing through a heat exchange device.

[0015] 2. Avoiding resource waste and safety hazards caused by gas emissions: During the filling process, this system utilizes the gas-liquid phase heat exchange cycle between the second cryogenic storage tank and the first cryogenic storage tank to recover the gas in the container to be filled and participate in heat exchange and pressurization, instead of directly emitting it to the outside. Compared with the venting differential pressure filling system disclosed in CN106402643A and CN108204078A, this utility model avoids the emission of valuable gases, reduces resource waste, lowers potential environmental pollution and deflagration risks, and is safer. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of this application; Figure 2 This is a schematic diagram of the structure of Embodiment 2 of this application.

[0018] Wherein, 1-first cryogenic storage tank, 2-second cryogenic storage tank, 3-vaporizer, 4-first valve, 5-sixth valve, 6-container to be filled, 7-second heat exchanger, 8-third valve, 9-first heat exchanger, 10-fifth valve, 11-second valve, 12-fourth valve, 13-unloading booster, 14-unloading pipeline, 15-unloading valve, 16-pressure detector, 17-level detector, 18-evacuation port, 19-overflow valve, 20-explosion-proof pressure relief device, 21-safety valve. Detailed Implementation

[0019] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0020] The following disclosure provides many different embodiments or examples for implementing various structures of this invention. To simplify the disclosure, specific examples of components and arrangements are described below. Of course, these are merely examples and are not intended to limit the scope of this invention.

[0021] The embodiments of the utility model will now be described in detail with reference to the accompanying drawings.

[0022] Example 1

[0023] See appendix Figure 1 A pumpless liquefied gas filling system includes a first cryogenic storage tank 1, a second cryogenic storage tank 2, and a vaporizer 3; wherein the first cryogenic storage tank 1 and the second cryogenic storage tank 2 are used to store liquid-phase liquefied gas or gas-liquid two-phase liquefied gas, and both should be pressure vessels capable of withstanding a certain pressure; wherein the function of the vaporizer 3 is to vaporize the liquid-phase fluid into the corresponding gas-phase fluid.

[0024] The bottom outlet of the first cryogenic storage tank 1 is connected to the inlet of the second cryogenic storage tank 2 via a pipeline through the first valve 4, and the bottom outlet of the second cryogenic storage tank 2 is connected to the inlet of the container to be filled 6 via a pipeline through the sixth valve 5.

[0025] The top outlet of the container to be filled 6 is connected to the inlet of the second heat exchange device 7 provided in the storage cavity of the second cryogenic storage tank 2 through a pipeline. The outlet of the second heat exchange device 7 is connected to the inlet of the first heat exchange device 9 provided in the first cryogenic storage tank 1 through a pipeline via a third valve 8. The outlet of the first heat exchange device 9 is connected to the storage cavity of the first cryogenic storage tank 1 through a pipeline. In this application, the first heat exchange device 9 and / or the second heat exchange device 7 are specifically selected as coil heat exchangers, wherein the coil of the coil heat exchanger should be immersed in the liquid phase liquefied gas of the corresponding storage tank, so that the fluid in the coil and the liquefied gas in the storage tank can exchange heat, thereby liquefying the gas phase fluid in the coil. After passing through the two coils, the fluid is finally discharged into the first low temperature storage tank 1 as a liquid phase. The inlet of vaporizer 3 is connected to the bottom liquid outlet of the second cryogenic storage tank 2 through a pipeline via the fifth valve 10, and its outlet is connected to the air inlet of the second cryogenic storage tank 2 through a pipeline. This causes the internal pressure of the second cryogenic storage tank 2 to be greater than the internal pressure of the container to be filled 6, and the internal pressure of the container to be filled 6 to be greater than the internal pressure of the first cryogenic storage tank 1, so that the liquefied gas in the second cryogenic storage tank 2 enters the container to be filled 6. Furthermore, coil heat exchangers are just one specific choice of heat exchange device. Their core function is to provide sufficient heat exchange area to achieve efficient heat exchange between the fluids inside and outside the tube. Heat exchange devices can also be configured as shell-and-tube heat exchangers, coiled tube heat exchangers, or any other equivalent structure that can achieve heat exchange.

[0026] The top outlet of the second cryogenic storage tank 2 is connected to the air inlet of the first cryogenic storage tank 1 and the inlet of the first heat exchange device 9 via pipelines through the second valve 11 and the fourth valve 12, respectively.

[0027] The pumpless liquefied gas filling system described in this embodiment is used as follows: Step S1: Filling the second storage tank with liquid from the first storage tank: Open the first valve 4 and the second valve 11; the liquefied gas in the first cryogenic storage tank 1 enters the second cryogenic storage tank 2 under the action of the communicating vessel principle; when the liquid level in the second cryogenic storage tank 2 reaches the appropriate level, close the first valve 4 and the second valve 11.

[0028] Step S2: Pressurize the second storage tank: Open the fifth valve 10; the liquefied gas in the second cryogenic storage tank 2 flows through the vaporizer 3 and is vaporized, then returns to the gas phase space of the second cryogenic storage tank 2 to achieve self-pressurization; when the pressure of the second cryogenic storage tank 2 reaches the suitable pressure, close the fifth valve 10. When the second cryogenic storage tank 2 is equipped with a pressure detector 16, the opening and closing timing of the fifth valve 10 is determined by the pressure detector 16 of the second cryogenic storage tank 2.

[0029] Step S3: Fill the container to be filled: Open the sixth valve 5 and the third valve 8; the liquefied gas flows into the container to be filled 6 through the sixth valve 5 under the pressure difference between the second cryogenic storage tank 2 and the first storage tank; at the same time, the gas displaced in the container to be filled 6 flows sequentially through the second heat exchange device 7 (and is cooled and liquefied in the second storage tank), the third valve 8, and the first heat exchange device 9 (and is deeply cooled and liquefied in the first storage tank), and finally mixes with the liquefied gas in the first cryogenic storage tank 1; after filling is completed, close the sixth valve 5.

[0030] Step S4: Pressure balancing and cycle operation: When the liquid level in the second cryogenic storage tank 2 is lower than the appropriate liquid level, the fourth valve 12 can be opened to allow the gas in the second cryogenic storage tank 2 to flow through the fourth valve 12, the third valve 8, and the first heat exchange device 9 and be liquefied, thereby reducing the pressure of the second cryogenic storage tank 2; when the pressure of the two tanks reaches a suitable balance state (i.e., the pressure of the second tank is slightly higher than the pressure of the first tank), step S1 can be executed again to start the next filling cycle.

[0031] Example 2 See appendix Figure 2 Based on the above embodiment 1, this embodiment adds a filling device for filling the first cryogenic storage tank 1 with liquefied gas, wherein the filling device includes an unloading booster 13 and an unloading pipeline 14. The gas phase port and the booster port of the transport tanker are respectively connected to the interfaces corresponding to the unloading booster 13 through pipelines, and the liquid outlet of the transport tanker is connected to the storage cavity of the first cryogenic storage tank 1 through the unloading pipeline 14. The unloading pipeline 14 is equipped with an unloading valve 15.

[0032] The method of using the filling device is as follows: connect the transport tanker to the system, open the unloading booster 13 and the unloading valve 15, and use the pressure difference to fill the liquefied gas in the tanker into the first cryogenic storage tank 1 through the unloading pipeline 14.

[0033] In order to better achieve the inventive objective of this application, the following common improvements are made to the above-described embodiments 1 and 2: Pressure detector 16 and / or liquid level detector 17 are provided on the first cryogenic storage tank 1 and / or the second cryogenic storage tank 2; Among them, the liquid level detector 17 is used to monitor the liquid level height in the storage tank in real time; Among them, the pressure detector 16 is used to monitor the pressure value inside the storage tank in real time.

[0034] The first cryogenic storage tank 1 and / or the second cryogenic storage tank 2 are double-layer vacuum insulated storage tanks. In this embodiment, double-layer insulated cryogenic storage tanks are selected. The outer shell of the double-layer insulated cryogenic storage tank or multi-layer cryogenic insulated storage tank is provided with an evacuation port 18 for extracting gas between the inner shell and the outer shell, which serves to perform vacuum insulation.

[0035] An overflow valve 19 is provided on the first cryogenic storage tank 1 and / or the second cryogenic storage tank 2; The liquid level in the first cryogenic storage tank 1 and / or the second cryogenic storage tank 2 can be manually detected through the overflow valve 19.

[0036] Safety valves 21 are provided on the first cryogenic storage tank 1 and / or the second cryogenic storage tank 2; Among them, safety valve 21 is used to automatically open when the pressure of the storage tank exceeds the design safety threshold, release excess gas, prevent the storage tank from bursting or being damaged, enable the system to operate stably, and avoid operation interruption or safety accidents caused by overpressure. In addition, the safety valve 21 can be directly installed on the tank body of the first cryogenic storage tank 1 and / or the second cryogenic storage tank 2, or it can be installed on the pipeline connected to the first cryogenic storage tank 1 and / or the second cryogenic storage tank 2. However, when the safety valve 21 is installed on the pipeline connected to the first cryogenic storage tank 1 and / or the second cryogenic storage tank 2, no valve should be installed between the safety valve 21 and the storage cavity of the first cryogenic storage tank 1 and / or the second cryogenic storage tank 2.

[0037] The first cryogenic storage tank 1 and / or the second cryogenic storage tank 2 are equipped with explosion-proof pressure relief devices 20; The explosion-proof pressure relief device 20 can be specifically selected as a rupture disc (also known as an explosion-proof disc or explosion-proof membrane). It is a non-reclosable safety pressure relief device composed of a rupture disc and a clamp. It achieves rapid pressure relief by breaking the diaphragm at a set pressure and temperature, which can prevent pressure vessels or pipelines from being damaged by overpressure.

[0038] The above specific embodiments further illustrate the purpose, technical solution and beneficial effects of this utility model. It should be understood that the above are only specific embodiments of this utility model and are not intended to limit the scope of protection of this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. A pumpless liquefied gas dispensing system, characterized in that: It includes a first cryogenic storage tank (1), a second cryogenic storage tank (2), and a vaporizer (3); The bottom outlet of the first cryogenic storage tank (1) is connected to the inlet of the second cryogenic storage tank (2) through the first valve (4), and the bottom outlet of the second cryogenic storage tank (2) is connected to the inlet of the container to be filled (6) through the sixth valve (5). The top vent of the container to be filled (6) is connected to the inlet of the second heat exchange device (7) provided in the storage cavity of the second cryogenic storage tank (2). The outlet of the second heat exchange device (7) is connected to the inlet of the first heat exchange device (9) provided in the first cryogenic storage tank (1) through the third valve (8). The outlet of the first heat exchange device (9) is connected to the storage cavity of the first cryogenic storage tank (1). The inlet of the vaporizer (3) is connected to the bottom outlet of the second cryogenic storage tank (2) through the fifth valve (10), and its outlet is connected to the air inlet of the second cryogenic storage tank (2). The top outlet of the second cryogenic storage tank (2) is connected to the air inlet of the first cryogenic storage tank (1) and the inlet of the first heat exchange device (9) through the second valve (11) and the fourth valve (12), respectively.

2. The pumpless liquefied gas filling system as described in claim 1, characterized in that: It also includes a filling device for filling the first cryogenic storage tank (1) with liquefied gas, the filling device including an unloading booster (13) and an unloading pipeline (14). The gas phase port and the booster port of the transport tanker are respectively connected to the corresponding interfaces of the unloading booster (13), and the liquid outlet of the transport tanker is connected to the storage cavity of the first cryogenic storage tank (1) through the unloading pipeline (14). The unloading pipeline (14) is equipped with an unloading valve (15).

3. The pumpless liquefied gas filling system as described in claim 1, characterized in that: The first heat exchange device (9) and / or the second heat exchange device (7) are coil heat exchangers.

4. The pumpless liquefied gas filling system as described in claim 1, characterized in that: The first cryogenic storage tank (1) and / or the second cryogenic storage tank (2) are equipped with a pressure detector (16) and / or a liquid level detector (17).

5. The pumpless liquefied gas filling system as described in claim 1, characterized in that: The first cryogenic storage tank (1) and / or the second cryogenic storage tank (2) are double-layer vacuum insulated storage tanks.

6. The pumpless liquefied gas filling system as described in claim 5, characterized in that: When the first cryogenic storage tank (1) and / or the second cryogenic storage tank (2) are double-layer vacuum insulated storage tanks, their outer shells are provided with evacuation ports (18) for extracting gas between the inner shell and the outer shell.

7. The pumpless liquefied gas filling system as described in claim 1, characterized in that: An overflow valve (19) is provided on the first cryogenic storage tank (1) and / or the second cryogenic storage tank (2).

8. The pumpless liquefied gas filling system as described in claim 1, characterized in that: Safety valves (21) are provided on the first cryogenic storage tank (1) and / or the second cryogenic storage tank (2).

9. The pumpless liquefied gas filling system as described in claim 1, characterized in that: The first cryogenic storage tank (1) and / or the second cryogenic storage tank (2) are equipped with explosion-proof pressure relief devices (20).

Images