Gas return system and method without open fire combustion during filling of ship LNG C-type tank car

Abstract

The invention relates to a gas return system and method without open fire combustion during filling of a ship LNG (liquefied natural gas) C-type tank car, and the system comprises a ship LNG storage tank, a land LNG transport vehicle and ship gas consumption equipment, the liquefied natural gas storage tank is connected with the land LNG transport vehicle through a filling pipeline, and the ship LNG C-type tank car is connected with the ship LNG storage tank. The liquefied natural gas storage tank on the ship is connected with the gas consumption equipment on the ship through a gas phase pipeline, and the gas consumption equipment on the ship consumes the NG or the mixed gas of the NG and N2 generated in the filling process, so that an open-fire-free working environment in the whole filling process is realized. NG or mixed gas of NG and N2 generated in the whole filling process is consumed through the gas consumption equipment on the ship, the open-fire-free working environment in the whole filling process is achieved, the design principle is simple, and the safety of the filling process is greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of ship LNG filling, and in particular to a return air system and method for filling a ship LNG C-type tank truck without open flame combustion. Background Art

[0002] In recent years, with the growth of LNG fuel ship orders, the first LNG filling solution before the delivery of LNG dual-fuel powered ships has gradually become an important issue that needs to be considered during the construction of LNG powered ships. During the replacement process before LNG filling, a large amount of NG and N2 mixed gas will be produced, and during the filling process, a large amount of NG gas will be produced. In order to ensure the stability of the pressure in the liquid tank, these gases need to be handled in a timely manner.

[0003] like Figure 1 As shown, at present, the return gas treatment during LNG bunkering is mostly carried out through combustion in a shore-side flare tower, which burns an open flame and is located at the same dock as the bunkering tank truck, so the safety is poor. Summary of the invention

[0004] According to the technical problems raised above, a return air system without open flame combustion is provided when a ship LNG C-type tank truck is filled.

[0005] The technical means adopted by the present invention are as follows:

[0006] A return air system without open flame combustion during filling of a ship LNG C-type tank truck comprises a liquefied natural gas storage tank on board, a liquefied natural gas transport vehicle on land and gas consuming equipment on board. The liquefied natural gas storage tank and the liquefied natural gas transport vehicle on land are connected via a filling pipeline, and the liquefied natural gas storage tank on board is connected to the gas consuming equipment on board via a gas phase pipeline. NG or a mixed gas of NG and N2 generated during the filling process is consumed by the gas consuming equipment on board, thereby achieving an operating environment without open flame during the entire filling process.

[0007] Furthermore, the gas-consuming equipment on board includes a boiler system and a generator system.

[0008] Furthermore, the boiler system includes a boiler and a preheating device arranged between the liquefied natural gas storage tank on board the ship and the boiler.

[0009] Furthermore, the power generation system includes a generator, and a gas-liquid separation tank, a BOG compressor, a pressure stabilizing tank, a heat exchange device and a buffer tank are sequentially arranged between the liquefied natural gas storage tank and the generator.

[0010] The present invention also discloses a method for using the above-mentioned air return system without open flame combustion during filling of the ship LNG C-type tank truck, comprising the following steps:

[0011] During the replacement, the LNG transport truck on land uses low-temperature NG to replace the N2 in the LNG tank on board. The return gas is a mixture of NG and N2. After being heated to the temperature required by the boiler by the preheating equipment on board, it is directly supplied to the boiler for combustion and consumption.

[0012] During refueling, LNG is added to the LNG storage tank on the ship through LNG transport vehicles on land. The composition of the return gas during the filling process is NG, which can be burned and consumed in the boiler in the same way as the replacement. Alternatively, the LNG droplets that may exist in the NG can be completely vaporized through the shipyard's gas-liquid separation tank, and the NG is compressed to the pressure required by the generator through a compressor, and the pressure of the NG is stabilized by a pressure regulating tank. It is then heated to the temperature required by the generator through the pre-heating equipment on the ship, and then supplied to the generator for combustion and consumption after entering the buffer tank.

[0013] Compared with the prior art, the present invention has the following advantages: the present invention consumes NG or a mixture of NG and N2 generated during the entire filling process through gas-consuming equipment on board, thereby achieving an open flame-free working environment during the entire filling process. The design principle is simple and greatly improves the safety of the filling process. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0015] Figure 1 It is a schematic diagram of the prior art.

[0016] Figure 2 It is a schematic diagram of the structure of the present invention.

[0017] In the figure: 1. LNG filling pipeline; 2. Gas phase pipeline; 3. Liquefied natural gas storage tank; 4. Preheating equipment; 5. Boiler; 6. Gas-liquid separation tank; 7. BOG compressor; 8. Pressure regulating tank; 9. Heat exchange equipment; 10. Buffer tank; 11. Generator. DETAILED DESCRIPTION

[0018] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0019] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0021] Unless otherwise specifically stated, the relative arrangement of the parts and steps described in these embodiments, the numerical expressions and numerical values ​​do not limit the scope of the present invention. At the same time, it should be clear that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. The technology, methods and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be regarded as part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0022] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention: the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0023] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below their position devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0024] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0025] like Figure 2 As shown, an embodiment of the present invention discloses a return air system without open flame combustion during filling of a ship LNG C-type tank truck, comprising a liquefied natural gas storage tank 3 on board, a liquefied natural gas transport vehicle on land, and gas-consuming equipment on board the ship, wherein the liquefied natural gas storage tank and the liquefied natural gas transport vehicle on land are connected via an LNG filling pipeline 1, and the liquefied natural gas storage tank on board the ship is connected to the gas-consuming equipment on board via a gas phase pipeline 2, and NG or a mixture of NG and N2 generated during the filling process is consumed by the gas-consuming equipment on board the ship, thereby achieving an operating environment without open flame during the entire filling process.

[0026] The gas-consuming equipment on board the ship includes a boiler system and a generator system.

[0027] The boiler system includes a boiler 5 and a preheating device 4 disposed between the liquefied natural gas storage tank on board the ship and the boiler.

[0028] The power generation system comprises a generator 11, and a gas-liquid separation tank 6, a BOG compressor 7, a pressure stabilizing tank 8, a heat exchange device 9 and a buffer tank 10 are sequentially arranged between the liquefied natural gas storage tank and the generator.

[0029] The present invention also discloses a method for using the above-mentioned air return system without open flame combustion during filling of the ship LNG C-type tank truck, comprising the following steps:

[0030] During the replacement, the LNG transport truck on land uses low-temperature NG to replace the N2 in the LNG tank on board. The return gas is a mixture of NG and N2. After being heated to the temperature required by the boiler by the preheating equipment on board, it is directly supplied to the boiler for combustion and consumption.

[0031] During refueling, LNG is added to the LNG storage tank on the ship through LNG transport vehicles on land. The composition of the return gas during the filling process is NG, which can be burned and consumed in the boiler in the same way as the replacement. Alternatively, the LNG droplets that may exist in the NG can be completely vaporized through the shipyard's gas-liquid separation tank, and the NG is compressed to the pressure required by the generator through a compressor, and the pressure of the NG is stabilized by a pressure regulating tank. It is then heated to the temperature required by the generator through the pre-heating equipment on the ship, and then supplied to the generator for combustion and consumption after entering the buffer tank.

[0032] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A return air system for a ship LNG C-type tank truck without open flame combustion during filling, characterized in that: It includes a liquefied natural gas storage tank on board, a liquefied natural gas transport vehicle on land, and gas-consuming equipment on board. The liquefied natural gas storage tank and the liquefied natural gas transport vehicle on land are connected via a filling pipeline, and the liquefied natural gas storage tank on board is connected to the gas-consuming equipment on board via a gas phase pipeline. The NG or a mixture of NG and N2 generated during the filling process is consumed by the gas-consuming equipment on board, thereby achieving an operating environment without open flames during the entire filling process.

2. The air return system for filling a ship LNG C-type tank truck without open flame combustion according to claim 1 is characterized in that: The gas-consuming equipment on board the ship includes a boiler system and a generator system.

3. The air return system for filling a ship LNG C-type tank truck without open flame combustion according to claim 1 is characterized in that: The boiler system comprises a boiler and a preheating device arranged between the liquefied natural gas storage tank on board the ship and the boiler.

4. The air return system for filling a ship LNG C-type tank truck without open flame combustion according to claim 1 is characterized in that: The power generation system comprises a generator, and a gas-liquid separation tank, a BOG compressor, a pressure stabilizing tank, a heat exchange device and a buffer tank are sequentially arranged between the liquefied natural gas storage tank and the generator.

5. A method for using the air return system according to any one of claims 1 to 4, characterized in that: The steps include: During the replacement, the LNG transport truck on land uses low-temperature NG to replace the N2 in the LNG tank on board. The return gas is a mixture of NG and N2. After being heated to the temperature required by the boiler by the preheating equipment on board, it is directly supplied to the boiler for combustion and consumption. During refueling, LNG is added to the LNG storage tank on the ship through LNG transport vehicles on land. The composition of the return gas during the filling process is NG, which can be burned and consumed in the boiler in the same way as the replacement. Alternatively, the LNG droplets that may exist in the NG can be completely vaporized through the shipyard's gas-liquid separation tank, and the NG is compressed to the pressure required by the generator through a compressor, and the pressure of the NG is stabilized by a pressure regulating tank. It is then heated to the temperature required by the generator through the pre-heating equipment on the ship, and then supplied to the generator for combustion and consumption after entering the buffer tank.

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