CN220669152U

CN220669152U - Liquefaction system for maintaining ammonia fuel in ammonia fuel tank and ammonia fuel storage device

Info

Publication number: CN220669152U
Application number: CN202322261436.3U
Authority: CN
Inventors: 刘书杨; 白玉刚; 严彦涛; 陈强; 李成文; 成杰
Original assignee: China Ship Design & Research Center Co ltd
Current assignee: China Ship Design & Research Center Co ltd
Priority date: 2023-08-22
Filing date: 2023-08-22
Publication date: 2024-03-26
Anticipated expiration: 2033-08-22

Abstract

The application discloses a liquefaction system and an ammonia fuel storage device for maintaining ammonia fuel in an ammonia fuel tank. The system comprises a cooling coil 2 arranged in the upper space of an ammonia fuel tank 1; one end of the cooling coil pipe 2 is connected with a medium inlet of the cold end of the ammonia refrigerator 3 through a first pipeline 5, and the other end of the cooling coil pipe 2 is connected with a cooling medium outlet of the cold end of the ammonia refrigerator 3 through a second pipeline 4; the heat dissipation end of the ammonia refrigerator 3 is connected with a cooling water pipeline 6. The ammonia vapor inside the ammonia fuel tank is cooled and liquefied by the ammonia refrigerator directly, so that the toxicity and explosion risk of the released vapor of the ammonia tank are eliminated at lower cost. The system provided by the application is simple, safe and reliable; and the initial investment cost is low, and the operation cost is low.

Description

Liquefaction system for maintaining ammonia fuel in ammonia fuel tank and ammonia fuel storage device

Technical Field

The present application relates to the field of marine technology, and in particular, to a liquefaction system and an ammonia fuel storage device for maintaining ammonia fuel in an ammonia fuel tank.

Background

The ammonia fuel is used as one of the alternative fuels of ship fuel, and has the characteristics of zero carbon emission, good availability and lower storage requirement than LNG. However, because the low-temperature tank is adopted for storing ammonia fuel in the ship, in the storage process, the liquid ammonia absorbs heat and evaporates continuously, so that the pressure in the tank is increased continuously, and the risk that ammonia is released through the safety valve is increased. This release is on the one hand a loss of fuel and more importantly a potential hazard to crew health and life safety. Therefore, it is crucial to equip the liquefaction system to maintain the ammonia fuel in the ammonia fuel tank to eliminate this risk.

In view of the above, the ammonia vapor in the tank is directly cooled and liquefied by adopting an ammonia refrigeration method by combining the physical properties of ammonia, so that the toxicity and explosion risk of the vapor released by the ammonia tank are eliminated at lower cost.

Disclosure of Invention

The application provides a liquefaction system and an ammonia fuel storage device for maintaining ammonia fuel in an ammonia fuel tank so as to realize the purposes of controlling the pressure in the ammonia fuel tank and avoiding the safety risk caused by the release of ammonia vapor overpressure.

In order to achieve the above purpose, the present application adopts the following technical scheme:

a cooling coil 2 disposed in an upper space in the ammonia fuel tank 1; one end of the cooling coil pipe 2 is connected with a medium inlet of the cold end of the ammonia refrigerator 3 through a first pipeline 5, and the other end of the cooling coil pipe 2 is connected with a cooling medium outlet of the cold end of the ammonia refrigerator 3 through a second pipeline 4; the heat dissipation end of the ammonia refrigerator 3 is connected with a cooling water pipeline 6.

By the above, the ammonia vapor in the ammonia fuel tank 1 is cooled and liquefied by the ammonia refrigerator 3 directly by adopting an ammonia refrigeration method, so that the toxicity and explosion risk of the vapor released by the ammonia tank are eliminated at lower cost.

Optionally, the first line 5 is provided with a pressure sensor 7 at the outside of the ammonia fuel tank 1.

From the above, the working pressure of the cooling coil 2 should always be higher than the design pressure of the ammonia fuel tank 1, and the pressure sensor 7 monitors the pressure of the cooling coil 2, and when the pressure of the cooling coil 2 during working is lower than the design pressure of the ammonia fuel tank 1, the pressure sensor 7 gives out a low-pressure alarm. The pressure in the cooling coil 2 is higher than the pressure in the ammonia fuel tank 1, so that the risk of ammonia vapor leaking into the cooling coil 2 can be avoided.

Optionally, the second pipe 4 is covered with a heat insulating layer.

From above, the second pipeline 4 is conveyed to a lower level Wen Yean, so that the outer layer of the pipeline needs to be covered with a heat insulation layer.

Alternatively, the cooling coil 2 employs a serpentine coil.

By the above, the cooling coil 2 adopted in the ammonia fuel tank 1 adopts the serpentine coil, so that the contact area with the gas space is increased, and meanwhile, the pressure in the ammonia fuel tank 1 can be maintained at 1.0-2.0Barg, thereby avoiding the extra leakage risk of ammonia steam.

Optionally, the ammonia fuel tank 1 is sealed at the inlet and outlet pipe orifice by welding with the cooling coil 2.

From the top, the cooling coil 2 and the first pipeline 5 and the second pipeline 4 belong to the same pipeline, the inside of the ammonia fuel tank 1 is coiled and arranged in a serpentine way to form the cooling coil 2, the cooling coil 2 is arranged at the upper part of the ammonia fuel tank 1 in and out, and the pipe opening in and out of the ammonia fuel tank 1 is connected in a sealing way, so as to avoid the leakage of ammonia vapor.

Optionally, the ammonia refrigerator 3 has a heat exchange structure inside, the condensation side of the heat exchange structure is connected to the cooling water pipeline 6 through the heat dissipation end of the ammonia refrigerator 3, and the condensed side of the heat exchange structure is connected to the first pipeline 5 and the second pipeline 4, respectively.

From above, cooling water enters the ammonia refrigerator 3 through the cooling water pipeline 6, ammonia gas or gas-liquid mixture from the first pipeline 5 is subjected to cooling treatment through a heat exchange structure to obtain low Wen Yean (the temperature is about-20 ℃), low-temperature liquid ammonia enters the ammonia storage, and then liquid is forcibly fed through the expansion valve and the ammonia pump in sequence, and is conveyed to the cooling coil 2 through the second pipeline 4 for heat absorption.

The present application proposes an ammonia fuel storage device comprising:

an ammonia fuel tank 1 and any one of the above-described liquefaction systems for maintaining ammonia fuel in an ammonia fuel tank.

By the above, the liquefaction system for maintaining the ammonia fuel in the ammonia fuel tank designed by the application is simple, safe and reliable, and has low initial investment cost and low operation cost.

In summary, the ammonia vapor in the ammonia tank is directly cooled and liquefied by adopting the ammonia refrigeration method by combining physical properties of ammonia, so that toxicity and explosion risk of the ammonia tank releasing vapor are eliminated at lower cost.

Drawings

The individual technical features of the present application and their relationships are further described below with reference to the accompanying drawings. The drawings are exemplary, some technical features are not shown in actual proportion, and some drawings may omit technical features that are conventional in the art to which the present application pertains and are not essential to understanding and realizing the present application, or additionally show technical features that are not essential to understanding and realizing the present application, that is, combinations of the technical features shown in the drawings are not limiting the present application. In addition, throughout this application, like reference numerals refer to like elements. The specific drawings are as follows:

fig. 1 is a block diagram of a liquefaction system for maintaining an ammonia fuel in an ammonia fuel tank in the present application.

Description of the reference numerals

The device comprises an ammonia fuel tank, a 2-cooling coil, a 3-ammonia refrigerator, a 4-second pipeline, a 5-first pipeline, a 6-cooling water pipeline and a 7-pressure sensor.

Specific embodiments thereof have been shown by way of example in the drawings and will herein be described in more detail. These drawings and the written description are not intended to limit the scope of the inventive concepts in any way, but to illustrate the concepts of the present application to those skilled in the art by reference to specific embodiments.

Detailed Description

The preferred embodiments of the present application will be described in detail below with reference to the drawings so that the advantages and features of the present application can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present application.

It is noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising … …" does not exclude the presence of other like elements in a process, method, article or apparatus that comprises the element.

The method is mainly applied to cooling and liquefying of the Boil-Off Gas (BOG) of the ammonia fuel tank so as to achieve the purposes of controlling the pressure in the tank and avoiding the safety risk caused by the release of the ammonia vapor over pressure.

The following describes the technical solution of the present application and how the technical solution of the present application solves the above technical problems in detail with specific embodiments. The specific embodiments described below may be combined with one another to form new embodiments. The same or similar ideas or processes described in one embodiment may not be repeated in certain other embodiments. Embodiments of the present application will be described below with reference to the accompanying drawings.

Fig. 1 is a block diagram of a liquefaction system for maintaining an ammonia fuel in an ammonia fuel tank according to the present application, and as shown in fig. 1, the liquefaction system for maintaining an ammonia fuel in an ammonia fuel tank provided by the present application includes: a cooling coil 2 disposed in an upper space in the ammonia fuel tank 1; one end of the cooling coil pipe 2 is connected with a medium inlet of the cold end of the ammonia refrigerator 3 through a first pipeline 5, and the other end of the cooling coil pipe 2 is connected with a cooling medium outlet of the cold end of the ammonia refrigerator 3 through a second pipeline 4; the heat dissipation end of the ammonia refrigerator 3 is connected with a cooling water pipeline 6.

Specifically, the ammonia vapor in the ammonia fuel tank 1 is cooled and liquefied by the ammonia refrigerator 3 directly by adopting an ammonia refrigeration method, so that the toxicity and explosion risk of the vapor released by the ammonia tank are eliminated at a lower cost. The system provided by the application is simple, safe and reliable; and the initial investment cost is low, and the operation cost is low.

In a specific embodiment of the present application, a cooling coil 2 is arranged from the space of the inner upper part of the ammonia fuel tank 1, and the cooling medium in the cooling coil 2 is low Wen Yean (temperature about-20 ℃). The cooling coil 2 cools and liquefies the ammonia vapor in the upper portion of the ammonia fuel tank 1, thereby maintaining the pressure of the ammonia fuel tank 1 at about 1.0-2.0 Barg. The cooling coil 2 is adopted in the ammonia fuel tank 1, so that the additional leakage risk of ammonia vapor is avoided.

Specifically, the working pressure of the cooling coil 2 should be always higher than the design pressure of the ammonia fuel tank 1, and the pressure sensor 7 monitors the pressure of the cooling coil 2, and when the pressure of the cooling coil 2 during working is lower than the design pressure of the ammonia fuel tank 1, the pressure sensor 7 gives a low-pressure alarm. The pressure in the cooling coil 2 is higher than the pressure in the ammonia fuel tank 1, so that the risk of ammonia vapor leaking into the cooling coil 2 can be avoided.

It should be noted that, since the first pipeline 5, the second pipeline 4 and the cooling coil 2 are disposed at different positions by the same pipe, the pressure sensor 7 disposed at the outer portion of the ammonia fuel tank 1 of the first pipeline 5 can monitor the working pressure in the cooling coil 2, and the pressure sensor 7 sends out a low-pressure alarm when it is monitored that the working pressure in the cooling coil 2 is lower than the design pressure of the ammonia fuel tank 1.

Alternatively, the cooling coil 2 employs a serpentine coil.

The cooling coil 2 adopted in the ammonia fuel tank 1 adopts a serpentine coil, so that the contact area with the gas space is increased, and meanwhile, the pressure in the ammonia fuel tank 1 can be maintained at 1.0-2.0Barg, and the additional leakage risk of ammonia steam is avoided.

The distance of the cooling coil 2 from the top in the ammonia fuel tank 1 should be as small as possible, which is not particularly limited in this application.

Optionally, the second pipe 4 is covered with a heat insulating layer.

Specifically, the second pipeline 4 is conveyed to a low level Wen Yean, so that the outer layer thereof needs to be covered with a heat insulating layer.

In a specific embodiment of the present application, the refrigerating end of ammonia refrigerator 3 is provided with a medium inlet and a cooling medium outlet; the second pipeline 4 is connected with the ammonia refrigerator 3 through a cooling medium outlet; the first pipeline 5 is connected with the ammonia refrigerator 3 through a medium inlet. The ammonia refrigerator 3 combines the physical property of ammonia, directly adopts an ammonia refrigeration method to prepare a cooling medium, and eliminates the risk of ammonia steam explosion while reducing the system cost.

Specifically, the cooling coil 2 and the first pipeline 5 and the second pipeline 4 belong to the same pipeline, the inside of the ammonia fuel tank 1 is coiled and arranged in a serpentine manner to form the cooling coil 2, the cooling coil 2 is arranged at the upper part of the ammonia fuel tank 1 in and out, and the cooling coil 2 is in sealing connection with the pipe inlet and outlet of the ammonia fuel tank 1 so as to avoid the leakage of ammonia vapor.

Specifically, cooling water enters the ammonia refrigerator 3 through a cooling water pipeline 6, ammonia gas or a gas-liquid mixture from a first pipeline 5 is subjected to cooling treatment through a heat exchange structure to obtain low Wen Yean (the temperature of the low-temperature liquid ammonia is about-20 ℃), low-temperature liquid ammonia enters an ammonia storage device and then is forcibly fed through an expansion valve and an ammonia pump in sequence, and the low-temperature liquid ammonia is conveyed to the cooling coil 2 through a second pipeline 4 for heat absorption.

In a specific embodiment of the present application, the heat exchange structure corresponds to a heat exchanger, the condensing side is cooling water, and the condensed side is ammonia gas or a gas-liquid mixture from the first pipeline 5. The process of condensing the ammonia gas or the gas-liquid mixture at the condensed side comprises the steps of compressing the low-pressure ammonia gas or the gas-liquid mixture into high-pressure gas through a compressor, separating frozen oil mist carried out by the compressor through an ammonia oil separator, condensing the oil mist into high-pressure low Wen Yean (equivalent to a secondary refrigerant) through a condenser, and storing the high-pressure low Wen Yean in an ammonia storage device. The ammonia storage device is used for storing condensed low-temperature liquid ammonia, and adjusting the supply-demand relationship between the cooling coil 2 and the ammonia refrigerator, so that the cooling coil 2 can uninterruptedly cool ammonia steam through the ammonia storage device; the low-temperature liquid ammonia in the ammonia storage device is conveyed into the cooling coil pipe 2 through the second pipeline 4 under the power action of the ammonia pump after being throttled and depressurized by the expansion valve, the cooling coil pipe 2 absorbs the heat of the upper space of the ammonia fuel tank 1, and ammonia vapor is cooled and liquefied, so that the extra leakage of the ammonia vapor is prevented.

Besides the throttling and depressurization effects on the low-temperature liquid ammonia, the expansion valve can also control and regulate the flow rate of the low-temperature liquid ammonia entering the second pipeline 4. When the working pressure of the cooling coil pipe 2 is lower than the design pressure of the ammonia fuel tank 1, the pressure sensor 7 gives out a low-pressure alarm, and the expansion valve increases the flow of low-temperature liquid ammonia (high pressure), so that the working pressure of the cooling coil pipe 2 is always higher than the design pressure of the ammonia fuel tank 1, and the risk that ammonia vapor leaks into the cooling coil pipe 2 can be timely avoided.

In one embodiment, the cooling water line 6 continuously supplies cooling water to the ammonia chiller 3 under the power of a cooling pump.

In one embodiment of the present application, ammonia chiller 3 delivers low temperature liquid ammonia (Wen Yean) (at about-20 ℃) after liquefaction cooling to cooling coil 2 through second tube 4 (also referred to as the liquid ammonia tube) over which insulation is wrapped; the low-temperature liquid ammonia in the cooling coil pipe 2 absorbs heat and becomes ammonia gas or gas-liquid mixture, and the cooling coil pipe 2 cools and liquefies ammonia vapor at the upper part of the ammonia fuel tank 1, so that the pressure of the ammonia fuel tank 1 is maintained at about 1.0-2.0 Barg; the ammonia gas or gas-liquid mixture is returned to the ammonia refrigerator 3 through the first line 5 (also referred to as a high temperature ammonia vapor line) for liquefaction and cooling to a low Wen Yean; wherein the ammonia refrigerator 3 is cooled by cooling water through a cooling water line 6.

In summary, the ammonia vapor in the ammonia tank is directly cooled and liquefied by adopting the ammonia refrigeration method by combining physical properties of ammonia, so that toxicity and explosion risk of the ammonia tank releasing vapor are eliminated at lower cost. The system provided by the application is simple, safe and reliable, and has low initial investment cost and low operation cost.

The present application provides an ammonia fuel storage device, comprising: an ammonia fuel tank 1 and any one of the above-described liquefaction systems for maintaining ammonia fuel in an ammonia fuel tank.

The liquefaction system for maintaining the ammonia fuel in the ammonia fuel tank designed by the application is simple, safe and reliable, and has low initial investment cost and low operation cost. The ammonia vapor recovery device is applied to an ammonia fuel storage tank, is beneficial to popularization of a system, improves operating economy of ships, and can eliminate the risk of extra leakage of ammonia vapor.

Unless defined otherwise, all technical and scientific terms used throughout this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. In the event of inconsistency, the meaning described throughout the application or derived from what is described throughout the application. In addition, the terminology used in the description is for the purpose of describing the embodiments of the present application only and is not intended to be limiting of the present application.

The term "comprising" as used throughout this application should not be construed as limited to what is listed thereafter; it does not exclude other elements or steps. Thus, it should be interpreted as specifying the presence of the stated features, integers, steps or components as referred to, but does not preclude the presence or addition of one or more other features, integers, steps or components, or groups thereof.

Note that the above is only the preferred embodiments of the present application and the technical principles applied. Those skilled in the art will appreciate that the present application is not limited to the particular embodiments described herein, but is capable of numerous obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the present application. Therefore, although the present application has been described in more detail through the above embodiments, the present application is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the technical concept of the present application, which falls within the protection scope of the present application.

Claims

1. A liquefaction system for maintaining an ammonia fuel in an ammonia fuel tank, comprising:

a cooling coil (2) arranged in the upper space of the ammonia fuel tank (1);

one end of the cooling coil (2) is connected with a medium inlet of the refrigerating end of the ammonia refrigerator (3) through a first pipeline (5), and the other end of the cooling coil (2) is connected with a cooling medium outlet of the refrigerating end of the ammonia refrigerator (3) through a second pipeline (4);

the heat dissipation end of the ammonia refrigerator (3) is connected with a cooling water pipeline (6).

2. A liquefaction system maintaining an ammonia fuel in an ammonia fuel tank according to claim 1, characterised in that the first conduit (5) is provided with a pressure sensor (7) at the outside of the ammonia fuel tank (1).

3. A liquefaction system for maintaining an ammonia fuel in an ammonia tank according to claim 1, wherein the second conduit (4) is covered with a heat insulating layer.

4. A liquefaction system for maintaining ammonia fuel in an ammonia fuel tank according to claim 1, wherein the cooling coil (2) is a serpentine coil.

5. A liquefaction system for maintaining ammonia fuel in an ammonia tank according to claim 1, characterised in that the ammonia tank (1) inlet and outlet nozzles are sealed to the cooling coil (2) by welding.

6. The liquefaction system for maintaining ammonia fuel in an ammonia fuel tank according to claim 1, wherein the ammonia refrigerator (3) has a heat exchange structure inside, a condensation side of the heat exchange structure is communicated with the cooling water pipeline (6) through a heat dissipation end of the ammonia refrigerator (3), and condensed sides of the heat exchange structure are respectively connected with the first pipeline (5) and the second pipeline (4).

7. An ammonia fuel storage device, comprising:

an ammonia fuel tank (1);

a liquefaction system for maintaining ammonia fuel in an ammonia fuel tank as defined in any one of claims 1 to 6.