Combustion device

Abstract

The utility model provides a combustion device for a liquefied natural gas ship. The combustion device comprises at least two sets of gas nozzles, each set of gas nozzles are arranged around the central axis in the circumferential direction at intervals, the distances between the gas nozzles in different sets and the central axis are different, and on the plane perpendicular to the central axis, the central angle corresponding to every two adjacent gas nozzles in the circumferential direction is larger than zero. According to the scheme, the gas nozzles of the combustion device are distributed in a divergent mode relative to the central axis, distribution of the gas nozzles is more uniform, and therefore it is guaranteed that the space and the airflow condition around each gas nozzle are basically the same, and the situation of local overheating or supercooling is avoided. Each gas nozzle can form more stable flames, and the shorter flames and uniform combustion are realized, so that the combustion temperature field is uniformly distributed, the boil-off gas can be fully combusted, and the overall combustion efficiency of the combustor is further improved.

Description

Technical Field

[0001] The utility model relates to the technical field of ship environmental protection, and more specifically to a combustion device. Background Art

[0002] When a liquefied natural gas ship is sailing or loading and unloading liquefied natural gas at the dock, due to the transfer of external heat, the liquid cryogenic liquefied natural gas will evaporate to form evaporation gas. If these evaporation gases are not processed in time, not only will the internal pressure of the cargo hold increase rapidly, threatening the safety of the ship, but also direct emission into the atmosphere will cause serious environmental pollution and exacerbate the greenhouse effect.

[0003] The currently commonly used technical solution in the industry is to configure a dedicated natural gas combustion device to achieve the recycling or safe combustion treatment of the evaporation gas. However, the gas nozzles of the traditional combustion device are arranged unreasonably, the distribution of the combustion temperature field is not uniform, the evaporation gas cannot be fully burned, and the combustion efficiency is low.

[0004] Therefore, it is necessary to provide a combustion device to at least partially solve the above problems. Summary of the Utility Model

[0005] A series of simplified concepts are introduced in the summary of the utility model, which will be further described in detail in the specific implementation section. The summary of the utility model does not mean to attempt to define the key features and essential technical features of the claimed technical solution, nor does it mean to attempt to determine the protection scope of the claimed technical solution.

[0006] To at least partially solve the above problems, the utility model provides a combustion device for a liquefied natural gas ship. The combustion device includes at least two groups of gas nozzles. Each group of gas nozzles is circumferentially spaced around the central axis, and the distances from different groups of gas nozzles to the central axis are different. And in a plane perpendicular to the central axis, the central angle corresponding to two adjacent gas nozzles along the circumferential direction is greater than zero.

[0007] According to the combustion device of the first aspect of the utility model, the gas nozzles of the combustion device form a divergent arrangement relative to the central axis, and the distribution of the gas nozzles is more uniform, thus ensuring that the space and air flow conditions around each gas nozzle are basically the same, avoiding local overheating or overcooling. Each gas nozzle can form a more stable flame, achieve a shorter flame and uniform combustion, so that the distribution of the combustion temperature field is uniform, the evaporation gas can be fully burned, and thus the overall combustion efficiency of the burner is improved.

[0008] Optionally, the number of the gas nozzles located on the outer side in the radial direction is greater than the number of the gas nozzles located on the inner side in the radial direction.

[0009] Optionally, the number of the gas nozzles located outside the radial direction in adjacent groups is twice the number of the gas nozzles located inside the radial direction.

[0010] Optionally, the combustion device further includes a swirler configured to make the air flowing out from above it swirl around the center;

[0011] At least some of the gas nozzles are located above the swirler.

[0012] Optionally, the gas nozzle penetrates from below the swirler to above the swirler, or

[0013] the gas nozzle is located above the swirler.

[0014] Optionally, the number of the gas nozzles located at the outermost side in the radial direction is equal to the number of the blades of the swirler

[0015] Optionally, the installation inclination angle of the blades of the swirler is 30° to 60°; and / or

[0016] The gas nozzle adopts a premixed nozzle, and the ratio of the premixed holes to the non-premixed holes of the premixed nozzle is 1:1.

[0017] Optionally, the combustion device further includes:

[0018] A main gas pipe;

[0019] A gas branch pipe connected between the main gas pipe and the gas nozzle; wherein,

[0020] The gas nozzles in the same group communicate with the same gas branch pipe; and / or

[0021] One gas branch pipe corresponds to one group or multiple groups of the gas nozzles.

[0022] Optionally, the gas branch pipe includes:

[0023] A connecting pipe communicating with the main gas pipe;

[0024] A distribution pipe with which the gas nozzle communicates, at least part of the distribution pipe is configured as an annular structure, and the distribution pipe is arranged circumferentially around the center.

[0025] Optionally, the gas nozzles in adjacent two groups communicate with the same gas branch pipe.

[0026] Optionally, the pipe diameter of the gas branch pipe located in the outer ring is larger than the pipe diameter of the gas branch pipe located in the inner ring.

[0027] Optionally, the combustion device further includes a housing that covers the outside of the swirler and the gas nozzle. The housing is provided with an air inlet for air to flow in, and the air inlet is located at the side and / or bottom of the housing.

[0028] Optionally, the combustion device further includes a combustion chamber, and at least part of the gas nozzle extends from the bottom of the combustion chamber into the interior of the combustion chamber.

[0029] Optionally, the combustion chamber is provided with a cooling air inlet for cooling air to enter. Description of the Drawings

[0030] The following drawings of the embodiments of the present invention are hereby incorporated as part of the present invention for understanding the present invention. The embodiments of the present invention and their descriptions shown in the drawings are used to explain the principles of the present invention. In the drawings,

[0031] Figure 1 is a front view schematic diagram of a combustion device according to a preferred embodiment of the present invention;

[0032] Figure 2 is a top view schematic diagram of a combustion device according to a preferred embodiment of the present invention;

[0033] Figure 3 is a bottom view schematic diagram of a combustion device according to a preferred embodiment of the present invention;

[0034] Figure 4 is a three-dimensional schematic diagram of a swirler according to a preferred embodiment of the present invention;

[0035] Figure 5 is a front view schematic diagram of a combustion device according to a preferred embodiment of the present invention, showing the housing in the figure; and

[0036] Figure 6 is a front view schematic diagram of a combustion device according to a preferred embodiment of the present invention, showing the housing and the combustion chamber in the figure;

[0037] Figure 7 is a bottom view schematic diagram of a combustion device according to a preferred embodiment of the present invention, showing the housing and the combustion chamber in the figure.

[0038] Explanation of Reference Numerals

[0039] 10: Gas nozzle

[0040] 20: Swirler

[0041] 21: Blade

[0042] 30: Gas main pipe

[0043] 40: Gas branch pipe

[0044] 41: Connecting pipe

[0045] 42: Distribution pipe

[0046] 50: Housing

[0047] 51: Air inlet

[0048] 60: Combustion chamber

[0049] 61: Cooling air inlet Detailed implementation manners

[0050] In the following description, a number of specific details are given to provide a more thorough understanding of the present utility model. However, it will be apparent to those skilled in the art that the embodiments of the present utility model may be implemented without one or more of these details. In other instances, some technical features well known to those skilled in the art are not described in order to avoid confusion with the embodiments of the present utility model.

[0051] In this document, ordinal numbers such as "first" and "second" cited in the present utility model are merely identifiers and do not have any other meanings, such as a specific order, etc. Moreover, for example, the term "first component" itself does not imply the existence of a "second component", and the term "second component" itself does not imply the existence of a "first component".

[0052] In this document, "upper", "lower", "front", "rear", "left", "right", etc. are only used to represent the relative positional relationship between relevant parts, rather than defining the absolute positions of these relevant parts.

[0053] In this document, "equal", "same", etc. are not strict mathematical and / or geometric limitations, and also include errors that can be understood by those skilled in the art and are allowed in manufacturing or using, etc.

[0054] Unless otherwise specified, the numerical ranges in this document include not only the entire range between its two endpoints, but also several sub-ranges included therein.

[0055] Now, exemplary embodiments according to the present utility model will be described in more detail with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many different forms and should not be construed as being limited only to the embodiments set forth herein. It should be understood that these embodiments are provided so that the disclosure of the present utility model is thorough and complete, and the concept of these exemplary embodiments is fully conveyed to those of ordinary skill in the art.

[0056] The gas nozzles 10 of the existing combustion device are unreasonably arranged, the combustion temperature field distribution is not uniform, the evaporation gas cannot be fully burned, and the combustion efficiency is low.

[0057] In addition, according to the requirements of the classification society, the flue gas temperature discharged by the combustion device should reach below 450 °C for liquefied natural gas carriers and below 250 °C for fueling ships. To achieve this index, the natural gas combustion device is often equipped with cooling air to dilute and cool the flue gas. After sufficient heat exchange, it is safely discharged. However, the process of mixing the cooling air and the flue gas is not so uniform. Its cooling is limited to the periphery of the flame and cannot fully exchange heat with the inside of the flame. In this way, the flame temperature field distribution is uneven, and the outlet temperature of the natural gas combustion device will be too high, unable to meet the equipment emission requirements.

[0058] The combustion device provided by the present utility model can improve or overcome one or more of the above problems.

[0059] Refer to Figures 1 to 3 , the combustion device includes at least two groups of gas nozzles 10. Each group of gas nozzles 10 is arranged at intervals along the circumferential direction around the central axis. The distances from different groups of gas nozzles 10 to the central axis are different, and in a plane perpendicular to the central axis, the central angle corresponding to two adjacent gas nozzles 10 along the circumferential direction is greater than zero. According to this solution, the gas nozzles 10 of the combustion device form a divergent arrangement relative to the central axis, and the distribution of the gas nozzles 10 is more uniform, thus ensuring that the space and air flow conditions around each gas nozzle 10 are basically the same. After being ignited by the ignition device, a stable flame surface is formed, and the air flow adheres to this flame surface and continues to burn, avoiding local overheating or overcooling. Each gas nozzle 10 can form a more stable flame, realizing a shorter flame and uniform combustion, so that the combustion temperature field distribution is uniform, the evaporation gas can be fully burned, and thus the overall combustion efficiency of the burner is improved. Optionally, the nozzle flow rate is 120 - 180 m / s.

[0060] Refer to Figures 1 to 4 , the combustion device further includes a swirler 20. The swirler 20 is used to make the air flowing out from above it swirl around the center. Among them, at least part of the gas nozzles 10 are located above the swirler 20. When the gas nozzles 10 burn, they are mixed with the surrounding rotating air flow, so that the flame generates swirl, forming a shorter swirling flame during the combustion process, making the flame temperature field distribution uniform and improving the combustion effect. At the same time, since the subsequent air is further mixed with the flue gas, the temperature of the flue gas is reduced, thus reducing the outlet smoke temperature of the burner and meeting the safety requirements.

[0061] Refer to Figure 2, the number of gas nozzles 10 located on the outside in the radial direction is greater than the number of gas nozzles 10 located on the inside in the radial direction. The combustion chamber 60 is often cylindrical or similar in shape, and its diameter gradually increases from the central axis to the outside. In order to make full use of the space of the combustion chamber 60 and optimize the combustion process, the number and distribution of the gas nozzles 10 in this solution are set according to the shape and size of the combustion chamber 60, and the number of gas nozzles 10 in the outer circle is set to be more, so that the combustion conditions of each gas nozzle 10 are more consistent, the heat load distribution in the combustion chamber 60 is optimized, and the occurrence of local overheating or overcooling is prevented.

[0062] In some embodiments of the present invention, the number of the outermost gas nozzles 10 in the radial direction is equal to the number of the blades 21 of the swirler 20. As mentioned above, the gas nozzles 10 are arranged in a divergent manner, and the gas nozzles 10 will have a certain interference with the blades 21 (for example, passing through the blades 21). Therefore, it brings certain challenges to the manufacture of the blades 21 of the swirler 20.

[0063] The number of the outermost gas nozzles 10 is equal to the number of the blades 21 of the swirler 20, and the manufacturing process of the blades 21 is simplified to a certain extent under the premise of ensuring a relatively reasonable spacing. Due to the divergent arrangement of the gas nozzles 10, although the shapes of each blade 21 are different due to the interference of the gas nozzles 10, there is still a certain consistency. For example, the radial outer end of each blade 10 is opened at the same position to make it compatible with the outermost gas nozzle 10, thereby reducing the production cost to a certain extent.

[0064] The combustion device provided by this solution has a simple structure, low equipment cost and simple on-site installation.

[0065] In some embodiments of the present invention, the number of gas nozzles 10 located on the outer side of the adjacent groups in the radial direction is twice the number of gas nozzles 10 located on the inner side in the radial direction. That is, the number of gas nozzles 10 in the inner circle is halved, and while the central angle corresponding to two adjacent gas nozzles 10 in the circumferential direction is greater than zero, the gas nozzles 10 are further uniformly distributed by limiting the number.

[0066] like Figure 2 The combustion device shown in the figure exemplarily shows the arrangement of the gas nozzles 10. The burner claimed in the present invention is not limited to the arrangement shown in the figure.

[0067] like Figure 1As shown, the gas nozzle 10 provided in the above embodiment penetrates from below the swirler 20 to above the swirler 20. Optionally, the gas nozzle 10 passes through the vanes 21 of the swirler 20. The gas ejected from the gas nozzle 10 can directly meet and mix with the air flowing out from above the swirler 20, improving the mixing efficiency and making the combustion more complete.

[0068] In an embodiment not shown in the figure, the gas nozzle 10 is located above the swirler 20, that is, the gas nozzle 10 does not pass through the vanes 21 of the swirler 20. With such a setting, the setting of the swirler 20 is relatively simple, and the gas nozzle 10 does not affect the shape of the swirler 20.

[0069] Refer to Figure 4 , the installation inclination angle of the vanes 21 of the swirler 20 is 30° to 60°. In this embodiment, the installation inclination angle is the angle between the vane 21 and the horizontal. Within this inclination angle range, the fluid can form a relatively stable rotational flow field, reducing the disturbance during the combustion of the burner.

[0070] In some embodiments of the present utility model, the gas nozzle 10 adopts a premixed nozzle, and the ratio of the premixed spray holes to the non-premixed spray holes of the premixed nozzle is 1:1. The setting of the premixed nozzle enables the evaporation gas and air to be preliminarily mixed before entering the combustion chamber 60, so that the combustion can generate a more stable flame. The mixing method of the premixed spray holes and the non-premixed spray holes combines the uniformity of premixed combustion and the diffusivity of non-premixed combustion, which helps to improve the overall mixing efficiency.

[0071] Refer to Figure 1 and Figure 3 , the combustion device further includes a gas main pipe 30 and a gas branch pipe 40. The gas branch pipe is connected between the gas main pipe 30 and the gas nozzle 10. The gas main pipe 30 is used to connect to the evaporation gas outlet end of the liquefied natural gas storage device. Through the branched transportation method, the evaporation gas in the gas main pipe 30 is distributed to a plurality of gas branch pipes 40 and then further supplied to each gas nozzle 10. The combustion device according to this embodiment can balance the gas flow of each nozzle, avoiding the gas flow of a single nozzle being too large or too small, thus affecting the stability and efficiency of combustion.

[0072] Generally, the flow control of the gas nozzle 10 is controlled by the opening cross-sectional area on each gas nozzle 10. Therefore, according to the number of gas nozzles 10 connected to the gas branch pipe 40 and the target flow rate, the pipe diameter of the gas branch pipe 40 can be determined. In the present utility model, by adjusting the pipe diameter, the gas flow of each gas nozzle 10 can be simply controlled, ensuring that the fuel is fully utilized and reducing energy waste. Exemplarily, when the number of gas nozzles 10 connected to the gas branch pipe 40 is large, the pipe diameter of the gas branch pipe 40 is large.

[0073] Optionally, the same group of gas nozzles 10 is connected to the same gas branch pipe 40. By connecting the same group of gas nozzles 10 to the same gas branch pipe 40, it can be ensured that the gas flow received by this group of nozzles is consistent, and at the same time, the number of pipes and connection points can be reduced, thereby simplifying the structure of the entire combustion system. Due to the uniform distribution of the gas flow, the flame in the combustion chamber 60 is more stable and not easily disturbed by external factors (such as wind speed, temperature fluctuations, etc.).

[0074] Optionally, one gas branch pipe 40 corresponds to one group or multiple groups of gas nozzles 10. Each gas branch pipe 40 is responsible for supplying gas to one group or multiple groups of gas nozzles 10. By adjusting the flow distribution of the branch pipe, it can be ensured that each nozzle obtains stable and appropriate gas during the combustion process, thereby improving the stability and efficiency of combustion. At the same time, the number of pipes and connection points is further reduced, thereby simplifying the system structure and reducing the manufacturing cost and maintenance difficulty.

[0075] In some embodiments of the present utility model, the gas branch pipe 40 includes a connecting pipe 41 and a distributing pipe 42. The connecting pipe 41 is communicated with the gas main pipe 30. At least part of the connecting pipe 41 is arranged in the horizontal direction, and at least part of the connecting pipe 41 extends in the height direction.

[0076] The gas nozzle 10 is communicated with the distributing pipe 42. At least part of the distributing pipe 42 is configured as an annular structure, and the distributing pipe 42 is arranged circumferentially around the center. The distributing pipe 42 configured as an annular structure can form an efficient gas distribution network. The annular structure helps to balance the gas pressure in each part, reduce the flow fluctuation caused by the pressure difference, and ensure that each nozzle can obtain a stable and appropriate gas supply, thereby improving the efficiency of the entire combustion system.

[0077] Optionally, two adjacent groups of gas nozzles 10 are connected to the same gas branch pipe 40. Through this embodiment, the gas distribution of these two groups of nozzles is closer, which helps to reduce the uneven gas flow caused by the distance difference. At the same time, the number of pipes and connection points can be reduced, simplifying the layout of the system and the pipeline routing, and reducing the complexity and manufacturing cost of the system.

[0078] As can be seen from the foregoing, the gas nozzles 10 are provided with multiple circles. Correspondingly, the gas branch pipes 40 are provided with multiple circles. In the present utility model, the number of gas nozzles 10 in the outer circle is greater than the number of gas nozzles 10 in the inner circle. Correspondingly, the pipe diameter of the gas branch pipe 40 located in the outer circle is greater than the pipe diameter of the gas branch pipe 40 located in the inner circle.

[0079] In some embodiments of the present utility model, the main gas pipe 30 extends to the swirler 20, and the main gas pipe 30 is fixedly connected to the swirler 20. The main gas pipe 30 provides a fixed position for the swirler 20. Optionally, the highest end of the part of the main gas pipe 30 through which air flows is higher than the connection part of the main gas pipe 30 and the gas branch pipe 40.

[0080] Referring to Figure 5 , the combustion device further includes a housing 50, and the housing 50 covers the outside of the swirler 20 and the gas nozzle 10. The housing 50 is provided with an air inlet 51 for air to flow in, and the air inlet 51 is located at the side and / or bottom of the housing 50, which can ensure that air can smoothly enter the inside of the housing 50 for heat exchange. Through the layout of the air inlet 51 on the housing 50, it is beneficial to form an effective cooling air flow path and improve the cooling efficiency. Optionally, the air flow rate is 10 - 15 m / s.

[0081] Optionally, a plurality of air inlets 51 are arranged in a circumferential array at the side and / or bottom of the housing 50. As Figure 5 shown, the air inlet 51 is arranged at the side of the housing 50. As Figure 6 shown, the air inlet 51 is arranged at the bottom of the housing 50.

[0082] Referring to Figures 6 - 7 , the combustion device further includes a combustion chamber 60, and at least part of the gas nozzles 10 extend from the bottom of the combustion chamber 60 to the inside of the combustion chamber 60. Optionally, the housing 50 is provided with a flange, and the housing 50 is connected to the combustion chamber through the flange.

[0083] The combustion chamber 60 is provided with a cooling air inlet 61 for cooling air to enter. Optionally, the cooling air inlets 61 are arranged in a circumferential array at the side of the combustion chamber 60. The outlet end of the gas nozzle 10 forms a swirling flame, and the swirling flame entrains air in the combustion chamber 60 for cooling, improving the combustion efficiency, making the combustion temperature uniform, and ensuring that the outlet temperature meets the requirements.

[0084] The combustion device provided by this solution is suitable for incinerating the boil-off gas of a liquefied natural gas carrier, and the processing capacity of the boil-off gas is 3600 - 4400 kg / h.

[0085] Unless otherwise defined, the technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field of the present utility model. The terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the present utility model. Terms such as "arranged" as used herein can either mean that one component is directly attached to another component or that one component is attached to another component through an intermediate member. The features described in one embodiment herein can be applied to another embodiment alone or in combination with other features, unless the feature is not applicable or otherwise stated in that other embodiment.

[0086] The present utility model has been described through the above embodiments. However, it should be understood that the above embodiments are only for the purpose of exemplification and illustration, and are not intended to limit the present utility model within the scope of the described embodiments. Those skilled in the art can understand that according to the teachings of the present utility model, more variations and modifications can be made, and these variations and modifications all fall within the scope of protection required by the present utility model.

Claims

1. A combustion device for a liquefied natural gas carrier, characterized in that: The combustion device comprises at least two groups of gas nozzles, each group of gas nozzles being arranged at intervals in the circumferential direction around a central axis, different groups of gas nozzles having different distances from the central axis, and on a plane perpendicular to the central axis, a central angle corresponding to two adjacent gas nozzles in the circumferential direction is greater than zero.

2. The combustion device according to claim 1, characterized in that: The number of the gas nozzles located on the outer side in the radial direction is greater than the number of the gas nozzles located on the inner side in the radial direction.

3. The combustion device according to claim 2, characterized in that: The number of the gas nozzles located on the outer side in the radial direction of the adjacent groups is twice the number of the gas nozzles located on the inner side in the radial direction.

4. The combustion device according to any one of claims 1 to 3, characterized in that: The combustion device further comprises a swirler, which is used to swirl the air flowing out from above the swirler around the center; At least part of the gas nozzles are located above the swirler.

5. The combustion device according to claim 4, characterized in that: The gas nozzle penetrates from the bottom of the swirler to the top of the swirler, or The gas nozzle is located above the swirler.

6. The combustion device according to claim 4, characterized in that: The number of the gas nozzles located at the outermost sides in the radial direction is equal to the number of the blades of the swirler.

7. The combustion device according to claim 4, characterized in that: The installation angle of the blades of the cyclone is 30° to 60°; and / or The gas nozzle is a premixing nozzle, and the ratio of the premixing nozzle holes to the non-premixing nozzle holes is 1:

1.

8. The combustion device according to claim 1, characterized in that: The combustion device also includes: Gas mains; A gas branch pipe, the gas branch pipe is connected between the gas main pipe and the gas nozzle; wherein, The same group of gas nozzles are connected to the same gas branch pipe; and / or One gas branch pipe corresponds to one or more groups of gas nozzles.

9. The combustion device according to claim 8, characterized in that: The gas branch pipe comprises: A connecting pipe, the connecting pipe being in communication with the gas main pipe; A distribution pipe, the gas nozzle is connected to the distribution pipe, at least a portion of the distribution pipe is constructed as an annular structure, and the distribution pipe is arranged circumferentially around the center.

10. The combustion device according to claim 8 or 9, characterized in that: The gas nozzles of two adjacent groups are connected to the same gas branch pipe.

11. The combustion device according to claim 8 or 9, characterized in that: The diameter of the gas branch pipe located in the outer circle is larger than the diameter of the gas branch pipe located in the inner circle.

12. The combustion device according to claim 1, characterized in that: The combustion device further comprises a shell, wherein the shell cover is arranged outside the gas nozzle and the swirler, and the shell is provided with an air inlet for air to flow in, and the air inlet is located at the side and / or bottom of the shell.

13. The combustion device according to claim 1 or 12, characterized in that: The combustion device further includes a combustion chamber, and at least a portion of the gas nozzles extend from the bottom of the combustion chamber to the interior of the combustion chamber.

14. The combustion device according to claim 13, characterized in that: The combustion chamber is provided with a cooling air inlet for cooling air to enter.

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