Double-walled exhaust pipe for gas combustion unit, and gas combustion unit for LNG carrier
By using a double-walled exhaust pipe design and cooling air between the inner and outer pipes, the high cost and low space utilization caused by the insulation layer in the existing technology are solved, achieving efficient heat dissipation and space optimization.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- HUDONG ZHONGHUA SHIPBUILDINGGROUP
- Filing Date
- 2025-09-17
- Publication Date
- 2026-05-21
AI Technical Summary
Existing gas combustion devices require thick insulation layers to be laid on the exhaust pipes for heat insulation, resulting in high costs, difficult operation, and space occupation on ships, thus reducing space utilization.
It adopts a double-wall exhaust pipe design, with the inner and outer pipes not in direct contact. The inner pipe is equipped with a combustion chamber, and the outer pipe has cooling air inlets on both sides. The cooling air cools the inner pipe wall through the gap ring cavity, avoiding the insulation layer, and the heat dissipation is enhanced by the use of guide fins.
The use of insulation layers was reduced, which lowered costs and operational complexity, and improved the utilization rate of ship space.
Smart Images
Figure CN2025121856_21052026_PF_FP_ABST
Abstract
Description
A double-walled exhaust pipe for a gas combustion device and a gas combustion device for LNG ships. Technical Field
[0001] This invention relates to the field of shipbuilding technology, and in particular to a double-walled exhaust pipe for a gas combustion device and a gas combustion device for LNG ships. Background Technology
[0002] When LNG carriers are navigating with cargo, a large amount of volatile natural gas is generated in the cargo tanks. Natural gas is a greenhouse gas, with a greenhouse effect 40 times that of carbon dioxide, and cannot be directly released into the atmosphere. The Gas Combustion Unit (GCU) is a crucial device for handling the volatile gases from the LNG carrier's cargo tanks. Existing LNG carriers use the GCU to directly combust the volatile natural gas in the cargo tanks, thus preventing its direct release into the atmosphere.
[0003] The high-temperature exhaust gas from the combustion chamber of the gas combustion unit (GCU) is directly discharged into the atmosphere through the exhaust pipe. In order to prevent the high-temperature exhaust pipe from causing damage to surrounding equipment or personnel, a thick layer of insulation needs to be wrapped around the exhaust pipe of the GCU for heat insulation. However, the diameter of the exhaust pipe of the GCU is usually more than three meters and the height is usually more than seven meters. Laying a thick heat insulation layer on the outer wall of the exhaust pipe of the GCU is not only costly and difficult to operate, but also takes up space and reduces the utilization rate of the limited space on the ship. Summary of the Invention
[0004] In view of the deficiencies in the prior art, this application provides a gas combustion device to solve the technical problems caused by laying an insulation layer on the exhaust pipe of the gas combustion device, such as high gas combustion cost, difficulty in laying the insulation layer, and reduced space utilization of the ship.
[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:
[0006] A double-walled exhaust pipe for a gas combustion device includes an inner exhaust pipe and an outer exhaust pipe. The inner exhaust pipe is disposed inside the outer exhaust pipe and is not in direct contact with the outer exhaust pipe. A combustion chamber is disposed inside the inner exhaust pipe. The combustion chamber is provided with a gas inlet, a combustion air inlet, and an exhaust port. Gas enters the combustion chamber through the gas inlet, and combustion air enters the combustion chamber through the combustion air inlet. The exhaust gas generated by the combustion of gas is discharged from the combustion chamber through the exhaust port and enters the inner exhaust pipe. A first cooling air inlet and a second cooling air inlet are respectively disposed on the left and right sides of the outer exhaust pipe.
[0007] In one embodiment, the ends of the inner and outer exhaust pipes are set at the same height, and the first and second cooling air inlets are at the same height.
[0008] In one embodiment, the first cooling air inlet is connected to a first cooling air duct, and the second cooling air inlet is connected to a second cooling air duct. The height of the first cooling air duct is the same as the height of the first cooling air inlet. The pipe axes of the first cooling air duct and the second cooling air duct are parallel to each other and neither passes through the center of the outer pipe of the exhaust pipe.
[0009] In one embodiment, the inner exhaust pipe and the outer exhaust pipe are arranged concentrically, and a bracket is provided between the inner exhaust pipe and the outer exhaust pipe, with one end of the bracket connected to the inner exhaust pipe and the other end of the bracket connected to the outer exhaust pipe.
[0010] In one embodiment, the support is a sliding support.
[0011] In one embodiment, guide ribs are provided on the outer wall of the inner tube of the exhaust pipe.
[0012] In one embodiment, the guide ribs are wound around the outer wall of the inner tube of the exhaust pipe in a spiral upward state.
[0013] This application also provides an LNG marine gas combustion device, including the aforementioned double-walled exhaust pipe.
[0014] Compared with the prior art, this application has at least the following beneficial effects:
[0015] The gas combustion device of this invention uses a double-walled exhaust pipe, which includes an outer exhaust pipe and an inner exhaust pipe disposed inside the outer exhaust pipe. The inner exhaust pipe is provided with a combustion chamber, and the exhaust gas emitted from the combustion chamber is discharged into the atmosphere along the inner exhaust pipe. The left and right sides of the outer exhaust pipe are respectively provided with a first cooling air inlet and a second cooling air inlet. The cooling air enters the annular cavity between the inner and outer exhaust pipes through the first and second cooling air inlets to cool the wall of the inner exhaust pipe. This avoids the need to lay an insulation layer on the outer wall of the exhaust pipe. The diameter of the outer exhaust pipe is smaller than the diameter of the exhaust pipe with an insulation layer in the prior art. Therefore, this application improves the space utilization rate of ships. Attached Figure Description
[0016] Figure 1 is a cross-sectional view of a double-walled exhaust pipe for a gas combustion device in an embodiment of this application;
[0017] Figure 2 is a top view of a double-walled exhaust pipe for a gas combustion device according to an embodiment of this application.
[0018] Reference numerals: 1. Double-walled exhaust pipe for gas combustion device; 2. Inner pipe of exhaust pipe; 3. Outer pipe of exhaust pipe; 4. Guide rib; 5. Combustion chamber; 6. Support; 7. First cooling air inlet; 71. First cooling air duct; 8. Second cooling air inlet; 81. Second cooling air duct; 9. Combustion air inlet; 10. Gas inlet; 11. Exhaust port. Detailed Implementation
[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is described below with reference to specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.
[0020] The terminology used in this disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. The singular forms “a,” “the,” and “the” as used in this disclosure and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.
[0021] It should be understood that although the terms first, second, third, etc., may be used in this disclosure to describe various information, such information should not be limited to these terms and should not be construed as indicating or implying relative importance. These terms are used only to distinguish information of the same type from one another. For example, without departing from the scope of this disclosure, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to determination."
[0022] In the description of this invention, unless otherwise specified and limited, it should be noted that the terms "installation", "connection" and "linking" should be interpreted broadly. For example, they can refer to mechanical connection or internal connection between two components. They can be direct connection or indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.
[0023] To better understand the technical solution of the present invention, the present invention will be described in detail below with reference to the accompanying drawings.
[0024] As shown in Figures 1 and 2, this application provides a double-walled exhaust pipe 1 for a gas combustion device, including an inner exhaust pipe 2 and an outer exhaust pipe 3. The inner exhaust pipe 2 is disposed inside the outer exhaust pipe 3, and the inner exhaust pipe 2 and the outer exhaust pipe 3 are not in direct contact. A combustion chamber 5 is disposed inside the inner exhaust pipe 2. The combustion chamber 5 is provided with a gas inlet 10, a combustion air inlet 9, and an exhaust port 11. Gas enters the combustion chamber 5 through the gas inlet 10, and combustion air enters the combustion chamber 5 through the combustion air inlet 9. The exhaust gas generated by combustion is discharged from the combustion chamber 5 through the exhaust port 11 and enters the inner exhaust pipe 2. A first cooling air inlet 7 and a second cooling air inlet 8 are respectively disposed on the left and right sides of the outer exhaust pipe 3. Cooling air enters the annular cavity between the inner exhaust pipe 2 and the outer exhaust pipe 3 through the first cooling air inlet 7 and the second cooling air inlet 8, respectively, to cool the pipe wall of the inner exhaust pipe 2.
[0025] The ends of the inner tube 2 and the outer tube 3 of the exhaust pipe are set at the same height. The first cooling air inlet 7 and the second cooling air inlet 8 are at the same height. The first cooling air inlet 7 is connected to the first cooling air duct 71, and the second cooling air inlet 8 is connected to the second cooling air duct 81. The height of the first cooling air duct 71 is the same as the height of the first cooling air inlet 7. The tube axis of the first cooling air duct 71 and the tube axis of the second cooling air duct 81 are parallel to each other and neither passes through the center of the outer tube 3 of the exhaust pipe, thereby increasing the disturbance of the cold air in the spacer cavity and accelerating the heat dissipation of the inner tube 2 of the exhaust pipe.
[0026] The inner exhaust pipe 2 and the outer exhaust pipe 3 are concentrically arranged. A support 6 is installed between the inner exhaust pipe 2 and the outer exhaust pipe 3. One end of the support 6 is connected to the inner exhaust pipe 2, and the other end of the support 6 is connected to the outer exhaust pipe 3 to support the inner exhaust pipe 2. Both the inner exhaust pipe 2 and the outer exhaust pipe 3 will undergo thermal expansion, resulting in a temperature difference between them. Consequently, there will be a significant temperature difference between the inner exhaust pipe 2 and the outer exhaust pipe 3, causing a certain degree of axial displacement. To ensure the supporting effect of the support 6 on the inner exhaust pipe 2, the support 6 is a sliding support.
[0027] The outer wall of the inner tube 2 of the exhaust pipe is provided with guide ribs 4, which are spirally wound around the outer wall of the inner tube 2. The spirally rising guide ribs 4 are used to guide the cooling air and form a stable upward vortex cooling airflow, which is beneficial to the heat dissipation of the inner tube 2 of the exhaust pipe.
[0028] The working principle of the double-walled exhaust pipe 1 in the gas combustion device of this application is as follows:
[0029] The combustion gas enters the combustion chamber 5 through the combustion gas inlet 10, and the combustion air enters the combustion chamber 5 through the combustion air inlet 9. The combustion gas and combustion air are burned in the combustion chamber 5. The high-temperature exhaust gas generated by combustion is discharged into the inner tube 2 of the exhaust pipe through the exhaust port. The inner tube 2 of the exhaust pipe exchanges heat with the high-temperature exhaust gas, and the inner tube 2 of the exhaust pipe becomes high temperature. The cooling air enters the spacer cavity between the inner tube 2 of the exhaust pipe and the outer tube 3 of the exhaust pipe through the first cooling air inlet 7 and the second cooling air inlet 8 respectively. The cold air flows upward along the guide ribs 4 on the outer wall of the inner tube 2 of the exhaust pipe, which enhances the heat convection heat exchange between the inner tube 2 of the exhaust pipe and the outer tube 3 of the exhaust pipe. The combustion waste and the cooling air are discharged into the outside atmosphere together at the ends of the first cooling air inlet 7 and the second cooling air inlet 8.
[0030] This embodiment also provides an LNG marine gas combustion device, including the aforementioned double-walled exhaust pipe.
[0031] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of the invention or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the technical solutions claimed in the present invention.
Claims
1. A double-walled exhaust pipe for a gas combustion device, characterized by, It includes an inner exhaust pipe and an outer exhaust pipe. The inner exhaust pipe is installed inside the outer exhaust pipe and is not in direct contact with the outer exhaust pipe. The inner exhaust pipe has a combustion chamber inside, which has a gas inlet, a combustion air inlet and an exhaust port. Gas enters the combustion chamber through the gas inlet and combustion air enters the combustion chamber through the combustion air inlet. The exhaust gas produced by the combustion of gas is discharged from the combustion chamber through the exhaust port and enters the inner exhaust pipe. The outer exhaust pipe has a first cooling air inlet and a second cooling air inlet on its left and right sides, respectively.
2. The double wall exhaust pipe according to claim 1, characterized by The ends of the inner and outer pipes of the exhaust pipe are set at the same height, and the first and second cooling air inlets are at the same height.
3. The double wall exhaust pipe according to claim 2, wherein The first cooling air inlet is connected to the first cooling air duct, and the second cooling air inlet is connected to the second cooling air duct. The height of the first cooling air duct is the same as the height of the first cooling air inlet. The pipe axes of the first cooling air duct and the second cooling air duct are parallel to each other and neither passes through the center of the outer pipe of the exhaust pipe.
4. The double wall exhaust pipe according to claim 1, wherein The inner and outer exhaust pipes are concentrically arranged, and a support is provided between the inner and outer exhaust pipes. One end of the support is connected to the inner exhaust pipe, and the other end of the support is connected to the outer exhaust pipe.
5. The double wall exhaust pipe according to claim 4, wherein The bracket is a sliding bracket.
6. The double wall exhaust pipe according to claim 1, wherein The outer wall of the inner tube of the exhaust pipe is equipped with guide ribs.
7. The double wall exhaust pipe according to claim 6, wherein The guide ribs are spirally wound around the outer wall of the inner tube of the exhaust pipe.
8. A gas burning device for LNG carriers, characterized by Includes the double-walled exhaust pipe as described in any one of claims 1-7.