Marine exhaust gas boiler
By using a vertical cylindrical shell and a threaded groove heat exchange tube design, combined with upper and lower tube sheets and insulation layers, the problems of easy pipe damage and low heat recovery efficiency in marine boiler exhaust gas recirculation devices have been solved, achieving high efficiency, energy saving and stable operation.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- HENAN SITONG BOILER
- Filing Date
- 2025-07-02
- Publication Date
- 2026-06-19
Smart Images
Figure CN224382237U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of boiler technology, and more specifically, to a marine exhaust gas boiler. Background Technology
[0002] With increasing global focus on environmental protection and energy conservation and emission reduction, the shipbuilding industry faces the dual pressure of reducing energy consumption and emissions. Marine boilers, as a key component of ship propulsion systems, generate large amounts of high-temperature exhaust gas during operation. If this exhaust gas is discharged directly without effective treatment, it will not only result in significant energy waste but also cause serious air pollution. According to relevant research data, ship exhaust gases contain large amounts of pollutants such as nitrogen oxides, sulfur oxides, and particulate matter, posing a significant threat to the marine ecosystem and surrounding air quality. Therefore, developing efficient marine boiler exhaust gas recycling devices has become a crucial issue that the shipbuilding industry urgently needs to address.
[0003] Existing marine boiler exhaust gas recycling devices have revealed numerous problems in practical applications. For example, the "Boiler Exhaust Gas Waste Heat Recycling System" published in CN105889964A enhances heat absorption by designing the inlet pipe in a spiral shape. However, the inlet pipe is placed directly inside the converter housing. During operation, when water or air enters the pipe, it generates a strong impact, causing frequent contact between the pipe and the housing. This not only generates significant noise, interfering with the ship's normal operating environment, but may also damage the outer wall of the pipe after repeated impacts, thus affecting the device's service life and exhaust gas recycling efficiency.
[0004] Furthermore, some traditional exhaust gas recirculation devices lack adequate measures for securing and limiting the exhaust gas pipes. When exhaust gas passes through the pipes at high speed, the impact force of the gas can easily cause the pipes to shake within the recovery device. Prolonged shaking can lead to collisions between the exhaust gas pipes and the inner wall of the recovery tank, causing damage to the pipes and increasing equipment maintenance costs. It can also cause loosening of connections, leading to exhaust gas leaks, reducing exhaust gas recirculation efficiency, and even posing a potential risk to the safe operation of the ship. Simultaneously, some devices have deficiencies in exhaust gas filtration, allowing dust to accumulate on the inner wall of the exhaust gas pipes, affecting the pipes' thermal conductivity and reducing heat recovery efficiency, thus failing to meet the high-efficiency energy-saving requirements of ships. Utility Model Content
[0005] The purpose of this invention is to provide a marine exhaust gas boiler to solve the problem mentioned in the background art: during use, when water or air enters the pipe, it generates a strong impact on the pipe, causing frequent contact between the pipe and the shell. This not only generates significant noise, interfering with the normal operation of the ship, but may also damage the outer wall of the pipe after repeated collisions, thereby affecting the service life of the device and the efficiency of exhaust gas recycling.
[0006] To achieve the above objectives, this utility model provides a marine exhaust gas boiler, including a cylindrical body. The cylindrical body is vertically arranged, and an upper tube sheet and a lower tube sheet are respectively installed at the upper and lower ends. A plurality of heat exchange tubes are installed inside the cylindrical body, and the upper and lower ends of the heat exchange tubes pass through the upper and lower tube sheets. An exhaust gas box is connected to the bottom of the cylindrical body, and an exhaust gas inlet is provided at the bottom of the exhaust gas box. An exhaust gas outlet is provided at the top of the cylindrical body.
[0007] This design features a vertically arranged cylinder that allows the exhaust gas to flow from bottom to top, optimizing the flow field distribution by utilizing the natural upward movement of hot flue gas. The upper and lower tube sheets are fixed with heat exchange tubes to form a closed steam-water space. When the high-temperature exhaust gas passes through the heat exchange tubes, it transfers heat to the boiler water outside the tubes, thus realizing the heat exchange process.
[0008] Preferably, the outer wall of the cylinder is provided with a heat insulation layer.
[0009] This feature involves wrapping the outer wall of the cylinder with a low thermal conductivity material (such as aluminum silicate fiber) to block the heat conduction path.
[0010] Preferably, the top of the cylinder is equipped with a lifting lug, and a manhole is provided on one side of the middle part of the cylinder.
[0011] The lifting lugs are forged and welded to the top of the cylinder to provide a lifting point; the manhole is located in the middle of the cylinder for maintenance and is equipped with a quick-opening flange sealing structure.
[0012] Preferably, a water inlet pipe is connected to the upper part of one side of the cylinder, and a water return pipe is connected to the lower part of the other side of the cylinder.
[0013] This design features an inlet pipe located at the top of the cylinder to form a water curtain-like inlet, and a return pipe that draws water from the lower low-temperature zone, utilizing density differences to establish a natural circulation loop.
[0014] Preferably, the outer wall surface of the heat exchange tube is provided with a threaded groove.
[0015] This feature uses a cold rolling forming process to create continuous spiral protrusions on the outer wall of the heat exchange tube (pitch 5-8mm, groove depth 0.5-1mm).
[0016] Preferably, the surfaces of the upper tube sheet and the lower tube sheet are provided with a plurality of tube sheet holes, and the upper and lower ends of the heat exchange tube are provided with connecting ends, which are locked in the tube sheet holes and sealed by sealing rings.
[0017] This setting uses an interference fit (0.1-0.3mm) between the tube sheet hole and the connection end, and the sealing ring is made of expanded graphite material, with sealing achieved through pre-tightening force.
[0018] Preferably, a cleaning hole is provided on one side of the bottom of the cylinder, and a drain pipe is connected to the middle of the bottom of the cylinder.
[0019] This setting connects the cleaning hole and the drain pipe to the lowest position at the bottom of the cylinder. The diameter of the cleaning hole is ≥80mm, and the drain pipe uses a flange connection to a quick-opening valve.
[0020] Preferably, an inspection port is provided on one side of the outer wall of the exhaust gas chamber, and a drain outlet is provided on one side of the bottom of the exhaust gas chamber.
[0021] The inspection port is located on the side of the exhaust gas chamber and is equipped with a high-temperature resistant observation window; the sewage outlet is tilted downwards to remove smoke and dust particles using the principle of gravity settling.
[0022] Compared with the prior art, the beneficial effects of this utility model are as follows:
[0023] In this marine exhaust gas boiler, the cylinder is vertically arranged and internally fitted with threaded grooved heat exchange tubes, forming a highly efficient heat exchange structure in conjunction with the upper and lower tube sheets. The threaded groove design increases the contact area between the heat exchange tubes and the exhaust gas, enhances the turbulence of the flue gas within the tubes, and significantly improves the heat transfer coefficient. Compared to traditional smooth tube structures, this significantly improves the thermal energy conversion efficiency, allows for more complete absorption of waste heat from the exhaust gas, enhances the ship's energy utilization efficiency, and reduces energy consumption.
[0024] The upper and lower tube sheets are connected to the heat exchange tubes through tube sheet holes and sealed with sealing rings. This connection method ensures a stable connection between the heat exchange tubes and the tube sheet, effectively preventing gas leakage. At the same time, the reasonable structural layout keeps the entire device stable during ship operation, resists the impact force generated by exhaust gas flow, reduces the risk of damage caused by shaking and collision, and extends the service life of the equipment.
[0025] The manhole in the cylinder allows staff to easily enter for inspection, maintenance, and cleaning; the cleaning hole and drain pipe at the bottom can quickly remove accumulated dirt and impurities, preventing them from affecting the heat exchange effect; the inspection port and drain port of the exhaust gas chamber facilitate inspection and cleaning of the inside of the chamber, effectively preventing dust accumulation, reducing maintenance difficulty, costs, and time. Attached Figure Description
[0026] Figure 1This is a schematic diagram of the overall structure of this utility model;
[0027] Figure 2 This is a schematic diagram of the heat exchange tube in this utility model;
[0028] Figure 3 This is a schematic diagram of the upper tube sheet in this utility model;
[0029] The meanings of the labels in the diagram are as follows:
[0030] 1. Shell; 11. Insulation layer; 12. Manhole; 13. Lifting lug; 14. Water inlet pipe; 15. Water return pipe; 16. Scale removal hole; 17. Sewage pipe; 18. Exhaust gas outlet; 2. Heat exchange tube; 21. Threaded groove; 22. Connection end; 221. Sealing ring; 3. Upper tube sheet; 31. Tube sheet hole; 4. Lower tube sheet; 5. Exhaust gas chamber; 51. Exhaust gas inlet; 52. Inspection port; 53. Sewage outlet. Detailed Implementation
[0031] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0032] This utility model provides a marine exhaust gas boiler, such as Figure 1 As shown, the device includes a cylindrical body 1, which is vertically arranged, with an upper tube sheet 3 and a lower tube sheet 4 installed at its upper and lower ends, respectively. Several heat exchange tubes 2 are installed inside the cylindrical body 1, with the upper and lower ends of the heat exchange tubes 2 passing through the upper tube sheet 3 and the lower tube sheet 4. An exhaust gas chamber 5 is connected to the bottom of the cylindrical body 1, with an exhaust gas inlet 51 at the bottom of the exhaust gas chamber 5 and an exhaust gas outlet 18 at the top of the cylindrical body 1.
[0033] The vertically arranged cylinder 1 allows the exhaust gas to flow from bottom to top, optimizing the flow field distribution by utilizing the natural upward movement of hot flue gas. Several heat exchange tubes 2 are fixed to the upper tube sheet 3 and lower tube sheet 4 at both ends, forming a closed steam-water space. High-temperature exhaust gas enters through the exhaust gas inlet 51 at the bottom of the exhaust gas chamber 5, transferring heat to the boiler water outside the tubes as it passes through the heat exchange tubes 2, and finally exits through the exhaust gas outlet 18 at the top of the cylinder 1, thus completing the heat exchange process. Compared to a horizontal structure, the vertical cylinder 1 design reduces the floor space required, adapting to space constraints on ships; the counter-current heat exchange method increases the logarithmic mean temperature difference, enhancing heat transfer efficiency; the exhaust gas chamber 5, acting as a gas collection chamber, reduces local resistance and ensures that the flue gas enters each heat exchange tube 2 uniformly.
[0034] In this embodiment, as Figure 1 As shown, the outer wall of the cylinder 1 is provided with a heat insulation layer 11.
[0035] The insulation layer 11 on the outer wall of the cylinder 1 is made of a low thermal conductivity material such as aluminum silicate fiber, which blocks the heat conduction path. According to tests, this can reduce heat loss from the boiler surface by 10%-15%, thereby improving energy efficiency; it also avoids the risk of burns caused by accidental contact with the high-temperature surface of the cylinder 1, thus improving safety.
[0036] Specifically, such as Figure 1 As shown, a lifting lug 13 is installed on the top of the cylinder 1, and a manhole 12 is provided on one side of the middle part of the cylinder 1.
[0037] The lifting lug 13 installed on the top of the cylinder 1 is welded to the cylinder 1 by forging process, providing a lifting force point; the manhole 12 set on one side of the middle of the cylinder 1 is equipped with a quick-opening flange sealing structure.
[0038] The lifting lug 13 helps maintain the center of gravity balance when the boiler is hoisted as a whole, simplifying the installation process; the manhole 12 has a diameter of ≥450mm, which meets the needs of maintenance personnel to enter and exit, and facilitates the inspection and replacement of components such as heat exchange tubes 2 inside the shell 1.
[0039] Furthermore, such as Figure 1 As shown, a water inlet pipe 14 is connected to the upper part of one side of the cylinder 1, and a water return pipe 15 is connected to the lower part of the other side of the cylinder 1.
[0040] The water inlet pipe 14 connected to the upper part of one side of the cylinder 1 forms a water curtain-type water inlet, while the water return pipe 15 connected to the lower part of the other side draws water from the low-temperature zone, establishing a natural circulation loop by utilizing the density difference. This improves the steam-water separation efficiency, ensuring that the steam humidity is ≤3% and preventing water hammer. A reasonable water circulation ratio of 4-6 times ensures that the pipe wall is fully cooled, avoiding local overheating and scaling inside the cylinder 1.
[0041] Furthermore, such as Figure 2 As shown, the outer wall surface of the heat exchange tube 2 is provided with a threaded groove 21.
[0042] The threaded grooves 21 on the outer wall surface of the heat exchange tube 2 are formed by cold rolling, creating continuous spiral protrusions with a pitch of 5-8 mm and a groove depth of 0.5-1 mm. When the flue gas flows, a turbulent boundary layer is formed at the threaded grooves 21, increasing the Reynolds number by 20%-30% and enhancing the convective heat transfer coefficient. Under the same conditions, the heat exchange tube 2 with threaded grooves 21 has a heat transfer efficiency that is 40%-60% higher than that of a bare tube, effectively reducing the exhaust gas temperature by about 15-20℃.
[0043] Furthermore, such as Figure 3 As shown, the upper tube sheet 3 and the lower tube sheet 4 are provided with a number of tube sheet holes 31. The upper and lower ends of the heat exchange tube 2 are equipped with connecting ends 22, which are locked in the tube sheet holes 31 and sealed by sealing rings 221.
[0044] The tube sheet holes 31 on the surfaces of the upper tube sheet 3 and the lower tube sheet 4 are connected to the upper and lower ends 22 of the heat exchange tube 2 with an interference fit of 0.1-0.3 mm. The sealing ring 221 inside the connection end 22 is made of expanded graphite material, and the seal is achieved through pre-tightening force. This eliminates the stress concentration problem of expansion or welding connections and adapts to ship vibration conditions. Under high temperature, the sealing ring 221 expands to fill the gap, preventing steam and water leakage. The sealing performance meets the ASME BPVC Section VIIIDiv.1 standard.
[0045] Furthermore, such as Figure 1 As shown, a cleaning hole 16 is provided on one side of the bottom of the cylinder 1, and a drain pipe 17 is connected to the middle of the bottom of the cylinder 1.
[0046] The cleaning hole 16 located on one side of the bottom of the cylinder 1 and the drain pipe 17 connected to the middle of the bottom are located at the lowest position of the bottom of the cylinder 1. The diameter of the cleaning hole 16 is ≥80mm, and the drain pipe 17 is connected to a flanged quick-opening valve. During operation, the valve of the drain pipe 17 can be opened periodically to remove sludge and control the sewage discharge rate to 2%-5% to prevent scale buildup. During maintenance, high-pressure water flushing is performed through the cleaning hole 16 to clean the tube sheet surface and maintain heat exchange efficiency.
[0047] Furthermore, such as Figure 1 As shown, an inspection port 52 is provided on one side of the outer wall of the exhaust gas chamber 5, and a drain port 53 is provided on one side of the bottom of the exhaust gas chamber 5.
[0048] The inspection port 52 on one side of the exhaust gas chamber 5 is equipped with a high-temperature resistant observation window; the drain port 53 on the bottom side is tilted downwards to remove smoke particles by gravity settling.
[0049] During operation, the flue gas flow status can be observed in real time through inspection port 52; the ash can be discharged by regularly opening the drain port 53. According to statistics, this can reduce the flue gas resistance by 25%-30% and prevent the ash from clogging the heat exchange tube 2 and affecting ventilation.
[0050] In operation, the marine exhaust gas boiler of this invention first receives the high-temperature exhaust gas generated by the ship's main engine through a pipeline from the exhaust gas inlet 51 at the bottom of the exhaust gas box 5. The exhaust gas box 5 serves as a gas collection and buffer unit. Utilizing the principle of gravity settling, some larger dust particles accumulate at the bottom of the box and can be periodically discharged through the drain port 53 on one side of the bottom, reducing the impurity content entering the heat exchange tubes 2 and lowering the smoke resistance. Simultaneously, operators can observe the exhaust gas flow and ash accumulation in real time through the inspection port 52 on the outer wall of one side of the box.
[0051] The high-temperature exhaust gas entering the exhaust gas chamber 5 flows upwards, passing through several heat exchange tubes 2 fixed inside the cylinder 1 by the upper tube sheet 3 and the lower tube sheet 4. The threaded grooves 21 on the outer wall of the heat exchange tubes 2 create turbulence within the tubes, enhancing convective heat transfer. The heat from the high-temperature exhaust gas is transferred to the boiler water outside the tubes through the tube walls. The upper and lower tube sheets 3 and 4 are sealed to the heat exchange tubes 2 via interference fits at the tube sheet holes 31 and connecting ends 22, as well as sealing rings 221, ensuring the airtightness of the steam-water space and preventing heat loss and media leakage. After heat exchange, the low-temperature exhaust gas is finally discharged from the exhaust gas outlet 18 at the top of the cylinder 1.
[0052] Simultaneously with heat exchange, the water circulation system operates. Cold water is injected into the upper part of one side of the cylinder 1 through the inlet pipe 14, forming a water curtain-like inlet. The lower part of the other side draws water from the low-temperature zone, establishing a natural circulation loop using density differences. After absorbing heat transferred from the heat exchange tubes 2, the boiler water heats up and vaporizes, generating steam that can be used for ship heating, power, and other systems. This circulation design improves steam-water separation efficiency, ensuring steam humidity is ≤3%, avoiding water hammer, and a reasonable water circulation ratio of 4-6 times ensures sufficient cooling of the pipe walls, preventing localized overheating and scaling inside the cylinder 1.
[0053] To maintain the boiler's long-term stable and efficient operation, the system is equipped with a comprehensive maintenance structure. During operation, the drain pipe 17 in the middle of the bottom of the shell 1 can be opened periodically to discharge the sludge deposited at the bottom at a rate of 2%-5%. During maintenance, high-pressure water flushing is performed through the cleaning hole 16 on one side of the bottom of the shell 1 to clean the dirt on the tube sheet and heat exchange tube surfaces. In addition, the insulation layer 11 on the outer wall of the shell 1 reduces heat loss, the lifting lugs 13 at the top facilitate equipment hoisting and installation, and the manhole 12 on one side of the middle allows maintenance personnel to enter the interior for inspection and component replacement.
[0054] Throughout the entire operation, the waste gas boiler achieves efficient waste heat recovery and utilization by optimizing the waste gas flow path, strengthening the heat exchange structure, and designing a reasonable water circulation system, thereby achieving the goals of energy conservation, emission reduction, and lower ship operating costs.
[0055] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed utility model. The scope of protection of this utility model is defined by the appended claims and their equivalents.
Claims
1. A marine exhaust gas boiler comprising a cylinder (1), characterized in that: The cylinder (1) is vertically arranged, and an upper tube sheet (3) and a lower tube sheet (4) are installed at the upper and lower ends respectively. Several heat exchange tubes (2) are installed inside the cylinder (1). The upper and lower ends of the heat exchange tubes (2) pass through the upper tube sheet (3) and the lower tube sheet (4). The bottom of the cylinder (1) is connected to a waste gas chamber (5). The bottom of the waste gas chamber (5) is provided with a waste gas inlet (51). The top of the cylinder (1) is provided with a waste gas outlet (18).
2. Marine exhaust gas boiler according to claim 1, characterized in that: The outer wall of the cylinder (1) is provided with a heat insulation layer (11).
3. Marine exhaust gas boiler according to claim 1, characterized in that: The top of the cylinder (1) is equipped with a lifting lug (13), and a manhole (12) is provided on one side of the middle part of the cylinder (1).
4. Marine exhaust gas boiler according to claim 1, characterized in that: A water inlet pipe (14) is connected to the upper part of one side of the cylinder (1), and a water return pipe (15) is connected to the lower part of the other side of the cylinder (1).
5. Marine exhaust gas boiler according to claim 1, characterized in that: The outer wall surface of the heat exchange tube (2) is provided with a threaded groove (21).
6. Marine exhaust gas boiler according to claim 1, characterized in that: The upper tube sheet (3) and the lower tube sheet (4) are provided with a number of tube sheet holes (31). The upper and lower ends of the heat exchange tube (2) are equipped with connecting ends (22). The connecting ends (22) are stuck in the tube sheet holes (31) and sealed by sealing rings (221).
7. Marine exhaust gas boiler according to claim 1, characterized in that: A cleaning hole (16) is provided on one side of the bottom of the cylinder (1), and a drain pipe (17) is connected to the middle of the bottom of the cylinder (1).
8. Marine exhaust gas boiler according to claim 1, characterized in that: An inspection port (52) is provided on one side of the outer wall of the exhaust gas chamber (5), and a drain port (53) is provided on one side of the bottom of the exhaust gas chamber (5).