Marine dual-fuel fire-tube boiler

Abstract

The invention discloses a marine dual-fuel fire-tube boiler, and relates to the technical field of marine boilers. The problems that in combustion of an ammonia boiler, needed ignition energy is large, the combustible range is narrow, the laminar flow combustion speed is low, combustion is unstable due to natural nitrogen, and nitrogen oxide emission is high are solved. Boiler feed water enters the feed water heating cabin through the feed water heating water inlet, flows out of the feed water heating water outlet after being heated, enters the water inlet of the evaporation cabin, is heated into saturated steam in the evaporation cabin, enters the steam pipeline through the steam outlet and then is supplied to steam supply equipment. The feed water heating cabin is arranged in the fire-tube boiler, so that the smoke exhaust temperature can be greatly reduced, and the smoke exhaust loss is reduced; according to the device, two fuels of No.0 diesel oil and ammonia gas can be combusted together, the clean energy ammonia gas fuel which is easy to store and low in price can be fully utilized, stable combustion of the ammonia fuel can be guaranteed, the heat value of the fuel can be properly improved, and then the heat exchange efficiency is improved to 90%-95%. The invention is suitable for the field of fire-tube boilers.

Description

Technical Field

[0001] This invention relates to the field of marine boiler technology, specifically to a marine dual-fuel fire-tube boiler. Background Technology

[0002] Currently, marine space is limited, and marine boiler designs strive to minimize size. Fire-tube boilers, due to their simple structure and ease of maintenance, are used as auxiliary boilers in ships. With increasingly stringent requirements for pollutant emissions from ship navigation and mooring in some sea areas and ports, and the implementation of the IMO's carbon reduction strategy, the demand for green and clean fuel marine boilers is becoming increasingly strong. Ammonia fuel is easy to store and inexpensive. Ammonia is one of the most common, readily available, and inexpensive green and clean compounds. Ammonia can be liquefied under normal pressure (approximately 8-10 atmospheres) or at low temperatures (-33.4℃), significantly reducing its volume and facilitating transportation and storage. Liquid ammonia is chemically relatively stable and does not easily spontaneously combust or decompose. Based on these characteristics, ammonia fuel is well-suited for use as fuel for marine auxiliary boilers.

[0003] However, ammonia combustion has problems such as requiring a large ignition energy, having a narrow combustible range, slow laminar combustion speed, and unstable combustion and high nitrogen oxide emissions caused by natural nitrogen content. Summary of the Invention

[0004] This invention addresses the problems of high ignition energy requirements, narrow combustible range, slow laminar combustion speed, combustion instability and high nitrogen oxide emissions caused by natural nitrogen content in ammonia boilers. It proposes a marine dual-fuel fire-tube boiler to improve the stability of ammonia combustion, ensure high-efficiency energy output, improve boiler efficiency, and reduce pollutant emissions.

[0005] The present invention provides a marine dual-fuel fire-tube boiler, which comprises a mixed fuel burner 1, a furnace 2, an evaporation chamber 4, a water level gauge 5, a feedwater heating chamber 7, a flue gas collection area 8, a first baffle 11, a second baffle 14, a threaded flue assembly 15, and a shell 17.

[0006] The inner bottom surface of the shell 17 is provided with a furnace 2, and the lower part of the outer surface of the shell 17 is provided with a mixed fuel burner 1. The output end of the mixed fuel burner 1 is connected to the interior of the furnace 2. The interior of the shell 17 is provided with a first partition 11 and a second partition 14 from top to bottom. The first partition 11 and the second partition 14 divide the interior of the shell 17 into a flue gas collection area 8, a feedwater heating chamber 7 and an evaporation chamber 4. The evaporation chamber 4 is provided with a water level gauge 5, and the display of the water level gauge 5 is located on the outer surface of the shell 17. A threaded smoke pipe assembly 15 is provided in the center of the interior of the shell 17. The threaded smoke pipe assembly 15 passes through and is fixed inside the feedwater heating chamber 7 and the evaporation chamber 4.

[0007] Furthermore, one end of the outer surface of the shell 17 is provided with a steam outlet 6 and a maintenance manhole 3 from top to bottom, and the steam outlet 6 and the maintenance manhole 3 are evenly arranged in correspondence with the evaporation chamber 4 inside the shell 17.

[0008] Furthermore, the top of the housing 17 is provided with a flue gas outlet 10, and the flue gas outlet 10 is connected to the flue gas collection area 8 inside the housing 17.

[0009] Furthermore, the outer surface of the housing 17 is provided with an inspection port 9, and the inspection port 9 is correspondingly provided with the flue gas collection area 8 inside the housing 17.

[0010] Furthermore, the other end of the outer surface of the shell 17 is provided with a water heating outlet 12 and a water heating inlet 13 in sequence along the height direction, and the water heating outlet 12 and the water heating inlet 13 are correspondingly arranged with the water heating chamber 7 inside the shell 17.

[0011] Furthermore, an evaporation chamber inlet 18 is provided at the lower part of the other end of the outer surface of the shell 17;

[0012] Furthermore, the inner shell 16 of the furnace 2 is completely submerged in the water space of the evaporation chamber 4;

[0013] Furthermore, the inner wall of the inner shell 16 of the furnace 2 is used to absorb the radiant heat of the flame combustion and transfer the heat to the interior of the evaporation chamber 4.

[0014] Furthermore, the inner bottom plate of the inner shell 16 of the furnace chamber 2 is made of high-temperature resistant heat insulation material;

[0015] Furthermore, the threaded smoke tube assembly 15 includes heat exchange tubes 19 and support tubes 20; multiple heat exchange tubes 19 are evenly arranged between the first partition 11 inside the shell 17 and the middle of the upper surface of the furnace 2, and the multiple heat exchange tubes 19 are arranged in a circular array. A support tube 20 is provided between every two heat exchange tubes 19. The outer diameter of both the heat exchange tubes 19 and the support tube 20 is 38mm, and the wall thickness of the support tube 20 is 6.5mm, and the wall thickness of the heat exchange tube 19 is 5mm.

[0016] Furthermore, this invention uses both No. 0 diesel and ammonia as fuel. Under the design conditions, the calorific value ratio of ammonia to diesel is 4:1, and the mass ratio is 9.6:1. The fuel ratio can also be adjusted according to specific needs. Boiler feedwater enters the feedwater heating chamber 7 through the feedwater heating inlet 13. After heating, the water flows out from the feedwater heating outlet 12 and enters the evaporation chamber inlet 18 through connecting pipes. In the evaporation chamber 4, the water is heated into saturated steam and enters the steam pipeline through the steam outlet 6, thereby supplying steam to the steam supply equipment. The inner shell 16 of the furnace 2 is completely submerged in the water space of the evaporation chamber 4. Its top and side plates can absorb the radiant heat from the combustion of the flame in the furnace and transfer the heat to the water in the evaporation chamber. Its bottom is made of high-temperature resistant insulation material to prevent heat damage to the bottom plate.

[0017] The flue gas generated by combustion enters the threaded flue assembly 15, where it transfers heat to the water and steam in the evaporation chamber, and also transfers some heat to the water in the feedwater heating chamber 7. After heat transfer, the flue gas passes through the first partition 11 and enters the flue gas collection area 8, finally exiting the boiler through the flue gas outlet 10 and entering the exhaust duct. For convenient boiler maintenance, this invention includes a maintenance manhole 3 and a maintenance port 9. A water level gauge 5 is provided for timely monitoring of the water level during boiler operation.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] This invention overcomes the shortcomings of existing technologies. The fire-tube boiler of this invention has an internal feedwater heating chamber, which can significantly reduce flue gas temperature and minimize flue gas losses. Furthermore, this device can co-burn both No. 0 diesel and ammonia, making full use of easily stored and inexpensive clean energy ammonia fuel. This ensures stable combustion of ammonia fuel while appropriately increasing the fuel's calorific value, thereby improving heat exchange efficiency to 90%-95%. Moreover, this fire-tube boiler has a smaller volume, saving considerable space on ships. Attached Figure Description

[0020] Figure 1 This is a front sectional view of a marine dual-fuel fire-tube boiler according to the present invention.

[0021] Figure 2 This is a side sectional view of a marine dual-fuel fire-tube boiler according to the present invention. Detailed Implementation

[0022] Specific implementation method one: Combining Figure 1 and Figure 2 This embodiment describes a marine dual-fuel fire-tube boiler, which comprises a mixed fuel burner 1, a furnace 2, an evaporation chamber 4, a water level gauge 5, a feedwater heating chamber 7, a flue gas collection area 8, a first baffle 11, a second baffle 14, a threaded smoke tube assembly 15, and a shell 17.

[0023] The inner bottom surface of the shell 17 is provided with a furnace 2, and the lower part of the outer surface of the shell 17 is provided with a mixed fuel burner 1. The output end of the mixed fuel burner 1 is connected to the interior of the furnace 2. The interior of the shell 17 is provided with a first partition 11 and a second partition 14 from top to bottom. The first partition 11 and the second partition 14 divide the interior of the shell 17 into a flue gas collection area 8, a feedwater heating chamber 7 and an evaporation chamber 4. The evaporation chamber 4 is provided with a water level gauge 5, and the display of the water level gauge 5 is located on the outer surface of the shell 17. A threaded smoke pipe assembly 15 is provided in the center of the interior of the shell 17. The threaded smoke pipe assembly 15 passes through and is fixed inside the feedwater heating chamber 7 and the evaporation chamber 4.

[0024] In this specific embodiment, the present invention uses both No. 0 diesel and ammonia as fuel. Under the design conditions, the calorific value ratio of ammonia to diesel is 4:1, and the mass ratio is 9.6:1. The fuel ratio can also be adjusted according to specific needs. Boiler feedwater enters the feedwater heating chamber 7 through the feedwater heating inlet 13. After heating, the water flows out from the feedwater heating outlet 12 and enters the evaporation chamber inlet 18 through connecting pipes. In the evaporation chamber 4, the water is heated into saturated steam and enters the steam pipeline through the steam outlet 6, thereby supplying steam to the steam supply equipment. The inner shell 16 of the furnace 2 is completely submerged in the water space of the evaporation chamber 4. Its top and side plates can absorb the radiant heat from the combustion of the flame in the furnace and transfer the heat to the water in the evaporation chamber. Its bottom is made of high-temperature resistant insulation material to prevent heat damage to the bottom plate.

[0025] The flue gas generated by combustion enters the threaded flue assembly 15, where it transfers heat to the water and steam in the evaporation chamber, and also transfers some heat to the water in the feedwater heating chamber 7. After heat transfer, the flue gas passes through the first partition 11 and enters the flue gas collection area 8, finally exiting the boiler through the flue gas outlet 10 and entering the exhaust duct. For convenient boiler maintenance, this invention includes a maintenance manhole 3 and a maintenance port 9. A water level gauge 5 is provided for timely monitoring of the water level during boiler operation.

[0026] Specific Implementation Method Two: Combining Figure 1 and Figure 2 This embodiment further defines the fire-tube boiler described in Specific Embodiment 1. In this embodiment, a marine dual-fuel fire-tube boiler is provided with a steam outlet 6 and a maintenance manhole 3 from top to bottom on one end of the outer surface of the shell 17, and the steam outlet 6 and the maintenance manhole 3 are evenly distributed in correspondence with the evaporation chamber 4 inside the shell 17.

[0027] Specific implementation method three: Combining Figure 1 and Figure 2This embodiment further defines the fire-tube boiler described in Specific Embodiment Two. In this embodiment, a marine dual-fuel fire-tube boiler is provided with a flue gas outlet 10 at the top of the shell 17, and the flue gas outlet 10 is connected to the flue gas collection area 8 inside the shell 17.

[0028] Specific implementation method four: Combination Figure 1 and Figure 2 This embodiment further defines the fire-tube boiler described in Specific Embodiment 3. In this embodiment, a marine dual-fuel fire-tube boiler is provided with an inspection port 9 on the upper part of the outer surface of the shell 17, and the inspection port 9 is correspondingly provided with the flue gas collection area 8 inside the shell 17.

[0029] Specific Implementation Method Five: Combining Figure 1 and Figure 2 This embodiment further defines the fire-tube boiler described in Specific Embodiment 4. In this embodiment, a marine dual-fuel fire-tube boiler is provided with a feedwater heating outlet 12 and a feedwater heating inlet 13 sequentially along the height direction on the upper part of the other end of the outer surface of the shell 17, and the feedwater heating outlet 12 and the feedwater heating inlet 13 are correspondingly arranged with the feedwater heating chamber 7 inside the shell 17.

[0030] Specific Implementation Method Six: Combination Figure 1 and Figure 2 This embodiment further defines the fire-tube boiler described in Specific Embodiment Five. In this embodiment, a marine dual-fuel fire-tube boiler is provided with an evaporation chamber inlet 18 at the lower part of the other end of the outer surface of the shell 17.

[0031] Specific implementation method seven: Combination Figure 1 and Figure 2 This embodiment further defines the fire-tube boiler described in Specific Embodiment 1. In this embodiment, the inner shell 16 of the furnace 2 is completely submerged in the water space of the evaporation chamber 4.

[0032] Specific implementation method eight: Combination Figure 1 and Figure 2 This embodiment further defines the fire-tube boiler described in Specific Embodiment Seven. In this embodiment, the inner wall of the inner shell 16 of the furnace 2 is used to absorb the radiant heat from the flame combustion and transfer the heat to the interior of the evaporation chamber 4.

[0033] Specific Implementation Method Nine: Combining Figure 1 and Figure 2This embodiment further defines the fire-tube boiler described in Specific Embodiment Eight. In this embodiment, the inner bottom plate of the inner shell 16 of the furnace 2 is made of high-temperature resistant heat-insulating material.

[0034] Specific Implementation Method Ten: Combining Figure 1 and Figure 2 This embodiment further defines the fire-tube boiler described in Specific Embodiment 1. The marine dual-fuel fire-tube boiler described in this embodiment includes a threaded smoke tube assembly 15 comprising heat exchange tubes 19 and support tubes 20. Multiple heat exchange tubes 19 are evenly arranged between the first partition 11 inside the shell 17 and the center of the upper surface of the furnace 2, and these multiple heat exchange tubes 19 are arranged in a circular array. A support tube 20 is provided between every two heat exchange tubes 19. The outer diameter of both the heat exchange tubes 19 and the support tube 20 is 38 mm, and the wall thickness of the support tube 20 is 6.5 mm, while the wall thickness of the heat exchange tubes 19 is 5 mm.

[0035] In this specific embodiment, both the heat exchange tube 19 and the support tube 20 have an outer diameter of 38mm, with the support tube 20 having a wall thickness of 6.5mm and the heat exchange tube 19 having a wall thickness of 5mm. Both types of pipes possess strong heat exchange capabilities, and the support tube 20 also serves to strengthen the overall structure. Both the heat exchange tube 19 and the support tube 20 have threaded sections machined inside, with a thread depth of 1.5mm and a thread pitch of 24mm. The heat exchange tube 19 and the support tube 20 are arranged in a certain proportion, allowing the tube bundle to support the weight of the upper part.

[0036] Working principle

[0037] This invention uses a combination of No. 0 diesel and ammonia for fuel combustion. Under the design conditions, the calorific value ratio of ammonia to diesel is 4:1, and the mass ratio is 9.6:1. The fuel ratio can be adjusted according to specific needs. Boiler feedwater enters the feedwater heating chamber 7 through the feedwater heating inlet 13. After heating, the water flows out from the feedwater heating outlet 12 and enters the evaporation chamber inlet 18 through connecting pipes. In the evaporation chamber 4, the water is heated into saturated steam and enters the steam pipeline through the steam outlet 6, thus supplying steam to the steam supply equipment. The inner shell 16 of the furnace 2 is completely submerged in the water space of the evaporation chamber 4. Its top and side plates can absorb the radiant heat from the combustion flame in the furnace and transfer the heat to the water in the evaporation chamber. Its bottom is made of high-temperature resistant insulation material to prevent heat damage to the bottom plate.

[0038] The flue gas generated by combustion enters the threaded flue assembly 15, where it transfers heat to the water and steam in the evaporation chamber, and also transfers some heat to the water in the feedwater heating chamber 7. After heat transfer, the flue gas passes through the first partition 11 and enters the flue gas collection area 8, finally exiting the boiler through the flue gas outlet 10 and entering the exhaust duct. For convenient boiler maintenance, this invention includes a maintenance manhole 3 and a maintenance port 9. A water level gauge 5 is provided for timely monitoring of the water level during boiler operation.

Claims

1. A marine dual-fuel fire-tube boiler, characterized in that: It includes a mixed fuel burner (1), furnace (2), evaporation chamber (4), water level gauge (5), feedwater heating chamber (7), flue gas collection area (8), first partition (11), second partition (14), threaded flue assembly (15), and shell (17). The inner bottom surface of the shell (17) is provided with a furnace (2), and the lower part of the outer surface of the shell (17) is provided with a mixed fuel burner (1). The output end of the mixed fuel burner (1) is connected to the interior of the furnace (2). The interior of the shell (17) is provided with a first partition (11) and a second partition (14) from top to bottom. The first partition (11) and the second partition (14) divide the interior of the shell (17) into a flue gas collection area (8), a water supply heating chamber (7) and an evaporation chamber (4). The interior of the evaporation chamber (4) is provided with a water level gauge (5), and the display of the water level gauge (5) is located on the outer surface of the shell (17). The center of the interior of the shell (17) is provided with a threaded smoke pipe assembly (15), and the threaded smoke pipe assembly (15) is fixed inside the water supply heating chamber (7) and the evaporation chamber (4).

2. A marine dual-fuel fire-tube boiler according to claim 1, characterized in that: The outer surface of the shell (17) is provided with a steam outlet (6) and a maintenance manhole (3) from top to bottom, and the steam outlet (6) and the maintenance manhole (3) are evenly arranged in the evaporation chamber (4) inside the shell (17).

3. A marine dual-fuel fire-tube boiler according to claim 2, characterized in that: The top of the housing (17) is provided with a flue gas outlet (10), and the flue gas outlet (10) is connected to the flue gas collection area (8) inside the housing (17).

4. A marine dual-fuel fire-tube boiler according to claim 3, characterized in that: The outer surface of the housing (17) is provided with an inspection port (9), and the inspection port (9) is correspondingly provided with the flue gas collection area (8) inside the housing (17).

5. A marine dual-fuel fire-tube boiler according to claim 4, characterized in that: The outer surface of the shell (17) is provided with a water heating outlet (12) and a water heating inlet (13) in sequence along the height direction at the other end of the upper part, and the water heating outlet (12) and the water heating inlet (13) are correspondingly arranged with the water heating chamber (7) inside the shell (17).

6. A marine dual-fuel fire-tube boiler according to claim 5, characterized in that: An evaporation chamber inlet (18) is provided at the lower part of the other end of the outer surface of the shell (17).

7. A marine dual-fuel fire-tube boiler according to claim 1, characterized in that: The inner shell (16) of the furnace (2) is completely submerged in the water space of the evaporation chamber (4).

8. A marine dual-fuel fire-tube boiler according to claim 7, characterized in that: The inner wall of the inner shell (16) of the furnace (2) is used to absorb the radiant heat of the flame combustion and transfer the heat to the interior of the evaporation chamber (4).

9. A marine dual-fuel fire-tube boiler according to claim 8, characterized in that: The inner bottom plate of the inner shell (16) of the furnace (2) is made of high-temperature resistant heat insulation material.

10. A marine dual-fuel fire-tube boiler according to claim 1, characterized in that: The threaded smoke tube assembly (15) includes a heat exchange tube (19) and a support tube (20); multiple heat exchange tubes (19) are evenly arranged between the first partition (11) inside the shell (17) and the middle of the upper surface of the furnace (2), and the multiple heat exchange tubes (19) are arranged in a circular array. A support tube (20) is provided between every two heat exchange tubes (19). The outer diameter of both the heat exchange tube (19) and the support tube (20) is 38mm, and the wall thickness of the support tube (20) is 6.5mm, and the wall thickness of the heat exchange tube (19) is 5mm.

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