Submerged combustion type gasification device
By designing water baths and cofferdams in the immersion combustion gasification device, the overflow holes are used to realize the internal and external water circulation, the poor energy saving effect and pollutant emission problems under low load conditions are solved, and the effect of efficient combustion and low heat loss of smoke exhaust is achieved.
Patent Information
- Application Number
- CN202421770711.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-24
- Publication Date
- 2025-06-13
- Estimated Expiration
- 2034-07-24
AI Technical Summary
The existing immersion combustion gasification devices have poor energy saving effect under low load conditions. Excessive air coefficient leads to large heat loss in exhaust smoke, and pollutant emissions do not meet environmental protection requirements.
An immersion combustion gasification device including a water bath and a cofferdam is designed to realize internal and external water circulation through overflow holes, and the low-temperature heat exchange fluid absorbs combustion heat, reduces the flue gas temperature, and heat exchange is carried out through the gas-liquid heat exchange chamber to reduce pollutant emissions.
Under low load conditions, heat recovery is achieved through internal and external water circulation, which reduces heat loss in smoke exhaust, reduces pollutant emissions, ensures the energy-saving effect of the equipment, and makes combustion emissions meet environmental protection requirements.
Smart Images
Figure CN222977899U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of liquefied natural gas, and particularly to a submerged combustion gasification device. Background Art
[0002] The submerged combustion gasification device is a key part in the process of the LNG (liquefied natural gas) receiving terminal in the LNG (liquefied natural gas) industry system. By burning fuel gas, the heat released is transferred to the low-temperature LNG (liquefied natural gas), and after being heated to the target temperature, it is output through the gas supply pipeline network.
[0003] Currently, in order to generate an overflow under low-load conditions in the submerged combustion gasification device and form a water circulation inside and outside the cofferdam, it is necessary to increase the air volume of the fan and increase the volume flow rate of the combustion-supporting air. This will cause the excess air coefficient in the combustion process to be too high, greatly increasing the heat loss of the flue gas and resulting in poor energy-saving effects of the equipment. And due to the excessive excess air coefficient, deviating from the optimal combustion state, it will cause the emissions of flue gas pollutants such as carbon monoxide and nitrogen oxides not to meet the environmental protection requirements. Summary of the Utility Model
[0004] The present application provides a submerged combustion gasification device to solve the technical problem of poor energy-saving effect of the existing submerged combustion gasification device under low-load conditions.
[0005] The present application provides a submerged combustion gasification device, including:
[0006] A water bath;
[0007] A cofferdam, arranged in the water bath. The cofferdam has a heat exchange cavity with one side open. The cofferdam is communicated with the water bath, and both the cofferdam and the water bath are used for arranging a heat exchange liquid;
[0008] A flue gas distribution assembly, at least partially arranged outside the cofferdam. The flue gas distribution assembly is communicated with the heat exchange cavity and is used for introducing high-temperature flue gas into the heat exchange cavity;
[0009] A heat exchange assembly, at least partially arranged in the heat exchange cavity; the heat exchange assembly is configured to allow liquefied natural gas to enter and exit the heat exchange cavity, and the high-temperature flue gas in the heat exchange cavity exchanges heat with the liquefied natural gas in the heat exchange assembly through the heat exchange liquid;
[0010] Wherein, an overflow hole is formed on the cofferdam. The overflow hole is configured to communicate the heat exchange cavity with the water bath, and the overflow hole has a lowest height h 1 , before the high-temperature flue gas exchanges heat with the liquefied natural gas, the heat exchange liquid in the heat exchange cavity and the water bath has the same liquid level height h 2 , the lowest height h 1 and the liquid level height h 2 satisfy: h 1 ≤h 2 .
[0011] As an alternative embodiment of this solution, one side edge of the cofferdam near the opening is an overflow edge, and the overflow edge is configured to allow the heat exchange liquid to overflow from the overflow edge into the water bath as the liquid level in the cofferdam rises.
[0012] As an alternative embodiment of this solution, a plurality of overflow holes are provided. At the same height, the total area A of all the overflow holes i satisfies the following formula:
[0013]
[0014] where Q i is the total flow rate of the overflow holes at the same height, k is a correction coefficient, g is the acceleration due to gravity, and h in is the liquid level height in the cofferdam under low-load heat exchange conditions, is the height of the overflow hole, i = 1, 2, 3, ……, N, and N is the maximum number of rows of the overflow holes.
[0015] As an alternative embodiment of this solution, under low-load heat exchange conditions, the liquid level height h in the cofferdam in satisfies the following formula:
[0016] h in = ρ l ·h out / ρ in ;
[0017] where ρ l is the density of the heat exchange liquid, h out is the liquid level height in the water bath, and ρ in is the gas-liquid mixture density inside the cofferdam.
[0018] As an alternative embodiment of this solution, the gas-liquid mixture density ρ inside the cofferdam in satisfies the following formula:
[0019] ρ in = (ρ gas ·Q gas ·t + ρ l ·(V - Q gas ·t)) / V;
[0020] where ρ gas is the density of the high-temperature flue gas, Q gas is the exhaust gas volume of the high-temperature flue gas, t is the residence time of the high-temperature flue gas in the cofferdam, and V is the internal volume of the cofferdam.
[0021] As one of the optional embodiments of this solution, multiple rows of overflow holes are provided on the cofferdam. Each row of overflow holes includes multiple overflow holes. The total area A of the multiple rows of overflow holes satisfies the following formula: A = ∑A i .
[0022] As one of the optional embodiments of this solution, the flue gas distribution assembly includes a distribution pipe and branch pipes. The distribution pipe is arranged outside the cofferdam, and the branch pipes are connected to the distribution pipe. The branch pipes are arranged on one side of the heat exchange cavity far away from the opening. Air outlet holes are formed in the branch pipes, and the air outlet holes are configured to allow high-temperature flue gas to enter the heat exchange cavity for gas-liquid heat exchange.
[0023] As one of the optional embodiments of this solution, the heat exchange assembly includes a liquid inlet pipe, an air outlet pipe, and heat exchange coils. The liquid inlet pipe is arranged at one end of the heat exchange coils, and the air outlet pipe is arranged at the other end of the heat exchange coils. At least part of the heat exchange coils is immersed in the heat exchange liquid in the heat exchange cavity; the liquid inlet pipe is configured to allow liquefied natural gas to enter the heat exchange coils, and the air outlet pipe is configured to allow the heated natural gas to be discharged from the heat exchange coils; the liquid inlet pipe is arranged on one side far away from the opening relative to the air outlet pipe.
[0024] As one of the optional embodiments of this solution, multiple heat exchange coils are provided, and each heat exchange coil is connected to the liquid inlet pipe and the air outlet pipe.
[0025] As one of the optional embodiments of this solution, the shape of the overflow holes includes at least one of a circle, an ellipse, a rectangle, an equilateral triangle, an inverted triangle, or a long rectangular shape.
[0026] One of the above technical solutions has the following advantages or beneficial effects:
[0027] When the submerged combustion gasification device is under low-load conditions, high-temperature flue gas enters the cofferdam, and gas-liquid heat exchange occurs inside the cofferdam. The mixing of gas and liquid phases causes the mixed density inside the cofferdam to decrease and the liquid level to rise. At this time, the heat exchange liquid overflows through the overflow holes and enters the water bath pool, forming a cycle of the liquid inside and outside the cofferdam. Since the lowest height of the overflow holes is the same as the liquid level height when the submerged combustion gasification device is not operating, when the submerged combustion gasification device is under low-load conditions and the liquid level rises, the heat exchange liquid can flow out from the overflow holes to achieve internal and external circulation.
[0028] Through the internal and external water circulation, the low-temperature heat exchange liquid absorbs part of the heat generated by combustion to reduce the flue gas temperature. This can cause the water vapor generated during the combustion process to condense inside the burner, thereby effectively recovering heat and reducing pollutant emissions in the flue gas. Under low-load conditions, a low excess air coefficient can be selected to maintain efficient combustion, resulting in a smaller flue gas discharge volume. It can also ensure that the upstream burner maintains a stable and reasonable air-fuel ratio, ensuring that combustion emissions such as carbon monoxide and nitrogen oxides are maintained within the environmental protection requirements, with small flue gas heat losses, and thus ensuring the energy-saving effect of the submerged combustion gasification device. Brief Description of the Drawings
[0029] The technical solutions and other beneficial effects of the present application will become apparent by describing the specific embodiments of the present application in detail with reference to the accompanying drawings.
[0030] Figure 1 is a schematic diagram of the overall structure of an immersion combustion gasification device provided by an embodiment of the present application;
[0031] Figure 2 is a side view of an immersion combustion gasification device provided by an embodiment of the present application;
[0032] Figure 3 is an internal sectional view of an immersion combustion gasification device provided by an embodiment of the present application;
[0033] Figure 4 is a schematic diagram of a cofferdam in an immersion combustion gasification device provided by an embodiment of the present application;
[0034] Figure 5 is a partial enlarged view of an immersion combustion gasification device provided by an embodiment of the present application.
[0035] Reference Numerals:
[0036] 1, water bath; 10, cofferdam; 11, opening; 12, heat exchange chamber; 13, overflow hole; 14, overflow edge; 20, flue gas distribution assembly; 210, distribution pipe; 220, branch pipe; 230, air outlet; 30, heat exchange assembly; 310, liquid inlet pipe; 320, gas outlet pipe; 330, heat exchange coil. Detailed Description of the Embodiments
[0037] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present application without creative efforts shall fall within the protection scope of the present application.
[0038] In the description of the present application, it should be noted that unless otherwise clearly defined and limited, the term "and / or" herein is only a description of the associated relationship of the associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " herein generally represents an "or" relationship between the associated objects before and after without special explanation.
[0039] The submerged combustion gasification device is a key part of the process of the LNG (liquefied natural gas) receiving terminal in the LNG (liquefied natural gas) industrial system. By burning fuel gas, the heat released is transferred to the low-temperature LNG, and after heating it to the target temperature, it is output through the gas supply pipeline network.
[0040] Currently, in order to generate an overflow under low-load conditions in the submerged combustion gasification device and form a water circulation inside and outside the cofferdam, it is necessary to increase the air volume of the fan and the volumetric flow rate of the combustion-supporting air. This will cause the excess air coefficient in the combustion process to be too high, greatly increasing the heat loss of the flue gas and resulting in poor energy-saving effects of the equipment. Moreover, due to the excessive excess air coefficient, deviating from the optimal combustion state, it will cause the emissions of flue gas pollutants such as carbon monoxide and nitrogen oxides not to meet the environmental protection requirements.
[0041] Therefore, the present application provides a submerged combustion gasification device. The submerged combustion gasification device provided by the present application can generate an overflow under low-load conditions, form a water circulation inside and outside the cofferdam 10, and will not cause the excess air coefficient in the combustion process to be too high, which helps to reduce the heat loss of the flue gas and ensure the energy-saving effect of the equipment. The submerged combustion gasification device provided by the present application will be described below.
[0042] Specifically, referring to Figure 1 and Figure 2 , the submerged combustion gasification device provided by the present application includes a water bath 1 and a cofferdam 10. The cofferdam 10 is arranged inside the water bath 1. The cofferdam 10 has a heat exchange chamber 12 with an opening 11 on one side. Another side of the cofferdam 10 is provided with a water passing port, and the water passing port is arranged opposite to the opening 11. The opening 11 is opened at the top of the cofferdam 10, and the water passing port is opened at the bottom of the cofferdam 10. The cofferdam 10 is connected to the water bath 1 through the water passing port. Both the cofferdam 10 and the water bath 1 are used for arranging heat exchange liquid. It can be understood that before the submerged combustion gasification device operates, the liquid levels of the heat exchange liquid in the cofferdam 10 and the water bath 1 are the same.
[0043] Referring to Figure 2 and Figure 3 , the submerged combustion gasification device further includes a flue gas distribution component 20 and a heat exchange component 30. At least part of the flue gas distribution component 20 is arranged outside the cofferdam 10. The flue gas distribution component 20 is communicated with the heat exchange chamber 12. The flue gas distribution component 20 introduces high-temperature flue gas into the heat exchange chamber 12 to achieve gas-liquid two-phase heat exchange, that is, the high-temperature flue gas transfers heat to the heat exchange liquid to heat up the heat exchange liquid. At least part of the heat exchange component 30 is arranged inside the heat exchange chamber 12. The heat exchange component 30 is configured to supply liquefied natural gas to enter and exit the heat exchange chamber 12. The high-temperature flue gas in the heat exchange chamber 12 exchanges heat with the liquefied natural gas in the heat exchange component 30 through the heat exchange liquid, that is, the heated heat exchange liquid transfers heat to the liquefied natural gas in the heat exchange component 30, and the liquefied natural gas is heated and then discharged from the heat exchange component 30.
[0044] Refer to Figures 2 to 5 , an overflow hole 13 is provided on the cofferdam 10, and the overflow hole 13 is configured to communicate the heat exchange chamber 12 with the water bath 1. The overflow hole 13 has a minimum height h 1 , before the high-temperature flue gas exchanges heat with the liquefied natural gas, the heat exchange liquid in the heat exchange chamber 12 and the water bath 1 has the same liquid level height h 2 , the minimum height h 1 and the liquid level height h 2 satisfy: h 1 ≤ h 2 .
[0045] When the submerged combustion gasification device is under low-load conditions, a low excess air coefficient can be selected to maintain efficient combustion, thereby generating a small amount of flue gas. The high-temperature flue gas enters the cofferdam 10, and gas-liquid heat exchange occurs inside the cofferdam 10. The mixing of gas and liquid phases causes the mixing density inside the cofferdam 10 to decrease, and the liquid level rises. At this time, the heat exchange liquid overflows through the overflow hole 13 and enters the water bath 1, forming a cycle of the liquid inside and outside the cofferdam 10. Since the minimum height of the overflow hole 13 is the same as the liquid level height when the submerged combustion gasification device is not operating, when the submerged combustion gasification device is under low-load conditions and the liquid level rises, the heat exchange liquid can flow out from the overflow hole 13 to achieve internal and external circulation. Thus, through the internal and external water circulation, the low-temperature heat exchange liquid absorbs part of the heat generated by combustion to reduce the flue gas temperature. This can cause the water vapor generated during the combustion process to condense inside the burner, thereby effectively recovering heat and reducing pollutant emissions in the flue gas. It can also ensure that the upstream burner maintains a stable and reasonable air-fuel ratio, ensuring that combustion emissions such as carbon monoxide and nitrogen oxides are maintained within the environmental protection requirements, and the heat loss of the flue gas is small.
[0046] Further, refer to Figure 3 and Figure 4 , one side edge of the cofferdam 10 close to the opening 11 is an overflow edge 14. When the submerged combustion gasification device is under high-load conditions, the liquid level inside the cofferdam 10 rises, and the heat exchange liquid overflows from both the overflow hole 13 and the overflow edge 14 to the water bath 1 at the same time. When the liquid level height in the water bath 1 is higher than the liquid level height inside the cofferdam 10, the heat exchange liquid in the water bath 1 enters the cofferdam 10 through the water passing hole at the bottom of the cofferdam 10 to maintain the balance of the internal and external liquid level heights.
[0047] Specifically, a plurality of overflow holes 13 are provided on the cofferdam 10. At the same height, the total area A i of all the overflow holes 13 satisfies the following formula:
[0048]
[0049] Wherein, Q i is the total flow rate of the overflow holes 13 at the same height, Q iis a preset value, k is a correction coefficient, g is the acceleration due to gravity, and h in is the liquid level height in the cofferdam 10 under the low-load heat exchange state, is the height of the overflow hole 13, i = 1, 2, 3, ……, N, and N is the maximum number of rows of the overflow holes 13. It is not difficult to understand that the number of rows of the overflow holes 13 can be one row or multiple rows, which is not limited here.
[0050] Furthermore, according to the known liquid level height calculation formula: h = v / s, where v is the liquid volume and s is the cross-sectional area of the container, the liquid level height h in the cofferdam 10 under the low-load working condition is obtained in satisfies the following formula:
[0051] h in = ρ l ·h out / ρ in ;
[0052] Among them, ρ l is the density of the heat exchange liquid. In this embodiment, the heat exchange liquid is water, and ρ l is the density of water; h out is the liquid level height in the water bath 1. When the submerged combustion gasification device is debugged and completed, h out is a fixed value, and ρ in is the gas-liquid mixture density inside the cofferdam 10. It can be understood that the calculation method of the gas-liquid mixture density is the total gas-liquid mixture mass / total volume, and the mass of the high-temperature flue gas and the heat exchange liquid is obtained according to the known formula m = ρ·v, so as to obtain the gas-liquid mixture density ρ inside the cofferdam 10 in satisfies the following formula:
[0053] ρ in = (ρ gas ·Q gas ·t + ρ l ·(V - Q gas ·t)) / V;
[0054] Among them, ρ gas is the density of the high-temperature flue gas, Q gas is the exhaust gas volume of the high-temperature flue gas, t is the residence time of the high-temperature flue gas in the cofferdam 10, and V is the internal volume of the cofferdam. Specifically, the exhaust gas volume Q of the high-temperature flue gas gas is determined by the power of the burner. The residence time t of the high-temperature flue gas in the cofferdam 10 is the time from when the high-temperature flue gas enters the heat exchange liquid to when it leaves the heat exchange liquid; the internal volume V of the cofferdam 10 is the volume of the cofferdam 10 itself minus the volume of the heat exchange component 30 in the cofferdam 10.
[0055] In some embodiments, multiple rows of overflow holes 13 are formed in the cofferdam 10, each row including a plurality of overflow holes 13, and the total area A of the multiple rows of overflow holes 13 satisfies the following formula: A = ∑A i .
[0056] Through the above calculation formula, key parameters such as the position height and quantity size of the required overflow holes 13 can be obtained according to the initial sizes and operating parameters of different cofferdams 10, providing a design basis for the long-term accurate and stable operation of the burner and heat exchanger system, and ensuring high efficiency, energy conservation, and low pollutant emissions.
[0057] It can be understood that the shape of the overflow holes 13 can be any one or a combination of multiple of circular, oval, rectangular, equilateral triangle, inverted triangle, or long rectangular, which is not limited herein. When the overflow holes 13 are circular, the lowest height h1 of the above-mentioned overflow holes 13 is the distance from the bottom end of the cofferdam 10 support to the center of the circle. When the overflow holes 13 are of other shapes, the lowest height h of the overflow holes 13 1 is the distance from the bottom end of the cofferdam 10 support to the geometric center.
[0058] In some embodiments, referring to Figures 1 to 3 , the flue gas distribution assembly 20 includes a distribution pipe 210 and branch pipes 220. The distribution pipe 210 is arranged outside the cofferdam 10, the branch pipes 220 are communicated with the distribution pipe 210, the branch pipes 220 are arranged on one side of the heat exchange chamber 12 far away from the opening 11, and air outlet openings 230 are formed in the branch pipes 220. The air outlet openings 230 are configured to allow high-temperature flue gas to enter the heat exchange chamber 12 for gas-liquid heat exchange.
[0059] The high-temperature flue gas after combustion enters the branch pipes 220 from the distribution pipe 210, and then enters the heat exchange liquid through the air outlet openings 230 on the branch pipes 220. Since the density of the high-temperature flue gas is less than the density of the heat exchange liquid, and the branch pipes 220 are arranged on one side of the heat exchange chamber 12 far away from the opening 11, after the high-temperature flue gas enters the heat exchange liquid, it can bubble upward, and the high-temperature flue gas fully performs two-phase heat exchange with the heat exchange liquid in the heat exchange chamber 12 to heat up the heat exchange liquid.
[0060] In some embodiments, referring to Figures 1 to 3 , the heat exchange assembly 30 includes a liquid inlet pipe 310, a gas outlet pipe 320, and a heat exchange coil 330. The liquid inlet pipe 310 is arranged at one end of the heat exchange coil 330, the gas outlet pipe 320 is arranged at the other end of the heat exchange coil 330, at least part of the heat exchange coil 330 is immersed in the heat exchange liquid in the heat exchange chamber 12, the liquid inlet pipe 310 is configured to supply liquefied natural gas into the heat exchange coil 330, and the gas outlet pipe 320 is configured to discharge the heated natural gas from the heat exchange coil 330; the liquid inlet pipe 310 is arranged on one side far away from the opening 11 relative to the gas outlet pipe 320.
[0061] It is not difficult to understand that in this embodiment, multiple heat exchange coils 330 are provided and are arranged in an S shape within the cofferdam 10. Each heat exchange coil 330 is connected to the liquid inlet pipe 310 and the gas outlet pipe 320. By arranging multiple heat exchange coils 330 within the cofferdam 10 and the heat exchange coils 330 being arranged in an S shape, the residence time of the liquefied natural gas within the heat exchange coils 330 can be ensured, guaranteeing the temperature increase effect of the liquefied natural gas within the cofferdam 10.
[0062] The liquefied natural gas enters the heat exchange coils 330 within the cofferdam 10 from the liquid inlet pipe 310. After the heat exchange liquid within the cofferdam 10 is heated, it transfers heat to the liquefied natural gas within the heat exchange coils 330, causing the liquefied natural gas to be heated and discharged from the gas outlet pipe 320. Since the liquid inlet pipe 310 is arranged on the side far from the opening 11 relative to the liquid outlet pipe, the liquefied natural gas enters the heat exchange coils 330 within the cofferdam 10 from the bottom. After the liquefied natural gas is heated, it is discharged from the gas outlet pipe 320. Thus, a good temperature increase effect of the liquefied natural gas within the heat exchange coils 330 can be ensured.
[0063] It can be understood that when the submerged combustion gasification device is under high load conditions, the heat exchange coils 330 are completely submerged in the heat exchange liquid, and the heat exchange area of the heat exchange coils 330 reaches the maximum. The design of the cross - liquid - level overflow hole 13 of the cofferdam 10 enables the burner to maintain a stable and reasonable air - fuel ratio within the full load range, achieving lower heat loss from flue gas and lower pollutant emissions.
[0064] For the submerged combustion gasification device provided in this application, through calculation formulas, key parameters such as the position height and quantity size of the required overflow holes 13 can be obtained based on different initial sizes and operating parameters of the cofferdam 10, providing a design basis for the long - term accurate and stable operation of the burner and heat exchanger system, and ensuring high efficiency, energy conservation, and low pollutant emissions. In addition, when the submerged combustion gasification device is not operating, the lowest height of the overflow hole is the same as the liquid level height. When the submerged combustion gasification device is under low load conditions, the liquid level rises, and the heat exchange liquid can flow out from the overflow hole, realizing internal and external circulation. Through the internal and external water circulation, the low - temperature heat exchange liquid absorbs part of the heat generated by combustion, reducing the flue gas temperature. This can cause the water vapor generated during the combustion process to condense inside the burner, effectively recovering heat and reducing pollutant emissions in the flue gas. Under low load conditions, a low excess air coefficient can be selected to maintain efficient combustion, thus generating a smaller flue gas volume. It can also ensure that the upstream burner maintains a stable and reasonable air - fuel ratio, ensuring that combustion emissions such as carbon monoxide and nitrogen oxides are maintained within the environmental protection requirements, with small heat loss from flue gas, and thus ensuring the energy - saving effect of the submerged combustion gasification device.
[0065] As described above, it is only a partial implementation manner of the embodiments of the present application, and does not impose any formal restrictions on the application. The protection scope of the embodiments of the present application is not limited thereto. Any simple modifications, equivalent changes, and decorations that can be easily thought of by those skilled in the technical field of the present application within the technical scope disclosed by the embodiments of the present application should be covered within the protection scope of the embodiments of the present application.
Claims
1. A submerged combustion gasification device, characterized in that: include: Water baths; A cofferdam (10) is arranged in the water bath, the cofferdam (10) has a heat exchange chamber (12) with an opening (11) on one side, the cofferdam (10) is connected to the water bath, and the cofferdam (10) and the water bath are both used to place a heat exchange fluid; a flue gas distribution component (20), at least partly disposed outside the cofferdam (10), the flue gas distribution component (20) being in communication with the heat exchange chamber (12) and used for passing high-temperature flue gas into the heat exchange chamber (12); A heat exchange component (30) is at least partially disposed in the heat exchange cavity (12); the heat exchange component (30) is configured to allow liquefied natural gas to enter and exit the heat exchange cavity (12), and the high-temperature flue gas in the heat exchange cavity (12) exchanges heat with the liquefied natural gas in the heat exchange component (30) through the heat exchange fluid; The cofferdam (10) is provided with an overflow hole (13), and the overflow hole (13) is configured to connect the heat exchange chamber (12) and the water bath. The overflow hole (13) has a minimum height h1. Before the high-temperature flue gas and the liquefied natural gas perform heat exchange, the heat exchange liquid in the heat exchange chamber (12) and the water bath has the same liquid level h2. The minimum height h1 and the liquid level h2 satisfy: h1≤h2.
2. The submerged combustion gasification device according to claim 1, characterized in that: An edge of the cofferdam (10) close to the opening (11) is an overflow edge (14), and the overflow edge (14) is configured to allow the heat exchange liquid to overflow from the overflow edge (14) into the water bath as the liquid level in the cofferdam (10) rises.
3. The submerged combustion gasification device according to claim 1, characterized in that: The overflow holes (13) are provided in plurality, and at the same height, the total area A of all the overflow holes (13) is i Satisfies the following formula: Among them, Q i is the total flow rate of the overflow hole (13) at the same height, k is the correction coefficient, g is the gravitational acceleration, h in is the liquid level height in the cofferdam (10) under low load heat exchange conditions, is the height of the overflow hole (13), i=1, 2, 3, ..., N, N is the maximum number of rows of the overflow holes (13).
4. The submerged combustion gasification device according to claim 3, characterized in that: Under low load heat exchange conditions, the liquid level in the cofferdam (10) is in Satisfies the following formula: h in =ρ l ·h out / r in ; Among them, ρ l is the density of the heat transfer fluid, h out is the liquid level in the water bath, ρ in is the gas-liquid mixed density inside the cofferdam (10).
5. The submerged combustion gasification device according to claim 4, characterized in that: The gas-liquid mixture density inside the cofferdam (10) is in Satisfies the following formula: ρ in =(ρ gas ·Q gas ·t+ρ l ·(V-Q gas ·t)) / V; Among them, ρ gas is the density of the high temperature flue gas, Q gas is the exhaust volume of the high-temperature flue gas, t is the residence time of the high-temperature flue gas in the cofferdam (10), and V is the internal volume of the cofferdam (10).
6. The submerged combustion gasification device according to claim 5, characterized in that: The cofferdam (10) is provided with a plurality of rows of overflow holes (13), each row of the overflow holes (13) includes a plurality of the overflow holes (13), and the total area A of the plurality of rows of the overflow holes (13) satisfies the following formula: A=∑A i .
7. The submerged combustion gasification device according to claim 1, characterized in that: The flue gas distribution assembly (20) comprises a distribution pipe (210) and a branch pipe (220); the distribution pipe (210) is arranged outside the cofferdam (10); the branch pipe (220) is connected to the distribution pipe (210); the branch pipe (220) is arranged on a side of the heat exchange chamber (12) away from the opening (11); an air outlet (230) is provided on the branch pipe (220); the air outlet (230) is configured to allow the high-temperature flue gas to enter the heat exchange chamber (12) for gas-liquid heat exchange.
8. The submerged combustion gasification device according to claim 1, characterized in that: The heat exchange component (30) comprises a liquid inlet pipe (310), an air outlet pipe (320) and a heat exchange coil (330); the liquid inlet pipe (310) is arranged at one end of the heat exchange coil (330), the air outlet pipe (320) is arranged at the other end of the heat exchange coil (330), and at least a portion of the heat exchange coil (330) is immersed in the heat exchange liquid of the heat exchange cavity (12); the liquid inlet pipe (310) is configured to allow the liquefied natural gas to enter the heat exchange coil (330), and the air outlet pipe (320) is configured to allow the heated natural gas to discharge from the heat exchange coil (330); the liquid inlet pipe (310) is arranged on a side away from the opening (11) relative to the air outlet pipe (320).
9. The submerged combustion gasification device according to claim 8, characterized in that: A plurality of the heat exchange coils (330) are provided, and each of the heat exchange coils (330) is connected to the liquid inlet pipe (310) and the gas outlet pipe (320).
10. The submerged combustion gasification device according to claim 1, characterized in that: The shape of the overflow hole (13) includes at least one of a circle, an ellipse, a rectangle, an equilateral triangle, an inverted triangle or a long rectangle.