Micro-combustion steam generator and steam generation method

Abstract

The present application is to solve the problem of low steam dryness and high energy consumption in the existing steam generating device; a micro hearth steam generating device and steam generating method are provided, wherein the generating device comprises a steam-water separator, an air chamber and a combustion chamber; the combustion chamber is arranged in communication with the air chamber; the combustion chamber is further provided with a first heating structure, which is used for flowing through the water flow; the steam-water separator is connected with the first heating structure and is used for separating liquid water and high-temperature steam; an energy saver is further included, the energy saver is provided with a second heating structure, the second heating structure is connected with one end of the first heating structure away from the steam-water separator; the cavity inside the energy saver is further communicated with the combustion chamber; a chimney for discharging flue gas is further arranged on the energy saver; the water flow direction and the flue gas flow direction are opposite, so that the water flow can be fully heated to form superheated steam.

Description

Technical Field

[0001] This invention relates to the field of steam generator technology, and in particular to a micro furnace steam generator and steam generation method. Background Technology

[0002] A steam generator is a device that uses external energy to heat water and convert it into steam, typically natural gas. As an alternative to traditional boilers, steam generators offer advantages such as smaller size, faster steam production, and simpler installation / use procedures, as illustrated in patents CN212481237U and CN105066657B. However, due to unreasonable structural designs in existing steam generators, such as the furnace and heating surfaces, many products on the market suffer from low steam dryness and high energy consumption. Some products even have a water volume exceeding 30L, which not only fails to meet the new boiler regulations' exemption from inspection but also poses significant safety hazards. Therefore, a steam generator with high volumetric heat load, high heat transfer efficiency, and small water volume is needed. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a micro furnace steam generator and a steam generation method.

[0004] To solve the above problems, the present invention adopts the following technical solution:

[0005] A micro furnace steam generator includes a steam-water separator, a ventilation chamber, and a combustion chamber. The combustion chamber is connected to the ventilation chamber, allowing combustible gas introduced into the ventilation chamber to enter the combustion chamber for combustion. A first heating structure is also provided within the combustion chamber, through which water flows. The steam-water separator is connected to the first heating structure and is used to separate liquid water and high-temperature steam. The generator also includes an energy-saving device, which contains a second heating structure connected to the end of the first heating structure furthest from the steam-water separator. The internal cavity of the energy-saving device is also connected to the combustion chamber, allowing high-temperature flue gas to pass sequentially through the combustion chamber and the energy-saving device. A chimney is also provided on the energy-saving device for discharging the flue gas.

[0006] The ventilation chamber includes a gas inlet, a combustion air inlet, a mixing chamber, and a cooling structure; the mixing chamber is a hollow tubular structure; one end of the mixing chamber is connected to the combustion chamber, and the other end of the mixing chamber is provided with a combustion air inlet; a gas inlet is also provided on the side of the mixing chamber; a cooling structure to prevent heat backflow is also provided between the mixing chamber and the combustion chamber; the cooling structure is also connected to a second heating structure, so that the cooling heat-absorbing liquid flows into the second heating structure for heating.

[0007] Furthermore, a hot water tank and a water pump are provided between the second heating structure and the first heating structure; the hot water tank is used to store the liquid heated by the second heating structure; the water pump is located between the hot water tank and the first heating structure.

[0008] Furthermore, the cooling structure includes a cooling water manifold and a labyrinthine distribution of water-cooled pipes; the cooling water manifold includes an inlet manifold and an outlet manifold respectively located at both ends of the water-cooled pipe structure; the water-cooled pipe structure is located between the mixing chamber and the combustion chamber.

[0009] Furthermore, the water-cooled pipe structure includes several parallel water-cooled pipes arranged at equal intervals; the cross-section of the water-cooled pipes is Z-shaped, and different water-cooled pipes are located on the same horizontal plane.

[0010] Furthermore, the side of the water-cooled pipe closest to the combustion chamber is also provided with a high emissivity coating.

[0011] Furthermore, a flow-dividing structure is provided between the mixing chamber and the cooling structure; the flow-dividing structure includes a funnel-shaped flow-dividing shell and flow-dividing plates; wherein the side with the larger opening in the flow-dividing shell is connected to the cooling structure, and the side with the smaller opening is connected to the mixing chamber; several flow-dividing plates are provided between the flow-dividing shells.

[0012] Furthermore, the first heating structure includes a radiant heating zone and a convection heating surface; the combustion chamber is provided with a radiant heating zone and a convection heating surface from top to bottom; wherein the radiant heating zone is the part of gas combustion; the radiant heating zone is connected to the convection heating surface; the convection heating surface includes a number of finned tubes, two rows of finned tubes form a group, and the convection heating surface includes 3 to 4 groups of finned tubes; the finned tubes in the same row of finned tubes are distributed from top to bottom, the upstream and downstream spacing of adjacent finned tubes is 80 mm, and the spacing of adjacent finned tubes in the same group of finned tubes is 50 mm.

[0013] Furthermore, the finned tube has an H-shaped cross-section; the finned tube thickness is 2mm, and the spacing between adjacent fins in the finned tube is 4mm.

[0014] A steam generation method, based on the above-described steam generation apparatus, includes the following steps:

[0015] Step 1: Water flows into the water-cooling pipe structure, absorbs heat in the water-cooling pipe, and then enters the second heating structure;

[0016] Step 2: The cooled flue gas around the second heating structure heats the water flow in the second heating structure, and then the water flow heated to 60℃~70℃ enters the hot water tank;

[0017] Step 3: The water pump delivers water from the hot water tank to the first heating structure. The water flows through the convection heating surface and the periphery of the radiation heating area of ​​the first heating structure, and finally forms water vapor which is transported outward.

[0018] The beneficial effects of this invention are as follows:

[0019] By setting up a first heating structure and a second heating structure, the water flow direction is opposite to the flue gas flow direction, allowing the water to be fully heated and forming superheated steam.

[0020] By setting up a cooling structure, on the one hand, the problem of backfire is avoided and safety is improved; on the other hand, in conjunction with a high emissivity coating, the water flow is initially heated, improving heat transfer efficiency.

[0021] By setting up a radiant heating zone in conjunction with a convective heating surface, the flames and high-temperature flue gas generated by combustion in the radiant heating zone can directly scour the convective heating surface. Combined with the high-density finned tubes in the convective heating surface, the dryness of the steam is greatly improved under the premise of low water volume. Attached Figure Description

[0022] Figure 1 This is a structural connection block diagram of Example 1;

[0023] Figure 2 This is a schematic diagram of the overall structure of Example 1;

[0024] Figure 3 This is a schematic diagram of the ventilation chamber in Example 1;

[0025] Figure 4 This is a cross-sectional view of the ventilation chamber in Example 1;

[0026] Figure 5 This is a schematic diagram of the first heating structure and the steam-water separator in Example 1;

[0027] Attached diagram labels: 1 Ventilation chamber, 2 Radiant heating zone, 3 Steam-water distribution pipe, 4 Convection heating surface, 5 Steam-water separator, 6 Eco-friendly device, 7 Chimney, 1-1 Gas inlet, 1-2 Combustion air inlet, 1-3 Mixing chamber, 1-4 Baffle plate, 1-5 Cooling water header, 1-6 Water-cooled pipe structure, 1-7 High emissivity coating, 1-51 Inlet header, 1-52 Outlet header, 1-53 Cooling water inlet and outlet, 2-1 Steam header, 4-1 Finned tube. Detailed Implementation

[0028] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features described therein can be combined with each other.

[0029] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Therefore, the figures only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex. Example

[0030] A micro furnace steam generator includes a steam-water separator 5, a ventilation chamber 1, and a combustion chamber. The combustion chamber is connected to the ventilation chamber 1, allowing combustible gas introduced into the ventilation chamber 1 to enter the combustion chamber for combustion. A first heating structure is also provided within the combustion chamber, through which water flows. The water flowing through the first heating structure comes into contact with the high-temperature flue gas generated after combustion in the combustion chamber, absorbing heat and causing the water to heat up and generate a large amount of steam. The steam-water separator 5 is connected to the first heating structure and is used to separate the steam after it has passed through the first heating structure. The system includes liquid water and high-temperature steam; it also includes an energy-saving device 6, which has a second heating structure connected to the end of the first heating structure away from the steam-water separator 5; the cavity inside the energy-saving device 6 is also connected to the combustion chamber, so that the high-temperature flue gas can pass through the combustion chamber and the energy-saving device 6 in sequence, wherein the temperature of the flue gas entering the energy-saving device 6 is approximately between 200°C and 250°C, and after heat exchange through the second heating structure, the temperature of the flue gas that finally flows out is approximately between 50°C and 70°C; the energy-saving device 6 is also equipped with a chimney 7 for discharging flue gas.

[0031] The ventilation chamber 1 includes a gas inlet 1-1, a combustion air inlet 1-2, a mixing chamber 1-3, and a cooling structure. The mixing chamber 1-3 is a hollow tubular structure. One end of the mixing chamber 1-3 is connected to the combustion chamber, and the other end of the mixing chamber 1-3 is provided with a combustion air inlet 1-2. The combustion air inlet 1-2 is also equipped with a fan to help external air flow into the mixing chamber 1-3. A gas inlet 1-1 is also provided on the side of the mixing chamber 1-3. A cooling structure to prevent heat backflow is provided between the mixing chamber 1-3 and the combustion chamber. The cooling structure is also connected to a second heating structure, so that the cooled and heat-absorbing liquid flows into the second heating structure for further heating. The cooling structure includes a cooling water manifold 1-5 and a labyrinthine water-cooled pipe structure 1-6. In this example, the cooling water manifold 1-5 includes an inlet manifold 1-51 and an outlet manifold 1-52 located at both ends of the water-cooled pipe structure 1-6. Multiple cooling water inlets and outlets 1-53 are provided at both the inlet manifold 1-51 and the outlet manifold 1-52, allowing water to enter the inlet manifold 1-51 and exit the outlet manifold 1-52 in multiple streams. The water-cooled pipe structure 1-6 is located between the mixing chamber 1-3 and the combustion chamber. The water-cooled pipe structure 1-6 includes several parallel water-cooled pipes arranged at equal intervals. In this example, the cross-section of the water-cooled pipes is Z-shaped, and different water-cooled pipes are located on the same horizontal plane. A high emissivity coating 1-7 is also provided on the side of the water-cooled pipe near the combustion chamber to help the water-cooled pipe absorb the heat that escapes from the combustion chamber to the water-cooled pipe area, so as to prevent this heat from affecting the gas in the ventilation chamber 1, and also to prevent the flame backflow of combustion in the combustion chamber, thus improving safety. In this example, the thickness of the high emissivity coating 1-7 is 50μm~80μm and the emissivity is 0.9.

[0032] A flow-dividing structure is also provided between the mixing chamber 1-3 and the cooling structure. The flow-dividing structure includes a funnel-shaped outer shell and flow-dividing plates. The side with the larger opening of the outer shell connects to the cooling structure, and the side with the smaller opening connects to the mixing chamber 1-3. Several flow-dividing plates are arranged between the outer shells. It should be noted that in this example, the mixing chamber 1-3 is horizontally positioned above the combustion chamber, while the flow-dividing structure is vertical. Therefore, a 90° bend is provided between the mixing chamber 1-3 and the flow-dividing structure for connection. Through the flow-dividing structure, the gas mixed in the mixing chamber 1-3 flows evenly into the combustion chamber.

[0033] A hot water tank and a water pump are also provided between the second heating structure and the first heating structure; the hot water tank is used to store the liquid after it has been preliminarily heated by the second heating structure; the water pump is located between the hot water tank and the first heating structure and is used to pump the liquid in the hot water tank into the first heating structure. The hot water tank and the water pump are located outside the combustion chamber and the economizer 6.

[0034] The first heating structure includes a radiant heating zone 2 and a convection heating surface 4; wherein the radiant heating zone 2 and the convection heating surface 4 are arranged sequentially from top to bottom in the combustion chamber, with the radiant heating zone 2 located close to the cooling structure; the radiant heating zone 2 is the main part for gas combustion heat exchange; the radiant heating zone 2 is connected to the convection heating surface 4; the convection heating surface 4 includes several finned tubes 4-1, with two rows of finned tubes 4-1 forming a group, and the convection heating surface 4 includes 3 to 4 groups of finned tubes 4-1; the finned tubes 4-1 in the same row are distributed from top to bottom, with an upstream-downstream spacing of 80 mm between adjacent finned tubes 4-1, and an adjacent spacing of 50 mm between adjacent finned tubes 4-1 in the same group. The cross-section of the finned tube 4-1 is H-shaped; the thickness of the finned tube 4-1 is 2 mm, and the spacing between adjacent fins in the finned tube 4-1 is 4 mm. Each row of finned tubes 4-1 is equipped with a thermocouple at its outlet to detect the tube wall temperature. It should be noted that the thermocouple is used to detect the tube wall temperature exiting the finned tubes 4-1. In this example, if the tube wall temperature exceeds the set range, it needs to be adjusted in conjunction with the water pump to achieve a relatively stable liquid temperature flowing through the finned tubes 4-1. It should also be noted that in this example, the high-temperature flue gas directly impacts the radiant heating zone and convective heating surface within the combustion chamber, resulting in a large contact area between the flue gas and the steam header on the sides of the finned tubes or radiant heating zone 2. This allows the water flow within to be fully heated and rapidly converted into steam.

[0035] The radiant heating zone 2 includes a rectangular furnace and steam headers 2-1 distributed around the furnace. In this example, the furnace height is 100mm~200mm. The furnace is constructed entirely of high-strength corundum refractory castable, with a thickness of 100mm. In this example, a steam-water separator 5 is positioned between the steam headers 2-1 around the radiant heating zone 2 and the convective heating surface 4. A steam-water distribution pipe 3 is also provided between the steam-water separator 5 and the convective heating surface 4. The steam-water distribution pipe 3 includes multiple inlets, each corresponding to multiple sets of finned tubes 4-1, and an outlet connected to the steam-water separator 5. The use of a relatively low furnace reduces the residence time of flue gas in the furnace, allowing the combustion flame to directly impact the convective heating surface 4 below the furnace. The convective heating surface 4 absorbs the heat contained in the flame and flue gas, thus heating the water flowing between the convective heating surfaces 4.

[0036] The bottom of the combustion chamber is connected to the top of the energy-saving device 6. The energy-saving device 6 is also equipped with a baffle plate with a gap between the baffle plate and the bottom side of the energy-saving device 6 for flue gas to circulate. The connection between the combustion chamber and the energy-saving device 6 and the chimney 7 inside the energy-saving device 6 are located on both sides of the baffle plate, so that the flue gas entering the energy-saving device 6 can flow a longer distance, fully exchange heat with the second heating structure inside the energy-saving device 6, and then flow out from the chimney 7.

[0037] According to actual measurements, the total water storage capacity of the cooling structure, the first heating structure, the second heating structure, and the hot water tank in this example is 25.2L, and the actual water vapor evaporation rate is 1t / h.

[0038] A steam generation method, based on the above-described steam generation apparatus, includes the following steps:

[0039] Step 1: Water flows into the water-cooling pipe structure 1-6, absorbs heat in the water-cooling pipe, and then enters the second heating structure;

[0040] Step 2: The cooled flue gas around the second heating structure heats the water flow in the second heating structure, and then the water flow heated to 60℃~70℃ enters the hot water tank;

[0041] Step 3: The water pump sends the water from the hot water tank to the first heating structure. The water flows through the convection heating surface 4 and the periphery of the radiation heating zone 2 of the first heating structure, and finally forms water vapor which is transported outward.

[0042] During implementation, by setting up a first heating structure and a second heating structure, the water flow direction and the flue gas flow direction are opposite, allowing the water to be fully heated to form superheated steam. By setting up a radiant heating zone 2 in conjunction with a convective heating surface 4, the flame and high-temperature flue gas generated by combustion in the radiant heating zone 2 can directly scour the convective heating surface 4. Combined with the high-density finned tubes 4-1 in the convective heating surface 4, the dryness of the steam is greatly improved under the premise of low water volume. By setting up water-cooled pipe structures 1-6 and conventional premixed combustion, on the one hand, backfire problems are avoided, safety is improved, and oxygen content is reduced while ensuring that nitrogen oxide emissions are below 30mg / Nm3. On the other hand, combined with a high emissivity coating 1-7, the water is initially heated, improving heat transfer efficiency.

[0043] The above description is merely a specific example of the present invention and does not constitute any limitation on the present invention. Obviously, those skilled in the art, after understanding the content and principles of the present invention, may make various modifications and changes in form and detail without departing from the principles and structure of the present invention; however, these modifications and changes based on the spirit of the present invention are still within the scope of protection of the claims of the present invention.

Claims

1. A micro furnace steam generator, comprising a steam-water separator (5), a ventilation chamber (1), and a combustion chamber; wherein, The combustion chamber is connected to the ventilation chamber (1), so that the combustible gas introduced into the ventilation chamber (1) can enter the combustion chamber for combustion; a first heating structure is also provided in the combustion chamber, which is used to allow water to flow through; a steam-water separator (5) is connected to the first heating structure and is used to separate liquid water and high-temperature steam; the feature is that it also includes an energy saver (6), in which a second heating structure is provided, and the second heating structure is connected to the end of the first heating structure away from the steam-water separator (5); the cavity inside the energy saver (6) is also connected to the combustion chamber, so that the high-temperature flue gas can pass through the combustion chamber and the energy saver (6) in sequence; a chimney (7) for discharging flue gas is also provided on the energy saver (6); The ventilation chamber (1) includes a gas inlet (1-1), a combustion air inlet (1-2), a mixing chamber (1-3), and a cooling structure; wherein the mixing chamber (1-3) is a hollow tubular structure; one end of the mixing chamber (1-3) is connected to the combustion chamber, and the other end of the mixing chamber (1-3) is provided with a combustion air inlet (1-2); a gas inlet (1-1) is also provided on the side of the mixing chamber (1-3); a cooling structure to prevent heat backflow is also provided between the mixing chamber (1-3) and the combustion chamber; the cooling structure is also connected to a second heating structure, so that the cooling heat-absorbing liquid flows into the second heating structure for heating; The cooling structure includes a cooling water manifold (1-5) and a labyrinthine water-cooled pipe structure (1-6); the cooling water manifold (1-5) includes an inlet manifold (1-51) and an outlet manifold (1-52) respectively located at both ends of the water-cooled pipe structure (1-6); the water-cooled pipe structure (1-6) is located between the mixing chamber (1-3) and the combustion chamber; The water-cooled pipe structure (1-6) includes several parallel water-cooled pipes arranged at equal intervals; the cross-section of the water-cooled pipes is Z-shaped, and different water-cooled pipes are located on the same horizontal plane; The water-cooled pipe is also provided with a high emissivity coating (1-7) on the side near the combustion chamber; the thickness of the high emissivity coating is 50μm~80μm and the emissivity is 0.

9.

2. The micro furnace steam generator according to claim 1, characterized in that, A hot water tank and a water pump are also provided between the second heating structure and the first heating structure; the hot water tank is used to store the liquid heated by the second heating structure; the water pump is located between the hot water tank and the first heating structure.

3. The micro furnace steam generator according to claim 1, characterized in that, A flow-dividing structure is also provided between the mixing chamber (1-3) and the cooling structure; the flow-dividing structure includes a funnel-shaped flow-dividing shell and a flow-dividing plate; wherein the side with the larger opening in the flow-dividing shell is connected to the cooling structure, and the side with the smaller opening is connected to the mixing chamber (1-3); several flow-dividing plates are provided between the flow-dividing shells.

4. The micro furnace steam generator according to claim 1, characterized in that, The first heating structure includes a radiant heating zone (2) and a convection heating surface (4); the radiant heating zone (2) and the convection heating surface (4) are arranged sequentially from top to bottom in the combustion chamber; the radiant heating zone (2) is the part where the gas is burned; the radiant heating zone (2) is connected to the convection heating surface (4); the convection heating surface (4) includes a number of finned tubes (4-1), two rows of finned tubes (4-1) form a group, and the convection heating surface (4) includes 3 to 4 groups of finned tubes (4-1); the finned tubes (4-1) in the same row of finned tubes (4-1) are distributed from top to bottom, the upstream and downstream spacing of adjacent finned tubes (4-1) is 80 mm, and the spacing between adjacent finned tubes (4-1) in the same group of finned tubes (4-1) is 50 mm.

5. A micro furnace steam generator according to claim 4, characterized in that, The finned tube (4-1) has an H-shaped cross section; the thickness of the finned tube (4-1) is 2mm, and the spacing between adjacent fins in the finned tube (4-1) is 4mm.

6. A method for generating steam, characterized in that, Based on the steam generating apparatus according to any one of claims 1 to 5, the steam generating method comprises the following steps: Step 1: Water flows into the water-cooling pipe structure (1-6), absorbs heat in the water-cooling pipe, and then enters the second heating structure; Step 2: The cooled flue gas around the second heating structure heats the water flow in the second heating structure, and then the water flow heated to 60℃~70℃ enters the hot water tank; Step 3: The water pump sends the water from the hot water tank to the first heating structure. The water flows through the convection heating surface (4) and the radiation heating area (2) of the first heating structure, and finally forms water vapor which is transported outward.

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