Novel low-nitrogen water-cooling premixed combustion steam boiler
By rationally arranging tube bundles and embedding corrugated plates, the combustion process is optimized, solving the problems of low space utilization and high NOx generation in traditional steam boilers, and achieving low-cost and high-efficiency combustion.
Patent Information
- Application Number
- CN202511782698.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-30
- Publication Date
- 2026-02-27
AI Technical Summary
Traditional steam boilers suffer from problems such as large flame size, low space utilization, high metal consumption, high cost, and high NOx generation.
By employing a rational arrangement of tube bundles, using smooth tube bundles and finned tube bundles for cooling, and embedding corrugated plates between water-cooled tube banks to form gas flow gaps, combined with a tail-end waste heat recovery device, the combustion process is optimized.
It effectively utilizes space, reduces flame temperature, decreases NOx generation, and lowers metal consumption and costs.
Smart Images
Figure CN121576566A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of boiler technology, specifically to a novel low-NOx water-cooled premixed combustion steam boiler. Background Technology
[0002] Traditional steam boilers use diffusion combustion, which produces a large flame and requires a large combustion space, resulting in bulky boilers, high metal consumption, and high costs.
[0003] Currently available water-cooled premixed combustion steam boilers use a vertical water tube structure. Although some have a shrinkage combustion structure, the tube bundle arrangement is unreasonable, the space utilization is not high, and the flame temperature is high, resulting in a large amount of NOx generation. Summary of the Invention
[0004] To address the aforementioned technical problems, this invention provides a novel low-NOx water-cooled premixed combustion steam boiler, which rationally arranges the tube bundles, effectively utilizes space, and reduces flame temperature.
[0005] The technical solution is as follows: A novel water-cooled premixed steam boiler structure includes a gas premixing device, a furnace body, and a tail-end waste heat recovery device. The gas premixing device includes a fan and a mixer. A mixing box is connected to one side of the furnace body, and the outlet of the mixing box extends into the furnace body. A convection heating component is installed inside the furnace body. A uniform air distribution plate and an ignition device are installed at the outlet of the mixing box. The convection heating component includes a membrane wall tube forming a flue gas channel, a smooth tube bundle and a finned tube bundle installed in the flue gas channel, downcomers installed on both sides of the flue gas channel, and a front water-cooled tube bank and a rear water-cooled tube bank installed at the uniform air distribution plate. The flue gas channel is sequentially divided into a front transition zone, a middle diffusion zone, and a rear closing zone along the flue gas flow direction. The front transition zone is provided with the front water-cooled tube bank and the rear water-cooled tube bank. The middle diffusion zone is provided with the smooth tube bundle. The rear closing zone is provided with part of the smooth tube bundle and all of the finned tube bundle.
[0006] A further feature is that a first strip-shaped gap is provided between adjacent water-cooling pipes of the front water-cooling pipe bank, and a corrugated plate layer is embedded in the first strip-shaped gap. The corrugated plate layer is formed by pressing multiple corrugated plates and leaving gas flow gaps. The second strip gap between adjacent water-cooling pipes in the rear water-cooling pipe bank corresponds to the position of the first strip gap; The width of the second strip-shaped gap is not less than the width of the first strip-shaped gap; A corrugated plate limiting block is installed inside the first strip-shaped gap; The water-cooling pipes in the front water-cooling pipe bank are thick-walled pipes, and both sides of the thick-walled pipes are flat.
[0007] The furnace body includes an upper end cap, a middle cylinder, and a lower end cap. An upper tube sheet is provided between the upper end cap and the middle cylinder to form an upper cavity. A lower tube sheet is provided between the lower end cap and the middle cylinder to form a lower cavity. The upper cavity is provided with a main body water inlet and a main steam outlet. The lower cavity is provided with a drain outlet. The tail-end waste heat recovery device includes an upper header of the energy-saving device, a serpentine heat exchange tube of the energy-saving device, and a lower header of the energy-saving device.
[0008] By adopting this invention, the convection heating components are rationally designed, and smooth tube bundles and finned tube bundles are used to cool the flue gas. The downcomers are distributed on both sides of the flue gas channel to effectively utilize the space. A front water-cooled tube bank and a rear water-cooled tube bank are set at the outlet of the mixing box to further cool the flame and reduce the flame temperature, which can reduce NOx generation. Attached Figure Description
[0009] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a cross-sectional view of the interior of the furnace body. Figure 3 This is a schematic diagram of the structure of the mixing box; Figure 4 This is a schematic diagram of the side of the corrugated plate layer. Detailed Implementation
[0010] See Figures 1 to 4 As shown, a novel low-NOx water-cooled premixed combustion steam boiler includes a gas premixing device, a boiler body 2, and a tail-end waste heat recovery device. The gas premixing device includes a fan 20 and a mixer 19. A mixing box 18 is connected to one side of the boiler body 2, and the outlet of the mixing box 18 extends into the boiler body. A convection heating assembly is installed inside the boiler body 2. A uniform air distribution plate 28 and an ignition device 31 are installed at the outlet of the mixing box 18. The convection heating assembly includes a membrane wall tube 25 forming a flue gas passage and a gas distribution plate 28 installed at the outlet of the mixing box 18. The flue gas passage includes smooth tube bundles 26 and finned tube bundles 27, downcomers 24 on both sides of the passage, and front and rear water-cooled tube banks 5 and 23 located at the air distribution plate 28. The passage is divided into a front transition zone, a middle diffusion zone, and a rear closing zone along the flue gas flow direction. The front transition zone contains the front and rear water-cooled tube banks 5 and 23, the middle diffusion zone contains smooth tube bundles 26, and the rear closing zone contains some smooth tube bundles 26 and all of the finned tube bundles 17. A first strip-shaped gap is provided between adjacent water-cooled tubes in the front water-cooled tube bank 5. A corrugated plate layer 29 is embedded in this first strip-shaped gap. The corrugated plate layer 29 is formed by pressing multiple corrugated plates together and leaving gas flow gaps. It is formed by the concave and convex surfaces of adjacent corrugated plates, such as... Figure 4As shown, it can serve as a flame arrestor. The second strip-shaped gap between adjacent water-cooling pipes of the rear water-cooling pipe row 5 corresponds to the position of the first strip-shaped gap. It will not block the flame, but only serves to cool the flame; the width of the second strip-shaped gap is not less than the width of the first strip-shaped gap.
[0011] Along the length of the water-cooling pipe, multiple corrugated plate limiting blocks 30 are installed within the first strip-shaped gap to ensure the installation accuracy of the corrugated plate and prevent its position from shifting. For ease of installation, the water-cooling pipes in the front water-cooling pipe row 5 are thick-walled pipes with flat sides, allowing the corrugated plate to easily snap into place. Once against the corrugated plate limiting blocks 30, the plate is properly seated. The corrugated plate limiting blocks 30 are directly welded to the flat sides. The corrugated plate is made of stainless steel.
[0012] Air is drawn in by fan 20 and pressurized before entering mixer 19. Combustion enters from mixer 19, mixes with air, and then enters the front water-cooled tube bank 5 through mixing box 18. It burns after passing through the gas flow gap formed by water-cooled tubes and corrugated plates, ensuring that the mixed gas flow velocity is not lower than its combustion velocity at low load. The flame is cooled by the second drain cooling pipe 23, generating high-temperature flue gas. The high-temperature flue gas enters the middle diffusion zone from the front transition zone in the flue gas channel formed by two sets of membrane wall tubes 25. Due to the slightly larger flow area, the flue gas flow velocity is reduced to a certain extent. It first washes the smooth tube bundle 26 to increase the contact time, and then enters the rear closing zone. The flue gas flow velocity increases and quickly washes the finned tube bundle 27. The fins increase the contact area and effectively reduce the flue gas temperature. It enters the tail waste heat recovery device through connecting flue 10 for further heat exchange, and finally is discharged from boiler outlet 9. The tail waste heat recovery device includes the upper header 6 of the economizer, the serpentine heat exchange tube 7 of the economizer, and the lower header 8 of the economizer.
[0013] The furnace body 2 includes an upper end cap 21, a middle cylinder 4, and a lower end cap 22. An upper tube plate 16 is provided between the upper end cap 21 and the middle cylinder 4 to form an upper cavity 1. A lower tube plate 17 is provided between the lower end cap 22 and the middle cylinder 4 to form a lower cavity 3. The upper cavity 1 is provided with a main body water inlet 11, a main steam outlet 12, and an upper inspection hole 13. The lower cavity 3 is provided with a drain outlet 15 and a lower inspection hole 14.
[0014] Softened water enters from the lower header 8 of the economizer, absorbs heat through the serpentine heat exchange tubes 7 of the economizer, and is collected in the upper header 6 of the economizer. Then it enters the upper chamber 1 through the main body inlet 11, and enters the lower chamber 3 through the downcomers 24 distributed on both sides of the upper chamber 1, which are evenly distributed and make efficient use of the space. In the smooth tube bundle 26, finned tube bundle 27 and membrane wall tube 25, it absorbs heat and becomes saturated steam, which returns to the upper chamber 1. After steam-water separation, it is output from the main steam outlet 12.
Claims
1. A novel water-cooled premixed steam boiler structure, comprising a gas premixing device, a furnace body, and a tail-end waste heat recovery device, wherein the gas premixing device includes a fan and a mixer, a mixing box is connected to one side of the furnace body, the outlet of the mixing box extends into the furnace body, a convection heating component is disposed within the furnace body, and a uniform air distribution plate and an ignition device are disposed at the outlet of the mixing box, characterized in that, The convection heating assembly includes a membrane wall tube forming a flue gas channel, a smooth tube bundle and a finned tube bundle disposed within the flue gas channel, downcomers disposed on both sides of the flue gas channel, and a front water-cooled tube bank and a rear water-cooled tube bank disposed at the uniform air distribution plate. The flue gas channel is sequentially divided into a front transition zone, a middle diffusion zone, and a rear closing zone along the flue gas flow direction. The front transition zone is provided with the front water-cooled tube bank and the rear water-cooled tube bank, the middle diffusion zone is provided with the smooth tube bundle, and the rear closing zone is provided with part of the smooth tube bundle and all of the finned tube bundle.
2. The novel water-cooled premixed steam boiler structure according to claim 1, characterized in that, A first strip-shaped gap is provided between adjacent water-cooling pipes of the front water-cooling pipe bank. A corrugated plate layer is embedded in the first strip-shaped gap. The corrugated plate layer is formed by pressing multiple corrugated plates and leaving gaps for gas flow.
3. The novel water-cooled premixed steam boiler structure according to claim 2, characterized in that, The second strip gap between adjacent water-cooling pipes in the rear water-cooling pipe bank corresponds to the position of the first strip gap.
4. The novel water-cooled premixed steam boiler structure according to claim 3, characterized in that, The width of the second strip gap is not less than the width of the first strip gap.
5. The novel water-cooled premixed steam boiler structure according to claim 2, characterized in that, A corrugated plate limiting block is installed inside the first strip-shaped gap.
6. The novel water-cooled premixed steam boiler structure according to claim 1, characterized in that, The water-cooling pipes in the front water-cooling pipe bank are thick-walled pipes, and both sides of the thick-walled pipes are flat.
7. The novel water-cooled premixed steam boiler structure according to claim 1, characterized in that, The furnace body includes an upper end cap, a middle cylinder, and a lower end cap. An upper tube sheet is provided between the upper end cap and the middle cylinder to form an upper cavity, and a lower tube sheet is provided between the lower end cap and the middle cylinder to form a lower cavity. The upper cavity is provided with a main body water inlet and a main steam outlet, and the lower cavity is provided with a drain outlet.
8. The novel water-cooled premixed steam boiler structure according to claim 1, characterized in that, The tail-end waste heat recovery device includes an upper header of the energy-saving device, a serpentine heat exchange tube of the energy-saving device, and a lower header of the energy-saving device.