Biomass boiler and concentric-square-shaped four-span flue structure thereof

Abstract

The invention discloses a biomass boiler and a concentric-square-shaped four-striding flue structure thereof. The flue structure comprises a first striding flue, a second striding flue, a third striding flue and a fourth striding flue. The first crossing flue is composed of an air distribution device, a tower-shaped hearth and a platen superheater at an outlet of the tower-shaped hearth, the second crossing flue is provided with a high-temperature heat insulation separator, the third crossing flue is provided with a burnout cooling chamber flue, a convection superheater pipe set and a high-temperature economizer, and the fourth crossing flue is provided with a denitration area SCR flue, a low-temperature economizer and a tail air preheater. And the third crossing flue and the fourth crossing flue are connected through a turning flue. The flue structure is arranged in the shape like the Chinese character'hui ', the flue structure is compact, the depth ratio of the boiler is optimized on the basis that the performance of the boiler is guaranteed, the occupied area is saved, and the problem that an SCR is difficult to install and overhaul is solved.

Description

Technical Field

[0001] This application belongs to the technical field of boilers, and particularly relates to a biomass boiler and its square four-span flue structure. Background Technique

[0002] Biomass, as a clean and renewable energy source, has been widely promoted. However, existing biomass boilers generally face typical problems such as high and low temperature corrosion and fouling and plugging of heating surfaces, which seriously restrict the operation cycle of the unit. Under the background of increasingly stringent emission standards for nitrogen oxides (NO x ), a large number of biomass boilers urgently need to carry out denitrification technology transformation. To jointly solve the corrosion problem, extend the operation cycle, and improve economic benefits, limited by the既定 structure of the original boiler, optimizing the flue structure layout has become the key breakthrough for the quality improvement and efficiency increase transformation of biomass boilers. Summary of the Invention

[0003] This application aims to provide a biomass boiler and its square four-span flue structure. By optimizing the boiler depth ratio, this structure not only realizes the compactness of the structure but also jointly solves the core pain points of uneven combustion organization, fouling and plugging of heating surfaces, and high and low temperature corrosion in biomass boilers. In addition, this design effectively solves the problem of limited installation and maintenance space for the SCR denitrification system.

[0004] To achieve the above application objectives, the technical solutions adopted in this application are as follows: This application embodiment provides a square four-span flue structure of a biomass boiler, including: the first-span flue, the second-span flue, the third-span flue, and the fourth-span flue; The first-span flue consists of a air distribution device, a tower-shaped furnace, and a platen superheater at its outlet. The second-span flue is provided with a high-temperature adiabatic separator. The third-span flue is arranged with a burnout cooling chamber flue, a convection superheater tube bank, and a high-temperature economizer. The fourth-span flue is arranged with a SCR flue in the denitrification area, a low-temperature economizer, and a tail air preheater. The third-span flue and the fourth-span flue are connected by a turning flue.

[0005] Optionally, the flue structure is arranged in a "square" shape. The second-span flue is the longitudinal extension of the first-span flue. The third-span flue is the transverse extension of the second-span flue. The fourth-span flue is the longitudinal extension of the third-span flue, and the fourth-span flue and the first-span flue are horizontally aligned.

[0006] Optionally, the combustion organization of the boiler is carried out through the air distribution device, tower-shaped furnace, platen superheater arranged in the first-span flue and the high-temperature adiabatic separator arranged in the second-span flue; the high-temperature corrosion is solved by using the burnout cooling chamber flue arranged in the third-span flue and the subsequent convection superheater tube bank; a low-temperature economizer and a SCR flue in the denitrification area are arranged in the upper part of the fourth-span flue, and a tail air preheater is arranged in the lower part.

[0007] Optionally, the flue gas generated by the boiler passes from bottom to top through the tower-shaped furnace and screen-type superheater in the first flue, and then through the high-temperature insulation separator in the second flue for flue gas separation. The separated flue gas flows from top to bottom through the combustion cooling chamber flue and convection superheater tube group and high-temperature economizer in the third flue, and then through the diversion flue into the denitrification zone SCR device and tail air preheater in the fourth flue, and finally into the boiler tail environmental protection equipment before entering the chimney.

[0008] This application also provides a biomass boiler, including the above-mentioned biomass boiler with a U-shaped four-span flue structure.

[0009] Compared with the prior art, the beneficial effects of the embodiments of this application are: The U-shaped four-span flue structure provided in this application embodiment is suitable for biomass circulating fluidized bed boilers. It has a compact structure, reasonable layout, and saves floor space and investment. It can solve the problem of excessive depth-to-width ratio and unstable steel structure in small boilers. It is especially suitable for solving the problem of insufficient original foundation for boiler renovation, expansion and addition of SCR device. A burnout cooling chamber flue is adopted in the upper part of the third flue to reduce the flue gas temperature and solve the problem of coke and ash accumulation on the tail heating surface of biomass boilers. The denitrification zone SCR device is arranged in the upper part of the fourth flue, which solves the previous problems of SCR maintenance and installation difficulties. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0011] Figure 1 This is a top view of a U-shaped four-span flue structure of a biomass boiler provided by the present invention.

[0012] Figure 2 These are elevation views of a single-span flue and a double-span flue provided by the present invention.

[0013] Figure 3 These are elevation views of the two-span and three-span flues provided by this invention.

[0014] Figure 4 These are elevation views of the three-span and four-span flues provided by this invention.

[0015] Illustration: First span flue 1, second span flue 2, third span flue 3, fourth span flue 4, air distribution device 5, tower-shaped furnace 6, screen-type superheater 7, high-temperature insulation separator 8, burnout cooling chamber flue 9, convection superheater tube assembly 10, high-temperature economizer 11, diverting flue 12, denitrification zone SCR flue 13, low-temperature economizer 14, tail air preheater 15. Detailed Implementation

[0016] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0017] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0018] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0019] To illustrate the technical solution described in this application, specific embodiments are provided below.

[0020] Please see Figures 1 to 4 As shown, this embodiment provides a U-shaped four-span flue structure for a biomass boiler, including a first flue 1, a second flue 2, a third flue 3, and a fourth flue 4. This structure differs from the traditional longitudinal boiler arrangement, where each span is arranged longitudinally from front to back along the depth direction, typically three spans. Biomass boilers require additional combustion cooling chambers to prevent ash accumulation and slag buildup, and SCR devices are added at the tail end for environmental upgrades, all of which necessitate extending the tail flue. The original three-span structure is insufficient to meet these requirements, necessitating a four-span configuration. If all four flues are arranged longitudinally along the depth direction, the boiler's depth dimension becomes excessively large, affecting the overall boiler island layout. This application adopts a U-shaped structure, resulting in a compact boiler structure that saves floor space while still meeting various boiler performance requirements.

[0021] Among them, the first cross flue 1 consists of an air distribution device 5, a tower-shaped furnace 6 and a platen superheater 7 at its outlet. The second cross flue 2 is provided with a high-temperature adiabatic separator 8. The third cross flue 3 is arranged with a burnout cooling chamber flue 9, a convective superheater tube bank 10 and a high-temperature economizer 11. The fourth cross flue 4 is arranged with a denitrification area SCR flue 13, a low-temperature economizer 14 and an air preheater 15 at the tail. The third cross flue 3 and the fourth cross flue 4 are connected by a turning flue 12.

[0022] The above flue structure is arranged in a "return" shape. The second cross flue 2 is a longitudinal extension of the first cross flue 1. The third cross flue 3 is a transverse extension of the second cross flue 2. The fourth cross flue 4 is a longitudinal extension of the third cross flue 3, and the fourth cross flue 4 and the first cross flue 1 are horizontally aligned.

[0023] The organization of boiler combustion is carried out through the air distribution device 5, the tower-shaped furnace 6, the platen superheater 7 arranged in the first cross flue 1 and the high-temperature adiabatic separator 8 arranged in the second cross flue 2. The burnout cooling chamber flue 9 arranged in the third cross flue 3 and the subsequent convective superheater tube bank 10 are used to solve the problem of high-temperature corrosion. The low-temperature economizer 14 and the denitrification area SCR flue 13 are arranged in the upper part of the fourth cross flue 4, and the air preheater 15 at the tail is arranged in the lower part to solve the problem of difficult installation and maintenance of the boiler SCR. The four flues are arranged in a "return" shape, saving floor area, especially suitable for the situation where the foundation is limited during boiler renovation.

[0024] In another embodiment of the present application, a biomass boiler is further provided, including the above-mentioned four-cross flue structure in a return shape.

[0025] The working principle of a biomass boiler and its four-cross flue structure in a return shape provided by the above embodiment is as follows: The flue gas generated by the boiler sequentially passes through the tower-shaped furnace 6 and the platen superheater 7 in the first cross flue 1 from bottom to top, and then passes through the high-temperature adiabatic separator 8 in the second cross flue 2 for flue gas separation. The separated flue gas flows through the burnout cooling chamber flue 9, the convective superheater tube bank 10 and the high-temperature economizer 11 in the third cross flue 3 from top to bottom, and then enters the denitrification area SCR flue 13 and the air preheater 15 at the tail in the fourth cross flue 4 through the turning flue 12, and finally enters the chimney after entering the environmental protection equipment at the tail of the boiler.

[0026] A biomass boiler and its four-cross flue structure in a return shape provided by the embodiment of the present application have the following advantages: The U-shaped four-span flue structure is suitable for biomass circulating fluidized bed boilers. It has a compact structure, reasonable layout, and saves floor space and investment. It can solve the problem of excessive depth-to-width ratio and unstable steel structure in small boilers. It is especially suitable for solving the problem of insufficient original foundation for boiler renovation and expansion and the addition of SCR devices. The combustion cooling chamber flue 9 is used in the upper part of the third flue 3 to reduce the flue gas temperature and solve the problem of coke and ash accumulation on the tail heating surface of biomass boilers. The denitrification zone SCR flue 13 is arranged in the upper part of the fourth flue 4, which solves the previous problems of SCR maintenance and installation difficulties.

[0027] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A U-shaped four-span flue structure for a biomass boiler, characterized in that, Comprising: The first cross flue, the second cross flue, the third cross flue, and the fourth cross flue; The first cross flue consists of an air distribution device, a tower-shaped furnace, and a platen superheater at its outlet. The second cross flue is provided with a high-temperature adiabatic separator. The third cross flue is arranged with a burnout cooling chamber flue, a convection superheater tube bank, and a high-temperature economizer. The fourth cross flue is arranged with a denitration zone SCR flue, a low-temperature economizer, and an air preheater at the tail. The third cross flue and the fourth cross flue are connected by a turning flue.

2. The U-shaped four-span flue structure of the biomass boiler according to claim 1, characterized in that, The flue structure is arranged in a "return" shape. The second cross flue is the longitudinal extension of the first cross flue. The third cross flue is the transverse extension of the second cross flue. The fourth cross flue is the longitudinal extension of the third cross flue, and the fourth cross flue and the first cross flue are horizontally aligned.

3. The U-shaped four-span flue structure of the biomass boiler according to claim 2, characterized in that, The organization of boiler combustion is carried out through the air distribution device, the tower-shaped furnace, the platen superheater arranged in the first cross flue, and the high-temperature adiabatic separator arranged in the second cross flue. The burnout cooling chamber flue arranged in the third cross flue and the subsequent convection superheater tube bank are used to solve high-temperature corrosion. The low-temperature economizer and the denitration zone SCR flue are arranged in the upper part of the fourth cross flue, and the air preheater at the tail is arranged in the lower part.

4. The U-shaped four-span flue structure of the biomass boiler according to claim 3, characterized in that, The flue gas generated by the boiler passes through the tower-shaped furnace and the platen superheater in the first cross flue from bottom to top in sequence, and then passes through the high-temperature adiabatic separator in the second cross flue for flue gas separation. The separated flue gas flows through the burnout cooling chamber flue, the convection superheater tube bank, and the high-temperature economizer in the third cross flue from top to bottom. Subsequently, it enters the denitration zone SCR flue and the air preheater at the tail in the fourth cross flue through the turning flue, and finally enters the chimney after entering the environmental protection equipment at the tail of the boiler.

5. A biomass boiler, characterized in that, Comprising the "return" shaped four-cross flue structure of the biomass boiler according to any one of claims 1-4.

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