A biomass boiler air preheater anticorrosion device

Abstract

The utility model discloses a kind of biomass boiler air preheater anticorrosion device, including air preheater, still including the guide air duct being connected with air preheater, guide air duct includes first air duct and second air duct, second air duct is connected in the inlet end of first air duct, the air preheater includes shell and the flue pipe assembly being set in the shell, flue pipe assembly includes tube bundle and the tube sheet being fixed in the both sides of tube bundle, the air preheater is vertically placed, the inner wall of the air preheater is provided with base layer, intermediate insulating layer is fixed outside the base layer, intermediate insulating layer outside fixedly set has metal reinforcing layer, the metal reinforcing layer closely adheres to intermediate insulating layer, the metal reinforcing layer and the shell of the air preheater form integral structure, first air duct is indoor air duct, second air duct is hot air return pipe, hot air return pipe is connected with the hot air outlet of the air preheater.

Description

Technical Field

[0001] This utility model belongs to the field of air preheater technology, specifically relating to an anti-corrosion device for a biomass boiler air preheater. Background Technology

[0002] Currently, biomass boiler fuels contain sulfur to varying degrees. When fuels with high sulfur content are burned, most of the sulfur in the fuel is converted into sulfur dioxide after combustion. Under certain conditions, a small portion of it is further oxidized into sulfur trioxide gas. Sulfur trioxide gas can combine with water vapor to form sulfuric acid vapor, whose condensation dew point temperature is as high as 120°C or higher. The higher the acid content of the flue gas, the higher the dew point temperature, and the more severe the corrosion and ash blockage.

[0003] Most biomass boilers are currently equipped with air preheaters. When the temperature of the air preheater tube wall is lower than the dew point of the generated sulfuric acid, the sulfuric acid condenses on the tube wall, causing corrosion, which is called low-temperature corrosion. The degree of corrosion on the metal wall depends on the amount and concentration of sulfuric acid condensation and the temperature of the metal wall. The sulfuric acid acts like a film, adhering to the tube wall and corroding it, while continuously attracting soot to form various sulfates, which gradually thicken. This is low-temperature slagging.

[0004] Currently, the designed flue gas temperature of boilers equipped with air preheaters is generally 130-160℃, while the flue gas temperature of some special fuel boilers (such as waste-to-energy boilers, biomass boilers, coke oven gas boilers, etc.) is even higher. Due to the low inlet air temperature at the cold air end of the air preheater, the wall temperature of the cold air inlet tube of the air preheater is generally lower than the acid dew point of the flue gas, resulting in severe tube corrosion. Long-term operation will inevitably have a great impact on the safe operation and service life of the boiler.

[0005] In view of the above factors, a corrosion prevention device for a biomass boiler air preheater is provided. By increasing the air temperature at the inlet of the air preheater, the wall temperature of the cold end heat exchange surface of the preheater is increased, preventing condensation corrosion. The inner wall of the air preheater is provided with a base layer, an intermediate insulation layer is fixed outside the base layer, and a metal reinforcing layer is fixed outside the intermediate insulation layer. The metal reinforcing layer is closely attached to the intermediate insulation layer, and the metal reinforcing layer and the shell of the air preheater form an integral structure. By insulating the air preheater, dew point corrosion caused by flue gas encountering low temperatures is avoided. Utility Model Content

[0006] The purpose of this invention is to provide a corrosion prevention device for a biomass boiler air preheater to solve the problems mentioned in the background art.

[0007] The purpose of this utility model is achieved through the following technical solution: a corrosion prevention device for a biomass boiler air preheater, including an air preheater and a guide duct connected to the air preheater, the guide duct including a first duct and a second duct, the second duct being connected to the inlet end of the first duct;

[0008] The air preheater includes a housing and a flue assembly disposed within the housing. The flue assembly includes a tube bundle and tube plates fixed on both sides of the tube bundle. The flue assembly is placed vertically.

[0009] The inner wall of the air preheater is provided with a base layer, an intermediate insulation layer is fixed to the outside of the base layer, and a metal reinforcing layer is fixed to the outside of the intermediate insulation layer. The metal reinforcing layer is closely attached to the intermediate insulation layer, and the metal reinforcing layer and the shell of the air preheater form an integral structure.

[0010] Furthermore, the first air duct is an indoor air duct, and the second air duct is a hot air return pipe, which is connected to the hot air outlet of the air preheater.

[0011] Furthermore, the inlet of the first air duct is located inside the biomass boiler room, and air is supplied to the biomass boiler room by the first air duct;

[0012] The main body of the first air duct is located outdoors and is supported by a steel truss structure.

[0013] Furthermore, the entrance to the first air duct is located inside the biomass boiler room, and is an open and independent area.

[0014] Furthermore, the entrance to the first air duct is located inside the biomass boiler room, and is an open and independent area.

[0015] Furthermore, the base layer is made of composite silicate paste insulation material, and the thickness of the base layer is less than 15mm.

[0016] Furthermore, the intermediate insulation layer comprises at least two layers of composite silicate fiberboard, each layer having a thickness of 20 mm.

[0017] Furthermore, the metal reinforcing layer is made of the same material as the air preheater, and its thickness is the same as the shell thickness of the air preheater.

[0018] Furthermore, the tube bundle in the flue assembly is a composite tube bundle, which includes two different metal materials. The composite tube bundle is made of stainless steel and carbon structural steel through non-destructive pressure synchronous bonding.

[0019] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0020] The first air duct of this invention is an indoor air duct, and the second air duct is a hot air return pipe. The hot air return pipe is connected to the hot air outlet of the air preheater. The inlet of the first air duct is located inside the biomass boiler room, and air is supplied from the first air duct inside the biomass boiler room. The main body of the first air duct is located outdoors and is supported by a steel structure truss. By increasing the air temperature at the inlet of the air preheater, the wall temperature of the cold end heat exchange surface of the preheater is increased, preventing condensation and corrosion.

[0021] Furthermore, the inner wall of the air preheater is provided with a base layer, an intermediate insulation layer is fixed to the outside of the base layer, and a metal reinforcing layer is fixed to the outside of the intermediate insulation layer. The metal reinforcing layer is closely attached to the intermediate insulation layer, and the metal reinforcing layer and the shell of the air preheater form an integral structure. By insulating the air preheater, dew point corrosion caused by low temperature is avoided.

[0022] This invention not only improves the thermal efficiency of air preheaters in biomass boilers, but also prevents dew point corrosion. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the connection between the air preheater and the fan duct of this utility model;

[0024] Figure 2 This is a schematic diagram of the connection between the first and second air ducts of this utility model;

[0025] Figure 3 This is a schematic cross-sectional view of the air preheater of this utility model;

[0026] Figure 4 This is a schematic cross-sectional view of the inner wall of the air preheater of this utility model;

[0027] Figure 5 This is a schematic cross-sectional view of the tube bundle of this utility model. Detailed Implementation

[0028] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the protection scope of the present utility model.

[0029] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0030] In the description of this utility model, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0031] like Figure 1-5 As shown, a corrosion prevention device for a biomass boiler air preheater includes an air preheater 1 and a guide duct 2 connected to the air preheater 1. The guide duct 2 includes a first duct 21 and a second duct 22, with the second duct 22 connected to the inlet end of the first duct 21.

[0032] The air preheater 1 includes a housing 11 and a flue assembly 12 disposed within the housing 11. The flue assembly 12 includes a tube bundle 13 and tube plates 14 fixed on both sides of the tube bundle 13. The flue assembly 13 is placed vertically. The air preheater 1 has a horizontal air inlet and an air outlet. The air preheater 1 is also provided with a flue gas inlet and a flue gas outlet.

[0033] The main body of the first air duct 21 is located outdoors, while the air inlet of the first air duct 21 is located inside the biomass boiler room. The exterior of the first air duct 21 is coated with composite silicate paste insulation material with a thickness of at least 15mm, and the outer layer is wrapped with composite silicate fiberboard and bound with steel wire.

[0034] The inner wall of the air preheater 1 is provided with a base layer 15, an intermediate insulation layer 16 is fixed to the outside of the base layer 15, and a metal reinforcing layer 17 is fixed to the outside of the intermediate insulation layer 16. The metal reinforcing layer 17 is closely attached to the intermediate insulation layer 16, and the metal reinforcing layer 17 and the shell 11 of the air preheater 1 form an integral structure.

[0035] To facilitate use, the air inlet of the primary air fan is modified to increase the air inlet temperature by changing the air duct. The first air duct 21 is an indoor air duct, and the second air duct 22 is a hot air return pipe. The hot air return pipe is connected to the hot air outlet of the air preheater 1, and the other end of the hot air return pipe is connected to the fan inlet of the first air duct 21. The inlet of the first air duct 21 is located inside the biomass boiler room 3, and air is supplied from the first air duct 21 inside the biomass boiler room 3. The main body of the first air duct 21 is located outdoors and is supported by a steel structure truss.

[0036] For ease of use, a steam-heated air heater, as disclosed in the prior art, can be installed at the front end of the air preheater and the front end of the fan for further addition treatment (the prior art of steam-heated air heaters will not be described in detail here).

[0037] To facilitate insulation treatment inside the air preheater during use, the base layer 15 is made of composite silicate paste insulation material, and the thickness of the base layer 15 is less than 15mm; the intermediate insulation layer 16 includes at least two layers of composite silicate fiberboard, and each layer is 20mm thick; the metal reinforcing layer 17 is made of the same material as the air preheater 1, and its thickness is the same as the shell thickness of the air preheater 1.

[0038] The intermediate insulation layer 16 includes at least two layers of composite silicate fiberboard connected to the shell by self-tapping screws. A metal reinforcing layer is provided on the outside of the intermediate insulation layer 16. The metal reinforcing layer is fixed to the shell to form an inner layer with an insulation structure. The inner layer with an insulation structure is on the inner wall of the air preheater.

[0039] The above-mentioned method of setting a base layer and an intermediate insulation layer to improve the insulation effect, reduce the heat loss of the preheater, and ensure the wall temperature of the air preheater not only improves the thermal efficiency of the heating furnace, but also plays a very important role in preventing dew point corrosion.

[0040] To improve the corrosion resistance of the tube bundle under use, the tube bundle in the flue assembly is a composite tube bundle, which includes two different metal materials. The composite tube bundle is made of stainless steel 18 and carbon structural steel 19 through non-destructive pressure synchronous bonding.

[0041] The interior of the composite tube bundle is coated with an anti-corrosion material, which is an anti-corrosion coating made of epoxy resin composite material.

[0042] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0043] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A corrosion prevention device for a biomass boiler air preheater, comprising an air preheater (1), characterized in that: It also includes a guide duct (2) connected to the air preheater (1), the guide duct (2) including a first duct (21) and a second duct (22), the second duct (22) being connected to the inlet end of the first duct (21); The air preheater (1) includes a shell and a flue assembly disposed in the shell. The flue assembly includes a tube bundle and tube plates fixed on both sides of the tube bundle. The flue assembly is placed vertically. The inner wall of the air preheater (1) is provided with a base layer, an intermediate insulation layer is fixed on the outside of the base layer, a metal reinforcing layer is fixed on the outside of the intermediate insulation layer, the metal reinforcing layer is closely attached to the intermediate insulation layer, and the metal reinforcing layer and the shell of the air preheater (1) form an integral structure.

2. The anti-corrosion device for the biomass boiler air preheater according to claim 1, characterized in that: The first air duct (21) is an indoor air duct, and the second air duct (22) is a hot air return pipe, which is connected to the hot air outlet of the air preheater (1).

3. The anti-corrosion device for the biomass boiler air preheater according to claim 2, characterized in that: The inlet of the first air duct (21) is located inside the biomass boiler room, and air is supplied to the biomass boiler room by the first air duct (21); The main body of the first air duct (21) is set outdoors and supported by a steel truss.

4. The anti-corrosion device for the biomass boiler air preheater according to claim 2, characterized in that: The entrance to the first air duct (21) is located inside the biomass boiler room and is an open and independent area.

5. The anti-corrosion device for the air preheater of a biomass boiler according to claim 4, characterized in that: The base layer uses composite silicate paste insulation material, and the thickness of the base layer is less than 15mm.

6. The anti-corrosion device for the air preheater of a biomass boiler according to claim 5, characterized in that: The intermediate insulation layer comprises at least two layers of composite silicate fiberboard, each layer being 20 mm thick.

7. The anti-corrosion device for the air preheater of a biomass boiler according to claim 6, characterized in that: The metal reinforcing layer is made of the same material as the air preheater (1), and its thickness is the same as the shell thickness of the air preheater (1).

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