High-efficiency heat recovery type boiler air preheater

Abstract

The utility model relates to a boiler air preheater technical field discloses a kind of high-efficiency heat recovery type boiler air preheater. To solve the technical problem of the heat exchange efficiency of conventional air preheater in prior art is lower, especially when handling high-temperature flue gas, heat recovery is not sufficient. The boiler of the utility model includes hearth for fuel combustion to generate high-temperature flue gas, the outlet of hearth is sequentially provided with superheater, economizer and at least one air preheater along flue gas flow direction;Steam inlet end of superheater is connected with steam drum outlet, superheater outlet end is connected with superheated steam output pipeline, steam drum lower part is connected with hearth water-cooled wall, inlet of steam drum is connected with economizer, economizer feedwater inlet is communicated with water source, air preheater is located in downstream flue gas passage of economizer, air inlet of air preheater is connected with air supply fan. The utility model significantly increases heat exchange area and fluid residence time by wide channel design and S-shaped flow path, improves heat exchange efficiency.

Description

Technical Field

[0001] This utility model relates to the field of boiler air preheater technology, and in particular to a high-efficiency heat recovery type boiler air preheater. Background Technology

[0002] A boiler is an energy conversion device. The energy input to a boiler includes the chemical energy of fuel and electrical energy. The boiler outputs steam, high-temperature water, or organic heat carriers with a certain amount of thermal energy. The hot water or steam produced in a boiler can directly provide the heat energy needed for industrial production and daily life, or it can be converted into mechanical energy through a steam power unit, or further converted into electrical energy through a generator. Boilers that produce steam are called steam boilers, often simply referred to as boilers, and are widely used in thermal power plants, ships, locomotives, and industrial and mining enterprises. An air preheater is a heat exchange surface in the boiler's tail flue that preheats the air entering the boiler to a certain temperature through internal heat exchange fins. It is a device used to improve the boiler's heat exchange performance and reduce energy consumption. Air preheaters are generally divided into three types: plate type, rotary type, and tubular type.

[0003] Chinese patent document 202310885094.4 discloses an air preheater and boiler system, including a preheating body, an air preheating section, and a heat exchange device. The preheating body is used to exchange heat between the flue gas and the air; the air preheating section is connected to the preheating body, and the heat exchange device is installed inside the air preheating section. Cold air is preheated by exchanging heat with the flue gas that has not fully exchanged heat through the heat exchange device, and the preheated cold air is injected into the preheating body to exchange heat with the flue gas.

[0004] However, the above-mentioned solutions have at least the following technical problems during implementation: traditional air preheaters have low heat exchange efficiency, especially when dealing with high-temperature flue gas, resulting in insufficient heat recovery. Therefore, there is an urgent need to propose a high-efficiency heat recovery type boiler air preheater. Summary of the Invention

[0005] In view of the above technical problems, this disclosure provides a high-efficiency heat recovery type boiler air preheater, which solves the technical problem of low heat exchange efficiency of traditional air preheaters in the prior art, especially the insufficient heat recovery when dealing with high-temperature flue gas.

[0006] According to one aspect of this disclosure, a high-efficiency heat recovery type boiler air preheater is provided. The boiler includes a furnace for generating high-temperature flue gas through fuel combustion. A superheater, an economizer, and at least one air preheater are sequentially arranged along the flue gas flow direction at the outlet of the furnace. The steam inlet end of the superheater is connected to the steam drum outlet, and the superheater outlet end is connected to a superheated steam output pipe. The lower part of the steam drum is connected to the furnace water-cooled wall, the inlet of the steam drum is connected to the economizer, the feedwater inlet of the economizer is connected to a water source, and the air preheater is located in the flue gas passage downstream of the economizer. The air inlet of the air preheater is connected to a blower.

[0007] In some embodiments of this disclosure, the air preheater is a wide-channel plate heat exchanger, a tubular heat exchanger, a rotary heat exchanger, or a heat pipe air heat exchanger.

[0008] In some embodiments of this disclosure, a dust collector is also included, wherein the flue gas outlet of the air preheater is connected to the dust collector to remove particulate matter from the flue gas before it is discharged.

[0009] In some embodiments of this disclosure, the wide-channel plate heat exchanger includes a heat exchange core, which includes a plurality of heat exchange plates arranged side by side. Each heat exchange plate is a single plate welded together by a plurality of weld points to form a double-sided raised structure. There is a corrugated wide-channel inner channel between the two single plates and an outer channel between adjacent heat exchange plates.

[0010] In some embodiments of this disclosure, the solder joints are arranged in an alternating grid pattern.

[0011] In some embodiments of this disclosure, multiple guide strips are staggered on the heat exchange plates along the flow direction of the fluid in the inner and / or outer channels, so that the fluid moves forward in an S-shaped circulation within the inner and / or outer channels.

[0012] In some embodiments of this disclosure, the length of the guide strip is less than the length of the heat exchange plate, and the number of guide strips is an odd number.

[0013] The beneficial effects of this utility model are as follows:

[0014] The air preheater employs a wide-channel plate heat exchanger structure with a corrugated wide-channel design in its inner passages. This increases the fluid flow space, reduces fluid flow resistance, and simultaneously increases the heat exchange area, thereby significantly improving heat exchange efficiency. Guide strips on the heat exchange plates guide the fluid forward in an S-shaped circulation within the inner and outer channels. This increases the fluid residence time and heat exchange path, further improving heat exchange efficiency. The weld points are arranged in a staggered grid pattern, which not only enhances the structural stability of the heat exchange plates but also optimizes the uniformity of fluid flow, avoiding excessively high local thermal resistance and further improving heat exchange performance. Through the air preheater, heat from the flue gas is effectively recovered for preheating the air entering the boiler. This reduces the amount of fuel required for boiler combustion, thereby lowering system energy consumption. The increased temperature of the preheated air allows for more efficient combustion upon entering the combustion system, further improving combustion efficiency and reducing fuel consumption. Air preheaters can be wide-channel plate heat exchangers, tube heat exchangers, rotary heat exchangers, or heat pipe air heat exchangers. Users can choose the appropriate type of heat exchanger based on their operating conditions and needs. Located downstream of the economizer in the flue gas passage, the air preheater is integrated with other equipment in the boiler system and is suitable for boiler systems of various sizes and types. The flue gas outlet of the air preheater is connected to a dust collector. Before entering the atmosphere, the flue gas after heat exchange passes through the dust collector to remove particulate matter, meeting environmental emission standards and reducing environmental pollution. The heat exchange plates adopt a double-sided raised structure, which not only increases the heat exchange area but also improves the mechanical strength of the heat exchange plates, enabling them to withstand higher pressures and temperatures. Attached Figure Description

[0015] Figure 1 A schematic diagram of the structure of an air preheater for a high-efficiency heat recovery boiler;

[0016] Figure 2 A schematic diagram of a wide-channel plate heat exchanger;

[0017] The components in the diagram are named as follows: 1. Boiler; 2. Furnace; 3. Superheater; 4. Economizer; 5. Air preheater; 6. Steam drum; 7. Superheated steam output pipe; 8. Air inlet; 9. Dust collector; 10. Heat exchange core; 11. Heat exchange plate; 12. Inner channel; 13. Outer channel; 14. Weld joint; 15. Guide bar. Detailed Implementation

[0018] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention. Example 1

[0019] This example discloses a high-efficiency heat recovery type boiler air preheater. See [link to documentation]. Figures 1 to 2The boiler 1 includes a furnace 2 for generating high-temperature flue gas through fuel combustion. A superheater 3, an economizer 4, and at least one air preheater 5 are sequentially arranged at the outlet of the furnace 2 along the flue gas flow direction. The steam inlet end of the superheater 3 is connected to the outlet of the steam drum 6, and the outlet end of the superheater 3 is connected to the superheated steam output pipe 7. The lower part of the steam drum 6 is connected to the water-cooled wall of the furnace. The inlet of the steam drum 6 is connected to the economizer 4. The feed water inlet 5 of the economizer 4 is connected to a water source. The air preheater 5 is located in the flue gas passage downstream of the economizer 4. The air inlet 8 of the air preheater 5 is connected to a blower.

[0020] The air preheater 5 is a wide-channel plate heat exchanger, a tube heat exchanger, a rotary heat exchanger, or a heat pipe air heat exchanger.

[0021] It also includes a dust collector 9, and the flue gas outlet of the air preheater 5 is connected to the dust collector 9 to remove particulate matter from the flue gas before it is discharged.

[0022] The wide-channel plate heat exchanger includes a heat exchange core 10, which includes multiple heat exchange plates 11 arranged side by side. Each heat exchange plate 11 is a single plate welded together by multiple weld points 14 to form a double-sided raised structure. Between the two single plates is a corrugated wide-channel inner channel 12, and between adjacent heat exchange plates is an outer channel 13.

[0023] Solder points 14 are arranged in an interlaced grid pattern.

[0024] Multiple guide strips 15 are staggered on the heat exchange plate 11 along the flow direction of the fluid in its inner and / or outer channels, so that the fluid moves forward in an S-shaped circulation in the inner and / or outer channels.

[0025] The length of the guide bar 15 is less than the length of the heat exchange plate, and the number of guide bars 15 is odd.

[0026] During operation, high-temperature flue gas is generated in furnace 2 and carries a large amount of heat after fuel combustion. The flue gas flows out of the furnace 2 outlet, passing sequentially through heat exchanger 3 to generate superheated steam, economizer 4 to preheat boiler feedwater, and finally entering through the flue gas inlet of air preheater 5. After entering air preheater 5, the flue gas first flows into the inner channel 12 (corrugated wide-channel type channel) of heat exchange core 10. The inner channel 12 is formed by the double-sided convex structure of heat exchange plates 11, through which the flue gas flows. An outer channel 13 is formed between adjacent heat exchange plates 11, through which air passes. As the flue gas flows in the inner channel 12, its heat is transferred to the air in the outer channel 13 via the heat exchange plates 11. The double-sided convex structure and corrugated wide-channel design of the heat exchange plates 11 increase the contact area between the flue gas and the plates, improving heat transfer efficiency. Multiple guide strips 15 are provided on the heat exchange plates 11, which are staggered along the fluid flow direction. The guide strips 15 cause the flue gas and air to circulate forward along an S-shaped path within the channel, increasing the fluid residence time and heat exchange path, further improving heat exchange efficiency. Air is supplied by a blower and enters from the air inlet 8 of the air preheater 5. After entering the air preheater 5, the air flows into the outer channel 13. During the flow, the air absorbs heat transferred by the heat exchange plates 11, and its temperature gradually increases. The preheated air flows out from the air outlet of the air preheater 5, and its temperature has significantly increased. It is then sent to the boiler's combustion system for combustion support, thereby improving combustion efficiency. After heat exchange, the temperature of the flue gas decreases significantly. The cooled flue gas flows out from the flue gas outlet of the air preheater 5 and enters the dust collector 9, where particulate matter is removed. The flue gas after dust removal meets environmental emission standards and is finally discharged into the atmosphere through the chimney.

[0027] Although some preferred embodiments of the present invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the present invention.

[0028] Obviously, those skilled in the art can make various modifications and variations to this utility model without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this application and their equivalents, this utility model also intends to include these modifications and variations.

Claims

1. A high-efficiency heat recovery type boiler air preheater, characterized in that: The boiler includes a furnace for generating high-temperature flue gas through fuel combustion. A superheater, an economizer, and at least one air preheater are sequentially arranged at the furnace outlet along the flue gas flow direction. The steam inlet of the superheater is connected to the steam drum outlet, and the superheater outlet is connected to a superheated steam output pipe. The lower part of the steam drum is connected to the furnace water-cooled wall, and the steam drum inlet is connected to the economizer. The economizer feedwater inlet is connected to a water source. The air preheater is located downstream of the economizer in the flue gas passage, and the air inlet of the air preheater is connected to a blower.

2. The high-efficiency heat recovery type boiler air preheater as described in claim 1, characterized in that: The air preheater is a wide-channel plate heat exchanger, a tubular heat exchanger, a rotary heat exchanger, or a heat pipe air heat exchanger.

3. The high-efficiency heat recovery type boiler air preheater as described in claim 1, characterized in that: It also includes a dust collector, with the flue gas outlet of the air preheater connected to the dust collector to remove particulate matter from the flue gas before it is discharged.

4. The high-efficiency heat recovery type boiler air preheater as described in claim 2, characterized in that: The wide-channel plate heat exchanger includes a heat exchange core, which includes multiple heat exchange plates arranged side by side. Each heat exchange plate is a single plate welded together by multiple weld points to form a double-sided raised structure. There is a corrugated wide-channel inner channel between the two single plates, and an outer channel is formed between adjacent heat exchange plates.

5. The high-efficiency heat recovery type boiler air preheater as described in claim 4, characterized in that: The weld points are arranged in an alternating grid pattern.

6. The high-efficiency heat recovery type boiler air preheater as described in claim 4, characterized in that: Multiple guide strips are staggered on the heat exchange plates along the flow direction of the fluid in the inner and / or outer channels, so that the fluid moves forward in an S-shaped circulation within the inner and / or outer channels.

7. The high-efficiency heat recovery type boiler air preheater as described in claim 6, characterized in that: The length of the guide bar is less than the length of the heat exchange plate, and the number of the guide bars is an odd number.

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