Heat exchange plate and economizer

Abstract

The utility model relates to a heat exchange plate and a coal economizer, the heat exchange plate is used for being installed on the coal economizer to exchange heat with high-temperature flue gas, the heat exchange plate comprises a first plate body and a second plate body, and a first channel for heat exchange medium circulation is formed between the first plate body and the second plate body; the first plate body and the second plate body are respectively provided with a first side in contact with the high-temperature flue gas, and the surface of the first side of the first plate body and the surface of the first side of the second plate body are respectively provided with an anti-corrosion layer. By means of the technical scheme, the heat exchange structure of the economizer is arranged to be in the plate shape, so that the anti-corrosion layer is arranged on the side, close to high-temperature flue gas, of the heat exchange plate so as to reduce the possibility that when the flue gas temperature is lower than the dew point temperature, sulfuric acid steam in the flue gas is condensed and combined with water vapor to form sulfuric acid, and the heat exchange plate is corroded; and the durability of the heat exchange plate is improved.

Description

Technical Field

[0001] The present disclosure relates to the technical field of thermal power generation, and in particular to a heat exchange plate and an economizer. Background Art

[0002] Economizer is an important component in the boiler system. By installing an economizer, the thermal efficiency and economic benefits of the boiler system can be improved, while reducing energy consumption and environmental pollution.

[0003] In related technologies, when flue gas temperatures fall below the dew point, sulfuric acid vapor in the flue gas condenses and combines with water vapor to form sulfuric acid, causing corrosion of the economizer's finned tubes. Furthermore, corrosive gases such as sulfides and chlorides in the high-temperature flue gas react with metal surfaces, also causing corrosion of the economizer's finned tubes. Corroded finned tubes weaken the economizer's heat transfer performance, resulting in a decrease in thermal efficiency. This fails to achieve heat recovery, increases the power consumption of the induced draft fan, and can even lead to leakage, compromising the safety of the equipment. Utility Model Content

[0004] The purpose of the present disclosure is to provide a heat exchange plate and an economizer, wherein the heat exchange structure of the economizer is set to a plate shape and an anti-corrosion layer is provided on the side of the heat exchange plate in contact with the high-temperature flue gas, so as to at least partially solve the above technical problems.

[0005] In order to achieve the above-mentioned purpose, according to the first aspect of the present disclosure, a heat exchange plate is provided for being installed in an economizer to exchange heat with high-temperature flue gas. The heat exchange plate includes a first plate body and a second plate body, and a first channel for the circulation of heat exchange medium is formed between the first plate body and the second plate body. The first plate body and the second plate body both have a first side in contact with the high-temperature flue gas, and the surface of the first side of the first plate body and the surface of the first side of the second plate body are both provided with an anti-corrosion layer.

[0006] Optionally, the first plate body and the second plate body are both made of ND steel, and the anti-corrosion layer is constructed as an enamel plating process layer provided on the surface of the first side of the first plate body and the surface of the first side of the second plate body.

[0007] Optionally, the heat exchange plate includes a plurality of expansion portions arranged at intervals, and the first plate body and the second plate body both have a second side in contact with the heat exchange medium and opposite to the first side, and the first part of the second side of the first plate body and the first part of the second side of the second plate body are correspondingly opposed to form the expansion portion.

[0008] Optionally, the heat exchange plate includes a plurality of spaced apart fixing portions, the plurality of the fixing portions and the plurality of the expansion portions are spaced apart, and the second portion of the second side of the first plate body and the second portion of the second side of the second plate body are correspondingly close to or connected to form the fixing portion.

[0009] Optionally, the expansion portion includes an edge region and a middle region, the edge region is connected to the fixing portion, and the middle region is connected to the edge region, and the distance between the second side of the first plate body forming the middle region and the second side of the second plate body is greater than the distance between the second side of the first plate body forming the edge region and the second side of the second plate body.

[0010] Optionally, a distance d between the second side of the first plate body and the second side of the second plate body forming the middle area is 7 mm to 10 mm.

[0011] Optionally, an inlet connected to the first channel is formed on the first plate body and / or the second plate body, and the inlet is used to input heat exchange medium into the first channel. The first plate body and / or the second plate body are provided with an outlet connected to the first channel, and the outlet is used to discharge the heat exchange medium in the first channel.

[0012] According to a second aspect of the present disclosure, an economizer is provided, comprising the heat exchange plates as described above, wherein the heat exchange plates are provided in plural numbers and arranged at intervals, and a second channel for the high-temperature flue gas to flow is formed between two adjacent heat exchange plates.

[0013] Optionally, two adjacent heat exchange plates are staggered so that the fixed portion of one heat exchange plate corresponds to the expansion portion of the other heat exchange plate.

[0014] Optionally, the distance D between two adjacent heat exchange plates is 30 mm to 80 mm.

[0015] Through the above technical solution, the heat exchange plate is installed in the economizer for heat exchange with high-temperature flue gas. Compared with the finned tube in the related art, the heat exchange structure of the economizer is set to a plate shape in the present disclosure, so that an anti-corrosion layer is set on the side of the heat exchange plate close to the high-temperature flue gas. This is used to reduce the possibility of sulfuric acid vapor in the flue gas condensing and combining with water vapor to form sulfuric acid when the flue gas temperature is lower than the dew point temperature, thereby reducing the possibility of corrosion to the heat exchange plate. Specifically, the heat exchange plate includes a first plate body and a second plate body. The heat exchange medium flows in a first channel formed between the first plate body and the second plate body for heat exchange with the high-temperature flue gas. When the economizer is exemplarily applied to the heat exchanger, water is used as the heat exchange medium to exchange heat with the high-temperature flue gas, so that the waste heat in the high-temperature flue gas is used to preheat the water and serve as boiler feed water, thereby improving the thermal efficiency of the boiler.

[0016] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following detailed description, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0018] Figure 1 is a schematic diagram of a partial structure of a heat exchange plate provided in an exemplary embodiment of the present disclosure;

[0019] Figure 2 is a schematic diagram of the partial structure of two adjacent heat exchange plates provided in an exemplary embodiment of the present disclosure;

[0020] Figure 3 Schematic diagram of the combined structure of two adjacent heat exchange plates provided in an exemplary embodiment of the present disclosure.

[0021] Description of Reference Numerals

[0022] 1. First plate; 2. Second plate; 3. First channel; 4. Expansion portion; 41. Edge region; 42. Middle region; 5. Fixing portion; 6. Second channel. DETAILED DESCRIPTION

[0023] The following describes the specific embodiments of the present disclosure in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present disclosure and are not intended to limit the present disclosure.

[0024] In this disclosure, unless otherwise specified, "inside" and "outside" refer to the inside and outside of the corresponding component's outline; "far" and "near" refer to the spatial distance of the corresponding component relative to another component. Furthermore, the terms "first," "second," and so on, used in this disclosure, are intended to distinguish one element from another and do not convey sequential or significant meanings. In the following description, unless otherwise indicated, identical numerals in different figures represent identical or similar elements.

[0025] According to the first aspect of the present disclosure, referring to Figures 1 to 3 As shown, the present disclosure provides a heat exchange plate for installation in an economizer to exchange heat with high-temperature flue gas. The heat exchange plate includes a first plate body 1 and a second plate body 2. A first channel 3 for circulating a heat exchange medium is formed between the first plate body 1 and the second plate body 2. The first plate body 1 and the second plate body 2 both have a first side in contact with the high-temperature flue gas, and the surface of the first side of the first plate body 1 and the surface of the first side of the second plate body 2 are both provided with an anti-corrosion layer.

[0026] Through the above technical solution, the heat exchange plate is installed in the economizer for heat exchange with high-temperature flue gas. Compared with the finned tube in the related art, the heat exchange structure of the economizer is set to a plate shape in the present disclosure, so that an anti-corrosion layer is provided on the side of the heat exchange plate close to the high-temperature flue gas. This is used to reduce the possibility of sulfuric acid vapor in the flue gas condensing and combining with water vapor to form sulfuric acid when the flue gas temperature is lower than the dew point temperature, thereby reducing the possibility of corrosion of the heat exchange plate caused by sulfuric acid vapor in the flue gas condensing and combining with water vapor to form sulfuric acid, thereby improving the durability of the heat exchange plate. Specifically, the heat exchange plate includes a first plate body 1 and a second plate body 2. The heat exchange medium flows in a first channel 3 formed between the first plate body 1 and the second plate body 2 for heat exchange with the high-temperature flue gas. When the economizer is exemplarily applied to the heat exchanger, water is used as the heat exchange medium to exchange heat with the high-temperature flue gas, so that the waste heat in the high-temperature flue gas is used to preheat this part of water and serve as boiler feed water, thereby improving the thermal efficiency of the boiler.

[0027] In some exemplary embodiments, the first and second plates 1 and 2 can both be made of ND steel, with the anti-corrosion layer being a porcelain enamel coating applied to the first and second surfaces of the first and second plates 1 and 2. ND steel (weathering steel, also known as atmospheric corrosion-resistant steel) is a type of steel with excellent corrosion resistance. Specifically, by adding a certain proportion of alloying elements (such as Cu, Cr, Ni, and Mo), ND steel forms a dense and stable protective oxide layer on its surface, effectively slowing the corrosion rate of the steel. ND steel also exhibits excellent weldability, making it suitable for connecting the first and second plates 1 and 2, i.e., forming the fixing portion 5 (described later).

[0028] Vitreous enameling (also known as porcelain enamel or enamelling) involves melting a glassy material and applying it to a metal surface. The enameled surface offers excellent corrosion resistance, resisting acid and alkali attack and rusting. It also boasts excellent heat resistance, allowing it to withstand high temperatures without deformation. Furthermore, the smooth, even surface of the enameled plate prevents dust from accumulating, enabling it to self-clean.

[0029] It is understood that in some other possible alternative embodiments not shown in the drawings, the material of the first plate 1 and the second plate 2 can also be set to stainless steel, and the anti-corrosion layer is a dense oxide film spontaneously formed on the surface of the stainless steel, which can effectively prevent further corrosion reactions. The present disclosure is not limited to this.

[0030] In some embodiments, reference Figures 1 to 3As shown, the heat exchange plate can include multiple expansion portions 4 spaced apart. The first plate 1 and the second plate 2 each have a second side that contacts the heat exchange medium and is opposite the first side. The first portion of the second side of the first plate 1 and the first portion of the second side of the second plate 2 are aligned with each other to form the expansion portion 4. Thus, the provision of the expansion portion 4 increases the flow volume of the first channel 3, increasing the amount of heat exchange medium within the first channel 3 and thereby improving the heat exchange capacity between the heat exchange plate and the high-temperature flue gas. Furthermore, the provision of the expansion portion 4 increases the heat exchange area between the first plate 1 and the second plate 2, allowing the heat exchange medium flowing within the first channel 3 to fully exchange heat with the high-temperature flue gas, thereby improving the heat exchange capacity of the heat exchange plate.

[0031] In some embodiments, reference Figure 1 and Figure 2 As shown, the heat exchange plate may include multiple spaced fixing portions 5. The multiple fixing portions 5 and the multiple expansion portions 4 are arranged at intervals. The second portion of the second side of the first plate body 1 and the second portion of the second side of the second plate body 2 are correspondingly close to or connected to form the fixing portions 5. Thus, by providing the fixing portions 5, the heat exchange area between the first plate body 1 and the second plate body 2 can be increased, allowing the heat exchange medium flowing in the first channel 3 to fully exchange heat with the high-temperature flue gas, thereby further improving the heat exchange capacity of the heat exchange plate.

[0032] It is understandable that the expansion portion 4 and the fixing portion 5 can be formed in a variety of ways. For example, the present disclosure uses laser oxygen-free welding technology to weld the second part of the second side of the first plate 1 and the second part of the second side of the second plate 2 together to form the fixing portion 5. In this way, laser oxygen-free welding can achieve very precise energy control, ensuring uniform temperature and energy distribution in the welding area, thereby improving the connection strength of the first plate 1 and the second plate 2 and ensuring the normal heat exchange function of the heat exchange plate. Then, the first part of the second side of the first plate 1 and the first part of the second side of the second plate 2 are hydraulically expanded to form the expansion portion 4. At this time, the first plate 1 and the second plate 2 are constructed to be similar to a wavy plate. The peak position of the first plate 1 constructed as a wavy plate is the expansion portion 4, and the trough position is the fixing portion 5. The peak position of the second plate 2 constructed as a wavy plate is the fixing portion 5, and the trough position is the expansion portion 4.

[0033] By providing the expansion portion 4 and the fixing portion 5, the shape of the heat exchange plate can be changed, thereby creating turbulence in the fluids (i.e., the heat exchange medium and the high-temperature flue gas) inside and outside the heat exchange plate, thereby achieving efficient heat exchange. Therefore, when the heat exchange plate is exemplarily applied to an economizer, higher temperature preheated water can be obtained from the heat exchange plate to reduce the heating energy consumption of the boiler feed water and achieve better energy saving.

[0034] In some embodiments, reference Figure 1 and Figure 2As shown, the expansion portion 4 may include an edge region 41 and a middle region 42, the edge region 41 being connected to the fixing portion 5, and the middle region 42 being connected to the edge region 41, and the distance between the second side of the first plate body 1 and the second side of the second plate body 2 forming the middle region 42 is greater than the distance between the second side of the first plate body 1 and the second side of the second plate body 2 forming the edge region 41. In this way, the fixing portion 5 and the expansion portion 4 are arranged at intervals, the edge region 41 is located at the circumferential edge of the expansion portion 4, and the middle region 42 is connected to the edge region 41 and is located in the middle of the expansion portion 4. The present disclosure exemplarily constructs the cross-section of the expansion portion 4 into a wavy shape, that is, the distance between the second side of the first plate body 1 and the second side of the second plate body 2 gradually increases when transitioning from the edge region 41 to the middle region 42. Therefore, the first side of the first plate body 1 and the first side of the second plate body 2 are both smoothly curved, and there is no high-temperature flue gas dead zone. The surface of the first side of the first plate body 1 and the surface of the first side of the second plate body 2 are not easy to accumulate dust. Under the appropriate high-temperature flue gas flow rate, the heat exchange plate has a good self-cleaning function, so that the deposited dust can be self-cleaned.

[0035] In some exemplary embodiments, referring to Figures 1 to 3 As shown, the distance d between the second side of the first plate 1 and the second side of the second plate 2, which form the middle region 42, can be 7 mm to 10 mm. Thus, the maximum cross-sectional height of the first channel 3 can be 7 mm to 10 mm, thereby increasing the flow volume of the first channel 3, ensuring the normal flow of the heat exchange medium within the first channel 3, and increasing the amount of heat exchange medium within the first channel 3, thereby improving the heat exchange capacity between the heat exchange plate and the high-temperature flue gas. It is also understood that when this heat exchange plate is exemplarily applied to an economizer, the number of heat exchange plates can be set to multiple to improve the overall heat exchange capacity of the heat exchanger. The distance d between the second side of the first plate 1 and the second side of the second plate 2 in the middle region 42 needs to meet the installation requirements of multiple heat exchange plates.

[0036] In some exemplary embodiments, the first plate 1 and / or the second plate 2 may be provided with an inlet connected to the first channel 3, for inputting a heat exchange medium into the first channel 3. The first plate 1 and / or the second plate 2 may be provided with an outlet connected to the first channel 3, for discharging the heat exchange medium from the first channel 3. In the present disclosure, the inlet is exemplarily provided on the first plate 1 and the outlet is provided on the second plate 2, and the inlet and outlet are located on opposite sides of the heat exchange plate. That is, the inlet may be provided on one side of the heat exchange plate, and the outlet may be provided on the other side of the heat exchange plate opposite the side provided with the inlet. In this way, the heat exchange medium is input into the first channel 3 from the inlet, and circulates in the first channel 3 to exchange heat with the high-temperature flue gas, and then the heat exchange medium with a higher temperature after heat exchange is discharged from the first channel 3 through the outlet. The flow distance and flow time of the heat exchange medium in the first channel 3 are longer, so as to improve the heat exchange capacity of the heat exchange plate and the temperature of the heat exchange medium. When the heat exchange plate is applied to an economizer, for example, the heat exchange medium, i.e., boiler feed water, has a higher temperature when discharged through the outlet, so as to reduce the energy consumption of boiler feed water preheating and effectively save energy.

[0037] In some other possible alternative embodiments, the inlet and outlet may also be both arranged on the second plate body 2, or the inlet and outlet may also be respectively arranged on the first plate body 1 and the second plate body 2. At the same time, the positions of the inlet and outlet on the first plate body 1 and the second plate body 2 may also be determined according to actual needs, and the present disclosure does not make specific limitations on this.

[0038] According to a second aspect of the present disclosure, an economizer is provided, comprising the aforementioned heat exchange plates. The heat exchange plates are provided in a plurality and arranged in an interval, with a second channel 6 formed between adjacent heat exchange plates for the circulation of high-temperature flue gas. The high-temperature flue gas circulates within the second channel 6 to exchange heat with the heat exchange medium flowing within the first channel 3. The economizer can thus utilize the waste heat in the high-temperature flue gas to preheat boiler feed water, i.e., the aforementioned heat exchange medium. As the high-temperature flue gas passes through the economizer, the heat therein is transferred to the boiler feed water, raising the boiler feed water temperature and reducing the energy consumption for preheating the boiler feed water, thereby improving the boiler's thermal efficiency. Furthermore, by recovering the heat from the high-temperature flue gas, heat waste is reduced, which also helps to reduce environmental pollution.

[0039] In some embodiments, reference Figure 3 As shown, two adjacent heat exchange plates can be staggered so that the fixed portion 5 of one heat exchange plate corresponds to the expansion portion 4 of the other. Thus, compared to the finned tubes used in related art, the heat exchange structure of the economizer disclosed herein is constructed using multiple plate-shaped heat exchange plates. A straight-through channel is formed between adjacent heat exchange plates. This prevents cross-flow of high-temperature flue gas in the second channel 6 when it flows horizontally. Furthermore, the vortex flow on the leeward side of the heat exchange tubes, a common problem in finned tube economizers, is eliminated, thereby improving the heat exchange efficiency of the high-temperature flue gas.

[0040] In some other possible alternative embodiments not shown in the accompanying drawings, two adjacent heat exchange plates may also be arranged correspondingly, or partially staggered. Similarly, a high-temperature flue gas direct current channel may be formed between two adjacent heat exchange plates to enable the high-temperature flue gas to fully exchange heat with the heat exchange medium. The present disclosure does not make specific limitations on this.

[0041] In some embodiments, reference Figure 2 and Figure 3 As shown, the distance D between adjacent heat exchange plates can range from 30mm to 80mm. This ensures the flow of high-temperature flue gas while minimizing the possibility of lateral cross-flow, enabling sufficient heat exchange between the high-temperature flue gas and the heat exchange medium, thereby preheating the heat exchange medium, namely, the boiler feed water. Furthermore, the economizer includes multiple heat exchange plates spaced apart, with appropriate spacing between them to ensure proper installation and, consequently, the proper heat exchange function of the economizer.

[0042] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings. However, the present disclosure is not limited to the specific details of the above embodiments. Within the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all fall within the scope of protection of the present disclosure.

[0043] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0044] In addition, the various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A heat exchange plate, used for installation in an economizer to exchange heat with high-temperature flue gas, characterized in that: The heat exchange plate includes a first plate body and a second plate body, a first channel for circulating a heat exchange medium is formed between the first plate body and the second plate body, the first plate body and the second plate body both have a first side in contact with the high-temperature flue gas, and the surface of the first side of the first plate body and the surface of the first side of the second plate body are both provided with an anti-corrosion layer.

2. The heat exchange plate according to claim 1, characterized in that The first plate body and the second plate body are both made of ND steel, and the anti-corrosion layer is constructed as an enamel coating layer provided on the surface of the first side of the first plate body and the surface of the first side of the second plate body.

3. The heat exchange plate according to claim 1, characterized in that The heat exchange plate includes a plurality of expansion portions arranged at intervals. The first plate body and the second plate body both have a second side that contacts the heat exchange medium and is opposite to the first side. The first portion of the second side of the first plate body and the first portion of the second side of the second plate body are correspondingly opposed to each other to form the expansion portion.

4. The heat exchange plate according to claim 3, characterized in that The heat exchange plate includes a plurality of spaced apart fixing portions, the plurality of the fixing portions and the plurality of the expansion portions are spaced apart, and the second portion of the second side of the first plate body and the second portion of the second side of the second plate body are correspondingly close to or connected to form the fixing portions.

5. The heat exchange plate according to claim 4, characterized in that: The expansion portion includes an edge region and a middle region, the edge region is connected to the fixing portion, and the middle region is connected to the edge region, and the distance between the second side of the first plate body and the second side of the second plate body forming the middle region is greater than the distance between the second side of the first plate body and the second side of the second plate body forming the edge region.

6. The heat exchange plate according to claim 5, characterized in that: A distance d between the second side of the first plate and the second side of the second plate forming the middle area is 7 mm to 10 mm.

7. The heat exchange plate according to claim 1, characterized in that The first plate body and / or the second plate body is provided with an inlet connected to the first channel, and the inlet is used to input heat exchange medium into the first channel. The first plate body and / or the second plate body is provided with an outlet connected to the first channel, and the outlet is used to discharge the heat exchange medium in the first channel.

8. An economizer, characterized in that: The heat exchange plate comprises the heat exchange plate according to any one of claims 1 to 7, wherein the number of the heat exchange plates is set to be multiple and arranged at intervals, and a second channel for the high-temperature flue gas to flow is formed between two adjacent heat exchange plates.

9. The economizer according to claim 8, characterized in that: The two adjacent heat exchange plates are staggered so that the fixed portion of one heat exchange plate corresponds to the expansion portion of the other heat exchange plate.

10. The economizer according to claim 8, characterized in that: The distance D between two adjacent heat exchange plates is 30 mm to 80 mm.

Images