A thermal recovery and reuse system and method for wet desulfurization tail gas

Abstract

The present invention relates to the technical field of desulfurization. Specifically, it relates to a heat recovery and reuse system and method for wet desulfurization tail gas. The system includes a cooling and condensation tower and an air preheating tower, and the cooling and condensation tower and the air preheating tower are respectively provided with an air inlet and an air outlet; a condensation spraying device is fixedly installed in the cooling and condensation tower, and a preheating spraying device is fixedly installed in the air preheating tower; the condensation spraying device includes at least one spraying layer, and each spraying layer is communicated with the air preheating tower through a pipeline; the preheating spraying device includes at least one spraying layer, and each spraying layer is communicated with the cooling and condensation tower through a pipeline. This system can recover the heat in the desulfurization tail gas, prevent the generation of "white smoke" after discharge; the recovered heat can be used to preheat the boiler, saving energy; the spraying device can also. The flushing of the low-temperature circulating water can also remove pollutants such as residual SO2, NO2, and desulfurization slurry dust in the flue gas, achieving deep purification.

Description

Technical Field

[0001] The present invention relates to the technical field of desulfurization, and more specifically, to a thermal recovery and reuse system and method for wet desulfurization tail gas. Background Art

[0002] With the further development of urbanization, the urban central heating area will further increase, and the total heating volume will inevitably rise; with the in-depth work of CO2 emission reduction requirements, the newly built units of coal-fired heating projects in cities will inevitably decrease; the difference in the total heating volume generated between the two will inevitably bring the demand for low-temperature waste heat recovery technology and the development of the application market. Therefore, low-temperature waste heat recovery will surely become an important development direction in the market.

[0003] The limestone-gypsum wet desulfurization technology is the most widely used and mature flue gas desulfurization process, and its flue gas discharge temperature is generally between 50 and 60 °C. Due to the relatively low ambient temperature, when discharging the desulfurized flue gas, the large temperature difference will cause the water vapor in the flue gas to quickly condense, resulting in a large amount of white smoke emerging from the chimney outlet, causing visual pollution.

[0004] In addition, the direct discharge of the heat in the desulfurization tail gas will cause waste of heat energy. Therefore, directly discharging the desulfurized tail gas not only does not meet the requirements of environmental protection and green development, but also causes waste of heat, and at the same time, it will also cause visual pollution. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a thermal recovery and reuse system and method for wet desulfurization tail gas.

[0006] The technical solution of the present invention for solving the above technical problem is as follows:

[0007] The present invention provides a thermal recovery and reuse system for wet desulfurization tail gas, including a cooling and condensation tower and an air preheating tower. The cooling and condensation tower and the air preheating tower are respectively provided with an air inlet and an air outlet; a condensation spraying device is fixedly installed in the cooling and condensation tower, and a preheating spraying device is fixedly installed in the air preheating tower; the condensation spraying device includes at least one spraying layer, and each spraying layer is communicated with the air preheating tower through a pipeline; the preheating spraying device includes at least one spraying layer, and each spraying layer is communicated with the cooling and condensation tower through a pipeline.

[0008] The beneficial effects of the above technical solution of the present invention are as follows: By providing a cooling and condensation tower and an air preheating tower that are interconnected, heat exchange can be performed on the wet flue gas desulfurization tail gas and the ambient air used for heat recovery respectively, so as to recover the heat in the wet flue gas desulfurization tail gas and prevent the generation of "white smoke" after its discharge, causing visual pollution; The heated ambient air can be used for preheating the boiler, saving energy; By providing a condensation spraying device, a preheating spraying device and a connected pipeline, the cooling water can be circulated between the cooling and condensation tower and the air preheating tower, saving the amount of cooling water used.

[0009] The present invention can also be realized by the following further technical solutions:

[0010] Furthermore, a first air inlet is provided on the side wall of the cooling and condensation tower, and a first air outlet is provided at the top. The condensation spraying device is located between the first air inlet and the first air outlet in the vertical direction; A second air inlet is provided on the side wall of the air preheating tower, and a second air outlet is provided at the top; The preheating spraying device is located between the second air inlet and the second air outlet in the vertical direction.

[0011] The beneficial effects of adopting the above further technical solution are as follows: By arranging the condensation spraying device between the first air inlet and the first air outlet, the downwardly sprayed low-temperature circulating water and the upwardly moving tail gas can have a sufficiently large contact area and contact time, which can extend the heat exchange process and enable full heat exchange between the tail gas and the cooling, improving the efficiency of heat recovery; The effect of the preheating spraying device is the same as the above.

[0012] Furthermore, the position where each spraying layer of the condensation spraying device communicates with the air preheating tower is located below the second air inlet; The position where each spraying layer of the preheating spraying device communicates with the cooling and condensation tower is located below the first air inlet.

[0013] The beneficial effects of adopting the above further technical solution are as follows: After the low-temperature circulating water or high-temperature circulating water sprayed by the spraying layer falls to the bottom of the cooling and condensation tower or the air preheating tower, it can quickly flow out and circulate, preventing the excessive retention of the circulating water at the bottom of the cooling and condensation tower or the air preheating tower; This can improve the circulation efficiency of the circulating water and reduce the total amount of circulating water used.

[0014] Furthermore, a demister is fixedly installed on the cooling and condensation tower, and the demister is located above the condensation spraying device in the vertical direction.

[0015] The beneficial effects of adopting the above further technical solution are as follows: By providing a demister, the liquid droplets contained in the heat-exchanged desulfurization tail gas can be removed before it is discharged from the first air outlet, further avoiding the generation of "white smoke" composed of water vapor after discharge.

[0016] Further, a circulating spray device is fixedly installed inside the air preheating tower, and the circulating spray device is located above the preheating spray device in the vertical direction; an external circulating pipeline is provided for the air preheating tower, an inlet of the circulating pipeline is communicated with the lower part of the air preheating tower, and an outlet of the circulating pipeline is communicated with the circulating spray device.

[0017] The beneficial effect of adopting the above further technical solution is that the self-circulation of low-temperature circulating water inside the air preheating tower can be realized.

[0018] Further, valves and discharge pumps are provided on the pipelines connected to each of the spray layers, and the discharge pumps are close to the spray layers communicated with the pipelines, and the valves are far away from the spray layers communicated with the pipelines.

[0019] The beneficial effect of adopting the above further technical solution is that the independent control of each spray layer can be realized.

[0020] Further, an external discharge pipeline is also communicated with the lower part of the air preheating tower.

[0021] The beneficial effect of adopting the above further technical solution is that it is convenient to discharge the circulating water.

[0022] The present invention provides a method for heat recovery and reuse of wet desulfurization tail gas. The above system is adopted for heat recovery and reuse, and the heat of the wet desulfurization tail gas is transferred to the air for heat recovery through the first heat exchange process carried out inside the cooling and condensation tower and the second heat exchange process inside the air preheating tower by means of circulating water.

[0023] The beneficial effect of this method is that not only can the heat in the wet desulfurization tail gas be recovered again, but also the recovered heat can be exchanged to the air, and the high-temperature air absorbing the heat can be used in other systems or processes that need heating. For example, the high-temperature air can be introduced into a boiler and used for preheating the boiler, which can save energy and has the advantage of reducing production costs.

[0024] Further, the first heat exchange process is as follows: desulfurization tail gas is introduced into the cooling and condensation tower through the air inlet on the cooling and condensation tower, and at the same time, the condensation spray device sprays low-temperature circulating water, so that the low-temperature circulating water exchanges heat with the desulfurization tail gas and is converted into high-temperature circulating water; the second heat exchange process is as follows: air is introduced into the air preheating tower through the air inlet on the air preheating tower, and at the same time, the high-temperature circulating water circulates through the pipeline to the preheating spray device and is sprayed into the air preheating tower, so that the high-temperature circulating water exchanges heat with the air and is converted into low-temperature circulating water; after the circulating water completes one cycle through the first heat exchange process and the second heat exchange process, the next cycle is carried out.

[0025] Further, the temperature of the circulating water at low temperature is lower than the temperature of the desulfurized tail gas introduced into the cooling and condensation tower; the temperature of the circulating water at high temperature is higher than the temperature of the air introduced into the air preheating tower. Description of the Drawings

[0026] Figure 1 It is a schematic structural diagram of the heat recovery and reuse system for wet desulfurized tail gas of the present invention.

[0027] In the drawings, the list of components represented by each reference numeral is as follows:

[0028] 1. Cooling and condensation tower; 2. Air preheating tower; 3. First air inlet; 4. Condensing spray device; 5. Demister; 6. First discharge pump; 7. Second discharge pump; 8. Third discharge pump; 9. Fourth discharge pump; 10. Second air inlet; 11. Preheating spray device; 12. Circulating spray device; 13. First air outlet; 14. Second air outlet; 15. Circulating pipeline; 16. External discharge pipeline. Detailed Embodiments

[0029] The principles and features of the present invention will be described below with reference to the drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0030] As Figure 1 shown, the heat recovery and reuse system for wet desulfurized tail gas of the present invention includes a cooling and condensation tower 1 and an air preheating tower 2. The cooling and condensation tower 1 and the air preheating tower 2 are respectively provided with an air inlet and an air outlet; a condensing spray device 4 is fixedly installed in the cooling and condensation tower 1, and a preheating spray device 11 is fixedly installed in the air preheating tower 2; the condensing spray device 4 includes at least one spray layer, and each spray layer is communicated with the air preheating tower 2 through a pipeline; the preheating spray device 11 includes at least one spray layer, and each spray layer is communicated with the cooling and condensation tower 1 through a pipeline.

[0031] In the heat recovery and reuse system of the present invention, by providing the cooling and condensation tower 1 and the air preheating tower 2 that are interconnected, heat exchange can be respectively performed on the wet desulfurized tail gas and the ambient air for heat recovery, so as to recover the heat in the wet desulfurized tail gas and enable the heated ambient air to be reused; by providing the condensing spray device 4, the preheating spray device 11 and the connected pipelines, the cooling water can be circulated between the cooling and condensation tower 1 and the air preheating tower 2, saving the amount of cooling water used.

[0032] In addition, after the wet flue gas desulfurization tail gas is treated by the heat recovery and reuse system of the present invention, when the desulfurized tail gas is discharged to the outside, it is mixed with the outside air, and the situation of humidity supersaturation basically does not occur, so water vapor will not condense, that is, the "white plume" phenomenon will not occur. At the same time, in the cooling and condensation tower 1, the low-temperature circulating water sprays the desulfurized tail gas, so that the remaining pollutants such as SO2, NO2, and desulfurized slurry dust in it can be further removed, realizing the deep purification function.

[0033] In the above embodiment, preferably, the side wall of the cooling and condensation tower 1 is provided with a first air inlet 3, and the top is provided with a first air outlet 13. The condensation spraying device 4 is located between the first air inlet 3 and the first air outlet 13 in the vertical direction; the side wall of the air preheating tower 2 is provided with a second air inlet 10, and the top is provided with a second air outlet 14; the preheating spraying device 11 is located between the second air inlet 10 and the second air outlet 14 in the vertical direction; setting the first air inlet 3 on the side wall of the cooling and condensation tower 1 can facilitate the introduction of the wet flue gas desulfurization tail gas into the cooling and condensation tower 1. Setting the first air outlet 13 on the top of the cooling and condensation tower 1 can make the tail gas flow from bottom to top; setting the condensation spraying device 4 between the first air inlet 3 and the first air outlet 13 can make the downwardly sprayed low-temperature circulating water and the upwardly moving tail gas have a large enough contact area and contact time, which can extend the heat exchange process and enable the tail gas and the cooling to fully exchange heat, improving the heat recovery efficiency. For the position settings of the air preheating tower 2, the second air inlet 10, the second air outlet 14, and the preheating spraying device 11, their advantages are the same as those of the components in the above cooling and condensation tower 1.

[0034] In the above embodiment, preferably, the position where each spraying layer of the condensation spraying device 4 communicates with the air preheating tower 2 is located below the second air inlet 10; the position where each spraying layer of the preheating spraying device 11 communicates with the cooling and condensation tower 1 is located below the first air inlet 3; in this way, after the low-temperature circulating water or high-temperature circulating water sprayed by the spraying layer falls to the bottom of the cooling and condensation tower 1 or the air preheating tower 2, it can quickly flow out and circulate, preventing the excessive retention of the circulating water at the bottom of the cooling and condensation tower 1 or the air preheating tower 2; this can improve the circulation efficiency of the circulating water and reduce the total amount of circulating water used.

[0035] In addition, the circulating water actually exchanges heat with the outside world all the time during the circulating process. If the high-temperature circulating water after absorbing heat stays in the cooling and condensation tower 1 for a long time, part of the heat in the high-temperature circulating water will be released back into the cooling and condensation tower 1, and may even recombine with the desulfurized tail gas, resulting in a reduction in the heat recovery rate of the desulfurized tail gas; if the low-temperature circulating water stays in the air preheating tower 2 for a long time, it may reabsorb some heat, resulting in a poor effect when it circulates back to the cooling and condensation tower 1 to cool the desulfurized tail gas again.

[0036] In the above embodiments, preferably, the condensation spraying device 4 and the preheating spraying device 11 may each have a plurality of spraying layers, and the plurality of spraying layers are arranged in a stacked manner up and down; setting a plurality of spraying layers can further improve the heat exchange effect, so that the heat in the desulfurized tail gas can be recovered more thoroughly.

[0037] In the above embodiments, preferably, the first air inlet 3 and the second air inlet 10 are respectively connected to an air inlet pipe, and both air inlet pipes are arranged obliquely upward; by setting the inclined air inlet pipes, when the desulfurized tail gas and ambient air are respectively introduced into the cooling condensation tower 1 and the air preheating tower 2, they can first flow downward for a certain distance, which can further increase the contact time and contact area between the desulfurized tail gas and ambient air and the sprayed circulating water, thereby further improving the heat exchange efficiency and speed.

[0038] In the above embodiments, preferably, the cooling condensation tower 1 is fixedly installed with a demister 5, and the demister 5 is located above the condensation spraying device 4 in the vertical direction; by setting the demister 5, the liquid droplets contained in the desulfurized tail gas after heat exchange can be removed before being discharged from the first air outlet 13, further avoiding the generation of "white smoke" composed of water vapor after discharge.

[0039] In the above embodiments, preferably, a circulating spraying device 12 is fixedly installed in the air preheating tower 2, and the circulating spraying device 12 is located above the preheating spraying device 11 in the vertical direction; a circulating pipeline 15 is provided outside the air preheating tower 2, the liquid inlet of the circulating pipeline 15 is connected to the lower part of the air preheating tower 2, and the liquid outlet of the circulating pipeline 15 is connected to the circulating spraying device 12; by setting the circulating spraying device 12 and the circulating pipeline 15, the low-temperature circulating water after heat exchange can be circulated for heat exchange again, improving the absorption rate of the heat in the circulating water by the ambient air and making the heat recovery more complete.

[0040] Theoretically, some components such as the circulating pipeline 15 and the circulating spraying device 12 can also be set in the cooling condensation tower 1 to make the circulating water in it circulate by itself; however, in actual use, it is found through experiments that when heat exchange occurs in the air preheating tower 2, the circulating water releases heat to the ambient air, and the temperature of the circulating water decreases. When the low-temperature circulating water circulates by itself through the circulating pipeline 15 and the circulating spraying device 12, the continuously introduced low-temperature ambient air can continuously reduce its temperature, making the effect of setting the self-circulation device significant; however, when heat exchange occurs in the cooling condensation tower 1, the circulating water absorbs the heat in the desulfurized tail gas and the temperature rises from low. Circulating the circulating water with increased temperature again to continuously absorb the continuously introduced high-temperature desulfurized tail gas, the effect of heat recovery is not obvious; therefore, in order to make the system device structure simple, only the circulating pipeline 15 and the circulating spraying device 12 are set on the air preheating tower 2.

[0041] In the above embodiments, preferably, valves and discharge pumps are provided on the pipelines connected to each spraying layer, and the discharge pumps are close to the spraying layer connected to the pipeline, while the valves are far from the spraying layer connected to the pipeline; by providing independent valves and discharge pumps on each connected pipeline, each spraying layer can be independently controlled, making the system more flexible.

[0042] In the above embodiments, preferably, the lower part of the air preheating tower 2 is also connected to an external discharge pipeline 16, and the external discharge pipeline 16 is connected to a circulating water recovery device; by providing the external discharge pipeline 16, it is convenient to clean and recover the residual circulating water in the air preheating tower 2.

[0043] The method for heat recovery and reuse of the wet desulfurization tail gas of the present invention uses the above system for heat recovery and reuse, and transfers the heat of the wet desulfurization tail gas to the air for recovering heat through two heat exchange processes.

[0044] By using the method for heat recovery and reuse of the wet desulfurization tail gas of the present invention, not only can the heat in the wet desulfurization tail gas be recovered again, but also the recovered heat can be exchanged to the air, and the high-temperature air absorbing the heat can be used in other systems or processes that need heating. For example, the high-temperature air can be introduced into a boiler for preheating the boiler, which can save energy and has the advantage of reducing production costs.

[0045] In addition, after the heat-exchanged desulfurization tail gas is discharged into the external environment, since its temperature has decreased, it can prevent the appearance of "white smoke" to a certain extent, thereby preventing visual pollution.

[0046] Among them, the first heat exchange is that desulfurization tail gas is introduced into the cooling condensation tower 1 through the air inlet, and at the same time, the condensation spraying device 4 sprays low-temperature circulating water, so that the low-temperature circulating water exchanges heat with the desulfurization tail gas and is converted into high-temperature circulating water; the second heat exchange is that air is introduced into the air preheating tower 2 through the air inlet, and at the same time, the high-temperature circulating water circulates to the preheating spraying device 11 and is sprayed into the air preheating tower 2, so that the high-temperature circulating water exchanges heat with the air and is converted into low-temperature circulating water; after the second heat exchange, the low-temperature circulating water circulates back to the cooling condensation tower 1 again to repeat the first heat exchange.

[0047] The temperature of the low-temperature circulating water is lower than the temperature of the desulfurization tail gas introduced into the cooling condensation tower 1; the temperature of the high-temperature circulating water is higher than the temperature of the air introduced into the air preheating tower 2.

[0048] It should be noted that in the initial state, since there is no circulating water in the system, a certain amount of circulating water needs to be introduced first to start the above-mentioned heat exchange circulation process.

[0049] Since the system is not connected to the desulfurized tail gas or ambient air at the starting state, theoretically, low-temperature circulating water can be added to the cooling condensation tower 1 or the air preheating tower 2 through any opening. After low-temperature circulating water exists in the system, the heat exchange and circulation of the low-temperature circulating water can be realized by the power provided by each discharge pump.

[0050] Preferably, at the start, a certain amount of low-temperature circulating water can be first introduced through the second air inlet 10. After introduction, the discharge pump on the pipeline connected to the condensation spraying device 4 is turned on, and at the same time, the desulfurized tail gas to be heat-exchanged is introduced through the first air inlet 3 to realize the first heat exchange in the cooling condensation tower 1.

[0051] After the introduction of the low-temperature circulating water is completed, the second air inlet 10 can be connected to the ambient air to prepare for the heat exchange process in the air preheating tower 2.

[0052] The technical solution of the present invention is illustrated by the following specific embodiments:

[0053] Embodiment 1

[0054] As Figure 1 shown, in the heat recovery and reuse system of the wet desulfurized tail gas in this embodiment, the condensation spraying device 4 includes a spraying layer, and the preheating spraying device 11 also includes a spraying layer.

[0055] In addition to the components and devices already described above, it further includes a first discharge pump 6, a second discharge pump 7, a third discharge pump 8, and a fourth discharge pump 9; the first discharge pump 6 is installed on the pipeline connecting the preheating spraying device 11 and the cooling condensation tower 1, and a valve is also provided on this pipeline and the valve is close to the cooling condensation tower 1; the second discharge pump 7 is installed on the pipeline connecting the condensation spraying device 4 and the air preheating tower 2, and a valve is also provided on this pipeline and the valve is close to the air preheating tower 2; the third discharge pump 8 is installed on the circulating pipeline 15, and a valve is also provided on this pipeline and the valve is close to the bottom of the air preheating tower 2; the fourth discharge pump 9 is installed on the external discharge pipeline 16, and a valve is also provided on this pipeline and the valve is close to the air preheating tower 2.

[0056] In this embodiment, all connections between each pipeline and each valve, between each pipeline and each discharge pump, and between each pipeline and each spraying layer are made by flanges.

[0057] The working process of this embodiment is as follows:

[0058] At the start, a certain amount of low-temperature circulating water is first introduced through the second air inlet 10. When the low-temperature circulating water reaches the set liquid level, the second discharge pump 7 is turned on, and at the same time, the desulfurized tail gas to be heat-exchanged is introduced through the first air inlet 3.

[0059] The condensation spraying device 4 sprays low-temperature circulating water, enabling the low-temperature circulating water to exchange heat with the desulfurized tail gas and convert into high-temperature circulating water; the desulfurized tail gas after heat exchange is discharged to the outside of the system through the first air outlet 13.

[0060] When the high-temperature circulating water reaches the set liquid level, the first discharge pump 6 is turned on, causing the high-temperature circulating water to circulate to the preheating spraying device 11 and be sprayed into the air preheating tower 2. At the same time, air is introduced into the air preheating tower 2 through the second air inlet 10, enabling the high-temperature circulating water to exchange heat with the air and convert into low-temperature circulating water; the air after heat exchange is discharged through the second air outlet 14 and introduced into the boiler system for preheating the boiler.

[0061] The low-temperature circulating water circulates back to the cooling condensation tower 1 again to repeat the first heat exchange.

[0062] During the above process, when the high-temperature circulating water exchanges heat with the air, the third discharge pump 8 can be turned on simultaneously, causing a part of the low-temperature circulating water to self-circulate in the air preheating tower 2 through the circulation pipeline 15 and the circulation spraying device 12.

[0063] In this embodiment, the temperature of the low-temperature circulating water is lower than the temperature of the desulfurized tail gas introduced into the cooling condensation tower 1; the temperature of the high-temperature circulating water is higher than the temperature of the air introduced into the air preheating tower 2. Among them, the temperature of the introduced desulfurized tail gas is 50 - 60 °C, the temperature of the introduced air is 0 - 10 °C, the temperature of the heat exchange area in the cooling condensation tower 1 is 30 - 45 °C, and the temperature of the heat exchange area in the air preheating tower 2 is 25 - 40 °C.

[0064] After the system of this embodiment is used to recover the heat in the wet desulfurized tail gas, there is no "white plume" phenomenon when the tail gas is discharged. And through detection, the contents of pollutants such as SO2, NO2, and desulfurized slurry dust in the tail gas are lower than those of the tail gas without being treated by this system, indicating that the deep purification function is achieved.

[0065] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0066] In addition, 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 quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0067] In the present invention, unless otherwise clearly specified and defined, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher level height than the second feature. The first feature being "under", "beneath" and "underneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower level height than the second feature.

[0068] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0069] In the description of the present invention, it should be noted that, unless otherwise clearly specified and defined, the terms "mounted", "connected" and "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention may be understood according to specific circumstances.

[0070] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A thermal recovery and reuse system for wet desulfurization tail gas, characterized in that, It includes a cooling and condensation tower (1) and an air preheating tower (2), and the cooling and condensation tower (1) and the air preheating tower (2) are respectively provided with an air inlet and an air outlet; A condensation spraying device (4) is fixedly installed in the cooling and condensation tower (1), and a preheating spraying device (11) is fixedly installed in the air preheating tower (2); The condensation spraying device (4) includes at least one spraying layer, and each spraying layer is communicated with the air preheating tower (2) through a pipeline; The preheating spraying device (11) includes at least one spraying layer, and each spraying layer is communicated with the cooling and condensation tower (1) through a pipeline; A second air inlet (10) is provided on the side wall of the air preheating tower (2), and a second air outlet (14) is provided at the top; the preheating spraying device (11) is located between the second air inlet (10) and the second air outlet (14) in the vertical direction; The second air inlet (10) is communicated with an air inlet pipeline, and the air inlet pipeline is arranged obliquely upward; A circulating spraying device (12) is fixedly installed in the air preheating tower (2), and the circulating spraying device (12) is located above the preheating spraying device (11) in the vertical direction; A circulating pipeline (15) is provided outside the air preheating tower (2), the liquid inlet of the circulating pipeline (15) is communicated with the lower part of the air preheating tower (2), and the liquid outlet of the circulating pipeline (15) is communicated with the circulating spraying device (12).

2. The thermal recovery and reuse system for the wet desulfurization tail gas according to claim 1, characterized in that, A first air inlet (3) is provided on the side wall of the cooling and condensation tower (1), and a first air outlet (13) is provided at the top. The condensation spraying device (4) is located between the first air inlet (3) and the first air outlet (13) in the vertical direction.

3. The heat recovery and reuse system for wet desulfurization tail gas according to claim 2, wherein The position where each spraying layer of the condensation spraying device (4) is communicated with the air preheating tower (2) is located below the second air inlet (10); The position where each spraying layer of the preheating spraying device (11) is communicated with the cooling and condensation tower (1) is located below the first air inlet (3).

4. A heat recovery and reuse system for wet desulfurization tail gas according to any one of claims 1 to 3, characterized in that, An eliminator (5) is fixedly installed on the cooling and condensation tower (1), and the eliminator (5) is located above the condensation spraying device (4) in the vertical direction.

5. The thermal recovery and reuse system for the wet desulfurization tail gas according to any one of claims 1 to 3, characterized in that, Valves and discharge pumps are provided on the pipelines connected to each spraying layer, and the discharge pumps are close to the spraying layer communicated with the pipeline, and the valves are far from the spraying layer communicated with the pipeline.

6. The thermal recovery and reuse system for the wet desulfurization tail gas according to any one of claims 1 to 3, characterized in that, An external discharge pipeline (16) is also communicated with the lower part of the air preheating tower (2).

7. A method for heat recovery and reuse of wet desulfurization tail gas, characterized in that, Using the system according to any one of claims 1 to 6 for heat recovery and reuse, the heat of the wet desulfurization tail gas is transferred to the air for recovering heat through the first heat exchange process in the cooling and condensation tower (1) and the second heat exchange process in the air preheating tower (2) through circulating water.

8. The heat recovery and reuse method for wet desulfurization tail gas according to claim 7, wherein; The first heat exchange process is as follows: desulfurized tail gas is introduced into the cooling and condensation tower (1) through the air inlet on the cooling and condensation tower (1), and at the same time, the condensation spraying device (4) sprays low-temperature circulating water, so that the low-temperature circulating water exchanges heat with the desulfurized tail gas and is converted into high-temperature circulating water; The second heat exchange process is as follows: air is introduced into the air preheating tower (2) through the air inlet on the air preheating tower (2), and at the same time, the high-temperature circulating water circulates through the pipeline to the preheating spraying device (11) and is sprayed into the air preheating tower (2), so that the high-temperature circulating water exchanges heat with the air and is converted into low-temperature circulating water; After the circulating water completes one cycle through the first heat exchange process and the second heat exchange process, the next cycle is carried out.

9. The method for heat recovery and reuse of wet desulfurized tail gas according to claim 8, wherein the temperature of the low-temperature circulating water is lower than the temperature of the desulfurized tail gas introduced into the cooling and condensation tower (1); the temperature of the high-temperature circulating water is higher than the temperature of the air introduced into the air preheating tower (2).

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