Low temperature flue gas treatment system

Abstract

The present application relates to flue gas purification adsorption technical field and propose a kind of low-temperature flue gas treatment system, the low-temperature flue gas treatment system includes: boiler, heat exchanger, cooling tower, adsorption tower and regeneration tower, boiler includes tail flue, tail flue has horizontal section, bending section and vertical section in turn connected along flue gas flow direction, tail flue is equipped with located in bending section outlet and along flue gas flow direction located in outlet downstream back smoke port, heat exchanger hot side import is connected with outlet, hot side export is connected with back smoke port, cold side import is used to pass into air, cooling tower is connected with the outlet of tail flue, adsorption tower is communicated with cooling tower, regeneration tower is connected with adsorption tower.The low-temperature flue gas treatment system of the present application is set on the bending section of tail flue outlet, can avoid changing the arrangement mode of water-cooled wall of tail flue periphery, reduce construction difficulty.

Description

Technical Field

[0001] This application relates to the field of flue gas purification and adsorption technology, and in particular to a low-temperature flue gas treatment system. Background Technology

[0002] The large amount of pollutants generated by coal-fired flue gas is a significant factor harming the atmospheric environment and human health. Low-temperature flue gas treatment systems utilize the principle of low-temperature adsorption to remove pollutant components from low-temperature flue gas. The adsorption capacity of the adsorbent is also increased exponentially under low-temperature conditions. Therefore, low-temperature flue gas treatment systems have significantly improved adsorption efficiency compared to conventional flue gas adsorption systems, promoting the development of near-zero emissions for flue gas.

[0003] The low-temperature flue gas treatment system in related technologies uses heat exchange between the flue gas discharged from the boiler and the air. The heated air is then used to heat the adsorbent in the regeneration tower, thus realizing the utilization of the heat from the flue gas discharged from the boiler. However, in related technologies, the flue gas is discharged directly through openings in the tail flue of the boiler. This requires the water-cooled wall of the tail flue to be bent (i.e., a portion of the water-cooled wall in the tail flue is bent to form a certain clearance space, which facilitates the opening of the tube wall of the tail flue corresponding to the clearance space). This can easily lead to uneven distribution of the water-cooled wall and also increases the difficulty of construction. Summary of the Invention

[0004] This invention is based on the inventor's discoveries and understanding of the following facts and problems:

[0005] The inventors discovered that boiler tail flues generally have bends, and because it is difficult to tightly assemble the water-cooled wall and the tail flue at the bends, there will be a certain gap between the outer peripheral wall of the tail flue and the water-cooled wall at the bends. Therefore, by opening a hole in the gap between the outer peripheral wall of the water-cooled wall and the tail flue and installing a flue gas pipe, the flue gas at the tail of the flue can be discharged through the flue gas pipe, thereby avoiding the need for the water-cooled wall to be made of a tube, reducing the construction difficulty.

[0006] This invention aims to at least partially solve one of the technical problems in related technologies. To this end, this invention proposes a low-temperature flue gas treatment system that avoids reprocessing of water-cooled walls, reduces construction difficulty, and fully utilizes the waste heat in boiler flue gas, thereby reducing system energy consumption and production costs.

[0007] The low-temperature flue gas treatment system of the present invention includes:

[0008] A boiler, the boiler including a tail flue, the tail flue having a horizontal section, a bend section and a vertical section connected in sequence along the flue gas flow direction, the tail flue having a flue outlet located in the bend section and a flue return outlet located downstream of the flue outlet along the flue gas flow direction;

[0009] A heat exchanger having a cold-side inlet, a cold-side outlet, a hot-side outlet, and a hot-side inlet, wherein the hot-side inlet is connected to the flue gas outlet, the hot-side outlet is connected to the flue gas return outlet, and the cold-side inlet is used to introduce air so that the air exchanges heat with the flue gas introduced therein within the heat exchanger.

[0010] A cooling tower, which is connected to the outlet of the tail flue, is used to cool the flue gas introduced into it to a low temperature flue gas in the sub-zero temperature range;

[0011] An adsorption tower is connected to the cooling tower so that the low-temperature flue gas can enter the adsorption tower. The adsorption tower is provided with an adsorption layer for adsorbing and purifying the low-temperature flue gas.

[0012] A regeneration tower is connected to the adsorption tower to allow the adsorbent in the adsorption layer to circulate between the regeneration tower and the adsorption tower. The cold side outlet is connected to the adsorption tower to heat the adsorbent in the regeneration tower. The regeneration tower is used to heat and regenerate the adsorbent inside, and to cool and discharge the heated and desorbed adsorbent into the adsorption tower.

[0013] The low-temperature flue gas treatment system of this invention features a flue gas outlet at the bend in the tail flue, which avoids altering the arrangement of the water-cooled walls around the tail flue and reduces construction difficulty. Furthermore, this system can utilize waste heat from the flue gas to heat air for use as the adsorbent in the regeneration tower, thereby achieving the reuse of waste heat and avoiding the use of electric heating equipment to heat the air, thus reducing the overall system's energy consumption.

[0014] Optionally, there are multiple smoke outlets, which are arranged at intervals along the circumference of the tail flue.

[0015] The low-temperature flue gas treatment system of the present invention can open multiple flue gas outlets according to the required amount of air after heat exchange, and set multiple heat exchangers corresponding to the multiple flue gas outlets to meet different needs.

[0016] Optionally, the number of the plurality of smoke outlets is even.

[0017] In the low-temperature flue gas treatment system of the present invention, an even number of flue gas outlets are provided in the tail flue. Preferably, the multiple flue gas outlets are evenly spaced along the circumference of the tail flue, thereby ensuring that the multiple flue gas outlets can discharge flue gas evenly and ensuring that the flue gas flow in the tail flue is uniform.

[0018] Optionally, the low-temperature flue gas treatment system of the present invention further includes a low-temperature economizer and an air preheater connected in sequence by pipelines. The inlet of the low-temperature economizer is connected to the outlet of the tail flue, and the outlet of the air preheater is connected to the cooling tower, so that the flue gas generated by the boiler passes through the tail flue, the low-temperature economizer and the air preheater in sequence before entering the cooling tower.

[0019] The flue gas discharged from the tail flue of the low-temperature flue gas treatment system of the present invention can pass through a low-temperature economizer and an air preheater in sequence to achieve preliminary dust removal and waste heat reuse of the flue gas.

[0020] Optionally, the flue gas return port is located on the pipe between the tail flue and the low-temperature economizer and adjacent to the side of the low-temperature economizer, or on the pipe between the low-temperature economizer and the air preheater and adjacent to the side of the air preheater.

[0021] The low-temperature flue gas treatment system of the present invention can connect the return flue to one of the low-temperature economizer and the air preheater according to the arrangement of the air inlet of the low-temperature economizer and the air preheater, thereby avoiding the need to open holes in the tail flue again, and also ensuring that the air pollution caused by the direct discharge of flue gas after heat exchange of the heat exchanger is not caused.

[0022] Optionally, the low-temperature flue gas treatment system of the present invention further includes an isolation door disposed within the flue gas return port. The isolation door is movable between a first position and a second position. In the first position, the isolation door opens the flue gas return port to allow flue gas to flow through the flue gas return port; in the second position, the isolation door closes the flue gas return port to block the flue gas from flowing through the flue gas return port.

[0023] The low-temperature flue gas treatment system of this invention can use an isolation door to block or open the return flue gas port, ensuring that the flue gas discharged from the flue gas outlet can pass through the return flue gas port and then be introduced into the pipeline located downstream of the flue gas outlet after heat exchange, thereby ensuring smooth flow of the flue gas after heat exchange in the heat exchanger. Conversely, when the isolation door is closed, it can prevent the flow of flue gas in the heat exchanger from passing through the return flue gas port, thereby controlling the heat exchange state of the heat exchanger.

[0024] Optionally, the inner cavity of the regeneration tower includes a preheating section for preheating the adsorbent, a heating section for heating the preheated adsorbent to regenerate the adsorbent, and a cooling section for cooling the regenerated adsorbent, arranged in sequence. The heating section has a heating inlet and a heating outlet, and the heating inlet is connected to the cold side outlet so that the air after heat exchange heats the adsorbent in the heating section.

[0025] The low-temperature flue gas treatment system of the present invention opens the flue gas outlet at the bend of the tail flue and exchanges heat between the flue gas discharged from the tail flue and the air. Based on the temperature of the air after heat exchange, it can be used for the heating section of the regeneration tower. That is, the air after heat exchange is introduced into the heating section of the regeneration tower to heat the adsorbent in the heating section, so that the adsorbent is desorbed and regenerated.

[0026] Optionally, the cooling section has a cooling inlet and a cooling outlet. The cooling inlet is connected to the adsorption tower so that the flue gas purified by adsorption is introduced into the cooling section and the adsorbent in the cooling section is cooled. The cooling outlet is connected to the cold side inlet.

[0027] The low-temperature flue gas treatment system of this invention connects a cooling inlet to an adsorption tower. The cooled flue gas discharged from the adsorption tower can cool the adsorbent in the cooling section, thereby realizing the reuse of the cooling capacity of the flue gas. In addition, the flue gas after heat exchange in the cooling section is passed through a heat exchanger to exchange heat with the flue gas, and can then be passed into the heating section to heat the adsorbent in the heating section, thus realizing the reuse of the flue gas.

[0028] Optionally, the preheating section has a preheating inlet and a preheating outlet, the preheating inlet being connected to the heating outlet, so that the air in the heating section is heat-exchanged and then introduced into the preheating section to preheat the adsorbent.

[0029] The low-temperature flue gas treatment system of the present invention introduces the air after heat exchange in the heating section into the preheating section to preheat the adsorbent in the preheating section, thereby realizing the reuse of the waste heat of the air and avoiding energy waste.

[0030] Optionally, the low-temperature flue gas treatment system of the present invention further includes a mixer connected between the heating outlet and the preheating inlet. The mixer has an adjustment port for introducing a temperature regulating medium into the mixer. The temperature regulating medium is used in the mixer to mix with the air discharged from the heating section to regulate the temperature of the air.

[0031] The low-temperature flue gas adsorption and regeneration system of the present invention can use a mixer to adjust the temperature of the air introduced into the mixer so that the temperature of the mixed air in the mixer can meet the preheating requirements of the preheating section. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the low-temperature flue gas treatment system of the present invention.

[0033] Figure 2 This is a partial structural schematic diagram of the low-temperature flue gas treatment system of the present invention.

[0034] Figure 3This is a cross-sectional schematic diagram of the ventilated outer shell of the invented low-temperature flue gas treatment system.

[0035] Figure label:

[0036] Breathable outer shell 100;

[0037] Regeneration tower 1; Regeneration inlet 11; Regeneration outlet 12;

[0038] Preheating section 17; Preheating inlet 171; Preheating outlet 172;

[0039] Heating section 18; heating inlet 181; heating outlet 182;

[0040] Cooling section 19; Cooling inlet 191; Cooling outlet 192;

[0041] Boiler 2; Tail flue 21; Horizontal section 211; Bend section 212; Vertical section 213; Flue outlet 22; Return flue outlet 23;

[0042] Heat exchanger 3; hot side inlet 31; hot side outlet 32; cold side inlet 33; cold side outlet 34;

[0043] Mixer 4; Adjustment port 41;

[0044] Cooling tower 5;

[0045] Adsorption tower 6; Adsorbent inlet 61; Adsorbent outlet 62;

[0046] Low and low temperature economizer 7;

[0047] Air preheater 8. Detailed Implementation

[0048] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0049] The low-temperature flue gas treatment system of the present invention will now be described with reference to the accompanying drawings.

[0050] like Figures 1-3 As shown, the low-temperature flue gas treatment system of the present invention includes: a boiler 2, a heat exchanger 3, a cooling tower 5, an adsorption tower 6, and a regeneration tower 1.

[0051] The boiler 2 includes a tail flue 21, which has a horizontal section 211, a bend section 212, and a vertical section 213 connected sequentially along the flue gas flow direction. The tail flue 21 is provided with a flue gas outlet 22 located at the bend section 212 and a flue gas return outlet 23 located downstream of the flue gas outlet 22 along the flue gas flow direction. The heat exchanger 3 has a cold-side inlet 33, a cold-side outlet 34, a hot-side outlet 32, and a hot-side inlet 31. The hot-side inlet 31 is connected to the flue gas outlet 22, and the hot-side outlet 32 ​​is connected to the flue gas return outlet 23. The cold-side inlet 33 is used to introduce air so that the air exchanges heat with the flue gas introduced into it within the heat exchanger 3.

[0052] Specifically, such as Figure 1 and Figure 2 As shown, the flue gas in boiler 2 flows in the direction indicated by the arrow, that is, the flue gas flows through the horizontal section 211, the bend section 212 and the vertical section 213 in sequence. The flue gas outlet 22 is opened on the side wall of the bend section 212. The flue gas outlet 22 is connected to the hot side inlet 31 through a pipe so that the flue gas in boiler 2 can enter the heat exchanger 3 through the flue gas outlet 22 and the hot side inlet 31.

[0053] It should be noted that the outer peripheral wall of the tail flue 21 is also provided with a water-cooled wall (not shown in the figure). The inner peripheral wall of the water-cooled wall is adapted to the outer peripheral wall of the tail flue 21. During the installation of the water-cooled wall, due to factors such as errors and construction process, a certain gap may occur between the outer peripheral wall of the bend section 212 of the tail flue 21 and the inner peripheral wall of the corresponding water-cooled wall. Therefore, a flue outlet 22 is opened in the bend section 212 and a flue pipe is connected to it so that the flue gas in the tail flue 21 can be discharged along the flue pipe. This avoids the need for bending the water-cooled wall and reduces the construction difficulty.

[0054] It is understandable that the water-cooled wall is composed of multiple water-cooled tubes arranged sequentially along the length direction orthogonal to the water-cooled tubes. The water-cooled wall is installed on the outer peripheral wall of the tail flue 21, and the side of the water-cooled wall adjacent to the tail flue 21 is the inner peripheral wall of the water-cooled wall.

[0055] Cooling tower 5 is connected to the outlet of tail flue 21. Cooling tower 5 is used to cool the flue gas entering it to a low temperature of sub-zero. Adsorption tower 6 is connected to cooling tower 5 so that the low temperature flue gas can enter adsorption tower 6. Adsorption tower 6 is equipped with an adsorption layer, which is used to adsorb and purify the low temperature flue gas. Regeneration tower 1 is connected to adsorption tower 6 so that the adsorbent in the adsorption layer can circulate between regeneration tower 1 and adsorption tower 6. Cold side outlet 34 is connected to adsorption tower 6 to heat the adsorbent in regeneration tower 1. Regeneration tower 1 is used to heat and regenerate the adsorbent inside it, and then cools the heated and desorbed adsorbent before discharging it into adsorption tower 6.

[0056] Specifically, such as Figure 1 and Figure 2As shown, the cooling tower 5 is connected to the outlet of the tail flue 21 via a pipe, allowing the flue gas discharged from the tail flue 21 to enter the cooling tower 5 for cooling. The cooling tower 5 is connected to the adsorption tower 6, so that the cooled flue gas can enter the adsorption tower 6 and be purified by the adsorbent in the adsorption tower 6. Specifically, the cooling tower 5 can cool the flue gas to a low-temperature clean flue gas (below 0℃). After the low-temperature clean flue gas enters the adsorption tower 6, the adsorption effect of the adsorbent is greatly improved in the low-temperature environment, further enhancing the purification effect of the flue gas.

[0057] It is understood that the adsorption tower 6 includes an adsorbent inlet 61 and an adsorbent outlet 62, and the regeneration tower 1 includes a regeneration inlet 11 and a regeneration outlet 12. The adsorbent inlet 61 is connected to the regeneration outlet 12, and the adsorbent outlet 62 is connected to the regeneration inlet 11, so that the adsorbent circulates between the adsorption tower 6 and the regeneration tower 1.

[0058] Preferably, the cooling tower 5 is capable of cooling the flue gas to -20°C to -15°C.

[0059] It should be noted that, as Figure 3 As shown, the adsorbent can be filled inside the permeable shell 100 for adsorption. The adsorbent can be granular or powdered, or it can be an adsorbent body made of powder or granular adsorbent, such as a spherical or cylindrical body formed by binding powder or granular adsorbent with a binder. Of course, a protective shell can be further formed on the outside of the adsorbent body, such as a permeable membrane covering the outside of the adsorbent body, to improve the strength of the adsorbent body. The permeable shell has vents, through which flue gas can enter the permeable shell. The flue gas can pass through the gaps between adjacent adsorbents and / or the pores of the adsorbent itself, thereby reducing direct collisions, friction and wear between adsorbents, and dust generation. The permeable shell can be in the shape of a sphere, cylinder, or other rotating body, wherein the diameter of the permeable shell 100 is 10mm-100mm, and the diameter of the adsorbent is 1mm-10mm.

[0060] The low-temperature flue gas treatment system of the present invention has a flue gas outlet 22 opened on the bend section 212 of the tail flue 21, which can avoid changing the arrangement of the water-cooled walls around the tail flue 21 and reduce the construction difficulty. In addition, the low-temperature flue gas treatment system of the present invention can also use the waste heat of flue gas to heat the air for use in the adsorbent of the regeneration tower 1, thereby realizing the reuse of waste heat of flue gas, avoiding the use of electric heating equipment to heat the air, and reducing the power consumption of the overall system.

[0061] Preferably, there are multiple flue gas outlets 22, which are arranged at intervals along the circumference of the tail flue 21. That is, the low-temperature flue gas treatment system of the present invention can open multiple flue gas outlets 22 according to the required amount of air after heat exchange, and set multiple heat exchangers 3 corresponding to the multiple flue gas outlets 22 to meet different needs.

[0062] Optionally, the number of multiple smoke outlets 22 is even. It is understood that the low-temperature flue gas treatment system of the present invention has an even number of smoke outlets 22 in the tail flue 21. Preferably, the multiple smoke outlets 22 are evenly spaced along the circumference of the tail flue 21, thereby ensuring that the multiple smoke outlets 22 can discharge flue gas evenly and ensuring that the flue gas flow in the tail flue 21 is uniform.

[0063] Optionally, the low-temperature flue gas treatment system of the present invention further includes a low-temperature economizer 7 and an air preheater 8 connected in sequence by pipes. The inlet of the low-temperature economizer 7 is connected to the outlet of the tail flue 21, and the outlet of the air preheater 8 is connected to the cooling tower 5, so that the flue gas generated by the boiler 2 passes through the tail flue 21, the low-temperature economizer 7 and the air preheater 8 in sequence before entering the cooling tower 5.

[0064] Specifically, such as Figure 1 and Figure 2 As shown, the exhaust port of the tail flue 21, the low-temperature economizer 7, and the air preheater 8 are connected in sequence by pipes so that the flue gas discharged from the tail flue 21 can pass through the low-temperature economizer 7 and the air preheater 8 in sequence to achieve preliminary dust removal and waste heat reuse of the flue gas.

[0065] Optionally, the flue gas return port 23 is located on the pipe between the tail flue 21 and the low-temperature economizer 7 and adjacent to the side of the low-temperature economizer 7, or on the pipe between the low-temperature economizer 7 and the air preheater 8 and adjacent to the side of the air preheater 8.

[0066] Specifically, such as Figure 1 and Figure 2 As shown, the flue gas return port 23 is located on the pipe between the tail flue 21 and the low-temperature economizer 7 and is adjacent to the side of the low-temperature economizer 7, so that the flue gas after heat exchange in the heat exchanger 3 can first pass through the low-temperature economizer 7 for preliminary dust removal, so as to avoid the particulate matter carried in the flue gas from clogging the pipe.

[0067] In other words, the low-temperature flue gas treatment system of the present invention can connect the return flue gas port 23 to one of the low-temperature economizer 7 and the air preheater 8 according to the arrangement of the air inlet of the low-temperature economizer 7 and the air preheater 8, thereby avoiding the need to open holes in the tail flue 21 again, and also ensuring that the air pollution caused by the direct discharge of the flue gas after heat exchange by the heat exchanger 3 is not caused.

[0068] Optionally, the low-temperature flue gas treatment system of the present invention further includes an isolation door (not shown in the figure), which is disposed in the flue gas return port 23. The isolation door is movable between a first position and a second position. In the first position, the isolation door opens the flue gas return port 23 to allow flue gas to flow through the flue gas return port 23; in the second position, the isolation door closes the flue gas return port 23 to block the flue gas from flowing through the flue gas return port 23.

[0069] It is understandable that, such as Figure 2 As shown, in the first position, the isolation door is open, and the flue gas return port 23 connects the heat exchanger 3 and the low-temperature economizer 7, allowing the flue gas after heat exchange in the heat exchanger 3 to enter the low-temperature economizer 7 through the flue gas return port 23. In the second position, the isolation door is closed, preventing the flue gas in the heat exchanger 3 from passing through the flue gas return port 23.

[0070] In other words, the low-temperature flue gas treatment system of the present invention can use the isolation door to block or open the return flue port 23, ensuring that the flue gas discharged from the outlet 22 can pass through the return flue port 23 and then be introduced into the pipeline located downstream of the outlet 22 after heat exchange, so as to ensure the smooth flow of flue gas after heat exchange in the heat exchanger 3. Conversely, when the isolation door is closed, it can prevent the flow of flue gas in the heat exchanger 3 through the return flue port 23, so as to control the heat exchange state of the heat exchanger 3.

[0071] Optionally, the inner cavity of the regeneration tower 1 includes a preheating section 17 for preheating the adsorbent, a heating section 18 for heating the preheated adsorbent to regenerate the adsorbent, and a cooling section 19 for cooling the regenerated adsorbent, arranged in sequence. The heating section 18 has a heating inlet 181 and a heating outlet 182. The heating inlet 181 is connected to the cold side outlet 34 so that the heat-exchanged air heats the adsorbent in the heating section 18.

[0072] Specifically, such as Figure 1 and Figure 2 As shown, the heating inlet 181 is located below the heating outlet 182. The air introduced into the heat exchanger 3 through the heating inlet 181 exchanges heat with the flue gas discharged from the tail flue 21, so that the temperature of the clean air is heated to 300℃-450℃. This ensures that the air entering the heating section 18 through the heating inlet 181 can heat the adsorbent in the heating section 18, thereby causing the adsorbent in the heating section 18 to be desorbed by heat.

[0073] The low-temperature flue gas treatment system of the present invention has the flue gas outlet 22 located at the bend section 212 of the tail flue 21, and the flue gas discharged from the tail flue 21 exchanges heat with the air. According to the temperature of the air after heat exchange, it can be used for the heating section 18 of the regeneration tower 1. That is, the air after heat exchange is introduced into the heating section 18 of the regeneration tower 1 to heat the adsorbent in the heating section 18, so that the adsorbent is desorbed and regenerated.

[0074] Optionally, the cooling section 19 has a cooling inlet 191 and a cooling outlet 192. The cooling inlet 191 is connected to the adsorption tower 6 so that the flue gas after adsorption and purification can be passed into the cooling section 19 and the adsorbent in the cooling section 19 can be cooled. The cooling outlet 192 is connected to the cold side inlet 33.

[0075] It is understandable that the cooling inlet 191 is connected to the adsorption tower 6 through a pipeline. The low-temperature clean flue gas discharged from the adsorption tower 6 can enter the cooling section 19 through the cooling inlet 191 to cool the adsorbent in the cooling section 19. The low-temperature clean flue gas after heat exchange in the cooling section 19 enters the heat exchanger 3 through the cooling outlet 192 to exchange heat with the flue gas and form high-temperature clean flue gas (its temperature is 300℃-450℃), which is then passed into the heating section 18 to heat the adsorbent in the heating section 18.

[0076] In other words, in the regeneration tower 1, the adsorbent flows from the heating section 18 to the cooling section 19, and the temperature of the adsorbent discharged from the heating section 18 is relatively high, so it cannot be directly discharged from the regeneration tower 1. Therefore, it needs to be cooled first by passing it into the cooling section 19. The low-temperature flue gas treatment system of the present invention uses the low-temperature clean flue gas discharged from the cooling tower 5 to the cooling section 19 of the regeneration tower 1, which can avoid the need to use refrigeration equipment (such as a refrigerator) to first provide cooling capacity to generate air with cooling capacity, and then use the air to cool the cooling section 19. This further reduces the overall energy consumption of the system, reduces production costs, and also has the advantage of good cooling effect.

[0077] Furthermore, in the cooling section 19, the low-temperature clean flue gas is heated after exchanging heat with the adsorbent. Therefore, when the heated clean flue gas is introduced into the heat exchanger 3, the clean flue gas already has a certain temperature, resulting in higher heat exchange efficiency in the heat exchanger 3.

[0078] Therefore, the low-temperature flue gas treatment system of the present invention connects the cooling inlet 191 to the adsorption tower 6. The cooled clean flue gas discharged from the adsorption tower 6 can cool the adsorbent in the cooling section 19, thereby realizing the reuse of the cooling capacity of the clean flue gas. In addition, after heat exchange in the cooling section 19, the clean flue gas is passed into the heat exchanger 3 for heat exchange with the flue gas, and then passed into the heating section 18 to heat the adsorbent in the heating section 18, thus realizing the reuse of the clean flue gas.

[0079] Optionally, the preheating section 17 has a preheating inlet 171 and a preheating outlet 172. The preheating inlet 171 is connected to the heating outlet 182 so that the air in the heating section 18 is heat-exchanged and then introduced into the preheating section 17 to preheat the adsorbent.

[0080] In other words, the low-temperature flue gas treatment system of the present invention introduces the air after heat exchange in the heating section 18 into the preheating section 17 to preheat the adsorbent in the preheating section 17, thereby realizing the reuse of waste heat of the air and avoiding energy waste.

[0081] Optionally, the low-temperature flue gas treatment system of the present invention further includes a mixer 4, which is connected between the heating outlet 182 and the preheating inlet 171. The mixer 4 has an adjustment port 41 for introducing a temperature regulating medium into the mixer 4. The temperature regulating medium is used in the mixer 4 to mix with the air discharged from the heating section 18 to regulate the temperature of the air.

[0082] It is understandable that the preheating temperature required for the preheating section 17 of the regeneration tower 1 is generally 80℃-100℃. The temperature of the clean flue gas after heat exchange in the heating section 18 may be slightly higher than the preheating temperature required for the preheating section 17. Therefore, preferably, the clean flue gas after heat exchange in the heat exchanger 3 can be first introduced into the mixer 4, and then temperature-controlled air (i.e., ambient temperature air) or low-temperature clean flue gas can be introduced into the mixer 4 to reduce the temperature of the clean flue gas after heat exchange to the preheating temperature required for the preheating section 17.

[0083] The low-temperature flue gas adsorption and regeneration system of the present invention can use the mixer 4 to adjust the temperature of the air introduced into the mixer 4 so that the temperature of the mixed air in the mixer 4 can meet the preheating requirements of the preheating section 17.

[0084] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to 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 invention.

[0085] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0086] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0087] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0088] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0089] Although the above embodiments have been shown and described, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Any changes, modifications, substitutions and variations made to the above embodiments by those skilled in the art are within the protection scope of the present invention.

Claims

1. A low-temperature flue gas treatment system, characterized in that, include: A boiler, the boiler including a tail flue, the tail flue having a horizontal section, a bend section and a vertical section connected in sequence along the flue gas flow direction, the tail flue having a flue outlet located in the bend section and a flue return outlet located downstream of the flue outlet along the flue gas flow direction; A heat exchanger having a cold-side inlet, a cold-side outlet, a hot-side outlet, and a hot-side inlet, wherein the hot-side inlet is connected to the flue gas outlet, the hot-side outlet is connected to the flue gas return outlet, and the cold-side inlet is used to introduce air so that the air exchanges heat with the flue gas introduced therein within the heat exchanger. A cooling tower, which is connected to the outlet of the tail flue, is used to cool the flue gas introduced into it to a low temperature flue gas in the sub-zero temperature range; An adsorption tower is connected to the cooling tower so that the low-temperature flue gas can enter the adsorption tower. The adsorption tower is provided with an adsorption layer for adsorbing and purifying the low-temperature flue gas. A regeneration tower is connected to the adsorption tower to allow the adsorbent in the adsorption layer to circulate between the regeneration tower and the adsorption tower. The cold side outlet is connected to the adsorption tower to heat the adsorbent in the regeneration tower. The regeneration tower is used to heat and regenerate the adsorbent inside, and to cool and discharge the heated and desorbed adsorbent into the adsorption tower. The inner cavity of the regeneration tower includes a preheating section for preheating the adsorbent, a heating section for heating the preheated adsorbent to regenerate the adsorbent, and a cooling section for cooling the regenerated adsorbent, arranged sequentially. The heating section has a heating inlet and a heating outlet, and the heating inlet is connected to the cold side outlet so that the air after heat exchange heats the adsorbent in the heating section. The cooling section has a cooling inlet and a cooling outlet. The cooling inlet is connected to the cooling section so that the purified flue gas can be introduced into the cooling section and the adsorbent in the cooling section can be cooled. The cooling outlet is connected to the cold side inlet. The preheating section has a preheating inlet and a preheating outlet. The preheating inlet is connected to the heating outlet so that the air in the heating section is heat-exchanged and then introduced into the preheating section to preheat the adsorbent.

2. The low-temperature flue gas treatment system according to claim 1, characterized in that, There are multiple smoke outlets, which are arranged at intervals along the circumference of the tail flue.

3. The low-temperature flue gas treatment system according to claim 2, characterized in that, The number of the multiple smoke outlets is even.

4. The low-temperature flue gas treatment system according to claim 1, characterized in that, It also includes a low-temperature economizer and an air preheater connected in sequence by pipes. The inlet of the low-temperature economizer is connected to the outlet of the tail flue, and the outlet of the air preheater is connected to the cooling tower, so that the flue gas generated by the boiler passes through the tail flue, the low-temperature economizer and the air preheater in sequence before entering the cooling tower.

5. The low-temperature flue gas treatment system according to claim 4, characterized in that, The flue gas return port is located on the pipe between the tail flue and the low-temperature economizer and adjacent to the side of the low-temperature economizer, or on the pipe between the low-temperature economizer and the air preheater and adjacent to the side of the air preheater.

6. The low-temperature flue gas treatment system according to claim 5, characterized in that, It also includes an isolation door, which is located inside the smoke return vent and is movable between a first position and a second position. In the first position, the isolation door opens the smoke return port to allow smoke to flow through the smoke return port; In the second position, the isolation door closes the smoke return port to block the flow of flue gas through the smoke return port.

7. The low-temperature flue gas treatment system according to claim 1, characterized in that, It also includes a mixer connected between the heating outlet and the preheating inlet, the mixer having an adjustment port for introducing a temperature regulating medium into the mixer, the temperature regulating medium being used in the mixer to mix with the air discharged from the heating section to regulate the temperature of the air.

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