Flue gas low-temperature purification system

Abstract

A flue gas low-temperature purification system. The flue gas low-temperature purification system comprises: a spray column (1), an adsorption column (2), a regeneration column (3), a heat exchanger (4) and an absorption refrigerator (5), wherein the spray column (1) is used for cooling flue gas to low-temperature flue gas at subzero temperature; the adsorption column (2) is used for adsorbing the low-temperature flue gas and purifying same into clean flue gas; the regeneration column (3) is used for heating an adsorbent in the regeneration column (3) for regeneration; the regeneration column (3) is connected to the adsorption column (2), so that the adsorbent circulates between the adsorption column (2) and the regeneration column (3); a heat exchange medium introduced from a cold side inlet (43) in the heat exchanger (4) exchanges heat with the flue gas discharged from a boiler flue and then is supplied into the regeneration column (3); a generator inlet (51) of the absorption refrigerator (5) is connected to a hot side outlet (42); an evaporator inlet (53) of the absorption refrigerator (5) is connected to a spray liquid outlet of the spray column (1); and an evaporator outlet (54) of the absorption refrigerator (5) is connected to a spray liquid inlet of the spray column (1) for cooling spray liquid.

Description

Flue gas low temperature purification system

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This disclosure is based on and claims the priority of Chinese patent application with application number 202410281169.2 and application date March 12, 2024. The entire content of the Chinese patent application is hereby incorporated into this disclosure by reference. Technical Field

[0003] The present disclosure relates to the technical field of flue gas purification, and in particular to a low-temperature flue gas purification system. Background Art

[0004] Low-temperature integrated pollutant removal technology is a comprehensive flue gas pollutant treatment technology based on the principle of low-temperature adsorption denitrification of flue gas. It first removes SO2 and residual moisture through a desulfurization adsorption tower, while also adsorbing SO3, Hg, HCl, HF, VOCs, and a small amount of NOx. After desulfurization and dehumidification, the flue gas is cooled to a sub-zero temperature range before entering a low-temperature denitrification adsorption tower. NOx is deeply adsorbed and removed at low temperatures, achieving the dual goals of 'integrated removal' and 'near-zero emissions' of pollutants.

[0005] In related technologies, deep cooling flue gas to below room temperature requires conventional electric chillers, which consume significant amounts of electricity. This is particularly true as the flue gas temperature decreases, reducing the chiller's cooling coefficient and increasing power consumption. Similarly, the adsorbent in the regeneration tower must be heated to temperatures exceeding 300°C to meet regeneration temperature requirements. Therefore, high-quality steam or other media are required to heat the adsorbent, consuming significant energy and requiring heaters to heat the regeneration tower's adsorbent. Both methods consume significant energy and are uneconomical. Summary of the Invention

[0006] The present disclosure is based on the inventors' findings and understanding of the following facts and problems:

[0007] As flue gas is discharged, its temperature gradually decreases. If not utilized, this would result in a significant amount of waste heat in the flue gas. In related technologies, the heating section of the regeneration tower requires a large amount of high-temperature heat medium (such as clean air at approximately 400°C) to be passed through the heating section to heat the adsorbent. Therefore, the inventors utilize the waste heat from the flue gas to heat the clean air, passing the heat-exchanged clean air through the heating section to utilize the waste heat from the flue gas and avoid energy waste.

[0008] The present disclosure aims to solve at least one of the technical problems in the related art to a certain extent. To this end, the present disclosure proposes a low-temperature flue gas purification system that can realize multiple utilization of flue gas waste heat and has the advantage of low energy consumption.

[0009] The flue gas low-temperature purification system disclosed herein comprises:

[0010] A spray tower, the spray tower having a smoke inlet and a smoke exhaust port, the spray tower being used to cool the smoke introduced from the smoke inlet into low-temperature smoke at a sub-zero temperature;

[0011] an adsorption tower having an adsorbent inlet, an adsorbent outlet, and a flue gas inlet connected to the flue gas outlet, and configured to adsorb and purify the low-temperature flue gas introduced through the flue gas inlet into clean flue gas;

[0012] a regeneration tower, the regeneration tower comprising a heating section for heating and regenerating an adsorbent therein, the regeneration tower having a regeneration inlet and a regeneration outlet, the regeneration inlet being connected to the adsorbent outlet, and the regeneration outlet being connected to the adsorbent inlet, so that the adsorbent circulates between the adsorption tower and the regeneration tower;

[0013] a heat exchanger having a hot side inlet and a hot side outlet connected to the boiler flue, a cold side inlet for introducing a heat exchange medium, and a cold side outlet connected to the heating section, wherein the heat exchange medium introduced into the cold side inlet exchanges heat with the flue gas discharged from the boiler flue in the heat exchanger and is then supplied to the heating section;

[0014] An absorption refrigerator, wherein the generator inlet of the absorption refrigerator is connected to the hot side outlet, the evaporator inlet of the absorption refrigerator is connected to the spray liquid outlet of the spray tower, and the evaporator outlet of the absorption refrigerator is connected to the spray liquid inlet of the spray tower, so as to cool the spray liquid in the evaporator of the absorption refrigerator.

[0015] The disclosed low-temperature flue gas purification system first utilizes flue gas discharged from the boiler flue to exchange heat with clean air. The clean air after heat exchange heats the adsorbent in the heating section, achieving a primary utilization of the flue gas's waste heat. The heat exchanged flue gas then serves as a power source to drive an absorption chiller to generate cooling capacity, thereby achieving a secondary utilization of the flue gas's waste heat. Furthermore, the cooling capacity generated by the absorption chiller can be used to cool the spray liquid in the spray tower, replacing the spray tower's existing refrigeration equipment (such as a chiller), thereby reducing electricity consumption.

[0016] In addition, the flue gas after heat exchange still has a certain amount of heat. The inventor uses the flue gas after heat exchange as a driving energy to drive the absorption refrigerator. The cold energy generated by the absorption refrigerator can also be used to cool the spray liquid of the spray tower, further utilizing the heat of the flue gas and avoiding excessive consumption of electricity by the purification system.

[0017] Optionally, the generator outlet of the absorption refrigeration machine is connected to the smoke inlet of the spray tower.

[0018] The flue gas used as the driving source in the low-temperature flue gas purification system disclosed herein is then passed through a spray tower for spray treatment after use, preventing the flue gas from being discharged into the atmosphere and polluting the environment. The flue gas temperature is much lower than that of flue gas directly discharged from the boiler, thus facilitating the spray tower's cooling process.

[0019] Optionally, the regeneration tower also includes a preheating section located above the heating section, the preheating section having a first downpipe and a first medium flow channel, the heating section having a second downpipe and a second medium flow channel, the first downpipe being used to guide the adsorbent to fall in the preheating section, the second downpipe being used to guide the adsorbent to fall in the heating section, the first medium flow channel being used to introduce a first heat exchange medium for preheating the adsorbent in the first downpipe, and the second medium flow channel being used to introduce a second heat exchange medium for heating the adsorbent in the second downpipe.

[0020] The preheating section and heating section of the flue gas low-temperature purification system disclosed herein both adopt an indirect heat exchange method, which can not only avoid the mutual interference of high-temperature air or water vapor generated by the adsorbent during the cooling process, but also prevent impurities in the air from mixing into the adsorbent and affecting the adsorption effect of the adsorbent.

[0021] Optionally, the regeneration tower also includes a cooling section located below the heating section, and the cooling section has a third discharge pipe and a third medium flow channel. The third discharge pipe is used to guide the adsorbent to fall in the cooling section, and the flue gas outlet of the adsorption tower is connected to the third medium flow channel so that the flue gas discharged from the flue gas outlet of the adsorption tower enters the third medium flow channel to cool the adsorbent in the third discharge pipe.

[0022] The adsorbent in the heating section of the low-temperature flue gas purification system disclosed herein can flow to the third discharge pipe after heat exchange and analysis with high-temperature air. At this time, the adsorbent has a certain temperature. Research has found that if the adsorbent at this temperature flows directly to the adsorption tower, the adsorption and purification effect on the flue gas is relatively weak. Therefore, by introducing low-temperature clean flue gas into the cooling section to cool the adsorbent in the third discharge pipe, the adsorption effect of the adsorbent in the adsorption tower can be improved.

[0023] Optionally, the heat exchanger includes a shell and a heat exchange tube arranged in the shell, the inner cavity of the shell constitutes a hot side space connected to the hot side inlet and the hot side outlet, and the inner cavity of the heat exchange tube constitutes a cold side space connected to the cold side inlet and the cold side outlet.

[0024] In the flue gas low-temperature purification system disclosed herein, the flue gas discharged from the boiler flue and the clean air are exchanged in an indirect manner in the heat exchanger to avoid air pollution.

[0025] Optionally, the flue gas low-temperature purification system disclosed herein further includes a cold recovery component, and at least one of the smoke exhaust port, the smoke outlet, and the smoke outlet of the cooling section is connected to the cold recovery component.

[0026] In the flue gas low-temperature purification system disclosed herein, a cold energy recovery component can be used to recover cold energy from the flue gas discharged from the smoke exhaust port, the smoke gas discharged from the smoke outlet, and the smoke gas discharged from the cooling section, thereby avoiding waste of flue gas cold energy.

[0027] Optionally, the spray cooling tower includes multiple spray components, and the spray tower has multiple spray areas. The multiple spray areas are arranged in sequence along the flue gas flow direction in the spray tower. The multiple spray components correspond one-to-one to the multiple spray areas, and are used to spray and cool the flue gas flowing through the multiple spray areas in sequence to low-temperature flue gas at sub-zero temperature.

[0028] The flue gas low-temperature purification system disclosed herein can utilize multiple spray assemblies to spray and cool different spray areas in the spray tower, so that the flue gas in the spray tower is cooled step by step along its flow direction until the flue gas temperature drops below 0°C.

[0029] Optionally, the cold recovery component includes a cold recovery tower and a cold exchanger, the cold recovery tower is connected to the smoke exhaust port of the adsorption tower and the cold exchanger, the circulating liquid in the cold exchanger exchanges cold with the clean flue gas in the cooling recovery tower to recover the cold in the clean flue gas, and the cold exchanger is connected to at least one of the multiple spray areas to indirectly cool the spray liquid discharged from the at least one spray area and supply the cooled spray liquid to the spray component corresponding to the at least one spray area.

[0030] The flue gas low-temperature purification system disclosed in the present invention can utilize a cold recovery component to recover cold in the flue gas, and can reuse it to cool the spray liquid discharged from the spray area, and then pass the cooled spray liquid into its corresponding spray area, thereby realizing the recovery and reuse of cold.

[0031] Optionally, the multiple spray areas include a primary spray area, a secondary spray area, a tertiary spray area and a quaternary spray area arranged in sequence along the flue gas flow direction; the multiple spray assemblies include a primary spray assembly, a secondary spray assembly, a tertiary spray assembly and a quaternary spray assembly; the cold exchanger is connected to the spray liquid outlet of the secondary spray area and the spray liquid inlet of the secondary spray assembly.

[0032] The flue gas low-temperature purification system disclosed in the present invention divides the spray tower into four spray zones, further optimizing the step-by-step cooling effect of the spray tower and avoiding excessive temperature differences between two adjacent spray zones, which would result in excessive cooling capacity being consumed to cool the spray liquid.

[0033] Optionally, the evaporator inlet of the absorption refrigeration machine is connected to the spray liquid outlet of the four-stage spray zone, and the evaporator outlet of the absorption refrigeration machine is connected to the spray liquid inlet of the four-stage spray assembly.

[0034] The cooling capacity generated by the absorption refrigerator of the flue gas low-temperature purification system disclosed herein can be used to cool the spray liquid of the four-stage spray assembly, thereby avoiding the use of a low-temperature refrigerator and correspondingly reducing the power consumption of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] FIG1 is a schematic structural diagram of a low-temperature flue gas purification system disclosed herein.

[0036] FIG2 is a schematic structural diagram of the flue gas low-temperature purification system disclosed in the present invention.

[0037] FIG3 is a schematic structural diagram of a regeneration tower of the flue gas low-temperature purification system disclosed herein.

[0038] FIG4 is a schematic cross-sectional view of the air-permeable housing of the low-temperature flue gas purification system of the present disclosure.

[0039] Reference numerals:

[0040] Breathable outer shell 100;

[0041] Spray tower 1; smoke inlet 11; smoke exhaust outlet 12; primary spray area 131; secondary spray area 132; tertiary spray area 133; quaternary spray area 134; primary spray assembly 141; secondary spray assembly 142; tertiary spray assembly 143; quaternary spray assembly 144;

[0042] Adsorption tower 2; flue gas inlet 21; flue gas outlet 22; adsorbent inlet 23; adsorbent outlet 24;

[0043] Regeneration tower 3; preheating section 31; first feed pipe 311; first medium flow channel 312; heating section 32; second feed pipe 321; second medium flow channel 322; cooling section 33; third feed pipe 331; third medium flow channel 332; regeneration inlet 34; regeneration outlet 35;

[0044] Heat exchanger 4; hot side inlet 41; hot side outlet 42; cold side inlet 43; cold side outlet 44;

[0045] Absorption refrigerator 5; generator inlet 51; generator outlet 52; evaporator inlet 53; evaporator outlet 54;

[0046] Cold recovery component 6; cold recovery tower 61; cold exchanger 62;

[0047] Medium temperature refrigerator 7. DETAILED DESCRIPTION

[0048] The embodiments of the present disclosure are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present disclosure, but should not be understood as limiting the present disclosure.

[0049] As shown in FIG1 to FIG4 , the flue gas low-temperature purification system disclosed herein includes: a spray tower 1 , an adsorption tower 2 , a regeneration tower 3 , a heat exchanger 4 and an absorption refrigerator 5 .

[0050] The spray tower 1 has a smoke inlet 11 and a smoke exhaust port 12. The spray tower 1 is used to cool the flue gas introduced from the smoke inlet 11 to a low-temperature flue gas having a sub-zero temperature. The adsorption tower 2 has an adsorbent inlet 23, an adsorbent outlet 24, and a flue gas inlet 21 connected to the smoke exhaust port 12. The adsorption tower 2 is used to adsorb and purify the low-temperature flue gas introduced through the flue gas inlet 21 into clean flue gas. The regeneration tower 3 includes a heating section 32 for heating and regenerating the adsorbent therein. The regeneration tower 3 has a regeneration inlet 34 and a regeneration outlet 35. The regeneration inlet 34 is connected to the adsorbent outlet 24, and the regeneration outlet 35 is connected to the adsorbent inlet 23, so that the adsorbent circulates between the adsorption tower 2 and the regeneration tower 3.

[0051] It is understandable that the smoke inlet 11 of the spray tower 1 is connected to the boiler flue, so that the smoke discharged from the boiler flue can pass into the spray tower 1, and the spray tower 1 is used to spray and cool the smoke.

[0052] Optionally, the temperature of the low-temperature flue gas is -20°C to -15°C.

[0053] Heat exchanger 4 has a hot side inlet 41 connected to the boiler flue, a hot side outlet 42, a cold side inlet 43 for introducing a heat exchange medium, and a cold side outlet 44 connected to heating section 32. Within heat exchanger 4, the heat exchange medium introduced through cold side inlet 43 exchanges heat with flue gas discharged from the boiler flue before being supplied to heating section 32. Generator inlet 51 of absorption chiller 5 is connected to hot side outlet 42, while evaporator inlet 53 of absorption chiller 5 is connected to the spray liquid outlet of spray tower 1. Evaporator outlet 54 of absorption chiller 5 is connected to the spray liquid inlet of spray tower 1, thereby cooling the spray liquid within the evaporator of absorption chiller 5.

[0054] It is understood that a portion of the flue gas discharged from the boiler flue is passed into the spray tower 1, and a portion is passed into the heat exchanger 4 through the hot side inlet 41 to exchange heat with the heat exchange medium in the heat exchanger 4. In the heat exchanger 4, the flue gas after heat exchange is passed into the generator inlet 51 of the absorption chiller 5 through the hot side outlet 42. In other words, the flue gas after heat exchange is used as a power source to drive the absorption chiller 5. The absorption chiller 5 can generate cooling energy, thereby realizing multiple utilization of the flue gas waste heat.

[0055] When the absorption refrigerator is in use (taking the lithium bromide absorption refrigerator as an example), the lithium bromide solution in the absorber is extracted into the generator by a solution pump, and the lithium bromide solution in the generator is heated by a high-temperature heat source (high-temperature flue gas, etc.) to evaporate the lithium bromide solution to form lithium bromide gas, which is then passed into the condenser. The lithium bromide gas is condensed and liquefied in the condenser and then reduced in pressure by a throttle before being passed into the evaporator. The lithium bromide solution is evaporated in the evaporator and can absorb heat from the surrounding environment, thereby cooling the spray liquid passed into the evaporator.

[0056] It should be noted that the heat exchange medium can be air, high-temperature resistant oil, molten salt, etc., among which the air can be purified air. The heat exchange medium in the subsequent description of this disclosure is explained using purified air as an example, hereinafter referred to as "clean air".

[0057] Thus, the low-temperature flue gas purification system disclosed herein can first utilize the flue gas discharged from the boiler flue to exchange heat with clean air, and then use the clean air after heat exchange to heat the adsorbent in the heating section 32, thereby realizing the first utilization of the flue gas waste heat. The flue gas after heat exchange is then used as a power source to drive the absorption chiller 5 to generate cold energy, thereby realizing the second utilization of the flue gas waste heat. In addition, the cold energy generated by the absorption chiller 5 can be used to cool the spray liquid of the spray tower 1, replacing the original refrigeration equipment (such as a refrigerator, etc.) of the spray tower 1, thereby reducing energy consumption.

[0058] Optionally, the generator outlet 52 of the absorption chiller 5 is connected to the smoke inlet 11 of the spray tower 1. In other words, the flue gas used as the driving source in the low-temperature flue gas purification system of the present disclosure is passed into the spray tower 1 for spray treatment after use, preventing the flue gas from being discharged into the atmosphere and polluting the environment. The flue gas temperature is much lower than that of the flue gas directly discharged from the boiler, thus facilitating the spray cooling treatment of the spray tower 1.

[0059] Optionally, the regeneration tower 3 also includes a preheating section 31 located above the heating section 32, the preheating section 31 having a first downpipe 311 and a first medium flow channel 312, and the heating section 32 having a second downpipe 321 and a second medium flow channel 322. The first downpipe 311 is used to guide the adsorbent to fall in the preheating section 31, the second downpipe 321 is used to guide the adsorbent to fall in the heating section 32, the first medium flow channel 312 is used to introduce a first heat exchange medium for preheating the adsorbent in the first downpipe, and the second medium flow channel 322 is used to introduce a second heat exchange medium for heating the adsorbent in the second downpipe.

[0060] Specifically, as shown in Figures 1 and 3, the preheating section 31 is located above the heating section 32, and the regeneration inlet 34 is connected to the first discharge pipe 311, so that the adsorbent in the adsorption tower 2 enters the first discharge pipe 311 through the adsorbent outlet 24 and the regeneration inlet 34.

[0061] It is understood that the clean air after heat exchange through the heat exchanger 4 and into the heating section 32 is the second heat exchange medium. Within the heating section 32, the second heat exchange medium is used to exchange heat with the adsorbent in the second discharge pipe 321. Optionally, the first medium flow channel 312 communicates with the second medium flow channel 322. The second heat exchange medium after heat exchange within the heating section 32 becomes the first heat exchange medium and is passed into the first medium flow channel 312 to preheat the adsorbent in the first discharge pipe 311, thereby avoiding heat waste.

[0062] Optionally, the heat exchanger 4 includes a shell and heat exchange tubes disposed within the shell. The inner cavity of the shell constitutes a hot-side space communicating with a hot-side inlet 41 and a hot-side outlet 42, and the inner cavity of the heat exchange tubes constitutes a cold-side space communicating with a cold-side inlet 43 and a cold-side outlet 44. In the low-temperature flue gas purification system disclosed herein, the flue gas discharged from the boiler flue and the clean air are exchanged indirectly within the heat exchanger 4 to avoid air pollution.

[0063] It should be noted that the preheating section 31 and the heating section 32 of the flue gas low-temperature purification system disclosed in the present invention both adopt an indirect heat exchange method, which can not only avoid the mutual interference of high-temperature air or water vapor generated by the adsorbent during the cooling process, but also avoid impurities in the air from mixing into the adsorbent and affecting the adsorption effect of the adsorbent.

[0064] Optionally, as shown in Figures 1 to 3, the regeneration tower 3 also includes a cooling section 33 located below the heating section 32. The cooling section 33 is provided with a third discharge pipe 331 and a third medium flow channel 332. The third discharge pipe 331 is used to guide the adsorbent to fall in the cooling section 33. The flue gas outlet 22 of the adsorption tower 2 is connected to the third medium flow channel 332 so that the flue gas discharged from the flue gas outlet 22 of the adsorption tower 2 enters the third medium flow channel 332 to cool the adsorbent in the third discharge pipe 331.

[0065] It can be understood that the adsorbent in the heating section 32 of the flue gas low-temperature purification system disclosed in the present invention can flow to the third discharge pipe 331 after heat exchange and analysis with the high-temperature air. At this time, the adsorbent has a certain temperature. Research has found that if the adsorbent at this temperature flows directly to the adsorption tower 2, the adsorption purification effect on the flue gas is relatively weak. Therefore, the low-temperature clean flue gas is introduced into the cooling section 33 to cool the adsorbent in the third discharge pipe 331, so that the adsorbent can be conveniently used in the adsorption tower 2.

[0066] Optionally, the flue gas low-temperature purification system of the present disclosure further includes a cold recovery component 6 , and at least one of the smoke exhaust port 12 , the smoke outlet 22 and the smoke outlet of the cooling section 33 is connected to the cold recovery component 6 .

[0067] Optionally, as shown in FIG. 1 , the cold recovery component 6 is connected to the smoke exhaust port 12 , the smoke outlet 22 and the smoke outlet of the cooling section 33 .

[0068] That is to say, in the flue gas low-temperature purification system disclosed herein, the cold recovery component 6 can be used to recover the cold in the flue gas discharged from the exhaust port 12, the flue gas outlet 22 and the flue gas discharged from the cooling section 33, thereby avoiding waste of flue gas cold.

[0069] In addition, as shown in Figure 3, the first medium flow channel 312, the second medium flow channel 322 and the third medium flow channel 332 in the flue gas low-temperature purification system disclosed in the present invention are all serpentine flow channels, which ensure the flow time of the heat exchange medium in the first medium flow channel 312, the second medium flow channel 322 and the third medium flow channel 332, thereby improving the heat exchange effect with the adsorbent.

[0070] It should be noted that, as shown in FIG4 , the adsorbent can be filled inside the breathable shell 100 for adsorption. The adsorbent can be a granular or powdered adsorbent, or an adsorbent body made of powder or granular adsorbent, such as a spherical body or a cylinder formed by a powder or granular adsorbent through a binder. Of course, a protective shell can be further formed outside the adsorbent body, such as a breathable membrane covering the outside of the adsorbent body, to improve the strength of the adsorbent body. The breathable shell has air holes, and the flue gas can enter the breathable shell through the air holes. The flue gas can pass through the gaps between adjacent adsorbents and / or the holes of the adsorbent itself, thereby reducing not only direct collisions, friction and wear between adsorbents, but also the generation of dust. The breathable shell can be in the shape of a rotating body such as a sphere or a cylinder, wherein the diameter of the breathable shell 100 is 10mm-100mm, and the diameter of the adsorbent is 1mm-10mm.

[0071] Optionally, the spray cooling tower includes multiple spray components, and the spray tower 1 has multiple spray areas. The multiple spray areas are arranged in sequence along the flue gas flow direction in the spray tower 1. The multiple spray components correspond to the multiple spray areas one by one, and are used to spray and cool the flue gas flowing through the multiple spray areas in sequence to low-temperature flue gas at sub-zero temperature.

[0072] The flue gas low-temperature purification system disclosed herein can utilize multiple spray assemblies to spray and cool different spray areas in the spray tower 1, so that the flue gas in the spray tower 1 is cooled step by step along its flow direction until the flue gas temperature drops below 0°C.

[0073] Optionally, the cold recovery component 6 includes a cold recovery tower 61 and a cold exchanger 62. The cold recovery tower 61 is connected to the smoke exhaust port 12 of the adsorption tower 2 and the cold exchanger 62. The circulating liquid in the cold exchanger 62 exchanges cold with the clean flue gas in the cooling recovery tower to recover the cold in the clean flue gas. The cold exchanger 62 is connected to at least one of the multiple spray areas to indirectly cool the spray liquid discharged from at least one spray area and supply the cooled spray liquid to the spray component corresponding to the at least one spray area.

[0074] It is understandable that the cold exchanger 62 can be connected to one spray zone or multiple spray zones, thereby cooling the spray liquid discharged from the corresponding spray zone. The circulating liquid with cold in the cold exchanger 62 is formed by direct heat exchange between the circulating liquid and the clean flue gas entering the cold recovery tower 61. Two pipelines can be arranged in the cold exchanger 62, one of which is used to pass the circulating liquid after heat exchange (temperature close to 0°C), and the other is used to pass the spray liquid discharged from the spray zone after heat exchange with the flue gas (temperature above 0°C), so that indirect heat exchange can occur in the cold exchanger 62, so that the spray liquid can be used again in the spray zone after heat exchange in the cold exchanger 62, thereby realizing cold recovery and reuse of the flue gas.

[0075] Therefore, the flue gas low-temperature purification system disclosed in the present invention can use the cold recovery component 6 to recover the cold in the flue gas, and can use it again to cool the spray liquid discharged from the spray area, and then pass the cooled spray liquid into its corresponding spray area, thereby realizing the recovery and reuse of cold.

[0076] Optionally, as shown in Figure 1, the multiple spray areas include a first-level spray area 131, a second-level spray area 132, a third-level spray area 133 and a fourth-level spray area 134 arranged in sequence along the flue gas flow direction; the multiple spray components include a first-level spray component 141, a second-level spray component 142, a third-level spray component 143 and a fourth-level spray component 144; the cold exchanger 62 is connected to the spray liquid outlet of the second-level spray area 132 and the spray liquid inlet of the second-level spray component 142.

[0077] That is, the secondary spray assembly 142 cools the flue gas to 30°C-35°C, and the clean flue gas in the adsorption tower 2 cools the spray liquid in the secondary spray zone 132 from 40°C-44°C to 30°C-34°C. Specifically, the clean flue gas in the adsorption tower 2 exchanges heat with the circulating liquid in the cold recovery tower 61 in the cold recovery tower 61, and the circulating liquid after heat exchange is then used to exchange heat with the spray liquid in the secondary spray zone 132 in the cold exchanger 62, so that the spray liquid in the secondary spray zone 132 is cooled from 40°C-44°C to 30°C-34°C.

[0078] It can be understood that after the flue gas enters the spray cooling tower, it flows in a bottom-to-top direction, that is, after the flue gas enters the spray cooling tower, it passes through the first-level spray area 131, the second-level spray area 132, the third-level spray area 133 and the fourth-level spray area 134 in sequence. Since the initial temperature of the flue gas (80℃-100℃) is relatively high, the flue gas can be spray-cooled by using the first-level spray component 141 spray liquid with normal temperature liquid in the first-level spray area 131. At this time, the temperature of the spray liquid in the first-level spray component 141 rises to 50℃-54℃. Since the temperature of the spray liquid is relatively high, it directly exchanges heat with the circulating liquid of the cold recovery tower 61. The heat exchange temperature difference is large, which will lead to poor heat exchange effect and easily cause a certain amount of energy waste. Optionally, the flue gas purification system of the present invention further includes a water cooler, which is connected between the spray liquid outlet of the first-level spray area 131 and the liquid inlet of the first-level spray assembly 141. The spray liquid discharged from the first-level spray area 131 is cooled by the water cooler and then returned to the first-level spray assembly 141.

[0079] In addition, the tertiary spray assembly 143 is provided with a medium-temperature refrigerator 7 for cooling the spray liquid after heat exchange in the tertiary spray area 133 .

[0080] Optionally, the evaporator inlet 53 of the absorption refrigeration machine 5 is connected to the spray liquid outlet of the four-stage spray area 134 , and the evaporator outlet 54 of the absorption refrigeration machine 5 is connected to the spray liquid inlet of the four-stage spray assembly 144 .

[0081] The cooling capacity generated by the absorption refrigerator 5 of the flue gas low-temperature purification system disclosed herein can be used to cool the spray liquid of the four-stage spray assembly 144, thereby avoiding the use of a low-temperature refrigerator and correspondingly reducing the power consumption of the system.

[0082] Therefore, the flue gas low-temperature purification system disclosed in the present invention divides the spray tower 1 into four spray zones, further optimizing the step-by-step cooling effect of the spray tower 1 and avoiding excessive temperature differences between two adjacent spray zones, which would result in excessive cooling capacity being consumed to cool the spray liquid.

[0083] In the description of the present disclosure, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present disclosure and simplifying the description, and do not indicate or imply 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 understood as a limitation to the present disclosure.

[0084] 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 being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. Throughout the present disclosure, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0085] In this disclosure, unless otherwise expressly specified or limited, terms such as "mounted," "connected," "connect," and "fixed" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integration; mechanical connections, electrical connections, or communication between them; direct connections or indirect connections through an intermediate medium; and internal communication between two elements or interaction between two elements, unless otherwise expressly limited. Those skilled in the art will understand the specific meanings of the above terms in this disclosure based on specific circumstances.

[0086] In the present disclosure, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0087] In the present disclosure, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0088] Although the above embodiments have been shown and described, it is understood that the above embodiments are illustrative and are not to be construed as limitations on the present disclosure. Changes, modifications, substitutions and variations of the above embodiments by those skilled in the art are all within the scope of protection of the present disclosure.

Claims

1. A low-temperature flue gas purification system, comprising: A spray tower, the spray tower having a smoke inlet and a smoke exhaust port, the spray tower being used to cool the smoke introduced from the smoke inlet into low-temperature smoke at a sub-zero temperature; an adsorption tower having an adsorbent inlet, an adsorbent outlet, and a flue gas inlet connected to the flue gas outlet, and configured to adsorb and purify the low-temperature flue gas introduced through the flue gas inlet into clean flue gas; a regeneration tower, the regeneration tower comprising a heating section for heating and regenerating an adsorbent therein, the regeneration tower having a regeneration inlet and a regeneration outlet, the regeneration inlet being connected to the adsorbent outlet, and the regeneration outlet being connected to the adsorbent inlet, so that the adsorbent circulates between the adsorption tower and the regeneration tower; a heat exchanger having a hot side inlet and a hot side outlet connected to the boiler flue, a cold side inlet for introducing a heat exchange medium, and a cold side outlet connected to the heating section, wherein the heat exchange medium introduced into the cold side inlet exchanges heat with the flue gas discharged from the boiler flue in the heat exchanger and is then supplied to the heating section; An absorption refrigerator, wherein the generator inlet of the absorption refrigerator is connected to the hot side outlet, the evaporator inlet of the absorption refrigerator is connected to the spray liquid outlet of the spray tower, and the evaporator outlet of the absorption refrigerator is connected to the spray liquid inlet of the spray tower, so as to cool the spray liquid in the evaporator of the absorption refrigerator.

2. The flue gas low-temperature purification system according to claim 1, wherein: The generator outlet of the absorption refrigeration machine is connected to the smoke inlet of the spray tower.

3. The low-temperature flue gas purification system according to claim 2, wherein: The regeneration tower also includes a preheating section located above the heating section, the preheating section having a first downpipe and a first medium flow channel, the heating section having a second downpipe and a second medium flow channel, the first downpipe being used to guide the adsorbent to fall in the preheating section, the second downpipe being used to guide the adsorbent to fall in the heating section, the first medium flow channel being used to introduce a first heat exchange medium for preheating the adsorbent in the first downpipe, and the second medium flow channel being used to introduce a second heat exchange medium for heating the adsorbent in the second downpipe.

4. The low-temperature flue gas purification system according to claim 3, wherein: The regeneration tower also includes a cooling section located below the heating section, and the cooling section is provided with a third discharge pipe and a third medium flow channel. The third discharge pipe is used to guide the adsorbent to fall in the cooling section, and the flue gas outlet of the adsorption tower is connected to the third medium flow channel so that the flue gas discharged from the flue gas outlet of the adsorption tower passes into the third medium flow channel to cool the adsorbent in the third discharge pipe.

5. The low-temperature flue gas purification system according to any one of claims 1 to 4, wherein: The heat exchanger includes a shell and a heat exchange tube arranged in the shell. The inner cavity of the shell constitutes a hot side space connected to the hot side inlet and the hot side outlet, and the inner cavity of the heat exchange tube constitutes a cold side space connected to the cold side inlet and the cold side outlet.

6. The low-temperature flue gas purification system according to any one of claims 1 to 5, wherein: It also includes a cold recovery component, and at least one of the smoke exhaust port, the smoke outlet and the smoke outlet of the cooling section is connected to the cold recovery component.

7. The low-temperature flue gas purification system according to claim 6, wherein: The spray cooling tower includes multiple spray components, and there are multiple spray areas in the spray tower. The multiple spray areas are arranged in sequence along the flue gas flow direction in the spray tower. The multiple spray components correspond to the multiple spray areas one by one, and are used to spray and cool the flue gas flowing through the multiple spray areas in sequence to low-temperature flue gas at sub-zero temperature.

8. The low-temperature flue gas purification system according to claim 7, wherein: The cold recovery component includes a cold recovery tower and a cold exchanger. The cold recovery tower is connected to the smoke exhaust port of the adsorption tower and the cold exchanger. The circulating liquid in the cold exchanger exchanges cold with the clean flue gas in the cooling recovery tower to recover the cold in the clean flue gas. The cold exchanger is connected to at least one of the multiple spray areas to indirectly cool the spray liquid discharged from the at least one spray area and supply the cooled spray liquid to the spray component corresponding to the at least one spray area.

9. The low-temperature flue gas purification system according to claim 8, wherein: The multiple spray areas include a primary spray area, a secondary spray area, a tertiary spray area and a quaternary spray area arranged in sequence along the direction of the flue gas flow; The plurality of spray assemblies include a primary spray assembly, a secondary spray assembly, a tertiary spray assembly and a quaternary spray assembly; The cold exchanger is connected to the spray liquid outlet of the secondary spray zone and the spray liquid inlet of the secondary spray assembly.

10. The low-temperature flue gas purification system according to claim 9, wherein: The evaporator inlet of the absorption refrigeration machine is connected to the spray liquid outlet of the four-stage spraying zone, and the evaporator outlet of the absorption refrigeration machine is connected to the spray liquid inlet of the four-stage spraying assembly.

Images