Flue gas purification system

Abstract

The present invention provides a flue gas purification system, comprising: a washing and drying tower, provided with a first flue gas channel and a first washing channel, the first flue gas channel being arranged inside the washing and drying tower, the first flue gas channel and the first washing channel being interconnected, flue gas being contained in the first flue gas channel, the first washing channel being used to introduce acid liquid, which can wash the flue gas; and a gas cooling tower, provided with a second flue gas channel and a second washing channel, the second flue gas channel being arranged inside the gas cooling tower, the inlet of the second flue gas channel being connected to the outlet of the first flue gas channel, the second flue gas channel and the second washing channel being interconnected, the second washing channel being used to introduce coolant, which can wash the flue gas, thereby reducing the temperature of the flue gas in the second flue gas channel and absorbing moisture in the flue gas. The technical solution provided by the present application can solve the problems of high water consumption and high energy consumption in the prior art of flue gas purification.

Description

Technical Field

[0001] The present invention relates to the technical field of flue gas purification, and in particular to a flue gas purification system. Background Art

[0002] Currently, flue gas purification systems can convert impure flue gas into pure flue gas, which can be used to produce concentrated sulfuric acid. Therefore, the moisture content of the pure flue gas must be strictly controlled. Flue gas purification requires scrubbing with a circulating fluid. This increases the moisture content of the scrubbed flue gas, and the flue gas heats the circulating fluid, causing some of the water in the fluid to evaporate. Later, when removing the moisture from the flue gas, a large amount of cooling water is required to cool the flue gas, condensing the water vapor in the flue gas. This wastes water resources and increases energy consumption. Summary of the Invention

[0003] The present invention provides a flue gas purification system to solve the problems of high water consumption and high energy consumption during flue gas purification in the prior art.

[0004] The present invention provides a flue gas purification system, which includes: a washing and drying tower, wherein a first flue gas channel and a first washing channel are provided on the washing and drying tower, the first flue gas channel is provided inside the washing and drying tower, and the first flue gas channel extends along the bottom of the washing and drying tower to the top of the washing and drying tower, the first flue gas channel and the first washing channel are communicated with each other, there is flue gas in the first flue gas channel, the first washing channel is used to pass acid liquid, and the acid liquid can wash the flue gas to reduce the temperature of the flue gas and absorb moisture in the flue gas; a gas cooling tower, wherein a second flue gas channel and a second washing channel are provided on the gas cooling tower, the second flue gas channel is provided inside the gas cooling tower, and the second flue gas channel extends along the bottom of the gas cooling tower to the top of the gas cooling tower, the inlet of the second flue gas channel is communicated with the outlet of the first flue gas channel, the second flue gas channel and the second washing channel are communicated with each other, the second washing channel is used to pass coolant, and the coolant can wash the flue gas to reduce the temperature of the flue gas in the second flue gas channel and absorb moisture in the flue gas.

[0005] Furthermore, the washing and drying tower has a first discharge port, which is arranged at the bottom of the washing and drying tower, and is used to discharge acid liquid. The washing and drying tower has a first spray pipeline, which is arranged at the top of the washing and drying tower. The first washing channel has a first acid liquid inlet and a first acid liquid outlet arranged opposite to each other, the first acid liquid outlet is connected to the first spray pipeline, and the first acid liquid inlet is connected to the first discharge port.

[0006] Furthermore, a first heat exchanger is provided on the first washing channel. The first heat exchanger has a first pipeline and a second pipeline. The first pipeline is connected to the first washing channel. The first heat exchanger performs heat exchange on the first pipeline through the second pipeline.

[0007] Furthermore, the flue gas purification system also includes: a secondary scrubber, a third flue gas channel and a third washing channel are arranged inside the secondary scrubber, the third flue gas channel is arranged inside the secondary scrubber, and the third flue gas channel extends along the bottom of the secondary scrubber to the top of the secondary scrubber, the inlet of the third flue gas channel is connected with the outlet of the second flue gas channel, the third flue gas channel and the third washing channel are connected with each other, and the third washing channel is used to introduce process water to wash the flue gas in the third flue gas channel; an electrostatic precipitator, having an air inlet and an exhaust port, the air inlet is arranged at the bottom of the electrostatic precipitator, the exhaust port is arranged at the top of the electrostatic precipitator, the air inlet is connected with the outlet of the third flue gas channel, and the exhaust port can discharge the flue gas to remove impurities in the flue gas.

[0008] Furthermore, the flue gas purification system also includes an acid supply part to replenish acid liquid into the first washing channel. The first washing channel is also provided with a first circulation pump and a regulator. The first circulation pump can drive the acid liquid from the first acid liquid inlet to the first acid liquid outlet. The regulator is arranged downstream of the first heat exchanger and is connected to the acid supply part. The regulator can adjust the contact area between the replenished acid liquid and the acid liquid in the first washing channel.

[0009] Furthermore, the first washing channel includes a first circulation pipeline and a first heat exchange pipeline, the first heat exchanger, the first circulation pump and the regulator are arranged on the first circulation pipeline, the first heat exchange pipeline is connected to the first circulation pipeline, the inlet of the first heat exchange pipeline is arranged between the first circulation pump and the first heat exchanger, the outlet of the first heat exchange pipeline is arranged between the first heat exchanger and the regulator, and a first regulating valve is provided on the first heat exchange pipeline.

[0010] Furthermore, the gas cooling tower has a second discharge port, which is arranged at the bottom of the gas cooling tower, and the second discharge port is used to discharge coolant. The gas cooling tower has a second spray pipeline, which is arranged at the top of the gas cooling tower. The second washing channel has a second acid liquid inlet and a second acid liquid outlet arranged oppositely, and the second acid liquid outlet is connected to the second spray pipeline, and the second acid liquid inlet is connected to the second discharge port; the secondary scrubber has a third discharge port, which is arranged at the bottom of the secondary scrubber, and the third discharge port is used to discharge process water. The secondary scrubber has a third spray pipeline, which is arranged at the top of the secondary scrubber, and the third washing channel has a third acid liquid inlet and a third acid liquid outlet arranged oppositely, and the third acid liquid outlet is connected to the third spray pipeline, and the third acid liquid inlet is connected to the third discharge port.

[0011] Furthermore, the second washing channel includes a second circulation pipeline and a second heat exchange pipeline, the second circulation pipeline is provided with a second circulation pump and a second heat exchanger, the second heat exchange pipeline is connected to the second circulation pipeline, the inlet of the second heat exchange pipeline is arranged between the second circulation pump and the second heat exchanger, the outlet of the second heat exchange pipeline is arranged between the second heat exchanger and the second acid liquid outlet, and the second heat exchange pipeline is provided with a second regulating valve; the third washing channel is provided with a third circulation pump to drive the process water from the third acid liquid inlet to the third acid liquid outlet.

[0012] Furthermore, the flue gas purification system also includes a fourth heat exchange pipeline, a third heat exchanger is provided on the fourth heat exchange pipeline, the third heat exchanger includes a third pipeline and a fourth pipeline, the second pipeline and the third pipeline are connected to the fourth heat exchange pipeline, the fourth pipeline is used to connect with the domestic water system, and the third heat exchanger performs heat exchange on the third pipeline through the fourth pipeline.

[0013] Furthermore, a fourth circulation pump and an expansion tank are provided on the fourth heat exchange pipeline. The fourth circulation pump can drive the liquid in the fourth heat exchange pipeline to circulate in the fourth heat exchange pipeline.

[0014] Using the technical solution of the present invention, flue gas first enters the scrubbing and drying tower through the inlet of the first flue gas channel. After being washed with acid in the first scrubbing channel, it is discharged into the gas cooling tower through the outlet of the first flue gas channel and the inlet of the second flue gas channel, where it is then scrubbed with coolant in the second scrubbing channel. With this arrangement, when the acid scrubs the flue gas, the acid cools the flue gas, condensing moisture in the flue gas into the acid, thereby reducing the moisture content in the flue gas. The acid also absorbs acid mist in the flue gas, removing some impurities and effectively scrubbing the flue gas. Furthermore, when the flue gas is scrubbed again in the gas cooling tower, the amount of coolant used can be reduced, avoiding waste of water resources and thus energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0016] Figure 1 A structural schematic diagram of a flue gas purification system provided according to an embodiment of the present invention is shown.

[0017] The above drawings include the following reference numerals:

[0018] 10. Washing and drying tower; 11. First flue gas channel; 121. First circulation pipeline; 1211. First acid liquid inlet; 1212. First acid liquid outlet; 1213. First heat exchanger; 1214. First circulation pump; 1215. Regulator; 122. First heat exchange pipeline; 1221. First regulating valve;

[0019] 20. Gas cooling tower; 21. Second flue gas channel; 22. Second washing channel; 221. Second circulation pipeline; 2211. Second acid liquid inlet; 2212. Second acid liquid outlet; 2213. Second circulation pump; 2214. Second heat exchanger; 222. Second heat exchange pipeline; 2221. Second regulating valve;

[0020] 30. Secondary scrubber; 31. Third flue gas channel; 32. Third scrubbing channel; 321. Third acid liquid inlet; 322. Third acid liquid outlet; 323. Third circulation pump;

[0021] 40. Electric demister; 41. Air inlet; 42. Exhaust port;

[0022] 50. Acid supply department;

[0023] 60. Fourth heat exchange pipeline; 61. Third heat exchanger; 62. Fourth circulation pump; 63. Expansion tank;

[0024] 71. First liquid drain unit; 72. Second liquid drain unit; 73. Smoke supply unit; 74. Water supply unit; 75. Smoke collection unit;

[0025] 80. Water seal structure. DETAILED DESCRIPTION

[0026] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0027] like Figure 1As shown, the present application provides a flue gas purification system, which includes a scrubbing and drying tower 10 and a gas cooling tower 20. The scrubbing and drying tower 10 is provided with a first flue gas channel 11 and a first scrubbing channel. The first flue gas channel 11 is provided inside the scrubbing and drying tower 10 and extends from the bottom of the scrubbing and drying tower 10 to the top of the scrubbing and drying tower 10. The first flue gas channel 11 has an inlet and an outlet that are oppositely arranged. The inlet of the first flue gas channel 11 is provided at the bottom of the scrubbing and drying tower 10, and the outlet of the first flue gas channel 11 is provided at the top of the scrubbing and drying tower 10. The first flue gas channel 11 and the first scrubbing channel are interconnected. Flue gas is contained in the first flue gas channel 11. The first scrubbing channel is used to pass acid liquid, which can scrub the flue gas to reduce the temperature of the flue gas and absorb moisture in the flue gas. The gas cooling tower 20 is provided with a second flue gas channel 21 and a second scrubbing channel 22. The second flue gas channel 21 is disposed within the gas cooling tower 20 and extends from the bottom of the gas cooling tower 20 to the top of the gas cooling tower 20. The second flue gas channel 21 has an inlet and an outlet positioned opposite each other. The inlet of the second flue gas channel 21 is disposed at the bottom of the gas cooling tower 20, and the outlet of the second flue gas channel 21 is disposed at the top of the gas cooling tower 20. The inlet of the second flue gas channel 21 is connected to the outlet of the first flue gas channel 11. The second flue gas channel 21 and the second scrubbing channel 22 are interconnected. The second scrubbing channel 22 is used to pass a coolant, which scrubs the flue gas, thereby reducing the temperature of the flue gas within the second flue gas channel 21 and absorbing moisture from the flue gas.

[0028] Using the technical solution of the present application, the flue gas first enters the washing and drying tower 10 through the inlet of the first flue gas channel 11. After being washed with acid liquid in the first washing channel, the flue gas is discharged into the gas cooling tower 20 through the outlet of the first flue gas channel 11 and the inlet of the second flue gas channel 21, and then washed with coolant in the second washing channel 22. With this arrangement, when the acid liquid washes the flue gas, the acid liquid can cool the flue gas, and the moisture in the flue gas can be condensed into the acid liquid, thereby reducing the moisture content in the flue gas. The acid liquid can also absorb the acid mist in the flue gas and remove some impurities, thereby better washing the flue gas. Furthermore, when the flue gas is passed into the gas cooling tower 20 for further washing, the amount of coolant used can be reduced, avoiding the waste of water resources and thus energy consumption.

[0029] In the present application, the concentration of the acidic liquid circulating within the scrubbing and drying tower 10 is controlled between 50% and 70%, and the saturated vapor pressure of the acidic liquid is relatively low. This configuration facilitates the absorption of moisture from the flue gas. For example, in the present application, the water content of the flue gas entering the scrubbing and drying tower 10 is approximately 18%, while the water content of the flue gas discharged from the scrubbing and drying tower 10 and entering the gas cooling tower 20 is controlled between 12% and 15%, and the water content of the flue gas discharged from the gas cooling tower 20 is controlled at 7%. Alternatively, the acidic liquid may be dilute sulfuric acid.

[0030] In the present application, the temperature of the flue gas entering the washing and drying tower 10 is controlled between 250°C and 350°C, the temperature of the acid solution circulating in the washing and drying tower 10 is controlled between 60°C and 80°C, the temperature of the acid solution exiting the washing and drying tower 10 is controlled between 90°C and 120°C, the temperature of the flue gas exiting the washing and drying tower 10 is controlled between 60°C and 80°C, and the liquid-gas ratio of the acid solution to the flue gas is controlled at 1.0L / m 3 ~5.0L / m 3 With such an arrangement, most of the heat carried by the flue gas is discharged through the acid liquid in the washing and drying tower 10, and the coolant in the gas cooling tower 20 needs to discharge less heat, which can further reduce the amount of cooling water used and reduce energy consumption.

[0031] Specifically, the scrubbing and drying tower 10 has a first discharge port, located at the bottom of the scrubbing and drying tower 10, for discharging acidic liquid. The scrubbing and drying tower 10 also has a first spray line located at the top of the scrubbing and drying tower 10. The first scrubbing channel has a first acidic liquid inlet 1211 and a first acidic liquid outlet 1212, which are oppositely positioned. The first acidic liquid outlet 1212 communicates with the first spray line, and the first acidic liquid inlet 1211 communicates with the first discharge port. Flue gas flows from the bottom of the scrubbing and drying tower 10 to the top of the scrubbing and drying tower 10, while the acidic liquid within the scrubbing and drying tower 10 falls from the top to the bottom of the scrubbing and drying tower 10. This arrangement ensures sufficient contact between the acidic liquid and the flue gas, thereby ensuring the acidic liquid's scrubbing and cooling effects on the flue gas. In this application, the first discharge port is located below the inlet of the first flue gas channel 11, and the first spray line is located below the outlet of the first flue gas channel 11. This arrangement further ensures sufficient contact between the acidic liquid and the flue gas.

[0032] The scrubbing and drying tower 10 is connected to the flue gas supply unit, and untreated flue gas enters the scrubbing and drying tower 10. The flue gas from the scrubbing and drying tower 10 contains a high content of dust and a complex composition, creating the harshest operating environment of any flue gas purification system. The composition of the discharged waste acid is also relatively complex. To ensure the scrubbing and drying tower 10's long-term stable operation, it is constructed from simple, corrosion-resistant, wear-resistant, and non-scaling materials. The tower structure can be either an empty tower or a reverse-spray scrubber.

[0033] Specifically, a first heat exchanger 1213 is provided on the first washing channel. The first heat exchanger 1213 comprises a first pipeline and a second pipeline. The first pipeline communicates with the first washing channel, and the first heat exchanger 1213 exchanges heat with the first pipeline via the second pipeline. This arrangement facilitates lowering the temperature of the acid liquid discharged from the washing and drying tower 10, facilitating its reuse, thereby reducing acid usage and further reducing energy consumption.

[0034] In the present application, since the acid liquid discharged from the washing and drying tower 10 contains a large amount of impurities, has a complex composition, is corrosive, and is prone to scaling when the temperature drops, the diameter of the first pipe is larger than the diameter of the second pipe to avoid blockage in the first pipe and thus ensure the normal operation of the first heat exchanger 1213. The material of the first heat exchanger 1213 can be a corrosion-resistant and wear-resistant alloy material or fluorine-resistant glass, and the first heat exchanger 1213 can adopt a plate structure, a tube-in-tube structure, etc.

[0035] The flue gas purification system further includes a secondary scrubber 30 and an electrostatic precipitator 40. A third flue gas channel 31 and a third scrubbing channel 32 are disposed within the secondary scrubber 30. The third flue gas channel 31 is disposed within the secondary scrubber 30 and extends from the bottom to the top of the secondary scrubber 30. The third flue gas channel 31 has an inlet and an outlet positioned opposite each other. The inlet of the third flue gas channel 31 is disposed at the bottom of the secondary scrubber 30, while the outlet is disposed at the top of the secondary scrubber 30. The inlet of the third flue gas channel 31 communicates with the outlet of the second flue gas channel 21, and the third flue gas channel 31 and the third scrubbing channel 32 are interconnected. The third scrubbing channel 32 is used to introduce process water to scrub the flue gas within the third flue gas channel 31. The flue gas is discharged into the secondary scrubber 30 through the outlet of the second flue gas channel 21 and the inlet of the third flue gas channel 31. The process water can further scrub the flue gas, removing dust or acid mist from the flue gas.

[0036] The temperature of the process water is the same as the temperature of the flue gas in the third flue gas channel 31 , so the process water will not increase the moisture content in the flue gas. The moisture content of the flue gas discharged from the secondary scrubber 30 is 7%.

[0037] Specifically, the electrostatic precipitator 40 has an air inlet 41 and an exhaust port 42. The air inlet 41 is located at the bottom of the electrostatic precipitator 40, and the exhaust port 42 is located at the top of the electrostatic precipitator 40. The air inlet 41 is connected to the outlet of the third flue gas channel 31, and the exhaust port 42 can discharge flue gas to remove impurities in the flue gas. This configuration can further remove dust and acid mist from the flue gas, improving the cleanliness of the flue gas. The flue gas discharged from the exhaust port 42 is clean flue gas and can be used for the subsequent production of concentrated sulfuric acid.

[0038] Furthermore, the flue gas purification system further includes a flue gas collecting portion 75 , and the exhaust port 42 is in communication with the flue gas collecting portion 75 for collecting the cleaned flue gas to facilitate subsequent work.

[0039] Among them, the flue gas purification system also includes a water seal structure 80, which is connected to the exhaust port 42. When the flue gas purification system is working normally, the water seal structure 80 can prevent external gas from entering the flue gas purification system. When an error occurs in the operation of the flue gas purification system, a negative pressure state is easily generated in the flue gas purification system. The flue gas purification system can absorb the water in the water seal structure 80 into the flue gas purification system, and then the outside air can enter the flue gas purification system to avoid damage to the flue gas purification system.

[0040] Furthermore, the flue gas purification system also includes an acid supply unit 50 to replenish acid liquid into the first washing channel. The first washing channel is also provided with a first circulation pump 1214 and a regulator 1215. The first circulation pump 1214 can drive the acid liquid from the first acid liquid inlet 1211 to the first acid liquid outlet 1212. The regulator 1215 is arranged downstream of the first heat exchanger 1213. The regulator 1215 is connected to the acid supply unit 50. The regulator 1215 can adjust the contact area between the replenished acid liquid and the acid liquid in the first washing channel. When the moisture in the flue gas condenses into the acid liquid, the concentration of the acid liquid will decrease. In order to ensure the concentration of the acid liquid, it is necessary to replenish the first washing channel with a higher concentration of acid liquid. In the present application, the acid liquid in the acid supply unit 50 is concentrated sulfuric acid. However, a high concentration of acid liquid will release a large amount of heat when it comes into contact with water. The regulator 1215 can reduce the heat released.

[0041] In this application, regulator 1215 includes multiple nozzles, which can increase the contact area between the replenished acid solution and the acid solution in the first washing channel, thereby reducing heat generation. In this application, regulator 1215 can control the temperature of the acid solution before and after mixing within a range of 1°C to 5°C. Concentration regulator 1215 is constructed from a material that is resistant to extreme temperature fluctuations, corrosion, and wear.

[0042] Furthermore, the flue gas purification system also includes a first drain portion 71, and the first washing channel is connected to the first drain portion 71. When the moisture in the flue gas condenses into the acid liquid, the content of the acid liquid increases, and the excess acid liquid in the washing and drying tower 10 can be discharged to the first drain portion 71 through the first washing channel.

[0043] Specifically, the first washing channel includes a first circulation pipeline 121 and a first heat exchange pipeline 122. A first heat exchanger 1213, a first circulation pump 1214, and a regulator 1215 are disposed on the first circulation pipeline 121. The first heat exchange pipeline 122 is in communication with the first circulation pipeline 121. The inlet of the first heat exchange pipeline 122 is disposed between the first circulation pump 1214 and the first heat exchanger 1213, and the outlet of the first heat exchange pipeline 122 is disposed between the first heat exchanger 1213 and the regulator 1215. A first regulating valve 1221 is disposed on the first heat exchange pipeline 122. With this arrangement, the temperature of the acid solution in the first washing channel can be controlled by adjusting the opening of the first regulating valve 1221, thereby facilitating temperature control of the acid solution.

[0044] Furthermore, the gas cooling tower 20 has a second discharge port, located at the bottom of the gas cooling tower 20, for discharging coolant. The gas cooling tower 20 has a second spray line located at the top of the gas cooling tower 20. The second scrubbing channel 22 has a second acid liquid inlet 2211 and a second acid liquid outlet 2212 located opposite each other. The second acid liquid outlet 2212 communicates with the second spray line, and the second acid liquid inlet 2211 communicates with the second discharge port. Flue gas flows from the bottom of the gas cooling tower 20 to the top of the gas cooling tower 20, while the coolant within the gas cooling tower 20 falls from the top to the bottom of the gas cooling tower 20. This arrangement ensures sufficient contact between the coolant and the flue gas, thereby ensuring the coolant's scrubbing and cooling effect on the flue gas. In the present application, the second discharge port is located below the inlet of the second flue gas channel 21, and the second spray line is located below the outlet of the second flue gas channel 21. This arrangement further ensures sufficient contact between the coolant and the flue gas.

[0045] Specifically, the flue gas purification system also includes a second drain portion 72, and the second washing channel 22 is connected to the second drain portion 72. When the moisture in the flue gas condenses into the coolant, the content of the coolant increases, and the excess coolant in the gas cooling tower 20 can be discharged to the second drain portion 72 through the second washing channel 22.

[0046] The secondary scrubber 30 has a third discharge port located at the bottom of the scrubber 30 for discharging process water. A third spray line is located at the top of the scrubber 30. The third scrubbing channel 32 has a third acid liquid inlet 321 and a third acid liquid outlet 322, which are oppositely positioned. The third acid liquid outlet 322 communicates with the third spray line, and the third acid liquid inlet 321 communicates with the third discharge port. Flue gas flows from the bottom of the secondary scrubber 30 to the top, while process water within the scrubber 30 falls from the top to the bottom. This arrangement ensures sufficient contact between the process water and the flue gas, thereby ensuring both the scrubbing and cooling effects of the process water on the flue gas. In this application, the third discharge port is located below the inlet of the third flue gas channel 31, and the third spray line is located below the outlet of the third flue gas channel 31. This arrangement further ensures sufficient contact between the process water and the flue gas.

[0047] Among them, the flue gas purification system also includes a water supply part 74, which is connected to the bottom of the secondary scrubber 30. The water supply part 74 can replenish process water for the secondary scrubber 30, and there is a connecting pipeline between the secondary scrubber 30 and the gas cooling tower 20. The connecting pipeline can replenish excess process water in the secondary scrubber 30 to the gas cooling tower 20. Since the process water is still relatively clean after washing the flue gas, direct discharge will cause waste of process water, so the process water in the secondary scrubber 30 is replenished to the gas cooling tower 20.

[0048] Specifically, the second washing channel 22 includes a second circulation line 221 and a second heat exchange line 222. A second circulation pump 2213 and a second heat exchanger 2214 are provided on the second circulation line 221. The second heat exchange line 222 communicates with the second circulation line 221. The inlet of the second heat exchange line 222 is located between the second circulation pump 2213 and the second heat exchanger 2214, and the outlet of the second heat exchange line 222 is located between the second heat exchanger 2214 and the second acid outlet 2212. A second regulating valve 2221 is provided on the second heat exchange line 222. A third circulation pump 323 is provided on the third washing channel 32 to drive process water from the third acid inlet 321 to the third acid outlet 322. This arrangement allows the temperature of the coolant in the second washing channel 22 to be controlled by adjusting the opening of the second regulating valve 2221, thereby facilitating temperature control of the coolant. The second circulation pump 2213 is convenient for driving the coolant to flow in the second washing channel 22 , and the third circulation pump 323 is convenient for driving the process water to flow in the third washing channel 32 .

[0049] Furthermore, the flue gas purification system includes a fourth heat exchange pipeline 60, which is a closed-loop circulation pipeline. A third heat exchanger 61 is installed on the fourth heat exchange pipeline 60. The third heat exchanger 61 includes a third pipeline and a fourth pipeline. The second pipeline and the third pipeline are connected to the fourth heat exchange pipeline 60. The fourth pipeline is used to connect to the domestic water system. The third heat exchanger 61 exchanges heat with the third pipeline through the fourth pipeline. This arrangement can recover heat from the acid solution and utilize the heat, reducing heat loss.

[0050] In addition, the liquid in the fourth heat exchange pipeline 60 is softened water, and the liquid in the domestic water system is ordinary domestic water. If the domestic water system is directly connected to the second pipeline, scaling is very likely to form in the second pipeline and the domestic water system, which may cause the first heat exchanger 1213 and the pipeline in the domestic water system to be easily blocked, thereby affecting the normal operation of the heat exchange. However, the above structure can avoid the structure in the fourth heat exchange pipeline 60 and ensure the normal operation of the heat exchange.

[0051] At the same time, if the domestic water system is directly connected to the second pipeline, when the first heat exchanger 1213 leaks, the entire domestic water system will be damaged. However, by adopting the above structure, only the fourth heat exchange pipeline 60 will be damaged, which is convenient for maintenance and reduces the scope of damage.

[0052] In this application, the heat recovery rate of the flue gas purification system is about 60% to 80%.

[0053] Specifically, the fourth heat exchange pipeline 60 is further provided with a fourth circulation pump 62 and an expansion tank 63. The fourth circulation pump 62 can drive the liquid in the fourth heat exchange pipeline 60 to circulate within the fourth heat exchange pipeline 60. This configuration facilitates driving the liquid in the fourth heat exchange pipeline 60 to flow. The liquid in the fourth heat exchange pipeline 60 expands and contracts due to heat and cold, causing the volume of the liquid to change. The expansion tank 63 can accommodate excess liquid to prevent the fourth heat exchange pipeline 60 from rupturing.

[0054] Furthermore, the fourth heat exchange pipeline 60 is provided with a temperature detector, a pressure detection alarm device, a pH detection alarm device, etc., so as to detect the working status of the fourth heat exchange pipeline 60.

[0055] Among them, liquid level detectors are provided at the bottom of the washing and drying tower 10, the bottom of the gas cooling tower 20 and the bottom of the gas cooling tower 20 to detect the liquid levels of the washing and drying tower 10, the gas cooling tower 20 and the gas cooling tower 20; a temperature detector is provided on the connecting pipe between the outlet of the first flue gas channel 11 and the inlet of the second flue gas channel 21 to detect the temperature of the flue gas discharged from the washing and drying tower 10; temperature detectors are provided on the first washing channel and the second washing channel 22 to detect the temperature of the acid liquid and the coolant; a concentration detector is provided on the first washing channel to detect the concentration of the acid liquid; a flow detector is provided on the connecting pipe between the water supply part 74 and the secondary scrubber 30 to detect the flow of process water entering the secondary scrubber 30.

[0056] In order to better understand the technical solution of the present application, the flue gas purification system in the prior art is compared with the flue gas purification system of the present application. The flue gas volume entering the flue gas purification system is 156300Nm 3 / h, moisture content 18.5%, temperature 280℃:

[0057]

[0058] It can be concluded from the above table that the flow rate of the liquid flowing through the second circulation pump 2213 is less than the flow rate of the circulation pump flowing through the gas cooling tower 20. It can be concluded that the use of the flue gas purification system in this application can reduce the use of coolant, avoid waste of water resources, and thus avoid energy consumption.

[0059] In addition, the concentration of the acid solution entering the washing and drying tower 10 in the flue gas purification system of the present application is 50%, the temperature is 70°C, and the liquid-gas ratio is 3L / m 3 Theoretically calculated, the temperature of the acid liquid discharged from the washing and drying tower 10 is 109° C. The recoverable heat in the flue gas purification system is 71.6%.

[0060] In this application, the waste acid discharge includes two parts: one part is discharged from the washing and drying tower 10, about 10m 3 / h, with a concentration of about 50%, complex components and relatively dirty; the other part is discharged from the gas cooling tower 20, about 8m 3 / h, the acid concentration is low, the impurities are mainly halogen elements, and it is relatively clear. In the existing technology, the waste acid discharge volume is about 34m 3 / h, the acid concentration is low, about 8%, the composition is complex and dirty. The flue gas purification system of the present application can reduce the discharge of waste acid and realize the separation of clean and dirty water, which is convenient for the recovery and treatment of waste acid.

[0061] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0062] Unless otherwise specifically stated, the relative arrangement of the parts and steps, the numerical expressions and the numerical values set forth in these embodiments do not limit the scope of the present invention. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. The techniques, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the techniques, methods and equipment should be considered as part of the authorization specification. In all examples shown and discussed here, any specific values should be interpreted as being merely exemplary and not as limiting. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following figures, and therefore, once an item is defined in one figure, it does not need to be further discussed in subsequent figures.

[0063] In the description of the present invention, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "horizontal, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention; the directional words "inside and outside" refer to the inside and outside relative to the outline of each component itself.

[0064] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used herein to describe the spatial positional relationship of a device or feature to other devices or features as shown in the figures. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figures. For example, if the device in the drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0065] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0066] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A flue gas purification system, characterized in that: The flue gas purification system comprises: A washing and drying tower (10), wherein the washing and drying tower (10) is provided with a first flue gas channel (11) and a first washing channel, wherein the first flue gas channel (11) is provided inside the washing and drying tower (10), and the first flue gas channel (11) extends along the bottom of the washing and drying tower (10) to the top of the washing and drying tower (10), the first flue gas channel (11) and the first washing channel are communicated with each other, flue gas is present in the first flue gas channel (11), and the first washing channel is used to pass acid liquid, and the acid liquid can wash the flue gas to reduce the temperature of the flue gas and absorb moisture in the flue gas; A gas cooling tower (20), wherein the gas cooling tower (20) is provided with a second flue gas channel (21) and a second washing channel (22), the second flue gas channel (21) is provided inside the gas cooling tower (20), and the second flue gas channel (21) extends along the bottom of the gas cooling tower (20) to the top of the gas cooling tower (20), the inlet of the second flue gas channel (21) is communicated with the outlet of the first flue gas channel (11), the second flue gas channel (21) and the second washing channel (22) are communicated with each other, and the second washing channel (22) is used for passing a cooling liquid, and the cooling liquid can wash the flue gas to reduce the temperature of the flue gas in the second flue gas channel (21) and absorb moisture in the flue gas; The washing and drying tower (10) has a first discharge port, which is arranged at the bottom of the washing and drying tower (10) and is used to discharge acid liquid. The washing and drying tower (10) has a first spray pipeline, which is arranged at the top of the washing and drying tower (10). The first washing channel has a first acid liquid inlet (1211) and a first acid liquid outlet (1212) which are arranged opposite to each other. The first acid liquid outlet (1212) is connected to the first spray pipeline, and the first acid liquid inlet (1211) is connected to the first discharge port. A first heat exchanger (1213) is provided on the first washing channel, the first heat exchanger (1213) having a first pipeline and a second pipeline, the first pipeline being in communication with the first washing channel, and the first heat exchanger (1213) performing heat exchange on the first pipeline through the second pipeline; The flue gas purification system further comprises an acid supply unit (50) for replenishing acid liquid into the first washing channel. The first washing channel is further provided with a first circulation pump (1214) and a regulator (1215). The first circulation pump (1214) is capable of driving the acid liquid from the first acid liquid inlet (1211) to the first acid liquid outlet (1212). The regulator (1215) is provided downstream of the first heat exchanger (1213). The regulator (1215) is in communication with the acid supply unit (50). The regulator (1215) is capable of adjusting the contact area between the replenished acid liquid and the acid liquid in the first washing channel. The first washing channel comprises a first circulation pipeline (121) and a first heat exchange pipeline (122); the first heat exchanger (1213), the first circulation pump (1214) and the regulator (1215) are arranged on the first circulation pipeline (121); the first heat exchange pipeline (122) is in communication with the first circulation pipeline (121); the inlet of the first heat exchange pipeline (122) is arranged between the first circulation pump (1214) and the first heat exchanger (1213); the outlet of the first heat exchange pipeline (122) is arranged between the first heat exchanger (1213) and the regulator (1215); and a first regulating valve (1221) is provided on the first heat exchange pipeline (122); The flue gas purification system further comprises a fourth heat exchange pipeline (60), a third heat exchanger (61) is provided on the fourth heat exchange pipeline (60), the third heat exchanger (61) comprises a third pipeline and a fourth pipeline, the second pipeline and the third pipeline are in communication with the fourth heat exchange pipeline (60), the fourth pipeline is used to be in communication with a domestic water system, and the third heat exchanger (61) performs heat exchange on the third pipeline through the fourth pipeline.

2. The flue gas purification system according to claim 1, characterized in that: The flue gas purification system further comprises: A secondary scrubber (30), wherein a third flue gas channel (31) and a third washing channel (32) are provided in the secondary scrubber (30), wherein the third flue gas channel (31) is provided inside the secondary scrubber (30), and the third flue gas channel (31) extends along the bottom of the secondary scrubber (30) to the top of the secondary scrubber (30), wherein the inlet of the third flue gas channel (31) is communicated with the outlet of the second flue gas channel (21), and the third flue gas channel (31) and the third washing channel (32) are communicated with each other, and the third washing channel (32) is used for introducing process water to wash the flue gas in the third flue gas channel (31); The electric precipitator (40) has an air inlet (41) and an exhaust port (42), wherein the air inlet (41) is arranged at the bottom of the electric precipitator (40), and the exhaust port (42) is arranged at the top of the electric precipitator (40), the air inlet (41) is connected to the outlet of the third flue gas channel (31), and the exhaust port (42) can discharge the flue gas to remove impurities in the flue gas.

3. The flue gas purification system according to claim 2, characterized in that: The gas cooling tower (20) has a second discharge port, which is arranged at the bottom of the gas cooling tower (20) and is used to discharge cooling liquid. The gas cooling tower (20) has a second spray pipeline, which is arranged at the top of the gas cooling tower (20). The second washing channel (22) has a second acid liquid inlet (2211) and a second acid liquid outlet (2212) which are arranged opposite to each other. The second acid liquid outlet (2212) is connected to the second spray pipeline, and the second acid liquid inlet (2211) is connected to the second discharge port. The secondary washer (30) has a third discharge port, which is arranged at the bottom of the secondary washer (30) and is used to discharge process water. The secondary washer (30) has a third spray pipeline, which is arranged at the top of the secondary washer (30). The third washing channel (32) has a third acid liquid inlet (321) and a third acid liquid outlet (322) which are arranged opposite to each other. The third acid liquid outlet (322) is communicated with the third spray pipeline, and the third acid liquid inlet (321) is communicated with the third discharge port.

4. The flue gas purification system according to claim 3, characterized in that: The second washing channel (22) comprises a second circulation pipeline (221) and a second heat exchange pipeline (222); the second circulation pipeline (221) is provided with a second circulation pump (2213) and a second heat exchanger (2214); the second heat exchange pipeline (222) is in communication with the second circulation pipeline (221); the inlet of the second heat exchange pipeline (222) is provided between the second circulation pump (2213) and the second heat exchanger (2214); the outlet of the second heat exchange pipeline (222) is provided between the second heat exchanger (2214) and the second acid liquid outlet (2212); and the second heat exchange pipeline (222) is provided with a second regulating valve (2221); The third washing channel (32) is provided with a third circulation pump (323) to drive the process water from the third acid solution inlet (321) to the third acid solution outlet (322).

5. The flue gas purification system according to claim 1, characterized in that: The fourth heat exchange pipeline (60) is further provided with a fourth circulation pump (62) and an expansion tank (63). The fourth circulation pump (62) is capable of driving the liquid in the fourth heat exchange pipeline (60) to circulate in the fourth heat exchange pipeline (60).

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