Flue gas multi-pollutant ultra-clean emission treatment system

Abstract

The invention discloses a flue gas multi-pollutant ultra-clean emission treatment system. The flue gas multi-pollutant ultra-clean emission treatment system comprises a desulfurization device, a flue gas purification device and a flue gas purification device, a demister; a carbon-based catalyst is arranged in the purification tower; the first-stage heat exchanger comprises a first heat exchange flow path and a second heat exchange flow path which exchange heat with each other, an inlet of the first heat exchange flow path is communicated with an outlet of the desulfurization device, an outlet of the first heat exchange flow path is communicated with an inlet of the second-stage heat exchanger, and an outlet of the second-stage heat exchanger is communicated with an inlet of the demister; an inlet of the second heat exchange flow path is communicated with an outlet of the demister, and an outlet of the second heat exchange flow path is communicated with an inlet of the purification tower. According to the flue gas multi-pollutant ultra-clean emission treatment system disclosed by the invention, the flue gas entering the purification tower has lower moisture content and more suitable temperature, the adverse effect of the high-humidity flue gas on a carbon-based catalyst purification process is reduced, and deep ultra-clean treatment of multiple pollutants is favorably realized.

Description

Technical Field

[0001] This invention relates to the field of flue gas treatment technology, and in particular to a flue gas multi-pollutant ultra-clean emission treatment system. Background Technology

[0002] Carbon-based catalytic flue gas purification technology is a treatment technology that utilizes carbon-based catalysts to synergistically remove multiple pollutants from flue gas. In this technology, SO2 in the flue gas can be removed through adsorption and catalysis by the carbon-based catalyst, while NOx in the flue gas can undergo a reduction reaction in the presence of ammonia under the action of the carbon-based catalyst, thereby achieving denitrification. The carbon-based catalyst used for flue gas treatment can also be regenerated and recycled. Therefore, carbon-based catalytic methods have a good foundation for application in the field of deep flue gas purification.

[0003] With increasingly stringent requirements for pollutant emission control, existing industrial plants are placing higher demands on their flue gas deep purification capabilities. Flue gas from wet desulfurization units typically exhibits low temperature and high moisture content, sometimes even approaching saturated wet flue gas. If this type of flue gas directly enters subsequent purification equipment, the high humidity can negatively impact the purification process of carbon-based catalysts; furthermore, the low flue gas temperature is detrimental to the stable operation of subsequent deep pollutant removal processes. Although carbon-based catalysts can adsorb and catalyze various pollutants in flue gas at low temperatures, the presence of water vapor still affects their purification performance.

[0004] In existing technologies, the scheme of directly setting up purification equipment at the downstream end of a wet desulfurization unit usually cannot meet the needs of flue gas dehumidification and temperature adjustment at the same time. This results in the flue gas entering the purification unit still being in a high humidity and low temperature state, which in turn affects the subsequent purification effect. Summary of the Invention

[0005] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a multi-pollutant ultra-clean emission treatment system for flue gas, which achieves lower moisture content and more suitable temperature for the flue gas entering the purification tower, reduces the adverse effects of high-humidity flue gas on the purification process of carbon-based catalysts, and facilitates the deep ultra-clean treatment of multiple pollutants.

[0006] According to an embodiment of the present invention, a multi-pollutant ultra-clean emission treatment system for flue gas includes: a desulfurization device; a demister; a purification tower, wherein a carbon-based catalyst is disposed in the purification tower; a primary heat exchanger and a secondary heat exchanger; the primary heat exchanger includes a first heat exchange path and a second heat exchange path that exchange heat with each other; the inlet of the first heat exchange path is connected to the outlet of the desulfurization device; the outlet of the first heat exchange path is connected to the inlet of the secondary heat exchanger; the outlet of the secondary heat exchanger is connected to the inlet of the demister; the inlet of the second heat exchange path is connected to the outlet of the demister; and the outlet of the second heat exchange path is connected to the inlet of the purification tower.

[0007] According to an embodiment of the present invention, the flue gas multi-pollutant ultra-clean emission treatment system includes a carbon-based catalyst in the purification tower. The primary heat exchanger includes a first heat exchange flow path and a second heat exchange flow path that exchange heat with each other. The inlet of the first heat exchange flow path is connected to the outlet of the desulfurization device, the outlet of the first heat exchange flow path is connected to the inlet of the secondary heat exchanger, the outlet of the secondary heat exchanger is connected to the inlet of the demister, the inlet of the second heat exchange flow path is connected to the outlet of the demister, and the outlet of the second heat exchange flow path is connected to the inlet of the purification tower. By passing the desulfurized high-humidity flue gas sequentially through the primary heat exchanger, the secondary heat exchanger, and the demister for dehumidification, and then returning it to the primary heat exchanger for reheating before sending it into the purification tower, the flue gas entering the purification tower has a lower moisture content and a more suitable temperature, reducing the adverse effects of high-humidity flue gas on the purification process of the carbon-based catalyst, and facilitating the deep ultra-clean treatment of multiple pollutants.

[0008] In some embodiments of the present invention, the primary heat exchanger and the secondary heat exchanger are integrated into a cooling tower; or, the primary heat exchanger and the secondary heat exchanger are separate components.

[0009] In some embodiments of the present invention, an ammonia injection device is further included, which is connected in series between the outlet of the second heat exchange flow path and the inlet of the purification tower for supplying ammonia to the flue gas.

[0010] In some embodiments of the present invention, a heater is further included, which is connected in series between the outlet of the second heat exchange path and the inlet of the ammonia injection device for heating the flue gas.

[0011] In some embodiments of the present invention, the purification tower is provided with a purification tower catalyst outlet, and further includes: a boiler, the flue gas outlet of the boiler being connected to the inlet of the desulfurization device; and a regeneration tower, the regeneration tower being provided with a catalyst inlet and a regeneration gas outlet, the catalyst inlet being connected to the purification tower catalyst outlet, the regeneration tower being used to heat, regenerate, and cool the carbon-based catalyst that is saturated with adsorption in the purification tower, and the regeneration gas outlet being connected to the inlet of the desulfurization device and / or the furnace of the boiler.

[0012] In some embodiments of the present invention, the regeneration tower is provided with a cooling unit having an air inlet and an air outlet, and further includes a cooling fan connected to the air inlet for providing cold air to the cooling unit, and the air outlet connected to the primary air system and / or secondary air system of the boiler.

[0013] In some embodiments of the present invention, the regeneration tower is provided with a regeneration tower catalyst outlet and further includes: a vibrating screen, the inlet of which is connected to the regeneration tower catalyst outlet, and the outlet of which is connected to the purification tower and the boiler respectively. The vibrating screen is used to screen the regenerated carbon-based catalyst and return the carbon-based catalyst with a particle size greater than or equal to a preset value to the purification tower, and transport the carbon-based catalyst with a particle size less than the preset value to the boiler.

[0014] In some embodiments of the present invention, the primary heat exchanger is provided with a first condensate outlet for discharging condensate formed during the flue gas cooling process; and / or, the secondary heat exchanger is provided with a second condensate outlet for discharging condensate formed during the flue gas cooling process.

[0015] In some embodiments of the present invention, the desulfurization device is a wet desulfurization device, and the first condensate outlet and / or the second condensate outlet are connected to the water inlet of the wet desulfurization device.

[0016] In some embodiments of the present invention, the secondary heat exchanger includes a third heat exchange path and a fourth heat exchange path that exchange heat with each other. The inlet of the third heat exchange path is connected to the outlet of the first heat exchange path, and the outlet of the third heat exchange path is connected to the inlet of the demister. The fourth heat exchange path is internally circulated with refrigerant for cooling the flue gas in the third heat exchange path. The refrigerant is ambient air or cooling water.

[0017] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0018] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a schematic diagram of a flue gas multi-pollutant ultra-clean emission treatment system according to an embodiment of the present invention; Figure 2 This is a schematic diagram of a flue gas multi-pollutant ultra-clean emission treatment system according to another embodiment of the present invention; Figure 3 This is a schematic diagram of a flue gas multi-pollutant ultra-clean emission treatment system according to another embodiment of the present invention.

[0019] Figure label: 100. Ultra-clean emission treatment system for multiple pollutants in flue gas; 1. Desulfurization unit; 2. Demister; 3. Purification tower; 40. Cooling tower; 41. Primary heat exchanger; 411. First condensate outlet; 42. Secondary heat exchanger; 421. Second condensate outlet; 5. Ammonia injection device; 6. Heater; 71. Boiler; 72. Blower; 8. Regeneration tower; 91. Cooling fan; 92. Vibrating screen; 93. Powder maker; 94. Dust collector; 95. Chimney. Detailed Implementation

[0020] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0021] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, features defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more. In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0022] The following description, with reference to the accompanying drawings, describes an embodiment of a flue gas multi-pollutant ultra-clean emission treatment system 100.

[0023] like Figures 1-3 As shown, the flue gas multi-pollutant ultra-clean emission treatment system 100 according to an embodiment of the present invention includes a desulfurization device 1, a demister 2, a purification tower 3, a primary heat exchanger 41, and a secondary heat exchanger 42. The purification tower 3 contains a carbon-based catalyst. The primary heat exchanger 41 includes a first heat exchange path and a second heat exchange path that exchange heat with each other. The inlet of the first heat exchange path is connected to the outlet of the desulfurization device 1, the outlet of the first heat exchange path is connected to the inlet of the secondary heat exchanger 42, the outlet of the secondary heat exchanger 42 is connected to the inlet of the demister 2, the inlet of the second heat exchange path is connected to the outlet of the demister 2, and the outlet of the second heat exchange path is connected to the inlet of the purification tower 3.

[0024] Understandably, before entering the purification tower 3, the flue gas passes sequentially through the desulfurization device 1, the first heat exchange path of the primary heat exchanger 41, the secondary heat exchanger 42, and the demister 2, and then returns to the second heat exchange path of the primary heat exchanger 41. The desulfurized flue gas first flows along the first heat exchange path, completing the first stage of heat exchange before entering the secondary heat exchanger 42 and the demister 2. After being treated by the secondary heat exchanger 42 and the demister 2, the flue gas then flows along the second heat exchange path, completing the second stage of heat exchange before entering the purification tower 3, thereby reducing the temperature and moisture content of the flue gas before entering the purification tower 3.

[0025] Specifically, the flue gas discharged from desulfurization unit 1 typically has a low temperature and high moisture content. This flue gas first flows in the first heat exchange path of primary heat exchanger 41, and then enters secondary heat exchanger 42 for further heat exchange, making it easier for some of the moisture in the flue gas to precipitate. Subsequently, the flue gas enters demister 2, which further removes mist droplets from the flue gas. After being treated by secondary heat exchanger 42 and demister 2, the flue gas has a relatively lower moisture content. When it enters the second heat exchange path of primary heat exchanger 41, it can absorb heat from the flue gas in the first heat exchange path. In this way, the flue gas before entering purification tower 3 has a lower moisture content and a slightly higher temperature, and its relative humidity also decreases, making it more suitable for contacting the carbon-based catalyst in purification tower 3 and completing the subsequent purification process.

[0026] Therefore, the flue gas multi-pollutant ultra-clean emission treatment system 100 of this application does not simply connect multiple treatment units in series, but rather utilizes the first and second heat exchange paths in the primary heat exchanger 41 to form a series of interconnected heat exchange paths. The flue gas from the outlet of the desulfurization unit 1 first enters the first heat exchange path of the primary heat exchanger 41, where it exchanges heat with the flue gas in the second heat exchange path before entering the secondary heat exchanger 42. After further heat exchange in the secondary heat exchanger 42, the flue gas enters the demister 2, where liquid droplets and mist entrained in the flue gas are separated. The flue gas treated by the demister 2 then enters the second heat exchange path of the primary heat exchanger 41, where it completes heat exchange before entering the purification tower 3, where it contacts the carbon-based catalyst installed in the purification tower 3 for further purification of the pollutants in the flue gas.

[0027] In actual operation, boiler 71 can serve as an upstream flue gas source, and blower 72 is connected to boiler 71 to supply combustion air to boiler 71. The flue gas discharged from boiler 71 first enters dust collector 94, which removes some particulate matter from the flue gas. Then, the flue gas enters desulfurization unit 1, which first desulfurizes the flue gas. The desulfurized flue gas enters the first heat exchange path of primary heat exchanger 41 through the outlet of desulfurization unit 1, where it exchanges heat with the flue gas in the second heat exchange path. After completing the initial heat exchange, the flue gas enters secondary heat exchanger 42, where it continues to exchange heat before entering demister 2. After the demister 2 removes the mist droplets, the flue gas enters the second heat exchange path of primary heat exchanger 41, where it absorbs heat from the flue gas in the first heat exchange path before entering purification tower 3. The carbon-based catalyst installed inside purification tower 3 can fully contact the flue gas to purify various pollutants in the flue gas. As a result, the temperature and moisture content of the flue gas have been reduced before it enters purification tower 3, which can mitigate the adverse effects on the purification process caused by high-humidity flue gas directly entering purification tower 3.

[0028] In some embodiments, the flue gas purified by the purification tower 3 can be discharged through the chimney 95.

[0029] In some embodiments, the flue gas multi-pollutant ultra-clean emission treatment system 100 can be installed downstream of existing production units and existing desulfurization units 1 to further purify the flue gas after desulfurization. Especially when the desulfurization unit 1 is a wet desulfurization unit, its outlet flue gas is usually at a low temperature and has a high moisture content. The flue gas multi-pollutant ultra-clean emission treatment system 100 performs staged cooling, demisting, and heat recovery treatment on the flue gas through a path consisting of a primary heat exchanger 41, a secondary heat exchanger 42, and a demister 2, so that the flue gas before entering the purification tower 3 is transformed from a high-humidity state to an unsaturated state that is more suitable for purification treatment, thereby improving the adaptability of the flue gas multi-pollutant ultra-clean emission treatment system 100 to low-temperature and high-humidity flue gas conditions.

[0030] Compared to existing technologies that only install purification equipment directly after the desulfurization unit, the flue gas multi-pollutant ultra-clean emission treatment system 100 of this application adds a primary heat exchanger 41, a secondary heat exchanger 42, and a demister 2 between the desulfurization unit 1 and the purification tower 3. The flue gas does not directly enter the purification tower 3 in a high-humidity state; instead, it first passes through the primary heat exchanger 41, the secondary heat exchanger 42, and the demister 2 to reduce humidity before entering the purification tower 3 for purification. According to the embodiments of the present invention, the flue gas multi-pollutant ultra-clean emission treatment system 100 can perform staged heat exchange, demisting, and reheating treatment on the flue gas under conditions of low temperature and high moisture content after desulfurization. This results in the flue gas entering the purification tower 3 having a more suitable temperature and humidity state, thereby providing conditions for the stable operation of the carbon-based catalyst in the purification tower 3 and facilitating the further purification of multiple pollutants in the flue gas.

[0031] According to an embodiment of the present invention, the flue gas multi-pollutant ultra-clean emission treatment system 100 includes a purification tower 3 equipped with a carbon-based catalyst. The primary heat exchanger 41 includes a first heat exchange flow path and a second heat exchange flow path that exchange heat with each other. The inlet of the first heat exchange flow path is connected to the outlet of the desulfurization device 1, the outlet of the first heat exchange flow path is connected to the inlet of the secondary heat exchanger 42, the outlet of the secondary heat exchanger 42 is connected to the inlet of the demister 2, the inlet of the second heat exchange flow path is connected to the outlet of the demister 2, and the outlet of the second heat exchange flow path is connected to the inlet of the purification tower 3. By passing the desulfurized high-humidity flue gas sequentially through the primary heat exchanger 41, the secondary heat exchanger 42, and the demister 2 to reduce humidity, and then returning to the primary heat exchanger 41 for reheating before being sent to the purification tower 3, the flue gas entering the purification tower 3 has a lower moisture content and a more suitable temperature, reducing the adverse effects of high-humidity flue gas on the purification process of the carbon-based catalyst, and facilitating the deep ultra-clean treatment of multiple pollutants.

[0032] In some embodiments of the present invention, such as Figures 1-3 As shown, the primary heat exchanger 41 and the secondary heat exchanger 42 are integrated into a cooling tower 40; or, the primary heat exchanger 41 and the secondary heat exchanger 42 are separate components.

[0033] It is understandable that, such as Figure 3As shown, the primary heat exchanger 41 and the secondary heat exchanger 42 can be integrated into a cooling tower 40. In this case, the primary heat exchanger 41 and the secondary heat exchanger 42 are uniformly installed within the cooling tower 40. The flue gas discharged from the desulfurization unit 1 enters the cooling tower 40, undergoes heat exchange in the primary heat exchanger 41, and then further undergoes heat exchange in the secondary heat exchanger 42. It then enters the demister 2, and the flue gas treated by the demister 2 returns to the second heat exchange path of the primary heat exchanger 41, and after completing its reheating process, enters the purification tower 3. By centrally arranging the primary heat exchanger 41 and the secondary heat exchanger 42 within the same device, the connection paths between devices can be shortened, the system footprint reduced, and the risks of heat dissipation and leakage from intermediate connection points decreased.

[0034] Or, such as Figure 1 and Figure 2 As shown, the primary heat exchanger 41 and the secondary heat exchanger 42 are separate components. In this case, the primary heat exchanger 41 and the secondary heat exchanger 42 are set as independent equipment. The primary heat exchanger 41 is located between the desulfurization unit 1 and the secondary heat exchanger 42, and the secondary heat exchanger 42 is located between the primary heat exchanger 41 and the demister 2. This allows the primary heat exchanger 41 and the secondary heat exchanger 42 to be arranged separately according to the site space conditions, which is more convenient to adapt to the existing flue conditions and modification needs of different units, and also facilitates subsequent maintenance, disassembly and replacement.

[0035] In some embodiments of the present invention, such as Figures 1-3 As shown, the flue gas multi-pollutant ultra-clean emission treatment system 100 also includes an ammonia injection device 5. The ammonia injection device 5 is connected in series between the outlet of the second heat exchange flow path and the inlet of the purification tower 3, and is used to supply ammonia to the flue gas.

[0036] Understandably, the flue gas, after being treated by the primary heat exchanger 41, the secondary heat exchanger 42, and the demister 2, flows out through the second heat exchange path of the primary heat exchanger 41 and enters the ammonia injection device 5. The ammonia injection device 5 can supply ammonia to this portion of the flue gas, pre-mixing it with the ammonia before it enters the purification tower 3. This allows the flue gas to participate in the subsequent purification process together with the ammonia in the presence of the carbon-based catalyst after entering the purification tower 3. Thus, the ammonia injection device 5 provides suitable conditions for the carbon-based catalyst in the purification tower 3, thereby improving the purification effect of pollutants, especially nitrogen oxides, in the flue gas.

[0037] In some embodiments of the present invention, such as Figures 1-3 As shown, the flue gas multi-pollutant ultra-clean emission treatment system 100 also includes a heater 6, which is connected in series between the outlet of the second heat exchange flow path and the inlet of the ammonia injection device 5 for heating the flue gas.

[0038] Understandably, the flue gas flowing out of the second heat exchange path of the primary heat exchanger 41 first enters the heater 6, where it is heated before entering the ammonia injection device 5 to mix with ammonia gas, and then enters the purification tower 3. Thus, when the temperature of the flue gas after the initial heat exchange and demisting treatment is still too low, the heater 6 can supplement the heating of this portion of the flue gas, ensuring that the flue gas entering the ammonia injection device 5 and the purification tower 3 has more suitable temperature conditions.

[0039] In some embodiments, when large fluctuations in flue gas load result in low flue gas temperature exiting the second heat exchange path, or when the subsequent removal efficiency of nitrogen oxides in the flue gas cannot meet the ultra-clean emission requirements, heater 6 can be activated to provide auxiliary heating to the flue gas before it enters the ammonia injection unit 5. Thus, heater 6 not only increases the temperature of the flue gas before it enters the purification tower 3, but also enhances the adaptability of the multi-pollutant ultra-clean emission treatment system 100 to the denitrification process under fluctuating operating conditions.

[0040] In some embodiments of the present invention, such as Figures 1-3 As shown, the purification tower 3 is equipped with a purification tower catalyst outlet, and the flue gas multi-pollutant ultra-clean emission treatment system 100 also includes a boiler 71 and a regeneration tower 8. The flue gas outlet of the boiler 71 is connected to the inlet of the desulfurization unit 1. The regeneration tower 8 is equipped with a catalyst inlet and a regeneration gas outlet. The catalyst inlet is connected to the catalyst outlet of the purification tower. The regeneration tower 8 is used to heat, regenerate, and cool the carbon-based catalyst saturated with adsorption in the purification tower 3. The regeneration gas outlet is connected to the inlet of the desulfurization unit 1 and / or the furnace of the boiler 71.

[0041] Understandably, after purifying the flue gas, the carbon-based catalyst in purification tower 3 will gradually become saturated. At this point, the saturated carbon-based catalyst is discharged from the catalyst outlet of purification tower 3 and enters regeneration tower 8. Regeneration tower 8 heats and regenerates the saturated carbon-based catalyst to desorb the components adsorbed on it. The regenerated catalyst is then cooled to restore its performance. Thus, a recycling path for the carbon-based catalyst is formed between purification tower 3 and regeneration tower 8, reducing the frequency of catalyst replacement and lowering operating costs.

[0042] Simultaneously, the regenerated gas generated during the regeneration process in regeneration tower 8 can be returned to the inlet of desulfurization unit 1 for further treatment of relevant pollutants in the regenerated gas; alternatively, the regenerated gas can also be fed into the furnace of boiler 71 for subsequent treatment in conjunction with the combustion and flue gas treatment pathways on the boiler 71 side. Therefore, regeneration tower 8 not only enables the regeneration and reuse of carbon-based catalysts but also allows the gas generated during the regeneration process to be treated in conjunction with the existing main system, thereby improving the system integration of the entire flue gas multi-pollutant ultra-clean emission treatment system 100.

[0043] In some embodiments, when boiler 71 is a circulating fluidized bed boiler, the regenerated gas discharged from regeneration tower 8 can also be transported to the furnace of boiler 71 through an air supply duct. Specifically, the regenerated gas itself has a high temperature, and its sensible heat can be utilized after entering the furnace. Simultaneously, the regenerated gas may also contain a certain amount of carbon-based catalyst fine powder, which can be used as fuel for combustion after entering the furnace, thereby reducing unit coal consumption. Furthermore, the circulating fluidized bed boiler furnace itself has good in-furnace desulfurization capacity, thus also being able to absorb SO2 in the regenerated gas. Therefore, in the circulating fluidized bed boiler scenario, the regenerated gas discharged from regeneration tower 8 can not only be further processed, but also reduce dependence on independent sulfur resource recovery units, thereby helping to reduce site occupation, engineering costs, and system operation complexity.

[0044] In some embodiments of the present invention, such as Figures 1-3 As shown, the regeneration tower 8 is equipped with a cooling unit, which has an air inlet and an air outlet. The flue gas multi-pollutant ultra-clean emission treatment system 100 also includes a cooling fan 91, which is connected to the air inlet and is used to provide cold air to the cooling unit. The air outlet is connected to the primary air system and / or secondary air system of the boiler 71.

[0045] Understandably, the carbon-based catalyst in regeneration tower 8 is at a high temperature after heating and regeneration. Cooling fan 91 continuously supplies cold air to the cooling unit so that the cold air flows through the cooling unit and exchanges heat with the regenerated carbon-based catalyst, thereby reducing the temperature of the regenerated carbon-based catalyst and facilitating its subsequent transportation and reuse. At the same time, after absorbing heat in the cooling unit, the cold air is discharged from the air outlet and enters the primary air system and / or secondary air system of boiler 71.

[0046] Therefore, while reducing the temperature of the regenerated carbon-based catalyst, the cooling unit can also reuse the heat-exchanged air on the boiler 71 side to achieve heat recovery and improve the stability of the carbon-based catalyst recycling process and the energy utilization efficiency of the flue gas multi-pollutant ultra-clean emission treatment system 100.

[0047] In some embodiments, considering the low temperature of the main flue gas in the purification tower 3, the temperature of the regenerated carbon-based catalyst after cooling by the cooling unit can be controlled below 140°C. The regenerated carbon-based catalyst is more suitable for subsequent transportation and re-participation in the purification process. At the same time, the heat-exchanged air discharged from the cooling unit enters the primary air system and / or secondary air system of the boiler 71. Due to the temperature increase, it can also help stabilize the combustion in the furnace of the boiler 71 and ensure the complete combustion of pulverized coal, thereby achieving waste heat recovery and utilization of the cooling air while completing the cooling of the carbon-based catalyst.

[0048] In some embodiments of the present invention, such as Figures 1-3As shown, the regeneration tower 8 is provided with a regeneration tower catalyst outlet. The flue gas multi-pollutant ultra-clean emission treatment system 100 also includes a vibrating screen 92. The inlet of the vibrating screen 92 is connected to the regeneration tower catalyst outlet, and the outlet of the vibrating screen 92 is connected to the purification tower 3 and the boiler 71 respectively. The vibrating screen 92 is used to screen the regenerated carbon-based catalyst and return the carbon-based catalyst with a particle size greater than or equal to the preset value to the purification tower 3, and transport the carbon-based catalyst with a particle size less than the preset value to the boiler 71.

[0049] Understandably, the regenerated carbon-based catalyst discharged from regeneration tower 8 enters vibrating screen 92, where it is sieved according to particle size. Carbon-based catalysts with particle sizes greater than or equal to a preset value retain better particle morphology and operating conditions, and are therefore returned to purification tower 3 to continue participating in flue gas purification; carbon-based catalysts with particle sizes smaller than the preset value are separated and transported to boiler 71 for further utilization.

[0050] Therefore, the smaller carbon-based catalyst particles generated during the regeneration process will not only not re-enter the purification tower 3 and affect its usage, but can also be recycled as usable carbon-containing materials for the main system, thereby improving the overall utilization rate of the regenerated carbon-based catalyst.

[0051] In some embodiments, the preset value is 2 mm. Carbon-based catalysts with a particle size smaller than the preset value can be pulverized in the pulverizer 93 before being transported to the boiler 71, so that they can be used in the boiler 71 later.

[0052] In some embodiments of the present invention, such as Figures 1-3 As shown, the primary heat exchanger 41 is provided with a first condensate outlet 411 for discharging condensate formed during the flue gas cooling process; and / or, the secondary heat exchanger 42 is provided with a second condensate outlet 421 for discharging condensate formed during the flue gas cooling process.

[0053] Understandably, when the flue gas discharged from desulfurization unit 1 undergoes heat exchange and cooling in the primary heat exchanger 41 and the secondary heat exchanger 42, some moisture in the flue gas will condense and precipitate due to the temperature decrease. Therefore, by providing a first condensate outlet 411 on the primary heat exchanger 41, the condensate formed in the primary heat exchange stage can be discharged in a timely manner; and by providing a second condensate outlet 421 on the secondary heat exchanger 42, the condensate formed in the secondary heat exchange stage can be discharged in a timely manner. Thus, the moisture content of the flue gas can be further reduced before entering the demister 2 and subsequent purification tower 3.

[0054] It should be noted that the first condensate outlet 411 and the second condensate outlet 421 can be set separately or simultaneously.

[0055] In some embodiments of the present invention, such as Figures 1-3As shown, the desulfurization device 1 is a wet desulfurization device, and the first condensate outlet 411 and / or the second condensate outlet 421 are connected to the water supply port of the wet desulfurization device.

[0056] Understandably, the condensate discharged from the first condensate outlet 411 of the primary heat exchanger 41 and the condensate discharged from the second condensate outlet 421 of the secondary heat exchanger 42 can be returned to the water supply inlet of the wet desulfurization unit as a source of water for the wet desulfurization unit 1. Therefore, the condensate generated during the heat exchange process of the primary heat exchanger 41 and the secondary heat exchanger 42 is no longer directly discharged but can be reused in the desulfurization unit 1, thereby improving the water resource utilization rate in the flue gas multi-pollutant ultra-clean emission treatment system 100.

[0057] Specifically, when the first condensate outlet 411 is connected to the water supply inlet of the wet desulfurization unit, the condensate formed in the first heat exchange stage can be recycled and reused; when the second condensate outlet 421 is connected to the water supply inlet of the wet desulfurization unit, the condensate formed in the second heat exchange stage can be recycled and reused; when both are connected to the water supply inlet of the wet desulfurization unit, the condensate formed in both heat exchange stages can be recycled in a unified manner.

[0058] In some embodiments of the present invention, such as Figures 1-3 As shown, the secondary heat exchanger 42 includes a third heat exchange flow path and a fourth heat exchange flow path that exchange heat with each other. The inlet of the third heat exchange flow path is connected to the outlet of the first heat exchange flow path, and the outlet of the third heat exchange flow path is connected to the inlet of the demister 2. The fourth heat exchange flow path is internally circulated with refrigerant, which is used to cool the flue gas in the third heat exchange flow path. The refrigerant is ambient air or cooling water.

[0059] Understandably, the flue gas, after initial heat exchange in the first heat exchange path of the primary heat exchanger 41, enters the third heat exchange path of the secondary heat exchanger 42 through the outlet of the first heat exchange path and continues to flow within the third heat exchange path. The refrigerant in the fourth heat exchange path exchanges heat with the flue gas in the third heat exchange path, further cooling the flue gas in the third heat exchange path. The cooled flue gas then flows out through the outlet of the third heat exchange path and enters the demister 2. Thus, the secondary heat exchanger 42 can further cool the flue gas after its initial treatment by the primary heat exchanger 41, making it easier for moisture in the flue gas to precipitate and providing conditions for the subsequent removal of mist droplets by the demister 2.

[0060] Furthermore, the refrigerant in the fourth heat exchange path can be either ambient air or cooling water. When ambient air is used, it can be used to cool the flue gas in the third heat exchange path; when cooling water is used, its higher heat exchange capacity can be utilized to further reduce the flue gas temperature. With this configuration, the secondary heat exchanger 42 can flexibly select the refrigerant according to different operating conditions and site conditions, ensuring a good deep cooling effect on the flue gas in the third heat exchange path. This helps reduce the moisture content of the flue gas and improves the adaptability of the subsequent demister 2 and purification tower 3 processes.

[0061] The flue gas multi-pollutant ultra-clean emission treatment system 100 according to an embodiment of the present invention can adapt to low-temperature and high-humidity flue gas conditions and meet the needs of existing environmental protection devices for further deep purification of flue gas. Meanwhile, the condensate formed by the primary heat exchanger 41 and the secondary heat exchanger 42 can be reused for process water in the main system, thereby reducing water consumption; the regenerated gas discharged from the regeneration tower 8 can be treated in conjunction with the boiler 71 and the existing desulfurization device 1, thereby reducing dependence on an independent sulfur resource recovery system; in addition, the flue gas multi-pollutant ultra-clean emission treatment system 100 can also utilize the waste heat during the regeneration process of the carbon-based catalyst and the calorific value of the small-diameter carbon-based catalyst particles to achieve energy recovery, thereby helping to reduce the energy consumption of the environmental protection system.

[0062] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0063] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A multi-pollutant ultra-clean emission treatment system for flue gas, characterized in that, include: Desulfurization equipment; Demister; A purification tower, wherein a carbon-based catalyst is provided inside the purification tower; The device includes a primary heat exchanger and a secondary heat exchanger. The primary heat exchanger includes a first heat exchange flow path and a second heat exchange flow path that exchange heat with each other. The inlet of the first heat exchange flow path is connected to the outlet of the desulfurization device. The outlet of the first heat exchange flow path is connected to the inlet of the secondary heat exchanger. The outlet of the secondary heat exchanger is connected to the inlet of the demister. The inlet of the second heat exchange flow path is connected to the outlet of the demister. The outlet of the second heat exchange flow path is connected to the inlet of the purification tower.

2. The flue gas multi-pollutant ultra-clean emission treatment system according to claim 1, characterized in that, The primary heat exchanger and the secondary heat exchanger are integrated into a cooling tower; or, the primary heat exchanger and the secondary heat exchanger are separate components.

3. The flue gas multi-pollutant ultra-clean emission treatment system according to claim 1, characterized in that, Also includes: An ammonia injection device is connected in series between the outlet of the second heat exchange flow path and the inlet of the purification tower, and is used to supply ammonia to the flue gas.

4. The flue gas multi-pollutant ultra-clean emission treatment system according to claim 3, characterized in that, Also includes: A heater is connected in series between the outlet of the second heat exchange path and the inlet of the ammonia injection device for heating the flue gas.

5. The flue gas multi-pollutant ultra-clean emission treatment system according to claim 1, characterized in that, The purification tower is equipped with a purification tower catalyst outlet and also includes: A boiler, wherein the flue gas outlet of the boiler is connected to the inlet of the desulfurization device; The regeneration tower is provided with a catalyst inlet and a regeneration gas outlet. The catalyst inlet is connected to the catalyst outlet of the purification tower. The regeneration tower is used to heat, regenerate, and cool the carbon-based catalyst that is saturated with adsorption in the purification tower. The regeneration gas outlet is connected to the inlet of the desulfurization unit and / or the furnace of the boiler.

6. The flue gas multi-pollutant ultra-clean emission treatment system according to claim 5, characterized in that, The regeneration tower is equipped with a cooling unit, which has an air inlet and an air outlet, and further includes: A cooling fan is connected to the air inlet and is used to provide cold air to the cooling unit. The air outlet is connected to the primary air system and / or secondary air system of the boiler.

7. The flue gas multi-pollutant ultra-clean emission treatment system according to claim 5, characterized in that, The regeneration tower is provided with a regeneration tower catalyst outlet and also includes: The vibrating screen has its inlet connected to the catalyst outlet of the regeneration tower, and its outlet connected to the purification tower and the boiler. The vibrating screen is used to screen the regenerated carbon-based catalyst and return the carbon-based catalyst with a particle size greater than or equal to a preset value to the purification tower, while conveying the carbon-based catalyst with a particle size less than the preset value to the boiler.

8. The flue gas multi-pollutant ultra-clean emission treatment system according to claim 1, characterized in that, The primary heat exchanger is provided with a first condensate outlet for discharging the condensate formed during the flue gas cooling process; And / or, the secondary heat exchanger is provided with a second condensate outlet for discharging condensate formed during the flue gas cooling process.

9. The flue gas multi-pollutant ultra-clean emission treatment system according to claim 8, characterized in that, The desulfurization device is a wet desulfurization device, and the first condensate outlet and / or the second condensate outlet are connected to the water inlet of the wet desulfurization device.

10. The flue gas multi-pollutant ultra-clean emission treatment system according to claim 1, characterized in that, The secondary heat exchanger includes a third heat exchange path and a fourth heat exchange path that exchange heat with each other. The inlet of the third heat exchange path is connected to the outlet of the first heat exchange path, and the outlet of the third heat exchange path is connected to the inlet of the demister. The fourth heat exchange path is internally circulated with refrigerant, which is used to cool the flue gas in the third heat exchange path. The refrigerant is ambient air or cooling water.

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