Flue gas recycling system

Abstract

The invention provides a flue gas recycling system. The flue gas recycling system comprises a regenerator, a dryer and flue gas purification equipment, the regenerator is connected between the combustion equipment and the dryer and connected between a working medium inlet and a working medium outlet of the flue gas purification equipment, and the dryer is connected with the flue gas purification equipment. According to the flue gas recycling system, flue gas generated by the combustion equipment firstly reaches the regenerator to evaporate moisture in a working medium through heat exchange, then reaches the dryer to dry fuel and then reaches the flue gas purification equipment to remove pollutants and moisture, so that the flue gas is purified, and waste heat of the flue gas is recycled in a multi-gradient manner. Moisture removed from the flue gas is mixed with the working medium and then reaches the regenerator, and the moisture is evaporated through heat exchange with the flue gas, so that the moisture in the flue gas is fully recycled. And the flue gas recycling system provided by the embodiment of the invention has relatively low energy consumption.

Description

Technical Field

[0001] This invention relates to the field of flue gas recovery, and more specifically to a flue gas recovery and utilization system. Background Technology

[0002] Combustion equipment such as boilers and incinerators emit flue gas containing pollutants, water vapor, and waste heat during operation. Related technologies incorporate absorption towers to remove pollutants from the flue gas and perform multi-gradient recovery of waste heat. However, the multi-gradient waste heat recovery structure in these technologies is often flawed, failing to fully recover and utilize the waste heat, and exhibiting high energy consumption. Furthermore, the insufficient recovery of water vapor from the flue gas leads to water waste. Summary of the Invention

[0003] The present invention aims to at least partially solve one of the technical problems in the related art.

[0004] Therefore, embodiments of the present invention propose a flue gas recovery and utilization system.

[0005] The flue gas recovery and utilization system of this invention includes: The system includes a regenerator, a dryer, and a flue gas purification device. The regenerator is connected between the combustion device and the dryer, and between the working fluid inlet and outlet of the flue gas purification device. It is used to exchange heat between the flue gas generated by the combustion device and the working fluid discharged from the working fluid outlet to evaporate the moisture in the working fluid. The dryer is connected to the flue gas purification device and is used to receive the flue gas discharged from the regenerator to dry the fuel and supply the flue gas to the flue gas purification device. The flue gas purification device is used to remove moisture from the flue gas and remove pollutants from the flue gas through the working fluid, and the moisture and working fluid are mixed and discharged from the working fluid outlet.

[0006] The flue gas recovery and utilization system of this invention first sends the flue gas generated by the combustion equipment to a regenerator to evaporate the moisture in the working fluid through heat exchange, then to a dryer to dry the fuel, and finally to a flue gas purification device to remove pollutants and moisture, thereby purifying the flue gas and recovering the waste heat of the flue gas in a multi-gradient manner. The moisture removed from the flue gas is mixed with the working fluid and then sent to the regenerator, where it evaporates through heat exchange with the flue gas, thus fully recovering the moisture in the flue gas. Furthermore, the flue gas recovery and utilization system of this invention has low energy consumption.

[0007] In some embodiments, the flue gas recovery system further includes a regenerator, one heat exchange chamber of which is connected between the working fluid outlet and the regenerator, and another heat exchange chamber of which is connected between the working fluid inlet and the regenerator, for exchanging heat between the working fluid supplied to the working fluid inlet and the working fluid discharged from the working fluid outlet to heat the working fluid discharged from the working fluid outlet.

[0008] In some embodiments, the flue gas recovery and utilization system further includes a condenser, and the flue gas purification equipment includes a cooling device for supplying a cooling medium and exchanging heat between the cooling medium and the flue gas and / or working fluid in the flue gas purification equipment. The condenser is connected to the outlet end of the cooling device and to the steam outlet of the regenerator for exchanging heat between the cooling medium discharged from the cooling device and the steam discharged from the steam outlet to condense the steam.

[0009] In some embodiments, the cooling medium is water, the combustion device includes a boiler, the inlet end of one heat exchange chamber of the condenser is connected to the outlet end of the cooling device, the inlet end of the other heat exchange chamber of the condenser is connected to the steam outlet of the regenerator, and the outlet end of the one heat exchange chamber and / or the outlet end of the other heat exchange chamber of the condenser is connected to the boiler.

[0010] In some embodiments, the flue gas purification device is an absorption tower, and the absorption tower includes the cooling device.

[0011] In some embodiments, the absorption tower further includes a baffle plate with a gas lift cap, a first spray pipe and a second spray pipe, the baffle plate dividing the internal space of the absorption tower into a first space and a second space, the gas lift cap for flue gas to enter the second space from the first space, the first space having a first spray pipe and a first working fluid outlet, the first spray pipe having a first working fluid inlet for spraying the first working fluid, the second space having a second spray pipe and a second working fluid outlet, the second spray pipe having a second working fluid inlet for spraying the second working fluid, and both the second working fluid inlet and the second working fluid outlet being connected to the regenerator.

[0012] In some embodiments, the absorption tower further includes a circulation pipeline, a pH detection device, and a first working fluid replenishment device. The circulation pipeline is connected between the first working fluid outlet and the first working fluid inlet. The pH detection device is located at the first working fluid outlet or the circulation pipeline and is used to detect the pH value of the first working fluid discharged from the first working fluid outlet. The first working fluid replenishment device is located in the circulation pipeline and is used to replenish the first working fluid into the circulation pipeline when the pH value detected by the pH detection device is less than a preset pH value.

[0013] In some embodiments, the cooling device includes a first falling film tube and a second falling film tube, the first falling film tube being disposed in the first space, the second falling film tube being disposed in the second space, the outlet end of the second falling film tube being connected to the inlet end of the first falling film tube, so that the cooling medium flows sequentially through the second falling film tube and the first falling film tube, and the outlet end of the first falling film tube being connected to the condenser.

[0014] In some embodiments, the first falling film pipe is located between the flue gas inlet of the absorption tower and the first spray pipe, with the inlet end of the first falling film pipe being closer to the first spray pipe than the outlet end of the first falling film pipe; the second falling film pipe is located between the rising cap and the second spray pipe, with the inlet end of the second falling film pipe being closer to the rising cap than the outlet end of the second falling film pipe.

[0015] In some embodiments, the first working medium is water or an alkaline solution, and the second working medium is a hygroscopic solution.

[0016] In some embodiments, the dryer is used to contact flue gas with fuel to dry the fuel. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a flue gas recovery and utilization system according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the flue gas purification equipment in the flue gas recovery and utilization system of this invention.

[0018] Figure label: 1. Regenerator; 2. Dryer; 3. Flue gas purification equipment; 31. Cooling device; 311. First falling film tube; 312. Second falling film tube; 32. Gas lifting cap; 33. Baffle; 34. First spray tube; 341. First working fluid inlet; 35. Second spray tube; 351. Second working fluid inlet; 36. First space; 37. Second space; 38. First working fluid outlet; 39. Second working fluid outlet; 310. Flue gas inlet; 320. Flue gas outlet; 330. Demister; 4. Combustion equipment; 5. Regenerator; 6. Condenser. Detailed Implementation

[0019] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0020] The following is for reference. Figure 1 and Figure 2 A flue gas recovery and utilization system according to an embodiment of the present invention is described.

[0021] like Figure 1 and Figure 2 As shown, the flue gas recovery and utilization system of this invention includes a regenerator 1, a dryer 2, and a flue gas purification device 3.

[0022] Regenerator 1 is connected between combustion device 4 and dryer 2, and between the working fluid inlet and outlet of flue gas purification device 3. It is used to exchange heat between the flue gas generated by combustion device 4 and the working fluid discharged from the outlet to evaporate moisture in the working fluid. Figure 1 As shown, the hot side chamber of regenerator 1 is connected between combustion device 4 and dryer 2, and the cold side chamber of regenerator 1 is connected between working fluid outlet and working fluid inlet.

[0023] Dryer 2 is connected to flue gas purification equipment 3, used to receive the flue gas discharged from regenerator 1 to dry the fuel, and to supply the flue gas to flue gas purification equipment 3. For example... Figure 1 and Figure 2 As shown, the dryer 2 is connected between the hot side cavity of the regenerator 1 and the flue gas inlet 310 of the flue gas purification device 3.

[0024] The flue gas purification device 3 is used to remove moisture from the flue gas and remove pollutants from the flue gas through the working fluid, and the moisture and working fluid are mixed and discharged from the working fluid outlet.

[0025] During the operation of the flue gas recovery and utilization system, the flue gas generated by the combustion device 4 can be selected to enter the hot side cavity of the regenerator 1 at a high grade of 200℃~300℃. After heat exchange to heat the working medium, it can be selected to be cooled to a medium grade of 120℃~150℃. Then it enters the dryer 2 to dry the fuel, and is further cooled to a low grade of 90℃ and below. Then it enters the flue gas purification device 3 to be purified, thereby recovering the waste heat of the flue gas in multiple gradients.

[0026] Moisture in the flue gas is fully removed in the flue gas purification device 3 to avoid water waste caused by the flue gas. After the moisture is mixed with the working fluid, it is discharged from the working fluid outlet to the cold side chamber of the regenerator 1. The residual heat of the flue gas is used to evaporate the moisture to achieve moisture recovery and make full use of the residual heat of the flue gas. At the same time, evaporating the moisture can increase the concentration of the working fluid, so that the working fluid returns to the flue gas purification device 3 through the working fluid inlet. It has a high purification, residual heat and residual moisture recovery effect on the flue gas, realizing the recycling of the working fluid.

[0027] Dryer 2 uses the waste heat of flue gas to dry the fuel, making full use of the waste heat of flue gas on the one hand, and improving the combustion efficiency of the fuel on the other.

[0028] In the flue gas recovery and utilization system of this invention, the flue gas generated by the combustion device 4 first reaches the regenerator 1 to evaporate the moisture in the working fluid through heat exchange, then reaches the dryer 2 to dry the fuel, and finally reaches the flue gas purification device 3 to remove pollutants and moisture, thereby purifying the flue gas and recovering the waste heat of the flue gas in a multi-gradient manner. The moisture removed from the flue gas is mixed with the working fluid and then reaches the regenerator 1, where it evaporates through heat exchange with the flue gas, thereby fully recovering the moisture in the flue gas. Furthermore, the flue gas recovery and utilization system of this invention has low energy consumption.

[0029] Optionally, the flue gas recovery and utilization system of this embodiment of the invention can treat the flue gas into dry flue gas with an unsaturation of up to 10°C.

[0030] In some embodiments, such as Figure 1 As shown, dryer 2 is used to dry fuel by contacting it with flue gas. Specifically, dryer 2 has a flue gas inlet and a flue gas outlet that connect to the inner cavity. The flue gas inlet is connected to the hot side cavity of regenerator 1 so that the flue gas discharged from regenerator 1 enters the inner cavity of dryer 2 and directly contacts the fuel in the inner cavity of dryer 2 to dry the fuel. The flue gas outlet is connected to the flue gas inlet 310 of flue gas purification equipment 3. Water vapor discharged during the fuel drying process mixes with the flue gas and is then supplied to flue gas purification equipment 3 through the flue gas outlet. Water vapor from the fuel and water vapor originally in the flue gas are fully removed in flue gas purification equipment 3 and evaporated in the cold side cavity of regenerator 1 for recovery, thereby avoiding the waste of moisture in fuel and flue gas.

[0031] Fuels can be selected from biomass fuel, coal, solid waste fuel, etc.

[0032] In some embodiments, such as Figure 1 As shown, the flue gas recovery and utilization system also includes a regenerator 5. The regenerator 5 serves as one heat exchange chamber on the cold side, connected between the working fluid outlet and the regenerator 1. The regenerator 5 also serves as another heat exchange chamber on the hot side, connected between the working fluid inlet and the regenerator 1. It is used to exchange heat between the working fluid supplied to the working fluid inlet and the working fluid discharged from the working fluid outlet to heat the working fluid discharged from the working fluid outlet. Specifically, the working fluid discharged from the flue gas purification device 3 passes through the cold side chamber of the regenerator 5, the cold side chamber of the regenerator 1, and the hot side chamber of the regenerator 5 in sequence before returning to the flue gas purification device 3. The working fluid absorbs heat from the flue gas and evaporates moisture in the cold side chamber of the regenerator 1. Then, the heat carried in the regenerator 5 is exchanged with the working fluid flowing to the regenerator 1 for preheating, thereby increasing the temperature of the working fluid in the cold side chamber of the regenerator 1 and evaporating as much moisture as possible in the working fluid.

[0033] In some embodiments, such as Figure 1 As shown, the flue gas recovery and utilization system also includes a condenser 6, and the flue gas purification equipment 3 includes a cooling device 31. The cooling device 31 is used to supply the flow of the cooling medium and to exchange heat between the cooling medium and the flue gas and / or working fluid in the flue gas purification equipment 3. It can be selected to cool the flue gas and working fluid in the flue gas purification equipment 3. On the one hand, the temperature of the working fluid increases after absorbing heat and moisture from the flue gas, and the absorption efficiency decreases. Cooling the working fluid can significantly increase the absorption efficiency. On the other hand, it can condense some of the water vapor in the flue gas to remove it from the flue gas. It can be understood that the flue gas temperature can also be lowered by passing through the regenerator 1 and the dryer 2 before reaching the flue gas purification equipment 3, and is in the optimal operating temperature range for the working fluid to absorb moisture from the flue gas.

[0034] The condenser 6 is connected to the outlet end of the cooling device 31 and to the steam outlet of the regenerator 1. It is used for heat exchange between the cooling medium discharged from the cooling device 31 and the steam discharged from the steam outlet to condense the steam. Specifically, the regenerator 1 is provided with a steam outlet communicating with its cold side chamber. The water vapor generated by the working medium absorbing heat in the cold side chamber of the regenerator 1 is discharged through the steam outlet. The steam outlet is connected to the hot side chamber of the condenser 6. The cold side chamber of the condenser 6 is connected to the outlet end of the cooling device 31. The steam discharged from the steam outlet exchanges heat with the cooling medium discharged from the cooling device 31 in the condenser 6 to cool the steam and condense it, thereby facilitating the recovery of water.

[0035] In some embodiments, such as Figure 1 As shown, the cooling medium is water. The combustion device 4 includes a boiler. The inlet end of the condenser 6, which serves as a heat exchange chamber on the cold side, is connected to the outlet end of the cooling device 31. The inlet end of the condenser 6, which serves as another heat exchange chamber on the hot side, is connected to the steam outlet of the regenerator 1. The steam discharged from the steam outlet exchanges heat with the water, which serves as the cooling medium, discharged from the cooling device 31 in the condenser 6, so as to cool the steam and form condensate. The outlet end of the condenser 6, which serves as a heat exchange chamber on the cold side, and / or the outlet end of the condenser 6, which serves as the other heat exchange chamber on the hot side, is connected to the boiler. The water, which serves as the cooling medium, discharged from the cold side of the condenser 6 and the condensate discharged from the hot side of the condenser 6 can be supplied to the boiler for use. Alternatively, the water, which serves as the cooling medium, discharged from the cold side of the condenser 6 can be supplied to the boiler for use, and the condensate discharged from the hot side of the condenser 6 can be supplied to a recovery container for further treatment.

[0036] It is understandable that, such as Figure 1 As shown, the fuel dried by dryer 2 can be supplied to the boiler for combustion and heating.

[0037] In some embodiments, such as Figure 1 and Figure 2 As shown, the flue gas purification device 3 is an absorption tower. Flue gas enters the absorption tower and is desulfurized and / or denitrified by the working fluid. The absorption tower includes a cooling device 31 to condense water vapor in the flue gas.

[0038] In some embodiments, such as Figure 2 As shown, the absorption tower also includes a baffle 33 with a gas lifting cap 32, a first spray pipe 34, and a second spray pipe 35.

[0039] The baffle 33 divides the internal space of the absorption tower into a first space 36 and a second space 37, and the riser 32 is used for flue gas to enter the second space 37 from the first space 36. Figure 2As shown, the first space 36 can be located below the second space 37. The bottom of the absorption tower is provided with a flue gas inlet 310 communicating with the first space 36, and the top of the absorption tower is provided with a flue gas outlet 320 communicating with the second space 37. The flue gas inlet 310 is connected to the exhaust port of the dryer 2. The flue gas supplied to the absorption tower by the dryer 2 first enters the first space 36 for the first purification treatment, then enters the second space 37 through the riser cap 32 for the second purification treatment, and then is discharged through the flue gas outlet 320.

[0040] The first space 36 is provided with a first spray pipe 34 and a first working medium outlet 38. The first spray pipe 34 is provided with a first working medium inlet 341 for spraying the first working medium. Figure 2 As shown, the first spray pipe 34 can be located at the top of the first space 36, and the first working medium outlet 38 can be located at the bottom of the first space 36. During the upward flow of flue gas in the first space 36, it comes into contact with the first working medium sprayed downward by the first spray pipe 34. The first working medium can be water or an alkaline solution to absorb sulfur dioxide, particulate matter and heat in the flue gas in the first space 36.

[0041] The second space 37 is provided with a second spray pipe 35 and a second working fluid outlet 39. The second spray pipe 35 is provided with a second working fluid inlet 351 for spraying the second working fluid. Figure 2 As shown, the second spray pipe 35 can be located at the top of the second space 37, and the second working fluid outlet 39 can be located at the bottom of the second space 37. During the upward flow of flue gas in the second space 37, the second spray pipe 35 comes into contact with the downward spraying second working fluid. The second working fluid can be a hygroscopic solution, such as a halogen solution, formate, acetate solution, etc., to absorb moisture and heat in the flue gas in the second space 37.

[0042] The second working fluid inlet 351 and the second working fluid outlet 39 are both connected to the regenerator 1, such as Figure 1 and Figure 2 As shown, the second working fluid outlet 39, the cold side chamber of the regenerator 5, the cold side chamber of the regenerator 1, the hot side chamber of the regenerator 5, and the second working fluid inlet 351 are connected in sequence. The second working fluid absorbs moisture from the flue gas in the second space 37 and becomes a dilute solution. After being preheated in the cold side chamber of the regenerator 5, it reaches the cold side chamber of the regenerator 1 and absorbs heat from the flue gas to evaporate the moisture, thus becoming a high-temperature concentrated solution. After releasing heat in the hot side chamber of the regenerator 5, it is supplied to the second spray pipe 35 for spraying again. The absorption efficiency of the cooled concentrated solution increases, thereby utilizing the waste heat of the flue gas to enable the second working fluid to be used efficiently and to extract and recover moisture from the flue gas.

[0043] Optionally, the partition 33 is inclined, and the second working medium outlet 39 is located at the bottom of the partition 33, so as to facilitate the discharge of the second working medium in the second space 37 and avoid the accumulation of the second working medium.

[0044] In some embodiments, the absorption tower further includes a circulation pipeline, a pH detection device, and a first working fluid replenishment device. The circulation pipeline is connected between the first working fluid outlet 38 and the first working fluid inlet 341. The pH detection device is located at the first working fluid outlet 38 or the circulation pipeline and is used to detect the pH value of the first working fluid discharged from the first working fluid outlet 38. The first working fluid replenishment device is located in the circulation pipeline and is used to replenish the first working fluid into the circulation pipeline when the pH value detected by the pH detection device is less than a preset pH value. The preset pH value can be selected as 5. When the pH value of the first working fluid discharged from the first working fluid outlet 38 is greater than or equal to 5, the first working fluid is supplied to the first spray pipe 34 through the circulation pipeline for reuse. When the pH value of the first working fluid discharged from the first working fluid outlet 38 is less than 5, the first working fluid replenishment device replenishes the first working fluid into the circulation pipeline so that the pH value of the first working fluid in the circulation pipeline reaches greater than or equal to 5, and then it is supplied to the first spray pipe 34 through the circulation pipeline for reuse.

[0045] In some embodiments, such as Figure 2 As shown, the cooling device 31 includes a first falling film tube 311 and a second falling film tube 312.

[0046] The first falling film tube 311 is located in the first space 36. The first working fluid sprayed by the first spray tube 34 flows down along the first falling film tube 311 to fully absorb sulfur dioxide, particulate matter and heat in the flue gas, and transfer the heat to the cooling medium in the first falling film tube 311. At the same time, the first falling film tube 311 is in the flue gas and also plays a role in heat exchange and cooling of the flue gas.

[0047] The second falling film tube 312 is located in the second space 37. The second working fluid sprayed by the second spray tube 35 flows down along the second falling film tube 312 to fully absorb the moisture and heat in the flue gas and transfer the heat to the cooling medium inside the second falling film tube 312. Cooling the working fluid can ensure efficient absorption. At the same time, the second falling film tube 312 is in the flue gas and also plays a role in heat exchange and cooling of the flue gas.

[0048] The outlet end of the second falling film tube 312 is connected to the inlet end of the first falling film tube 311, so that the cooling medium flows through the second falling film tube 312 and the first falling film tube 311 in sequence. Therefore, the temperature of the cooling medium in the second falling film tube 312 is lower than that in the first falling film tube 311, thereby improving the efficiency of the cooling medium in absorbing heat in the second falling film tube 312 and the first falling film tube 311. At the same time, the cooling medium is kept below 50°C in the second falling film tube 312 to create a temperature environment suitable for the first working fluid to absorb moisture, thereby improving the moisture removal effect. The cooling medium is kept between 70°C and 80°C in the first falling film tube 311 to create a temperature environment suitable for the wet absorption of sulfur dioxide, thereby improving the sulfur dioxide removal effect. Furthermore, the temperature of the cooling medium in the first falling film tube 311 is higher than the dew point temperature of the flue gas, so that the moisture in the flue gas does not condense in the first space 36, but is fully absorbed by the second working fluid in the second space 37, thereby facilitating its recovery in cooperation with the regenerator 1 and the condenser 6.

[0049] The outlet end of the first falling film tube 311 is connected to the condenser 6. The cooling medium is discharged from the outlet end of the first falling film tube 311 to the cold side cavity of the condenser 6 to exchange heat with water vapor in the condenser 6 for condensation.

[0050] In some embodiments, such as Figure 2 As shown, the first falling film pipe 311 is located between the flue gas inlet 310 and the first spray pipe 34 of the absorption tower, so that the first working medium sprayed by the first spray pipe 34 can fall on the first falling film pipe 311 and make full contact with the flue gas. The inlet end of the first falling film pipe 311 is closer to the first spray pipe 34 than the outlet end of the first falling film pipe 311. In other words, the inlet of the first falling film pipe 311 is higher than the outlet. The cooling medium flows from top to bottom in the first falling film pipe 311 and is opposite to the flow direction of the flue gas in the first space 36, so as to fully absorb the heat of the first working medium and the flue gas.

[0051] The second falling film tube 312 is located between the gas lifting cap 32 and the second spray tube 35, so that the second working medium sprayed by the second spray tube 35 can fall onto the second falling film tube 312 and make full contact with the flue gas. The inlet end of the second falling film tube 312 is closer to the gas lifting cap 32 than the outlet end of the second falling film tube 312. In other words, the inlet of the second falling film tube 312 is higher than the outlet. The cooling medium flows from bottom to top in the second falling film tube 312 and is in the same direction as the flue gas flow in the second space 37, so as to fully absorb the heat of the second working medium and the flue gas.

[0052] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and 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. Therefore, they should not be construed as limitations on this invention.

[0053] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0054] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0055] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0056] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0057] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A flue gas recovery and utilization system, characterized in that, include: The regenerator (1), dryer (2), and flue gas purification device (3) are connected between the combustion device (4) and the dryer (2), and between the working fluid inlet and the working fluid outlet of the flue gas purification device (3). The regenerator (1) is used to exchange heat between the flue gas generated by the combustion device (4) and the working fluid discharged from the working fluid outlet to evaporate the moisture in the working fluid. The dryer (2) is connected to the flue gas purification device (3) and is used to receive the flue gas discharged from the regenerator (1) to dry the fuel and supply the flue gas to the flue gas purification device (3). The flue gas purification device (3) is used to remove the moisture in the flue gas and remove pollutants in the flue gas through the working fluid, and discharge the moisture and working fluid through the working fluid outlet.

2. The flue gas recovery and utilization system according to claim 1, characterized in that, It also includes a regenerator (5), one heat exchange chamber of which is connected between the working fluid outlet and the regenerator (1), and the other heat exchange chamber of which is connected between the working fluid inlet and the regenerator (1), for exchanging heat between the working fluid supplied to the working fluid inlet and the working fluid discharged from the working fluid outlet to heat the working fluid discharged from the working fluid outlet.

3. The flue gas recovery and utilization system according to claim 1, characterized in that, It also includes a condenser (6), and the flue gas purification equipment (3) includes a cooling device (31), which is used to supply cooling medium flow and to exchange heat between the cooling medium and the flue gas and / or working fluid in the flue gas purification equipment (3). The condenser (6) is connected to the outlet end of the cooling device (31) and to the steam outlet of the regenerator (1) for the cooling medium discharged from the cooling device (31) to exchange heat with the steam discharged from the steam outlet so that the steam condenses.

4. The flue gas recovery and utilization system according to claim 3, characterized in that, The cooling medium is water, the combustion device (4) includes a boiler, the inlet end of one heat exchange chamber of the condenser (6) is connected to the outlet end of the cooling device (31), the inlet end of the other heat exchange chamber of the condenser (6) is connected to the steam outlet of the regenerator (1), and the outlet end of one heat exchange chamber of the condenser (6) and / or the outlet end of the other heat exchange chamber of the condenser (6) is connected to the boiler.

5. The flue gas recovery and utilization system according to claim 3, characterized in that, The flue gas purification equipment (3) is an absorption tower, and the absorption tower includes the cooling device (31).

6. The flue gas recovery and utilization system according to claim 5, characterized in that, The absorption tower also includes a partition (33) with a gas lift cap (32), a first spray pipe (34) and a second spray pipe (35). The partition (33) divides the internal space of the absorption tower into a first space (36) and a second space (37). The gas lift cap (32) is used for flue gas to enter the second space (37) from the first space (36). The first space (36) is provided with a first spray pipe (34) and a first working medium outlet (38). The first spray pipe (34) is provided with a first working medium inlet (341) to spray the first working medium. The second space (37) is provided with a second spray pipe (35) and a second working medium outlet (39). The second spray pipe (35) is provided with a second working medium inlet (351) to spray the second working medium. The second working medium inlet (351) and the second working medium outlet (39) are both connected to the regenerator (1).

7. The flue gas recovery and utilization system according to claim 6, characterized in that, The absorption tower also includes a circulation pipeline, a pH detection device, and a first working fluid replenishment device. The circulation pipeline is connected between the first working fluid outlet (38) and the first working fluid inlet (341). The pH detection device is located at the first working fluid outlet (38) or the circulation pipeline and is used to detect the pH value of the first working fluid discharged from the first working fluid outlet (38). The first working fluid replenishment device is located in the circulation pipeline and is used to replenish the first working fluid into the circulation pipeline when the pH value detected by the pH detection device is less than a preset pH value.

8. The flue gas recovery and utilization system according to claim 6, characterized in that, The cooling device (31) includes a first falling film tube (311) and a second falling film tube (312). The first falling film tube (311) is located in the first space (36), and the second falling film tube (312) is located in the second space (37). The outlet end of the second falling film tube (312) is connected to the inlet end of the first falling film tube (311) so that the cooling medium flows through the second falling film tube (312) and the first falling film tube (311) in sequence. The outlet end of the first falling film tube (311) is connected to the condenser (6).

9. The flue gas recovery and utilization system according to claim 8, characterized in that, The first falling film pipe (311) is located between the flue gas inlet (310) of the absorption tower and the first spray pipe (34). The inlet end of the first falling film pipe (311) is closer to the first spray pipe (34) than the outlet end of the first falling film pipe (311). The second falling film pipe (312) is located between the gas lifting cap (32) and the second spray pipe (35). The inlet end of the second falling film pipe (312) is closer to the gas lifting cap (32) than the outlet end of the second falling film pipe (312).

10. The flue gas recovery and utilization system according to claim 6, characterized in that, The first working medium is water or an alkaline solution, and the second working medium is a hygroscopic solution; and / or The dryer (2) is used to dry the fuel by contacting the flue gas with it.

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