A flue gas water extraction and dewhitening device

Abstract

The present invention discloses a flue gas water-intake and dewhitening device, comprising a first-stage sensible heat exchanger, a second-stage latent heat exchanger and a pipeline; the first-stage sensible heat exchanger and the second-stage latent heat exchanger are arranged in series in a vertical manner; the first-stage sensible heat exchanger is used to reduce the temperature of the original flue gas to the water dew point temperature; the second-stage latent heat exchanger is also provided with a cooling water outlet and a cooling water inlet, which are used to reduce the flue gas passing through the first-stage latent heat exchanger to a temperature below the water dew point; and a recess is provided on the pipeline. Since the original flue gas is reduced to about the water dew point in the first-stage sensible heat exchanger, the water vapor in the original flue gas does not condense or condenses a small amount, thereby minimizing the risk of dust accumulation, blockage, scaling, corrosion and other problems in the first-stage sensible heat exchanger. In addition, the present invention adopts a vertical combination of recovering flue gas waste heat and water cooling, which saves floor space, avoids high energy consumption and high investment caused by air cooling, reduces energy consumption, and reduces the probability of dust blockage.

Description

Technical Field

[0001] The invention relates to the technical field of flue gas treatment equipment, and in particular to a flue gas water intake and dewhitening device. Background Art

[0002] In order to eliminate the "white smoke" pollution in industrial flue gas emissions, it is necessary to add a flue gas dewhitening device. At present, the commonly used flue gas dewhitening device generally needs to set up a series of processing modules such as condensation and reheating. For many renovation projects, due to the limited site, it is impossible to provide enough equipment layout space. Therefore, it is very important to minimize the floor space of the flue gas dewhitening device. The existing flue gas dewhitening device mainly adopts the form of coupling with wet flue gas desulfurization, or by cooling the wet flue gas desulfurization spray slurry, or by improving the wet flue gas desulfurization tower, adding a heat exchange dehumidification and reheating module in the tower or on the top of the tower to achieve the function of flue gas dewhitening in the wet flue gas desulfurization tower at the same time. This form cannot be applied to industrial flue gas dewhitening using other flue gas purification processes. Other flue gas dewhitening devices that use air-to-air heat exchangers use air as the heat exchange medium to cool the flue gas to below the water dew point, with a huge heat exchange capacity; plate heat exchangers require a large amount of air for heat exchange, and the blower consumes a lot of energy; when the flue gas condenses, the smoke particles carried in the flue gas are also washed off at the same time, which can easily cause dust accumulation and blockage on the heat exchange surface, and the plate heat exchanger has a small gap, making it difficult to clean.

[0003] Therefore, how to reduce the energy consumption of the flue gas water extraction and dewhitening device, reduce the probability of dust blockage, and save floor space is a technical problem that needs to be urgently solved by technical personnel in this field. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide a flue gas water intake and dewhitening device, which can reduce energy consumption, reduce the probability of dust blockage, and save floor space.

[0005] In order to achieve the above object, the present invention provides the following scheme:

[0006] A flue gas water intake and dewhitening device comprises a first-stage sensible heat exchanger, a second-stage latent heat exchanger and a pipeline;

[0007] The first-stage sensible heat exchanger and the second-stage latent heat exchanger are both arranged vertically, and the first flue gas inlet of the first-stage sensible heat exchanger is used to input raw flue gas, the first flue gas outlet of the first-stage sensible heat exchanger is conductively connected to the flue gas inlet of the second-stage latent heat exchanger, the flue gas outlet of the second-stage latent heat exchanger is conductively connected to the second flue gas inlet of the first-stage sensible heat exchanger through a pipeline, and the second flue gas outlet of the first-stage sensible heat exchanger is used to discharge the treated flue gas;

[0008] The first stage sensible heat exchanger is used to reduce the temperature of the raw flue gas to the water dew point temperature;

[0009] The second-stage latent heat exchanger is also provided with a cooling water outlet and a cooling water inlet for introducing cooling water to reduce the temperature of the flue gas passing through the first-stage latent heat exchanger to a temperature below the water dew point;

[0010] The pipeline is provided with a recessed portion capable of containing condensed liquid condensed by the second-stage latent heat exchanger.

[0011] In a specific embodiment, the second-stage latent heat exchanger is composed of preset modules that can be detachably assembled.

[0012] In another specific embodiment, the second-stage latent heat exchanger is formed by assembling the modules along the longitudinal direction.

[0013] In another specific embodiment, the pipeline includes a first vertical pipe, a second vertical pipe, an inclined pipe, and a horizontal pipe;

[0014] The inlet of the first vertical tube is conductively connected to the flue gas outlet of the second-stage latent heat exchanger, the outlet of the first vertical tube is conductively connected to the inlet of the inclined tube, the outlet of the inclined tube is conductively connected to the inlet of the second vertical tube, and the outlet of the second vertical tube is conductively connected to the second flue gas inlet of the first-stage sensible heat exchanger;

[0015] The inclined tube is inclined at a preset angle to a horizontal plane, and the recess is formed by the intersection of the inclined tube and the first vertical tube.

[0016] In another specific embodiment, the flue gas water intake and dewhitening device further comprises a demister;

[0017] The demister is installed in the second vertical pipe.

[0018] In another specific embodiment, the flue gas water intake and dewhitening device further comprises a drain pipe;

[0019] The inlet of the drain pipe is conductively connected to the bottom end of the recess.

[0020] In another specific embodiment, a switch valve is provided on the drain pipe.

[0021] In another specific embodiment, the second-stage latent heat exchanger is a metal fin radiator, a fluoroplastic steel heat exchanger or a fluoroplastic heat exchanger.

[0022] In another specific embodiment, the fins of the metal fin heat sink are made of stainless steel, aluminum alloy or ND steel.

[0023] In another specific embodiment, the demister is a wire mesh demister, a baffle demister, a ridge demister or a tube bundle demister;

[0024] and / or

[0025] The preset angle is greater than or equal to 5° and less than or equal to 10°;

[0026] and / or

[0027] The first-stage sensible heat exchanger is a plate heat exchanger;

[0028] and / or

[0029] The heat exchange tube bundle of the second-stage latent heat exchanger is arranged perpendicular to the flue gas flow direction in the second-stage latent heat exchanger.

[0030] The various embodiments according to the present invention can be arbitrarily combined as needed, and the embodiments obtained after these combinations are also within the scope of the present invention and are part of the specific implementation methods of the present invention.

[0031] Without being limited to any theory, it can be seen from the above disclosed content that the flue gas water intake and dewhitening device disclosed in the present invention, when in use, passes the raw flue gas to be treated into the first-stage sensible heat exchanger, and heat exchange occurs between the raw flue gas and the low-temperature saturated wet flue gas in the first-stage sensible heat exchanger, and the raw flue gas is reduced to about the water dew point. The water vapor in the raw flue gas does not condense or condenses a small amount in the sensible heat exchanger, thereby minimizing the risk of dust accumulation, blockage, scaling, corrosion and other problems in the first-stage sensible heat exchanger. The original flue gas after cooling enters the second-stage latent heat exchanger closely connected at the bottom. The second-stage latent heat exchanger uses cooling water as the refrigerant. The heat exchange tube bundle of the second-stage latent heat exchanger is arranged perpendicular to the flue gas flow direction. Cooling water flows in the heat exchange tube bundle, and flue gas flows outside the heat exchange tube bundle. The cooling water flows through the heat exchange tube and exchanges heat with the flue gas outside the heat exchange tube. The flue gas temperature is further reduced to below the water dew point. The water vapor carried in the flue gas precipitates to form condensed water, and the condensed water enters the recessed part of the pipeline, and the flue gas follows the pipeline along the second flue gas inlet into the first-stage sensible heat exchanger to exchange heat with the original flue gas. The flue gas temperature rises and is then discharged from the chimney to achieve the flue gas whitening effect.

[0032] In the present invention, the original flue gas is reduced to about the water dew point in the first-stage sensible heat exchanger, and the water vapor in the original flue gas does not condense or condenses a small amount in the sensible heat exchanger, thereby minimizing the risk of dust accumulation, blockage, scaling, corrosion and other problems in the first-stage sensible heat exchanger. The present invention adopts a vertical combination of flue gas waste heat recovery and water cooling, which saves floor space, avoids high energy consumption and high investment caused by air cooling, reduces energy consumption, and reduces the probability of dust blockage. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0034] Figure 1 This is a schematic diagram of the main structure of the flue gas water intake and dewhitening device provided by the present invention;

[0035] Figure 2 This is a left-side structural schematic diagram of the flue gas water intake and dewhitening device provided by the present invention.

[0036] in, Figure 1-2 middle:

[0037] A first-stage sensible heat exchanger 1 , a second-stage latent heat exchanger 2 , a pipeline 3 , a recess 301 , a module 201 , a first vertical pipe 302 , a second vertical pipe 303 , an inclined pipe 304 , a horizontal pipe 305 , a demister 4 , and a drain pipe 5 . DETAILED DESCRIPTION

[0038] In order to enable those skilled in the art to better understand the technical solution of the present invention, Figure 1-2 The present invention is further described in detail with specific implementation modes.

[0039] like Figure 1 and 2 As shown, the present invention discloses a flue gas water intake and dewhitening device, wherein the flue gas water intake and dewhitening device comprises a first-stage sensible heat exchanger 1, a second-stage latent heat exchanger 2 and a pipeline 3.

[0040] The first-stage sensible heat exchanger 1 and the second-stage latent heat exchanger 2 are both arranged vertically. It should be noted that the vertical arrangement means that the flue gas inlet channel of the first-stage sensible heat exchanger 1 and the flue gas inlet channel of the second-stage latent heat exchanger 2 are arranged vertically.

[0041] The first-stage sensible heat exchanger 1 and the second-stage latent heat exchanger 2 are arranged in series: the first flue gas outlet of the first-stage sensible heat exchanger 1 is conductively connected with the flue gas inlet of the second-stage latent heat exchanger 2 .

[0042] Two non-interconnected channels are provided in the first-stage sensible heat exchanger 1, wherein the two ends of one channel are the first smoke inlet and the first smoke outlet, respectively, and the two ends of the other channel are the second smoke inlet and the second smoke outlet, respectively. Two channels are also provided in the second-stage latent heat exchanger 2, wherein the two ends of one channel are the smoke inlet and the smoke outlet, respectively, and the other channel is a cooling water channel composed of a heat exchange tube bundle, wherein the two ends are the cooling water outlet and the cooling water inlet, respectively. Specifically, the heat exchange tube bundle of the second-stage latent heat exchanger 2 is arranged perpendicular to the flue gas flow direction in the second-stage latent heat exchanger 2. It should be noted that the heat exchange tube bundle of the second-stage latent heat exchanger 2 can also be arranged to be inclined to the flue gas flow direction in the second-stage latent heat exchanger 2.

[0043] The first flue gas inlet is used to input raw flue gas, and the first flue gas inlet of the first stage sensible heat exchanger 1 is conductively connected to the first flue gas outlet of the first stage sensible heat exchanger 1. Specifically, the raw flue gas is industrial flue gas after flue gas purification (flue gas relative humidity ≤ 95%, temperature 50°C to 150°C).

[0044] The flue gas outlet of the second-stage latent heat exchanger 2 is connected to the second flue gas inlet of the first-stage sensible heat exchanger 1 through the pipe 3, and the second flue gas outlet of the first-stage sensible heat exchanger 1 is used to discharge the treated flue gas. Specifically, the shape of the channel is not limited, and can be any shape that can realize the flue gas outlet of the second-stage latent heat exchanger 2 and the second flue gas inlet of the first-stage sensible heat exchanger 1.

[0045] The first stage sensible heat exchanger 1 is used to reduce the temperature of the original flue gas to the water dew point temperature. Specifically, when in use, the temperature in the first stage sensible heat exchanger 1 can be controlled to reduce the temperature of the original flue gas to a temperature around the water dew point. This makes it so that the water vapor in the flue gas does not condense or condenses a small amount in the first stage sensible heat exchanger 1, and minimizes the risk of dust accumulation, blockage, scaling, corrosion, and other problems in the first stage heat exchanger.

[0046] The second-stage latent heat exchanger 2 is also provided with a cooling water outlet and a cooling water inlet, which are used to introduce cooling water to reduce the temperature of the flue gas passing through the first-stage latent heat exchanger to below the water dew point, so that the water vapor carried in the flue gas is precipitated to form condensed water in the second-stage latent heat exchanger 2. Since the cooling water has a large specific heat, the flue gas temperature at the cooling water outlet of the second-stage latent heat exchanger 2 can be adjusted by adjusting the amount of exchanged water or the water temperature of the cooling water inlet, thereby changing the moisture content of the exhaust smoke to meet the de-whitening requirements under different ambient temperatures and ambient humidity.

[0047] The pipeline 3 is provided with a recess 301 capable of containing the condensate condensed by the second-stage latent heat exchanger 2 , so that the condensate condensed by the second-stage latent heat exchanger 2 can be collected into the recess 301 .

[0048] Specifically, the shape of the recess 301 is not limited, and may be a regular shape such as an arc, a triangle, or an irregular shape.

[0049] In some embodiments, the present invention discloses that the first-stage sensible heat exchanger 1 is a plate heat exchanger, specifically, a cross-flow gas-gas plate heat exchanger.

[0050] Furthermore, the present invention discloses that the second-stage latent heat exchanger 2 is a metal fin radiator, a fluoroplastic steel heat exchanger or a fluoroplastic heat exchanger. The fins of the metal fin radiator are made of stainless steel, aluminum alloy or ND steel.

[0051] Specifically, for the flue gas after passing through the industrial flue gas purification device for efficient and synergistic removal of multiple pollutants, the concentration of corrosive gases in the flue gas is extremely low. In this case, a metal fin heat exchanger is used, and the fins are made of 304 stainless steel, aluminum alloy, ND steel or 316L stainless steel; for the flue gas after using the flue gas purification device such as wet desulfurization, the flue gas still contains a certain concentration of acidic gases such as SO3, HF, HCl, etc. In this case, a metal fin heat exchanger is used, and the fins and the base pipes in contact with the flue gas are made of highly corrosion-resistant 2205 stainless steel or 2507 stainless steel, etc., and more corrosion-resistant fluoroplastic steel heat exchangers, fluoroplastic heat exchangers, etc. can also be used.

[0052] In some embodiments, the present invention specifically discloses that the second-stage latent heat exchanger 2 is a water-cooled tubular heat exchanger, which is detachably assembled through preset modules 201 .

[0053] In some embodiments, the present invention discloses that the second-stage latent heat exchanger 2 is assembled longitudinally by modules 201. That is, the water-cooled tubular heat exchanger adopts a modular 201 heat exchange tube bundle design, and the number of modules 201 of the heat exchange tube bundle can be increased or decreased in the longitudinal direction to meet the requirements of different application environments without increasing the floor space.

[0054] In some embodiments, the present invention specifically discloses that the pipeline 3 includes a first vertical pipe 302, a second vertical pipe 303, an inclined pipe 304 and a horizontal pipe 305. The inlet of the first vertical pipe 302 is conductively connected to the flue gas outlet of the second-stage latent heat exchanger 2, the outlet of the first vertical pipe 302 is conductively connected to the inlet of the inclined pipe 304, the outlet of the inclined pipe 304 is conductively connected to the inlet of the second vertical pipe 303, the outlet of the second vertical pipe 303 is conductively connected to the second flue gas inlet of the first-stage sensible heat exchanger 1, the inclined pipe 304 is inclined at a preset angle to the horizontal plane, and the recess 301 is formed by the intersection of the inclined pipe 304 and the first vertical pipe 302.

[0055] Furthermore, the present invention discloses a preset angle greater than or equal to 5° and less than or equal to 10°. After many hard experiments, the inventors of the present invention have found that the effect of collecting condensed water is best when the preset angle is within this range.

[0056] It should be noted that the structure of the pipeline 3 is not limited to the structure including the first vertical pipe 302, the second vertical pipe 303, the inclined pipe 304 and the horizontal pipe 305, and can also be composed of the inclined pipe 304 and the arc pipe, or other regular or irregular shaped pipes.

[0057] In some embodiments, the present invention discloses that the flue gas water intake and desulfurization device also includes a demister 4, which is installed in the second vertical pipe 303. Specifically, the demister 4 is close to the bottom end of the second vertical pipe 303 and is used to further capture and recover droplets carried by the flue gas. The recovered droplets flow from the second vertical pipe 303 into the recess 301 of the inclined pipe 304 under the action of gravity.

[0058] In some embodiments, the present invention discloses that the demister 4 is a wire mesh demister 4, a baffle demister 4, a ridge demister 4 or a tube bundle demister 4, etc. It should be noted that the demister 4 may also be other high-efficiency demister devices.

[0059] In some embodiments, the present invention discloses a flue gas water intake and dewhitening device further comprising a drain pipe 5, the inlet of which is connected to the bottom end of the recess 301 and discharged after being collected in the drain pipe 5. Specifically, the drain pipe 5 is arranged at the lowest position of the recess 301 to facilitate the discharge of condensed water from the recess 301.

[0060] In order to facilitate the control of the drainage pipe 5 to discharge condensed water, the present invention discloses that a switch valve is arranged on the drainage pipe 5 .

[0061] The flue gas water intake and dewhitening device disclosed in the present invention, when in use, passes the raw flue gas to be treated into the first-stage sensible heat exchanger 1, and heat exchange occurs between the raw flue gas and the low-temperature saturated wet flue gas in the first-stage sensible heat exchanger 1, and the raw flue gas is reduced to about the water dew point, and the water vapor in the raw flue gas does not condense or condenses a small amount in the first-stage sensible heat exchanger 1, thereby minimizing the risks of dust accumulation, blockage, scaling, corrosion and other problems in the first-stage sensible heat exchanger 1. The original flue gas after cooling enters the second-stage latent heat exchanger 2 closely connected at the bottom. The second-stage latent heat exchanger 2 uses cooling water as the refrigerant. The heat exchange tube bundle of the second-stage latent heat exchanger 2 is arranged perpendicular to the flue gas flow direction. Cooling water flows in the heat exchange tube bundle, and flue gas flows outside the heat exchange tube bundle. The cooling water flows through the heat exchange tube and exchanges heat with the flue gas outside the heat exchange tube. The flue gas temperature is further reduced to below the water dew point. The water vapor carried in the flue gas precipitates to form condensed water, and the condensed water enters the recess 301 of the pipe 3. The flue gas passes through the demister 4 along the pipe 3 to further capture and recover the droplets carried by the flue gas. The recovered droplets flow from the second vertical pipe 3 into the recess 301 of the inclined pipe 304 under the action of gravity, and are collected and discharged through the drain pipe 5. The flue gas enters the first-stage sensible heat exchanger 1 along the second flue gas inlet, exchanges heat with the original flue gas, and the flue gas temperature rises, and then is discharged from the chimney to achieve the flue gas dewhitening effect.

[0062] In the present invention, since the original flue gas is reduced to about the water dew point in the first-stage sensible heat exchanger 1, the water vapor in the original flue gas does not condense or condenses a small amount in the sensible heat exchanger, thereby minimizing the risk of dust accumulation, blockage, scaling, corrosion and other problems in the first-stage sensible heat exchanger 1. The present invention adopts a vertical combination of recovering flue gas waste heat and water cooling, which saves floor space, avoids high energy consumption and high investment caused by air cooling, reduces energy consumption, and reduces the probability of dust blockage.

[0063] The industrial flue gas dewhitening device disclosed in the present invention is used for dewhitening of the flue gas in a chemical park, and the flue gas volume is 50000m 3 / h, original flue gas relative humidity 90%, original flue gas temperature 55℃. SO2 concentration in original flue gas ≤35mg / Nm 3 , NOx concentration ≤50mg / Nm 3 , smoke concentration ≤5mg / Nm 3 .

[0064] The flue gas water extraction and dewhitening device of the present invention is adopted. The first-stage sensible heat exchanger 1 is an air-to-air plate heat exchanger, and the heat exchange element is made of 316L material. The second-stage latent heat exchanger 2 is a finned heat exchanger, and the fins and base tubes are made of 316L material. The overall area is about 17m 2 , saving nearly 40% of the floor space compared with conventional de-whitening devices. Table 1 shows the main parameters of the flue gas water de-whitening device.

[0065] Table 1

[0066]

[0067] After being treated by the flue gas water dewhitening device, the flue gas temperature is reduced by 10°C, but the relative humidity is reduced from 90% to 29%. About 3.8 tons of water vapor can be recovered per hour, which greatly reduces the risk of white smoke in low or high temperature environments in winter. The main parameters of each flue gas before and after treatment are shown in Table 2 below.

[0068] Table 2

[0069]

[0070] In the present invention, "first", "second" and so on are used for description only and have no other special meanings.

[0071] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and inventive features disclosed herein.

Claims

1. A flue gas water extraction and dewhitening device, characterized in that: It includes a first-stage sensible heat exchanger, a second-stage latent heat exchanger and pipelines; The first-stage sensible heat exchanger and the second-stage latent heat exchanger are both vertical and arranged in a row. The smoke inlet channel of the first-stage sensible heat exchanger and the smoke inlet channel of the second-stage latent heat exchanger are arranged vertically. The first-stage sensible heat exchanger is an air-to-air heat exchanger, and the first smoke inlet of the first-stage sensible heat exchanger is used to input raw smoke. The first smoke outlet of the first-stage sensible heat exchanger is conductively connected to the smoke inlet of the second-stage latent heat exchanger, and the smoke outlet of the second-stage latent heat exchanger is conductively connected to the second smoke inlet of the first-stage sensible heat exchanger through a pipeline. The second smoke outlet of the first-stage sensible heat exchanger is used to discharge the treated smoke. The first stage sensible heat exchanger is used to reduce the temperature of the raw flue gas to the water dew point temperature; The second-stage latent heat exchanger is also provided with a cooling water outlet and a cooling water inlet for introducing cooling water to reduce the temperature of the flue gas passing through the second-stage latent heat exchanger to a temperature below the water dew point; The pipeline is provided with a recessed portion capable of holding condensate condensed by the second-stage latent heat exchanger; The second-stage latent heat exchanger is composed of preset modules that can be disassembled and assembled; The second-stage latent heat exchanger is formed by assembling the modules in the longitudinal direction; The pipeline includes a first vertical pipe, a second vertical pipe, an inclined pipe and a horizontal pipe; the inlet of the first vertical pipe is conductively connected to the smoke outlet of the second-stage latent heat exchanger, the outlet of the first vertical pipe is conductively connected to the inlet of the inclined pipe, the outlet of the inclined pipe is conductively connected to the inlet of the second vertical pipe, and the outlet of the second vertical pipe is conductively connected to the second smoke inlet of the first-stage sensible heat exchanger; the inclined pipe is inclined at a preset angle to the horizontal plane, and the concave portion is formed by the intersection of the inclined pipe and the first vertical pipe; The flue gas water intake and desulfurization device also includes a demister; the demister is installed in the second vertical pipe.

2. The flue gas water intake and dewhitening device according to claim 1, characterized in that: It also includes drains; The inlet of the drain pipe is conductively connected to the bottom end of the recess.

3. The flue gas water intake and dewhitening device according to claim 2, characterized in that: The drain pipe is provided with a switch valve.

4. The flue gas water extraction and dewhitening device according to any one of claims 1 to 3, characterized in that: The second-stage latent heat exchanger is a metal fin radiator, a fluoroplastic steel heat exchanger or a fluoroplastic heat exchanger.

5. The flue gas water intake and dewhitening device according to claim 4, characterized in that: The fins of the metal fin heat sink are made of stainless steel, aluminum alloy or ND steel.

6. The flue gas water intake and dewhitening device according to claim 1, characterized in that: The demister is a wire mesh demister, a baffle demister, a ridge demister or a tube bundle demister; and / or The preset angle is greater than or equal to 5° and less than or equal to 10°; and / or The first-stage sensible heat exchanger is a plate heat exchanger; and / or The heat exchange tube bundle of the second-stage latent heat exchanger is arranged perpendicular to the flue gas flow direction in the second-stage latent heat exchanger.

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