Two-stage variable-temperature white smoke elimination device based on flue gas waste heat

Abstract

The utility model belongs to the field of power plant smoke plume treatment, and particularly relates to a two-stage variable-temperature white smoke elimination device based on smoke waste heat. The system mainly comprises a desulfurization tower for flue gas desulfurization, a primary heating heat exchanger arranged between an original flue gas pipeline and the desulfurization tower, and a spraying type flue gas absorber connected with the desulfurization tower and the primary heating heat exchanger at the same time, the two-stage variable-temperature white smoke elimination device further comprises a solution converter connected with the first-stage heating heat exchanger and a condenser connected with the solution converter. And a secondary cooling heat exchanger for reducing the temperature of the regenerated concentrated solution is also arranged between the solution converter and the spraying type flue gas absorber. According to the two-stage variable-temperature white smoke elimination device based on the flue gas waste heat, the efficiency of converting a dilute solution into a concentrated solution can be improved; meanwhile, the temperature difference between the concentrated solution and the flue gas is increased, and the white smoke elimination efficiency of the concentrated solution on the flue gas is improved. The white elimination requirement of the power plant can be better met, and the environment image of the power plant is improved.

Description

Technical Field

[0001] The utility model belongs to the field of power plant plume treatment, and particularly relates to a two-stage variable-temperature plume elimination device. Background Art

[0002] White plume refers to the smoke plume continuously discharged from the chimney, which gets its name because of its feather-like shape, and is also called wet plume in the industry. The white smoke discharged from the chimney mixes with the ambient cold air. During the cooling process, the contained water vapor is saturated and condensed, and the condensed water mist droplets refract and scatter light, making the plume appear white or gray. Plume elimination refers to the action of eliminating the white plume, which is an essential work for the treatment of the power plant production environment. Its purpose is to reduce the water vapor saturation of the finally discharged flue gas relative to the air, and avoid the supersaturation condensation of the water vapor therein into small droplets to form a white plume. The existing plume elimination means usually reduce the relative moisture content by increasing the temperature of the discharged flue gas. The reduction of its moisture content relative to the air can make the water vapor in the flue gas not easily saturated and condensed when discharged, so as to eliminate the white plume; or directly reduce the absolute moisture content of the discharged flue gas to achieve the elimination of the white plume. For example, the Chinese patent document with the publication number CN111174225A discloses a wet plume elimination system and method based on solution humidity adjustment and water recovery, and this method uses the design idea of reducing the absolute moisture content of the flue gas described above. Specifically, the system is provided with a spray tower, a dehumidifier, an aqueous solution heat exchanger, a regenerator, a solution storage tank, a fan, and various circulating pumps and regulating valves. It uses the circulating water in the spray tower to condense and dehumidify the flue gas to a saturated state, and then uses the salt solution in the dehumidifier to deeply dehumidify the flue gas to reduce the moisture content of the flue gas for plume elimination.

[0003] Although the above system and method can complete the plume elimination work to a certain extent, during the salt solution circulation process, the dilute solution after deeply dehumidifying the flue gas will be reconverted into a concentrated solution in the regenerator. During this process, it will contact the outdoor air sent into the regenerator by the exhaust fan to realize the separation of water in the dilute solution; in the above solution, this process does not experience additional heating and reheating, so the regeneration conversion efficiency of the salt solution often cannot reach a very high level. In addition, the concentrated solution output from the regenerator also undergoes a heating and heat exchange process before entering the dehumidifier, which reduces the temperature difference between the concentrated solution and the flue gas, and is also not conducive to improving the deep dehumidification efficiency of the flue gas, ultimately resulting in the problem of low overall plume elimination efficiency. Summary of the Utility Model

[0004] The purpose of the utility model is to provide a two-stage variable-temperature plume elimination device based on the waste heat of the flue gas, which can improve the conversion efficiency of the dilute solution into the concentrated solution; at the same time, widen the temperature difference between the concentrated solution and the flue gas, and improve the plume elimination efficiency of the concentrated solution for the flue gas. It can better meet the plume elimination requirements of the power plant and improve the environmental image of the power plant.

[0005] To achieve the above object, the specific solution adopted is as follows: A two-stage variable-temperature white smoke elimination device based on flue gas waste heat, comprising a desulfurization tower for flue gas desulfurization, characterized in that it further comprises a primary heating heat exchanger arranged between the raw flue gas pipeline and the desulfurization tower, and a spray-type flue gas absorber connected to both the desulfurization tower and the primary heating heat exchanger; this two-stage variable-temperature white smoke elimination device further comprises a solution converter connected to the primary heating heat exchanger and a condenser connected to the solution converter; a secondary cooling heat exchanger for reducing the temperature of the regenerated concentrated solution is also arranged between the solution converter and the spray-type flue gas absorber.

[0006] Thus, the raw flue gas pipeline is the pipeline for discharging the original sulfur-containing flue gas. According to the requirements of the industrial production environment management regulations, this sulfur-containing flue gas is prohibited from being directly discharged, so it needs to be desulfurized. The temperature of the original sulfur-containing flue gas is relatively high. After passing through the desulfurization tower, the temperature drops, but the water vapor contained in it is in a saturated state, so direct discharge will produce a white smoke phenomenon.

[0007] The raw flue gas pipeline is connected to the flue gas side inlet of the primary heating heat exchanger, and then the original sulfur-containing flue gas is transported to the desulfurization tower through the flue gas side outlet. During this process, part of the heat of the original sulfur-containing flue gas is transferred to the primary heating heat exchanger.

[0008] The desulfurization tower desulfurizes the original sulfur-containing flue gas. The desulfurized flue gas enters the spray-type flue gas absorber. At the same time as the desulfurized flue gas enters, there is also a concentrated solution to be reacted at a relatively low temperature. When the concentrated solution to be reacted at a relatively low temperature is sprayed out from the upper part of the spray-type flue gas absorber, the small droplets of the concentrated solution will come into contact with the desulfurized flue gas, absorb the water molecules in it, and release heat during this process. This heat can heat the desulfurized flue gas. At this time, when passing through the spray-type flue gas absorber, the temperature of the desulfurized flue gas rises, the moisture content decreases, and both the relative saturation and the absolute saturation decrease significantly. When it is discharged from the flue gas outlet of the spray-type flue gas absorber, white smoke will no longer be generated.

[0009] After the above process, the concentrated solution to be reacted absorbs the moisture in the flue gas through reaction and then becomes a first high-temperature dilute solution. The first high-temperature dilute solution needs to be regenerated in a subsequent cycle and dehydrated again to become a concentrated solution to be reacted at a low temperature.

[0010] At this time, the first high-temperature dilute solution in the spray-type flue gas absorber will be transported to the primary heating heat exchanger. The primary heating heat exchanger is arranged between the raw flue gas pipeline and the desulfurization tower. When the first high-temperature dilute solution passes through, it can absorb heat from the higher-temperature original sulfur-containing flue gas through the heat exchange device and become a second high-temperature dilute solution. That is, the temperature of the second high-temperature dilute solution is higher than that of the first high-temperature dilute solution.

[0011] Next, the second high-temperature dilute solution is transported to the solution converter and sprayed. The solution converter is connected to a condenser, which is used to condense the water vapor in the solution converter into liquid water to maintain a lower water vapor partial pressure in the solution converter. Since the first high-temperature dilute solution is heated to a higher temperature to form the second high-temperature dilute solution when passing through the first-stage heating heat exchanger, the water vapor partial pressure of the second high-temperature dilute solution is relatively high. During solution regeneration, the dehydration efficiency of the solution is higher, that is, the efficiency of generating the low-temperature concentrated solution is higher. After dehydration, the temperature of the second high-temperature dilute solution decreases and becomes a low-temperature concentrated solution, which will be re-transported from the solution converter to the spray-type flue gas absorber to participate in the next whitening elimination reaction.

[0012] Next, in this device, a second-stage cooling heat exchanger for reducing the temperature of the regenerated concentrated solution is also provided between the solution converter and the spray-type flue gas absorber. That is, when the low-temperature concentrated solution passes through the second-stage cooling heat exchanger, it will perform secondary cooling to form the above-mentioned low-temperature concentrated solution to be reacted, that is, the temperature of the low-temperature concentrated solution to be reacted is lower than that of the low-temperature concentrated solution output from the solution converter. This increases the temperature difference and water vapor partial pressure difference with the desulfurized flue gas, thereby improving the reaction efficiency during whitening elimination and enhancing the whitening elimination efficiency.

[0013] In summary, through the settings of the first-stage heating heat exchanger and the second-stage cooling heat exchanger, this device respectively uses the high temperature of the original sulfur-containing flue gas and external cooling measures to reheat the first high-temperature dilute solution and re-cool the low-temperature concentrated solution, thereby forming a low-temperature concentrated solution to be reacted with a large temperature difference from the desulfurized flue gas, and then fully releasing the water absorption and heat release potential of the low-temperature concentrated solution to be reacted, improving the whitening elimination efficiency. Moreover, when the first high-temperature dilute solution absorbs heat and transforms into the second high-temperature dilute solution, it directly extracts heat from the original sulfur-containing flue gas without adding additional heating devices, saving additional energy consumption. While reducing the overall energy loss of the device, it also improves the conversion efficiency of the dilute-concentrated solution, further enhancing the operating efficiency of the entire device. In addition, a first-stage heating heat exchanger is provided between the original flue gas pipeline and the desulfurization tower. Since the temperature of the original sulfur-containing flue gas is relatively high, it loses some heat through the heat exchange step when passing through the first-stage heating heat exchanger, resulting in a decrease in its own temperature. When the cooled flue gas passes through the desulfurization tower, compared with the original high-temperature flue gas, the amount of water carried out will be reduced, thereby reducing the water absorption pressure of the spray-type flue gas absorber on the flue gas and indirectly improving the whitening elimination efficiency.

[0014] This device has excellent temperature conversion ability for high and low concentration salt solutions, high conversion efficiency, and strong whitening elimination ability for flue gas. It can meet the whitening elimination requirements of power plants and enhance the environmental image of power plants.

[0015] As a preferred embodiment of the present invention, the condenser comprises a negative pressure tank body communicated with the solution converter and a condensation pipeline installed inside the negative pressure tank body; the condensation pipeline is connected to an external condensation water circulation loop.

[0016] Therefore, the negative pressure tank body of the condenser is connected with the solution converter. The negative pressure tank body is a container body whose internal air pressure is lower than the external standard atmospheric pressure. When it is connected with the solution converter, since the gas pressure in the solution converter is greater than that in the condenser, under the action of the pressure difference, the separated water vapor in the solution converter can flow autonomously and continuously into the negative pressure tank body of the condenser. Then, after the water vapor contacts the condensation pipeline, it condenses into liquid water and is deposited at the bottom of the negative pressure tank body waiting to be discharged. The condensation pipeline is connected to the external condensation water circulation loop. In addition, this negative pressure environment will directly promote the separation of salt solution and water in the second high-temperature dilute solution sprayed in the solution converter connected to it. Specifically, due to the high temperature and large water content of the second high-temperature dilute solution, the water molecules in the small liquid droplets formed after spraying are more easily converted into water vapor under the action of the negative pressure environment, thereby realizing the separation of water and solution. Due to the existence of the negative pressure environment and the pressure of the condenser is lower than the pressure of the solution converter, the separated water will enter the condenser in the form of water vapor, and the dilute solution of the separated part of the water becomes a concentrated solution and falls to the bottom of the solution converter. Moreover, due to the phase change of water in the above separation process (liquid water becomes water vapor), the heat of the second high-temperature dilute solution is absorbed, so the temperature of the concentrated solution deposited below is reduced.

[0017] As a preferred embodiment of the present invention, the condenser further comprises an air pump connected to the negative pressure tank body for removing non-condensable gas to maintain a negative pressure environment and a drain valve for draining water.

[0018] Therefore, the vacuum pump is used to extract the non-condensable gas in the negative pressure tank to maintain the negative pressure environment therein; a drain valve is provided at the bottom of the negative pressure tank to discharge the condensed liquid water in time to avoid the reduction of condensation efficiency due to rising water level and potential reflux of liquid water to the solution converter.

[0019] As a preferred embodiment of the utility model, the two-stage variable temperature desulphurization device further comprises a concentrated solution replenishing pump connected to the solution converter; the concentrated solution replenishing pump is used to pump concentrated solution into the solution converter.

[0020] Therefore, in the actual desulfurization operation, when the low-temperature concentrated solution to be reacted is subjected to absorption reaction with the desulfurized flue gas in the spray-type flue gas absorber, part of the solution will inevitably be taken away due to the fast discharge speed of the desulfurized flue gas. That is, the amount of solution involved in the circulation in the entire device will continue to be lost. Therefore, a concentrated solution replenishment pump connected to the solution converter is set to regularly replenish the concentrated solution raw materials therein to maintain the stable working state of the entire device.

[0021] Preferably, a first circulation pump is provided between the solution converter and the secondary cooling heat exchanger, and the first circulation pump is used to continuously pump the low-temperature concentrated solution in the solution converter into the secondary cooling heat exchanger.

[0022] Thus, the first circulation pump will provide the driving force for the solution circulation in the pipeline, so that the already generated low-temperature concentrated solution in the solution converter can be discharged in time and enter the secondary cooling heat exchanger to participate in secondary cooling, which ensures the continuous accommodation capacity of the solution converter and the heat exchange efficiency of the secondary cooling heat exchanger; it also enables the low-temperature concentrated solution to be reacted and output from the secondary cooling heat exchanger to the spray-type flue gas absorber to obtain sufficient power, ensuring that the subsequent spraying in the spray-type flue gas absorber can proceed normally and continuously.

[0023] Preferably, a second circulation pump is provided between the primary heating heat exchanger and the spray-type flue gas absorber, and the second circulation pump is used to continuously pump the first high-temperature dilute solution at the bottom of the spray-type flue gas absorber into the primary heating heat exchanger.

[0024] Thus, the second circulation pump will provide the driving force for the solution circulation in the pipeline, so that the already generated first high-temperature dilute solution in the spray-type flue gas absorber can be discharged in time and enter the primary heating heat exchanger to participate in secondary heating, which ensures the continuous accommodation capacity of the spray-type flue gas absorber and the heat exchange efficiency of the primary heating heat exchanger; it also enables the second high-temperature dilute solution output from the primary heating heat exchanger to the solution converter to obtain sufficient power, ensuring that the subsequent spraying in the solution converter can proceed normally and continuously.

[0025] Preferably, this two-stage variable-temperature white elimination device further includes a first solution molecular adsorber connected to the air extraction pump and a second solution molecular adsorber connected to the drain valve.

[0026] Since the salt solution used in the entire circulation device is an industrial raw material, which has direct or indirect toxicity, and it is inevitable that the air extraction pump will carry away trace salt solution droplet molecules and discharge them into the air when working. Therefore, in order to meet the environmental protection requirements of industrial production, a first solution molecular adsorber is connected and provided at the air extraction pump, which can select a chemical reaction absorption device in the prior art to adsorb the carried-away salt solution and protect the environment. Similarly, the drain valve also has potential water pollution problems, so a second solution molecular adsorber is specially provided to meet the discharge requirements of liquid water.

[0027] Preferably, a first thermometer is installed between the primary heating heat exchanger and the solution converter; a second thermometer is installed between the secondary cooling heat exchanger and the spray-type flue gas absorber.

[0028] Since the temperature of the second high-temperature dilute solution passing through the first-stage heating heat exchanger is related to the subsequent dilute-concentrated conversion efficiency, and the temperature of the low-temperature concentrated solution to be reacted passing through the second-stage cooling heat exchanger is related to the subsequent white elimination efficiency, and the above relationships can be quantified through laboratory simulation. Therefore, setting the first thermometer and the second thermometer can simultaneously monitor the solution temperatures of the above two paths respectively. Combining the quantification results of laboratory simulation, the white elimination ability of the entire device can be controlled. The staff can manage the working state of the entire device through the real-time monitoring values of the first thermometer and the second thermometer.

[0029] As a preference of the present utility model, the second-stage cooling heat exchanger is connected to the external condensed water circulation loop.

[0030] Thus, the second-stage cooling heat exchanger can be connected in parallel with the condensation pipeline of the condenser to the external condensed water circulation loop, thereby simplifying the structure of the entire device, reducing the occupied space, and saving costs.

[0031] In summary, the present utility model has the following beneficial effects:

[0032] 1. Through the setting of the first-stage heating heat exchanger and the second-stage cooling heat exchanger, by means of the high temperature of the original sulfur-containing flue gas and the external cooling measures respectively, the first high-temperature dilute solution is heated again and the low-temperature concentrated solution is cooled again, so as to form a low-temperature concentrated solution to be reacted with a large temperature difference and water vapor partial pressure difference from the desulfurized flue gas, and then fully release the water absorption and heat release potential of the low-temperature concentrated solution to be reacted, and improve the white elimination efficiency.

[0033] 2. When the first high-temperature dilute solution absorbs heat and turns into the second high-temperature dilute solution, it directly extracts heat from the original sulfur-containing flue gas without adding an additional heating device, saving additional energy consumption. While reducing the overall energy loss of the device, it also improves the conversion efficiency of the dilute-concentrated solution, and further improves the operation efficiency of the entire device. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic structural diagram of the device.

[0035] In the figure: desulfurization tower 1, first-stage heating heat exchanger 2, spray-type flue gas absorber 3, solution converter 4, condenser 5, negative pressure tank body 51, condensation pipeline 52, drain valve 53, second-stage cooling heat exchanger 6, concentrated solution makeup pump 7, first circulation pump 8, second circulation pump 9, air extraction pump 10, original flue gas pipeline a, flue gas discharge port b, external condensed water circulation loop inlet c, external condensed water circulation loop outlet d, exhaust port e, drain port f, concentrated solution makeup port g. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0036] The preferred embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Anyone can implement the present disclosure in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to make the present disclosure more thorough and complete, and to fully convey the scope of the present disclosure to those skilled in the art.

[0037] As used herein, the term "including" and its variations mean open inclusion, i.e., "including but not limited to". Unless otherwise stated, the term "or" means "and / or". The term "based on" means "based at least in part on". The terms "an example embodiment" and "an embodiment" mean "at least one example embodiment". The term "another embodiment" means "at least one additional embodiment".

[0038] like Figure 1 As shown, in this embodiment, the original flue gas duct a is connected to the flue gas side inlet of the primary temperature rising heat exchanger 2, the flue gas side outlet of the primary temperature rising heat exchanger 2 is connected to the flue gas inlet of the desulfurization tower 1, the flue gas outlet of the desulfurization tower 1 is connected to the flue gas inlet of the spray type flue gas absorber 3, and the flue gas after desulfurization treatment is discharged through the flue gas outlet b. A first high-temperature dilute solution discharge port is provided at the bottom of the spray-type flue gas absorber 3, and the discharge port is connected to the second circulation pump 9 via a pipeline. The second circulation pump 9 is also connected to the solution side inlet of the first-stage temperature-raising heat exchanger 2, and the solution side outlet of the first-stage temperature-raising heat exchanger 2 is connected to the dilute solution input port of the solution converter 4; a sprayer connected to the dilute solution input port is provided inside the solution converter 4, and a low-temperature concentrated solution storage tank is provided at the bottom thereof, and the low-temperature concentrated solution storage tank is connected to the concentrated solution output port of the solution converter 4, and the concentrated solution output port of the solution converter 4 is connected to the first circulation pump 8, and the first circulation pump 8 is connected to the low-temperature concentrated solution input port of the second-stage temperature-lowering heat exchanger 6, and the low-temperature concentrated solution output port to be reacted of the second-stage temperature-lowering heat exchanger 6 is connected to the low-temperature concentrated solution input port to be reacted of the spray-type flue gas absorber 3. The solution converter 4 is also connected to the condenser 5 through a connecting pipe. A condensation pipeline 52 is provided in the negative pressure tank 51 of the condenser 5, a vacuum pump 10 is provided on the top, and a drain valve 53 is provided on the bottom. The condensation pipeline 52 is respectively connected to the inlet c of the external condensation water circulation loop and the outlet d of the external condensation water circulation loop. Similarly, the condensation pipeline of the secondary cooling heat exchanger 6 is also connected to the inlet c of the external condensation water circulation loop and the outlet d of the external condensation water circulation loop.

[0039] In addition, the vacuum pump 10 is connected to the first solution molecule adsorber, and then connected to the exhaust port e, and the drain valve 53 is connected to the second solution molecule adsorber, and then connected to the drain port f.

[0040] A first thermometer is installed between the solution side outlet of the first-stage heating heat exchanger 2 and the dilute solution inlet of the solution converter 4; a second thermometer is provided between the output port of the low-temperature concentrated solution to be reacted of the second-stage cooling heat exchanger 6 and the input port of the low-temperature concentrated solution to be reacted of the spray-type flue gas absorber 3.

[0041] The solution converter 4 is also connected to the pump outlet end of the concentrated solution supply pump 7, and the pump inlet end of the concentrated solution supply pump 7 is connected to the concentrated solution supply port g.

[0042] During the de-white reaction, the raw sulfur-containing flue gas is input from the raw flue gas pipeline a, passes through the flue gas side inlet and the flue gas side outlet of the first-stage heating heat exchanger 2, and then enters the desulfurization tower 1 from the flue gas inlet of the desulfurization tower 1 for desulfurization reaction. After that, the desulfurized flue gas enters the spray-type flue gas absorber 3 through the flue gas outlet of the desulfurization tower 1 and the flue gas inlet of the spray-type flue gas absorber 3.

[0043] Synchronously, the low-temperature concentrated solution to be reacted enters from the input port of the low-temperature concentrated solution to be reacted of the spray-type flue gas absorber 3, and then is sprayed by the sprayer to form small droplets and fall naturally. Then it contacts the desulfurized flue gas, absorbs the water molecules in it, and releases heat during this process. This heat can heat the desulfurized flue gas. At this time, when passing through the spray-type flue gas absorber 3, the temperature of the desulfurized flue gas rises, the moisture content decreases, and both the relative saturation and the absolute saturation decrease significantly. When it is discharged from the flue gas discharge port b of the spray-type flue gas absorber 3, white plume will no longer be generated.

[0044] Due to absorbing the moisture in the flue gas, the low-temperature concentrated solution to be reacted is transformed into the first high-temperature dilute solution and deposited at the bottom of the spray-type flue gas absorber 3. Then the first high-temperature dilute solution flows through the first high-temperature dilute solution discharge port at the bottom to the second circulation pump 9. The second circulation pump 9 pumps the first high-temperature dilute solution into the first-stage heating heat exchanger 2. Here, the first high-temperature dilute solution will absorb the heat from the raw sulfur-containing flue gas and heat up to form the second high-temperature dilute solution. Then it enters the solution converter 4 through the solution side outlet of the first-stage heating heat exchanger 2 and the dilute solution inlet of the solution converter 4, and then is sprayed by the sprayer. Since the water vapor partial pressure of the second high-temperature dilute solution is relatively large, and the solution converter 4 is connected to the condenser 5, and the condenser 5 is in a negative pressure environment, this environment causes the water in the second high-temperature dilute solution in the solution converter 4 to be separated out and enter the negative pressure tank body 51 in the form of water vapor. At this time, the condensation pipeline 52 in the negative pressure tank body 51 will condense this water vapor to make it turn into liquid water and discharge it through the drain valve 53. The condensed water in the condensation pipeline 52 enters from the external condensation water circulation loop inlet c and is discharged from the external condensation water circulation loop outlet d. The air extraction pump 10 on the negative pressure tank body 51 is used to extract the non-condensable gas in the negative pressure tank body 51 to maintain the negative pressure environment therein.

[0045] In the solution converter 4, when the second high-temperature dilute solution is dehydrated, the process of liquid water turning into water vapor will take away part of the heat, causing the second high-temperature dilute solution to become a low-temperature concentrated solution and deposit in the low-temperature concentrated solution storage pool below the solution converter 4. Then, the low-temperature concentrated solution will flow through the concentrated solution outlet of the solution converter 4 to the first circulation pump 8, and then be pumped by the first circulation pump 8 to the low-temperature concentrated solution inlet of the secondary cooling heat exchanger 6. The condensation pipeline of the secondary cooling heat exchanger 6 is connected to the external condensation water circulation loop inlet c and the external condensation water circulation loop outlet d. The low-temperature concentrated solution will complete cooling here to form a lower-temperature low-temperature concentrated solution to be reacted, and then flow to the spray-type flue gas absorber 3 to complete the next cycle. Under the continuous pumping of the first circulation pump 8 and the second circulation pump 9, the entire circulation continuously operates to achieve continuous white elimination work.

[0046] New concentrated solution can be regularly supplemented to the solution converter 4 through the concentrated solution replenishment port g and the concentrated solution replenishment pump 7 to make up for the salt solution lost at the spray-type flue gas absorber 3.

[0047] In addition, since the salt solution used in the entire circulation device is an industrial raw material, it has direct or indirect toxicity, and the air extraction pump 10 will inevitably carry away trace salt solution droplet molecules and discharge them into the air during operation. Therefore, in order to meet the environmental protection requirements of industrial production, a first solution molecule adsorber is connected and provided at the air extraction pump 10, which can select a chemical reaction absorption device in the prior art to adsorb the carried-away salt solution and protect the environment. Similarly, there is also a potential water pollution problem with the drain valve 53, so a second solution molecule adsorber is specially provided to meet the discharge requirements of liquid water.

[0048] Since the temperature of the second high-temperature dilute solution passing through the primary heating heat exchanger 2 is related to the subsequent dilute-concentrated conversion efficiency, and the temperature of the low-temperature concentrated solution to be reacted passing through the secondary cooling heat exchanger 6 is related to the subsequent white elimination efficiency, and the above relationships can be quantified through laboratory simulation. Therefore, a first thermometer and a second thermometer are set to simultaneously monitor the solution temperatures of the above two paths respectively. Combining the quantified results of laboratory simulation, the white elimination ability of the entire device can be controlled. The staff can manage the working state of the entire device through the real-time monitoring values of the first thermometer and the second thermometer.

[0049] The salt solution in this embodiment is a commonly used choice well-known to those skilled in the art, such as calcium chloride solution, which will not be elaborated here.

[0050] Multiple embodiments of the present disclosure have been described above. The above description is exemplary and not exhaustive, and is also not limited to the disclosed embodiments. Many modifications and variations are obvious to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The choice of terms used herein is intended to best explain the principles of the embodiments, the practical application, or the improvement of the technology in the market, or to enable other ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A two-stage temperature-variable desulfurization device based on flue gas waste heat, comprising a desulfurization tower (1) for flue gas desulfurization, characterized in that: It also includes a primary temperature rising heat exchanger (2) arranged between the original flue gas pipeline and the desulfurization tower (1) and a spray type flue gas absorber (3) connected to both the desulfurization tower (1) and the primary temperature rising heat exchanger (2); the two-stage temperature variable desulphurization device also includes a solution converter (4) connected to the primary temperature rising heat exchanger (2) and a condenser (5) connected to the solution converter (4); a secondary temperature falling heat exchanger (6) for reducing the temperature of the concentrated solution after regeneration is also arranged between the solution converter (4) and the spray type flue gas absorber (3).

2. A two-stage temperature-variable deoxidation device based on flue gas waste heat according to claim 1, characterized in that: The condenser (5) comprises a negative pressure tank body (51) connected to the solution converter (4) and a condensation pipeline (52) installed inside the negative pressure tank body (51); the condensation pipeline (52) is connected to an external condensation water circulation loop.

3. A two-stage temperature-variable deoxidation device based on flue gas waste heat according to claim 2, characterized in that: The condenser (5) further comprises an air pump (10) connected to the negative pressure tank (51) for maintaining a negative pressure environment and a drainage valve (53) for pumping out water and draining water.

4. A two-stage temperature-variable deoxidation device based on flue gas waste heat according to claim 3, characterized in that: The two-stage temperature-variable desulphurization device also comprises a concentrated solution replenishing pump (7) connected to the solution converter (4); the concentrated solution replenishing pump (7) is used to pump concentrated solution into the solution converter (4).

5. A two-stage temperature-variable deoxidation device based on flue gas waste heat according to claim 4, characterized in that: A first circulation pump (8) is provided between the solution converter (4) and the secondary cooling heat exchanger (6), and the first circulation pump (8) is used to continuously pump the low-temperature concentrated solution in the solution converter (4) into the secondary cooling heat exchanger (6).

6. A two-stage temperature-variable deoxidation device based on flue gas waste heat according to claim 5, characterized in that: A second circulation pump (9) is provided between the primary temperature-raising heat exchanger (2) and the spray-type flue gas absorber (3), and the second circulation pump (9) is used to continuously pump the first high-temperature dilute solution at the bottom of the spray-type flue gas absorber (3) into the primary temperature-raising heat exchanger (2).

7. A two-stage temperature-variable deoxidation device based on flue gas waste heat according to claim 6, characterized in that: The two-stage temperature-variable desulphurization device also comprises a first solution molecule adsorber connected to the vacuum pump (10) and a second solution molecule adsorber connected to the drain valve (53).

8. A two-stage temperature-variable deoxidation device based on flue gas waste heat according to claim 7, characterized in that: A first thermometer is installed between the primary temperature-raising heat exchanger (2) and the solution converter (4); and a second thermometer is installed between the secondary temperature-lowering heat exchanger (6) and the spray-type flue gas absorber (3).

9. A two-stage temperature-variable deoxidation device based on flue gas waste heat according to claim 8, characterized in that: The secondary cooling heat exchanger (6) is connected to the external condensed water circulation loop.

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