A desulfurization system and a control method for a desulfurization system

Abstract

The present application discloses a desulfurization system and a control method for the desulfurization system, wherein the desulfurization system comprises: an oxidation air unit, wherein the oxidation air unit comprises at least two oxidation air units with different powers; an absorption tower, wherein the absorption tower comprises a reaction chamber, wherein the tail gas discharge port is connected to the interior of the reaction chamber through a first pipeline, and the air outlet of each oxidation air unit of the at least two oxidation air units with different powers is connected to the interior of the reaction chamber through a second pipeline; and a controller, wherein the coal-fired unit and the oxidation air unit are electrically connected to the controller respectively; wherein the controller is used to control the start-up of at least one oxidation air unit of the at least two oxidation air units with different powers based on the actual load rate of the coal-fired unit, so that the output power of the oxidation air unit matches the actual load rate of the coal-fired unit. The solution provided in the embodiment of the present application can solve the problem of power consumption waste in the existing desulfurization system.

Description

Technical Field

[0001] The present application relates to the field of tail gas treatment of coal-fired units, and in particular to a desulfurization system and a control method for the desulfurization system. Background Art

[0002] In the prior art, the sulfur in the tail gas of thermal power generation equipment is mainly treated by the wet desulfurization principle, which is to react SO2 in the flue gas with limestone to obtain calcium sulfite, and then oxidize and crystallize the calcium sulfite to form gypsum, thereby solidifying the pollutants and utilizing resources. In order to ensure that the calcium sulfite can be fully oxidized in the process, the prior art usually uses an oxidation fan to introduce excessive air into the slurry, however, this will lead to low operating efficiency of the oxidation fan, which will lead to the problem of wasteful power consumption. Summary of the invention

[0003] The present application provides a desulfurization system and a control method for the desulfurization system, which can solve the problem of power consumption waste in the existing desulfurization system.

[0004] In order to solve the above technical problems, this application is implemented as follows:

[0005] In a first aspect, an embodiment of the present application provides a desulfurization system, which is applied to a coal-fired unit, wherein the coal-fired unit includes a tail gas discharge port, and the desulfurization system includes:

[0006] An oxidation fan unit, the oxidation fan unit comprising at least two oxidation fans with different powers;

[0007] An absorption tower, the absorption tower comprising a reaction chamber, the tail gas discharge port being connected to the interior of the reaction chamber through a first pipeline, and the air outlet of each of the at least two oxidation fans with different powers being connected to the interior of the reaction chamber through a second pipeline;

[0008] A controller, the coal-fired unit and the oxidation air unit are electrically connected to the controller respectively;

[0009] Wherein, the controller is used to control the start-up of at least one of the at least two oxidation fans with different powers based on the actual load rate of the coal-fired unit, so that the output power of the oxidation fan unit matches the actual load rate of the coal-fired unit.

[0010] Optionally, the desulfurization system further includes at least two second pipelines corresponding to the at least two oxidation blowers with different powers, and the air outlet of each oxidation blower is connected to the reaction chamber through the corresponding second pipeline;

[0011] The power of the target fan is proportional to the square of the inner diameter of the target pipeline, the target fan is any oxidation fan in the oxidation fan group, and the target pipeline is the second pipeline corresponding to the target fan among the at least two second pipelines.

[0012] Optionally, the target pipeline includes an exhaust section located in the reaction chamber, and one end of the target pipeline located in the reaction chamber is closed, and a side wall of the exhaust section is provided with a plurality of gas injection holes.

[0013] Optionally, the absorption tower further comprises an agitator, and the agitator is disposed inside the reaction chamber.

[0014] Optionally, the desulfurization system further comprises a slurry supply device for producing desulfurization slurry, the side wall of the reaction chamber is further provided with a slurry inlet, and the discharge port of the slurry supply device is connected to the slurry inlet.

[0015] Optionally, a first one-way valve is provided in the first pipeline, and a second one-way valve is provided in the second pipeline.

[0016] Optionally, the desulfurization system further includes a water inlet pipe and a sprayer, wherein the sprayer is arranged inside the absorption tower and located above the reaction chamber, and the water inlet pipe is connected to the water inlet of the sprayer.

[0017] Optionally, the desulfurization system further includes a demister, which is disposed inside the absorption tower and is located above the sprayer.

[0018] In a second aspect, an embodiment of the present application further provides a control method for a desulfurization system, which is applied to a controller, wherein the controller is the controller of the desulfurization system described in the first aspect above, and the method comprises:

[0019] Obtain the actual load rate of the coal-fired units;

[0020] At least one of at least two oxidation fans with different powers is controlled to start according to the actual load rate, so that the output power of the oxidation fan unit matches the actual load rate of the coal-fired unit.

[0021] Optionally, the method of controlling at least one oxidation fan of at least two oxidation fans with different powers to start according to the actual load rate comprises:

[0022] Determining the target wind turbine power according to the actual load rate;

[0023] Determining at least one target fan among the at least two oxidation fans with different powers, wherein a total power of the at least one target fan matches the power of the target fan;

[0024] Control the start-up of each target fan.

[0025] In an embodiment of the present application, a controller controls the start-up of at least one of at least two oxidation fans with different powers based on the actual load rate of the coal-fired unit, so that the output power of the oxidation fan unit matches the actual load rate of the coal-fired unit. In this way, the problem of power consumption waste in the desulfurization system can be effectively alleviated. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural schematic diagram of a desulfurization system provided in an embodiment of the present application;

[0027] Figure 2 is a schematic diagram of the connection relationship between the oxidation air unit and the absorption tower in the embodiment of the present application;

[0028] Figure 3 It is a flow chart of a control method of a desulfurization system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0030] The terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are generally of one type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0031] See also Figure 1A desulfurization system provided in an embodiment of the present application is applied to a coal-fired unit 100, wherein the coal-fired unit 100 includes a tail gas discharge port, and the desulfurization system includes: an oxidation air unit, wherein the oxidation air unit includes at least two oxidation air fans 200 with different powers; an absorption tower 300, wherein the absorption tower 300 includes a reaction chamber 301, wherein the tail gas discharge port is connected to the interior of the reaction chamber 301 through a first pipeline 400, and the air outlet of each oxidation air fan 200 of the at least two oxidation air fans 200 with different powers is connected to the interior of the reaction chamber 301 through a second pipeline 500; a controller, wherein the coal-fired unit 100 and the oxidation air unit are electrically connected to the controller respectively; wherein the controller is used to control the start-up of at least one oxidation air fan 200 of the at least two oxidation air fans 200 with different powers based on the actual load rate of the coal-fired unit 100, so that the output power of the oxidation air unit matches the actual load rate of the coal-fired unit 100.

[0032] The oxidation fan group includes at least two oxidation fans 200 with different powers, where the power refers to the rated power of the oxidation fans 200. The controller may be an industrial computer, for example, a PLC.

[0033] Please see further Figure 1 The reaction chamber 301 may be formed at the bottom of the absorption tower 300, that is, the reaction chamber 301 may be a chamber with an upper opening formed by the bottom plate of the absorption tower 300 and the side wall of the absorption tower 300. The side wall of the reaction chamber 301 may be provided with an exhaust gas inlet 302 and an air inlet 303, the first pipeline 400 may be connected to the interior of the reaction chamber 301 through the exhaust gas inlet 302, and the second pipeline 500 may extend into the interior of the reaction chamber 301 through the air inlet 303. In addition, an exhaust port 307 is formed at the top of the absorption tower 300, and after the exhaust gas is purified in the absorption tower 300, the purified gas may be discharged to the outside through the exhaust port 307.

[0034] Since the actual load of the coal-fired unit 100 may be different in different time periods, the amount of tail gas generated by the coal-fired unit 100 in different time periods is also different accordingly. Accordingly, the air consumed to process different amounts of tail gas is also different. Based on this, in an embodiment of the present application, at least one of at least two oxidation fans 200 with different powers is controlled to start based on the actual load rate of the coal-fired unit 100, so that the output power of the oxidation fan unit matches the actual load rate of the coal-fired unit 100, that is, the amount of air provided by the oxidation fan unit to the absorption tower 300 matches the amount of tail gas generated by the coal-fired unit 100, so that the problem of power consumption waste in the oxidation fan unit can be effectively alleviated.

[0035] The oxidation fan unit includes several output powers, wherein starting different oxidation fans 200, or starting different oxidation fan combinations, can obtain different output powers of the oxidation fan unit. Therefore, a corresponding relationship between the output power of the oxidation fan unit and the actual load rate of the coal-fired unit 100 can be pre-established, so as to realize the control of starting at least one oxidation fan 200 of at least two oxidation fans 200 with different powers based on the actual load rate of the coal-fired unit 100.

[0036] Specifically, by making the rated power of each oxidation fan 200 in the above oxidation fan group different, different oxidation fan combinations can correspond to different output powers of the oxidation fan group, thereby effectively increasing the output power adjustment range of the oxidation fan group. In one embodiment of the present application, when the oxidation fan group includes N balcony fans with different powers, theoretically, the oxidation fan group has output power. For example, see Figure 2 , the oxidation wind unit includes a first wind unit 201, a second wind unit 202 and a third wind unit 203, wherein the rated power of the first wind unit 201 is 3000 cubic meters per hour, the rated power of the second wind unit 202 is 4000 cubic meters per hour, and the rated power of the third wind unit 203 is 5000 cubic meters per hour, then the output power of the oxidation wind unit may include the following 6 situations: 3000 cubic meters per hour, 4000 cubic meters per hour, 5000 cubic meters per hour, (3000+4000) cubic meters per hour, (3000+5000) cubic meters per hour, (4000+5000) cubic meters per hour, (3000+4000+5000) cubic meters per hour. In this case, the corresponding relationship between the output power of the above oxidation wind unit and the actual load rate of the coal-fired unit 100 may be:

[0037] When the actual load rate of the coal-fired unit 100 is 90%-100%, the output power of the oxidation wind unit is (3000+4000+5000) cubic meters per hour. At this time, three fans are turned on;

[0038] When the actual load rate of the coal-fired unit 100 is 80%-90%, the output power of the oxidation fan unit is (4000+5000) cubic meters per hour. At this time, the second fan 202 and the third fan 203 are turned on;

[0039] When the actual load rate of the coal-fired unit 100 is 70%-80%, the output power of the oxidation wind unit is (3000+5000) cubic meters per hour. At this time, the first fan 201 and the third fan 203 are turned on;

[0040] When the actual load rate of the coal-fired unit 100 is 60%-70%, the output power of the oxidation fan unit is (3000+4000) cubic meters per hour. At this time, the first fan 201 and the second fan 202 are turned on;

[0041] When the actual load rate of the coal-fired unit 100 is 50%-60%, the output power of the oxidation wind unit is 5000 cubic meters per hour. At this time, the third wind fan 203 is turned on;

[0042] When the actual load rate of the coal-fired unit 100 is 40%-50%, the output power of the oxidation wind unit is 4000 cubic meters per hour. At this time, the second wind fan 202 is turned on;

[0043] When the actual load rate of the coal-fired unit 100 is 30%-40%, the output power of the oxidation wind unit is 3000 cubic meters per hour. At this time, the first wind fan 201 is turned on.

[0044] The oxidation blower 200 in the startup state can operate at rated power, so that the air input into the reaction chamber 301 by the oxidation blower unit can have a higher flow rate, thereby ensuring that the air entering the reaction chamber 301 can be fully diffused.

[0045] It is understandable that the reaction chamber 301 is provided with a desulfurization slurry, wherein the desulfurization slurry may be a limestone slurry, so that when the tail gas of the coal-fired unit 100 enters the reaction chamber 301, the SO2 in the tail gas may react with the limestone to obtain calcium sulfite. At the same time, the air provided by the oxidation blower unit to the reaction chamber 301 may further oxidize the calcium sulfite to obtain gypsum, thereby achieving purification of the SO2 in the tail gas.

[0046] In this embodiment, the controller controls the start-up of at least one of at least two oxidation fans 200 with different powers based on the actual load rate of the coal-fired unit 100, so that the output power of the oxidation fan unit matches the actual load rate of the coal-fired unit 100. In this way, the problem of power consumption waste in the desulfurization system can be effectively alleviated.

[0047] Optionally, the desulfurization system further includes at least two second pipelines 500 corresponding to the at least two oxidation fans 200 with different powers, and the air outlet of each oxidation fan 200 is connected to the reaction chamber 301 through the corresponding second pipeline 500;

[0048] The power of the target fan is proportional to the square of the inner diameter of the target pipeline, the target fan is any oxidation fan 200 in the oxidation fan group, and the target pipeline is the second pipeline 500 corresponding to the target fan among the at least two second pipelines 500.

[0049] Specifically, for an oxidation blower 200 with a larger rated power, a second pipeline 500 with a larger inner diameter can be used to connect to the first air inlet. In this way, the flow rate of air in each second pipeline 500 can be ensured to be relatively stable, thereby improving the stability of the flow rate of air provided by the oxidation blower group to the reaction chamber 301.

[0050] Optionally, the target pipeline includes an exhaust section 501 located in the reaction chamber 301 , and one end of the target pipeline located in the reaction chamber 301 is closed, and a side wall of the exhaust section 501 is provided with a plurality of gas injection holes 502 .

[0051] Specifically, the exhaust section 501 may be the portion of the target pipeline extending into the interior of the reaction chamber 301. Since the target pipeline may be any second pipeline 500 of the at least two second pipelines 500, that is, each second pipeline 500 includes an exhaust section 501 located inside the reaction chamber 301. It is understandable that the directions of the multiple spray holes opened in the exhaust section 501 may be different, so that the oxidation wind entering the second pipeline 500 may be sprayed toward different positions of the reverse chamber through the spray holes 502 of the exhaust section 501 with different directions, thereby further improving the oxidation effect on the slurry inside the reaction chamber 301.

[0052] Optionally, the desulfurization system further includes a slurry supply device for producing desulfurization slurry, and the side wall of the reaction chamber 301 is further provided with a slurry inlet, and the discharge port of the slurry supply device can be connected to the slurry inlet through a third pipeline, so that the slurry supply device continuously provides limestone slurry into the reaction chamber 301. In addition, the absorption tower 300 also includes a discharge port, and the gypsum slurry obtained after oxidation can flow into the downstream equipment for processing through the discharge port.

[0053] Optionally, the absorption tower 300 further includes an agitator, which is disposed inside the reaction chamber 301 .

[0054] In this embodiment, by arranging a stirrer in the reaction chamber 301, the tail gas, air and limestone slurry can be fully contacted under the stirring action of the stirrer, thereby further improving the sufficiency of the reaction.

[0055] Optionally, a first one-way valve is disposed in the first pipeline 400 , and a second one-way valve is disposed in the second pipeline 500 .

[0056] In this embodiment, by setting a first one-way valve in the first pipeline 400, the material in the reaction chamber 301 can be effectively prevented from flowing to the coal-fired unit 100 through the first pipeline 400. Correspondingly, by setting a second one-way valve in the second pipeline 500, the material in the reaction chamber 301 can be effectively prevented from flowing to the oxidation blower 200 through the second pipeline 500.

[0057] Optionally, the desulfurization system further includes a water inlet pipe 304 and a sprayer 305 , wherein the sprayer 305 is disposed inside the absorption tower 300 and located above the reaction chamber 301 , and the water inlet pipe 304 is connected to a water inlet of the sprayer 305 .

[0058] In this embodiment, a sprayer 305 is provided in the absorption tower 300 , so that the sprayer 305 can spray industrial water into the absorption tower 300 , and the industrial water sprayed by the sprayer 305 can further absorb harmful substances in the exhaust gas flowing from the reaction chamber 301 to the top.

[0059] Optionally, the desulfurization system further includes a demister 306 , which is disposed inside the absorption tower 300 and is located above the sprayer 305 .

[0060] Specifically, since the absorption tower 300 is prone to produce "fog" of 10-60 microns during operation, the "fog" contains not only moisture, but also sulfuric acid, sulfate, sulfur dioxide, etc. Based on this, in the embodiment of the present application, a demister 306 is set in the absorption tower 300, so that when the gas containing mist passes through the demister 306 at a certain speed, it will collide with the internal structure of the demister 306 and adhere to its surface. The mist on the surface of the internal structure of the demister 306 will gradually gather through diffusion and gravity, and when the weight reaches a certain level, it will be separated from the internal structure of the demister 306. Thereby, the safety of the gas discharged from the absorption tower 300 can be further improved.

[0061] See also Figure 3 The present application also provides a method for controlling a desulfurization system, which is applied to a controller. The controller is the controller in the desulfurization system described in the above embodiment. The method includes:

[0062] Step 301, obtaining the actual load rate of the coal-fired unit 100;

[0063] Step 302 : Control at least one oxidation blower 200 of at least two oxidation blowers 200 with different powers to start according to the actual load rate, so that the output power of the oxidation blower unit matches the actual load rate of the coal-fired unit 100 .

[0064] Optionally, the method of controlling at least one oxidation fan 200 of at least two oxidation fans 200 with different powers to start according to the actual load rate includes:

[0065] Determining the target wind turbine power according to the actual load rate;

[0066] Determining at least one target fan among the at least two oxidation fans 200 with different powers, wherein a total power of the at least one target fan matches the target fan power;

[0067] Control the start-up of each target fan.

[0068] The target fan may be any oxidation fan 200 in the oxidation fan group.

[0069] This embodiment is a method corresponding to the desulfurization system provided in the above embodiment. The specific implementation process can be found in the above embodiment. To avoid repetition, it will not be described again here.

[0070] It should be noted that, in this article, the terms "comprise", "include" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise one..." do not exclude the presence of other identical elements in the process, method, article or device including the element. In addition, it should be pointed out that the scope of the methods and devices in the embodiments of the present application is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in reverse order according to the functions involved, for example, the described method may be performed in an order different from that described, and various steps may also be added, omitted, or combined. In addition, the features described with reference to certain examples may be combined in other examples.

[0071] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can also make many forms without departing from the purpose of the present application and the scope of protection of the claims, all of which are within the protection of the present application.

Claims

1. A desulfurization system, applied to a coal-fired unit, wherein the coal-fired unit comprises a tail gas discharge port, characterized in that: The desulfurization system comprises: An oxidation fan unit, the oxidation fan unit comprising at least two oxidation fans with different powers; An absorption tower, the absorption tower comprising a reaction chamber, the tail gas discharge port being connected to the interior of the reaction chamber through a first pipeline, and the air outlet of each of the at least two oxidation fans with different powers being connected to the interior of the reaction chamber through a second pipeline; A controller, the coal-fired unit and the oxidation air unit are electrically connected to the controller respectively; The controller is used to control the start-up of at least one oxidation fan of the at least two oxidation fans with different powers based on the actual load rate of the coal-fired unit, so that the output power of the oxidation fan unit matches the actual load rate of the coal-fired unit, wherein the started oxidation fan operates at rated power; The desulfurization system further includes at least two second pipelines corresponding to the at least two oxidation blowers with different powers, and the air outlet of each oxidation blower is connected to the reaction chamber through the corresponding second pipeline; The power of the target fan is proportional to the square of the inner diameter of the target pipeline, the target fan is any one of the oxidation fans in the oxidation fan group, and the target pipeline is the second pipeline corresponding to the target fan among the at least two second pipelines; The desulfurization system further includes a slurry supply device for generating desulfurization slurry. The side wall of the reaction chamber is further provided with a slurry inlet, and the discharge port of the slurry supply device is connected to the slurry inlet.

2. The desulfurization system according to claim 1, characterized in that: The target pipeline comprises an exhaust section located in the reaction chamber, and one end of the target pipeline located in the reaction chamber is closed, and a side wall of the exhaust section is provided with a plurality of injection holes.

3. The desulfurization system according to claim 1, characterized in that: The absorption tower further comprises a stirrer, and the stirrer is arranged inside the reaction chamber.

4. The desulfurization system according to claim 1, characterized in that: A first one-way valve is disposed in the first pipeline, and a second one-way valve is disposed in the second pipeline.

5. The desulfurization system according to claim 1, characterized in that: The desulfurization system further comprises a water inlet pipe and a sprayer. The sprayer is arranged inside the absorption tower and above the reaction chamber. The water inlet pipe is connected to the water inlet of the sprayer.

6. The desulfurization system according to claim 5, characterized in that: The desulfurization system further comprises a demister, which is arranged inside the absorption tower and above the sprayer.

7. A control method for a desulfurization system, applied to a controller, wherein the controller is the controller of the desulfurization system according to any one of claims 1 to 6, characterized in that: The method comprises: Obtain the actual load rate of the coal-fired units; At least one of at least two oxidation fans with different powers is controlled to start according to the actual load rate, so that the output power of the oxidation fan unit matches the actual load rate of the coal-fired unit.

8. The method according to claim 7, characterized in that The method of controlling at least one oxidation fan of at least two oxidation fans with different powers to start according to the actual load rate comprises: Determining the target wind turbine power according to the actual load rate; Determining at least one target fan among the at least two oxidation fans with different powers, wherein a total power of the at least one target fan matches the power of the target fan; Control the start-up of each target fan.

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