CN211343076U

CN211343076U - Low-pressure selective catalytic reduction system and control device thereof

Info

Publication number: CN211343076U
Application number: CN201921834935.4U
Authority: CN
Inventors: 梁佳
Original assignee: China Shipbuilding Power Engineering Institute Co Ltd
Current assignee: China Shipbuilding Power Engineering Institute Co Ltd
Priority date: 2019-10-29
Filing date: 2019-10-29
Publication date: 2020-08-25
Anticipated expiration: 2029-10-29

Abstract

The utility model discloses a control device of a low-pressure selective catalytic reduction system and the low-pressure selective catalytic reduction system, wherein the low-pressure selective catalytic reduction system comprises a reactor, an afterburner and a vent valve; the control device comprises a heating module, a regeneration module and a valve control module, wherein the heating module is respectively in communication connection with the regeneration module and the valve control module; the heating module is used for controlling the heating temperature of the afterburner to the reactor; the regeneration module is used for controlling the heating time of the afterburner to the reactor; the valve control module is used for controlling the opening of the ventilation valve according to the working states of the heating module and the regeneration module. The device can heat the reactor to the designated temperature by controlling the afterburner so as to improve the flexibility of the catalyst, and prevent the surface of the catalyst from generating sulfate by controlling certain heating time, so that the reaction efficiency of the low-pressure selective catalytic reduction system is improved, and the discharged waste gas reaches the emission standard.

Description

Low-pressure selective catalytic reduction system and control device thereof

Technical Field

The embodiment of the utility model provides a relate to engine emission technique, especially relate to a low pressure selective catalytic reduction system and controlling means thereof.

Background

In order to reduce the emission of nitrogen oxides, a selective catalytic reduction system is generally required to be arranged to treat the tail gas of a diesel engine, and the current selective catalytic reduction system mainly comprises a low-pressure system and a high-pressure system: the pressure before the supercharger of the marine diesel engine can reach about 4Bar, and the pressure after the supercharger is about 0.03 Bar; thus, a high pressure selective catalytic reduction system is disposed before the supercharger and a low pressure selective catalytic reduction system is disposed after the supercharger.

The traditional low-pressure and low-pressure selective catalytic reduction system is convenient to arrange, but the flexibility of the catalyst is not enough, the catalytic reaction efficiency is low, and sulfate is possibly generated to cause the catalyst to lose effectiveness, so that the engine emission does not reach the standard.

SUMMERY OF THE UTILITY MODEL

Based on this, to above-mentioned technical problem, the utility model provides a low pressure selective catalytic reduction system and controlling means thereof can improve the reaction efficiency of low pressure selective catalytic reduction system to reduce the production of sulphate.

In a first aspect, an embodiment of the present invention provides a control device for a low-pressure selective catalytic reduction system, where the low-pressure selective catalytic reduction system includes a reactor, an afterburner, and a vent valve; the control device comprises a heating module, a regeneration module and a valve control module, wherein the valve control module is respectively in communication connection with the heating module and the regeneration module;

wherein the heating module is used for controlling the heating temperature of the afterburner to the reactor; the regeneration module is used for controlling the heating time of the afterburner on the reactor; the valve control module is used for controlling the opening of the ventilation valve according to the working states of the heating module and the regeneration module.

The control device of the low-pressure selective catalytic reduction system can heat the reactor to the specified temperature by controlling the afterburner so as to improve the flexibility of the catalyst, and prevent the surface of the catalyst from generating sulfate by controlling certain heating time, so that the reaction efficiency of the low-pressure selective catalytic reduction system is improved, and the discharged waste gas reaches the emission standard.

In one embodiment, the vent valve comprises a reactor bypass valve, a reactor inlet valve, a reactor outlet valve, and a reactor throttle valve; under the condition that the heating module works, the valve control module opens the reactor bypass valve and the reactor outlet valve to set opening degrees and closes the reactor inlet valve; the valve control module opens the reactor throttle valve to a set opening degree with the regeneration module operating.

In one embodiment, the low pressure selective catalytic reduction system further includes a fan, and the control device further includes:

the purging module is in communication connection with the valve control module and is used for controlling the fan to blow high-pressure gas into a pipeline of the low-pressure selective catalytic reduction system; the valve control module opens the reactor throttle valve to a fully open state with the purge module operating.

In one embodiment, the ventilation valve further comprises a soot blowing valve, and the control device further comprises a soot blowing module; the soot blowing module is in communication connection with the valve control module and is used for controlling the soot blowing valve to be opened so as to blow soot on the surface of the catalyst in the reactor.

In one embodiment, the low pressure selective catalytic reduction system further comprises an injection device, and the control device further comprises:

and the injection control module is used for controlling the urea amount injected into the reactor by the injection device.

In one embodiment, the control device further comprises a temperature monitoring module, and the temperature control module is respectively connected with the heating module and the injection control module in a communication way; and after the temperature monitoring module monitors that the reactor is heated to a set temperature, the injection control module controls the injection device to inject urea.

In a second aspect, the present invention further provides a low pressure selective catalytic reduction system, including a reactor, an afterburner, a vent valve, and the control device of the low pressure selective catalytic reduction system in the above embodiments, where the afterburner is used to heat the reactor, and the vent valve is communicated with the reactor through a pipeline;

the control device is respectively in communication connection with the ventilation valve and the afterburner, and is used for controlling the heating temperature and the heating time of the afterburner on the reactor and controlling the opening of the ventilation valve.

The low-pressure selective catalytic reduction system can heat the reactor to a specified temperature by controlling the afterburner so as to improve the flexibility of the catalyst, and prevent the surface of the catalyst from generating sulfate by controlling a certain heating time, so that the reaction efficiency of the low-pressure selective catalytic reduction system is improved, and the discharged waste gas reaches the emission standard.

In one embodiment, the low pressure selective catalytic reduction system further comprises:

and the fault handling device is in communication connection with the control device and is used for giving an alarm and/or controlling the low-pressure selective catalytic reduction system to stop when the low-pressure selective catalytic reduction system is abnormal.

and the display device is in communication connection with the control device and is used for displaying the parameter information of the low-pressure selective catalytic reduction system.

Drawings

FIG. 1 is a schematic diagram of a control apparatus for a low pressure selective catalytic reduction system in accordance with one embodiment;

FIG. 2 is a schematic diagram of a control apparatus of a low pressure selective catalytic reduction system in accordance with another embodiment;

FIG. 3 is a block schematic diagram of a low pressure selective catalytic reduction system in one embodiment;

FIG. 4 is a schematic block diagram of a low pressure selective catalytic reduction system in another embodiment;

FIG. 5 is a schematic diagram of a low pressure selective catalytic reduction system in accordance with one embodiment.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.

Fig. 1 is a schematic structural diagram of a control device of a low pressure selective catalytic reduction system in an embodiment, as shown in fig. 1, and in an embodiment, the control device 100 of the low pressure selective catalytic reduction system comprises a reactor, an afterburner and a ventilation valve; the control device 100 comprises a heating module 110, a regeneration module 120 and a valve control module 130, wherein the valve control module 130 is respectively connected with the heating module 110 and the regeneration module 120 in a communication way; wherein, the heating module 110 is used for controlling the heating temperature of the afterburner to the reactor; the regeneration module 120 is used for controlling the heating time of the afterburner on the reactor; the valve control module 130 is configured to control the opening of the vent valve according to the operating states of the heating module 110 and the regeneration module 120.

Specifically, Selective Catalyst Reduction (SCR) technology is used for Nitrogen Oxides (NO) in diesel engine emissions_x) The treatment process of (1) is to spray reducing agent such as urea or liquid ammonia under the action of catalyst to remove NO in the waste gas_xThe technology can be particularly applied to the treatment of diesel engine exhaust gas of ships or automobiles by reducing the waste gas into N2 and H2O. In the low-pressure selective catalytic reduction system, a reactor is used as a space for catalytic reduction reaction, diesel engine exhaust gas enters the reactor through a vent valve, and is reacted with a reducing agent under the action of a catalyst, and then the generated gas is discharged through the vent valve, so that the emission of nitrogen oxides is reduced.

Further, the low temperature of the exhaust gas in the low-pressure SCR system may reduce the efficiency of the catalytic reduction reaction, so that the nitrogen oxides in the exhaust gas may not be sufficiently reduced and may not meet the desired emission standard. Therefore, the afterburner can be controlled by the heating module 110 to heat the reactor, so that the temperature of the reactor reaches the set temperature, and the opening degree of the vent valve of the reactor can be controlled by the valve control module 130 to adjust the speed of the exhaust gas entering and exiting the reactor, thereby improving the speed of the catalytic reduction reaction. The afterburner can be a combustion heating device such as a boiler, the set temperature can be determined according to the reaction temperature of the catalyst and the emission standard, the emission standard can be a Tire II standard or a Tire III standard set by the International Maritime Organization (IMO) aiming at the emission of nitrogen oxides of the diesel engine, and in a preferred embodiment, the temperature of the reactor can be required to be heated to more than 250 ℃.

Since the exhaust gas contains sulfur, there is a possibility that sulfate such as ammonium bisulfate is generated along with a side reaction during the catalytic reduction reaction, and ammonium bisulfate condenses on the surface of the catalyst to block pores, thereby lowering the catalytic efficiency, and there is a possibility that a pipe line in the SCR system is corroded. The regeneration module 120 may heat the reactor to a set temperature and maintain the temperature for a certain period of time, and control the opening of the vent valve of the reactor to maintain the gas flow through the valve control module 130, so that ammonium bisulfate may volatilize from the surface of the catalyst and be discharged out of the reactor, thereby completing the regeneration of the catalyst.

In one embodiment, the vent valve comprises a reactor bypass valve, a reactor inlet valve, a reactor outlet valve, and a reactor throttle valve; in the case where the heating module 110 is operated, the valve control module 130 opens the reactor bypass valve and the reactor outlet valve to set opening degrees, and closes the reactor inlet valve; with the regeneration module 120 operating, the valve control module 130 opens the reactor throttle valve to a set opening.

Specifically, after the preheating function is started, the heating module 110 starts to work, the valve control module 120 opens the reactor bypass valve RBV, closes the reactor inlet valve RSV, opens the reactor outlet valve RTV to a specified opening, starts the afterburner to heat the reactor temperature to a specified temperature, and stops the afterburner and closes the reactor outlet valve RTV until the operator stops preheating or is interrupted by heating other simulation. When the regeneration function is started, the valve control module 120 opens the reactor bypass valve RBV, closes the reactor inlet valve RSV, opens the reactor outlet valve RTV to a specified opening, starts the afterburner, opens the reactor throttle valve CRV to a specified opening, and continues for a certain time until ammonium bisulfate in the reactor is completely removed.

Fig. 2 is a schematic structural diagram of a control device of a low pressure selective catalytic reduction system in another embodiment, as shown in fig. 2, based on the foregoing technical solution, the control device 200 of the low pressure selective catalytic reduction system includes a heating module 210, a regeneration module 220, and a valve control module 230, which may be respectively the same as corresponding structures in the foregoing embodiments, in this embodiment, the low pressure selective catalytic reduction system further includes a fan, and the control device 200 may further include: the purging module 240 is in communication connection with the valve control module 230 and is used for controlling a fan to blow high-pressure gas into a pipeline of the low-pressure selective catalytic reduction system; with the purge module 340 in operation, the valve control module 230 opens the reactor throttle valve to a fully open state.

Specifically, since there is a certain leakage amount between the reactor inlet valve RSV and the reactor outlet valve RTY, the flue gas in the pipeline of the low-pressure SCR system needs to be removed. The purging module 240 can fill the high-pressure gas into the pipeline by periodically starting the fan, so that the flue gas in the pipeline of the low-pressure SCR system is discharged. When the purging module 240 is started, the valve control module 230 opens the reactor bypass valve RBV, closes the reactor inlet valve RSV, opens the reactor outlet valve RTV to a specified opening, opens the reactor throttle valve CRV to a full open stop, and starts the blower of the low-pressure SCR system to purge the pipeline.

In one embodiment, the ventilation valve further comprises a soot blowing valve, and the control device 200 further comprises a soot blowing module 250; the soot blowing module 250 is communicatively connected to the valve control module 230 for controlling the soot blowing valve to be opened for blowing soot on the catalyst surfaces in the reactor. The soot blowing module 250 is used for blowing soot on the surface of the catalyst in the reactor when the flue gas of the diesel engine enters the reactor, so as to prevent the flue gas from blocking and covering the surface of the catalyst. In performing the soot blowing function, the valve control module 230 may open a soot blowing valve on the reactor to blow soot on the catalyst surface. In a preferred embodiment, 12 soot blowing valves are provided on the reactor of the low-pressure SCR system, and the soot blowing process on the catalyst surface in the reactor can be realized by controlling the 12 soot blowing valves.

In one embodiment, the low pressure selective catalytic reduction system further comprises an injection device, and the control device 200 further comprises: and an injection control module 260 for controlling the amount of urea injected into the reactor by the injection device. When urea is selected as the reducing agent for the catalytic reduction reaction, urea liquid needs to be injected into the reactor through an injection device, and the injection control module 260 may determine an injection amount of urea according to the content of nitrogen oxides in the exhaust gas, a required emission standard, and the like, and control the injection device to inject according to the injection amount of urea.

Further, in one embodiment, the control apparatus 200 further includes a temperature monitoring module 270, the temperature control module 270 being in communication with the heating module 210 and the injection control module 260, respectively; the temperature monitoring module 270 may be a temperature sensor disposed on the reactor, and the injection control module 260 controls the injection device to inject urea after the temperature monitoring module 270 monitors that the reactor is heated to a set temperature. Since the catalyst needs to reach a certain temperature to reach an ideal catalytic reduction reaction efficiency to completely react the reductant urea to reach a required emission standard, such as the Tire III standard, the temperature detection module 270 is required to monitor that the temperature of the reactor reaches the temperature, and then the temperature reaching signal is sent to the injection control module 260, and the injection control module 260 controls the injection device to start urea injection to prevent the situation that the catalytic reduction reaction cannot be completely performed due to the injection of urea before the proper reaction condition is reached, so that the exhaust gas after the reaction meets the standard.

In one embodiment, the control device 200 may further include: a manual module 280 communicatively coupled to the valve control module 230 for manually adjusting the opening of the vent valve.

Specifically, the low-pressure SCR system in this embodiment may also be manually controlled by a user or an operator, and the user or the operator may adjust the opening of each vent valve through the manual module 280 according to the actual reaction condition, so that the catalytic reduction reaction is more flexibly controlled. A user or operator may also activate or deactivate other functional modules via the manual module 280 in the event of a failure of the control device 200, thereby achieving redundant control of the low-voltage SCR system.

It can be understood that the embodiment of the present invention provides a control device for a low-pressure selective catalytic reduction system, which has functional modules and beneficial effects for executing corresponding functions. The control device of the low-pressure selective catalytic reduction system in the above embodiment includes units and modules that are divided according to functional logic, but is not limited to the above division as long as the corresponding functions can be realized; in addition, the specific names of the functional modules are only for the convenience of distinguishing from each other, and are not used to limit the protection scope of the present invention.

FIG. 3 is a block schematic diagram of a low pressure selective catalytic reduction system in one embodiment, and as shown in FIG. 3, in one embodiment, a low pressure selective catalytic reduction system 400 includes: the reactor 410, the afterburner 430, the ventilation valve 450 and the control device 200 of the low pressure selective catalytic reduction system in the embodiment, the afterburner 430 is used for heating the reactor 410, and the ventilation valve 450 is communicated with the reactor 410 through a pipeline; the control device 200 is in communication connection with the ventilation valve 450 and the afterburner 430, respectively, and the control device 200 is used for controlling the heating temperature and the heating time of the afterburner 430 to the reactor 410 and controlling the opening degree of the ventilation valve 450.

Specifically, in the low pressure selective catalytic reduction system 500, the reactor 410 may include a closed chamber for providing a suitable reaction environment for the catalytic reduction reaction, and a catalyst may be disposed in the reactor 410, and the catalyst may be a TiO2 substrate, V₂O₅(WO₃)、Fe₂O₃、CuO、CrO_x、MnO_x、MgO、 MoO₃And a metal oxide such as NiO or a mixture thereof acting in combination. The reducing agent may specifically be urea or liquid ammonia. The afterburner 430 can heat the reactor, the afterburner 430 can be a combustion heating device such as a boiler, the heating temperature of the afterburner 430 can be controlled by a heating module of the control device 200, and the heating time of the reactor 410 by the afterburner 430 can be controlled by a regeneration module of the control device 200. The vent valve 450 may be in communication with the chamber of the reactor 410 via a conduit, and the vent valve 450 may specifically include a reactor inlet valve RSV, a reactor outlet valve RTV, and a reactor bypass valve RBV, which may be used to control the rate at which exhaust gas is admitted to and discharged from the reactor. The vent valve 450 may be a solenoid valve, and the opening degree thereof is controlled by an electromagnetic signal sent from a valve control module of the control device 200.

Further, the control device 200 controls the afterburner 430 to heat the temperature of the reactor 410 to a set temperature, so that the rate of the catalytic reduction reaction is increased, the gas circulation is maintained by controlling the opening degree of the vent valve 450, and after heating for a certain time, sulfate such as ammonium bisulfate generated by the reaction volatilizes from the surface of the catalyst and is discharged out of the reactor, so that the regeneration of the catalyst is completed, the activity of the catalyst is ensured, and finally, the exhaust gas discharged by the catalytic reduction reaction can meet the emission standard.

The low-pressure selective catalytic reduction system 500 can heat the reactor to a specified temperature by controlling the afterburner, so that the flexibility of the catalyst is improved, and sulfate is prevented from being generated on the surface of the catalyst by controlling a certain heating time, so that the reaction efficiency of the low-pressure selective catalytic reduction system is improved, and the discharged waste gas reaches the emission standard.

Fig. 4 is a schematic block diagram of a low pressure selective catalytic reduction system in another embodiment, as shown in fig. 4, in one embodiment, based on the above technical solution, the low pressure selective catalytic reduction system 500 includes a reactor 510, an afterburner 530, a ventilation valve 550, and a control device 200 of the low pressure selective catalytic reduction system, which may be respectively the same as the corresponding structures in the above embodiments, and in this embodiment, the low pressure selective catalytic reduction system 500 may further include a fault handling device 570, which is in communication with the control device 200, and is configured to issue an alarm and/or control the low pressure selective catalytic reduction system 500 to be shut down in case of an abnormality of the low pressure selective catalytic reduction system 500.

Specifically, the fault handling device 570 may alarm or stop handling faults occurring while the low-voltage SCR system 500 is under test or in operation. The alarm processing may prompt a user or an operator to check the fault through sound or images, the stopping processing may be manual stopping and automatic stopping, the user or the operator may control the low-voltage SCR system 500 to stop working through the fault processing device 570, and the fault processing device 570 may also automatically stop controlling the low-voltage SCR system 500 to stop working. The stopping process may shut down the low-voltage SCR system 500 as a whole, or may stop only relevant components that have failed, for example, indicating that the main engine sends a stop signal, which may include, for example, an afterburner failure stop, a valve failure stop, a urea injection failure, and the like.

In one embodiment, the low pressure selective catalytic reduction system 500 may further include: and the display device 590 is in communication connection with the control device 200 and is used for displaying parameter information of the low-pressure selective catalytic reduction system 500. The display device 590 may specifically be a display, a projector, or a display screen of a portable device, and the like, and the display device 590 may display an operating state and main parameters of the low-voltage SCR system 500, such as sensor data of temperature, pressure, and pressure difference of each part of the low-voltage SCR system 500, and may also display or record an operating curve of a key value. The display device 590 may also be used to provide an interactive interface, so that a user or an operator may select a start-stop or operation mode of each function, and may also display corresponding fault information or alarm when the low-voltage SCR system 500 has a fault.

Fig. 5 is a schematic structural diagram of a low pressure selective catalytic reduction system in an embodiment, and as shown in fig. 5, in an embodiment, a low pressure selective catalytic reduction system 600 includes a reactor 610, a blower 620, an afterburner 630, and a ventilation valve, which may be respectively the same as the corresponding structures in the above embodiments. The ventilation valves may in particular comprise, among others, a reactor inlet valve RSV, a reactor outlet valve RTV, a reactor bypass valve RB and a reactor throttle valve CRV. The low-pressure SCR system also includes a fan 620, an injection device 660, and a urea storage device 680. The fan 620 is used for realizing gas circulation in the low-pressure SCR system 600, the injection device 660 is connected with the urea storage device 680, and the control device 200 can control the injection device 660 to inject urea in the urea storage device 680 into the reactor 610.

During operation of the low-voltage SCR system 600, a user or an operator may select a Manual mode, an Auto automatic mode, or a Test mode. The test mode is used for testing or debugging the low-voltage SCR system 600, and can judge whether each part is normal in function, and send an alarm or control the low-voltage SCR system 600 to be closed when a fault occurs. The manual mode may be used in the Tire II drain state, in which a user or operator manually adjusts the opening of each valve through the control device 200. The automatic mode may be used for automatic operation of the low-pressure SCR system 600, in which the Tire II discharge state is first entered, the valve control module of the preheating control bank 200 for the reactor 610 sequentially opens the reactor bypass valve RBV, closes the reactor inlet valve RSV, opens the reactor outlet valve RTV to a specified opening, starts the blower 620 to a preset flow rate, and controls the afterburner 630 to heat the reactor to a set temperature, which may be above 250 ℃. The regeneration module of the control device 200 controls the afterburner 630 to heat the reactor 610 for a set time, and opens the reactor throttle valve CRV by a specified opening degree to remove ammonium bisulfate from the surface of the catalyst to complete the regeneration of the catalyst.

After the regeneration of the catalyst is completed, the blower 620 is controlled by the purging module of the control device 200 to blow high-pressure gas into the pipeline, and the valve control module opens the reactor throttle valve CRV to a fully open state, so as to purge the flue gas in the pipeline of the low-pressure SCR system 600. If a user or an operator needs to enter a fire III emission state, a mode switching signal is sent to the control device 200, the low-voltage SCR system 600 enters a PRE fire III emission state, and in the PRE fire III emission state, the low-voltage SCR system 600 needs to perform soot blowing, and a soot blowing module of the control device 200 controls a soot blowing valve on a reactor to perform soot blowing on the surface of a catalyst in the reactor, so that the surface of the catalyst is prevented from being blocked by smoke and covered by the smoke.

After performing soot blowing, the temperature monitoring module of the control device 200 determines whether the temperature of the reactor 610 reaches a set temperature. If the set temperature is not reached, the heating module continues to control the afterburner 630 to heat; if the set temperature is reached, the low-pressure SCR system 600 enters a Tire III emission state. In the Tire III emission state, the injection control module of the control device 200 calculates a demand gate of the reducing agent urea according to the content of the nitrogen oxides in the exhaust gas and the emission standard, controls the injection device 660 to inject the required amount of urea in the urea storage device 680 into the reactor 610, and causes the urea injected into the reactor 610 to perform a catalytic reduction reaction with the nitrogen oxides in the exhaust gas under the catalytic remembering effect to sufficiently reduce NO in the gas discharged from the reactor 610_xAnd (4) in an amount such that it meets the requirements of the Tire III emission standard, completing the operation of the low-pressure SCR system 600.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above embodiments only represent the preferred embodiments of the present invention and the technical principles applied, and the description thereof is specific and detailed, but not construed as limiting the scope of the invention. Numerous obvious variations, adaptations and substitutions will occur to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail with reference to the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the scope of the present invention.

Claims

1. A control apparatus of a low pressure selective catalytic reduction system, wherein the low pressure selective catalytic reduction system comprises a reactor, an afterburner, and a vent valve; the control device comprises a heating module, a regeneration module and a valve control module, wherein the valve control module is respectively in communication connection with the heating module and the regeneration module;

2. The control device of claim 1, wherein the vent valve comprises a reactor bypass valve, a reactor inlet valve, a reactor outlet valve, and a reactor throttle valve; under the condition that the heating module works, the valve control module opens the reactor bypass valve and the reactor outlet valve to set opening degrees and closes the reactor inlet valve; the valve control module opens the reactor throttle valve to a set opening degree with the regeneration module operating.

3. The control device of claim 2, wherein the low pressure selective catalytic reduction system further comprises a fan, the control device further comprising:

4. The control device of claim 2, wherein the vent valve further comprises a soot blowing valve, the control device further comprising a soot blowing module; the soot blowing module is in communication connection with the valve control module and is used for controlling the soot blowing valve to be opened so as to blow soot on the surface of the catalyst in the reactor.

5. The control apparatus of claim 1, wherein the low pressure selective catalytic reduction system further comprises an injection device, the control apparatus further comprising:

6. The control device of claim 5, further comprising a temperature monitoring module, the temperature control module being in communication with the heating module and the injection control module, respectively; and after the temperature monitoring module monitors that the reactor is heated to a set temperature, the injection control module controls the injection device to inject urea.

7. The control device according to claim 1, characterized by further comprising:

and the manual module is in communication connection with the valve control module and is used for manually adjusting the opening degree of the ventilation valve.

8. A low pressure selective catalytic reduction system comprising a reactor, an afterburner for heating the reactor, a vent valve in communication with the reactor through a conduit, and a control device of the low pressure selective catalytic reduction system of any one of claims 1 to 7;

9. The low pressure selective catalytic reduction system of claim 7, further comprising:

10. The low pressure selective catalytic reduction system of claim 7, further comprising: