Coupling sintering CO removal device and operation control method thereof

Abstract

The invention belongs to the technical field of flue gas treatment and the field of environmental protection, and particularly relates to a coupled sintering CO removal device and an operation control method thereof. The coupled sintering CO removal device comprises a desulfurization device, a dust remover, a flue gas heater, a CO reaction part and an SCR (Selective Catalytic Reduction) reactor. According to the method, the coupled sintering CO removal device is cooperatively controlled in the starting stage, the operation stage and the shutdown stage, so that the CO catalyst is prevented from being poisoned and inactivated, and the service life of the CO catalyst is effectively prolonged.

Description

Technical Field

[0001] The present invention belongs to the technical fields of flue gas treatment and environmental protection, and particularly relates to a coupled sintering CO removal device and an operation control method thereof. Background Technique

[0002] The sintering machine is a major emitter of CO in iron and steel enterprises, and it is imperative to reduce CO emissions from the sintering machine. At present, the main method for reducing CO emissions from the sintering machine is the catalytic oxidation method, which uses a CO catalyst to oxidize CO in the sintering flue gas into CO2.

[0003] According to the different positions of the catalyst arrangement, the catalytic oxidation method is mainly divided into two processes. One is a coupled process with an independent CO reactor arranged before the denitrification ammonia injection, and the other is an embedded process that directly puts the CO catalyst into the SCR reactor. The CO catalyst has high requirements for the flue gas environment and is prone to poisoning and inactivation. The coupled CO removal process has an independent reactor and is equipped with a bypass and a regulating air damper, which can effectively control the heat release of CO oxidation, avoid SCR overheating, and the CO catalyst is arranged upstream of the denitrification ammonia injection, and there is no ammonia in the flue gas. Compared with the embedded process, the coupled CO removal process can provide a better flue gas environment for the CO catalyst.

[0004] The existing operation control methods for CO removal devices mainly focus on the control of the operating temperature, to avoid sulfur poisoning of the CO catalyst due to too low an operating temperature and a decrease in SCR denitration efficiency, and at the same time avoid GGH jamming due to too high an operating temperature, which affects the stable operation of the system. For example, CN112403258A discloses a system and method for flue gas de-carbon monoxide and denitration. This system mainly uses the heat released during the conversion of carbon monoxide into carbon dioxide to raise the temperature of the flue gas for denitration treatment, which not only saves the use of fuel but also avoids the problem that the CO catalyst is prone to deactivation when encountering sulfur oxides at low temperatures. CN221964936U discloses a carbon monoxide removal device and a sintered SCR system. When the carbon monoxide removal device operates, the carbon monoxide reaction gas path removes carbon monoxide in the flue gas. When the carbon monoxide catalyst needs to be replaced, the carbon monoxide reaction gas path can be closed, and the flue gas is then transported to the SCR reaction section through the flue gas bypass. This not only avoids the influence of ammonia on the carbon monoxide catalyst but also ensures that the denitration system and the sintering machine can operate normally synchronously. Both CN112403258A and CN221964936U adopt a coupled CO removal process, using a bypass and an adjustable baffle to control the node where the flue gas enters the CO removal device, to avoid sulfur poisoning of the CO catalyst due to too low an operating temperature and a decrease in SCR denitration efficiency, and at the same time avoid GGH jamming due to too high an operating temperature, which affects the stable operation of the system. However, it has been found in the practical process that even if the operating temperature is very stably controlled, the CO catalyst still exhibits significant poisoning and deactivation problems and cannot operate stably for a long time, resulting in unexpected shutdown and maintenance during the operation of the equipment, etc. Summary of the Invention

[0005] The purpose of the present invention is to overcome the problem that there is still significant poisoning and deactivation of the CO catalyst when the existing CO removal device is controlled by operating temperature, and to provide a new coupled sintered CO removal device and its operation control method.

[0006] The coupled sintered CO removal device provided by the present invention includes:

[0007] A desulfurization device for removing SO2 from the flue gas;

[0008] A dust collector connected downstream of the desulfurization device along the flue gas flow direction for dust removal of the flue gas;

[0009] A flue gas heater connected downstream of the dust collector along the flue gas flow direction for heating the flue gas; an SO2 concentration detector, a dust concentration detector, a humidity detector, and an HCl concentration detector are provided on the connecting pipeline between the flue gas heater and the dust collector;

[0010] The CO reaction section is connected downstream of the flue gas heater along the flue gas flow direction. The CO reaction section includes a CO removal gas path and a CO bypass that are connected in parallel. A CO reactor is provided on the CO removal gas path. The opening and closing of the CO removal gas path are controlled by a CO inlet air damper provided at the inlet end of the CO reactor and a CO outlet air damper provided at the outlet end of the CO reactor. The opening and closing of the CO bypass are controlled by a CO bypass air damper provided on the CO bypass;

[0011] The SCR reactor is connected downstream of the CO reaction section along the flue gas flow direction and is used for denitrifying the flue gas.

[0012] In a preferred embodiment, the coupled sintering CO removal device further includes a desulfurization recycle flue for recycling the flue gas led out from the SCR reactor to the desulfurization device, and a desulfurization recycle air damper is provided on the desulfurization recycle flue.

[0013] In a preferred embodiment, the coupled sintering CO removal device further includes a flue gas heat exchanger for heat-exchanging the flue gas led out from the dust collector and the SCR reactor.

[0014] In a preferred embodiment, the coupled sintering CO removal device further includes a sintering machine that is connected upstream of the desulfurization device along the flue gas flow direction and is used for providing sintering flue gas.

[0015] The operation control method of the coupled sintering CO removal device provided by the present invention includes sequentially introducing the flue gas to be CO-removed into the desulfurization device, the dust collector, and the flue gas heater to remove SO2, dust, and heat. The obtained hot flue gas is introduced into the SCR reactor for denitrification after removing CO through the CO reactor on the CO removal gas path or directly introduced into the SCR reactor for denitrification through the CO bypass. The following methods are used for control during startup, operation, and shutdown:

[0016] S1. Startup control: After startup, the CO bypass and optionally the desulfurization recycle flue are opened to establish an internal flue gas circulation, the CO removal gas path is closed, and the flue gas heating device is started to preheat the SCR reactor; the humidity of the flue gas at the outlet of the dust collector is detected by a humidity detector. After the humidity no longer changes, the CO removal gas path is opened, the CO bypass is closed, and the low-humidity high-temperature flue gas is introduced into the CO reactor to preheat and raise the temperature of the CO reactor; after the CO reactor reaches the designed operating temperature, the CO bypass is opened, the CO removal gas path is closed, so as to isolate the CO reactor from the flue gas;

[0017] S2. Operation process control: Detect the concentrations of SO2, dust, H2O and HCl through a SO2 concentration detector, a dust concentration detector, a humidity detector and an HCl concentration detector; when the concentrations of SO2, dust and H2O in the flue gas at the outlet of the dust collector exceed the threshold and the duration exceeds the threshold, then conduct the CO bypass, close the CO removal gas path, isolate the CO reactor from the flue gas, and wait until the concentrations of SO2, dust and H2O in the flue gas at the outlet of the dust collector drop below the threshold and the duration exceeds the threshold, then conduct the CO removal gas path again, close the CO bypass, and introduce the flue gas into the CO reactor again; when the concentration of HCl in the flue gas at the outlet of the dust collector exceeds the threshold and the duration exceeds the threshold, then put HCl removal agent into the desulfurization device;

[0018] S3. Shutdown process control: During shutdown, conduct the CO bypass, close the CO removal gas path, and isolate the CO reactor from the flue gas.

[0019] In a preferred embodiment, the operation control method of the coupled sintering CO removal device further includes that in the initial stage of starting the sintering machine, if the concentrations of SO2, dust, H2O and HCl in the flue gas at the outlet of the dust collector are already lower than the threshold and the duration exceeds the threshold, then put CO adsorbent into the desulfurization device to adsorb and remove the trace pollutant components in the flue gas in the initial stage of startup.

[0020] In a preferred embodiment, the operation control method of the coupled sintering CO removal device further includes that during startup, the temperature for preheating and raising the temperature of the SCR reactor is 100 - 150 °C, and the duration at the preheating temperature is 1 h - 2 h.

[0021] In a preferred embodiment, the operation control method of the coupled sintering CO removal device further includes satisfying the following condition A and / or condition B during the operation process:

[0022] A: When the operating temperature t of the desulfurization device s is higher than the set maximum temperature and the duration exceeds the threshold T 脱硫 then put CO adsorbent into the desulfurization device;

[0023] B: When the indexes of the flue gas at the outlet of the dust collector meet the following conditions A` - C`, then conduct the CO bypass, close the CO removal gas path, and isolate the CO reactor from the flue gas, otherwise conduct the CO removal gas path, close the CO bypass, and introduce the flue gas into the CO reactor;

[0024] A`: The concentration of SO2 in the flue gas at the outlet of the dust collector is 35 mg / Nm 3 or more and the duration exceeds the threshold T SO2 ;

[0025] B`: The dust concentration in the flue gas at the outlet of the dust collector is 10 mg / Nm3 Above and the duration exceeds the threshold T 粉层 ;

[0026] C': The humidity of the flue gas at the dust collector outlet is above 20% and the duration exceeds the threshold value T 湿度 .

[0027] In a preferred embodiment, T 脱硫 1.5~3h; T SO2 0.5~2h; T 粉尘 1 to 2 hours; T 湿度 1.5 to 3 hours.

[0028] In a preferred embodiment, when the CO removal gas path is connected and the CO bypass is closed to the CO removal gas path is closed and the CO bypass is connected, the CO bypass damper is opened in sequence, the CO inlet damper is closed, and the CO outlet damper is closed; when the CO removal gas path is closed and the CO bypass is connected to the CO removal gas path is connected and the CO bypass is closed, the CO outlet damper is opened in sequence, the CO inlet damper is opened, and the CO bypass damper is closed.

[0029] As described above, for the coupled CO removal process, the prior art basically avoids the poisoning and inactivation of the CO catalyst by controlling the operating temperature. However, it is found in the practical process that even if the operating temperature is stably controlled, the significant inactivation problem of the CO catalyst still occurs. Based on this, the inventors of the present invention have found through in-depth and extensive research that in the coupled CO removal process, in addition to the temperature factor, the factors that dominate the influence on the activity of the CO catalyst in the startup stage, the operation stage, and the shutdown stage are different. In the startup stage and the shutdown stage, water vapor has a significant impact on the activity of the CO catalyst. The water vapor in the flue gas is very likely to condense on the surface of the CO catalyst in the startup stage and the shutdown stage, resulting in the poisoning and inactivation of the CO catalyst. In the operation stage, the concentrations of SO2, dust, H2O, HCl, and trace pollutants in the flue gas jointly affect the activity of the CO catalyst. If the concentrations of SO2, dust, H2O, HCl, and trace pollutants in the flue gas are too high, it will cause phenomena such as poisoning, blockage, and carbon deposition of the active sites of the CO catalyst, which will seriously affect the activity of the CO catalyst. In the startup stage of the present invention, the hot flue gas is first passed through the CO bypass to preheat the SCR reactor. After the SCR reactor is preheated and the humidity in the flue gas is basically unchanged, the hot flue gas is then passed through the CO removal gas path to preheat and raise the temperature of the CO reactor. After the CO reactor reaches the designed operating temperature, the CO removal gas path is closed, and the CO bypass is conducted to avoid the condensation of water vapor in the flue gas on the surface of the CO catalyst, resulting in the poisoning and inactivation of the CO catalyst. In the operation stage, under abnormal conditions where the concentrations of SO2, dust, and H2O in the flue gas are too high, the CO removal gas path is closed, and the CO reactor is cut out and changed to the bypass operation state. When the concentration of HCl in the flue gas is too high, the HCl removal agent is put in, and optionally, when the concentration of trace pollutants is too high, the CO special adsorbent is put in to avoid the influence of excessive SO2, dust, H2O, HCl, and other trace pollutants on the service life of the CO catalyst. In the shutdown stage, the CO removal gas path is closed, the flue gas is changed to pass through the CO bypass, and the CO reactor is isolated from the flue gas. The CO reactor relies on the heat dissipation of the outer shell to cool down slowly. During the cooling process, the flue gas condensate mainly occurs on the outer shell wall panel and will not accumulate on the surface of the CO catalyst, effectively protecting the CO catalyst from the influence of condensate. In summary, the present invention avoids the poisoning and inactivation of the CO catalyst through the coordinated control in the startup stage, the operation stage, and the shutdown stage, thereby effectively extending the service life of the CO catalyst. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The present invention will be described in detail by combining with the drawings, which form a part of the specification and are used to explain the present invention together with the following specific embodiments, but do not constitute a limitation to the present invention. The drawings are only exemplary diagrams of the present invention and are not necessarily drawn to scale. In the drawings, the same reference numerals always represent the same or similar components. Among them:

[0031] Figure 1This is a schematic structural diagram of the coupled sintering CO removal device provided by the present invention.

[0032] Description of reference numerals: 1 - sintering machine; 2 - desulfurization device; 3 - dust collector; 4 - flue at the outlet of the dust collector; 5 - flue gas heating device; 6 - CO removal gas path; 7 - CO inlet air damper; 8 - CO reactor; 9 - CO outlet air damper; 10 - CO bypass; 11 - CO bypass air damper; 12 - SCR reactor; 13 - flue gas heat exchanger; 14 - induced draft fan for desulfurization and denitrification; 15 - desulfurization recycle flue; 16 - desulfurization recycle air damper; 101 - thermometer for the desulfurization device; 102 - SO2 concentration detector; 103 - dust concentration detector; 104 - humidity detector; 105 - HCl concentration detector; 106 - thermometer for the CO reactor; 107 - thermometer for the SCR reactor; 201 - CO catalyst; 202 - soot blower for the CO catalyst. Detailed implementation manners

[0033] The technical solution of the present invention will be clearly and completely described below with specific embodiments. It should be understood that the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of the present invention. Unless otherwise defined, all professional and scientific terms used herein have the same meaning as those familiar to those skilled in the art.

[0034] Unless otherwise defined, the technical terms or scientific terms used herein shall have the ordinary meaning understood by those of ordinary skill in the art to which the present invention pertains. Terms such as "connected", "linked" or "communicated" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Upper", "lower", "left", "right", etc. are only used to represent relative positional relationships, and when the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0035] See Figure 1, the CO removal device by coupled sintering provided by the present invention includes a desulfurization device 2, a dust collector 3, a flue gas heater 5, a CO reaction section, and an SCR reactor 12. The flue gas heater 5 is used to heat the flue gas. The desulfurization device 2 and the flue gas heating device 5 are respectively arranged upstream and downstream of the dust collector 3 along the flue gas flow direction. The desulfurization device 2 is mainly used to remove SO2, and can also remove trace pollutants, such as heavy metals, dioxins, etc. by injecting a special CO adsorbent. At the same time, the HCl removal efficiency can also be improved by injecting an HCl removal agent. Preferably, a desulfurization device thermometer 101 is provided on the desulfurization device 2. Trace pollutants are generally difficult to directly detect, but the operating temperature of the desulfurization device is used as a judgment index. When the operating temperature of the desulfurization device is too high, the removal ability of trace pollutants will decrease, and at this time, an adsorbent needs to be injected to assist in the removal. The dust collector 3 is used to remove dust from the flue gas. An SO2 concentration detector 102, a dust concentration detector 103, a humidity detector 104, and an HCl concentration detector 105 are arranged on the connecting pipeline between the dust collector 3 and the flue gas heater 5. In this way, the SO2 concentration, dust concentration, humidity, and HCl concentration in the flue gas can be detected, and the operating control mode of the CO removal device by coupled sintering can be guided and adjusted according to the obtained values. The CO reaction section is connected downstream of the flue gas heater along the flue gas flow direction. The SCR reactor is connected downstream of the CO reaction section along the flue gas flow direction and is used for denitrifying the flue gas. During operation, the flue gas to be CO-removed is sequentially introduced into the desulfurization device, the dust collector, and the flue gas heater to remove SO2, dust, and heat. The obtained hot flue gas is introduced into the SCR reactor for denitrification after removing CO through the CO reactor on the CO removal gas path or directly introduced into the SCR reactor for denitrification through the CO bypass.

[0036] As Figure 1As shown in the figure, the CO reaction section includes a CO removal gas path 6 and a CO bypass 10 that are connected in parallel. A CO reactor 8 is provided on the CO removal gas path 6. The opening and closing of the CO removal gas path 6 are controlled by a CO inlet air damper 7 provided at the inlet end of the CO reactor 8 and a CO outlet air damper 9 provided at the outlet end of the CO reactor 8. The opening and closing of the CO bypass 10 are controlled by a CO bypass air damper 11 provided on the CO bypass 10. The CO reactor 8 has a cavity structure with a containing space, and the CO catalyst 201 is placed in this cavity. The cavity space size of the CO reactor 8 can be set according to actual needs so that the flue gas in the CO reactor 8 has an appropriate flow rate and more CO catalysts can be placed, thus providing a better reaction environment for the removal of CO in the flue gas and then improving the removal efficiency. The CO catalyst 201 can be set in a group or multiple groups. If multiple groups are set, each group of CO catalysts 201 is arranged at intervals in the CO reactor 8 along the flue gas flow direction. By setting multiple groups of CO catalysts 201, the removal efficiency of CO in the flue gas by the CO reactor 8 can be significantly improved. The active component of the CO catalyst 201 is usually a noble metal, and examples include at least one of Pt, Pd, Rh, Au, Ag, and Ir. In addition, a CO catalyst soot blowing device 202 is also provided in the CO reactor 8 to remove the soot on the surface of the CO catalyst.

[0037] Both the CO removal gas path 6 and the CO bypass 10 control the opening and closing of the flue gas by setting air dampers. Specifically, a CO inlet air damper 7 is provided at the inlet end of the CO reactor 8 in the CO removal gas path 6 and a CO outlet air damper 9 is provided at the outlet end for control, and a CO bypass air damper 11 is provided on the CO bypass 10. When the CO inlet air damper 7 and the CO outlet air damper 9 at both ends of the CO reactor 8 are opened and the CO bypass air damper 11 on the CO bypass 10 is closed, the CO removal gas path 6 is in a conducting state, while the CO bypass 10 is in a closed state. The flue gas is transported in the CO removal gas path 6, and the CO catalyst 201 in the CO reactor 8 removes the CO in the flue gas and then enters the SCR reactor 12 for denitrification reaction. When the CO inlet air damper 7 and the CO outlet air damper 9 at both ends of the CO reactor 8 are closed and the CO bypass air damper 11 on the CO bypass 10 is opened, the CO removal gas path 6 is in a closed state, while the CO bypass 10 is in a conducting state, and the CO directly enters the SCR reactor 12 through the CO bypass 10 to achieve flue gas denitrification.

[0038] As Figure 1As shown, the coupled sintering CO removal device further includes a flue gas heat exchanger 13 for heat exchanging the flue gas led out from the dust collector 3 and the SCR reactor 12. In this way, the waste heat generated by the coupled sintering CO removal device itself can be fully utilized to heat the flue gas, making full use of energy. The flue gas flowing out of the dust collector 3 is heat exchanged in the flue gas heat exchanger 13. The flue gas after heat exchange in the flue gas heat exchanger 13 is heated again by the flue gas heater 5 and then flows into the CO reaction section. Then, according to actual needs, the flue gas is controlled to flow into the CO removal gas path 6 or the CO bypass 10 of the CO reaction section through the CO inlet damper 7, the CO outlet damper 9, and the CO bypass damper 11, and then flows into the SCR reactor 12 for denitrification reaction. The flue gas heat exchanger 13 heats the flue gas once, and the flue gas heater 5 heats the flue gas again, ensuring the temperatures required for the normal operation of the CO reactor 8 and the SCR reactor 12. In addition, the flue gas heat exchanger 13 is preferably a GGH heat exchanger (Gas Gas Heater).

[0039] The SCR reactor 12 is connected downstream of the CO reaction section along the flue gas flow direction for denitrifying the flue gas. The SCR reactor 12 also has a cavity structure with an accommodation space, and the SCR catalyst is placed in this cavity. The outlet of the SCR reactor 12 is preferably connected to the flue gas heat exchanger 13. Similarly, a group of SCR catalysts can be provided, or multiple groups can be provided. Each group of SCR catalysts is spaced along the flue gas flow direction in the inner cavity of the SCR reactor 12, enhancing the denitrification ability and working efficiency of the SCR reactor 12 for the flue gas through multiple groups of SCR catalysts. The active components of the SCR catalyst can be noble metals and / or transition metals. Among them, the noble metals can include at least one of Pt, Pd, Rh, Au, Ag, and Ir. The transition metals can include at least one of V, Fe, Cu, Ce, and Co. The SCR catalyst can be a vanadium-titanium-based catalyst.

[0040] In a preferred embodiment, the coupled sintering CO removal device further includes a desulfurization circulation flue 15 for circulating the flue gas led out from the SCR reactor 12 to the desulfurization device 2. At this time, the flue gas led out from the SCR reactor can also be returned to the desulfurization device 2 for circulating treatment. A desulfurization circulation damper 16 is provided on the desulfurization circulation flue 15, and the desulfurization circulation damper 16 can control the closing and opening of the desulfurization circulation flue 15.

[0041] In addition, the coupled sintering CO removal device provided by the present invention generally further includes a desulfurization and denitrification induced draft fan 14, which can generate negative pressure by the rotation of the impeller, extract the flue gas in the SCR reactor 12, and discharge the flue gas after denitrification in the SCR reactor 12 or return it to the desulfurization device 2 for circulating treatment, thereby ensuring the normal operation of the coupled sintering CO removal device.

[0042] In a preferred embodiment, the coupled sintering CO removal device further includes a sintering machine 1, which is connected upstream of the desulfurization device 2 along the flue gas flow direction and is used to provide sintering flue gas.

[0043] The operation of the CO removal device is closely related to the desulfurization and denitrification device. The operation status of desulfurization and denitrification affects the service life of the CO catalyst, and comprehensive consideration is required. However, the existing operation control methods do not consider the overall control methods of the CO removal device and the upstream desulfurization and dust removal device during the start-up and operation stages, which will affect the service life of the CO catalyst.

[0044] The operation control method of the coupled sintering CO removal device provided by the present invention has carried out a detailed design of the control method from three stages: the start-up stage, the operation stage, and the shutdown stage. The specific control methods are as follows:

[0045] (1) Control during the start-up stage:

[0046] Before the start-up (start) of the sintering machine 1, it is necessary to preheat and raise the temperature of the coupled sintering CO removal device 4-5 hours in advance to remove the liquid water in the coupled sintering CO removal device. After start-up, the CO bypass and the optional desulfurization recycle flue are conducted to establish an internal flue gas circulation, the CO removal gas path is closed, and the flue gas heating device is started to preheat and raise the temperature of the SCR reactor. Among them, the temperature for preheating and raising the temperature of the SCR reactor is preferably 100-150 °C, and the duration at the preheating temperature is preferably 1-2 hours. After the SCR reactor is preheated and raised to the temperature, then the humidity of the flue gas at the outlet of the dust collector is detected by a humidity detector. After the humidity no longer changes, the CO removal gas path is conducted, the CO bypass is closed, and the low-humidity high-temperature flue gas is introduced into the CO reactor to preheat and raise the temperature of the CO reactor. After the CO reactor reaches the designed operating temperature, the CO bypass is conducted and the CO removal gas path is closed to isolate the CO reactor from the flue gas. At this time, the liquid water in the coupled sintering CO removal device can be well removed to avoid the adverse effect of the liquid water adhering to the surface of the catalyst on the CO catalyst. In addition, the control method during the start-up stage preferably further includes that in the initial stage of the start-up of the sintering machine, if the concentrations of SO2, dust, H2O, and HCl in the flue gas at the outlet of the dust collector are lower than the threshold value and exceed the duration threshold value, it means that the CO device has good start-up conditions. At this time, the CO adsorbent is put into the desulfurization device to adsorb and remove the trace pollutant components in the flue gas in the initial stage of start-up, and the influence of these trace pollutant components on the service life of the CO catalyst can be avoided at this time. After the CO reactor 8 completes the introduction of the flue gas and operates stably for a period of time (for example, 1-3 hours), the sintering machine 1 generally operates stably, and the input of the CO adsorbent into the desulfurization device 2 is stopped, and the CO reactor 8 enters the stable operation stage. The active components of the CO adsorbent are usually at least one of activated carbon, zeolite, Al2O3, and TiO2.

[0047] (2) Process control during operation:

[0048] Detect the concentrations of SO2, dust, H2O, and HCl through a SO2 concentration detector, a dust concentration detector, a humidity detector, and an HCl concentration detector; when the concentrations of SO2, dust, and H2O in the flue gas at the outlet of the dust collector exceed the threshold and the duration exceeds the threshold, then conduct the CO bypass, close the CO removal gas path, isolate the CO reactor from the flue gas, and when the concentrations of SO2, dust, and H2O in the flue gas at the outlet of the dust collector drop below the threshold and the duration exceeds the threshold, then conduct the CO removal gas path, close the CO bypass, and reintroduce the flue gas into the CO reactor; when the HCl concentration in the flue gas at the outlet of the dust collector exceeds the threshold (20 mg / Nm 3 ) and the duration exceeds the threshold T HCl (0.5 - 2 h), then put the HCl removal agent into the desulfurization device. At this time, the influence of too high concentrations of SO2, dust, H2O, and HCl on the service life of the CO catalyst can be avoided, and the service life of the CO catalyst can be extended.

[0049] The movement process in this stage preferably satisfies the following condition A and / or condition B, and at this time, the CO catalyst can be better protected and the service life of the CO catalyst can be extended:

[0050] A: When the operating temperature t of the desulfurization device s is higher than the set maximum temperature and the duration exceeds the threshold T 脱硫 , then put the CO adsorbent into the desulfurization device. Among them, T 脱硫 is preferably 1.5 - 3 h, such as 1.5 h, 1.8 h, 2 h, 2.2 h, 2.5 h, 2.8 h, 3 h, or any value between them.

[0051] B: When the indexes of the flue gas at the outlet of the dust collector meet the following conditions A` - C`, then conduct the CO bypass, close the CO removal gas path, and isolate the CO reactor from the flue gas. Conversely, conduct the CO removal gas path, close the CO bypass, and introduce the flue gas into the CO reactor. A`: The concentration of SO2 in the flue gas at the outlet of the dust collector is 35 mg / Nm 3 or more and the duration exceeds the threshold T SO2 . B`: The dust concentration in the flue gas at the outlet of the dust collector is 10 mg / Nm 3 or more and the duration exceeds the threshold T 粉层 . C`: The humidity of the flue gas at the outlet of the dust collector is 20% or more and the duration exceeds the threshold T 湿度 . Among them, T SO2 is preferably 0.5 - 2 h, such as 0.5 h, 0.8 h, 1 h, 1.2 h, 1.5 h, 1.8 h, 2 h, or any value between them. T 粉尘Preferably 1 to 2 h, such as 1 h, 1.2 h, 1.5 h, 1.8 h, 2 h or any value therebetween. T 湿度 Preferably 1.5 to 3 h, such as 1.5 h, 1.8 h, 2 h, 2.2 h, 2.5 h, 2.8 h, 3 h or any value therebetween.

[0052] (3) Shutdown process control:

[0053] During shutdown, turn on the CO bypass, close the CO removal gas path, and isolate the CO reactor from the flue gas.

[0054] The present invention will be described in detail below by way of examples.

[0055] In the following examples and comparative examples, the CO catalyst is a commercially available honeycomb noble metal catalyst, and the active components are noble metal materials Pd and Pt. The SCR catalyst is a commercially available vanadium-titanium-based catalyst, and a honeycomb 25-hole catalyst is used. The HCl remover is a commercially available highly active calcium-based absorbent. The adsorbent is activated carbon particles.

[0056] Example 1

[0057] The coupled sintering CO removal device used in this example includes a sintering machine 1 (with a specification of 360 m 2 ), a desulfurization device 2, a dust collector 3, a flue gas heat exchanger 13, a flue gas heater 5, a CO reaction section, an SCR reactor 12, and a desulfurization and denitrification induced draft fan 14, and includes a desulfurization circulation flue 15 for circulating the flue gas led out from the SCR reactor to the desulfurization device, and a desulfurization circulation air damper 16 is provided on the desulfurization circulation flue 15; on the connecting pipeline (dust collector outlet flue 4) between the dust collector 3 and the flue gas heat exchanger 13, a SO2 concentration detector 102, a dust concentration detector 103, a humidity detector 104, and an HCl concentration detector 105 are provided; the CO reaction section includes a CO removal gas path 6 and a CO bypass 10 connected in parallel, a CO reactor 8 is provided on the CO removal gas path 6, the opening and closing of the CO removal gas path 6 are controlled by a CO inlet air damper 7 provided at the inlet end of the CO reactor 8 and a CO outlet air damper 9 provided at the outlet end of the CO reactor, and the opening and closing of the CO bypass 10 are controlled by a CO bypass air damper 11 provided on the CO bypass 10; the flue gas heat exchanger 13 is used for heat exchange of the flue gas led out from the dust collector 3 and the SCR reactor 12. The CO reactor 8 is filled with a CO catalyst 201 and is provided with a CO catalyst soot blowing device 202. The SCR reactor 12 is filled with an SCR catalyst.

[0058] The coupled sintering CO removal device provided in this example is controlled in operation from three stages: the startup stage, the operation stage, and the shutdown stage. Specifically:

[0059] (1) Control during startup phase:

[0060] Before the sintering machine 1 starts, preheat and raise the temperature of the entire coupled sintering CO removal device 4.5 hours in advance to remove the liquid water in the system. First, close the CO inlet damper 7 and the CO outlet damper 9 upstream and downstream of the CO reactor 8, open the CO bypass damper 11 to 100% opening, then start the desulfurization and denitrification induced draft fan 14, and establish a flue gas internal circulation through the desulfurization circulation flue 15, the dust collector outlet flue 4, and the CO bypass 10, and start the flue gas heating device 5 to preheat and raise the temperature of the SCR reactor 12. When the temperature of the SCR reactor 12 rises to 150 °C, maintain it at this temperature for 1 hour to dry the entire device. Real-time detect the flue gas humidity of the dust collector outlet flue 4 through the humidity detector 104. After the flue gas humidity no longer changes, first open the CO outlet damper 9 of the CO reactor 8 to 100% opening, open the CO inlet damper 7, and after the inlet damper opening reaches 100%, close the CO bypass damper 11 opening to 0%, introduce the high-temperature flue gas with low humidity into the CO reactor 8, and start to preheat and raise the temperature of the CO reactor 8. This step can avoid the influence of the condensed water formed by the large flue gas humidity at the initial stage of startup on the CO catalyst 201. After the CO reactor 8 reaches the designed operating temperature, open the CO bypass damper 11 to 100% opening, then close the CO inlet damper 7 to 0% opening, and finally close the CO outlet damper 9 to 0% opening. The flue gas is changed to pass through the CO bypass 10 and does not enter the CO reactor 8. The CO reactor 8 is isolated from the flue gas and maintains a relatively high temperature by its own heat.

[0061] After the preheating of the CO reactor 8 and the SCR reactor 12 is completed, wait for the sintering machine 1 to start. After the flue gas is introduced into the coupled sintering CO removal device, start to measure the SO2, dust, H2O concentration, and HCl concentration in the flue through the SO2 concentration detector 102, the dust concentration detector 103, the humidity detector 104, and the HCl detector 105 set on the dust collector outlet flue 4. If it simultaneously meets that the SO2 concentration is lower than 35 mg / Nm 3 and the duration exceeds 1 hour, the dust concentration is lower than 10 mg / Nm 3 and the duration exceeds 1 hour, the humidity is lower than 20% and the duration exceeds 1 hour, and the HCl concentration is higher than 20 mg / Nm 3For operating conditions that last for more than 1 hour, CO adsorbent is continuously fed into the desulfurization device 2 to adsorb some trace pollutant components in the flue gas at the initial stage of the sintering machine 1 startup, so as to prevent these trace components from affecting the service life of the CO catalyst 201. After 20 minutes of feeding the CO adsorbent, first open the CO outlet damper 9 to 100% opening, then open the CO inlet damper 7 to 100% opening, and finally close the CO bypass damper 11 to 0% opening to introduce the flue gas into the CO reactor 8, completing the startup of the system. This operation can prevent SO2, dust, water vapor, HCl, and complex trace pollutant components at the initial stage of the sintering machine startup from affecting the service life of the CO catalyst. After the CO reactor 8 completes the flue gas introduction and operates stably for 2 hours, the sintering machine 1 generally operates smoothly, and the feeding of CO adsorbent into the desulfurization device 2 stops, and the CO reactor 8 enters the stable operation stage.

[0062] (2) Control during the operation stage:

[0063] During the stable operation of the CO reactor 8, in addition to regulating the temperature fluctuation of the CO reactor 8 caused by the change in the CO concentration in the flue gas, corresponding adjustments also need to be made according to the SO2 concentration, dust concentration, humidity, HCl concentration of the flue gas at the inlet of the CO reactor (outlet of the dust collector), and the operating temperature of the desulfurization device 2 to prevent adverse flue gas conditions from affecting the CO catalyst. Among them, for the conditions of too high SO2, dust, and H2O concentrations, the measure of bypassing the CO reactor 8 is taken to directly avoid the flue gas under adverse conditions. In the condition of too high HCl concentration at the outlet of the dust collector, the HCl concentration is monitored in real time by the HCl concentration detector 105 installed on the flue duct 4 at the outlet of the dust collector, and the concentration is reduced by feeding HCl removal agent into the desulfurization device. When the operating temperature of the desulfurization device is too high, the concentrations of other trace components will increase, and these components are adsorbed by feeding CO adsorbent into the desulfurization device 2 to reduce their concentrations. The specific interlock control method is as follows:

[0064] ① When the SO2 concentration of the flue gas at the outlet of the dust collector 3 is higher than 35 mg / Nm 3 and lasts for more than the threshold value T SO2 (1 h), the CO bypass damper 11 is automatically interlocked to open in sequence, the CO inlet damper 7 is closed, and the CO outlet damper 9 is closed to isolate the CO reactor 8 from the flue gas, preventing the rapid deactivation of the CO catalyst caused by too high SO2 concentration conditions.

[0065] ② When the dust concentration of the flue gas at the outlet of the dust collector 3 is higher than 10 mg / Nm 3 , start recording the duration of too high dust concentration, and simultaneously halve the purge interval period of the CO catalyst soot blowing device 202 to strengthen the purge. When the duration exceeds the threshold value T 粉尘After (1 h), the automatic interlock sequentially opens the CO bypass damper 11, closes the CO inlet damper 7, closes the CO outlet damper 9, isolates the CO reactor 8 from the flue gas, and avoids the blockage of the CO catalyst caused by the high dust concentration condition, thus rapidly deactivating it.

[0066] ③ When the humidity of the flue gas at the outlet of the dust collector 3 is higher than 20%, start recording the duration of the excessive humidity, and simultaneously reduce the desulfurization water injection volume to lower the flue gas humidity. When the duration exceeds the threshold T 湿度 After (1.5 h), the automatic interlock sequentially opens the CO bypass damper 11, closes the CO inlet damper 7, closes the CO outlet damper 9, isolates the CO reactor 8 from the flue gas, and avoids the poisoning and deactivation of the CO catalyst 201 caused by local condensation under the condition of excessive humidity.

[0067] ④ When the HCl concentration of the flue gas at the outlet of the dust collector 3 is higher than 20 mg / Nm 3 Start recording the duration of the excessive HCl concentration. When the duration exceeds the threshold T HCl After (1 h), start adding HCl removal agent into the desulfurization device 2 to enhance the HCl removal effect and avoid the influence of high HCl concentration on the service life of the CO catalyst.

[0068] ⑤ The operating temperature of the desulfurization device 2 affects the synergistic removal effect of multiple pollutants. When the desulfurization operating temperature ts is higher than the set maximum temperature, start recording the duration T of the excessive desulfurization operating temperature 脱硫 (2 h). When the duration exceeds the threshold T 脱硫 After that, start adding CO adsorbent into the desulfurization tower to enhance the adsorption effect of multiple pollutants, avoid the influence of trace flue gas components on the service life of the CO catalyst, and at the same time, this control step can effectively reduce the consumption of the CO adsorbent and lower the operating cost.

[0069] ⑥ For the control operations of ①②③, after isolating the CO reactor 8 from the flue gas and switching to the bypass operation, continue to detect the SO2, dust, H2O, and HCl concentrations at the outlet of the dust collector. When the detected concentrations of all indicators are lower than the allowable maximum value and continue to exceed the duration, then sequentially open the CO inlet damper, the CO outlet damper, and close the CO bypass damper, and reintroduce the flue gas into the CO reactor.

[0070] (3) Control during the shutdown phase:

[0071] During the shutdown process, the flue gas of the sintering machine 1 gradually cools down. The flue gas heating device 5 of the SCR reactor 12 stops heating, the flue gas temperature of the desulfurization device 2 continuously decreases, and the flue gas temperature of the CO reactor 8 also continuously decreases accordingly. When the flue gas temperature of the CO reactor 8 drops below 100 °C, there may be a problem of local condensation causing the CO catalyst 201 to be poisoned and deactivated. To avoid the water vapor in the flue gas from condensing on the surface of the CO catalyst, when the system shuts down, first open the CO bypass damper 11 to 100% opening, then close the CO inlet damper 7 to 0% opening, and finally close the CO outlet damper 9 to 0% opening. The CO reactor 8 is isolated from the flue gas during the shutdown process and maintains a relatively high temperature by relying on its own heat insulation, so that condensation does not occur inside the CO reactor 8. After the desulfurization and denitrification induced draft fan 14 has stopped operating, the subsequent cooling of the CO reactor 8 is mainly caused by heat dissipation from the wall panels to the outside. The temperature of the wall panels is lower than the internal temperature of the CO reactor, and the condensation of the flue gas mainly occurs on the outer wall panels of the reactor and will not appear on the surface of the CO catalyst, effectively avoiding the influence of condensed water on the CO catalyst.

[0072] 360m 2 The flue gas volume produced by the sintering machine is 1,300,000 Nm 3 / h (standard condition), among which, the original carbon monoxide concentration in the flue gas is about 6000 mg / Nm 3 。 By using the coupled sintering CO removal device provided in this embodiment and operating and controlling by the above method, the results show that after treating the sintering flue gas to meet the CO standard (CO concentration is 2800 mg / Nm 3 or less) and discharging for three months, the activity of the CO catalyst has not decreased significantly.

[0073] Example 2

[0074] The coupled sintering CO removal device and the operation control provided in this embodiment are the same as those in Example 1, except that in the startup stage, after preheating the CO reactor 8 and the SCR reactor 12, the concentrations of SO2, dust, H2O and HCl are not detected and no CO adsorbent is put into the desulfurization device 2, and the remaining steps and conditions are the same as those in Example 1. The results show that after treating the sintering flue gas of the same scale to meet the CO standard (CO concentration is 2800 mg / Nm 3 or less) and discharging for three months, the activity of the CO catalyst has decreased by about 5%.

[0075] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and purposes of the present invention.

Claims

1. A coupled sintering CO removal device, characterized in that, Comprising: A desulfurization device for removing SO2 from flue gas; A dust collector connected downstream of the desulfurization device along the flue gas flow direction for dust removal of the flue gas; A flue gas heater connected downstream of the dust collector along the flue gas flow direction for heating the flue gas; an SO2 concentration detector, a dust concentration detector, a humidity detector, and an HCl concentration detector are provided on the connecting pipeline between the flue gas heater and the dust collector; A CO reaction section connected downstream of the flue gas heater along the flue gas flow direction. The CO reaction section includes a CO removal gas path and a CO bypass connected in parallel with each other. A CO reactor is provided on the CO removal gas path. The opening and closing of the CO removal gas path are controlled by a CO inlet air damper provided at the inlet end of the CO reactor and a CO outlet air damper provided at the outlet end of the CO reactor. The opening and closing of the CO bypass are controlled by a CO bypass air damper provided on the CO bypass; An SCR reactor connected downstream of the CO reaction section along the flue gas flow direction for denitrification of the flue gas.

2. The coupled sintering CO removal device according to claim 1, wherein The coupled sintering CO removal device further includes a desulfurization recycle flue for recycling the flue gas led out from the SCR reactor to the desulfurization device, and a desulfurization recycle air damper is provided on the desulfurization recycle flue.

3. The coupled sintering CO removal device according to claim 1, wherein, The coupled sintering CO removal device further includes a flue gas heat exchanger for heat exchange between the flue gas led out from the dust collector and the SCR reactor.

4. The coupled sintering CO removal device according to any one of claims 1 to 3, characterized in that, The coupled sintering CO removal device further includes a sintering machine connected upstream of the desulfurization device along the flue gas flow direction for providing sintering flue gas.

5. The operation control method of the coupled sintering CO removal device according to any one of claims 1 to 4, characterized in that, This method includes sequentially introducing the flue gas to be CO-removed into the desulfurization device, the dust collector, and the flue gas heater to remove SO2, remove dust, and heat. The obtained hot flue gas is introduced into the SCR reactor for denitrification after removing CO through the CO reactor on the CO removal gas path or directly introduced into the SCR reactor for denitrification through the CO bypass. During startup, operation, and shutdown, the following methods are adopted for control: S1. Startup control: After startup, open the CO bypass and optionally the desulfurization recycle flue to establish an internal flue gas circulation, close the CO removal gas path, and start the flue gas heating device to preheat the SCR reactor. Detect the humidity of the flue gas at the outlet of the dust collector through the humidity detector. After the humidity no longer changes, open the CO removal gas path, close the CO bypass, and introduce the low-humidity high-temperature flue gas into the CO reactor to preheat and raise the temperature of the CO reactor. After the CO reactor reaches the designed operating temperature, open the CO bypass and close the CO removal gas path to isolate the CO reactor from the flue gas; S2. Operation process control: Detect the concentrations of SO2, dust, H2O and HCl through the SO2 concentration detector, dust concentration detector, humidity detector and HCl concentration detector; when the concentrations of SO2, dust and H2O in the flue gas at the outlet of the dust collector exceed the thresholds and the duration exceeds the thresholds, then turn on the CO bypass, close the CO removal gas path, isolate the CO reactor from the flue gas, and wait until the concentrations of SO2, dust and H2O in the flue gas at the outlet of the dust collector drop below the thresholds and the duration exceeds the thresholds, then turn on the CO removal gas path, close the CO bypass, and introduce the flue gas into the CO reactor again; when the HCl concentration in the flue gas at the outlet of the dust collector exceeds the threshold and the duration exceeds the threshold, then put the HCl removal agent into the desulfurization device. S3. Shutdown process control: During shutdown, turn on the CO bypass, close the CO removal gas path, and isolate the CO reactor from the flue gas.

6. The operating control method of the coupled sintering CO removal device according to claim 5, characterized in that, This method also includes that in the initial stage of the sintering machine startup, if the concentrations of SO2, dust, H2O and HCl in the flue gas at the outlet of the dust collector are already lower than the thresholds and the duration exceeds the thresholds, then put the CO adsorbent into the desulfurization device to adsorb and remove the trace pollutant components in the flue gas in the initial startup stage.

7. The operation control method of the coupled sintering CO removal device according to claim 5, wherein, During startup, the temperature for the SCR reactor to heat up and preheat is 100 - 150 °C, and the duration at the preheating temperature is 1 h - 2 h.

8. The operation control method of the coupled sintering CO removal device according to claim 5, characterized in that, During the operation process, the following condition A and / or condition B are satisfied: A: When the operating temperature t of the desulfurization device s is higher than the set maximum temperature and the duration exceeds the threshold T 脱硫 then a CO adsorbent is put into the desulfurization device; B: When the indexes of the flue gas at the outlet of the dust collector meet the following conditions A` - C`, then turn on the CO bypass, close the CO removal gas path, and isolate the CO reactor from the flue gas; otherwise, turn on the CO removal gas path, close the CO bypass, and introduce the flue gas into the CO reactor; A`: The concentration of SO2 in the flue gas at the outlet of the dust collector is 35 mg / Nm 3 or above and the duration exceeds the threshold T SO2 ; B`: The dust concentration in the flue gas at the outlet of the dust collector is 10 mg / Nm 3 or more and the duration exceeds the threshold value T 粉层 ; C`: The humidity in the flue gas at the outlet of the dust collector is above 20% and the duration exceeds the threshold T 湿度 .

9. The operation control method of the coupled sintering CO removal device according to claim 8, characterized in that, T 脱硫 is 1.5 to 3 h; T SO2 is 0.5 to 2 h; T 粉尘 is 1 to 2 h; T 湿度 is 1.5 to 3 h.

10. The operation control method of the coupled sintering CO removal device according to any one of claims 5 to 9, characterized in that, The way to switch from the CO removal gas path being turned on and the CO bypass being closed to the CO removal gas path being closed and the CO bypass being turned on is to sequentially open the CO bypass damper, close the CO inlet damper, and close the CO outlet damper; The way to switch from the CO removal gas path being closed and the CO bypass being turned on to the CO removal gas path being turned on and the CO bypass being closed is to sequentially open the CO outlet damper, open the CO inlet damper, and close the CO bypass damper.

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