Low-temperature flue gas purification system
By designing a low-temperature flue gas purification system, utilizing bypass and circulating flue damper control, and combining flue gas heating devices and CO catalysts, the problems of catalyst poisoning and temperature fluctuation caused by low-temperature flue gas during main unit start-up are solved, achieving CO emission reduction and safe operation of the heat exchanger.
Patent Information
- Application Number
- CN202423258394.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-27
- Publication Date
- 2025-12-05
- Estimated Expiration
- 2034-12-27
AI Technical Summary
During the start-up of the main unit, the liquid water and high concentration of sulfur oxides in the low-temperature flue gas poison the CO catalyst, and the flue gas temperature fluctuations cause the rotary flue gas heat exchanger to jam, which is difficult to solve effectively with existing technology.
A low-temperature flue gas purification system is adopted, including a heat exchanger, a flue gas heating device, and a reactor. The system controls the temperature of the flue gas through the bypass flue and the circulating flue, combined with the flue gas heating device. The CO catalyst is used to react in the reactor to form CO2. Temperature measuring instruments and wind speed detectors and controllers are provided for automatic adjustment.
It effectively avoids the poisoning of the catalyst by liquid water and sulfur oxides in low-temperature flue gas. During the flue gas temperature rise, the temperature of the reactor is gradually controlled. During the flue gas temperature rise, the heat release of the CO catalytic combustion reaction is gradually resolved, thus achieving CO emission reduction and safe operation of the heat exchanger.
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Figure CN223636186U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to the field of environmental protection, and more particularly to a low-temperature flue gas purification system. BACKGROUND
[0002] At present, the domestic sintering and pellet, thermal power, coking, carbon, metal smelting, chemical industry and the like have basically completed the desulfurization and denitrification ultra-low emission transformation. CO is the largest pollutant in current emissions, and the treatment technology for CO includes oxygen-enriched combustion, steam injection, flue gas recirculation, combustion optimization and the like, but the removal efficiency of these methods is limited, and the CO catalytic oxidation combustion method is highly concerned as a high-efficiency technology, and its removal efficiency can reach more than 80%.
[0003] The CO catalytic oxidation combustion technology refers to that the flue gas with a certain temperature (> 240℃) passes through a specific CO catalyst, and the CO generates CO2 on the surface of the catalyst through an exothermic reaction. Therefore, the flue gas temperature at the outlet of the catalyst layer is often higher, which is easy to cause the jamming of the rotary flue gas heat exchanger.
[0004] The existing research shows that the H2O in the gas can change the surface morphology structure of the CO catalyst, causing irreversible loss of part of the active sites; the sulfur oxides have a toxic effect on the CO catalyst, because the sulfur oxides can form sulfates on the surface of the catalyst carrier to weaken the active sites, affect the Pt-CO bonding, and weaken the adsorption of Pt to CO. That is to say, the application conditions of the CO catalyst are harsh, and if the flue gas contains liquid water and sulfur oxides, both of which will have a toxic effect on the catalyst.
[0005] At present, the domestic various industries have basically completed the desulfurization and denitrification ultra-clean emission transformation, and there are active coke integrated desulfurization and denitrification devices, sodium bicarbonate dry desulfurization devices and the like. If CO emission reduction is to be achieved, an independent CO removal device needs to be added after the desulfurization and denitrification device to achieve efficient removal of CO. Under the main engine starting condition, the flue gas temperature is low, and a large amount of liquid water is carried, and at the same time, the desulfurization and denitrification device has not been completely stabilized and put into operation, and the sulfur oxide emission concentration in the flue gas is unstable, and a large amount of sulfur oxides are contained in the flue gas entering the CO removal device. Therefore, under the main engine starting condition, how to reduce the influence of the low-temperature flue gas on the CO catalyst, how to control the flue gas temperature rise, and how to reduce the influence of the high-temperature flue gas after catalytic combustion on the safe operation of the rotary flue gas heat exchanger are problems to be solved urgently. INVENTION CONTENTS
[0006] The utility model aims at providing a low-temperature flue gas purification system, which can avoid the influence of the liquid water and high-concentration sulfur oxides contained in the low-temperature flue gas on the catalyst, and solve the problem of heat exchanger blockage caused by flue gas temperature fluctuation.
[0007] To solve the above technical problems, the utility model adopts the following technical scheme.
[0008] The utility model provides a kind of low-temperature flue gas purification system, the low-temperature flue gas purification system includes heat exchanger, flue gas heating device and reactor, the flue gas inlet of the original flue gas side of heat exchanger is used to connect the flue gas outlet of desulfurization and denitrification device, the flue gas inlet of the desulfurization and denitrification device connects the flue gas outlet of main machine, the flue gas outlet of the original flue gas side of heat exchanger connects the flue gas inlet of the flue gas heating device, the flue gas outlet of the flue gas heating device is connected by reactor inlet flue the flue gas inlet of the reactor, catalyst is equipped in the reactor, the flue gas outlet of the flue gas heating device is also connected by bypass flue the flue gas inlet of the clean flue gas side of heat exchanger, the flue gas outlet of the reactor connects the flue gas inlet of the clean flue gas side of heat exchanger, the flue gas outlet of the clean flue gas side of heat exchanger is used to discharge clean flue gas outward, the flue gas outlet of the clean flue gas side of heat exchanger is also connected by circulating flue the flue gas inlet of the original flue gas side of heat exchanger, adjustable reactor inlet flue damper is equipped on the reactor inlet flue, adjustable bypass flue damper is equipped on the bypass flue, adjustable circulating flue damper is equipped on the circulating flue.
[0009] Some embodiments of the present application, the flue gas inlet, flue gas outlet of the original flue gas side of the heat exchanger and the flue gas inlet, flue gas outlet of the clean flue gas side of the heat exchanger are provided with temperature detector.
[0010] Some embodiments of the present application, the reactor inlet flue is provided with reactor inlet air velocity detector, the bypass flue is provided with bypass flue air velocity detector, and the circulating flue is provided with circulating flue air velocity detector.
[0011] Some embodiments of the present application, the low-temperature flue gas purification system further comprises a controller;
[0012] The controller is signal connected to each of the temperature detector, the reactor inlet air velocity detector, the bypass flue air velocity detector and the circulating flue air velocity detector, and the controller controls the reactor inlet damper, the bypass flue damper and the circulating flue damper.
[0013] Some embodiments of the present application, the low-temperature flue gas purification system further comprises an induced draft fan;
[0014] The flue gas outlet of the clean flue gas side of the heat exchanger is connected to the flue gas inlet of the induced draft fan;
[0015] The flue gas outlet of the induced draft fan is used to discharge clean flue gas outward, and the flue gas outlet of the induced draft fan is also connected by circulating flue the flue gas inlet of the original flue gas side of the heat exchanger.
[0016] Some embodiments of the present application, the low-temperature flue gas purification system further comprises a chimney;
[0017] The flue gas outlet of the induced draft fan is connected to the chimney, and the clean flue gas is discharged outward through the chimney.
[0018] In some embodiments of the present application, the reactor is provided with a plurality of shelves arranged at intervals along the flow direction of the flue gas, and the shelves are used to place the catalyst.
[0019] In some embodiments of the present application, the desulfurization and denitrification device is one of a wet desulfurization and denitrification device, a semi-dry desulfurization and denitrification device, or a dry desulfurization and denitrification device.
[0020] In some embodiments of the present application, the heat exchanger is a rotary flue gas heat exchanger.
[0021] In some embodiments of the present application, the catalyst is one or more of a carbon monoxide removal catalyst, a methane removal catalyst, and a non-methane total hydrocarbon removal catalyst.
[0022] From the above technical solution, the embodiments of the present application have at least the following advantages and positive effects:
[0023] In the low-temperature flue gas purification system, the catalyst in the reactor is a carbon monoxide removal catalyst, taking the purification of carbon monoxide in flue gas as an example.
[0024] Under the main engine starting condition, the desulfurization and denitrification device has not been formally put into operation, and the flue gas temperature has not reached the CO catalyst light-off temperature.
[0025] At this time, the bypass flue damper and the circulating flue damper are opened, and the flue gas heating device is also opened, and the flue gas circulates between the heat exchanger, the bypass flue, and the circulating flue.
[0026] During the flue gas warming process, the reactor inlet flue damper is gradually opened, and at the same time, the bypass flue damper and the circulating flue damper are gradually closed.
[0027] Because the CO catalytic combustion reaction releases a large amount of heat, and the CO concentration in the flue gas is in a fluctuating state, if the CO concentration in the flue gas is too high, it will inevitably lead to the flue gas inlet temperature of the clean flue gas side of the heat exchanger being higher than the design value. In order to avoid the heat exchanger from being jammed due to the excessively high flue gas temperature, and to avoid safety hazards, at this time, the bypass flue damper needs to be opened, so that part of the flue gas does not pass through the CO catalyst and directly enters the flue gas inlet of the clean flue gas side of the heat exchanger, thereby reducing the flue gas temperature of the flue gas inlet of the clean flue gas side of the heat exchanger and realizing the control of the flue gas temperature. By setting up the bypass flue and the circulating flue, the influence of the low flue gas temperature on the CO catalyst under the main engine starting condition and the temperature regulation problem in the system operation process can be effectively solved. BRIEF DESCRIPTION OF DRAWINGS
[0028] The various objects, features and advantages of the present application will become more apparent from the following detailed description of preferred embodiments of the present application, when considered in conjunction with the accompanying drawings. The drawings are not necessarily to scale, and in some instances, various components of the present application can be shown exaggerated in relation to other components for the purpose of illustration. In the drawings:
[0029] Figure 1 is a structural schematic diagram of a low-temperature flue gas purification system according to an exemplary embodiment.
[0030] The reference signs are explained as follows: 1, main engine; 2, desulfurization and denitrification device; 3, low-temperature flue gas purification system; 4, induced draft fan; 31, heat exchanger; 32, flue gas heating device; 33, reactor; 34, reactor inlet flue; 35, bypass flue; 36, circulating flue; 37, reactor inlet flue damper; 38, bypass flue damper; 39, circulating flue damper; 311, flue gas inlet of the raw flue gas side of the heat exchanger; 312, flue gas outlet of the raw flue gas side of the heat exchanger; 313, flue gas inlet of the clean flue gas side of the heat exchanger; 314, flue gas outlet of the clean flue gas side of the heat exchanger. DETAILED DESCRIPTION
[0031] While the present application can be susceptible to various modifications and alternative forms, the drawings and the description thereof are only intended to illustrate and not to limit the present application. Specific embodiments of the present application are described in detail in the specification and drawings.
[0032] Thus, one feature that is described in the specification will be used to illustrate one feature of an embodiment of the application, and not necessarily all embodiments of the application. Moreover, it should be noted that the specification describes many features. Although certain features can be combined together in order to show possible system designs, these features can also be used in other combinations that are not explicitly described. Thus, the described combinations are not intended to be limiting unless otherwise noted.
[0033] In the embodiments shown in the drawings, the indications of direction, such as up, down, left, right, front and back, are used to explain the structure and movement of various elements of the application are not absolute but relative. These indications are appropriate when the elements are in the positions shown in the drawings. If the positions of the elements change, the indications of direction also change accordingly.
[0034] Please refer to Figure 1 , Figure 1 is a structural schematic diagram of a low-temperature flue gas purification system 3 according to an exemplary embodiment.
[0035] The low-temperature flue gas purification system 3 comprises a heat exchanger 31, a flue gas heating device 32 and a reactor 33, the flue gas inlet 311 of the original flue gas side of the heat exchanger is used to connect the flue gas outlet of the desulfurization and denitrification device 2, the flue gas inlet of the desulfurization and denitrification device 2 is connected to the flue gas outlet of the main machine 1, the flue gas outlet of the original flue gas side of the heat exchanger is connected to the flue gas inlet of the flue gas heating device 32, the flue gas outlet of the flue gas heating device 32 is connected to the flue gas inlet of the reactor 33 through the reactor inlet flue 34, the reactor 33 is provided with a catalyst, the flue gas outlet of the flue gas heating device 32 is also connected to the flue gas inlet 313 of the clean flue gas side of the heat exchanger through the bypass flue 35, the flue gas outlet of the reactor 33 is connected to the flue gas inlet 313 of the clean flue gas side of the heat exchanger, the flue gas outlet 314 of the clean flue gas side of the heat exchanger is used to discharge the clean flue gas to the outside, the flue gas outlet 314 of the clean flue gas side of the heat exchanger is also connected to the flue gas inlet 311 of the original flue gas side of the heat exchanger through the circulating flue 36, the reactor inlet flue 34 is provided with an adjustable reactor inlet flue damper 37, the bypass flue 35 is provided with an adjustable bypass flue damper 38, and the circulating flue 36 is provided with an adjustable circulating flue damper 39.
[0036] Through the above structural design, taking carbon monoxide in the flue gas as an example, the catalyst in the reactor 33 is a carbon monoxide removal catalyst.
[0037] In the main machine 1 starting condition, the desulfurization and denitrification device 2 has not been formally put into operation, and the flue gas temperature has not reached the CO catalyst light-off temperature, in order to avoid that the flue gas temperature is too low, the liquid water and sulfur oxides in the flue gas cause poisoning to the CO catalyst.
[0038] At this time, the bypass flue damper 38 and the circulating flue damper 39 are opened, and the flue gas heating device 32 is opened, and the flue gas circulates between the heat exchanger 31, the bypass flue 35 and the circulating flue 36. The flue gas is heated by the heat exchanger 31 and the flue gas heating device 32. The influence of liquid water and high concentration of sulfur oxides in low temperature flue gas on the CO catalyst can be avoided.
[0039] During the process of heating the flue gas, the reactor inlet flue damper 37 is gradually opened, and the bypass flue damper 38 and the circulating flue damper 39 are gradually closed. When the flue gas temperature and the concentration of sulfur oxides are stable, the bypass flue damper 38 and the circulating flue damper 39 are completely closed. At this time, the CO in the flue gas gradually reacts to form CO2 under the action of the CO catalyst, realizing the emission reduction of CO.
[0040] Due to the large heat release of the CO catalytic combustion reaction, and the CO concentration in the flue gas is in a fluctuating state, if the CO concentration in the flue gas is too high, it will inevitably lead to the temperature of the flue gas inlet 313 of the clean flue gas side of the heat exchanger being higher than the design value. In order to avoid the high flue gas temperature causing the heat exchanger 31 to jam, and to avoid safety hazards, the bypass flue damper 38 needs to be opened at this time, so that part of the flue gas does not pass through the CO catalyst and directly enters the flue gas inlet 313 of the clean flue gas side of the heat exchanger, reducing the flue gas temperature of the flue gas inlet 313 of the clean flue gas side of the heat exchanger, and realizing the control of the flue gas temperature. By setting the bypass flue 35 and the circulating flue 36, the influence of low flue gas temperature on the CO catalyst under the starting condition of the main machine 1 and the temperature control problem during the system operation can be effectively solved.
[0041] The flue gas inlet 311 and the flue gas outlet 312 of the original flue gas side of the heat exchanger and the flue gas inlet 313 and the flue gas outlet 314 of the clean flue gas side of the heat exchanger are provided with temperature measuring instruments. Through the temperature measuring instrument, the current flue gas temperature can be accurately grasped, providing a reference for adjusting the reactor 33 inlet damper, the bypass flue damper 38 and the circulating flue damper 39. Specifically,
[0042] During the process of heating the flue gas, when the temperature of the flue gas outlet 312 of the original flue gas side of the heat exchanger reaches 150℃ or above, the reactor inlet flue damper 37 is gradually opened, and the bypass flue damper 38 and the circulating flue damper 39 are gradually closed.
[0043] The reactor 33 inlet flue 34 is provided with a reactor 33 inlet air speed detector, the bypass flue 35 is provided with a bypass flue 35 air speed detector, and the circulating flue 36 is provided with a circulating flue 36 air speed detector. Through the air speed detector, the air speed in the flue can be accurately understood, so that the reactor 33 inlet damper, the bypass flue damper 38 and the circulating flue damper 39 can be accurately adjusted. The air speed detector includes but is not limited to a heat-sensitive air speed detector, a vane-type air speed detector, a pitot tube air speed detector, etc.
[0044] The low-temperature flue gas purification system 3 further comprises a controller, which is signal-connected to each temperature detector, the reactor 33 inlet air speed detector, the bypass flue 35 air speed detector, and the circulating flue 36 air speed detector, and controls the reactor 33 inlet air baffle, the bypass flue air baffle 38, and the circulating flue air baffle 39. Based on the controller, a control system is formed, and a program can be set to automatically adjust the reactor 33 inlet air baffle, the bypass flue air baffle 38, and the circulating flue air baffle 39 according to the flue gas temperature and air speed, so as to realize equipment automation and reduce labor cost.
[0045] The low-temperature flue gas purification system 3 further comprises an induced draft fan 4, the flue gas outlet 314 of the clean flue gas side of the heat exchanger is connected to the flue gas inlet of the induced draft fan 4, the flue gas outlet of the induced draft fan 4 is used for discharging the clean flue gas to the outside, and the flue gas outlet of the induced draft fan 4 is further connected to the flue gas inlet 311 of the raw flue gas side of the heat exchanger through the circulating flue 36. The induced draft fan 4 generates negative pressure to provide power for the flow of flue gas.
[0046] The low-temperature flue gas purification system 3 further comprises a chimney, the flue gas outlet of the induced draft fan 4 is connected to the chimney, and the clean flue gas is discharged to the outside through the chimney. It should be noted that the chimney is connected to the external environment, and the circulating flue 36 is in a negative pressure state during the starting stage, so that during the flue gas circulation stage, the flue gas passing through the induced draft fan 4 mainly enters the circulating flue 36 to participate in flue gas circulation, and the flue gas is warmed up through flue gas heat exchange and heat supplement.
[0047] The reactor 33 is provided with a plurality of shelves arranged at intervals along the flow direction of the flue gas, and the shelves are used for placing catalysts. The number of catalysts on the shelves can be adjusted according to the purification amount of the flue gas.
[0048] It should be noted that the above embodiment is described by taking removal of carbon monoxide in flue gas as an example, and therefore the catalyst is a carbon monoxide removal catalyst. The low-temperature flue gas purification system 3 can also be used for removal of other gases, for example, it is also applicable to removal of methane, and the corresponding catalyst is replaced by a methane removal catalyst, and for example, it is also applicable to removal of non-methane total hydrocarbon, and the corresponding catalyst is replaced by a non-methane total hydrocarbon removal catalyst. Moreover, the types of catalysts placed in the reactor 33 are not limited to one kind, and can also be a combination of multiple catalysts.
[0049] The low-temperature flue gas purification system 3 can be safely and independently operated, and can be coupled with various types of desulfurization and denitrification devices 2 in different industries, which can be one of a wet desulfurization and denitrification device 2, a semi-dry desulfurization and denitrification device 2, or a dry desulfurization and denitrification device 2. For example, but not limited to, an active coke integrated desulfurization and denitrification device 2, a sodium bicarbonate dry desulfurization device, etc.
[0050] The main machine 1 can be an incinerator in the petrochemical industry, the steel sintering industry, the industrial kiln industry, etc. The heat exchanger 31 can be a rotary flue gas heat exchanger 31.
[0051] By setting the reactor inlet flue damper 37, bypass flue damper 38, circulating flue damper 39, full working condition operation can be met, avoid start and stop machine and low temperature of flue gas, cause CO catalyst poisoning, ensure the catalytic efficiency of CO catalyst. Also can close the reactor inlet flue damper 37 without affecting the original desulfurization and denitrification device 2 operation, open the bypass flue damper 38 to realize the on-line replacement and maintenance of CO catalyst. By adjusting the bypass flue damper 38, the flue gas is divided, the flue gas temperature control purpose is realized under the condition of ensuring the removal efficiency.
[0052] Although the utility model has been described with reference to several exemplary embodiments, it should be understood that the terms used are illustrative and exemplary, rather than limiting terms. Since the utility model can be embodied in various forms without departing from the spirit or essence of the utility model, it should be understood that the above embodiments are not limited to any of the foregoing details, but should be interpreted broadly within the spirit and scope of the appended claims, and therefore all changes and modifications falling within the scope of the claims or their equivalents should be covered by the appended claims.
Claims
1. A low temperature flue gas cleaning system, characterized in that The low-temperature flue gas purification system comprises a heat exchanger, a flue gas heating device and a reactor, the flue gas inlet of the original flue gas side of the heat exchanger is connected with the flue gas outlet of a desulfurization and denitrification device, the flue gas inlet of the desulfurization and denitrification device is connected with the flue gas outlet of a main machine, the flue gas outlet of the original flue gas side of the heat exchanger is connected with the flue gas inlet of the flue gas heating device, the flue gas outlet of the flue gas heating device is connected with the flue gas inlet of the reactor through a reactor inlet flue, the reactor is provided with a catalyst, the flue gas outlet of the flue gas heating device is also connected with the flue gas inlet of the clean flue gas side of the heat exchanger through a bypass flue, the flue gas outlet of the reactor is connected with the flue gas inlet of the clean flue gas side of the heat exchanger, the flue gas outlet of the clean flue gas side of the heat exchanger is used for discharging clean flue gas, the flue gas outlet of the clean flue gas side of the heat exchanger is also connected with the flue gas inlet of the original flue gas side of the heat exchanger through a circulating flue, an adjustable reactor inlet flue damper is arranged on the reactor inlet flue, an adjustable bypass flue damper is arranged on the bypass flue, and an adjustable circulating flue damper is arranged on the circulating flue.
2. The cryogenic flue gas cleaning system of claim 1, wherein, The flue gas inlet and the flue gas outlet of the original flue gas side of the heat exchanger and the flue gas inlet and the flue gas outlet of the clean flue gas side of the heat exchanger are all provided with temperature detectors.
3. The low temperature flue gas cleaning system according to claim 2, characterized in that, A reactor inlet air speed detector is arranged on the reactor inlet flue, a bypass flue air speed detector is arranged on the bypass flue, and a circulating flue air speed detector is arranged on the circulating flue.
4. The low temperature flue gas cleaning system according to claim 3, characterized in that, The low-temperature flue gas purification system further comprises a controller. The controller is connected with the temperature detectors, the reactor inlet air speed detector, the bypass flue air speed detector and the circulating flue air speed detector, and the controller controls the reactor inlet flue damper, the bypass flue damper and the circulating flue damper.
5. The cryogenic flue gas cleaning system of claim 1, wherein, The low-temperature flue gas purification system further comprises an induced draft fan. The flue gas outlet of the clean flue gas side of the heat exchanger is connected with the flue gas inlet of the induced draft fan. The flue gas outlet of the induced draft fan is used for discharging clean flue gas, and the flue gas outlet of the induced draft fan is also connected with the flue gas inlet of the original flue gas side of the heat exchanger through a circulating flue.
6. The cryogenic flue gas cleaning system of claim 5, wherein, The low-temperature flue gas purification system further comprises a chimney. The flue gas outlet of the induced draft fan is connected with the chimney, and clean flue gas is discharged through the chimney.
7. The cryogenic flue gas cleaning system of claim 1, wherein, The reactor is provided with a plurality of shelves arranged at intervals along the flow direction of flue gas, and the shelves are used for placing the catalyst.
8. The cryogenic flue gas cleaning system of claim 1, wherein, The desulfurization and denitrification device is one of a wet desulfurization and denitrification device, a semi-dry desulfurization and denitrification device or a dry desulfurization and denitrification device.
9. The cryogenic flue gas cleaning system of claim 1, wherein, The heat exchanger is a rotary flue gas heat exchanger.
10. The cryogenic flue gas cleaning system of claim 1, wherein, The catalyst is one or more of a carbon monoxide removal catalyst, a methane removal catalyst and a non-methane total hydrocarbon removal catalyst.