A device and process for full-load catalytic reduction-oxidation coupling reaction of combustion flue gas

Abstract

This invention provides a full-load catalytic reduction-oxidation coupled reaction device and process for combustion flue gas. The device includes a reduction-oxidation coupled reactor and an inlet flue located at the inlet of the reactor. Three sets of guide vanes are arranged along the flow direction of the combustion flue gas within the inlet flue. Three to four layers of catalyst modules are arranged along the flow direction of the combustion flue gas within the reduction-oxidation coupled reactor. The inlet flue includes an incoming flue, an outgoing flue, and a deflection bend between the incoming and outgoing flues. The three sets of guide vanes are respectively located within the incoming flue, at the deflection bend, and within the outgoing flue. The second and third sets of guide vanes are telescopic, capable of retracting or extending according to the load of the combustion flue gas source equipment. This invention can achieve NOx and Hg control. 0 It can efficiently and synergistically remove multiple pollutants such as dioxins and VOCs, and can ensure stable operation of the unit under full load conditions.

Description

Technical Field

[0001] This invention relates to a full-load catalytic reduction-oxidation coupled reaction device and process for combustion flue gas, belonging to the field of combustion flue gas purification and treatment technology in the steel industry. Background Technology

[0002] The flue gas from the steel industry contains a large amount of NO. x Air pollution is characterized by a variety of pollutants, including heavy metals (such as hydrogen monoxide), dioxins, and volatile organic compounds (VOCs), making pollution control extremely difficult.

[0003] Current air pollution control efforts are gradually shifting from conventional pollutants (PM, SO2, NO) x The control of pollutants is shifting towards the joint control of conventional and unconventional pollutants (such as dioxins, heavy metals like hydrogen sulfide, and VOCs); and from the efficient removal of single pollutants at the end of the emission process to a new concept of efficient synergistic removal of multiple pollutants. Taking iron and steel sintering flue gas as an example, the pollutants emitted include NO... x The presence of pollutants such as dioxins, CO, and VOCs often presents new challenges for the control of pollutant emissions.

[0004] Existing flue gas treatment systems have the following problems: (1) they are difficult to adapt to load changes and cannot guarantee stable operation under full load conditions; (2) they are mostly designed for single pollutant control and are difficult to achieve synergistic control of multiple pollutants. Therefore, developing a high-efficiency synergistic control device for multiple pollutants in combustion flue gas of the steel industry has important theoretical significance and application prospects.

[0005] Prior art related to this invention:

[0006] The technical solution of existing technology 1:

[0007] Chinese patent application CN103721550A discloses an absorbent for simultaneous desulfurization, denitrification, and VOC removal of flue gas, its preparation, and application. The absorbent is composed of the following components by mass percentage: 5-10% ammonium salt, 0.01-0.50% surfactant, 1‰-2% complexing agent, and water as the balance. The absorbent provided in this prior art can simultaneously and efficiently purify dust, SO2, and NO in flue gas within a single system. x It can remove multiple pollutants such as VOCs, and has the advantages of high pollutant removal efficiency, simple process equipment, small footprint, low investment and operating costs, and easy system control and management. In addition, the raw materials of the absorbent are readily available, inexpensive, simple and safe to transport, store, prepare and use, and have low production costs.

[0008] Disadvantages of existing technology 1:

[0009] While the existing technology has many advantages as described above, it generates new wastewater and waste residue during the pollutant removal process.

[0010] Prior art related to this invention:

[0011] Technical solution of existing technology 2:

[0012] Chinese patent application CN105617858A discloses a combined multi-pollutant synergistic deep purification device and process for flue gas. The device consists of a low-temperature SCR pretreatment tower, a low-temperature SCR denitrification reactor, and a wet absorption tower, among other components. The process is implemented using this device. The low-temperature SCR denitrification reactor and the wet absorption tower have a synergistic effect, achieving synergistic deep purification of multiple pollutants, resulting in an SO2 purification rate greater than 95% and NO... x The purification rate for heavy metals, fluorides, and chlorides can exceed 95%, and all pollutants can meet the requirements of the new emission standards. Furthermore, the process is simple and compact, with low investment and operating costs, stable and reliable operation, and no secondary pollution. It is applicable to various industrial kilns such as glass kilns, ceramic kilns, metal smelting furnaces, and aluminum profile melting furnaces.

[0013] Disadvantages of existing technology 2:

[0014] While the second prior art has many advantages as described above, it requires multiple reactors connected in series to control a variety of pollutants, making the system complex.

[0015] Therefore, providing a novel combustion flue gas full-load catalytic reduction-oxidation coupled reaction device and process has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0016] In response to the presence of various air pollutants such as NOx, heavy metals (e.g., Hg), dioxins, and volatile organic compounds (VOCs) in the flue gas from the steel industry, this invention develops a catalytic reduction-oxidation coupled reaction device and process, which can achieve integrated and synergistic control of multiple pollutants under full load conditions.

[0017] To this end, on the one hand, the present invention provides a full-load catalytic reduction-oxidation coupling reaction device for combustion flue gas, wherein the full-load catalytic reduction-oxidation coupling reaction device for combustion flue gas includes: a reduction-oxidation coupling reactor and an inlet flue disposed at the inlet of the reduction-oxidation coupling reactor, wherein three sets of guide plates are disposed in the inlet flue along the flow direction of combustion flue gas, and 3-4 layers of catalyst modules are disposed in the reduction-oxidation coupling reactor along the flow direction of combustion flue gas.

[0018] The inlet flue includes an incoming flue and an outgoing flue, as well as a deflection bend between the incoming and outgoing flues. Three sets of guide plates are respectively installed in the incoming flue, at the deflection bend, and in the outgoing flue. The second and third sets of guide plates are telescopic guide plates, which can be retracted or extended according to the load of the combustion flue gas source equipment.

[0019] In this invention, the combustion flue gas source equipment includes conventional equipment such as boilers and sintering machines. The load conditions of the combustion flue gas source equipment can be obtained through conventional methods in the art.

[0020] As a specific embodiment of the combustion flue gas full-load catalytic reduction oxidation coupling reaction device of the present invention, each catalyst module is a honeycomb catalyst with a thickness of 800-1500mm, a pitch of 7-10mm, a wall thickness of 0.8-1.6mm, and a single catalyst module pore size of 16×16-25×25mm.

[0021] As a specific embodiment of the combustion flue gas full-load catalytic reduction oxidation coupled reaction device of the present invention, the first 2-3 catalyst modules are catalyst modules with active components arranged in layers, including a surface layer and an inner layer respectively. The surface layer is a selective catalytic reduction catalyst layer, which plays the role of selective catalytic reduction, and the inner layer is a catalytic oxidation catalyst layer, which plays the role of catalytic oxidation.

[0022] The final catalyst module is an oxidizing catalyst layer.

[0023] As a specific embodiment of the combustion flue gas full-load catalytic reduction-oxidation coupled reaction device of the present invention, the 3-4 catalyst modules are catalyst modules with active components arranged in layers, each including a surface layer and an inner layer, wherein the surface layer is a selective catalytic reduction catalyst layer and the inner layer is a catalytic oxidation catalyst layer.

[0024] As a specific embodiment of the combustion flue gas full-load catalytic reduction-oxidation coupled reaction device of the present invention, the active component layer thickness in the selective catalytic reduction catalyst layer is 0.05-0.15 mm, the active component layer thickness in the catalytic oxidation catalyst layer is 0.1-0.2 mm, and the active component layer thickness in the oxidizing catalyst layer is 0.15-0.35 mm.

[0025] As a specific embodiment of the combustion flue gas full-load catalytic reduction-oxidation coupled reaction device of the present invention, the active component of the selective catalytic reduction catalyst layer includes one or a combination of several metal oxides such as V2O5, WO3, TiO2, MoO3, Al2O3, ZrO2, and Fe2O3, and the active component of the catalytic oxidation catalyst layer includes CoOx CeO2, CuO, MnO x One or more of metal oxides such as Al2O3, wherein the active component of the oxidized catalyst layer includes CoO x CeO2, CuO, MnO x One or more of metal oxides such as Al2O3.

[0026] As a specific embodiment of the combustion flue gas full-load catalytic reduction oxidation coupling reaction device of the present invention, the catalysts used in the first 2-3 catalyst modules are all commercially available SCR catalysts that can be obtained conventionally.

[0027] In this invention, the catalysts used in each catalyst module include an active component and a support, with the active component loaded on the support.

[0028] As a specific embodiment of the combustion flue gas full-load catalytic reduction oxidation coupling reaction device of the present invention, the carrier includes one or a combination of several of TiO2, Al2O3, ZrO2, SiO2, etc.

[0029] As a specific embodiment of the combustion flue gas full-load catalytic reduction oxidation coupling reaction device of the present invention, the incoming flue is a 90° bend that turns from vertical to horizontal, the first set of guide plates is arranged sequentially along the direction from the inner corner to the outer corner of the incoming flue, and the first set of guide plates is an arc-shaped guide plate, with the spacing and bending radius of each arc-shaped guide plate increasing sequentially.

[0030] As a specific embodiment of the combustion flue gas full-load catalytic reduction oxidation coupling reaction device of the present invention, any one of the first group of guide plates is fixed to a rotatable support rod by a connecting plate, so as to adjust the tilt angle of the guide plate by rotating the rotatable support rod.

[0031] As a specific embodiment of the combustion flue gas full-load catalytic reduction oxidation coupling reaction device of the present invention, the adjustment range of the tilt angle is -10° to 10° based on the initial tilt angle of the guide plate.

[0032] In this invention, the initial tilt angle is the angle between the axis of symmetry of the guide vane and the horizontal plane. Furthermore, this invention does not impose specific requirements on the initial tilt angle of the guide vane, which can be reasonably set according to the actual situation on site.

[0033] In this invention, the tilt angles of each guide vane in the first group of guide vanes can be the same or different, and preferably all guide vanes in the first group of guide vanes have the same tilt angle.

[0034] As a specific embodiment of the combustion flue gas full-load catalytic reduction oxidation coupling reaction device of the present invention, the top flue wall of the deflection bend and the outflow flue is inclined, and the second set of guide plates is arranged sequentially along the direction from the top flue wall of the deflection bend to the inner corner of the deflection bend and in a manner parallel to the top flue wall. The second set of guide plates is a flat plate, and the length of each flat plate increases sequentially.

[0035] As a specific embodiment of the combustion flue gas full-load catalytic reduction oxidation coupling reaction device of the present invention, the second set of guide plates includes a telescopic rod, a movable support rod and a flat guide plate. One end of the telescopic rod is fixed to the top flue wall at the deflection bend, and the other end is alternately provided with the movable support rod and the flat guide plate, and the movable support rod is symmetrically arranged along the telescopic rod.

[0036] As a specific embodiment of the combustion flue gas full-load catalytic reduction oxidation coupling reaction device of the present invention, the third group of guide plates is arranged sequentially along the direction from the inner corner of the deflection bend to the flue wall of the outflow flue (the flue wall in the direction opposite to the inner corner of the deflection bend, and can be the top flue wall or the vertical part of the flue wall), and the third group of guide plates is an arc-shaped guide plate, and the bending radius of each arc-shaped guide plate is the same and the same as the bending radius of the inner corner of the deflection bend.

[0037] As a specific embodiment of the combustion flue gas full-load catalytic reduction oxidation coupling reaction device of the present invention, the third set of guide plates includes a telescopic rod, a movable support rod and an arc-shaped guide plate. One end of the telescopic rod is fixed to the flue wall corresponding to the inner corner of the deflection bend, and the other end is alternately provided with the movable support rod and the arc-shaped guide plate, and the movable support rod is symmetrically arranged along the telescopic rod.

[0038] On the other hand, the present invention also provides a full-load catalytic reduction-oxidation coupled reaction process for combustion flue gas, wherein the full-load catalytic reduction-oxidation coupled reaction process for combustion flue gas includes:

[0039] When the load of the combustion flue gas source equipment is less than 35%, the second and third sets of guide plates are retracted, allowing the combustion flue gas to enter the reduction-oxidation coupling reactor through the first set of guide plates and remove pollutants therein;

[0040] When the load of the combustion flue gas source equipment is 35-60%, the second set of guide plates is retracted and the third set of guide plates is deployed, so that the combustion flue gas enters the reduction-oxidation coupling reactor in sequence through the first set of guide plates and the third set of guide plates and removes the pollutants therein;

[0041] When the load of the combustion flue gas source equipment is >60%, the second and third sets of guide plates are deployed so that the combustion flue gas passes through the first, second and third sets of guide plates in sequence into the reduction-oxidation coupling reactor and removes the pollutants therein;

[0042] Alternatively, the full-load catalytic reduction-oxidation coupling reaction process for combustion flue gas may further include:

[0043] The second and third sets of guide vanes are deployed so that the combustion flue gas passes through the first, second, and third sets of guide vanes in sequence into the reduction-oxidation coupling reactor to remove pollutants. In other words, the guide vane group is not adjusted according to the load of the combustion flue gas source equipment. Instead, for combustion flue gas under any load, it is allowed to pass through the first, second, and third sets of guide vanes in sequence into the reduction-oxidation coupling reactor to remove pollutants.

[0044] In this invention, the retraction and deployment of the guide vane assembly need to be adjusted according to the real-time monitoring results of the load of the combustion flue gas source equipment. For example, in some embodiments of this invention, the initial load of the combustion flue gas source equipment is 20%, which is <35%. At this time, the second and third sets of guide vanes are retracted, allowing the combustion flue gas to enter the reduction-oxidation coupling reactor through the first set of guide vanes and remove pollutants therein. Subsequently, the load of the combustion flue gas source equipment increases to 50%, which is in the range of 35-60%. At this time, the second set of guide vanes is retracted and the third set of guide vanes is deployed, allowing the combustion flue gas to enter the reduction-oxidation coupling reactor sequentially through the first and third sets of guide vanes and remove pollutants therein. Finally, the load of the combustion flue gas source equipment increases to 80%, which is >60%. At this time, the second and third sets of guide vanes are deployed, allowing the combustion flue gas to enter the reduction-oxidation coupling reactor sequentially through the first, second, and third sets of guide vanes and remove pollutants therein.

[0045] In other embodiments of the present invention, the initial load of the combustion flue gas source device is 55%, which is in the range of 35-60%. At this time, the second set of guide plates is retracted and the third set of guide plates is deployed, so that the combustion flue gas enters the reduction-oxidation coupling reactor in sequence through the first set of guide plates and the third set of guide plates and removes the pollutants therein. Subsequently, the load of the combustion flue gas source device is increased to 90%, which is >60%. At this time, the second set of guide plates and the third set of guide plates are deployed, so that the combustion flue gas enters the reduction-oxidation coupling reactor in sequence through the first set of guide plates, the second set of guide plates and the third set of guide plates and removes the pollutants therein.

[0046] In some other embodiments of the present invention, the initial load of the combustion flue gas source device is 95%, which is >60%. At this time, the second set of guide plates and the third set of guide plates are deployed so that the combustion flue gas passes through the first set of guide plates, the second set of guide plates and the third set of guide plates in sequence into the reduction-oxidation coupling reactor and removes the pollutants therein.

[0047] As a specific embodiment of the process described above in this invention, the reaction temperature range for the pollutant removal process in the reduction-oxidation coupled reactor is 200-450℃.

[0048] As a specific embodiment of the process described above in this invention, the process further includes: adjusting the inclination angle of each guide plate in the first group of guide plates according to the load condition of the combustion flue gas source equipment, wherein the adjustment process includes:

[0049] When the load of the combustion flue gas source equipment is <35%, the adjustment range of the tilt angle is -10° to 0° based on the initial tilt angle of the guide plate.

[0050] When the load of the combustion flue gas source equipment is 35-60%, the adjustment range of the tilt angle is -5° to 5° based on the initial tilt angle of the guide plate.

[0051] When the load of the combustion flue gas source equipment is >60%, the tilt angle can be adjusted from 0° to 10° based on the initial tilt angle of the guide plate.

[0052] In this invention, after the combustion flue gas enters the reduction-oxidation coupled reactor, NOx in the flue gas undergoes a selective catalytic reduction (SCR) reaction with the reducing agent ammonia on the surface of the first 2-3 catalyst modules, generating harmless nitrogen and water. Excess reducing agent ammonia and VOCs diffuse into the inner layers of the first 2-3 catalyst modules. Under the action of the catalytic oxidation catalyst, NH3 is selectively oxidized into harmless nitrogen and water, and VOCs are oxidized into CO2 and water. Heavy metals (such as Hg) and dioxins in the combustion flue gas are oxidized into easily absorbed high-valence heavy metals and harmless small molecules, respectively, under the action of the oxidizing catalyst in the last catalyst module. The treated clean flue gas is discharged from the outlet of the reduction-oxidation coupled reactor. This invention uses catalyst modules with layered active components in the reduction-oxidation coupled reactor, allowing different pollutants to react in different bulk phase layers based on the different relationships between the reaction rates and mass transfer rates of different pollutant molecules contained in the combustion flue gas within the catalyst bulk phase.

[0053] Compared with the prior art, the beneficial technical effects achieved by the present invention include:

[0054] This invention achieves the coupling of selective catalytic reduction and catalytic oxidation by simultaneously setting up a catalyst module with active components arranged in layers and an oxidizing catalyst layer. Furthermore, it achieves the simultaneous reduction and oxidation of NOx and Hg within the same reduction-oxidation coupled reactor. 0 This invention achieves efficient and synergistic removal of multiple pollutants such as dioxins and VOCs. Furthermore, as the workload of the upstream equipment, i.e., the combustion flue gas source equipment, changes cause fluctuations in flue gas flow rate and temperature. To address this, the invention retracts or deploys the corresponding guide plate assembly according to the load conditions of the combustion flue gas source equipment. This is equivalent to adjusting the angle of the guide plates in the guide plate assembly, resulting in a more uniform velocity, pressure, and concentration field across the cross-section of the reduction-oxidation coupled reactor, thereby ensuring stable operation of the device under full load conditions. Attached Figure Description

[0055] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0056] Figure 1 This is a schematic diagram of the structure of the combustion flue gas full-load catalytic reduction oxidation coupling reaction device provided in Embodiment 1 of the present invention.

[0057] Figure 2 This is a schematic diagram of the catalyst structure used in the first and second catalyst modules in Embodiment 1 of the present invention.

[0058] Figure 3 The following is a schematic diagram illustrating the positional relationship of the second-layer catalyst module in the reduction-oxidation coupling reactor and the structure of the catalyst used therein, using the second-layer catalyst module as an example in Embodiment 1 of the present invention.

[0059] Figure 4 This is a schematic diagram of the inlet flue in Embodiment 1 of the present invention.

[0060] Figure 5 This is a schematic diagram of the structure of any one of the guide plates in the first group of guide plates in Embodiment 1 of the present invention.

[0061] Figure 6 This is a schematic diagram of the structure of the second set of guide plates in Embodiment 1 of the present invention.

[0062] Figure 7a This is a schematic diagram showing the arrangement of the guide plate in Embodiment 2 of the present invention when the load of the combustion flue gas source equipment is <35%.

[0063] Figure 7bThis is a schematic diagram showing the arrangement of the guide plate in Embodiment 2 of the present invention when the load of the combustion flue gas source device is 35-60%.

[0064] Figure 7c This is a schematic diagram showing the arrangement of the guide plate in Embodiment 2 of the present invention when the load of the combustion flue gas source device is >60%.

[0065] Explanation of main icon numbers:

[0066] 1. Reduction-oxidation coupled reactor;

[0067] 11. First-layer catalyst module;

[0068] 12. Second-layer catalyst module;

[0069] 111 / 121, Surface layer;

[0070] 112 / 122, Inner layer;

[0071] 113 / 123, Carrier;

[0072] 13. Third-layer catalyst module;

[0073] 2. Inlet flue;

[0074] 21. First set of deflectors;

[0075] 211. Connecting plate;

[0076] 212. Rotatable support rod;

[0077] 213. Arc-shaped air deflector;

[0078] 22. Second set of deflectors;

[0079] 221. Telescopic pole;

[0080] 222. Movable support rod;

[0081] 223. Flat-plate air deflector;

[0082] 23. The third set of deflectors;

[0083] 3. Top flue wall;

[0084] Ⅰ. Incoming flue;

[0085] II. Deflection and turning;

[0086] III. Exit the flue. Detailed Implementation

[0087] It should be noted that the term "comprising" and any variations thereof in the specification, claims, and accompanying drawings of this invention are intended to cover non-exclusive inclusion. For example, a process, method / process, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods / processes, products, or devices.

[0088] In this invention, the terms "upper," "lower," "inner," "outer," and "middle," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing the invention and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0089] Furthermore, in addition to indicating direction or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in certain situations to indicate a dependency or connection. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0090] Furthermore, the terms "setup" and "connection" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0091] The "range" disclosed in this invention is given in the form of a lower limit and an upper limit. It can be one or more lower limits and one or more upper limits, respectively. A given range is defined by selecting a lower limit and an upper limit. The selected lower and upper limits define the boundaries of the particular range. All ranges defined in this way are composable, meaning that any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for specific parameters, it is also expected that ranges of 60-110 and 80-120 are also expected. Furthermore, if the listed minimum range values ​​are 1 and 2, and the listed maximum range values ​​are 3, 4, and 5, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5.

[0092] In this invention, unless otherwise specified, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this invention, and "0-5" is simply a shortened representation of these numerical combinations.

[0093] In this invention, unless otherwise specified, all embodiments and preferred embodiments mentioned in this invention can be combined with each other to form new technical solutions.

[0094] In this invention, unless otherwise specified, all technical features and preferred features mentioned in this invention can be combined with each other to form new technical solutions.

[0095] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying tables, drawings, and embodiments. The embodiments described below are some, but not all, embodiments of this invention, and are only used to illustrate the invention, and should not be considered as limiting the scope of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0096] Example 1

[0097] This embodiment provides a full-load catalytic reduction-oxidation coupled reaction device for combustion flue gas, wherein a schematic diagram of the structure of the full-load catalytic reduction-oxidation coupled reaction device for combustion flue gas is shown below. Figure 1 As shown, from Figure 1 As can be seen from the diagram, it includes: a reduction-oxidation coupled reactor 1 and an inlet flue 2 welded to the inlet of the reduction-oxidation coupled reactor 1. A flow straightening grid is also provided at the junction of the reduction-oxidation coupled reactor 1 and the inlet flue 2. Figure 1 (Not shown in the image), three sets of guide plates are arranged in the inlet flue 2 along the flow direction of the combustion flue gas, namely the first set of guide plates 21, the second set of guide plates 22 and the third set of guide plates 23. Three layers of catalyst modules are arranged in the reduction-oxidation coupling reactor 1 along the flow direction of the combustion flue gas, namely the first layer of catalyst module 11, the second layer of catalyst module 12 and the third layer of catalyst module 13. Each catalyst module is a honeycomb catalyst, each catalyst bed is 1200mm thick, the pitch is 9mm, the wall thickness is 1.2mm, and the hole size of a single catalyst module is 20×20mm.

[0098] The structural diagrams of the catalysts used in the first catalyst module 11 and the second catalyst module 12 are shown below. Figure 2 and Figure 3 As shown, from Figure 2 and Figure 3 As can be seen, both the first catalyst module 11 and the second catalyst module 12 include a surface layer 111 / 121 and an inner layer 112 / 122. The surface layer 111 / 121 is a selective catalytic reduction catalyst layer, with active components containing V2O5, WO3, and TiO2. The active components are supported on a support 113 / 123, whose main components are TiO2 and SiO2. The thickness of the active component layer is 0.1 mm. The inner layer 112 / 122 is a catalytic oxidation catalyst layer, with active components containing CoO2. x The active components, namely TiO2 and CuO, are loaded on a support 113 / 123, the main components of which are TiO2 and SiO2, and the thickness of the active component layer is 0.1 mm.

[0099] The third catalyst module 13 is an oxidation catalyst layer, and its active components mainly contain CoO. x CeO2 and MnO are active components loaded on a support, the main components of which are Al2O3 and ZrO2, and the thickness of the active component layer is 0.2 mm.

[0100] The structural schematic diagram of the inlet flue 2 is shown below. Figure 4 As shown, from Figure 4 As can be seen from the diagram, it includes an incoming flue I and an outgoing flue III, as well as a deflection bend II located between the incoming flue I and the outgoing flue III. The first set of guide plates 21, the second set of guide plates 22, and the third set of guide plates 23 are respectively located in the incoming flue I, at the deflection bend II, and in the outgoing flue III. The second set of guide plates 22 and the third set of guide plates 23 are both telescopic guide plates, which can be retracted or extended according to the load of the combustion flue gas source equipment.

[0101] Specifically, the incoming flue I is a 90° bend that turns from vertical to horizontal, and the first set of guide plates 21 are along the inner corner of the incoming flue I (i.e. Figure 4 Chinese r n From the outer corner (i.e.) Figure 4 Chinese r w The guide plates are arranged sequentially in the direction of the flow path (at the location), and the guide plates in the first group of guide plates 21 are arc-shaped guide plates. The bending direction of each arc-shaped guide plate is the same as the bending direction of the inner and outer corners of the incoming flue I. The spacing between each arc-shaped guide plate increases sequentially in the form of an arithmetic sequence and r. n The bending radius and r of each arc-shaped guide vane w They also increase sequentially in the form of an arithmetic sequence;

[0102] The structural schematic diagram of any arc-shaped guide vane in the first group of guide vanes 21 is shown below. Figure 5 As shown, from Figure 5 As can be seen, any arc-shaped guide plate 213 is fixed to a rotatable support rod 212 via a connecting plate 211, so that the tilt angle of the arc-shaped guide plate 213 can be adjusted by rotating the rotatable support rod 212. Based on the initial tilt angle of the arc-shaped guide plate 213, the adjustment range of the tilt angle is -10° to 10°.

[0103] In this embodiment, the initial tilt angle of any arc-shaped guide vane 213 (e.g., Figure 4 The initial tilt angle shown is 45°, and the adjusted tilt angle is the same.

[0104] The number of arc-shaped guide vanes in the first group of guide vanes 21 is calculated according to the following formula 1):

[0105] n≈2S / (r w +r n ) Formula 1);

[0106] In Formula 1), n ​​is the number of arc-shaped guide vanes in the first group of guide vanes 21, in units of one;

[0107] r w The radius of curvature of the outer corner of the incoming flue is measured in mm.

[0108] r n The radius of curvature of the inner corner of the incoming flue is in mm;

[0109] S is the vertical distance between the inner and outer corners of the incoming flue, in mm;

[0110] Among them, the spacing of each arc-shaped guide vane, the S value, and the r value are... n The bending radius and r of each arc-shaped guide vane w These parameters all need to be determined based on the actual flue dimensions; such as Figure 4 As shown, in this embodiment, the number of arc-shaped guide vanes in the first group of guide vanes 21 is 3;

[0111] The top flue wall at the deflection bend II and the outflow flue III is inclined. The second group of guide plates 22 are arranged sequentially along the direction from the top flue wall at the deflection bend II to the inner corner of the deflection bend II, and in a manner parallel to the top flue wall. The guide plates in the second group of guide plates 22 are flat plate guide plates, and the length of each flat plate guide plate increases sequentially. In this embodiment, there are 3 flat plate guide plates, and the spacing between each flat plate guide plate is the same. The lengths of each flat plate guide plate (from the outside to the inside) are 700mm, 500mm and 300mm respectively. The spacing between each flat plate guide plate needs to be determined according to the actual flue size.

[0112] In this embodiment, the structural schematic diagram of the second group of guide vanes 22 is as follows: Figure 6 As shown, from Figure 6 As can be seen from the diagram, it includes a telescopic rod 221, a movable support rod 222, and a flat guide plate 223. One end of the telescopic rod 221 is fixed to the top flue wall 3 at the bend, and the other end is alternately provided with the movable support rod 222 and the flat guide plate 223. The movable support rod 222 is symmetrically arranged along the telescopic rod 221 so that the second set of guide plates 22 can be retracted or extended according to the load of the combustion flue gas source equipment.

[0113] The third set of guide vanes 23 runs along the inner corner of the deflection bend II (i.e.) Figure 4 Chinese r m The guide plates in the third group 23 are arranged sequentially along the flue wall direction opposite to the inner corner of the deflection bend (II) to the outflow flue III. The guide plates in the third group 23 are arc-shaped guide plates with the same spacing. The bending direction of each arc-shaped guide plate is the same as the bending direction of the inner corner of the deflection bend (II), and the bending radius of the arc-shaped guide plates is the same as that of the inner corner of the deflection bend (r). m same;

[0114] The number of arc-shaped guide vanes in the third group of guide vanes 23 is calculated according to the following formula 2):

[0115] N = S' / r m Formula 2);

[0116] In Formula 2), N is the number of arc-shaped guide vanes in the third group of guide vanes 23, in units of one;

[0117] S' is the diameter of the inlet of the reduction-oxidation coupled reactor 1, in mm;

[0118] r m The radius of curvature of the inner angle at deflection bend II is in mm;

[0119] Among them, the spacing, S' value, and r of each arc-shaped guide plate in the third group of guide plates 23 m These parameters all need to be determined based on the actual flue dimensions; such as Figure 4 As shown, in this embodiment, the number of arc-shaped guide vanes in the third group of guide vanes 23 is 8;

[0120] In this embodiment, the structure of the third set of guide plates 23 is basically the same as that of the second set of guide plates 22. It includes a telescopic rod, a movable support rod, and an arc-shaped guide plate. One end of the telescopic rod is fixed to the flue wall corresponding to the inner corner of the deflection bend, and the other end is alternately provided with a movable support rod and the arc-shaped guide plate. The movable support rod is symmetrically arranged along the telescopic rod so that the third set of guide plates 23 can be retracted or unfolded according to the load of the combustion flue gas source equipment.

[0121] Comparative Example 1

[0122] This comparative example provides a catalytic reduction-oxidation coupled reaction device for combustion flue gas, which differs from the full-load catalytic reduction-oxidation coupled reaction device for combustion flue gas provided in Example 1 only in that:

[0123] 1) The catalysts used in the first, second and third catalyst modules are all existing conventional commercial SCR catalysts, with the main components being V2O5-WO3 / TiO2;

[0124] 2) Only the first set of guide vanes is set, and the second and third sets of guide vanes are not set. That is, the corresponding guide vane groups are not retracted or deployed according to the load of the combustion flue gas source equipment.

[0125] Example 2

[0126] This embodiment provides a full-load catalytic reduction-oxidation coupled reaction process for combustion flue gas, which is implemented using the full-load catalytic reduction-oxidation coupled reaction device for combustion flue gas provided in Embodiment 1. The process includes the following specific steps:

[0127] When the load on the combustion flue gas source equipment is less than 35%, retract the second and third sets of guide vanes, respectively. Figure 4 The diagram shows the configuration of the air deflector at positions i and ii. Figure 7a As shown, the combustion flue gas is passed through the first set of guide plates into the reduction-oxidation coupling reactor, where pollutants are removed.

[0128] When the load of the combustion flue gas source equipment is 35-60%, retract the second set of guide vanes and store them in place. Figure 4 At position i shown in the diagram, the third set of guide vanes is deployed. The arrangement of the guide vanes at this time is illustrated in the diagram below. Figure 7bAs shown, the combustion flue gas is sequentially passed through the first set of guide plates and the third set of guide plates into the reduction-oxidation coupling reactor, where pollutants are removed;

[0129] When the load of the combustion flue gas source equipment is >60%, the second and third sets of guide vanes are deployed. The schematic diagram of the guide vane setup at this time is shown below. Figure 7c As shown, the combustion flue gas is sequentially passed through the first set of guide plates, the second set of guide plates and the third set of guide plates into the reduction-oxidation coupling reactor to remove pollutants. The treated clean flue gas is discharged from the outlet of the reduction-oxidation coupling reactor.

[0130] In the reduction-oxidation coupled reactor, the reaction temperature range for the pollutant removal process is 200-450℃.

[0131] In this embodiment, the tilt angle of each guide vane in the first group of guide vanes can also be adjusted according to the load of the combustion flue gas source equipment. The adjustment process includes:

[0132] When the load of the combustion flue gas source equipment is <35%, the adjustment range of the tilt angle is -10° to 0° based on the initial tilt angle of the guide plate.

[0133] When the load of the combustion flue gas source equipment is 35-60%, the adjustment range of the tilt angle is -5° to 5° based on the initial tilt angle of the guide plate.

[0134] When the load of the combustion flue gas source equipment is >60%, the tilt angle can be adjusted from 0° to 10° based on the initial tilt angle of the guide plate.

[0135] Comparative Example 2

[0136] This comparative example provides a catalytic reduction-oxidation coupled reaction process for combustion flue gas, which is implemented using the catalytic reduction-oxidation coupled reaction device for combustion flue gas provided in Comparative Example 1. The process includes the following specific steps:

[0137] The combustion flue gas is passed through the first set of guide plates into the reduction-oxidation coupling reactor to remove pollutants. The treated clean flue gas is discharged from the outlet of the reduction-oxidation coupling reactor.

[0138] In Embodiment 2 and Comparative Example 2 of the present invention, the velocity field, pressure field and concentration field distribution of the cross section of the reduction-oxidation coupling reactor are shown in Table 1 below, and the pollutant removal status is shown in Table 2 below.

[0139] Table 1 shows the flow field distribution in Example 2 and Comparative Example 2.

[0140]

[0141] Table 2. Pollutant removal status in Example 2 and Comparative Example 2

[0142]

[0143] As can be seen from Table 1 above, compared with Comparative Example 2, the velocity deviation, temperature deviation and concentration deviation under the three load conditions in Example 2 are significantly reduced, and the decreasing trend is more obvious under low load conditions. Specifically, under low load conditions, i.e., when the load is <35%, the flue gas velocity distribution deviation is reduced by about half, the flue gas temperature distribution deviation is reduced by nearly two times, and the flue gas concentration distribution deviation is also reduced by about half.

[0144] As can be seen from Table 2 above, compared with Comparative Example 2, the denitrification efficiency and VOCs removal efficiency under the three load conditions in Example 2 are significantly increased, while ammonia slip is significantly reduced. When the load is >60%, the denitrification efficiency and Hg in Example 2 are significantly reduced. 0 The removal efficiency of various pollutants such as dioxins and VOCs is over 90%.

[0145] In summary, the embodiments of the present invention achieve the coupling of selective catalytic reduction and catalytic oxidation by simultaneously setting up a catalyst module with active components arranged in layers and an oxidizing catalyst layer, and achieve the simultaneous reduction and oxidation of NOx and Hg within the same reduction-oxidation coupled reactor. 0 This invention achieves efficient and synergistic removal of multiple pollutants such as dioxins and VOCs. Furthermore, as the workload of the upstream equipment, i.e., the combustion flue gas source equipment, changes cause fluctuations in flue gas flow rate and temperature. To address this, this embodiment of the invention retracts or expands the corresponding guide plate assembly according to the load of the combustion flue gas source equipment. This is equivalent to adjusting the angle of the guide plates in the guide plate assembly, resulting in a more uniform velocity, pressure, and concentration field across the cross-section of the reduction-oxidation coupled reactor, thereby ensuring stable operation of the device under full load conditions.

[0146] The above description is merely a specific embodiment of the present invention and should not be construed as limiting the scope of the invention. Therefore, any substitution of equivalent components or equivalent changes and modifications made within the scope of protection of this patent should still fall within the scope of this patent. Furthermore, the technical features, technical features and technical inventions, and technical inventions in this invention can be freely combined and used.

Claims

1. A full-load catalytic reduction-oxidation coupled reaction device for combustion flue gas, characterized in that, The full-load catalytic reduction-oxidation coupling reaction device for combustion flue gas includes: a reduction-oxidation coupling reactor and an inlet flue located at the inlet of the reduction-oxidation coupling reactor. Three sets of guide plates are arranged in the inlet flue along the flow direction of the combustion flue gas. Three to four layers of catalyst modules are arranged in the reduction-oxidation coupling reactor along the flow direction of the combustion flue gas. The first two to three layers of catalyst modules each include a surface layer and an inner layer, wherein the surface layer is a selective catalytic reduction catalyst layer and the inner layer is a catalytic oxidation catalyst layer. The last catalyst module is an oxidizing catalyst layer; Alternatively, a 3-4 layer catalyst module may include a surface layer and an inner layer, wherein the surface layer is a selective catalytic reduction catalyst layer and the inner layer is a catalytic oxidation catalyst layer; The inlet flue includes an incoming flue and an outgoing flue, as well as a deflection bend between the incoming and outgoing flues. Three sets of guide plates are respectively installed in the incoming flue, at the deflection bend, and in the outgoing flue. The second and third sets of guide plates are telescopic guide plates, which can be retracted or extended according to the load of the combustion flue gas source equipment. The incoming flue is a 90° bend that turns from vertical to horizontal. The first set of guide plates is arranged sequentially along the direction from the inner corner to the outer corner of the incoming flue, and the first set of guide plates is an arc-shaped guide plate. The spacing and bending radius of each arc-shaped guide plate increase sequentially. Each guide plate in the first set of guide plates is fixed to a rotatable support rod by a connecting plate, so that the tilt angle of the guide plate can be adjusted by rotating the rotatable support rod. The top flue wall at the deflection bend and the outflow flue is inclined. The second set of guide plates is arranged sequentially along the direction from the top flue wall at the deflection bend to the inner corner of the deflection bend, and in a manner parallel to the top flue wall. The second set of guide plates is a flat plate, and the length of each flat plate increases sequentially. The second set of guide plates includes a telescopic rod, a movable support rod, and a flat plate. One end of the telescopic rod is fixed to the top flue wall at the deflection bend, and the other end is alternately provided with a movable support rod and the flat plate. The movable support rod is symmetrically arranged along the telescopic rod. The third set of guide vanes is arranged sequentially along the direction from the inner corner of the deflection bend to the flue wall of the outflow flue. The third set of guide vanes are arc-shaped guide vanes, and the bending radius of each arc-shaped guide vane is the same as that of the inner corner of the deflection bend.

2. The combustion flue gas full-load catalytic reduction-oxidation coupled reaction device according to claim 1, characterized in that, Each catalyst module is a honeycomb catalyst with a thickness of 800-1500mm, a pitch of 7-10mm, a wall thickness of 0.8-1.6mm, and a single catalyst module pore size of 16×16-25×25 mm.

3. The combustion flue gas full-load catalytic reduction-oxidation coupled reaction device according to claim 1, characterized in that, The active component layer in the selective catalytic reduction catalyst layer has a thickness of 0.05-0.15 mm, the active component layer in the catalytic oxidation catalyst layer has a thickness of 0.1-0.2 mm, and the active component layer in the oxidizing catalyst layer has a thickness of 0.15-0.35 mm.

4. The combustion flue gas full-load catalytic reduction-oxidation coupled reaction device according to claim 1 or 3, characterized in that, The active components of the selective catalytic reduction catalyst layer include one or a combination of several of V₂O₅, WO₃, TiO₂, MoO₃, Al₂O₃, ZrO₂, and Fe₂O₃; the active components of the catalytic oxidation catalyst layer include CoO₂. x CeO2, CuO, MnO x One or more of Al2O3, wherein the active component of the oxidized catalyst layer includes CoO x CeO2, CuO, MnO x One or more of Al2O3.

5. The combustion flue gas full-load catalytic reduction-oxidation coupled reaction device according to claim 1, characterized in that, Based on the initial tilt angle of the guide vane, the tilt angle can be adjusted within the range of -10° to 10°.

6. The combustion flue gas full-load catalytic reduction-oxidation coupled reaction device according to claim 1, characterized in that, The third set of guide plates includes a telescopic rod, a movable support rod, and an arc-shaped guide plate. One end of the telescopic rod is fixed to the flue wall corresponding to the inner corner of the deflection bend, and the other end is alternately provided with a movable support rod and the arc-shaped guide plate, and the movable support rod is symmetrically arranged along the telescopic rod.

7. A full-load catalytic reduction-oxidation coupled reaction process for combustion flue gas, characterized in that, The full-load catalytic reduction-oxidation coupling reaction process for combustion flue gas is implemented using the full-load catalytic reduction-oxidation coupling reaction device for combustion flue gas according to any one of claims 1-6, including cases where the guide vane assembly is not adjusted or cases where the guide vane assembly is adjusted according to the load of the combustion flue gas source equipment: Specifically, when adjusting the guide vane assembly according to the load of the combustion flue gas source equipment, the process includes: When the load of the combustion flue gas source equipment is less than 35%, the second and third sets of guide plates are retracted, allowing the combustion flue gas to enter the reduction-oxidation coupling reactor through the first set of guide plates and remove pollutants therein; When the load of the combustion flue gas source equipment is 35-60%, the second set of guide plates is retracted and the third set of guide plates is deployed, so that the combustion flue gas enters the reduction-oxidation coupling reactor through the first set of guide plates and the third set of guide plates in sequence and removes the pollutants therein; When the load of the combustion flue gas source equipment is >60%, the second and third sets of guide plates are deployed so that the combustion flue gas passes through the first, second and third sets of guide plates in sequence into the reduction-oxidation coupling reactor and removes the pollutants therein; When the guide vane assembly is not adjusted, the process specifically includes: The second and third sets of guide vanes are deployed so that the combustion flue gas passes through the first, second, and third sets of guide vanes in sequence into the reduction-oxidation coupling reactor, where pollutants are removed.

8. The process according to claim 7, characterized in that, In the reduction-oxidation coupled reactor, the reaction temperature range for the pollutant removal process is 200-450℃.

9. The process according to claim 7 or 8, characterized in that, When adjusting the guide vane assembly according to the load condition of the combustion flue gas source equipment, the process further includes: adjusting the inclination angle of each guide vane in the first group of guide vanes according to the load condition of the combustion flue gas source equipment, wherein the adjustment process includes: When the load of the combustion flue gas source equipment is less than 35%, the adjustment range of the tilt angle is -10° to 0° based on the initial tilt angle of the guide plate. When the load of the combustion flue gas source equipment is 35-60%, the adjustment range of the tilt angle is -5° to 5° based on the initial tilt angle of the guide plate. When the load of the combustion flue gas source equipment is >60%, the tilt angle can be adjusted from 0° to 10° based on the initial tilt angle of the guide plate.

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