Boiler system capable of discharging low-concentration CO and NOX

Abstract

The invention discloses a boiler system capable of discharging low-concentration CO and NOX. The system comprises a hearth, a first-stage economizer, a catalyst reactor, a second-stage economizer, an air preheater, a dust remover and an induced draft fan. The hearth, the first-stage economizer, the second-stage economizer, the air preheater, the dust remover and the induced draft fan are connected in sequence; the number of the catalyst reactors is at least one, and the catalyst reactors are arranged in at least one of the following positions: a position between the primary economizer and the secondary economizer, a position between the secondary economizer and the air preheater, a position between the air preheater and the dust remover, a position between the dust remover and the induced draft fan and an outlet pipeline of the induced draft fan; the catalyst reactor is filled with a multifunctional catalyst, NOX in the boiler flue gas can be reduced into N2, and CO in the boiler flue gas can be oxidized into CO2 at the same time. According to the device and the method, NOX and CO in the boiler flue gas can be efficiently and synergistically removed in a limited space, and the device and the method have relatively high environment-friendly value and economic value.

Description

Technical Field

[0001] This invention belongs to the field of clean combustion and synergistic control of pollutants technology. Specifically, this invention relates to a method for controlling low concentrations of CO and NO. X Boiler systems that discharge pollutants. Background Technology

[0002] During boiler operation, the CO concentration in the flue gas directly affects the boiler's thermal efficiency and is also an important indicator for measuring combustion performance and environmental protection. With increasingly stringent environmental standards, the concentration of NO... X Higher requirements have been placed on NO and CO emission control. However, for new or renovated boiler projects, especially those with limited site space, separately arranging independent SCR denitrification systems and CO oxidation units often faces problems such as insufficient space, system complexity, and high investment and operating costs. Therefore, developing a method that can simultaneously and efficiently remove NO in a single reactor is crucial. X The composite catalyst and system of CO are of great significance for simplifying system configuration, saving layout space, and improving the overall environmental protection and economy of boilers. Summary of the Invention

[0003] This invention addresses the issue of NO in boiler flue gas in existing technologies. X To address the issues of high CO emission concentrations, complex separate treatment systems, and large space requirements, a method for treating low-concentration CO and NO emissions is proposed. X The boiler system emits NO, and this system uses a multifunctional catalyst that integrates traditional SCR denitrification with CO catalytic oxidation to achieve NO reduction. X Synergistic removal of both pollutants, including CO.

[0004] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: This invention provides a method for producing low concentrations of CO and NO. X The boiler system includes a furnace, a primary economizer, a catalyst reactor, a secondary economizer, an air preheater, a dust collector, and an induced draft fan; the furnace, the primary economizer, the secondary economizer, the air preheater, the dust collector, and the induced draft fan are sequentially connected; the catalyst reactor is at least one, and is located at at least one of the following locations: between the primary and secondary economizers, between the secondary economizer and the air preheater, between the air preheater and the dust collector, between the dust collector and the induced draft fan, and on the outlet pipe of the induced draft fan; the catalyst reactor is filled with a multifunctional catalyst, which can simultaneously remove NO from the boiler flue gas. X It is reduced to N2 and the CO in the boiler flue gas is oxidized to CO2.

[0005] Preferably, the catalyst reactor is located between the primary economizer and the secondary economizer.

[0006] In some embodiments, when the temperature of the flue gas in the catalyst reactor is in the range of 280°C to 450°C, the multifunctional catalyst is a high-temperature multifunctional catalyst, which includes a first support, a first active ingredient, a co-catalyst, and a metallic substance in a mass ratio of (85~92):(4~8):(1~3):(1~4). When the temperature of the flue gas in the catalyst reactor is in the range of 100℃~250℃, the multifunctional catalyst is a low-temperature multifunctional catalyst, which includes a second support, a second active ingredient, a noble metal and a metal oxide in a mass ratio of (80~90):(5~12):(2~5):(1~3).

[0007] In some embodiments, the first support in the high-temperature multifunctional catalyst is titanium dioxide; And / or, the first active ingredient is vanadium pentoxide; And / or, the co-catalyst is one or a mixture of two of tungsten trioxide and molybdenum trioxide; And / or, the metallic substance is one or a mixture of two of the following: elemental metals and metal oxides; wherein, the elemental metals include at least one of platinum, palladium, and gold; and the metal oxides include at least one of copper oxide, manganese oxide, cerium dioxide, cobalt tetroxide, and perovskite-type metal oxides.

[0008] In some embodiments, the second carrier is titanium dioxide; And / or, the second active ingredient comprises manganese oxide and cerium oxide in a mass ratio of (6~7):(3~4); And / or, the precious metal includes at least one of platinum, palladium, and gold; And / or, the metal oxide includes at least one of copper oxide, cobalt tetroxide, and perovskite-type metal oxides.

[0009] In some embodiments, the furnace is any one of a pulverized coal boiler furnace, a circulating fluidized bed boiler furnace, or a waste incinerator grate furnace.

[0010] In some embodiments, the air preheater is a tubular air preheater or a rotary air preheater.

[0011] In some embodiments, the dust collector is any one of a bag filter, an electrostatic precipitator, or a hybrid electrostatic-bag filter.

[0012] The advantages and beneficial effects of the embodiments of the present invention are as follows: The boiler system of this invention adopts an integrated NO X A multifunctional catalyst with CO removal capabilities, combined with a flexible system layout, enables the removal of NO from boiler flue gas within a limited space. X Synergistic and efficient purification with CO, significantly reducing NO X This reduces CO emission concentration and improves the economic efficiency and environmental friendliness of boiler flue gas treatment systems. Attached Figure Description

[0013] Figure 1 Low concentrations of CO and NO in embodiments of the present invention X A schematic diagram of a boiler system for emissions.

[0014] Attached reference numerals: 1-furnace, 2-primary economizer, 3-catalyst reactor, 4-secondary economizer, 5-air preheater, 6-dust collector, 7-induced draft fan. Detailed Implementation

[0015] The embodiments of the present invention are described in detail below. These embodiments are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0016] In this invention, when a value is described as a range, it should be understood that such disclosure includes disclosure of all possible subranges within that range, as well as specific numerical values ​​falling within that range, regardless of whether specific numerical values ​​or specific subranges are explicitly specified.

[0017] In this invention, the terms “comprising” and “including” and their various variations mean that other elements or wholes may be included but are not specifically described.

[0018] In this invention, the term "and / or" is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone.

[0019] This invention provides a method for producing low concentrations of CO and NO. XThe boiler system includes a furnace 1, a primary economizer 2, a catalyst reactor 3, a secondary economizer 4, an air preheater 5, a dust collector 6, and an induced draft fan 7. The furnace 1, the primary economizer 2, the secondary economizer 4, the air preheater 5, the dust collector 6, and the induced draft fan 7 are sequentially connected. The catalyst reactor 3 is at least one in number and is located at least in one of the following locations: between the primary economizer 2 and the secondary economizer 4; between the secondary economizer 4 and the air preheater 5; between the air preheater 5 and the dust collector 6; between the dust collector 6 and the induced draft fan 7; and on the outlet pipe of the induced draft fan 7. The catalyst reactor 3 is filled with a multifunctional catalyst that can simultaneously remove NO from the boiler flue gas. X It is reduced to N2 and the CO in the boiler flue gas is oxidized to CO2.

[0020] Preferably, the catalyst reactor 3 is disposed between the primary economizer 2 and the secondary economizer 4.

[0021] In some embodiments, when the temperature of the flue gas in the catalyst reactor 3 is in the range of 280°C to 450°C, the multifunctional catalyst is a high-temperature multifunctional catalyst, which includes a first support, a first active ingredient, a co-catalyst, and a metallic substance in a mass ratio of (85~92):(4~8):(1~3):(1~4). When the temperature of the flue gas in the catalyst reactor 3 is in the range of 100℃~250℃, the multifunctional catalyst is a low-temperature multifunctional catalyst, which includes a second support, a second active ingredient, a noble metal and a metal oxide in a mass ratio of (80~90):(5~12):(2~5):(1~3).

[0022] In some embodiments, the first support in the high-temperature multifunctional catalyst is titanium dioxide (TiO2). And / or, the first active ingredient is vanadium pentoxide (V2O5); And / or, the co-catalyst is one or a mixture of two of tungsten trioxide (WO3) and molybdenum trioxide (MoO3); And / or, the metallic substance is one or a mixture of two of the following: elemental metals and metal oxides; wherein, the elemental metals include at least one of platinum (Pt), palladium (Pd), and gold (Au); and the metal oxides include at least one of copper oxide (CuO), manganese dioxide (MnO2), cerium dioxide (CeO2), cobalt tetroxide (Co3O4), and perovskite-type metal oxides (ABO3 type, such as LaMnO3, LaCoO3, etc.).

[0023] In some embodiments, the second support in the low-temperature multifunctional catalyst is titanium dioxide (TiO2). And / or, the second active ingredient comprises manganese oxide (MnO4) in a mass ratio of (6~7):(3~4). X ) and cerium oxide (CeO2); And / or, the precious metal includes at least one of platinum (Pt), palladium (Pd), and gold (Au); And / or, the metal oxide includes at least one of copper oxide (CuO), cobalt tetroxide (Co3O4), and perovskite-type metal oxides (ABO3 type, such as LaMnO3, LaCoO3, etc.).

[0024] In some embodiments, the furnace 1 is any one of a pulverized coal boiler furnace, a circulating fluidized bed boiler furnace, or a waste incinerator grate furnace.

[0025] In some embodiments, the air preheater 5 is a tubular air preheater or a rotary air preheater.

[0026] In some embodiments, the dust collector 6 is any one of a bag filter, an electrostatic precipitator, or a hybrid electrostatic-bag filter.

[0027] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. Unless otherwise stated, all raw materials used in the embodiments are conventional commercially available products, or can be prepared by known methods; and the experimental methods not specified in the embodiments are conventional methods and conditions well known in the art.

[0028] Example 1 This embodiment provides a low-concentration CO and NO solution. X Boiler systems with emissions (see) Figure 1 The system includes a furnace 1, a primary economizer 2, a catalyst reactor 3, a secondary economizer 4, an air preheater 5, a dust collector 6, and an induced draft fan 7, which are connected in sequence.

[0029] In this embodiment, furnace 1 is a circulating fluidized bed boiler furnace.

[0030] In this embodiment, the air preheater 5 is a tubular air preheater.

[0031] In this embodiment, the dust collector 6 is a bag filter.

[0032] In this embodiment, the catalyst reactor 3 is arranged between the primary economizer 2 and the secondary economizer 4. The flue gas temperature inside the catalyst reactor 3 is about 350°C. The high-temperature multifunctional catalyst filled inside the catalyst reactor 3 is composed of a first support, a first active component, a co-catalyst, and a metal element in a mass ratio of 90:6:2:2. The first support is titanium dioxide (TiO2), the first active component is vanadium pentoxide (V2O5), the co-catalyst includes tungsten trioxide (WO3) and molybdenum trioxide (MoO3) in a mass ratio of 1:1, and the metal element includes platinum (Pt) and palladium (Pd) in a mass ratio of 1:1.

[0033] The working process of the boiler system in this embodiment is as follows: The flue gas flows sequentially through furnace 1 for combustion and primary economizer 2 for initial cooling before entering catalyst reactor 3. Under the action of the high-temperature, multifunctional catalyst in catalyst reactor 3, the NO in the flue gas is reduced... X The gas is reduced to N2, and at the same time, CO in the flue gas is oxidized to CO2, thus achieving efficient synergistic removal of the two pollutants. The treated flue gas then passes through a secondary economizer 4, an air preheater 5, a dust collector 6, and an induced draft fan 7 before being discharged.

[0034] The boiler system of this embodiment can achieve a CO removal rate of ≥90% and NO removal rate of ≥90% in flue gas. X The removal rate is ≥95% (in standard NH3 / NO). X (Under the condition of molar ratio ≈ 1.0).

[0035] Example 2 The boiler system in this embodiment is basically the same as that in Embodiment 1, except that: in this embodiment, the catalyst reactor is arranged between the secondary economizer and the air preheater; and the flue gas temperature in the catalyst reactor is approximately 200°C. The low-temperature multifunctional catalyst filled in the reactor consists of a second support (TiO2) and a second active component (MnO2) in a mass ratio of 85:8:4:3. X It consists of a mixture of CeO2 (at a mass ratio of 6.5:3.5), precious metals (Pd), and metal oxides (LaMnO3). This system is suitable for retrofitting the tail-end low-temperature zone of existing boilers, achieving NO reduction within limited retrofit space. X Co-removal of CO.

[0036] The boiler system of this embodiment can achieve a CO removal rate of ≥85% and NO removal rate of ≥85% in flue gas. X The removal rate reaches 80%~85%.

[0037] Example 3 The boiler system in this embodiment is basically the same as that in embodiment 1, except that the furnace in this embodiment is a pulverized coal boiler furnace, the air preheater is a rotary air preheater, and the dust collector is an electrostatic precipitator-bag filter.

[0038] The boiler system of this embodiment can achieve a CO removal rate of 88%~92% and NO removal rate of [missing information - likely related to CO removal]. X The removal rate reaches 92%~95%.

[0039] Example 4 The boiler system in this embodiment is basically the same as that in Embodiment 1, except that: the boiler system in this embodiment includes two catalyst reactors: the first catalyst reactor is the same as in Embodiment 1, arranged between the primary and secondary economizers (high-temperature section, ~380℃), and filled with the high-temperature multifunctional catalyst as described in Embodiment 1; the second catalyst reactor is arranged between the dust collector and the induced draft fan (low-temperature section, approximately 150℃), and filled with the low-temperature multifunctional catalyst as described in Embodiment 2. Through two-stage catalysis, more complex flue gas conditions and stricter emission standards can be addressed.

[0040] The boiler system of this embodiment can achieve a CO removal rate of ≥95% and NO removal rate of ≥95% in flue gas. X The removal rate is ≥98%.

[0041] Example 5 The boiler system in this embodiment is basically the same as that in Embodiment 1, except that the high-temperature multifunctional catalyst filled in the catalyst reactor of the boiler system in this embodiment is composed of a first support, a first active component, a co-catalyst, and metal oxides in a mass ratio of 90:6:2:2. The first support is titanium dioxide (TiO2), the first active component is vanadium pentoxide (V2O5), the co-catalyst includes tungsten trioxide (WO3) and molybdenum trioxide (MoO3) in a mass ratio of 1:1, and the metal oxides include copper oxide (CuO) and cerium dioxide (CeO2) in a mass ratio of 1:1.

[0042] The boiler system of this embodiment can achieve a CO removal rate of 75%~85% and NO removal rate of [missing information - likely related to CO removal]. X The removal rate reached ≥94%.

[0043] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0044] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0045] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0046] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0047] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0048] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A low-concentration CO and NO X The boiler system for emissions is characterized by, The system includes a furnace, a primary economizer, a catalyst reactor, a secondary economizer, an air preheater, a dust collector, and an induced draft fan; the furnace, the primary economizer, the secondary economizer, the air preheater, the dust collector, and the induced draft fan are sequentially connected; the catalyst reactor is at least one, and it is located at at least one of the following locations: between the primary and secondary economizers, between the secondary economizer and the air preheater, between the air preheater and the dust collector, between the dust collector and the induced draft fan, and on the outlet pipe of the induced draft fan; the catalyst reactor is filled with a multifunctional catalyst, which can simultaneously remove NO from the boiler flue gas. X It is reduced to N2 and the CO in the boiler flue gas is oxidized to CO2.

2. The low concentration CO and NO according to claim 1 X The boiler system for emissions is characterized by, The catalyst reactor is positioned between the primary economizer and the secondary economizer.

3. The low concentration CO and NO as described in claim 1 X The boiler system for emissions is characterized by, When the temperature of the flue gas in the catalyst reactor is in the range of 280℃~450℃, the multifunctional catalyst is a high-temperature multifunctional catalyst, which includes a first support, a first active ingredient, a co-catalyst and a metallic substance in a mass ratio of (85~92):(4~8):(1~3):(1~4). When the temperature of the flue gas in the catalyst reactor is in the range of 100℃~250℃, the multifunctional catalyst is a low-temperature multifunctional catalyst, which includes a second support, a second active ingredient, a noble metal and a metal oxide in a mass ratio of (80~90):(5~12):(2~5):(1~3).

4. The low concentration CO and NO according to claim 3 X The boiler system for emissions is characterized by, In the high-temperature multifunctional catalyst, the first support is titanium dioxide; And / or, the first active ingredient is vanadium pentoxide; And / or, the co-catalyst is one or a mixture of two of tungsten trioxide and molybdenum trioxide; And / or, the metallic substance is one or a mixture of two of the following: elemental metals and metal oxides; wherein, the elemental metals include at least one of platinum, palladium, and gold; and the metal oxides include at least one of copper oxide, manganese oxide, cerium dioxide, cobalt tetroxide, and perovskite-type metal oxides.

5. The low concentration CO and NO as described in claim 3 X The boiler system for emissions is characterized by, In the low-temperature multifunctional catalyst, the second support is titanium dioxide; And / or, the second active ingredient comprises manganese oxide and cerium oxide in a mass ratio of (6~7):(3~4); And / or, the precious metal includes at least one of platinum, palladium, and gold; And / or, the metal oxide includes at least one of copper oxide, cobalt tetroxide, and perovskite-type metal oxides.

6. The low concentration CO and NO according to claim 1 X The boiler system for emissions is characterized by, The furnace can be any one of the following: pulverized coal boiler furnace, circulating fluidized bed boiler furnace, or waste incinerator grate furnace.

7. The low concentration CO and NO according to claim 1 X The boiler system for emissions is characterized by, The air preheater is either a tubular air preheater or a rotary air preheater.

8. The low concentration CO and NO according to claim 1 X The boiler system for emissions is characterized by, The dust collector is any one of a bag filter, an electrostatic precipitator, or a hybrid electrostatic-bag filter.

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