A method for simultaneously removing CO and NO from sintering flue gas x System and method

Abstract

The present invention relates to the technical field of treating sintering flue gas, and in particular to a method for simultaneously removing CO and NO from sintering flue gas. x The system and method include a multifunctional oxidation layer and an SCR catalyst layer sequentially arranged on the flue; a heat exchange device is connected between the flue upstream of the multifunctional oxidation layer and the flue downstream of the SCR catalyst layer, so that the flue upstream of the multifunctional oxidation layer and the flue downstream of the SCR catalyst layer can exchange heat. Based on this system, the present invention also provides a method for simultaneously removing CO and NO from sintering flue gas. x The present invention can make full use of the heat released during the oxidation of carbon monoxide to reduce energy consumption; it can also utilize the turbulence and other effects of catalysts in different forms to achieve flue gas mixing, dispersion, flow rate adjustment, etc., without the need to install a gas rectifier, simplifying the reaction device; it can not only use ammonia for SCR catalytic denitrification, but also use CO contained in the flue gas for SCR catalytic denitrification.

Description

Technical Field

[0001] The present invention relates to the technical field of treating sintering flue gas, and in particular to a method for simultaneously removing CO and NO from sintering flue gas. x systems and methods. Background Art

[0002] The steel industry’s atmospheric pollutants mainly come from the sintering / pelletizing process. Each ton of sintered ore produces approximately 4,000-8,000 m 3 Sintering flue gas contains 100-400mg / Nm 3 NO, 400~2000mg / Nm 3 vol% SO2, 8-13vol% water vapor, 14-18vol% O2 and 0.6%-1.2vol% CO. With the gradual implementation of ultra-low emission policies in the steel industry, dust, SO2, NO x The emissions of steel and iron ore have been greatly reduced, but the problem of increasing CO emissions has gradually emerged. In some areas where steel enterprises are concentrated, the CO concentration exceeds the first-level air quality standard by 30-50%, becoming the main air pollutant in some local areas.

[0003] Medium and low temperature NH3-SCR technology occupies a high market share in sintering flue gas treatment with high denitrification rate and low investment cost. Medium and low temperature NH3-SCR uses NH3 as a reducing agent, and the ratio of NH3 / NOx introduced is about 1:1. The working temperature is generally 180-250℃, which is higher than the emission temperature of sintering flue gas. Therefore, after desulfurization, the flue gas needs to be heated by heat exchange, and then heated to the target temperature by an external heat source (generally additional heating of 30-50℃ is required), and then mixed with the diluted ammonia delivered by the ammonia station through the ammonia spraying grid, and enters the denitrification bed for NH3-SCR reaction. The treated clean gas is discharged after heat recovery.

[0004] The above conventional scheme requires an external heat source, which increases energy consumption. However, the use of carbon monoxide catalytic oxidation technology to oxidize CO in the sintering flue gas can generate heat that can raise the sintering flue gas temperature by 30-60°C, thereby saving additional heating heat sources, not only reducing energy consumption, but also reducing CO emissions in the sintering flue gas.

[0005] Chinese patent CN212236736U provides a combined removal device for carbon monoxide and nitrogen oxides from sintering flue gas, which is equipped with a flue, a heating system, a carbon monoxide catalytic reaction system, an ammonia injection system, a static rectifier and a low-temperature SCR denitration reaction system. A rectifier is provided at the front end of the SCR denitration device, and the ammonia flow rate content in the flue gas entering the SCR denitration reaction system is adjusted by the rectifier. The overall device structure is complex. Chinese patent CN211753933U provides a carbon monoxide and nitrogen oxide coordinated treatment system, which is equipped with a first CO catalytic oxidation device, an ammonia injection device, a rectifier, an SCR denitration device, and a second CO catalytic oxidation device. The system also needs to be equipped with a rectifier before the SCR denitration to adjust the ammonia flow rate content in the flue gas entering the SCR denitration reaction system. Summary of the invention

[0006] The purpose of the present invention is to provide a method for simultaneously removing CO and NO from sintering flue gas. x The system can make full use of the heat released by carbon monoxide oxidation, reduce the energy consumption of the system, and simplify the reaction device by utilizing the turbulence effect of catalysts with different morphologies.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows:

[0008] A system for simultaneously removing CO and NOx from sintering flue gas comprises a multifunctional oxidation layer and an SCR catalyst layer which are sequentially arranged on a flue; a heat exchange device is connected between the flue upstream of the multifunctional oxidation layer and the flue downstream of the SCR catalyst layer for heat exchange between the flue upstream of the multifunctional oxidation layer and the flue downstream of the SCR catalyst layer.

[0009] Preferably, a primary oxidation layer is also provided on the flue between the multifunctional oxidation layer and the heat exchange device.

[0010] The primary oxidation layer is a honeycomb / plate-type oxidation layer, which contains a honeycomb-type carbon monoxide oxidation catalyst or a plate-type carbon monoxide oxidation catalyst; the primary oxidation layer can oxidize a large amount of CO to release heat and increase the flue gas temperature. The shape of the honeycomb or plate-type primary oxidation layer can reduce the pressure drop of the flue gas and can carry flue gas with a large ash content;

[0011] The multifunctional oxidation layer is a granular oxidation layer, which is equipped with a spherical carbon monoxide oxidation catalyst, a columnar carbon monoxide oxidation catalyst or a multifunctional catalyst. The multifunctional catalyst can oxidize CO and promote the oxidation of NO to NO2. The granular multifunctional oxidation layer is close to the SCR catalyst layer. By adjusting the angle and thickness of the multifunctional oxidation layer and cooperating with the granular catalyst, the various components of the flue gas can be mixed more evenly and the gas velocity can be more balanced, replacing the gas rectifier. When the multifunctional oxidation layer is equipped with a multifunctional catalyst, it can also promote the oxidation of NO in the flue gas to NO2, because the reaction kinetic rate of the ordinary SCR denitrification reaction is low at medium and low temperatures, and the fast SCR reaction requires more NO2. Through the promotion of the multifunctional catalyst, the NO2 content in the flue gas increases, which is beneficial to the denitrification of the subsequent SCR catalyst layer.

[0012] Preferably, the multifunctional catalyst is a metal oxide active component supported on a metal oxide carrier.

[0013] More preferably, the multifunctional catalyst is titanium dioxide supported on one or more of copper, cerium, manganese and cobalt oxides.

[0014] The SCR catalyst layer contains an ammonia SCR catalyst or a carbon monoxide SCR catalyst. The ammonia SCR catalyst can be used in combination with ammonia as a reducing agent to perform SCR denitration, and the carbon monoxide SCR catalyst can be used in combination with carbon monoxide as a reducing agent to perform SCR denitration.

[0015] Preferably, the system further comprises an ammonia injection device arranged on the flue between the primary oxidation layer and the multifunctional oxidation layer.

[0016] Preferably, the system further comprises a tail end catalyst layer disposed on the flue between the SCR catalyst layer and the heat exchange device; a carbon monoxide oxidation catalyst is installed in the tail end catalyst layer.

[0017] Furthermore, the multifunctional oxidation layer has an inclination angle with one side being thinner and the other side being thicker, which changes with the curvature of the flue or changes with its own setting, and both the inclination angle and the average thickness of the multifunctional oxidation layer can be adjusted.

[0018] The inclination angle is 0-15°, and the average thickness of the multifunctional oxide layer is 20-35 cm.

[0019] Furthermore, the multifunctional oxide layer is placed in an elastic metal wire mesh, a bracket is provided at the bottom of the multifunctional oxide layer, the other end of the bracket is connected to the inner wall of the flue, the bracket can rotate around a fulcrum on the inner wall of the flue, and the rotation of the bracket can adjust the inclination angle of the multifunctional oxide layer.

[0020] Furthermore, bolts are arranged above and below the elastic metal wire mesh, and the thickness of the elastic metal wire mesh can be adjusted by the bolts, so that the inner catalyst of the multifunctional oxidation layer installed in the elastic metal wire mesh becomes tight or loose.

[0021] After the flue gas enters the flue, its flow rate and other factors will change at the flue corner. It is preferred to set the multifunctional oxidation layer at the flue corner. Through this setting, the inclination angle and thickness of different multifunctional oxidation layers are adjusted according to the initial flow rate of the flue gas entering the flue, the amount of flue gas ash, etc., and the different forms of the oxidation catalyst itself are used to achieve mixing, dispersion, and flow rate adjustment of the flue gas. There is no need to install an additional gas rectifier, so that the flue gas can better undergo a denitrification reaction after entering the SCR catalyst layer.

[0022] As another solution, multiple layers of porous plates with different inclination angles are arranged in the middle part of the multifunctional oxidation layer, and the pore size of the porous plates is smaller than the catalyst particle size of the multifunctional oxidation layer. By arranging porous plates with different numbers of layers and different angles and utilizing the guiding effect of the porous plates, the catalyst forms different angles after being filled into the multifunctional oxidation layer, thereby adjusting the inclination angle and thickness of the multifunctional oxidation layer.

[0023] The present invention also provides a method for simultaneously removing CO and NOx from sintering flue gas using the above system, comprising the following steps:

[0024] S1: The flue gas is heated by the heat exchange device;

[0025] S4: The heated flue gas enters the multifunctional oxidation layer, where CO oxidation releases heat to increase the flue gas temperature and promotes oxidation of NO in the flue gas to NO2. At the same time, the thickness and inclination angle of the multifunctional oxidation layer are adjusted to make the gas concentration and flow rate more balanced.

[0026] S5: After passing through the multifunctional oxidation layer, the flue gas enters the SCR catalyst layer for denitration reaction;

[0027] S7: The flue gas after denitrification is recovered through the heat exchange device for waste heat recovery and then discharged cleanly.

[0028] Preferably, step S2 and / or step S3 are further included between step S1 and step S3, and step S2 is: the flue gas heated by the heat exchange device enters the primary oxidation layer to perform CO oxidation while increasing the flue gas temperature;

[0029] The step S3 is: mixing the heated flue gas with the ammonia injected through the ammonia injection device.

[0030] Preferably, step S6 is further included between steps S5 and S7, and step S6 is: the flue gas after denitration enters the tail end catalyst layer to perform thorough CO oxidation.

[0031] Compared with the prior art, the present invention has the following advantages:

[0032] (1) The heat released during the oxidation of carbon monoxide can be fully utilized, eliminating the need to supplement heat outside the system and reducing energy consumption.

[0033] (2) By utilizing the turbulence effect of oxidation catalysts in different forms, the flue gas can be mixed, dispersed, and the flow rate can be adjusted, thereby eliminating the need to install rectifiers and other devices, simplifying the system's reaction device.

[0034] (3) The inclination angle and thickness of the multifunctional oxidation layer can be adjusted according to different initial flue gas conditions to make the flue gas concentration and flow rate more balanced. At the same time, the multifunctional oxidation layer promotes the oxidation of NO to NO2, so that NO and NO2 are dynamically balanced under flue gas conditions, which is conducive to faster subsequent SCR denitrification.

[0035] (4) The system can not only cooperate with ammonia for SCR catalytic denitrification, but also directly use carbon monoxide in the flue gas as a reducing agent for SCR catalytic denitrification. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a structural diagram of this system;

[0037] Figure 2 is a schematic diagram of the multifunctional oxide layer structure;

[0038] Figure 3 This is the NH3-SCR denitration process of Example 3;

[0039] Figure 4 This is the CO-SCR denitrification process of Example 10.

[0040] In the figure: 1-heat exchange device, 2-primary oxidation layer, 3-ammonia injection device, 4-multifunctional oxidation layer, 5-SCR catalyst layer, 6-tail catalyst layer, 7-flue, 8-bracket, 9-bolt. DETAILED DESCRIPTION

[0041] As used herein:

[0042] "Prepared from" is synonymous with "comprising." As used herein, the terms "comprising," "including," "having," "containing," or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises the listed elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

[0043] When an amount, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper preferred values ​​and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pairing of any range upper limit or preferred value with any range lower limit or preferred value, regardless of whether the range is disclosed separately. For example, when a range of "1 to 5" is disclosed, the described range should be interpreted as including ranges "1 to 4", "1 to 3", "1 to 2", "1 to 2 and 4 to 5", "1 to 3 and 5", etc. When a numerical range is described in this article, unless otherwise stated, the range is intended to include its end values ​​and all integers and fractions within the range.

[0044] "And / or" is used to indicate that one or both of the stated situations may occur, for example, A and / or B includes (A and B) and (A or B).

[0045] The technical solutions of the present invention will be described in detail below in conjunction with specific embodiments. However, those skilled in the art will appreciate that the following embodiments are only used to illustrate the present invention and should not be construed as limiting the scope of the present invention.

[0046] Example 1

[0047] A method for simultaneously removing CO and NO from sintering flue gas x The system comprises a heat exchange device 1, a primary oxidation layer 2, an ammonia injection device 3, a multifunctional oxidation layer 4, and an SCR catalyst layer 5 which are sequentially arranged on a flue 7.

[0048] The primary oxide layer 2 contains 1m 3 The multifunctional oxidation layer 4 is provided with a spherical carbon monoxide oxidation catalyst with a diameter of 5 mm. The multifunctional oxidation layer 4 is 20 cm thick and has an inclination angle of 10°. The multifunctional oxidation layer 4 is placed in an elastic metal mesh. A bracket 8 is provided at the bottom of the multifunctional oxidation layer 4. The other end of the bracket is connected to the inner wall of the flue 7 and can rotate around the fulcrum on the inner wall of the flue 7. Bolts 9 are provided above and below the elastic metal mesh. Figure 2 As shown; the SCR catalyst layer 5 is equipped with an ammonia SCR catalyst.

[0049] The test sintering flue gas components used are: water content 10%, carbon monoxide content 6500ppm, nitrogen oxide content 200ppm, flue gas flow rate 3000m 3 / h, the starting temperature is 130°C, and it is increased to 200°C through the heat exchange device 1.

[0050] The heated flue gas enters the primary oxidation layer 2, the carbon monoxide removal rate at the outlet of the primary oxidation layer 2 is 80%, and the flue gas temperature rises by 39°C; after mixing with the ammonia injected by the ammonia injection device 3, it enters the multifunctional oxidation layer 4, and the carbon monoxide removal rate at the outlet of the multifunctional oxidation layer 4 is 100%; before the flue gas enters the SCR catalyst layer 5, the ammonia concentration Cv value is 4.2%, the flow rate Cv value is 12.9%, the temperature is 248°C, the nitrogen oxide removal rate at the outlet of the SCR catalyst layer 5 is 88%, and the flue gas enters the heat exchange device 1 to recover the waste heat and then is discharged cleanly.

[0051] Example 2

[0052] A method for simultaneously removing CO and NO from sintering flue gas x The device comprises a heat exchange device 1, a primary oxidation layer 2, an ammonia injection device 3, a multifunctional oxidation layer 4, and an SCR catalyst layer 5 which are sequentially arranged on a flue 7.

[0053] The primary oxide layer 2 contains 1m 3 The multifunctional oxidation layer 4 is equipped with a spherical carbon monoxide oxidation catalyst with a diameter of 5 mm, the multifunctional oxidation layer 4 is 20 cm thick, the inclination angle is 10°, and 5 layers of porous plates are arranged inside the multifunctional oxidation layer 4, and the pore size of the porous plates is 4 mm; the SCR catalyst layer 5 is equipped with an ammonia SCR catalyst.

[0054] The test sintering flue gas components used are: water content 10%, carbon monoxide content 6500ppm, nitrogen oxide content 200ppm, flue gas flow rate 3000m 3 / h, the starting temperature is 130°C, and it is increased to 200°C through the heat exchange device 1.

[0055] The heated flue gas enters the primary oxidation layer 2, the carbon monoxide removal rate at the outlet of the primary oxidation layer 2 is 74%, and the flue gas temperature rises by 36°C; after mixing with the ammonia injected by the ammonia injection device 3, it enters the multifunctional oxidation layer 4, and the carbon monoxide removal rate at the outlet of the multifunctional oxidation layer 4 is 100%; before the flue gas enters the SCR catalyst layer 5, the ammonia concentration Cv value is 5.2%, the flow rate Cv value is 13.8%, the temperature is 247°C, the nitrogen oxide removal rate at the outlet of the SCR catalyst layer 5 is 86%, and the flue gas enters the heat exchanger 1 to recover the waste heat and then is discharged cleanly.

[0056] Example 3

[0057] A method for simultaneously removing CO and NO from sintering flue gas x systems such as Figure 1 As shown, it includes a heat exchange device 1, a primary oxidation layer 2, an ammonia injection device 3, a multifunctional oxidation layer 4, an SCR catalyst layer 5, and a tail catalyst layer 6 which are sequentially arranged on a flue 7.

[0058] The primary oxide layer 2 contains 1m 3 25-hole honeycomb carbon monoxide oxidation catalyst; a multifunctional catalyst with a diameter of 5 mm is installed in the multifunctional oxidation layer 4, the multifunctional oxidation layer 4 is 20 cm thick, the inclination angle is 10°, the multifunctional oxidation layer 4 is placed in the elastic metal wire mesh, and a bracket 8 is provided at the bottom of the multifunctional oxidation layer 4. The other end of the bracket is connected to the inner wall of the flue 7 and can rotate around the fulcrum on the inner wall of the flue 7. Bolts 9 are provided above and below the elastic metal wire mesh, such as Figure 2 As shown; the SCR catalyst layer 5 is equipped with an ammonia SCR catalyst, and the tail catalyst layer 6 is equipped with a 10cm diameter 3cm spherical carbon monoxide oxidation catalyst.

[0059] The multifunctional catalyst is copper oxide and cerium oxide loaded on a titanium dioxide carrier.

[0060] The test sintering flue gas components used are: water content 10%, carbon monoxide content 6500ppm, nitrogen oxide content 200ppm, flue gas flow rate 3000m 3 / h, starting temperature 130℃, and rising to 200℃ through heat exchanger 1.

[0061] like Figure 3 As shown, the heated flue gas enters the primary oxidation layer 2, the carbon monoxide removal rate at the outlet of the primary oxidation layer 2 is 80%, and the flue gas temperature rises by 39°C; after mixing with the ammonia injected by the ammonia injection device 3, it enters the multifunctional oxidation layer 4, and the carbon monoxide removal rate at the outlet of the multifunctional oxidation layer 4 is 98%; before the flue gas enters the SCR catalyst layer 5, the ammonia concentration Cv value is 4.5%, the flow rate Cv value is 14.5%, the temperature is 245°C, the nitrogen oxide removal rate at the outlet of the SCR catalyst layer 5 is 93%, and the carbon monoxide removal rate is 100% after the flue gas passes through the tail catalyst layer 6, and enters the heat exchanger 1 to recover the waste heat and then be discharged cleanly.

[0062] Example 4

[0063] A method for simultaneously removing CO and NO from sintering flue gas x The device comprises a heat exchange device 1, a primary oxidation layer 2, an ammonia injection device 3, a multifunctional oxidation layer 4, an SCR catalyst layer 5, and a tail catalyst layer 6 which are sequentially arranged on a flue 7.

[0064] The primary oxide layer 2 contains 1m 3 The multifunctional oxidation layer 4 is provided with a multifunctional catalyst with a diameter of 5 mm, the thickness of the multifunctional oxidation layer 4 is 20 cm, the inclination angle is 10°, and 5 layers of porous plates are arranged inside the multifunctional oxidation layer 4, the inclination angle is 10°, and the pore size of the porous plates is 4 mm; the SCR catalyst layer 5 is provided with an ammonia SCR catalyst, and the tail catalyst layer 6 is provided with a 10 cm diameter 3 cm spherical carbon monoxide oxidation catalyst.

[0065] The multifunctional catalyst is a titanium dioxide carrier loaded with copper oxide, manganese oxide and cobalt oxide.

[0066] The test sintering flue gas components used are: water content 10%, carbon monoxide content 6500ppm, nitrogen oxide content 200ppm, flue gas flow rate 5000m 3 / h, starting temperature 130℃, and rising to 200℃ through heat exchanger 1.

[0067] The heated flue gas enters the primary oxidation layer 2, the carbon monoxide removal rate at the outlet of the primary oxidation layer 2 is 74%, and the flue gas temperature rises by 36°C; after mixing with the ammonia injected by the ammonia injection device 3, it enters the multifunctional oxidation layer 4, and the carbon monoxide removal rate at the outlet of the multifunctional oxidation layer 4 is 92%; before the flue gas enters the SCR catalyst layer 5, the ammonia concentration Cv value is 4.6%, the flow rate Cv value is 15.6%, the temperature is 241°C, the nitrogen oxide removal rate at the outlet of the SCR catalyst layer 5 is 92%, and the carbon monoxide removal rate is 100% after the flue gas passes through the tail catalyst layer 6, and enters the heat exchanger 1 to recover the waste heat and then be discharged cleanly.

[0068] Example 5

[0069] A method for simultaneously removing CO and NO from sintering flue gas x The system comprises a heat exchange device 1, a primary oxidation layer 2, an ammonia injection device 3, a multifunctional oxidation layer 4, and an SCR catalyst layer 5 which are sequentially arranged on a flue 7.

[0070] The primary oxide layer 2 contains 1m 3 A 25-hole honeycomb carbon monoxide oxidation catalyst; a spherical carbon monoxide oxidation catalyst with a diameter of 5 mm is installed in the multifunctional oxidation layer 4, the multifunctional oxidation layer 4 is 35 cm thick, the inclination angle is 0°, the multifunctional oxidation layer 4 is placed in an elastic metal wire mesh, a bracket 8 is provided at the bottom of the multifunctional oxidation layer 4, the other end of the bracket is connected to the inner wall of the flue 7, and can rotate around the fulcrum on the inner wall of the flue 7; bolts 9 are provided above and below the elastic metal wire mesh; the SCR catalyst layer 5 is equipped with an ammonia SCR catalyst.

[0071] The test sintering flue gas components used are: water content 10%, carbon monoxide content 6500ppm, nitrogen oxide content 200ppm, flue gas flow rate 5000m 3 / h, the starting temperature is 130°C, and it is increased to 200°C through the heat exchange device 1.

[0072] The heated flue gas enters the primary oxidation layer 2, the carbon monoxide removal rate at the outlet of the primary oxidation layer 2 is 80%, and the flue gas temperature rises by 39°C; after mixing with the ammonia injected by the ammonia injection device 3, it enters the multifunctional oxidation layer 4, and the carbon monoxide removal rate at the outlet of the multifunctional oxidation layer 4 is 100%; before the flue gas enters the SCR catalyst layer 5, the ammonia concentration Cv value is 4.0%, the flow rate Cv value is 13.8%, the temperature is 248°C, the nitrogen oxide removal rate at the outlet of the SCR catalyst layer 5 is 88%, and the flue gas enters the heat exchange device 1 to recover the waste heat and then is discharged cleanly.

[0073] Example 6

[0074] A method for simultaneously removing CO and NO from sintering flue gas x The system comprises a heat exchange device 1, a primary oxidation layer 2, an ammonia injection device 3, a multifunctional oxidation layer 4, and an SCR catalyst layer 5 which are sequentially arranged on a flue 7.

[0075] The primary oxide layer 2 contains 1m 3 A 25-hole honeycomb carbon monoxide oxidation catalyst; a spherical carbon monoxide oxidation catalyst with a diameter of 5 mm is installed in the multifunctional oxidation layer 4, the thickness of the multifunctional oxidation layer 4 is 30 cm, the inclination angle is 15°, the multifunctional oxidation layer 4 is placed in an elastic metal wire mesh, a bracket 8 is provided at the bottom of the multifunctional oxidation layer 4, the other end of the bracket is connected to the inner wall of the flue 7, and can rotate around the fulcrum on the inner wall of the flue 7; bolts 9 are provided above and below the elastic metal wire mesh; the SCR catalyst layer 5 is equipped with an ammonia SCR catalyst.

[0076] The test sintering flue gas components used are: water content 10%, carbon monoxide content 6500ppm, nitrogen oxide content 200ppm, flue gas flow rate 5000m 3 / h, the starting temperature is 130°C, and it is increased to 200°C through the heat exchange device 1.

[0077] The heated flue gas enters the primary oxidation layer 2, the carbon monoxide removal rate at the outlet of the primary oxidation layer 2 is 80%, and the flue gas temperature rises by 39°C; after mixing with the ammonia injected by the ammonia injection device 3, it enters the multifunctional oxidation layer 4, and the carbon monoxide removal rate at the outlet of the multifunctional oxidation layer 4 is 100%; before the flue gas enters the SCR catalyst layer 5, the ammonia concentration Cv value is 3.9%, the flow rate Cv value is 12.2%, the temperature is 248°C, the nitrogen oxide removal rate at the outlet of the SCR catalyst layer 5 is 88%, and the flue gas enters the heat exchange device 1 to recover the waste heat and then is discharged cleanly.

[0078] Example 7

[0079] A method for simultaneously removing CO and NO from sintering flue gas xThe system comprises a heat exchange device 1, a primary oxidation layer 2, an ammonia injection device 3, a multifunctional oxidation layer 4, an SCR catalyst layer 5, and a tail catalyst layer 6 which are sequentially arranged on a flue 7.

[0080] The primary oxide layer 2 contains 1m 3 A 25-hole honeycomb carbon monoxide oxidation catalyst; a multifunctional oxidation layer 4 is filled with a spherical carbon monoxide oxidation catalyst with a diameter of 5 mm, the multifunctional oxidation layer 4 is 20 cm thick, the inclination angle is 10°, the multifunctional oxidation layer 4 is placed in an elastic metal wire mesh, a bracket 8 is provided at the bottom of the multifunctional oxidation layer 4, the other end of the bracket is connected to the inner wall of the flue 7, and can rotate around the fulcrum on the inner wall of the flue 7, and bolts 9 are provided above and below the elastic metal wire mesh; the SCR catalyst layer 5 is filled with an ammonia SCR catalyst, and the tail catalyst layer 6 is filled with a 10 cm diameter 3 cm spherical carbon monoxide oxidation catalyst.

[0081] The test sintering flue gas components used are: water content 10%, carbon monoxide content 6500ppm, nitrogen oxide content 200ppm, flue gas flow rate 5000m 3 / h, the starting temperature is 120℃, which is increased to 160℃ through heat exchanger 1.

[0082] The heated flue gas enters the primary oxidation layer 2, the carbon monoxide removal rate at the outlet of the primary oxidation layer 2 is 50%, and the flue gas temperature rises by 25°C; after mixing with the ammonia injected by the ammonia injection device 3, it enters the multifunctional oxidation layer 4, and the carbon monoxide removal rate at the outlet of the multifunctional oxidation layer 4 is 91%; before the flue gas enters the SCR catalyst layer 5, the ammonia concentration Cv value is 4.2%, the flow rate Cv value is 12.3%, the temperature is 241°C, the nitrogen oxide removal rate at the outlet of the SCR catalyst layer 5 is 81%, and the carbon monoxide removal rate is 100% after the flue gas passes through the tail catalyst layer 6, and enters the heat exchanger 1 to recover the waste heat and then be discharged cleanly.

[0083] Example 8

[0084] A method for simultaneously removing CO and NO from sintering flue gas x The system comprises a heat exchange device 1, a primary oxidation layer 2, an ammonia injection device 3, a multifunctional oxidation layer 4, an SCR catalyst layer 5, and a tail catalyst layer 6 which are sequentially arranged on a flue 7.

[0085] The primary oxide layer 2 contains 1m 3A 25-hole honeycomb carbon monoxide oxidation catalyst; a multifunctional oxidation layer 4 is filled with a spherical carbon monoxide oxidation catalyst with a diameter of 5 mm, the multifunctional oxidation layer 4 is 20 cm thick, the inclination angle is 10°, the multifunctional oxidation layer 4 is placed in an elastic metal wire mesh, a bracket 8 is provided at the bottom of the multifunctional oxidation layer 4, the other end of the bracket is connected to the inner wall of the flue 7, and can rotate around the fulcrum on the inner wall of the flue 7, and bolts 9 are provided above and below the elastic metal wire mesh; the SCR catalyst layer 5 is filled with an ammonia SCR catalyst, and the tail catalyst layer 6 is filled with a 10 cm diameter 3 cm spherical carbon monoxide oxidation catalyst.

[0086] The test sintering flue gas components used are: water content 4%, carbon monoxide content 6500ppm, nitrogen oxide content 200ppm, flue gas flow rate 5000m 3 / h, the starting temperature is 130℃, which is increased to 180℃ through heat exchanger 1.

[0087] The heated flue gas enters the primary oxidation layer 2, the carbon monoxide removal rate at the outlet of the primary oxidation layer 2 is 68%, and the flue gas temperature rises by 30°C; after mixing with the ammonia injected by the ammonia injection device 3, it enters the multifunctional oxidation layer 4, and the carbon monoxide removal rate at the outlet of the multifunctional oxidation layer 4 is 95%; before the flue gas enters the SCR catalyst layer 5, the ammonia concentration Cv value is 4.4%, the flow rate Cv value is 12.8%, the temperature is 245°C, the nitrogen oxide removal rate at the outlet of the SCR catalyst layer 5 is 81%, and the carbon monoxide removal rate is 100% after the flue gas passes through the tail catalyst layer 6, and enters the heat exchanger 1 to recover the waste heat and then be discharged cleanly.

[0088] Example 9

[0089] A method for simultaneously removing CO and NO from sintering flue gas x The system comprises a heat exchange device 1, a primary oxidation layer 2, a multifunctional oxidation layer 4, an SCR catalyst layer 5, and a tail catalyst layer 6 which are sequentially arranged on a flue 7.

[0090] The primary oxide layer 2 contains 0.2m 3 A 25-hole honeycomb carbon monoxide oxidation catalyst; a multifunctional oxidation layer 4 is filled with a columnar carbon monoxide oxidation catalyst with a diameter of 5 mm, the multifunctional oxidation layer 4 is 20 cm thick, the inclination angle is 10°, the multifunctional oxidation layer 4 is placed in an elastic metal wire mesh, a bracket 8 is provided at the bottom of the multifunctional oxidation layer 4, the other end of the bracket is connected to the inner wall of the flue 7, and can rotate around the fulcrum on the inner wall of the flue 7, and bolts 9 are provided above and below the elastic metal wire mesh; the SCR catalyst layer 5 is filled with a carbon monoxide SCR catalyst, and the tail catalyst layer 6 is filled with a 20 cm diameter 5 cm spherical carbon monoxide oxidation catalyst.

[0091] The test sintering flue gas components used are: water content 10%, carbon monoxide content 6500ppm, nitrogen oxide content 200ppm, flue gas flow rate 3000m 3 / h, starting temperature 130℃, and rising to 200℃ through heat exchanger 1.

[0092] The heated flue gas enters the primary oxidation layer 2, the carbon monoxide removal rate at the outlet of the primary oxidation layer 2 is 31%, and the flue gas temperature rises by 21°C; then it enters the multifunctional oxidation layer 4, the carbon monoxide removal rate at the outlet of the multifunctional oxidation layer 4 is 60%; before the flue gas enters the SCR catalyst layer 5, the flow rate Cv value is 12.8%, the temperature is 208°C, the nitrogen oxide removal rate at the outlet of the SCR catalyst layer 5 is 80%, and the carbon monoxide removal rate is 100% after the flue gas passes through the tail catalyst layer 6, and enters the heat exchanger 1 to recover the waste heat and then be discharged cleanly.

[0093] Example 10

[0094] A method for simultaneously removing CO and NO from sintering flue gas x The system comprises a heat exchange device 1, a multifunctional oxidation layer 4, an SCR catalyst layer 5, and a tail end catalyst layer 6 which are sequentially arranged on a flue 7.

[0095] The multifunctional oxidation layer 4 is filled with a columnar carbon monoxide oxidation catalyst with a diameter of 5 mm. The multifunctional oxidation layer 4 is 30 cm thick and has an inclination angle of 10°. The multifunctional oxidation layer 4 is placed in an elastic metal mesh. A bracket 8 is provided at the bottom of the multifunctional oxidation layer 4. The other end of the bracket is connected to the inner wall of the flue 7 and can rotate around the fulcrum on the inner wall of the flue 7. Bolts 9 are provided above and below the elastic metal mesh; the SCR catalyst layer 5 is filled with a carbon monoxide SCR catalyst, and the tail catalyst layer 6 is filled with a 20 cm diameter 5 cm spherical carbon monoxide oxidation catalyst.

[0096] The test sintering flue gas components used are: water content 10%, carbon monoxide content 6500ppm, nitrogen oxide content 200ppm, flue gas flow rate 3000m 3 / h, starting temperature 130℃, and rising to 200℃ through heat exchanger 1.

[0097] like Figure 4 As shown, the flue gas after heating enters the multifunctional oxidation layer 4, and the carbon monoxide removal rate at the outlet of the multifunctional oxidation layer 4 is 50%; before the flue gas enters the SCR catalyst layer 5, the flow rate Cv value is 13.1%, the temperature is 201°C, the nitrogen oxide removal rate at the outlet of the SCR catalyst layer 5 is 88%, and the carbon monoxide removal rate is 100% after the flue gas passes through the tail catalyst layer 6, and enters the heat exchanger 1 to recover the waste heat and then be discharged cleanly.

[0098] Embodiment 11

[0099] A method for simultaneously removing CO and NO from sintering flue gasx The system comprises a heat exchange device 1, a multifunctional oxidation layer 4, an SCR catalyst layer 5, and a tail end catalyst layer 6 which are sequentially arranged on a flue 7.

[0100] The multifunctional oxidation layer 4 is filled with a columnar carbon monoxide oxidation catalyst with a diameter of 5 mm. The multifunctional oxidation layer 4 is 35 cm thick and has an inclination angle of 15°. The multifunctional oxidation layer 4 is placed in an elastic metal mesh. A bracket 8 is provided at the bottom of the multifunctional oxidation layer 4. The other end of the bracket is connected to the inner wall of the flue 7 and can rotate around the fulcrum on the inner wall of the flue 7. Bolts 9 are provided above and below the elastic metal mesh; the SCR catalyst layer 5 is filled with a carbon monoxide SCR catalyst, and the tail catalyst layer 6 is filled with a 20 cm diameter 5 cm spherical carbon monoxide oxidation catalyst.

[0101] The test sintering flue gas components used are: water content 10%, carbon monoxide content 6500ppm, nitrogen oxide content 200ppm, flue gas flow rate 3000m 3 / h, the starting temperature is 130℃, which is increased to 160℃ through heat exchanger 1.

[0102] The heated flue gas enters the multifunctional oxidation layer 4, and the carbon monoxide removal rate at the outlet of the multifunctional oxidation layer 4 is 44%; before the flue gas enters the SCR catalyst layer 5, the flow rate Cv value is 13.5%, the temperature is 197°C, the nitrogen oxide removal rate at the outlet of the SCR catalyst layer 5 is 89%, and the carbon monoxide removal rate is 100% after the flue gas passes through the tail catalyst layer 6. After entering the heat exchanger 1 to recover the waste heat, it is discharged cleanly.

[0103] Example 12

[0104] A method for simultaneously removing CO and NO from sintering flue gas x The system comprises a heat exchange device 1, a multifunctional oxidation layer 4, an SCR catalyst layer 5, and a tail end catalyst layer 6 which are sequentially arranged on a flue 7.

[0105] The multifunctional oxidation layer 4 is filled with a columnar carbon monoxide oxidation catalyst with a diameter of 5 mm. The multifunctional oxidation layer 4 is 35 cm thick and has an inclination angle of 15°. The multifunctional oxidation layer 4 is placed in an elastic metal mesh. A bracket 8 is provided at the bottom of the multifunctional oxidation layer 4. The other end of the bracket is connected to the inner wall of the flue 7 and can rotate around the fulcrum on the inner wall of the flue 7. Bolts 9 are provided above and below the elastic metal mesh; the SCR catalyst layer 5 is filled with a carbon monoxide SCR catalyst, and the tail catalyst layer 6 is filled with a 20 cm diameter 5 cm spherical carbon monoxide oxidation catalyst.

[0106] The test sintering flue gas components used are: water content 10%, carbon monoxide content 6500ppm, nitrogen oxide content 200ppm, flue gas flow rate 3000m 3 / h, the starting temperature is 130℃, which is increased to 180℃ through heat exchanger 1.

[0107] The heated flue gas enters the multifunctional oxidation layer 4, and the carbon monoxide removal rate at the outlet of the multifunctional oxidation layer 4 is 47%; before the flue gas enters the SCR catalyst layer 5, the flow rate Cv value is 13.3%, the temperature is 199°C, the nitrogen oxide removal rate at the outlet of the SCR catalyst layer 5 is 87%, and the carbon monoxide removal rate is 100% after the flue gas passes through the tail catalyst layer 6. After entering the heat exchanger 1 to recover the waste heat, it is discharged cleanly.

[0108] It can be seen from Examples 1-4 that the oxidation efficiency is high when the primary oxidation layer uses a honeycomb carbon monoxide catalyst with a larger surface area, and the subsequent SCR denitrification effect is better when the multifunctional oxidation layer uses a multifunctional catalyst.

[0109] It can be seen from Examples 1, 5 and 6 that when the flue gas flow rate is large, properly adjusting the inclination angle and thickness of the multifunctional oxidation layer can still achieve a good rectifying effect on the flue gas entering the SCR catalyst layer.

[0110] It can be seen from Examples 6-8 that when the preheating of the heat exchange device is low, the oxidation efficiency of the primary oxidation layer is low, but after the primary oxidation layer and the multifunctional oxidation layer release heat for the two-stage oxidation of CO in the flue gas, the final CO and NO in the system x The removal rate can still achieve satisfactory results.

[0111] It can be seen from Example 9 that when the number of primary oxidation layer catalysts is reduced, after two-stage oxidation in the primary oxidation layer and the multifunctional oxidation layer, the CO contained in the flue gas itself can retain a reasonable proportion as a reducing agent for denitrification, and cooperate with the SCR catalyst layer to reduce nitrogen oxides. The final CO and NO in the entire system x The removal rate can still achieve satisfactory results.

[0112] It can be seen from Examples 10-12 that by reasonably setting the thickness and inclination angle of the multifunctional oxidation layer according to the initial components of the flue gas, not only can CO be oxidized to increase the flue gas temperature, but also a reasonable proportion of CO in the flue gas can be retained as a reducing agent for denitrification, and the SCR catalyst layer can be used to reduce nitrogen oxides. Using the CO contained in the flue gas itself as a reducing agent can not only save the reducing agent ammonia used in the conventional NH3-SCR method, but also simplify the reaction device without installing an ammonia injection device. The final CO and NO of the entire system x The removal rate can still achieve satisfactory results.

[0113] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

[0114] In addition, those skilled in the art will appreciate that, although some embodiments herein include certain features included in other embodiments but not other features, the combination of features of different embodiments is meant to be within the scope of the present invention and to form different embodiments. For example, in the above claims, any one of the claimed embodiments may be used in any combination. The information disclosed in this background technology section is intended only to deepen the understanding of the overall background technology of the present invention and should not be regarded as an admission or in any form of implication that the information constitutes prior art known to those skilled in the art.

Claims

1. A method for simultaneously removing CO and NO from sintering flue gas x A system, characterized in that It comprises a multifunctional oxidation layer and an SCR catalyst layer which are sequentially arranged on a flue; a heat exchange device is connected between the flue upstream of the multifunctional oxidation layer and the flue downstream of the SCR catalyst layer, for heat exchange between the flue upstream of the multifunctional oxidation layer and the flue downstream of the SCR catalyst layer; A primary oxidation layer is also provided on the flue between the multifunctional oxidation layer and the heat exchange device; The primary oxidation layer is a honeycomb / plate oxidation layer, which contains a honeycomb carbon monoxide oxidation catalyst or a plate carbon monoxide oxidation catalyst; the multifunctional oxidation layer is a particle oxidation layer, which contains a spherical carbon monoxide oxidation catalyst, a columnar carbon monoxide oxidation catalyst or a multifunctional catalyst, and the multifunctional catalyst can oxidize CO and promote the oxidation of NO to NO2; the SCR catalyst layer contains an ammonia SCR catalyst or a carbon monoxide SCR catalyst; The system further comprises an ammonia injection device disposed on the flue between the primary oxidation layer and the multifunctional oxidation layer; The system further comprises a tail end catalyst layer disposed on the flue between the SCR catalyst layer and the heat exchange device; the tail end catalyst layer is provided with a carbon monoxide oxidation catalyst; The multifunctional oxidation layer has an inclination angle of one side being thinner and the other side being thicker, which changes with the curvature of the flue or changes itself, and the inclination angle and the average thickness of the multifunctional oxidation layer are both adjustable; The multifunctional oxide layer is placed in the elastic metal wire mesh, a bracket is arranged at the bottom of the multifunctional oxide layer, the other end of the bracket is connected to the inner wall of the flue, the bracket can rotate around the fulcrum on the inner wall of the flue, and the rotation of the bracket can adjust the inclination angle of the multifunctional oxide layer; Bolts are arranged above and below the elastic metal wire mesh, and the thickness of the elastic metal wire mesh can be adjusted by the bolts, so that the inner catalyst of the multifunctional oxidation layer installed in the elastic metal wire mesh becomes tight or loose.

2. The system according to claim 1, characterized in that The tilt angle is 0-15 o The average thickness of the multifunctional oxide layer is 20-35 cm.

3. A system based on any one of claims 1-2 for simultaneously removing CO and NO from sintering flue gas x The method is characterized in that The steps include: S1: The flue gas is heated by the heat exchange device; S4: The heated flue gas enters the multifunctional oxidation layer, where CO oxidation releases heat to increase the flue gas temperature and promotes oxidation of NO in the flue gas to NO2. At the same time, the thickness and inclination angle of the multifunctional oxidation layer are adjusted to make the gas concentration and flow rate more balanced. S5: After passing through the multifunctional oxidation layer, the flue gas enters the SCR catalyst layer for denitration reaction; S7: The flue gas after denitrification is recovered through the heat exchange device for waste heat recovery and then discharged cleanly.

4. The method according to claim 3, characterized in that Step S2 and / or step S3 are also included between steps S1 and S4. Step S2 is: the flue gas heated by the heat exchange device enters the primary oxidation layer to oxidize CO and increase the flue gas temperature at the same time; step S3 is: the heated flue gas is mixed with the ammonia injected by the ammonia injection device.

5. The method according to claim 3, characterized in that: The step S6 is also included between the steps S5 and S7. The step S6 is: the flue gas after denitration enters the tail end catalyst layer to be thoroughly oxidized by CO.

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