Combined removal system for NOx and CO in sintering machine flue gas

Abstract

The utility model discloses a combined removal system for NOx and CO in flue gas of a sintering machine. The combined removal system comprises a desulfurization unit, a dust remover, a hot blast stove, a CO-SCR reactor, a CO oxidation reactor and a chimney which are sequentially connected through pipelines, the CO-SCR reactor comprises a reactor body I, the reactor body I is connected with a gas inlet pipeline I and a gas outlet pipeline I, and a plurality of CO-SCR catalyst bed layers are arranged in the reactor body I up and down; the CO oxidation reactor comprises a reactor body II, the reactor body II is connected with an air inlet pipeline II and an air outlet pipeline II, an air uniform distributor is arranged on the air inlet pipeline II, the air uniform distributor is connected with an air inlet pipe, an electric heater is arranged on the air inlet pipe, and a plurality of CO oxidation catalyst bed layers are arranged in the reactor body II up and down. The device not only can eliminate NOx and CO at the same time, but also can avoid secondary pollution caused by introduction of reducing agents such as NH3 and the like.

Description

Technical Field

[0001] The utility model relates to the technical field of flue gas purification, and in particular to a method for removing NO from sintering machine flue gas. x Combined removal system for CO and CO. Background Art

[0002] Iron ore sintering is the first raw material processing step in steel production, and its flue gas pollutant emissions account for a relatively high proportion. In recent years, the emission standards for sintering flue gas pollutants have been updated one after another, and the most stringent ultra-low emission standards in history have been introduced: NO x <50mg / Nm 3 , SO 2 <35mg / Nm 3 , particulate matter <10mg / Nm 3 , dioxin<0.5mg / Nm 3 Therefore, the research and application of ultra-low emission technology of sintering machine flue gas is of great significance to improving the quality of the atmospheric environment and promoting the transformation and upgrading of steel enterprises. Another pollutant produced during the sintering process of the sintering machine is CO. At present, with the emphasis on environmental protection, the emission of CO is becoming more and more stringent.

[0003] In the sintering machine flue gas, nitrogen oxides (NO x ) concentration is usually 150-500mg / m 3 The CO concentration is usually between 3000-6000 mg / m 3 At present, the removal of nitrogen oxides usually uses NH 3 -SCR method, but this method has NH 3 There are many disadvantages, such as leakage, corrosion of equipment, and blockage of pipelines by the byproduct ammonium bisulfate. 3 -The problems of SCR method need to develop a new method to remove NO in sintering machine flue gas at the same time x and CO methods to solve the above problems. Utility Model Content

[0004] The technical problem to be solved by the utility model is to overcome the shortcomings of the prior art and provide a method for removing NO in sintering machine flue gas. x The combined removal system of CO and flue gas uses CO in flue gas as a reducing agent to reduce NO in flue gas. x The reaction can not only eliminate NO x and CO, achieving CO and NO x The reduction of emissions also reduces costs, saves resources, and avoids the introduction of NH 3 Secondary pollution caused by reducing agents.

[0005] The technical solution of the utility model is:

[0006] Used for NO in sintering machine flue gas x The invention discloses a combined removal system of CO and CO, comprising a desulfurization unit, a dust collector, a hot blast furnace, a CO-SCR reactor, a CO oxidation reactor and a chimney which are sequentially connected through pipelines; the CO-SCR reactor comprises a reactor body 1, the reactor body 1 is connected with an air inlet pipe 1 and an air outlet pipe 1, and a plurality of CO-SCR catalyst beds are arranged in the reactor body 1; the CO oxidation reactor comprises a reactor body 2, the reactor body 2 is connected with an air inlet pipe 2 and an air outlet pipe 2, an air distributor is arranged on the air inlet pipe 2, the air distributor is connected with an air inlet pipe, an electric heater is arranged on the air inlet pipe, and a plurality of CO oxidation catalyst beds are arranged in the reactor body 2.

[0007] Preferably, the air distributor comprises a main pipe connected to the air inlet pipe, a plurality of branch pipes are connected to the main pipe, and a plurality of nozzles are arranged on the branch pipes.

[0008] Preferably, the air inlet duct is provided with flow guide components at the air inlet end and the air outlet end respectively, and the flow guide components include a plurality of flow guide plates.

[0009] Preferably, a static mixer is provided in the air intake duct 1 between the two flow guide components.

[0010] Preferably, a static mixer is provided in the second air intake duct below the air distributor.

[0011] Preferably, the static mixer comprises a plurality of rows of inclined plates arranged obliquely, and the inclined directions of two adjacent rows of inclined plates are opposite.

[0012] Preferably, the pipeline between the dust collector and the hot blast stove and the pipeline between the CO oxidation reactor and the chimney are connected with a heat exchanger.

[0013] Preferably, a fan is provided on the pipeline between the CO oxidation reactor and the chimney.

[0014] Preferably, a valve and a fan are provided on the air intake pipe.

[0015] Compared with the prior art, the utility model has the following beneficial effects:

[0016] The utility model NO x The combined removal system uses CO in the flue gas as a reducing agent to reduce NO in the flue gas. x The reaction can not only eliminate NO x and CO, achieving CO and NO x The reduction of emissions also reduces costs, saves resources, and avoids the introduction of NH 3Secondary pollution caused by reducing agents. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The utility model is used for NO in sintering machine flue gas x Schematic diagram of the structure of the combined removal system of CO and CO.

[0018] Figure 2 It is a structural schematic diagram of the CO-SCR reactor of the utility model.

[0019] Figure 3 It is a structural schematic diagram of a flow guide component at the air intake end of an air intake duct 1 of the utility model.

[0020] Figure 4 It is a structural schematic diagram of a CO oxidation reactor of the utility model.

[0021] Figure 5 It is a structural schematic diagram of the static mixer of the utility model.

[0022] Figure 6 It is a structural schematic diagram of the air distributor of the utility model.

[0023] In the figure, 1. desulfurization unit; 2. dust collector; 3. hot air furnace; 4. CO-SCR reactor; 401. reactor body 1; 402. air inlet pipe 1; 403. air outlet pipe 1; 404. CO-SCR catalyst bed; 405. guide assembly; 4051. guide plate; 406. flue gas distributor; 5. CO oxidation reactor; 501. reactor body 2; 502. air inlet pipe 2; 503. air outlet pipe 2; 504. air distributor; 5041. main pipe; 5042. branch pipe; 5043. nozzle; 505. air inlet pipe; 506. electric heater; 507. CO oxidation catalyst bed; 6. chimney; 7. static mixer; 701. inclined plate; 8. heat exchanger; 9. fan; 10. valve; 11. sintering machine. DETAILED DESCRIPTION

[0024] In order to enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention.

[0025] Example 1

[0026] like Figure 1 As shown, this embodiment provides a method for removing NO from sintering machine flue gas. xThe combined removal system of CO and CO comprises a desulfurization unit 1, a dust collector 2, a hot blast furnace 3, a CO-SCR reactor 4, a CO oxidation reactor 5 and a chimney 6 which are sequentially connected through pipelines, and a fan 9 is arranged on the pipeline between the CO oxidation reactor 5 and the chimney 6. The desulfurization unit 1 adopts SDA semi-dry desulfurization, which is a prior art and will not be described in detail here.

[0027] Specifically, Figure 2 As shown, in this embodiment, the CO-SCR reactor 4 includes a reactor body 401, the reactor body 401 is connected to an air inlet pipe 402 and an air outlet pipe 403, and three CO-SCR catalyst beds 404 are arranged in the reactor body 401, and Mn / TiO 2 Manganese based catalyst.

[0028] At the same time, if Figure 4 As shown, the CO oxidation reactor 5 includes a second reactor body 501, the second reactor body 501 is connected to an air inlet pipe 502 and an air outlet pipe 503, an air distributor 504 is arranged on the second air inlet pipe 502, the air distributor 504 is connected to an air inlet pipe 505, an electric heater 506, a valve 10 and a fan 9 are arranged on the air inlet pipe 505, and three CO oxidation catalyst beds 507 are arranged in the second reactor body 501, and Pt / TiO 2 Precious metal catalyst. The function of the air distributor 504 is to evenly distribute the air entering the air inlet pipe 505 in the CO oxidation reactor 5, so that the air can fully contact the CO oxidation catalyst below, which is conducive to the full progress of the reaction and improves the CO oxidation efficiency. Specifically, Figure 6 As shown, the air uniform distributor 504 includes a main pipe 5041 connected to an air inlet pipe 505, a plurality of branch pipes 5042 are connected to the main pipe 5041, and a plurality of nozzles 5043 are arranged on the branch pipes 5042. Air enters the main pipe 5041 from the air inlet pipe 505 under the action of the fan 9, and then is uniformly sprayed into the CO oxidation reactor 5 through the nozzles 5043 on each branch pipe 5042, thereby achieving the purpose of uniform air distribution.

[0029] Working principle:

[0030] The flue gas from the sintering machine 11 is first desulfurized by the desulfurization unit 1 and then dedusted by the dust collector 2. It then enters the hot air furnace 3 and is heated to 200-350°C. It then enters the CO-SCR reactor 4. Under the catalytic action of the CO-SCR catalyst, NO in the flue gas is removed. x Reacts chemically with CO to eliminate NO in flue gas x and some CO; and because the concentration of CO in flue gas is much higher than that of NOx concentration, the remaining CO enters the next CO oxidation reactor 5 equipped with a CO oxidation catalyst to undergo CO oxidation reaction. 2 The higher the concentration, the more conducive it is to the CO oxidation reaction. Therefore, under the action of the fan 9, fresh air is introduced into the CO oxidation reactor 5 through the air intake pipe 505 and the air distributor 504 to promote the elimination of CO. Finally, NO x The flue gas containing CO is then discharged through the chimney 6 under the action of the fan 9.

[0031] The utility model NO x The combined removal system uses CO in the flue gas as a reducing agent to reduce NO in the flue gas. x The reaction can not only eliminate NO x and CO, achieving CO and NO x The reduction of emissions also reduces costs, saves resources, and avoids the introduction of NH 3 Secondary pollution caused by reducing agents.

[0032] Example 2

[0033] On the basis of Example 1, Figure 2 As shown, the air inlet pipe 402 is provided with a guide assembly 405 at the air inlet end and the air outlet end, and the guide assembly 405 includes a plurality of guide plates 4051. Figure 3 As shown, the guide plate 4051 at the air inlet end is a plurality of vertical plates arranged along the width direction of the air inlet duct 402, which can make the smoke evenly distributed in the width direction of the air inlet duct 402; Figure 2 As shown, the guide plate 4051 at the gas outlet is a plurality of arc plates arranged up and down, which guide the flue gas to the CO-SCR catalyst bed 404 in the reactor body 401. Figure 2 As shown, a flue gas distributor 406 can also be arranged above the CO-SCR catalyst bed 404 in the reactor body 501. The flue gas distributor 406 is a frame with multiple layers of rectangular grids, so that after the flue gas is introduced into the reactor body 401 through the guide plate 4051, it can be evenly distributed on the CO-SCR catalyst bed 404, so that NO in the flue gas x The CO can fully react with the catalyst under the catalytic action to improve the removal efficiency.

[0034] Example 3

[0035] On the basis of Example 1, Figure 2 , 4As shown, a static mixer 7 is provided between two flow guide components 405 in the air intake duct 1 402, and a static mixer 7 is also provided below the air distributor 504 in the air intake duct 2 502. Figure 5 As shown, the static mixer 7 includes several rows of inclined plates 701, and the inclined directions of two adjacent rows of inclined plates 701 are opposite, so that the multiple rows of inclined plates 701 are arranged crosswise. When the flue gas flows through the static mixer 7 in the air intake duct 1 402, it will flow in a staggered manner under the guidance of the cross-arranged inclined plates 701, so that the flue gas is more evenly distributed in the air intake duct 1 402. At the same time, after the air is dispersed into the reactor body 2 501 by the air distributor 504, it flows through the static mixer 7 together with the flue gas, and the two will also flow in a staggered manner under the guidance of the cross-arranged inclined plates 701, so that the flue gas and air are evenly mixed in the reactor body 2 501, so that the oxidation reaction of CO is more fully carried out.

[0036] Example 4

[0037] On the basis of Example 1, Figure 1 As shown, the pipeline between the dust collector 2 and the hot blast stove 3 and the pipeline between the CO oxidation reactor 5 and the chimney 6 are connected with a heat exchanger 8. Before the low-temperature flue gas after dust removal by the dust collector 2 enters the hot blast stove 3 for heating, it first exchanges heat with the flue gas (temperature is 150-300°C) treated by the CO oxidation reactor 5, thereby preheating the flue gas before entering the hot blast stove 3, reducing the energy consumption of the hot blast stove 3, and also recycling the heat of the flue gas before the flue gas is discharged, reducing energy waste.

Claims

1. Used for NO in sintering machine flue gas x and CO combined removal system, characterized in that: The invention comprises a desulfurization unit (1), a dust collector (2), a hot blast furnace (3), a CO-SCR reactor (4), a CO oxidation reactor (5) and a chimney (6) which are connected in sequence through pipelines; the CO-SCR reactor (4) comprises a reactor body (401), the reactor body (401) is connected to an air inlet pipe (402) and an air outlet pipe (403), and a plurality of CO-SCR catalyst beds (404) are arranged in the reactor body (401) from top to bottom; the CO oxidation reactor (4) comprises a reactor body (401), the reactor body (401) is connected to an air inlet pipe (402) and an air outlet pipe (403), and a plurality of CO-SCR catalyst beds (404) are arranged in the reactor body (401); The chemical reactor (5) comprises a second reactor body (501), the second reactor body (501) is connected to a second air inlet pipe (502) and a second air outlet pipe (503), an air distributor (504) is arranged on the second air inlet pipe (502), the air distributor (504) is connected to an air inlet pipe (505), an electric heater (506) is arranged on the air inlet pipe (505), and a plurality of CO oxidation catalyst beds (507) are arranged above and below in the second reactor body (501).

2. The method for treating NO in sintering machine flue gas according to claim 1. x and CO combined removal system, characterized in that: The air distributor (504) comprises a main pipe (5041) connected to the air intake pipe (505), a plurality of branch pipes (5042) are connected to the main pipe (5041), and a plurality of nozzles (5043) are arranged on the branch pipes (5042).

3. The method for treating NO in sintering machine flue gas according to claim 1. x and CO combined removal system, characterized in that: The air inlet pipe (402) is provided with flow guide components (405) at the air inlet end and the air outlet end, respectively. The flow guide components (405) include a plurality of flow guide plates (4051).

4. The method for treating NO in sintering machine flue gas as claimed in claim 3 x and CO combined removal system, characterized in that: A static mixer (7) is provided in the air intake duct (402) between the two flow guide components (405).

5. The method for treating NO in sintering machine flue gas as claimed in claim 4 x and CO combined removal system, characterized in that: A static mixer (7) is provided in the second air intake duct (502) below the air distributor (504).

6. The method for treating NO in sintering machine flue gas according to claim 4 or 5. x and CO combined removal system, characterized in that: The static mixer (7) comprises a plurality of rows of inclined plates (701) arranged obliquely, and the inclined directions of two adjacent rows of inclined plates (701) are opposite.

7. The method for treating NO in sintering machine flue gas as claimed in claim 1. x and CO combined removal system, characterized in that: The pipeline between the dust collector (2) and the hot blast furnace (3) and the pipeline between the CO oxidation reactor (5) and the chimney (6) are connected to a heat exchanger (8).

8. The method for treating NO in sintering machine flue gas according to claim 1 x and CO combined removal system, characterized in that: A fan (9) is provided on the pipeline between the CO oxidation reactor (5) and the chimney (6).

9. The method for treating NO in sintering machine flue gas as claimed in claim 1 x and CO combined removal system, characterized in that: The air intake pipe (505) is provided with a valve (10) and a fan (9).

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