Device and method for recycling coke oven flue gas denitration catalyst thermal desorption flue gas

Abstract

The invention relates to the technical field of coking environmental protection, in particular to a device and a method for recycling coke oven flue gas denitration catalyst thermal desorption flue gas. The device comprises a flue gas denitration device; the flue gas denitration device is provided with an ammonia spraying pipeline and a flue gas heating pipeline in a matched manner; the heating flue gas pipeline is connected with the hot-blast stove; the coke oven flue gas outlet main pipe is connected with a coke oven flue gas outlet of the flue gas denitration device; the desorbed flue gas outlet pipeline is connected with a desorbed flue gas outlet of the flue gas denitration device; the booster fan is connected with a flue gas outlet of the analyzed flue gas collecting pipeline; a gas outlet pipeline of the booster fan is connected with a coke oven flue gas inlet main pipe through a pipeline interface; a desulfurizing agent spraying inlet is formed in a pipeline joint of the coke oven flue gas inlet main pipe; the cloth bag dust removal bin is connected with a flue gas outlet of the coke oven flue gas inlet main pipe; and a flue gas outlet of the cloth bag dust removal bin is connected with a flue gas inlet of the flue gas denitration device. According to the invention, thoroughness of thermal desorption is ensured, catalyst activity recovery is good, and denitration efficiency is high.

Description

Technical Field

[0001] The invention relates to the technical field of coking environmental protection, and in particular to a device and method for recycling flue gas from thermal denitration catalyst of coke oven flue gas. Background Art

[0002] In the coke oven production, the exhaust gas (flue gas) generated by the coke oven heating contains harmful substances such as SO2, NOx, and dust. The existing technology generally uses sodium bicarbonate to remove SO2; the flue gas after removal is passed through a bag filter to remove dust particles, etc.; then ammonia vapor is sprayed in, and under the action of vanadium-based catalyst, ammonia reacts with NOx to generate N2. The purified coke oven flue gas is sent to the chimney through an exhaust fan to meet the emission standards (SO2≤30mg / m 3 、NOx≤150mg / m 3 、Particulate matter ≤10mg / m 3 , NH3≤2.5ppm).

[0003] During the long-term use of the coke oven flue gas denitration catalyst, the injected ammonia will react with SO2 to form ammonium bisulfate. Ammonium bisulfate is a high-viscosity substance that adheres to the dust in the flue gas, blocking the catalyst surface, reducing the catalyst activity, and denitration efficiency, making the flue gas outlet NOx substandard. For this reason, 320-380℃ hot air is used to heat the denitration catalyst, so that the ammonium bisulfate is decomposed into SO3 and NH3 under high temperature, thereby improving the catalytic capacity of the denitration catalyst. However, the particulate matter released during the analysis will enter the chimney with the exhaust fan, causing the particulate matter in the chimney exhaust gas to exceed the standard, the thermal analysis is not thorough, the catalyst activity is not well restored, and the denitration efficiency is still low. Summary of the invention

[0004] In view of this, the technical problem to be solved by the present invention is to provide a device and method for recycling flue gas by thermal analysis of denitration catalyst of coke oven flue gas. The device and method provided by the present invention ensure the thoroughness of thermal analysis, good recovery of catalyst activity and high denitration efficiency.

[0005] The present invention provides a device for recycling flue gas by thermal desorption of a denitration catalyst of coke oven flue gas, comprising:

[0006] A flue gas denitration device; the flue gas denitration device is equipped with an ammonia spraying pipeline and a flue gas heating pipeline; the flue gas heating pipeline is connected to the hot blast furnace;

[0007] A coke oven flue gas outlet main pipe connected to the coke oven flue gas outlet of the flue gas denitration device;

[0008] A deionized flue gas outlet pipe connected to the deionized flue gas outlet of the flue gas denitrification device;

[0009] A booster fan connected to the smoke outlet of the analyzed smoke collection duct;

[0010] The outlet pipe of the booster fan is connected to the coke oven smoke inlet main pipe through a pipe interface; a desulfurizing agent injection port is arranged at the pipe interface of the coke oven smoke inlet main pipe;

[0011] A bag dust removal bin is connected to the flue gas outlet of the coke oven flue gas inlet main pipe; the flue gas outlet of the bag dust removal bin is connected to the flue gas inlet of the flue gas denitrification device.

[0012] Preferably, the decomposed flue gas outlet is arranged at the top of the flue gas denitrification device;

[0013] A first valve is arranged on the pipeline between the analytical flue gas outlet pipeline and the flue gas denitration device.

[0014] Preferably, the booster fan is provided with a second valve.

[0015] Preferably, a third valve is provided at the pipe interface of the air outlet pipe of the booster fan.

[0016] Preferably, a denitration catalyst layer is provided in the flue gas denitration device.

[0017] Preferably, the flue gas denitration device is provided with an ammonia injection port, and the ammonia injection port is connected to the ammonia injection pipeline; an ammonia injection valve is provided on the ammonia injection port.

[0018] Preferably, a coke oven flue gas outlet valve is provided at the coke oven flue gas outlet of the flue gas denitrification device.

[0019] Preferably, the device further comprises:

[0020] A main exhaust fan connected to the flue gas outlet of the coke oven flue gas outlet main pipe;

[0021] and a coke oven chimney connected to the smoke outlet of the main exhaust fan.

[0022] The present invention also provides a method for recycling flue gas from thermal decomposition of a coke oven flue gas denitration catalyst, comprising the following steps:

[0023] A) selecting a denitration catalyst in a denitration bin of a flue gas denitration device for heating and decomposition;

[0024] B) collecting the analyzed flue gas after the heating analysis to the analyzed flue gas outlet pipe;

[0025] C) the desulfurized flue gas in the desulfurized flue gas outlet pipe is transported to the coke oven flue gas inlet main pipe through a booster fan for desulfurization;

[0026] D) the desulfurized flue gas enters the bag dust removal bin for dust removal;

[0027] E) The flue gas after dust removal enters the non-analytical denitrification bin in the flue gas denitrification device for denitrification, and the flue gas after denitrification is discharged externally.

[0028] Preferably, the temperature of the heating analysis is 320-380°C.

[0029] The present invention provides a device for recycling flue gas by thermal analysis of a coke oven flue gas denitration catalyst, comprising: a flue gas denitration device; the flue gas denitration device is equipped with an ammonia injection pipeline and a heating flue gas pipeline; the heating flue gas pipeline is connected to a hot blast furnace; a coke oven flue gas outlet main pipe connected to the coke oven flue gas outlet of the flue gas denitration device; a decomposition flue gas outlet pipeline connected to the decomposition flue gas outlet of the flue gas denitration device; a booster fan connected to the flue gas outlet of the decomposition flue gas collection pipeline; the air outlet pipeline of the booster fan is connected to the coke oven flue gas inlet main pipe through a pipeline interface; a desulfurizer injection port is arranged at the pipeline interface of the coke oven flue gas inlet main pipe; a bag dust removal bin is connected to the flue gas outlet of the coke oven flue gas inlet main pipe; the flue gas outlet of the bag dust removal bin is connected to the flue gas inlet of the flue gas denitration device. The present invention collects the high-temperature flue gas during pyrolysis by a pipeline, uses a booster fan, and transports it to the entrance of the bag dust removal bin after desulfurization, and desulfurizes and removes dust again for reuse, thereby ensuring the thoroughness of thermal analysis, good catalyst activity recovery, and high denitrification efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A diagram of a device for recycling flue gas by thermal decomposition of a denitration catalyst for coke oven flue gas provided in one embodiment of the present invention;

[0031] Figure 2 This is the process flow chart of desulfurization and denitrification of coke oven flue gas;

[0032] Figure 3 This is a process flow chart of thermal desorption of denitration catalyst according to Example 2 of the present invention;

[0033] Figure 4 This is a process flow chart of thermal analysis of the denitration catalyst of Comparative Example 1. DETAILED DESCRIPTION

[0034] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] The present invention provides a device for recycling flue gas by thermal desorption of a denitration catalyst of coke oven flue gas, comprising:

[0036] A flue gas denitration device; the flue gas denitration device is equipped with an ammonia spraying pipeline and a flue gas heating pipeline; the flue gas heating pipeline is connected to the hot blast furnace;

[0037] A coke oven flue gas outlet main pipe connected to the coke oven flue gas outlet of the flue gas denitration device;

[0038] A deionized flue gas outlet pipe connected to the deionized flue gas outlet of the flue gas denitrification device;

[0039] A booster fan connected to the smoke outlet of the analyzed smoke collection duct;

[0040] The outlet pipe of the booster fan is connected to the coke oven smoke inlet main pipe through a pipe interface; a desulfurizing agent injection port is arranged at the pipe interface of the coke oven smoke inlet main pipe;

[0041] A bag dust removal bin is connected to the flue gas outlet of the coke oven flue gas inlet main pipe; the flue gas outlet of the bag dust removal bin is connected to the flue gas inlet of the flue gas denitrification device.

[0042] Figure 1 A diagram of a device for recycling flue gas by thermal desorption of denitrification catalyst of coke oven flue gas provided by an embodiment of the present invention. 1 is a flue gas denitrification device; 1-1 is a denitrification catalyst layer; 2 is an ammonia injection pipeline; 3 is a heating flue gas pipeline; 4 is a hot blast stove; 5 is a coke oven flue gas outlet main pipe; 6 is a main exhaust fan; 7 is a coke oven chimney; 8 is a first valve; 9 is a desorption flue gas outlet pipe; 10 is a booster fan; 11 is a second valve; 12 is a third valve; 13 is a pipeline interface; 14 is a coke oven flue gas inlet main pipe; 15 is a desulfurizer injection inlet; 16 is a fourth valve; 17 is a bag dust removal bin.

[0043] The flue gas denitration device 1 is provided with a denitration catalyst layer 1 - 1 , and the denitration catalyst layer 1 - 1 is filled with a denitration catalyst, specifically a vanadium-based catalyst.

[0044] The flue gas denitration device 1 is equipped with an ammonia injection pipeline 2 and a flue gas heating pipeline 4. The flue gas denitration device 1 is provided with an ammonia injection port, and the ammonia injection port is connected to the ammonia injection pipeline 2. The ammonia injection pipeline 2 injects ammonia vapor into the flue gas denitration device 1 through the ammonia injection port. An ammonia injection valve is provided on the ammonia injection port.

[0045] The heating flue gas pipeline 4 is connected to the hot blast furnace and is used to heat the flue gas entering the flue gas denitration device 1. A hot flue gas valve is arranged at the pipeline where the heating flue gas pipeline 4 is connected to the flue gas denitration device 1.

[0046] In certain embodiments of the present invention, the flue gas denitrification device 1 is a denitrification bin.

[0047] The device provided by the present invention also includes a coke oven flue gas outlet main pipe 5 connected to the coke oven flue gas outlet of the flue gas denitrification device 1. The coke oven flue gas outlet of the flue gas denitrification device 1 is arranged on the upper part of the denitrification catalyst layer 1-1. A coke oven flue gas outlet valve is arranged at the coke oven flue gas outlet of the flue gas denitrification device 1. The coke oven flue gas outlet main pipe 5 is used to discharge the flue gas after denitrification. The device provided by the present invention also includes:

[0048] A main exhaust fan 6 connected to the flue gas outlet of the coke oven flue gas outlet main pipe 5;

[0049] And a coke oven chimney 7 connected to the smoke outlet of the main exhaust fan 6.

[0050] The denitrified flue gas in the flue gas denitrification device 1 is transported to the coke oven chimney 7 through the main exhaust fan 6 and then discharged.

[0051] The device provided by the present invention further comprises a desorption flue gas outlet pipe 9 connected to the desorption flue gas outlet of the flue gas denitrification device 1. The desorption flue gas outlet is arranged at the top of the flue gas denitrification device.

[0052] A first valve 8 is provided on the pipe (interface pipe) between the analytical flue gas outlet pipe 9 and the flue gas denitrification device 1. In certain embodiments of the present invention, the pipe diameter between the analytical flue gas outlet pipe 9 and the flue gas denitrification device 1 is 380-420 mm, such as 400 mm; the material is carbon steel, and the external rock wool board of 80-120 mm (such as 100 mm) is used for heat insulation to prevent burns. The first valve 8 is a manual butterfly valve, and the material temperature resistance is not less than 500°C.

[0053] In certain embodiments of the present invention, the number of the flue gas denitrification devices 1 is multiple, such as ≥2, specifically 7. Each flue gas denitrification device corresponds to an interface pipe, and each interface pipe is matched with a first valve (manual butterfly valve). The decomposed flue gas outlet of each flue gas denitrification device is connected to the decomposed flue gas outlet pipe 9 through its own interface pipe. Each flue gas denitrification device is provided with an ammonia injection port, which is matched with an ammonia injection valve. Each flue gas denitrification device is matched with a hot flue gas valve.

[0054] In certain embodiments of the present invention, the material of the analytical flue gas outlet pipe 9 is carbon steel, with a diameter of 380-420 mm, such as 400 mm; it is insulated with 80-120 mm (such as 100 mm) rock wool board and arranged along the top of the denitrification silo.

[0055] The device provided by the present invention also includes a booster fan 10 connected to the smoke outlet of the analyzed smoke collection pipe, and is provided with a second valve 11. The booster fan is used to provide the resistance that the analyzed smoke needs to overcome, and the fan operating flow rate is not less than 15,000 m 3 / h, full pressure 3~4KPa, with frequency conversion. The fan material is high temperature resistant, not less than 500℃; the attached second valve is used to adjust the pressure.

[0056] In the present invention, the air outlet pipe of the booster fan 10 is connected to the coke oven flue gas inlet main pipe 14 through a pipe interface; a desulfurizing agent injection port 15 is arranged at the pipe interface of the coke oven flue gas inlet main pipe 14.

[0057] A third valve 12 is provided at the pipe interface of the outlet pipe of the booster fan 10. It is used to transport the analyzed flue gas to the coke oven flue gas inlet main pipe through the booster fan 10. The diameter of the pipe interface is 380-420 mm, such as 400 mm; the material is carbon steel, and the external insulation is 80-120 mm (such as 100 mm) rock wool board. The third valve matches the pipeline and is a butterfly valve with a temperature resistance of 500°C.

[0058] The present invention further comprises a bag dust removal bin 17 connected to the flue gas outlet of the coke oven flue gas inlet main pipe 14 ; the flue gas outlet of the bag dust removal bin 17 is connected to the flue gas inlet of the flue gas denitrification device 1 .

[0059] A fourth valve 16 is provided on the flue gas outlet pipe of the coke oven flue gas inlet main pipe 14 .

[0060] In certain embodiments of the present invention, the bag dust removal bin 17 is matched with the flue gas denitration device 1, and the number of the bag dust removal bins 17 is the same as the number of the flue gas denitration device 1. The coke oven flue gas inlet main pipe 14 is matched with the bag dust removal bin 17, and the number of flue gas outlets of the coke oven flue gas inlet main pipe 14 is the same as the number of the bag dust removal bin 17. Each flue gas outlet is matched with a fourth valve.

[0061] The device provided by the present invention also includes a control system for starting, stopping and frequency conversion adjustment of the booster fan 10, and keeping the booster fan 10 interlocked with the hot blast furnace 4. When the booster fan 10 fails, the hot blast furnace 4 automatically cuts off the gas used for combustion to prevent explosion and ensure the safety of the equipment. The control system is a Siemens PLC.

[0062] The present invention also provides a method for recycling flue gas from thermal decomposition of a coke oven flue gas denitration catalyst using the above-mentioned device, comprising the following steps:

[0063] A) selecting a denitration catalyst in a denitration bin of a flue gas denitration device for heating and decomposition;

[0064] B) collecting the analyzed flue gas after the heating analysis to the analyzed flue gas outlet pipe;

[0065] C) the desulfurized flue gas in the desulfurized flue gas outlet pipe is transported to the coke oven flue gas inlet main pipe through a booster fan for desulfurization;

[0066] D) the desulfurized flue gas enters the bag dust removal bin for dust removal;

[0067] E) The flue gas after dust removal enters the non-analytical denitrification bin in the flue gas denitrification device for denitrification, and the flue gas after denitrification is discharged externally.

[0068] The method for desulfurizing and denitrifying coke oven flue gas using the device of the present invention comprises the following steps:

[0069] The coke oven flue gas (containing SO2, particulate matter, and NOx) is drawn out from the coke oven flue and enters the coke oven flue gas inlet main pipe 14. A high-efficiency dry desulfurizer (sodium bicarbonate, purity above 98%) is sprayed into the desulfurizer spray port 15. The desulfurizer is thermally activated in the flue and fully contacts the coke oven flue gas, undergoing physical and chemical reactions. The acidic substances such as SO2 in the flue gas are absorbed and purified. The powder-containing flue gas after absorbing SO2 enters the bag dust removal bin 17 for dust removal. The flue gas after removing particulate matter enters the flue gas denitrification device 1. The flue gas denitrification device 1 is filled with a denitrification catalyst layer 1-1. The NOx in the flue gas is mixed with the injected ammonia (NH3), and reacts chemically with NH3 under the action of the denitrification catalyst to generate N2 and H2O, thereby achieving the purpose of removing NOx in the flue gas. The clean flue gas is drawn by the main exhaust fan 6 and enters the coke oven chimney 7 to be discharged into the atmosphere.

[0070] In the present invention, during heating and analysis, it can only be carried out one bin at a time. For example, if there are 7 denitrification bins, only one of them can be analyzed, and the other 6 denitrifications are carried out normally, and the corresponding valves are also opened or closed independently. During denitrification, the fourth valve at the entrance of the bag dust removal bin is opened, the valve at the coke oven flue gas outlet on the bin top is opened, and the first valve of the corresponding flue gas denitrification device 1 (desnitrification bin) is closed. During analysis, the fourth valve at the entrance of the corresponding bag dust removal bin is closed, the valve at the coke oven flue gas outlet on the bin top is closed, and the first valve of the corresponding flue gas denitrification device (desnitrification bin) is opened. (See Figure 1 )

[0071] Specifically, when the denitration catalyst in a flue gas denitration device (denitrification bin) needs to be decomposed, first close the ammonia injection valve corresponding to the flue gas denitration device and the fourth valve at the entrance of the corresponding bag dust removal bin, so that the flue gas denitration device (decomposition denitration bin) is offline and in a denitration stop state. Close the coke oven flue gas outlet valve of the flue gas denitration device (decomposition denitration bin) so that the decomposed flue gas is no longer discharged to the coke oven chimney through the main exhaust fan.

[0072] Then, the first valve corresponding to the flue gas denitration device (analytical denitration bin) is opened, the first valves of other flue gas denitration devices (non-analytical denitration bins) are closed, and the third valve is opened.

[0073] Then turn on the booster fan, adjust the second valve and the motor frequency of the booster fan, so that the flue gas denitrification device (denitration chamber) and the hot air furnace maintain appropriate pressure. Among them, the pressure of the hot air furnace hall is guaranteed to be -600~-1000Pa. The pressure of the flue gas denitrification device (denitration chamber) is -1500~-2000Pa.

[0074] The hot blast furnace is turned on. The hot blast furnace burns coke oven gas or blast furnace gas to provide high-temperature flue gas for catalyst decomposition. By adjusting the fan frequency, hot flue gas flow rate and temperature, the high-temperature flue gas is kept at 320-380°C (i.e., the heating decomposition temperature) when it flows through the flue gas denitration device (denitration denitration bin), which can completely decompose the ammonium bisulfate bonded to the catalyst surface.

[0075] In certain embodiments of the present invention, the temperature of the heating desorption is 380° C. and the time is 45 to 55 hours, such as 48 hours.

[0076] After the analysis is completed, stop the hot blast furnace, stop the booster fan, and close the corresponding first valve, second valve, and third valve. Open the fourth valve at the entrance of the bag dust removal bin and the coke oven flue gas outlet valve of the flue gas denitrification device (analysis denitrification bin), open the ammonia injection valve, and restore the working state of the coke oven flue gas desulfurization and denitrification.

[0077] In the present invention, analysis is performed only when the denitration efficiency decreases, usually once every three months or six months; analysis and denitration are separate, and no denitration occurs during analysis. Specifically, the flue gas discharged from the flue gas outlet of the flue gas denitration device (the flue gas after denitration) is >130mg / m 3 , perform analysis.

[0078] Beneficial effects of the present invention:

[0079] The exhaust gas analyzed by the denitration catalyst is returned to the desulfurization and dust removal using the device and method of the present invention, and is no longer discharged through the chimney diameter, so that the SO2 and particulate matter generated during the analysis process can be purified again, thereby ensuring that the coke oven chimney meets the emission standards.

[0080] In order to further illustrate the present invention, a device and method for recycling flue gas by thermal desorption of denitrification catalyst of coke oven flue gas provided by the present invention are described in detail below in combination with embodiments, but it should not be understood as limiting the scope of protection of the present invention.

[0081] Example 1

[0082] Use Figure 1 The method for desulfurizing and denitrifying coke oven flue gas by the device shown in the figure comprises the following steps (process flow as shown in Figure 2 As shown, Figure 2 (Process flow chart for desulfurization and denitrification of coke oven flue gas):

[0083] The coke oven flue gas (containing SO2, particulate matter, and NOx) is drawn out from the coke oven flue and enters the coke oven flue gas inlet main pipe 14. A high-efficiency dry desulfurizer (sodium bicarbonate, purity above 98%) is sprayed into the desulfurizer spray port 15. The desulfurizer is thermally activated in the flue and fully contacts the coke oven flue gas, causing physical and chemical reactions. The acidic substances such as SO2 in the flue gas are absorbed and purified. The powdery flue gas after absorbing SO2 enters the bag dust removal bin 17 for dust removal, and the flue gas after removing particulate matter enters the flue gas denitrification device 1. The flue gas denitration device 1 is filled with a denitration catalyst layer 1-1 (the denitration catalyst layer 1-1 is filled with a denitration catalyst, specifically a (vanadium-based catalyst). NOx in the flue gas is mixed with the injected ammonia (NH3), and a chemical reaction occurs with NH3 under the action of the denitration catalyst to generate N2 and H2O, thereby achieving the purpose of removing NOx in the flue gas. The clean flue gas is drawn by the main exhaust fan 6, enters the coke oven chimney 7 and is discharged into the atmosphere.

[0084] When the flue gas discharged from the flue gas outlet of the flue gas denitrification device (flue gas after denitrification) is > 130mg / m 3 , perform analysis.

[0085] Example 2

[0086] Use Figure 1 The device shown denitrates the denitration catalyst in Example 1, and selects the first flue gas denitration device (first denitration bin) on the left for denitration, while the other six denitration bins perform normal denitration.

[0087] Specifically, the method for recycling flue gas by thermal decomposition of coke oven flue gas denitration catalyst comprises the following steps (process flow chart as follows Figure 3 As shown, Figure 3 This is a thermal analysis process flow chart of the denitration catalyst of Example 2 of the present invention):

[0088] 1) First close the ammonia injection valve corresponding to the first denitrification bin and the fourth valve at the entrance of the corresponding bag dust removal bin, so that the first denitrification bin is offline and in a denitrification stop state. Close the coke oven flue gas outlet valve of the first denitrification bin so that the decomposed flue gas is no longer discharged to the coke oven chimney through the main exhaust fan.

[0089] 2) Open the first valve corresponding to the first denitration tank, close the first valves of other non-analytical denitration tanks, and open the third valve.

[0090] 3) Turn on the booster fan, adjust the second valve and the motor frequency of the booster fan, so that the first denitrification bin and the hot air furnace maintain appropriate pressures. The hot air furnace pressure is guaranteed to be -600~-1000Pa. The pressure of the first denitrification bin is -1500~-2000Pa.

[0091] 4) Turn on the hot blast furnace, which burns coke oven gas to provide high-temperature flue gas for catalyst decomposition. By adjusting the fan frequency, hot flue gas flow rate and temperature, the high-temperature flue gas is kept at 380°C (i.e., the heating decomposition temperature) when it flows through the first denitration bin, so that the dust, ammonium sulfate and other substances on the catalyst surface are decomposed and the catalyst is purified.

[0092] 5) Collecting the analyzed flue gas after the heating analysis to the analyzed flue gas outlet pipe.

[0093] 6) The desulfurized flue gas in the desulfurized flue gas outlet pipe is transported to the coke oven flue gas inlet main pipe through a booster fan for desulfurization.

[0094] 7) The desulfurized flue gas enters the bag dust removal bin for dust removal.

[0095] 8) The flue gas after dust removal enters the non-analytical denitrification chamber in the flue gas denitrification device for denitrification, and the flue gas after denitrification is discharged externally.

[0096] 9) After heating and decomposition for 48 hours, when decomposition is completed, stop the hot air furnace, stop the booster fan, close the first valve, the second valve and the third valve of the first denitrification bin. Open the fourth valve corresponding to the entrance of the bag dust removal bin and the coke oven flue gas outlet valve of the first denitrification bin, open the ammonia injection valve, and restore the working state of coke oven flue gas desulfurization and denitrification.

[0097] The other six denitration chambers were analyzed in turn according to the above method, and the denitration efficiency of the above seven denitration chambers before and after the analysis was completed was calculated. The experimental results show that after the denitration catalyst of the coke oven is analyzed, the denitration efficiency of the coke oven flue gas can be increased from 50% to 60% to 72% to 83%.

[0098] Comparative Example 1

[0099] The denitration catalyst in Example 1 is degraded by the existing method, and the first flue gas denitration device on the left (the first denitration bin) is selected for denitration, and the other six denitration bins are denitrated normally. Specifically, the method for thermal denitration of coke oven flue gas denitration catalyst includes the following steps (process flow as shown in FIG. Figure 4 As shown, Figure 4 The thermal analysis process flow chart of the denitration catalyst of Comparative Example 1 is as follows:

[0100] 1) First close the ammonia injection valve corresponding to the first denitrification bin and the fourth valve at the entrance of the corresponding bag dust removal bin, so that the first denitrification bin is offline and in a denitrification stop state. The coke oven flue gas outlet valve of the first denitrification bin is closed by 2 / 3.

[0101] 2) Adjust the coke oven flue gas outlet valve of the first denitration bin to ensure that the pressure of the hot blast furnace hall is -600 to -1000 Pa. The pressure of the first denitration bin is -1500 to -2000 Pa.

[0102] 3) Turn on the hot blast furnace, which burns coke oven gas to provide high-temperature flue gas for catalyst decomposition. By adjusting the fan frequency, hot flue gas flow rate and temperature, the high-temperature flue gas is kept at 380°C (i.e., the temperature for heating decomposition) when it flows through the first denitration bin, so that the dust, ammonium sulfate and other substances on the catalyst surface are decomposed and the catalyst is purified.

[0103] 4) The purified flue gas passes through the coke oven flue gas outlet of the first denitrification bin and is sent into the coke oven chimney by the exhaust fan and discharged into the atmosphere.

[0104] The other six denitration chambers were analyzed in turn according to the above method, and the denitration efficiency of the above seven denitration chambers before and after the analysis was completed was calculated. The experimental results show that after the denitration catalyst of the coke oven is analyzed, the denitration efficiency of the coke oven flue gas can be increased from 50% to 60% to 65% to 68%.

[0105] The description of the above embodiments is only used to help understand the method of the present invention and its core idea. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features disclosed herein.

Claims

1. A device for recycling flue gas from coke oven flue gas by thermal desorption of denitrification catalyst, comprising: Flue gas denitrification device; The flue gas denitrification device is equipped with an ammonia injection pipeline and a flue gas heating pipeline; The heating flue gas duct is connected to the hot blast furnace; A coke oven flue gas outlet main pipe connected to the coke oven flue gas outlet of the flue gas denitration device; A deionized flue gas outlet pipe connected to the deionized flue gas outlet of the flue gas denitrification device; A booster fan connected to the smoke outlet of the analyzed smoke collection duct; The outlet pipe of the booster fan is connected to the coke oven smoke inlet main pipe through a pipe interface; a desulfurizing agent injection port is arranged at the pipe interface of the coke oven smoke inlet main pipe; A bag dust removal bin is connected to the flue gas outlet of the coke oven flue gas inlet main pipe; the flue gas outlet of the bag dust removal bin is connected to the flue gas inlet of the flue gas denitrification device.

2. The device according to claim 1, characterized in that The decomposed flue gas outlet is arranged at the top of the flue gas denitration device; A first valve is arranged on the pipeline between the analytical flue gas outlet pipeline and the flue gas denitration device.

3. The device according to claim 1, characterized in that The booster fan is provided with a second valve.

4. The device according to claim 1, characterized in that A third valve is provided at the pipeline interface of the air outlet pipeline of the booster fan.

5. The device according to claim 1, characterized in that A denitration catalyst layer is arranged in the flue gas denitration device.

6. The device according to claim 1, characterized in that The flue gas denitration device is provided with an ammonia injection port, and the ammonia injection port is connected to the ammonia injection pipeline; an ammonia injection valve is provided on the ammonia injection port.

7. The device according to claim 1, characterized in that A coke oven flue gas outlet valve is arranged at the coke oven flue gas outlet of the flue gas denitration device.

8. The device according to claim 1, characterized in that The device also includes: A main exhaust fan connected to the flue gas outlet of the coke oven flue gas outlet main pipe; and a coke oven chimney connected to the smoke outlet of the main exhaust fan.

9. A method for recycling flue gas from thermal decomposition of a coke oven flue gas denitration catalyst, comprising the following steps: A) selecting a denitration catalyst in a denitration bin of a flue gas denitration device for heating and decomposition; B) collecting the analyzed flue gas after the heating analysis to the analyzed flue gas outlet pipe; C) the desulfurized flue gas in the desulfurized flue gas outlet pipe is transported to the coke oven flue gas inlet main pipe through a booster fan for desulfurization; D) the desulfurized flue gas enters the bag dust removal bin for dust removal; E) The flue gas after dust removal enters the non-analytical denitrification bin in the flue gas denitrification device for denitrification, and the flue gas after denitrification is discharged externally.

10. The method according to claim 9, characterized in that The temperature of the heating analysis is 320-380°C.

Images