Integrated system and method for flue gas waste heat utilization and harmful gas treatment of tilting furnace

Abstract

This disclosure provides an integrated system and method for waste heat utilization and harmful gas treatment of a tilting furnace flue gas. The system includes at least: a tilting furnace, a secondary combustion chamber, a waste heat boiler, a micro heat pipe array heat exchanger unit, a bag filter, a main fan, a Venturi scrubber, an oxidation desulfurization tower, an electrostatic precipitator, a GGH heat exchanger, an SCR denitrification reactor, and a relay fan. The technical solution of this disclosure achieves efficient utilization of high-temperature flue gas from the tilting furnace and, combined with the characteristics of the flue gas and the process, organically and holistically achieves harmful gas treatment. This not only realizes energy conservation, emission reduction, and environmental protection but also reduces the heat load of environmental protection equipment such as dust removal and desulfurization equipment.

Description

Technical Field

[0001] This disclosure relates to the field of waste heat utilization technology for metallurgical furnaces and kilns and atmospheric environmental governance, and more specifically, to an integrated system and method for waste heat utilization and harmful gas treatment of tilting furnace flue gas. Background Technology

[0002] Metallurgical furnaces and kilns release flue gas with high heat and large volume, possessing significant utilization value. Most of this flue gas undergoes heat exchange through boiler equipment to generate steam for power generation, thus generating economic benefits. It is worth noting that energy loss occurs during the conversion of boiler steam thermal energy into mechanical energy, and mechanical energy into electrical energy. Furthermore, there are further losses during the conversion of electrical energy into other forms of energy, resulting in wasted energy.

[0003] Metallurgical furnace flue gas contains soot, sulfur dioxide, nitrogen oxides, dioxins, and other environmentally harmful components. It requires dust removal and harmless treatment before being released into the atmosphere, which places significant demands on flue gas temperature. Dust removal and desulfurization equipment generally requires flue gas temperatures to be reduced to a certain range, and to ensure desulfurization and denitrification efficiency, dust removal and purification treatment must be prioritized. After dust removal and purification, the low-temperature flue gas needs to be further heated to a suitable temperature range for SCR denitrification.

[0004] Prior art 1 (application number: 202411591089.3, application date: 2024.11.08) discloses a flue gas dust removal and denitrification system, a smelting slag treatment flue gas purification system and process. The smelting slag treatment flue gas purification system includes a metallurgical furnace (1), a vertical flue (2), and a waste heat boiler (3). The flue gas outlet of the metallurgical furnace (1) is connected to the bottom flue gas inlet of the vertical flue (2), and the top flue gas outlet of the vertical flue (2) is connected to the flue gas inlet of the waste heat boiler (3). The feature is that it also includes a waste heat recovery device (5) and a water washing device (8). The desulfurization device (9) and the flue gas dust removal and denitrification system as described in any one of claims 1 to 3; the flue gas outlet of the waste heat boiler (3) is connected to the flue gas inlet channel (401), the flue gas outlet channel (402) is connected to the flue gas inlet of the waste heat recovery device (5), and the flue gas is introduced into the water washing device (8) by the fan (7) after heat exchange in the waste heat recovery device (5); the flue gas outlet of the water washing device (8) is connected to the flue gas inlet of the desulfurization device (9), and the flue gas outlet of the desulfurization device (9) is connected to the chimney (10). In this scheme, the NO after flue gas denitrification x Concentration <100mg / Nm 3 The proposed solution suffers from insufficient flue gas denitrification, resulting in a high concentration of nitrogen oxides in the denitrified flue gas.

[0005] Therefore, the following issues have become urgent technical problems to be solved in this field: 1. Insufficient waste heat recovery and low utilization rate in waste heat boilers; 2. High concentration of nitrogen oxides in flue gas after denitrification. Summary of the Invention

[0006] In view of this, this disclosure provides an integrated system and method for waste heat utilization and harmful gas treatment of tilting furnace flue gas, to solve the above-mentioned technical problems: 1. Insufficient waste heat recovery and low utilization rate in waste heat boilers; 2. High concentration of nitrogen oxides in flue gas after denitrification. This disclosure aims to reduce energy loss during the power generation process of high-temperature flue gas by efficiently utilizing the heat in the high-temperature flue gas and organically combining it with the treatment of harmful gases, achieving a synergistic effect greater than the sum of its parts.

[0007] The first aspect of this disclosure provides an integrated system for waste heat utilization and harmful gas treatment of a tilting furnace flue gas, comprising at least: a tilting furnace, a secondary combustion chamber, a waste heat boiler, a micro heat pipe array heat exchanger unit, a bag filter, a main fan, a Venturi scrubber, an oxidation desulfurization tower, an electrostatic precipitator, a GGH heat exchanger, an SCR denitrification reactor, and a relay fan; wherein...

[0008] The micro heat pipe array heat exchanger unit includes at least a first gas-to-gas heat exchanger, a second gas-to-gas heat exchanger, and a third gas-to-gas heat exchanger, which are sequentially connected by pipelines. The hot-side flue gas inlet of the first gas-to-gas heat exchanger is used to introduce the main flue gas from the waste heat boiler, and the cold-side flue gas inlet of the first gas-to-gas heat exchanger is used to introduce the main flue gas heated by the GGH heat exchanger. The hot-side flue gas outlet of the first gas-to-gas heat exchanger is connected to the hot-side flue gas inlet of the second gas-to-gas heat exchanger by pipelines. The hot-side flue gas outlet of the second gas-to-gas heat exchanger is connected to the hot-side flue gas inlet of the third gas-to-gas heat exchanger by pipelines. The micro heat pipe array heat exchanger unit also includes a first gas-to-water heat exchanger, a second gas-to-water heat exchanger, a third gas-to-water heat exchanger, and a fourth gas-to-gas heat exchanger. The first gas-to-water heat exchanger is connected in series with the hot-side flue gas outlet of the first gas-to-gas heat exchanger. In a pipeline connected to the hot-side flue gas inlet of the first gas-water heat exchanger, the hot-side flue gas inlet of the first gas-water heat exchanger is connected to the hot-side flue gas outlet of the first gas-water heat exchanger, and the hot-side flue gas outlet of the first gas-water heat exchanger is connected to the hot-side flue gas inlet of the second gas-water heat exchanger; in a first branch pipeline connected in series with the second gas-water heat exchanger, the cold-side flue gas outlet of the second gas-water heat exchanger is connected to the cold-side flue gas inlet of the second gas-water heat exchanger, and the cold-side flue gas inlet of the second gas-water heat exchanger is used to introduce combustion air; in a second gas-water heat exchanger connected in series with the first gas-water heat exchanger, the hot-side flue gas outlet of the second gas-water heat exchanger is connected to the cold-side flue gas inlet of the first gas-water heat exchanger; the hot-side flue gas inlet of the second gas-water heat exchanger is connected to the cold-side flue gas outlet of the first gas-water heat exchanger; The third gas-water heat exchanger is connected in series with the first gas-water heat exchanger, wherein the hot-side flue gas inlet of the third gas-water heat exchanger is connected to the cold-side flue gas outlet of the first gas-water heat exchanger; the hot-side flue gas outlet of the third gas-water heat exchanger is connected to the cold-side flue gas inlet of the first gas-water heat exchanger; the fourth gas-to-gas heat exchanger and the third gas-to-gas heat exchanger are connected to the second branch pipeline, wherein the cold-side flue gas outlet of the fourth gas-to-gas heat exchanger is connected to the cold-side flue gas inlet of the third gas-to-gas heat exchanger, and the cold-side flue gas outlet of the third gas-to-gas heat exchanger is connected to the hot-side flue gas inlet of the fourth gas-to-gas heat exchanger, and the cold-side flue gas inlet of the fourth gas-to-gas heat exchanger is used to introduce outdoor cold air.

[0009] The GGH heat exchanger is provided with a cold side flue gas inlet, a cold side flue gas outlet, a hot side flue gas inlet, and a hot side flue gas outlet.

[0010] The tilting furnace, the secondary combustion chamber, the waste heat boiler, and the hot-side flue gas inlet of the first gas-to-gas heat exchanger are connected in sequence by pipelines.

[0011] The hot-side flue gas outlet of the third gas-to-gas heat exchanger, the bag filter, the main fan, the venturi dust collector, the desulfurization tower, the electrostatic precipitator, and the cold-side flue gas inlet of the GGH heat exchanger are connected in sequence by pipelines.

[0012] The cold-side flue gas outlet of the GGH heat exchanger is connected to the cold-side flue gas inlet of the first gas-to-gas heat exchanger via a pipeline, and the cold-side flue gas outlet of the first gas-to-gas heat exchanger is connected to the inlet of the SCR denitrification reactor; the outlet of the SCR denitrification reactor is connected to the hot-side flue gas inlet of the GGH heat exchanger via a pipeline, and the hot-side flue gas outlet of the GGH heat exchanger is connected to the chimney pipeline through the relay fan.

[0013] The cold-side flue gas outlet of the second gas-to-gas heat exchanger is connected to the secondary combustion chamber pipeline; the secondary combustion chamber has a combustion channel with a length of 25.5m, and the secondary combustion chamber is provided with denitrification reaction sites, which include a primary denitrification reaction site, a secondary denitrification reaction site, a tertiary denitrification reaction site, and a quaternary denitrification reaction site arranged sequentially along the airflow direction of the tilting furnace flue gas; the pipeline connecting the secondary combustion chamber and the waste heat boiler is also provided with an SNCR pipeline denitrification reaction site; the pipeline connecting the SNCR pipeline denitrification reaction site and the waste heat boiler is also provided with a nitrogen oxide concentration detection device, used to measure the instantaneous concentration of nitrogen oxides in the secondary denitrification flue gas entering the waste heat boiler inlet; the pipeline connecting the SNCR pipeline denitrification reaction site and the waste heat boiler is also provided with a temperature detection device, used to measure the temperature of nitrogen oxides in the secondary denitrification flue gas entering the waste heat boiler inlet.

[0014] Optionally, ammonia injection devices are provided at the primary denitrification reaction sites, the secondary denitrification reaction sites, the tertiary denitrification reaction sites, the quaternary denitrification reaction sites, and the SNCR pipeline denitrification reaction sites, and the ammonia injection devices are equipped with switch valves.

[0015] Optionally, the bag filter dust collector is equipped with a powdered activated carbon injection point.

[0016] A second aspect of this disclosure provides a method for utilizing waste heat from a tilting furnace flue gas and treating harmful gases. The method employs the aforementioned integrated system for utilizing waste heat from a tilting furnace flue gas and treating harmful gases. The method includes:

[0017] The flue gas from the tilting furnace is introduced into the secondary combustion chamber for SNCR denitrification I. Along the airflow direction of the flue gas, the flue gas exiting the tilting furnace sequentially passes through the primary denitrification reaction sites, secondary denitrification reaction sites, and tertiary denitrification reaction sites within the secondary combustion chamber, reacting with the ammonia water in the secondary combustion chamber to generate primary denitrified flue gas. The temperature of the flue gas from the tilting furnace is 1100℃-1250℃, and the flue gas flow rate is 15000 Nm³.3 / h-22000 Nm 3 / h; In the secondary combustion chamber, the reaction temperature at the primary denitrification reaction site is 1000℃-1100℃, and the ammonia injection rate is 485L / h-510L / h; the reaction temperature at the secondary denitrification reaction site is 900℃-1000℃, and the ammonia injection rate is 450L / h-490L / h; the reaction temperature at the tertiary denitrification reaction site is 850℃-900℃, and the ammonia injection rate is 390 L / h-450 L / h; in the SNCR denitrification I, the mass concentration of ammonia water in the ammonia injection is 15%-25%;

[0018] The primary denitrification flue gas undergoes SNCR denitrification II at the SNCR pipeline denitrification reaction site to obtain secondary denitrification flue gas. This secondary denitrification flue gas is then fed into the waste heat boiler for heat recovery to obtain the main flue gas for the waste heat boiler. The reaction temperature at the SNCR pipeline denitrification reaction site is 830℃-875℃, and the ammonia injection rate is 390 L / h-410 L / h. In the SNCR denitrification II process, the mass concentration of ammonia water in the injected ammonia is 15%-25%.

[0019] The main flue gas from the waste heat boiler is introduced into the micro heat pipe array heat exchanger unit, where it exchanges heat with the heated main flue gas and cooling gas introduced into the GGH heat exchanger unit to obtain the main heat exchange gas. The temperature of the main flue gas from the waste heat boiler is 500℃-600℃, and the flue gas flow rate is 15000 Nm³. 3 / h-22000Nm 3 / h; the temperature of the main heat exchange gas is not higher than 200℃; the cooling gas includes at least the combustion air and the outdoor cold air; wherein, the combustion air is introduced into the micro heat pipe array heat exchanger unit through the cold side flue gas inlet of the second gas-to-gas heat exchanger for heat exchange, and the heat-exchanged combustion air is introduced into the second combustion chamber; the outdoor cold air is heat-exchanged sequentially through the fourth gas-to-gas heat exchanger and the third gas-to-gas heat exchanger.

[0020] The main heat exchange gas is introduced into the bag filter to collect particulate dust in the flue gas, obtaining primary dust-removed flue gas. The activated carbon in the bag filter has a particle size of 200-325 mesh and an injection velocity of 15-25 m / s. The primary dust-removed flue gas sequentially passes through the Venturi scrubber, the desulfurization oxidation tower, and the electrostatic precipitator to obtain secondary dust-removed flue gas, which is then introduced into the GGH heat exchanger to exchange heat with the denitrification flue gas introduced through the hot-side flue gas inlet of the GGH heat exchanger, obtaining the main flue gas after the GGH heat exchanger has been heated. This denitrification flue gas is obtained after denitrification in the SCR denitrification reactor. The denitrification flue gas is discharged from the hot-side flue gas outlet of the GGH heat exchanger after heat exchange. The temperature of the denitrification flue gas is 200℃-450℃, and the flue gas volume is 29000 Nm³. 3 / h -34000Nm 3 / h, the temperature of the flue gas at the hot side outlet of the GGH heat exchanger is 85℃-120℃; the temperature of the flue gas from the secondary dust removal process is 20℃-65℃, and the flue gas volume is 29000Nm³. 3 / h-32000Nm 3 / h, the temperature of the main flue gas after heating by the GGH heat exchanger is 185℃-390℃; the flue gas volume in the SCR denitrification reactor is 30000 Nm³. 3 / h-32000Nm 3 The reaction rate is 300℃-350℃ per hour; the nitrogen oxide content at the outlet is no more than 50 mg / Nm³. 3 ;

[0021] After the GGH heat exchanger is heated, the main flue gas enters through the cold side flue gas inlet of the first gas-to-gas heat exchanger in the micro heat pipe array heat exchanger unit. After heat exchange, the heated main flue gas from the GGH heat exchanger is introduced into the SCR denitrification reactor for SCR denitrification to obtain the denitrified flue gas.

[0022] Optionally, the temperature of the flue gas from the tilting furnace is independently selected from any value among 1100℃, 1150℃, 1200℃, and 1250℃, or any range between any two of the above points.

[0023] Optionally, the flue gas volume of the tilting furnace is independently selected from 15000 Nm³. 3 / h, 17000 Nm 3 / h, 19000Nm 3 / h、21000 Nm 3 / h、22000 Nm 3 Any value in / h or any range of values ​​between any two points mentioned above.

[0024] Optionally, the reaction temperature at the primary denitrification reaction site is independently selected from any value among 1000℃, 1050℃, and 1100℃, or any range between any two of the above points.

[0025] Optionally, the ammonia injection rate at the primary denitrification reaction site is independently selected from any value among 485 L / h, 490 L / h, 495 L / h, 500 L / h, and 510 L / h, or any range between any two of the above points.

[0026] Optionally, the reaction temperature at the secondary denitrification reaction site is independently selected from any value among 900℃, 920℃, 940℃, 960℃, 985℃, and 1000℃, or any range between any two of the above points.

[0027] Optionally, the ammonia injection rate at the secondary denitrification reaction site is independently selected from any value among 450 L / h, 470 L / h, 485 L / h, and 490 L / h, or any range between any two of the above points.

[0028] Optionally, the reaction temperature at the three-stage denitrification reaction site is independently selected from any value among 850℃, 865℃, 880℃, and 900℃, or any range between any two of the above points.

[0029] Optionally, the ammonia injection rate at the three-stage denitrification reaction site is independently selected from any value among 390 L / h, 410 L / h, 430 L / h, 445 L / h, and 450 L / h, or any range between any two of the above points.

[0030] Optionally, in the SNCR denitrification I, the mass concentration of ammonia water in the ammonia injection is independently selected from any value among 15%, 20%, and 25%, or any range between any two of the above points.

[0031] Optionally, the reaction temperature at the denitrification reaction site of the SNCR pipeline is independently selected from any value among 830℃, 835℃, 850℃, and 875℃, or any range between any two of the above points.

[0032] Optionally, the ammonia injection rate at the denitrification reaction site of the SNCR pipeline is independently selected from any value among 390L / h, 400L / h, 405L / h, and 410L / h, or any range between any two of the above points.

[0033] Optionally, in the SNCR denitrification II process, the mass concentration of ammonia water in the ammonia injection is independently selected from any value among 15%, 20%, and 25%, or any range between any two of the above points.

[0034] Optionally, the temperature of the main flue gas from the waste heat boiler is independently selected from any value among 500℃, 525℃, 550℃, 575℃, and 600℃, or any range between any two of the above points.

[0035] Optionally, the flue gas volume of the main flue gas from the waste heat boiler is independently selected from 15000 Nm³. 3 / h, 16500Nm 3 / h, 16830Nm 3 / h, 18000Nm 3 / h, 20000Nm 3 / h, 22000Nm 3 Any value in / h or any range of values ​​between any two points mentioned above.

[0036] Optionally, the method further includes:

[0037] The combustion-supporting air is annular flue gas;

[0038] The temperature of the annular flue gas is 30℃-65℃; the flue gas volume is 500 Nm³. 3 / h -4000Nm 3 / h;

[0039] The temperature of the combustion air after heat exchange is 90℃-400℃.

[0040] Optionally, the method further includes:

[0041] When the instantaneous concentration of nitrogen oxides in the secondary denitrification flue gas exceeds 250 mg / Nm³ 3 When the fourth-stage denitrification reaction site is activated; when the instantaneous concentration of nitrogen oxides in the second-stage denitrification flue gas is below 150 mg / Nm³. 3 Alternatively, if the temperature of the secondary denitrification flue gas is below 830°C, then ammonia injection will cease at the primary denitrification reaction site, the secondary denitrification reaction site, the tertiary denitrification reaction site, and the SNCR pipeline denitrification reaction site.

[0042] Optionally, the method further includes:

[0043] The reaction temperature at the four-stage denitrification reaction sites is 830℃-875℃, and the ammonia injection rate is 390 L / h-430 L / h.

[0044] Optionally, the reaction temperature at the four-stage denitrification reaction site is independently selected from any value among 830℃, 835℃, 850℃, 865℃, and 875℃, or any range between any two of the above points.

[0045] Optionally, the ammonia injection rate at the fourth-stage denitrification reaction site is independently selected from any value among 390 L / h, 405 L / h, 415 L / h, and 430 L / h, or any range between any two of the above points.

[0046] Optionally, the method further includes:

[0047] The cooling gas also includes oxidizing mixed air and cooling protective gas;

[0048] The oxidizing mixed air and the cooling protection air respectively enter the third gas-water heat exchanger for heat exchange and preheating, to obtain oxidizing mixed air preheated gas or cooling protection air preheated gas, which is then introduced into the tilting furnace.

[0049] Compared with existing technologies, the integrated system and method for waste heat utilization and harmful gas treatment of tilting furnace flue gas provided in this disclosure achieves at least the following beneficial effects:

[0050] First, in the integrated system provided in this disclosure, a secondary combustion chamber is added between the tilting furnace and the SCR denitrification reactor for supplementary combustion, which allows the organic matter that is not fully burned in the tilting furnace to be burned again, reducing the risk of deflagration in the subsequent flue and equipment while avoiding the formation of dioxins; multiple SNCR denitrification reaction sites are set in the secondary combustion chamber, which can be used for denitrification in stages, reducing the denitrification burden in the subsequent SCR denitrification reactor.

[0051] Second, in the integrated system provided in this disclosure, a micro heat pipe array heat exchanger unit is added to the outlet of the waste heat boiler. The micro heat pipe array heat exchanger unit is composed of multiple heat exchanger modules with different functions, which can realize rapid cooling heat exchange and realize multi-stage utilization of flue gas heat. At the same time, after the flue gas passes through the micro heat pipe array heat exchanger unit, it can skip the dioxin synthesis temperature zone to avoid the formation of dioxins.

[0052] Third, in the integrated system provided in this disclosure, the secondary combustion chamber has a 25.5m combustion channel, which can ensure that the combustible organic matter escaping from inside and outside the tilting furnace is fully combusted, prevent dioxins from being synthesized at high temperatures and avoid flash explosions in the flue.

[0053] Fourth, in the method provided in this disclosure, the heat of the high-temperature flue gas is not entirely used to generate steam for power generation. Instead, in combination with the characteristics of the flue gas and the process, the heat is exchanged through the micro heat pipe array heat exchanger unit to heat the purified medium- and high-temperature flue gas for SCR denitrification, thereby achieving ultra-low emissions of nitrogen oxides. In addition, after the cooling gas is heat exchanged through the micro heat pipe array heat exchanger unit, the degree of heat loss in the tilting furnace and secondary combustion chamber caused by low temperature can be reduced.

[0054] Fifth, the method provided in this disclosure can reduce equipment and pipeline corrosion caused by ammonia escape. The multi-stage SNCR denitrification reaction carried out in the secondary combustion chamber and its connection flue to the waste heat boiler can reduce the burden of subsequent SCR denitrification and reduce the concentration of nitrogen oxides in the flue gas after denitrification.

[0055] Sixth, in the method provided in this disclosure, the instantaneous concentration of nitrogen oxides in the flue gas before the waste heat boiler inlet (instantaneous concentration less than 150 mg / Nm³) is measured. 3 The ammonia injection device can be controlled by detecting the temperature (below 830℃) to achieve insufficient ammonia injection in the SNCR denitrification reaction, which can reduce the burden on the later SCR denitrification and reduce the concentration of nitrogen oxides in the flue gas after denitrification.

[0056] Seventh, in the method provided in this disclosure, the flue gas is used instead of the atmosphere. Because the temperature is higher than that of the atmosphere, after heat exchange with the micro heat pipe array heat exchanger unit, the drop in flue gas temperature in the secondary combustion chamber caused by the low temperature of the combustion air gas can be greatly reduced.

[0057] Eighth, in the method provided in this disclosure, the main flue gas of the waste heat boiler can achieve rapid cooling and heat exchange in a very short time (2s-4s) through the micro heat pipe array heat exchanger unit, which can effectively avoid the resynthesis of dioxins.

[0058] Of course, any product implementing this disclosure does not necessarily need to achieve all of the technical effects described above at the same time.

[0059] Other features and advantages of the invention will become clear from the following detailed description of exemplary embodiments of the invention with reference to the accompanying drawings. Attached Figure Description

[0060] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of the invention and, together with their description, serve to explain the principles of the invention.

[0061] Figure 1 This is a schematic diagram of an integrated system for waste heat utilization and harmful gas treatment of a tilting furnace flue gas, and the flow path of the gas medium within the system, provided by an embodiment of this disclosure.

[0062] Figure 2 This is a schematic diagram of a micro heat pipe array heat exchanger unit in an integrated system for waste heat utilization and harmful gas treatment of a tilting furnace flue gas, provided by an embodiment of this disclosure, and the heat transfer path of the gas medium within the micro heat pipe array heat exchanger unit.

[0063] Figure 3 This is a flowchart of a method for utilizing waste heat from flue gas in a tilting furnace and treating harmful gases, provided in an embodiment of this disclosure.

[0064] Among them, 101, tilting furnace; 102, secondary combustion chamber; 103, waste heat boiler; 104, micro heat pipe array heat exchanger unit; 1041, first gas-to-gas heat exchanger; 1042, second gas-to-gas heat exchanger; 1043, third gas-to-gas heat exchanger; 1044, fourth gas-to-gas heat exchanger; 1045, first gas-to-water heat exchanger; 1046, second gas-to-water heat exchanger; 1047, third gas-to-water heat exchanger; 105, bag filter; 106, venturi dust collector; 107, desulfurization tower; 108, electrostatic precipitator; 109, GGH heat exchanger; 110, SCR denitrification reactor; 111, cyclone dust collector; 112, secondary combustion fan; 113, main fan; 114, bypass fan; 115, hot air furnace; 116, relay fan. Detailed Implementation

[0065] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention.

[0066] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use.

[0067] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0068] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0069] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0070] In existing technologies, the treatment of harmful gases mainly involves cascaded step-by-step processing. For example, after dust removal and desulfurization, fuel is burned and heated to a suitable temperature for SCR (Selective Catalytic Reduction) for denitrification. This wastes fuel, and the denitrification effect is unsatisfactory, resulting in high nitrogen oxide concentrations in the flue gas after denitrification. Furthermore, there is some energy loss and waste when the high-temperature flue gas is used for power generation, and the waste heat recovery in waste heat boilers is insufficient and the utilization rate is low.

[0071] To address the aforementioned technical issues, reduce energy loss during the power generation process of high-temperature flue gas, achieve efficient waste heat utilization of tilting furnace flue gas, and efficiently remove harmful gases, this disclosure provides an integrated system and method for waste heat utilization and harmful gas treatment of tilting furnace flue gas. This system efficiently utilizes the heat in high-temperature flue gas and organically combines it with the treatment of harmful gases, achieving a synergistic effect greater than the sum of its parts.

[0072] Example 1

[0073] Reference Figures 1-2 , Figure 1 This is a schematic diagram of an integrated system for waste heat utilization and harmful gas treatment of a tilting furnace flue gas, and the flow path of the gas medium within the system, provided by an embodiment of this disclosure. Figure 2 This is a schematic diagram of a micro heat pipe array heat exchanger unit in an integrated system for waste heat utilization and harmful gas treatment of a tilting furnace flue gas, provided by an embodiment of this disclosure, and the heat transfer path of the gas medium within the micro heat pipe array heat exchanger unit.

[0074] like Figures 1-2 As shown in the figure, the integrated system for waste heat utilization and harmful gas treatment of a tilting furnace flue gas provided in this embodiment includes at least: a tilting furnace 101, a secondary combustion chamber 102, a waste heat boiler 103, a micro heat pipe array heat exchanger unit 104, a bag filter 105, a main fan 113, a Venturi scrubber 106, an oxidation desulfurization tower 107, an electrostatic precipitator 108, a GGH heat exchanger (flue gas heat exchanger) 109, an SCR (selective catalytic reduction) denitrification reactor 110, and a relay fan 116; wherein,

[0075] The micro heat pipe array heat exchanger unit 104 includes at least a first gas-to-gas heat exchanger 1041, a second gas-to-gas heat exchanger 1042, and a third gas-to-gas heat exchanger 1043, which are connected sequentially via pipelines. The hot-side flue gas inlet of the first gas-to-gas heat exchanger 1041 is used to introduce the main flue gas from the waste heat boiler, and the cold-side flue gas inlet of the first gas-to-gas heat exchanger 1041 is used to introduce the main flue gas after it has been heated by the GGH heat exchanger. The hot-side flue gas outlet of 1041 is connected to the hot-side flue gas inlet of the second gas-to-gas heat exchanger 1042 via a pipeline; the cold-side flue gas inlet of the second gas-to-gas heat exchanger 1042 is used to introduce combustion air, and the hot-side flue gas outlet of the second gas-to-gas heat exchanger 1042 is connected to the hot-side flue gas inlet of the third gas-to-gas heat exchanger 1043 via a pipeline; the micro heat pipe array heat exchanger unit 104 also includes a first gas-to-water heat exchanger 1045, a second gas-to-water heat exchanger 1046, a third gas-to-water heat exchanger 1047, and a fourth gas-to-gas heat exchanger 1044;

[0076] The first gas-water heat exchanger 1045 is connected in series in the pipeline connecting the hot-side flue gas outlet of the first gas-gas heat exchanger 1041 and the hot-side flue gas inlet of the second gas-gas heat exchanger 1042. The hot-side flue gas inlet of the first gas-water heat exchanger 1045 is connected to the hot-side flue gas outlet of the first gas-gas heat exchanger 1041, and the hot-side flue gas outlet of the first gas-water heat exchanger 1045 is connected to the hot-side flue gas inlet of the second gas-gas heat exchanger 1042.

[0077] The second gas-water heat exchanger 1046 and the second gas-gas heat exchanger 1042 are connected in series on the first branch pipeline. The cold-side flue gas outlet of the second gas-water heat exchanger 1046 is connected to the cold-side flue gas inlet of the second gas-gas heat exchanger 1042. The cold-side flue gas inlet of the second gas-water heat exchanger 1046 is used to introduce combustion air.

[0078] The second gas-water heat exchanger 1046 is connected in series with the first gas-water heat exchanger 1045, wherein the hot-side flue gas outlet of the second gas-water heat exchanger 1046 is connected to the cold-side flue gas inlet of the first gas-water heat exchanger 1045; the hot-side flue gas inlet of the second gas-water heat exchanger 1046 is connected to the cold-side flue gas outlet of the first gas-water heat exchanger 1045.

[0079] The third gas-water heat exchanger 1047 is connected in series with the first gas-water heat exchanger 1045. The hot-side flue gas inlet of the third gas-water heat exchanger 1047 is connected to the cold-side flue gas outlet of the first gas-water heat exchanger 1045. The hot-side flue gas outlet of the third gas-water heat exchanger 1047 is connected to the cold-side flue gas inlet of the first gas-water heat exchanger 1045.

[0080] The fourth gas-to-gas heat exchanger and the third gas-to-gas heat exchanger are connected to the second branch pipeline. The cold-side flue gas outlet of the fourth gas-to-gas heat exchanger 1044 is connected to the cold-side flue gas inlet of the third gas-to-gas heat exchanger 1043, and the cold-side flue gas outlet of the third gas-to-gas heat exchanger 1043 is connected to the hot-side flue gas inlet of the fourth gas-to-gas heat exchanger 1044. The cold-side flue gas inlet of the fourth gas-to-gas heat exchanger 1044 is used to introduce outdoor cold air.

[0081] The GGH heat exchanger 109 is provided with a cold side flue gas inlet, a cold side flue gas outlet, a hot side flue gas inlet, and a hot side flue gas outlet.

[0082] The hot-side flue gas inlets of the tilting furnace 101, the secondary combustion chamber 102, the waste heat boiler 103, and the first gas-to-gas heat exchanger 1041 are connected in sequence by pipelines.

[0083] The hot-side flue gas outlet of the third gas-gas heat exchanger 1043, the bag filter 105, the main fan 113, the venturi dust collector 106, the desulfurization tower 107, the electrostatic precipitator 108, and the cold-side flue gas inlet of the GGH heat exchanger are connected in sequence by pipelines.

[0084] The cold-side flue gas outlet of the GGH heat exchanger is connected to the cold-side flue gas inlet of the first gas-to-gas heat exchanger 1041 via a pipeline. The cold-side flue gas outlet of the first gas-to-gas heat exchanger 1041 is connected to the inlet of the SCR denitrification reactor 110. The outlet of the SCR denitrification reactor 110 is connected to the hot-side flue gas inlet of the GGH heat exchanger via a pipeline. The hot-side flue gas outlet of the GGH heat exchanger is connected to the chimney pipeline via a relay fan 116.

[0085] The cold-side flue gas outlet of the second gas-to-gas heat exchanger 1042 is connected to the secondary combustion chamber 102 via a pipeline. The secondary combustion chamber 102 has a combustion channel with a length of 25.5m. The secondary combustion chamber 102 is equipped with denitrification reaction sites, which include a primary denitrification reaction site, a secondary denitrification reaction site, a tertiary denitrification reaction site, and a quaternary denitrification reaction site (not shown in the figure) arranged sequentially along the airflow direction of the tilting furnace flue gas. The pipeline connecting the secondary combustion chamber 102 to the waste heat boiler 103 is also equipped with an SNCR (selective non-catalytic reduction) pipeline denitrification reaction site. The pipeline connecting the SNCR pipeline denitrification reaction site to the waste heat boiler 103 is also equipped with a nitrogen oxide concentration detection device (not shown in the figure) to measure the instantaneous concentration of nitrogen oxides in the secondary denitrification flue gas entering the inlet of the waste heat boiler 103. The pipeline connecting the SNCR pipeline denitrification reaction site to the waste heat boiler 103 is also equipped with a temperature detection device (not shown in the figure) to measure the temperature of nitrogen oxides in the secondary denitrification flue gas entering the inlet of the waste heat boiler 103.

[0086] Specifically, this disclosure provides an integrated system for efficient waste heat utilization and harmful gas treatment of a tilting furnace flue gas. The system includes functions of compensated combustion, rapid cooling heat exchange, and flue gas treatment, and can realize multi-stage series and parallel heat exchange, including but not limited to a tilting furnace 101, a secondary combustion chamber 102, a waste heat boiler 103, a micro heat pipe array heat exchanger unit 104, a bag filter 105, a venturi scrubber 106, an oxidation desulfurization tower 107, an electrostatic precipitator 108, a GGH heat exchanger 109, a hot blast stove 115, an SCR denitrification reactor 110, a fan, a chimney, and pipeline valve equipment and accessories.

[0087] In this system, the secondary combustion chamber 102 enables the secondary combustion of unburned organic matter in the tilting furnace, reducing the risk of deflagration in subsequent flues and equipment while preventing dioxin formation. The secondary combustion chamber is a device for secondary combustion of flue gas, and its core functions include destroying unburned harmful substances in the flue gas, improving combustion efficiency, and forcibly separating toxic and harmful components through high temperature (1000℃~1200℃), sufficient residence time (greater than 2 seconds), and thorough turbulent mixing. In this system, the secondary combustion chamber 102 has a 25.5m long combustion channel. This relatively long combustion channel ensures the complete combustion of combustible organic matter escaping from the tilting furnace, preventing dioxin synthesis at high temperatures and avoiding flash explosions in the flue. This system utilizes the secondary combustion chamber to set up multiple stages of different temperature layers and denitrification reaction sites (set by different zone temperatures, with ammonia injection devices installed at the reaction sites) for SNCR denitrification. This allows for multi-stage, under-injection ammonia denitrification while avoiding excessive ammonia escape, achieving maximum removal of nitrogen oxides at the front end and reducing the pressure on the downstream SCR denitrification process.

[0088] Waste heat boiler 103 heats flue gas to generate steam for plant use or for power generation; micro-heat array heat exchanger unit 104 enables multi-stage utilization of flue gas heat and bypasses the dioxin synthesis temperature zone to avoid dioxin formation; bag filter 105 collects particulate dust from the flue gas; Venturi scrubber 106 washes the flue gas from bag filter 105, further reducing particulate matter in the flue gas; main fan 113 is the driver for the directional and rapid flow of flue gas and is located in the pipeline connecting bag filter 105 and Venturi scrubber 106. The upper part includes: an oxidation desulfurization tower 107 to remove sulfur dioxide from flue gas; an electrostatic precipitator 108 to remove acid mist from flue gas; a GGH heat exchanger 109 to exchange heat with flue gas and provide the optimal reaction temperature for flue gas SCR denitrification; a relay fan 116, which is a secondary driver for the directional and rapid flow of flue gas, located on the pipeline of the flue gas outlet on the hot side of the GGH heat exchanger 109, specifically on the pipeline connecting the flue gas outlet on the hot side of the GGH heat exchanger to the chimney; and an SCR denitrification reactor 110 to efficiently remove nitrogen oxides from flue gas.

[0089] A nitrogen oxide concentration detection device is also installed on the pipeline connecting the SNCR denitrification reaction site to the waste heat boiler. This device measures the instantaneous concentration of nitrogen oxides in the secondary denitrification flue gas entering the waste heat boiler inlet. The nitrogen oxide concentration detection device in this disclosure uses a readily available and mature industrial nitrogen oxide concentration detection probe. Specific type, structure, and other parameters are not limited; it only needs to be able to measure the instantaneous concentration of nitrogen oxides in the secondary denitrification flue gas entering the waste heat boiler inlet. When the instantaneous concentration is higher than 250 mg / Nm³... 3 When the concentration exceeds the limit, an alarm is triggered, and the fourth-level denitrification reaction site is activated. This occurs when the instantaneous concentration is below 150 mg / Nm³. 3 When the low standard alarm is completed, ammonia injection at all denitrification reaction sites will stop.

[0090] A temperature detection device is also installed on the pipeline connecting the SNCR denitrification reaction site to the waste heat boiler. This device is used to measure the temperature of nitrogen oxides in the secondary denitrification flue gas entering the waste heat boiler inlet. The specific type of temperature detection device is not further limited in this disclosure. Industrially mature temperature detection thermocouples, sensors, etc. are all acceptable. It is only required that the device can measure the temperature of nitrogen oxides in the secondary denitrification flue gas entering the waste heat boiler inlet. When the temperature is lower than 830°C, a low-level alarm is triggered, and ammonia injection at all denitrification reaction sites is stopped.

[0091] In this disclosure, the micro heat pipe array heat exchanger unit 104 is composed of multiple heat exchanger modules with different functions, wherein the first gas-to-gas heat exchanger 1041, the second gas-to-gas heat exchanger 1042, and the third gas-to-gas heat exchanger 1043 are the main heat exchangers.

[0092] In this disclosure, the heat exchanger 109 uses a heat exchange method in which the medium can be cross-flowed or counter-flowed through the wall tube made of a material with excellent thermal conductivity.

[0093] In this disclosure, in order to reduce equipment and pipeline corrosion caused by ammonia escape, the SNCR denitrification reaction carried out in the secondary combustion chamber 102 and the flue connecting it to the waste heat boiler 103 is a substandard ammonia injection, which can reduce the burden of subsequent SCR denitrification and improve denitrification efficiency.

[0094] In this disclosure, the optimal reaction temperature range for SNCR denitrification is 850℃-1100℃. An SNCR pipeline denitrification reaction site is added in the flue connecting the secondary combustion chamber 102 and the waste heat boiler 103. Combined with the multi-stage denitrification reaction sites in the secondary combustion chamber 102, it is possible to perform denitrification with under-injection ammonia in as many stages as possible, while avoiding excessive ammonia escape, so as to remove as much nitrogen oxide as possible at the front end and reduce the pressure of SCR denitrification at the back end.

[0095] It should be noted that the micro heat pipe array heat exchanger unit 104 in this disclosure adopts the waste heat recovery system for multi-stage utilization of flue gas heat from a tilting furnace in the prior art (application number 202511749530.0, application date 2025.11.26). In this disclosure, only the core structure and process parameters are described. Other specific structures and process parameters refer to the waste heat recovery system and method for multi-stage utilization of flue gas heat from a tilting furnace in the prior art (application number 202511749530.0, application date 2025.11.26).

[0096] In some optional embodiments provided in this disclosure, ammonia injection devices are respectively provided at the primary denitrification reaction sites, secondary denitrification reaction sites, tertiary denitrification reaction sites, quaternary denitrification reaction sites, and SNCR pipeline denitrification reaction sites. Each ammonia injection device is equipped with a switch valve. Ammonia injection can be stopped by removing the ammonia injection device from the corresponding reaction site and closing the valve.

[0097] In some optional embodiments provided in this disclosure, the bag filter 105 is provided with a powdered activated carbon injection point.

[0098] In some optional embodiments provided in this disclosure, the integrated system for waste heat utilization and harmful gas treatment of tilting furnace flue gas provided in this disclosure further includes a cyclone dust collector 111, a secondary combustion air blower 112, a bypass fan 114, and a hot air furnace 115; the cyclone dust collector 111 and the secondary combustion air blower 112 are connected in series on the connecting pipe of the cold side flue gas inlet II, and the combustion air (circulating flue gas) is sequentially introduced into the cold side flue gas inlet of the second gas-to-gas heat exchanger 1042 of the micro heat pipe array heat exchanger unit 104 through the cyclone dust collector 111 and the secondary combustion air blower 112 for preheating; the bypass fan 114 is connected to the pipe connecting the micro heat pipe array heat exchanger unit 104 and the bag dust collector 105, the pipe connecting the main fan 113 and the venturi dust collector 106, and the secondary combustion air blower 112 respectively; the hot air furnace 115 is connected in parallel to the pipe connecting the micro heat pipe array heat exchanger unit 104 and the SCR denitrification reactor 110.

[0099] This disclosed integrated system for waste heat utilization and hazardous gas treatment of tilting furnace flue gas utilizes the high-temperature flue gas from the tilting furnace outlet in multiple stages, constructing an integrated flue gas system for hazardous gas treatment. The system ensures the complete degradation and elimination of dioxins in the flue gas through measures such as flue gas compensation combustion, rapid cooling, and activated carbon adsorption. The system incorporates SNCR denitrification reaction sites at different temperature layers in the secondary combustion chamber at the tilting furnace flue gas outlet. After primary denitrification and flue gas purification, the gas exchanges heat with the high-temperature flue gas from the furnace through a heat exchanger, creating a medium-temperature flue gas environment conducive to SCR denitrification, enabling secondary, highly efficient denitrification and achieving ultra-low nitrogen oxide emissions. This system features efficient waste heat utilization, excellent tail gas treatment efficiency, and is economically and environmentally friendly.

[0100] As can be seen from the above embodiments, the integrated system for waste heat utilization and harmful gas treatment of tilting furnace flue gas provided in this disclosure achieves at least the following beneficial effects:

[0101] This embodiment achieves efficient utilization of high-temperature flue gas from a tilting furnace and, combined with the characteristics of the flue gas and the process, organically and holistically achieves the treatment of harmful gases. It not only realizes energy conservation, emission reduction, and environmental protection, but also reduces the heat load on environmental protection equipment such as dust removal and desulfurization equipment. Furthermore, it can be applied to the smelting industry and other high-temperature flue gas treatment applications. Specific beneficial effects include:

[0102] 1. In the integrated system provided in this embodiment, a secondary combustion chamber is added between the tilting furnace and the SCR denitrification reactor for supplementary combustion. This allows the organic matter that has not been fully combusted in the tilting furnace to be combusted again, reducing the risk of deflagration in the subsequent flue and equipment while avoiding the formation of dioxins. Multiple SNCR denitrification reaction sites are set in the secondary combustion chamber, which can be used for denitrification in stages, reducing the denitrification burden in the subsequent SCR denitrification reactor.

[0103] 2. In the integrated system provided in this embodiment, a micro heat pipe array heat exchanger unit is added to the outlet of the waste heat boiler. The micro heat pipe array heat exchanger unit is composed of multiple heat exchanger modules with different functions, which can realize rapid cooling heat exchange and realize multi-stage utilization of flue gas heat. At the same time, after the flue gas passes through the micro heat pipe array heat exchanger unit, it can skip the dioxin synthesis temperature zone to avoid the formation of dioxins.

[0104] 3. In the integrated system provided in this embodiment, the secondary combustion chamber has a 25.5m combustion channel, which can ensure that the combustible organic matter escaping from the tilting furnace is fully combusted, prevent dioxins from being synthesized at high temperatures and avoid flash explosions in the flue.

[0105] Example 2

[0106] Reference Figures 1-3 , Figure 1 This is a schematic diagram of an integrated system for waste heat utilization and harmful gas treatment of a tilting furnace flue gas, and the flow path of the gas medium within the system, provided by an embodiment of this disclosure. Figure 2 This is a schematic diagram of a micro heat pipe array heat exchanger unit in an integrated system for waste heat utilization and harmful gas treatment of a tilting furnace flue gas, provided by an embodiment of this disclosure, and the heat transfer path of the gas medium within the micro heat pipe array heat exchanger unit. Figure 3 This is a flowchart of a method for utilizing waste heat from flue gas in a tilting furnace and treating harmful gases, provided in an embodiment of this disclosure.

[0107] like Figures 1-3 As shown, this embodiment provides a method for utilizing waste heat from a tilting furnace flue gas and treating harmful gases. The method employs the aforementioned integrated system for utilizing waste heat from a tilting furnace flue gas and treating harmful gases. The flue gas exiting the tilting furnace (i.e., the tilting furnace flue gas) flows through the system's path (e.g.,...) Figure 1 , Figure 2 As shown below:

[0108] The flue gas from the tilting furnace outlet (i.e., the flue gas from the tilting furnace) passes sequentially through the secondary combustion chamber 102, the waste heat boiler 103, the micro heat pipe array heat exchanger unit 104, the bag filter 105, the main fan 113, the venturi dust collector 106, the desulfurization tower 107, the electrostatic precipitator 108, the GGH heat exchanger 109, the micro heat pipe array heat exchanger unit 104, the SCR denitrification reactor 110, the GGH heat exchanger 109, the relay fan 116, and the chimney. The SNCR denitrification reaction site is located in the secondary combustion chamber 102 and the flue connecting it to the waste heat boiler 103. A powdered activated carbon injection point is provided before the flue inlet of the bag filter 105.

[0109] Specific methods are as follows Figure 3 As shown, it includes:

[0110] Step S100: The flue gas from the tilting furnace is introduced into the secondary combustion chamber 102 for SNCR denitrification I. Along the airflow direction of the flue gas from the tilting furnace, the flue gas exiting the tilting furnace sequentially passes through the primary denitrification reaction sites, secondary denitrification reaction sites, and tertiary denitrification reaction sites within the secondary combustion chamber 102, reacting with the ammonia water in the secondary combustion chamber 102 to generate primary denitrified flue gas. The temperature of the flue gas from the tilting furnace is 1100℃-1250℃, and the flue gas flow rate is 15000 Nm³. 3 / h-22000 Nm 3 / h; In the secondary combustion chamber, the reaction temperature at the primary denitrification reaction site is 1000℃-1100℃, and the ammonia injection rate is 485L / h-510L / h; the reaction temperature at the secondary denitrification reaction site is 900℃-1000℃, and the ammonia injection rate is 450L / h-490L / h; the reaction temperature at the tertiary denitrification reaction site is 850℃-900℃, and the ammonia injection rate is 390L / h-450L / h; in SNCR denitrification I, the mass concentration of ammonia water in the ammonia injection is 15%-25%;

[0111] In step S200, the primary denitrification flue gas undergoes SNCR denitrification II at the SNCR pipeline denitrification reaction site to obtain secondary denitrification flue gas. This secondary denitrification flue gas is then fed into the waste heat boiler 103 for heat recovery to obtain the main flue gas for the waste heat boiler. The reaction temperature at the SNCR pipeline denitrification reaction site is 830℃-875℃, and the ammonia injection rate is 390L / h-410L / h. In SNCR denitrification II, the mass concentration of ammonia water in the injected ammonia is 15%-25%.

[0112] Step S300: The main flue gas from the waste heat boiler is introduced into the micro heat pipe array heat exchanger unit 104, where it exchanges heat with the heated main flue gas and cooling gas in the GGH heat exchanger unit 104 to obtain the main heat exchange gas. The temperature of the main flue gas from the waste heat boiler is 500℃-600℃, and the flue gas volume is 15000 Nm³. 3 / h-22000Nm 3 / h; the temperature of the main heat exchanger is not higher than 200℃; the cooling gas includes at least combustion air and outdoor cold air; wherein, the combustion air is introduced into the micro heat pipe array heat exchanger unit 104 through the cold side flue gas inlet of the second gas-to-gas heat exchanger 1042 for heat exchange, and the heat-exchanged combustion air is introduced into the secondary combustion chamber; the outdoor cold air is introduced into the micro heat pipe array heat exchanger unit 104 through the cold side flue gas inlets of the fourth gas-to-gas heat exchanger 1044 and the third gas-to-gas heat exchanger 1043 for heat exchange; the heat-exchanged air can be introduced into the cold material storage area of ​​the workshop for use.

[0113] Step S400: The main heat exchange gas is introduced into the bag filter 105 to collect particulate dust in the flue gas and obtain primary dust-removed flue gas. The activated carbon in the bag filter 105 has a particle size of 200-325 mesh and an injection velocity of 15-25 m / s. The primary dust-removed flue gas passes sequentially through a Venturi dust collector 106, an oxidation desulfurization tower 107, and an electrostatic precipitator 108 to obtain secondary dust-removed flue gas, which is then introduced into the GGH heat exchanger 109 to exchange heat with the denitrification flue gas introduced through the hot-side flue gas inlet of the GGH heat exchanger, obtaining the main flue gas after the GGH heat exchanger has been heated. The denitrification flue gas is obtained after denitrification in the SCR denitrification reactor. After heat exchange, the denitrification flue gas is discharged from the hot-side flue gas outlet of the GGH heat exchanger. The temperature of the denitrification flue gas is 200℃-450℃, and the flue gas volume is 29000 Nm³. 3 / h -34000Nm 3 / h, the flue gas temperature at the hot side outlet of the GGH heat exchanger is 85℃-120℃; the temperature of the flue gas from the secondary dust removal system is 20℃-65℃, and the flue gas volume is 29000Nm³. 3 / h-32000Nm 3 / h, the temperature of the main flue gas after heating by the GGH heat exchanger is 185℃-390℃; the flue gas volume in the SCR denitrification reactor is 30000 Nm³. 3 / h-32000Nm 3 The reaction rate is 300℃-350℃ per hour; the nitrogen oxide content at the outlet is no more than 50 mg / Nm³. 3 ;

[0114] In step S500, after the GGH heat exchanger is heated, the main flue gas enters through the cold side flue gas inlet of the first gas-to-gas heat exchanger 1041 in the micro heat pipe array heat exchanger unit 104. After heat exchange, the heat exchanged gas of the main flue gas after the GGH heat exchanger is heated is introduced into the SCR denitrification reactor 110 for SCR denitrification to obtain denitrified flue gas. The denitrified flue gas is introduced into the GGH heat exchanger and, according to step S400, exchanges heat with the secondary dust removal flue gas.

[0115] In this disclosure, the flue gas temperature of the tilting furnace is 1100℃-1250℃ (above 1150℃, the tilting furnace experiences a large heat load, causing significant damage to the furnace; therefore, the temperature generally does not exceed 1150℃), and the flue gas volume is 15000 Nm³. 3 / h -22000Nm 3 The secondary combustion chamber is equipped with denitrification reaction sites at temperatures of 1000℃-1100℃ (ammonia injection rate of 485 L / h - 510 L / h), 900℃-1000℃ (ammonia injection rate of 450-490 L / h), 850-900℃ (ammonia injection rate of 390-450 L / h), and 830℃-875℃ (spare) (ammonia injection rate of 390-430 L / h). In this disclosure, the primary, secondary, tertiary, and quaternary denitrification reaction sites are arranged along the airflow direction, and their relative positions are obtained from temperature measurements of different flue gas flow areas within the secondary combustion chamber, thus enabling temperature segmentation.

[0116] In this disclosure, the flue connecting the secondary combustion chamber 102 and the waste heat boiler 103 also contains SNCR denitrification reaction sites, and a nitrogen oxide concentration detection point is provided before the inlet of the waste heat boiler 103; when the instantaneous nitrogen oxide concentration in the secondary combustion chamber 102 and its connecting flue to the waste heat boiler 103 is lower than 150 mg / Nm³, 3 If the temperature is below 830℃, ammonia injection will be stopped at all denitrification reaction sites.

[0117] In this disclosure, to reduce equipment and pipeline corrosion caused by ammonia escape, the SNCR denitrification reaction in the secondary combustion chamber 102 and its connection flue to the waste heat boiler 103 involves under-injection of ammonia. This reduces the burden on subsequent SCR denitrification and improves denitrification efficiency. Careful control of the ammonia injection time is crucial; the ammonia injection should be timed precisely when the instantaneous NO at the SNCR reaction site... x Concentration below 150 mg / Nm 3 If so, ammonia injection will stop, resulting in under-injection of ammonia.

[0118] In this disclosure, the main flue gas from the waste heat boiler flows through a micro heat pipe array heat exchanger unit 104, where it exchanges heat with purified high-temperature flue gas (the main flue gas heated by the GGH heat exchanger) and cooling gases (combustion air, oxidation mixed air, cooling protective gas, and outdoor cold air). This process can reduce the flue gas temperature from 500℃-600℃ to below 200℃ within 2-4 seconds, with a flue gas volume of 15000 Nm³. 3 / h -22000 Nm 3 / h. The main flue gas can achieve rapid cooling and heat exchange in a very short time after passing through the micro heat pipe array heat exchanger unit 104, which can effectively avoid the resynthesis of dioxins.

[0119] In some optional embodiments provided in this disclosure, the combustion air is annular flue gas;

[0120] The temperature of the flue gas collected in the annular collection is 30℃-65℃; the flue gas volume is 500 Nm³. 3 / h -4000 Nm 3 / h; the temperature of the combustion air after heat exchange is 90℃-400℃.

[0121] It should be noted that, in this disclosure, the annular flue gas refers to the gas that is collected secondary to the atmosphere from the flue gas escaping from the tilting furnace. After passing through the micro heat pipe array heat exchanger unit (specifically the second gas-to-gas heat exchanger), the annular flue gas is heated from 30℃-65℃ to 90℃-400℃ and then enters the secondary combustion chamber as combustion air. The flue gas volume is 500 Nm³. 3 / h-4000 Nm 3 / h, which can replace outdoor air as the combustion air for the secondary combustion chamber. Using annular flue gas instead of atmospheric air, due to its higher temperature, and after heat exchange with the micro heat pipe array heat exchanger, can significantly reduce the temperature drop of the flue gas in the secondary combustion chamber caused by the low temperature of the combustion air. The secondary combustion chamber has a long combustion passage / combustion channel, which can ensure the complete combustion of combustible organic matter escaping from the tilting furnace, prevent dioxin synthesis at high temperatures, and avoid flash explosions in the flue.

[0122] In some optional embodiments provided in this disclosure, the method further includes: when the instantaneous concentration of nitrogen oxides in the secondary denitrification flue gas exceeds 250 mg / Nm³. 3 When the nitrogen oxide concentration in the flue gas from the secondary denitrification stage is below 150 mg / Nm³, the fourth-stage denitrification reaction site is activated; when the instantaneous concentration of nitrogen oxides in the flue gas from the secondary denitrification stage is below 150 mg / Nm³, the fourth-stage denitrification reaction site is activated. 3 Alternatively, if the temperature of the secondary denitrification flue gas is below 830℃, then ammonia injection will stop at the primary denitrification reaction site, the secondary denitrification reaction site, the tertiary denitrification reaction site, and the SNCR pipeline denitrification reaction site. In other words, ammonia injection will stop at all the aforementioned denitrification reaction sites.

[0123] In this disclosure, the outlet temperature of the second combustion chamber is in the range of 830℃-875℃; NO is installed on the flue connecting the SNCR pipeline denitrification reaction point and the waste heat boiler. x Real-time monitoring data shows that when the instantaneous concentration of nitrogen oxides in the secondary denitrification flue gas exceeds 250 mg / Nm³, 3 When the concentration is below 250 mg / Nm³, the backup reaction site (level IV denitrification reaction site) will be activated. 3 The backup reaction site is not used. When not in use, the ammonia injection gun (equipped with a switch valve) is removed from the reaction site.

[0124] In some optional embodiments provided in this disclosure, the method further includes: the reaction temperature at the fourth-stage denitrification reaction site is 830℃-875℃, and the ammonia injection rate is 390 L / h-430 L / h.

[0125] In some optional embodiments provided in this disclosure, the method further includes: the cooling gas further includes oxidizing hybrid air and cooling protective gas;

[0126] Oxidation miscellaneous air and cooling protection air respectively enter the third gas-water heat exchanger 1047 for heat exchange and preheating to obtain oxidation miscellaneous air preheated gas or cooling protection air preheated gas, which is then introduced into the tilting furnace 101 and used specifically as the tilting furnace oxidation miscellaneous air and the tilting furnace cooling protection air.

[0127] In this disclosure, the heat from the high-temperature flue gas is not entirely used to generate steam for power generation. Instead, taking into account the characteristics of the flue gas and the process, the purified medium-to-high-temperature flue gas is heated by heat exchange through a micro heat pipe array heat exchanger for SCR denitrification, achieving ultra-low nitrogen oxide emissions. Furthermore, the cooling gas, after passing through the micro heat pipe array heat exchanger, reduces the degree of heat loss in the furnace and secondary combustion chamber caused by low temperatures.

[0128] This disclosure enables both the utilization of flue gas heat and the treatment of harmful gases. The high-temperature flue gas heat from the tilting furnace outlet is utilized in multiple ways: for example, excess heat is used for bag purging, secondary combustion air in the secondary combustion chamber, and soot blowing in the quench heat exchange system (micro heat pipe array heat exchanger unit). Furthermore, the quench heat exchange system (micro heat pipe array heat exchanger unit) also includes gas-water heat exchanger modules (first gas-water heat exchanger, second gas-water heat exchanger, and third gas-water heat exchanger) and a fourth gas-gas heat exchanger, primarily serving to preheat the low-temperature flue gas and prevent it from directly entering the quench heat exchange system, thus avoiding low-temperature corrosion of the gas-gas heat exchanger modules (including the first gas-gas heat exchanger, second gas-gas heat exchanger, and third gas-gas heat exchanger). Simultaneously, the secondary combustion chamber promotes the complete combustion of unburned organic matter in the tilting furnace, preventing dioxin formation. The quenching heat exchange system (micro heat pipe array heat exchanger unit) rapidly (2s-4s) lowers the flue gas temperature to below 200℃, allowing the flue gas to quickly bypass the dioxin synthesis temperature range (250-450℃). Furthermore, the flue contains activated carbon adsorption and baghouse dust collection to prevent dioxin diffusion and capture dioxins. The quenching heat exchange system (micro heat pipe array heat exchanger unit) also provides heat to the gas-water heat exchanger module and the fourth gas-gas heat exchanger, preheating the external medium before it enters the quenching heat exchange system. Additionally, after heat exchange through the quenching heat exchange system (micro heat pipe array heat exchanger unit) at the cold side flue gas outlet of the GGH, the flue gas after dust removal (desulfurization, dioxin removal) can reach the optimal temperature for SCR denitrification reaction without additional fuel. Unlike conventional methods that use flue gas heat for power generation, this approach achieves an organic combination of heat utilization and harmful gas treatment.

[0129] As can be seen from the above embodiments, the integrated method for waste heat utilization and harmful gas treatment of tilting furnace flue gas provided in this disclosure achieves at least the following beneficial effects:

[0130] 1. In the method provided in this embodiment, the heat of the high-temperature flue gas is not entirely used to generate steam for power generation. Instead, combined with the characteristics of the flue gas and the process, the heat is exchanged through the micro heat pipe array heat exchanger unit to heat the purified medium-high temperature flue gas for SCR denitrification, thereby achieving ultra-low emissions of nitrogen oxides. In addition, after the cooling gas is heat exchanged through the micro heat pipe array heat exchanger unit, the degree of heat loss in the tilting furnace and secondary combustion chamber caused by low temperature can be reduced.

[0131] 2. The method provided in this embodiment can reduce equipment and pipeline corrosion caused by ammonia escape. The multi-stage SNCR denitrification reaction carried out in the secondary combustion chamber and its connection flue to the waste heat boiler can reduce the burden of subsequent SCR denitrification and reduce the concentration of nitrogen oxides in the flue gas after denitrification.

[0132] 3. In the method provided in this embodiment, the instantaneous concentration of nitrogen oxides in the flue gas before the waste heat boiler inlet (instantaneous concentration less than 150 mg / Nm³) is measured. 3 The ammonia injection device can be controlled by detecting the temperature (below 830℃) to achieve insufficient ammonia injection in the SNCR denitrification reaction, which can reduce the burden on the later SCR denitrification and reduce the concentration of nitrogen oxides in the flue gas after denitrification.

[0133] 4. In the method provided in this embodiment, the flue gas is used instead of the atmosphere. Because the temperature is higher than that of the atmosphere, after heat exchange with the micro heat pipe array heat exchanger unit, the drop in flue gas temperature in the secondary combustion chamber caused by the low temperature of the combustion air gas can be greatly reduced. The secondary combustion chamber has a long combustion channel, which can ensure that the combustible organic matter escaping from the tilting furnace is fully burned, prevent dioxins from being synthesized at high temperatures and avoid flash explosions in the flue.

[0134] 5. In the method provided in this embodiment, the main flue gas of the waste heat boiler can achieve rapid cooling and heat exchange in a very short time (2s-4s) through the micro heat pipe array heat exchanger unit, which can effectively avoid the resynthesis of dioxins.

[0135] Example 3

[0136] This embodiment describes the specific implementation process of the above-mentioned integrated system and method for waste heat utilization and harmful gas treatment of tilting furnace flue gas at the Guixi Smelter of Jiangxi Copper Corporation. The parameters of the main flue gas and the surrounding flue gas during the period of maximum flue gas volume are shown in Table 1. After implementation using the system and method disclosed herein, the main parameters of the tilting furnace flue gas along the flue gas flow path are shown in Table 2, where TSP represents total suspended particulate matter; NO... X It is a nitrogen oxide.

[0137] Table 1

[0138]

[0139] Table 2

[0140]

[0141] The GGH heat exchanger has a heat exchange capacity of 2500KW, a hot-side flue gas inlet / outlet temperature of 320℃ / 90℃, and a flue gas volume of 31600Nm³. 3 / h; Cold side flue gas inlet and outlet temperatures 35℃ / 270℃, flue gas volume 31000 Nm³ / h 3 / h.

[0142] The flue gas volume at the primary denitrification reaction site, secondary denitrification reaction site, tertiary denitrification reaction site, and SNCR pipeline denitrification reaction site are 16500 Nm³. 3 / h, 18350Nm 3 / h, 20550Nm 3 / h, 21150Nm 3 / h; reaction temperatures were 1050℃, 985℃, 865℃, and 835℃; ammonia injection rates were 495L / h, 485L / h, 445L / h, and 405L / h; and ammonia water mass was 20% for all reactions.

[0143] Inside the bag filter dust collector, the activated carbon has a particle size of 275 mesh and an injection speed of 18 m / s;

[0144] The flue gas volume of the SCR denitrification reactor is 31500 Nm³. 3 / h, reaction temperature 320℃, outlet NO X ≤50 mg / Nm 3 .

[0145] The temperature of the flue gas after heat exchange through the micro heat pipe array heat exchanger unit is 350℃.

[0146] During the implementation of this embodiment, when the instantaneous concentration of nitrogen oxides in the secondary denitrification flue gas exceeds 250 mg / Nm³, 3 At that time, the fourth-stage denitrification reaction site is activated, the reaction temperature at the fourth-stage denitrification reaction site is 835℃, and the ammonia injection rate is 405L / h.

[0147] The tilting furnace generates 89.9 tons of steam in a single operating cycle (22 hours). The dust removal rate is as high as 99.98%, and the TSP in the exhaust gas is ≤0.01 mg / Nm³. 3 NO X ≤30mg / Nm 3 SO2 ≤ 10 mg / Nm 3 .

[0148] This embodiment achieves efficient utilization of high-temperature flue gas from a tilting furnace, and organically integrates the characteristics of the flue gas and the process to achieve the treatment of harmful gases. It not only achieves energy conservation, emission reduction and environmental protection, but also reduces the heat load of environmental protection equipment such as dust removal and desulfurization. It can also be applied to the smelting industry and other high-temperature flue gas treatment.

[0149] While specific embodiments of the invention have been described in detail by way of examples, those skilled in the art should understand that the examples are for illustrative purposes only and not intended to limit the scope of the invention. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of the invention. The scope of the invention is defined by the appended claims.

Claims

1. An integrated system for waste heat utilization and harmful gas treatment of a tilting furnace flue gas, characterized in that, It includes at least: a tilting furnace, a secondary combustion chamber, a waste heat boiler, a micro heat pipe array heat exchanger unit, a bag filter, a main fan, a Venturi scrubber, an oxidation desulfurization tower, an electrostatic precipitator, a GGH heat exchanger, an SCR denitrification reactor, and a relay fan; among which, The micro heat pipe array heat exchanger unit includes at least a first gas-to-gas heat exchanger, a second gas-to-gas heat exchanger, and a third gas-to-gas heat exchanger, which are sequentially connected by pipelines. The hot-side flue gas inlet of the first gas-to-gas heat exchanger is used to introduce the main flue gas from the waste heat boiler, and the cold-side flue gas inlet of the first gas-to-gas heat exchanger is used to introduce the main flue gas heated by the GGH heat exchanger. The hot-side flue gas outlet of the first gas-to-gas heat exchanger is connected to the hot-side flue gas inlet of the second gas-to-gas heat exchanger by pipelines. The hot-side flue gas outlet of the second gas-to-gas heat exchanger is connected to the hot-side flue gas inlet of the third gas-to-gas heat exchanger by pipelines. The micro heat pipe array heat exchanger unit also includes a first gas-to-water heat exchanger, a second gas-to-water heat exchanger, a third gas-to-water heat exchanger, and a fourth gas-to-gas heat exchanger. The first gas-to-water heat exchanger is connected in series with the hot-side flue gas outlet of the first gas-to-gas heat exchanger. In a pipeline connected to the hot-side flue gas inlet of the first gas-water heat exchanger, the hot-side flue gas inlet of the first gas-water heat exchanger is connected to the hot-side flue gas outlet of the first gas-water heat exchanger, and the hot-side flue gas outlet of the first gas-water heat exchanger is connected to the hot-side flue gas inlet of the second gas-water heat exchanger; in a first branch pipeline connected in series with the second gas-water heat exchanger, the cold-side flue gas outlet of the second gas-water heat exchanger is connected to the cold-side flue gas inlet of the second gas-water heat exchanger, and the cold-side flue gas inlet of the second gas-water heat exchanger is used to introduce combustion air; in a second gas-water heat exchanger connected in series with the first gas-water heat exchanger, the hot-side flue gas outlet of the second gas-water heat exchanger is connected to the cold-side flue gas inlet of the first gas-water heat exchanger; the hot-side flue gas inlet of the second gas-water heat exchanger is connected to the cold-side flue gas outlet of the first gas-water heat exchanger; The third gas-water heat exchanger is connected in series with the first gas-water heat exchanger, wherein the hot-side flue gas inlet of the third gas-water heat exchanger is connected to the cold-side flue gas outlet of the first gas-water heat exchanger; the hot-side flue gas outlet of the third gas-water heat exchanger is connected to the cold-side flue gas inlet of the first gas-water heat exchanger; the fourth gas-to-gas heat exchanger and the third gas-to-gas heat exchanger are connected to the second branch pipeline, wherein the cold-side flue gas outlet of the fourth gas-to-gas heat exchanger is connected to the cold-side flue gas inlet of the third gas-to-gas heat exchanger, and the cold-side flue gas outlet of the third gas-to-gas heat exchanger is connected to the hot-side flue gas inlet of the fourth gas-to-gas heat exchanger, and the cold-side flue gas inlet of the fourth gas-to-gas heat exchanger is used to introduce outdoor cold air. The GGH heat exchanger is provided with a cold side flue gas inlet, a cold side flue gas outlet, a hot side flue gas inlet, and a hot side flue gas outlet. The tilting furnace, the secondary combustion chamber, the waste heat boiler, and the hot-side flue gas inlet of the first gas-to-gas heat exchanger are connected in sequence by pipelines. The hot-side flue gas outlet of the third gas-to-gas heat exchanger, the bag filter, the main fan, the venturi dust collector, the desulfurization tower, the electrostatic precipitator, and the cold-side flue gas inlet of the GGH heat exchanger are connected in sequence by pipelines. The cold-side flue gas outlet of the GGH heat exchanger is connected to the cold-side flue gas inlet of the first gas-to-gas heat exchanger via a pipeline, and the cold-side flue gas outlet of the first gas-to-gas heat exchanger is connected to the inlet of the SCR denitrification reactor; the outlet of the SCR denitrification reactor is connected to the hot-side flue gas inlet of the GGH heat exchanger via a pipeline, and the hot-side flue gas outlet of the GGH heat exchanger is connected to the chimney pipeline through the relay fan. The cold-side flue gas outlet of the second gas-to-gas heat exchanger is connected to the secondary combustion chamber pipeline; the secondary combustion chamber has a combustion channel with a length of 25.5m, and the secondary combustion chamber is provided with denitrification reaction sites, which include a primary denitrification reaction site, a secondary denitrification reaction site, a tertiary denitrification reaction site, and a quaternary denitrification reaction site arranged sequentially along the airflow direction of the tilting furnace flue gas; the pipeline connecting the secondary combustion chamber and the waste heat boiler is also provided with an SNCR pipeline denitrification reaction site; the pipeline connecting the SNCR pipeline denitrification reaction site and the waste heat boiler is also provided with a nitrogen oxide concentration detection device, used to measure the instantaneous concentration of nitrogen oxides in the secondary denitrification flue gas entering the waste heat boiler inlet; the pipeline connecting the SNCR pipeline denitrification reaction site and the waste heat boiler is also provided with a temperature detection device, used to measure the temperature of nitrogen oxides in the secondary denitrification flue gas entering the waste heat boiler inlet.

2. The integrated system for waste heat utilization and harmful gas treatment of tilting furnace flue gas according to claim 1, characterized in that, Ammonia injection devices are provided at the primary denitrification reaction sites, the secondary denitrification reaction sites, the tertiary denitrification reaction sites, the quaternary denitrification reaction sites, and the SNCR pipeline denitrification reaction sites, and the ammonia injection devices are equipped with switch valves.

3. The integrated system for waste heat utilization and harmful gas treatment of tilting furnace flue gas according to claim 1, characterized in that, The baghouse dust collector is equipped with a powdered activated carbon injection point.

4. A method for utilizing waste heat from a tilting furnace flue gas and treating harmful gases, characterized in that, The method employs the integrated system for waste heat utilization and harmful gas treatment of tilting furnace flue gas as described in any one of claims 1 to 3, and the method includes: The flue gas from the tilting furnace is introduced into the secondary combustion chamber for SNCR denitrification I. Along the airflow direction of the flue gas, the flue gas exiting the tilting furnace sequentially passes through the primary denitrification reaction sites, secondary denitrification reaction sites, and tertiary denitrification reaction sites within the secondary combustion chamber, reacting with the ammonia water in the secondary combustion chamber to generate primary denitrified flue gas. The temperature of the flue gas from the tilting furnace is 1100℃-1250℃, and the flue gas flow rate is 15000 Nm³. 3 / h-22000 Nm 3 / h; In the secondary combustion chamber, the reaction temperature at the primary denitrification reaction site is 1000℃-1100℃, and the ammonia injection rate is 485 L / h - 510 L / h; the reaction temperature at the secondary denitrification reaction site is 900℃-1000℃, and the ammonia injection rate is 450 L / h - 490 L / h; the reaction temperature at the tertiary denitrification reaction site is 850℃-900℃, and the ammonia injection rate is 390 L / h - 450 L / h; in the SNCR denitrification I, the mass concentration of ammonia water in the ammonia injection is 15%-25%; The primary denitrification flue gas undergoes SNCR denitrification II at the SNCR pipeline denitrification reaction site to obtain secondary denitrification flue gas. This secondary denitrification flue gas is then fed into the waste heat boiler for heat recovery to obtain the main flue gas for the waste heat boiler. The reaction temperature at the SNCR pipeline denitrification reaction site is 830℃-875℃, and the ammonia injection rate is 390 L / h-410 L / h. In the SNCR denitrification II process, the mass concentration of ammonia in the injected ammonia water is 15%-25%. The main flue gas from the waste heat boiler is introduced into the micro heat pipe array heat exchanger unit, where it exchanges heat with the heated main flue gas and cooling gas introduced into the GGH heat exchanger unit to obtain the main heat exchange gas. The temperature of the main flue gas from the waste heat boiler is 500℃-600℃, and the flue gas flow rate is 15000 Nm³. 3 / h-22000Nm 3 / h; the temperature of the main heat exchange gas is not higher than 200℃; the cooling gas includes at least the combustion air and the outdoor cold air; wherein, the combustion air is introduced into the micro heat pipe array heat exchanger unit through the cold side flue gas inlet of the second gas-to-gas heat exchanger for heat exchange, and the heat-exchanged combustion air is introduced into the second combustion chamber; the outdoor cold air is heat-exchanged sequentially through the fourth gas-to-gas heat exchanger and the third gas-to-gas heat exchanger. The main heat exchange gas is introduced into the bag filter to collect particulate dust in the flue gas, obtaining primary dust-removed flue gas. The activated carbon in the bag filter has a particle size of 200-325 mesh and an injection velocity of 15-25 m / s. The primary dust-removed flue gas sequentially passes through the Venturi scrubber, the desulfurization oxidation tower, and the electrostatic precipitator to obtain secondary dust-removed flue gas, which is then introduced into the GGH heat exchanger to exchange heat with the denitrification flue gas introduced through the hot-side flue gas inlet of the GGH heat exchanger, obtaining the main flue gas after the GGH heat exchanger has been heated. This denitrification flue gas is obtained after denitrification in the SCR denitrification reactor. The denitrification flue gas is discharged from the hot-side flue gas outlet of the GGH heat exchanger after heat exchange. The temperature of the denitrification flue gas is 200℃-450℃, and the flue gas volume is 29000 Nm³. 3 / h -34000Nm 3 / h, the temperature of the flue gas at the hot side outlet of the GGH heat exchanger is 85℃-120℃; the temperature of the flue gas from the secondary dust removal process is 20℃-65℃, and the flue gas volume is 29000Nm³. 3 / h-32000Nm 3 / h, the temperature of the main flue gas after heating by the GGH heat exchanger is 185℃-390℃; the flue gas volume in the SCR denitrification reactor is 30000 Nm³. 3 / h-32000Nm 3 The reaction rate is 300℃-350℃ per hour; the nitrogen oxide content at the outlet is no more than 50 mg / Nm³. 3 ; After the GGH heat exchanger is heated, the main flue gas enters through the cold side flue gas inlet of the first gas-to-gas heat exchanger in the micro heat pipe array heat exchanger unit. After heat exchange, the heated main flue gas from the GGH heat exchanger is introduced into the SCR denitrification reactor for SCR denitrification to obtain the denitrified flue gas.

5. The method according to claim 4, characterized in that, The method further includes: The combustion-supporting air is annular flue gas; The temperature of the annular flue gas is 30℃-65℃; the flue gas volume is 500 Nm³. 3 / h -4000 Nm 3 / h; The temperature of the combustion air after heat exchange is 90℃-400℃.

6. The method according to claim 4, characterized in that, The method further includes: When the instantaneous concentration of nitrogen oxides in the secondary denitrification flue gas exceeds 250 mg / Nm³ 3 When the fourth-stage denitrification reaction site is activated; when the instantaneous concentration of nitrogen oxides in the second-stage denitrification flue gas is below 150 mg / Nm³. 3 Alternatively, if the temperature of the secondary denitrification flue gas is below 830°C, then ammonia injection will cease at the primary denitrification reaction site, the secondary denitrification reaction site, the tertiary denitrification reaction site, and the SNCR pipeline denitrification reaction site.

7. The method according to claim 6, characterized in that, The method further includes: The reaction temperature at the four-stage denitrification reaction sites is 830℃-875℃, and the ammonia injection rate is 390 L / h-430 L / h.

8. The method according to claim 4, characterized in that, The method further includes: The cooling gas also includes oxidizing mixed air and cooling protective gas; The oxidizing mixed air and the cooling protection air respectively enter the third gas-water heat exchanger for heat exchange and preheating, to obtain oxidizing mixed air preheated gas or cooling protection air preheated gas, which is then introduced into the tilting furnace.

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