Integrated treatment system for dust removal and denitration by using activated carbon in belt sintering pellet flue gas

Abstract

The utility model discloses a kind of belt roasting pellet flue gas activated carbon collaborative dust removal denitration integrated management system, belong to atmospheric pollution control field.The system includes belt roaster, regenerative blower, dust removal denitration integrated device, bag filter, main fan, activated carbon desulfurization and denitration device, chimney, drum dry circulating fan, heat exchanger and hot air circulating fan.Drum dry section flue gas is all sent back to cooling II section after heat exchange, realizes full recycling;Roasting section and heat soaking section regenerative flue gas is purified after dust removal denitration integrated device, part is used for activated carbon regeneration heat source, the rest is sent back to dry section and preheating section after heat exchange;Dry section and preheating section emission flue gas is treated after bag filter and activated carbon desulfurization and denitration device and reaches standard emission.The utility model realizes the effect of emission reduction and consumption reduction, compact structure, low operating cost by drum dry flue gas full cycle, dust removal denitration integration, waste heat regeneration and end collaborative denitration.

Description

Technical Field

[0001] This utility model belongs to the field of comprehensive flue gas treatment in air pollution control, and relates to industrial furnace flue gas treatment technology, specifically an integrated treatment system for flue gas from belt-type roasted pellets with activated carbon for dust removal and denitrification. Background Technology

[0002] Because increasing the proportion of blast furnace pellets can significantly reduce carbon emissions, improve blast furnace smelting efficiency, and lower production costs, steel companies have been strongly encouraged to adopt high-proportion pellet smelting in recent years. Among various pellet production technologies, belt roasting pellet technology has been widely used due to its high thermal efficiency, low energy consumption, compact process flow, small footprint, strong raw material adaptability, and excellent product quality.

[0003] The flue gas generated during the production of belt-type roasted pellets contains large amounts of air pollutants such as SO2, NOx, and particulate matter, which must be treated to meet emission standards before being released. Currently, conventional flue gas treatment technologies employ end-of-pipe treatment methods, involving dust removal, desulfurization, and denitrification before emission. Common integrated treatment technology pathways include: dust removal + wet desulfurization + SCR technology, semi-dry desulfurization + dust removal + SCR technology, and dust removal + activated carbon desulfurization and denitrification technology. The disadvantages of these technologies are that they all involve the treatment of the entire flue gas, resulting in large flue gas volumes, and the need for supplementary heating and the installation of gas-heating generators (GGHs) to recover heat, leading to large equipment sizes, high investment costs, high operating costs, and increased carbon emissions.

[0004] In recent years, some technical solutions have emerged that place the denitrification section inside the regenerating section of a belt roaster. This fully utilizes the temperature range of the regenerating section for denitrification, eliminating the need for supplementary heating of the end-of-pipe flue gas or the installation of a gas-cooled gas generator (GGH). Compared to conventional end-of-pipe flue gas treatment technologies, its main advantages are: smaller flue gas volume in the regenerating section, smaller treatment equipment; no need for supplementary heating or a GGH; and lower carbon emissions. Despite these significant improvements and advantages, these flue gas treatment technologies still have some drawbacks that need improvement: firstly, there are multiple emission points, requiring separate treatment of the exhaust gas in the drying section, resulting in a complex process; secondly, end-of-pipe desulfurization, whether using semi-dry or wet methods, does not have denitrification capabilities, meaning there are no remedial measures at the back end if the initial denitrification exceeds the standard. Furthermore, the dust removal and denitrification in the regenerating section use separate structures, resulting in a large footprint.

[0005] Chinese patent application CN120361722A discloses a system for denitrification using a belt roaster with regenerative air. This system uses the regenerative air from the belt roaster as a heat source to reheat the flue gas after desulfurization and heat exchange via a gas-to-gas (GGH) system, before proceeding with denitrification. This method still falls under the category of end-of-pipe flue gas treatment, where the regenerative air only serves as a preheating agent before denitrification.

[0006] Chinese patent application CN120426778A discloses a device and process for multi-pollutant staged treatment of flue gas from a chain grate machine to a rotary kiln pelletizing plant. This scheme performs denitrification and dust removal in an SCR system connected to the flue gas outlet of the preheating stage of the chain grate machine; desulfurization and dust removal in a semi-dry circulating fluidized bed system connected to the flue gas outlet of the drying stage of the chain grate machine; and desulfurization and dust removal in a dry desulfurization and dust removal system connected to the flue gas outlet of the drying stage of the chain grate machine. This system is only applicable to chain grate machine-rotary kiln pelletizing plants, and there are two downstream desulfurization flue gas outlets, making the process complex. Furthermore, neither the semi-dry nor dry desulfurization methods have denitrification capabilities, meaning there are no remedial measures at the downstream end if the upstream denitrification level slightly exceeds the limit.

[0007] Chinese patent application CN111318162A discloses a combined SCR and activated coke denitrification and desulfurization system and method for belt-type pellet roasting flue gas. In this scheme, the flue gas emitted from the belt roaster is discharged in two locations: the exhaust gas from the drying section is discharged after dust removal; the exhaust gas from the extraction and preheating sections requires dust removal, activated coke desulfurization, and further dust removal before discharge. This scheme involves numerous dust removal devices and a complex process. Furthermore, the exhaust gas from the drying section has a high moisture content, making it prone to bag clogging due to water vapor condensation when dust is removed separately; the regeneration of the activated carbon desulfurization system also requires additional fuel for heating. Utility Model Content

[0008] To address the problems in existing technologies, such as the need for separate treatment of exhaust gas in the drying section, the lack of remedial measures at the back end when the front-end denitrification slightly exceeds the standard, and the large footprint of the separate dust removal and denitrification structure in the regenerating section, this utility model provides an integrated treatment system for flue gas from belt-type roasted pellets, using activated carbon for synergistic dust removal and denitrification. This system eliminates the need for exhaust gas discharge by fully recycling the flue gas from the drying section to the cooling section II. It utilizes waste heat for regeneration by connecting the regenerated flue gas branch to the regeneration tower of the activated carbon desulfurization and denitrification device. Furthermore, it provides denitrification remediation by installing an activated carbon desulfurization and denitrification device at the end of the system and integrates dust removal and denitrification functions by installing an integrated dust removal and denitrification device on the regenerated flue gas pipeline. This achieves the treatment effects of emission reduction and energy saving, compact structure, and low operating cost.

[0009] The technical solution adopted by this utility model to solve its technical problem is:

[0010] A belt-type activated carbon-co-assisted dust removal and denitrification integrated treatment system for flue gas from calcined pellets is described. All components in this system are connected via flue gas ducts. The specific structure is as follows:

[0011] The outlet of the drying section of the belt roaster is connected to the first inlet of the heat exchanger via a drying circulation fan. The first outlet of the heat exchanger is connected to the inlet of the cooling section II of the belt roaster, forming a flue gas circulation structure for the drying section.

[0012] The roasting section and the homogenization section outlet of the belt roaster are connected to the second inlet of the heat exchanger via a regenerative fan. The second outlet of the heat exchanger is connected to the drying section and the preheating section inlet of the belt roaster, forming a regenerative flue gas circulation structure. The circulating flue gas pipeline of the regenerative flue gas circulation structure is equipped with an integrated dust removal and denitrification device for dust removal and denitrification of the regenerative flue gas.

[0013] The flue gas pipeline branch between the regenerating fan and the second inlet of the heat exchanger is connected to the hot air inlet of the heating section of the regeneration tower of the activated carbon desulfurization and denitrification device. The hot air outlet of the heating section of the regeneration tower is returned to the flue gas pipeline between the regenerating fan and the second inlet of the heat exchanger via a hot air circulation fan, and the return point is located downstream of the flue gas flow direction of the outlet point, forming a regeneration heat source circulation structure.

[0014] The outlets of the drying section and preheating section of the belt roaster are sequentially connected to a bag filter, a main fan, an activated carbon desulfurization and denitrification device, and a chimney, forming an end-of-pipe flue gas treatment structure.

[0015] Furthermore, the integrated dust removal and denitrification device is internally equipped with a high-temperature resistant metal filter bag for dust removal and an SCR denitrification catalyst for denitrification.

[0016] Furthermore, the SCR denitrification catalyst adopts a modular embedded structure and can be detachably inserted into the mounting slot inside the integrated dust removal and denitrification device.

[0017] Furthermore, the integrated dust removal and denitrification device is located at position A: installed on the flue gas duct at the front end of the regenerating fan, and the denitrification catalyst is a high-temperature, high-sulfur, low-dust SCR denitrification catalyst.

[0018] Furthermore, the integrated dust removal and denitrification device is located at B: installed on the flue gas duct between the regenerating fan and the second inlet of the heat exchanger, and the denitrification catalyst is a high-temperature, high-sulfur, low-dust SCR denitrification catalyst.

[0019] Furthermore, the integrated dust removal and denitrification device is located at position C: installed on the flue gas duct at the rear end of the second outlet of the heat exchanger, and the denitrification catalyst is a medium-low temperature type high sulfur and low dust SCR denitrification catalyst.

[0020] Furthermore, the activated carbon desulfurization and denitrification device uses activated carbon or activated coke as the desulfurization and denitrification catalyst, and the bed adopts a cross-flow layered composite bed structure. Each bed includes at least three layers arranged sequentially from front to back along the flue gas flow direction, namely a dust removal and desulfurization zone, a deep desulfurization zone, and an auxiliary denitrification zone.

[0021] Furthermore, ammonia injection pipes are fixedly installed in the upper half of the flue gas inlet and the auxiliary denitrification zone at the rear of the bed of the activated carbon desulfurization and denitrification device. The ammonia injection pipes are equipped with swirling flow equalization nozzles for injecting ammonia-air mixed gas to assist in denitrification.

[0022] Furthermore, the hot air circulating fan adopts a variable frequency motor, which is used to adjust the hot air return flow rate at the hot air outlet of the heating section of the regeneration tower of the activated carbon desulfurization and denitrification device by changing the frequency.

[0023] Furthermore, the bag filter is a pulse jet bag filter.

[0024] The beneficial effects of this utility model include:

[0025] (1) By optimizing the flue gas circulation structure of the drying section, the flue gas of the drying section is returned to the cooling section II of the belt roaster after heat exchange, realizing the full recycling of the flue gas of the drying section, eliminating the external discharge path of the flue gas of the drying section, reducing the number of flue gas emission points, and effectively reducing the total amount of pollutant emissions.

[0026] (2) Using part of the flue gas drawn out from the reheat section as the heat source of the regeneration tower of the activated carbon desulfurization and denitrification device, there is no need to configure an additional heating fuel system. The heat required for activated carbon regeneration can be met by using the waste heat of the flue gas, which greatly reduces the system's operating energy consumption and operating costs, while avoiding the secondary pollution problem caused by the combustion of additional fuel.

[0027] (3) The dust removal and denitrification integrated device is used to replace the independent dust collector and denitrification reactor in the existing technology. The dust removal and denitrification functions are integrated into the same device, which simplifies the system composition, reduces the equipment footprint and investment cost, and realizes the synergistic treatment of particulate matter and nitrogen oxides in the regenerated flue gas, improves the flue gas treatment efficiency, and effectively overcomes the problems of equipment redundancy and large footprint in the existing technology. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the overall structure of this utility model.

[0029] In the diagram: 1. Belt roaster; 2. Integrated dust removal and denitrification device; 3. Bag filter; 4. Main fan; 5. Activated carbon desulfurization and denitrification device; 6. Chimney; 101. Regenerating fan; 102. Heat exchanger; 103. Blowing and drying circulating fan; 104. Hot air circulating fan. Detailed Implementation

[0030] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0031] In the description of this utility model, it should be noted that the terms "upper," "lower," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the technical features involved in the different embodiments of this utility model described below can be combined with each other as long as they do not conflict with each other.

[0032] This utility model provides an integrated treatment system for flue gas from belt-type roasted pellets, using activated carbon for dust removal and denitrification. By optimizing the flue gas circulation structure, integrating core devices, and utilizing waste heat from the flue gas for regeneration, it achieves emission reduction, energy saving, and compact treatment effects while ensuring treatment efficiency.

[0033] Example 1: First, the process flow of the belt roaster is briefly described (existing technology; for ease of understanding, this process is briefly introduced). The belt roaster is the core equipment for roasting iron concentrate powder into pellets. Along the operating direction, it is divided into a drying section, a preheating section, a roasting section, a homogenizing section, and a cooling section. The preheating section can be further divided into preheating section I and preheating section II, and the cooling section includes cooling section I, cooling section II, and cooling section III. After the green pellets enter the belt roaster, they first pass through the drying section to remove some moisture, then through the preheating section for further drying, followed by preheating in the preheating section. Then, they undergo high-temperature roasting in the roasting and homogenizing sections to solidify the pellets. Finally, they are cooled in the cooling section and output as finished pellets. The roasting and homogenizing sections are the main areas for SO2 and NOx generation in the flue gas. The reheated flue gas discharged from these areas has a high temperature and high waste heat utilization value. The exhaust gas discharged from the drying section has a high moisture content and a low temperature. The flue gas discharged from the drying section and the preheating section is the final emission gas, which needs to be treated to meet emission standards.

[0034] refer to Figure 1 This embodiment discloses an integrated flue gas treatment system for belt-type roasted pellets, incorporating activated carbon for dust removal and denitrification. The system includes a belt roaster 1, a regenerating fan 101, an integrated dust removal and denitrification device 2, a bag filter 3, a main fan 4, an activated carbon desulfurization and denitrification device 5, a chimney 6, a forced-drying circulating fan 103, a heat exchanger 102, and a hot air circulating fan 104. All components are connected via flue gas ducts to form a complete flue gas treatment and circulation structure. The specific structure is as follows:

[0035] The drying section flue gas circulation structure. The outlet of the drying section of the belt roaster 1 is connected to the inlet of the drying circulation fan 103, the outlet of the drying circulation fan 103 is connected to the first inlet of the heat exchanger 102, and the first outlet of the heat exchanger 102 is connected to the inlet of the cooling section II of the belt roaster 1.

[0036] The exhaust gas discharged from the drying section is sent to the heat exchanger 102 by the drying circulation fan 103, where it exchanges heat with the high-temperature regenerated flue gas from the regenerating section. After being heated, it is sent back to the cooling section II of the belt roaster 1 as a cooling medium, realizing the full recycling of the flue gas in the drying section and eliminating the need for additional flue gas discharge.

[0037] Regenerative flue gas circulation structure. The outlets of the roasting section and the homogenizing section of the belt roaster 1 are connected to the inlet of the regenerative fan 101. The outlet of the regenerative fan 101 is connected to the second inlet of the heat exchanger 102. The second outlet of the heat exchanger 102 is connected to the inlet of the drying section and the preheating section of the belt roaster 1.

[0038] In this embodiment, the integrated dust removal and denitrification device 2 is preferably installed on the flue gas duct at the front end of the regenerating blower 101. Figure 1 (Position A in the middle). This device integrates high-temperature resistant metal filter bags and an SCR denitrification catalyst. The high-temperature resistant metal filter bags are used to remove particulate matter from flue gas, with a continuous operating temperature of not less than 500℃ and an instantaneous operating temperature of not less than 650℃. The particulate matter content in the gas after dust removal is not greater than 20 mg / m³. 3 The treated flue gas particulate matter content meets the requirements of subsequent processes. The SCR denitrification catalyst is used to remove nitrogen oxides from the flue gas. The SCR denitrification catalyst adopts a modular embedded structure and can be detachably inserted into the mounting slot inside the device for easy replacement and maintenance.

[0039] The regenerated flue gas discharged from the roasting section and the homogenizing section is transported by the regenerated blower 101 and first enters the integrated dust removal and denitrification device 2 for treatment. After being treated by the integrated dust removal and denitrification device 2, the regenerated flue gas is sent to the second inlet of the heat exchanger 102 through the regenerated blower 101 to exchange heat with the low-temperature waste gas from the drying section. After the heat exchange, the temperature decreases, and then it is sent back to the inlet of the drying section and the preheating section of the belt roaster 1 from the second outlet of the heat exchanger 102 as a heat source for drying and preheating, forming a regenerated flue gas circulation.

[0040] Regenerative heat source circulation structure. A branch line is drawn from the flue gas duct between the regenerating fan 101 and the second inlet of the heat exchanger 102, and this branch line is connected to the hot air inlet of the heating section of the regeneration tower of the activated carbon desulfurization and denitrification device 5. The hot air outlet of the heating section of the regeneration tower is connected to the inlet of the hot air circulating fan 104, and the outlet of the hot air circulating fan 104 is reconnected to the flue gas duct between the regenerating fan 101 and the second inlet of the heat exchanger 102, with the reconnection point located downstream of the flue gas flow direction of the outlet point.

[0041] A portion of the high-temperature regenerated flue gas drawn from the regenerated flue gas duct enters the heating section of the regeneration tower of the activated carbon desulfurization and denitrification device 5, providing heat for activated carbon regeneration. The hot air after heat exchange is sent back downstream of the main flue gas outlet point by the hot air circulation fan 104, mixes with the remaining regenerated flue gas, and continues to enter the heat exchanger 102 to form a regeneration heat source cycle.

[0042] Preferably, the hot air circulating fan 104 is a variable frequency motor, which adjusts the flow rate of the circulating hot air drawn from the heating section of the regeneration tower by changing the frequency, so that the temperature of the flue gas at the outlet of the heating section of the regeneration tower is between 280°C and 330°C.

[0043] End-of-pipe flue gas treatment structure. The outlets of the drying section and preheating section of the belt calciner 1 are connected to the inlet of the bag filter 3. The outlet of the bag filter 3 is connected to the inlet of the main fan 4. The outlet of the main fan 4 is connected to the flue gas inlet of the activated carbon desulfurization and denitrification device 5. The flue gas outlet of the activated carbon desulfurization and denitrification device 5 is connected to the chimney 6, thereby achieving end-of-pipe flue gas desulfurization, auxiliary denitrification, and emission compliance.

[0044] The exhaust gas from the drying and preheating sections first enters the bag filter 3 for dust removal. Preferably, the bag filter 3 is a pulse-jet bag filter, which effectively removes particulate matter from the exhaust gas, ensuring that the particulate matter content in the gas after dust removal is no more than 10 mg / m³. 3 The flue gas after dust removal is sent to the activated carbon desulfurization and denitrification device 5 via the main fan 4.

[0045] The activated carbon desulfurization and denitrification unit 5 uses activated carbon or activated coke as the desulfurization and denitrification catalyst. Its bed adopts a cross-flow, layered composite bed structure. Each bed includes at least three zones arranged sequentially from front to back along the flue gas flow direction: a dust removal and desulfurization zone, a deep desulfurization zone, and an auxiliary denitrification zone. SO2 in the flue gas is efficiently removed in the dust removal and desulfurization zone and the deep desulfurization zone, while particulate matter in the flue gas is further captured. Ammonia injection pipes are fixedly installed in the upper part of the flue gas inlet and in the auxiliary denitrification zone at the rear of the bed. These pipes are equipped with swirling flow equalization nozzles for injecting ammonia-air mixed gas to assist denitrification and reduce ammonia escape. The purified flue gas treated by the activated carbon desulfurization and denitrification unit is discharged through a chimney in compliance with emission standards.

[0046] This system achieves comprehensive treatment of flue gas from belt-roasted pellet mills through the coordinated operation of four cyclic structures:

[0047] The low-temperature, high-humidity exhaust gas generated in the drying section is not directly discharged. Instead, it is heated by heat exchange and then sent back to the cooling section II. This utilizes the waste heat of the exhaust gas and avoids the process complexity caused by treating the exhaust gas separately.

[0048] The high-temperature regenerated flue gas generated in the roasting and soaking sections is purified by the integrated dust removal and denitrification device. Part of it is used as a heat source for activated carbon regeneration, and the other part is returned to the drying and preheating sections after heat exchange as a heat source for drying and preheating, thus realizing the cascade utilization of flue gas waste heat.

[0049] The flue gas at the end is treated by bag filter and activated carbon desulfurization and denitrification device to meet emission standards. The activated carbon desulfurization and denitrification device has an auxiliary denitrification function, which can provide remedy when the front-end denitrification effect is insufficient to ensure that the emission meets the standards.

[0050] Example 2: Taking the flue gas treatment system of a belt roaster with an annual output of 2.4 million tons of pellets as an example, the specific implementation of this utility model will be described in detail with reference to the accompanying drawings.

[0051] During the roasting process of iron ore pellets, SO2 and NOx are mainly generated in the roasting and soaking sections of the belt roaster. The regenerated flue gas drawn from the roasting and soaking sections has a temperature of approximately 420℃ and a flow rate of 35 × 10⁻⁶. 4 Nm 3 / h, NOx content is 700mg / m³ 3 .

[0052] After being drawn from the roasting and homogenizing sections of the belt calciner 1, the reheated flue gas enters the integrated dust removal and denitrification device 2. In this device, the flue gas first passes through high-temperature resistant metal filter bags to remove most of the particulate matter, reducing the particulate matter content to 20 mg / m³ after treatment. 3 The following steps are followed: Ammonia-air mixed gas is then injected, and NOx is removed under the action of the SCR denitrification catalyst. After treatment, the NOx content is reduced to 82 mg / m³. 3 .

[0053] After being treated by the integrated dust removal and denitrification device 2, the regenerated flue gas passes through the regenerated fan 101, and a portion of it (approximately 10 × 10) is then discharged. 4 Nm 3 The flue gas ( / h) is introduced into the heating section of the regeneration tower of the activated carbon desulfurization and denitrification unit 5 as a heat source for activated carbon regeneration. After heat exchange in the regeneration tower, the temperature of this part of the flue gas drops to about 300°C. It is then sent back to the downstream of the flue outlet point between the regenerating fan 101 and the heat exchanger 102 by the hot air circulation fan 104, where it mixes with the remaining regenerating flue gas and enters the heat exchanger 102 together.

[0054] The exhaust gas temperature from the drying section of belt roaster 1 is 120℃, and the flow rate is 30×10⁻⁶. 4 Nm 3 The exhaust gas from the drying section is fed into the heat exchanger 102 via the blower 103. In the heat exchanger 102, the exhaust gas from the drying section exchanges heat with the previously mixed regenerated flue gas. After heat exchange, the exhaust gas from the drying section is heated to approximately 200°C and sent to the cooling section II of the belt roaster 1 as a cooling medium; the regenerated flue gas is cooled to approximately 340°C and sent back to the drying section, preheating section I, and preheating section II of the belt roaster 1 as a heat source for drying and preheating.

[0055] The exhaust gas from the drying section, preheating section I, and preheating section II of the belt roaster 1 has a flow rate of 75 × 10⁻⁶. 4 Nm 3 / h, temperature approximately 140℃, SO2 content 1200mg / m³ 3The NOx content was 39.2 mg / m³. 3 The emitted flue gas first enters bag filter 3 for dust removal, after which the particulate matter content is reduced to 10 mg / m³. 3 The flue gas after dust removal is sent to the activated carbon desulfurization and denitrification device 5 via the main fan 4.

[0056] In the activated carbon desulfurization and denitrification unit 5, SO2 in the flue gas is efficiently removed by activated carbon (or activated coke). Simultaneously, an ammonia-air mixture is injected into the upper part of the flue gas inlet and the auxiliary denitrification zone at the rear of the bed to assist in NOx removal; the denitrification efficiency in this section can reach 20%~40%. The purified flue gas after treatment by the activated carbon desulfurization and denitrification unit 5 is discharged through chimney 6. Assuming a denitrification efficiency of 30%, the final NOx content in the emitted flue gas is approximately 27 mg / m³. 3 SO2 content decreased to 10 mg / m³ 3 The following particulate matter content is below 10 mg / m³ 3 The following fully meet the requirements of the ultra-low emission standards for the steel industry.

[0057] Since the flue gas flow rate in the regenerating section is much smaller than that in the end-of-pipe emission section, denitrification in the regenerating section can significantly reduce the amount of SCR denitrification catalyst required, thus lowering equipment investment. Simultaneously, the integrated dust removal and denitrification device is compact and requires little floor space. Most particulate matter is removed in the regenerating section, significantly reducing the processing load on the end-of-pipe baghouse dust collector. The high-moisture-content flue gas from the drying section is no longer discharged but is returned to the cooling section II for recycling after heat exchange, reducing total flue gas emissions. The waste heat from the regenerating flue gas provides heat for activated carbon regeneration, eliminating the need for additional heating fuel and saving energy consumption.

[0058] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the protection scope of this invention.

Claims

1. A belt-type activated carbon-co-assisted dust removal and denitrification integrated treatment system for flue gas from calcined pellets, wherein the connections of all equipment in the system are achieved through flue gas ducts, characterized in that... The specific structure is as follows: The outlet of the drying section of the belt roaster (1) is connected to the first inlet of the heat exchanger (102) via the drying circulation fan (103), and the first outlet of the heat exchanger (102) is connected to the inlet of the cooling section II of the belt roaster (1), forming a drying section flue gas circulation structure. The outlets of the roasting section and the homogenization section of the belt roaster (1) are connected to the second inlet of the heat exchanger (102) via a regenerating fan (101). The second outlet of the heat exchanger (102) is connected to the inlet of the drying section and the preheating section of the belt roaster (1), forming a regenerating flue gas circulation structure. The circulating flue gas pipeline of the regenerating flue gas circulation structure is equipped with an integrated dust removal and denitrification device (2) for dust removal and denitrification of the regenerating flue gas. The flue gas pipeline branch between the regenerating blower (101) and the second inlet of the heat exchanger (102) is connected to the hot air inlet of the regeneration tower heating section of the activated carbon desulfurization and denitrification device (5). The hot air outlet of the regeneration tower heating section is returned to the flue gas pipeline between the regenerating blower (101) and the second inlet of the heat exchanger (102) via the hot air circulation fan (104), and the return point is located downstream of the flue gas flow direction of the outlet point, forming a regeneration heat source circulation structure. The outlets of the drying section and preheating section of the belt roaster (1) are connected in sequence to the bag filter (3), the main fan (4), the activated carbon desulfurization and denitrification device (5) and the chimney (6) to form an end-of-pipe flue gas treatment structure.

2. The integrated treatment system for flue gas from belt-type roasted pellets with activated carbon for synergistic dust removal and denitrification as described in claim 1, characterized in that, The dust removal and denitrification integrated device (2) is internally equipped with a high-temperature resistant metal filter bag for dust removal and an SCR denitrification catalyst for denitrification.

3. The integrated treatment system for flue gas from belt-type roasted pellets with activated carbon for synergistic dust removal and denitrification as described in claim 2, characterized in that, The SCR denitrification catalyst adopts a modular embedded structure and can be detachably inserted into the mounting slot inside the dust removal and denitrification integrated device (2).

4. The integrated treatment system for flue gas from belt-type roasted pellets with activated carbon for synergistic dust removal and denitrification as described in any one of claims 1-3, characterized in that, The integrated dust removal and denitrification device (2) is located at A: installed on the flue gas duct at the front end of the regenerating blower (101), and the denitrification catalyst is a high-temperature, high-sulfur, low-dust SCR denitrification catalyst.

5. The integrated treatment system for flue gas from belt-type roasted pellets with activated carbon for synergistic dust removal and denitrification as described in any one of claims 1-3, characterized in that, The integrated dust removal and denitrification device (2) is located at B: installed on the flue gas duct between the regenerating fan (101) and the second inlet of the heat exchanger (102). The denitrification catalyst is a high-temperature, high-sulfur, low-dust SCR denitrification catalyst.

6. The integrated treatment system for flue gas from belt-type roasted pellets with activated carbon for synergistic dust removal and denitrification as described in any one of claims 1-3, characterized in that, The integrated dust removal and denitrification device (2) is located at C: installed on the flue gas pipeline at the second outlet of the heat exchanger (102), and the denitrification catalyst is a medium-low temperature type high sulfur and low dust SCR denitrification catalyst.

7. The integrated treatment system for flue gas from belt-type roasted pellets with activated carbon for synergistic dust removal and denitrification as described in claim 1, characterized in that, The activated carbon desulfurization and denitrification device (5) uses activated carbon or activated coke as the desulfurization and denitrification catalyst. The bed adopts a cross-flow layered composite bed structure. Each bed includes at least three layers arranged sequentially from front to back along the flue gas flow direction, namely the dust removal and desulfurization zone, the deep desulfurization zone, and the auxiliary denitrification zone.

8. The integrated treatment system for flue gas from belt-type roasted pellets with activated carbon for synergistic dust removal and denitrification as described in claim 7, characterized in that, The activated carbon desulfurization and denitrification device (5) has ammonia injection pipes fixedly installed in the upper half of the flue gas inlet and the auxiliary denitrification zone at the rear of the bed. The ammonia injection pipes are equipped with swirling flow equalization nozzles for injecting ammonia-air mixed gas to assist in denitrification.

9. The integrated treatment system for flue gas from belt-type roasted pellets with activated carbon for synergistic dust removal and denitrification as described in claim 1, characterized in that, The hot air circulating fan (104) is a variable frequency motor, which is used to adjust the hot air flow rate of the hot air outlet of the heating section of the activated carbon desulfurization and denitrification device (5) by changing the frequency.

10. The integrated treatment system for flue gas from belt-type roasted pellets with activated carbon for synergistic dust removal and denitrification as described in claim 1, characterized in that, The bag filter (3) is a pulse jet bag filter.

Images