Flue gas treatment system

Abstract

According to the flue gas treatment system provided by the embodiment of the invention, the flue gas pretreatment system is used for pretreating the flue gas of the circulating fluidized bed to realize uniform distribution of the flow velocity of the flue gas, so that the stability of subsequent treatment is improved; the high-temperature electrostatic dust removal system is connected with the flue gas pretreatment system through a pipeline and used for performing high-temperature dust removal on dust-containing gas, generating first clean gas after dust removal and outputting the first clean gas, so that efficient dust removal is realized while a front cooling system is not additionally arranged, the dust removal efficiency is improved, and the flue gas dust removal cost of the circulating fluidized bed is reduced; the complex process of firstly cooling and then dedusting in the prior art is improved; the waste heat recovery system is connected with the high-temperature electrostatic dust removal system through a pipeline and used for conducting waste heat recovery treatment on the first clean gas, and cooled second clean gas is generated and output, so that flue gas heat energy is recycled, and system energy consumption is reduced. And the dust collection system is used for collecting dust generated by the high-temperature electrostatic dust removal system.

Description

Technical Field

[0001] This invention relates to the field of flue gas treatment technology, and in particular to a flue gas treatment system. Background Technology

[0002] Currently, conventional baghouse dust collectors suffer from insufficient adaptability due to the low temperature tolerance of their filter bags, making them unsuitable for medium- and high-temperature flue gas conditions. On the one hand, the upper limit of the temperature tolerance of commonly used filter bag materials is usually no more than 350℃, while the flue gas temperature range of the project is 350–750℃. If this is forced, expensive high-temperature resistant filter bags must be replaced, and their service life will be significantly shortened. On the other hand, the high dust concentration in the flue gas easily leads to filter bag clogging, requiring the addition of pretreatment equipment, which increases system resistance and operating energy consumption. Furthermore, the oxidation and aging of filter bags will be accelerated in an oxygen-rich environment.

[0003] However, existing technologies rely on forced cooling of flue gas, resulting in a cumbersome system: to meet the inlet temperature requirements of conventional baghouse dust collectors, current processes are forced to install multi-stage heat exchange equipment before dust removal to gradually cool the high-temperature flue gas. Although this cooling system can recover some sensible heat, the overall cost is high: equipment investment increases significantly, the system process becomes more complex with more pipelines, the total resistance rises significantly, leading to a substantial increase in induced draft fan energy consumption. In essence, this forms a waste heat recovery method that comes at the cost of high equipment investment and operating costs. Summary of the Invention

[0004] In view of the above problems, embodiments of the present invention are proposed to provide a flue gas treatment system that overcomes or at least partially solves the above problems.

[0005] This invention provides a flue gas treatment system, which includes: A flue gas pretreatment system is used to receive flue gas from a circulating fluidized bed and pretreat the flue gas to generate dust-laden gas with uniform flow rate and output it. A high-temperature electrostatic precipitator system is connected to the flue gas pretreatment system and is used to remove dust from the dust-laden gas at high temperature, generate the first clean gas after dust removal, and output it. The waste heat recovery system is connected to the high-temperature electrostatic dust removal system and is used to recover waste heat from the first clean gas to generate a cooled second clean gas and output it. A dust collection system, connected to the high-temperature electrostatic precipitator system, is used to collect the dust generated by the high-temperature electrostatic precipitator system.

[0006] Optionally, the flue gas pretreatment system includes: A horizontal cyclone separator is used to receive flue gas and perform cyclone dust removal treatment on the flue gas to separate coarse particles in the flue gas from the dust-laden gas. An airflow equalization device is connected to the horizontal cyclone separator via a pipeline. It is used to receive the dust-laden gas and uniformly distribute the dust-laden gas to generate dust-laden gas with a uniform flow rate.

[0007] Optionally, the high-temperature electrostatic precipitator system includes: The first electric field generating device is connected to the flue gas pretreatment system through a pipeline and is used to receive the dust-laden gas so that the dust particles in the dust-laden gas are charged and the charged dust-laden gas is output. The second electric field generating device is connected to the first electric field generating device and is used to receive the charged dust-laden gas to capture dust particles in the charged dust-laden gas and output the first clean gas after dust removal. An air compressor is used to receive air and compress the air to generate compressed air; A dust removal controller, connected to the air compressor, is used to receive the compressed air; Several pulse valves are connected to the dust removal controller and the anode plate of the first electric field generating device or the anode plate of the second electric field generating device. When the preset dust removal conditions are met, the pulse valve receives the compressed air output by the dust removal controller and opens the gas valve to spray the compressed air onto the anode plate of the first electric field generating device or the anode plate of the second electric field generating device, so that the dust attached to the anode plate of the first electric field generating device or the anode plate of the second electric field generating device falls off.

[0008] Optionally, a first pressure sensor is provided at the inlet front end of the first electric field generating device; a second pressure sensor is provided at the outlet rear end of the second electric field generating device. The preset dust removal conditions include: the difference between the pressure value detected by the first pressure sensor and the pressure value detected by the second pressure sensor is greater than a preset pressure difference threshold.

[0009] Optionally, the waste heat recovery system includes: An explosion-proof control device is used to receive the first clean gas output by the high-temperature electrostatic dust removal system, detect the oxygen content in the first clean gas, and output the first clean gas when the oxygen content is greater than a preset oxygen content threshold. A heat exchanger, connected to the explosion-proof control device via a pipeline, is used to receive air and the first clean gas output by the explosion-proof control device, so that the air and the first clean gas exchange heat and generate the cooled second clean gas.

[0010] Optionally, the explosion-proof control device includes: An oxygen content monitor is used to detect the oxygen content in the first clean gas; An outlet is used to output the first clean gas to the heat exchanger; The nitrogen injection module is activated and the outlet is closed when the oxygen content exceeds a preset oxygen content threshold.

[0011] Optionally, the dust collection system includes: A horizontal screw conveyor is connected to the high-temperature electrostatic precipitator system via a pipeline and is used to receive dust from the high-temperature electrostatic precipitator system. The ash silo, connected to the horizontal screw conveyor via a pipe, is used to receive and store the dust output from the horizontal screw conveyor.

[0012] Optionally, the horizontal cyclone separator includes an air inlet and an air outlet; the air inlet of the horizontal cyclone separator is used to receive the flue gas; the air outlet of the horizontal cyclone separator is used to output the dust-laden gas. The airflow equalization device includes an air inlet and an air outlet; the air inlet of the airflow equalization device is connected to the horizontal cyclone separator through a pipe for receiving the dust-laden gas; the air outlet of the airflow equalization device is connected to the high-temperature electrostatic dust removal system through a pipe for outputting the dust-laden gas with a uniform flow rate.

[0013] Optionally, the air compressor includes an air inlet and an air outlet; the air inlet of the air compressor is used to receive air; the air outlet of the air compressor is connected to the air inlet of the dust removal controller via a pipe. The dust removal controller includes an air inlet, a first air outlet, and a second air outlet; the air inlet of the dust removal controller is connected to the air outlet of the air compressor via a pipe; the first air outlet of the dust removal controller is connected to the air inlet of a plurality of pulse valves connected to the first electric field generating device via a pipe; the second air outlet of the dust removal controller is connected to the air inlet of a plurality of pulse valves connected to the second electric field generating device via a pipe. The plurality of pulse valves include an air inlet and an air outlet; the air inlet of each pulse valve connected to the first electric field generating device is connected to the first air outlet of the dust removal controller via a pipe, for receiving the compressed air output by the dust removal controller; the air inlet of each pulse valve connected to the second electric field generating device is connected to the air outlet of the dust removal controller via a pipe, for receiving the compressed air output by the dust removal controller; the air outlet of each pulse valve is connected to the air inlet on the anode plate of the first electric field generating device or the anode plate of the second electric field generating device via a pipe, for outputting the compressed air to the anode plate; The first electric field generating device includes a first air inlet, a second air inlet, and an air outlet; the air inlet of the first electric field generating device is connected to the flue gas pretreatment system via a pipe for receiving the dust-laden gas; the air outlet of the first electric field generating device is connected to the air inlet of the second electric field generating device via a pipe for outputting the charged dust-laden gas; the second air inlet of the first electric field generating device is connected to the air outlet of the pulse valve for receiving the compressed air output from the air inlet of the pulse valve to cause the dust on the anode plate to fall off. The second electric field generating device includes a first air inlet, a second air inlet, and an air outlet; the first air inlet of the second electric field generating device is connected to the air outlet of the first electric field generating device via a pipe, and is used to receive the charged dust-laden gas; the air outlet of the second electric field generating device is connected to the waste heat recovery system via a pipe, and is used to output the first clean gas; the second air inlet of the second electric field generating device is used to connect to the air outlet of the pulse valve, and is used to receive the compressed air output from the air inlet of the pulse valve to make the dust on the anode plate fall off.

[0014] Optionally, the explosion-proof control device includes an air inlet and an air outlet; the air inlet of the explosion-proof control device is connected to the high-temperature electrostatic dust removal system through a pipe for receiving the first clean gas; the air outlet of the explosion-proof control device is connected to the first air inlet of the heat exchanger through a pipe for outputting the first clean gas. The heat exchanger includes a first air inlet, a second air inlet, and an air outlet; the first air inlet of the heat exchanger is connected to the air outlet of the explosion-proof control device via a pipe, and is used to receive the first clean gas; the second air inlet of the heat exchanger is used to receive air; and the air outlet of the heat exchanger is used to output the first clean gas.

[0015] The embodiments of this invention include the following advantages: A flue gas pretreatment system is used to pretreat the flue gas in the circulating fluidized bed to achieve a uniform distribution of flue gas velocity, thereby improving the stability of subsequent treatment; a high-temperature electrostatic precipitator is connected to the flue gas pretreatment system via pipeline to perform high-temperature dust removal on the dust-laden gas, generating a first clean gas after dust removal and outputting it, thus achieving efficient dust removal without the need for an additional pre-cooling system, improving dust removal efficiency, reducing the cost of flue gas dust removal in the circulating fluidized bed, improving the complex process of prior cooling followed by dust removal in the prior art, achieving the improvement goal of small footprint, and the high-temperature electrostatic precipitator system has strong site adaptability and can adapt to compact sites; a waste heat recovery system is connected to the high-temperature electrostatic precipitator system via pipeline to perform waste heat recovery treatment on the first clean gas, generating a second clean gas after cooling and outputting it, thereby realizing the recovery and utilization of flue gas heat energy and reducing system energy consumption; a dust collection system is used to collect the dust generated by the high-temperature electrostatic precipitator system. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a process flow diagram of a flue gas treatment system provided in an embodiment of the present invention; Figure 2 This is a process flow diagram of another flue gas treatment system provided in an embodiment of the present invention.

[0018] Explanation of reference numerals in the attached figures: 10-Flue gas pretreatment system, 20-High temperature electrostatic dust removal system, 30-Waste heat recovery system, 40-Dust collection system, 101-Horizontal cyclone separator, 102-Airflow distribution device, 201-First electric field generating device, 202-Second electric field generating device, 203-Air compressor, 204-Dust removal controller, 205-Several pulse valves, 301-Explosion-proof control device, 302-Heat exchanger, 401-Horizontal screw conveyor, 402-Ash silo, 3011-Oxygen content monitor, 3012-Nitrogen injection module. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] The terms "first," "second," etc., used in the specification and claims of this invention are used to distinguish similar objects and are not used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the invention can be implemented in orders other than those illustrated or described herein. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0021] In high-temperature flue gas purification processes, the selection of dust removal equipment is crucial to determining the system's economy and reliability. Currently, conventional baghouse dust collectors are unable to directly cope with medium- and high-temperature flue gas environments due to the limited temperature tolerance of their filter bags: the upper limit of the temperature tolerance of their commonly used materials (such as polyphenylene sulfide) is usually no higher than 350℃, while the actual flue gas temperature is often in the range of 350-750℃. If used directly, they need to be replaced with expensive high-temperature resistant filter bags such as polytetrafluoroethylene, and their service life is significantly shortened. At the same time, the high dust concentration in the flue gas (usually 150-300g / Nm³) easily leads to filter bag clogging, requiring the addition of pretreatment equipment, which not only increases the system resistance by 500-800Pa and energy consumption by about 15%, but also accelerates the oxidation and aging process of the filter bags in an oxygen-rich environment.

[0022] Current technologies generally rely on forced cooling of flue gas, resulting in complex system structures. To accommodate the safe inlet temperature of baghouse dust collectors, which typically does not exceed 260°C, current processes necessitate adding multi-stage heat exchange systems such as air preheaters, waste heat boilers, and heat pipe heat exchangers before dust removal to gradually cool the high-temperature flue gas. While such cooling systems can recover some sensible heat for steam production, they come at a significant cost: equipment investment increases by more than 30%, system flow is prolonged, connecting pipelines are complex, overall resistance reaches 1500-2000 Pa, and the energy consumption of induced draft fans rises sharply. Essentially, this constitutes a waste heat recovery method at the expense of high equipment investment and operating costs. Therefore, developing a highly efficient dust removal technology that can directly adapt to medium-high temperature, high concentration, and oxygen-rich conditions, while avoiding the system complexity and energy efficiency losses caused by forced cooling, has become a critical issue urgently needing to be addressed in the field of flue gas purification.

[0023] One of the core concepts of this invention is the use of a flue gas pretreatment system to pretreat the flue gas in a circulating fluidized bed, thereby achieving a uniform distribution of flue gas velocity and improving the stability of subsequent treatment. A high-temperature electrostatic precipitator is connected to the flue gas pretreatment system via pipeline to perform high-temperature dust removal on the dust-laden gas, generating a first clean gas after dust removal and outputting it. This achieves efficient dust removal without the need for an additional pre-cooling system, improving dust removal efficiency, reducing the cost of flue gas dust removal in the circulating fluidized bed, and improving upon the complex process of prior cooling followed by dust removal in existing technologies. It also achieves the goal of a smaller footprint. Furthermore, this high-temperature electrostatic precipitator system is highly adaptable to compact sites. A waste heat recovery system is connected to the high-temperature electrostatic precipitator system via pipeline to recover waste heat from the first clean gas, generating a second clean gas after cooling and outputting it, thereby realizing the recovery and utilization of flue gas heat energy and reducing system energy consumption. A dust collection system is used to collect the dust generated by the high-temperature electrostatic precipitator system.

[0024] Figure 1 This is a process flow diagram of a flue gas treatment system provided in an embodiment of the present invention.

[0025] like Figure 1 As shown, the system may specifically include the following: The flue gas pretreatment system 10 is used to receive the flue gas from the circulating fluidized bed and pretreat the flue gas to generate dust-laden gas with uniform flow rate and output it. In this embodiment of the invention, the flue gas pretreatment system is a flow field conditioning unit for high-temperature flue gas entering the dust removal front end. It is primarily responsible for the initial adjustment of the flue gas exiting the circulating fluidized bed to meet the flow field requirements of subsequent high-temperature electrostatic dust removal. Flue gas pretreatment includes, but is not limited to, large particle pre-separation, airflow distribution plate uniformization, and temperature and pressure stabilization control. Unlike existing technologies that add multiple stages of pretreatment equipment to conventional baghouse dust collectors, this invention achieves flue gas flow field uniformity without adding complex pretreatment equipment through physical structure optimizations such as large particle pre-separation and airflow distribution plate uniformization, thus avoiding the problem of frequent maintenance due to filter bag clogging.

[0026] The flue gas pretreatment system can effectively eliminate flue gas swirl, deviation, and excessively high local concentration, ensuring that the gas flow rate entering the high-temperature electrostatic precipitator is uniform and the particle distribution is relatively stable, thereby improving dust removal efficiency and reducing the risk of secondary dust generation.

[0027] The high-temperature electrostatic dust removal system 20 is connected to the flue gas pretreatment system and is used to remove dust from the dust-laden gas at high temperature, generate the first clean gas after dust removal and output it. In this embodiment of the invention, the high-temperature electrostatic precipitator system is a core dust removal device designed for medium-high temperature, high concentration, and oxygen-rich flue gas conditions. Maintaining the flue gas temperature at 350–750℃, the high-temperature electrostatic precipitator system uses a high-voltage electric field to charge particulate matter in the dust-laden gas and cause it to migrate towards the electrodes, ultimately achieving gas-solid separation. Compared to conventional electrostatic precipitators, its internal electrode materials and structural design are optimized for high-temperature and oxygen-rich environments, improving corrosion resistance and operational stability, while effectively capturing dust particles.

[0028] By placing high-temperature dust removal at the front end of the process, the traditional mode of forced cooling to adapt to the equipment has been changed, and the system can be operated safely and reliably under medium-high temperature and oxygen-rich conditions.

[0029] Waste heat recovery system 30 is connected to the high-temperature electrostatic dust removal system and is used to recover waste heat from the first clean gas to generate a cooled second clean gas and output it. In this embodiment of the invention, the waste heat recovery system is an energy cascade utilization unit used to recover the sensible heat from the clean flue gas after high-temperature dust removal. Since the flue gas temperature is still in the medium-high temperature range after dust removal, the system can convert the flue gas heat into usable energy sources such as preheated air, hot water production, or low-pressure steam through heat exchange methods such as gas-to-gas, gas-to-liquid, or gas-to-steam.

[0030] Compared with the multi-stage heat exchange and cooling system set before dust removal in the existing technology, the significant advantage of the embodiments of the present invention is that the clean flue gas after dust removal directly enters the heat exchanger, avoiding the problem of heat exchange surface contamination; the elimination of multiple stages of equipment such as air preheater and waste heat boiler achieves the goal of full resource utilization and improves energy utilization efficiency.

[0031] The dust collection system 40 is connected to the high-temperature electrostatic precipitator system and is used to collect the dust generated by the high-temperature electrostatic precipitator system.

[0032] In this embodiment of the invention, the dust collection system is a supporting material recovery unit for the high-temperature dust removal process, used to collect and transport the dust captured by the high-temperature electrostatic precipitator. The dust collection system mainly includes structures such as a dust hopper, a pneumatic conveying device, and a dust storage bin, which can ensure the continuous, stable discharge and closed transport of dust in a high-temperature environment.

[0033] The effective collection of dust by the dust collection system not only avoids the secondary accumulation of dust in the equipment, but also creates conditions for the subsequent resource utilization of dust, further improving the overall economy and environmental friendliness of the process system.

[0034] This invention employs a flue gas pretreatment system to pretreat the flue gas from a circulating fluidized bed, achieving a uniform distribution of flue gas velocity and thus improving the stability of subsequent treatment. A high-temperature electrostatic precipitator is connected to the flue gas pretreatment system via pipelines to perform high-temperature dust removal on the dust-laden gas, generating a first clean gas after dust removal and outputting it. This achieves high-efficiency dust removal without requiring an additional pre-cooling system, improving dust removal efficiency, reducing the cost of flue gas dust removal in the circulating fluidized bed, and improving upon the complex process of prior cooling followed by dust removal in existing technologies. It also achieves the improvement goal of a smaller footprint. Furthermore, this high-temperature electrostatic precipitator system is highly adaptable to compact sites. A waste heat recovery system is connected to the high-temperature electrostatic precipitator system via pipelines to recover waste heat from the first clean gas, generating a second clean gas after cooling and outputting it, thereby realizing the recovery and utilization of flue gas heat energy and reducing system energy consumption. A dust collection system is used to collect the dust generated by the high-temperature electrostatic precipitator system.

[0035] Figure 2 This is a process flow diagram of another flue gas treatment system provided in an embodiment of the present invention.

[0036] like Figure 2 As shown, the system may specifically include the following: The flue gas pretreatment system 10 is used to receive the flue gas from the circulating fluidized bed and pretreat the flue gas to generate dust-laden gas with uniform flow rate and output it. In this embodiment of the invention, the flue gas pretreatment system can be used to receive the flue gas output from the circulating fluidized bed in the preceding process. This flue gas is usually medium-high temperature oxygen-enriched flue gas, where medium-high temperature refers to 350-750℃ and oxygen-enriched refers to an oxygen concentration of 25%-35%.

[0037] In some embodiments, the flue gas pretreatment system 10 may include the following devices: A horizontal cyclone separator 101 is used to receive flue gas and perform cyclone dust removal treatment on the flue gas so that coarse particles in the flue gas are separated from the dust-laden gas. In this embodiment of the invention, the horizontal cyclone separator can adopt a large-diameter volute design with an inlet wind speed of 18-22 m / s. It is equipped with a guide plate and an ash hopper inside, and the bottom of the ash hopper is connected to a spiral ash discharge unit. The shell and guide plate are made of 316L stainless steel, and the inner wall is coated with a ceramic coating.

[0038] In some examples, a horizontal cyclone separator may include an inlet and an outlet; the inlet of the horizontal cyclone separator can be used to receive flue gas; and the outlet of the horizontal cyclone separator can be used to output dust-laden gas.

[0039] The horizontal cyclone separator removes more than 60% of the coarse particles from the flue gas in one go, reducing the dust load of the subsequent electrostatic precipitator and avoiding corona blockage. At the same time, the system resistance is reduced by optimizing the airflow direction.

[0040] The airflow distribution device 102 is connected to the horizontal cyclone separator through a pipeline. It is used to receive the dust-laden gas and to uniformly distribute the dust-laden gas to generate dust-laden gas with a uniform flow rate.

[0041] In this embodiment of the invention, the airflow distribution device can be located between the horizontal cyclone separator and the high-temperature electrostatic precipitator, and consists of a porous distribution plate and arc-shaped guide vanes, with a flow velocity sensor installed behind the distribution plate. The porous distribution plate can be made of 316L stainless steel, and the guide vanes are coated with a PTFE coating.

[0042] In some examples, the airflow equalization device may include an air inlet and an air outlet; the air inlet of the airflow equalization device may be connected to a horizontal cyclone separator via a pipe to receive dust-laden gas; the air outlet of the airflow equalization device may be connected to a high-temperature electrostatic precipitator system via a pipe to output dust-laden gas with a uniform flow rate.

[0043] By using an airflow distribution device, the deviation of the flue gas velocity entering the dust removal body can be controlled within ±5%, avoiding a decrease in dust removal efficiency caused by local high-speed airflow.

[0044] The high-temperature electrostatic dust removal system 20 is connected to the flue gas pretreatment system and is used to remove dust from the dust-laden gas at high temperature, generate the first clean gas after dust removal and output it. In this embodiment of the invention, the high-temperature electrostatic dust removal system 20 can be connected to the flue gas pretreatment system 10 through a pipeline for high-temperature dust removal of dust-laden gas, generating and outputting the first clean gas after dust removal.

[0045] In some embodiments, the high-temperature electrostatic dust removal system 20 may include the following devices: The first electric field generating device 201 is connected to the flue gas pretreatment system through a pipeline and is used to receive the dust-laden gas so that the dust particles in the dust-laden gas are charged and the charged dust-laden gas is output. In this embodiment of the invention, the first-stage electric field is a charged region. The cathode is made of tungsten wire, the anode is made of a flat 316L stainless steel plate, and the power supply voltage is 60-70kV.

[0046] In some examples, the first electric field generating device can generate the first electromechanical field. When a uniform airflow enters the first electric field, the central control system starts the high-voltage power supply and applies a 60-70kV DC voltage to the cathode tungsten filament. Corona discharge is generated in the electric field, which charges the dust particles in the flue gas.

[0047] In some examples, the first electric field generating device may include a first air inlet, a second air inlet, and an air outlet; the air inlet of the first electric field generating device may be connected to a flue gas pretreatment system via a pipe for receiving dust-laden gas; the air outlet of the first electric field generating device may be connected to the air inlet of the second electric field generating device via a pipe for outputting charged dust-laden gas; the second air inlet of the first electric field generating device is used to connect to the air outlet of a pulse valve for receiving compressed air output from the air inlet of the pulse valve to cause dust on the anode plate to fall off. The second electric field generating device 202 is connected to the first electric field generating device and is used to receive the charged dust-laden gas to capture dust particles in the charged dust-laden gas and output the first clean gas after dust removal. In this embodiment of the invention, the second electric field generating device can be designed with high field strength and low current density. By optimizing the electric field distribution on the surface of the dust collecting electrode, efficient collection of charged dust is achieved. The first and second electric field generating devices are housed in a single housing and are connected to each other.

[0048] In some examples, the second electric field generating device can generate a second-level electric field. Dust particles charged by the first-level electric field enter the second-level electric field with the airflow. The central control system switches to high-frequency pulse power supply. Under the action of electric field force, the charged dust particles move towards the honeycomb anode plate and are deposited. The collection efficiency of fine particles <5μm is over 96%, and the dust concentration in the purified flue gas is <8mg / Nm³.

[0049] In some examples, the second electric field generating device can also be equipped with a zoned power supply system, which can automatically adjust the electric field parameters of each zone according to changes in dust concentration to ensure the best dust removal effect.

[0050] For example, the second electric field generating device includes a first air inlet, a second air inlet, and an air outlet; the first air inlet of the second electric field generating device is connected to the air outlet of the first electric field generating device through a pipe, and is used to receive charged dust-laden gas; the air outlet of the second electric field generating device is connected to a waste heat recovery system through a pipe, and is used to output a first clean gas; the second air inlet of the second electric field generating device is used to connect to the air outlet of a pulse valve, and is used to receive compressed air output from the air inlet of the pulse valve to make the dust on the anode plate fall off.

[0051] In some embodiments, a first pressure sensor may be provided at the inlet front end of the first electric field generating device; and a second pressure sensor may be provided at the outlet rear end of the second electric field generating device. The preset dust removal conditions may include: the difference between the pressure value detected by the first pressure sensor and the pressure value detected by the second pressure sensor is greater than a preset pressure difference threshold.

[0052] In this embodiment of the invention, when the difference between the pressure value detected by the first pressure sensor and the pressure value detected by the second pressure sensor is greater than a preset pressure difference threshold, it is considered that the internal cavities of the first electric field generating device and the second electric field generating device are blocked by dust, and the dust removal condition is triggered.

[0053] Air compressor 203 is used to receive air and compress the air to generate compressed air; In this embodiment of the invention, the air compressor employs variable frequency control technology, which can automatically adjust the air output according to the system's dust removal requirements. The output pressure is stabilized within the range of 0.6-0.8 MPa, meeting the air pressure requirements for dust removal in high-temperature environments. An air drying and filtration system is included to ensure that the compressed air quality meets the requirements of the high-temperature dust removal system. In existing technologies, air compressors often operate at full load, resulting in high energy consumption. This device, through variable frequency regulation, can save energy and extend the equipment's service life.

[0054] In some examples, the air compressor may include an air inlet and an air outlet; the air inlet of the air compressor may be used to receive air; the air outlet of the air compressor may be connected to the air inlet of the dust removal controller via a pipe. By adjusting the air compressor, the waste of compressed air is avoided, the overall energy consumption is reduced, the failure rate of pulse valves and injection systems is reduced, and maintenance costs are lowered.

[0055] The dust removal controller 204 is connected to the air compressor and is used to receive the compressed air; In some examples, the dust removal controller may include an air inlet, a first air outlet, and a second air outlet; the air inlet of the dust removal controller may be connected to the air outlet of an air compressor via a pipe; the first air outlet of the dust removal controller may be connected to the air inlet of a plurality of pulse valves connected to a first electric field generating device via a pipe; and the second air outlet of the dust removal controller may be connected to the air inlet of a plurality of pulse valves connected to a second electric field generating device via a pipe. In this embodiment of the invention, the dust removal controller can adopt a PLC control system, which can intelligently decide the dust removal sequence and intensity based on preset dust removal conditions and real-time operating parameters. It can support multiple dust removal modes, including timed dust removal, resistance-based dust removal, and manual dust removal, to meet the needs of different working conditions. The controller has a self-diagnostic function and can monitor the operating status of the dust removal system in real time.

[0056] In some examples, when the difference between the pressure value detected by the first pressure sensor and the pressure value detected by the second pressure sensor is greater than the preset pressure difference threshold, the high-voltage power supply of the first-stage electric field is first turned off, the corresponding pulse valve is opened, and 0.7MPa compressed air is injected into the anode plate to shake the dust into the ash hopper; after an interval of 10 minutes, the same dust removal operation is performed on the second-stage electric field. During the dust removal process, the flue gas flows normally and does not affect the continuous operation of the system.

[0057] Compared to traditional timed dust removal methods, this device offers more precise intelligent dust removal control. It also solves the problem of insufficient or excessive dust removal often caused by fixed-cycle dust removal in existing technologies, thus improving dust removal efficiency. Precise dust removal control avoids secondary dust generation caused by over-cleaning, resulting in more stable dust removal efficiency.

[0058] A plurality of pulse valves 205 are provided, each of which is connected to the dust removal controller and the anode plate of the first electric field generating device or the anode plate of the second electric field generating device. When the preset dust removal conditions are met, the pulse valve receives the compressed air output by the dust removal controller and opens the gas valve to spray the compressed air onto the anode plate of the first electric field generating device or the anode plate of the second electric field generating device, so that the dust adhering to the anode plate of the first electric field generating device or the anode plate of the second electric field generating device falls off.

[0059] In this embodiment of the invention, the pulse valve can adopt a large-diameter, fast-response design with an opening time of less than 50ms. The valve body is made of high-temperature resistant material and can operate stably for a long time in environments above 350℃. Compared with traditional pulse valves, the fast-response characteristics of this embodiment make dust removal more efficient and significantly improve reliability under high-temperature conditions.

[0060] In some examples, a plurality of pulse valves may include an air inlet and an air outlet; the air inlet of each pulse valve connected to the first electric field generating device may be connected to the first air outlet of the dust removal controller via a pipe, and may be used to receive compressed air output by the dust removal controller; the air inlet of each pulse valve connected to the second electric field generating device may be connected to the air outlet of the dust removal controller via a pipe, and may be used to receive the compressed air output by the dust removal controller; the air outlet of each pulse valve may be connected to the air inlet on the anode plate of the first electric field generating device or the anode plate of the second electric field generating device via a pipe, and may be used to output the compressed air to the anode plate; Waste heat recovery system 30 is connected to the high-temperature electrostatic dust removal system and is used to recover waste heat from the first clean gas to generate a cooled second clean gas and output it. In some embodiments, the waste heat recovery system 30 may include the following devices: The explosion-proof control device 301 is used to receive the first clean gas output by the high-temperature electrostatic dust removal system, detect the oxygen content in the first clean gas, and output the first clean gas when the oxygen content is greater than a preset oxygen content threshold. In this embodiment of the invention, the explosion-proof control device operates in real time, and the oxygen content monitor collects data once per second. If the oxygen content of the clean gas at the inlet is >35%, the explosion-proof control device immediately triggers the nitrogen injection module, opens the nitrogen injection valve, and injects nitrogen into the dust removal body inlet. If the spark detector detects a spark in the electric field, it immediately cuts off the high-voltage power supply, injects nitrogen, and opens the pressure relief valve. Operation resumes after the risk is eliminated.

[0061] Optionally, the explosion-proof control device may include an air inlet and an air outlet; the air inlet of the explosion-proof control device is connected to a high-temperature electrostatic dust removal system via a pipe for receiving the first clean gas; the air outlet of the explosion-proof control device is connected to the first air inlet of the heat exchanger via a pipe for outputting the first clean gas. In some examples, the explosion-proof control device may include the following modules: Oxygen content monitor 3011 is used to detect the oxygen content in the first clean gas; In this embodiment of the invention, the oxygen content monitor can employ a high-temperature oxygen sensor based on the zirconium oxide principle, which can continuously monitor oxygen concentration directly in a flue gas environment of 350-550℃. This monitor features fast response time and high accuracy.

[0062] The dustproof and corrosion-resistant design ensures long-term stable operation in dusty conditions, and the monitoring data can be transmitted to the control system in real time, providing basic data support for safe operation.

[0063] An outlet is used to output the first clean gas to the heat exchanger; In this embodiment of the invention, the air outlet can be made of high-temperature stainless steel and has a multi-layer sealing structure to ensure reliable sealing under high temperature and high pressure. The air outlet design takes into account the uniformity of the flow field and adopts a gradually expanding structure to reduce the flow velocity and reduce pressure loss.

[0064] The nitrogen injection module 3012 turns on and closes the outlet when the oxygen content is greater than a preset oxygen content threshold.

[0065] In this embodiment of the invention, the nitrogen injection module may include components such as a nitrogen storage tank, a pressure reducing valve, and a quick-shut-off valve. For example, when the oxygen content monitor detects that the oxygen concentration exceeds the safety threshold of 8%, the control system automatically closes the gas outlet and simultaneously activates the nitrogen injection module. Nitrogen is injected into the system at a specific flow rate to rapidly dilute the oxygen concentration in the flue gas and prevent the risk of explosion. The module has both manual and automatic control modes to ensure safe operation under various working conditions.

[0066] Heat exchanger 302 is connected to the explosion-proof control device via a pipeline and is used to receive air and the first clean gas output by the explosion-proof control device, so that the air and the first clean gas exchange heat and generate the cooled second clean gas.

[0067] In this embodiment of the invention, the heat exchanger can be designed as a shell-and-tube heat exchanger to achieve efficient heat exchange. The flue gas side uses high-temperature corrosion-resistant materials to ensure long-term stable operation at temperatures of 350-550℃. The heat exchanger design fully considers thermal expansion, incorporating reasonable expansion joints and support structures to prevent equipment damage caused by temperature changes.

[0068] For example, the heat exchanger 302 may include a first air inlet, a second air inlet, and an air outlet; the first air inlet of the heat exchanger is connected to the air outlet of the explosion-proof control device through a pipe for receiving a first clean gas; the second air inlet of the heat exchanger is used to receive air; and the air outlet of the heat exchanger is used to output the first clean gas.

[0069] In some examples, the first clean gas can enter the waste heat recovery unit and exchange heat with the ambient temperature combustion air in the shell side through a shell-and-tube heat exchanger. The air is heated to 250-300°C and then sent to the gasifier. The temperature of the first clean gas drops to 200-250°C and then enters the subsequent desulfurization process.

[0070] The dust collection system 40 is connected to the high-temperature electrostatic precipitator system and is used to collect the dust generated by the high-temperature electrostatic precipitator system.

[0071] In this embodiment of the invention, the dust collection system can be connected to a high-temperature electrostatic precipitator system to collect the dust generated by the high-temperature electrostatic precipitator system.

[0072] In some embodiments, the dust collection system 40 may include the following devices: The horizontal screw conveyor 401 is connected to the high-temperature electrostatic precipitator system via a pipeline and is used to receive dust from the high-temperature electrostatic precipitator system. In this embodiment of the invention, the high-temperature electrostatic dust removal system may include a dust hopper. The dust in the dust hopper is continuously conveyed by a spiral dust discharge unit and discharged into the dust bin through a star-shaped unloading valve. The unloading valve is linked to the spiral conveyor to ensure that the hourly dust discharge amount matches the dust collection amount.

[0073] Ash silo 402 is connected to the horizontal screw conveyor via a pipe and is used to receive and store the dust output by the horizontal screw conveyor.

[0074] In this embodiment of the invention, the ash silo can adopt a double-layer structure design, with an inner layer of wear-resistant and high-temperature resistant alloy lining and an outer layer of thermal insulation, which can stably store dust in a long-term high-temperature environment of 300-400℃, effectively maintaining the activity of the dust. An explosion relief valve and a level gauge can be installed on the top of the ash silo. The explosion relief valve can automatically open when the internal pressure rises abnormally, ensuring equipment safety; the level gauge monitors the amount of powder stored in real time, realizing automated management. Furthermore, the ash silo discharge port is equipped with a double-layer ash discharge valve, which ensures airtightness, prevents air leakage and dust escape, and achieves an airtight connection between the ash silo and the subsequent conveying system, meeting environmental protection requirements and creating favorable conditions for the subsequent resource recycling and utilization of dust.

[0075] This invention addresses the problem of complex pretreatment systems required by traditional processes to accommodate baghouse dust collectors by employing a combined pretreatment method of a horizontal cyclone separator and an airflow distribution device. Through an integrated intelligent dust removal control system with high-temperature electrostatic precipitator, it achieves efficient dust removal of medium- and high-temperature dust-laden flue gas from circulating fluidized beds, avoiding the problems of high system resistance, high energy consumption, and drastically increased investment costs caused by the need for redundant forced cooling devices due to the insufficient temperature resistance of conventional baghouse dust collectors. A waste heat recovery system combining explosion-proof control devices and high-efficiency heat exchangers ensures efficient heat recovery while maintaining safety. A high-temperature, closed-loop dust collection system preserves dust activity for resource utilization. This invention overcomes the technical bottlenecks of traditional processes under high-temperature, high-concentration, and oxygen-rich conditions, simplifying the flue gas purification and waste heat recovery system, improving energy efficiency, and ensuring safe and reliable operation.

[0076] In the description of this invention, it should be understood that the terms "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are used only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0077] Furthermore, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0078] Although preferred embodiments of the present invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the embodiments of the present invention.

[0079] Finally, it should be noted that in this document, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. Relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or terminal device. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or terminal device that includes said element.

[0080] The flue gas treatment system provided by the present invention has been described in detail above. Specific examples have been used to illustrate the principle and implementation of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A flue gas treatment system, characterized in that, The system comprises: a flue gas pretreatment system for receiving flue gas of a circulating fluidized bed and pretreating the flue gas to generate dust-containing gas with uniform flow rate and output; a high-temperature electrostatic precipitation system connected with the flue gas pretreatment system for high-temperature dust removal of the dust-containing gas to generate first clean gas after dust removal and output; a waste heat recovery system connected with the high-temperature electrostatic precipitation system for waste heat recovery treatment of the first clean gas to generate second clean gas after temperature reduction and output; a dust collection system connected with the high-temperature electrostatic precipitation system for collecting dust generated by the high-temperature electrostatic precipitation system.

2. The flue gas treatment system of claim 1, wherein, The flue gas pretreatment system comprises: a horizontal cyclone separator for receiving flue gas and performing cyclone dust removal treatment on the flue gas to separate coarse particles in the flue gas from the dust-containing gas; a gas flow uniform distribution device connected with the horizontal cyclone separator through a pipeline for receiving the dust-containing gas and performing uniform distribution treatment on the dust-containing gas to generate dust-containing gas with uniform flow rate.

3. The flue gas treatment system of claim 1, wherein, The high-temperature electrostatic precipitation system comprises: a first electric field generating device connected with the flue gas pretreatment system through a pipeline for receiving the dust-containing gas to make dust particles in the dust-containing gas carry electric charges and output charged dust-containing gas; a second electric field generating device in communication with the first electric field generating device for receiving the charged dust-containing gas to capture dust particles in the charged dust-containing gas and output first clean gas after dust removal; an air compressor for receiving air and compressing the air to generate compressed air; a soot blowing controller connected with the air compressor for receiving the compressed air; a plurality of pulse valves, each of which is connected with the soot blowing controller and an anode plate of the first electric field generating device or an anode plate of the second electric field generating device, and when a preset soot blowing condition is met, receives the compressed air output by the soot blowing controller and opens a gas valve to spray the compressed air onto the anode plate of the first electric field generating device or the anode plate of the second electric field generating device to make dust attached to the anode plate of the first electric field generating device or the anode plate of the second electric field generating device fall off.

4. The flue gas treatment system of claim 3, wherein, A first pressure sensor is arranged at the front end of the inlet of the first electric field generating device, and a second pressure sensor is arranged at the rear end of the outlet of the second electric field generating device. The preset soot blowing condition comprises that the difference between the pressure value detected by the first pressure sensor and the pressure value detected by the second pressure sensor is greater than a preset pressure difference threshold.

5. The flue gas treatment system of claim 1, wherein, The waste heat recovery system comprises: an explosion-proof control device for receiving the first clean gas output by the high-temperature electrostatic precipitation system and detecting the oxygen content in the first clean gas, and when the oxygen content is greater than a preset oxygen content threshold, outputting the first clean gas; a heat exchanger connected with the explosion-proof control device through a pipeline for receiving air and the first clean gas output by the explosion-proof control device to exchange heat between the air and the first clean gas and generate the second clean gas after temperature reduction.

6. The flue gas treatment system of claim 5, wherein, The explosion-proof control device comprises: an oxygen content monitor for detecting the oxygen content in the first clean gas; an outlet for outputting the first clean gas to the heat exchanger; a nitrogen injection module, when the oxygen content is greater than a preset oxygen content threshold, the nitrogen injection module is opened and the outlet is closed.

7. The flue gas treatment system of claim 1, wherein, The dust collection system comprises: a horizontal screw conveyor connected to the high-temperature electrostatic dust removal system through a pipeline for receiving the dust in the high-temperature electrostatic dust removal system; a dust bin connected to the horizontal screw conveyor through a pipeline for receiving and storing the dust output by the horizontal screw conveyor.

8. The flue gas treatment system according to claim 2, wherein the horizontal cyclone separator comprises an inlet and an outlet; the inlet of the horizontal cyclone separator is used for receiving the flue gas; and the outlet of the horizontal cyclone separator is used for outputting the dust-containing gas; the airflow uniformizing device comprises an inlet and an outlet; the inlet of the airflow uniformizing device is connected to the horizontal cyclone separator through a pipeline for receiving the dust-containing gas; and the outlet of the airflow uniformizing device is connected to the high-temperature electrostatic dust removal system through a pipeline for outputting the dust-containing gas with uniform flow rate.

9. The flue gas treatment system according to claim 3, wherein the air compressor comprises an inlet and an outlet; the inlet of the air compressor is used for receiving air; and the outlet of the air compressor is connected to the inlet of the soot control device through a pipeline; the soot control device comprises an inlet, a first outlet and a second outlet; the inlet of the soot control device is connected to the outlet of the air compressor through a pipeline; the first outlet of the soot control device is connected to the inlets of a plurality of pulse valves connected to the first electric field generating device through a pipeline; and the second outlet of the soot control device is connected to the inlets of a plurality of pulse valves connected to the second electric field generating device through a pipeline; the plurality of pulse valves comprise an inlet and an outlet; the inlet of each pulse valve connected to the first electric field generating device is connected to the first outlet of the soot control device through a pipeline for receiving the compressed air output by the soot control device; the inlet of each pulse valve connected to the second electric field generating device is connected to the second outlet of the soot control device through a pipeline for receiving the compressed air output by the soot control device; and the outlet of each pulse valve is connected to the inlets on the anode plates of the first electric field generating device or the second electric field generating device through a pipeline for outputting the compressed air to the anode plates. The first electric field generating device comprises a first air inlet, a second air inlet and an air outlet; the air inlets of the first electric field generating device are connected with the flue gas pretreatment system through pipelines for receiving the dust-containing gas; the air outlet of the first electric field generating device is connected with the air inlet of the second electric field generating device through a pipeline for outputting the charged dust-containing gas; the second air inlet of the first electric field generating device is connected with the air outlet of the pulse valve for receiving the compressed air output by the air inlet of the pulse valve to make the dust on the anode plate fall off; The second electric field generating device comprises a first air inlet, a second air inlet and an air outlet; the first air inlet of the second electric field generating device is connected with the air outlet of the first electric field generating device through a pipeline for receiving the charged dust-containing gas; the air outlet of the second electric field generating device is connected with the waste heat recovery system through a pipeline for outputting the first clean gas; the second air inlet of the second electric field generating device is connected with the air outlet of the pulse valve for receiving the compressed air output by the air inlet of the pulse valve to make the dust on the anode plate fall off.

10. The flue gas treatment system according to claim 5, characterized in that, The explosion-proof control device comprises an air inlet and an air outlet; the air inlet of the explosion-proof control device is connected with the high-temperature electrostatic precipitation system through a pipeline for receiving the first clean gas; the air outlet of the explosion-proof control device is connected with the first air inlet of the heat exchanger through a pipeline for outputting the first clean gas; The heat exchanger comprises a first air inlet, a second air inlet and an air outlet; the first air inlet of the heat exchanger is connected with the air outlet of the explosion-proof control device through a pipeline for receiving the first clean gas; the second air inlet of the heat exchanger is used for receiving air; the air outlet of the heat exchanger is used for outputting the first clean gas.

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