An integrated desulfurization and denitrification waste heat recovery device based on red mud particles
By using a fluidized bed reactor with red mud particles as a catalyst and a multi-stage separator design, the economic and safety issues of integrated flue gas desulfurization and denitrification were solved, achieving low-temperature denitrification and solid waste resource utilization, and reducing the cost and complexity of flue gas purification.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- BEIJING SPC ENVIRONMENT PROTECTION TECH
- Filing Date
- 2025-07-31
- Publication Date
- 2026-07-03
AI Technical Summary
Existing technologies are insufficient to achieve economical, stable, and universally applicable integrated flue gas desulfurization and denitrification. Furthermore, traditional denitrification processes require the consumption of ammonia, posing safety risks and requiring high temperatures.
Red mud particles are used as a catalytic absorbent. Through the design of a fluidized bed reactor and a multi-stage separator, the simultaneous absorption of sulfur dioxide and nitrogen oxides in flue gas is achieved. The porous structure and high alkalinity of red mud are utilized, combined with a humidity-regulating heat exchanger to recover heat from the flue gas, reduce the reaction temperature, and achieve desulfurization and denitrification.
It achieves low-temperature denitrification without consuming ammonia, reduces construction and operation costs, realizes efficient purification of flue gas and resource utilization of solid waste, simplifies the process flow, and reduces environmental risks.
Smart Images
Figure CN224442652U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the technical field of flue gas treatment equipment, and in particular to an integrated device for desulfurization, denitrification and waste heat recovery based on red mud particles. Background Technology
[0002] With the accelerating pace of industrialization, the use of coal-fired boilers is becoming increasingly frequent, but the resulting environmental pollution problems are also becoming more and more serious. These include nitrogen oxides, sulfur dioxide, and exhaust gases, which severely pollute the atmospheric environment and may contribute to acid rain formation. Currently, many thermal power plants in China employ flue gas desulfurization technology during coal-fired power generation, with the limestone-gypsum method being widely used. In addition, some thermal power plants combine this with other flue gas treatment methods, such as rotary spray semi-dry desulfurization, seawater desulfurization, and circulating fluidized bed desulfurization, to further improve desulfurization efficiency.
[0003] With the continuous development of my country's economy and the scale of thermal power plants, people's environmental awareness has gradually increased, and the requirements for desulfurization and denitrification technologies have also risen. Therefore, Chinese researchers are committed to integrating desulfurization and denitrification technologies to achieve integrated development, thereby further reducing the degree of flue gas pollution from thermal power plants.
[0004] Simultaneous flue gas desulfurization and denitrification technologies are mostly in the research and industrial demonstration stage. However, because they can achieve desulfurization and denitrification simultaneously in a single system, and especially with the increasingly stringent NOx control standards, these technologies are receiving increasing attention from various countries. There are three main types of simultaneous flue gas desulfurization and denitrification technologies: the first is a combination of flue gas desulfurization and denitrification technologies; the second utilizes adsorbents to simultaneously remove SO2 and NOx; and the third involves modifying existing flue gas desulfurization (FGD) systems (such as adding denitrification agents to the desulfurization liquid) to add denitrification functionality.
[0005] While the concentrations of SO2 and NOx in flue gas from thermal power plant boilers are not high, their total amount is substantial. Using two separate systems for desulfurization and denitrification would not only require a large land area but also incur high investment, management, and operating costs. In recent years, countries worldwide have successively conducted research and development on simultaneous desulfurization and denitrification technologies and implemented them to some extent in industrial applications. Among SO2 / NOx combined removal technologies, some employ a combination of flue gas desulfurization and denitrification, while others utilize adsorbents to simultaneously remove SO2 and NOx. All of these technologies can achieve high removal efficiencies; however, due to limitations in specific industrial application conditions and requirements, none of these integrated technologies have yet achieved widespread application and promotion.
[0006] Therefore, there is an urgent need to find an integrated desulfurization and denitrification technology that is economical, stable, and versatile, to meet the current innovation needs of the environmental protection field in the process of industrialization. Utility Model Content
[0007] In view of the technical problems existing in the background art, this utility model patent provides an integrated desulfurization and denitrification waste heat recovery device based on red mud particles. It fully recovers the heat in the flue gas by using a humidity heat exchanger. When the flue gas temperature drops to the reaction range, the flue gas desulfurization and denitrification are completed simultaneously by using a fluidized bed reactor. It has a simple structure and low cost.
[0008] To achieve the above objectives, this utility model provides an integrated desulfurization and denitrification waste heat recovery device based on red mud particles, including a fluidized bed reactor. The bottom flue gas inlet of the fluidized bed reactor is provided with a Venturi nozzle, and the lower end of the Venturi nozzle is connected to a humidity conditioning heat exchanger. The bottom of the humidity conditioning heat exchanger is provided with a flue gas inlet.
[0009] The fluidized bed reactor is filled with granular red mud. Its upper and lower parts are connected to the upper and lower parts of the cyclone separator via pipes. The top of the cyclone separator is connected to one end of a bag filter via a pipe. The other end of the bag filter is provided with a flue gas outlet.
[0010] As a further improvement of this utility model, the humidity-regulating heat exchanger is provided with a heat exchange coil.
[0011] As a further improvement of this utility model, a humidifying spray pipe is provided below the heat exchange coil.
[0012] As a further improvement of this utility model, the connecting pipe between the lower part of the fluidized bed reactor and the lower part of the cyclone separator is inclined, and one end of the cyclone separator is higher than one end of the fluidized bed reactor.
[0013] As a further improvement of this utility model, the bottom of the cyclone separator is also provided with a red mud unloading pipe.
[0014] As a further improvement of this utility model, a belt conveyor is provided below the red mud unloading pipe.
[0015] As a further improvement of this utility model, a dust collection hopper is provided below the bag filter.
[0016] As a further improvement of this utility model, the particle size of the granular red mud filled in the fluidized bed reactor is 1~8mm.
[0017] As a further improvement of this utility model, the humidity-regulating heat exchanger is equipped with a flue gas moisture content monitoring instrument.
[0018] Compared with the prior art, the beneficial effects of this utility model are as follows:
[0019] This invention utilizes red mud particles as a catalytic absorbent to simultaneously complete the desulfurization and denitrification processes. During this process, the highly alkaline waste red mud generated from alumina production is also utilized as a resource. The desulfurization and denitrification process of this invention does not require ammonia and operates at a low reaction temperature. Therefore, heat recovery from the flue gas is achieved through a humidity-regulating heat exchanger before desulfurization and denitrification. Furthermore, this device can perform multi-stage collection of particulate matter during the desulfurization process, including red mud particles, a cyclone separator, and a bag filter, thus purifying the particulate matter in the flue gas. Attached Figure Description
[0020] Figure 1 This is a schematic diagram of an integrated desulfurization and denitrification waste heat recovery device based on red mud particles, as disclosed in one embodiment of this utility model.
[0021] Explanation of reference numerals in the attached figures:
[0022] 1. Fluidized bed reactor; 2. Humidity conditioning heat exchanger; 3. Cyclone separator; 4. Bag filter; 5. Flue gas inlet; 6. Venturi nozzle; 7. Flue A; 8. Red mud return pipe; 9. Heat exchange coil; 10. Humidifying spray pipe; 11. Flue B; 12. Red mud discharge pipe; 13. Belt conveyor; 14. Dust collector hopper; 15. Flue gas outlet. Detailed Implementation
[0023] It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.
[0024] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this utility model 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 this utility model. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.
[0025] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.
[0026] The present invention will now be described in further detail with reference to the accompanying drawings:
[0027] like Figure 1 As shown, the present invention provides an integrated desulfurization and denitrification waste heat recovery device based on red mud particles, including a fluidized bed reactor 1, a venturi nozzle 6 at the bottom flue gas inlet 5 of the fluidized bed reactor 1, a humidity conditioning heat exchanger 2 connected to the lower end of the venturi nozzle 6, and a flue gas inlet 5 at the bottom of the humidity conditioning heat exchanger 2.
[0028] The fluidized bed reactor 1 is filled with granular red mud. Its upper and lower parts are connected to the upper and lower parts of the cyclone separator 3 via pipes. The pipe between the upper part of the fluidized bed reactor 1 and the upper part of the cyclone separator 3 serves as flue A7. The top of the cyclone separator 3 is connected to one end of the bag filter 4 via a pipe, which serves as flue B11. The other end of the bag filter 4 is provided with a flue gas outlet 15.
[0029] High-temperature flue gas enters the humidity-regulating heat exchanger 2 through the flue gas inlet 5 below it. The temperature of the flue gas is adjusted by the humidity-regulating heat exchanger 2 to reach a suitable reaction range, and the temperature is reduced to 70°C to 110°C by absorbing residual heat. After temperature adjustment, the flue gas overflows from the top of the humidity-regulating heat exchanger 2, is accelerated by the Venturi nozzle 6, and then enters the fluidized bed reactor 1. The accelerated flue gas fully agitates the red mud particles in the fluidized bed reactor 1, creating a fluidization effect. In the fluidized bed reactor 1, sulfur dioxide and nitrogen oxides in the flue gas are fully absorbed, intercepted, and purified. The reaction products adhere to the red mud particles, and most of the particulate matter in the flue gas is also intercepted during the fluidization collision with the particulate red mud, mixing into the red mud particles.
[0030] After the flue gas has reacted in the fluidized bed reactor 1, it overflows from the upper pipe of the fluidized bed reactor 1 to the cyclone separator 3. At the same time, the red mud particles and dust carried in the flue gas are also carried into the cyclone separator 3. Under the combined action of centrifugal force, gravity and inertial force in the cyclone separator 3, the flue gas containing only a small amount of particulate matter is discharged through the pipe at the top of the cyclone separator 3 to the bag filter 4. The particulate red mud and dust in the flue gas are deposited at the bottom of the cyclone separator 3. Some of the mixed particles are transported back to the fluidized bed reactor 1 through the connecting pipe between the lower part of the fluidized bed reactor 1 and the lower part of the cyclone separator 3.
[0031] The flue gas discharged from the cyclone separator 3 to the bag filter 4 still contains a small amount of dust. After the dust in the flue gas is intercepted by the bag filter 4, it is discharged to the chimney through the flue gas outlet 15 of the bag filter 4.
[0032] In this utility model, the humidity-regulating heat exchanger 2 is equipped with a heat exchange coil 9, which absorbs the waste heat of the flue gas and reduces the flue gas temperature to 70°C to 110°C.
[0033] In this utility model, a humidifying spray pipe 10 is provided in the lower part of the temperature-regulating heat exchange plate (below the heat exchange plate tube 9). By adjusting the operation of the humidifying spray pipe 10, the humidity of the flue gas can be adjusted to reach a suitable reaction range. Furthermore, a flue gas moisture content monitoring instrument is provided in the humidity-regulating heat exchanger 2. The operation of the humidifying spray pipe 10 is adjusted by monitoring the flue gas moisture content.
[0034] In this invention, the connecting pipe between the lower part of the fluidized bed reactor 1 and the lower part of the cyclone separator 3 is inclined, serving as the red mud return pipe 8. One end of the red mud return pipe 8 in the cyclone separator 3 is higher than the other end in the fluidized bed reactor 1. Red mud particles and dust entering the cyclone separator 3 are subjected to the combined effects of centrifugal force, gravity, and inertia of the cyclone separator 3, causing the particulate red mud and dust to deposit at the bottom of the cyclone separator 3. Figure 1 As shown, the bottom of the cyclone separator 3 is funnel-shaped, which facilitates the collection of red mud particles and dust. Some of the mixed particles of red mud and dust are transported back to the fluidized bed reactor 1 through the red mud return pipe 8.
[0035] In this invention, the bottom of the cyclone separator 3 is also equipped with a red mud discharge pipe 12. The remaining red mud particles and dust particles mixed in the cyclone separator 3 are sent out of the system through the red mud discharge pipe 12. Furthermore, a belt conveyor 13 is provided below the red mud discharge pipe 12, and the discharge from the red mud discharge pipe 12 is sent to the red mud regeneration system or solidification treatment system via the belt conveyor. Even further, since the red mud particles are larger than the dust particles, the discharge from the red mud discharge pipe 12 can be separated into red mud particles and dust particles through simple sieving and filtration.
[0036] In this invention, the ratio of red mud return pipe 8 to red mud discharge pipe 12 is adjusted by monitoring conditions such as the amount of material in the fluidized bed reactor 1 and the desulfurization and denitrification reaction efficiency.
[0037] In this invention, the flue gas containing a small amount of dust discharged from the cyclone separator 3 is conveyed to the bag filter 4 through flue B11. The bag filter 4 adopts a conventional design, with a dust hopper at its bottom. Since a large amount of dust in the flue gas has already been intercepted and separated by the upstream process, the bag filter 4 can be simplified to reduce construction costs. The remaining particulate matter in the flue gas, after being intercepted by the bag filter 4, is discharged from the system through the dust hopper 14. Finally, the purified flue gas is discharged to the chimney through the flue gas outlet 15.
[0038] The granular red mud filled in the fluidized bed reactor 1 of this invention has a particle size of 1~8mm. Example
[0039] This device performs desulfurization, denitrification, and waste heat recovery on high-temperature (≥100℃) flue gas (containing sulfur, nitrogen oxides, and dust) from industrial boilers (coal-fired boilers / gas-fired boilers / steel sintering / pelletizing / cement kilns / glass kilns, etc.). The fluidized bed reactor 1 is pre-filled with a certain amount of 6mm diameter red mud particles. The process includes:
[0040] S1. Flue gas enters the humidity heat exchanger 2 through flue gas inlet 5;
[0041] S2. In the humidification heat exchanger 2, the moisture content of the flue gas is monitored by instruments, and the operation of the humidification spray pipe 10 is adjusted to regulate the humidity of the flue gas to reach a suitable reaction range.
[0042] S3. After humidification, the flue gas passes through heat exchange coil 9 for heat exchange, fully absorbing the waste heat of the flue gas and reducing the flue gas temperature to 70℃ to 110℃.
[0043] S4. The flue gas, after heat exchange and cooling, is accelerated through the Venturi nozzle 6 and enters the fluidized bed reactor 1. The accelerated flue gas fully agitates the red mud particles in the fluidized bed reactor 1, creating a fluidization effect. In the fluidized bed reactor 1, sulfur dioxide and nitrogen oxides in the flue gas are fully absorbed, intercepted, and purified. The reaction products adhere to the red mud particles, and most of the particulate matter in the flue gas is intercepted during the fluidization collision with the red mud and mixed into the red mud particles.
[0044] S5. The flue gas after the fluidized bed reaction is conveyed to the cyclone separator 3 through flue A7. At the same time, the red mud particles and dust carried in the flue gas are also brought into the cyclone separator 3. Under the combined action of centrifugal force, gravity and inertial force in the cyclone separator 3, the flue gas containing only a small amount of particulate matter is discharged from the cyclone separator 3, and the particulate red mud and dust in the flue gas are deposited at the bottom of the cyclone separator 3.
[0045] S5. Some of the mixed particles deposited at the bottom of the cyclone separator 3 are transported back to the fluidized bed reactor 1 through the red mud return pipe 8. The other mixed particles are discharged through the red mud discharge pipe 12 to the belt conveyor 13 below. The belt conveyor 13 sends the mixed particles to the red mud regeneration system or the solidification treatment system.
[0046] S7. The flue gas containing a small amount of dust discharged from the cyclone separator 3 is transported to the bag filter 4 through the flue B11. The remaining particulate matter in the flue gas is intercepted by the bag filter 4 and discharged from the system through the dust collector hopper 14.
[0047] S8. The purified flue gas is discharged to the chimney through flue gas outlet 15.
[0048] Advantages of this utility model:
[0049] This invention utilizes red mud particles as a catalytic absorbent to simultaneously complete the desulfurization and denitrification processes. Red mud, a highly alkaline waste residue generated during alumina production, can be directly used for desulfurization and denitrification, achieving resource utilization of solid waste and reducing the environmental risks associated with stockpiling. The porous structure, large specific surface area, and high alkalinity of red mud endow it with excellent adsorption capacity and reactivity, promoting the capture and neutralization of gaseous pollutants. The system design utilizing red mud particles for simultaneous desulfurization and denitrification effectively reduces the complexity of traditional stationary source flue gas pollution reduction processes, lowers the complexity of environmental protection facilities, reduces construction and operating costs, and simultaneously achieves resource utilization of red mud as solid waste.
[0050] This invention achieves low-temperature denitrification without consuming ammonia. Conventional flue gas denitrification systems often employ processes such as SCR (Selective Catalytic Reduction), SNCR (Selective Non-Catalytic Reduction), or activated coke / activated carbon dry adsorption. These processes share the common characteristics of requiring high reaction temperatures and consuming ammonia as a reducing agent. While SCR has the lowest temperature requirement, even conventional SCR processes still require temperatures above 180°C. Regarding ammonia consumption, existing flue gas denitrification processes all require ammonia or urea, which inherently poses safety and escape risks. This device utilizes a red mud-based catalyst that can achieve desulfurization and denitrification reactions on its own, without consuming other substances. Furthermore, the reaction temperature is as low as 70 to 90°C, providing significant potential for flue gas heat recovery.
[0051] The multi-stage design of this utility model device enables multi-stage capture of particulate matter in flue gas during desulfurization and denitrification processes. Firstly, when the flue gas enters the fluidized bed reactor, most of the particulate matter is intercepted by the red mud catalyst within the reactor and mixed into the catalyst. The mixed flue gas, after primary dust removal, enters the cyclone separator from the fluidized bed reactor. During this process, the cyclone separator also intercepts a large amount of dust mixed with the red mud catalyst particles. This dust, along with the red mud particles, leaves the device through the red mud discharge pipe. The mixed particles after leaving the device undergo simple sieving to separate the red mud catalyst particles from the dust particles (red mud particles have a diameter of 1 to 8 mm, much larger than dust particles). The remaining particulate matter that has not been fully removed finally enters a bag filter for third-stage removal, ultimately achieving synergistic purification of the flue gas particulate matter.
[0052] The above are merely preferred embodiments of this utility model and do not limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.
Claims
1. A red mud particle-based desulfurization and denitrification waste heat recovery integrated device, characterized by: The fluidized bed reactor includes a venturi nozzle at the bottom flue gas inlet of the fluidized bed reactor, the lower end of the venturi nozzle is connected to a humidity conditioning heat exchanger, and the bottom of the humidity conditioning heat exchanger is provided with a flue gas inlet. The fluidized bed reactor is filled with granular red mud. Its upper and lower parts are connected to the upper and lower parts of the cyclone separator via pipes. The top of the cyclone separator is connected to one end of a bag filter via a pipe. The other end of the bag filter is provided with a flue gas outlet.
2. The red mud particle-based desulfurization and denitrification waste heat recovery integrated device according to claim 1, characterized in that: The humidity-regulating heat exchanger is equipped with a heat exchange coil.
3. The red mud particle-based desulfurization and denitrification waste heat recovery integrated device according to claim 2, characterized in that: A humidifying spray pipe is provided below the heat exchange coil.
4. The red mud particle-based desulfurization and denitrification waste heat recovery integrated device according to claim 1, characterized in that: The connecting pipe between the lower part of the fluidized bed reactor and the lower part of the cyclone separator is inclined, and one end of the cyclone separator is higher than one end of the fluidized bed reactor.
5. The red mud particle-based desulfurization and denitrification waste heat recovery integrated device according to claim 1, characterized in that: The bottom of the cyclone separator is also equipped with a red mud unloading pipe.
6. The red mud particle-based desulfurization and denitrification waste heat recovery integrated device according to claim 5, characterized in that: A belt conveyor is installed below the red mud unloading pipe.
7. The red mud particle-based desulfurization and denitrification waste heat recovery integrated device according to claim 1, characterized in that: The bag filter is equipped with a dust hopper at the bottom.
8. The red mud particle-based desulfurization and denitrification waste heat recovery integrated device according to claim 1, characterized in that: The granular red mud packed in the fluidized bed reactor has a particle size of 1~8mm.
9. The integrated desulfurization and denitrification waste heat recovery device based on red mud particles according to claim 1, characterized in that: The humidity-regulating heat exchanger is equipped with a flue gas moisture content monitoring instrument.