Round heat storage direct combustion type denitration hot blast stove

Abstract

The utility model relates to the technical field of hot-blast stoves, in particular to a circular heat storage direct-fired denitration hot-blast stove which comprises a circular hot-blast stove body and oxidation catalysis checker bricks, a concentric circle layered design is adopted, the inner layer is a combustion area provided with a combustor heat storage chamber, and the outer layer is a heat storage catalysis area filled with the oxidation catalysis checker bricks; the catalyst is used for catalytically oxidizing CO and NMHC non-methane total hydrocarbon in sintering flue gas within the range of 180-300 DEG C, and meanwhile, the catalyst is matched with a combustion-supporting air adjusting valve to achieve combustion / heat storage cycle switching. The effects of efficient denitration, energy conservation and consumption reduction are achieved, the emission concentration of CO and NMHC non-methane total hydrocarbon in flue gas is remarkably reduced, and the environmental protection performance and the energy utilization efficiency of the hot blast stove are improved.

Description

Technical Field

[0001] This utility model relates to the field of hot blast stove technology, and in particular to a circular regenerative direct-fired denitrification hot blast stove. Background Technology

[0002] The sintering process, as a crucial step in steel smelting, accounts for approximately 8%-10% of total energy consumption and 11%-15% of carbon emissions. It also generates dust, SO2, and NO. x Emissions of atmospheric pollutants such as CO account for as much as 20%-70% of total emissions. With the joint issuance of the "Opinions on Promoting the Implementation of Ultra-Low Emissions in the Steel Industry" by five ministries including the Ministry of Ecology and Environment, which clearly states the goal of steel enterprises in key regions completing ultra-low emission transformation by the end of 2025, new opportunities and challenges have emerged for the development of sintering flue gas treatment technologies. Particularly in the field of sintering flue gas denitrification, selective catalytic reduction (SCR) technology has attracted widespread attention due to its high efficiency. However, the low temperature of sintering flue gas restricts its direct application in the steel industry, necessitating the development of new denitrification technologies adapted to low-temperature conditions.

[0003] To address the denitrification challenge caused by the low temperature of sintering flue gas, existing technologies primarily involve heating the flue gas to the required reaction temperature using a denitrification hot blast stove or direct-fired furnace. Furthermore, to fully utilize the chemical energy in the sintering flue gas and achieve synergistic treatment of pollutants, various methods have been employed, including traditional burner heating, porous media regenerative thermal technology, and catalytic oxidation methods. While these technologies have solved some problems to a certain extent, they still have many limitations in practical applications.

[0004] While the aforementioned technologies can address the issues of heating sintering flue gas and removing pollutants to some extent, significant shortcomings remain. On one hand, existing technologies generally rely on external fuel heating, resulting in high energy consumption and difficulty in effectively utilizing the potential chemical energy of CO and NMHC (non-methane hydrocarbons) in sintering flue gas. On the other hand, low-calorific-value fuels such as blast furnace gas are prone to unstable combustion in traditional burners, and the high cost of catalytic materials limits their large-scale industrial application. Therefore, how to achieve effective removal and resource utilization of CO and NMHC from sintering flue gas while reducing energy consumption has become a pressing technical challenge. Utility Model Content

[0005] In view of the deficiencies in the existing technology, the purpose of this utility model is to provide a circular regenerative direct-fired denitrification hot air furnace.

[0006] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0007] A circular regenerative direct-fired denitrification hot blast stove includes a circular hot blast stove body and an array of oxidation catalytic grid bricks. The circular hot blast stove body adopts a concentric layered design, with the inner layer being the combustion zone and the outer layer being the regenerative catalytic zone. The combustion zone is equipped with a burner regenerative chamber, and the regenerative catalytic zone is filled with oxidation catalytic grid bricks. The oxidation catalytic grid bricks are used to catalytically oxidize CO and NMHC (non-methane total hydrocarbons) in sintering flue gas within a temperature range of 180-300℃.

[0008] Preferably, the matrix material of the oxidation catalytic checker brick is mullite corundum.

[0009] Preferably, the surface of the oxidation catalytic checker brick is coated with a non-precious metal oxide catalyst, which includes oxides of Cu, oxides of Cr, and oxides of Mn.

[0010] Preferably, the circular hot air furnace body is equipped with a combustion air regulating valve to achieve switching between combustion and heat storage cycles.

[0011] Preferably, the burner regenerator chamber is located at the center of the circular hot blast stove body.

[0012] Preferably, the oxidation catalytic grid bricks are arranged in a concentric circle structure.

[0013] Preferably, the porosity of the oxidation catalytic checker brick is 45%.

[0014] Preferably, the geometry of the oxidation catalytic checkerboard brick is a porous honeycomb structure.

[0015] Preferably, the wall thickness of the oxidation catalytic checker brick is 14 mm.

[0016] Preferably, the size of a single oxidative catalytic checker brick is 300 mm × 300 mm × 200 mm.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. By leveraging the synergistic effect of infrared radiation combustion of blast furnace gas and oxidative catalytic checker bricks, efficient removal of CO and NMHC non-methane total hydrocarbons from sintering flue gas is achieved within a temperature range of 180-300℃, effectively solving the problems of resource waste and pollution associated with CO and NMHC non-methane total hydrocarbons in existing technologies.

[0019] 2. The hot blast stove with a circular regenerator structure makes full use of low-calorific-value fuels such as blast furnace gas for infrared radiation combustion, which significantly improves combustion stability and reduces dependence on external fuels, thus reducing energy consumption;

[0020] 3. The surface of the regenerative catalytic checker brick is coated with a non-precious metal oxide catalyst to achieve efficient conversion of CO and NMHC non-methane total hydrocarbons under low-cost conditions, meet the ultra-low emission transformation requirements of the steel industry, and reduce the operating cost of the denitrification system. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0022] Figure 1 This is a cross-sectional view of the circular regenerative direct-fired denitrification hot air furnace of this utility model;

[0023] Figure 2 This is a side view of the circular regenerative direct-fired denitrification hot air furnace of this utility model.

[0024] In the diagram: 1. Circular hot air furnace body; 2. Burner regenerator chamber; 3. Oxidation catalytic checker bricks; 4. Combustion air regulating valve. Detailed Implementation

[0025] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. The described embodiments are only possible technical implementations of the present invention and not all possible implementations. Those skilled in the art can obtain other embodiments in conjunction with the embodiments of the present invention without creative effort, and these embodiments are also within the protection scope of the present invention.

[0026] The inventors of this application discovered that the sintering process, as a crucial step in steel smelting production, accounts for approximately 8-10% of total energy consumption and 11-15% of total carbon emissions, including dust, SO2, and NO. x Emissions of atmospheric pollutants such as CO account for 20-70%. Therefore, this application mainly adopts the following scheme of "circular hot blast stove body 1 and oxidation catalytic checker bricks 3", which achieves the effect of efficient removal of CO and NMHC non-methane total hydrocarbons and heat recovery in sintering flue gas by integrating infrared radiation combustion and catalytic oxidation functions.

[0027] Example 1

[0028] Combination Figures 1-2 As shown, the circular regenerative direct-fired denitrification hot air furnace provided in the embodiment of this utility model includes a circular hot air furnace body 1 and oxidation catalytic checker bricks 3.

[0029] Among them, the circular hot air furnace body 1 adopts a concentric layered design, with the inner layer being the combustion zone and the outer layer being the heat storage and catalytic zone. By adopting the concentric layered design of the circular hot air furnace body 1, the combustion zone and the heat storage and catalytic zone are separated, which can effectively improve the heat exchange efficiency, optimize the flue gas flow path, and improve the overall performance of the equipment.

[0030] A burner regenerator chamber 2 is installed within the combustion zone. Positioned at the center of the circular hot blast stove body 1, this chamber ensures that the infrared radiation combustion generated by the burner is evenly distributed throughout the combustion zone, thereby improving combustion efficiency and heat exchange efficiency. Combined with the concentric layered design of the circular hot blast stove body 1, this allows for smoother radial flow of flue gas, further enhancing heat exchange. Simultaneously, this layout facilitates functional synergy between the combustion zone and the regenerator catalytic zone, enhancing the combustion stability of low-calorific-value fuels and providing a more stable heat source for sintering flue gas heating. Utilizing infrared radiation combustion solves the problem of unstable combustion of low-calorific-value fuels, while simultaneously improving combustion efficiency and thermal utilization.

[0031] The regenerative catalytic zone is filled with oxidation catalytic checker bricks 3. These checker bricks 3 are used to catalytically oxidize CO and NMHC (non-methane hydrocarbons) in the sintering flue gas within a temperature range of 180-300℃, thereby achieving synergistic treatment of sintering flue gas heating and pollutants. Specifically, the oxidation catalytic checker bricks 3 consist of a matrix material and a catalyst coating. The matrix material is made of mullite-corundum. As the matrix material for the oxidation catalytic checker bricks 3, mullite-corundum possesses excellent high-temperature resistance and mechanical strength, effectively withstanding the high-temperature environment inside the hot blast stove and the thermal stress impact during combustion, ensuring that the checker bricks maintain structural stability and catalytic activity during long-term operation. Simultaneously, this material has good thermal conductivity, which helps improve heat exchange efficiency and further promotes the complete combustion of low-calorific-value fuels and the efficient catalytic oxidation of CO and NMHC in the flue gas.

[0032] The catalyst coating is a non-precious metal oxide, composed of Cu oxide, Cr oxide, and Mn oxide, with a thickness of 0.1 mm, applied to the substrate surface via a spraying process. The catalyst coating exhibits strong adhesion to the substrate material and maintains stability at high temperatures. The non-precious metal oxide catalyst is coated on the surface of the oxidation catalytic checker brick 3, utilizing the Cu oxide, Cr oxide, and Mn oxide to efficiently catalyze the oxidation of CO and NMHC (non-methane hydrocarbons) in the sintering flue gas within a temperature range of 180-300℃. This method significantly improves the conversion rate of CO and NMHC at low temperatures, reduces the dependence of the denitrification system on precious metal catalysts, and thus reduces operating costs. Simultaneously, the catalyst activity and stability are enhanced, ensuring the environmental friendliness and economic efficiency of the combustion process.

[0033] Furthermore, in this embodiment, the oxidation catalytic checker brick 3 has hexagonal pores, a porosity of 45%, a wall thickness of 14 mm, and a single brick size of 300 mm × 300 mm × 200 mm. The porosity of 45% effectively balances gas flow resistance and catalytic reaction contact area. On one hand, this porosity design ensures uniform distribution of flue gas within the checker brick, increasing the contact probability between CO and NMHC (non-methane hydrocarbons) and the catalyst active sites, thereby enhancing the catalytic oxidation efficiency of CO and NMHC. On the other hand, the appropriate porosity reduces gas flow resistance, ensuring smooth flow of flue gas within the hot blast stove, and improving the overall system's operational stability and energy efficiency. The 14 mm wall thickness effectively reduces material usage and the overall weight of the checker brick, thus reducing the load on the hot blast stove. Simultaneously, the thinner wall thickness helps improve heat exchange efficiency, allowing heat from the flue gas to be transferred to the interior of the checker brick more quickly, enhancing heat storage capacity. Furthermore, this design increases the specific surface area of ​​the checker bricks, providing more active sites for the catalytic oxidation of CO and NMHC (non-methane hydrocarbons), thereby further improving the removal efficiency of CO and NMHC. The single brick size of 300 mm × 300 mm × 200 mm ensures the rational arrangement and efficient utilization of the checker bricks within the circular regenerative direct-fired denitrification hot blast stove. This size is compatible with the concentric, layered regenerative catalytic zone, contributing to improved heat exchange efficiency and flue gas flow uniformity, while also facilitating the installation and maintenance of the checker bricks.

[0034] Specifically, the oxidation catalytic checkerboard bricks 3 are arranged in a concentric circle structure to form the outer heat storage catalytic zone. Each layer of checkerboard bricks is bonded together with refractory mortar, ensuring the stability and airtightness of the overall structure. The arrangement of the checkerboard brick array allows the flue gas to flow radially, prolonging the contact time between the flue gas and the checkerboard bricks, thereby improving heat exchange efficiency and catalytic reaction effect.

[0035] Specifically, a burner heat storage chamber 2 is set at the center of the circular hot air furnace body 1 to ensure that the high-temperature flue gas generated by combustion can be evenly distributed in the combustion zone. At the same time, the combustion / heat storage cycle is switched through the combustion air regulating valve 4, and the waste heat of the flue gas is used to preheat the combustion air, further reducing fuel consumption.

[0036] The implementation principle of this embodiment is as follows: Low-calorific-value fuels, such as blast furnace gas, are fully combusted through the generated infrared radiation, releasing a large amount of heat. Simultaneously, the flue gas is heated and catalytically oxidized using oxidation catalytic checker bricks 3. Within a temperature range of 180-300℃, the non-precious metal oxide catalyst can effectively catalytically oxidize CO and NMHC (non-methane total hydrocarbons) in the sintering flue gas, achieving synergistic treatment of pollutants. This integrated design not only reduces energy consumption but also improves heat recovery efficiency, realizing the effective removal and resource utilization of CO and NMHC in the sintering flue gas.

[0037] Example 2

[0038] The difference between this embodiment and the previous embodiment lies in the detailed description of how the combustion air regulating valve 4 achieves the process of preheating the combustion air with waste heat from the flue gas. The combustion air regulating valve 4 is made of high-temperature resistant material and its opening and closing are controlled by an electric actuator, thereby switching the direction of flue gas flow. The configuration of the combustion air regulating valve 4 allows the hot air furnace to flexibly switch between combustion and heat storage modes, fully utilizing the waste heat from the flue gas to preheat the combustion air and further reducing fuel consumption.

[0039] Specifically, the combustion air regulating valve 4 system includes an inlet pipe, an outlet pipe, and a regulating valve body. The inlet pipe and outlet pipe are connected to the combustion zone and regenerative catalytic zone of the circular hot blast stove body 1, respectively, and the regulating valve body is installed between the inlet pipe and the outlet pipe. The combustion air regulating valve 4 body contains a rotary valve core, which is driven by an electric actuator to switch the combustion air volume. The rotary valve core is made of high-temperature resistant ceramic material, possessing excellent wear resistance and corrosion resistance. The combustion air regulating valve 4 works in conjunction with the burner regenerative chamber 2 and the oxidation catalytic checker bricks 3, further improving the overall performance of the hot blast stove.

[0040] Specifically, in combustion mode, the generated high-temperature flue gas enters the heat storage catalytic zone to heat the heat storage catalytic checker bricks; in heat storage mode, cold flue gas enters the heat storage catalytic zone to exchange heat with the heat storage catalytic checker bricks, while combustion air is introduced into the heat storage catalytic zone through combustion air regulating valve 4, absorbs the heat from the heat storage checker bricks, and then enters the combustion zone, thereby achieving efficient recovery of flue gas waste heat and preheating of combustion air.

[0041] The implementation principle of this embodiment is as follows: by setting the combustion air regulating valve 4 system, the switching between combustion and heat storage modes is realized. In combustion mode, high-temperature flue gas heats the heat storage catalytic checker bricks; in heat storage mode, cold flue gas exchanges heat with the heat storage catalytic checker bricks, and at the same time, the combustion air is preheated, further reducing fuel consumption and achieving the goal of energy saving and environmental protection.

[0042] Example 3

[0043] The difference between this embodiment and the previous embodiment lies in the optimized geometry and arrangement of the oxidation catalytic grid bricks 3. This structural design not only increases the catalytic reaction area but also reduces flue gas flow resistance and improves heat exchange efficiency. The oxidation catalytic grid bricks 3 are arranged in a staggered pattern to form an outer heat-retaining catalytic zone. The staggered arrangement makes the flow path of flue gas between the grid bricks more complex, prolonging the contact time between the flue gas and the grid bricks, thereby improving the catalytic reaction effect.

[0044] Furthermore, the oxidation catalytic grid brick 3 adopts a porous honeycomb structure with a pore size of 1 mm and a pore density of 100 pores / cm². This porous honeycomb structure significantly increases the specific surface area, improves the contact efficiency between flue gas and the catalyst, and thus enhances the catalytic oxidation effect of CO and NMHC (non-methane total hydrocarbons). Simultaneously, this structure helps reduce gas flow resistance, optimizes the uniformity of flue gas distribution within the regenerative catalytic zone, and further improves heat exchange efficiency and combustion stability.

[0045] The implementation principle of this embodiment is as follows: by optimizing the geometry and arrangement of the oxidation catalytic checker bricks 3, the catalytic reaction effect and heat exchange efficiency are further improved. The porous honeycomb structure increases the catalytic reaction area, and the staggered arrangement prolongs the contact time between the flue gas and the checker bricks, thereby improving the catalytic reaction effect. This optimized design not only improves the overall performance of the hot blast stove but also reduces energy consumption, achieving the goal of energy conservation and environmental protection.

[0046] In the accompanying drawings of this embodiment, the same or similar reference numerals correspond to the same or similar components. In the description of this application, it should be understood that if terms such as "upper," "lower," "left," and "right" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, they are only for the convenience of describing this application 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. Therefore, the terms used to describe positional relationships in the accompanying drawings are only for illustrative purposes and should not be construed as limiting this patent. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0047] The above are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A circular regenerative direct-fired denitrification hot air furnace, characterized in that: The device includes a circular hot blast stove body and an array of oxidation catalytic grid bricks. The circular hot blast stove body adopts a concentric layered design, with the inner layer being a combustion zone and the outer layer being a heat storage catalytic zone. The combustion zone is equipped with a burner heat storage chamber, and the heat storage catalytic zone is filled with the oxidation catalytic grid bricks. The oxidation catalytic grid bricks are used to catalytically oxidize CO and NMHC (non-methane total hydrocarbons) in sintering flue gas within a temperature range of 180-300℃.

2. The circular regenerative direct-fired denitrification hot air furnace as described in claim 1, characterized in that: The matrix material of the oxidation catalytic checker brick is mullite corundum.

3. The circular regenerative direct-fired denitrification hot air furnace as described in claim 1, characterized in that: The surface of the oxidation catalytic checker brick is coated with a non-precious metal oxide catalyst, which includes oxides of Cu, oxides of Cr, and oxides of Mn.

4. The circular regenerative direct-fired denitrification hot air furnace as described in claim 1, characterized in that: The circular hot air furnace body is equipped with a combustion air regulating valve to achieve switching between combustion and heat storage cycles.

5. The circular regenerative direct-fired denitrification hot air furnace as described in claim 1, characterized in that: The burner regenerator chamber is located at the center of the circular hot blast stove body.

6. The circular regenerative direct-fired denitrification hot air furnace as described in claim 1, characterized in that: The oxidation catalytic grid bricks are arranged in a concentric circle array.

7. The circular regenerative direct-fired denitrification hot air furnace as described in claim 1, characterized in that: The porosity of the oxidation catalytic checker brick is 45%.

8. The circular regenerative direct-fired denitrification hot air furnace as described in claim 1, characterized in that: The geometry of the oxidation catalytic checkerboard brick is a porous honeycomb structure.

9. The circular regenerative direct-fired denitrification hot air furnace as described in claim 1, characterized in that: The wall thickness of the oxidation catalytic checker brick is 14 mm.

10. The circular regenerative direct-fired denitrification hot air furnace as described in claim 1, characterized in that: The single brick size of the oxidation catalytic checker brick is 300 mm × 300 mm × 200 mm.

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