A heating furnace suitable for flue gas pretreatment in SCR equipment

Abstract

This utility model discloses a heating furnace suitable for flue gas pretreatment of SCR equipment, belonging to the field of waste gas treatment technology. It includes: a cylinder; a temperature regulating component for maintaining the cylinder temperature within the optimal temperature range for the denitrification reaction, the temperature regulating component including a burner interface located on the side wall of the cylinder and opposite to the flue gas inlet, and a spray gun interface for connecting to a spray alkali solution spray gun; and a high-temperature resistant protective component for protecting the inside of the cylinder, the high-temperature resistant protective component including an inner lining cotton layer, a lightweight castable layer, and a heavy castable layer distributed sequentially from the outside to the inside of the inner wall of the cylinder. This utility model, by connecting the burner interface to the burner and the spray gun interface to the spray alkali solution spray gun, utilizes a bidirectional regulation mechanism of burner heating and spray gun cooling to stably control the flue gas entering the SCR equipment within the optimal reaction range of 280℃-420℃, promoting a more complete and thorough reaction, thereby significantly improving the flue gas denitrification efficiency.

Description

Technical Field

[0001] This utility model relates to the field of waste gas treatment technology, specifically a heating furnace suitable for flue gas pretreatment of SCR equipment. Background Technology

[0002] SCR equipment is a highly efficient and environmentally friendly technology that reduces nitrogen oxide emissions through selective catalytic reduction (SCR). By injecting ammonia water into the exhaust gas, nitrogen oxides are converted into harmless nitrogen and water under the action of a catalyst. It is widely used in the field of industrial flue gas purification. Currently, the denitrification efficiency of SCR equipment is highly dependent on the ambient temperature of the reaction environment. Typically, the flue gas temperature needs to be controlled within the optimal range of 280℃-420℃ to ensure stable catalyst activity and achieve efficient conversion of nitrogen oxides. However, existing SCR denitrification systems generally suffer from insufficient control over flue gas temperature fluctuations, leading to unsatisfactory denitrification results. For example, in industrial production processes, the temperature of flue gas discharged from equipment such as boilers and incinerators fluctuates significantly due to load changes or fuel type switching. When the flue gas temperature is below 280℃, the catalyst activity in the SCR system drops sharply, and the nitrogen oxide conversion efficiency decreases significantly, with denitrification efficiency even falling below 60% under some operating conditions. When the flue gas temperature is above 420℃, not only is the catalyst prone to sintering and deactivation, but it may also lead to an increase in ammonia escape, generating ammonium sulfate that blocks the catalyst pores, causing secondary pollution and further weakening the long-term stable operation capability of the denitrification system. Utility Model Content

[0003] The purpose of this invention is to provide a heating furnace suitable for flue gas pretreatment in SCR equipment, which can create more suitable temperature conditions for the denitrification reaction in SCR equipment, promote a more complete and thorough reaction, and thus significantly improve the flue gas denitrification efficiency, thereby solving the problems mentioned in the background art.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a heating furnace suitable for flue gas pretreatment of SCR equipment, comprising: a cylindrical body, wherein the two ends of the cylindrical body are respectively provided with a flue gas inlet and a flue gas outlet for communicating with the flue of the SCR equipment; A temperature regulating component for maintaining the cylinder temperature within the optimal temperature range for the denitrification reaction includes a burner interface located on the side wall of the cylinder and opposite to the flue gas inlet, and a spray gun interface for connecting to a spray alkali spray gun. The spray gun interface is symmetrically located on the side wall of the cylinder and between the burner interface and the flue gas outlet. A high-temperature resistant protective assembly for protecting the inside of a cylinder, comprising an inner lining cotton layer, a lightweight castable layer, and a heavy castable layer distributed sequentially from the outside to the inside of the inner wall of the cylinder.

[0005] Preferably, the cylinder is a horizontally arranged Q235B steel cylinder with a thickness of 6-10mm.

[0006] Preferably, the axis of the burner interface forms an angle of 30°-45° with the axis of the cylinder, and the inner wall of the burner interface is provided with a high-temperature resistant sealing ring, the sealing ring being made of graphite-reinforced asbestos.

[0007] Preferably, the thickness of the inner lining cotton layer is 18-22 mm, the thickness of the lightweight castable layer is 62-67 mm, and the thickness of the heavyweight castable layer is 113-117 mm.

[0008] Preferably, the inner side of the short-connection part of the flue gas inlet and flue gas outlet of the cylinder is filled with mortar, which is a high-temperature wear-resistant mortar with a maximum service temperature of ≥1200℃ and a compressive strength of ≥20MPa at room temperature.

[0009] Preferably, the end of the spray gun interface is provided with a quick-connect connector, and the quick-connect connector has a built-in one-way valve.

[0010] Preferably, it also includes a temperature monitoring and control system, which includes an inlet temperature sensor, an outlet temperature sensor, and a remote controller; the inlet temperature sensor is installed in the flue at the flue gas inlet, and the outlet temperature sensor is installed in the flue at the flue gas outlet; the remote controller is electrically connected to the inlet temperature sensor, the outlet temperature sensor, the burner connected to the burner interface, and the spray gun water pump connected to the spray gun interface.

[0011] Compared with the prior art, the beneficial effects of this utility model are: 1. This utility model connects the burner interface to the burner and the spray gun interface to the spray gun for spraying alkaline solution. By utilizing the bidirectional adjustment mechanism of burner heating and spray gun cooling, the flue gas entering the SCR equipment can be stably controlled within the optimal reaction range of 280℃-420℃, promoting a more complete and thorough reaction, thereby significantly improving the flue gas denitrification efficiency.

[0012] 2. This utility model connects to a spray gun via a spray gun interface, and uses the spray gun to spray alkaline solution, thus achieving the integration of cooling and pre-denitrification. This avoids excessive humidity in the flue gas caused by cold water spraying, while also reducing the risk of corrosion and blockage of end-of-pipe desulfurization and dust removal equipment, and reducing indirect emissions of pollutants.

[0013] 3. This utility model uses a high-temperature resistant protective component composed of an inner cotton lining layer, a lightweight castable layer, and a heavy castable layer. This component can effectively isolate the cylinder from the erosion of high-temperature flue gas, improve the service life of the cylinder, and at the same time, the pre-treated clean flue gas can reduce the wear and tear on the terminal equipment and lower the operation and maintenance costs of the terminal equipment. Attached Figure Description

[0014] Figure 1 This is a structural block diagram of the heating furnace of this utility model; Figure 2 This is a schematic diagram of the heating furnace structure of this utility model; Figure 3 This is a schematic diagram of the stacked structure of the high-temperature resistant protective component of this utility model.

[0015] In the diagram: 1. Cylinder body; 2. Flue gas outlet; 3. Flue gas inlet; 4. High-temperature resistant protective components; 41. Inner cotton lining layer; 42. Lightweight castable layer; 43. Heavyweight castable layer; 5. Spray gun interface; 6. Burner interface; 7. Inlet temperature sensor; 8. Outlet temperature sensor. Detailed Implementation

[0016] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0017] Please see Figure 1-3 This utility model provides a technical solution: a heating furnace suitable for flue gas pretreatment of SCR equipment, including a cylinder 1, a temperature regulating component for maintaining the temperature of the cylinder 1 in the optimal temperature range of the denitrification reaction, a high-temperature resistant protective component 4 for protecting the inside of the cylinder 1, and a temperature monitoring and control system. The two ends of the cylinder 1 are respectively provided with a flue gas inlet 3 and a flue gas outlet 2 for communicating with the flue of the SCR equipment. The flue gas outlet 2 is connected to the catalyst reactor inlet of the SCR equipment through the flue. The length of the flue between the heating furnace and the SCR equipment is ≤5m. The flue length of ≤5m can minimize the temperature loss and pressure loss of the flue gas during the transmission process, avoid the flue gas temperature from deviating from the optimal reaction range again due to the excessive transmission distance, and reduce the residence time of the flue gas in the flue, thereby reducing the risk of pollutant deposition and blockage of the flue. The flue needs to be made of high-temperature resistant and corrosion-resistant materials, and the inner wall of the flue needs to be smooth to reduce the flow resistance of the flue gas. The cylinder 1 is a horizontally arranged Q235B steel cylinder, and the thickness of the cylinder 1 is 6-10mm; The inner side of the short-connection section between the flue gas inlet 3 and the flue gas outlet 2 of the cylinder 1 is filled with mortar. The mortar is a high-temperature wear-resistant mortar with a maximum operating temperature of ≥1200℃ and a compressive strength of ≥20MPa at room temperature. When filling, the mortar should be evenly applied to the gaps inside the short-connection section to ensure full filling. After the mortar has cured, its sealing performance and structural strength should be checked. The high-temperature wear-resistant mortar can maintain stable structure and sealing performance even in high-temperature environments (maximum withstanding 1200℃). It fills the gaps at the inlet and outlet short-connection section, preventing high-temperature flue gas from leaking out of the gaps. At the same time, its wear-resistant properties can resist the scouring and wear of the interface section by the flue gas flow. The compressive strength of ≥20MPa at room temperature can enhance the structural strength of the inlet and outlet short-connection section, avoiding interface deformation and loosening caused by changes in flue gas pressure and temperature, and maintaining the stability of the overall structure of the equipment.

[0018] The temperature regulation component includes a burner interface 6 opened on the side wall of the cylinder 1 and arranged opposite to the flue gas inlet 3, and a spray gun interface 5 for connecting the spray alkali spray gun. The spray gun interface 5 is symmetrically opened on the side wall of the cylinder 1 and located between the burner interface 6 and the flue gas outlet 2. The axis of the burner interface 6 forms a 30°-45° angle with the axis of the cylinder 1. The burner interface 6 supplies heat to the furnace through a specific angle interface of 30°-45°, ensuring that heat is evenly transferred to the flue gas and avoiding local overheating or uneven temperature. The inner wall of the burner interface 6 is provided with a high-temperature resistant sealing ring. The sealing ring is made of graphite-reinforced asbestos. During installation, it is necessary to ensure that the sealing ring fits tightly with the inner wall of the interface without gaps. At the same time, the size of the sealing ring must match the burner interface 6 to ensure that an effective seal can be formed after the burner is connected. Graphite-reinforced asbestos has excellent high-temperature resistance and sealing performance. When the burner is connected to the interface, the sealing ring can fill the gap between the burner and the interface, preventing high-temperature flue gas from leaking from the gap. At the same time, its high-temperature resistance ensures that the sealing performance does not decrease under the high-temperature environment generated by the burner operation, avoiding flue gas leakage caused by high-temperature failure of the sealing material, effectively preventing high-temperature flue gas leakage, avoiding the risk of burns to operators, reducing the corrosion of surrounding equipment by flue gas, and reducing the potential for safety accidents. The end of the spray gun interface 5 is equipped with a quick-connect fitting. The quick-connect fitting has a built-in one-way valve. The opening direction of the one-way valve must be consistent with the direction of alkali spraying, that is, only alkali is allowed to flow from the spray gun into the cylinder 1, preventing flue gas from flowing out of the interface. During assembly, it must be ensured that the one-way valve core is flexible and has good sealing performance. The quick-connect fitting allows the spray gun to be quickly installed and removed without disassembling the overall structure of the interface, which facilitates the daily inspection, cleaning or replacement of the spray gun and reduces equipment downtime for maintenance. When the spray gun is not connected or spraying is paused, the one-way valve automatically closes under the action of flue gas pressure, preventing the high-temperature flue gas in the cylinder 1 from flowing out of the spray gun interface 5 in the reverse direction. When the spray gun is connected and spraying, the pressure of the alkali pushes the one-way valve to open, ensuring that the alkali smoothly enters the cylinder 1. The high-temperature resistant protective component 4 includes an inner lining cotton layer 41, a lightweight castable layer 42, and a heavy castable layer 43, which are distributed sequentially from the outside to the inside of the inner wall of the cylinder 1.

[0019] The thickness of the inner lining cotton layer 41 is 18-22mm, the thickness of the lightweight castable layer 42 is 62-67mm, and the thickness of the heavyweight castable layer 43 is 113-117mm. The technical parameters of the inner cotton lining layer 41 meet the following requirements: thermal conductivity 0.030-0.042 W / (m·K), operating temperature -120℃ to 700℃, and density 10-180 kg / m³. 3 The fiber diameter is <8μm, the combustion rating is A / A1, the water repellency is ≥99.8%, and it is resistant to strong acid and strong alkali corrosion. The pH value is neutral or weakly alkaline. With its low thermal conductivity (0.030-0.042W / (m・K)), the inner lining cotton can effectively block the transfer of heat from the high-temperature flue gas in the cylinder to the cylinder steel plate, reducing heat loss and protecting the cylinder structure. The wide operating temperature range (-120℃ to 700℃) allows it to adapt to flue gas temperature fluctuations under different working conditions. The high water repellency (≥99.8%) and corrosion resistance can prevent water vapor and acidic substances in the flue gas from causing the inner lining cotton to become damp, moldy or corroded. The neutral / weakly alkaline pH value avoids chemical reactions between the inner lining cotton and other heat-resistant materials, avoiding problems such as heat insulation failure and corrosion damage caused by substandard material performance, ensuring the overall protective effect of the high-temperature protective component 4, and maintaining the long-term stable operation of the equipment. The technical parameters of the lightweight castable layer 42 meet the following requirements: SiO2 content ≤ 55wt%, Al2O3 content ≥ 30wt%, Fe2O3 content ≤ 2.5wt%, and bulk density 1.4-1.5g / cm³. 3 It has an apparent porosity of 55%, a compressive strength of ≥15MPa, and a thermal conductivity of 0.4W / (m·K). The thermal conductivity (0.4W / (m·K)) of the lightweight castable is lower than that of the heavy castable, which can help the inner lining cotton to further enhance the heat insulation effect and reduce heat transfer. At the same time, its compressive strength of ≥15MPa and its specific bulk density and apparent porosity enable it to support the structure of the outer inner lining cotton and the inner heavy castable, and to buffer the thermal expansion and contraction stress caused by temperature changes through the pore structure. The low Fe2O3 content (≤2.5wt%) can avoid the reaction of Fe element with corrosive substances in flue gas, and the high Al2O3 content (≥30wt%) can improve the material's high temperature resistance and corrosion resistance, ensuring that its performance does not degrade under long-term high temperature flue gas environment. Together with the inner lining cotton, it forms a highly efficient heat insulation layer, further reducing the heat dissipation of the furnace body, improving energy utilization efficiency, and reducing the impact of the rise in the external ambient temperature of the cylinder on the surrounding equipment.

[0020] The technical parameters of the heavy castable layer 43 meet the following requirements: bulk density ≥ 2.65 g / cm³ after drying at 110℃.3 The flexural strength is ≥7MPa at 110℃ and ≥10MPa at 1500℃. The linear shrinkage rate after firing at 1300℃ is -0.5%~0%, and the maximum service temperature is 1300℃-1500℃. When it is a heavy-duty high-alumina castable, the Al2O3 content is ≥92wt% and the SiO2 content is ≤0.5wt%. When it is a heavy-duty alkali-resistant castable, the Al2O3 content is 35%-60wt% and the SiO2 content is 35%-60wt%. The high Al2O3 content (especially high alumina) gives the heavy-duty castable excellent high-temperature resistance, allowing it to directly contact high-temperature flue gas (withstanding up to 1500℃) and preventing high-temperature erosion of the inner cylinder. The extremely small linear shrinkage rate after firing (-0.5%~0%) ensures that the material is not easily shrunk or deformed at high temperatures, maintaining structural stability. High-alumina castables with low SiO2 content (≤0.5wt%) can avoid reaction with acidic substances in flue gas, making them suitable for acidic flue gas scenarios. Alkali-resistant castables, with their specific Al2O3 to SiO2 ratio, can react with alkali metal oxides at high temperatures to form a glaze layer, preventing further corrosion of the material by alkali metals. They are suitable for flue gas scenarios containing high alkali metals, such as biomass combustion flue gas. Lightweight and heavyweight castables are designed for different flue gas compositions, such as acidic and high alkali metals, respectively, broadening the application range of heating furnaces and solving the problem of easy corrosion and failure of traditional high-temperature resistant materials under specific flue gas compositions. At the same time, the high bulk density and high flexural strength ensure that heavyweight castables are not easily damaged under long-term high temperature and flue gas scouring environments, extending the replacement cycle of high-temperature protective components 4 and reducing equipment operation and maintenance costs. The temperature monitoring and control system includes an inlet temperature sensor 7, an outlet temperature sensor 8, and a remote controller. The inlet temperature sensor 7 is installed in the flue of the flue gas inlet 3, and the outlet temperature sensor 8 is installed in the flue of the flue gas outlet 2. The remote controller is electrically connected to the inlet temperature sensor 7, the outlet temperature sensor 8, the burner connected to the burner interface 6, and the spray gun water pump connected to the spray gun interface 5, respectively. It is used to control the burner to start heating or the spray gun water pump to start spray cooling based on the temperature value detected by the inlet temperature sensor 7.

[0021] The inlet temperature sensor 7 collects the initial temperature of the flue gas entering the heating furnace in real time, while the outlet temperature sensor 8 collects the temperature of the flue gas discharged after treatment. Both types of sensors transmit temperature data to a remote controller in real time. The remote controller presets the optimal temperature range for denitrification (280℃-420℃). When the inlet temperature sensor 7 detects a temperature below the lower limit of the range and the outlet temperature does not meet the standard, the controller sends a command to start the burner for heating. When the inlet temperature is higher than the upper limit of the range and the outlet temperature exceeds the limit, the controller commands the spray gun water pump to start spraying for cooling. At the same time, based on the data feedback from the outlet temperature sensor 8, the controller adjusts the burner heating intensity or the spray gun spray volume in real time to ensure that the outlet flue gas temperature remains stable within the optimal range. This achieves automated and precise temperature regulation, avoiding the lag and error of traditional manual regulation, improving the ease of operation of the heating furnace, and reducing manual intervention costs. Through closed-loop monitoring and real-time control, the fluctuation range of the outlet flue gas temperature is controlled within ±5℃, which is far superior to the ±20℃ fluctuation of traditional systems. This provides a more stable reaction environment for the SCR equipment and further improves the denitrification efficiency.

[0022] The remote controller has a preset temperature threshold: when the inlet temperature sensor 7 detects that the flue gas temperature is <280℃, the remote controller controls the burner to start and heat the flue gas to 280℃-420℃; when the inlet temperature sensor 7 detects that the flue gas temperature is >420℃, the remote controller controls the spray gun water pump to start and spray alkaline solution into the cylinder 1 through the spray gun, so that the flue gas temperature drops to 280℃-420℃. At the same time, the alkaline solution reacts with the nitrogen oxides in the flue gas to achieve pre-denitrification.

[0023] In the treatment of industrial flue gas, the industrial flue gas enters through the flue gas inlet 3 of the cylinder 1, passes sequentially through the temperature regulation component's working area, and then through the internal space of the cylinder 1 covered by the high-temperature resistant protective component 4, before finally exiting through the flue gas outlet 2 and entering the SCR equipment. When the flue gas temperature is below the optimal denitrification range (280℃-420℃), the burner is connected through the burner interface 6 to supply heat to the inside of the cylinder 1 to raise the flue gas temperature. When the flue gas temperature is above the optimal range, the spray gun is connected through the spray gun interface 5 to spray alkaline solution to achieve cooling. At the same time, the alkaline solution neutralizes the nitrogen oxides in the flue gas, completing the pre-denitrification process. The high-temperature resistant protective component 4 provides insulation through multiple layers of materials. The high-temperature resistant properties isolate the cylinder 1 from the erosion caused by the high temperature of the flue gas. The mortar further seals the inlet and outlet gaps to prevent high-temperature flue gas leakage and achieve bidirectional regulation of flue gas temperature, providing stable flue gas temperature for the SCR equipment and solving the problem of low denitrification efficiency caused by temperature fluctuations in traditional SCR systems. The high-temperature resistant protective component 4 extends the service life of the cylinder 1 and avoids damage to the furnace structure by high-temperature flue gas. The mortar filling improves the equipment's sealing performance and reduces the risk of flue gas leakage. In addition, the spray gun spraying alkaline solution can simultaneously complete pre-denitrification, reduce the initial concentration of nitrogen oxides entering the SCR equipment, reduce the processing load of the SCR equipment, and lay the foundation for the fullness of the subsequent denitrification reaction.

[0024] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A heating furnace suitable for flue gas pretreatment in SCR equipment, characterized in that: include: The cylinder (1) has a flue gas inlet (3) and a flue gas outlet (2) at both ends for communicating with the flue of the SCR equipment. A temperature regulating component for maintaining the temperature of the cylinder (1) within the optimal temperature range for the denitrification reaction is provided. The temperature regulating component includes a burner interface (6) located on the side wall of the cylinder (1) and opposite to the flue gas inlet (3) and a spray gun interface (5) for connecting to the spray alkali spray gun. The spray gun interface (5) is symmetrically located on the side wall of the cylinder (1) and between the burner interface (6) and the flue gas outlet (2). A high-temperature resistant protective component (4) for protecting the inside of the cylinder (1) includes an inner lining cotton layer (41), a lightweight castable layer (42) and a heavy castable layer (43) distributed sequentially from the outside to the inside of the inner wall of the cylinder (1).

2. A heating furnace suitable for flue gas pretreatment in SCR equipment according to claim 1, characterized in that: The cylinder (1) is a horizontally arranged Q235B steel cylinder with a thickness of 6-10mm.

3. A heating furnace suitable for flue gas pretreatment in SCR equipment according to claim 2, characterized in that: The axis of the burner interface (6) forms an angle of 30°-45° with the axis of the cylinder (1). The inner wall of the burner interface (6) is provided with a high-temperature resistant sealing ring, and the sealing ring is made of graphite-reinforced asbestos.

4. A heating furnace suitable for flue gas pretreatment in SCR equipment according to claim 3, characterized in that: The thickness of the inner lining cotton layer (41) is 18-22 mm, the thickness of the lightweight castable layer (42) is 62-67 mm, and the thickness of the heavy castable layer (43) is 113-117 mm.

5. A heating furnace suitable for flue gas pretreatment in SCR equipment according to claim 4, characterized in that: The inner side of the short-connection part of the flue gas inlet (3) and flue gas outlet (2) of the cylinder (1) is filled with mortar. The mortar is high temperature wear-resistant mortar with a maximum service temperature of ≥1200℃ and a compressive strength of ≥20MPa at room temperature.

6. A heating furnace suitable for flue gas pretreatment in SCR equipment according to claim 5, characterized in that: The end of the spray gun interface (5) is provided with a quick-connect fitting, and the quick-connect fitting has a built-in one-way valve.

7. A heating furnace suitable for flue gas pretreatment in SCR equipment according to any one of claims 1-6, characterized in that: It also includes a temperature monitoring and control system, which includes an inlet temperature sensor (7), an outlet temperature sensor (8), and a remote controller; the inlet temperature sensor (7) is installed in the flue of the flue gas inlet (3), and the outlet temperature sensor (8) is installed in the flue of the flue gas outlet (2); the remote controller is electrically connected to the inlet temperature sensor (7), the outlet temperature sensor (8), the burner interface (6), and the spray gun water pump connected to the spray gun interface (5).

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