Internal denitrification gas-fired bogie hearth furnace

Abstract

This utility model relates to a gas-fired trolley-type heater with internal denitrification, comprising a furnace body with several main burners mounted on it. The main burners are arranged in pairs facing each other, forming a group. The reversing valves of the two facing main burners are in different operating states, allowing them to operate in different states. Several environmentally friendly small burners are distributed on the furnace body wall, spaced apart from the main burners. The main burners and the environmentally friendly small burners are connected to a fuel pipe via a control valve assembly. This utility model, by incorporating environmentally friendly small burners to form small burner groups, works in conjunction with burner groups consisting of two or four burners to efficiently treat nitrogen oxides within the furnace body, significantly reducing the content of nitrogen oxides and other harmful substances in the flue gas and improving the heater's performance.

Description

Technical Field

[0001] This utility model relates to a gas-fired trolley-type heating furnace, particularly a heating furnace capable of in-furnace denitrification treatment, belonging to the field of industrial heating furnace technology. Background Technology

[0002] Combustion-type furnaces are still the main type of furnace used in industrial heating, especially in fields such as steel forging and heat treatment. This is because combustion-type furnaces have a fast temperature rise and adjustment response, high energy density, and temperatures that can reach over 1000℃. Furthermore, combustion-type furnaces that use natural gas or other fuels produce clean air emissions, mainly consisting of CO2 (carbon dioxide, a product of the reaction between fuel and oxygen), NOx (nitrogen oxides, a product of nitrogen in the air at high temperatures), and H2O (water).

[0003] Combustion-fired boilers have implemented numerous measures to significantly reduce the NOx content in their exhaust gas, a process known as denitrification. However, these measures typically involve heating the boiler to generate nitrogen oxides, then using urea as a catalyst to reduce them, or using flue gas purification devices for absorption. Both of these methods require additional resources and energy to implement.

[0004] If nitrogen oxides can be converted and treated directly inside the furnace, the consumption of additional denitrification materials can be eliminated, thus improving the performance of the heating furnace. Utility Model Content

[0005] The purpose of this utility model is to provide a gas-fired trolley-type heater with internal denitrification. The structure is improved by setting environmentally friendly small burners, which reduces nitrogen oxide emissions and improves the temperature uniformity inside the furnace, thereby improving the performance of the heater.

[0006] To achieve the above-mentioned utility model objectives, this utility model provides a gas-fired trolley-type heater with internal denitrification, including a furnace body on which a plurality of main burners are provided;

[0007] The main burner is a regenerative burner. A reversing valve is installed above the main burner. The reversing valve is a selective three-way valve. The lower part of the reversing valve is connected to the inner cavity of the burner through a connecting pipe. The main body of the reversing valve is a switching valve. There are two channels above the switching valve, which are connected to the air branch pipe and the exhaust branch pipe respectively. The switching valve controls that only the air branch pipe or the exhaust branch pipe is connected to the connecting pipe at any given time.

[0008] The main burners are arranged in pairs facing each other, and the main burners arranged in pairs form a group; the reversing valves of the two main burners facing each other are in different working states, so that the two main burners facing each other are in different working states.

[0009] Several environmentally friendly small burners are distributed on the wall of the furnace body; the environmentally friendly small burners are arranged alternately with the main burner.

[0010] The main burner and the environmentally friendly small burner are connected to the fuel pipe.

[0011] As a further improvement of this utility model, a pressure sensor is provided on the furnace body.

[0012] As a further improvement of this utility model, a pressure relief pipe is provided on the furnace wall near the main exhaust pipe, and an automatic pressure relief valve is installed on the pressure relief pipe. The pressure relief pipe is connected to the main exhaust pipe to control the furnace pressure within the desired range.

[0013] As a further improvement of this utility model, the distance between the environmentally friendly small burner and the main burner is greater than 1.5 meters.

[0014] As a further improvement of this utility model, the environmentally friendly small burner has no air inlet, or the environmentally friendly small burner has an air inlet, and an induced draft fan is provided outside the air inlet of the environmentally friendly small burner, and the air inlet of the induced draft fan is connected to the exhaust branch pipe or the exhaust main pipe.

[0015] As a further improvement of this utility model, the furnace body is a rectangular furnace body, and several main burners are provided on the two sides of the furnace wall along the length direction of the furnace body.

[0016] A group of four main burners consists of two adjacent main burners on the same side of the furnace wall and two adjacent main burners on the opposite side of the furnace wall.

[0017] In a set of main burners, the two main burners diagonally opposite each other are in the same working state, that is, the combustion state or the smoke exhaust state.

[0018] The environmentally friendly small burner is located at the top of the furnace body;

[0019] Several environmentally friendly small burners are grouped together to form a small burner group, and the small burner group is located in the area of ​​a main burner group;

[0020] The flames generated by the main burner and the environmentally friendly small burner are both sprayed perpendicularly to the wall of the furnace body towards the central area of ​​the furnace body.

[0021] Furthermore, both ports on the upper part of the main burner's reversing valve are equipped with manual adjustment valves.

[0022] Furthermore, two main burners are grouped together, and the same-side interfaces of the two reversing valves connected to a group of main burners are connected to the same pipe. The air side is connected to the air intake pipe, and the exhaust side is connected to the exhaust pipe.

[0023] The air intake pipes of each group of main burners are connected to the main air pipe via a branch air pipe, and the main air pipe is then connected to the main air pipe.

[0024] The exhaust pipes of each main burner are connected to the main exhaust pipe via a branch exhaust pipe, and the main exhaust pipe is then connected to the main exhaust pipe.

[0025] This utility model of an internal denitrification gas-fired trolley-type heater uses environmentally friendly small burners to form a small burner group, which works in conjunction with a burner group consisting of two or four burners to efficiently treat nitrogen oxides inside the furnace, while releasing heat energy and reducing the nitrogen oxide content in the flue gas, thereby improving the performance of the heater.

[0026] By installing environmentally friendly small burners at locations far from the main burner, and specifically placing these small burners at the combustion end of the main burner for auxiliary heating, the temperature distribution inside the furnace can be made more uniform. This uniformity of temperature also allows the burner to reduce its design of using thermal radiation to heat distant parts, thus reducing the total fuel consumption. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the overall structure of the gas-fired bogie-type heater with internal denitrification according to this utility model (taking the bogie furnace as an example);

[0028] Figure 2 for Figure 1 Enlarged schematic diagram of the heating furnace section in the diagram;

[0029] Figure 3 This is a side view of the internal structure of the gas-fired trolley-type heater with internal denitrification according to this utility model;

[0030] Figure 4 This is a bottom view of the internal structure of the gas-fired trolley-type heater with internal denitrification according to this utility model. Detailed Implementation

[0031] The specific embodiments of this utility model will be further described in detail below with reference to the accompanying drawings.

[0032] The present invention provides a gas-fired bogie-type heater with internal denitrification. The bogie-type heater is used as an example in the accompanying drawings and the following embodiments.

[0033] The overall structure of the internal denitrification gas-fired trolley-type heater of this utility model is as follows: Figure 1 As shown, a trolley 1 is provided, and a trolley drive 12 is provided below the trolley 1 to drive the trolley 1 to enter and exit the heating furnace 2; the heating furnace 2 is provided with a furnace body 21 that is basically rectangular, and an opening is provided on one side of the furnace body 21 to facilitate the entry and exit of the trolley 1, and a furnace door 22 is provided at the opening.

[0034] Further integration Figure 2 , Figure 3 , Figure 4For the rectangular furnace body 21 and the bogie furnace structure, several main burners 3 are generally provided on both sides of the furnace body 21. The main burners 3 are preferably low-NOx regenerative burners, which generally have a heat storage body made of honeycomb ceramic for heat exchange. The main burners 3 are preferably evenly distributed and arranged in pairs opposite each other.

[0035] In this utility model, the preferred embodiment is as follows: Figure 2 , Figure 4 As shown, two adjacent main burners 3 on the same side of the furnace wall and two adjacent main burners 3 on the opposite side of the furnace wall, totaling four main burners 3, form a main burner group 30. Figure 4 As shown, the four main burners 3 within a main burner group 30 can be numbered A, B, C, and D respectively. When the heating furnace 2 is working, the two diagonally opposite main burners 3 (A and D, B and C) are in the same working state, i.e., combustion state or flue gas exhaust state; as shown Figure 4 As shown, main burners A and D 3 are in combustion mode, injecting fuel and air for ignition and combustion. Meanwhile, adjacent main burners B and C 3 on the same side of the furnace wall are in exhaust mode, expelling the flue gas generated inside the furnace 21. During exhaust, the flue gas flows through a heat storage medium, heating it and storing some of the high-temperature heat energy contained in the flue gas. When the operating state switches, i.e., main burners B and C 3 are in combustion mode while main burners A and D 3 are in exhaust mode, when external air enters the furnace 21 through main burners B and C 3, the air first passes through the heat storage medium. At this time, the heat storage medium is at a high temperature, preheating the air before it is blown into the furnace 21. This reduces the heat absorption effect of the external cold air, achieving energy saving.

[0036] A pressure sensor 24 is installed on the furnace body 21 to monitor the pressure inside the furnace body 21. When the pressure is too high, an alarm will be triggered to troubleshoot the problem.

[0037] A pressure relief pipe 26 is provided on the furnace wall of the furnace body 21 near the main exhaust pipe 8. A pressure relief valve 27 is installed on the pressure relief pipe 26, and the pressure relief pipe 26 is directly connected to the main exhaust pipe 8. When the pressure inside the furnace body 21 is high, the pressure relief valve 27 will be opened automatically, and the pressure will be discharged into the main exhaust pipe 8 through the pressure relief pipe 26, so as to ensure that the pressure inside the furnace body 21 is within the expected range, generally a slightly positive pressure, such as 5-30 Pa, and the furnace pressure can be kept stable even during reversing deflagration.

[0038] A key improvement of this invention is that several environmentally friendly small burners 4 are distributed on the wall of the furnace body 21; the environmentally friendly small burners 4 need to be set at a sufficiently far distance from the main burner 3, and in practice, the interval distance needs to be greater than 1.5 meters. Compared to the applicant's earlier applications, such as the low-NOx, energy-saving dual-purpose regenerative burner in Chinese Patent Publication No. CN118623314A and the internal denitrification trolley-type gas heater in Chinese Patent Publication No. CN221147164U, which employ the following technical solutions: "a carbon monoxide inlet pipe communicating with the inner cavity of the furnace body is provided at the top of the furnace body," "the distance between the nozzle of the regenerative burner and the outlet of the carbon monoxide inlet pipe is greater than 1.5 meters," "a carbon monoxide generator is installed outside the furnace body," and "the carbon monoxide generator is connected to the inlet of the carbon monoxide inlet pipe," this utility model directly uses an environmentally friendly small burner 4 to participate in the combustion and heating within the furnace body 21.

[0039] Further preferably, several environmentally friendly small burners 4 are grouped together to form a small burner group 40. The small burner group 40 is located in the area of ​​a main burner group 30 and provides auxiliary heating to the area heated by the main burner group 30. Moreover, within a main burner group 30, multiple environmentally friendly small burners 4 are set in the area away from the main burner 3, so that the temperature is more uniform throughout the furnace body 21.

[0040] In this embodiment, since the furnace body 21 is rectangular, the main burners 3 are arranged on both sides of the furnace body 21. Therefore, the environmentally friendly small burners 4 are preferably arranged at the top of the furnace body 21, taking into account the technical requirements for assisting in increasing the furnace temperature. The combustion flame generated by the environmentally friendly small burners 4 is preferably sprayed downward.

[0041] Both the main burner 3 and the environmentally friendly small burner 4 are connected to the fuel pipe 5, which is generally filled with natural gas. The main component of the natural gas is methane (CH4) (>85%), with the remainder being alkanes, including ethane (C2H6), propane (C3H8), and butane (C4H6). 10 And non-alkane gases, including hydrogen sulfide (H2S).

[0042] Each main burner 3 is equipped with a reversing valve 6 above it. The reversing valve 6 is connected to the air main pipe 7 and the flue gas main pipe 8 through the air branch pipe 72 and the flue gas branch pipe 82, respectively. The end of the flue gas main pipe 8 is connected to the flue gas purification device 9. The flue gas is treated by the flue gas purification device 9 before being discharged, achieving ultra-low emissions (NOx content in the flue gas is less than 50mg / m³).

[0043] The reversing valve 6 is a selective three-way valve. The lower part of the reversing valve 6 is connected to the inner cavity of the main burner 3 via a connecting pipe 64, with the preferred passage being through a heat storage body. The main body of the reversing valve 6 is a switching valve, with its lower part connected to the connecting pipe 64, while its upper part is connected to the air branch pipe 72 and the exhaust branch pipe 82 respectively. The switching valve ensures that only the air branch pipe 72 or the exhaust branch pipe 82 is connected to the connecting pipe 64; that is, when the switching valve connects the air branch pipe 72 to the connecting pipe 64, the path of the exhaust branch pipe 82 is closed. At this time, the main burner 3 connected to the reversing valve 6 is in combustion. In the first state, external air enters the main burner 3 through air branch pipe 72, reversing valve 6, and connecting pipe 64. Similarly, when the switch valve connects exhaust branch pipe 82 to connecting pipe 64, the path of air branch pipe 72 is closed. At this time, the main burner 3 connected to reversing valve 6 is in the exhaust state, and the flue gas in the furnace body 21 is discharged into the exhaust main pipe 8 through the main burner 3, connecting pipe 64, reversing valve 6, and exhaust branch pipe 82. Although the flue gas in the furnace body 21 stores some heat energy in the heat storage body when flowing through the main burner 3, the temperature of the flue gas will still be relatively high, so it is necessary to... The temperature of connecting pipe 64, reversing valve 6, and exhaust branch pipe 82 is monitored to prevent damage to the pipes and valve bodies due to high temperatures. When the temperature of the relevant pipes and valve bodies rises to a high temperature (e.g., 500℃) due to the flow of flue gas, the state of reversing valve 6 needs to be switched to change the working state of the main burner group 30. External cold air is used to cool reversing valve 6 and connecting pipe 64, and the exhaust branch pipe 82 is also allowed to cool down naturally. Alternatively, the temperature of the heat storage body inside the main burner 3 is monitored. When the temperature of the heat storage body inside the main burner 3 on the exhaust side rises to 1000℃, the temperature is monitored. When the temperature of the heat storage medium in the main burner 3 on the combustion side drops to 200℃, the state of the switching valve 6 can be triggered to change the working state of the main burner group 30 in order to improve the heat exchange efficiency of the heat storage medium. Generally speaking, the temperature of the above-mentioned facilities and equipment can be detected, and then the switching cycle of the four switching valves 6 in a group of main burners 30 can be set, which is generally 30~90 seconds, to switch the working state of the four main burners 3 in a group of main burners 30, thereby improving the heat exchange efficiency of the heat storage medium and ensuring the safe working temperature of the relevant components.

[0044] Two opposing burners 3 are grouped together and connected to their reversing valves 6. Each of the two upper ports of the reversing valve 6 is equipped with a manual adjusting valve 63, which allows adjustment of the port opening. The ports on the same side of the two opposing reversing valves 6 are connected to the same connecting pipe, i.e., the air side is simultaneously connected to the air inlet pipe 61, and the exhaust side is simultaneously connected to the exhaust outlet pipe 62. The air inlet pipes 61 of each group of burners 3 are connected to the main air pipe 71 via an air branch pipe 72, and the main air pipe 71 is then connected to the main air pipe 7. Similarly, the exhaust outlet pipes 62 of each group of burners 3 are connected to the main exhaust pipe 81 via an exhaust branch pipe 82, and the main exhaust pipe 81 is then connected to the main exhaust pipe 8. This connection structure ensures that the air inlet pipe 61 to the main air pipe 7, and the exhaust pipe 62 to the main exhaust pipe 8, are parallel paths. This prevents rapid connections along a single main pipe from causing varying pressures at different points due to their distance from the main pipe, resulting in significant differences in air intake and exhaust volumes and affecting temperature uniformity within the furnace body 21. By installing a manual regulating valve 63 at the interface of each reversing valve 6, the opening degree can be further adjusted, resulting in more uniform airflow velocity or exhaust gas velocity entering each burner 3, thus ensuring temperature uniformity within the furnace body 21.

[0045] When the main burner 3 is in combustion mode, it injects air heated by the heat storage body while injecting fuel. The air mainly contains oxygen (O2, 21%) and nitrogen (N2, 78%). The oxygen and fuel are fully combined for combustion. At high temperature, the nitrogen combines with the excess oxygen to produce nitrogen oxides (mainly nitric oxide / NO, and a small amount of nitrogen dioxide / NO2, and trace amounts of nitrous oxide / N2O and other unstable nitrogen oxides).

[0046] While the main burner 3 heats the furnace body 21, the content of nitrogen oxides / NOx increases with the increase of temperature. Especially when the temperature is above 1000℃, nitrogen in the air reacts directly with oxygen, and the nitrogen oxides / NOx will increase sharply. Moreover, as the heat storage body efficiently heats the incoming air, the air is more likely to be heated to above 1000℃, which further aggravates the generation of nitrogen oxides / NOx.

[0047] The purpose of setting up the environmentally friendly small burner 4 is to react nitrogen oxides with carbon monoxide / CO. Fuel is introduced into the environmentally friendly small burner 4 for combustion. Because it is far from the main burner 3 (the main burner 3 in combustion state injects air), it is in a low-oxygen environment. The fuel injected from the environmentally friendly small burner 4 undergoes incomplete combustion in the furnace body 21, producing a large amount of carbon monoxide / CO. This carbon monoxide / CO combines and reacts with nitrogen oxides in the surrounding air to produce more stable carbon dioxide / CO2 and nitrogen / N2, thus reducing the nitrogen oxide content.

[0048] 2CO + 2NO = 2CO2 + N2, temperature > 780℃;

[0049] 4CO + 2NO2 = 4CO2 + N2, temperature > 780℃.

[0050] The environmentally friendly small burner 4 is connected to the fuel pipe. However, because it is necessary to adjust the fuel flow rate according to the generation of nitrogen oxides, and generate an appropriate amount of carbon monoxide to reduce nitrogen oxides, the size of the combustion flame at the environmentally friendly small burner 4 will change significantly with the fuel flow rate. In addition, the burner 3 in the exhaust state will discharge the surrounding low NOx content flue gas under the action of the exhaust fan. If the fuel pressure at the environmentally friendly small burner 4 is low at this time, it will be affected by the fuel flowing rapidly to the main burner 3 in the exhaust state, so that the fuel cannot be fully burned and is discharged as flue gas.

[0051] As a further improvement of this utility model, the environmentally friendly small burner 4 is provided with an air inlet, and an induced draft fan is provided at the air inlet. The air outlet of the induced draft fan is also the air inlet of the environmentally friendly small burner 4. The air inlet of the induced draft fan is connected to the nearby exhaust branch pipe 82 or exhaust main pipe 8. In this embodiment, the end of the air inlet is perpendicular to the top of the furnace body 21 and points downwards. When the induced draft fan is working, it inputs the flue gas in the exhaust branch pipe 82 or exhaust main pipe 8 into the environmentally friendly small burner 4 and blows it downwards. Since there is almost no oxygen in the flue gas, the fuel sprayed from the environmentally friendly small burner 4 is still burning in a low-oxygen environment. The fuel mixes with the returning flue gas, and the sprayed flue gas carries the fuel vertically downwards. The increased combustion range expands the area from which carbon monoxide is produced in a low-oxygen environment, allowing for the treatment of nitrogen oxides within the furnace body 21 over a wider area. Simultaneously, the recirculating flue gas directs the flames from fuel combustion downwards, further heating the central area of ​​the furnace body 21 and improving thermal energy utilization. The increased flame area also enhances the uniformity of temperature within the furnace. In particular, the induced draft fan's flue gas recirculation allows the fuel and flames ejected from the four small environmentally friendly burners to remain within the furnace body 21 for a longer period, extending the interaction time between carbon monoxide / CO and nitrogen oxides / NOx, thus achieving more efficient denitrification within the furnace.

[0052] This utility model of an internal denitrification gas-fired trolley-type heater, by setting up environmentally friendly small burners 4 to form a small burner group 40, cooperates with the main burner group 30 composed of two or four main burners 3, to carry out efficient nitrogen oxide treatment within the furnace body 21, thereby releasing heat energy and reducing the nitrogen oxide content in the flue gas.

[0053] By setting environmentally friendly small burners 4 at a distance from the main burner 3, and specifically setting environmentally friendly small burners 4 at the combustion end of the main burner 3 for auxiliary heating, the temperature distribution inside the furnace can be made more uniform. The uniformity of temperature also allows the main burner 3 to appropriately reduce the design of using thermal radiation to heat the far end, thereby reducing the total fuel consumption.

[0054] The preferred embodiments of this utility model have been described in detail above, but this utility model is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of this utility model, and these equivalent modifications or substitutions are all included within the scope defined by the claims of this application.

Claims

1. A gas-fired trolley-type heater with internal denitrification, including a furnace body, on which several main burners are installed; The main burner is a regenerative burner. A reversing valve is installed above the main burner. The reversing valve is a selective three-way valve. The lower part of the reversing valve is connected to the inner cavity of the burner through a connecting pipe. The main body of the reversing valve is a switching valve. There are two channels above the switching valve, which are connected to the air branch pipe and the exhaust branch pipe respectively. The switching valve controls that only the air branch pipe or the exhaust branch pipe is connected to the connecting pipe at any given time. characterized in that The main burners are arranged in pairs facing each other, and the main burners arranged in pairs form a group; the reversing valves of the two main burners facing each other are in different working states, so that the two main burners facing each other are in different working states. Several environmentally friendly small burners are distributed on the wall surface of the furnace; The environmentally friendly small burner is spaced apart from the main burner; The main burner and the environmentally friendly small burner are connected to the fuel pipe.

2. The internally denitration gas trolley heating furnace according to claim 1, characterized in that, A pressure sensor is installed on the furnace body.

3. The internally denitration gas platform car type heating furnace according to claim 1 or 2, characterized in that, The furnace wall is equipped with a pressure relief pipe near the main exhaust pipe, and a pressure relief valve is installed on the pressure relief pipe. The pressure relief pipe is connected to the main exhaust pipe.

4. The internally denitration gas trolley heating furnace according to claim 1, characterized in that, The distance between the environmentally friendly small burner and the main burner is greater than 1.5 meters.

5. The internally denitration gas platform car type heating furnace according to claim 1 or 4, characterized in that, The environmentally friendly small burner has no air inlet, or the environmentally friendly small burner has an air inlet, and an exhaust fan is installed outside the air inlet of the environmentally friendly small burner. The air inlet of the exhaust fan is connected to the exhaust branch pipe or the exhaust main pipe.

6. The internally denitration gas trolley type heating furnace according to claim 5, characterized in that, The furnace body is rectangular, and several main burners are installed on the two sides of the furnace wall along the length of the furnace body; A group of four main burners consists of two adjacent main burners on the same side of the furnace wall and two adjacent main burners on the opposite side of the furnace wall. In a set of main burners, the two main burners diagonally opposite each other are in the same working state, that is, the combustion state or the smoke exhaust state. The environmentally friendly small burner is located at the top of the furnace body; Several environmentally friendly small burners are grouped together to form a small burner group, and the small burner group is located in the area of ​​a main burner group; The flames generated by the main burner and the environmentally friendly small burner are both sprayed perpendicularly to the wall of the furnace body towards the central area of ​​the furnace body.

7. The internally denitration gas trolley heating furnace according to claim 6, characterized in that, The two ports on the upper part of the main burner's reversing valve are equipped with manual adjustment valves.

8. The internally denitration gas trolley heating furnace according to claim 7, characterized in that, Two main burners facing each other form a group. The same-side interfaces of the two reversing valves connected to a group of main burners are connected to the same pipe. The air side is connected to the air intake pipe, and the exhaust side is connected to the exhaust pipe. The air intake pipes of each group of main burners are connected to the main air pipe via a branch air pipe, and the main air pipe is then connected to the main air pipe. The exhaust pipes of each main burner are connected to the main exhaust pipe via a branch exhaust pipe, and the main exhaust pipe is then connected to the main exhaust pipe.

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