Calciner flue gas system

Abstract

The utility model provides a kind of calcining furnace smoke wind system, it is related to calcining furnace flue gas treatment technical field, including calcining furnace, burner and flue gas heat exchanger, calcining furnace has hearth and is equipped with the fuel-air mixture inlet and high-temperature flue gas outlet of intercommunication hearth;Burner is equipped with combustion air inlet, and the outlet of burner is communicated with fuel-air mixture inlet;Flue gas heat exchanger has low-temperature side and high-temperature side, and the low-temperature side of flue gas heat exchanger is suitable for the combustion air of being passed into, and the low-temperature side outlet of flue gas heat exchanger is communicated with combustion air inlet, and the high-temperature side inlet of flue gas heat exchanger is communicated with high-temperature flue gas outlet, and the high-temperature flue gas of the high-temperature side of flue gas heat exchanger can be exchanged with the combustion air of the low-temperature side of flue gas heat exchanger.The utility model can utilize the high-temperature flue gas of calcining furnace to preheat its required combustion air, so that flue gas waste heat is recycled to calcining furnace by combustion air, reduce the fuel consumption of calcining furnace, also reduce the flue gas temperature of emission, realize flue gas waste heat recovery.

Description

Technical Field

[0001] This utility model relates to the field of flue gas treatment technology for calcining furnaces, and in particular to a flue gas system for calcining furnaces. Background Technology

[0002] A calcining furnace is a device for high-temperature heating of powdery or filter cake materials. It can be classified into coal-fired furnaces, gas-fired furnaces, oil-fired furnaces, and electric heating furnaces according to the energy source used. Calcination furnaces are mainly used for processes such as activation, oxidation, pyrolysis, and reduction. In the aforementioned processes, the calcining furnace will generate high-temperature flue gas containing dust and acid. At the same time, the flue gas temperature and flue gas volume also have the characteristics of large periodic fluctuations, making the treatment of flue gas quite difficult.

[0003] In related technologies, the treatment of flue gas from calcining furnaces typically employs a combination of natural cooling flue gas cooling and alkaline spraying. However, this method requires the natural cooling flue gas to be installed outdoors, which requires a large area and limits its application. Furthermore, the waste heat from the flue gas is directly diffused into the atmosphere through the natural cooling flue gas, resulting in a significant waste of energy. Utility Model Content

[0004] This utility model aims to at least partially solve one of the technical problems in the related art.

[0005] Therefore, embodiments of this utility model propose a calcining furnace flue gas system. This calcining furnace flue gas system can utilize the high-temperature flue gas of the calcining furnace to preheat the required combustion air, so that the waste heat of the flue gas can be recycled back into the calcining furnace through the combustion air, thereby reducing the fuel consumption of the calcining furnace and lowering the temperature of the emitted flue gas, thus realizing the recovery of waste heat from the flue gas.

[0006] A calcining furnace flue gas system according to an embodiment of the present invention includes a calcining furnace, a burner, and a flue gas heat exchanger. The calcining furnace has a furnace chamber and is provided with a fuel-air mixture inlet and a high-temperature flue gas outlet communicating with the furnace chamber. The burner is provided with a fuel inlet and a combustion air inlet for mixing fuel and combustion air. The outlet of the burner is connected to the fuel-air mixture inlet to introduce the fuel-air mixture into the furnace chamber. The flue gas heat exchanger has a low-temperature side and a high-temperature side. The low-temperature side of the flue gas heat exchanger is suitable for introducing combustion air. The low-temperature side outlet of the flue gas heat exchanger is connected to the combustion air inlet. The high-temperature side inlet of the flue gas heat exchanger is connected to the high-temperature flue gas outlet to introduce high-temperature flue gas into the high-temperature side of the flue gas heat exchanger. The high-temperature flue gas on the high-temperature side of the flue gas heat exchanger can exchange heat with the combustion air on the low-temperature side of the flue gas heat exchanger.

[0007] According to the calcining furnace flue gas system of this utility model embodiment, fuel can be introduced into the burner through the fuel inlet, while the combustion air inlet is used to introduce combustion air into the burner so that the fuel and combustion air can be mixed evenly in a certain proportion in the burner to form a fuel-air mixture. The fuel-air mixture is sent into the furnace of the calcining furnace through the burner outlet and the fuel-air mixture inlet, where it is stably ignited and fully combusted. The heat released by combustion is transferred to the process materials in the calcining furnace to achieve high-temperature heating of the process materials. At the same time, the high-temperature flue gas generated by combustion is discharged through the high-temperature flue gas outlet and enters the high-temperature side of the flue gas heat exchanger. Since the combustion air first enters the low-temperature side of the flue gas heat exchanger and then is sent into the burner, the high-temperature flue gas on the high-temperature side of the flue gas heat exchanger... The flue gas can exchange heat with the combustion air on the low-temperature side of the flue gas heat exchanger. That is, the high-temperature flue gas releases heat to preheat the combustion air before it enters the burner, while the combustion air absorbs heat to cool the high-temperature flue gas. Therefore, by setting up a flue gas heat exchanger to transfer the heat of the high-temperature flue gas to the combustion air required by the calcining furnace, the temperature of the combustion air is increased and the temperature of the exhaust flue gas is reduced. This method can cool the high-temperature flue gas without the need for a natural cooling flue, requires little space, is not limited by the location of use, and achieves full utilization of energy. Therefore, compared with related technologies, this utility model can use the high-temperature flue gas of the calcining furnace to preheat the required combustion air, so that the waste heat of the flue gas can be recycled back to the calcining furnace through the combustion air, reducing the fuel consumption of the calcining furnace and reducing the temperature of the exhaust flue gas, thus realizing the recovery of waste heat from the flue gas.

[0008] In some embodiments, the flow direction of the combustion air on the low-temperature side of the flue gas heat exchanger is opposite to the flow direction of the high-temperature flue gas on the high-temperature side of the flue gas heat exchanger.

[0009] In some embodiments, the flue gas heat exchanger includes a heat exchange body and a cooling element, with at least a portion of each of the low-temperature side and the high-temperature side of the flue gas heat exchanger located outside the heat exchange body; the cooling element is used to cool the high-temperature flue gas on the high-temperature side of the flue gas heat exchanger, and the cooling element is detachably connected to the heat exchange body.

[0010] In some embodiments, the flue gas heat exchanger further includes a dust removal device for cleaning the heat exchange body.

[0011] In some embodiments, the flue gas system further includes a first fan, the air inlet of which is connected to the outside air, and the air outlet of which is connected to the low-temperature side inlet of the flue gas heat exchanger. The first fan is used to provide power for conveying combustion air.

[0012] In some embodiments, the flue gas system further includes a main pipeline, a purification device, and a chimney. The first end of the main pipeline is connected to the high-temperature outlet of the flue gas heat exchanger. The second end of the main pipeline, the purification device, and the chimney are connected in sequence. The purification device is used to purify the flue gas after heat exchange.

[0013] In some embodiments, the flue gas system further includes a second fan, which is provided on the main pipeline. The second fan is located between the high-temperature side outlet of the flue gas heat exchanger and the purification device, and is used to provide conveying power for the heat-exchanged flue gas.

[0014] In some embodiments, at least one of the first fan and the second fan is a variable frequency speed control fan.

[0015] In some embodiments, the flue gas system further includes a branch duct, a first end of which is connected to the outside air and a second end of which is connected to the main duct. The branch duct is used to introduce branch air into the main duct to adjust the temperature of the flue gas after heat exchange in the main duct.

[0016] The second end of the branch pipeline is located between the high-temperature side outlet of the flue gas heat exchanger and the air inlet of the second fan.

[0017] In some embodiments, the flue gas system further includes a mixing valve, which is provided on the branch duct and is used to control the amount of branch air introduced from the branch duct to the main duct.

[0018] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the calcining furnace flue gas system according to an embodiment of the present utility model.

[0020] Figure label:

[0021] 1. Calcining furnace; 11. Furnace chamber; 12. Air-fuel mixture inlet; 13. High-temperature flue gas outlet;

[0022] 2. Burner; 21. Fuel inlet; 22. Combustion air inlet;

[0023] 3. Flue gas heat exchanger; 31. Low-temperature side of flue gas heat exchanger; 32. High-temperature side of flue gas heat exchanger;

[0024] 4. First fan;

[0025] 5. Main pipeline;

[0026] 6. Purification device;

[0027] 7. Chimney;

[0028] 8. Second fan;

[0029] 9. Branch pipeline; 91. Mixing valve. Detailed Implementation

[0030] The embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0031] like Figure 1 As shown in the figure, a calcining furnace flue gas system according to an embodiment of the present invention includes a calcining furnace 1, a burner 2, and a flue gas heat exchanger 3. The calcining furnace 1 has a furnace chamber 11 and is provided with a fuel-air mixture inlet 12 and a high-temperature flue gas outlet 13 communicating with the furnace chamber 11. The burner 2 is provided with a fuel inlet 21 and a combustion air inlet 22 for mixing fuel and combustion air. The outlet of the burner 2 is connected to the fuel-air mixture inlet 12 to introduce the fuel-air mixture into the furnace chamber 11. The flue gas heat exchanger 3 has a low-temperature side and a high-temperature side. The low-temperature side 31 of the flue gas heat exchanger is suitable for introducing combustion air. The outlet of the low-temperature side 31 of the flue gas heat exchanger is connected to the combustion air inlet 22. The inlet of the high-temperature side 32 of the flue gas heat exchanger is connected to the high-temperature flue gas outlet 13 to introduce high-temperature flue gas into the high-temperature side 32 of the flue gas heat exchanger. The high-temperature flue gas on the high-temperature side 32 of the flue gas heat exchanger can exchange heat with the combustion air on the low-temperature side 31 of the flue gas heat exchanger.

[0032] According to the calcining furnace flue gas system of this utility model embodiment, fuel can be introduced into the burner 2 through the fuel inlet 21, while the combustion air inlet 22 is used to introduce combustion air into the burner 2 so that the fuel and combustion air can be mixed evenly in a certain proportion in the burner 2 to form a fuel-air mixture. The fuel-air mixture is sent into the furnace 11 of the calcining furnace 1 through the outlet of the burner 2 and the fuel-air mixture inlet 12, where it is stably ignited and fully combusted. The heat released by combustion is transferred to the process materials in the calcining furnace 1 to achieve high-temperature heating of the process materials. At the same time, the high-temperature flue gas generated by combustion is discharged through the high-temperature flue gas outlet 13 and enters the high-temperature side 32 of the flue gas heat exchanger. Since the combustion air first enters the low-temperature side 31 of the flue gas heat exchanger and then is sent into the burner 2, the flue gas heat exchanger 3... The high-temperature flue gas on the high-temperature side 32 can exchange heat with the combustion air on the low-temperature side 31 of the flue gas heat exchanger. That is, the high-temperature flue gas releases heat to preheat the combustion air before it enters the burner 2, while the combustion air absorbs heat to cool the high-temperature flue gas. Therefore, by setting up the flue gas heat exchanger 3 to transfer the heat of the high-temperature flue gas to the combustion air required by the calcining furnace 1, the temperature of the combustion air is increased and the temperature of the exhaust flue gas is reduced. This method can cool the high-temperature flue gas without setting up a natural cooling flue, which takes up little space, is not limited by the place of use, and achieves full utilization of energy. Therefore, compared with related technologies, this utility model can use the high-temperature flue gas of the calcining furnace 1 to preheat the required combustion air, so that the waste heat of the flue gas can be recycled back into the calcining furnace 1 through the combustion air, reducing the fuel consumption of the calcining furnace 1 and reducing the temperature of the exhaust flue gas, thus realizing the recovery of waste heat from the flue gas.

[0033] Specifically, the calcining furnace 1 may be provided with an installation interface for installing the burner 2, so that the calcining furnace 1 and the burner 2 can be used together. The outlet of the low-temperature side 31 of the flue gas heat exchanger and the combustion air inlet 22, as well as the inlet of the high-temperature side 32 of the flue gas heat exchanger and the high-temperature flue gas outlet 13, can be connected by pipes.

[0034] Understandably, during the heat transfer process of the flue gas heat exchanger 3, particulate matter and some harmful substances in the flue gas can adhere to the surface of the flue gas heat exchanger 3. Therefore, the flue gas heat exchanger 3 can also settle most of the flue gas dust, reduce the dust content of the flue gas, reduce the operating pressure of the subsequent purification device 6, and help the exhaust gas meet the emission standards.

[0035] It should be noted that "process materials" refers to powdered or filter cake materials that have undergone high-temperature heating treatment in calcining furnace 1.

[0036] In addition, the calcining furnace 1 is usually composed of the main body of the calcining furnace 1, the combustion device, the heat preservation furnace chamber 11, the ventilation and smoke exhaust device, etc. The calcining furnace 1 generally uses combustible gases such as natural gas as fuel, which is fully combusted and has high thermal efficiency. At the same time, the combustion process is easy to control, so it causes less environmental pollution than solid and liquid fuels.

[0037] like Figure 1 As shown, in some embodiments, the flow direction of the combustion air on the low-temperature side 31 of the flue gas heat exchanger is opposite to the flow direction of the high-temperature flue gas on the high-temperature side 32 of the flue gas heat exchanger. In other words, the two are in countercurrent heat exchange. Therefore, while ensuring the heat exchange effect between the two, the waste heat of the flue gas can be recovered to the maximum extent, and the temperature of the preheated combustion air can be increased to further reduce the fuel consumption of the calcining furnace 1.

[0038] In some embodiments, the flue gas heat exchanger 3 includes a heat exchange body and a cooling element (not shown in the figure). At least a portion of each of the low-temperature side 31 and the high-temperature side 32 of the flue gas heat exchanger is located outside the heat exchange body. The cooling element is used to cool the high-temperature flue gas on the high-temperature side 32 of the flue gas heat exchanger. The cooling element is detachably connected to the heat exchange body so that the cooling element can be disassembled and replaced independently. Thus, if one of the two connected components fails, only the corresponding damaged component needs to be replaced to ensure the normal operation of the flue gas heat exchanger 3, without scrapping the entire flue gas heat exchanger 3, thereby further effectively reducing the maintenance cost of the flue gas heat exchanger 3.

[0039] It should be noted that the specific structure and working principle of the heat exchanger body and cooling element can adopt existing technologies in this field, and no specific limitations are made here.

[0040] In some embodiments, the flue gas heat exchanger 3 further includes a dust removal device (not shown in the figure). The dust removal device is used to clean the heat exchange body. The dust removal device can flexibly clean the dust according to the dust accumulation, ensuring the heat exchange effect of the flue gas heat exchanger 3. Similarly, the specific structure, working principle, and connection structure between the dust removal device and the heat exchange body can all adopt the existing technology in the art, and are not specifically limited here.

[0041] like Figure 1 As shown, in some embodiments, the flue gas system further includes a first fan 4, the air inlet of the first fan 4 is connected to the outside air, and the air outlet of the first fan 4 is connected to the low-temperature side 31 inlet of the flue gas heat exchanger. The first fan 4 is used to provide power for conveying combustion air.

[0042] It is understandable that the combustion of the calcining furnace 1 requires the consumption of fuel (such as combustible gases like natural gas), and the combustion of fuel requires fresh air to assist combustion. The first fan 4 can provide power for the fresh air required by the burner 2, while overcoming the resistance of the low-temperature side 31 of the flue gas heat exchanger and the fresh air duct, so that the combustion air can be smoothly supplied to the burner 2, thereby ensuring the normal operation of the calcining furnace 1.

[0043] like Figure 1As shown, in some embodiments, the flue gas system further includes a main pipeline 5, a purification device 6, and a chimney 7. The first end of the main pipeline 5 is connected to the high-temperature side 32 outlet of the flue gas heat exchanger; the second end of the main pipeline 5, the purification device 6, and the chimney 7 are connected in sequence, and the purification device 6 is used to purify the flue gas after heat exchange.

[0044] Understandably, the high-temperature flue gas flows through the high-temperature side 32 of the flue gas heat exchanger and exchanges heat with the low-temperature side 31 of the flue gas heat exchanger to cool down, resulting in heat-exchanged flue gas. The heat-exchanged flue gas is then fed into the purification device 6 along the main pipeline 5, where the purification device 6 washes and absorbs the flue gas, producing purified tail gas that can be emitted in an environmentally friendly manner and is discharged through the chimney 7.

[0045] For example, the purification device 6 can be a wet purification device selected according to the nature of the flue gas generated by calcination. The absorbent inside can be an alkaline solution. The absorbent comes into full contact with the dust-laden flue gas to wash away the dust particles and acid gas, thereby purifying the flue gas and enabling it to meet environmental emission standards.

[0046] like Figure 1 As shown, in some embodiments, the flue gas system further includes a second fan 8. The second fan 8 is installed on the main duct 5 and is located between the high-temperature side outlet 32 ​​of the flue gas heat exchanger and the purification device 6. In other words, the high-temperature side outlet 32 ​​of the flue gas heat exchanger is connected to the inlet of the second fan 8 through a portion of the main duct 5, and the outlet of the second fan 8 is connected to the flue gas inlet of the purification device 6 through the remaining main duct 5. The exhaust outlet of the purification device 6 can be connected to the chimney 7 through a duct. The second fan 8 is used to provide power for conveying the heat-exchanged flue gas.

[0047] Understandably, when the calcining furnace 1 is working normally, the calcining furnace 1 relies on the second fan 8 to exhaust the high-temperature flue gas inside the furnace and maintain the negative pressure and temperature inside the furnace. In addition, the second fan 8 also needs to overcome the resistance of the high-temperature side 32 of the flue gas heat exchanger, the purification device 6, the flue gas pipeline, etc., to ensure the normal flow of flue gas.

[0048] like Figure 1 As shown, in some embodiments, at least one of the first fan 4 and the second fan 8 is a variable frequency speed control fan, that is, the first fan 4 is a variable frequency speed control fan, so as to adjust the amount of combustion air according to the use of the calcining furnace 1; or, the second fan 8 is a variable frequency speed control fan, so as to adjust the amount of flue gas according to the use of the calcining furnace 1; or, both the first fan 4 and the second fan 8 are variable frequency speed control fans.

[0049] It is understandable that the first fan 4 and the second fan 8 are variable frequency speed control fans, which enables the operation of the flue gas system to be linked and adjusted, stable and reliable, with a small footprint and great economic benefits. It achieves the dual goals of energy conservation and emission reduction and green economy, and has good social energy conservation benefits.

[0050] like Figure 1 As shown, in some embodiments, the flue gas system further includes a branch pipe 9, with a first end connected to the outside air and a second end connected to the main pipe 5. The branch pipe 9 is used to introduce branch air into the main pipe 5 to regulate the temperature of the flue gas after heat exchange in the main pipe 5.

[0051] The second end of the branch pipe 9 is located between the high-temperature side outlet 32 ​​of the flue gas heat exchanger and the air inlet of the second fan 8.

[0052] Understandably, in order to avoid excessively high flue gas temperature before entering the purification device 6, which would affect the absorption efficiency or even exceed the equipment's temperature resistance requirements, a branch pipe 9 is installed at the air inlet of the second fan 8. This branch pipe 9 can introduce fresh ambient air (i.e., outside air) into the main pipe 5 to mix with the heat-exchanged flue gas, so that the flue gas temperature entering the purification device 6 is controlled within a suitable range.

[0053] like Figure 1 As shown, in some embodiments, the flue gas system also includes a mixing valve 91. The mixing valve 91 is provided on the branch pipe 9. The mixing valve 91 is used to control the amount of branch air introduced from the branch pipe 9 to the main pipe 5. That is, the mixing valve 91 can adjust the opening at any time according to the actual situation, so that the ambient fresh air and flue gas can be mixed in the pipe, and the temperature of the flue gas entering the purification device 6 can be controlled to ensure the safety of the purification equipment and pipes and the flue gas purification effect.

[0054] Specifically, the inlet of the mixing valve 91 is not connected to a pipe and can directly draw in ambient air, while the outlet of the mixing valve 91 is connected to the branch pipe 9.

[0055] Therefore, compared with related technologies, this utility model uses a flue gas heat exchanger 3 to cool and heat the flue gas of the calcining furnace 1, realizing the recovery of waste heat from the flue gas. Furthermore, the flue gas heat exchanger 3 preheats the combustion air required by the burner 2, and the waste heat from the flue gas is recycled back into the calcining furnace 1 through the combustion air. This is unaffected by flue gas fluctuations, reducing the fuel consumption of the calcining furnace 1. At the same time, it can settle most of the flue gas dust, reduce the flue gas temperature, and reduce the cost of subsequent flue gas treatment. Moreover, the first fan 4 and the second fan 8 are variable frequency speed-regulating fans, which makes the operation of the flue gas system adjustable and stable. It has a small footprint and has great economic benefits, achieving the dual goals of energy conservation and emission reduction and green economy, and has good social energy-saving benefits.

[0056] The present invention will be further illustrated by specific embodiments below.

[0057] Example 1

[0058] In the rare earth polishing powder production process, a calcining furnace 1 is required to calcine the compound at high temperatures. During normal operation, the high-temperature flue gas generated by the calcining furnace 1 can reach 600℃. Therefore, based on the above-mentioned calcining furnace flue gas system, the working process of this flue gas system is as follows:

[0059] 1) The first fan 4 introduces outside air into the combustion air inlet 22 of the burner 2 through the low temperature side 31 of the flue gas heat exchanger. At the same time, fuel is introduced into the burner 2 through the fuel inlet 21. The fuel and combustion air are mixed evenly in a certain proportion in the burner 2 to form a fuel-air mixture. The fuel-air mixture is sent into the furnace 11 of the calcining furnace 1 through the outlet of the burner 2 and the fuel-air mixture inlet 12, where it is stably ignited and fully combusted.

[0060] 2) The second fan 8 discharges the high-temperature flue gas from the furnace chamber 11 of the calcining furnace 1. The combustion air and the high-temperature flue gas of the calcining furnace 1 are exchanged in a countercurrent manner by the flue gas heat exchanger 3. After passing through the flue gas heat exchanger 3, the temperature of the high-temperature flue gas can be reduced from 600℃ to about 200℃, and the temperature of the combustion air can be increased from 30℃ to about 350℃.

[0061] 3) After the high-temperature flue gas is heated by the flue gas heat exchanger 3, the flue gas is heated and then fed into the purification device 6 along the main pipeline 5. The purification device 6 washes and absorbs the flue gas, producing purified tail gas that can be discharged in an environmentally friendly manner and is discharged through the chimney 7.

[0062] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to 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.

[0063] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0064] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0065] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0066] In this utility model, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this utility model. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0067] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A flue gas system for a calcining furnace, characterized in that, include: A calcining furnace, the calcining furnace having a furnace chamber and being provided with an inlet for a fuel-air mixture communicating with the furnace chamber and a high-temperature flue gas outlet; A burner having a fuel inlet and a combustion air inlet for mixing fuel and combustion air, and the burner outlet being connected to the combustion air mixture inlet to introduce the combustion air mixture into the furnace. A flue gas heat exchanger has a low-temperature side and a high-temperature side. The low-temperature side of the flue gas heat exchanger is suitable for introducing combustion air. The outlet of the low-temperature side of the flue gas heat exchanger is connected to the inlet of the combustion air. The inlet of the high-temperature side of the flue gas heat exchanger is connected to the outlet of the high-temperature flue gas to introduce high-temperature flue gas into the high-temperature side of the flue gas heat exchanger. The high-temperature flue gas on the high-temperature side of the flue gas heat exchanger can exchange heat with the combustion air on the low-temperature side of the flue gas heat exchanger. The main pipeline, the first end of which is connected to the high-temperature side outlet of the flue gas heat exchanger; The purification device and the chimney are connected in sequence at the second end of the main pipeline, the purification device and the chimney, and the purification device is used to purify the flue gas after heat exchange; The second fan is installed on the main pipeline. The second fan is located between the high-temperature side outlet of the flue gas heat exchanger and the purification device. The second fan is used to provide conveying power for the heat-exchanged flue gas. A branch pipe, the first end of which is connected to the outside air and the second end of which is connected to the main pipe, is used to introduce branch air into the main pipe to adjust the temperature of the flue gas after heat exchange in the main pipe; The second end of the branch pipeline is located between the high-temperature side outlet of the flue gas heat exchanger and the air inlet of the second fan.

2. The calcining furnace flue gas system according to claim 1, characterized in that, The flow direction of the combustion air on the low-temperature side of the flue gas heat exchanger is opposite to the flow direction of the high-temperature flue gas on the high-temperature side of the flue gas heat exchanger.

3. The calcining furnace flue gas system according to claim 1, characterized in that, The flue gas heat exchanger includes: The heat exchange body, wherein at least a portion of each of the low-temperature side and the high-temperature side of the flue gas heat exchanger is located outside the heat exchange body; A cooling element is provided for cooling the high-temperature flue gas on the high-temperature side of the flue gas heat exchanger, and the cooling element is detachably connected to the heat exchange body.

4. The calcining furnace flue gas system according to claim 3, characterized in that, The flue gas heat exchanger also includes a dust removal device for cleaning the heat exchange body.

5. The calcining furnace flue gas system according to any one of claims 1-4, characterized in that, It also includes a first fan, the air inlet of which is connected to the outside air, and the air outlet of which is connected to the low-temperature side inlet of the flue gas heat exchanger. The first fan is used to provide power for conveying combustion air.

6. The calcining furnace flue gas system according to claim 5, characterized in that, At least one of the first fan and the second fan is a variable frequency speed control fan.

7. The calcining furnace flue gas system according to claim 1, characterized in that, It also includes a mixing valve, which is installed on the branch pipeline and is used to control the amount of branch air introduced into the main pipeline by the branch pipeline.

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