Cross air supply flue gas circulation system of belt type roasting machine suitable for hematite

Abstract

The cross air supply flue gas circulation system comprises the belt type roasting machine and a flue gas circulation system, and the belt type roasting machine comprises a forced air drying section, an air draft drying section, a preheating section, a roasting section, a soaking section and a cooling section in the material flow advancing direction. And the flue gas circulating system comprises a flue gas circulating pipe. In the pellet preparation process, flue gas of the preheating section can be introduced into the cooling section through the arrangement of the flue gas circulating pipe, external air can be introduced into the flue gas circulating pipe through the arrangement of the cold air adding valve, and on the basis that the external air and the flue gas of the preheating section can enter the cooling section together, the cooling effect can be guaranteed, and meanwhile the cooling efficiency is improved. The waste heat of the smoke is utilized, and the amount of smoke exhausted by the system is reduced. Meanwhile, through the cross air supply technology, the heat distribution of the belt type roasting machine is optimized, and the fuel consumption of the roasting section is saved.

Description

Technical Field

[0001] The embodiments of the present application relate to the technical field of pellet production in the iron and steel metallurgical industry, and specifically to a cross-air supply flue gas circulation system for a belt roaster suitable for hematite. Background Art

[0002] Currently, the "belt roaster" pellet production process is one of the main production processes for iron ore pellets. In actual production, the belt roaster is divided into a forced air drying section, an exhaust air drying section, a preheating section I, a preheating section II, a roasting section, a soaking section, and a cooling section along the direction of material flow.

[0003] The traditional hot air process is as follows:

[0004] 1. Front end of cooling section:

[0005] 1.1. Normal temperature air is blown into the cooling section wind box of the belt roaster by the cooling fan, passes through the grate plate of the belt roaster trolley, and then passes through the material layer from bottom to top for heat exchange, and the normal temperature air is converted into high temperature hot air;

[0006] 1.2. There is no partition wall between the cooling section and the soaking section. The high-temperature hot air directly enters the soaking section, passes through the material layer from top to bottom, and enters the soaking section wind box of the belt roaster.

[0007] 1.3. Powered by the reheat fan, the pellets enter the exhaust drying section, pass through the green pellets from top to bottom, and enter the wind box of the exhaust drying section of the belt roaster;

[0008] 1.4. Powered by the main exhaust fan, it enters the subsequent dust removal system and desulfurization and denitrification system and is then discharged into the atmosphere.

[0009] 2. Middle section of cooling section:

[0010] 2.1. Normal temperature air is blown into the cooling section wind box of the belt roaster by the cooling fan. After passing through the grate plate of the belt roaster trolley, it passes through the material layer from bottom to top for heat exchange, and the normal temperature air is converted into high temperature hot air;

[0011] 2.2. The high-temperature hot air passes through the belt roaster furnace cover, is heated by the combustion chambers on both sides of the roasting section upper cover, and then enters the roasting section upper cover. It passes through the material layer from top to bottom and enters the roasting section wind box of the belt roaster;

[0012] 2.3. Powered by the reheat fan, the pellets enter the exhaust drying section, pass through the green pellets from top to bottom, and enter the exhaust drying section bellows of the belt roaster;

[0013] 2.4. The main exhaust fan provides power to the subsequent dust removal system and desulfurization and denitrification system and then discharges it into the atmosphere.

[0014] 3. Hot air from the outlet of the middle and rear sections of the cooling section: The source is the outside normal temperature air

[0015] 3.1. The green balls are dried from bottom to top through the hot air duct and the drying fan into the drying section of the belt roaster;

[0016] 3.2. Finally, it is discharged into the air through the furnace hood dust collector and furnace hood fan.

[0017] 4. Hot air at the last outlet of the cooling section: the source is the outside normal temperature air

[0018] 4.1. Direct discharge.

[0019] There's no wall between the soaking and cooling sections of a belt roaster. Ambient air is pumped upward through the material bed by a blower, generating high-temperature hot air. A heat recovery fan, acting as the power source for both the soaking and roasting sections, draws the high-temperature hot air from the cooling section beneath the material bed. The hot air from the cooling section exits the soaking section, where it can be freely distributed and its temperature cannot be controlled. The hot air from the cooling section passes through the belt roaster's furnace hood and is heated to the desired temperature in combustion chambers on either side of the upper hood before passing through the material bed in the roasting section. The heat source for the soaking section is at the front end of the cooling section, where the hot air displaced is the highest temperature. Therefore, the ideal area for its use is the roasting section, not the soaking section.

[0020] In the belt roaster's airflow system, the flue gas from the forced air drying section, the exhaust air drying section, and the preheating section must all be discharged. The flue gas discharged from the preheating section is particularly hot, and the heat in the flue gas has recycling value. Summary of the Invention

[0021] The Summary of the Invention introduces a series of simplified concepts that will be further described in the Detailed Description of the Invention. This section of the invention is not intended to limit the key features and essential features of the claimed technical solution, nor is it intended to determine the scope of protection of the claimed technical solution.

[0022] The present invention aims to solve at least one of the technical problems existing in the prior art or related art.

[0023] In view of this, the embodiments of the present application propose a method including:

[0024] A belt roaster, which includes a forced air drying section, an exhaust air drying section, a preheating section, a roasting section, a soaking section, and cooling sections I, II, and III along the direction of material flow;

[0025] The flue gas circulation system includes a flue gas circulation pipe, a hot air exchange valve and a cold air exchange valve. One end of the flue gas circulation pipe is connected to the preheating section, and the other end is connected to the cooling section. One end of the cold air exchange valve is connected to the flue gas circulation pipe, and the other end is connected to the external environment. The hot air exchange valve is located at the outlet of the belt roasting machine bellows.

[0026] In a feasible embodiment, the cooling section includes a cooling section I, a cooling section II, and a cooling section III that are connected in sequence; wherein the flue gas circulation pipe includes:

[0027] A main flue gas pipe and two branch pipes, one end of the main flue gas pipe is connected to the preheating section, one end of one branch pipe is connected to the main flue gas pipe and the other end is connected to the cooling section I, and one end of the other branch pipe is connected to the main flue gas pipe and the other end is connected to the cooling section II;

[0028] Wherein, the cold air exchange valve is arranged on each of the branch pipes.

[0029] In a feasible embodiment, the flue gas circulation system further includes:

[0030] A fan, each of the branch pipes is provided with the fan;

[0031] A regulating valve is provided on each branch pipeline;

[0032] A dust removal unit is provided on the main flue gas duct.

[0033] In a feasible embodiment, the cross-air supply flue gas circulation system of the belt roaster suitable for hematite also includes: a cross-air supply duct I, one end of which is connected to the cooling section I, and the other end is connected to the roasting section.

[0034] In a feasible embodiment, a terminal combustion chamber is provided in the roasting section, and the other end of the cross air supply duct I is connected to the terminal combustion chamber of the roasting section.

[0035] In a feasible embodiment, the cross-air supply flue gas circulation system of the belt roaster suitable for hematite also includes: a cross-air supply duct II, one end of the cross-air supply duct II is connected to the cooling II section, and the other end is connected to the equalizing section, and the cross-air supply duct II is arranged crosswise with the cross-air supply duct I.

[0036] In a feasible embodiment, the cross-air supply flue gas circulation system of the belt roaster suitable for hematite further includes: a first partition wall, which is arranged between the cooling section I and the cooling section II.

[0037] In a feasible embodiment, the cross-air supply flue gas circulation system of the belt roaster suitable for hematite further includes: a second partition wall, which is arranged between the soaking section and the cooling section.

[0038] In a feasible embodiment, the cross-air supply flue gas circulation system of the belt roaster applicable to hematite further includes:

[0039] A wind box is arranged in the preheating section, and one end of the flue gas circulation pipe is connected to the wind box.

[0040] Compared with the prior art, the present invention has at least the following beneficial effects:

[0041] The cross-air supply flue gas circulation system for a belt roaster suitable for hematite provided in the embodiment of the present application includes a belt roaster and a flue gas circulation system. The belt roaster includes a blast drying section, an exhaust drying section, a preheating section, a roasting section, a heat equalization section and a cooling section along the direction of material flow. The flue gas circulation system includes a flue gas circulation pipe and a cold air valve. Based on this, during the working process, the green balls manufactured by the external system are first transported to the belt roaster through the distribution system. When the green balls pass through the blast drying section, the blast drying section can output hot air of about 300°C. The hot air is blown from the bottom of the material layer to the top, and then the material is transported to the exhaust drying section. The exhaust drying section supplies hot air from the upper layer of the material to the bottom for drying. Part of the moisture in the green balls can be removed by the blast drying section and the exhaust drying section. Then the green balls enter the preheating section, which gradually heats up the green balls. Then the green balls enter the roasting section, where the temperature can reach above 1250°C. The pellets solidify in the roasting section to form finished balls, which are then transported to the soaking section. The soaking section can complete unfinished chemical reactions and improve the quality of the pellets. After that, the pellets are cooled in the cooling section to complete the product transportation. During the pellet preparation process, the flue gas from the preheating section can be introduced into the cooling section through the setting of the flue gas circulation pipe, and the outside air can be introduced into the flue gas circulation pipe through the setting of the cold air valve. Based on this, the outside air and the flue gas from the preheating section can enter the cooling section together, which can ensure the cooling effect while utilizing the waste heat of the flue gas and reduce the amount of flue gas discharged from the system.

[0042] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are specifically listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present application. The same reference symbols are used throughout the drawings to represent the same components. In the drawings:

[0044] Figure 1This is a schematic structural diagram of a cross-air supply flue gas circulation system for a belt roaster suitable for hematite according to an embodiment provided in the present application.

[0045] in, Figure 1 The corresponding relationship between the reference numerals and component names is as follows:

[0046] 1 belt roaster, 2 flue gas circulation system, 3 cross air supply duct I, 4 cross air supply duct II, 6 first partition wall, 7 second partition wall, 8 bellows;

[0047] 110 blast drying section, 120 exhaust drying section, 130 preheating section, 140 roasting section, 150 soaking section, 160 cooling section, 170 terminal combustion chamber; 161 cooling section I, 162 cooling section II, 163 cooling section III;

[0048] 210 flue gas circulation pipe, 220 cold air exchange valve, 230 fan, 240 regulating valve, 250 dust removal unit, 211 flue gas main pipeline, 212 branch pipeline. DETAILED DESCRIPTION

[0049] In the following description, a number of specific details are provided to provide a more thorough understanding of the technical solutions provided by the present invention. However, it is obvious to those skilled in the art that the technical solutions provided by the present invention can be implemented without one or more of these details.

[0050] It should be noted that the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should also be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of the features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or combinations thereof.

[0051] Exemplary embodiments of the present invention will now be described in greater detail with reference to the accompanying drawings. However, these exemplary embodiments may be implemented in a variety of different forms and should not be construed as being limited to the embodiments set forth herein. It should be understood that these embodiments are provided to make the disclosure of the present invention thorough and complete and to fully convey the concepts of these exemplary embodiments to those of ordinary skill in the art.

[0052] like Figure 1As shown, the embodiment of the present application proposes a belt roaster cross-air supply flue gas circulation system suitable for hematite, including: a belt roaster 1, the belt roaster 1 includes a blast drying section 110, an exhaust drying section 120, a preheating section 130, a roasting section 140, a uniform heat section 150 and a cooling section 160 along the forward direction of the material flow; a flue gas circulation system 2, the flue gas circulation system 2 includes a flue gas circulation pipe 210, a hot air valve and a cold air valve 220, one end of the flue gas circulation pipe 210 is connected to the preheating section 130, and the other end is connected to the cooling section 160, one end of the cold air valve 220 is connected to the flue gas circulation pipe 210, and the other end is connected to the external environment, and the hot air valve is located at the bellows outlet of the belt roaster 1.

[0053] The cross-air supply flue gas circulation system for a belt roaster suitable for hematite provided in an embodiment of the present application includes a belt roaster 1 and a flue gas circulation system 2. The belt roaster 1 includes a blast drying section 110, an exhaust drying section 120, a preheating section 130, a roasting section 140, a soaking section 150, and a cooling section 160 along the direction of material flow. The flue gas circulation system 2 includes a flue gas circulation pipe 210 and a cold air valve 220. Based on this, during operation, the green balls produced by the external system are first transported to the belt roaster 1 through the distribution system. When the green balls pass through the blast drying section 110, the hot air in the blast drying section 110 is blown from the bottom of the material layer to the top. The material is then transported to the exhaust drying section 120. The exhaust drying section 120 supplies hot air from the upper layer of the material downward to extract the material. The blast drying section 110 and the exhaust drying section 120 can remove some moisture from the green balls. The green balls then enter the preheating section 130, which gradually heats up the green balls. The green balls then enter the roasting section 140, which can maintain a stable temperature of over 1250°C. The pellets solidify in the roasting section 140 to form finished balls, which are then transported to the soaking section 150. The soaking section 150 can complete any unfinished chemical reactions and improve the quality of the pellets. The pellets are then cooled in the cooling section 160 and the product is transported. During the pellet preparation process, the flue gas from the preheating section 130 can be introduced into the cooling section 160 through the setting of the flue gas circulation pipe 210, and the outside air can be introduced into the flue gas circulation pipe 210 through the setting of the cold air valve 220. Based on this, the outside air and the flue gas from the preheating section 130 can enter the cooling section 160 together, which can ensure the cooling effect while utilizing the waste heat of the flue gas and reducing the amount of flue gas discharged from the system.

[0054] It can be understood that the material temperature in the cooling section 160 can reach above 1000°C, and the flue gas temperature of the preheating section 130 drawn out through the flue gas circulation pipe 210 is about 300°C. The temperature of the mixed gas formed by mixing the flue gas with the external air will be lower, which is quite different from the material temperature. Therefore, mixing the flue gas and the external air as the gas source of the cooling section 160 can ensure the cooling effect and reduce the amount of flue gas emitted.

[0055] like Figure 1 As shown, in a feasible embodiment, the cooling section 160 includes a cooling section I 161, a cooling section II 162 and a cooling section III 163 connected in sequence; wherein the flue gas circulation pipe 210 includes: a flue gas main pipe 211 and two branch pipes 212, one end of the flue gas main pipe 211 is connected to the preheating section 130, one end of one branch pipe 212 is connected to the flue gas main pipe 211, and the other end is connected to the cooling section I 161, and one end of the other branch pipe 212 is connected to the flue gas main pipe 211, and the other end is connected to the cooling section II 162; wherein, each branch pipe 212 is arranged with a cold air valve 220.

[0056] In this technical solution, the structural composition of the cooling section 160 is further provided. The cooling section 160 may include a cooling section I 161, a cooling section II 162 and a cooling section III 163 connected in sequence, that is, the cooling section I 161 is closer to the heat equalization section 150, and the temperature of the cooling section I 161 is higher than that of the cooling section II 162 and the cooling section III 163.

[0057] This technical solution further provides the structural composition of a flue gas circulation duct 210, which can include a main flue gas duct 211 and two branch ducts 212. The main flue gas duct 211 is used to direct the flue gas from the preheating section 130, while the two branch ducts 212 supply flue gas to cooling section I 161 and cooling section II 162, respectively. Each branch duct 212 is equipped with a cold air valve 220, allowing external air to mix with the flue gas before being distributed to cooling section I 161 and cooling section II 162. This arrangement facilitates the distribution of the flue gas directed from the preheating section 130. The temperature of the flue gas-external air mixture supplied to cooling section I 161 or cooling section II 162 can also be adjusted, further ensuring the cooling effect.

[0058] like Figure 1 As shown, in a feasible embodiment, the flue gas circulation system 2 also includes: a fan 230, each branch pipe 212 is provided with a fan 230; a regulating valve 240, each branch pipe 212 is provided with a regulating valve 240; a dust removal unit 250, the dust removal unit 250 is provided on the flue gas main pipe 211.

[0059] In this technical solution, the flue gas circulation system 2 may further include a fan 230 and a regulating valve 240. Based on this, the fan 230 can be used as a power source for gas circulation, and the regulating valve 240 can be used to adjust the flow rate of the airflow.

[0060] In this technical solution, a dust removal unit 250 may be further provided on the flue gas main duct 211 of the flue gas circulation system 2. The dust removal unit 250 may be used to remove dust from the flue gas, which is more environmentally friendly.

[0061] like Figure 1 As shown, in a feasible embodiment, the cross-air supply flue gas circulation system of the belt roaster suitable for hematite also includes: a cross-air supply duct I3, one end of the cross-air supply duct I3 is connected to the cooling section I 161, and the other end is connected to the roasting section 140.

[0062] In this technical solution, the cross-air supply flue gas circulation system of the belt roaster suitable for hematite can also include a cross-air supply duct I3. One end of the cross-air supply duct I3 is connected to the cooling section I 161, and the other end is connected to the roasting section 140. Based on this and the fact that the temperature of the cooling section I 161 is higher than that of the cooling section II 162 and the cooling section III 163, the cross-air supply duct I3 is provided to transport the airflow in the cooling section I 161 to the roasting section 140, which has the highest heating demand. When used in combination with the flue gas circulation system 2, the waste heat of the flue gas in the preheating section 130 and the waste heat of the material in the cooling section I 161 can be utilized, thereby reducing the energy consumption of pellet preparation, thereby being more environmentally friendly and reducing costs.

[0063] like Figure 1 As shown, in a feasible embodiment, a terminal combustion chamber 170 is provided in the roasting section 140, and the other end of the cross air supply duct I3 is connected to the terminal combustion chamber 170 of the roasting section 140.

[0064] In this technical solution, a conducting position of the cross air supply duct I3 is further provided. The other end of the cross air supply duct I3 is conducted to the end combustion chamber 170 of the roasting section 140, which can further improve the utilization efficiency of waste heat and promote the combustion of the end combustion chamber 170.

[0065] like Figure 1 As shown, in a feasible embodiment, the cross-air supply flue gas circulation system of the belt roaster suitable for hematite also includes: a cross-air supply duct II4, one end of the cross-air supply duct II4 is connected to the cooling II section 162, and the other end is connected to the equalizing section 150, and the cross-air supply duct II4 is cross-arranged with the cross-air supply duct I3.

[0066] In this technical solution, the cross-air supply flue gas circulation system of the belt roaster suitable for hematite can also include a cross-air supply duct II4, one end of the cross-air supply duct II4 is connected to the cooling II section 162 whose temperature is lower than that of the cooling I section 161, and the other end is connected to the equalizing section 150 with lower heating requirements. This setting is used in combination with the cross-air supply duct I3 to form a cross-air supply method, supplying a higher temperature airflow to the roasting section 140 with higher temperature requirements, and supplying a lower temperature airflow to the preheating section 130 with lower temperature requirements, so that the heat energy distribution is more reasonable and more energy-saving.

[0067] like Figure 1 As shown, in a feasible embodiment, the cross-air supply flue gas circulation system of the belt roaster suitable for hematite further includes: a first partition wall 6, and the first partition wall 6 is arranged between the cooling section I 161 and the cooling section II 162.

[0068] like Figure 1 As shown, in this technical solution, the cross-air supply flue gas circulation system of the belt roaster suitable for hematite can also include a first partition wall 6, which is arranged between the cooling section I 161 and the cooling section II 162. The first partition wall 6 blocks the area outside the material conveying path. Such a setting can suppress the heat energy exchange between the cooling section I 161 and the cooling section II 162, and can further improve the cooling efficiency.

[0069] like Figure 1 As shown, in a feasible embodiment, the cross-air supply flue gas circulation system of the belt roaster suitable for hematite further includes: a second partition wall 7, which is arranged between the soaking section 150 and the cooling section 160.

[0070] In this technical solution, the cross-air supply flue gas circulation system of the belt roaster suitable for hematite can also include a second partition wall 7, which is arranged between the equalizing section 150 and the cooling section 160. The second partition wall 7 is set in this way to block the area outside the material conveying path, which can reduce the escape of heat energy from the equalizing section 150 to the cooling section 160, and can further reduce energy consumption.

[0071] like Figure 1 As shown, in a feasible embodiment, the cross-air supply flue gas circulation system of the belt roaster suitable for hematite also includes: a bellows 8, which is arranged in the preheating section 130, and one end of the flue gas circulation pipe 210 is connected to the bellows 8.

[0072] In this technical solution, the cross-air supply flue gas circulation system of the belt roaster suitable for hematite can also include a bellows 8. The arrangement of the bellows 8 makes it easier to transport the airflow.

[0073] The cross-air supply flue gas circulation system for a belt roaster applicable to hematite provided in the embodiment of the present application has the following working process:

[0074] After the hot exhaust gas from the belt roaster 1 is generated in the preheating section 130 of the belt roaster 1, it passes through the bellows 8 and the flue gas circulation system 2 to remove dust before entering the flue gas main duct 211 and two branch ducts 212. The two branch ducts 212 are powered by the fan 230 and go to the cooling section I 161 and cooling section II 162 of the belt roaster 1 respectively.

[0075] A regulating valve 240 is installed on branch pipe 212. This valve regulates the flow of hot air from the preheating section 130's hot exhaust gas to cooling section I 161 and cooling section II 162 to better meet the temperature and oxygen requirements of roasting section 140. Regulating valve 240 is located in front of the cold air mixing valve 220. This placement of regulating valve 240 improves mixing of the hot air.

[0076] A second partition wall 7 is added between the equalizing section 150 and the cooling section 160, and a first partition wall 6 is added between the cooling section I 161 and the cooling section II 162. The hot air at the outlets of the cooling section I 161 and the cooling section II 162 are respectively sent to the roasting section 140 of the belt roasting machine 1 through the cross air supply duct I3 and the cross air supply duct II4 to the end combustion chamber 170 of the roasting section 140 and the equalizing section 150 to achieve reasonable air supply.

[0077] The embodiments of the present application have at least the following beneficial effects:

[0078] 1. The present invention adopts a cross-air supply method, which transports the cooling section I 161 (the front end of the cooling section 160) to the roasting section 140, and the cooling section II 162 (the second front end of the cooling section 160) to the soaking section 150, thereby achieving a more reasonable distribution of heat and saving fuel consumption in the roasting section 140;

[0079] 2. The present invention realizes temperature control of the inlet of the belt roaster 1 soaking section 150 by the regulating valve 240 on the branch pipe 212, without adding a burner in the soaking section 150;

[0080] 3. The present invention adds a flue gas circulation system 2, partially replacing the normal temperature air originally blown in by the cooling fan 230 with the hot exhaust gas from the preheating section 130. This can increase the outlet air temperature of the cooling section 160, provide more heat to the roasting section 140 and the soaking section 150, save fuel consumption in the roasting section 140, utilize the waste heat of the flue gas, and reduce the amount of flue gas discharged from the system.

[0081] 4. The present invention directly connects the cooling section I 161 to the end combustion chamber 170 of the roasting section 140 through the cross air supply duct I3 and the cross air supply duct II4, which has a shorter path and less heat loss;

[0082] 5. The present invention circulates the hot exhaust gas from the preheating section 130 to the front end of the cooling section 160. The oxygen content in the hot exhaust gas from the preheating section 130 is relatively low. The process proposed by the present invention is more suitable for pellet production using hematite as raw material.

[0083] In the present invention, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The term "plurality" refers to two or more, unless expressly limited otherwise. Terms such as "installed," "connected," "connected," and "fixed" should be interpreted broadly. For example, "connected" can mean a fixed connection, a detachable connection, or an integral connection; "connected" can mean a direct connection or an indirect connection through an intermediary. Those skilled in the art will understand the specific meanings of these terms in the present invention based on specific circumstances.

[0084] In the description of the present invention, it should be understood that the directions or positional relationships indicated by terms such as "up", "down", "left", "right", "front" and "back" are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or unit referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limiting the present invention.

[0085] Throughout this specification, terms such as "one embodiment," "some embodiments," and "specific embodiments" mean that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these 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 any one or more embodiments or examples.

[0086] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A cross-air supply flue gas circulation system for a belt roaster suitable for hematite, characterized in that: include: A belt roaster, which includes a forced air drying section, an exhaust air drying section, a preheating section, a roasting section, a soaking section, and cooling sections I, II, and III along the direction of material flow; The flue gas circulation system includes a flue gas circulation pipe, a hot air exchange valve and a cold air exchange valve. One end of the flue gas circulation pipe is connected to the preheating section, and the other end is connected to the cooling section. One end of the cold air exchange valve is connected to the flue gas circulation pipe, and the other end is connected to the external environment. The hot air exchange valve is located at the outlet of the belt roasting machine bellows.

2. The pellet roasting system according to claim 1 is applicable to the cross-air supply flue gas circulation system of the belt roaster of hematite, characterized in that: The cooling section includes a first cooling section, cooling section I, a second cooling section, cooling section II, and a third cooling section, cooling section III, which are connected in sequence; wherein the flue gas circulation pipe includes: A main flue gas pipe and two branch pipes, one end of the main flue gas pipe is connected to the preheating section, one end of one branch pipe is connected to the main flue gas pipe and the other end is connected to the cooling section I, and one end of the other branch pipe is connected to the main flue gas pipe and the other end is connected to the cooling section II; Wherein, the cold air exchange valve is arranged on each of the branch pipes.

3. The cross-air supply flue gas circulation system for a belt roaster suitable for hematite according to claim 2, characterized in that: The flue gas circulation system further comprises: A fan, each of the branch pipes is provided with the fan; A regulating valve is provided on each branch pipeline; A dust removal unit is provided on the main flue gas duct.

4. The cross-air supply flue gas circulation system for a belt roaster suitable for hematite according to claim 2, characterized in that: Also includes: A cross air supply duct I, one end of which is connected to the cooling section I, and the other end is connected to the roasting section.

5. The cross-air supply flue gas circulation system for a belt roaster suitable for hematite according to claim 4, characterized in that: A terminal combustion chamber is provided in the roasting section, and the other end of the cross air supply duct I is connected to the terminal combustion chamber of the roasting section.

6. The cross-air supply flue gas circulation system for a belt roaster suitable for hematite according to claim 5, characterized in that: Also includes: A cross air supply duct II, one end of which is connected to the cooling section II, and the other end is connected to the heat equalization section, and the cross air supply duct II is arranged crosswise with the cross air supply duct I.

7. The pellet roasting system according to claim 2 is applicable to the cross-air supply flue gas circulation system of the belt roaster of hematite, characterized in that: Also includes: A first partition wall is arranged between the first cooling section Cooling Section I and the second cooling section Cooling Section II.

8. The cross-air supply flue gas circulation system for a belt roaster suitable for hematite according to any one of claims 1 to 7, characterized in that: Also includes: A second partition wall is arranged between the soaking section and the cooling section.

9. The cross-air supply flue gas circulation system for a belt roaster suitable for hematite according to any one of claims 1 to 7, characterized in that: Also includes: A wind box is arranged in the preheating section, and one end of the flue gas circulation pipe is connected to the wind box.

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