Constant temperature variable air volume sintering waste heat utilization system and method

Abstract

The present application relates to a kind of constant temperature variable air volume sintering waste heat utilization system and method, including ring cooler, ring cooler smoke hood, wind box and flue gas circulation system;Flue gas circulation system includes air intake pipeline, waste heat boiler and with waste heat boiler connection circulating fan, ring cooler air return main pipeline, air return main branch pipeline, air blower and automatic control system, characterized in that, the ring cooler smoke hood is through smoke hood, high-temperature flue gas recovery system, medium-temperature flue gas recovery system and temperature mixing system are arranged in the upper portion of through ring cooler smoke hood, high-temperature flue gas in ring cooler smoke hood and medium-temperature flue gas are introduced into ring cooler waste heat boiler, hot air after heat exchange of ring cooler waste heat boiler, after the pressure increase of circulating fan, by ring cooler air return main pipeline and air return main branch pipeline back to ring cooler lower portion wind box, from bottom to top flow through ring cooler trolley when cooling sinter, and temperature is formed hot air and is sent to ring cooler waste heat boiler again, reach recycling.

Description

Technical Field

[0001] This invention relates to the field of sintering waste heat utilization technology, and in particular to a constant-temperature variable-air-volume sintering waste heat utilization system and method. Background Technology

[0002] Currently, with technological advancements, fully sealed annular coolers are widely used in various engineering projects. The utilization of waste heat from these coolers has also shifted from utilizing only the first and second stages of high-temperature flue gas to a multi-purpose approach. The utilization of waste heat from the upper section of the fully sealed annular cooler mainly involves the following: the higher-temperature flue gas from the first and second stages is introduced into the cooler's waste heat boiler to generate steam for power generation; the third stage flue gas is used for hot air sintering or to produce hot water in a third-stage hot water boiler; and the fourth and fifth stages flue gas are used to preheat cold air. Baffles are installed between the sections of the annular cooler's upper cover to separate the flue gas for each purpose. The highest-temperature section, used for generating steam in the waste heat boiler, is the most economically beneficial, and the efficiency of waste heat power generation from sintering is a crucial indicator for evaluating waste heat utilization efficiency.

[0003] In current engineering designs, waste heat utilization often employs a constant air volume with variable temperature method, where the annular cooler is segmented by baffles. The air volume within the baffles remains relatively stable, and the flue gas temperature depends on the temperature of the sintering exhaust gas. However, under unstable production conditions, significant temperature fluctuations lead to low boiler operational stability. In some cases, high sintering temperatures result in excessively high flue gas temperatures and severe overheating, making the boiler flue material unsuitable for overheating requirements, causing severe deformation, and making repairs and maintenance extremely difficult. Maintaining stable operation of the waste heat boiler, thereby ensuring effective waste heat power generation, is the core issue in annular cooler waste heat utilization. To address this problem, a constant temperature with variable air volume sintering waste heat utilization system is designed. Summary of the Invention

[0004] The purpose of this invention is to provide a system and method for utilizing sintering waste heat with constant temperature and variable air volume.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] This invention discloses a constant-temperature variable-volume sintering waste heat utilization system, comprising an annular cooler, an annular cooler fume hood disposed above the annular cooler, multiple air boxes disposed below the annular cooler, and a flue gas circulation system; the annular cooler is divided into three sections: a high-temperature section, a medium-temperature section, and a low-temperature section; the flue gas circulation system includes an annular cooler waste heat boiler and a circulating fan connected to the annular cooler waste heat boiler, an annular cooler return air main duct, return air branch ducts connected to the air boxes, and a blower; and also includes an automatic control system. The annular cooler fume hood is a through-type annular cooler fume hood, divided into a high-temperature air intake section and a medium-temperature air intake section; a high-temperature flue gas recovery system, a medium-temperature flue gas recovery system, and a temperature mixing system are provided above the high-temperature and medium-temperature air intake sections.

[0007] The high-temperature flue gas recovery system includes a high-temperature air intake duct, a high-temperature air duct, an electric vent valve A, an electric regulating valve A, and a temperature measuring device A. The high-temperature air intake duct is located at the upper part of the high-temperature air intake section of the annular cooler's smoke hood, and its upper end is connected to the vent chimney. The electric vent valve A is located at the upper end of the high-temperature air intake duct. One end of the high-temperature air duct is connected to the high-temperature air intake duct, and the other end is connected to the high-temperature flue gas inlet of the waste heat boiler. The temperature measuring device A is located on the high-temperature air duct, and the electric regulating valve A is located at the high-temperature flue gas inlet of the waste heat boiler. The temperature measuring device A is signal-correlated with the electric regulating valve A.

[0008] The medium-temperature flue gas recovery system includes a medium-temperature air intake duct, a medium-temperature air duct, an electric vent valve B, an electric regulating valve B, and a temperature measuring device B. The medium-temperature air intake duct is located at the upper part of the medium-temperature air intake section of the annular cooler's smoke hood, and its upper end is connected to the vent chimney. The electric vent valve B is located at the upper end of the medium-temperature air intake duct. One end of the medium-temperature air duct is connected to the medium-temperature air intake duct, and the other end is connected to the medium-temperature flue gas inlet of the waste heat boiler. The temperature measuring device B is located on the medium-temperature air duct, and the electric regulating valve B is located at the medium-temperature flue gas inlet of the waste heat boiler. The temperature measuring device B is signal-correlated with the electric regulating valve B.

[0009] The temperature mixing system includes a mixed flue gas intake duct, a connecting pipe, an electric regulating valve C, an electric regulating valve D, a temperature measuring device C, and a temperature measuring device D. The mixed flue gas intake duct is located on the upper part of the flue gas hood of the annular cooler, between the high-temperature intake section and the medium-temperature intake section. The connecting pipe is a tee pipe, consisting of a central main pipe and two branch pipes. One end of the central main pipe is connected to the outlet of the mixed flue gas intake duct, and the other end is located in the middle of the two branch pipes and connected to them. One branch pipe has its port connected to the high-temperature intake duct, and the other branch pipe has its port connected to the medium-temperature intake duct. The electric regulating valve D and the temperature measuring device D, as well as the electric regulating valve C and the temperature measuring device C, are respectively installed on the two branch pipes. The temperature measuring device D is signal-correlated with the electric regulating valve D, and the temperature measuring device C is signal-correlated with the electric regulating valve C. All electric regulating valves and temperature measuring devices are electrically connected to the automatic control system and can be controlled from the control room.

[0010] Furthermore, a cold air valve A is installed in front of the temperature measuring device A in the high-temperature air intake duct, and a cold air valve B is installed in front of the temperature measuring device B in the medium-temperature air intake duct.

[0011] The present invention discloses a method for utilizing sintering waste heat under constant temperature and variable air volume, employing the aforementioned constant temperature and variable air volume sintering waste heat utilization system, characterized in that the method comprises the following steps:

[0012] A. A high-temperature flue gas recovery system, a medium-temperature flue gas recovery system, and a temperature mixing system are installed at the upper part of the high-temperature air intake section and the medium-temperature air intake section of the annular cooler smoke hood to introduce the high-temperature flue gas and medium-temperature flue gas in the high-temperature air intake section and the medium-temperature air intake section of the annular cooler smoke hood into the annular cooler waste heat boiler.

[0013] B. A temperature measuring device A is installed on the high-temperature duct of the high-temperature flue gas recovery system, and an electric regulating valve A is installed at the high-temperature flue gas inlet of the annular cooler waste heat boiler; a temperature measuring device B is installed on the medium-temperature duct of the medium-temperature flue gas recovery system, and an electric regulating valve B is installed at the medium-temperature flue gas inlet of the annular cooler waste heat boiler; an electric regulating valve D and a temperature measuring device D, an electric regulating valve C and a temperature measuring device C are respectively installed on the connecting pipe of the temperature mixing system, in order to control the high-temperature flue gas inlet temperature and the medium-temperature flue gas inlet temperature of the boiler, so that the high-temperature flue gas inlet temperature of the annular cooler waste heat boiler is controlled at 400℃ and the medium-temperature flue gas temperature of the annular cooler waste heat boiler is controlled at 300℃, and an alarm is triggered if the fluctuation range exceeds ±10℃.

[0014] C. The hot air at 130℃~150℃ after heat exchange in the waste heat boiler of the annular cooler is pressurized by the circulating fan and returned to the lower air box of the annular cooler through the main return air pipe of the annular cooler and the return air branch pipe connected to the air box. When it flows from bottom to top through the annular cooler trolley, it cools the sintered ore and heats up to form hot air, which is then sent to the waste heat boiler of the annular cooler to achieve recycling.

[0015] During production operation, the flue gas temperature in the high-temperature section of the annular cooler is 400±50℃, the flue gas temperature in the medium-temperature section is 300±50℃, and the temperature of the mixing system is 350±50℃. The flue gas temperature in the mixing system is between the high-temperature and medium-temperature flue gas temperatures, and its function is to regulate the high-temperature and medium-temperature flue gas temperatures by adjusting the amount of high-temperature and low-temperature flue gas mixed into the mixing system. During normal system operation, both electric regulating valves A and B are fully open.

[0016] If the high-temperature and medium-temperature flue gas in the high-temperature and medium-temperature air intake sections of the annular cooler's flue gas hood are stably operating at 400℃ and 300℃ respectively, the two electric regulating valves D and C on the connecting pipe are closed, and air is drawn through the high-temperature and medium-temperature air intake pipes. The high-temperature flue gas inlet temperature signal is automatically interlocked with the opening of electric regulating valve C, and the medium-temperature flue gas inlet temperature signal is automatically interlocked with the opening of electric regulating valve D. When the high-temperature flue gas inlet temperature or the medium-temperature flue gas inlet temperature of the annular cooler's waste heat boiler exceeds or falls below the threshold, the automatic control system adjusts the high-temperature flue gas inlet temperature and the medium-temperature flue gas inlet temperature of the annular cooler's waste heat boiler by automatically controlling the opening of electric regulating valve C or electric regulating valve D, so that they are maintained at the set threshold.

[0017] A cooling air valve A is installed in front of the temperature measuring device A in the high-temperature air intake duct, and a cooling air valve B is installed in front of the temperature measuring device B in the medium-temperature air intake duct. When the material discharge temperature of the ring cooler is higher than the normal operating value, and the flue gas inlet temperature still exceeds the limit after the above system automatically adjusts, the central control manually opens the corresponding cooling air valve to keep the flue gas inlet temperature at the set threshold.

[0018] Furthermore, when the waste heat boiler of the annular cooler malfunctions and needs maintenance, the electric regulating valves A and B are closed, and the electric regulating valves C and D of the connecting pipe and branch pipe are closed at the same time. The circulating fan is turned off, the blower is turned on, and the electric vent valve A at the top of the high-temperature air intake pipe and the electric vent valve B at the top of the medium-temperature air intake pipe are turned on, so that the annular cooler meets the normal operation requirements of the sintering system.

[0019] The advantages of this invention are:

[0020] By adopting the aforementioned constant-temperature variable-volume sintering waste heat utilization system, the air volume can be flexibly adjusted through various regulation methods to maintain a stable temperature entering the waste heat boiler of the annular cooler. This avoids damage to equipment and pipes due to overheating and ensures the performance of equipment and pipe materials. At the same time, it avoids problems such as low system efficiency and reduced economy caused by excessively low temperatures, ensuring efficient operation of the system under relatively stable working conditions and improving the overall economic benefits of the system. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of a sintering waste heat utilization system with constant temperature and variable air volume. Detailed Implementation

[0022] The invention will now be further described with reference to the accompanying drawings.

[0023] like Figure 1 As shown, a constant-temperature variable-volume sintering waste heat utilization system of the present invention includes an annular cooler 1, an annular cooler fume hood 11 disposed above the annular cooler, multiple air boxes disposed below the annular cooler 1, and a flue gas circulation system; the annular cooler 1 is divided into three sections: a high-temperature section, a medium-temperature section, and a low-temperature section; the flue gas circulation system includes an annular cooler waste heat boiler 5 and a circulating fan 6 connected to the annular cooler waste heat boiler 5, an annular cooler return air main duct 7, a return air branch duct 9 connected to the air boxes, and a blower 8; and an automatic control system. The annular cooler fume hood 11 is a through-type annular cooler fume hood, which is divided into a high-temperature air intake section and a medium-temperature air intake section. A high-temperature flue gas recovery system, a medium-temperature flue gas recovery system, and a temperature mixing system are provided above the high-temperature air intake section and the medium-temperature air intake section.

[0024] The high-temperature flue gas recovery system includes a high-temperature air intake duct 21, a high-temperature air duct 22, an electric vent valve A25, an electric regulating valve A24, and a temperature measuring device A23. The high-temperature air intake duct 21 is located at the upper part of the high-temperature air intake section of the annular cooler smoke hood 11. The upper end of the high-temperature air intake duct 21 is connected to the vent chimney. The electric vent valve A25 is located at the upper end of the high-temperature air intake duct 21. One end of the high-temperature air duct 22 is connected to the high-temperature air intake duct 21, and the other end is connected to the high-temperature flue gas inlet of the annular cooler waste heat boiler 5. The temperature measuring device A23 is located on the high-temperature air duct 22. The electric regulating valve A24 is located at the high-temperature flue gas inlet of the annular cooler waste heat boiler 5. The temperature measuring device A23 is signal-correlated with the electric regulating valve A24.

[0025] The medium-temperature flue gas recovery system includes a medium-temperature air intake duct 31, a medium-temperature air duct 32, an electric vent valve B35, an electric regulating valve B34, and a temperature measuring device B33. The medium-temperature air intake duct 31 is located at the upper part of the medium-temperature air intake section of the annular cooler smoke hood 11, and its upper end is connected to the vent chimney. The electric vent valve B35 is located at the upper end of the medium-temperature air intake duct 31. One end of the medium-temperature air duct 32 is connected to the medium-temperature air intake duct 31, and the other end is connected to the medium-temperature flue gas inlet of the annular cooler waste heat boiler 5. The temperature measuring device B33 is located on the medium-temperature air duct 32, and the electric regulating valve B34 is located at the medium-temperature flue gas inlet of the annular cooler waste heat boiler 5. The temperature measuring device B33 is signal-correlated with the electric regulating valve B34.

[0026] The temperature mixing system includes a mixed flue gas intake duct 41, a connecting pipe, an electric regulating valve C47, an electric regulating valve D45, a temperature measuring device C48, and a temperature measuring device D46. The mixed flue gas intake duct 41 is located on the upper part of the annular cooler's smoke hood, between the high-temperature intake section and the medium-temperature intake section. The connecting pipe is a tee pipe, consisting of a central main pipe 42 and two branch pipes 43 and 44. One end of the central main pipe 42 is connected to the outlet of the mixed flue gas intake duct 41, and the other end is located in the middle of the two branch pipes and connected to them. The system is connected to the high-temperature air intake pipe 21 via one of the two branch pipes 43, and to the medium-temperature air intake pipe 31 via the other branch pipe 44. Electric regulating valve D45 and temperature measuring device D46, as well as electric regulating valve C47 and temperature measuring device C48, are respectively installed on the two branch pipes. Temperature measuring device D46 is signal-linked to electric regulating valve D45, and temperature measuring device C48 is signal-linked to electric regulating valve C47. All electric regulating valves and temperature measuring devices are electrically connected to the automatic control system and can be controlled from the control room.

[0027] Because the continuous annular cooler fume hood causes the flue gas temperature inside the annular cooler 11 to decrease in stages, during production operation, the flue gas temperature in the high-temperature section of the annular cooler is 400±50℃, the flue gas temperature in the medium-temperature section is 300±50℃, and the temperature of the mixing system is 350±50℃. The flue gas temperature of the mixing system is between the high-temperature and medium-temperature flue gas temperatures, and its function is to regulate the high-temperature and medium-temperature flue gas temperatures by adjusting the amount of high-temperature and low-temperature flue gas mixed into the mixing system.

[0028] The present invention discloses a method for utilizing sintering waste heat at a constant temperature and with variable air volume, the method comprising the following steps:

[0029] A. A high-temperature flue gas recovery system, a medium-temperature flue gas recovery system and a temperature mixing system are provided at the upper part of the high-temperature air intake section and the medium-temperature air intake section of the annular cooler smoke hood 11 to introduce the high-temperature flue gas and medium-temperature flue gas in the high-temperature air intake section and the medium-temperature air intake section of the annular cooler smoke hood into the annular cooler waste heat boiler 5.

[0030] B. A temperature measuring device A23 is installed on the high-temperature duct 22 of the high-temperature flue gas recovery system, and an electric regulating valve A24 is installed at the high-temperature flue gas inlet of the annular cooler waste heat boiler 5. A temperature measuring device B33 is installed on the medium-temperature duct 32 of the medium-temperature flue gas recovery system, and an electric regulating valve B34 is installed at the medium-temperature flue gas inlet of the annular cooler waste heat boiler 5. An electric regulating valve D45 and a temperature measuring device D46, as well as an electric regulating valve C47 and a temperature measuring device C48, are respectively installed on the connecting pipe of the temperature mixing system to control the high-temperature flue gas inlet temperature and the medium-temperature flue gas inlet temperature of the annular cooler waste heat boiler.

[0031] C. The hot air at 130℃~150℃ after heat exchange in the waste heat boiler of the annular cooler is pressurized by the circulating fan 6 and then flows through the main return air pipe 7 of the annular cooler and the return air branch pipe 9 connected to the air box to the lower air box of the annular cooler. As it flows from bottom to top through the annular cooler trolley, it cools the sintered ore and heats it up to form hot air, which is then sent to the waste heat boiler 5 of the annular cooler to achieve recycling.

[0032] This invention controls the high-temperature flue gas inlet temperature and the medium-temperature flue gas inlet temperature of the annular cooler waste heat boiler. It includes setting the high-temperature flue gas inlet temperature of the annular cooler waste heat boiler to 400°C and the medium-temperature flue gas temperature of the annular cooler waste heat boiler to 300°C in the automatic control system, and triggering an alarm if the fluctuation range exceeds ±10°C.

[0033] During production operation, when the system is running normally, the electric regulating valves A24 and B24 are fully open.

[0034] If the flue gas in the high-temperature and medium-temperature air intake sections of the annular cooler's flue gas hood 11 is operating stably at 400℃ and 300℃ respectively, the two electric regulating valves D45 and C47 on the connecting pipe are closed, and air is drawn through the high-temperature air intake pipe 21 and the medium-temperature air intake pipe 31. The high-temperature flue gas inlet temperature signal is automatically interlocked with the opening of the electric regulating valve C47, and the medium-temperature flue gas inlet temperature signal is automatically interlocked with the opening of the electric regulating valve D45. When the high-temperature flue gas inlet temperature or the medium-temperature flue gas inlet temperature of the annular cooler's waste heat boiler exceeds or falls below the threshold, the automatic control system adjusts the high-temperature flue gas inlet temperature and the medium-temperature flue gas inlet temperature of the annular cooler's waste heat boiler by automatically controlling the opening of the electric regulating valve F47 or the electric regulating valve E45, so that the high-temperature flue gas inlet temperature of the annular cooler's waste heat boiler is controlled at 400±10℃ and the medium-temperature flue gas temperature of the annular cooler's waste heat boiler is controlled at 300±10℃.

[0035] When the waste heat boiler of the annular cooler malfunctions and requires maintenance, close electric regulating valves A24 and B34, and simultaneously close electric regulating valves C47 and D45 of the connecting pipe and branch pipe. Turn off circulating fan 6, turn on blower 8, and open electric vent valves A25 at the top of the high-temperature air intake pipe and B35 at the top of the medium-temperature air intake pipe to ensure the annular cooler meets the normal operating requirements of the sintering system. Electric regulating valves A24 and B34 can also be used as backups, with manual adjustment of their opening to regulate the temperature of the high-temperature or medium-temperature flue gas inlet of the waste heat boiler of the annular cooler.

[0036] In this invention, a cooling air valve A26 is installed in front of the temperature measuring device A23 in the high-temperature air intake duct 21, and a cooling air valve B36 is installed in front of the temperature measuring device B33 in the medium-temperature air intake duct 31. When the material discharge temperature of the ring cooler is higher than the normal operating value, and the flue gas inlet temperature still exceeds the normal operating temperature after the above system automatically adjusts, the central control manually opens the corresponding cooling air valve to keep the flue gas inlet temperature at the set threshold.

[0037] The system of this invention is flexible and versatile in operation. The signals from the electric regulating valves and temperature measuring devices at various locations are all led to the control room. By coordinating various adjustment methods, it is possible to achieve constant temperature and variable air volume adjustment by using only high temperature air intake pipes, medium temperature air intake pipes and mixed flue gas air intake pipes.

Claims

1. A method for utilizing sintering waste heat with constant temperature and variable air volume, employing a sintering waste heat utilization system with constant temperature and variable air volume, the system comprising an annular cooler, an annular cooler fume hood disposed above the annular cooler, multiple air boxes disposed below the annular cooler, and a flue gas circulation system; the annular cooler is divided into three sections: a high-temperature section, a medium-temperature section, and a low-temperature section; the flue gas circulation system comprises an annular cooler waste heat boiler and a circulating fan connected to the annular cooler waste heat boiler, an annular cooler return air main duct, return air branch ducts connected to the air boxes, and a blower; and further comprising an automatic control system, characterized in that... The aforementioned annular cooler smoke hood is a through annular cooler smoke hood, which is divided into a high-temperature air intake section and a medium-temperature air intake section. A high-temperature flue gas recovery system, a medium-temperature flue gas recovery system, and a temperature mixing system are provided at the top of the high-temperature air intake section and the medium-temperature air intake section. The high-temperature flue gas recovery system includes a high-temperature air intake duct, a high-temperature air duct, an electric vent valve A, an electric regulating valve A, and a temperature measuring device A. The high-temperature air intake duct is located at the upper part of the high-temperature air intake section of the annular cooler's smoke hood, and its upper end is connected to the vent chimney. The electric vent valve A is located at the upper end of the high-temperature air intake duct. One end of the high-temperature air duct is connected to the high-temperature air intake duct, and the other end is connected to the high-temperature flue gas inlet of the waste heat boiler. The temperature measuring device A is located on the high-temperature air duct, and the electric regulating valve A is located at the high-temperature flue gas inlet of the waste heat boiler. The temperature measuring device A is signal-correlated with the electric regulating valve A. The medium-temperature flue gas recovery system includes a medium-temperature air intake duct, a medium-temperature air duct, an electric vent valve B, an electric regulating valve B, and a temperature measuring device B. The medium-temperature air intake duct is located at the upper part of the medium-temperature air intake section of the annular cooler's smoke collection hood, and its upper end is connected to the vent chimney. The electric vent valve B is located at the upper end of the medium-temperature air intake duct. One end of the medium-temperature air duct is connected to the medium-temperature air intake duct, and the other end is connected to the medium-temperature flue gas inlet of the waste heat boiler. The temperature measuring device B is located on the medium-temperature air duct, and the electric regulating valve B is located at the medium-temperature flue gas inlet of the waste heat boiler. The temperature measuring device B is signal-correlated with the electric regulating valve B. The temperature mixing system includes a mixed flue gas intake duct, a connecting pipe, an electric regulating valve C, an electric regulating valve D, a temperature measuring device C, and a temperature measuring device D. The mixed flue gas intake duct is located on the upper part of the flue gas hood of the annular cooler, between the high-temperature intake section and the medium-temperature intake section. The connecting pipe is a tee pipe, consisting of a central main pipe and two branch pipes. One end of the central main pipe is connected to the outlet of the mixed flue gas intake duct, and the other end is located in the middle of the two branch pipes and connected to them. One branch pipe has its port connected to the high-temperature intake duct, and the other branch pipe has its port connected to the medium-temperature intake duct. The electric regulating valve D and the temperature measuring device D, as well as the electric regulating valve C and the temperature measuring device C, are respectively installed on the two branch pipes. The temperature measuring device D is signal-correlated with the electric regulating valve D, and the temperature measuring device C is signal-correlated with the electric regulating valve C. All electric regulating valves and temperature measuring devices are electrically connected to the automatic control system and can be controlled from the control room. The method includes the following steps: A. Introduce the high-temperature and medium-temperature flue gas from the high-temperature and medium-temperature air intake sections of the annular cooler's smoke hood into the annular cooler's waste heat boiler. B. Electric regulating valve D and temperature measuring device D, electric regulating valve C and temperature measuring device C are respectively installed on the connecting pipe of the temperature mixing system to control the inlet temperature of the high-temperature flue gas and the inlet temperature of the medium-temperature flue gas in the boiler, so that the inlet temperature of the high-temperature flue gas in the waste heat boiler of the annular cooler is controlled at 400℃ and the temperature of the medium-temperature flue gas in the waste heat boiler of the annular cooler is controlled at 300℃. An alarm is triggered if the fluctuation range exceeds ±10℃. C. The hot air at 130℃~150℃ after heat exchange in the waste heat boiler of the annular cooler is pressurized by the circulating fan and returned to the lower air box of the annular cooler through the main return air pipe of the annular cooler and the return air branch pipe connected to the air box. When it flows from bottom to top through the annular cooler trolley, it cools the sintered ore and heats up to form hot air, which is then sent to the waste heat boiler of the annular cooler to achieve recycling.

2. The method for utilizing sintering waste heat under constant temperature and variable air volume according to claim 1, characterized in that: During production operation, the flue gas temperature in the high-temperature section of the annular cooler is 400±50℃, the flue gas temperature in the medium-temperature section is 300±50℃, and the temperature of the mixing system is 350±50℃. The flue gas temperature of the mixing system is between the high-temperature and medium-temperature flue gas temperatures. Its function is to regulate the high-temperature and medium-temperature flue gas temperatures by adjusting the amount of high-temperature and low-temperature flue gas mixed into the mixing system. During normal operation of the system, the electric regulating valves A and B are fully open. If the high-temperature and medium-temperature flue gas in the high-temperature and medium-temperature air intake sections of the annular cooler's flue gas hood are stably operating at 400℃ and 300℃ respectively, the two electric regulating valves D and C on the connecting pipe are closed, and air is drawn through the high-temperature and medium-temperature air intake pipes. The high-temperature flue gas inlet temperature signal is automatically interlocked with the opening of electric regulating valve C, and the medium-temperature flue gas inlet temperature signal is automatically interlocked with the opening of electric regulating valve D. When the high-temperature flue gas inlet temperature or the medium-temperature flue gas inlet temperature of the annular cooler's waste heat boiler exceeds or falls below the threshold, the automatic control system adjusts the high-temperature flue gas inlet temperature and the medium-temperature flue gas inlet temperature of the annular cooler's waste heat boiler by automatically controlling the opening of electric regulating valve C or electric regulating valve D, so that they are maintained at the set threshold. A cooling air valve A is installed in front of the temperature measuring device A in the high-temperature air intake duct, and a cooling air valve B is installed in front of the temperature measuring device B in the medium-temperature air intake duct. When the material discharge temperature of the ring cooler is higher than the normal operating value, and the flue gas inlet temperature still exceeds the limit after the above system automatically adjusts, the central control manually opens the corresponding cooling air valve to keep the flue gas inlet temperature at the set threshold.

3. The method for utilizing sintering waste heat under constant temperature and variable air volume according to claim 1, characterized in that: When the waste heat boiler of the annular cooler malfunctions and needs maintenance, close electric regulating valves A and B, and simultaneously close electric regulating valves C and D of the connecting pipe and branch pipe. Turn off the circulating fan, turn on the blower, and open the electric vent valve A at the top of the high-temperature air intake pipe and the electric vent valve B at the top of the medium-temperature air intake pipe to ensure that the annular cooler meets the normal operating requirements of the sintering system.

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