CN118293687A - Air draft type sintering end point control system and control method with upper and lower alternating internal circulation - Google Patents

Abstract

An up-down alternate internal circulation exhaust type sintering end point control system comprises a sintering trolley, an air box and a large flue. The lower part of the sintering trolley is provided with a plurality of bellows, and the air outlet of each bellows is communicated with a large flue at the lower part. The system also comprises an up-down alternate internal circulation exhaust device arranged at the tail of the sintering machine, and the device comprises an upper exhaust fume hood, a lower exhaust bellows, an internal circulation air pipe and a circulation fan. The upper exhaust fume hood is arranged on the upper part of the sintering trolley at the tail of the sintering trolley. The lower exhaust bellows is arranged at the lower part of the sintering trolley at the tail. The upper exhaust fume hood is communicated with the lower exhaust air box through an internal circulation air pipe. The internal circulation air pipe is provided with a circulation fan. The invention changes bottom air draft into bottom/top up-down adjustable air draft through device improvement, simultaneously implements internal smoke circulation, changes the direction of smoke circulation through adjusting the air draft direction, further changes the up-down moving direction of the combustion belt in the material layer, and achieves the purpose of controlling sintering speed and sintering end point.

Description

A control system and method for sintering endpoint with alternating upper and lower internal circulation ventilation

Technical Field

The invention relates to a sintering endpoint control system and a control method, and in particular to an up-and-down alternating internal circulation exhaust type sintering endpoint control system and a control method, belonging to the technical field of sintering.

Background technique

In the steelmaking process, sintering is a key core link, and its role is to provide high-quality, low-sulfur sintered ore for the ironmaking blast furnace. The sintering process is roughly divided into seven links from beginning to end: batching-mixing-laying-ignition-sintering-cooling-granulation. Among them, the cooling link is to recover the waste heat of the red-hot sintered ore through normal temperature air heat exchange, and use the waste gas after heat exchange to generate steam for power generation. Its operation quality directly affects the energy efficiency index of the entire sintering process.

The schematic diagram of the existing sintering process is shown in Figure 1: the mixed mixed material to be sintered is evenly arranged on the sintering machine trolley through a nine-roller distributor. The sintering machine trolley full of sintered ore first enters the ignition furnace, and the high-temperature flame in the furnace is used to ignite the material surface, ignite the coke powder in the fuel surface and form a high-temperature combustion zone of a certain thickness. Then the trolley leaves the ignition furnace and enters the open exhaust area. As air is drawn into the material layer, the high-temperature combustion zone gradually moves downward. When the trolley carrying the sintering material from the head to the tail of the machine, the high-temperature combustion zone also happens to move from the surface to the bottom layer. At this time, the sintering process is completed, the trolley flips at the large gear at the tail of the machine, and the sintered finished ore is unloaded into the rear-end cooling process. The empty trolley goes back from the bottom to prepare for the next cycle of sintering operations. When the sintering machine is open for exhaust operation, the exhaust duct located at the bottom of the trolley will draw the flue gas after combustion in the combustion zone in the material layer into the large flue. The flue gas drawn out by all the exhaust ducts will eventually be gathered together and sent from the direction of the machine head to the main electrostatic precipitator, desulfurization and denitrification processes, and finally discharged through the main chimney.

The reaction of the material layer in the sintering machine trolley is shown in Figure 2: after the material is laid and ignited, a uniform high-temperature zone is formed on the surface of the sintering material layer. As the lower exhaust is carried out, when the sintering machine trolley reaches the tail position, the high-temperature zone has descended from the upper part of the material layer to the bottom of the material layer. During the operation, the upper part of the high-temperature zone is the sintered finished ore that has been sintered, and the lower part of the high-temperature zone is the mixed material to be sintered.

As the country's requirements for energy conservation and emission reduction in the steel industry continue to increase, the refined production level of the sintering process has also received increasingly stringent requirements. At present, the sintering process has the following defects in the exhaust operation link:

1. Poor control effect of sintering speed: Since the existing sintering process is mainly based on exhaust operation, it has limitations in controlling the sintering speed (i.e. the downward speed of the combustion zone). It relies on the opening and closing of valves on the exhaust duct to control it, which easily leads to incomplete combustion caused by reduced exhaust volume. Moreover, the sintering exhaust ducts are all in series. If individual circulating air valves are closed, the exhaust volume of other ducts will increase uncontrolled, which will lead to poor sintering production effect.

2. The end position of sintering is difficult to control: As mentioned above, since the existing sintering process is mainly based on exhaust operation and the sintering speed cannot be finely controlled, the end position of the entire sintering process is difficult to control. It often happens that when the tail is unloaded, the combustion zone has burned below the bottom layer of the material layer or even burns the grate bars of the trolley, or the combustion zone is still in the middle and has not reached the bottom layer of the material layer. Sometimes, the positions of the combustion zones on the left and right sides are seriously disconnected.

Summary of the invention

In view of the defects of the above-mentioned prior art, the present invention proposes a sintering endpoint control system and control method with an up-and-down alternating internal circulation exhaust type. In the technical solution of the present invention, the existing continuous bottom exhaust mode is changed to an up-and-down exhaust internal circulation mode at the tail of the machine, and an up-and-down alternating internal circulation exhaust device is set at the tail of the sintering machine, and the bottom exhaust is changed to a bottom/top up-and-down adjustable exhaust. At the same time, the internal circulation of the flue gas is implemented, and the direction of the flue gas circulation is changed by adjusting the exhaust direction, so that the combustion zone in the sintering material layer can change its upward and downward moving direction, thereby achieving the purpose of controlling the sintering speed and the sintering endpoint and improving the sintering ore production effect.

According to a first embodiment of the present invention, there is provided a sintering endpoint control system with an upper and lower alternating internal circulation exhaust type.

A sintering endpoint control system with alternating up and down internal circulation exhaust, the system comprises a sintering trolley, a bellows, and a large flue. A plurality of bellows are provided at the lower part of the sintering trolley, and the air outlet of each bellows is connected to the large flue at the lower part. The system also comprises an alternating up and down internal circulation exhaust device arranged at the tail of the sintering machine. The alternating up and down internal circulation exhaust device comprises an upper exhaust hood, a lower exhaust bellows, an internal circulation air duct, and a circulating fan. Among them, the upper exhaust hood is arranged at the upper part of the sintering trolley at the tail. The lower exhaust bellows is arranged at the lower part of the sintering trolley at the tail. The upper exhaust hood and the lower exhaust bellows are connected through the internal circulation air duct. A circulating fan is arranged on the internal circulation air duct.

In the present invention, the upper and lower alternating internal circulation exhaust device also includes a tail circulation header arranged at the lower part of the lower exhaust air box. The air outlet of the lower exhaust air box is connected to the tail circulation header. The upper exhaust hood is connected to the tail circulation header through the internal circulation duct.

Preferably, the tail circulation header is arranged at the side of the large flue, and the tail circulation header is connected to the large flue via a cut-off valve.

In the present invention, an upper exhaust smoke duct pipe is further connected between the upper exhaust smoke hood and the inner circulation air duct. Preferably, a circulation air valve is provided on the upper exhaust smoke duct pipe.

Preferably, n upper exhaust hoods are arranged in the cross-sectional direction of the tail of the sintering machine, and each upper exhaust hood is connected to the inner circulation air duct through its own upper exhaust flue pipe. The value of n is 2-6, preferably 2-4.

In the present invention, the upper exhaust hood includes a hood side plate, a hood reducer, and a hood inner partition. The hood side plate is connected to the sintering trolley. The hood reducer is arranged on the upper part of the hood side plate and is connected to the upper exhaust flue pipe. The hood inner partition is arranged between two adjacent upper exhaust hoods in the cross-sectional direction of the tail of the sintering machine.

In the present invention, the system further comprises a tail section visual recognition device arranged downstream of the tail of the sintering machine.

In the present invention, a pure oxygen spraying device is connected to the inner circulation air duct.

In the present invention, the system further comprises a temperature detection device. The temperature detection device is arranged on each wind box at the bottom of the sintering trolley and the wind box branch pipe of the lower exhaust wind box at the tail.

In the present invention, the system further comprises a control device, which is connected to and controls the operation of the circulating fan, the circulating air valve, the isolation valve, the tail section visual recognition device, and the temperature detection device.

According to a second embodiment of the present invention, a method for controlling an endpoint of a sintering process with alternating upper and lower internal circulation and exhaust ventilation is provided.

A method for controlling an endpoint of a sintering process using an alternating upper and lower internal circulation exhaust type sintering process or a method for controlling an endpoint of a sintering process using an alternating upper and lower internal circulation exhaust type sintering process using the system of the first embodiment, the method comprising the following steps:

1) Open the isolation valve and the system starts to run. The control device observes the cross section of the sintering ore layer at the tail of the machine in real time through the machine tail cross section visual recognition device, and uses this to determine the current sintering end point position.

2) If the current sintering end position is judged to be within the normal range, the control device continues to monitor through the machine tail section visual recognition device. If the current sintering end position is judged not to be within the normal range, the isolation valve is closed, so that the sintering machine enters the internal circulation working mode.

3) The control device further determines whether the current sintering end point position is biased forward or backward through the machine tail section visual recognition device.

If the current sintering end point is judged to be forward, the circulating fan is operated in reverse. If the current sintering end point is judged to be backward, the circulating fan is operated in forward.

This adjustment ends when the control device determines that the current sintering end point position has reached the normal range.

According to a third embodiment of the present invention, a method for controlling an endpoint of a sintering process with alternating upper and lower internal circulation and exhaust ventilation is provided.

A method for controlling an endpoint of a sintering process using an alternating upper and lower internal circulation exhaust type sintering process or a method for controlling an endpoint of a sintering process using an alternating upper and lower internal circulation exhaust type sintering process using the system of the first embodiment, the method comprising the following steps:

1) The isolation valve is opened and the system starts to run. The control device observes the cross section of the sintering ore layer at the tail of the machine in real time through the machine tail cross section visual recognition device, and uses this to determine the current sintering end point position.

2) If it is determined that the current sintering end point position is within the normal range, the control device continues to monitor through the tail section visual recognition device.

If it is determined that the current sintering end position is not within the normal range, the isolation valve is first closed to put the sintering machine into the internal circulation working mode. Then, the control device further determines whether the combustion zone in the material layer is at the same level in the cross-sectional direction of the sintering machine through the machine tail section visual recognition device.

3) If it is determined that the combustion zone is at the same horizontal height in the cross-sectional direction of the sintering machine and the current sintering end point position is biased forward, the circulating fan is reversed.

If it is determined that the combustion zone is at the same horizontal height in the cross-sectional direction of the sintering machine and the current sintering end point position is biased to the rear, the circulating fan is operated in the forward direction.

4) If it is determined that the combustion zone is not at the same level in the cross-sectional direction of the sintering machine, and at the same time, along the running direction of the sintering trolley, the combustion speed on the left side of the sintering material layer is slow and the circulating fan has been set to the reverse mode, then the circulating air valve corresponding to the upper exhaust hood on the left side is adjusted down. Correspondingly, if the combustion speed on the left side of the sintering material layer is slow and the circulating fan has been set to the forward mode, then the circulating air valve corresponding to the upper exhaust hood on the left side is adjusted up.

If it is determined that the combustion zone is not at the same level in the cross-sectional direction of the sintering machine, and at the same time, along the running direction of the sintering trolley, the combustion speed on the right side of the sintering material layer is slow and the circulating fan has been set to the reverse mode, then the circulating air valve corresponding to the upper exhaust hood on the right side is adjusted down. Correspondingly, if the combustion speed on the right side of the sintering material layer is slow and the circulating fan has been set to the forward mode, then the circulating air valve corresponding to the upper exhaust hood on the right side is adjusted up.

This adjustment ends when the control device determines that the current sintering end point position has reached the normal range.

In the present invention, in step 3), the power of the circulating fan is:

W = |(hh ₀ )| × Cp × H × _Vmachine × λ (1).

Where: W is the power of the circulating fan, kW. h is the current sintering end position (here it is represented by the distance between the end position of the sintering process of the material layer and the machine head in the length direction of the sintering machine), m. _h0 is the normal ideal sintering end position, m. _Cp is the volume specific heat capacity of the sintered ore, kJ/(m ³ ·℃). H is the width of the sintering trolley, m. _Vmachine is the speed of the sintering machine, m/min. λ is the power coefficient, and the value range of λ is 5-10 (kW·℃·min)/kJ.

Adjust the motor of the circulation fan so that the power of the circulation fan is W.

Preferably, step 1) further comprises: the control device monitors the smoke temperature of each wind box and the lower exhaust wind box in real time through the temperature detection device.

At this time, the control device determines the current sintering end position by the cross-section state of the tail sintering ore layer and the flue gas temperature of each wind box. In step 2), if the current sintering end position is determined to be within the normal range, the control device continues to monitor through the tail cross-section visual recognition device and temperature detection device.

In the prior art, since the sintering process is mainly produced by the exhaust operation, there are limitations in controlling the sintering speed (i.e., the downward speed of the combustion zone), resulting in poor control of the sintering speed and difficulty in controlling the sintering endpoint position, which in turn leads to poor sintering ore production effect. In view of this defect, the present invention proposes an upper and lower alternating internal circulation exhaust sintering endpoint control system. When the system reaches the area range of the last 1-3 bellows at the tail of the sintering machine, the system changes the existing continuous bottom exhaust mode to an upper and lower exhaust internal circulation mode at the tail by adding an upper and lower alternating internal circulation exhaust device. The upper and lower alternating internal circulation exhaust device includes an upper exhaust hood arranged on the upper part of the tail sintering trolley, a lower exhaust bellows arranged on the lower part of the tail sintering trolley, and an internal circulation air duct arranged between the upper exhaust hood and the lower exhaust bellows and connecting the two, and a circulating fan is provided on the internal circulation air duct. The present invention improves the device by changing the bottom exhaust into bottom/top up and down adjustable exhaust, and implements internal smoke circulation at the same time. By adjusting the exhaust direction, the direction of smoke circulation is changed, and then the combustion zone in the sintering material layer is changed in the upward and downward moving direction, thereby achieving the purpose of accurately controlling the sintering speed and the sintering end point and improving the production effect of sintered ore.

Preferably, the upper and lower alternating internal circulation exhaust device of the present invention further includes a tail circulation header disposed between the lower exhaust air box and the internal circulation air duct and located at the side of the large flue. The addition of the tail circulation header is conducive to the internal circulation of the tail flue gas without interfering with the operation of the large flue. When the circulating fan is switched forward or reverse, the exhaust direction changes, and the flue gas circulation direction changes accordingly, thereby realizing the change of the upward and downward movement direction of the combustion zone as needed, and further realizing the control of the sintering speed and the sintering end point.

A shutoff valve is provided between the tail circulation header and the main flue, and the two are connected or disconnected through the shutoff valve. One end of the tail circulation header is blocked, and the other end is connected to the main flue of the sintering machine through the shutoff valve. When the shutoff valve is opened, the tail circulation header is part of the main flue, and when the shutoff valve is closed, the tail circulation header is part of the upper and lower alternating internal circulation exhaust device. With such a setting, when the sintering end point is within the normal range, the shutoff valve can be opened, and exhaust sintering is performed according to the conventional exhaust mode. When the sintering end point is not within the normal range, the shutoff valve can be closed. At this time, the upper and lower alternating internal circulation exhaust device can be opened to adjust the exhaust direction, so that the direction of the flue gas circulation is changed, and then the combustion zone in the sintering material layer changes its upward and downward movement direction, thereby regulating the sintering speed and the sintering end point.

In the present invention, an upper exhaust duct pipe is connected between the upper exhaust hood and the inner circulation duct, and a circulation air valve is provided on the upper exhaust duct pipe, which plays a role in real-time regulation of the inner circulation air volume and air pressure.

It is further preferred that the upper and lower alternating internal circulation exhaust device is divided into two parts in the cross-sectional direction of the tail of the sintering machine, namely, it includes two upper exhaust hoods on the left and right (as shown in FIG5 ), each upper exhaust hood is connected to the internal circulation duct through its own upper exhaust flue pipe, and each upper exhaust flue pipe is provided with a circulation air valve. The advantage of such a setting is that the downward speed of the combustion zone in the cross-sectional direction of the sintering machine can be freely adjusted (for example, the sintering speed on the left is fast and the right is slow, then the circulation air valve at the corresponding position can be adjusted to increase the upper exhaust force of the upper exhaust hood on the left part, so that the combustion zone tends to balance). It should be noted that the division into two parts, i.e., setting two upper exhaust hoods on the left and right in the cross-sectional direction of the sintering machine, is only an example cited in the present invention. The present application can also set multiple (for example, 2-6, preferably 2-4) upper exhaust hoods as needed according to parameters such as the width of the sintering machine, i.e., all technical solutions divided into multiple parts to achieve free adjustment of the combustion zone speed are within the protection scope of the present invention.

The upper and lower alternating internal circulation exhaust device can also be equipped with multiple upper exhaust hoods and lower exhaust bellows in the running direction of the sintering machine. The specific position can refer to the normal position of the sintering end point. For example, the general sintering end point is controlled at the second to last bellows, and the sintering end point of a large sintering machine is controlled at the second to last and third bellows.

Specifically speaking of the structure of the upper exhaust hood, it includes a hood side plate and a hood reducer. The hood side plate is arranged on the upper part of the sintering trolley and is softly sealed with the sintering trolley. The hood reducer is arranged on the upper part of the hood side plate and is connected to the upper exhaust flue pipe. When multiple upper exhaust hoods are arranged in the cross-sectional direction of the sintering machine, the upper exhaust hood also includes an inner partition of the hood, which is arranged between two adjacent upper exhaust hoods in the cross-sectional direction of the tail of the sintering machine. The arrangement of the inner partition of the hood can ensure that the upper exhaust hoods in the cross-sectional direction of the sintering machine are closely arranged, thereby ensuring the exhaust efficiency and avoiding air leakage. The lower exhaust bellows is located directly below the sintering trolley and is sealed with the sintering trolley. The lower exhaust bellows is equipped with a bellows branch pipe, the lower part of which is connected to the tail circulation header, and is connected to the upper exhaust hood through the internal circulation air duct, thereby forming a closed-loop internal circulation routing system.

The present invention also adds a tail section visual recognition device downstream of the tail of the sintering machine. The tail section visual recognition device can observe the cross-sectional state of the tail sintering ore layer in real time, and intelligently calculate the current sintering speed of the sintering machine according to the height position of the red layer on the section, and make a judgment on whether the sintering end position is within the normal range. Preferably, the present application also sets a temperature detection device on each bellows at the bottom of the sintering trolley and the bellows branch pipe of the lower exhaust bellows at the tail. The temperature detection device monitors the flue gas temperature of each bellows branch pipe in real time to judge the current sintering end position (the sintering end point in production can also be judged according to the exhaust gas temperature of the last few bellows, and the exhaust gas with the highest temperature is the sintering end point). The present invention also adds a pure oxygen spraying device to the internal circulation air duct, the purpose of which is to increase the pure oxygen medium in the closed-loop internal circulation pipeline system to prevent the internal oxygen content from being insufficient after the flue gas circulates too many times.

The present invention also proposes a control method for using the above-mentioned upper and lower alternating internal circulation exhaust sintering endpoint control system. In this method, after the system is running, the current sintering endpoint position is first determined by visual recognition detection of the tail section and/or temperature detection of each sintering wind box branch pipe. If the endpoint position is not within the normal range, the isolation valve is first closed to allow the sintering machine to enter the tail internal circulation working mode; then, the combustion zone in the sintering material layer is judged to be at the same horizontal height through visual recognition of the tail, if so, enter the processing control process one, if not, enter the processing control process two.

Processing control flow 1: If the current sintering end point is forward, reverse the direction (the exhaust direction is upward exhaust) to run the tail circulation fan, and calculate the power of the tail circulation fan, as shown in formula (1):

W = |(hh ₀ )| × Cp × H × V _machine × λ …… (1);

Then, the fan motor is adjusted according to the calculated tail circulation fan power.

Similarly, if the current sintering endpoint is too far back, the tail circulation fan is run in the forward direction (the exhaust direction is downward exhaust), and the tail circulation fan power is calculated by formula (1). Subsequently, the fan motor is adjusted according to the calculated tail circulation fan power to achieve precise control of the sintering speed and the sintering endpoint, thereby improving the sintering ore production effect.

Processing control flow 2: If the combustion speed of the left side of the current sintering material layer is slow and the circulating fan has been set to reverse mode, then reduce the circulation air valve at the corresponding position of the upper exhaust hood on the left side; if the combustion speed of the left side of the current sintering material layer is slow and the circulating fan has been set to forward mode, then increase the circulation air valve at the corresponding position of the upper exhaust hood on the left side; if the combustion speed of the right side of the current sintering material layer is slow and the circulating fan has been set to reverse mode, then reduce the circulation air valve at the corresponding position of the upper exhaust hood on the right side; if the combustion speed of the right side of the current sintering material layer is slow and the circulating fan has been set to forward mode, then increase the circulation air valve at the corresponding position of the upper exhaust hood on the right side.

After going through two sets of control processes, the system determines whether the current sintering end point position has reached the normal area range. If not, it returns to the link of closing the large flue isolation valve and recalculates the adjustment. If yes, the current adjustment ends.

All formulas in the present invention are obtained by fitting by the inventors based on experiments and engineering applications. All calculations are numerical values converted according to prescribed units, and are obtained by substituting the numerical values after conversion into the formulas (after conversion of the units, only the numerical values are substituted into the formulas for calculation without substituting the units, and the units are only used to adjust the size of the numerical values).

Compared with the prior art, the present invention has the following beneficial technical effects:

1. It can improve the control effect of sintering speed and sintering end point: the present invention changes the existing continuous bottom exhaust mode into an upper and lower exhaust internal circulation mode at the tail of the machine, and changes the bottom exhaust into a bottom/top upper and lower adjustable exhaust by adding an upper and lower alternating internal circulation exhaust device at the tail of the sintering machine. At the same time, the internal circulation of flue gas is implemented, and the direction of flue gas circulation is changed by adjusting the exhaust direction, thereby changing the upward and downward moving direction of the combustion zone in the sintering material layer, thereby achieving the purpose of controlling the sintering speed and the sintering end point and improving the production effect of sintered ore.

2. The sintering speed can be precisely controlled: According to the technology of the present invention, the system can determine in real time whether the current sintering end point position is within the normal range through the machine tail section visual recognition device. If not, the sintering speed of the current sintering machine is immediately adjusted and controlled through the upper and lower alternating internal circulation exhaust device, so that the sintering end point position returns to the normal range, realizing precise control of the sintering speed.

3. The sintering end point position can be finely controlled: Since the present invention can control the sintering speed more effectively than the prior art and can achieve the upward movement of the sintering combustion zone within a certain small range, the sintering end point position can be finely controlled and the combustion zone in the sintering material layer can be ensured to be uniform in the cross-sectional direction of the sintering machine.

In summary, the new technology of the present invention effectively solves the defects and shortcomings of the existing technology without causing other negative effects, and has low investment and operating costs. It can be expected to have high application value in the future market.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of the existing sintering process;

FIG2 is a schematic diagram of a high temperature combustion zone in an existing sintering process;

FIG3 is a schematic structural diagram of a top-to-bottom alternating internal circulation exhaust sintering endpoint control system according to the present invention;

FIG4 is a schematic diagram of the structure of the upper and lower alternating internal circulation exhaust device of the present invention;

FIG5 is a schematic structural diagram of a plurality of upper exhaust hoods arranged in the cross-sectional direction of the tail of the sintering machine in an upper and lower alternating internal circulation exhaust device according to the present invention;

FIG6 is a schematic diagram of a control device in the present invention;

FIG7 is a schematic diagram of the sintering material layer during downward ventilation in the present invention;

FIG8 is a schematic diagram of the sintering material layer during upward ventilation in the present invention;

FIG9 is a schematic diagram of a high temperature combustion zone in the process of the present invention;

FIG10 is a flow chart of a method for controlling an end point of a sintering process with an alternating internal circulation ventilation method according to the present invention;

Wherein: In FIG4 , the rightward arrow on the circulating fan indicates the wind direction when the circulating fan is running in the forward direction, and the leftward arrow indicates the wind direction when the circulating fan is running in the reverse direction.

Reference numerals:

1: sintering trolley; 2: bellows; 3: large flue; 4: upper and lower alternating internal circulation exhaust device; 401: upper exhaust hood; 40101: hood side panel; 40102: hood reducer; 40103: hood inner partition; 402: lower exhaust bellows; 403: internal circulation air duct; 404: circulation fan; 405: tail circulation header; 406: upper exhaust flue pipe; 407: circulation air valve; 5: isolation valve; 6: tail section visual recognition device; 7: pure oxygen injection device; 8: temperature detection device; K: control device.

Detailed ways

The technical solution of the present invention is illustrated below by way of example, and the scope of protection requested by the present invention includes but is not limited to the following embodiments.

According to a first embodiment of the present invention, there is provided a sintering endpoint control system with an upper and lower alternating internal circulation exhaust type.

A sintering endpoint control system with alternating upper and lower internal circulation exhaust type, the system comprises a sintering trolley 1, a bellows 2, and a large flue 3. A plurality of bellows 2 are provided at the lower part of the sintering trolley 1, and the air outlets of each bellows 2 are connected to the large flue 3 at the lower part. The system also comprises an upper and lower alternating internal circulation exhaust device 4 arranged at the tail of the sintering machine. The upper and lower alternating internal circulation exhaust device 4 comprises an upper exhaust hood 401, a lower exhaust bellows 402, an internal circulation air duct 403, and a circulating fan 404. Among them, the upper exhaust hood 401 is arranged at the upper part of the sintering trolley 1 at the tail. The lower exhaust bellows 402 is arranged at the lower part of the sintering trolley 1 at the tail. The upper exhaust hood 401 and the lower exhaust bellows 402 are connected through the internal circulation air duct 403. A circulating fan 404 is arranged on the internal circulation air duct 403.

In the present invention, the upper and lower alternating internal circulation exhaust device 4 further includes a tail circulation header 405 arranged at the lower part of the lower exhaust air box 402. The air outlet of the lower exhaust air box 402 is connected to the tail circulation header 405. The upper exhaust hood 401 is connected to the tail circulation header 405 through the internal circulation air duct 403.

Preferably, the tail circulation header 405 is arranged at the side of the large flue 3. The tail circulation header 405 is connected to the large flue through a cutoff valve 5.

In the present invention, an upper exhaust smoke duct pipe 406 is further connected between the upper exhaust smoke hood 401 and the inner circulation air duct 403. Preferably, a circulation air valve 407 is provided on the upper exhaust smoke duct pipe 406.

Preferably, n upper exhaust hoods 401 are arranged in the cross-sectional direction of the tail of the sintering machine, and each upper exhaust hood 401 is connected to the inner circulation air duct 403 through its own upper exhaust flue pipe 406. The value of n is 2-6, preferably 2-4.

In the present invention, the upper exhaust hood 401 includes a hood side plate 40101, a hood reducer 40102, and a hood inner baffle 40103. The hood side plate 40101 is connected to the sintering trolley 1. The hood reducer 40102 is arranged on the upper part of the hood side plate 40101 and is connected to the upper exhaust flue pipe 406. The hood inner baffle 40103 is arranged between two adjacent upper exhaust hoods 401 in the cross-sectional direction of the tail of the sintering machine.

In the present invention, the system further comprises a tail section visual recognition device 6 arranged downstream of the tail of the sintering machine.

In the present invention, the inner circulation air duct 403 is connected to a pure oxygen spraying device 7 .

In the present invention, the system further comprises a temperature detection device 8. The temperature detection device 8 is provided on each wind box 2 at the lower part of the sintering trolley 1 and the wind box branch pipe of the lower exhaust wind box 402 at the tail.

In the present invention, the system further comprises a control device K. The control device K is connected to and controls the operation of the circulating fan 404 , the circulating air valve 407 , the isolation valve 5 , the tail section visual recognition device 6 , and the temperature detection device 8 .

Example 1

As shown in FIG3 , a sintering endpoint control system with alternating upper and lower internal circulation exhaust type includes a sintering trolley 1, a wind box 2, and a large flue 3. A plurality of wind boxes 2 are provided at the lower part of the sintering trolley 1, and the air outlets of each wind box 2 are connected to the large flue 3 at the lower part. The system also includes an upper and lower alternating internal circulation exhaust device 4 arranged at the tail of the sintering machine. The upper and lower alternating internal circulation exhaust device 4 includes an upper exhaust hood 401, a lower exhaust bellows 402, an internal circulation air duct 403, and a circulating fan 404. Among them, the upper exhaust hood 401 is arranged on the upper part of the sintering trolley 1 at the tail. The lower exhaust bellows 402 is arranged on the lower part of the sintering trolley 1 at the tail. The upper exhaust hood 401 and the lower exhaust bellows 402 are connected through the internal circulation air duct 403. A circulating fan 404 is provided on the internal circulation air duct 403.

Example 2

Example 1 is repeated, except that the upper and lower alternating internal circulation exhaust device 4 further includes a tail circulation header 405 arranged at the lower part of the lower exhaust air box 402. The air outlet of the lower exhaust air box 402 is connected to the tail circulation header 405. The upper exhaust hood 401 is connected to the tail circulation header 405 through the internal circulation duct 403.

Example 3

The second embodiment is repeated, except that the tail circulation header 405 is arranged on the side of the large flue 3. The tail circulation header 405 is connected to the large flue through a cutoff valve 5.

Example 4

Example 3 is repeated, except that an upper exhaust duct pipe 406 is further connected between the upper exhaust hood 401 and the internal circulation air duct 403.

Example 5

As shown in FIG. 4 , Example 4 is repeated except that a circulating air valve 407 is provided on the upper exhaust flue pipe 406 .

Example 6

Example 5 is repeated, except that the system further includes a tail section visual recognition device 6 disposed downstream of the tail of the sintering machine.

Example 7

Example 6 is repeated, except that the inner circulation air duct 403 is connected with a pure oxygen injection device 7.

Example 8

The embodiment 7 is repeated, except that the system further comprises a temperature detection device 8. The temperature detection device 8 is provided on the wind box branch pipes of each wind box 2 at the lower part of the sintering trolley 1 and the lower exhaust wind box 402 at the tail.

Example 9

As shown in FIG6 , Example 8 is repeated, except that the system further includes a control device K. The control device K is connected to and controls the operation of the circulating fan 404 , the circulating air valve 407 , the isolation valve 5 , the tail section visual recognition device 6 , and the temperature detection device 8 .

Example 10

As shown in FIG. 5 , Example 9 is repeated except that two upper exhaust hoods 401 are arranged in the cross-sectional direction of the tail of the sintering machine, and each upper exhaust hood 401 is connected to the inner circulation air duct 403 via its own upper exhaust flue pipe 406 .

Embodiment 11

The embodiment 9 is repeated, except that four upper exhaust hoods 401 are arranged in the cross-sectional direction of the tail of the sintering machine, and each upper exhaust hood 401 is connected to the internal circulation air duct 403 through its own upper exhaust flue pipe 406.

Example 12

The embodiment 10 is repeated, except that the upper exhaust hood 401 comprises a hood side plate 40101, a hood reducer 40102, and a hood inner partition 40103. The hood side plate 40101 is softly sealed and connected to the sintering trolley 1. The hood reducer 40102 is arranged on the upper part of the hood side plate 40101 and is connected to the upper exhaust flue pipe 406. The hood inner partition 40103 is arranged between the two upper exhaust hoods 401 in the cross-sectional direction of the tail of the sintering machine.

Example 13

A method for controlling the end point of sintering by alternating upper and lower internal circulation ventilation, using the system described in Example 9, the method comprising the following steps:

1) The isolation valve 5 is opened, and the system starts to run. The control device K observes the cross section of the sintering ore layer at the tail of the machine in real time through the machine tail cross section visual recognition device 6, and uses this to determine the current sintering end point position.

2) If the current sintering end position is determined to be within the normal range, the control device K continues to monitor through the tail section visual recognition device 6. If the current sintering end position is determined not to be within the normal range, the isolation valve 5 is closed, so that the sintering machine enters the internal circulation working mode.

3) The control device K further determines whether the current sintering end point position is biased forward or backward through the machine tail section visual recognition device 6.

If it is determined that the current sintering end point position is forward, the circulating fan 404 is reversed. If it is determined that the current sintering end point position is backward, the circulating fan 404 is forwarded.

This adjustment ends when the control device K determines that the current sintering end point position has reached the normal range.

Embodiment 14

Repeat Example 13, except that step 1) also includes: the control device K monitors the smoke temperature of each wind box 2 and the lower exhaust wind box 402 in real time through the temperature detection device 8.

At this time, the control device K determines the current sintering end position by the cross-section state of the tail sintering ore layer and the flue gas temperature of each wind box. In step 2), if the current sintering end position is determined to be within the normal range, the control device K continues to monitor through the tail cross-section visual recognition device 6 and the temperature detection device 8.

Embodiment 15

As shown in FIG10 , a method for controlling the sintering endpoint by alternating upper and lower internal circulation ventilation is provided, using the system described in Example 12. The method comprises the following steps:

1) The isolation valve 5 is opened, and the system starts to run. The control device K observes the cross section of the sintering ore layer at the tail of the machine in real time through the machine tail cross section visual recognition device 6, and uses this to determine the current sintering end point position.

2) If it is determined that the current sintering end point position is within the normal range, the control device K continues monitoring through the tail section visual recognition device 6 .

If it is determined that the current sintering end position is not within the normal range, the isolation valve 5 is first closed to make the sintering machine enter the internal circulation working mode. Then, the control device K further determines whether the combustion zone in the material layer is at the same level in the cross-sectional direction of the sintering machine through the machine tail section visual recognition device 6.

3) If it is determined that the combustion zone is at the same horizontal height in the cross-sectional direction of the sintering machine and the current sintering end point position is biased forward, the circulating fan 404 is reversed.

If it is determined that the combustion zone is at the same horizontal height in the cross-sectional direction of the sintering machine and the current sintering end point position is biased to the rear, the circulation fan 404 is operated in the forward direction.

Wherein, the power of the circulating fan 404 is:

W = |(hh ₀ )| × Cp × H × _Vmachine × λ (1).

Where: W is the power of the circulating fan, kW. h is the current sintering end position, m. _h0 is the normal ideal sintering end position, m. _Cp is the volume specific heat capacity of sintered ore, kJ/(m ³ ·℃). H is the width of the sintering trolley, m. _Vmachine is the sintering machine speed, m/min. λ is the power coefficient, λ＝8(kW·℃·min)/kJ.

The motor of the circulation fan 404 is adjusted so that the power of the circulation fan 404 is W.

4) If it is determined that the combustion zone is not at the same horizontal height in the cross-sectional direction of the sintering machine, and at the same time, along the running direction of the sintering trolley 1, the combustion speed of the left side of the sintering material layer is slow and the circulating fan 404 has been set to the reverse mode, then the circulating air valve 407 corresponding to the left upper exhaust hood 401 is adjusted down. Correspondingly, if the combustion speed of the left side of the sintering material layer is slow and the circulating fan 404 has been set to the forward mode, then the circulating air valve 407 corresponding to the left upper exhaust hood 401 is adjusted up.

If it is determined that the combustion zone is not at the same horizontal height in the cross-sectional direction of the sintering machine, and at the same time, along the running direction of the sintering trolley 1, the combustion speed of the right side of the sintering material layer is slow and the circulating fan 404 has been set to the reverse mode, the circulating air valve 407 corresponding to the upper exhaust hood 401 on the right side is adjusted down. Correspondingly, if the combustion speed of the right side of the sintering material layer is slow and the circulating fan 404 has been set to the forward mode, the circulating air valve 407 corresponding to the upper exhaust hood 401 on the right side is adjusted up.

This adjustment ends when the control device K determines that the current sintering end point position has reached the normal range.

Application Example 1

The sintering endpoint is controlled by the method described in Example 15, which comprises the following steps:

1) The isolation valve 5 is opened, and the system starts to run. The control device K observes the cross section of the sintering ore layer at the tail of the machine in real time through the machine tail cross section visual recognition device 6, and uses this to determine the current sintering end point position.

2) Observe the cross-sectional state of the sintering ore layer at the tail of the machine and find that the combustion layer has reached the bottom material, no flames are emitted, and the black ore layer above and the red ore layer below account for about 2/3 and 1/3 respectively, indicating that the current sintering end point position is within the normal range. The control device K continues to monitor through the tail section visual recognition device 6.

Application Example 2

The sintering endpoint is controlled by the method described in Example 15, which comprises the following steps:

1) The isolation valve 5 is opened, and the system starts to run. The control device K observes the cross section of the sintering ore layer at the tail of the machine in real time through the machine tail cross section visual recognition device 6, and uses this to determine the current sintering end point position.

2) Observe the cross-sectional state of the sintering ore layer at the tail of the machine, and find that the black layer becomes thicker and the red ore layer becomes thinner, indicating that the current sintering end position is biased forward. At this time, the isolation valve 5 is first closed to make the sintering machine enter the internal circulation working mode. Then, the control device K further determines whether the combustion zone in the material layer is at the same horizontal height in the cross-sectional direction of the sintering machine through the machine tail section visual recognition device 6.

3) At this time, it is determined that the combustion zone is at the same horizontal height in the cross-sectional direction of the sintering machine, and the current sintering end point position is forward, so the circulation fan 404 is reversed.

Wherein, the power of the circulating fan 404 is:

W = |(hh ₀ )| × Cp × H × _Vmachine × λ = 187.2 kW (1).

Where: W is the power of the circulating fan, kW. h is the current sintering end position, h = 21m. _{h 0} is the normal ideal sintering end position, h ₀ = 24m. C _p is the volume specific heat capacity of sintered ore, C _p = 1.3kJ/(m ³ ·℃). H is the width of the sintering trolley, H = 4m. V _machine is the sintering machine speed, V _machine = 2m/min. λ is the power coefficient, λ = 6(kW·℃·min)/kJ.

The motor of the circulation fan 404 is adjusted so that the power of the circulation fan 404 is W.

Application Example 3

The sintering endpoint is controlled by the method described in Example 15, which comprises the following steps:

1) The isolation valve 5 is opened, and the system starts to run. The control device K observes the cross section of the sintering ore layer at the tail of the machine in real time through the machine tail cross section visual recognition device 6, and uses this to determine the current sintering end point position.

2) Observe the cross-section state of the sintering ore layer at the tail of the machine, and find that there are flames under the red layer and unburned raw materials, indicating that the current sintering end position is too far back. At this time, first close the isolation valve 5 to make the sintering machine enter the internal circulation working mode. Then, the control device K further determines whether the combustion zone in the material layer is at the same horizontal height in the cross-section direction of the sintering machine through the machine tail section visual recognition device 6.

3) At this time, it is determined that the combustion zone is at the same horizontal height in the cross-sectional direction of the sintering machine, and the current sintering end point position is biased to the rear, so the circulating fan 404 is operated in the forward direction.

Wherein, the power of the circulating fan 404 is:

W = |(hh ₀ )| × Cp × H × _Vmachine × λ = 145.6 kW (1).

Where: W is the power of the circulating fan, kW. h is the current sintering end position, h = 26m. _{h 0} is the normal ideal sintering end position, h ₀ = 24m. C _p is the volume specific heat capacity of sintered ore, C _p = 1.3kJ/(m ³ ·℃). H is the width of the sintering trolley, H = 4m. V _machine is the sintering machine speed, V _machine = 2m/min. λ is the power coefficient, λ = 7(kW·℃·min)/kJ.

The motor of the circulation fan 404 is adjusted so that the power of the circulation fan 404 is W.

Application Example 4

The sintering endpoint is controlled by the method described in Example 15, which comprises the following steps:

1) The isolation valve 5 is opened, and the system starts to run. The control device K observes the cross section of the sintering ore layer at the tail of the machine in real time through the machine tail cross section visual recognition device 6, and uses this to determine the current sintering end point position.

2) Observe the cross-sectional state of the sintering ore layer at the tail of the machine, and judge that the current sintering end position is not within the normal range. At this time, first close the isolation valve 5 to make the sintering machine enter the internal circulation working mode. Then, the control device K further judges whether the combustion zone in the material layer is at the same horizontal height in the cross-sectional direction of the sintering machine through the visual recognition device 6 at the tail of the machine.

4) At this time, it is determined that the combustion zone is not at the same horizontal height in the cross-sectional direction of the sintering machine. At the same time, along the running direction of the sintering trolley 1, the combustion speed of the left side of the sintering material layer is slow and the circulating fan 404 has been set to the reverse mode, so the circulating air valve 407 corresponding to the left upper exhaust hood 401 is adjusted down. Until the control device K determines that the current sintering end position has reached the normal range, this adjustment is completed.

Application Example 5

Example 4 is applied repeatedly, except that in step 4), it is determined that the combustion zone is not at the same horizontal height in the cross-sectional direction of the sintering machine. At the same time, along the running direction of the sintering trolley 1, the combustion speed of the left side of the sintering material layer is slow and the circulating fan 404 has been set to the forward mode, so the circulating air valve 407 corresponding to the left upper exhaust hood 401 is adjusted. This adjustment ends until the control device K determines that the current sintering end position has reached the normal range.

Application Example 6

The embodiment 4 is applied repeatedly, except that in step 4), it is determined that the combustion zone is not at the same horizontal height in the cross-sectional direction of the sintering machine. At the same time, along the running direction of the sintering trolley 1, the combustion speed of the right side of the sintering material layer is slow and the circulating fan 404 has been set to the reverse mode, then the circulating air valve 407 corresponding to the upper exhaust hood 401 on the right side is adjusted down. This adjustment ends until the control device K determines that the current sintering end position has reached the normal range.

Application Example 7

The embodiment 4 is applied repeatedly, except that in step 4), it is determined that the combustion zone is not at the same horizontal height in the cross-sectional direction of the sintering machine. At the same time, along the running direction of the sintering trolley 1, the combustion speed of the right side of the sintering material layer is slow and the circulating fan 404 has been set to the forward mode, so the circulating air valve 407 corresponding to the upper exhaust hood 401 on the right side is adjusted. This adjustment ends until the control device K determines that the current sintering end position has reached the normal range.

Claims (11)

1. An up-down alternate internal circulation exhaust type sintering end point control system comprises a sintering trolley (1), an air box (2) and a large flue (3); the lower part of the sintering trolley (1) is provided with a plurality of air boxes (2), and the air outlet of each air box (2) is communicated with a large flue (3) at the lower part; the method is characterized in that: the system also comprises an up-down alternate internal circulation air draft device (4) arranged at the tail of the sintering machine; the upper and lower alternate internal circulation exhaust device (4) comprises an upper exhaust smoke hood (401), a lower exhaust air box (402), an internal circulation air pipe (403) and a circulation fan (404); wherein, the upper exhaust fume hood (401) is arranged at the upper part of the sintering trolley (1) at the tail of the sintering trolley; the lower exhaust bellows (402) is arranged at the lower part of the sintering trolley (1) at the tail of the sintering trolley; the upper exhaust fume hood (401) is communicated with the lower exhaust air box (402) through an internal circulation air pipe (403); the internal circulation air pipe (403) is provided with a circulation fan (404).

2. The sintering end point control system according to claim 1, wherein: the upper and lower alternate internal circulation exhaust device (4) further comprises a tail circulation header (405) arranged at the lower part of the lower exhaust bellows (402); the air outlet of the lower exhaust bellows (402) is communicated with a tail circulation header (405); the upper exhaust fume hood (401) is communicated with the tail circulation header (405) through an inner circulation air pipe (403);

preferably, the tail circulation header (405) is arranged at the side of the large flue (3); the tail circulation header (405) is connected with the large flue through a block valve (5).

3. The sintering end point control system according to claim 1 or 2, characterized in that: an upper exhaust flue pipe (406) is also connected between the upper exhaust fume hood (401) and the inner circulation air pipe (403); preferably, a circulating air valve (407) is arranged on the upper exhaust flue pipe (406).

4. A sintering end point control system according to claim 3, wherein: n upper exhaust fume hoods (401) are arranged in the cross section direction of the sintering machine tail, and each upper exhaust fume hood (401) is connected with an internal circulation air pipe (403) through an upper exhaust flue pipe (406) respectively; wherein: n has a value of 2 to 6, preferably 2 to 4.

5. The sintering end point control system of claim 4, wherein: the upper exhaust fume hood (401) comprises fume hood side plates (40101), fume hood reducer pipes (40102) and fume hood inner partition plates (40103); the smoke hood side plate (40101) is connected with the sintering trolley (1); the fume hood reducing pipe (40102) is arranged at the upper part of the fume hood side plate (40101) and is communicated with the upper air draft flue pipe (406); the inner hood partition plate (40103) is arranged between two upper exhaust hood plates (401) adjacent to each other in the cross section direction of the tail of the sintering machine.

6. The sintering end point control system according to any of claims 1-5, wherein: the system also comprises a tail section visual identification device (6) arranged at the downstream of the sintering machine tail; and/or

The internal circulation air pipe (403) is connected with a pure oxygen spraying device (7); and/or

The system further comprises a temperature detection device (8); temperature detection devices (8) are arranged on the bellows branch pipes of the bellows (2) at the lower part of the sintering trolley (1) and the lower exhaust bellows (402) at the tail.

7. The sintering end point control system according to any of claims 1-6, wherein: the system further comprises a control device (K); the control device (K) is connected with and controls the operation of the circulating fan (404), the circulating air valve (407), the isolating valve (5), the tail section visual identification device (6) and the temperature detection device (8).

8. An up-down alternating inner circulation induced draft type sintering end point control method or an up-down alternating inner circulation induced draft type sintering end point control method using the system according to any one of claims 1 to 7, the method comprising the steps of:

1) Opening a block valve (5), starting the system to run, and observing the section of the tail sintered ore layer in real time by a control device (K) through a tail section visual identification device (6), so as to judge the current sintering end position;

2) If the current sintering end position is judged to be in the normal range, the control device (K) continuously monitors through the tail section visual identification device (6); if the current sintering end position is judged not to be in the normal range, closing the isolating valve (5) to enable the sintering machine to enter an internal circulation working mode;

3) The control device (K) further judges whether the current sintering end point position is front or rear through the tail section visual recognition device (6);

if the current sintering end point position is judged to be front, the circulating fan (404) is reversely operated; if the current sintering end point position is judged to be deviated, the circulating fan (404) is transported forward;

Until the control device (K) judges that the current sintering end point position reaches the normal area range, the adjustment is finished.

9. An up-down alternating inner circulation induced draft type sintering end point control method or an up-down alternating inner circulation induced draft type sintering end point control method using the system according to any one of claims 4 to 7, the method comprising the steps of:

1) Opening a block valve (5), starting the system to run, and observing the section of the tail sintered ore layer in real time by a control device (K) through a tail section visual identification device (6), so as to judge the current sintering end position;

2) If the current sintering end position is judged to be in the normal range, the control device (K) continuously monitors through the tail section visual identification device (6);

If the current sintering end position is judged not to be in the normal range, firstly closing the isolating valve (5) to enable the sintering machine to enter an internal circulation working mode; then, the control device (K) further judges whether the combustion zone in the material layer is at the same horizontal height in the cross section direction of the sintering machine through the tail section visual recognition device (6);

3) If the combustion zone is judged to be at the same horizontal height in the cross section direction of the sintering machine and the current sintering end point position is in front, the circulating fan (404) is reversely operated;

If the combustion zone is judged to be at the same horizontal height in the cross section direction of the sintering machine and the current sintering end point position is deviated, the circulating fan (404) is transported forward;

4) If the combustion zone is judged not to be at the same horizontal height in the cross section direction of the sintering machine, and meanwhile, along the running direction of the sintering trolley (1), the combustion speed of the left side of the sintering material layer is slower, and the circulating fan (404) is set to be in a reverse mode, a circulating air valve (407) corresponding to the exhaust fume hood (401) on the left side is reduced; correspondingly, if the combustion speed of the left side of the sinter bed is slower and the circulating fan (404) is set to be in a forward rotation mode, the circulating air valve (407) corresponding to the exhaust fume hood (401) on the left side is enlarged;

If the combustion zone is judged not to be at the same horizontal height in the cross section direction of the sintering machine, and meanwhile, along the running direction of the sintering trolley (1), the combustion speed on the right side of the sintering material layer is slower, and the circulating fan (404) is set to be in a reverse mode, a circulating air valve (407) corresponding to the exhaust fume hood (401) on the right side is reduced; correspondingly, if the combustion speed of the right side of the sinter bed is slower and the circulating fan (404) is set to be in a forward rotation mode, the circulating air valve (407) corresponding to the exhaust fume hood (401) on the right side is enlarged;

Until the control device (K) judges that the current sintering end point position reaches the normal area range, the adjustment is finished.

10. The sintering end point control method according to claim 8 or 9, characterized in that: in step 3), the power of the circulating fan (404) is as follows:

W＝|(h-h₀)|×Cp×H×V _{Machine for making food} ×λ……(1)；

Wherein: w is the power of a circulating fan, and kW; h is the current sintering end position and m; h ₀ is the normal ideal sintering end position, m; c _p is the volume specific heat capacity of the sintered ore, kJ/(m ³ DEG C); h is the width of the sintering trolley and m; v _{Machine for making food} is the sintering machine speed, m/min; lambda is a power coefficient, and the value range is 5-10 (kW.DEG C.min)/kJ;

the motor of the circulation fan (404) is adjusted so that the power of the circulation fan (404) is W.

11. The sintering end point control method according to any one of claims 8 to 10, characterized in that: the step 1) further comprises: the control device (K) monitors the flue gas temperature of each air box (2) and the lower exhaust air box (402) in real time through the temperature detection device (8);

At this time, in the step 2), if the current sintering end point position is judged to be in the normal range, the control device (K) continuously monitors through the tail section visual recognition device (6) and the temperature detection device (8).