CN113883897B - Air channeling prevention system for preheating section of chain grate machine and air flow control method thereof - Google Patents

Abstract

The invention discloses an anti-wind-channeling system for a preheating section of a chain grate machine and a method for controlling wind flow by using the same. The chain grate machine is sequentially provided with a blast drying section, an air draft drying section, a preheating section and a preheating section. The preheating section is communicated with a smoke outlet of the rotary kiln through a first pipeline. And an air channeling prevention device is arranged between the preheating first section and the preheating second section. According to the invention, the movable airflow balance plate is additionally arranged between the PH section and the TPH section of the chain grate machine, and the air pressure of the TPH section is controlled to be more than or equal to that of the PH section by utilizing the position change of the airflow balance plate, so that the problem that the content of NOx in smoke of the TPH section is increased due to the fact that high NOx waste gas of the PH section blows into the TPH section is solved. And the ultralow NOx emission is realized through the accurate regulation and control of the wind flow control method.

Description

A kind of anti-channel air system and air flow control method in preheating section of chain grate machine

technical field

The invention relates to an anti-channeling wind system of a chain grate machine, in particular to an anti-channeling wind system of a preheating section of a chain grate machine and a wind flow control method thereof, belonging to the technical field of flue gas treatment of a chain grate machine.

Background technique

NOx is the main reason for the formation of photochemical smog, acid rain, and haze weather, which aggravates the destruction of the ozone layer and promotes the greenhouse effect, which is harmful to the ecological environment. In 2019, the Ministry of Ecology and Environment issued the "Opinions on Promoting the Implementation of Ultra-Low Emissions in the Iron and Steel Industry", which clearly requires that the hourly average NOx emission concentration of the pellet roasting flue gas is not higher than 50mg/ ^m3 under the condition that the benchmark oxygen content is 18%. . If the oxygen content is higher than 18%, the NOx concentration shall be evaluated according to the value converted to the reference oxygen content. Therefore, it is an effective technical measure to meet the air pollutant emission requirements of iron and steel sintering and pelletizing industry, and at the same time reduce the concentration of NOx and oxygen in the roasting flue gas. Judging from the production conditions of most pellet plants, the NOx emission concentration is generally 100-300 mg/m ³ , and the oxygen content in the exhaust gas is 17%-19%.

The production of NOx in the pellet production process mainly comes from fuel type and thermal type. Although it can be reduced by reducing the output of pellets, that is, reducing the amount of gas or pulverized coal injected, and by reducing the strength requirements of the pellets, that is, reducing the rotary kiln The production of chain grate-rotary kiln pellets can be reduced by adopting lower NOx raw materials and fuels and other measures, but it is difficult to meet the environmental protection requirements of ultra-low emissions.

In the existing technology, due to the lack of systematic research and reliable chain grate machine-rotary kiln pellet production process with low NOx generation and control technology, it has become the norm that the NOx emission in the production process of the pelletizing plant does not meet the standard, which is the biggest challenge facing the enterprise. one. For this reason, enterprises can only reduce the NOx emission by reducing the output of pellets, thereby reducing the amount of gas or pulverized coal injected, reducing the strength requirements of pellets, thereby reducing the temperature of the rotary kiln and using raw materials and fuels with lower NOx. generate. These methods not only affect the production of pellets in terms of output and quality, but also have high requirements on the quality of raw fuels, resulting in increased costs, and cannot fundamentally solve the problem of low-NOx production of pellets.

At present, the preferred NOx removal technology mainly relies on selective catalytic reduction (SCR) and selective non-catalytic reduction (SNCR) technology, which remove NOx at the end and in the process, respectively. For SNCR denitration technology, it is generally considered that the temperature range of 800°C to 1100°C is suitable. SNCR denitrification technology is applied in the production process of chain grate machine-rotary kiln pellets. Usually, reducing agent (ammonia or urea) is sprayed into the flue gas at the second stage of preheating (temperature range 850℃～1100℃) for flue gas denitration. SNCR technology in series with SCR technology is an effective means to achieve ultra-low emission of pellet flue gas. In the face of strong environmental protection pressure, a production system with ultra-low NOx emission from pellet flue gas was proposed (201821480691.X). Through the effective combination of SNCR+SCR double denitration mechanism, chain grate-rotary kiln pellet production can be realized Ultra-low emission of process NOx. However, it is often due to the cross-wind problem caused by the temperature and air pressure difference between the PH section and the TPH section in the chain grate production system, that is, the high NOx exhaust gas in the PH section is crossed to the TPH section, which increases the NOx content in the TPH section flue gas. In turn, it is difficult to achieve precise control of denitrification and standard emission of NOx.

SUMMARY OF THE INVENTION

Aiming at the deficiencies of the prior art, the present invention proposes an anti-channeling wind system in the preheating section of the chain grate machine. To control the air pressure in the TPH section to be greater than or equal to the air pressure in the PH section, so as to prevent the high NOx exhaust gas in the PH section from blowing into the TPH section, causing the NOx content in the TPH section flue gas to increase. Open the airflow balance plate before the airflow of the chain grate anti-channeling system is not balanced, and close it in time after the airflow is stable, which has a positive impact on the chain grate system: that is, only need to perform SNCR+SCR on the exhaust gas in the PH section (about 1/3). The denitration treatment can meet the ultra-low emission requirements of pellet NOx, and the investment and operating costs are greatly reduced. At the same time, by controlling the movement of the airflow balance plate to the TPH end, the bellows of the TPH section close to the PH section is selectively incorporated into the PH section, which prolongs the high temperature preheating time of the pellets and improves the strength of the preheating ball.

To achieve the above object, the technical scheme adopted in the present invention is as follows:

According to the first embodiment of the present invention, there is provided a wind blowing prevention system in the preheating section of a chain grate machine, and the system includes a chain grate machine and a rotary kiln. According to the direction of the material, the chain grate machine is sequentially provided with a blast drying section, a suction drying section, a preheating section and a preheating section. The second preheating section is communicated with the flue gas outlet of the rotary kiln through the first pipe. A blow-by air device is arranged between the preheating first stage and the preheating second stage.

Preferably, the anti-wind blowing device includes an air balance plate, a moving platform, a roller and a slot. The air balance plate is arranged inside the chain grate machine. The moving platforms are arranged on both sides of the outer lower ends of the first stage of preheating and the second stage of preheating. The rollers are arranged at the bottom of the moving platform. The slots are provided on both sides of the outer upper ends of the first stage of preheating and the second stage of preheating. The mobile platform is also provided with a fixed seat. A column is arranged on the fixed seat. The top end of the column is connected with the top end of the airflow balance plate after passing through the slot. A moving motor is also provided outside the moving platform. The moving motor drives the moving platform to move on the rollers. The movement of the mobile platform drives the movement of the fixed seat and the upright column, thereby driving the movement of the airflow balance plate in the chain grate machine.

Preferably, the airflow balance plate is composed of an outer plate and an inner plate. The outer plate is an inner hollow plate body. The inner plate is sleeved in the inner cavity of the outer plate. The inner plate is also connected with the lift motor. The lift motor controls the inner plate to move in the vertical direction of the inner cavity of the outer plate.

Preferably, the system also includes an ammonia agent denitration device. The ammonia agent denitrification device is arranged in the second preheating section and/or the first pipeline.

Preferably, the ammonia agent denitration device includes a first sprayer, a second sprayer and an ammonia agent storage tank. The first sprinkler is arranged in the second preheating section. The second sprinkler is disposed within the first conduit. The ammonia agent storage tank is connected with the first sprayer through a second pipeline. A third pipe branched from the second pipe is connected to the second sprinkler.

Preferably, the system also includes an SCR denitration device and a dust removal device. The air outlet of the second preheating section is connected to the air inlet of the air extraction and drying section through a fourth pipeline. The air outlet of the air extraction and drying section is connected to the chimney through a fifth pipe. The SCR denitration device is arranged on the fourth pipeline. The dust removal device is arranged on the fifth pipe.

Preferably, the system also includes an annular cooler. The annular cooling machine is sequentially provided with a first stage of annular cooling, a second stage of annular cooling and a third stage of annular cooling. The air outlet of the annular cooling section is connected to the air inlet of the rotary kiln through the sixth pipeline. The air outlet of the second ring cooling stage is connected to the air inlet of the preheating stage through the seventh pipeline. The air outlet of the third ring cooling section is connected to the air inlet of the blast drying section through the eighth pipeline. The air outlet of the preheating section is connected to the fifth duct through the ninth duct. The air outlet of the blast drying section is connected to the chimney through the tenth pipe.

Preferably, the system further includes a first pressure detector, a second pressure detector, a first temperature detector, a second temperature detector, a first flow detector, a second flow detector and a flue gas analyzer. The first pressure detector, the first temperature detector and the flue gas analyzer are arranged in the preheating section. The second pressure detector and the second temperature detector are arranged in the second preheating section. The first flow detector is arranged on the seventh pipeline. The second flow detector is arranged on the first pipeline.

According to the second embodiment of the present invention, there is provided a method for controlling air flow in the preheating section of a chain grate machine or a method for controlling air flow using the anti-channeling air system in the preheating section of a chain grate machine according to the first embodiment, the method comprising: Follow the steps below:

1) According to the direction of the material, the green balls enter the chain grate machine, pass through the blast drying section, the exhaust drying section, the preheating section and the preheating section, and then are transported to the rotary kiln for oxidation roasting. The oxidized pellets after oxidative roasting are transported to a ring cooler for cooling.

2) According to the flow direction of hot air, the hot air discharged from the first stage of ring cooling is transported to the rotary kiln through the sixth pipeline, and then transported to the second stage of preheating through the first pipeline. The hot air discharged from the second stage of ring cooling is transported to the first stage of preheating through the seventh pipeline.

3) Adjust the horizontal position of the airflow balance plate set between the first preheating section and the second preheating section, so that the pressure in the first preheating section is greater than or equal to the pressure in the second preheating section.

4) The hot air in the preheating section is finally discharged through the ninth pipe. The hot air in the second stage of preheating is finally discharged through the fourth duct.

Preferably, the method further includes: a first pressure detector is arranged in the preheating section to detect in real time the air pressure in the preheating section as p1, Pa. A first temperature detector is also provided to detect in real time that the gas in the preheating section is stable as c1, K.

Preferably, a second pressure detector is arranged in the second preheating stage to detect the air pressure in the second preheating stage as p2, Pa in real time. A second temperature detector is also provided to detect the gas stability in the second stage of preheating as c2, K in real time.

Preferably, a first flow detector is also provided on the seventh pipeline to detect in real time the gas flow delivered to the first stage of preheating as q1, Nm ³ /h. A second flow detector is arranged on the first pipeline to detect the gas flow delivered to the second preheating section in real time as q2, Nm ³ /h. Then the mass of gas delivered to the preheating section is m1, g:

m1=ρ*q1*t...Formula I.

The mass of gas delivered to the preheating section is m2, g:

m2=ρ*q2*t... Formula II.

In Formula I and Formula II, ρ is the average density of the gas, g/m ³ . t is the gas delivery time, h.

According to the ideal gas equation of state, we get:

p1*v1=ρ*q1*t*R*c1/M... Formula III.

p2*v2=ρ*q2*t*R*c2/M...Formula IV.

In formula III and formula IV, v1 is the volume of the preheating stage, m ³ . v2 is the volume of the second preheating stage, m ³ . R is the gas constant, J/(mol·K). M is the average molar mass of the gas, g/mol.

Preferably, the length of the preheating stage is set as a1, the width as b1, and the height as h1, and the unit is m. Set the length of the second preheating stage as a2, the width as b2, and the height as h2, and the unit is m. but:

v1=k1*a1*b1*h1...Formula V.

v2=k2*a2*b2*h2...Formula VI.

In Formula V and Formula VI, the k1 is the volume correction ratio of the preheating stage. k2 is the volume correction ratio of the second stage of preheating.

Substituting formula V into formula III, we get:

p1=ρ*q1*t*R*c1/(M*k1*a1*b1*h1)...Formula VII.

Substituting formula VI into formula IV, we get:

p2=ρ*q2*t*R*c2/(M*k2*a2*b2*h2)...Formula VII.

Set the horizontal movement of the airflow balance plate to the direction of the preheating section as Δa, m. but:

Z=p1/p2=[q1*c1*k2*(a2-Δa)*b2*h2]/[q2*c2*k1*(a1+Δa)*b1*h1]... Formula VIII.

When Z=1, the minimum amount of movement Δa _min of the airflow balance plate is:

By adjusting the horizontal movement amount Δa of the airflow balance plate to be greater than or equal to the calculated value Δa _min , m of the formula IX, so that Z≥1, that is, p1≥p2.

Preferably, when the horizontal displacement of the airflow balance plate is adjusted to be Δa, it is a step-by-step adjustment, and the number of adjustments is set to N, then:

N=|(p2-p1)/(0.05*p1)|...Formula X.

When the required horizontal displacement of the airflow balance plate is Δa, the number of movements of the airflow balance plate is the calculated value N of the formula X.

Preferably, a flue gas analyzer Y is also provided in the first stage of preheating to detect in real time that the NOx content in the first stage of preheating is less than or equal to 40 mg/m ³ .

In the existing technology, due to the lack of systematic research and reliable chain grate machine-rotary kiln pellet production process with low NOx generation and control technology, the NOx emission in the production process of the pelletizing plant has become the norm, which is the biggest challenge facing the enterprise. one. For this reason, enterprises can only reduce the NOx emission by reducing the output of pellets, thereby reducing the amount of gas or pulverized coal injected, reducing the strength requirements of pellets, thereby reducing the temperature of the rotary kiln and using raw materials and fuels with lower NOx. generate. These methods not only affect the production of pellets in terms of output and quality, but also have high requirements on the quality of raw fuels, resulting in increased costs, and cannot fundamentally solve the problem of low-NOx production of pellets. In addition, by adding a denitrification device after the main exhaust fan, such as the use of selective catalytic reduction (SCR) and non-selective catalytic reduction (SNCR), although the requirements of low NOx emissions can be achieved, due to its investment cost High requirements, high equipment requirements, high energy consumption, high denitration cost and secondary pollution have not been popularized and applied in pelletizing enterprises. At present, the NOx control method of pelletizing plants at home and abroad is mainly realized through process control.

In the existing chain grate machine-rotary kiln pellet production process, the chain grate machine is divided into a blast drying section, an exhaust air drying section, a preheating section and a preheating section. Ring cooling three sections. Among them, the air in the first stage of ring cooling directly enters the rotary kiln to roast the pellets. After the second stage of preheating, the preheated balls are heated and then blown into the draft drying section to dry the green pellets. The air in the second stage of annular cooling enters the preheating stage to heat the preheating balls and then discharges to the outside; the air in the third stage of annular cooling enters the blast drying section to blast and dry the green balls, so as to realize the chain grate. The closed-circuit circulation of the air flow system of the machine-rotary kiln-ring cooler. At the same time, selective non-catalytic reduction technology (SNCR) is used in series with selective catalytic reduction technology (SCR) to remove NOx during the process (in the second stage of preheating) and at the end (after the exhaust port of the second stage of preheating). For example, a production system with ultra-low NOx emission from pellet flue gas (201821480691.X), through the effective combination of SNCR+SCR double denitration mechanism, can achieve ultra-low NOx emission in the production process of chain grate-rotary kiln pellets. However, it is often due to the blow-by problem caused by the temperature and air pressure difference between the PH section and the TPH section in the chain grate machine production system, that is, the high NOx exhaust gas in the PH section crosses the air to the TPH section, which increases the NOx content in the TPH section flue gas. In turn, it is difficult to achieve precise control of denitrification and standard emission of NOx.

In the present invention, in order to solve the problem of cross-wind between the PH section and the TPH section caused by the difference in temperature and air pressure in the production system with ultra-low NOx emission of pellet flue gas, the precise control of denitration and the emission of NOx up to the standard are implemented. A movable airflow balance plate is added between the PH section and the TPH section of the machine, and the position change of the balance plate is used to mainly control the pressure P1 of the TPH section to be greater than or equal to the pressure P2 of the PH section, that is, P1≥P2, to prevent the high NOx exhaust gas in the PH section from flowing to the TPH. Section cross-wind, so that the NOx content in the TPH section flue gas increased. The air flow balance plate of the chain grate machine is opened before the air flow system is not balanced, and it is closed in time after stabilization, which has a positive impact on the chain grate machine system: only SNCR+SCR denitrification treatment is required for the exhaust gas in the PH section (about 1/3) to meet the pelletizing requirements. NOx ultra-low emission requirements, investment and operating costs are greatly reduced; multiple bellows (usually 1-5, which can be reasonably adjusted according to actual working conditions) close to the PH section in the TPH section are selectively incorporated into the PH section, indirectly It prolongs the high temperature preheating time of pellets and improves the strength of the preheating balls.

In the present invention, the air pressure in the preheating stage is detected as p1, Pa in real time by setting the first pressure detector in the preheating stage. A second pressure detector is arranged in the second preheating stage to detect the air pressure in the second preheating stage as p2, Pa in real time. By comparing the detected p1 and p2 values. If the detected p1≥p2, the system does not adjust (the position of the airflow balance plate remains unchanged); if the detected p1<p2, the position of the airflow balance plate is controlled and adjusted to make p1≥p2. In order to prevent the high NOx exhaust gas in the PH section from blowing to the TPH section.

In the present invention, the anti-wind blowing device includes an air balance plate, a moving platform, a roller and a slot. The air balance plate is arranged inside the chain grate machine. The moving platforms are arranged on both sides of the outer lower ends of the first stage of preheating and the second stage of preheating. The rollers are arranged at the bottom of the moving platform. The slots are provided on both sides of the outer upper ends of the first stage of preheating and the second stage of preheating. The mobile platform is also provided with a fixed seat. A column is arranged on the fixed seat. The top end of the upright column is connected to the top end of the airflow balance plate after passing through the slot (the top end of the upright column is transversely bent and then connected to the top end of the air flow balance plate through the slot). A moving motor is also provided outside the moving platform. The moving motor drives the moving platform to move on the rollers. The movement of the mobile platform drives the movement of the fixed seat and the column, which in turn drives the movement of the airflow balance plate in the chain grate machine (moving from the PH section to the TPH section).

Further, the airflow balance plate is composed of an outer plate and an inner plate. The outer plate is an inner hollow plate body. The inner plate is sleeved in the inner cavity of the outer plate. The inner plate is also connected with the lift motor. The lift motor controls the inner plate to move in the vertical direction of the inner cavity of the outer plate. According to the actual needs, adjust the movement of the inner plate, and then change the overall height of the airflow balance plate to meet the needs of different heights and prevent the occurrence of wind channeling.

In the present invention, the thickness of the inner plate is 1-20 cm, preferably 2-15 cm, more preferably 3-10 cm. The thickness of the outer plate (that is, the overall thickness of the airflow balance plate) is 3-25 cm, preferably 5-20 cm, more preferably 8-15 cm. The thickness of the inner cavity of the outer plate is greater than the thickness of the inner plate (for example, the thickness of the inner cavity of the outer plate is 0.5cm, 1cm, 1.5cm, 2cm, etc., which can be selected according to the actual working conditions).

In the present invention, the gas temperature in the first stage of preheating is detected as c1, K in real time by arranging a first temperature detector in the first stage of preheating. A second temperature detector is arranged in the second preheating stage to detect the gas temperature in the second preheating stage as c2, K in real time. The seventh pipeline is also provided with a first flow detector to detect in real time the gas flow delivered to the first stage of preheating as q1, Nm ³ /h. A second flow detector is arranged on the first pipeline to detect the gas flow delivered to the second preheating section in real time as q2, Nm ³ /h. Then it can be calculated that the mass of gas delivered to the preheating section is m1, g:

m1=ρ*q1*t...Formula I.

Further, the gas quality delivered to the preheating section is m2, g:

m2=ρ*q2*t... Formula II.

In Formula I and Formula II, ρ is the average density of the gas, g/m ³ . t is the gas delivery time, h.

According to the ideal gas state equation (pV=nRT=mRT/M), we can get:

p1*v1=ρ*q1*t*R*c1/M... Formula III.

p2*v2=ρ*q2*t*R*c2/M...Formula IV.

In formula III and formula IV, v1 is the volume of the preheating stage, m ³ . v2 is the volume of the second preheating stage, m ³ . R is the gas constant, J/(mol·K). M is the average molar mass of the gas, g/mol.

Preferably, the length of the preheating stage is set as a1, the width as b1, and the height as h1, and the unit is m. Set the length of the second preheating stage as a2, the width as b2, and the height as h2, and the unit is m. but:

v1=k1*a1*b1*h1...Formula V.

v2=k2*a2*b2*h2...Formula VI.

In Formula V and Formula VI, the k1 is the volume correction ratio of the preheating stage. k2 is the volume correction ratio of the second stage of preheating.

In the present invention, when the inner cavity of the first stage of preheating or the second stage of preheating is configured as a regular rectangular body: k1=k2=1. When the cavity configuration of the preheating stage 1 or the preheating stage 2 is an irregular rectangular body, in order to correct the error value of the volume calculation formula (length × width × height), the correction values k1 and k2 are introduced, so that the calculation can obtain The volume is closest to the actual volume. Generally, for the same chain grate, the values of k1 and k2 are fixed constants.

Further, formula V is substituted into formula III, obtains:

p1=ρ*q1*t*R*c1/(M*k1*a1*b1*h1)...Formula VII.

Further, formula VI is substituted into formula IV, obtains:

p2=ρ*q2*t*R*c2/(M*k2*a2*b2*h2)...Formula VII.

When p1<p2, it is necessary to move the airflow balance plate (the initial position of the airflow balance plate is the junction of the preheating stage 1 and the preheating stage 2) so that p1≥p2, and set the horizontal movement of the airflow balance board in the direction of the preheating stage 1 The amount is Δa, m. but:

Z=p1/p2=[q1*c1*k2*(a2-Δa)*b2*h2]/[q2*c2*k1*(a1+Δa)*b1*h1]... Formula VIII.

When Z=1 (that is, p1=p2), the minimum displacement Δa _min of the airflow balance plate is:

By adjusting the horizontal movement amount Δa of the airflow balance plate to be greater than or equal to the calculated value Δa _min , m of the formula IX, so that Z≥1, that is, p1≥p2.

In the present invention, when the horizontal displacement of the airflow balance plate is adjusted to be Δa, it is a step-by-step adjustment, and the adjustment times are set to N, then:

N=|(p2-p1)/(0.05*p1)|...Formula X.

When the required horizontal displacement of the airflow balance plate is Δa, the number of movements of the airflow balance plate is the calculated value N of the formula X.

It should be noted that the △a calculated here cannot be adjusted simply and roughly, but needs to be adjusted slowly, and the changes in real-time parameters are constantly detected during the adjustment process and corrected in time to avoid excessive adjustment steps. Production fluctuates violently and affects product quality indicators. Here you need to set the adjustment step: L=△a/N (take the value of △a as △a _min as an example), and adjust it in N times, N=(p2-p1)/(0.05*p1), N Rounding. Further, the above-mentioned determination of N is a better calculation method, but it is not limited to this method. In principle, the determination of the N value needs to be based on the degree of urgency of adjustment (the less p1 is than p2, the less adjustment times should be, because it is necessary to reduce as soon as possible. Pressure difference). However, a new pressure detection needs to be performed after each adjustment of the step size. If the target is not reached (p1≥p2), it will continue. If the target is reached, stop the adjustment.

Further, a flue gas analyzer is also arranged in the preheating stage to detect in real time that the NOx content in the preheating stage is less than or equal to 40 mg/m ³ . Or, according to the national ultra-low emission standard, the final emission concentration of NOx can be lower than 50mg/m ³ .

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

1. The system of the present invention adds a movable air flow balance plate between the PH section and the TPH section of the chain grate machine, and uses the position change of the balance plate to mainly control the air pressure in the TPH section to be greater than or equal to the air pressure in the PH section to prevent the PH section from being high. The NOx exhaust gas flows to the TPH section, which increases the NOx content in the TPH section flue gas. Effectively reduce the direct emission of pollutants.

2. The chain grate air flow system of the present invention only needs to perform SNCR+SCR denitration treatment on the exhaust gas (about 1/3) of the PH section to meet the ultra-low emission requirements of pellet NOx, and the investment and operation costs are greatly reduced; Part of the bellows near the PH section of the TPH section is selectively incorporated into the PH section, which indirectly prolongs the high temperature preheating time of the pellets and improves the strength of the preheating ball.

3. The system of the present invention is simple in structure, easy to operate, low in cost and investment, has remarkable effect of wind control and emission reduction, and has strong application prospects and greater economic benefits.

4. The air flow control method of the present invention is simple and accurate, and the control process is short. Through real-time data monitoring, a response can be made in a very short time. At the same time, a dynamic fine-tuning can be realized by the way of air flow balance plate edge movement and calculation. , which not only makes the adjustment of the airflow balance plate more scientific and reasonable, but also can effectively avoid the problem that the production quality index is affected by the production fluctuation caused by the excessive adjustment step.

Description of drawings

FIG. 1 is a schematic structural diagram of the anti-channel wind system in the preheating section of the chain grate machine according to the present invention.

FIG. 2 is a schematic structural diagram of the detection mechanism of the anti-channeling wind system in the preheating section of the chain grate machine according to the present invention.

FIG. 3 is a schematic view of the structure of the anti-channel wind device of the present invention.

FIG. 4 is a schematic structural diagram of the airflow balance plate of the present invention.

FIG. 5 is a top view of the structure of the anti-channel wind device of the present invention.

FIG. 6 is a flow chart of the air flow control and adjustment method of the present invention.

Reference numerals: 1: Chain grate machine; 2: Rotary kiln; 3: Anti-channel wind device; 4: Ammonia agent denitration device; 5: SCR denitration device; 6: Dust removal device; Drying section; DDD: ventilation drying section; TPH: preheating section 1; PH: preheating section 2; 301: air balance plate; 30101: outer plate; 30102: inner plate; 30103: lift motor; 302: mobile platform; 30201: Fixed base; 30202: Upright; 30203: Mobile motor; 303: Roller; 304: Slotting; 401: The first sprinkler; 402: The second sprinkler; 403: Ammonia storage tank; C1: Ring cooling section; C2 : second stage of annular cooling; C3: third stage of annular cooling; L1: first pipeline; L2: second pipeline; L3: third pipeline; L4: fourth pipeline; L5: fifth pipeline; L6: sixth pipeline; L7 : seventh pipeline; L8: eighth pipeline; L9: ninth pipeline; L10: tenth pipeline; P1: first pressure detector; P2: second pressure detector; C1: first temperature detector; C2: first pressure detector Two temperature detectors; Q1: first flow detector; Q2: second flow detector; Y: flue gas analyzer.

Detailed ways

The technical solutions of the present invention are illustrated below with examples, and the scope of the claimed protection of the present invention includes but is not limited to the following examples.

According to the first embodiment of the present invention, there is provided a wind blowing prevention system in the preheating section of a chain grate machine, and the system includes a chain grate machine 1 and a rotary kiln 2 . According to the direction of the material, the chain grate machine 1 is sequentially provided with a blast drying section UDD, a suction drying section DDD, a preheating section TPH and a preheating second section PH. The second preheating stage PH is communicated with the flue gas outlet of the rotary kiln 2 through the first pipeline L1. An anti-channel wind device 3 is arranged between the first stage of preheating TPH and the second stage of preheating PH.

Preferably, the anti-wind blowing device 3 includes an airflow balance plate 301 , a moving platform 302 , a roller 303 and a slot 304 . The airflow balance plate 301 is arranged inside the chain grate machine 1 . The moving platform 302 is arranged on both sides of the outer lower ends of the preheating stage PH and the preheating stage 2 PH. The rollers 303 are arranged at the bottom of the moving platform 302 . The slots 304 are provided on both sides of the outer upper ends of the preheating first stage PH and the preheating second stage PH. The mobile platform 302 is also provided with a fixed seat 30201 . A column 30202 is arranged on the fixing seat 30201 . The top of the column 30202 is connected to the top of the airflow balance plate 301 after passing through the slot 304 . A moving motor 30203 is also provided outside the moving platform 302 . The moving motor 30203 drives the moving platform 302 to move on the rollers 303 . The movement of the mobile platform 302 drives the movement of the fixed seat 30201 and the upright column 30202 and further drives the movement of the airflow balance plate 301 in the chain grate machine 1 .

Preferably, the airflow balance plate 301 is composed of an outer plate 30101 and an inner plate 30102. The outer plate 30101 is a hollow plate body. The inner plate 30102 is sleeved in the inner cavity of the outer plate 30101 . The inner plate 30102 is also connected to the lift motor 30103 . The lift motor 30103 controls the inner plate 30102 to move in the vertical direction of the inner cavity of the outer plate 30101 .

Preferably, the system also includes an ammonia agent denitration device 4 . The ammonia agent denitrification device 4 is arranged in the second-stage preheating PH and/or the first pipeline L1.

Preferably, the ammonia agent denitration device 4 includes a first sprayer 401 , a second sprayer 402 and an ammonia agent storage tank 403 . The first sprinkler 401 is arranged in the second stage of preheating PH. The second sprinkler 402 is arranged in the first pipe L1. The ammonia agent storage tank 403 is connected with the first sprayer 401 through the second pipeline L2. A third pipe L3 is branched from the second pipe L2 and is connected to the second sprinkler 402 .

Preferably, the system also includes an SCR denitration device 5 and a dust removal device 6 . The air outlet of the second preheating section PH is connected to the air inlet of the extraction and drying section DDD through the fourth pipeline L4. The air outlet of the air extraction and drying section DDD is communicated to the chimney through the fifth duct L5. The SCR denitration device 5 is arranged on the fourth pipeline L4. The dust removal device 6 is arranged on the fifth pipe L5.

Preferably, the system also includes an annular cooler 7 . The annular cooling machine 7 is sequentially provided with a first stage C1 of annular cooling, a second stage C2 of annular cooling, and a third stage C3 of annular cooling. The air outlet of the ring cooling section C1 is connected to the air inlet of the rotary kiln 2 through the sixth pipeline L6. The air outlet of the second ring cooling stage C2 is connected to the air inlet of the preheating stage TPH through the seventh pipeline L7. The air outlet of the third ring cooling section C3 is connected to the air inlet of the blast drying section UDD through the eighth pipeline L8. The air outlet of the preheating stage TPH is communicated to the fifth duct L5 through the ninth duct L9. The air outlet of the blast drying section UDD is communicated to the chimney through the tenth pipe L10.

Preferably, the system further includes a first pressure detector P1, a second pressure detector P2, a first temperature detector C1, a second temperature detector C2, a first flow detector Q1, a second flow detector Q2 and Flue gas analyzer Y. The first pressure detector P1, the first temperature detector C1 and the flue gas analyzer Y are set in the preheating section of TPH. The second pressure detector P2 and the second temperature detector C2 are arranged in the second stage of preheating PH. The first flow detector Q1 is arranged on the seventh pipeline L7. The second flow detector Q2 is arranged on the first pipeline L1.

According to the second embodiment of the present invention, there is provided a method for controlling air flow in the preheating section of a chain grate machine or a method for controlling air flow using the anti-channeling air system in the preheating section of the chain grate machine according to the first embodiment, the method comprising: Follow the steps below:

1) According to the direction of the material, the green balls enter the chain grate machine 1, pass through the blast drying section UDD, the exhaust drying section DDD, the preheating section TPH and the preheating section PH, and then are transported to the rotary kiln 2 for oxidation roasting. The oxidized pellets after oxidative roasting are sent to the ring cooler 7 for cooling.

2) According to the flow direction of the hot air, the hot air discharged from the first stage C1 of the ring cooling is transported to the rotary kiln 2 through the sixth pipeline L6, and then transported to the second stage PH of the preheating through the first pipeline L1. The hot air discharged from the second stage C2 of ring cooling is transported to the first stage TPH of preheating through the seventh pipeline L7.

3) Adjust the horizontal position of the airflow balance plate 301 between the preheating first stage TPH and the preheating second stage PH, so that the pressure in the preheating first stage TPH is greater than or equal to the pressure in the second preheating stage PH.

4) The hot air in the preheating section of TPH is finally discharged through the ninth duct L9. The hot air in the preheating second stage PH is finally discharged through the fourth duct L4.

Preferably, the method further includes: a first pressure detector P1 is arranged in the preheating first stage TPH to detect the air pressure in the preheating first stage TPH as p1, Pa in real time. A first temperature detector C1 is also provided for real-time detection of the gas temperature in the preheating section of TPH as c1, K.

As a preference, a second pressure detector P2 is arranged in the preheating second stage PH to detect the air pressure in the preheating second stage PH in real time as p2, Pa. A second temperature detector C2 is also provided for real-time detection of the gas temperature in the second stage of preheating PH as c2, K.

Preferably, a first flow detector Q1 is also provided on the seventh pipeline L7 to detect in real time the gas flow delivered to the first stage of preheating TPH as q1, Nm ³ /h. A second flow detector Q2 is arranged on the first pipeline L1 to detect the gas flow delivered to the second preheating stage PH in real time as q2, Nm ³ /h. Then the mass of gas delivered to the preheating section of TPH is m1, g:

m1=ρ*q1*t...Formula I.

The mass of gas delivered to the preheating section of TPH is m2, g:

m2=ρ*q2*t... Formula II.

In Formula I and Formula II, ρ is the average density of the gas, g/m ³ . t is the gas delivery time, h.

According to the ideal gas equation of state, we get:

p1*v1=ρ*q1*t*R*c1/M... Formula III.

P2*v2=ρ*q2*t*R*c2/M...Formula IV.

In Formula III and Formula IV, v1 is the volume of preheated one-stage TPH, m ³ . v2 is the volume of the preheating second stage PH, m ³ . R is the gas constant, J/(mol·K). M is the average molar mass of the gas, g/mol.

Preferably, the length of a preheating stage of TPH is set to be a1, the width to be b1, and the height to be h1, and the units are all m. Set the length of the second preheating stage PH as a2, the width as b2, and the height as h2, and the unit is m. but:

v1=k1*a1*b1*h1...Formula V.

V2=k2*a2*b2*h2...Formula VI.

In Formula V and Formula VI, the k1 is the volume correction ratio of the preheating stage TPH. k2 is the volume correction ratio of the preheating second stage PH.

Substituting formula V into formula III, we get:

p1=ρ*q1*t*R*c1/(M*k1*a1*b1*h1)...Formula VII.

Substituting formula VI into formula IV, we get:

P2=ρ*q2*t*R*c2/(M*k2*a2*b2*h2)...Formula VII.

The horizontal movement amount of the airflow balance plate 301 in the direction of the preheating stage TPH is set as Δa, m. but:

Z=p1/p2=[q1*c1*k2*(a2-Δa)*b2*h2]/[q2*c2*k1*(a1+Δa)*b1*h1]... Formula VIII.

When Z=1, the minimum amount of movement Δa _min of the airflow balance plate 301 is:

By adjusting the horizontal movement amount Δa of the airflow balance plate 301 to be greater than or equal to the calculated value Δa _min ,m of Formula IX, Z≥1, that is, p1≥p2.

Preferably, when the horizontal displacement of the airflow balance plate 301 is adjusted to be Δa, it is a step-by-step adjustment, and the adjustment times are set to N, then:

N=(p2-p1)/(0.05*p1)...Formula X.

When the required horizontal displacement of the airflow balance plate 301 is Δa, the number of movements of the airflow balance plate 301 is the calculated value N of the formula X.

Preferably, a flue gas analyzer Y is also provided in the first stage of preheating TPH to detect in real time that the NOx content in the first stage of preheating TPH is less than or equal to 40 mg/m ³ .

Example 1

As shown in FIG. 1 , an anti-channel wind system in the preheating section of a chain grate machine includes a chain grate machine 1 and a rotary kiln 2 . According to the direction of the material, the chain grate machine 1 is sequentially provided with a blast drying section UDD, a suction drying section DDD, a preheating section TPH and a preheating second section PH. The second preheating stage PH is communicated with the flue gas outlet of the rotary kiln 2 through the first pipeline L1. An anti-channel wind device 3 is arranged between the first stage of preheating TPH and the second stage of preheating PH.

Example 2

Example 1 is repeated, except that the anti-wind blowing device 3 includes an airflow balance plate 301 , a moving platform 302 , a roller 303 and a slot 304 . The airflow balance plate 301 is arranged inside the chain grate machine 1 . The moving platform 302 is arranged on both sides of the outer lower ends of the preheating stage PH and the preheating stage 2 PH. The rollers 303 are arranged at the bottom of the moving platform 302 . The slots 304 are provided on both sides of the outer upper ends of the preheating first stage PH and the preheating second stage PH. The mobile platform 302 is also provided with a fixed seat 30201 . A column 30202 is arranged on the fixing seat 30201 . The top of the column 30202 is connected to the top of the airflow balance plate 301 after passing through the slot 304 . A moving motor 30203 is also provided outside the moving platform 302 . The moving motor 30203 drives the moving platform 302 to move on the rollers 303 . The movement of the mobile platform 302 drives the movement of the fixed seat 30201 and the upright column 30202 and further drives the movement of the airflow balance plate 301 in the chain grate machine 1 .

Example 3

Example 2 is repeated, except that the airflow balance plate 301 is composed of an outer plate 30101 and an inner plate 30102. The outer plate 30101 is a hollow plate body. The inner plate 30102 is sleeved in the inner cavity of the outer plate 30101 . The inner plate 30102 is also connected to the lift motor 30103 . The lift motor 30103 controls the inner plate 30102 to move in the vertical direction of the inner cavity of the outer plate 30101 .

Example 4

Example 3 is repeated except that the system also includes an ammonia agent denitration device 4 . The ammonia agent denitrification device 4 is arranged in the second-stage preheating PH and/or the first pipeline L1.

Example 5

Example 4 is repeated, except that the ammonia agent denitration device 4 includes a first sprayer 401 , a second sprayer 402 and an ammonia agent storage tank 403 . The first sprinkler 401 is arranged in the second stage of preheating PH. The second sprinkler 402 is arranged in the first pipe L1. The ammonia agent storage tank 403 is connected with the first sprayer 401 through the second pipeline L2. A third pipe L3 is branched from the second pipe L2 and is connected to the second sprinkler 402 .

Example 6

Example 5 is repeated, except that the system also includes an SCR denitration device 5 and a dust removal device 6 . The air outlet of the second preheating section PH is connected to the air inlet of the extraction and drying section DDD through the fourth pipeline L4. The air outlet of the air extraction and drying section DDD is communicated to the chimney through the fifth duct L5. The SCR denitration device 5 is arranged on the fourth pipeline L4. The dust removal device 6 is arranged on the fifth pipe L5.

Example 7

Example 6 is repeated except that the system also includes an annular cooler 7 . The annular cooling machine 7 is sequentially provided with a first stage C1 of annular cooling, a second stage C2 of annular cooling, and a third stage C3 of annular cooling. The air outlet of the ring cooling section C1 is connected to the air inlet of the rotary kiln 2 through the sixth pipeline L6. The air outlet of the second ring cooling stage C2 is connected to the air inlet of the preheating stage TPH through the seventh pipeline L7. The air outlet of the third ring cooling section C3 is connected to the air inlet of the blast drying section UDD through the eighth pipeline L8. The air outlet of the preheating stage TPH is communicated to the fifth duct L5 through the ninth duct L9. The air outlet of the blast drying section UDD is communicated to the chimney through the tenth pipe L10.

Example 8

Example 7 is repeated, except that the system further includes a first pressure detector P1, a second pressure detector P2, a first temperature detector C1, a second temperature detector C2, a first flow detector Q1, and a second flow detector Meter Q2 and flue gas analyzer Y. The first pressure detector P1, the first temperature detector C1 and the flue gas analyzer Y are set in the preheating section of TPH. The second pressure detector P2 and the second temperature detector C2 are arranged in the second stage of preheating PH. The first flow detector Q1 is arranged on the seventh pipeline L7. The second flow detector Q2 is arranged on the first pipeline L1.

Method embodiment

Set the length of the preheating section of the chain grate machine as a1 to be 12m, the width to be b1 to be 4.5m, and the height to be h1 to be 3m. Set the length of the preheating second stage PH as a2 is 15m, the width is b2 is 4.5m, and the height is h2 is 3m. The volume correction ratio k1 of the preheating stage of TPH is 1. The volume correction ratio k2 of the preheating second stage PH is 1 (that is, the preheating first stage TPH of the chain grate machine and the preheating second stage PH are both rectangular). When the airflow balance plate 301 is in the initial position (that is, at the junction of the preheating stage of TPH and the preheating stage of PH):

The volume of the preheated one-stage TPH is: v1=1×12×4.5×3=162m ³ .

The volume of the preheating stage of PH is: v2=1×15×4.5×3=202.5m ³ .

It was detected that the gas flow rate q1 delivered to the preheating section TPH was 100Nm ³ /h. It is detected that the gas flow rate q2 delivered to the preheating second stage PH is 150Nm ³ /h. It is detected that the gas temperature in the preheating section of TPH is 858.15K. It is detected that the gas temperature in the PH of the second stage of preheating is 1250.15K.

During the operation of the system, if the air pressure p1 in the first stage of preheating TPH is detected to be -900Pa; the air pressure P2 in the second stage of preheating PH is detected to be -400Pa. Then according to formula VIII and formula IX, carry out the following calculation:

Z=p1/p2=[q1*c1*k2*(a2-Δa)*b2*h2]/[q2*c2*k1*(a1+Δa)*b1*h1]... Formula VIII.

When Z=1, the minimum amount of movement Δa _min of the airflow balance plate 301 is:

which is:

△a _min =(12×4.5×3×1250.15×150-15×4.5×3×858.15×100)/(150×1250.15×4.5×3+100×858.15×4.5×3)=9.47

According to the formula X, the required adjustment times N when the horizontal displacement of the airflow balance plate 301 is Δa=Δa _min :

N=(p2-p1)/(0.05*p1)...Formula X.

which is:

N=丨(-400+900)/(0.05×-900)丨=11.11

When adjusting the airflow balance plate 301 step by step, the single adjustment step is STEP: STEP=△ _amin/ N=9.47/11.11=0.85, and adjust the airflow balance plate 301 according to the calculated value of STEP (adjust from the PH section to the TPH end ), the single adjustment step is 0.85m. After the adjustment is completed, p1 and p2 are detected. If p1≥p2, the adjustment of the airflow balance plate 301 is completed; Plate 301 is adjusted until p1≧p2.

Claims (17)

1. An anti-channeling wind system in the preheating section of a chain grate machine is characterized in that: the system comprises a chain grate machine (1) and a rotary kiln (2); There are blast drying section (UDD), exhaust drying section (DDD), preheating section (TPH) and preheating second section (PH); the preheating second section (PH) passes through the first pipeline (L1) and the rotary kiln (2) The flue gas outlet is communicated; an anti-channel wind device (3) is provided between the first stage of preheating (TPH) and the second stage of preheating (PH); Wherein: the anti-channel wind device (3) comprises an airflow balance plate (301), a moving platform (302), a roller (303) and a slot (304); the airflow balance plate (301) is arranged on the chain grate machine The interior of (1); the moving platform (302) is arranged on both sides of the outer lower ends of the first stage of preheating (TPH) and the second stage of preheating (PH); the rollers (303) are arranged at the bottom of the moving platform (302) ; The slot (304) is provided on both sides of the outer upper end of the first stage of preheating (TPH) and the second stage of preheating (PH); the moving platform (302) is also provided with a fixing seat (30201); the fixing A column (30202) is arranged on the seat (30201); the top end of the column (30202) is connected with the top end of the airflow balance plate (301) after passing through the slot (304); the outside of the mobile platform (302) is also A moving motor (30203) is provided; the moving motor (30203) drives the moving platform (302) to move on the rollers (303); the movement of the moving platform (302) drives the movement of the fixed seat (30201) and the upright column (30202) and further The movement of the airflow balance plate (301) in the chain grate machine (1) is driven. 2. The system according to claim 1, characterized in that: the airflow balance plate (301) is composed of an outer plate (30101) and an inner plate (30102); the outer plate (30101) is an inner hollow plate The inner plate (30102) is sleeved in the inner cavity of the outer plate (30101); the inner plate (30102) is also connected with the lift motor (30103); the lift motor (30103) controls the inner plate (30102) (30101) Move in the vertical direction of the lumen. 3. The system according to claim 2, characterized in that: the system further comprises an ammonia agent denitration device (4); the ammonia agent denitration device (4) is arranged in the second preheating stage (PH) and/or the first Inside a pipeline (L1). The system according to claim 3, characterized in that: the ammonia agent denitration device (4) comprises a first sprayer (401), a second sprayer (402) and an ammonia agent storage tank (403); The first sprayer (401) is arranged in the second preheating stage (PH); the second sprayer (402) is arranged in the first pipeline (L1); the ammonia agent storage tank (403) passes through the first pipe (L1). Two pipes (L2) are connected with the first sprinkler (401); a third pipe (L3) is branched from the second pipe (L2) and connected with the second sprinkler (402). 5. The system according to any one of claims 1-3, characterized in that: the system further comprises an SCR denitration device (5) and a dust removal device (6); The air outlet is connected to the air inlet of the extraction and drying section (DDD) through the fourth pipeline (L4); the air outlet of the extraction and drying section (DDD) is connected to the chimney through the fifth pipeline (L5); the SCR denitration device (5) is arranged on the fourth duct (L4); the dust removal device (6) is arranged on the fifth duct (L5). 6. The system according to claim 4, characterized in that: the system further comprises an SCR denitration device (5) and a dust removal device (6); the air outlet of the second preheating stage (PH) passes through a fourth pipe ( L4) is connected to the air inlet of the extraction and drying section (DDD); the air outlet of the extraction and drying section (DDD) is connected to the chimney through the fifth pipe (L5); the SCR denitration device (5) is arranged in the fourth pipe ( L4); the dust removal device (6) is arranged on the fifth pipe (L5). 7. The system according to any one of claims 1-4, characterized in that: the system further comprises a ring cooler (7); the ring cooler (7) is sequentially provided with a ring cooling section (C1) , the second stage of annular cooling (C2) and the third stage of annular cooling (C3); the air outlet of the first stage of annular cooling (C1) is connected to the air inlet of the rotary kiln (2) through the sixth pipeline (L6); the annular cooling The air outlet of the second stage (C2) is connected to the air inlet of the preheating first stage (TPH) through the seventh duct (L7); the air outlet of the third annular cooling stage (C3) is connected to the blast through the eighth duct (L8). The air inlet of the drying section (UDD); the air outlet of the preheating section (TPH) is connected to the fifth duct (L5) through the ninth duct (L9); the air outlet of the blast drying section (UDD) passes through the Ten pipes (L10) are connected to the chimney. 8. The system according to claim 5, characterized in that: the system further comprises an annular cooling machine (7); the annular cooling machine (7) is sequentially provided with a first stage of annular cooling (C1) and a second stage of annular cooling (C1) C2) and the third stage of annular cooling (C3); the air outlet of the first stage of annular cooling (C1) is connected to the air inlet of the rotary kiln (2) through the sixth pipeline (L6); the air outlet of the second stage of annular cooling (C2) is connected to the air inlet of the rotary kiln (2). The air outlet is connected to the air inlet of the preheating section (TPH) through the seventh duct (L7); the air outlet of the third annular cooling section (C3) is communicated to the air blasting and drying section (UDD) through the eighth duct (L8). air inlet; the air outlet of the preheating section (TPH) is connected to the fifth duct (L5) through the ninth duct (L9); the air outlet of the blast drying section (UDD) is communicated through the tenth duct (L10) to the chimney. 9. The system according to claim 6, characterized in that: the system further comprises an annular cooling machine (7); the annular cooling machine (7) is sequentially provided with a first stage of annular cooling (C1) and a second stage of annular cooling (C1) C2) and the third stage of annular cooling (C3); the air outlet of the first stage of annular cooling (C1) is connected to the air inlet of the rotary kiln (2) through the sixth pipeline (L6); the air outlet of the second stage of annular cooling (C2) is connected to the air inlet of the rotary kiln (2). The air outlet is connected to the air inlet of the preheating section (TPH) through the seventh duct (L7); the air outlet of the third annular cooling section (C3) is communicated to the air blasting and drying section (UDD) through the eighth duct (L8). air inlet; the air outlet of the preheating section (TPH) is connected to the fifth duct (L5) through the ninth duct (L9); the air outlet of the blast drying section (UDD) is communicated through the tenth duct (L10) to the chimney. 10. The system according to claim 7, characterized in that: the system further comprises a first pressure detector (P1), a second pressure detector (P2), a first temperature detector (C1), a second temperature detector A detector (C2), a first flow detector (Q1), a second flow detector (Q2), and a flue gas analyzer (Y); the first pressure detector (P1), the first temperature detector (C1) ) and the flue gas analyzer (Y) are arranged in the first stage of preheating (TPH); the second pressure detector (P2) and the second temperature detector (C2) are arranged in the second stage of preheating (PH); The first flow detector (Q1) is arranged on the seventh pipeline (L7); the second flow detector (Q2) is arranged on the first pipeline (L1). 11. The system according to claim 8, characterized in that: the system further comprises a first pressure detector (P1), a second pressure detector (P2), a first temperature detector (C1), a second temperature detector A detector (C2), a first flow detector (Q1), a second flow detector (Q2), and a flue gas analyzer (Y); the first pressure detector (P1), the first temperature detector (C1) ) and the flue gas analyzer (Y) are arranged in the first stage of preheating (TPH); the second pressure detector (P2) and the second temperature detector (C2) are arranged in the second stage of preheating (PH); The first flow detector (Q1) is arranged on the seventh pipeline (L7); the second flow detector (Q2) is arranged on the first pipeline (L1). 12. The system according to claim 9, characterized in that: the system further comprises a first pressure detector (P1), a second pressure detector (P2), a first temperature detector (C1), a second temperature detector A detector (C2), a first flow detector (Q1), a second flow detector (Q2), and a flue gas analyzer (Y); the first pressure detector (P1), the first temperature detector (C1) ) and the flue gas analyzer (Y) are arranged in the first stage of preheating (TPH); the second pressure detector (P2) and the second temperature detector (C2) are arranged in the second stage of preheating (PH); The first flow detector (Q1) is arranged on the seventh pipeline (L7); the second flow detector (Q2) is arranged on the first pipeline (L1). 13. A method for air flow control using the anti-channeling wind system in the preheating section of the chain grate machine as claimed in claim 12, wherein the method comprises the following steps: 1) According to the direction of the material, the raw balls enter the chain grate machine (1), and then pass through the blast drying section (UDD), the exhaust drying section (DDD), the first stage of preheating (TPH) and the second stage of preheating (PH) and then conveyed. Carry out oxidative roasting in the rotary kiln (2); the oxidized pellets after the oxidative roasting is completed are transported to the ring cooler (7) for cooling; 2) According to the flow direction of the hot air, the hot air discharged from the first stage (C1) of the ring cooling is transported to the rotary kiln (2) through the sixth pipeline (L6), and then transported to the second preheating stage (PH) through the first pipeline (L1) Inside; the hot air discharged from the second stage of ring cooling (C2) is transported to the first stage of preheating (TPH) through the seventh pipeline (L7); 3) Adjust the horizontal position of the airflow balance plate (301) set between the preheating first stage (TPH) and the preheating second stage (PH), so that the pressure in the preheating first stage (TPH) is greater than or equal to the preheating second stage ( PH) pressure; 4) The hot air in the first stage of preheating (TPH) is finally discharged through the ninth pipe (L9); the hot air in the second stage of preheating (PH) is finally discharged through the fourth pipe (L4). 14. The method according to claim 13, characterized in that: the method further comprises: a first pressure detector (P1) is arranged in the preheating stage (TPH) to detect the air pressure in the preheating stage (TPH) in real time as p1, Pa; also provided with a first temperature detector (C1) real-time detection of the gas temperature in the preheating section (TPH) is c1, K; A second pressure detector (P2) is arranged in the second preheating stage (PH) to detect the air pressure in the second preheating stage (PH) in real time as p2, Pa; a second temperature detector (C2) is also arranged to detect the preheating pressure in real time. The gas temperature in the second hot stage (PH) is c2, K; A first flow detector (Q1) is also provided on the seventh pipeline (L7) to detect in real time the gas flow delivered to the first stage of preheating (TPH) as q1, Nm ³ /h; set on the first pipeline (L1) There is a second flow detector (Q2) for real-time detection of the gas flow delivered to the second preheating stage (PH) as q2, Nm ³ /h; then the gas mass delivered to the first stage of preheating (TPH) is m1, g: m1=ρ*q1*t... formula I; The mass of gas delivered to the preheating section (TPH) is m2, g: m2=ρ*q2*t... formula II; In Formula I and Formula II, ρ is the average density of the gas, g/m ³ ; t is the gas delivery time, h; According to the ideal gas equation of state, we get: p1*v1=ρ*q1*t*R*c1/M... Formula III; p2*v2=ρ*q2*t*R*c2/M... Formula IV; In Formula III and Formula IV, v1 is the volume of the first stage of preheating (TPH), m ³ ; v2 is the volume of the second stage of preheating (PH), m ³ ; R is the gas constant, J/(mol·K); M is the average molar mass of the gas, g/mol. 15. The method according to claim 14, characterized in that: the length of the first stage of preheating (TPH) is set as a1, the width is b1, the height is h1, and the unit is m; the second stage of preheating (PH) is set as The length is a2, the width is b2, the height is h2, and the unit is m; then: v1=k1*a1*b1*h1...Formula V; v2=k2*a2*b2*h2...Formula VI; In Formula V and Formula VI, the k1 is the volume correction ratio of the first stage of preheating (TPH); k2 is the volume correction ratio of the second stage of preheating (PH); Substituting formula V into formula III, we get: p1=ρ*q1*t*R*c1/(M*k1*a1*b1*h1)...Formula VII; Substituting formula VI into formula IV, we get: p2=ρ*q2*t*R*c2/(M*k2*a2*b2*h2)... formula VII; Set the horizontal movement amount of the airflow balance plate (301) to the preheating stage (TPH) direction as Δa, m; then: Z=p1/p2=[q1*c1*k2*(a2-△a)*b2*h2]/[q2*c2*k1*(a1+△a)*b1*h1]...Formula VIII; When Z=1, the minimum amount of movement Δa _min of the airflow balance plate (301) is:

By adjusting the horizontal movement amount Δa of the airflow balance plate (301) to be greater than or equal to the calculated value Δa _min ,m of formula IX, Z≥1, that is, p1≥p2. 16. The method according to claim 15, characterized in that: adjusting the horizontal displacement of the airflow balance plate (301) to be Δa is a step-by-step adjustment, and the number of adjustments is set to N, then: N=|(p2-p1)/(0.05*p1)|...Formula X; When the required horizontal displacement of the airflow balance plate (301) is Δa, the number of movements of the airflow balance plate (301) is the calculated value N of the formula X. 17. The method according to claim 16, characterized in that: a flue gas analyzer (Y) is also provided in the preheating section (TPH) to detect the NOx content in the preheating section (TPH) in real time and is less than or equal to 40mg/ m ³ .

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