Dust nodulation prevention device and method for scraper type belt type roasting machine

Abstract

The invention belongs to the field of iron and steel smelting, and particularly discloses a dust nodulation prevention device and method for a scraper type belt type roasting machine. The device comprises a roasting machine body, a flue, an air pipe, a combustion chamber, a scraper device and an air speed adjusting device. The air pipe comprises a first pipe section which is obliquely arranged upwards in the airflow flowing direction, a part of dust can be left in the flue or the air pipe through the first pipe section and does not enter the combustion chamber, and meanwhile the scraper device can push the dust at the bottom of the combustion chamber to the roasting machine body through a scraper moving in a reciprocating mode. The air speed adjusting device can adjust the air inlet speed of the combustion chamber, dust in the combustion chamber can be blown away, the dust is blown to the roasting machine body, and therefore dust nodulation is reduced. According to the method, by controlling the air inlet speed of the combustion chamber and the reciprocating motion frequency and vibration frequency of the scraper, dust accumulation in the combustion chamber can be reduced, dust can be fed into the roasting machine body, and therefore dust nodulation in the combustion chamber is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of steel smelting, and particularly relates to a scraper type belt type roaster dust nodulation prevention device and method. BACKGROUND

[0002] Sinter and pellet are two main raw materials for blast furnace ironmaking, respectively. The pollutants and carbon emissions of pellet production process are 60% and 30% lower than those of sintering process, respectively. Therefore, promoting the development of pellet process and increasing the proportion of pellet in blast furnace have become one of the important carbon emission reduction technologies in China's steel industry. Under the background of optimizing blast furnace burden structure, increasing the proportion of pellet and reducing carbon emissions of long process, it is very important to improve the production efficiency of pellet process and reduce energy consumption and carbon emissions.

[0003] When a large proportion of pellets is used in blast furnace smelting, alkaline pellets need to be produced. In the production of alkaline pellets, a large amount of Ca and Mg based additives need to be added to increase the alkalinity. The presence of these additive components can cause the pellets to be easily pulverized during the roasting process, thereby generating a large amount of fine particle powder. These fine particle powders are carried away by the cooling air in the cooling section of the belt roaster and enter the combustion chamber. Since the high-temperature secondary air enters the combustion chamber from the top, the flame of the burner in the combustion chamber is pressed close to the bottom of the combustion chamber by the secondary air. The fine particle powder is decomposed to produce iron sesquioxide under the action of high-temperature roasting, thereby producing nodulation at the bottom of the combustion chamber. If these fine particle powders are not removed in time, the nodulation will accumulate more and more, and in severe cases, it will block the combustion chamber, causing the production of the belt roaster to stop. Therefore, the present application proposes a scraper type belt roaster dust nodulation prevention device and method to reduce the generation of nodulation. SUMMARY

[0004] The main purpose of the present application is to provide a scraper type belt roaster dust nodulation prevention device and method to solve the problem of easy production of nodulation in the combustion chamber of the belt roaster in the prior art, thereby causing the combustion chamber to be blocked.

[0005] To achieve the above technical purpose, the technical scheme adopted by the present application is as follows:

[0006] A scraper type belt roaster dust nodulation prevention device, comprising a roaster body, a flue, an air pipe and a combustion chamber, a plurality of combustion chambers are arranged on the side of the roaster body, and the outlets of the combustion chambers are respectively connected to the side walls of the roaster body. The top of the cooling section of the roaster body is connected to the flue, and the flue is connected to the secondary air inlets of the combustion chambers through a plurality of air pipes.

[0007] The air duct comprises a first pipe section. The first pipe section is arranged upwardly along the flow direction of the air flow. The device further comprises a scraper device and an air speed adjusting device. The scraper device is arranged at the bottom of the combustion chamber for pushing the dust at the bottom of the combustion chamber into the roaster body. The air speed adjusting device is arranged at the air duct for changing the air speed in the air duct, thereby changing the air inlet speed of the combustion chamber.

[0008] Preferably, the flue extends along the length direction of the roaster body. A plurality of the combustion chambers are symmetrically arranged at both sides of the roaster body. A plurality of the air ducts are symmetrically arranged at both sides of the flue. The number of the air ducts is consistent with the number of the combustion chambers, and the air ducts correspond to the combustion chambers one by one, and the air ducts are communicated with the corresponding combustion chambers.

[0009] Preferably, the air duct further comprises a second pipe section. One end of the first pipe section is communicated with the upper part of the flue, and the other end is communicated with one end of the second pipe section. The other end of the second pipe section is communicated with the top of the combustion chamber. The second pipe section is arranged vertically.

[0010] Preferably, the scraper device comprises a first driving device, a shaft coupling, a connecting rod and a scraper. The output end of the first driving device is connected to one end of the connecting rod through the shaft coupling, and the other end of the connecting rod is arranged through the side wall of the combustion chamber and connected to the scraper. The first driving device is used to drive the scraper to reciprocate, so as to push the dust into the roaster body.

[0011] Preferably, the scraper comprises a first plate and a second plate connected to one end of the first plate vertically. The first plate is in sliding contact with the inner bottom wall of the combustion chamber. The side of the second plate away from the first plate is connected to one end of the connecting rod.

[0012] Preferably, the combustion chamber is cylindrical, and the axis of the combustion chamber is perpendicular to the side wall of the roaster body. The first plate is an arc-shaped plate, and the curvature of the first plate is consistent with the curvature of the inner wall of the combustion chamber. The scraper reciprocates along the axis direction of the combustion chamber.

[0013] Preferably, the device further comprises a vibration device. The output end of the vibration device is connected to the first driving device, so as to drive the first driving device to vibrate, thereby driving the scraper to vibrate.

[0014] Preferably, the air speed adjusting device comprises a baffle and a second driving device. A plurality of air vents penetrating the thickness of the baffle are uniformly arranged on the baffle. The baffle is used to extend into the air duct, so as to change the area of the air passage cross section of the air duct, thereby changing the air speed in the air duct. The second driving device drives the baffle to move along the axis direction perpendicular to the pipe section where the baffle is arranged.

[0015] Preferably, the device further includes a dust thickness detection device, which is disposed at the bottom of the combustion chamber.

[0016] A method for preventing dust accumulation in a scraper belt roaster, applied to a dust accumulation prevention device for a scraper belt roaster, the method comprising:

[0017] Step 1: Detect the dust accumulation thickness at two time points with a preset time interval in the combustion chamber using the dust thickness detection device, and calculate the dust accumulation rate.

[0018]

[0019] In the formula, δ is the dust accumulation rate, expressed as the percentage increase in dust thickness at preset time intervals, %. θ1 is the dust accumulation thickness at the first time point, mm. θ2 is the dust accumulation thickness at the second time point, mm. t is the time difference between the second and first time points, h. f is the system adjustment coefficient, h, ranging from 0.8 to 1.2.

[0020] Step 2: Adjust the air intake velocity of the combustion chamber, as well as the reciprocating frequency and vibration frequency of the scraper, according to the dust accumulation rate:

[0021] If δ < δ0, repeat step 1 and the subsequent steps.

[0022] If δ≥δ0, adjust the air intake speed of the combustion chamber, as well as the reciprocating frequency and vibration frequency of the scraper.

[0023] Where δ0 is the limiting dust accumulation rate, %.

[0024] Preferably, adjusting the intake air velocity of the combustion chamber, as well as the reciprocating frequency and vibration frequency of the scraper, includes:

[0025] If δ0≤δ<kδ0, adjust the air intake speed of the combustion chamber.

[0026] If δ≥kδ0, adjust the air intake speed of the combustion chamber, and adjust the reciprocating frequency and vibration frequency of the scraper.

[0027] Where k is the wind speed contribution coefficient, which is dimensionless and ranges from 1.0 to 1.4.

[0028] Preferably, if δ0 ≤ δ < kδ0, adjusting the intake air velocity in the combustion chamber includes:

[0029] Step 1: Calculate the required increase in intake air velocity for the combustion chamber:

[0030]

[0031] In the formula, ν is the required increase in the intake air velocity of the combustion chamber, in m / s. ρ is the dust bulk density, in t / m³. 3 h is the thickness of the roasted pellet bed, mm. d is the pellet diameter, mm. V is the speed of the roasting machine trolley, m / min. a is the system adjustment coefficient, m. 7 / (t·s 2 The value range is 4.8×10⁸-12×10⁸.

[0032] Step 2: Adjust the air intake velocity of the combustion chamber according to the calculation results of Step 1.

[0033] Preferably, if δ≥kδ0, adjusting the intake air velocity of the combustion chamber and adjusting the reciprocating frequency and vibration frequency of the scraper includes:

[0034] Step 1: Calculate the required increase in intake air velocity for the combustion chamber:

[0035]

[0036] Step 2: Calculate the required increase in reciprocating frequency and vibration frequency of the scraper:

[0037]

[0038] In the formula, η 往复 η represents the required increase in reciprocating frequency for the scraper, in times per minute. 振动 Q represents the required increase in vibration frequency for the scraper, in times per minute. 一次 The primary air volume injected into the burner in the combustion chamber, m 3 / h. Q 二次 The volume of secondary air injected into the combustion chamber through the duct, m 3 / h. d 燃烧室 d represents the diameter of the horizontal combustion chamber with blast furnace, in mm. 粉尘 denoted as , where is the average particle size of dust carried by the secondary wind, in mm. b is the system adjustment coefficient, in (times·m) / min. 2 The value range is 15000-30000. c is the system adjustment coefficient, and t ranges from 4.8×10. 7 -7.2×10 7 .

[0039] Step 3: Based on the calculation results of Step 1 and Step 2, adjust the air intake speed of the combustion chamber (3) and adjust the reciprocating frequency and vibration frequency of the scraper (504).

[0040] In the technical solution of this invention, since the first section of the duct is inclined upward along the airflow direction, fine dust particles need to climb along the duct section when passing through it and are blocked by the duct wall, making it difficult for them to pass through. Some fine dust particles are retained in the flue or duct, and these particles do not enter the combustion chamber, which helps reduce dust agglomeration in the combustion chamber. The scraper device can push the dust at the bottom of the combustion chamber into the roaster body through the reciprocating scraper, preventing dust from accumulating at the bottom of the combustion chamber. At the same time, the wind speed regulating device can adjust the air intake speed of the combustion chamber, which helps to disperse the dust in the combustion chamber and blow it into the roaster body, avoiding the high-temperature flame from baking the dust and causing agglomeration. The method disclosed in this invention, by controlling the air intake speed of the combustion chamber, as well as the reciprocating frequency and vibration frequency of the scraper, can reduce dust accumulation in the combustion chamber, which is beneficial for sending the dust into the roaster body, thereby reducing dust agglomeration in the combustion chamber.

[0041] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0042] 1. The dust-prevention device for scraper belt roasters of the present invention reduces the amount of fine dust entering the combustion chamber through the first pipe section of the duct that is inclined, thereby reducing dust accumulation in the combustion chamber. It has a simple structure and low cost.

[0043] 2. The dust-prevention device for the scraper-type belt roaster of the present invention uses a reciprocating scraper to push the dust at the bottom of the combustion chamber to the roaster body. In conjunction with the wind speed adjustment device, the air intake speed of the combustion chamber is adjusted to promote the dust to enter the roaster body, reduce the dust accumulation at the bottom of the combustion chamber, thereby reducing dust nodule formation in the combustion chamber, avoiding combustion chamber blockage, and achieving good anti-nodule effect, which is conducive to improving the operating efficiency of the belt roaster.

[0044] 3. The dust-prevention method for scraper belt roasting machines of the present invention can control the air intake speed of the combustion chamber, as well as the reciprocating motion frequency and vibration frequency of the scraper, thereby reducing dust accumulation at the bottom of the combustion chamber, further improving the effect and efficiency of dust prevention, and facilitating normal production operations. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of the anti-dust and nodule-forming device for a scraper belt roaster according to the present invention.

[0046] Figure 2 This is a schematic diagram showing the connection of the flue, air duct, combustion chamber, and roaster body of the scraper belt roaster anti-dust nodule device of the present invention.

[0047] Figure 3 This is a schematic diagram showing the installation of the drive device and vibration device of the scraper belt roaster anti-dust nodulation device of the present invention.

[0048] Figure 4 This is a schematic diagram showing the connection between the air duct and the combustion chamber of the anti-dust and nodulation device for the scraper belt roaster of the present invention.

[0049] Figure 5 This is a schematic diagram of the wind speed adjustment device of the scraper belt roaster anti-dust nodule device of the present invention.

[0050] Figure 6 This is a schematic flowchart of the method for preventing dust accumulation in a scraper belt roaster according to the present invention.

[0051] Reference numerals in the attached drawings: 1: flue; 2: duct; 201: first pipe section; 202: second pipe section; 3: combustion chamber; 4: burner; 5: scraper device; 501: first drive device; 502: coupling; 503: connecting rod; 504: scraper; 6: wind speed regulating device; 601: baffle plate; 602: vent; 7: roasting machine body; 8: vibration device; 9: support; 10: dust thickness detection device. Detailed Implementation

[0052] The technical solution of the present invention will be illustrated below with examples. The scope of protection sought by the present invention includes, but is not limited to, the following embodiments.

[0053] Please refer to Figures 1 to 6 A dust-prevention device for a scraper belt roaster includes a roaster body 7, a flue 1, air ducts 2, and combustion chambers 3. Several combustion chambers 3 are arranged on the side of the roaster body 7, and the outlet of each combustion chamber 3 is connected to the side wall of the roaster body 7. The top of the cooling section of the roaster body 7 is connected to the flue 1, and the flue 1 is connected to the secondary air inlet of each combustion chamber 3 through several air ducts 2.

[0054] The air duct 2 includes a first duct section 201. The first duct section 201 is inclined upward along the direction of airflow. The device also includes a scraper device 5 and a wind speed regulating device 6. The scraper device 5 is located at the bottom of the combustion chamber 3 to push the dust at the bottom of the combustion chamber 3 into the roaster body 7. The wind speed regulating device 6 is located in the air duct 2 to change the wind speed inside the air duct 2, thereby changing the air intake speed of the combustion chamber 3.

[0055] In the technical solution of this invention, since the first section 201 of the duct 2 is inclined upward along the airflow direction, fine dust particles need to climb along the duct section 201 when passing through it and are blocked by the duct wall, making it difficult for them to pass through. Some fine dust particles will be trapped in the flue 1 or duct 2, and these fine dust particles will not enter the combustion chamber 3, which helps to reduce dust agglomeration in the combustion chamber 3. The scraper device 5 can push the dust at the bottom of the combustion chamber 3 into the roaster body 7 through the reciprocating scraper 504, preventing dust from accumulating at the bottom of the combustion chamber 3. At the same time, the wind speed regulating device 6 can regulate the air intake speed of the combustion chamber 3, which helps to disperse the dust in the combustion chamber 3 and blow the dust into the roaster body 7, avoiding the high temperature flame from baking the dust and causing agglomeration.

[0056] Specifically, the roasting machine body 7 includes eight sequentially connected process sections: a forced-air drying section, a forced-air drying section, a preheating section, a roasting section 1, a roasting section 2, a roasting section 3, a cooling section 1, and a cooling section 2. The pellets are processed sequentially through these sections. In the cooling section 1, cold air blown in from the bottom of the trolley exchanges heat with the high-temperature pellet bed, generating high-temperature exhaust gas of approximately 900°C. The flue 1 connects to the top of the cooling section 1 and transports the high-temperature exhaust gas to each combustion chamber 3 through various ducts 2. The high-temperature exhaust gas not only introduces sensible heat into the combustion chamber 3 but also acts as a combustion aid for the fuel within the combustion chamber 3.

[0057] The combustion chamber 3 is cylindrical (such as a cylinder or square tube), and its axis is perpendicular to the side wall of the calciner body 7. At least one burner 4 is provided in the combustion chamber 3 for injecting flames, and the burner 4 is located on the side wall of the combustion chamber 3. Depending on specific production needs and conditions, the combustion chambers 3 can be located on one or both sides of the calciner body 10. In one embodiment, there are eight combustion chambers 3, symmetrically arranged on both sides of the preheating section, the first calcination section, the second calcination section, and the third calcination section.

[0058] Specifically, the first section 201 of the duct can be directly connected to the flue 1, or it can be connected to the flue 1 through other sections. Furthermore, the flue 1 or the duct 2 is provided with an inspection port for removing trapped dust during maintenance.

[0059] Preferably, the flue 1 extends along the length of the calciner body 7. Several combustion chambers 3 are symmetrically arranged on both sides of the calciner body 7. Several air ducts 2 are symmetrically arranged on both sides of the flue 1. The number of air ducts 2 is the same as the number of combustion chambers 3, and they correspond one-to-one; each air duct 2 connects to its corresponding combustion chamber 3. In one embodiment, there are eight air ducts 2, each connecting the flue 1 to one of the eight combustion chambers 3 located on either side of the preheating section, the first calcination section, the second calcination section, and the third calcination section.

[0060] Preferably, the duct 2 further includes a second duct section 202. One end of the first duct section 201 is connected to the upper part of the flue 1, and the other end is connected to one end of the second duct section 202. The other end of the second duct section 202 is connected to the top of the combustion chamber 3. The second duct section 202 is vertically arranged. The airflow rises along the first duct section 201 and then enters the combustion chamber 3 along the second duct section 202, which can both block some dust and save space.

[0061] Preferably, the scraper device 5 includes a first drive device 501, a coupling 502, a connecting rod 503, and a scraper 504. The output end of the first drive device 501 is connected to one end of the connecting rod 503 via the coupling 502, and the other end of the connecting rod 503 passes through the side wall of the combustion chamber 3 and is connected to the scraper 504. The first drive device 501 is used to drive the scraper 504 to reciprocate, so as to push the dust to the roaster body 7.

[0062] Specifically, the first driving device 501 is one of a cylinder, a hydraulic cylinder, or an electric push rod. The device also includes a bracket 9, which comprises a horizontally arranged support plate and several support columns for supporting the support plate. The first driving device 501 is mounted on the support plate and spaced a certain distance (e.g., 10 cm) from the combustion chamber 3. One end of each support column is fixedly connected to a mounting surface (e.g., the ground), and the other end is fixedly connected to the support plate. In one embodiment, the support plate is rectangular, and there are four support columns, each positioned at one of the four corners of the support plate. To withstand high-temperature environments, the connecting rod 503 can be made of alloy steel.

[0063] Preferably, the scraper 504 includes a first plate and a second plate vertically connected to one end of the first plate. The first plate is in slidable contact with the inner bottom wall of the combustion chamber 3. The side of the second plate opposite to the first plate is connected to one end of the connecting rod 503.

[0064] The dust in combustion chamber 3 mainly accumulates at the bottom. The movement of scraper 504 pushes the dust accumulated at the bottom of combustion chamber 3 into the roasting machine body 7, thereby reducing dust accumulation in combustion chamber 3. The first plate slides and contacts the inner bottom wall of combustion chamber 3, allowing it to agitate the dust pile from the bottom, reducing resistance to pushing the dust, improving pushing efficiency, and preventing dust from entering the gap between the first plate and the inner bottom wall of combustion chamber 3 and causing residue. The second plate is perpendicular to the first plate, ensuring that even if there is a lot of dust at the bottom of combustion chamber 3, it can be pushed into the roasting machine body 7 by the second plate after being agitated by the first plate. To adapt to high-temperature environments, scraper 504 can be made of high-temperature heat-resistant steel.

[0065] Preferably, the combustion chamber 3 is cylindrical, and its axis is perpendicular to the side wall of the roasting machine body 7. The first plate is arc-shaped, and its curvature matches the curvature of the inner wall of the combustion chamber 3. The scraper 504 reciprocates along the axial direction of the combustion chamber 3. The cylindrical shape of the combustion chamber 3 makes it easier for dust to accumulate at the bottom, thus allowing the arc-shaped first plate, which is attached to the bottom wall of the combustion chamber 3, to push the dust to the roasting machine body 7.

[0066] Preferably, the device further includes a vibration device 8. The output end of the vibration device 8 is connected to the first driving device 501 to drive the first driving device 501 to vibrate, thereby driving the scraper 504 to vibrate.

[0067] Specifically, the vibration device 8 is one of an electric vibrator, a pneumatic vibrator, or an inertial vibrator. The output end of the vibration device 8 is connected to the housing of the first drive device 501 to transmit vibration to the scraper 504, thereby shaking off the dust on the scraper 504, preventing dust from adhering and forming nodules on the scraper 504, and promoting the scraper 504 to push the dust to the roasting machine body 7. A buffer pad (such as a rubber pad) is provided between the vibration device 8 and the support plate. At the same time, a through hole is provided on the side wall of the combustion chamber 3 for the connecting rod 503 to pass through. An elastic sealing ring (such as a metal-ceramic composite gasket or a silicon carbide gasket) that can adapt to vibration and high temperature is provided at the through hole. The connecting rod 503 slides through the elastic sealing ring.

[0068] In one embodiment, the vibration device 8 is an electric vibrator, the first driving device 501 is an electric push rod, the output end of the electric vibrator is connected to the reinforcing ring of the electric push rod housing, the electric push rod is fixedly installed on the bracket 9, and the movable end of the electric push rod is coaxially connected to the connecting rod 503 through a coupling.

[0069] Preferably, the wind speed regulating device 6 includes a baffle plate 601 and a second driving device. The baffle plate 601 has a plurality of ventilation openings 602 that penetrate the plate thickness evenly. The baffle plate 601 is used to extend into the air duct 2 to change the area of ​​the ventilation cross-section of the air duct 2, thereby changing the wind speed inside the air duct 2. The second driving device drives the baffle plate 601 to move along a direction perpendicular to the axis of the pipe section where the baffle plate 6 is located.

[0070] The wind deflector 601 is designed to both regulate wind speed and ensure a more even airflow. Specifically, the vent 602 can be rectangular, circular, or rhomboid in shape.

[0071] In one embodiment, the wind speed regulating device 6 is disposed at the second pipe section 202. The second pipe section 202 has an insertion port, and the baffle plate 601 is perpendicular to the axis of the second pipe section 202 and is inserted into the second pipe section 202 through the insertion port. The ventilation opening 602 is rectangular. The second driving device is an electric push rod, which is fixed to the outside of the second pipe section 202, and its movable end is connected to one end of the baffle plate 601. The electric push rod can drive the baffle plate 601 to move in a direction perpendicular to the axis of the second pipe section 202, thereby changing the area of ​​the ventilation cross-section of the second pipe section 202.

[0072] Specifically, the deeper the wind deflector 601 is inserted into the pipe section, the smaller the ventilation cross-sectional area of ​​the pipe section, and the faster the wind speed.

[0073] Preferably, the device further includes a dust thickness detection device 10, which is disposed at the bottom of the combustion chamber 3. In one embodiment, the dust thickness detection device 10 is an ultrasonic dust thickness detector (such as the SONOTEC SONOCHEK series). Dust thickness detectors are existing technology and will not be described in detail here.

[0074] Please refer to Figure 6 A method for preventing dust accumulation in a scraper belt roaster, applied to a dust accumulation prevention device for a scraper belt roaster, the method comprising:

[0075] Step 1: Detect the dust accumulation thickness at two time points in the combustion chamber 3 at a preset time interval (e.g., 1 hour) using the dust thickness detection device 11, and calculate the dust accumulation rate:

[0076]

[0077] In the formula, δ represents the dust accumulation rate, expressed as the percentage increase in dust thickness at preset time intervals, in percentages (%). θ1 represents the dust accumulation thickness at the first time point, in mm. θ2 represents the dust accumulation thickness at the second time point, in mm. t represents the time difference between the second and first time points, in h. f is the system adjustment coefficient, used to unify the units on both sides of the equation, in h, with a value ranging from 0.8 to 1.2.

[0078] Step 2: Adjust the air intake velocity of combustion chamber 3, as well as the reciprocating frequency and vibration frequency of scraper 504, according to the dust accumulation rate.

[0079] If δ < δ0, repeat step 1 and the subsequent steps.

[0080] If δ≥δ0, adjust the air intake speed of combustion chamber 3, as well as the reciprocating frequency and vibration frequency of scraper 504.

[0081] Wherein, δ0 is the limiting dust accumulation rate (this value is related to the maintenance cycle of the factory's baking line; in principle, the longer the maintenance cycle, the greater the allowable limiting dust accumulation rate).

[0082] The method disclosed in this invention reduces dust accumulation in the combustion chamber 3 by controlling the air intake velocity, reciprocating frequency, and vibration frequency of the scraper 504, which facilitates the delivery of dust into the calciner body 7, thereby reducing dust agglomeration in the combustion chamber 3. Specifically, the air intake velocity of the combustion chamber 3 is controlled by the depth of the baffle 601 inserted into the pipe section. The reciprocating frequency of the scraper 504 is controlled by the first drive device 501, and the vibration frequency of the scraper 504 is controlled by the vibration device 8.

[0083] Preferably, adjusting the intake air velocity of the combustion chamber 3, as well as the reciprocating frequency and vibration frequency of the scraper 504, includes:

[0084] If δ0≤δ<kδ0, adjust the air intake speed of combustion chamber 3.

[0085] If δ≥kδ0, adjust the air intake speed of combustion chamber 3, and adjust the reciprocating frequency and vibration frequency of scraper 504.

[0086] Wherein, k is the wind speed contribution coefficient, representing the degree to which adjusting the intake air speed through the wind speed regulating device contributes to reducing dust accumulation. It is dimensionless and ranges from 1.0 to 1.4. Since the adjustment capability of the wind speed regulating device is limited, when δ0 ≤ δ < kδ0, adjusting the intake air speed of the combustion chamber 3 through the wind speed regulating device can contribute to reducing the dust accumulation rate. When δ ≥ kδ0, it is no longer possible to further contribute to reducing the dust accumulation rate by adjusting the intake air speed of the combustion chamber 3 through the wind speed regulating device. In this case, it is necessary to adjust the reciprocating frequency and vibration frequency of the scraper 504 to help reduce the dust accumulation rate.

[0087] Preferably, if δ0≤δ<kδ0, adjusting the intake air velocity in combustion chamber 3 includes:

[0088] Step 1: Calculate the required increase in intake air velocity for combustion chamber 3:

[0089]

[0090] In the formula, ν is the required increase in the intake air velocity of the combustion chamber, in m / s. ρ is the dust bulk density, in t / m³. 3 h is the thickness of the roasted pellet bed, in mm. d is the pellet diameter, in mm. V is the speed of the roasting machine trolley, in m / min. a is the system adjustment coefficient, used to unify the units on both sides of the equation, in m. 7 / (t·s 2The values ​​range from 4.8×10⁸ to 12×10⁸. Among them, the dust bulk density, the thickness of the roasted pellet layer, the pellet diameter, and the speed of the roasting machine trolley were all obtained through on-site testing.

[0091] Step 2: Adjust the air intake speed of combustion chamber 3 according to the calculation results of step 1.

[0092] Specifically, the secondary air inlet of combustion chamber 3 is equipped with an anemometer (such as a POLYTEC LDV series laser Doppler velocimeter) to detect the increased intake air velocity in combustion chamber 3. The air velocity within the pipe section is adjusted by changing the depth of the baffle plate 601 inserted into the pipe section, thereby altering the intake air velocity of combustion chamber 3.

[0093] Preferably, if δ≥kδ0, the intake air velocity of the combustion chamber 3 is adjusted, and the reciprocating frequency and vibration frequency of the scraper 504 are adjusted, including:

[0094] Step 1: Calculate the required increase in intake air velocity for combustion chamber 3:

[0095]

[0096] Step 2: Calculate the required increase in reciprocating frequency and vibration frequency for scraper 504:

[0097]

[0098] In the formula, η 往复 η represents the required increase in reciprocating frequency for the scraper, in times per minute. 振动 Q represents the required increase in vibration frequency for the scraper, in times per minute. 一次 The primary air volume injected into the burner in the combustion chamber, m 3 / h. Q 二次 The volume of secondary air injected into the combustion chamber through the duct, m 3 / h. d 燃烧室 d represents the diameter of the horizontal combustion chamber with blast furnace, in mm. 粉尘 denoted as , where is the average particle size of dust carried by the secondary wind, in mm. b is the system adjustment coefficient, used to unify the units on both sides of the equation, in units of (times·m) / min. 2 The value range is 15000-30000, c is the system adjustment coefficient used to unify the units on both sides of the equation, and t has a value range of 4.8×10. 7 -7.2×10 7 The primary air volume injected into the combustion chamber burner, the secondary air volume injected into the combustion chamber through the air duct, the diameter of the horizontal combustion chamber with baking, and the average particle size of the dust carried by the secondary air were all obtained through on-site testing.

[0099] Step 3: Based on the calculation results of Step 1 and Step 2, adjust the air intake speed of combustion chamber 3, and adjust the reciprocating frequency and vibration frequency of scraper 504.

[0100] Specifically, the device also includes a controller (such as a microcontroller), which is connected to the dust thickness detection device 10, the anemometer, the first drive device 501, the second drive device, and the vibration device 8 via communication (such as Bluetooth connection) for precise control.

[0101] In the above method, when δ0≤δ<kδ0, only the air inlet velocity of combustion chamber 3 is adjusted to make the dust accumulation rate less than the limiting dust accumulation rate. When δ≥kδ0, the air inlet velocity of combustion chamber 3, as well as the reciprocating frequency and vibration frequency of scraper 504, are adjusted simultaneously to make the dust accumulation rate less than the limiting dust accumulation rate.

[0102] It should be noted that all formulas in this invention were obtained by the inventor based on experimental and engineering applications, and all calculations were obtained by substituting the converted values ​​into the formulas after conversion (after conversion, only the values ​​are substituted into the formulas, not the units; the units are only used to adjust the magnitude of the values).

[0103] Example 1

[0104] like Figures 1-6 As shown, a dust-prevention device for a scraper belt calciner includes a calciner body 7, a flue 1, air ducts 2, and combustion chambers 3. Several combustion chambers 3 are arranged on the side of the calciner body 7, and the outlet of each combustion chamber 3 is connected to the side wall of the calciner body 7. The top of the cooling section of the calciner body 7 is connected to the flue 1, and the flue 1 is connected to the secondary air inlet of each combustion chamber 3 through several air ducts 2.

[0105] The air duct 2 includes a first duct section 201. The first duct section 201 is inclined upward along the direction of airflow. The device also includes a scraper device 5 and a wind speed regulating device 6. The scraper device 5 is located at the bottom of the combustion chamber 3 to push the dust at the bottom of the combustion chamber 3 into the roaster body 7. The wind speed regulating device 6 is located in the air duct 2 to change the wind speed inside the air duct 2, thereby changing the air intake speed of the combustion chamber 3.

[0106] The combustion chamber 3 is provided with a burner 4 for injecting flames. There is at least one burner 4, and the burner 4 is located on the side wall of the combustion chamber 3.

[0107] Example 2

[0108] The embodiment 1 is repeated, except that the flue 1 extends along the length of the roasting machine body 7. Several combustion chambers 3 are symmetrically arranged on both sides of the roasting machine body 7. Several air ducts 2 are symmetrically arranged on both sides of the flue 1. The number of air ducts 2 is the same as that of the combustion chambers 3, and they correspond one-to-one. The air ducts 2 are connected to the corresponding combustion chambers 3.

[0109] There are 8 combustion chambers 3, which are symmetrically arranged on both sides of the preheating section, the first roasting section, the second roasting section and the third roasting section. There are 8 air ducts 2, which are connected to the 8 combustion chambers 3 respectively.

[0110] Example 3

[0111] The embodiment 2 is repeated, except that the duct 2 also includes a second duct section 202. One end of the first duct section 201 is connected to the upper part of the flue 1, and the other end is connected to one end of the second duct section 202. The other end of the second duct section 202 is connected to the top of the combustion chamber 3. The second duct section 202 is vertically arranged.

[0112] Example 4

[0113] The embodiment 3 is repeated, except that the scraper device 5 includes a first drive device 501, a coupling 502, a connecting rod 503, and a scraper 504. The output end of the first drive device 501 is connected to one end of the connecting rod 503 via the coupling 502, and the other end of the connecting rod 503 passes through the side wall of the combustion chamber 3 and is connected to the scraper 504. The first drive device 501 is used to drive the scraper 504 to reciprocate, so as to push the dust to the calciner body 7.

[0114] The first driving device 501 is an electric push rod.

[0115] Example 5

[0116] The embodiment 4 is repeated, except that the scraper 504 includes a first plate and a second plate vertically connected to one end of the first plate. The first plate is in slidable contact with the inner bottom wall of the combustion chamber 3. The side of the second plate opposite to the first plate is connected to one end of the connecting rod 503.

[0117] Example 6

[0118] Example 5 is repeated, except that the combustion chamber 3 is cylindrical, and its axis is perpendicular to the side wall of the roasting machine body 7. The first plate is an arc-shaped plate, and its curvature matches the curvature of the inner wall of the combustion chamber 3. The scraper 504 reciprocates along the axial direction of the combustion chamber 3. The cylindrical shape of the combustion chamber 3 makes it easier for dust to accumulate at the bottom, thus, in conjunction with the arc-shaped first plate that fits against the bottom wall of the combustion chamber 3, pushing the dust to the roasting machine body 7.

[0119] Example 7

[0120] The same method is used in embodiment 6, except that the device also includes a vibration device 8. The output end of the vibration device 8 is connected to the first driving device 501 to drive the first driving device 501 to vibrate, thereby driving the scraper 504 to vibrate.

[0121] The vibration device is an electric vibrator.

[0122] Example 8

[0123] The embodiment 7 is repeated, except that the wind speed regulating device 6 includes a baffle plate 601 and a second driving device. The baffle plate 601 has a plurality of ventilation openings 602 that penetrate the plate thickness evenly. The baffle plate 601 is used to extend into the air duct 2 to change the area of ​​the ventilation cross-section of the air duct 2, thereby changing the wind speed inside the air duct 2. The second driving device drives the baffle plate 601 to move along a direction perpendicular to the axis of the pipe section where the baffle plate 6 is located.

[0124] The wind speed regulating device 6 is located at the second pipe section 202. An insertion port is provided on the second pipe section 202, and the baffle plate 601, perpendicular to the axis of the second pipe section 202, is inserted into the second pipe section 202 through the insertion port. The ventilation opening 602 is rectangular. The second driving device is an electric push rod, which is fixed to the outside of the second pipe section 202, and its movable end is connected to one end of the baffle plate 601. The electric push rod can drive the baffle plate 601 to move in a direction perpendicular to the axis of the second pipe section 202.

[0125] Example 9

[0126] The embodiment 8 is repeated, except that the device also includes a dust thickness detection device 10, which is located at the bottom of the combustion chamber 3.

[0127] Among them, the dust thickness detection device 10 is a dust thickness detector.

[0128] Application Example 1

[0129] Taking a 5 million-ton / year belt roasting production line of a large domestic steel plant as an example, the raw material ore is hematite, and the dust bulk density is 2.5 t / m³. 3 The pellet bed thickness of the belt roaster is 400mm, the pellet diameter is 12mm, the trolley speed is 2.5m / min, and there are a total of 32 combustion chambers on both sides of the belt roaster. The primary air volume (air entering from the burner nozzle) of a single combustion chamber is 400m³. 3 / h, the secondary air volume (air entering the combustion chamber from the top secondary air duct) is 9000 m³ / h. 3 / h, dust iron grade is 40%, average particle size of dust carried by secondary air is 0.5mm, diameter of horizontal combustion chamber with baking is 3m, and the production limit dust accumulation rate is set at no more than 10% per hour, then:

[0130] Step 1: The dust accumulation thickness in combustion chamber 3 is measured at two time points with a 1-hour interval (t=1) using dust thickness detection device 11 (measured values: θ1=60mm, θ2=68mm). The system adjustment coefficient f is set to 1 (range 0.8~1.2), and the dust accumulation rate is calculated.

[0131]

[0132] Step 2: Determine the range of dust accumulation rate, with the wind speed contribution coefficient k set to 1.2 (range 1.0 to 1.4).

[0133] Since 13.3% > 10%, δ > δ0, and 13.3% > 12%, i.e., δ > kδ0, the system determines that the intake air speed of combustion chamber 3 needs to be adjusted, and the reciprocating frequency and vibration frequency of scraper 504 need to be adjusted.

[0134] Step 3: Calculate the required increase in intake air velocity for combustion chamber 3, and the required increase in reciprocating frequency and vibration frequency for scraper 504:

[0135] Calculate the required increase in intake air velocity for combustion chamber 3, with the system adjustment coefficient 'a' set to 6 × 10. 8 (Value range 4.8×10) 8 -12×10 8 ):

[0136]

[0137] Calculate the required increase in reciprocating frequency and vibration frequency for scraper 504. The system adjustment coefficient b is set to 20000 (range 15000-30000), and the system adjustment coefficient c is set to 6 × 10⁻⁶. 7 (Value range 4.8×10) 7 -7.2×10 7 ):

[0138]

[0139] Step 4: Based on the calculation results of Step 3, adjust the air intake speed of the combustion chamber 3 by 0.42 m / s through the wind speed adjustment device 6, adjust the reciprocating frequency of the scraper 504 by 11.6 times / minute through the first drive device 501, and adjust the vibration frequency of the scraper 504 by 2.5 times / minute through the vibration device 8.

[0140] Step 5: After the adjustment is completed, return to Step 1 and check the dust accumulation rate. It is found that the dust accumulation rate only increases by 6% per hour, 6% < 13.3%, and 6% < 10%, which proves that the operation is effective and the operation of this cycle is completed.

Claims

1. A dust-prevention device for a scraper belt roaster, comprising a roaster body (7), a flue (1), an air duct (2), and a combustion chamber (3), characterized in that: The roasting machine body (7) has several combustion chambers (3) arranged on its side, and the outlet of each combustion chamber (3) is connected to the side wall of the roasting machine body (7); the top of the cooling section of the roasting machine body (7) is connected to the flue (1), and the flue (1) is connected to the secondary air inlet of each combustion chamber (3) through several air ducts (2); The air duct (2) includes a first pipe section (201); the first pipe section (201) is inclined upward along the flow direction of the airflow; the device also includes a scraper device (5) and a wind speed regulating device (6); the scraper device (5) is located at the bottom of the combustion chamber (3) to push the dust at the bottom of the combustion chamber (3) into the roasting machine body (7); the wind speed regulating device (6) is located in the air duct (2) to change the wind speed in the air duct (2), thereby changing the air intake wind speed of the combustion chamber (3).

2. The anti-dust and anti-nodulation device for scraper belt roasters according to claim 1, characterized in that: The flue (1) extends along the length of the roasting machine body (7); a plurality of combustion chambers (3) are symmetrically arranged on both sides of the roasting machine body (7); a plurality of air ducts (2) are symmetrically arranged on both sides of the flue (1); the number of air ducts (2) is the same as that of the combustion chambers (3), and they correspond one-to-one, and the air ducts (2) are connected to the corresponding combustion chambers (3).

3. The anti-dust and anti-nodulation device for a scraper belt roaster according to any one of claims 1 to 2, characterized in that: The duct (2) further includes a second pipe section (202); one end of the first pipe section (201) is connected to the upper part of the flue (1), and the other end is connected to one end of the second pipe section (202); the other end of the second pipe section (202) is connected to the top of the combustion chamber (3); the second pipe section (202) is vertically arranged.

4. The anti-dust and anti-nodulation device for a scraper belt roaster according to any one of claims 1 to 3, characterized in that: The scraper device (5) includes a first drive device (501), a coupling (502), a connecting rod (503), and a scraper (504); the output end of the first drive device (501) is connected to one end of the connecting rod (503) through the coupling (502), and the other end of the connecting rod (503) passes through the side wall of the combustion chamber (3) and is connected to the scraper (504); the first drive device (501) is used to drive the scraper (504) to reciprocate so as to push the dust to the roasting machine body (7).

5. The anti-dust and anti-nodulation device for a scraper belt roaster according to claim 4, characterized in that: The scraper (504) includes a first plate and a second plate vertically connected to one end of the first plate; the first plate is in sliding contact with the inner bottom wall of the combustion chamber (3); the side of the second plate opposite to the first plate is connected to one end of the connecting rod (503).

6. The anti-dust and anti-nodulation device for a scraper belt roaster according to claim 5, characterized in that: The combustion chamber (3) is cylindrical, and the axis of the combustion chamber (3) is perpendicular to the side wall of the roasting machine body (7); the first plate is an arc plate, and the curvature of the first plate is consistent with the curvature of the inner wall of the combustion chamber (3); the scraper (504) reciprocates along the axial direction of the combustion chamber (3).

7. The anti-dust and anti-nodulation device for a scraper belt roaster according to claim 4, characterized in that: The device also includes a vibration device (8); the output end of the vibration device (8) is connected to the first drive device (501) to drive the first drive device (501) to vibrate, thereby driving the scraper (504) to vibrate.

8. The anti-dust and anti-nodulation device for a scraper belt roaster according to any one of claims 1 to 7, characterized in that: The wind speed regulating device (6) includes a wind deflector (601) and a second driving device; the wind deflector (601) is provided with a plurality of ventilation openings (602) that penetrate the thickness of the plate; the wind deflector (601) is used to extend into the air duct (2) to change the area of ​​the ventilation cross section of the air duct (2), thereby changing the wind speed in the air duct (2); the second driving device drives the wind deflector (601) to move along the axis of the pipe section where the wind deflector (601) is located.

9. The anti-dust and anti-nodulation device for a scraper belt roaster according to any one of claims 1 to 8, characterized in that: The device also includes a dust thickness detection device (10), which is located at the bottom of the combustion chamber (3).

10. A method for preventing dust accumulation in a scraper belt roaster, characterized in that: The method for using the anti-dust and anti-nodulation device for a scraper belt roaster as described in any one of claims 1 to 9 includes: Step 1: The dust accumulation thickness at two time points with a preset time interval in the combustion chamber (3) is detected by the dust thickness detection device (11), and the dust accumulation rate is calculated: In the formula, δ is the dust accumulation rate, expressed as the percentage increase in dust thickness at preset time intervals, %; θ1 is the dust accumulation thickness at the first time point, mm; θ2 is the dust accumulation thickness at the second time point, mm; t is the time difference between the second time point and the first time point, h; f is the system adjustment coefficient, h, with a value range of 0.8 to 1.

2. Step 2: Adjust the air intake speed of the combustion chamber (3), as well as the reciprocating frequency and vibration frequency of the scraper (504), according to the dust accumulation rate: If δ < δ0, repeat step 1 and the subsequent steps; If δ≥δ0, adjust the air intake speed of the combustion chamber (3), as well as the reciprocating frequency and vibration frequency of the scraper (504); Where δ0 is the limiting dust accumulation rate, %.

11. The method according to claim 10, characterized in that: Adjusting the air intake velocity of the combustion chamber (3), as well as the reciprocating frequency and vibration frequency of the scraper (504), includes: If δ0≤δ<kδ0, adjust the air intake speed of the combustion chamber (3); If δ≥kδ0, adjust the air intake speed of the combustion chamber (3) and adjust the reciprocating frequency and vibration frequency of the scraper (504); Where k is the wind speed contribution coefficient, which is dimensionless and ranges from 1.0 to 1.

4.

12. The method according to claim 11, characterized in that: If δ0≤δ<kδ0, adjust the air intake velocity in the combustion chamber (3), including: Step 1: Calculate the required increase in intake air velocity for the combustion chamber (3): In the formula, ν is the required increase in the intake air velocity of the combustion chamber, in m / s; ρ is the dust bulk density, in t / m³. 3 h is the thickness of the roasted pellet bed, mm; d is the pellet diameter, mm; V is the speed of the roasting machine trolley, m / min; a is the system adjustment coefficient, m. 7 / (t·s 2 The value range is 4.8 × 10⁻⁶. 8 -12×10 8 ; Step 2: Adjust the air intake velocity of the combustion chamber (3) according to the calculation results of Step 1.

13. The method according to claim 11, characterized in that: If δ≥kδ0, adjust the air intake speed of the combustion chamber (3) and adjust the reciprocating frequency and vibration frequency of the scraper (504), including: Step 1: Calculate the required increase in intake air velocity for the combustion chamber (3): Step 2: Calculate the required increase in reciprocating frequency and vibration frequency of the scraper (504): In the formula, η 往复 The required reciprocating frequency value for the scraper, times / min; η 振动 The required increase in vibration frequency for the scraper, in times / min; Q 一次 The primary air volume injected into the burner in the combustion chamber, m 3 / h;Q 二次 The volume of secondary air injected into the combustion chamber through the duct, m 3 / h;d 燃烧室 The diameter of the horizontal combustion chamber with baking is in meters (m); d 粉尘 b is the average particle size of dust carried by the secondary wind, in mm; b is the system adjustment coefficient, in (times·m) / min. 2 The value range is 15000-30000; c is the system adjustment coefficient, and t ranges from 4.8×10. 7 -7.2×10 7 ; Step 3: Based on the calculation results of Step 1 and Step 2, adjust the air intake speed of the combustion chamber (3) and adjust the reciprocating frequency and vibration frequency of the scraper (504).

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