Device for retarding ring formation of rotary kiln by utilizing sound waves

Abstract

The invention relates to a device for retarding ring formation of a rotary kiln by using sound waves. The device comprises sound wave generating equipment and a thermal infrared imager, the sound wave generating devices are evenly distributed on the upper side, the lower side, the left side and the right side of the outer wall of the rotary kiln wall in the axial direction. The thermal infrared imager is arranged on one side of the outer wall of the kiln wall of the rotary kiln in the axial direction. According to the sound wave transmission principle, particles on the inner wall of the rotary kiln are oscillated through low-frequency and high-energy sound waves, binding force between ash particles and the inner wall of the rotary kiln is destroyed, the particles deposited on the surface of the inner wall fall off, and therefore the ring forming phenomenon of the rotary kiln is effectively relieved.

Description

Technical Field

[0001] The present invention relates to the technical field of iron ore pellet processing, and particularly to a device for using sound waves to slow down the ring formation in a rotary kiln. Background Art

[0002] Pellet ore is one of the main burden materials for blast furnace ironmaking. In recent years, the pelletizing method has attracted people's attention in the field of iron ore agglomeration due to its advantages such as low energy consumption, small emissions, and high iron grade.

[0003] Most pellet production in China adopts the grate-kiln method. This method has the advantages of uniform roasting, large-scale equipment, high single-unit production capacity, strong operation flexibility, and strong raw material adaptability, meeting the production needs of Chinese steel enterprises.

[0004] However, the rotary kiln used for roasting is prone to ring formation during operation. This phenomenon will damage the kiln lining and affect the quality of the finished pellet ore, bringing great difficulties to pellet production. When there is too much ring material, it will cause production reduction, shutdown, and even more serious safety accidents. In steel enterprises, the ring formation is generally treated once every two months, which not only reduces the working efficiency of the grate-kiln, affects the pellet output, but also increases the process energy consumption, damages the refractory material of the furnace lining. Generally, for each minor ring formation treatment, the thickness of the refractory material is generally reduced by 10 - 15 mm, bringing adverse effects to pellet production. Therefore, both laboratory personnel and front-line production personnel have carried out a lot of work on pellet ring formation to try to control the ring formation in the rotary kiln to extend its service life. Summary of the Invention

[0005] Aiming at the above problems, the purpose of the present invention is to provide a device for using sound waves to slow down the ring formation in a rotary kiln. By using the principle of sound wave transmission and vibration, through low-frequency and high-energy sound waves, the particles on the inner wall of the rotary kiln are caused to vibrate, so that the particles deposited on the inner wall surface of the rotary kiln fall off, thereby alleviating the ring formation phenomenon in the rotary kiln.

[0006] The technical solution adopted by the present invention is as follows:

[0007] A device for using sound waves to slow down the ring formation in a rotary kiln proposed by the present invention includes a sound wave generating device and a thermal infrared imager; the sound wave generating devices are evenly distributed along the axial direction on the upper side, lower side, left side, and right side of the outer wall of the rotary kiln wall; the thermal infrared imager is arranged along the axial direction on one side of the outer wall of the rotary kiln wall.

[0008] Further, the sound wave generating device includes a sound wave generator and a sound guide tube; the output end of the sound wave generator is closely attached to the outer wall of the rotary kiln through the sound guide tube.

[0009] Further, the parameters of the acoustic wave generator are as follows: frequency 40 - 70 HZ, sound pressure level 90 - 129 DB, compressed air flow rate 1 - 5 m 3 / mm, and pressure 0.1 - 0.5 MPa.

[0010] Further, a composite sound insulation cover is provided outside the acoustic wave generating device.

[0011] Further, the composite sound insulation cover includes an aluminum foil layer, a ceramic fiber layer, and a stainless steel layer; the ceramic fiber layer is correspondingly arranged outside the aluminum foil layer; the stainless steel layer is correspondingly arranged outside the ceramic fiber layer; the composite sound insulation cover correspondingly wraps outside the acoustic wave generating device, and its inner end is closely attached to the outer wall of the kiln wall of the rotary kiln.

[0012] Further, the frequency and sound pressure level of the acoustic wave generator on the outer wall of the rotary kiln wall gradually decrease with its position height.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] 1. The present invention utilizes the principle of acoustic wave transmission. Through low-frequency and high-energy acoustic waves, the particles on the inner wall of the rotary kiln are oscillated, the binding force between the ash particles and the inner wall of the rotary kiln is destroyed, and the particles deposited on the inner wall surface fall off, thereby effectively alleviating the phenomenon of ring formation in the rotary kiln.

[0015] 2. The present invention can be effectively used in combination with various traditional ring formation alleviation schemes to give full play to their respective advantages.

[0016] 3. Compared with the traditional scheme, the present invention does not need to change the raw material composition, thermal system, and fuel injection, can completely retain the original production mode, and will not cause large fluctuations to the original production. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic side sectional structure view of the present invention;

[0018] Figure 2 is Figure 1 the schematic relative position view between a single acoustic wave generator and the rotary kiln wall in

[0019] Figure 3 is a schematic front sectional structure view of the present invention.

[0020] Among them, reference numerals: 1 - acoustic wave generator; 2 - sound duct; 3 - kiln wall; 4 - aluminum foil layer; 5 - ceramic fiber layer; 6 - stainless steel layer; 7 - burner; 8 - thermal infrared imager. DETAILED DESCRIPTION OF THE INVENTION

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or in the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0022] It should be noted that in the description of the present invention, the orientation or positional relationship indicated by the terms "upper", "lower", "top", "bottom", "one side", "the other side", "left", "right", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating that the device or element must have a specific orientation, be constructed and operated in a specific orientation.

[0023] See the attached Figures 1 - 3 , which gives the specific structure of an embodiment of a device for using sound waves to slow down the ring formation in a rotary kiln proposed by the present invention. The device includes a sound wave generating device and a thermal infrared imager 8. In this embodiment, the sound wave generating devices are evenly distributed along the axial direction on the upper side, lower side, left side and right side of the outer wall of the rotary kiln wall 3. That is, there are four groups of sound wave generating devices evenly distributed circumferentially on the outer wall of the kiln wall 3, and the distance between each group is 5 - 8m; the thermal infrared imager 8 is arranged along the axial direction on one side of the outer wall of the rotary kiln wall 3 for photographing the rotary kiln and monitoring the ring formation situation.

[0024] Among them, the sound wave generating device includes a sound wave generator 1 and a sound guide tube 2; the output end of the sound wave generator 1 is closely attached to the outer wall of the rotary kiln wall 3 through the sound guide tube 2.

[0025] The parameters of the sound wave generator 1 are as follows: frequency 40 - 70HZ, sound pressure level 90 - 129DB, compressed air flow rate 1 - 5m 3 / mm, pressure 0.1 - 0.5MPa.

[0026] In this embodiment, a composite sound insulation cover is provided outside the sound wave generating device.

[0027] The composite sound insulation cover includes an aluminum foil layer 4, a ceramic fiber layer 5 and a stainless steel layer 6; the ceramic fiber layer 5 is correspondingly arranged outside the aluminum foil layer 4; the stainless steel layer 6 is correspondingly arranged outside the ceramic fiber layer 5, which can effectively prevent noise from disturbing residents. During the day, the noise is usually required not to exceed 65 decibels, and at night not to exceed 55 decibels; the composite sound insulation cover correspondingly covers the outside of the sound wave generating device, and its inner end is closely attached to the outer wall of the rotary kiln wall.

[0028] The frequency and sound pressure level of the sound wave generator 1 on the outer wall of the rotary kiln wall 3 gradually decrease with its position height.

[0029] The usage method of the present invention is as follows:

[0030] 1. Use the thermal infrared imager 8. During the rotation of the rotary kiln, utilize the characteristic that the thicker the coating ring, the lower the temperature of the kiln skin, and through calculation and simulation, evaluate the distribution of coating rings in the kiln.

[0031] 2. According to the distribution of coating rings in the kiln, adjust the frequencies and sound pressure levels of all acoustic wave generators. The thicker the coating ring, the higher the frequency and sound pressure level generated by the acoustic wave generator. If there is a uniform coating ring at a certain cross-section of the rotary kiln, in order to improve the effect of vibrating and clearing the coating ring material, set the form of the frequency and sound pressure level generated by the acoustic wave generator as: the frequency and sound pressure level of the acoustic wave generator at the kiln top > the frequency and sound pressure level of the acoustic wave generator on the horizontal line > the frequency and sound pressure level of the acoustic wave generator directly below.

[0032] 3. Record the chemical composition, moisture content, ratio of raw materials during the pelletizing process, the preheating system of pellets, and the roasting system of pellets, and match and record them with the distribution of the sound waves of the acoustic wave generator 1, etc. Finally, form the optimal record of the sound wave distribution size and frequency, providing a reference for continuous optimization in the future.

[0033] The effects of the present invention will be further described below through specific examples and comparative examples:

[0034] The comparative example is the base period without using the device of the present invention, which is just the normal production situation. Example 2 uses the device of the present invention for production with the same raw material components as the comparative example. Example 2 is the situation of using the device of the present invention for production when the raw material conditions deteriorate further (reflected in the increase of silicon content).

[0035] Table 1 Composition ratio table of each group (dry basis weight percentage%)

[0036] Number TFe SiO2 CaO MgO Al2O3 P Comparative example 69.81 6.92 0.91 0.31 0.22 0.06 Example 1 69.81 6.92 0.91 0.31 0.22 0.06 Example 2 65.32 8.21 0.72 0.15 0.18 0.05

[0037] Table 2 Comparison table of green pellet indexes

[0038]

[0039] For convenient comparison, the same thermal process system is adopted. The thermal process system of the traveling grate is shown in Table 3

[0040] Table 3 Thermal process system of the traveling grate

[0041]

[0042] The thermal process system of the rotary kiln is as follows: kiln head: 1120 - 1190 °C, kiln tail: 800 - 1000 °C

[0043] Combined with the data analysis of the thermal infrared imager 8, it shows that the coating ring formation speed is kiln head > kiln middle > kiln tail. Therefore, the set acoustic wave parameter distribution is shown in Table 4

[0044] Table 4 Distribution of Acoustic Wave Parameters (weight percentage %)

[0045]

[0046] Table 5 Coiling Period of Each Scheme

[0047] Number Comparative example Example 1 Example 2 Coiling cycle (days) 28 35 34

[0048] Matters not elaborated in the present invention are well-known technologies.

[0049] The embodiments described above are only descriptions of the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A device for slowing down the ringing of a rotary kiln by using sound waves, characterized in that: The device comprises a sound wave generating device and a thermal infrared imager; the sound wave generating device is evenly distributed along the axial direction on the upper side, the lower side, the left side and the right side of the outer wall of the rotary kiln wall; the thermal infrared imager is arranged along the axial direction on one side of the outer wall of the rotary kiln wall.

2. The device for slowing down the ringing of rotary kiln by using sound waves according to claim 1, characterized in that: The sound wave generating device comprises a sound wave generator and a sound conduit; the output end of the sound wave generator is closely attached to the outer wall of the rotary kiln through the sound conduit.

3. The device for slowing down the ringing of rotary kiln by using sound waves according to claim 2, characterized in that: The parameters of the sound wave generator are: frequency 40-70HZ, sound pressure level 90-129DB, compressed air flow 1-5m 3 / mm, pressure 0.1-0.5MPa.

4. The device for slowing down the ringing of rotary kiln by using sound waves according to claim 1, characterized in that: A composite soundproof cover is arranged outside the sound wave generating device.

5. The device for slowing down the ringing of rotary kiln by using sound waves according to claim 4, characterized in that: The composite sound insulation cover includes an aluminum foil layer, a ceramic fiber layer and a stainless steel layer; the ceramic fiber layer is correspondingly arranged on the outside of the aluminum foil layer; the stainless steel layer is correspondingly arranged on the outside of the ceramic fiber layer; the composite sound insulation cover is correspondingly coated on the outside of the sound wave generating device, and its inner end is tightly attached to the outer wall of the kiln wall of the rotary kiln.

6. The device for slowing down the ringing of rotary kiln by using sound waves according to claim 3, characterized in that: The frequency and sound pressure level of the sound wave generator on the outer wall of the rotary kiln wall gradually decrease with the height of its position.

Images