A dry method waste residue cement rotary kiln combined oxygen-enriched combustion device and dry method waste residue cement process

Abstract

The application belongs to the technical field of cement production equipment, and discloses a dry-process waste residue cement rotary kiln combined oxygen-enriched combustion device and a dry-process waste residue cement process. The device comprises a center air duct, a cyclone air duct, a fuel air duct and an axial flow air duct which are coaxially and sequentially embedded from inside to outside. A plurality of axial flow air nozzles are arranged at the outlet end of the axial flow air duct in a circumferential interval. The device further comprises a driving assembly. The driving assembly comprises a sleeve which is arranged at the outlet end of the axial flow air duct and is rotationally connected to the outer wall of the fuel air duct. The inner wall of the sleeve is circumferentially and intervaliy provided with a through groove which is matched with the axial flow air nozzle and is in communication with the axial flow air duct. The air inlet end of the axial flow air nozzle is arranged in the through groove. A driving blade is coaxially and fixedly connected to the sleeve. The driving blade rotates under the driving of the axial flow air, drives the sleeve and the axial flow air nozzle to rotate, and forms an annular airflow barrier for the ejected axial flow air. The application solves the problem of unstable flame of the rotary kiln burner.

Description

TECHNICAL FIELD

[0001] The present scheme belongs to the technical field of cement production equipment, and particularly relates to a dry-process waste slag cement rotary kiln combined oxygen-enriched combustion device and a dry-process waste slag cement process. BACKGROUND

[0002] In the field of cement production, dry-process waste slag cement is an environmentally friendly process. It uses various types of industrial waste slag such as slag, steel slag, and fly ash as main raw materials for cement clinker production after pretreatment. This process abandons the high energy consumption and complex subsequent treatment caused by the use of large amounts of water in the wet production process, and adopts dry grinding, preheating and decomposition processes, so that the waste slag is converted into cement clinker components through physical and chemical reactions at high temperatures, improving the utilization rate of industrial waste slag and reducing the exploitation of natural raw materials and environmental pollution.

[0003] The rotary kiln, as the core equipment, is the key calcination link in the dry-process waste slag cement. Through rotation, the material is rolled and advanced in the kiln, and at the same time, the high-temperature flame provided by the burner is used to realize the continuous heating and calcination of the material. The burner in the rotary kiln precisely mixes fuel and combustion-supporting gas and sprays it into the kiln to form a high-temperature flame to provide the required heat for material calcination.

[0004] The oxygen-enriched combustion uses coal with high water content (6%-10%), and the coal powder has a water content of about 16% and a fineness of about 15%. This results in long coal combustion time, long black flame at the kiln head, low secondary air temperature, coal post-combustion, many yellow clinker blocks, and low clinker density, which are abnormal phenomena. This directly affects the clinker standard coal consumption, kiln table production capacity, clinker strength, and production cost, and other production and operation indicators.

[0005] Referring to the existing document (announcement) No. CN109059534A, a kind of adjustable high-efficiency energy-saving rotary kiln burner is disclosed, including oil gun pipe and by inside outward sequentially coaxial and sealingly set in the center wind pipe, cyclone wind pipe, fuel pipe and straight flow wind pipe of oil gun pipe oil outlet end outside, the center wind pipe, cyclone wind pipe, straight flow wind pipe all pass through pipeline and be communicated with combustion-supporting wind inlet;The straight flow wind pipe inner wall and the fuel pipe outer wall between the straight flow wind pipe inner wall and the fuel pipe outer wall form a straight flow wind channel, and a circular ring-shaped sealing block is sealingly arranged between the inner wall of one end of the straight flow wind pipe corresponding to the oil outlet end of the oil gun pipe and the outer wall of the fuel pipe, a plurality of air vents are arranged on the annular sealing block along the circumferential direction at equal intervals and penetrate the annular sealing block in the axial direction and are connected with the inner wall of the straight flow wind pipe.

[0006] For example, in the existing combustion process described above, the axial flow air (direct current air), as a direct current airflow injected along the axis of the rotary kiln, acts as an "airflow barrier" to counteract the upward or downward drift of the flame caused by uneven distribution of rotating airflow or materials within the kiln. This limits the flame's vertical displacement within the kiln body and prevents the high-temperature flame from directly impacting the kiln lining, thus avoiding localized overheating or slagging. However, because the existing burners have axial flow air outlets spaced at intervals, multiple airflows are formed. The airflow at these intervals is smaller than that at the axial flow air outlets, causing the flame at these intervals to frequently drift, especially when the coal powder quality is poor, resulting in flame instability. While a fully open continuous channel structure could eliminate circumferential airflow unevenness, it lacks support (the connecting structure between the nozzles), making it prone to deformation under the high temperature and axial flow airflow within the kiln. Summary of the Invention

[0007] The purpose of this solution is to provide a combined oxygen-enriched combustion device for a rotary kiln used in dry-process cement production from waste residue, in order to solve the problem of unstable flame in rotary kiln burners.

[0008] To achieve the above objectives, this solution provides a rotary kiln combined with oxygen-enriched combustion device for cement production from dry waste residue, comprising a central air duct, a swirl air duct, a fuel air duct, and an axial flow air duct arranged coaxially from the inside out, each air duct extending axially and being independently sealed; the outlet end of the axial flow air duct is circumferentially spaced with a plurality of axial flow nozzles, and the solution also includes a drive assembly, which includes:

[0009] A sleeve is provided at the outlet end of the axial flow duct, and the inner wall of the sleeve is rotatably connected to the outer wall of the fuel duct. The sleeve is provided with through grooves that cooperate with the axial flow nozzles at circumferential intervals. The through grooves are connected to the axial flow duct, and the air inlet end of the axial flow nozzle is provided in the through grooves.

[0010] The driving blade is coaxially and fixedly connected to the sleeve and is located in the axial flow duct.

[0011] The principle and effect of this scheme are as follows: (1) The central air duct sprays out central air, providing stable airflow support for the root of the flame; the fuel air duct sprays fuel; the swirl blades in the swirl air duct cause the airflow to rotate and then spray out, thereby mixing with the fuel sprayed out by the fuel air duct, and the axial air of the axial air duct is sprayed out through the nozzle. (2) The driving blades rotate under the push of the axial air, driving the sleeve and the axial air nozzles on the sleeve to rotate synchronously, so that the axial air sprayed by the nozzles that are originally set in a circumferential interval forms an annular airflow barrier, avoiding the flame from drifting easily at the interval position of the nozzles set in a interval, limiting the flame to a "bowl" shape, and making the flame more stable.

[0012] Furthermore, the air inlet end of the axial flow nozzle is connected to a bellows, the free end of the bellows is connected to a hollow bolt, and the through groove is provided with threads that mate with the bolt.

[0013] The principle and effect of this solution are as follows: In the dry process of cement production from waste residue, the operating conditions inside the rotary kiln change depending on the type of waste residue. Under different operating conditions, the flame is subjected to different disturbances from the rotating airflow inside the kiln, and the impact force generated by the tumbling of materials varies, requiring adjustment of the angle of the axial flow nozzle. In this solution, the air inlet end of the axial flow nozzle is connected to a corrugated pipe. Through the flexible characteristics of the corrugated pipe, the air outlet angle of the axial flow nozzle can be adjusted, allowing the axial flow to be adjusted according to the actual operating conditions inside the kiln.

[0014] Furthermore, the axial flow nozzle has a vertically arranged exhaust groove, which forms an air curtain at the outlet ends of the central air duct, the swirl air duct and the fuel air duct; the exhaust groove is equipped with a valve.

[0015] The principle and effect of this scheme are as follows: (1) Before the burner is started, each air duct and rotary kiln need to be purged to remove dust, debris and unburned fuel particles that may remain in the air duct, so as to avoid these substances being ignited by the high temperature flame when the burner is started and causing local deflagration. However, after purging the fuel air duct, central air duct and swirl air duct, the gas supply to these air ducts needs to be stopped. However, after the purging is stopped, the dust generated by the dry waste slag cement production process (such as particles after waste slag grinding and clinker dust raised in the kiln) in the field environment is easy to drift into each air duct, causing secondary pollution. (2) In this scheme, after purging, nitrogen is continued to be supplied to the axial air duct, but the gas supply is reduced and the valve is opened. The axial air nozzle rotates slowly under the drive of the sleeve. Since the exhaust groove is set vertically, an annular air curtain is formed at the outlet end of the central air duct, swirl air duct and fuel air duct to prevent impurities in the external environment from entering each air duct (mainly the fuel air duct). After the burner is started, the valve is closed, and the axial flow nozzle sprays axial flow air normally.

[0016] Furthermore, the valve includes a sealing ball and a compression spring. The outlet end of the exhaust groove has a flared structure. Both the sealing ball and the compression spring are located at the outlet end of the exhaust groove. One end of the compression spring is fixedly connected to the sealing ball, and the free end is fixedly connected to the exhaust groove. The sealing ball is used to seal the outlet end of the exhaust groove.

[0017] The principle and effect of this solution are as follows: Due to the high temperature at the burner head, electrically controlled valves are difficult to adapt to the high-temperature environment. In this solution, during the calcination process, the increased airflow strengthens the thrust of the drive blades, increases the sleeve rotation speed, and increases the centrifugal force generated by the axial flow nozzles as the sleeve rotates. This centrifugal force overcomes the preload of the compression spring, pushing the sealing ball to conform to the flared structure and seal the exhaust outlet. After purging, by reducing the airflow, the centrifugal force of the axial flow nozzles decreases, and the preload of the compression spring pushes the sealing ball away from the exhaust outlet, forming a ventilation gap. Nitrogen gas is then ejected through the exhaust channel, forming an air curtain during the sleeve's rotation.

[0018] Furthermore, the axial flow nozzle has a slot, a stop block is provided in the slot, the stop block is connected to a tension spring, and the free end of the tension spring is fixedly connected to the slot.

[0019] The principle and effect of this solution are as follows: When the exhaust trough is ventilated, if the outlet end of the axial flow nozzle is not sealed, most of the nitrogen will still be ejected from the axial flow nozzle. Therefore, it is necessary to seal the axial flow nozzle at this stage. In this solution, when the axial flow air volume is reduced, the centrifugal force of the axial flow nozzle decreases, and the preload of the tension spring pushes the baffle block into the air duct of the axial flow nozzle, blocking it, and nitrogen is ejected from the exhaust trough. During the calcination process, the air volume increases, and this centrifugal force overcomes the preload of the tension spring. The baffle block, under the action of centrifugal force, moves into the empty trough, and the air duct of the axial flow nozzle is unobstructed, allowing the axial flow nozzle to spray axial flow air normally.

[0020] Furthermore, the drive assembly also includes a gear ring, planetary gears, and a gear. The gear ring is coaxially connected to the drive blade, and the outer wall of the gear ring is fixedly connected to the inner wall of the drive blade. The gear has a through hole for the outer wall of the fuel duct to pass through, and the inner wall of the gear is coaxially fixedly connected to the outer wall of the fuel duct. The planetary gear is located between the gear ring and the gear, and meshes with the gear ring and the gear respectively. The outlet end of the fuel duct is rotatably connected to the fuel duct.

[0021] The principle and effect of this scheme are as follows: (1) In the prior art, the swirling wind flows out from the outlet to form a rotating airflow, while the fuel duct ejects fuel horizontally in the circumferential direction. Although the two form a spiral motion under the drive of the axial wind, for inferior fuels with poor combustion performance and uneven particle distribution, the mixing uniformity of fuel and swirling wind is poor, resulting in problems such as incomplete combustion and flame fluctuation. (2) In this scheme, the gear ring and the drive blade rotate synchronously. Through the meshing transmission of the planetary gear and the fixed gear, the rotation of the gear ring is converted into the revolution and rotation of the planetary gear, which indirectly drives the outlet end of the fuel duct to rotate. The direction of rotation is exactly opposite to the direction of rotation of the blades of the swirling wind, so that when the fuel is ejected from the outlet, it has an initial rotational velocity that is opposite to that of the swirling wind. At this time, the fuel rotating in the opposite direction forms a direction intersection with the swirling wind, forming a shearing force, which can make the fuel disperse and mix more evenly in the swirling wind and make the flame combustion more stable.

[0022] Furthermore, the outlet of the fuel duct is provided with a fuel nozzle, which is an annular structure. The outer wall of the fuel nozzle is hinged to the outlet end of the fuel duct, and the inner wall is hinged to the outlet end of the swirl duct. The inlet end of the axial flow duct is provided with a slider, which abuts against the inlet end of the axial flow duct. The slider is connected to a spring for resetting. The rear end of the slider is provided with a cylinder, and the piston rod of the cylinder is hinged to the slider.

[0023] The principle and effect of this solution are as follows: by controlling the piston rod stroke of the cylinder, the position of the slider is pushed. Since the fuel nozzle is hinged to the outlet end of the fuel air passage and the swirl air passage, the angle of the fuel nozzle is adjusted so that when the fuel is sprayed out, it is directed towards the swirl air and opposite to the rotation angle of the swirl air, thus forming a shearing force.

[0024] Furthermore, the swirl duct is equipped with swirl blades, and the outlet end of the swirl duct has a constricted structure; the outlet end of the central duct has a conical structure.

[0025] The principle and effect of this scheme are as follows: the swirl blades cause the combustion air flowing through to rotate, and with the constriction structure at the outlet end, the ejection speed of the rotating airflow can be accelerated while reducing the flow cross section, so as to mix more fully with the fuel ejected from the fuel duct.

[0026] Furthermore, the outer wall of the axial flow duct is provided with a smoke collection hood.

[0027] The principle and effect of this solution is that the smoke generated by combustion in the kiln is gathered and guided by the smoke hood, thus preventing the high-temperature smoke from spreading disorderly near the kiln opening.

[0028] Furthermore, the outer wall of the smoke hood is provided with castable material.

[0029] The principle and effect of this solution are as follows: the castable material has high temperature resistance and heat insulation properties, forming a protective structure on the outside of the smoke hood.

[0030] A dry process for producing cement from waste residue includes the application of a rotary kiln combined with an oxygen-enriched combustion device for producing cement from dry waste residue as described above, comprising the following steps:

[0031] Step S10: After crushing and grinding waste residues such as silica sand, copper slag, fly ash, and furnace slag, mix them with calcium carbide slag in a certain proportion to produce dry raw meal powder.

[0032] Step S20: Before starting the burner, purge each air duct of the burner, and after purging, control the wind speed of the axial air duct to open the exhaust slot and form an annular air curtain at the outlet ends of the central air duct, swirl air duct and fuel air duct.

[0033] Step S30: The raw meal powder is fed into the rotary kiln preheater for preheating and decomposition. At the same time, the combustion device is started and fuel is injected into the rotary kiln through the fuel duct. Oxygen-enriched air is introduced into the swirl duct and the axial flow duct respectively. The oxygen-enriched air and fuel are mixed in the kiln and ignited by the burner to form a high-temperature flame.

[0034] Step S40: The preheated raw materials enter the rotary kiln and are calcined at 1300℃-1450℃ to produce cement clinker;

[0035] Step S50: During the calcination process, the shape of the flame is adjusted by regulating the air volume and speed of the axial flow duct and the swirl flow duct; the angle of the fuel nozzle is adjusted by controlling the piston rod stroke of the cylinder.

[0036] Step S60: The calcined clinker is cooled to room temperature using a grate cooler;

[0037] Step S70: Grind the cooled clinker together with desulfurized gypsum and fly ash mixture to produce finished cement products. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the structure of a rotary kiln combined with oxygen-enriched combustion device for producing cement from dry waste residue according to the present invention.

[0039] Figure 2 This is a schematic diagram of the internal structure of each air duct of the combustion device of the present invention;

[0040] Figure 3 for Figure 2 A magnified view of a portion of point A in the middle;

[0041] Figure 4 This is a schematic diagram of the axial flow nozzle of the present invention in a slow rotation state;

[0042] Figure 5This is a schematic diagram of the slider, spring, and cylinder of the present invention.

[0043] The reference numerals in the accompanying drawings include: central air duct 1, swirl air duct 2, swirl blade 21, fuel air duct 3, fuel nozzle 31, slider 32, spring 33, cylinder 34, axial air duct 4, axial air nozzle 41, exhaust groove 411, empty groove 412, valve 42, sealing ball 421, compression spring 422, stop block 43, tension spring 44, drive assembly 5, sleeve 51, through groove 511, drive blade 52, bellows 53, bolt 54, gear ring 56, planetary gear 57, gear 58, smoke hood 6, castable material 7. Detailed Implementation

[0044] The following will describe the concept and technical effects of the present invention clearly and completely with reference to embodiments, so as to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention.

[0045] Example 1:

[0046] Please see Figure 1 and Figure 2 This embodiment provides a rotary kiln combined with oxygen-enriched combustion device for dry-process cement production from waste residue. It employs a central air duct 1, a swirl air duct 2, a fuel air duct 3, and an axial flow air duct 4, arranged coaxially from the inside out. Each air duct is made of heat-resistant stainless steel, extends along the burner axis, and is independently sealed by an annular sealing gasket. The outlet end of the axial flow air duct 4 is circumferentially spaced with 6-8 axial flow nozzles 41. These nozzles are made of high-temperature resistant stainless steel, and their outlet ends are flat to enhance airflow concentration.

[0047] Please see Figure 2 and Figure 3The swirl duct 2 has 4-6 fixed swirl blades 21, made of high-temperature resistant stainless steel, welded to the inner wall of the swirl duct 2 at a 45° angle. The length of the blades is adapted to the length of the swirl duct 2, which can create a strong swirl of oxygen-rich air. The outlet end of the swirl duct 2 adopts a conical constriction structure with a taper of 60°, which can accelerate the ejection speed of the swirl air while reducing the flow cross-section, enhance the swirl air's ability to entrain fuel, and improve fuel-gas mixing. The outlet end of the central duct 1 adopts a conical structure with a taper of 45° to improve flame stability. The outer wall of the axial flow duct 4 is welded and fixed with an annular smoke hood 6, which extends 50mm outside the outlet end of the axial flow nozzle 41 to gather the high-temperature flue gas generated by combustion in the rotary kiln. The outer wall of the smoke hood 6 is fixed with castable material 7 by heat-resistant steel anchors. The castable material 7 is made of high-alumina refractory castable material with a casting thickness of 80-120mm. The refractory temperature of the castable material 7 is ≥1600℃, which can prevent the smoke hood 6 from deforming and being damaged due to long-term high temperature, and can also enhance the overall structural rigidity of the smoke hood 6.

[0048] Please continue reading. Figure 2 and Figure 3 It also includes a drive assembly 5 for driving the rotation of the axial flow nozzle 41. The drive assembly 5 includes a sleeve 51 and a drive blade 52. The sleeve 51 is an annular stainless steel structure and is located on the outer side of the outlet end of the axial flow duct 4. Its inner wall is rotatably connected to the outer wall of the fuel duct 3 through a high-temperature resistant deep groove ball bearing. One end of the sleeve 51 is circumferentially evenly spaced with 6-8 through slots 511 that cooperate with the axial flow nozzle 41. The through slots 511 are annular structures and their width is adapted to the width of the air inlet end of the axial flow nozzle 41. The through slots 511 are connected to the interior of the axial flow duct 4. The air inlet end of the axial flow nozzle 41 is embedded in the through slots 511 and is sealed to the through slots 511 to prevent axial flow leakage. The drive blade 52 is coaxially arranged with the sleeve 51 and uses 4-6 spiral stainless steel blades. One end of the blade is fixedly connected to the left end of the sleeve 51 by welding, and the other end extends into the axial flow duct 4. The spiral angle of the blade is set to 30°. When the axial flow air flows along the axial flow duct 4, the airflow can act on the drive blade 52, pushing the drive blade 52 to rotate, which in turn drives the sleeve 51 and the axial flow nozzle 41 to rotate synchronously. This makes the axial flow air ejected by the originally circumferentially spaced axial flow nozzles 41 form a continuous annular airflow barrier, which compensates for the weak airflow area at the interval of the fixed axial flow nozzles 41, prevents the flame from drifting at the interval position, and limits the flame to a stable "bowl" shape.

[0049] Please continue reading. Figure 2 and Figure 3To achieve angle adjustment of the axial flow nozzle 41, the air inlet end of the axial flow nozzle 41 is welded and fixed to one end of the bellows 53. The bellows 53 is made of high-temperature resistant stainless steel with a bellows pitch of 5mm, which can achieve a bending deformation of ±30° to finely adjust the initial air outlet angle of the axial flow nozzle 41 to adapt to the airflow constraint requirements during the calcination of different waste residues (such as silica sand, copper slag, and fly ash) in the rotary kiln. The free end of the bellows 53 is connected to one end of the hollow bolt 54 by a thread. The outer wall of the bolt 54 is provided with external threads, and the through groove 511 is provided with internal threads that mate with the external threads. The bolt 54 is threadedly connected to the through groove 511. The axial flow nozzle 41 has a vertically arranged exhaust groove 411, perpendicular to the central axis of the burner at 90°. A valve 42 is installed inside the exhaust groove 411. The valve 42 includes a sealing ball 421 and a compression spring 422. Both the sealing ball 421 and the compression spring 422 are made of high-temperature resistant material. The outlet end of the exhaust groove 411 has a flared structure, i.e., a flared structure with a small inlet end and a large outlet end. The sealing ball 421 and the compression spring 422 are both located at the outlet end of the exhaust groove 411. One end of the compression spring 422 is fixedly connected to the sealing ball 421, and the free end is fixedly connected to the inner wall of the exhaust groove 411. The sealing ball 421 is used to seal the outlet end of the exhaust groove 411 and to provide airflow away from the exhaust groove 411. When the airflow is at the outlet, an air curtain is formed at the outlet ends of the central air duct 1, the swirl air duct 2, and the fuel air duct 3. The diameter of the sealing ball 421 is larger than the diameter of the air inlet end of the exhaust groove 411. The axial air nozzle 41 has a slot 412, and a baffle 43 is provided in the slot 412. The baffle 43 is close to the outlet end of the axial air nozzle 41 and is located at the front end of the exhaust groove 411. The baffle 43 is connected to a tension spring 44. The free end of the tension spring 44 is fixedly connected to the slot 412. The elastic coefficient of the tension spring 44 is greater than that of the compression spring 422, so that when the airflow is small and the rotation speed is slow, the sealing ball 421 moves away from the exhaust groove 411, and the baffle 43 blocks the air duct of the axial air nozzle 41.

[0050] Please see Figure 3 and Figure 4During the calcination process, when the air volume of the axial flow duct 4 increases, the airflow thrust on the drive blade 52 increases, and the rotation speed of the sleeve 51 increases accordingly. The centrifugal force generated by the rotation of the axial flow nozzle 41 with the sleeve 51 increases. This centrifugal force can overcome the preload of the tension spring 44. The stop block 43 is moved into the empty slot 412 by the centrifugal force. The air duct of the axial flow nozzle 41 is not blocked, and the axial flow nozzle 41 sprays axial flow air normally. Moreover, this centrifugal force will overcome the preload of the compression spring 422 and push the sealing ball 421 to fit the flared structure to seal the outlet end of the exhaust slot 411. Simultaneously, after purging all air ducts before burner startup, nitrogen can be continuously supplied to the axial flow air duct 4 while the gas supply is reduced. This causes the drive blade 52 to rotate the sleeve 51 slowly, subjecting the axial flow nozzle 41 to a small centrifugal force. The preload of the tension spring 44 pushes the stop block 43 into the air duct of the axial flow nozzle 41, blocking it. The preload of the compression spring 422 pushes the sealing ball 421 away from the outlet end of the exhaust groove 411, creating a ventilation gap. Nitrogen is then ejected through the exhaust groove 411. During the rotation of the sleeve 51, an annular air curtain (such as...) is formed at the outlet ends of the central air duct 1, the swirl air duct 2, and the fuel air duct 3. Figure 4 (As indicated by the middle arrow) to prevent impurities from the external environment from re-entering the air ducts.

[0051] Please continue reading. Figure 2 and Figure 3 The outlet end of the fuel duct 3 is coaxially rotatably connected to its adjacent swirl duct 2 and sleeve 51. The drive assembly 5 also includes a gear ring 56, planetary gears 57 and gears 58. The gear ring 56 is an internal gear ring structure, and its outer wall is fixedly connected to the inner wall of the drive blade 52 by countersunk bolts, so that the gear ring 56 and the drive blade 52 rotate synchronously. The gear 58 is an external gear, and its center has a through hole for the outer wall of the fuel duct 3 to pass through. The through hole is interference-fitted with the outer wall of the fuel duct 3, so that the gear 58 and the fuel duct 3 are coaxially fixed. There are 2-3 planetary gears with a straight tooth structure, which are evenly distributed between the gear ring 56 and the gear 58. Corresponding grooves (not shown) are opened on the sleeve 51 for the planetary gears 57 to rotate through. The planetary gears 57 mesh with the internal teeth of the gear ring 56 and the external teeth of the gear 58 at the same time.

[0052] During operation, when the drive blade 52 drives the gear ring 56 to rotate, the gear ring 56 drives the planetary gear 57 to revolve around the gear 58. Simultaneously, the planetary gear 57 rotates on its own axis, thereby driving the sleeve 51 and the outlet end of the fuel duct 3 to rotate. The rotation direction of the outlet end of the fuel duct 3 is opposite to the rotation direction of the swirling blades 21 inside the swirling duct 2 (e.g., ...). Figure 2(Two different waveform structures). When the fuel is ejected from the fuel duct 3 outlet, it has an initial rotational velocity that is opposite to that of the swirling air. The oppositely rotating fuel and the swirling air form a directional intersection, generating a strong shearing force, which makes the fuel more evenly dispersed in the swirling air, improves the mixing effect, and avoids incomplete combustion and flame fluctuation problems caused by uneven mixing.

[0053] Please see Figure 2 , Figure 3 and Figure 5 The outlet end of the fuel duct 3 is provided with a ring-shaped fuel nozzle 31. The fuel nozzle 31 is made of heat-resistant alloy material. Its outer wall is hinged to the outlet end of the fuel duct 3 through a stainless steel hinge, and its inner wall is hinged to the outlet end of the swirl duct 2 through another set of stainless steel hinges, forming a ring-shaped injection structure that can swing around the hinge point. The inner wall of the fuel nozzle 31 is evenly provided with 8-12 through injection holes with a diameter of 2-3mm. Correspondingly, a circular groove is provided at the air inlet end of the axial flow duct 4. The slider 32 is an annular stainless steel slider 32, which is embedded in the groove and slides and seals against the inner wall of the groove. A spring 33 is provided on the outer wall of the slider 32. The free end of the spring 33 is fixedly connected to the groove. The spring 33 is a compression spring, which can drive the slider 32 to return to the initial position under normal conditions. The right side of the slider 32 is hinged to the piston rod of the cylinder 34 through a fisheye bearing. The cylinder 34 is a small high-temperature resistant cylinder. By controlling the extension or retraction of the piston rod of the cylinder 34, the slider 32 can be pushed to slide left and right along the groove. The movement of the slider 32 will drive the fuel nozzle 31 to swing around the hinge point, change the fuel injection direction, make the fuel face the swirling air and form a reverse shear with the swirling air, and further enhance the mixing efficiency of fuel and combustion air.

[0054] Example 2:

[0055] To better implement the aforementioned dry waste slag cement production rotary kiln combined with oxygen-enriched combustion device, this embodiment provides a dry waste slag cement production process, including the application of the dry waste slag cement production rotary kiln combined with oxygen-enriched combustion device as described above, comprising the following steps:

[0056] Step S10: The waste residues such as silica sand, copper slag, fly ash, and slag are crushed to a particle size of ≤5mm by a jaw crusher, and then fed into a ball mill to be ground to a specific surface area of ​​≥350m² / kg. Subsequently, they are mixed with calcium carbide slag in a mixer at a mass ratio of 8:2 to produce dry raw meal powder.

[0057] In step S20, the raw meal powder is fed into the rotary kiln preheater via an elevator. In the preheater, it undergoes preheating and decomposition at 500-800℃ to remove moisture and carbonates from the raw meal. At the same time, the combustion device is started, and pulverized coal fuel (the total water content of the pulverized coal is controlled below 16%, and the fineness is controlled below 15%) is injected into the rotary kiln through the fuel duct 3. Oxygen-enriched air with an oxygen concentration of 25%-28% is introduced into the swirl duct 2 and the axial flow duct 4, respectively. After the oxygen-enriched air and pulverized coal are mixed in the kiln, they are ignited by the ignition device to form a high-temperature flame with a temperature of 1300℃-1450℃.

[0058] Step S30: Before starting the burner, purge the central air duct 1, swirl air duct 2, fuel air duct 3, and axial air duct 4 with high-pressure nitrogen for 5-8 minutes to remove residual dust, debris, and unburned fuel particles from the air ducts. After purging, close the gas supply valves of the central air duct 1, swirl air duct 2, and fuel air duct 3, leaving only the axial air duct 4 to be supplied with nitrogen. Control the nitrogen velocity at 5-8 m / s to make the drive blade 52 drive the sleeve 51 to rotate slowly, opening the exhaust groove 411 and sealing the outlet end of the axial air nozzle 41. This forms a continuous annular air curtain at the outlet ends of the central air duct 1, swirl air duct 2, and fuel air duct 3 to prevent impurities in the environment from drifting into the air ducts. After the kiln temperature rises to the ignition temperature, start the fuel supply system for ignition and combustion.

[0059] In step S40, the preheated and decomposed raw materials enter the rotary kiln and, under the action of the high-temperature flame generated by the combustion device, undergo pre-calcination, calcination, and cooling stages to complete the clinker formation process and generate cement clinker.

[0060] In step S50, during the calcination process, based on the flame shape and calcination status of the waste residue in the kiln, the axial flow air volume is increased to enhance radial constraint when the flame shows an upward trend, according to the air volume and velocity of the axial flow air duct 4 and the swirl air duct 2. At the same time, by controlling the piston rod stroke of the cylinder 34, the slider 32 is pushed to adjust the total air volume of the axial flow air duct 4, which drives the fuel nozzle 31 to adjust its angle, so that the fuel and the swirl air are mixed more fully.

[0061] In step S60, the calcined cement clinker is discharged from the kiln head of the rotary kiln and sent to the grate cooler for cooling. The clinker temperature is reduced from 1300℃-1450℃ to room temperature (≤80℃) by forced air cooling.

[0062] In step S70, the cooled clinker, desulfurized gypsum, and fly ash are fed into a cement mill at a mass ratio of 75:5:20 and ground until the specific surface area is ≥320m² / kg to produce finished cement.

[0063] The above descriptions are merely embodiments of the present invention, and common knowledge regarding specific structures and characteristics is not elaborated upon here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the structure of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A rotary kiln combined with oxygen-enriched combustion device for dry-process waste slag cement production, comprising a central air duct (1), a swirl air duct (2), a fuel air duct (3), and an axial flow air duct (4) arranged coaxially from the inside out, each air duct extending axially and being independently sealed; the outlet end of the axial flow air duct (4) is circumferentially spaced with a plurality of axial flow nozzles (41), characterized in that, It also includes a driver component (5), which includes: Sleeve (51), the sleeve (51) is located at the outlet end of the axial flow duct (4), and the inner wall of the sleeve (51) is rotatably connected to the outer wall of the fuel duct (3). The sleeve (51) is circumferentially spaced with through grooves (511) that cooperate with the axial flow nozzle (41). The through grooves (511) are connected to the axial flow duct (4), and the air inlet end of the axial flow nozzle (41) is located in the through grooves (511). Drive blade (52), which is coaxially fixedly connected to sleeve (51) and located in axial flow duct (4); The axial flow nozzle (41) has a vertically arranged exhaust groove (411) so that the axial flow forms an air curtain at the outlet end of the central air duct (1), the swirl air duct (2) and the fuel air duct (3); the exhaust groove (411) is provided with a valve (42).

2. The dry-process waste residue cement rotary kiln combined with oxygen-enriched combustion device according to claim 1, characterized in that: The air inlet end of the axial flow nozzle (41) is connected to a bellows (53), the free end of the bellows (53) is connected to a hollow bolt (54), and the through groove (511) is provided with a thread that matches the bolt (54).

3. The dry-process waste residue cement rotary kiln combined with oxygen-enriched combustion device according to claim 1, characterized in that: The valve (42) includes a sealing ball (421) and a compression spring (422). The outlet end of the exhaust groove (411) has a flared structure. The sealing ball (421) and the compression spring (422) are both located at the outlet end of the exhaust groove (411). One end of the compression spring (422) is fixedly connected to the sealing ball (421), and the free end is fixedly connected to the exhaust groove (411). The sealing ball (421) is used to seal the outlet end of the exhaust groove (411).

4. The dry-process waste residue cement rotary kiln combined with oxygen-enriched combustion device according to claim 3, characterized in that: The axial flow nozzle (41) has a slot (412), and a stop block (43) is provided in the slot (412). The stop block (43) is connected to a tension spring (44), and the free end of the tension spring (44) is fixedly connected to the slot (412).

5. The dry-process waste residue cement rotary kiln combined with oxygen-enriched combustion device according to claim 1, characterized in that: The drive assembly (5) further includes a gear ring (56), a planetary gear (57), and a gear (58). The gear ring (56) is coaxially connected to the drive blade (52), and the outer wall of the gear ring (56) is fixedly connected to the inner wall of the drive blade (52). The gear (58) has a through hole through which the outer wall of the fuel duct (3) passes, and the inner wall of the gear (58) is coaxially fixedly connected to the outer wall of the fuel duct (3). The planetary gear (57) is located between the gear ring (56) and the gear (58), and meshes with the gear ring (56) and the gear (58) respectively. The outlet end of the fuel duct (3) is rotatably connected to the fuel duct (3).

6. The dry-process waste residue cement rotary kiln combined with oxygen-enriched combustion device according to claim 1, characterized in that: The outlet of the fuel duct (3) is provided with a fuel nozzle (31), which is an annular structure. The outer wall of the fuel nozzle (31) is hinged to the outlet end of the fuel duct (3), and the inner wall is hinged to the outlet end of the swirl duct (2). The inlet end of the axial duct (4) is provided with a slider (32), which abuts against the inlet end of the axial duct (4). The slider (32) is connected to a spring (33) for resetting. The rear end of the slider (32) is provided with a cylinder (34), and the piston rod of the cylinder (34) is hinged to the slider (32).

7. The dry-process waste residue cement rotary kiln combined with oxygen-enriched combustion device according to claim 1, characterized in that: The swirl duct (2) is equipped with swirl blades (21), and the outlet end of the swirl duct (2) is a constricted structure; the outlet end of the central duct (1) is a conical structure.

8. The dry-process waste residue cement rotary kiln combined with oxygen-enriched combustion device according to claim 1, characterized in that: The outer wall of the axial flow duct (4) is provided with a smoke hood (6); the outer wall of the smoke hood is provided with a casting material (7).

9. A dry process for producing cement from waste residue, comprising the application of a rotary kiln combined with an oxygen-enriched combustion device as described in any one of claims 1-8, characterized in that, Includes the following steps: Step S10: After crushing and grinding, silica sand, copper slag, fly ash, and slag waste are mixed with calcium carbide slag in a certain proportion to produce dry raw meal powder. Step S20: Before the burner is started, the air ducts of the burner are purged, and after purging, the wind speed of the axial flow air duct (4) is controlled to open the exhaust slot (411) and form an annular air curtain at the outlet end of the central air duct (1), the swirl air duct (2) and the fuel air duct (3); Step S30: The raw material powder is fed into the rotary kiln preheater for preheating and decomposition. At the same time, the combustion device is started and fuel is injected into the rotary kiln through the fuel air duct (3). Oxygen-enriched air is introduced into the swirl air duct (2) and the axial air duct (4) respectively. The oxygen-enriched air and fuel are mixed in the kiln and ignited by the burner to form a high-temperature flame. Step S40: The preheated raw materials enter the rotary kiln and are calcined at 1300℃-1450℃ to produce cement clinker; Step S50: During the calcination process, the shape of the flame is adjusted by adjusting the air volume and speed of the axial flow duct (4) and the swirl flow duct (2); the angle of the fuel nozzle (31) is adjusted by controlling the piston rod stroke of the cylinder (34); Step S60: The calcined clinker is cooled to room temperature using a grate cooler; Step S70: Grind the cooled clinker together with desulfurized gypsum and fly ash mixture to produce finished cement products.

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