Top spray feeding type high-temperature activation furnace and control method thereof

Abstract

The invention provides a top-spraying feeding type high-temperature activation furnace and a control method thereof.The activation furnace comprises a vertical furnace body, and a fuel nozzle, a first combustion-supporting air nozzle, a cooling liquid nozzle and a cold air nozzle are sequentially arranged on a first section, a second section, a third section and a fourth section in a hearth of the vertical furnace body from top to bottom; a reduction gasification area, a peroxidation combustion area, a primary cooling area and a secondary cooling area are sequentially defined in the hearth so as to control the temperature in different areas; the fuel nozzles are arranged in pairs and arranged around the center circle of the hearth in a symmetrical tangent circle opposite spraying mode so that opposite flow can generate turbulent disturbance in the center area of the hearth to establish a first swirling flow field, and a feeding nozzle is arranged on the furnace top of the vertical furnace body to be communicated with the hearth and spray materials towards the first swirling flow field to form top combustion. Therefore, the high-temperature activation treatment of the livestock and poultry excrement is realized.

Description

Technical Field

[0001] This invention relates to the field of high-temperature activation furnace technology, and in particular to a top-spray feeding high-temperature activation furnace and its control method for high-temperature activation treatment of livestock and poultry manure. Background Technology

[0002] High-temperature activation technology is a technique that alters the physical structure, chemical properties, or composition of a target substance by treating it in a high-temperature environment. Its core principle is to utilize the energy provided by high temperatures to break the substance's original chemical bonds, promote molecular recombination, or remove impurities and create porous structures, thereby achieving the purpose of "activation." Today, high-temperature activation technology is widely used in various industries due to its ability to efficiently change the properties of materials.

[0003] Animal manure, as a major type of organic solid waste, contains essential nutrients such as phosphorus and potassium, which are necessary for plant growth and are high-quality fertilizer raw materials. However, improper treatment can easily pollute the environment and waste resources. To address this, existing technologies have proposed a wet acid leaching process to extract high-value elements from it.

[0004] For example, taking chicken manure as an example, the main ash phases in raw chicken manure are CaO and (Ca,Mg)CO3, indicating that phosphorus and potassium mainly exist in organic form. Therefore, only after chicken manure is activated at high temperature can the organic phosphorus in it be converted into inorganic phosphorus, thus having the activity of wet extraction, so as to combine with calcium to form calcium pyrophosphate (Ca2P2O7). Calcium pyrophosphate is more soluble in acidic solutions. Therefore, high-temperature activation treatment and ensuring its conversion rate are prerequisites for adapting to wet acid leaching processes and recovering high-value elements from such livestock and poultry manure.

[0005] However, in the existing technology, there is no high-temperature activation furnace specifically designed for the high-temperature activation treatment of livestock and poultry manure, so it is urgent for those skilled in the art to design and implement it. Summary of the Invention

[0006] The main objective of this invention is to provide a top-spray feeding high-temperature activation furnace and its control method to achieve high-temperature activation treatment of livestock and poultry manure.

[0007] To achieve the above objectives, according to one aspect of the present invention, a top-feed high-temperature activation furnace is provided, comprising: a vertical furnace body, wherein fuel nozzles, a first combustion air nozzle, a coolant nozzle, and a cold air nozzle are sequentially arranged in the furnace chamber from top to bottom in the first, second, third, and fourth sections to define a reduction gasification zone, an oxygen-overflow combustion zone, a primary cooling zone, and a secondary cooling zone for zoned temperature control; the fuel nozzles are arranged in pairs in a symmetrical tangential spray pattern around the center circle of the furnace chamber to generate turbulent disturbances in the central region of the furnace chamber and establish a first swirling flow field; a feed nozzle is provided at the top of the vertical furnace body to connect to the furnace chamber and spray material toward the first swirling flow field to form top combustion.

[0008] In a possible preferred embodiment, the feed nozzle includes: a manifold, a feed pipe, a combustion air pipe, and swirl vanes. The swirl vanes are disposed at the nozzle section inside the manifold. The upstream section of the manifold is connected to the combustion air pipe to form a central flow channel filled with combustion air inside the manifold. The feed pipes are connected in pairs to the downstream section of the manifold and are arranged in a symmetrical tangential spray pattern around the inner diameter of the manifold. The feed is sprayed to the outer annular gap of the central flow channel to counteract the flow, forming a differential speed jacket state with the central flow channel. The feed is guided by the swirl vanes and sprayed into the first swirl field inside the furnace, and diffuses at the adjacent furnace wall to form a return flow zone that intersects with the first swirl field.

[0009] In a possible preferred embodiment, the nozzle section located downstream of the swirl blades in the manifold is provided with a constriction neck, which connects the swirl blades to the nozzle of the manifold in a constriction-expansion undulating manner within the pipe.

[0010] In a possible preferred embodiment, the manifold is provided with a water-cooled jacket layer, and the water-cooled jacket layer is connected to a pair of cooling water circulation nozzles.

[0011] In a possible preferred embodiment, the temperature of each zone in the furnace of the vertical furnace body is controlled according to the reaction temperature field as follows: reduction gasification zone 1250~1150℃, oxygen combustion zone 1100~1000℃, primary cooling zone 950~850℃, and secondary cooling zone 700~600℃.

[0012] In a possible preferred embodiment, the coolant nozzles are arranged in a ring at intervals on the third section of the furnace, spraying water mist into the furnace to form a ring spray around the swirling field. The rapid cooling of the flue gas causes the salt ash to precipitate in the form of microcrystalline particles, forming a density difference with the flue gas.

[0013] In a possible preferred embodiment, the third section inside the furnace of the vertical furnace body is further provided with a denitrification agent nozzle, which is located below the coolant nozzle.

[0014] In a possible preferred embodiment, the top-feed high-temperature activation furnace further includes: an ash collection device and a multi-pass membrane wall boiler, wherein the multi-pass membrane wall boiler is connected to the vertical furnace body to receive waste heat recovery from flue gas, and the ash collection device is located at the bottom of the vertical furnace body and the multi-pass membrane wall boiler to receive and recover settled ash.

[0015] To achieve the above objectives, according to another aspect of the present invention, a control method for a top-spray feeding high-temperature activation furnace as described in any of the above embodiments is also provided, comprising the following steps:

[0016] Fuel is mixed with combustion air and ignited by symmetrical tangential injection through fuel nozzles toward the center circle of the furnace, forming the first swirling field in the furnace; solid particles of livestock and poultry manure are mixed with combustion air and injected toward the top of the first swirling field through feed nozzles, and the reduction gasification zone is controlled to be maintained at 1250~1150℃.

[0017] The first combustion air nozzle supplies combustion air into the furnace to maintain the temperature of the oxygen-excessive combustion zone at 1100~1000℃.

[0018] The coolant nozzle sprays water mist to control the water content of the flue gas to below 20%. Rapid cooling of the flue gas promotes the precipitation of salt ash in the form of microcrystalline particles, and keeps the primary cooling zone at 950~850℃.

[0019] Control the cold air nozzles to deliver air at a speed of 15-20 m / s, and keep the secondary cooling zone at 700~600℃.

[0020] To achieve the above objectives, according to another aspect of the present invention, a control method for a top-spray feeding high-temperature activation furnace as described in any of the above embodiments is also provided, comprising the following steps:

[0021] The fuel is mixed with combustion air and ignited by symmetrical tangential injection into the center circle of the furnace through fuel nozzles, forming the first swirling flow field in the furnace and controlling the reduction gasification zone to maintain 1250~1150℃.

[0022] The incoming airflow, which is mixed with solid particles of livestock and poultry manure, is sprayed symmetrically in a tangential circle into the inner diameter of the manifold through the spray pipe. The flow rate of the combustion air and the incoming airflow are controlled to form a speed difference, so that the incoming airflow flows into the outer annular gap of the central flow channel and forms a speed difference jacket state with the central flow channel. After the vortex and pulsating turbulence are formed at the interface of the two fluid layers, the mixture of gas and solid is sprayed into the first swirl field through the swirl blades and diffuses at the adjacent furnace wall to form a return flow zone that intersects with the first swirl field.

[0023] The first combustion air nozzle supplies combustion air into the furnace to maintain the temperature of the oxygen-excessive combustion zone at 1100~1000℃.

[0024] The coolant nozzle sprays water mist to control the water content of the flue gas to below 20%. Rapid cooling of the flue gas promotes the precipitation of salt ash in the form of microcrystalline particles, and keeps the primary cooling zone at 950~850℃.

[0025] Control the cold air nozzles to deliver air at a speed of 15-20 m / s, and keep the secondary cooling zone at 700~600℃.

[0026] The top-feed high-temperature activation furnace and its control method provided by this invention ingeniously design a vertical furnace structure to meet the gradient temperature field required for the activation of ash from solid particles of livestock and poultry manure. Simultaneously, a specially designed fuel nozzle anti-spray structure can establish a top-burning swirling flow field within the furnace to generate sufficient centrifugal force. Combined with the top-spraying of the feed nozzle, this creates opposing airflows that generate strong turbulent disturbances in the central region of the furnace, improving the mixing efficiency of solid particles and high-temperature flue gas. This ensures that micron-sized manure particles are uniformly distributed radially, while maintaining a stable axial velocity that balances with particle settling velocity. This resolves the contradiction between small particles escaping with the airflow and large particles settling too quickly, allowing solid particles to be dispersed in a strong swirling flow field. This avoids the formation of localized dense phase zones by large particles within the furnace, ensuring that the activation temperature field in the reduction and gasification zone acts uniformly on particles of every size.

[0027] In addition, the design of the first combustion air nozzle can further lift the solid particles, prevent them from settling rapidly in the furnace, and mix them with the incompletely burned solid particles to form an oxygen-rich combustion zone to quickly complete the combustion and further ensure the activation conversion rate.

[0028] Meanwhile, by setting up coolant nozzles and cold air nozzles / cold air spray holes, a dual-medium synergistic cooling system of "water spray + cold air" (primary cooling zone and secondary cooling zone) is formed. The latent heat exchange of water mist is cleverly utilized to promote the rapid nucleation of salt molecules. This mechanism enables the salt ash to form loose particles with uniform particle size distribution, avoiding the wet and sticky agglomeration caused by water spray alone. The subsequent rapid cooling through the air curtain formed by the cold air nozzle can avoid the cooling lag problem caused by the large heat capacity of coarse particles. It matches the rapid heat exchange characteristics of micron-sized particles and prevents the ash from agglomerating due to uneven cooling.

[0029] This achieves the goal of high-temperature activation of solid particles of livestock and poultry manure, providing the necessary conditions for the recovery of high-value elements such as phosphorus and potassium from ash. Attached Figure Description

[0030] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0031] Figure 1This is a schematic cross-sectional view of the vertical furnace body of the top-spray feeding high-temperature activation furnace of the present invention.

[0032] Figure 2 This is an enlarged schematic diagram of the top cross-sectional structure of the vertical furnace body of the top-spray feeding high-temperature activation furnace of the present invention;

[0033] Figure 3 for Figure 2 Enlarged cross-sectional view of the spray pipe and manifold at point AA;

[0034] Figure 4 This is a schematic diagram of the cross-sectional distribution structure of the fuel nozzles in the vertical furnace chamber of the top-feed high-temperature activation furnace of the present invention.

[0035] Figure 5 This is a schematic diagram of the overall structure of the top-spray feeding high-temperature activation furnace of the present invention;

[0036] Figure 6 This is a schematic diagram of the steps in the first embodiment of the top-spray feeding high-temperature activation furnace control method of the present invention;

[0037] Figure 7 This is a schematic diagram of the steps in the second embodiment of the top-spray feeding high-temperature activation furnace control method of the present invention.

[0038] Explanation of reference numerals in the attached figures

[0039] Vertical furnace body 1, feed nozzle 2, reflux zone 3, ash collection device 5, multi-pass membrane wall boiler 6, silo 7, fuel nozzle 11, center circle 10, first combustion air nozzle 12, coolant nozzle 13, cold air nozzle 14, denitrifying agent nozzle 15, manifold 21, spray pipe 22, combustion air pipe 23, swirl vane 24, inner diameter circle 25, necking 26, water-cooled jacket layer 27, cooling water circulation nozzle 28, scraper conveyor 51, elevator 52, baffle plate 61. Detailed Implementation

[0040] To enable those skilled in the art to better understand the technical solutions of the present invention, the specific technical solutions of the present invention will be clearly and completely described below in conjunction with embodiments, so as to help those skilled in the art further understand the present invention. Obviously, the embodiments described in this application are merely some embodiments of the present invention, and not all embodiments. It should be noted that, for those skilled in the art, the embodiments and features in the embodiments of this application can be combined with each other without departing from the concept of the present invention and without conflict. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the disclosure and protection scope of the present invention.

[0041] Furthermore, the terms "first," "second," "S100," "S200," etc., used in the specification, claims, and drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such features can be interchanged where appropriate so that embodiments of the invention described herein can be implemented in orders other than those described herein. At the same time, the stages described in each step are not necessarily to be implemented in the same step; it should be understood that the implementation order of the contents of each step stage can be adjusted and interchanged without violating the inventive concept, so that embodiments of the invention described herein can be implemented in orders other than those described herein. Additionally, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. Unless otherwise expressly specified and limited, the terms "set," "arrange," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium; or a connection within two elements. Those skilled in the art can understand the specific meaning of the above terms in this case based on the specific circumstances and in conjunction with existing technology.

[0042] To achieve high-temperature activation treatment of livestock and poultry manure, the usual approach is to crush the raw material before feeding it into a high-temperature kiln for activation. However, many difficulties arise in actual implementation. For example, dry chicken manure contains fibrous materials, and current crushing equipment cannot meet the requirement of crushing it to the micron level. It can generally be crushed into fine particles of 200-600μm (D50≈300μm, D90≈530μm). Forcing it to be crushed to the micron level would drastically increase costs and make it uneconomical. Furthermore, this particle size range is more suitable for wet extraction of phosphorus and potassium from the activated ash residue.

[0043] Therefore, considering the feeding characteristics of excessively large original crushed chicken manure particles, a longer reaction residence time is required, and high-temperature activation uniformity must be ensured. However, conventional rotary kilns and circulating fluidized bed furnaces cannot support the activation residence time and activation uniformity of such large-diameter particles during the reduction gasification process, making it impossible to achieve the expected activation conversion rate.

[0044] Therefore, such as Figures 1 to 4 As shown, this invention provides a top-feed high-temperature activation furnace, an example of which includes: a vertical furnace body 1, wherein the vertical furnace body 1 adopts an integrated structure of top-fired insulated furnace chamber, and the furnace chamber can be constructed of steel plate and heat-insulating refractory materials (such as composite aluminosilicate fiber + lightweight heat-insulating refractory material + heavy refractory material), which can reduce the heat loss rate to below 5%. This meets the activation temperature requirements for low-calorific-value (as low as 1500 Kcal / kg) solid waste.

[0045] Among them, such as Figure 1 As shown, the top of the vertical furnace body 1 is provided with a feed nozzle 2 to connect to the furnace chamber. The furnace chamber of the vertical furnace body 1 is provided with a fuel nozzle 11 in the first section from top to bottom, a first combustion air nozzle 12 in the second section, a coolant nozzle 13 in the third section, and a cold air nozzle 14 in the fourth section, so as to define a reduction gasification zone, an oxygen combustion zone, a primary cooling zone, and a secondary cooling zone in the furnace chamber for zoned temperature control.

[0046] Among them, such as Figure 1 , Figure 4 As shown, to increase the suspension time of fecal solid particles in the furnace, the fuel nozzles 11 can be configured as four opposing integrated nozzles, evenly arranged at 90° intervals along the top sidewall of the furnace body, and symmetrically ignited at a tangential angle of 5-15° towards a central circle 10 with a diameter of 1 / 5-1 / 4 of the furnace inner diameter at a speed of 70-100 m / s. This forms a countercurrent airflow, generating turbulent disturbance in the central region of the furnace, creating a first swirling flow field (swirling intensity can reach 4 or higher) within the furnace to generate sufficient centrifugal force. Preferably, the feed nozzles 11 can spray material along the outer diameter of the central circle 10 towards the top of the first swirling flow field, so that the material is drawn into the swirling flow, improving the mixing efficiency of solid particles and high-temperature flue gas. At the same time, the strong turbulent disturbance within the swirling flow can also effectively extend the average residence time of solid particles in the reduction gasification zone, thereby solving the problem of insufficient local reaction during the high-temperature activation process of solid particles.

[0047] On the other hand, considering that biomass pellets (such as chicken manure) are prone to agglomeration and difficult to mix, if the sprayed material is not mixed evenly, it will not only affect the uniformity of heating when each pellet is sprayed into the furnace, but also cause the agglomerated pellets to fall more quickly, thus affecting the activation efficiency.

[0048] Therefore, to further ensure activation efficiency, in an optional embodiment, this example also provides a feed nozzle 2 to promote the uniformity of gas-solid mixing between fecal solid particles and combustion air, and to achieve diffused and uniform spraying of the material within the furnace. Figures 2 to 3As shown, the feed nozzle 2 example includes: a manifold 21, a spray pipe 22, a combustion air pipe 23, and a swirl vane 24. The swirl vane 24 is disposed at the nozzle section within the manifold 21. The upstream section of the manifold 21 connects to the combustion air pipe 23 to form a central flow channel filled with combustion air within the manifold 21. The spray pipes 22 are connected in pairs to the downstream section of the manifold 21, arranged symmetrically around the inner diameter circle 25 of the manifold 21 in a tangential spray pattern. This allows the incoming airflow, mixed with combustion air and solid particles of livestock manure, to be swirled, sprayed, and converged into the outer annular gap of the central flow channel. Under the action of the swirl, pre-mixing occurs. During this process, the airflow velocity in the central flow channel can be controlled to be greater than the incoming airflow velocity, so that the incoming airflow and the central flow channel form a differential speed jacket state, thereby forming vortices and pulsating turbulent mixing of gas and solid at the interface of the two fluid layers.

[0049] With this configuration, different media (solid / gas) can be guided by the jacketed coaxial multi-layer channel, generating shearing, turbulence, and diffusion within the manifold 21. This means that the outer solid flow is "encased, sheared, and penetrated by the inner airflow." Thus, a significant velocity gradient exists between the high-speed inner core airflow and the outer jacketed flow of the fecal particle-combustion air mixture. The high-speed and low-speed fluids generate strong shearing forces, which disrupt the boundary layer stability of the outer core fluid. The shearing action creates intense vortices and pulsating turbulence at the interface between the two fluid layers. Turbulence is the key driving force for the mixing of different fluid micro-clusters. Furthermore, the bidirectional exchange of mass, momentum, and energy between the two fluids allows the combustion air to penetrate deeply into the fecal particle cluster, while simultaneously dispersing the fecal particles uniformly into the combustion air. This achieves efficient, rapid, and uniform mixing of the gas-solid two-phase flow within a limited space.

[0050] Subsequently, the uniformly mixed gas-solid feed material is guided by the swirl blades 24 and sprayed into the first swirl field of the furnace in the form of a rotating jet. During this process, the rotating jet will generate strong centrifugal force and radial pressure gradient, which greatly enhances the entrainment, shearing and mixing capacity of the external core flow, forming a larger-scale turbulent vortex structure, thereby achieving diffused and uniformly spread gas-solid mixed feed material in the furnace.

[0051] Furthermore, in order to ensure more thorough gas-solid mixing of the aerosol guided by the swirl blades 24 before external spraying, in optional embodiments, such as... Figure 2As shown, a constriction 26 can be provided at the nozzle section downstream of the swirl vane 24 within the manifold 21. The constriction 26 connects the swirl vane 24 to the nozzle of the manifold 21 in an undulating, contracting-expanding manner within the pipe. This forms a mixing section, providing additional space and time for the mixed flow, allowing for more thorough turbulent exchange and diffusion processes. Furthermore, the outlet of the mixing section can be configured with different geometries, such as a constriction or an irregularly shaped outlet, to further control the accelerated fluid or alter the flow field structure, promoting more thorough mixing, turbulent exchange, and diffusion processes.

[0052] One of the most noteworthy things is that, Figure 1 As shown, while the feed nozzle 2 sprays material into the first swirling field inside the furnace, it also diffuses at the adjacent furnace wall to form a reflux zone 3 that intersects with the first swirling field, thus suspending and guiding the solid particles of livestock and poultry manure. At this time, under the lifting effect of the refluxed flue gas, the reaction residence time of the solid manure particles will be greatly increased, thereby further solving the problem of insufficient local reaction during the high-temperature activation process of solid particles.

[0053] Furthermore, in order to protect the head of the feed nozzle 2 from the high-temperature heat radiation inside the furnace and extend the nozzle's service life, in optional embodiments, such as Figure 2 As shown, the manifold 21 is provided with a water-cooled jacket layer 27, and the water-cooled jacket layer 27 is connected to a pair of cooling water circulation nozzles 28 for water-cooled circulation and cooling.

[0054] For example, such as Figure 2 As shown, during the implementation process, diesel fuel is mixed with combustion air and ignited by symmetrical tangential injection into the center circle 10 of the furnace through fuel nozzle 11, forming the first swirling field. Solid particles of livestock and poultry manure with a particle size of 200~600μm are mixed with combustion air at a solid-gas ratio of 2:1 and injected into the top of the first swirling field in the furnace through feed nozzle 2. This causes the powder and diesel fuel to form an interlaced three-dimensional swirling flow, and the high-temperature flue gas generated by combustion also forms a swirling thermal field distribution and is burned at the top, so that the combustion heat is evenly contacted with the solid particles in the reduction gasification zone, maintaining the temperature of the reduction gasification zone at 1250~1150℃ and accelerating the activation reaction.

[0055] This allows for a dynamic balance between the gravity of solid particles and the lifting force of the airflow, creating a stable suspended flow within the furnace. This ensures a uniform radial distribution of solid particles of this size, while maintaining a stable axial velocity of 0.8-1.5 m / s, balancing with the particle settling velocity. This resolves the mismatch between small particles escaping with the airflow and large particles settling too quickly, a problem common in traditional furnaces. Furthermore, the solid particles maintain a dispersed distribution within the strong swirling flow field, significantly improving the efficiency of filling the furnace space compared to traditional furnaces. This prevents coarse particles from forming localized dense phase zones within the furnace, ensuring that the temperature field in the 1250-1150℃ reduction gasification zone acts uniformly on particles of every size.

[0056] This design allows for better control of the residence time of solid particles with a diameter of 200-600μm within the furnace. Compared to bottom-fired furnaces, this method avoids the problem of long residence times for small particles and short residence times for large particles found in bottom-fired furnaces (where approximately 60% of large particles settle rapidly to the bottom due to gravity and cannot rise with the flue gas). The more uniform temperature distribution within the furnace also ensures that the residence time deviation in the reduction and gasification zone is controlled within ±5%, significantly improving the activation conversion rate of organic phosphorus to inorganic phosphorus in chicken manure.

[0057] Furthermore, to promote complete combustion of solid particles, in a preferred embodiment, the first combustion air nozzle 12 installed on the second section of the furnace can, on the one hand, deliver combustion air to the swirling flow field to mix intensely with the incompletely burned solid particles, forming an oxygen-rich combustion zone (temperature controlled at 1100~1000℃), and quickly achieving complete combustion. On the other hand, the high-speed airflow field input at 70-100m / s can maintain a high-velocity swirling flow field and form a film lifting effect, which precisely counteracts the gravitational settling tendency of particles within these particle size ranges, thus lifting the solid particles and preventing them from settling rapidly in the furnace. At the same time, the gradient distribution of the reducing and oxidizing atmospheres matches the pyrolysis process of the particles from the center to the edge, thereby satisfying the gradient temperature field (temperature difference controlled within ±30℃) required for ash activation of solid particles of these particle sizes, realizing a stepwise reaction from the release of volatiles to the combustion of fixed carbon.

[0058] Furthermore, considering the melting point characteristics of mixed ash such as CaO (melting point 2572℃), KCl (melting point 770℃), and Ca2P2O7 (melting point 970℃) in chicken manure ash (the softening temperature of the main salts is about 800-950℃), in this example, coolant nozzles 13 and cold air nozzles 14 are respectively installed in the third and fourth sections of the furnace to form a "water spray + cold air" dual-medium synergistic cooling and rapid cooling section in the lower part of the furnace (between the activation section and the dust removal section). This rapidly cools the salt ash, causing the salts to precipitate in the form of microcrystalline particles, thus avoiding the agglomeration of salts caused by the delayed rapid cooling in traditional furnace types.

[0059] Specifically, in the preferred embodiment, the coolant nozzles 13 are arranged in a ring at intervals on the third section of the furnace (preferably with a spacing of 1 / 6 of the furnace diameter), spraying water mist (e.g., atomized particle size less than 100μm) into the furnace to form a ring spray around the swirling flow field. This creates uniform contact with the salt ash in the radial cross-section, increasing the collision efficiency between the droplets and ash particles by more than 60% compared to traditional single-nozzle rapid cooling. This ensures synchronous cooling of the salt ash at different radial positions, solving the problem of localized salt melting residue caused by radial temperature differences in the furnace. This achieves preliminary rapid cooling of the flue gas and ash in the furnace, controlling the rapid cooling temperature in the primary cooling zone at 950~850℃ and the flue gas moisture content below 20%. Simultaneously, the circumferentially arranged cold air nozzles 14 form an air curtain for secondary cooling at a wind speed of 15-20m / s, controlling the rapid cooling temperature in the secondary cooling zone at 700~600℃.

[0060] This setup allows for initial rapid cooling via water spray. The latent heat exchange of the water mist promotes rapid nucleation of salt molecules, resulting in loosely distributed salt ash particles with a uniform size distribution (10-50 μm), avoiding the wet, sticky agglomeration caused by a single water spray. Subsequent cooling with a curtain of cold air (15-20 m / s) lowers the temperature of the flue gas and ash from over 1150°C in the activation section of the reduction gasification zone to 600°C within 1-2 seconds. This avoids the cooling lag caused by the large heat capacity of coarse particles and matches the rapid heat exchange characteristics of particles of this size, preventing ash agglomeration due to uneven cooling.

[0061] This approach avoids ash agglomeration caused by water spraying alone and solves the problem of high cold air consumption in air-cooled cooling alone. It provides stable flue gas humidity conditions for subsequent ash collection processes. At the same time, rapid cooling of flue gas can also promote the precipitation of salt ash in the form of microcrystalline particles, forming a density difference with the flue gas, accelerating sedimentation, reducing the amount of salt particles entering the downstream washing system, and reducing the risk of salt scale blockage in subsequent equipment.

[0062] Furthermore, in order to reduce NOx emissions, in optional implementations, such as Figure 1 As shown, the vertical furnace body 1 is further provided with a denitrification agent nozzle 15 on the third section of the furnace chamber. It is located below the coolant nozzle 13 and can be used to spray a denitrification agent containing a dilute solution of urea or ammonia into the furnace chamber through a dual-fluid spray gun atomized by compressed air. The agent is fully covered and mixed with the high-temperature flue gas. Together with the water mist sprayed by the coolant nozzle 13, the rapid cooling temperature of the primary cooling zone is controlled at 950~850℃, reaching the temperature window for high-temperature denitrification in the furnace, thus inhibiting and reducing NOx generation.

[0063] According to the example above, the vertical furnace body 1 after implementation has an oxygen content of 3-6 wt% in its outlet flue gas, and a particle residence time of 2-9 seconds. Among them, large particles that fall with vertical acceleration from the center are called escaped particles, accounting for about 1 / 4, and these small number of particles have a residence time of 2-4 seconds. Most particles form a swirling flow and disperse in the furnace or adhere to the wall and enter the recirculation zone 3, forming a suspension effect. Most of these particles have a residence time of 5-9 seconds. In addition, the calorific value of chicken manure with a moisture content of 10-30 wt% is between 1500-3000 kcal / kg. At this calorific value, only a small amount of supplementary combustion or no supplementary combustion is needed to sustain combustion to above 1150℃. Under the premise of the above 3T (temperature, turbulence, residence time) flow field, the conversion rate of combustibles is guaranteed to be above 99%.

[0064] Furthermore, such as Figure 5 As shown, in an optional embodiment, the top-feed high-temperature activation furnace also includes, for example, an ash collection device 5 and a multi-pass membrane wall boiler 6. The cooling section of the secondary cooling zone at the bottom of the vertical furnace body 1 is connected to the multi-pass membrane wall boiler 6, receiving cooled flue gas at approximately 700-600°C for waste heat recovery. In a preferred embodiment, the multi-pass membrane wall boiler 6 is equipped with baffles 61 to allow the flue gas to flow back and forth multiple times, further settling the dust. The flue gas then continues to enter downstream equipment, such as a dust collector, for potassium recovery. The ash collection device 5 includes, for example, a scraper conveyor 51 and an elevator 52. The scraper conveyor 51 is located at the bottom of the vertical furnace body 1 and the multi-pass membrane wall boiler 6 to receive the recovered and settled ash, which is then centrally transported to the silo 7 via the elevator 52.

[0065] The actual activated furnace bottom ash accounts for about 30% (mainly large particles larger than 500μm), and the ash from the first two passes of the multi-pass membrane wall boiler 6 accounts for about 40-50% (mainly small and medium-sized particles of 200-400μm). That is, the pre-treatment (vertical furnace 1 + multi-pass membrane wall boiler 6) recovers more than 90% of the phosphates. The remaining 20% ​​of fly ash enters the dust collector with the flue gas. The particulate matter concentration in the flue gas after ash collection by the dust collector is ≤20mg / Nm3, that is, the dust collector recovers potassium from the fly ash. This design can efficiently recover the migrated phosphorus and potassium in stages, achieving nearly 100% recovery and utilization of effective phosphorus and potassium components.

[0066] In addition, the flue gas after ash collection can continue to enter the SCR reactor and flue gas scrubbing tower to completely remove acidic pollutants such as NOx and SO2 before being discharged to the chimney.

[0067] On the other hand, such as Figure 6 As shown, corresponding to the above example, the present invention also provides a control method for a top-spray feeding high-temperature activation furnace, the example steps of which include:

[0068] Step S1: Fuel is mixed with combustion air and ignited by symmetrical tangential injection into the center circle 10 of the furnace through fuel nozzle 11, forming a first swirling field in the furnace; solid particles of livestock and poultry manure are mixed with combustion air and injected into the top of the first swirling field through feed nozzle 2, and the reduction gasification zone is controlled to be maintained at 1250~1150℃.

[0069] Step S2: The first combustion air nozzle 12 supplies combustion air into the furnace to maintain the temperature of the oxygen-excess combustion zone at 1100~1000℃.

[0070] Step S3 involves spraying water mist from coolant nozzle 13 to control the water content of flue gas to below 20%. Rapid cooling of the flue gas promotes the precipitation of salt ash in the form of microcrystalline particles, maintaining the primary cooling zone at 950~850℃.

[0071] Step S4 controls the cold air nozzle 14 to deliver air at a wind speed of 15-20m / s to keep the secondary cooling zone at 700~600℃.

[0072] On the other hand, such as Figure 7 As shown, corresponding to the above example, the present invention also provides a control method for a top-spray feeding high-temperature activation furnace, the example steps of which include:

[0073] Step S1: The fuel is mixed with combustion air and ignited by symmetrical tangential injection into the center circle 10 of the furnace through the fuel nozzle 11, forming the first swirling field in the furnace and controlling the reduction gasification zone to be maintained at 1250~1150℃.

[0074] Step S2: The incoming airflow of mixed livestock and poultry manure solid particles is sprayed symmetrically in a tangential circle to the inner diameter circle 25 of the manifold 21 through the spray pipe 22. The flow rate of the combustion air and the incoming airflow are controlled to form a differential speed, so that the incoming airflow flows into the outer annular gap of the central channel and forms a differential speed jacket state with the central channel. After the vortex and pulsating turbulent mixing of gas and solid are formed at the interface of the two fluid layers, the airflow is guided by the swirl blades 24 to the first swirl field for swirl spraying. The airflow diffuses at the adjacent furnace wall to form a return zone 3 that intersects with the first swirl field to suspend and guide the livestock and poultry manure solid particles.

[0075] Step S3: The first combustion air nozzle 12 supplies combustion air into the furnace to maintain the temperature of the oxygen-excess combustion zone at 1100~1000℃.

[0076] Step S4: The coolant nozzle 13 sprays water mist to control the water content of the flue gas to below 20%. Rapid cooling of the flue gas promotes the precipitation of salt ash in the form of microcrystalline particles, and keeps the primary cooling zone at 950~850℃.

[0077] Step S5 controls the cold air nozzle 14 to deliver air at a wind speed of 15-20m / s to keep the secondary cooling zone at 700~600℃.

[0078] In summary, the top-feed high-temperature activation furnace and its control method provided by this invention ingeniously design a vertical furnace body 1 structure to meet the gradient temperature field required for the activation of ash from solid particles of livestock and poultry manure. Simultaneously, through the specially designed fuel nozzle 11's opposing spray structure, a top-burning swirling flow field can be established within the furnace to generate sufficient centrifugal force. Combined with the top spray from the feed nozzle 2, this creates opposing airflows that generate strong turbulent disturbances in the central region of the furnace, improving the mixing efficiency of solid particles and high-temperature flue gas. This allows for the uniform radial distribution of micron-sized manure particles, while maintaining a stable axial flow velocity that balances with particle settling velocity. This resolves the contradiction between small particles escaping with the airflow and large particles settling too quickly, enabling solid particles to be dispersed in the strong swirling flow field. This avoids the formation of local dense phase zones in the furnace by large particles, ensuring that the activation temperature field in the reduction and gasification zone acts uniformly on particles of every size.

[0079] This achieves the goal of high-temperature activation of solid particles of livestock and poultry manure, providing the necessary conditions for the recovery of high-value elements such as phosphorus and potassium from ash.

[0080] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The present invention is limited only by the claims and their full scope and equivalents. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the invention should be included within the protection scope of the invention.

[0081] Furthermore, all or part of the steps in the methods of the above embodiments can be implemented by a program instructing related hardware. This program is stored in a storage medium and includes several instructions to cause a microcontroller, chip, or processor to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as a USB flash drive, a portable hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0082] Furthermore, various different implementations of the present invention can be combined arbitrarily, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed in the present invention.

Claims

1. A top-spray feeding high-temperature activation furnace, comprising: The vertical furnace body has fuel nozzles, first combustion air nozzles, coolant nozzles, and cold air nozzles arranged sequentially in the first, second, third, and fourth sections from top to bottom within the furnace chamber. These nozzles define a reduction gasification zone, an oxygen-overflow combustion zone, a primary cooling zone, and a secondary cooling zone within the furnace chamber for zoned temperature control. The fuel nozzles are arranged in pairs, forming a symmetrical tangential spray pattern around the center of the furnace chamber. This creates opposing airflows that generate turbulence and establish a first swirling flow field in the central region of the furnace chamber. The furnace top of the vertical furnace body has a feed nozzle that connects to the furnace chamber and sprays material towards the first swirling flow field, forming top combustion.

2. The top-spray feeding high-temperature activation furnace according to claim 1, wherein the feeding nozzle comprises: The system comprises a manifold, a propellant spray pipe, a combustion air pipe, and swirl vanes. The swirl vanes are located at the nozzle section within the manifold. The upstream section of the manifold is connected to the combustion air pipe to form a central flow channel filled with combustion air within the manifold. The propellant spray pipes are connected in pairs to the downstream section of the manifold, arranged in a symmetrical tangential spray pattern around the inner diameter of the manifold. The propellant sprays against the outer annular gap of the central flow channel, forming a differential speed jacket with the central flow channel. Guided by the swirl vanes, the propellant is sprayed into the first swirl field within the furnace and diffuses at adjacent furnace walls to form a return flow zone that intersects with the first swirl field.

3. The top-feed high-temperature activation furnace according to claim 2, wherein a neck is provided in the nozzle section downstream of the swirl blade in the manifold, and the neck connects the swirl blade to the nozzle of the manifold in a wavy-contracting shape.

4. The top-feed high-temperature activation furnace according to claim 2, wherein the manifold is provided with a water-cooled jacket layer, and the water-cooled jacket layer is connected to a pair of cooling water circulation nozzles.

5. The top-feed high-temperature activation furnace according to claim 1, wherein the temperature of each zone in the furnace chamber of the vertical furnace body is controlled according to the reaction temperature field as follows: reduction gasification zone 1250~1150℃, oxygen combustion zone 1100~1000℃, primary cooling zone 950~850℃, and secondary cooling zone 700~600℃.

6. The top-feed high-temperature activation furnace according to claim 1, wherein the coolant nozzles are arranged in a ring at intervals on the third section of the furnace, spraying water mist into the furnace to form a ring spray around the swirling flow field, and the rapid cooling of the flue gas causes the salt ash to precipitate in the form of microcrystalline particles, forming a density difference with the flue gas.

7. The top-feed high-temperature activation furnace according to claim 1, wherein the third section of the furnace chamber of the vertical furnace body is further provided with a denitrification agent nozzle, which is located below the coolant nozzle.

8. The top-spray feeding high-temperature activation furnace according to claim 1, further comprising: The ash collection device and the multi-pass membrane wall boiler are provided, wherein the multi-pass membrane wall boiler is connected to the vertical furnace body to receive waste heat recovery from flue gas, and the ash collection device is installed at the bottom of the vertical furnace body and the multi-pass membrane wall boiler to receive and recover settled ash.

9. A control method for a top-spray feeding high-temperature activation furnace as described in any one of claims 1 to 8, comprising the following steps: The fuel is mixed with combustion air and ignited by symmetrical tangential injection through fuel nozzles into the center circle of the furnace, forming the first swirling flow field inside the furnace. The solid particles of livestock and poultry manure are mixed with combustion air and sprayed into the top of the first swirl field through the feed nozzle, while the reduction and gasification zone is controlled to be maintained at 1250~1150℃. The first combustion air nozzle supplies combustion air into the furnace to maintain the temperature of the oxygen-excessive combustion zone at 1100~1000℃. The coolant nozzle sprays water mist to control the water content of the flue gas to below 20%. Rapid cooling of the flue gas promotes the precipitation of salt ash in the form of microcrystalline particles, and keeps the primary cooling zone at 950~850℃. Control the cold air nozzles to deliver air at a speed of 15-20 m / s, and keep the secondary cooling zone at 700~600℃.

10. A control method for a top-spray feeding high-temperature activation furnace as described in claim 2, comprising the following steps: The fuel is mixed with combustion air and ignited by symmetrical tangential injection into the center circle of the furnace through fuel nozzles, forming the first swirling flow field in the furnace and controlling the reduction gasification zone to maintain 1250~1150℃. The incoming airflow, which is mixed with solid particles of livestock and poultry manure, is sprayed symmetrically in a tangential circle into the inner diameter of the manifold through the spray pipe. The flow rate of the combustion air and the incoming airflow are controlled to form a speed difference, so that the incoming airflow flows into the outer annular gap of the central flow channel and forms a speed difference jacket state with the central flow channel. After the vortex and pulsating turbulence are formed at the interface of the two fluid layers, the mixture of gas and solid is sprayed into the first swirl field through the swirl blades and diffuses at the adjacent furnace wall to form a return flow zone that intersects with the first swirl field. The first combustion air nozzle supplies combustion air into the furnace to maintain the temperature of the oxygen-excessive combustion zone at 1100~1000℃. The coolant nozzle sprays water mist to control the water content of the flue gas to below 20%. Rapid cooling of the flue gas promotes the precipitation of salt ash in the form of microcrystalline particles, and keeps the primary cooling zone at 950~850℃. Control the cold air nozzles to deliver air at a speed of 15-20 m / s, and keep the secondary cooling zone at 700~600℃.

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