A spray gun, a fluidized calciner and a control method thereof

Abstract

The application discloses a spray gun, a fluidized calcination furnace and a control method thereof, and relates to an intelligent lateral pulse disturbance system applied to a zinc concentrate fluidized calcination process. The system is implanted with a vectorized oblique downward pulse device on the side wall of the furnace body, utilizes the rebound jet effect after the high-pressure airflow touches the ground and the shock wave expansion in the limited space, eliminates the fluidized dead angle around the distribution plate, and breaks the initial agglomerates generated by the sudden heating of the water-containing concentrate entering the furnace in the feed inlet area. In cooperation with a closed-loop control strategy based on the temperature-pressure space-time coupling (qualitative full-furnace pressure and local temperature positioning), the system can overcome the energy shielding effect of the high-resistance distribution plate on the bottom pulse, realizes accurate targeted management without damaging the negative pressure environment in the furnace, and significantly prolongs the continuous operation cycle of the calcination furnace.

Description

Technical Field

[0001] This invention relates to the field of non-ferrous metal metallurgy, and more particularly to a spray gun, a fluidized bed roasting furnace, and a control method thereof. Background Technology

[0002] 1. Fluidized bed roasting process for zinc concentrate

[0003] Fluidized bed roasting of zinc concentrate is a crucial step in modern zinc hydrometallurgical processes, and its operational efficiency directly determines the overall capacity, leaching rate, and total recovery rate of the smelter. The core objective of this process is to oxidize zinc sulfide (ZnS) concentrate into zinc oxide (ZnO) roast, which is readily soluble in dilute sulfuric acid, under high temperature (typically controlled at 900℃~1000℃) and excess air coefficient (typically 1.2~1.3) conditions through intense gas-solid contact.

[0004] The main chemical reactions are as follows:

[0005]

[0006] The reaction process takes place in a fluidized bed roasting furnace, a typical high-density dense phase fluidized bed. Air is drawn into the furnace from a high-pressure centrifugal blower or a Roots blower via a bottom bellows, passing through a gas distribution plate with thousands or even tens of thousands of mushroom-shaped air caps, depending on the furnace bed area. The high-speed airflow drives the furnace to a height of 0.8m to 1.5m, with a bulk density of approximately [missing information]. The mineral particle bed is in a suspended fluidized combustion state.

[0007] In this process, the particles are not only reactants but also heat carriers. Heat and mass transfer within the bed is extremely intense, with a heat transfer coefficient reaching [value missing]. To ensure desulfurization efficiency, frequent exchange between the emulsion phase and the bubble phase in the bed must be maintained. However, once this exchange is disrupted, it will trigger a series of cascading failures.

[0008] 2. Industry Pain Points

[0009] Although fluidized bed roasting technology has been used for many years, it still faces challenges in processing increasingly complex zinc concentrate feedstocks (such as those with high impurities). Even at this stage, loss of flow remains a persistent problem in the industry. Its microscopic and macroscopic mechanisms are extremely complex:

[0010] The mechanism of caking and agglomeration of water-containing furnace charge in the feed area due to sudden heating at high temperature: Industrial zinc concentrate typically contains 8% to 12% physical water. When the wet and cold concentrate enters the high-temperature furnace at 950°C through the top feeder, the moisture on the surface of the particles evaporates instantly due to the heat.

[0011] If the local fluidization velocity below the feed inlet is insufficient, the vapor film generated by water evaporation will temporarily coat the particles, hindering oxygen contact.

[0012] Before the moisture evaporates completely, the trace liquid film on the surface of the mineral particles will use capillary pressure and surface tension to quickly adhere the fine particles together, forming primary wet aggregates.

[0013] The density and equivalent diameter of these aggregates increase instantaneously, and their terminal settling velocity ( ) far exceeding the apparent gas velocity of the bed ( According to Stokes' Law and the principle of fluidized bed sorting, they will quickly penetrate the fluidized bed and settle onto the surface of the gas distribution plate. Once landed, these agglomerates will detach from the main fluidized heat transfer zone and become the nuclei for subsequent high-temperature sintering.

[0014] Zinc concentrate often contains impurities such as lead (Pb), copper (Cu), iron (Fe), and silicon dioxide (SiO2). In poorly fluidized areas such as the furnace wall edges and dead corners of the distribution plate, the gas-solid contact efficiency is low, resulting in insufficient local oxygen partial pressure (reducing atmosphere) and low temperature (e.g., <850℃).

[0015] Under these conditions, low-melting-point eutectic compound systems are readily formed. For example, lead sulfide (PbS) can form complex lead silicate salts with lead oxide (PbO) and silicon dioxide (SiO2), and their eutectic melting points can be as low as 700℃~750℃.

[0016] In areas of alternating localized overheating or oxygen deficiency, iron oxide and zinc oxide readily form zinc ferrite with a spinel structure. This is a substance that is poorly soluble in acid and easily causes particles to stick together.

[0017] These liquid or semi-molten phase substances act as high-temperature binders between particles, promoting neck growth at the contact points between particles, and ultimately cementing the loose mineral particles into hard lumps.

[0018] Once initial agglomeration forms on the distribution plate, the air caps in that area will be blocked, or the vertical airflow will be deflected by the agglomeration. This leads to a further reduction in fluidizing airflow and a further decrease in temperature in that area, which in turn accelerates the formation of cryogenic eutectics and the expansion of the agglomeration range. Ultimately, this will cause an abnormally high pressure drop in the furnace bed, resulting in severe airflow deviation and forcing the system to be shut down for manual cleaning.

[0019] 3. Existing technical processing methods and their in-depth engineering defect analysis

[0020] In order to maintain production, existing technologies have been forced to adopt passive measures, but all of them have fundamental flaws in their physical principles:

[0021] One of the mainstream methods currently used in the industry is manual furnace poking, which carries high risks and thermodynamic damage. Operators must wear heavy protective clothing, open the observation hole on the side wall of the furnace, and blindly poke inside the furnace using a steel rod or high-pressure air hose that is several meters long.

[0022] The boiling furnace must be under slight negative pressure The furnace is running at a lower temperature. The instant the furnace door is opened, the huge pressure difference causes a large amount of cold air from the outside to be drawn in. This not only causes a sudden drop in furnace temperature... It disrupts combustion stability, and more fatally, it dilutes the smoke. Concentration. For downstream acid converters, drastic fluctuations in flue gas concentration (e.g., a sudden drop from 12% to 8%) can cause runaway temperature in the vanadium catalyst layer, severely affecting conversion rate and exhaust emission indicators.

[0023] Manual operation is limited by the length and weight of the steel rod and its softening properties at high temperatures, and can usually only handle surface clumps within a 1m radius around the furnace wall. For stubborn dead spots in the center of the furnace or deep under the distribution plate (depth > 1.5m), manual labor is woefully inadequate.

[0024] Operators are directly exposed to high-temperature radiation, dust, and toxic fumes. In a steam environment, if a material collapse occurs inside the furnace, causing a sudden positive pressure backlash, it can easily lead to serious personal injury accidents.

[0025] The second approach involves bottom pulse and hydrodynamic impedance mismatch. Some studies have attempted to adapt bottom pulse airflow technology from the light industry and pharmaceutical sector to zinc roasting furnaces, by installing high-pressure nozzles at the bottom of the air chamber to blow air upwards through the distribution plate.

[0026] Unlike the high-aperture distribution plate of a dilute phase fluidized bed, the zinc roasting furnace has an extremely low aperture ratio (typically <3%) in its air cap plate to ensure uniform air distribution across a large diameter (>10m) cross-section. Furthermore, the air cap is designed with a complex labyrinth structure to prevent material leakage. From a fluid dynamics perspective, the distribution plate is a large, highly damped element.

[0027] According to compressible fluid dynamics, the high-pressure energy of the bottom pulse is mostly consumed in: (1) filling the huge free volume (dead zone volume) of the bellows; (2) overcoming the frictional resistance of the narrow flow channel of the bellows; and (3) turbulent dissipation of the airflow in the bellows. The remaining kinetic energy reaching the bottom of the bed is insufficient to destroy the sintered solid bridge.

[0028] To force penetration, extremely high pulse pressure (>0.8MPa) is often required. This high-frequency, high-intensity shock wave acts directly on the refractory castable on the lower surface of the distribution plate, which can easily cause micro-cracks in the refractory layer and eventually cause it to peel off, or even cause fatigue fracture of the wind cap fixing bolts, leading to catastrophic material leakage accidents.

[0029] 4. Technical bias in this field

[0030] In the engineering design of fluidized bed roasting furnaces for zinc concentrate, engineers have long held a strong aversion to lateral auxiliary flow, forming a deep-rooted technical bias. This bias is mainly based on considerations of the following three engineering risks: Damage to the fluidized bed ring-core structure: Traditional theory holds that large fluidized beds must maintain a strictly vertical upward gas-solid flow pattern, i.e., a ring-core structure with rising central airflow and descending wall material. Engineers generally believe that laterally introduced airflow will disrupt this circulation, leading to local airflow short-circuiting or channeling, thereby disrupting the overall homogeneity of the bed and affecting desulfurization efficiency. Wall erosion and thermal shock spalling risks (deep explanation of wear): This is the most significant concern in the industry. Engineering experience shows that introducing horizontal or near-horizontal high-speed jets into the fluidized bed will produce severe jet penetration effects. Mechanical wear: High-speed airflow will entrain high-hardness zinc roasting sand particles in the bed, forming a high-momentum abrasive flow. If the airflow is not completely dissipated by the bed and directly impacts the opposite furnace wall, it will cause severe localized erosion wear. Thermal stress damage: More critically, the air blown in laterally is typically at a lower temperature (approximately 20-50°C), while the refractory bricks in the furnace wall are at a high temperature (approximately 950°C). Continuous or frequent lateral airflow impacts can cause severe periodic temperature gradients on the surface of the refractory material on the opposite side, triggering thermal shock and leading to cracking or even lamellar spalling of the refractory bricks. Therefore, conventional designs strictly prohibit direct lateral airflow from scouring the furnace wall to protect the furnace lining's lifespan. It is generally believed that the additional kinetic energy of the lateral airflow can easily lead to excessive bubble coalescence, inducing swelling in the bed. The bursting of large bubbles not only causes violent fluctuations in bed pressure but also significantly increases the entrainment of fine dust, exacerbating the load on subsequent waste heat boilers and dust collection systems. Due to these technical biases, existing zinc roasting furnace designs have always been limited to bottom-inlet modes, lacking mature and reliable lateral auxiliary fluidization devices.

[0031] Although some solutions for clearing blockages by installing nozzles on the sidewalls of fluidized bed furnaces have emerged in the prior art (such as Chinese patent application with publication number CN119394022A), these solutions usually have serious defects in engineering applicability:

[0032] 1. Existing technology claims to adjust the nozzle direction to align with the orifice area. However, the distribution plate of an industrial-grade zinc roasting furnace is densely covered with thousands of air cap orifices, and the limited number of nozzles on the side walls simply cannot achieve precise alignment with specific orifices. More importantly, during fluidized bed furnace operation, a 1.0~1.5m thick high-density dense phase particle layer covers the distribution plate. This bed layer constitutes a huge gas-solid shield, causing the momentum of the lateral jet to be completely dissipated by the high-concentration particle flow before reaching the orifice in the central area, making the so-called aligned clearing hydrodynamically impossible.

[0033] 2. Existing technologies typically involve fixing the nozzle in place and exposing it to the furnace interior for extended periods. Within the boiling layer, the high-speed moving zinc concentrate particles cause severe scouring and wear on the nozzle, leading to perforation and failure within weeks. Furthermore, prolonged exposure to a high-temperature environment of 950°C can easily cause creep deformation of the nozzle material.

[0034] 3. Existing solutions often employ long-duration blowing strategies (e.g., continuous blowing for 10 or even 15 seconds). For applications requiring strictly maintained low negative pressure... In a zinc concentrate fluidized bed roasting furnace in operation, prolonged high-pressure gas injection can cause a sudden surge in furnace pressure, turning it into positive pressure, disrupting the pressure balance, and leading to flue gas overflow or even a positive pressure flameout accident.

[0035] 4. Existing solutions attempt to directly mount temperature or pressure sensors on the surface of a high-temperature gas distribution plate. However, because the distribution plate operates at 950°C and is subjected to severe particle erosion, the sensors are highly susceptible to damage, preventing the system from operating stably for extended periods.

[0036] 5. For the 15s continuous injection scheme proposed in existing technologies (such as Chinese patent application publication number CN119394022A), theoretical calculations are performed based on the gas critical flow formula:

[0037] Gas source pressure P0 = 0.8 MPa, nozzle diameter d = 30 mm, furnace temperature T furnace =950℃.

[0038] Since P0 > 0.19 MPa (critical pressure), choked flow occurs at the nozzle, and the mass flow rate m is approximately 2.5 kg / s.

[0039] When the injected cold air (20°C) enters the 950°C furnace, its volume expands by about 4.2 times instantly.

[0040] The existing technology (15s) uses a single injection to inject a total gas volume into the furnace, which is equivalent to approximately 190m³ of the furnace's hot volume. 3 For 38m 2 A boiling furnace, which is equivalent to adding an extra 12m in 15 seconds. 3 The instantaneous flow rate is / s. Since the frequency conversion regulation response of industrial induced draft fans is usually 5~10s, the fan cannot remove the sudden increase in flow rate in time, which will inevitably cause the furnace top pressure to exceed 0pa, resulting in severe positive pressure flame ejection. Summary of the Invention

[0041] The present invention aims to provide a spray gun, a fluidized bed roasting furnace and its control method, which overcomes the energy shielding effect of the high resistance distribution plate on the bottom pulse in the fluidized bed roasting furnace, and achieves precise targeted treatment without disrupting the negative pressure environment inside the furnace, thereby significantly extending the continuous operation cycle of the roasting furnace.

[0042] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0043] A spray gun includes a housing containing an internal connecting cavity. One end of the housing is fitted with a sealing flange. The main pipe of the spray gun passes through the sealing flange and is inserted into the internal connecting cavity of the housing. One branch opening of the housing is connected to an instrument air inlet pipe. A ball-shaped cavity is provided in the housing, which is located downstream of the air inlet of the instrument air inlet pipe. The ball-shaped cavity contains a ceramic ball, the diameter of which is larger than the diameter of the internal connecting cavity.

[0044] The ceramic spheres are preferably silicon nitride ceramic spheres.

[0045] The spray gun of this invention can achieve pulse jet spraying inside the furnace. The spherical cavity and silicon nitride ceramic ball are installed at the opening in the furnace wall, and gravity sealing is achieved through the silicon nitride ceramic ball. In the sealed state: when the spray gun retracts, the silicon nitride ceramic ball falls into the connection between the internal connecting cavity and the spherical cavity of the shell under the action of gravity and the furnace pressure, physically preventing the furnace gas from escaping. In the working state: when the spray gun extends, the guide surface of the spray gun head pushes the ceramic ball into the upper spherical cavity, opening the spray channel. Normal sealing gas: a small amount of compressed air (flow rate <5nm) is introduced downstream (upstream) of the sealing ball valve (silicon nitride ceramic ball). 3 / h), maintaining positive pressure in the valve chamber to prevent dust backflow from the furnace and jamming the ball valve. Pneumatic / electric telescopic thruster: linked with the PLC, used to drive the spray gun to quickly pass through the valve body and enter the furnace (stroke 200-400mm).

[0046] Preferably, the spherical cavity is disposed on the upper surface of the housing. The spherical cavity is configured as an inverted U-shape, and the lower side of the inverted U-shape is sealed to the housing.

[0047] In one preferred embodiment, the outlet end of the spray gun main pipe is frustum-shaped, and the diameter of the outlet end is smaller than the diameter of the other parts. The diameter of the outlet end of the spray gun main pipe is Φ28~30mm.

[0048] The main pipe of the spray gun has a size of Φ (50~60mm)×3.5. The constriction design at the outlet of the main pipe of the spray gun ensures that the airflow at the outlet reaches the speed of sound (Mach 1) under the gas source pressure of 0.6~0.8MPa and generates a sub-expansion supersonic jet in the furnace. At the same time, it limits the instantaneous gas consumption of a single pulse, prevents the pressure of the gas storage tank from dropping too quickly, and ensures the energy consistency of continuous pulses.

[0049] In one preferred embodiment, an electromagnetic pulse valve is mounted on one end of the housing.

[0050] The present invention also discloses a fluidized bed roasting furnace, including a mounting base installed in the fluidized bed roasting furnace, wherein the mounting base is equipped with the spray gun, the spray gun is a pulse spray gun, and the spray gun is set obliquely downward at an angle θ to the horizontal plane, where 30°≤θ≤60°.

[0051] This invention avoids the high-resistance distribution plate directly acting on the dead corner in space, and uses extremely short pulses in time to avoid disrupting the steady-state flow field, thus achieving a perfect balance between clearing blockages and maintaining stable production.

[0052] The spray gun's axis is not set horizontally, but rather inserted obliquely downwards at an angle θ to the horizontal plane, where 30° ≤ θ ≤ 60°. The vertical component (F) y The rebound effect generates a downward impact force. According to aerodynamic jet theory, after the high-pressure airflow impacts the rigid distribution plate (or the deposits on the plate), a momentum-conserving reflection occurs, forming an upward secondary jet. This bottom-up rebound force can forcibly lift the material deposited on the plate surface and throw it into the upper active fluidization zone. Horizontal component (F) x The shearing and sweeping action generates tangential shear force, which pushes the bottom material to move laterally, breaks the static friction accumulation angle at the dead corner, promotes the horizontal mixing of bottom particles, and eliminates the radial temperature gradient.

[0053] In one preferred embodiment, the height h of the spray gun outlet from the upper surface of the gas distribution plate is 300mm to 600mm; preferably 300mm to 500mm.

[0054] The spray gun outlet is located 300mm to 600mm above the gas distribution plate. This height is chosen based on the axial density distribution characteristics of the fluidized bed. This area belongs to the high-density deposition zone at the bottom of the fluidized bed, where agglomerates are most likely to settle and accumulate. Simultaneously, this height is higher than the mechanical height of the bottom air cap (approximately 200-300mm), preventing physical interference or thermal expansion compression between the spray gun and the air cap.

[0055] The mounting base is installed in an area 400mm to 600mm above the gas distribution plate.

[0056] In one preferred embodiment, the mounting base is provided with a constant air inlet, which is connected to the air inlet of the instrument air intake pipe.

[0057] Preferably, the mounting base is a water-cooled mounting base.

[0058] Preferably, the mounting base and the spray gun housing are fixedly connected by a connecting flange.

[0059] Preferably, for the high temperature (950℃), high abrasion (fluidized scouring) and strong corrosion (alternating sulfidation / oxidation atmosphere) environment inside the furnace, the pulse jet device mainly consists of a high temperature and wear-resistant spray gun, a connecting flange and supporting pipelines.

[0060] Considering the high temperature of approximately 950°C and the corrosive sulfide environment inside the furnace, the spray gun is made of high-temperature resistant alloy materials (such as nickel-based alloys or heat-resistant stainless steel). To prevent dust entrained by the high-speed airflow from causing wear on the pipe wall, the spray gun head can be fitted with a ceramic wear-resistant lining (such as silicon carbide or alumina) or have its surface hardened as needed.

[0061] The spray gun adopts a natural air cooling or a simple water cooling jacket structure (depending on the furnace temperature). A micro-positive pressure protective air passage is provided at the tail of the spray gun, which continuously introduces a small amount of clean air during the pulse interval to form an air curtain, preventing flue gas and dust from the furnace from flowing back into the spray gun.

[0062] The spray gun is installed at the opening on the side wall of the furnace body through a sealing flange. The flange connection is equipped with a flexible compensation structure (such as a bellows or asbestos gasket) to absorb thermal expansion displacement under high temperature.

[0063] Preferably, the spray guns are installed in multiple sets, preferably 6 to 10 sets. It includes a standard cleaning unit and a feeding enhancement unit. The standard cleaning unit includes 4 to 8 sets of spray guns, with a spray gun insertion length of 200-400 mm. The feeding enhancement unit includes 1 to 3 sets of spray guns, with a spray gun insertion length of 200-300 mm.

[0064] The present invention also discloses an anti-caking control method for a fluidized bed roasting furnace. When the fluidized bed roasting furnace pressure warning is issued and the abnormal temperature point is successfully located, a high-pressure pulse airflow is sprayed from the spray gun toward the bottom of the fluidized bed roasting furnace. The high-pressure pulse airflow is inclined downward at an angle θ with the horizontal plane, 30°≤θ≤60°, so that the airflow rebounding through the bottom of the fluidized bed roasting furnace activates the abnormal temperature point until the temperature of the abnormal temperature point rises.

[0065] When the pressure warning of the fluidized bed roasting furnace is issued and the temperature distribution is uniform, start the full furnace wheel injection in the diagonal sequence of the fluidized bed roasting furnace to break the critical state through all-round disturbance.

[0066] In one preferred embodiment, the pressure of the high-pressure pulsed airflow is 0.6~0.8MPa, the single-purge time is 100ms~500ms, and the purge interval is 1~2s.

[0067] When high-pressure gas (0.6~0.8MPa) enters a low-pressure bed (0.01MPa), its volume expands tens of times within milliseconds. Within the downward-sloping confined space (particle gaps), this expansion generates shock waves similar to miniature explosions, effectively shattering the solid bridges between particles.

[0068] In one preferred embodiment, the pressure warning method is to use high-frequency pressure sensors installed in the wind chamber and furnace top to calculate the high-order statistics of the pressure difference signal of the entire furnace bed in real time, which is used to determine whether the fluidization state of the entire furnace has deteriorated. The deterioration of the fluidization state of the entire furnace is a pressure warning.

[0069] Preferably, the higher-order statistics of the total furnace bed pressure difference signal are the standard deviations of the total furnace bed pressure difference signal, specifically:

[0070] Standard deviation criterion: Calculate the standard deviation σ of ΔP using a preset time sliding window;

[0071] When σ < 150 Pa, the bed is judged to have a tendency to freeze or become dead.

[0072] When σ>400Pa, it is determined that an overall slug in the bed has occurred.

[0073] The preset time is 30~180s, preferably 30~90s.

[0074] Preferably, the sampling rate of the high-frequency pressure sensor is 100~150Hz.

[0075] In one preferred embodiment, the temperature T of each zone is calculated in real time. i With the average temperature of the entire furnace T avg Deviation value D evi When a certain partition deviation D evi When the temperature is below -20℃, the zone is identified as a temperature anomaly.

[0076] D evi -20℃ is lower than the average temperature of the entire furnace (T). avg 20℃.

[0077] This system is not merely an actuator; it also incorporates an intelligent decision-making algorithm based on the fusion of fluid dynamics and thermodynamic characteristics. Given the strong overall characteristics and weak local characteristics of pressure signals in large fluidized beds, this system employs a dual-detection logic global fluidization quality characterization algorithm (time dimension—qualitative early warning) that uses pressure for qualitative analysis (determining whether an anomaly is present) and temperature for localization (determining the location of the anomaly).

[0078] Targeted burst mode: Triggered when pressure warning is issued and temperature positioning is successful. The system only executes high-frequency continuous firing (interval of 1~2s) on the electromagnetic pulse valve corresponding to the abnormal temperature point, using a powerful shock wave to activate the dead zone at the precise point until the temperature at that point rises again.

[0079] Blind Zone Patrol Mode: Triggered when pressure warning is issued but temperature distribution is uniform (unable to pinpoint location). The system determines that the entire furnace is at critical caking and automatically initiates a full-furnace patrol injection in a diagonal sequence (e.g., 1#→5#→3#→7#...) to break the critical state through omnidirectional disturbance.

[0080] Feed protection mode: Independent logic. As long as a sharp drop in the rate of change of thermocouple temperature dT / dt below the feed inlet is detected (e.g., >5℃ / min), the enhanced pulse unit below the feed inlet is immediately activated, regardless of the total pressure signal, to prevent wet material accumulation.

[0081] An independent high-pressure gas storage tank (0.6~0.8MPa) is used, unlike the low-pressure (<0.05MPa) high-flow main fan. High-frequency continuous pulse valves (1~2s intervals) are used to activate the dead zone at the temperature anomaly point using a powerful shock wave. Once the agglomerates are broken up, the injection is immediately stopped, and the main bed airflow re-establishes fluidization, allowing the local temperature at the anomaly point to naturally recover within 3~5 minutes through gas-solid heat exchange. A high-frequency three-pulse sequence injection is preferred, with a single pulse width of 300ms and a pulse interval of 1s, utilizing the superimposed shock waves to dissipate the agglomerates. After completing one pulse sequence, the spray gun retracts, and the system is forced into a 45~60s observation period. During this period, the PLC stops the injection action in that area, monitoring the transient changes in global air pressure and airflow, as well as the recovery of the gas storage tank pressure. If the agglomerates are successfully broken up within the evaluation period, the bed resistance in that area is released instantaneously, which will macroscopically manifest as a shift in the operating point of the system's piping characteristics. If a sudden drop in total air pressure in the air chamber is detected (e.g., a drop of >300 Pa), and / or accompanied by a transient increase in total system airflow, the system determines that the pulsed shock wave has successfully penetrated the dead zone. The pulse operation is immediately terminated, allowing the main bed airflow to complete the subsequent slow heat mixing on its own. If there are no significant signs of improvement in total airflow and air pressure during the evaluation period, indicating that the agglomeration is extremely stubborn and the fluidization dead zone still exists, the system will trigger another round of high-frequency triple pulse sequence.

[0082] Monitor the main frequency offset to help determine the fluidization quality.

[0083] A furnace internal temperature field mapping was constructed using multiple armored thermocouples (TE-01 to TE-08) distributed circumferentially above the pulse jet lance. The temperature T in each zone was calculated in real time. i With the average temperature of the entire furnace T avg Deviation value D evi .

[0084] Because gas-solid exchange ceases and exothermic reactions terminate in the dead bed region, its temperature is typically significantly lower than that of the active region. When a certain partition deviation D... evi When the temperature is below -20℃ (i.e., below the average temperature of 20℃), the system identifies that location (e.g., sector #3) as a suspected clumping area.

[0085] The mechanical impact force generated by the high energy density released in an extremely short time breaks up agglomerates. Although the instantaneous power is extremely high, the total amount of gas released in a single pulse is very small relative to the total volume of the furnace (<0.1%) due to the extremely short pulse. Therefore, the pulse action does not cause macroscopic fluctuations in the furnace pressure, nor does it disrupt the negative pressure balance inside the furnace, thus ensuring the stable operation of the subsequent acid production system.

[0086] The extremely short blowing time means that the cumulative scouring time of the jet airflow on the opposite side furnace wall is very short (only a few seconds per day), thus fundamentally solving the problem of traditional side-blowing air abrasion of the furnace lining.

[0087] Compared with Chinese patent application CN119394022A, this invention provides an intelligent anti-caking system, including the telescopic self-sealing spray gun of this invention and an anti-caking control method for a fluidized bed roasting furnace. This invention abandons the erroneous approach of directly using a large airflow to purge small orifices in the prior art, and instead adopts a mechanism of pulsed airflow oscillating the bed.

[0088] Compared with the prior art, the beneficial effects of the present invention are:

[0089] 1. In order to solve the problem of spray gun wear, this invention designs a dynamic working mode that retracts and seals under normal conditions and extends for operation in abnormal situations.

[0090] The overall structure is installed at an angle θ (30-60°) downwards. Addressing the problem of dense-phase beds hindering airflow penetration, this invention utilizes the rebound effect of a high-pressure jet impacting the dead zone at the furnace bottom, creating a strong turbulent field in a localized area. Regardless of the location of the orifice, as long as it is within the sector covered by the rebound flow field, the deposits will be entrained and thrown up.

[0091] The spray gun is installed 300-600mm above the gas distribution plate. Based on simulation results of 300mm×300mm slices, the volume fraction of bed material shows a clear inflection point at a height of 0.6m (decreases from 0.6 to 0.35 and tends to stabilize). Setting the spray gun below 0.6m ensures that the jet energy is concentrated on the high-density dead zone, while avoiding insufficient coverage due to excessively low height. 2. This invention employs micro-disturbance control, with the single injection time strictly controlled within 100-500 ms. The pressure wave generated by the instantaneous gas release propagates rapidly in the dense phase bed, and the resulting transient shear force disrupts the solid bridges and van der Waals forces between the caking materials, loosening the material in the dead zone. The high-speed jet following the shock wave impacts the bottom of the dead zone and rebounds, forming an upward entrainment flow field that rapidly transports the loosened material to the upper fluidized zone, preventing it from re-accumulating in place. This invention utilizes the synergistic effect of these two airflow actions.

[0092] Since the blowing time is much shorter than the response time constant of the frequency conversion adjustment of the exhaust fan, and the total air supply is extremely small, the present invention will not cause macroscopic fluctuations in the furnace top pressure during the unblocking process, thus completely eliminating the positive pressure flameout hazard caused by the existing technology (long-time blowing).

[0093] 3. This invention employs a sidewall thermocouple array combined with a high-frequency pressure sensor in the wind chamber / furnace top for indirect state inference. It uses a strategy of pressure qualitative assessment (determining the overall furnace health) and temperature location (locking down the faulty sector).

[0094] The single-injection hot volume of this invention is only 3.8m³. 3 The trace amount of gas only causes millisecond-level fluctuations (shock waves) in the furnace pressure, which are then suppressed by the negative pressure system and remain completely within the safe control range. Attached Figure Description

[0095] Figure 1 This is a diagram showing the overall installation location and system process flow of an industrial zinc concentrate fluidized bed roasting furnace in one embodiment of the present invention. The diagram shows an independent gas source station, a PLC control cabinet, a ring-shaped distribution pipeline network surrounding the furnace body, and a uniformly distributed spray gun arrangement.

[0096] Figure 2 This is a top view of the pressure distribution plate.

[0097] Figure 3 This is a diagram showing the insertion position of the spray gun.

[0098] Figure 4 This is an enlarged schematic diagram of the spray gun's structure.

[0099] Figure 5 This is a schematic diagram of the structure of one embodiment of the present invention, in which the spray gun is in the inlet position and the ball is located in the ball-containing cavity.

[0100] Figure 6 This is a schematic diagram of the structure of one embodiment of the present invention. The spray gun is in the retracted position, and the ball falls and naturally seals the pipe.

[0101] Figure 7 This is a block diagram illustrating the principle logic of a control method in one embodiment of the present invention.

[0102] Figure 8 It is a fluid motion diagram based on existing technology.

[0103] Figure 9 This is a fluid motion diagram in one embodiment of the present invention.

[0104] Figure 10 This is a schematic diagram of a fluidized bed gas-solid numerical simulation in one embodiment of the present invention, wherein the mass fraction of solids at the bottom of the bed is greater than 55%.

[0105] Figure 11This is a simplified model of local gas-solid two-phase flow in a 1m initial particle bed in one embodiment of the present invention (θ is 60°).

[0106] Figure 12 This is a simplified model of local gas-solid two-phase flow in a 1m initial particle bed in one embodiment of the present invention (θ is 30°).

[0107] Figure 13 This is a simplified model of local gas-solid two-phase flow in a 1m initial particle bed in one embodiment of the present invention (θ is 45°).

[0108] Figure 14 In one embodiment of the present invention, a 300×300mm local slice model is used to perform numerical simulation of particle flow in a 1m bed.

[0109] Figure 15 This is a numerical simulation result of particle flow in a 1m bed using a 300×300mm local slice model in one embodiment of the present invention (height selected).

[0110] Figure 16 This is a numerical simulation result of particle flow in a 1m bed using a 300×300mm local slice model in one embodiment of the present invention (orientation selection).

[0111] In the diagram:

[0112] 1. Spray gun, 2. Mounting base, 3. Connecting flange, 4. Normal blowing air inlet, 5. Electromagnetic pulse valve, 6. Pulse air inlet, 7. 1m high fluidized bed, 8. Pressure distribution plate, 9. Perforated air cap on the distribution plate, 10. Feed port for boiling furnace;

[0113] 11 Spray gun main pipe, 12 housing, 13 ceramic ball, 14 instrument air inlet pipe, 15 sealing flange, 16 ball cavity, 17 outlet end;

[0114] Among them, 1 - spray gun: made of high temperature resistant alloy, with wear-resistant inner lining, inserted into the furnace at an angle downward;

[0115] 2 — Mounting base: welded to the outside of the furnace body steel shell, with a cooling water chamber inside to protect the connection parts and sealing gaskets;

[0116] 3 — Connecting flange: Used to fix the pulse spray gun to the mounting base for easy disassembly and maintenance;

[0117] 4 — Constant air inlet: The constant air inlet at the tail of the spray gun is connected to the factory's instrument air duct network via a check valve. This effectively prevents condensation, scaling, and nozzle blockage caused by backflow of humid flue gas from the furnace.

[0118] 5 — Electromagnetic pulse valve;

[0119] 6 — Pulse Inlet: Connects to the high-pressure gas storage tank and the electromagnetic pulse valve, used for inputting instantaneous high-pressure gas.

[0120] Figure 3 In the diagram, #1 to #8 represent the insertion positions for the eight pulse spray guns. Detailed Implementation

[0121] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other. For ease of description, the terms "upper," "lower," "left," and "right" used below only indicate that they correspond to the upper, lower, left, and right directions in the accompanying drawings and do not limit the structure.

[0122] Example 1: Construction of a new 109m 2 Anti-caking system configuration for large fluidized bed furnaces

[0123] 1. Basic parameters of the roasting furnace

[0124] 109m 2 Fluidized bed roasting furnace, furnace inner diameter Φ11.8m. Daily processing capacity of 800 tons of zinc concentrate, fluidized bed height of 1m, operating temperature of 950℃.

[0125] 2. Detailed System Configuration

[0126] like Figure 1-3 As shown, eight sets of lateral pulse injection devices are evenly distributed along the circumference of the furnace body. The vertical height of the nozzle outlet centerline from the upper surface of the gas distribution plate is set to 400mm. This height has been optimized through fluid simulation and is exactly at the optimal balance point between the effective penetration depth of the jet and avoiding interference from the wind cap.

[0127] Standard cleaning unit (6 sets), the angle between the spray gun axis and the horizontal plane is θ=45°.

[0128] Two sets of feed enhancement units are located on the left and right sides directly below the main feed inlet (1.5m apart), with the angle adjusted to... Furthermore, the spray gun insertion length is shortened. This arrangement is designed to generate a stronger vertical downward impact component, specifically targeting and blasting high-moisture, high-density agglomerates at the feed point.

[0129] outer tube adopts Inconel 625 seamless tubing.

[0130] Internal inlay The nozzle tube is made of recrystallized silicon carbide (R-SiC) with a diameter between it and a high-temperature ceramic fiber felt to buffer the difference in thermal expansion.

[0131] A flexible graphite metal spiral wound gasket is used to seal between the spray gun and the furnace shell flange, and a bellows expansion joint is installed to compensate for axial thermal expansion (expected expansion amount is about 10mm).

[0132] Each spray gun has a constant air inlet at its tail, which connects to the factory's instrument air system. A flow meter controls the constant air volume. Ensure that the nozzle flow rate is greater than [a certain value] during the pulse valve closure period. (Higher than the suspension velocity of the particles) to prevent dust backflow caused by positive pressure fluctuations in the furnace.

[0133] 3. Intelligent control logic and operation process

[0134] The system is integrated into the plant's DCS (Distributed Control System), and the logic is as follows (see...). Figure 7 ):

[0135] Sampling and Calculation:

[0136] DCS with High-frequency sampling rate for collecting air chamber pressure and furnace top pressure .

[0137] Calculate real-time bed pressure difference (in (This is a correction term to deduct the wind resistance of the distribution plate). The theoretical pressure drop of the distribution plate is calculated based on the orifice plate throttling principle in fluid mechanics. Gas loses some pressure as it passes through the small orifice (ventilation cap). This pressure loss is proportional to the square of the gas flow rate Q. K is the inherent resistance constant of the distribution plate, determined by the orifice ratio, orifice diameter, structure, and other physical properties of the ventilation cap.

[0138] The PLC performs a sliding window calculation every minute to obtain the standard deviation σ of ΔP over the past 60 seconds.

[0139] Triggering condition determination:

[0140] 1. Fluidization deterioration: When The normal value is The left and right positions indicate the presence of channeling or unstable swelling in the bed.

[0141] 2. Dead Bed Warning: When the thermocouple temperature in the feed inlet area... And this trend lasted for more than 2 minutes.

[0142] 3. Manual instructions: Operators manually trigger instructions on the HMI.

[0143] Once triggered, the system automatically locks the feed rate control loop (to prevent interference) and executes the following sequence:

[0144] 1. Warning: The central control room issues an audible and visual alarm and the automatic blockage clearing program is activated.

[0145] 2. Rotary pulse jetting: Press The pulse valves are opened in a diagonal jump sequence. This sequence can create a uniform disturbance field in the furnace to the greatest extent and avoid pressure buildup on one side.

[0146] 3. Pulse parameters: Single valve opening time Valve interval .

[0147] 4. Loop: Automatically stops after executing 3 complete loops.

[0148] 5. Evaluation: The system is recalculated. Value. If If successful, a message will be displayed indicating successful clearing and resetting; otherwise, an advanced alert requesting manual intervention will be sent.

[0149] Example 2: Old Dead corner treatment and renovation of fluidized bed furnace

[0150] 1. Background and Limitations of the Modification

[0151] One unit in a smelter Old-fashioned fluidized bed furnace (furnace diameter approximately) Due to its age, the furnace suffers from uneven air distribution around the perimeter, resulting in severe annular dead zones. It requires shutdown and cleaning of dead material every three months, significantly impacting production continuity. Furthermore, the extremely limited space and severely aged refractory concrete in the bellows make it unsuitable for any form of bottom modification.

[0152] 2. Targeted renovation plan

[0153] Due to space constraints on the outer steel platform, only 6 pulse devices were installed along the circumference.

[0154] Considering the small furnace diameter ( If conventional methods are used The horizontal range of the jet after the airflow bounces back may be too long, directly scouring the refractory bricks on the opposite side of the furnace wall.

[0155] Therefore, the spray angle was adjusted to a steeper θ=55°. This large angle design ensures that the high-pressure airflow primarily acts on the radius directly below the spray gun. The fan-shaped area inside (i.e., the dead corner at the root of the furnace wall). After the airflow touches the ground, it mainly generates a vertically upward rebound flow, which strongly agitates the dead material at the root, while the horizontal kinetic energy component is rapidly dissipated, thus protecting the furnace lining on the opposite side.

[0156] By adopting the method of drilling holes without interrupting production or using flange implantation during annual overhaul, mounting bases are directly welded onto the furnace shell steel plate without altering the internal refractory brick structure (using the drilling implantation method), significantly reducing the modification cost and cycle.

[0157] 3. Preventive maintenance mode

[0158] Given the insufficient instrumentation of the old system, which cannot support complex feedback algorithms, and the obvious temporal regularity of dead zone formation in this furnace type (typically starting to accumulate after one week of operation), the control strategy adopts a simple and reliable timed preventive cleaning mode:

[0159] The system automatically performs a standard cleaning procedure every 4 hours.

[0160] Pulse pressure The duration of a single spraying is extended to This is to ensure sufficient loosening capacity for materials that have already begun to settle.

[0161] After the modification, the dead corners at the edge of the furnace remained in a loose fluidized state due to regular strong disturbances, and no more caking occurred.

[0162] Before the modification, due to the dead bed resistance, the average pressure drop of the boiling layer was as high as After the renovation, it remained stable for a long time. The current of the Roots blower decreased by approximately .

[0163] The continuous operation cycle was extended from 3 months before the modification to more than 1 year. During the overhaul, the wear of the wind cap was found to be very uniform, which confirmed the improvement in airflow distribution.

[0164] Example 3: Intelligent Spatial Positioning and Control Strategy Based on Temperature-Pressure Coupling

[0165] This system addresses the characteristics of large fluidized bed furnaces, which exhibit strong overall pressure signal but weak local signal characteristics, by employing a dual detection logic that combines pressure qualitative and temperature localization.

[0166] 1. Hardware Awareness Layer Layout

[0167] High-frequency pressure transmitters were installed in the furnace bottom air chamber and the furnace top flue to monitor the total pressure difference of the entire furnace. .

[0168] Along the circumference of the furnace body, above the distribution plate At the height (i.e., the blind spot or prone area), a suited wear-resistant thermocouple is installed corresponding to the orientation of each pulse spray gun.

[0169] A key monitoring thermocouple is buried directly below the material drop point at the inlet.

[0170] 2. Decision-making level, three-level logical algorithm

[0171] The PLC controller executes the following logic in real time:

[0172] Logic A: Overall fluidization quality warning

[0173] Input total pressure difference Standard deviation (60-second sliding window). Although single-point pressure cannot be located, it can reflect the overall health of the furnace.

[0174] (An excessively flat waveform indicates a tendency for the bed to freeze) or When a system-wide surge occurs, the system enters a standby intervention state.

[0175] Logic B: Dead Zone Spatial Location

[0176] Enter the temperature values ​​for each zone. With the average temperature of the whole furnace The deviation. During normal fluidization, the bed heats up extremely quickly, and the temperature difference at each point is minimal (usually). Once a dead zone or clumping forms in a certain area, material exchange stops and the combustion reaction ceases, causing the temperature in that area to drop.

[0177] It will be significantly lower than the average temperature. (Or it may manifest as abnormally high temperatures in certain oxygen-rich dead zones).

[0178] Calculate the deviation .

[0179] If a certain partition If the temperature is 20 degrees below the average, then that location (e.g., area #3) is identified as a suspected clumping area.

[0180] 3. Execution layer, precise targeting, and comprehensive coverage

[0181] Mode I, Targeted Detonation

[0182] The trigger condition is a logic A alarm and a logic B lock on a specific zone. A high-frequency three-pulse sequence injection (1-second interval) is performed only on the pulse valve corresponding to the temperature anomaly point (e.g., valve #3), reactivating the dead zone using a powerful shock wave. The process stops once the temperature at that point returns to the normal range.

[0183] Mode II, Blind Spot Patrol

[0184] The trigger condition is logic A alarm (deterioration of fluidization), but logic B did not detect a significant temperature difference (indicating that it may be uniform overall caking, or the caking may be located in the temperature measurement blind zone).

[0185] Since precise location is not possible, the system automatically initiates a full furnace inspection.

[0186] according to ... (in diagonal order) spray and blow once in sequence.

[0187] By disturbing the entire bed in all directions, the critical frozen state of the entire bed is broken.

[0188] Mode III, Inlet Special Protection

[0189] The trigger condition is the rate of temperature drop of the TE-Feed (feed inlet thermocouple). .

[0190] Ignore the total pressure and immediately activate the enhanced pulse unit below the feed inlet to prevent wet material accumulation from causing a major disaster.

[0191] Example 4: Telescopic spray gun structure and sealing mechanism

[0192] like Figure 4-6 As shown, this device mainly consists of a furnace wall mounting flange, a ball valve sealing cavity, a guide pipe, a spray gun body, and a propulsion cylinder.

[0193] A Φ50mm silicon nitride (Si3N4) ceramic ball is used as the sealing element. Normally, the spray gun is in the retracted position, with the ceramic ball settling to seal the opening in the furnace wall. An Φ8mm air inlet is opened on the side wall of the guide tube at the rear end of the ball valve, continuously supplying 0.2MPa instrument air. This airflow forms an air curtain at the ball valve seat, blowing away accumulated dust and ensuring that the sealing ball is not stuck when it falls back. The main duct of the spray gun uses a DN50 (Φ57×3.5) seamless steel pipe to reduce friction resistance, but the nozzle tip (R-SiC section) is designed as a converging cone, reducing the outlet diameter to Φ28~30mm.

[0194] This constriction design ensures that the airflow at the outlet reaches the speed of sound (Mach 1) under a gas source pressure of 0.8 MPa and generates a sub-expanded supersonic jet in the furnace. At the same time, it limits the instantaneous gas consumption of a single pulse, prevents the pressure in the gas storage tank from dropping too quickly, and ensures the energy consistency of the three-pulse sequence injection.

[0195] furnace diameter Eight telescopic pulse units are evenly distributed around the circumference of the furnace body.

[0196] Centering arrangement of air cap gaps: On the horizontal projection plane, the axial projection of each pulse spray gun is located on the center line of two adjacent air cap rows (or two adjacent air caps) on the gas distribution plate, that is, the gap area between the air caps directly opposite the spray gun.

[0197] Slicing simulations show that, with a standard wind cap spacing of 100mm, there is a significant high-density dead zone (material volume fraction > 0.55) between the two wind caps. Aiming the spray gun at this gap not only allows direct attack on the core of the dead zone but also avoids the dynamic interference (top-support effect) of the vertical high-speed airflow at the wind cap outlet on the lateral pulse jet, thereby maximizing the radial penetration depth.

[0198] Example 5: Engineering modification parameters of fluidized bed furnace

[0199] 1. Device Configuration

[0200] Equipped with 6 sets of telescopic pulse devices. The propulsion cylinder stroke is 350mm. When the spray gun is fully retracted, the nozzle is 50mm inside the refractory bricks of the furnace wall; when the spray gun is fully extended, the nozzle is inserted diagonally downward into the furnace for 150mm, and the vertical height from the distribution plate is 400mm.

[0201] 3 Gas storage tank, pressure stabilized at 0.8 MPa.

[0202] Calculation boundary conditions: Gas source absolute pressure 0.9 MPa (gauge pressure 0.8 MPa), nozzle converging throat diameter 30 mm. Mass flow rate when sonic choke occurs. The instantaneous standard volumetric flow rate is approximately 2.5 kg / s. Based on a standard air density of 1.29 kg / Nm³, this translates to approximately 1.94 Nm³ / s. For comparison (normal main fan airflow): For a 38 m² zinc concentrate fluidized bed furnace, the normal main fan airflow is approximately 25,000 Nm³ / h (equivalent to 6.94 Nm³ / s). The total make-up air volume for a single 300 ms pulse injection is only 0.58 Nm³; even with a complete three-pulse sequence (cumulative injection of 900 ms), the total make-up air volume is only 1.74 Nm³. The expanded trace amount of gas integrates into the furnace's large buffer space, resulting in minimal impact on the overall load of the exhaust system (less than the main fan's airflow per second).

[0203] Example 6: Closed-loop control strategy based on stretch-pulse coordination

[0204] The control logic executed by this system maximizes the lifespan of the equipment.

[0205] 1. Standby monitoring phase

[0206] The spray gun is fully retracted. The ceramic ball is seated and sealed, and the sealing gas is activated. The PLC is scanning the standard deviation of the air chamber pressure in real time. and the temperature field distribution on the sidewall.

[0207] 2. Abnormal Intervention Stage

[0208] Once the system determines that a certain sector has a risk of dead zone blockage, the PLC initiates the following automation sequence:

[0209] Temporarily increase the sealing air pressure of the spray gun in this sector to 0.4 MPa (cleaning channel).

[0210] Drive the propulsion cylinder to quickly push the spray gun into the furnace (takes about 2 seconds), and the gun head pushes open the ceramic ball.

[0211] Once the spray gun is in position, it executes a three-round burst of pulse logic, each lasting 300ms with a 1s interval. The downward-sloping rebound shockwave is used to break up the agglomerates.

[0212] After the pulse ends, the propulsion cylinder immediately pulls the spray gun back to the guide tube.

[0213] After the spray gun retracts, the ceramic ball automatically falls back to its original position under the action of gravity, and the sealing gas returns to its normal flow rate.

[0214] 3. Safety Interlock

[0215] If a malfunction in the propulsion cylinder causes the spray gun to become stuck in the furnace for more than 5 minutes, the system will trigger an alarm and cut off the gas supply to prevent the spray gun from overheating and being damaged.

[0216] Optimization of jet angle based on a simplified model of a 1m bed (CFD simulation)

[0217] To visually verify the impact of different incident angles on the surface cleaning effect, the inventors constructed a simplified local gas-solid two-phase flow model with an initial particle bed of 1m for comparative verification.

[0218] like Figure 11 As shown, the spray gun is at a 60° angle to the horizontal plane: the flow field cloud diagram shows that the jet has an almost vertical impact on the bottom pressure distribution plate, the radial coverage range is greatly narrowed, the cleaning area of ​​a single gun is small, the suction effect is poor, and it is easy to impact the side wall.

[0219] like Figure 12 As shown, the spray gun is at a 30° angle to the horizontal plane: after the jet develops, it horizontally scours the bottom plate, resulting in a small impact on the plate nodules. It lacks a vertical velocity component and cannot effectively disperse the particles of the distributed plate nodules.

[0220] like Figure 13 As shown, at 45° (the preferred range of this invention): the cloud map clearly shows that after the jet impacts the distribution plate, momentum conversion occurs, forming a wide fan-shaped rebound flow field (Wall Jet Rebound), which has a large vertical scouring area on the bottom plate. It not only effectively entrains the sediment above the distribution plate, but also dissipates kinetic energy reasonably, and the entrainment radiation area is relatively wide.

[0221] Slice simulation verification of spray gun height and orientation

[0222] like Figure 14 As shown, based on the arrangement characteristics of the distribution plate wind caps, a 300×300mm local slice model was used to perform numerical simulation of particle flow in a 1m bed.

[0223] like Figure 15 As shown in the particle concentration distribution curve, a significant inflection point in the material volume fraction occurs at a height of 600 mm from the distribution plate. Limiting the spray gun to below 600 mm ensures that the conserved flow energy is concentrated in the high-density dead zone, avoiding wasted jet energy in the dilute phase region.

[0224] like Figure 16 As shown, the simulation revealed a weak fluidization dead zone with a volume fraction >0.55% existing between the two wind caps. The spray guns were precisely aligned circumferentially with the wind cap gap, achieving accurate targeted strikes to the core of the dead zone.

[0225] This invention provides an intelligent anti-caking system that integrates a telescopic self-sealing mechanism and millisecond-level micro-disturbance control. This invention abandons the erroneous path of airflow purging orifices in existing technologies, and instead adopts the mechanism of shock wave oscillation in the bed.

[0226] To address the issue of spray gun wear, this invention incorporates a dynamic operating mode: normal retraction and sealing, and abnormal extension for operation. Ceramic balls are installed at openings in the furnace wall. When the spray gun retracts, the heat-resistant ceramic balls fall into the conical valve seat under gravity and furnace pressure, physically preventing furnace gas leakage. When the spray gun extends, the nozzle guide surface pushes the ceramic balls into the upper ball cavity, opening the spray channel. A small amount of compressed air is introduced after the sealing ball valve to maintain positive pressure in the valve cavity, preventing backflow of furnace dust and potential jamming of the ball valve.

[0227] Linked with a PLC, it drives the spray gun to quickly pass through the valve body and enter the furnace. The entire mechanism is installed at a 30° angle downwards.

[0228] To address the problem of dense-phase beds hindering airflow penetration, this invention utilizes the rebound effect of a high-pressure jet impacting the dead zone at the furnace bottom to create a strong turbulent field in a localized area. Regardless of the location of the orifice, as long as it is within the sector covered by the rebound flow field, the deposits will be entrained and thrown up.

[0229] The duration of a single injection is strictly controlled within 100-500 ms. It utilizes the shock wave generated by the instantaneous release of gas, rather than the airflow volume, to break up agglomerates. The propagation of the shock wave in the dense phase bed is far less affected by resistance than the airflow itself, allowing it to penetrate the bed barrier and cause high-frequency vibrations in the agglomerates near the distribution plate, thus loosening them. Because the injection time is much shorter than the response time constant of the exhaust fan's frequency conversion adjustment, and the total gas supply is extremely small, this invention does not cause macroscopic fluctuations in the furnace top pressure during the unblocking process, completely eliminating the positive pressure flameout hazard caused by existing technologies (long-duration injection).

[0230] Indirect state inference is achieved using a combination of a sidewall thermocouple array and a high-frequency pressure sensor in the wind chamber / furnace top. A strategy of qualitative pressure assessment (to determine the overall furnace health) and temperature location (to pinpoint the faulty sector) is employed. To accurately determine the installation height and circumferential orientation of the spray gun, the inventors constructed… A local bed slice model (containing 9 wind caps arranged at 100×100mm intervals) was used for CPFD numerical simulation.

[0231] Simulation conditions: air velocity (Normal fluidization), wind cap spacing 100mm.

[0232] Simulated cloud maps show that the particle volume fraction directly above the wind cap is low (approximately 0.3), while a distinct high-density ridge exists in the area between adjacent wind caps, with a volume fraction exceeding 0.55, indicating a weak fluidization dead zone prone to agglomeration. Accordingly, this invention strictly sets the spray gun orientation to align with the wind cap gap. The particle concentration distribution curve along the height direction shows that the material volume fraction at the bottom of the bed gradually decreases with increasing height. At a height of 0.6m from the distribution plate, a clear inflection point appears in the material volume fraction, decreasing from 0.6s at the bottom to 0.35s and then stabilizing (entering the dilute phase transport or fully fluidized zone). The spray gun installation height is limited to below 0.6m (preferably). This ensures that the jet energy is concentrated on the high-density dense phase dead zone; if it is higher than 0.6m, the airflow will mainly pass through the low-density well fluidized zone, and the kinetic energy attenuation when it reaches the bottom plate will be too large; if it is too low (such as less than 0.3m), the sector area covered by a single gun will be significantly reduced, requiring a large increase in the number of equipment, which is not economical.

Claims

1. A spray gun, characterized in that, The device includes a housing (12) containing an internal connecting cavity. One end of the housing (12) is fitted with a sealing flange (15). The main pipe (11) of the spray gun passes through the sealing flange (15) and is inserted into the internal connecting cavity of the housing (12). One branch opening of the housing (12) is connected to an instrument air inlet pipe (14). The housing (12) is provided with a ball-shaped cavity (16). The ball-shaped cavity (16) is located downstream of the air inlet of the instrument air inlet pipe (14). The ball-shaped cavity (16) contains a ceramic ball (13). The diameter of the ceramic ball (13) is larger than the diameter of the internal connecting cavity.

2. The spray gun according to claim 1, characterized in that, The outlet end (17) of the main pipe (11) of the spray gun is frustum-shaped. The diameter of the outlet end (17) is smaller than the diameter of other parts. The diameter of the outlet end (17) of the main pipe (11) of the spray gun is Φ28~30mm.

3. The spray gun according to claim 1, characterized in that, An electromagnetic pulse valve (5) is installed at one end of the housing (12).

4. A fluidized bed roasting furnace, comprising a mounting base (2) installed in the fluidized bed roasting furnace, characterized in that, The mounting base (2) is equipped with a spray gun (1) according to any one of claims 1-3, the spray gun (1) is a pulse spray gun, and the spray gun (1) is set obliquely downward at an angle θ to the horizontal plane, 30°≤θ≤60°.

5. In the fluidized bed roasting furnace according to claim 4, the height h of the outlet of the spray gun (1) from the upper surface of the gas distribution plate is 300mm~600mm; preferably 300mm~500mm.

6. The fluidized bed roasting furnace according to claim 4, characterized in that, The mounting base (2) is provided with a constant air inlet (4), which is connected to the air inlet of the instrument air inlet pipe (14).

7. A method for preventing agglomeration in a fluidized bed roasting furnace, characterized in that... Includes the following steps: When the pressure warning of the fluidized bed roasting furnace is triggered and the temperature anomaly point is successfully located, the spray gun sprays a high-pressure pulse airflow toward the bottom of the fluidized bed roasting furnace. The high-pressure pulse airflow is inclined downward at an angle θ with the horizontal plane, with 30°≤θ≤60°. This causes the airflow that rebounds after passing the bottom of the fluidized bed roasting furnace to activate the temperature anomaly point until the temperature of the temperature anomaly point rises back. When the pressure warning of the fluidized bed roasting furnace is issued and the temperature distribution is uniform, start the whole furnace to rotate and blow in the diagonal sequence of the fluidized bed roasting furnace to break the critical state through all-round disturbance.

8. The method for preventing agglomeration in a fluidized bed roasting furnace according to claim 7, characterized in that: The pressure of the high-pressure pulsed airflow is 0.6~0.8MPa, the single injection time is 100ms~500ms, and the injection interval is 1~2s.

9. The method for preventing agglomeration in a fluidized bed roasting furnace according to claim 7, characterized in that: The pressure warning method is to use high-frequency pressure sensors installed in the wind chamber and furnace top to calculate the high-order statistics of the pressure difference signal of the entire furnace bed in real time, which is used to determine whether the fluidization state of the entire furnace has deteriorated. When the fluidization state of the entire furnace deteriorates, it is a pressure warning. Preferably, the higher-order statistics of the total furnace bed pressure difference signal are the standard deviations of the total furnace bed pressure difference signal, specifically: Standard deviation criterion: Calculate the standard deviation σ of ΔP using a preset time sliding window; When σ < 150 Pa, the bed is judged to have a tendency to freeze or become dead. When σ>400Pa, it is determined that an overall slug in the bed has occurred.

10. The method for preventing agglomeration in a fluidized bed roasting furnace according to claim 7, characterized in that: Real-time calculation of temperature T in each zone i With the average temperature of the entire furnace T avg Deviation value D evi When a certain partition deviation D evi When the temperature is below -20℃, the zone is identified as a temperature anomaly.

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