Accurate continuous gasification system and method for circuit board resin based on reaction kinetics regulation and control

Abstract

The invention relates to the technical field of waste circuit board recovery, and particularly discloses a circuit board resin precise continuous gasification system and method based on reaction kinetics regulation and control. The method comprises the following steps: acquiring three-dimensional temperature field distribution in a gasification furnace, and detecting the component concentration of the resin gasification product through a multi-component flue gas analyzer; the circumference of the gasification furnace is divided into a plurality of fan-shaped microwave radiation areas, and the microwave power density of each area is dynamically adjusted in a time sequence rotation mode; a pulse type microwave heating strategy is established, heating pulse parameters are accurately regulated and controlled according to the concentration change rate of gasified products, and efficient gasification of the deep layer and the surface layer of the resin is achieved in combination with dual-frequency microwave synergistic heating; a convection exhaust mechanism is constructed, the flow rate and temperature of the introduced gas are controlled, and gasification product gas is sucked through negative pressure. Accurate and continuous regulation and control of the resin gasification process are achieved, and accurate gasification of the resin in the circuit board is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of waste circuit board recycling, and specifically discloses a precise and continuous gasification system and method for circuit board resin based on reaction kinetics regulation. Background Art

[0002] Waste circuit boards are typically treated through high-temperature processes such as pyrolysis and gasification to recover combustible gases and enrich metal components. This is one of the mainstream approaches to electronic waste resource recovery. Existing processes commonly face the following challenges in practice: Circuit board resins often exhibit significant spatial heterogeneity during the heating phase. A sudden temperature increase in a local area leads to rapid carbonization, while adjacent areas remain under-gasified. This uneven heating and cooling directly causes significant fluctuations in the composition of the gas products, complicating subsequent condensation, purification, and separation processes. When heat-treating thick or multi-layer circuit boards, uneven heating of the board makes complete gasification difficult, resulting in a significant proportion of residues. This, in turn, reduces the overall organic matter recovery rate and impacts resource utilization efficiency.

[0003] Currently, there is still a lack of technical solutions that can simultaneously eliminate the above-mentioned non-uniformity phenomenon under continuous working conditions and fully vaporize the circuit board resin.

[0004] In view of this, the present application proposes a precise and continuous gasification system and method for circuit board resin based on reaction kinetics regulation. Summary of the Invention

[0005] To achieve the above objectives, this application provides a system and method for precise and continuous gasification of circuit board resin based on reaction kinetics control. The specific technical solutions are as follows:

[0006] The precise and continuous gasification method for circuit board resin based on reaction kinetics control includes:

[0007] A multi-point temperature sensor array is evenly deployed on the inner wall of the gasifier to obtain the three-dimensional temperature field distribution inside the gasifier. A multi-component flue gas analyzer is installed at the exhaust port of the gasifier to detect the concentration of various types of resin gasification products.

[0008] The circumference of the gasifier is divided into multiple sector-shaped microwave radiation zones, which emit microwaves in a time-sequential rotation manner. The microwave power density of each sector-shaped microwave radiation zone is dynamically adjusted according to the three-dimensional temperature field distribution.

[0009] A pulsed microwave heating strategy was established to adjust the microwave heating pulse parameters based on the detected concentration change rate of the resin vaporization product components.

[0010] Adopting dual-frequency microwave synergistic heating mechanism, low-frequency microwaves heat the circuit board resin deeply, and high-frequency microwaves heat the surface of the circuit board resin;

[0011] Construct a convection exhaust mechanism for the gasifier, introduce gas from one end of the gasifier, control the gas flow rate and preheat the gas, and extract the gasified resin gas with negative pressure at the other end.

[0012] Preferably, a multi-point temperature sensor array is evenly deployed on the inner wall of the gasifier in a horizontal layered layout to form a three-dimensional temperature measurement grid; the collected temperature data is used to construct a continuous temperature field distribution function through a three-dimensional interpolation algorithm to obtain a three-dimensional temperature field distribution;

[0013] An infrared spectroscopy flue gas analyzer is installed at the exhaust port of the gasifier. The infrared spectroscopy flue gas analyzer continuously monitors the concentration of each component of the resin gasification product at a fixed sampling frequency. By establishing the first-order derivative and second-order derivative of the time series of the concentration of the resin gasification product components, the rate change and acceleration characteristics of the resin gasification reaction are evaluated in real time.

[0014] Preferably, the circumference of the gasifier is evenly divided into a plurality of sector-shaped microwave radiation zones along the radial direction, and each sector-shaped microwave radiation zone is equipped with an independent microwave energy feeding device at a corresponding position on the outer wall of the gasifier to heat the circuit board in the gasifier;

[0015] The magnetrons of each sector-shaped microwave radiation zone are adjusted by an independent power control unit, the sector-shaped microwave radiation zones are numbered, and the microwave transmission power of each sector-shaped microwave radiation zone is adjusted according to the number;

[0016] A time-rotating microwave transmission mechanism is constructed for simultaneous operation of multiple sectors. Multiple non-adjacent sector-shaped microwave radiation areas are selected to transmit microwaves simultaneously in each working cycle. When multiple sectors in the current cycle complete the microwave transmission work, the adjacent multiple sectors take over the microwave transmission work.

[0017] Preferably, a microwave power density regulation algorithm based on the radial-axial temperature field feedback of the gasifier is established; the temperature field data of the gasifier is mapped to each sector-shaped microwave radiation zone; the average temperature distribution of the sector at different height layers is calculated, and the volume average temperature of the sector is calculated, the target temperature and temperature deviation are defined, and the microwave power density is regulated using an adaptive proportional-integral-differential control law.

[0018] Preferably, the power allocation strategy is dynamically optimized according to the first-order derivative and the second-order derivative of the flue gas component concentration; based on the obtained resin gasification product component concentration, the first-order derivative of the resin gasification product component concentration is calculated to characterize the gasification reaction rate; and the second-order derivative is calculated to characterize the reaction acceleration;

[0019] Construct comprehensive gasification dynamic indicators and adjust microwave power according to the comprehensive gasification dynamic indicators.

[0020] Preferably, a pulsed microwave heating strategy is established, replacing the continuous microwave heating mode with an intermittent pulse heating mode;

[0021] The pulse parameters of the microwave pulse sequence in a single sector are defined, including pulse width, pulse interval, pulse power peak and pulse duty cycle; pulsed microwave heating is carried out by alternating periodic energy input and heat diffusion processes; the pulse parameters of pulsed microwave heating are adjusted based on the concentration change rate of the resin gasification product components.

[0022] Preferably, a heat accumulation protection algorithm is established to monitor the heat accumulation effect during the resin gasification process, define a local heat accumulation index, and insert a cooling interval when the local heat accumulation index exceeds a critical value to extend the pulse interval of the sector;

[0023] A phase coordination control mechanism for microwave pulse sequences is established to avoid electromagnetic interference and power fluctuations caused by multiple sector pulses reaching peak values ​​at the same time by phase staggering.

[0024] Preferably, a dual-frequency microwave collaborative heating mechanism is constructed, and a dual-frequency magnetron combination is configured in each sector-shaped microwave radiation zone, including a low-frequency magnetron and a high-frequency magnetron, so that the resin of the circuit board is uniformly heated according to the low-frequency microwave and the high-frequency microwave;

[0025] Time division multiplexing technology is used for coordinated control to avoid mutual interference between the two frequencies of microwaves.

[0026] Preferably, a preheated carrier gas is delivered to the gas inlet end of the gasifier, and a spiral tube electric heater is used to preheat the carrier gas; a negative pressure suction device is provided at the exhaust end of the gasifier, and the exhaust end pipeline adopts an insulation design to maintain the pipeline temperature within a predetermined range;

[0027] A convection circulation control mechanism is established inside the gasifier. By adjusting the matching relationship between the carrier gas inlet flow rate and the exhaust negative pressure, an axial convection field is formed inside the furnace. At the same time, the carrier gas passage time in the furnace is controlled by adjusting the air flow rate inside the furnace.

[0028] A precise and continuous vaporization system for circuit board resin based on reaction kinetics control, which is used to implement the precise and continuous vaporization method for circuit board resin based on reaction kinetics control, includes: a data acquisition module, a multi-sector microwave emission module, a pulsed microwave heating module, a dual-frequency microwave heating module, and a resin vaporization circulation module;

[0029] The data acquisition module evenly deploys a multi-point temperature sensor array on the inner wall of the gasifier to obtain the three-dimensional temperature field distribution in the gasifier, and installs a multi-component flue gas analyzer at the exhaust port of the gasifier to detect the concentration of multiple types of resin gasification product components;

[0030] The multi-sector microwave emission module divides the circumference of the gasifier into multiple sector-shaped microwave radiation zones. The sector-shaped microwave radiation zones emit microwaves in a time-sequential rotation manner, and dynamically adjust the microwave power density of each sector-shaped microwave radiation zone according to the three-dimensional temperature field distribution;

[0031] The pulse microwave heating module establishes a pulse microwave heating strategy and adjusts the microwave heating pulse parameters according to the detected concentration change rate of the resin gasification product component;

[0032] The dual-frequency microwave heating module adopts a dual-frequency microwave synergistic heating mechanism, where low-frequency microwaves heat the circuit board resin in depth, and high-frequency microwaves heat the circuit board resin on the surface.

[0033] The resin gasification circulation module is used to construct a convection exhaust mechanism of the gasifier, introduce gas from one end of the gasifier, control the flow rate of the introduced gas and preheat the introduced gas, and suck the gasified resin gas with negative pressure at the other end.

[0034] The beneficial effects of the present application are as follows: the present application realizes real-time monitoring of the three-dimensional temperature field in the gasification furnace by evenly arranging a multi-point temperature sensor array on the inner wall of the gasification furnace, and combines the multi-component flue gas analyzer at the exhaust port to effectively detect the multi-type concentrations of resin gasification products, thereby improving the controllability and safety of the gasification process.

[0035] This application divides the circumference of the gasifier into multiple sector-shaped microwave radiation zones and uses time-sequential rotation to emit microwaves, which can avoid hot spots caused by local continuous heating. It dynamically adjusts the power density of each zone based on temperature field information, effectively improves heating uniformity, and prevents local overheating and insufficient gasification.

[0036] This application establishes a pulsed microwave heating strategy, which can flexibly adjust the microwave heating parameters according to the concentration change rate of the resin gasification product components, achieve a dynamic balance between intermittent energy input and heat diffusion, effectively reduce the risk of heat accumulation, and enhance the ability to fine-tune the gasification reaction.

[0037] This application adopts a dual-frequency microwave collaborative heating mechanism, using low-frequency microwaves to achieve deep heating of the resin and high-frequency microwaves to enhance the heating of the surface layer, ensuring that both the inner and outer layers of resin can be fully vaporized, significantly improving the overall vaporization efficiency of the thick circuit board.

[0038] This application constructs a convection exhaust mechanism, which adopts a combination of preheated carrier gas and negative pressure suction to form a stable airflow channel, improve the efficiency of timely discharge of gasification products, and reduce the risk of gasification residues and secondary pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 Flow chart of the precise continuous gasification method for circuit board resin based on reaction kinetics control provided in this application;

[0040] Figure 2 Flowchart of multi-sector microwave zoning and dynamic control provided for this application;

[0041] Figure 3 Flow chart of pulsed microwave heating and heat accumulation protection provided for this application;

[0042] Figure 4 The dual-frequency microwave collaborative heating control flow chart provided in this application;

[0043] Figure 5 This is a structural diagram of the circuit board resin precise continuous gasification system based on reaction kinetics control provided in this application. DETAILED DESCRIPTION

[0044] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the drawings in the specification.

[0045] In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can also be implemented in other ways different from those described herein. Those skilled in the art can make similar generalizations without violating the connotation of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0046] Secondly, the term "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present application. The phrase "in one embodiment" appearing in various places throughout this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0047] Example 1

[0048] Reference Figure 1 , which is the first embodiment of the present application, provides a precise and continuous gasification method for circuit board resin based on reaction kinetics regulation.

[0049] Step 1: Evenly deploy a multi-point temperature sensor array on the inner wall of the gasifier to obtain the three-dimensional temperature field distribution inside the gasifier. Install a multi-component flue gas analyzer at the exhaust port of the gasifier to detect the concentration of multiple types of resin gasification products.

[0050] The optical fiber temperature sensor array is evenly deployed on the inner wall of the gasifier in a horizontal layered layout. For example, the sensor sets 8 horizontal temperature measurement layers along the axial direction of the furnace body. Each temperature measurement layer has 12 measurement points evenly distributed along the circumferential direction in the same horizontal plane. The two adjacent horizontal temperature measurement layers are arranged at equal intervals to form a regular three-dimensional temperature measurement grid. The optical fiber temperature sensor is made of high-temperature resistant quartz optical fiber and is led out to the external optical fiber demodulator through a sealed conduit reserved in the furnace wall. The spatial coordinates of each temperature sensor measurement point are calculated through the cylindrical coordinate system. Precise positioning, where Indicates the Circumferential angle position, Indicates the Axial height position. Specifically, Indicates the temperature sensing point at the 7th angle and the 2nd altitude layer.

[0051] The temperature data collected by the temperature sensor array is used to construct a continuous temperature field distribution function through a three-dimensional interpolation algorithm ,in, represents the time variable, r is the circumferential angle variable, and z is the axial height variable. The interpolation algorithm uses the radial basis function method to convert the temperature values ​​of discrete measuring points into Mapped to a continuous spatial temperature distribution: ;in, for The weight coefficient of the measuring point is determined mainly by the spatial distance between the interpolation point and the measuring point of each temperature sensor. Generally, the closer the interpolation point is to the measuring point, the greater the weight is assigned, and the farther the point is, the smaller the weight is. The weight coefficient automatically calculates the weight of each measuring point based on the actual spatial distribution; is the radial basis function, Represents the spatial distance norm.

[0052] Using optical fiber temperature sensors to collect temperature data inside the gasifier can not only dynamically track the temperature inside the gasifier, but also avoid measurement errors caused by the heating of temperature sensors such as thermocouples or platinum resistance sensors during microwave heating. Through a horizontally layered high-density temperature measurement network, the temperature distribution characteristics of each height layer during the resin gasification process can be accurately captured, and the temperature gradient changes in the gasifier can be clearly reflected, providing reliable temperature field data support for the zoning control of the microwave power of the gasifier.

[0053] An infrared spectroscopy flue gas analyzer is installed at the gasifier exhaust port. The analyzer features a built-in standard spectral library and can simultaneously detect a variety of products produced by the vaporization of epoxy, phenolic, and polyimide resins, including organic gas components such as phenols, aldehydes, ketones, and small hydrocarbons. A particulate filter is installed at the front end of the infrared spectroscopy flue gas analyzer's probe to prevent solid resin particles from entering the analyzer. The infrared spectroscopy flue gas analyzer's flue gas sampling line utilizes a heat-insulating design to maintain the line temperature above the flue gas dew point by at least 50°C, preventing condensable components from liquefying in the line and causing measurement deviations.

[0054] The flue gas analyzer continuously monitors the concentration of each component of the resin gasification product at a fixed sampling frequency ,in, Indicates the Gas components, The first Components By establishing the first derivative of the resin gasification product concentration time series and the second-order derivative , assessing the rate changes and acceleration characteristics of the resin vaporization reaction in real time. A sharp increase in the concentration of a characteristic product indicates that the corresponding type of resin is rapidly vaporizing, allowing the prevailing vaporization reaction type to be determined. For example, when the phenol concentration increases from 100 ppm to 800 ppm within 5 seconds, the concentration change rate reaches 140 ppm / s, indicating that the epoxy resin is undergoing a period of intense decomposition and vaporization.

[0055] The multi-dimensional monitoring system constructed in this step can fully grasp the reaction state of the resin gasification process in the gasifier, realize accurate perception and quantitative characterization of the resin gasification process, and provide a complete state information basis for subsequent reaction kinetics control.

[0056] Step 2: Divide the circumference of the gasifier into multiple sector-shaped microwave radiation zones. The sector-shaped microwave radiation zones emit microwaves in a time-sequential rotation manner. According to the temperature field, the microwave power density of each sector-shaped microwave radiation zone is dynamically adjusted. The sector-shaped microwave radiation zone can be referred to as a sector, and multiple sector-shaped microwave radiation zones can be referred to as multiple sectors. Figure 2 , which is the multi-sector microwave partitioning and dynamic control flow chart of this step.

[0057] The circumference of the gasifier is evenly divided into N sector-shaped microwave radiation zones along the radial direction. The central angle of each sector-shaped microwave radiation zone is , generally, set N to an even number and satisfy , to ensure the spatial resolution of microwave radiation and the flexibility of multiple sectors working simultaneously. Each sector-shaped microwave radiation zone is equipped with an independent microwave feeding device at the corresponding position on the outer wall of the gasifier, including a magnetron, a waveguide tube and a microwave feed port. For example, the magnetron adopts an industrial-grade continuous wave magnetron, the operating frequency is selected to be 2.45GHz, and the rated power range of a single tube is 1-3kW. The microwave energy is introduced into the interior of the gasifier through a rectangular waveguide; a quartz glass sealing window is provided at the connection between the waveguide tube and the furnace wall to ensure both microwave transmission and maintain the sealing of the furnace.

[0058] The magnetrons of each sector microwave radiation zone are regulated by an independent power control unit, which uses a thyristor voltage regulator to achieve 0-100% continuous power regulation. The sector microwave radiation zones are numbered, and the angle range of the i-th sector microwave radiation zone is ,in, , The instantaneous microwave power density of each sector microwave radiation zone is expressed as Through precise sector-shaped partitioning design, differentiated heating of resin materials at different positions in the gasifier can be achieved, avoiding the uneven temperature field problem caused by traditional overall heating methods.

[0059] Construct a time-sequential microwave transmission mechanism for simultaneous operation of multiple sectors, and select m non-adjacent sector-shaped microwave radiation areas to transmit microwaves simultaneously at each working moment. For example, set , that is, one-third of the non-adjacent sectors are heated by microwaves at the same time, is the number of non-adjacent sectors that perform microwave heating at the same time, ensuring that there is at least one sector between any two sectors that work simultaneously. Define the sector activation matrix , where j represents the timing step, i and k represent the sector numbers, i∈{1,2,..., }, k∈{1,2,..., }, Indicates that the i-th sector is active in the j-th timing step, Indicates that it is in the closed state. Construct activation constraints: For any time sequence step j, if and , then it must satisfy (Consider loop boundary conditions).

[0060] Using the spiral rotation strategy, the set of activated sectors in the jth timing step is ,in, represents the first sector in the set of activated sectors at the jth timing step sectors, the kth sector in the set of activated sectors in the jth timing step is The spiral activation mode enables each sector to obtain equal activation time within a complete rotation cycle while maintaining the spatial dispersion of the activated sectors. The basic time slice length is defined as , complete rotation cycle , each sector is activated exactly once during this cycle.

[0061] For example, for N=12 sector microwave radiation zones, the first sequential step activates sectors {1, 4, 7, 10}, the second sequential step activates sectors {2, 5, 8, 11}, and the third sequential step activates sectors {3, 6, 9, 12}. This multi-sector simultaneous operation mode improves the heating efficiency to that of a single sector operation mode. times, significantly shortening the time required for resin vaporization, and also avoiding the problem of electromagnetic interference when all sectors are heated by microwaves at the same time and the thermal stress problem on the circuit board.

[0062] Establish a microwave power density regulation algorithm based on the radial-axial temperature field feedback of the gasifier; map the temperature field data of the gasifier to each sector microwave radiation zone; calculate the average temperature distribution of the i-th sector microwave radiation zone at different altitude layers ,in, Represents the radial integral domain of the i-th sector microwave radiation zone; further calculate the volume average temperature of the sector , where H is the effective height of the gasifier; define the target temperature and temperature deviation .

[0063] Microwave power density regulation adopts adaptive proportional-integral-differential control law:

[0064]

[0065] in, is the basic power density, is the proportionality coefficient, is the integration coefficient, is the differential coefficient. Control parameters are dynamically adjusted based on the temperature response characteristics: when the temperature change rate is large, the differential action is increased to suppress overshoot, and when there is a steady-state deviation, the integral action is enhanced to eliminate static error. This adaptive control strategy enables rapid response to temperature changes while maintaining heating stability.

[0066] Dynamically optimize the power allocation strategy based on the first-order derivative and second-order derivative of the flue gas component concentration. Gas component concentration , calculate its first-order derivative Characterizes gasification reaction rate, second-order derivative Characterize reaction acceleration. Construct comprehensive gasification dynamic index :

[0067]

[0068] in, For the The weight coefficient of each gas, is the acceleration impact factor, and M is the total number of monitored gas types. and When , it indicates that the gasification reaction is accelerating; when but , indicating that the reaction rate is still increasing but has begun to slow down.

[0069] Establish a power regulation strategy based on the dynamic characteristics of the reaction. When the second-order derivative of key products (such as phenols) is detected, hour, is the concentration of the key product, The acceleration threshold indicates that the reaction is too intense, and the power density of all active sectors is immediately reduced to ,in, is the reduced active sector power density, is the attenuation coefficient. When the first-order derivative In target range When the second-order derivative is close to zero, and are the lower and upper limits of the reaction rate, respectively, indicating that the reaction is in a stable state and maintains the current power unchanged. When , judge according to the sign of the second-order derivative: if , indicating that the reaction continues to slow down and the power density needs to be increased ,in, is the increase in power density.

[0070] The partitioned controllable microwave heating mechanism with multiple sectors working simultaneously established in this step improves the heating efficiency of the resin in the circuit board; the spiral propulsion rotation strategy ensures that all sectors have equal heating opportunities, and the simultaneous operation of multiple non-adjacent sectors avoids local thermal stress concentration. The intelligent power regulation based on the radial-axial temperature field maintains the temperature uniformity of the entire vaporization space. The thermal stress protection mechanism ensures the safety and stability of the equipment operation, and ultimately achieves efficient, uniform, and controllable vaporization of the circuit board resin, greatly improving the resin vaporization quality and processing efficiency.

[0071] Step 3: Establish a pulsed microwave heating strategy and adjust the microwave heating pulse parameters based on the detected concentration change rate of the resin vaporization product. Figure 3 , which is the flow chart of pulsed microwave heating and heat accumulation protection in this step.

[0072] Establish a pulsed microwave heating strategy to replace the continuous microwave heating mode with an intermittent pulse heating mode. Define the pulse parameters of the microwave pulse sequence for a single sector, including the pulse width. , pulse interval , pulse power peak and pulse duty cycle Pulse heating alternates between periodic energy input and heat diffusion, avoiding the problem of resin carbonization caused by local hot spots formed by excessive heat accumulation on the resin surface during continuous microwave heating.

[0073] Based on the concentration change rate of the resin gasification product, the pulse parameters of the pulse microwave heating are adjusted; according to the first Characteristic gasification product concentration , according to the calculated gasification reaction rate and reaction acceleration . Define the comprehensive gasification rate index ,in, For the The weight coefficient of the product, is the total number of gas types monitored; when Exceeding the set reaction rate upper limit When the pulse width is too high, it indicates that the resin gasification reaction is too intense and there is a risk of local overheating. ,in, is the adjusted pulse width, To achieve the target gasification rate, the average power input is reduced by shortening the pulse width to suppress the excessively fast gasification reaction.

[0074] Establish a heat accumulation protection algorithm to monitor the heat accumulation effect during the resin gasification process. Define local heat accumulation indicators ,in For the sectors in The instantaneous power density at time , For the evaluation time window, is the thermal diffusion time constant of the resin material. Exceeding the critical value When the cooling interval is forced to be inserted, the pulse interval of the sector is extended to ,in, is the extended pulse interval, is the interval adjustment coefficient; critical value The setting method must be based on the thermal diffusion characteristics of the resin material and the safety requirements of the gasification process, combined with the calculation formula for the local heat accumulation index and determined through experimental data. By selecting different types of resin materials, their local heat accumulation effects are monitored under simulated actual heating conditions, and the critical point that leads to carbonization or performance degradation is recorded and set as the critical value. In addition, the critical value can be specifically adjusted based on the thermal stability characteristics of different resins to ensure adaptability and reliability. Dynamic adjustment of the intermittent period based on the heat accumulation history can effectively prevent carbonization caused by excessive heat accumulation within the resin.

[0075] According to the gasification characteristics of different types of resins, a pulse power peak optimization strategy is established by analyzing the characteristic product spectra of epoxy resin, phenolic resin, and polyimide resin. For example, for epoxy resin with poor thermal stability, when the concentration of bisphenol A decomposition products increases sharply, the pulse power peak is reduced. ,in, is the power correction factor for epoxy resin. For polyimide resins with higher thermal stability, the peak power is appropriately increased to ensure sufficient vaporization. For example, when the phenol concentration change rate reaches 150 ppm / s, the peak pulse power is reduced from 2.5 kW to 1.8 kW, while the pulse width is shortened from 200 ms to 140 ms.

[0076] Establish a phase coordination control mechanism for the pulse sequence to ensure electromagnetic compatibility when multiple sectors work simultaneously. Define the pulse phase difference between adjacent working sectors. , Indicates the sectors, Indicates the sectors adjacent to each other, where is the number of simultaneously active sectors. Phase staggering avoids electromagnetic interference and power fluctuations caused by simultaneous peak pulses from multiple sectors. A pulse synchronization triggering system is established, with the pulse sequences of all sectors controlled by a unified clock signal to ensure phase stability. For example, for four simultaneously active sectors, the phase differences are set to 0°, 90°, 180°, and 270°, respectively, to achieve a uniformly distributed power output pattern.

[0077] The pulsed microwave heating strategy established in this step effectively prevents the formation of hot spots inside the resin through intermittent energy input. Real-time feedback adjustment based on the rate of change of the vaporization product concentration ensures the smooth and controllable vaporization process. The heat accumulation protection algorithm completely eliminates the risk of local carbonization. Multi-frequency pulse superposition and phase coordination control further improve the uniformity of heating, which can achieve precise temperature control and vaporization of the circuit board resin, and significantly improve the quality of the circuit board product recovery after resin vaporization.

[0078] Step 4: Use dual-frequency microwave synergistic heating mechanism, low-frequency microwaves heat the circuit board resin deeply, and high-frequency microwaves heat the circuit board resin surface. Figure 4 , which is the dual-frequency microwave collaborative heating control flow chart of this step.

[0079] A dual-frequency microwave collaborative heating mechanism is constructed, and a dual-frequency magnetron combination is configured in each fan-shaped microwave radiation zone, including a low-frequency magnetron and a high-frequency magnetron. For example, the low-frequency microwave selects the 915MHz frequency band, and the high-frequency microwave selects the 2450MHz frequency band. The low-frequency microwave and the high-frequency microwave are coupled through a power combiner and input into the gasification furnace through the same waveguide system. The longer wavelength of the low-frequency microwave allows the microwave penetration depth to reach more than 80% of the thickness of the circuit board resin layer, achieving volume heating inside the resin. The formula for calculating the penetration depth of microwaves in the resin medium is: ,in, represents the microwave penetration depth, is the speed of light in vacuum, is the microwave frequency, is the dielectric loss factor of the resin material. This formula accurately calculates the penetration depth of microwaves of different frequencies into a specific resin material, thereby optimizing frequency selection. The low-frequency microwave generator utilizes a continuous-wave magnetron, equipped with a water-cooling system to maintain a stable operating temperature. The output power is continuously adjustable from 500W to 3000W, with power stability better than ±2%.

[0080] High-frequency microwaves have a relatively shallow penetration depth, primarily affecting the resin's surface within 1-2 mm. The rapid heating of the surface creates a temperature gradient that promotes heat conduction from the interior, complementing the deeper heating provided by low-frequency microwaves. High-frequency microwave generators also utilize industrial-grade magnetrons equipped with pulse modulation circuitry. The two microwave frequencies are coupled via a power combiner to ensure mutual interference between the two microwave signals.

[0081] The power distribution of low frequency and high frequency follows the principle of dynamic adjustment, and the power ratio is determined according to the monitored resin thickness distribution. The power distribution coefficient is defined as ,in, is the low frequency microwave power, is the high frequency microwave power. In the initial stage of gasification, The value is set in the range of 0.7-0.8 to ensure that the resin is fully preheated; as the gasification proceeds, gradually reduce The value is increased to 0.4-0.5, and surface heating is strengthened to maintain a stable vaporization rate.

[0082] In order to avoid mutual interference between the two frequencies of microwaves, time division multiplexing technology is used for coordinated control. The duty cycle of low frequency microwave is , the high frequency microwave duty cycle is ,satisfy , leaving 5% of the time for microwave switching and stabilization. When set to 100ms, the first 70ms are for low-frequency microwaves, the next 25ms for high-frequency microwaves, and the 5ms in between serve as a switching buffer. This alternating heating method ensures continuous heating while avoiding standing waves caused by frequency aliasing.

[0083] This step significantly reduces the temperature gradient within the resin through the synergistic effect of low-frequency deep heating and high-frequency surface heating, keeping the temperature difference within 20°C. This effectively avoids the problem of surface overheating and carbonization while maintaining insufficient internal temperature. This dual-frequency synergistic heating improves microwave energy utilization efficiency and enhances heating stability. The precise vaporization heating control and efficient energy utilization of this step ensure uniform and complete vaporization of the resin.

[0084] Step 5: Construct a convection exhaust mechanism for the gasifier, introduce gas from one end of the gasifier, control the gas flow rate and preheat the gas, and set a negative pressure to suck the vaporized resin gas at the other end.

[0085] Preheated carrier gas is delivered to the gasifier's inlet using a spiral electric heater. Typically, the preheat temperature is between 290°C and 310°C. A mass flow controller precisely adjusts the carrier gas flow rate to ensure sufficient enthalpy upon entering the gasifier to maintain the ideal temperature for the resin vaporization reaction. This precisely controlled inlet gas effectively prevents condensation of the resin vaporization products caused by carrier gas temperature fluctuations.

[0086] A negative pressure suction device is installed at the gasifier's exhaust port, using a centrifugal fan to provide a stable negative pressure, which is regulated through variable frequency speed control. The exhaust piping is insulated, maintaining a temperature between 240-260°C to prevent condensation and blockage of the vaporized resin during transport. The negative pressure provided by the centrifugal fan draws the vaporized resin out of the reaction zone, ensuring its timely removal.

[0087] A convection circulation control mechanism has been established within the gasifier. By adjusting the matching relationship between the carrier gas inlet flow rate and the exhaust negative pressure, a stable axial convection field is formed within the furnace. By adjusting the airflow velocity within the furnace, the carrier gas's transit time within the furnace is controlled. Controlling the carrier gas's transit time ensures sufficient vaporization of the resin while preventing excessive retention of the resin vaporization products, which can lead to secondary pyrolysis. The convection circulation within the gasifier also homogenizes the furnace's temperature field. This convection circulation quickly removes excess heat from local hotspots and transfers it to relatively cooler areas, achieving dynamic equilibrium within the furnace's temperature field.

[0088] The convection exhaust mechanism constructed in this step effectively solves the problem of hot spot concentration during microwave heating through the forced convection of the carrier gas, quickly diffuses the heat from the local overheating area to the entire reaction space, prevents the resin from carbonizing due to local overheating, and at the same time ensures that the vaporization products of the inner layer of the circuit board resin are sucked out, thereby improving the overall vaporization efficiency of the resin in the circuit board.

[0089] Example 2

[0090] Reference Figure 5 , which is the second embodiment of the present application, provides a precise continuous gasification system for circuit board resin based on reaction kinetics regulation.

[0091] The system includes a data acquisition module, a multi-sector microwave emission module, a pulsed microwave heating module, a dual-frequency microwave heating module and a resin gasification circulation module.

[0092] The data acquisition module evenly deploys a multi-point temperature sensor array on the inner wall of the gasifier to obtain the three-dimensional temperature field distribution in the gasifier, and installs a multi-component flue gas analyzer at the exhaust port of the gasifier to detect the concentration of multiple types of resin gasification products.

[0093] The multi-sector microwave emission module divides the circumference of the gasifier into multiple sector-shaped microwave radiation zones. The sector-shaped microwave radiation zones emit microwaves in a time-sequential rotation manner, and dynamically adjust the microwave power density of each sector-shaped microwave radiation zone according to the temperature field.

[0094] The pulse microwave heating module establishes a pulse microwave heating strategy and adjusts microwave heating pulse parameters based on the detected concentration change rate of the resin gasification product.

[0095] The dual-frequency microwave heating module adopts a dual-frequency microwave cooperative heating mechanism, wherein low-frequency microwaves perform deep heating on the circuit board resin, and high-frequency microwaves perform surface heating on the circuit board resin.

[0096] The resin gasification circulation module is used to construct a convection exhaust mechanism of the gasifier, introduce gas from one end of the gasifier, control the flow rate of the introduced gas and preheat the introduced gas, and set a negative pressure at the other end to suck the gasified resin gas.

[0097] In the embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. The device embodiments described above are merely schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some communication interface, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0098] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of this application, ordinary technicians in this field can also change, modify, replace and modify the above-mentioned embodiments without departing from the purpose of this application and the scope of protection of the claims, which are all within the protection of this application.

Claims

1. A precise and continuous gasification method for circuit board resin based on reaction kinetics control, characterized in that: include: A multi-point temperature sensor array is evenly deployed on the inner wall of the gasifier to obtain the three-dimensional temperature field distribution inside the gasifier. A multi-component flue gas analyzer is installed at the exhaust port of the gasifier to detect the concentration of various types of resin gasification products. The circumference of the gasifier is divided into multiple sector-shaped microwave radiation zones, which emit microwaves in a time-sequential rotation manner. The microwave power density of each sector-shaped microwave radiation zone is dynamically adjusted according to the three-dimensional temperature field distribution. A pulsed microwave heating strategy was established to adjust the microwave heating pulse parameters based on the detected concentration change rate of the resin vaporization product components. Adopting dual-frequency microwave synergistic heating mechanism, low-frequency microwaves heat the circuit board resin deeply, and high-frequency microwaves heat the surface of the circuit board resin; Construct a convection exhaust mechanism for the gasifier, introduce gas from one end of the gasifier, control the gas flow rate and preheat the gas, and extract the gasified resin gas with negative pressure at the other end.

2. The method for precise and continuous gasification of circuit board resin based on reaction kinetics control according to claim 1, characterized in that: A multi-point temperature sensor array is evenly deployed on the inner wall of the gasifier in a horizontal layered layout to form a three-dimensional temperature measurement grid. The collected temperature data is used to construct a continuous temperature field distribution function through a three-dimensional interpolation algorithm to obtain a three-dimensional temperature field distribution. An infrared spectroscopy flue gas analyzer is installed at the exhaust port of the gasifier. The infrared spectroscopy flue gas analyzer continuously monitors the concentration of each component of the resin gasification product at a fixed sampling frequency. By establishing the first-order derivative and second-order derivative of the time series of the concentration of the resin gasification product components, the rate change and acceleration characteristics of the resin gasification reaction are evaluated in real time.

3. The method for precise and continuous gasification of circuit board resin based on reaction kinetics control according to claim 2, characterized in that: The circumference of the gasifier is evenly divided into multiple sector-shaped microwave radiation zones along the radial direction. Each sector-shaped microwave radiation zone is equipped with an independent microwave energy feeding device at the corresponding position on the outer wall of the gasifier to heat the circuit board in the gasifier. The magnetrons of each sector-shaped microwave radiation zone are adjusted by an independent power control unit, the sector-shaped microwave radiation zones are numbered, and the microwave transmission power of each sector-shaped microwave radiation zone is adjusted according to the number; A time-rotating microwave transmission mechanism is constructed for simultaneous operation of multiple sectors. Multiple non-adjacent sector-shaped microwave radiation areas are selected to transmit microwaves simultaneously in each working cycle. When multiple sectors in the current cycle complete the microwave transmission work, the adjacent multiple sectors take over the microwave transmission work.

4. The method for precise and continuous gasification of circuit board resin based on reaction kinetics control according to claim 3, characterized in that: A microwave power density regulation algorithm based on the radial-axial temperature field feedback of the gasifier is established; the temperature field data of the gasifier is mapped to each sector-shaped microwave radiation zone; the average temperature distribution of the sector at different altitude layers is calculated, and the volume average temperature of the sector is calculated. The target temperature and temperature deviation are defined, and the microwave power density is regulated using an adaptive proportional-integral-differential control law.

5. The method for precise and continuous gasification of circuit board resin based on reaction kinetics control according to claim 4, characterized in that: Dynamically optimize the power allocation strategy based on the first-order derivative and second-order derivative of the flue gas component concentration; calculate the first-order derivative of the resin gasification product component concentration based on the obtained resin gasification product component concentration to characterize the gasification reaction rate; and calculation of second-order derivatives to characterize reaction acceleration; Construct comprehensive gasification dynamic indicators and adjust microwave power according to the comprehensive gasification dynamic indicators.

6. The method for precise and continuous gasification of circuit board resin based on reaction kinetics control according to claim 5, characterized in that: Establish a pulsed microwave heating strategy and replace the continuous microwave heating mode with an intermittent pulse heating mode; Define the pulse parameters of the microwave pulse train for a single sector, including pulse width, pulse interval, pulse power peak and pulse duty cycle; The pulsed microwave heating is carried out by alternating periodic energy input and heat diffusion processes; the pulse parameters of the pulsed microwave heating are adjusted based on the concentration change rate of the resin gasification product components.

7. The method for precise and continuous gasification of circuit board resin based on reaction kinetics control according to claim 6, characterized in that: A heat accumulation protection algorithm is established to monitor the heat accumulation effect during the resin gasification process. A local heat accumulation index is defined. When the local heat accumulation index exceeds the critical value, a cooling interval is inserted to extend the pulse interval of the sector. A phase coordination control mechanism for microwave pulse sequences is established to avoid electromagnetic interference and power fluctuations caused by multiple sector pulses reaching peak values ​​at the same time through phase staggering.

8. The method for precise and continuous gasification of circuit board resin based on reaction kinetics control according to claim 7, characterized in that: Construct a dual-frequency microwave collaborative heating mechanism, configuring a dual-frequency magnetron combination in each sector-shaped microwave radiation zone, including a low-frequency magnetron and a high-frequency magnetron, to uniformly heat the resin of the circuit board using low-frequency microwaves and high-frequency microwaves; Time division multiplexing technology is used for coordinated control to avoid mutual interference between the two frequencies of microwaves.

9. The method for precise and continuous gasification of circuit board resin based on reaction kinetics control according to claim 8, characterized in that: Preheated carrier gas is delivered to the gas inlet end of the gasifier and preheated by a spiral tube electric heater; a negative pressure suction device is installed at the exhaust end of the gasifier, and the exhaust end pipeline adopts an insulation design to maintain the pipeline temperature within the predetermined range; A convection circulation control mechanism is established inside the gasifier. By adjusting the matching relationship between the carrier gas inlet flow rate and the exhaust negative pressure, an axial convection field is formed inside the furnace. At the same time, the carrier gas passage time in the furnace is controlled by adjusting the air flow rate inside the furnace.

10. A precise and continuous gasification system for circuit board resin based on reaction kinetics control, which is used to implement the precise and continuous gasification method for circuit board resin based on reaction kinetics control according to any one of claims 1 to 9, characterized in that: include: Data acquisition module, multi-sector microwave emission module, pulsed microwave heating module, dual-frequency microwave heating module and resin gasification circulation module; The data acquisition module evenly deploys a multi-point temperature sensor array on the inner wall of the gasifier to obtain the three-dimensional temperature field distribution in the gasifier, and installs a multi-component flue gas analyzer at the exhaust port of the gasifier to detect the concentration of multiple types of resin gasification product components; The multi-sector microwave emission module divides the circumference of the gasifier into multiple sector-shaped microwave radiation zones. The sector-shaped microwave radiation zones emit microwaves in a time-sequential rotation manner, and dynamically adjust the microwave power density of each sector-shaped microwave radiation zone according to the three-dimensional temperature field distribution; The pulse microwave heating module establishes a pulse microwave heating strategy and adjusts the microwave heating pulse parameters according to the detected concentration change rate of the resin gasification product component; The dual-frequency microwave heating module adopts a dual-frequency microwave synergistic heating mechanism, where low-frequency microwaves heat the circuit board resin in depth, and high-frequency microwaves heat the circuit board resin on the surface. The resin gasification circulation module is used to construct a convection exhaust mechanism of the gasifier, introduce gas from one end of the gasifier, control the flow rate of the introduced gas and preheat the introduced gas, and suck the gasified resin gas with negative pressure at the other end.

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