An intermittent spraying device and method for VOCs devolatilization and odor removal system

Abstract

The application discloses an intermittent spraying device and method for a VOCs devolatilization and odor removal system, and belongs to the technical field of VOCs devolatilization and odor removal of high polymer materials. The VOCs devolatilization and odor removal system comprises at least three parallelly arranged heating and odor removal bins, air-cooling bins, negative pressure circulation units, heating units and PLC general control units. Each heating and odor removal bin can independently execute cyclic feeding, negative pressure dynamic cyclic heating and odor removal operations, and can independently transfer the processed materials to the air-cooling bins. The spraying device comprises spraying execution mechanisms arranged in correspondence with the heating and odor removal bins, and a central control module in communication connection with the spraying execution mechanisms and the PLC general control unit. Each spraying execution mechanism comprises a liquid storage tank, a liquid metering unit, a pressurized atomization unit, an intermittent control unit, a material temperature linkage unit and a self-adaptive adjustment unit which are sequentially connected in a pipeline. The application can realize multi-bin linkage precise spraying, stably improve the VOCs removal effect, reduce energy consumption and realize continuous and efficient production.

Description

Technical Field

[0001] This invention belongs to the field of VOCs deodorization and descaling technology of polymer materials, specifically an intermittent spray device and method for VOCs deodorization and descaling systems. Background Technology

[0002] With the continuous improvement of environmental protection requirements for polymer materials in industries such as automotive interiors, food packaging, and home appliances, the residual amount of volatile organic compounds (VOCs) and odor level in plastic granules have become core quality control indicators for materials. At present, the industry generally adopts multi-compartment circulating heating deodorization and deodorization systems to treat plastic granules in order to reduce VOCs residue and meet relevant standard requirements.

[0003] Existing VOCs deodorization systems are equipped with spray devices that primarily function to accelerate the release of small free VOCs molecules from materials by spraying auxiliary liquids to improve deodorization efficiency. However, these devices suffer from several key drawbacks in practical applications: First, they often employ continuous spraying, which cannot be adapted to different process stages such as pre-treatment before heating, isothermal control, and cooling of materials. This can lead to problems like low-temperature spraying delaying material heating and excessive spraying increasing heating energy consumption, resulting in poor stability of the deodorization effect. Second, they use fixed-parameter operating modes, which cannot adaptively match spray parameters based on different material types, loading volumes, and deodorization durations. This requires repeated manual adjustments, resulting in poor adaptability and difficulty in meeting the needs of PP, TPV, and ABS materials. The system has several drawbacks: First, it cannot meet the volatilization requirements of various types of materials. Second, the spray control is not linked to the real-time temperature of the materials and the negative pressure circulation and turning process, which can easily lead to problems such as overheating and melting of materials, uneven spray coverage, resulting in a decline in material properties and incomplete volatilization. Third, it cannot adapt to the asynchronous operation mode of multi-compartment circulation systems, making it difficult to achieve independent spray control of each heating and deodorizing compartment. It is also prone to conflicts with the system's feeding, heating, and transfer processes, affecting the efficiency of continuous production.

[0004] Therefore, the development of an intermittent spraying device and method that can deeply coordinate with a multi-compartment circulating devouring system and achieve full-process adaptive adjustment is necessary to solve the above technical problems. Summary of the Invention

[0005] To address the above problems, this invention provides an intermittent spray device and method for a VOCs deodorization system, which solves the technical problems in the background art.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] An intermittent spray device for a VOCs deodorization system, the VOCs deodorization system comprising at least three parallel heating deodorization chambers, an air-cooled cooling chamber, a negative pressure circulation unit, a heating unit, and a PLC central control unit, each heating deodorization chamber can independently perform circulating feeding and negative pressure dynamic circulating heating deodorization operations, and can independently transfer the processed material to the air-cooled cooling chamber;

[0008] The spray device includes a spray actuator corresponding to each heating and deodorizing chamber, and a central control module that is communicatively connected to both the spray actuator and the PLC control unit.

[0009] Each spray actuator includes a storage tank, a liquid metering unit, a pressurized atomizing unit, an intermittent control unit, a material temperature linkage unit, and an adaptive adjustment unit, which are connected in sequence by pipelines.

[0010] The intermittent control unit, material temperature linkage unit, and adaptive adjustment unit are all electrically connected to the central control module.

[0011] The liquid metering unit is used to quantitatively supply devolatilization auxiliary liquid;

[0012] The pressurized atomization unit is used to atomize the liquid and spray it onto the surface of the material in the chamber.

[0013] The intermittent control unit is used to receive heating stage, material level and transfer signals from the PLC main control unit, and control the intermittent start and stop and parameter switching of the spray actuator;

[0014] The material temperature linkage unit is used to collect the real-time temperature of the material and output temperature trigger and over-temperature protection signals to the central control module to form a closed-loop regulation.

[0015] The adaptive adjustment unit has a built-in material parameter storage module. It interacts with the PLC control unit and the material temperature linkage unit through the central control module and outputs adjustment commands to the central control module. The central control module drives each execution unit to complete the adaptation action, realizing the full-process matching of spraying process with material characteristics and system operating conditions.

[0016] As a further improvement to the above solution, the VOCs deodorization system includes a heating deodorization chamber A, a heating deodorization chamber B, a heating deodorization chamber C, and an air-cooled cooling chamber D. The PLC central control unit controls the system to cyclically feed materials in the order of A→B→C. When any heating deodorization chamber reaches a low material level, it automatically starts heating and negative pressure dynamic circulation. When it reaches a high material level, it stops feeding materials and switches to the next chamber for feeding. After each heating deodorization chamber independently completes heating and deodorization, it independently transfers the material to the air-cooled cooling chamber D for air cooling and batch homogenization. The material transfer and cooling process is synchronized with the heating and deodorization process of the other heating deodorization chambers.

[0017] As a further improvement to the above solution, the liquid metering unit includes a precision metering pump and a flow sensor. The inlet of the precision metering pump is connected to the liquid storage tank, and the outlet is connected to the pressurized atomizing unit. The flow sensor is electrically connected to the central control module to collect the liquid delivery flow rate in real time and feed it back to the central control module, so as to achieve precise control of the total spray volume and the single spray volume of a single chamber. The pressurized atomizing unit includes a pressurizing pump and at least one set of atomizing nozzles. The inlet of the pressurizing pump is connected to the liquid metering unit, and the outlet is connected to the atomizing nozzles. The atomizing nozzles are fixedly installed on the top of the corresponding heating and deodorizing chamber, and the nozzle spray direction is adapted to the turning trajectory of the material in the chamber under negative pressure dynamic circulation. The atomized liquid can be sprayed to fully cover the surface of the dynamically turning material.

[0018] As a further improvement to the above solution, the material temperature linkage unit includes at least three sets of PT100 temperature sensors spaced apart along the height direction of the heating and deodorizing chamber. The three sets of temperature sensors are respectively installed in the upper, middle and lower sections of the heating and deodorizing chamber to collect the material temperature at different locations in the chamber in real time and transmit it to the central control module. The closed-loop control logic of the material temperature linkage unit is as follows: when the real-time material temperature is ≥ the preset devolatilization start threshold T1, the central control module triggers the corresponding spray actuator to start intermittent spraying. When the real-time material temperature is > the preset melting protection threshold T2, the central control module immediately controls the spray actuator to stop spraying. When the material temperature drops below T1, the intermittent spraying is automatically resumed.

[0019] As a further improvement to the above scheme, the static correction logic of the adaptive adjustment unit is as follows: the adaptive adjustment unit receives the actual loading amount of a single bin, the set constant temperature desiccation time, and the initial state parameters of incoming material sent by the PLC control unit, and completes the benchmark parameter correction according to the rule that the actual total spray volume of a single bin = the benchmark total spray volume × (actual loading amount / rated loading amount of bin) and the real-time benchmark spray interval = the original benchmark spray interval × (set constant temperature desiccation time / standard desiccation time), and the amplitude of all statically corrected parameters does not exceed ±50% of the benchmark parameters.

[0020] As a further improvement to the above scheme, the dynamic closed-loop adjustment logic of the adaptive adjustment unit is as follows: the adaptive adjustment unit receives the average temperature of the material in the bin collected by the material temperature linkage unit in real time, and uses the real-time reference spray interval after static correction as the reference, and linearly adjusts the spray interval according to the formula real-time spray interval = real-time reference spray interval × K, where K is the dynamic adjustment coefficient, K = real-time material average temperature / set constant temperature target value. When the real-time material average temperature is higher than the set constant temperature target value, K > 1, the real-time spray interval is extended and the spray frequency is reduced. When the real-time material average temperature is lower than the set constant temperature target value, K < 1, the real-time spray interval is shortened and the spray frequency is increased. The dynamic adjustment is set with an adjustment dead zone of ±2℃. The adjustment is not initiated when the material temperature deviation is within the dead zone range. The maximum adjustment range of the real-time spray interval does not exceed ±50% of the real-time reference spray interval.

[0021] As a further improvement to the above solution, the adaptive adjustment unit receives the material negative pressure dynamic cycle turning signal sent by the PLC central control unit in real time, and automatically matches the spray interval with the material turning cycle, so that each time the material completes a full-warehouse negative pressure cycle turning, a spray operation is performed. At the same time, it has built-in graded over-temperature protection adjustment logic and multi-material orientation adaptation logic, which can complete the corresponding protection action and parameter adaptation according to the material type and real-time working conditions.

[0022] An intermittent spraying method for a VOCs deodorization system, based on an intermittent spraying device, is disclosed. This method coordinates seamlessly with the VOCs deodorization system's circulating feeding, negative pressure dynamic circulating heating, material transfer, and air-cooling processes. Differentiated intermittent spraying is performed according to three stages: the material heating phase, the constant temperature phase, and the pre-cooling pretreatment phase. The spraying interval is synchronized with the material's negative pressure circulating turning cycle, and the spraying frequency is dynamically and adaptively adjusted according to the real-time temperature of the material within the storage chamber. The method specifically includes the following steps:

[0023] S1 Parameter Matching and Static Correction: The type of material to be processed is input through the PLC central control unit. The adaptive adjustment unit retrieves the corresponding benchmark intermittent spray parameter set from the material parameter storage module, combines it with the real-time operating conditions of the system to complete the static correction, and outputs the appropriate benchmark operating parameters.

[0024] S2 Heating Standby: When the material is in the heating period, if the real-time temperature of the material is lower than the devolatilization start threshold T1, the spray actuator of the corresponding heating and deodorizing chamber will stop spraying and standby.

[0025] S3 Constant Temperature Period Dynamic Adaptive Adjustment: When the material enters the constant temperature period and the real-time temperature reaches the devolatilization start threshold T1, intermittent spraying is started. The adaptive adjustment unit collects the average temperature of the material in real time and adjusts the spraying operation parameters linearly according to the set logic. It synchronously matches the material negative pressure circulation and turning cycle to realize the dynamic adaptive adjustment of the spraying frequency with the material temperature. When the material temperature exceeds the melting protection threshold T2, the graded over-temperature protection logic is triggered synchronously.

[0026] S4 Pre-cooling treatment: When the material completes constant temperature volatilization and enters the pre-cooling treatment period, the spray actuator automatically switches to a short-time, short-interval spray mode.

[0027] S5 Transfer Stop and Multi-Compartment Cycle: When the material in the corresponding heating and deodorizing compartment is processed and transferred to the air-cooled cooling compartment, the spray actuator resets and stands by. The system repeats the above steps according to the cycle feeding rhythm to realize independent asynchronous intermittent spray control of multiple compartments.

[0028] As a further improvement to the above scheme, the intermittent spray operation parameters include: the devolatilization start-up threshold T1 is 80-100℃, the melt protection threshold T2 is 130-135℃, and the total spray volume per chamber is 1-10KG. The spray operation parameters during the constant temperature period are a spray duration of 5-20s and a spray interval of 20-60s, and the spray operation parameters during the pretreatment period before cooling are a spray duration of 3-10s and a spray interval of 10-30s.

[0029] As a further improvement to the above scheme, in step S3, the adaptively adjusted real-time spray interval changes linearly with the ratio of the set constant temperature value to the real-time material temperature. When the material temperature is higher than the set constant temperature value, the spray interval is extended; when the material temperature is lower than the set constant temperature value, the spray interval is shortened. This ensures the devolatilization effect while avoiding overheating and melting of the material, thus maintaining a balance between devolatilization efficiency and material properties.

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0031] 1. In this invention, the spray mechanism of each heating chamber is linked with the material level and transfer signal of the main system PLC. It automatically stands up when feeding, starts accurately during the constant temperature period, and stops and resets immediately during transfer. It runs in the A→B→C cycle rhythm throughout the process, without affecting the feeding and transfer efficiency, and the production capacity is stable.

[0032] 2. The spraying and heating stages and the material turning cycle are synchronized. No spraying is performed during the heating period, and spraying is performed as needed during the constant temperature period. This ensures that the volatilization liquid evenly covers the surface of the dynamic material, and the VOCs removal effect is stable and reliable. At the same time, it reduces ineffective spraying and heat loss, reduces energy consumption and auxiliary material consumption, and ensures stable batch quality.

[0033] 3. The spraying device is interconnected with the main system. When changing materials, you only need to select the material type, and the adaptive adjustment unit can automatically retrieve and correct the parameters. During operation, the spraying frequency is dynamically adjusted according to the real-time material temperature and negative pressure cycle, which greatly reduces the reliance on professional personnel.

[0034] 4. The spray start / stop and frequency are automatically adjusted according to the material temperature. The frequency is reduced in advance before the temperature exceeds the limit, and the spray is stopped immediately when the temperature exceeds the limit. It is linked with the main system heating protection to form a double protection, which can completely avoid the material from overheating, melting, clumping and degradation, protect the material performance to the maximum extent and eliminate the risk of the entire warehouse being scrapped.

[0035] 5. The A, B, and C compartment spraying mechanisms operate and adjust independently, and can be in different processes such as heating, constant temperature, and transfer, without interfering with each other. This enables parallel operation of feeding, heating, spraying, and cooling, allowing for continuous 24-hour production without interruption and fully leveraging the capacity advantages of the multi-compartment system. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of a four-tank VOCs deodorization system adapted to the intermittent spray device in this invention.

[0037] Figure 2 This is a schematic diagram of the intermittent spraying method in this invention.

[0038] In the diagram: 1. Vibrating screen; 2. Feed hopper; 3. Inlet air pump; 4. Steam nozzle; 5. Circulating air pump. Detailed Implementation

[0039] To enable those skilled in the art to better understand the technical solution, the present invention will be described in detail below with reference to embodiments. The description in this part is only exemplary and explanatory, and should not be used to limit the scope of protection of the present invention in any way.

[0040] The intermittent spraying device of the present invention is adapted to, for example Figure 1 The four-tank VOCs deodorization system shown consists of three 5m³ double-layer deodorization chambers (A, B, and C) and one 5m³ cooling chamber (D). The complete material handling process is as follows:

[0041] In the feeding process, after the material to be processed is removed by the vibrating screen 1 and the receiving hopper 2, it is fed into each deodorization hopper sequentially by the inlet air pump 3 through the conveying pipeline in a cyclical order of A→B→C→A. When the material in a hopper reaches the low level, the hopper automatically starts heating and circulation; when it reaches the high level, feeding to that hopper stops, and the feed automatically switches to the next hopper to continue feeding, realizing continuous cyclic feeding.

[0042] Taking bin A as an example, the negative pressure circulating heating and volatilization process in bin A involves the following steps: When the material level in bin A reaches a low point, the circulating air pump 5 in bin A starts, driving the material in the bin to form a negative pressure dynamic circulation and tumbling through the pipeline; the steam nozzles 4 in the bin simultaneously provide heat, ensuring that the material is evenly heated during continuous circulation and tumbling, accelerating the precipitation of small VOC molecules. The circulating heating and volatilization principle in bins B and C is completely the same as that in bin A. Each bin operates independently, with independent control of heating time and temperature, without interference between them.

[0043] After any of the deodorization chambers A, B, or C completes the set heating and volatilization process, the system automatically and quickly transfers the material from that chamber to the air-cooled cooling chamber D. The material undergoes dynamic air-cooling and batch homogenization in chamber D to ensure stable performance before being discharged.

[0044] The overall system operates in a cycle from A to B to C to A. Each compartment can be in different processes such as feeding, heating, deodorization, and waiting for transfer, achieving 24-hour continuous production. The inlet air pump, the circulating air pumps of each compartment, the steam nozzles, the transfer mechanism, and the cooling mechanism of compartment D work together under the unified control of PLC to form a complete and stable automated VOC deodorization production line.

[0045] Example 1

[0046] This embodiment provides an intermittent spray device for a VOCs deodorization system, including three sets of spray actuators respectively set for three heating deodorization chambers A, B, and C, and a central control module that is communicatively connected to the three sets of spray actuators and the PLC control unit.

[0047] Each spray actuator includes a liquid storage tank, a liquid metering unit, and a pressurized atomizing unit, all connected sequentially by 304 stainless steel pipes. It also includes an intermittent control unit, a material temperature linkage unit, and an adaptive adjustment unit. The intermittent control unit, the material temperature linkage unit, and the adaptive adjustment unit are all electrically connected to the central control module.

[0048] Liquid metering unit: The precision metering pump adopts a mechanical diaphragm metering pump with a rated flow rate of 0-5L / min, a metering accuracy of ±0.5%, and a working pressure of 0.3-0.8MPa; the flow sensor adopts a turbine flow sensor with a measurement range of 0.1-10L / min and outputs a 4-20mA analog signal to the central control module.

[0049] Pressurized atomization unit: The pressurization pump adopts a stainless steel plunger pump with a rated pressure of 1.0MPa and a flow rate of 10L / min; the atomizing nozzle adopts a 304 stainless steel solid cone nozzle with a spray angle of 60°, a single nozzle flow rate of 0.5-2L / min, and an atomized particle size of 50-100μm. Each chamber is equipped with 3 sets, arranged in an equilateral triangle on the top of the chamber to achieve full coverage spraying of materials inside the chamber.

[0050] Material temperature linkage unit: The PT100 temperature sensor adopts Class A accuracy, with a temperature measurement range of -20-200℃ and a response time of ≤0.5s. It is deployed at 1.5m intervals along the height of the silo, corresponding to the material layers in the upper, middle and lower sections of the silo.

[0051] Adaptive control unit: adopts Siemens SIMATIC S7-1200 process module, with built-in 16G storage module, pre-stores reference parameter sets of 20+ mainstream materials, calculation cycle ≤10ms, and supports Modbus TCP / IP and PROFINET communication protocols.

[0052] Central control module: adopts Siemens S7-1500 PLC, and realizes real-time communication with adaptive adjustment unit and PLC master control unit, with command response delay ≤10ms.

[0053] The intermittent control unit has a built-in industrial-grade two-position two-way solenoid valve with a response time of ≤50ms. It communicates with the PLC central control unit in real time and can receive heating stage signals, material level signals and transfer signals sent by the PLC central control unit. Under the instructions of the central control module, it controls the intermittent start and stop and the switching of operating parameters of the corresponding spray actuator.

[0054] Example 2

[0055] This embodiment provides an intermittent spraying method for a VOCs deodorization system, based on the intermittent spraying device described in Embodiment 1. It is adapted to a 5-ton four-tank VOCs deodorization system (A, B, and C heated deodorization chambers and D air-cooled cooling chamber), using PP material for automotive interiors as the treatment target. The specific steps are as follows:

[0056] S1 Parameter Matching and Static Correction: Before system startup, the operator selects the material to be processed as PP material for automotive interiors through the human-machine interface of the PLC control unit. The adaptive adjustment unit retrieves the corresponding benchmark intermittent spray parameter set from the built-in material parameter storage module. The specific parameters are: devolatilization start threshold T1 = 90℃, melt protection threshold T2 = 132℃; when the rated load of the bin is 5 tons, the corresponding total spray volume of a single bin is 5KG; when the standard devolatilization time is 2 hours, the benchmark spray time during the constant temperature period is 10s and the benchmark spray interval is 30s, and the benchmark spray time during the pretreatment period before cooling is 5s and the benchmark spray interval is 15s; the target value for constant temperature devolatilization is set to 120℃. Subsequently, the adaptive adjustment unit receives the operating parameters of the A heating and deodorizing bin sent by the PLC control unit in real time, including the actual load of 4 tons, the set constant temperature devolatilization time of 2.5 hours, the initial temperature of the incoming material of 50℃, and the moisture content of the incoming material of 0.15%, and completes the static parameter correction according to the preset logic. The specific correction process is as follows:

[0057] Actual total spray volume per bin = baseline total spray volume × (actual loading volume / bin rated loading volume) = 5KG × (4 tons / 5 tons) = 4KG;

[0058] Real-time baseline spray interval = original baseline spray interval × (set constant temperature volatilization time / standard volatilization time) = 30s × (2.5 hours / 2 hours) = 37.5s;

[0059] Testing revealed that the initial temperature and moisture content of the incoming material met the preset standard range, requiring no adjustment of the temperature threshold or other parameters. After correction, the adaptive adjustment unit synchronously outputs the adapted baseline operating parameters to the central control module, PLC control unit, and each spray actuator, preparing for subsequent spraying operations.

[0060] S2 Heating Standby: The PLC central control unit controls the A heating and deodorizing chamber to start feeding material according to the A→B→C cycle feeding logic. When the material in chamber A reaches the low material level threshold, the system automatically starts the heating unit and the negative pressure circulation unit, and the material enters the early stage of heating and volatilization. At this time, the real-time temperature of the material in chamber A collected by the material temperature linkage unit is lower than the volatilization start threshold T1 (90℃). Based on this temperature signal, the central control module controls the corresponding spray actuator in chamber A to be in a stop-spray standby state, avoiding the low-temperature spray from slowing down the material heating rate, effectively reducing the system heating energy consumption, and ensuring that the material quickly reaches the constant temperature volatilization temperature.

[0061] S3 Constant Temperature Period Dynamic Adaptive Adjustment: When the average temperature of the material in the upper, middle, and lower sections of bin A, collected by the material temperature linkage unit, rises to 90℃, the material enters the constant temperature devolatilization period. The central control module triggers the spray actuator in bin A to start intermittent spraying, and the adaptive adjustment unit simultaneously starts dynamic closed-loop adjustment, adjusting the spray parameters according to the real-time working conditions of the material throughout the process. The specific adjustment actions are as follows:

[0062] Temperature-linked regulation: The adaptive regulation unit receives the material temperatures of the upper, middle, and lower sections of bin A from the material temperature linkage unit in real time, calculates the average material temperature, and linearly adjusts the spray interval according to the formula "real-time spray interval = 37.5s × (real-time average temperature / 120℃)". At the same time, a ±2℃ adjustment dead zone is set. When the deviation between the average material temperature and the set constant temperature target value (120℃) is within the dead zone, the regulation will not be initiated to ensure regulation stability, and the maximum adjustment range of the real-time spray interval will not exceed ±50% of the reference value.

[0063] When the real-time average temperature of the material rises to 125℃, the dynamic adjustment coefficient K = 125 / 120 ≈ 1.04, and the real-time spray interval is adjusted to 39s. By extending the spray interval, the spray frequency is reduced, thus preventing the material temperature from continuing to rise.

[0064] When the real-time average temperature of the material drops to 115℃, the dynamic adjustment coefficient K=115 / 120≈0.96, and the real-time spray interval is adjusted to 36s. By shortening the spray interval, the spray frequency is increased, thereby enhancing the VOCs removal effect.

[0065] Negative pressure cycle linkage adjustment: The adaptive adjustment unit receives the material negative pressure dynamic cycle turning cycle signal sent by the PLC central control unit in real time. When the material turning cycle is adjusted from 37.5s to 40s, the spray interval is automatically corrected to 40s. This ensures that a spray operation is performed once for each full-warehouse negative pressure cycle turning of the material, ensuring that the devolatilization auxiliary liquid evenly covers the surface of each batch of dynamically turned fresh material, and avoiding the problem of uneven devolatilization caused by the asynchrony between spraying and material turning.

[0066] Tiered over-temperature protection adjustment: When the real-time temperature of the material reaches 129℃ (i.e., T2-3℃, the warning threshold), the adaptive adjustment unit automatically triggers the first-level over-temperature protection, pulling the spray interval to the maximum limit of 56s (150% of the baseline value), while reducing the duration of a single spray to 7s (70% of the baseline value), slowing down the spray frequency and preventing the material temperature from continuing to rise; when the real-time temperature of the material exceeds the melting protection threshold T2 (132℃), a stop spray signal is immediately sent to the central control module to control the spray actuator to terminate the spray until the material temperature drops below 90℃, at which point the spray operation is automatically resumed and the adjustment parameters are readjusted to ensure that the material does not overheat, melt, or degrade.

[0067] S4 Pre-cooling Pretreatment: After the material in Warehouse A completes 2.5 hours of constant temperature volatilization, the system automatically switches to the pre-cooling pretreatment period. The central control module controls the spray actuator in Warehouse A to automatically switch to a short-time, short-interval spray mode based on the signal from the PLC control unit. The specific parameters are a spray duration of 5 seconds and a spray interval of 15 seconds. This mode further precipitates the small molecules of residual VOCs in the material, reducing the secondary residue of VOCs during the subsequent air-cooling process, and preparing the material for subsequent air-cooling and batch homogenization.

[0068] S5 Transfer Shutdown: After the material in Warehouse A completes the entire process of heating, deodorizing, and pre-treatment before cooling, the PLC central control unit sends a material transfer signal to control the material in Warehouse A to be transported to the air-cooled cooling chamber D through the transfer pipeline. At the same time, the central control module receives the transfer signal and immediately controls the corresponding spray actuator in Warehouse A to terminate the spraying operation and reset to the initial standby state, waiting for the next round of feeding and devolatilization cycle.

[0069] Multi-compartment cyclic execution: Following the cyclic feeding and heating rhythm of the VOCs deodorization system A→B→C, when compartment A enters the material transfer and standby state, compartment B has completed feeding and entered the heating period, and compartment C is in the waiting feeding state. Compartments B and C repeat the above steps S2-S5 in sequence to achieve independent asynchronous intermittent spray control of the three heating and deodorization compartments A, B, and C, ensuring seamless connection of each process in the system, realizing 24-hour continuous production, and giving full play to the capacity advantage of the multi-compartment system.

[0070] In this invention, the devolatilization start threshold T1 is the lowest temperature threshold at which the material begins devolatilization treatment, and the melt protection threshold T2 is the critical temperature threshold at which the material avoids melting / degradation. T2 > T1, and the specific value is preset in the PLC control unit according to the material type. The graded over-temperature protection logic uses the melt protection threshold T2 as the core judgment basis, including a first-level protection of the warning threshold (T2-3℃) and a two-level logic of stop spraying protection of the T2 threshold, to ensure that the material does not overheat and melt or degrade during the devolatilization process.

[0071] Example 3

[0072] The only difference between this embodiment and Embodiment 2 is that the material to be treated is ABS / PC alloy material for automotive interiors. The baseline parameters retrieved by the adaptive adjustment unit are: devolatilization start threshold T1 = 95℃, melt protection threshold T2 = 135℃, rated loading of 5 tons corresponds to a total spray volume of 8KG per chamber, standard devolatilization time of 2 hours corresponds to a baseline spray time of 15s and a baseline spray interval of 40s during the constant temperature period, and a baseline spray time of 8s and a baseline spray interval of 20s during the pretreatment period before cooling. The set constant temperature target value is 125℃. The adaptive adjustment unit completes static correction based on the actual loading of 5 tons and the set devolatilization time of 2 hours, without parameter adjustment. During operation, it completes dynamic closed-loop adjustment according to the adjustment logic described in this invention. The remaining steps are completely consistent with Embodiment 2. After treatment in this embodiment, the VOCs removal rate of the material reaches 88.5%, the odor level is 3.0, the melt index change rate is 2.5%, and there is no material agglomeration, which fully complies with the industry standards for automotive interior materials.

[0073] Example 4

[0074] The only difference between this embodiment and Embodiment 2 is that the material to be treated is a highly transparent food-grade PP material that does not contain free small molecules. After the adaptive adjustment unit identifies the material type, it automatically closes the liquid passages of the spray actuators corresponding to the three heating and deodorizing chambers A, B, and C. The device remains in standby mode throughout the process and does not perform any spraying operations. The remaining steps are completely consistent with Embodiment 2.

[0075] To verify the practical application effect of the intermittent spraying device and method described in this invention, parallel control experiments, multi-material compatibility experiments, and continuous production stability experiments were conducted. The specific test results are as follows:

[0076] Experiment 1: Parallel Controlled Test of Core Performance

[0077] Test conditions: 5 tons of automotive interior PP material were used as the treatment object. The constant temperature de-volatileing time was set to 2 hours and the constant temperature target value was 120℃. The same de-volatileing auxiliary liquid and the same four-tank VOCs de-volatileing and deodorization system were used. Only the spray device was changed. Three groups of tests were set up (control group 1 was the existing continuous spray device, control group 2 was the fixed parameter intermittent spray device, and the experimental group was the adaptive intermittent spray device of the present invention). The test results are shown in Table 1.

[0078] Table 1. Results of core performance comparison tests

[0079]

[0080] Experimental conclusion: Compared with the prior art, the present invention improves the VOCs removal rate by more than 27.4%, ensures stable odor level compliance, reduces the impact on material properties by 74.4%, reduces auxiliary liquid consumption by 55.6%, reduces heating energy consumption by 60.8%, and completely solves the problem of material agglomeration, demonstrating significant technological progress.

[0081] Experiment 2 Multi-material compatibility verification test

[0082] To verify the multi-material adaptability of the adaptive adjustment unit of the present invention, five polymer materials with different properties were selected: 30% fiber-reinforced PP, ABS / PC alloy, heat-sensitive PVC, recycled PP material, and food-grade PP. The device and method of the present invention were used to automatically match parameters throughout the process (without manual adjustment). The test results are shown in Table 2.

[0083] Table 2 Results of Multi-Material Compatibility Verification Test

[0084]

[0085] Experimental conclusion: This invention can automatically adapt spray parameters to polymer materials with different characteristics without manual adjustment. The VOCs removal rate of each material after treatment is over 82%, the odor level meets industry requirements, and there is no material agglomeration or deterioration of physical properties, demonstrating excellent adaptability.

[0086] Experiment 3: Industrial Continuous Production Stability Test

[0087] To verify the industrial applicability of the present invention, a 72-hour continuous production test was conducted, processing a total of 12 batches of automotive interior PP materials (5 tons per batch). The system operated without human intervention throughout the entire process, with parameters automatically matched and adjusted by the adaptive adjustment unit. The test results are shown in Table 3.

[0088] Table 3 shows the results of the 72-hour continuous production stability test.

[0089]

[0090] Experimental conclusion: This invention can be stably adapted to industrial-grade continuous production, with minimal performance fluctuations between batches, trouble-free equipment operation, and stable VOCs removal effect and material property protection, demonstrating strong industrial applicability and promotional value.

[0091] It should be noted that, in this document, the terms "comprising," "including," and any other variations are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Specific examples have been used in this document to illustrate the principles and implementation methods of the present invention. These examples are merely for the purpose of helping to understand the method and core ideas of the present invention. The above descriptions are only preferred embodiments of the present invention. It should be pointed out that, due to the limitations of written expression and the objective existence of infinite specific structures, those skilled in the art can make several improvements, modifications, or variations without departing from the principles of the present invention, and can also combine the above technical features in an appropriate manner. These improvements, modifications, variations, or combinations, or the direct application of the concept and technical solution of the present invention to other situations without modification, should all be considered within the scope of protection of the present invention.

Claims

1. An intermittent spray device for a VOCs deodorization system, the VOCs deodorization system comprising at least three parallel-connected heating deodorization chambers, an air-cooled cooling chamber, a negative pressure circulation unit, a heating unit, and a PLC central control unit, wherein each heating deodorization chamber can independently perform circulating feeding and negative pressure dynamic circulating heating deodorization operations, and can independently transfer the processed material to the air-cooled cooling chamber, characterized in that, The spray device includes a spray actuator corresponding to each heating and deodorizing chamber, and a central control module that is communicatively connected to both the spray actuator and the PLC control unit. Each spray actuator includes a storage tank, a liquid metering unit, a pressurized atomizing unit, an intermittent control unit, a material temperature linkage unit, and an adaptive adjustment unit, which are connected in sequence by pipelines. The intermittent control unit, material temperature linkage unit, and adaptive adjustment unit are all electrically connected to the central control module. The liquid metering unit is used to quantitatively supply devolatilization auxiliary liquid; The pressurized atomization unit is used to atomize the liquid and spray it onto the surface of the material in the chamber. The intermittent control unit is used to receive heating stage, material level and transfer signals from the PLC main control unit, and control the intermittent start and stop and parameter switching of the spray actuator; The material temperature linkage unit is used to collect the real-time temperature of the material and output temperature trigger and over-temperature protection signals to the central control module to form a closed-loop regulation. The adaptive adjustment unit has a built-in material parameter storage module. It interacts with the PLC control unit and the material temperature linkage unit through the central control module and outputs adjustment commands to the central control module. The central control module drives each execution unit to complete the adaptation action, realizing the full-process matching of spraying process with material characteristics and system operating conditions.

2. The intermittent spray device for a VOCs deodorization system according to claim 1, characterized in that, The VOCs deodorization system includes heating and deodorization chambers A, B, and C, and air-cooled chamber D. The PLC control unit controls the system to cyclically feed materials in the order of A→B→C. When any heating and deodorization chamber reaches a low material level, it automatically starts heating and negative pressure dynamic circulation. When it reaches a high material level, it stops feeding materials and switches to the next chamber. After each heating and deodorization chamber independently completes heating and deodorization, it independently transfers the material to air-cooled chamber D for air-cooling and batch homogenization. The material transfer and cooling process is synchronized with the heating and deodorization process of the other heating and deodorization chambers.

3. The intermittent spray device for a VOCs deodorization system according to claim 1, characterized in that, The liquid metering unit includes a precision metering pump and a flow sensor. The inlet of the precision metering pump is connected to the liquid storage tank, and the outlet is connected to the pressurized atomizing unit. The flow sensor is electrically connected to the central control module to collect the liquid delivery flow rate in real time and feed it back to the central control module, so as to achieve precise control of the total spray volume and the single spray volume of a single chamber. The pressurized atomizing unit includes a pressurizing pump and at least one set of atomizing nozzles. The inlet of the pressurizing pump is connected to the liquid metering unit, and the outlet is connected to the atomizing nozzles. The atomizing nozzles are fixedly installed on the top of the corresponding heating and deodorizing chamber, and the nozzle spray direction is adapted to the turning trajectory of the material in the chamber under negative pressure dynamic circulation. The atomized liquid can be sprayed to fully cover the surface of the dynamically turning material.

4. The intermittent spray device for a VOCs deodorization system according to claim 1, characterized in that, The material temperature linkage unit includes at least three sets of PT100 temperature sensors spaced apart along the height of the heating and deodorizing chamber. The three sets of temperature sensors are respectively installed in the upper, middle and lower sections of the heating and deodorizing chamber to collect the material temperature at different locations in the chamber in real time and transmit it to the central control module. The closed-loop control logic of the material temperature linkage unit is as follows: when the real-time material temperature is ≥ the preset devolatilization start threshold T1, the central control module triggers the corresponding spray actuator to start intermittent spraying. When the real-time material temperature is > the preset melting protection threshold T2, the central control module immediately controls the spray actuator to stop spraying. When the material temperature drops below T1, the intermittent spraying is automatically resumed.

5. The intermittent spray device for a VOCs deodorization system according to claim 1, characterized in that, The static parameter correction logic of the adaptive adjustment unit is as follows: The adaptive adjustment unit receives the actual loading amount of a single bin, the set constant temperature desiccation time, and the initial state parameters of incoming material sent by the PLC central control unit. It completes the benchmark parameter correction according to the rule that the actual total spray volume of a single bin = benchmark total spray volume × (actual loading amount / rated loading amount of bin) and the real-time benchmark spray interval = original benchmark spray interval × (set constant temperature desiccation time / standard desiccation time). The amplitude of all statically corrected parameters does not exceed ±50% of the benchmark parameters.

6. The intermittent spray device for a VOCs deodorization system according to claim 1, characterized in that, The dynamic closed-loop adjustment logic of the adaptive adjustment unit is as follows: The adaptive adjustment unit receives the average temperature of the material in the silo collected by the material temperature linkage unit in real time, and uses the real-time reference spray interval after static correction as the reference, and linearly adjusts the spray interval according to the formula real-time spray interval = real-time reference spray interval × K, where K is the dynamic adjustment coefficient, K = real-time material average temperature / set constant temperature target value. When the real-time material average temperature is higher than the set constant temperature target value, K > 1, the real-time spray interval is extended and the spray frequency is reduced. When the real-time material average temperature is lower than the set constant temperature target value, K < 1, the real-time spray interval is shortened and the spray frequency is increased. The dynamic adjustment is set with an adjustment dead zone of ±2℃. The adjustment is not initiated when the material temperature deviation is within the dead zone range. The maximum adjustment range of the real-time spray interval does not exceed ±50% of the real-time reference spray interval.

7. The intermittent spray device for a VOCs deodorization system according to claim 1, characterized in that, The adaptive adjustment unit receives the material negative pressure dynamic cycle turning cycle signal sent by the PLC central control unit in real time, and automatically matches the spray interval with the material turning cycle, so that each time the material completes a full-bin negative pressure cycle turning, a spray operation is performed. At the same time, it has built-in graded over-temperature protection adjustment logic and multi-material orientation adaptation logic, which can complete the corresponding protection action and parameter adaptation according to the material type and real-time working conditions.

8. An intermittent spraying method for a VOCs deodorization system, characterized in that, Based on the intermittent spraying device described in any one of claims 1-7, the method is fully coordinated with the VOCs deodorization and odor removal system's circulating feeding, negative pressure dynamic circulating heating, material transfer, and air-cooling cooling processes. Differentiated intermittent spraying is performed according to three stages: the material heating phase, the constant temperature phase, and the pre-treatment phase before cooling. The spraying interval is synchronously matched with the material's negative pressure circulating turning cycle, and the spraying frequency is dynamically and adaptively adjusted according to the real-time temperature of the material in the silo. Specifically, the method includes the following steps: S1 Parameter Matching and Static Correction: The type of material to be processed is input through the PLC central control unit. The adaptive adjustment unit retrieves the corresponding benchmark intermittent spray parameter set from the material parameter storage module, combines it with the real-time operating conditions of the system to complete the static correction, and outputs the appropriate benchmark operating parameters. S2 Heating Standby: When the material is in the heating period, if the real-time temperature of the material is lower than the devolatilization start threshold T1, the spray actuator of the corresponding heating and deodorizing chamber will stop spraying and standby. S3 Constant Temperature Period Dynamic Adaptive Adjustment: When the material enters the constant temperature period and the real-time temperature reaches the devolatilization start threshold T1, intermittent spraying is started. The adaptive adjustment unit collects the average temperature of the material in real time and adjusts the spraying operation parameters linearly according to the set logic. It synchronously matches the material negative pressure circulation and turning cycle to realize the dynamic adaptive adjustment of the spraying frequency with the material temperature. When the material temperature exceeds the melting protection threshold T2, the graded over-temperature protection logic is triggered synchronously. S4 Pre-cooling treatment: When the material completes constant temperature volatilization and enters the pre-cooling treatment period, the spray actuator automatically switches to a short-time, short-interval spray mode. S5 Transfer Stop and Multi-Compartment Cycle: When the material in the corresponding heating and deodorizing compartment is processed and transferred to the air-cooled cooling compartment, the spray actuator resets and stands by. The system repeats the above steps according to the cycle feeding rhythm to realize independent asynchronous intermittent spray control of multiple compartments.

9. The intermittent spraying method for a VOCs deodorization system according to claim 8, characterized in that, The intermittent spray operation parameters include: a devolatilization start-up threshold T1 of 80-100℃, a melt protection threshold T2 of 130-135℃, and a total spray volume of 1-10KG per chamber. The spray operation parameters during the constant temperature period are a spray duration of 5-20s and a spray interval of 20-60s, while the spray operation parameters during the pretreatment period before cooling are a spray duration of 3-10s and a spray interval of 10-30s.

10. The intermittent spraying method for a VOCs deodorization system according to claim 8, characterized in that, In step S3, the adaptively adjusted real-time spray interval changes linearly with the ratio of the set constant temperature value to the real-time material temperature. When the material temperature is higher than the set constant temperature value, the spray interval is extended; when the material temperature is lower than the set constant temperature value, the spray interval is shortened. This ensures the volatilization effect while preventing the material from overheating and melting, thus maintaining a balance between volatilization efficiency and material properties.

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