Waste polyolefin plastic cracking recovery system based on multi-dimensional data monitoring

Abstract

The invention relates to the technical field of plastic cracking, in particular to a waste polyolefin plastic cracking recovery system based on multi-dimensional data monitoring, comprising: a pretreatment unit for crushing, cleaning and drying waste polyolefin plastic to generate a plastic raw material; the acquisition unit is used for acquiring the moisture content of the plastic raw material, the plastic density and the component proportion of each monomer plastic, and performing differential scanning calorimetry and thermogravimetric analysis on a representative plastic raw material sample to obtain thermodynamic parameters; the feeding unit is used for constructing a plastic feeding model and regulating and controlling the feeding amount; the cracking unit is used for matching cracking process parameters and adjusting a cracking reaction kettle; the detection unit is used for detecting cracking process parameters and cracking products; the control unit is used for judging whether the cracking reaction is completed or not and adjusting cracking process parameters; according to the invention, the accuracy of the existing waste polyolefin plastic cracking recovery system is further improved while the plastic cracking process is effectively monitored.

Description

Technical Field

[0001] The present application relates to the field of plastic cracking technology, and in particular to a waste polyolefin plastic cracking and recovery system based on multi-dimensional data monitoring. Background Art

[0002] Waste polyolefin plastics (such as polyethylene and polypropylene) are common waste plastics. They are difficult to degrade naturally, and long-term accumulation will cause serious pollution to the soil, water bodies and ecosystems. Traditional landfill and incineration treatment methods not only occupy a large amount of land resources, but also produce harmful gases and greenhouse gas emissions. With the world's emphasis on sustainable development, how to effectively recycle and reuse waste plastics has become an urgent problem to be solved. Pyrolysis recovery technology can convert waste plastics into high-value-added fuels or chemical raw materials, reduce dependence on primary resources, and realize resource recycling. With the rapid development of sensor technology, automatic control technology and data analysis technology, multi-dimensional data monitoring systems can monitor multi-dimensional data such as temperature, pressure, gas composition, and liquid product composition during the pyrolysis process in real time. These data can be used to optimize pyrolysis conditions, improve pyrolysis efficiency and product quality.

[0003] Chinese patent application publication number: CN117417762A discloses an industrial continuous and precise control method for the pyrolysis of mixed waste plastics in a chamber. The invention provides an industrial continuous and precise control method for the pyrolysis of mixed waste plastics in a chamber. The process is implemented by a pyrolysis system composed of multiple chamber pyrolysis reactors, including the following steps: individually setting the pyrolysis process conditions in each chamber pyrolysis reactor according to the physical and chemical properties of the mixed waste plastics; quantitatively delivering the mixed waste plastics to the chamber pyrolysis reactor through a feeding system according to the proportion of components in the mixed waste plastics; preliminarily estimating the proportion of each monomer plastic in the mixed waste plastics, such as PP, PE, and PVC, through the feeding system, and finely controlling the entire pyrolysis process by using the feed amount and pyrolysis process conditions corresponding to the proportion of each monomer plastic in the mixed waste plastics preset in the system, thereby achieving the goal of regulating the pyrolysis products of the mixed waste plastics, greatly improving the quality of the pyrolysis products of the mixed waste plastics, and increasing their economic added value.

[0004] However, the above method has the following problem: it fails to adjust the cracking parameters by performing a detailed analysis of the cracking products during the reaction. Summary of the Invention

[0005] To this end, the present invention provides a waste polyolefin plastic cracking and recovery system based on multi-dimensional data monitoring, which is used to overcome the problem in the prior art of being able to adjust cracking parameters by performing detailed analysis of cracking products during the reaction process.

[0006] To achieve the above objectives, the present invention provides a waste polyolefin plastic cracking and recovery system based on multidimensional data monitoring, comprising: A pre-treatment unit, which is used to crush, clean and dry waste polyolefin plastics to generate plastic raw materials; a collection unit connected to the pretreatment unit, for collecting the moisture content, plastic density, and composition ratio of each monomer plastic of the plastic raw material, and performing differential scanning calorimetry and thermogravimetric analysis on representative plastic raw material samples to obtain thermodynamic parameters including melting temperature, cracking onset temperature, maximum weight loss rate temperature, and predicted carbon residue rate; A feeding unit connected to the collection unit is used to build a plastic feeding model based on the plastic density and the component ratio, and to control the feeding amount based on the plastic feeding model and the moisture content, and to associate the thermodynamic parameters in real time with the feeding batch corresponding to the sampling period; a cracking unit, connected to the collection unit and the feeding unit, respectively, for matching cracking process parameters according to the plastic feeding model, the moisture content, the feeding amount, and the thermodynamic parameters corresponding to the feeding batch, and adjusting the cracking reactor based on the cracking process parameters; a detection unit connected to the cracking unit, for detecting cracking process parameters of the cracking reactor and cracking products, wherein the cracking process parameters include cracking temperature, cracking pressure and cracking time, and the cracking products include cracking gas, cracking liquid and cracking solid; A control unit is connected to the cracking unit and the detection unit, respectively, for adjusting the cracking process parameters based on the cracking product and determining whether the cracking reaction is completed, and when it is determined that the cracking reaction is completed, recording the cracking process parameters and adjusting the cracking process parameters in combination with the plastic feeding model.

[0007] Furthermore, the acquisition unit includes: a component subunit connected to the pretreatment unit, for determining the component ratio of each monomer plastic of the waste polyolefin plastic based on image analysis and infrared spectroscopy; a measuring subunit, connected to the pre-processing unit, for measuring the density of the plastic based on a density gradient column method and detecting the moisture content by a drying method; The thermal analysis subunit includes a conveyor belt dynamic sampling device, a micro differential scanning calorimeter (DSC) and a thermogravimetric analyzer (TGA) combined device. It obtains the dried plastic raw material flow through a pneumatic sampling valve installed in the middle of the conveyor belt in the conveyor belt dynamic sampling device, generates a representative sample through an automatic reduction device, and conveys it to the micro differential scanning calorimeter (DSC) and thermogravimetric analyzer (TGA) combined device for thermal analysis. Specifically, under a nitrogen atmosphere, a differential scanning calorimetry test procedure is performed: the plastic sample is heated from room temperature to 300°C at a constant heating rate of 20°C / min, and its melting temperature is determined by monitoring the sample absorption / release heat changes; and a thermogravimetric analysis test procedure is performed: the temperature is increased to 600°C at 30°C / min to obtain the cracking starting temperature, the maximum weight loss rate temperature, and the predicted residual carbon rate.

[0008] Furthermore, the feeding unit includes: A modeling subunit, connected to the acquisition unit, for calculating the weight ratio of each monomer plastic according to the plastic density and the component ratio to construct the plastic feeding model; an execution subunit, connected to the acquisition unit and the modeling subunit, respectively, for comparing the moisture content with a preset moisture content, determining whether to start feeding according to the comparison result, and regulating the feed amount based on the weight ratio when it is determined that feeding is started; The preset moisture content is positively correlated with the weight ratio of the polar plastic.

[0009] Furthermore, the cracking unit comprises: a process subunit, connected to the acquisition unit, the feeding unit, and the thermal analysis subunit, respectively, for selecting a plurality of the cracking process parameters of the same plastic density and composition according to the plastic feeding model, calculating a difference value according to the moisture content and the feed amount, and determining optimal cracking process parameters according to the difference value and the thermodynamic parameters; wherein the optimal cracking process parameters include: a temperature curve and time parameters, a reaction pressure setting value, a stirring rate, and a catalyst dosage; wherein the temperature curve and time parameters are dynamically calculated based on the thermodynamic parameters; The regulating subunit is connected to the process subunit and is used to regulate the working parameters of the cracking reactor based on the optimal cracking process parameters.

[0010] Furthermore, the process subunit selects several cracking process parameters of the same plastic density and the same composition according to the plastic feed model, and calculates and generates difference values ​​according to the moisture content and the feed amount, and determines the optimal cracking process parameters according to the difference values ​​and the thermodynamic parameters, including: According to the plastic density difference ≤ ± 0.02g / cm 3and the component ratio difference is ≤±3% and a plurality of candidate groups of cracking process parameters are obtained by preliminary screening from a historical process parameter library; The difference value δ is calculated according to the following formula. Only numerical values ​​are taken during the calculation. The three groups of historical parameters with the smallest difference value δ are taken, and then weighted average is performed to generate the first cracking process parameters; wherein, the difference value ,in is the current moisture content, unit: % is the historical moisture content, unit: % is the current feed amount, unit Kg; is the historical feed amount, unit Kg; The temperature curve and time parameters dynamically calculated according to the thermodynamic parameters are used to replace the temperature curve and time parameters in the first cracking process parameters to obtain the optimal cracking process parameters.

[0011] Furthermore, the temperature curve and time parameters are dynamically calculated based on thermodynamic parameters, including: Based on the cracking starting temperature Tonset, set the end temperature of the initial heating stage: initial end temperature = Tonset -20°C; The temperature of the main reaction zone is set at the maximum weight loss rate temperature Tmax: main reaction temperature = Tmax ± 10°C; Set the final holding temperature according to the predicted carbon residue rate Char: if the predicted carbon residue rate Char is greater than 8%, the final holding temperature = Tmax + 30°C; otherwise, the final holding temperature = Tmax + 10°C; Based on the difference between the melting temperature Tm and the cracking onset temperature Tonset, the homogenization time of the material is calculated: Homogenization time = (Tonset - Tm) × 0.5, unit: min; Main reaction time T = W × 2.5; where the unit of main reaction time T is min, W is the width of the mass loss interval, and only the numerical value is used during calculation. W is specifically the width of the 90% mass loss interval in the thermogravimetric analysis test procedure.

[0012] Furthermore, the detection unit includes: The parameter detection subunit is connected to the cracking unit and is used to insert the temperature measuring end of the thermometer into the center of the material to measure the cracking temperature, and to measure the cracking pressure in the gas phase space above the cracking reactor through a pressure sensitive element.

[0013] Furthermore, the detection unit further includes: The product detection subunit is connected to the cracking unit and is used to detect the long-chain alkane content and benzene concentration of the cracked gas by gas chromatography, measure the viscosity and olefin ratio of the cracked liquid by Brookfield viscometer, and obtain the carbon deposition rate by sampling and detecting the cracked solid on the inner wall of the cracking reactor.

[0014] Furthermore, the control unit includes: a temperature subunit, connected to the cracking unit and the detection unit, respectively, for determining whether to increase the temperature based on the long-chain alkane content, and determining whether to decrease the temperature based on the benzene series concentration; a pressure subunit, connected to the cracking unit and the detection unit, respectively, for comparing the cracking pressure with a preset pressure and determining whether to open the exhaust valve based on the comparison result, wherein the preset pressure is positively correlated with the feed amount of the plastic raw material; a time subunit, connected to the cracking unit and the detection unit, respectively, for comparing the carbon deposition rate with a preset carbon deposition rate and determining whether the cracking reaction is completed based on the comparison result, wherein the preset carbon deposition rate is positively correlated with the feed amount of the plastic raw material; The stirring sub-unit is connected to the cracking unit and the detection unit respectively, and is used to determine whether to reduce the stirring rate based on the olefin ratio, and to determine whether to increase the stirring rate based on the viscosity.

[0015] Furthermore, the temperature subunit is also used to: receiving the reactor weight loss rate data detected in real time by the detection unit and the reactor weight loss rate curve predicted by the thermal analysis subunit through thermogravimetric analysis; Compare the deviation ΔW between the real-time detected reactor weight loss rate and the predicted reactor weight loss rate, and dynamically adjust the main reaction temperature. Only numerical values ​​are used during calculation, including: If ΔW > +5%, temperature rise compensation: ; If ΔW < -5%, temperature compensation: ; in, is the adjusted main reaction temperature, unit: °C; is the main reaction temperature before adjustment, unit is ℃.

[0016] Compared with the prior art, the beneficial effect of the present invention is that the present invention constructs a plastic feeding model by collecting parameters of the original plastic, and regulates the feed amount in combination with the moisture content and the weight ratio of each monomer plastic. In the plastic cracking and recovery process, the properties of the original plastic have an important influence on the cracking process and product distribution. By collecting these parameters, the characteristics of the input material can be better understood. The moisture in the plastic will affect the cracking process. Excessive moisture may cause unstable cracking temperature, increase energy consumption, and may affect the quality and output of the product. By monitoring the moisture content, the feed amount can be adjusted to ensure the stability and efficiency of the cracking process. Waste polyolefin plastics are usually mixed with multiple monomer plastics. Different monomer plastics have different cracking characteristics. Therefore, the feed amount needs to be regulated according to the weight ratio of each monomer plastic. Through multi-dimensional data monitoring, combined with the feed model and parameter control, refined management of the cracking process can be achieved, effectively improving the accuracy of the waste polyolefin plastic cracking and recovery system based on multi-dimensional data monitoring.

[0017] Furthermore, the present invention guides the current cracking process by detecting the parameters of the original plastic and matching the processing parameters with the same parameters in the processing system based on the parameters. By detecting the parameters of the original plastic and matching the processing technology with the same parameters in the past, a basic cracking process parameter group is screened out and then combined with thermodynamic parameters and the difference values ​​calculated based on moisture content and feed amount to further determine the optimal cracking process parameters. The cracking temperature curve and time parameters are dynamically generated completely by thermodynamic parameters, avoiding historical experience deviations and solving the defect of traditional processes relying on fixed temperatures. Therefore, the temperature and time parameters are completely generated by thermal analysis data and are not affected by historical parameters. In traditional cracking processing, it is often necessary to adjust parameters multiple times to find the optimal cracking conditions. This method reduces the trial and error process through experience matching and directly adopts verified process parameters, thereby significantly improving the cracking efficiency. The process parameters based on past experience are usually optimized to ensure that the cracking process is carried out under the lowest energy consumption. Accurate process parameters can avoid the equipment from operating under unsuitable conditions, thereby reducing equipment wear and maintenance costs. This method relies on the detection of original plastic parameters and the analysis of past processing data. It is a data-driven decision-making method. By accumulating a large amount of processing data, the system can continuously optimize the matching algorithm and improve the accuracy of decision-making. By detecting and matching process parameters, the system can flexibly handle waste plastics of different compositions and states, further improving the accuracy of the waste polyolefin plastic cracking and recovery system based on multi-dimensional data monitoring.

[0018] Furthermore, the present invention adjusts the parameters of the cracking process by detecting the product associated with the cracking process parameters. During the cracking process, the composition and yield of the product will be affected by multiple parameters such as cracking temperature, pressure, and feed rate. By detecting the product, the system can understand the effect of the current cracking process in real time and dynamically adjust the cracking parameters according to the actual state of the product. Over-cracking may result in excessive low-value by-products in the product, while under-cracking will result in incomplete conversion of the raw material. By detecting the product and adjusting the cracking parameters, these two situations can be effectively avoided, ensuring that the cracking process is always in the best state. By detecting the product, the system can accurately adjust the cracking parameters according to the requirements of the target product, thereby improving the quality and purity of the product. Some impurities and by-products may be generated during the cracking process. These substances will affect the quality and subsequent application of the product. By real-time monitoring of the product and adjusting the cracking parameters, the generation of these impurities and by-products can be reduced, thereby improving the overall quality of the product. By accurately controlling the cracking process, it can be ensured that the raw material is converted into the target product to the maximum extent, reducing the waste of raw materials caused by incomplete cracking or improper parameters, and further improving the accuracy of the waste polyolefin plastic cracking and recovery system based on multi-dimensional data monitoring.

[0019] Furthermore, the present invention improves the timeliness of monitoring the cracking process by adjusting the cracking-related parameters of the cracking reactor. By adjusting the relevant parameters of the cracking reactor, the system can more quickly obtain real-time data from the cracking process. This real-time monitoring capability enables the system to promptly detect anomalies or deviations during the cracking process and make rapid adjustments. Traditional cracking and recovery systems may be unable to promptly capture key changes in the cracking process due to delays in monitoring equipment or slow data processing speeds. The present invention reduces this lag by optimizing parameter adjustment, ensuring that the system can quickly respond to dynamic changes in the cracking process. By optimizing and adjusting the parameters of the cracking reactor, the system can more accurately control the cracking process. Multidimensional data monitoring combined with parameter adjustment can reduce errors and uncertainties caused by changes in equipment, raw materials, or operating conditions. Traditional cracking and recovery systems may have low cracking efficiency due to unreasonable parameter settings. The present invention avoids ineffective operations and improves cracking efficiency through real-time monitoring and parameter adjustment. Waste polyolefin plastics may have large differences in composition and state. By adjusting the parameters of the cracking reactor, the system can flexibly process different types of plastics, improving the system's versatility and adaptability, and further enhancing the accuracy of the waste polyolefin plastic cracking and recovery system based on multidimensional data monitoring. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] One or more embodiments are exemplarily illustrated by pictures in the corresponding drawings. These exemplifications do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings are represented as similar elements. Unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0021] Figure 1 This is a structural block diagram of the waste polyolefin plastic cracking and recovery system based on multi-dimensional data monitoring of the present invention; Figure 2 This is a structural block diagram of a control unit according to an embodiment of the present invention; Figure 3 This is a logic diagram for determining whether to open the exhaust valve according to an embodiment of the present invention; Figure 4 This is a logic diagram for determining whether a cracking reaction is complete according to an embodiment of the present invention. DETAILED DESCRIPTION

[0022] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0023] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in a sequence other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0024] See also Figure 1 As shown, it is a structural block diagram of a waste polyolefin plastic cracking and recovery system based on multi-dimensional data monitoring of the present invention. An embodiment of the present invention provides a waste polyolefin plastic cracking and recovery system based on multi-dimensional data monitoring, comprising: A pre-treatment unit, which is used to crush, clean and dry waste polyolefin plastics to generate plastic raw materials; a collection unit connected to the pretreatment unit, for collecting the moisture content, plastic density, and composition ratio of each monomer plastic of the plastic raw material, and performing differential scanning calorimetry and thermogravimetric analysis on representative plastic raw material samples to obtain thermodynamic parameters including melting temperature, cracking onset temperature, maximum weight loss rate temperature, and predicted carbon residue rate; A feeding unit connected to the collection unit is used to build a plastic feeding model based on the plastic density and the component ratio, and to control the feeding amount based on the plastic feeding model and the moisture content, and to associate the thermodynamic parameters in real time with the feeding batch corresponding to the sampling period; a cracking unit, connected to the collection unit and the feeding unit, respectively, for matching cracking process parameters according to the plastic feeding model, the moisture content, the feeding amount, and the thermodynamic parameters corresponding to the feeding batch, and adjusting the cracking reactor based on the cracking process parameters; A detection unit connected to the cracking unit is used to detect cracking process parameters of the cracking reactor and cracking products. The cracking process parameters include cracking temperature, cracking pressure and cracking time. The cracking products include cracking gas, cracking liquid and cracking solid. The control unit is connected to the cracking unit and the detection unit respectively, and is used to adjust the cracking process parameters based on the cracking products and determine whether the cracking reaction is completed. When it is determined that the cracking reaction is completed, the cracking process parameters are recorded and the cracking process parameters are adjusted in combination with the plastic feeding model.

[0025] Specifically, the acquisition unit includes: A component subunit, which is connected to the pre-processing unit and is used to determine the composition ratio of each monomer plastic of the waste polyolefin plastic based on image analysis and infrared spectroscopy; a measuring subunit, connected to the pre-processing unit, for measuring the density of the plastic based on a density gradient column method and detecting the moisture content by a drying method; The thermal analysis subunit includes a conveyor belt dynamic sampling device, a micro differential scanning calorimeter (DSC) and a thermogravimetric analyzer (TGA) combined device. It obtains the dried plastic raw material flow through a pneumatic sampling valve installed in the middle of the conveyor belt in the conveyor belt dynamic sampling device, generates a representative sample of a certain mass through an automatic reduction device, and conveys it to the micro differential scanning calorimeter (DSC) and thermogravimetric analyzer (TGA) combined device for thermal analysis. Specifically, under a nitrogen atmosphere, a differential scanning calorimetry test procedure is performed: the plastic sample is heated from room temperature to 300°C at a constant heating rate of 20°C / min, and its melting temperature is determined by monitoring the sample absorption / release heat changes; and a thermogravimetric analysis test procedure is performed: the temperature is increased to 600°C at 30°C / min to obtain the cracking starting temperature, the maximum weight loss rate temperature, and the predicted residual carbon rate. As you can understand, the pre-processing unit first cleans the waste polyolefin plastics, then uses a high-resolution digital camera or industrial camera to capture them from different angles. The images are processed for noise reduction and feature extraction. Using a Fourier transform infrared spectrometer, the collected spectra are compared with the infrared spectra of standard polyolefin plastics to identify characteristic absorption peaks. The results of image analysis and infrared spectroscopy are then combined. Image analysis provides preliminary classification and appearance characteristics, while infrared spectroscopy provides precise chemical composition.

[0026] It is understandable that according to the density range of the plastic to be tested, two appropriate liquids are selected. For plastics with a density of 0.83-0.96g / cm³, a liquid with a density less than 0.83g / cm³ and a liquid with a density greater than 0.96g / cm³ can be selected. For example, the two liquids are: acetone (density 0.7899g / cm³) and saturated salt water (density 1.2g / cm³) or water (density 1g / cm³). Of course, according to actual needs, other two miscible liquids can also be selected. The two liquids are mixed in a certain proportion and poured into the density gradient column. Start with the liquid with lower density and slowly add the liquid with higher density to avoid mixing the liquids. Mark several points of known density on the density gradient column. The positions of these points can be determined by adding standard samples of known density. Gently place the dried plastic sample into the density gradient column to avoid violent collision between the sample and the liquid. After the sample is still, observe its suspension position in the density gradient column. The sample will be suspended in a liquid layer with the same density as its density. According to the suspension position of the sample, read the corresponding density value on the density gradient column. If the sample is suspended between two marked points, its density can be calculated by interpolation.

[0027] Specifically, the feeding unit includes: A modeling subunit, which is connected to the collection unit and is used to calculate the weight ratio of each monomer plastic according to the plastic density and component ratio to build a plastic feeding model; an execution subunit, which is connected to the acquisition unit and the modeling subunit respectively, and is used to compare the moisture content with the preset moisture content, determine whether to start feeding based on the comparison result, and when it is determined that feeding is started, adjust the feeding amount based on the weight ratio; If the moisture content is greater than or equal to the preset moisture content, the feed is determined to be closed; If the moisture content is less than the preset moisture content, it is determined that the feed is started; In a specific embodiment, the preset moisture content is set to 2%. If the moisture content is 4% and is greater than the preset moisture content, it is determined that the feed is shut down. If the moisture content is 1.2% which is less than the preset moisture content, the feed is started; The preset moisture content is positively correlated with the weight ratio of the polar plastic.

[0028] It is understandable that polar plastics have strong water absorption. The greater the weight ratio of polar plastics, the greater the water content. Therefore, the preset water content is positively correlated with the weight ratio of polar plastics.

[0029] Optionally, the preset moisture content range is 2% to 3%.

[0030] Specifically, the present invention constructs a plastic feeding model by collecting parameters of the original plastic, and regulates the feed amount in combination with the moisture content and the weight ratio of each monomer plastic. In the plastic cracking and recovery process, the properties of the original plastic have an important influence on the cracking process and product distribution. By collecting these parameters, the characteristics of the input material can be better understood. The moisture in the plastic will affect the cracking process. Excessive moisture may cause unstable cracking temperature, increase energy consumption, and may affect the quality and output of the product. By monitoring the moisture content, the feed amount can be adjusted to ensure the stability and efficiency of the cracking process. Waste polyolefin plastics are usually mixed with multiple monomer plastics. Different monomer plastics have different cracking characteristics. Therefore, the feed amount needs to be regulated according to the weight ratio of each monomer plastic. Through multi-dimensional data monitoring, combined with the feed model and parameter control, refined management of the cracking process can be achieved, effectively improving the accuracy of the waste polyolefin plastic cracking and recovery system based on multi-dimensional data monitoring.

[0031] Specifically, the cracking unit includes: The process subunit is connected to the collection unit, the feeding unit and the thermal analysis subunit respectively, and is used to select several cracking process parameters of the same plastic density and the same composition according to the plastic feeding model, and calculate and generate difference values ​​according to the moisture content and the feed amount, and determine the optimal cracking process parameters according to the difference values ​​and thermodynamic parameters; The optimal cracking process parameters are determined through system dynamic matching and calculation, and are the core adjustable variable combination that maximizes the cracking efficiency. The optimal cracking process parameters include: temperature curve and time parameters, reaction pressure setting value, stirring rate and catalyst dosage. The temperature curve and time parameters are dynamically calculated based on thermal analysis parameters. The regulating subunit is connected to the process subunit and is used to regulate the working parameters of the cracking reactor based on the optimal cracking process parameters.

[0032] The process subunit selects several cracking process parameters of the same plastic density and composition according to the plastic feed model, calculates and generates difference values ​​according to the moisture content and feed amount, and determines the optimal cracking process parameters according to the difference values ​​and thermodynamic parameters, including: According to the plastic density difference ≤ ± 0.02g / cm 3 and the component ratio difference is ≤±3% and a plurality of candidate groups of cracking process parameters are obtained by preliminary screening from a historical process parameter library; The difference value δ is calculated according to the following formula. Only numerical values ​​are taken during the calculation. The three groups of historical parameters with the smallest difference value δ are taken, and then weighted average is performed to generate the first cracking process parameters; wherein, the difference value ,in is the current moisture content, unit: % is the historical moisture content, unit: % is the current feed amount, unit Kg; is the historical feed amount, unit Kg; The temperature curve and time parameters dynamically calculated according to the thermodynamic parameters are used to replace the temperature curve and time parameters in the first cracking process parameters to obtain the optimal cracking process parameters.

[0033] The temperature curve and time parameters are dynamically calculated based on thermodynamic parameters, including: Based on the cracking starting temperature Tonset, set the end temperature of the initial heating stage: initial end temperature = Tonset -20°C; The temperature of the main reaction zone is set at the maximum weight loss rate temperature Tmax: main reaction temperature = Tmax ± 10°C; Set the final holding temperature according to the predicted carbon residue rate Char: if the predicted carbon residue rate Char is greater than 8%, the final holding temperature = Tmax + 30°C; otherwise, the final holding temperature = Tmax + 10°C; Based on the difference between the melting temperature Tm and the cracking onset temperature Tonset, the homogenization time of the material is calculated: Homogenization time = (Tonset - Tm) × 0.5, unit: min; Main reaction time T = W × 2.5; where the unit of main reaction time T is min, W is the width of the mass loss interval, and only the numerical value is used during calculation. W is specifically the width of the 90% mass loss interval in the thermogravimetric analysis test procedure.

[0034] Specifically, the present invention guides the current cracking process by detecting the parameters of the original plastic and matching the processing parameters with the same parameters in the processing system based on the parameters. By detecting the parameters of the original plastic and matching the processing technology with the same parameters in the past, the basic cracking process parameter group can be screened out and then combined with the thermodynamic parameters and the difference value calculated according to the moisture content and feed amount to further determine the optimal cracking process parameters, wherein the cracking temperature curve and time parameters are dynamically generated completely by the thermodynamic parameters, avoiding historical experience deviations and solving the defect of the traditional process relying on fixed temperature. Therefore, the temperature and time parameters are completely generated by thermal analysis data and are not affected by historical parameters. Of course, the time parameter can also be generated according to the weighted historical value and thermodynamic parameter. In traditional cracking processing, it is often necessary to adjust parameters multiple times to find the optimal cracking conditions. This method reduces the trial and error process through experience matching and directly adopts verified process parameters, thereby significantly improving the cracking efficiency. The process parameters based on past experience are usually optimized to ensure that the cracking process is carried out under the lowest energy consumption. Accurate process parameters can avoid the equipment from operating under unsuitable conditions, thereby reducing equipment wear and maintenance costs. This method relies on the detection of original plastic parameters and the analysis of past processing data. It is a data-driven decision-making method. By accumulating a large amount of processing data, the system can continuously optimize the matching algorithm and improve the accuracy of decision-making. By detecting and matching process parameters, the system can flexibly handle waste plastics of different compositions and states, further improving the accuracy of the waste polyolefin plastic cracking and recovery system based on multi-dimensional data monitoring.

[0035] Specifically, the detection unit includes: The parameter detection subunit is connected to the cracking unit and is used to insert the temperature measuring end of the thermometer into the center of the material to measure the cracking temperature, and to measure the cracking pressure of the gas phase space above the cracking reactor through the pressure sensitive element.

[0036] Specifically, the detection unit also includes: The product detection subunit is connected to the cracking unit and is used to detect the long-chain alkane content and benzene concentration of the cracking gas by gas chromatography, and to measure the viscosity and olefin ratio of the cracking liquid by Brookfield viscometer, and to obtain the carbon deposition rate by sampling and detecting the cracking solids on the inner wall of the cracking reactor.

[0037] Specifically, the present invention adjusts the parameters of the cracking process by detecting products associated with the cracking process parameters. During the cracking process, the composition and yield of the products will be affected by multiple parameters such as cracking temperature, pressure, and feed rate. By detecting the products, the system can understand the effect of the current cracking process in real time and dynamically adjust the cracking parameters according to the actual state of the products. Over-cracking may result in excessive low-value by-products in the products, while under-cracking will result in incomplete conversion of the raw materials. By detecting the products and adjusting the cracking parameters, these two situations can be effectively avoided, ensuring that the cracking process is always in the optimal state. By detecting the products, the system can accurately adjust the cracking parameters according to the requirements of the target product, thereby improving the quality and purity of the product. Some impurities and by-products may be generated during the cracking process. These substances will affect the quality and subsequent application of the product. By real-time monitoring of the products and adjusting the cracking parameters, the generation of these impurities and by-products can be reduced, thereby improving the overall quality of the product. By accurately controlling the cracking process, it can ensure that the raw materials are converted into the target products to the maximum extent, reduce the waste of raw materials caused by incomplete cracking or inappropriate parameters, and further improve the accuracy of the waste polyolefin plastic cracking and recovery system based on multi-dimensional data monitoring.

[0038] See also Figure 2 As shown in FIG, it is a structural block diagram of a control unit according to an embodiment of the present invention, and the control unit includes: The temperature subunit is connected to the cracking unit and the detection unit respectively, and is used to determine whether to increase the temperature based on the content of long-chain alkanes, and to determine whether to decrease the temperature based on the concentration of benzene series.

[0039] It can be understood that if the long-chain alkane content is greater than or equal to the preset long-chain alkane content, it is determined that the temperature of the cracking reactor is increased; It can be understood that if the BTEX concentration is greater than or equal to the preset BTEX concentration, it is determined that the reactor temperature is increased or decreased; In a specific embodiment, the preset long-chain alkane content is set to 5%. If the long-chain alkane content is 6.2% and is greater than the preset long-chain alkane content, it is determined that the temperature of the cracking reactor is increased; In a specific embodiment, the preset BTEX concentration is set to 1%. If the BTEX concentration is 1.4% and is greater than the preset BTEX concentration, it is determined that the reactor temperature should be increased or decreased. Optionally, the preset long-chain alkane content is 5%, and the preset benzene series concentration is 1%.

[0040] See also Figure 3 As shown in FIG. 1 , which is a logic diagram for determining whether to open the exhaust valve according to an embodiment of the present invention, the control unit further includes: The pressure subunit is connected to the cracking unit and the detection unit respectively, and is used to compare the cracking pressure with the preset pressure and determine whether to open the exhaust valve based on the comparison result. The preset pressure is positively correlated with the feed amount of the plastic raw material.

[0041] If the cracking pressure is greater than or equal to the preset pressure, the exhaust valve is opened; If the cracking pressure is lower than the preset pressure, the exhaust valve is closed; In a specific embodiment, the preset pressure is set to 0.4 MPa, and if the cracking pressure is 0.6 MPa and is greater than the preset pressure, it is determined that the exhaust valve is opened; If the cracking pressure is 0.3 MPa less than the preset pressure, the exhaust valve is determined to be closed; It is understandable that the greater the feed amount of plastic raw material, the greater the amount of gas generated per unit time, so the preset pressure is positively correlated with the feed amount of plastic raw material.

[0042] See also Figure 4 As shown, it is a logic diagram for determining whether the cracking reaction is completed according to an embodiment of the present invention. The control unit also includes: The time subunit is connected to the cracking unit and the detection unit respectively, and is used to compare the carbon deposition rate with the preset carbon deposition rate, and determine whether the cracking reaction is completed based on the comparison result. The preset carbon deposition rate is positively correlated with the feed amount of the plastic raw material.

[0043] If the carbon deposition rate is greater than or equal to the preset carbon deposition rate, the cracking reaction is determined to be complete; If the carbon deposition rate is less than the preset carbon deposition rate, it is determined that the cracking reaction is not completed; In a specific embodiment, the preset carbon deposition rate is 5%. If the carbon deposition rate is 8% and is greater than the preset carbon deposition rate, it is determined that the cracking reaction is complete. If the carbon deposition rate is 2% less than the preset carbon deposition rate, it is determined that the cracking reaction is not completed; It is understandable that the more the plastic raw material is fed, the greater the amount of carbon deposits produced, so the preset carbon deposition rate is positively correlated with the plastic raw material feed amount.

[0044] Furthermore, the temperature subunit is also used to: receiving the reactor weight loss rate data detected in real time by the detection unit and the reactor weight loss rate curve predicted by the thermal analysis subunit through thermogravimetric analysis; Compare the deviation ΔW between the real-time detected reactor weight loss rate and the predicted reactor weight loss rate, and dynamically adjust the main reaction temperature. Only numerical values ​​are used during calculation, including: If ΔW > +5%, temperature rise compensation: ; If ΔW < -5%, temperature compensation: ; in, is the adjusted main reaction temperature, unit: °C; is the main reaction temperature before adjustment, unit is ℃.

[0045] Specifically, the control unit also includes: The stirring subunit is connected to the cracking unit and the detection unit respectively, and is used to determine whether to reduce the stirring rate based on the olefin ratio, and to determine whether to increase the stirring rate based on the viscosity.

[0046] It can be understood that if the olefin ratio is greater than or equal to the preset olefin ratio, it is determined to reduce the stirring rate.

[0047] It can be understood that if the viscosity is greater than or equal to the preset viscosity, it is determined that the stirring rate is increased.

[0048] In a specific embodiment, the preset olefin ratio is set to 60%. If the olefin ratio is 72% and is greater than the preset olefin ratio, it is determined to reduce the stirring rate. In a specific embodiment, the preset viscosity is set to 50 cP, and if the viscosity is 58 cP, which is greater than the preset viscosity, it is determined that the stirring rate should be increased; Optionally, the preset olefin ratio is 60% and the preset viscosity is 50 cP.

[0049] Specifically, the present invention improves the timeliness of monitoring the cracking process by adjusting the cracking-related parameters of the cracking reactor. By adjusting the relevant parameters of the cracking reactor, the system can more quickly obtain real-time data from the cracking process. This real-time monitoring capability enables the system to promptly detect anomalies or deviations during the cracking process and make rapid adjustments. Traditional cracking and recovery systems may be unable to promptly capture key changes in the cracking process due to delays in monitoring equipment or slow data processing speeds. The present invention reduces this lag by optimizing parameter adjustment, ensuring that the system can quickly respond to dynamic changes in the cracking process. By optimizing and adjusting the parameters of the cracking reactor, the system can more accurately control the cracking process. Multidimensional data monitoring combined with parameter adjustment can reduce errors and uncertainties caused by changes in equipment, raw materials, or operating conditions. Traditional cracking and recovery systems may have low cracking efficiency due to unreasonable parameter settings. The present invention avoids ineffective operations and improves cracking efficiency through real-time monitoring and parameter adjustment. The composition and state of waste polyolefin plastics may vary greatly. By adjusting the parameters of the cracking reactor, the system can flexibly process different types of plastics, improving the system's versatility and adaptability, and further enhancing the accuracy of the waste polyolefin plastic cracking and recovery system based on multidimensional data monitoring.

[0050] The scope of this application is defined by the appended claims rather than the foregoing description and is therefore intended to encompass within this application all changes that come within the meaning and range of equivalents of the claims. Any reference signs in the claims should not be construed as limiting the claims to which they relate. In addition, it is clear that the word "comprising" does not exclude other units or steps, and the singular does not exclude the plural. Multiple units or devices stated in a device claim may also be implemented by one unit or device through software or hardware. Words such as "first" and "second" are only used to distinguish the description and do not indicate any particular order, nor should they be understood as indicating or implying relative importance.

[0051] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any person skilled in the art may easily propose variations or substitutions within the technical scope disclosed in the present application, and such variations or substitutions shall be encompassed within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be subject to the scope of protection of the claims, and the above embodiments shall be regarded as exemplary and non-limiting.

Claims

1. A waste polyolefin plastic cracking and recovery system based on multi-dimensional data monitoring, characterized in that: include: A pre-treatment unit, which is used to crush, clean and dry waste polyolefin plastics to generate plastic raw materials; a collection unit connected to the pretreatment unit, for collecting the moisture content, plastic density, and composition ratio of each monomer plastic of the plastic raw material, and performing differential scanning calorimetry and thermogravimetric analysis on representative plastic raw material samples to obtain thermodynamic parameters including melting temperature, cracking onset temperature, maximum weight loss rate temperature, and predicted carbon residue rate; A feeding unit connected to the collection unit is used to build a plastic feeding model based on the plastic density and the component ratio, and to control the feeding amount based on the plastic feeding model and the moisture content, and to associate the thermodynamic parameters in real time with the feeding batch corresponding to the sampling period; a cracking unit, connected to the collection unit and the feeding unit, respectively, for matching cracking process parameters according to the plastic feeding model, the moisture content, the feeding amount, and the thermodynamic parameters corresponding to the feeding batch, and adjusting the cracking reactor based on the cracking process parameters; a detection unit connected to the cracking unit, for detecting cracking process parameters of the cracking reactor and cracking products, wherein the cracking process parameters include cracking temperature, cracking pressure and cracking time, and the cracking products include cracking gas, cracking liquid and cracking solid; A control unit is connected to the cracking unit and the detection unit, respectively, for adjusting the cracking process parameters based on the cracking product and determining whether the cracking reaction is completed, and when it is determined that the cracking reaction is completed, recording the cracking process parameters and adjusting the cracking process parameters in combination with the plastic feeding model.

2. The waste polyolefin plastic cracking and recovery system based on multidimensional data monitoring according to claim 1 is characterized in that: The acquisition unit includes: a component subunit connected to the pretreatment unit, for determining the component ratio of each monomer plastic of the waste polyolefin plastic based on image analysis and infrared spectroscopy; a measuring subunit, connected to the pre-processing unit, for measuring the density of the plastic based on a density gradient column method and detecting the moisture content by a drying method; The thermal analysis subunit includes a conveyor belt dynamic sampling device, a micro differential scanning calorimeter and a thermogravimetric analyzer combination device. It obtains the dried plastic raw material flow through the pneumatic sampling valve installed in the middle of the conveyor belt in the conveyor belt dynamic sampling device, generates a representative sample through an automatic reduction device, and conveys it to the micro differential scanning calorimeter and thermogravimetric analyzer combination device for thermal analysis. Specifically, under a nitrogen atmosphere, a differential scanning calorimetry test procedure is performed: the plastic sample is heated from room temperature to 300°C at a constant heating rate of 20°C / minute, and its melting temperature is determined by monitoring the sample absorption / release of heat changes; and a thermogravimetric analysis test procedure is performed: the temperature is increased to 600°C at 30°C / minute to obtain the cracking starting temperature, the maximum weight loss rate temperature, and the predicted residual carbon rate.

3. The waste polyolefin plastic cracking and recovery system based on multidimensional data monitoring according to claim 2 is characterized in that: The feeding unit comprises: A modeling subunit, connected to the acquisition unit, for calculating the weight ratio of each monomer plastic according to the plastic density and the component ratio to construct the plastic feeding model; an execution subunit, connected to the acquisition unit and the modeling subunit, respectively, for comparing the moisture content with a preset moisture content, determining whether to start feeding according to the comparison result, and regulating the feed amount based on the weight ratio when it is determined that feeding is started; The preset moisture content is positively correlated with the weight ratio of the polar plastic.

4. The waste polyolefin plastic cracking and recovery system based on multidimensional data monitoring according to claim 3 is characterized in that: The cracking unit comprises: a process subunit, connected to the acquisition unit, the feeding unit, and the thermal analysis subunit, respectively, for selecting a plurality of the cracking process parameters of the same plastic density and composition according to the plastic feeding model, calculating a difference value according to the moisture content and the feed amount, and determining optimal cracking process parameters according to the difference value and the thermodynamic parameters; wherein the optimal cracking process parameters include: a temperature curve and time parameters, a reaction pressure setting value, a stirring rate, and a catalyst dosage; wherein the temperature curve and time parameters are dynamically calculated based on the thermodynamic parameters; The regulating subunit is connected to the process subunit and is used to regulate the working parameters of the cracking reactor based on the optimal cracking process parameters.

5. The waste polyolefin plastic cracking and recovery system based on multidimensional data monitoring according to claim 4 is characterized in that: in, The process subunit selects several cracking process parameters of the same plastic density and the same composition according to the plastic feed model, calculates and generates difference values ​​according to the moisture content and the feed amount, and determines the optimal cracking process parameters according to the difference values ​​and the thermodynamic parameters, including: According to the plastic density difference ≤ ± 0.02g / cm 3 and the component ratio difference is ≤±3% and a plurality of candidate groups of cracking process parameters are obtained by preliminary screening from a historical process parameter library; The difference value δ is calculated according to the following formula. Only numerical values ​​are taken during the calculation. The three groups of historical parameters with the smallest difference value δ are taken, and then weighted average is performed to generate the first cracking process parameters; wherein, the difference value ,in is the current moisture content, unit: % is the historical moisture content, unit: % is the current feed amount, unit Kg; is the historical feed amount, unit Kg; The temperature curve and time parameters dynamically calculated according to the thermodynamic parameters are used to replace the temperature curve and time parameters in the first cracking process parameters to obtain the optimal cracking process parameters.

6. The waste polyolefin plastic cracking and recovery system based on multidimensional data monitoring according to claim 5 is characterized in that: in, The temperature curve and time parameters are dynamically calculated based on thermodynamic parameters, including: Based on the cracking starting temperature Tonset, set the end temperature of the initial heating stage: initial end temperature = Tonset -20°C; The temperature of the main reaction zone is set at the maximum weight loss rate temperature Tmax: main reaction temperature = Tmax ± 10°C; Set the final holding temperature according to the predicted carbon residue rate Char: if the predicted carbon residue rate Char is greater than 8%, the final holding temperature = Tmax + 30°C; otherwise, the final holding temperature = Tmax + 10°C; Based on the difference between the melting temperature Tm and the cracking onset temperature Tonset, the homogenization time of the material is calculated: Homogenization time = (Tonset - Tm) × 0.5, unit: min; Main reaction time T = W × 2.5; where the unit of main reaction time T is min, W is the width of the mass loss interval, and only the numerical value is used during calculation. W is specifically the width of the 90% mass loss interval in the thermogravimetric analysis test procedure.

7. The waste polyolefin plastic cracking and recovery system based on multidimensional data monitoring according to claim 4 is characterized in that: The detection unit comprises: The parameter detection subunit is connected to the cracking unit and is used to insert the temperature measuring end of the thermometer into the center of the material to measure the cracking temperature, and to measure the cracking pressure in the gas phase space above the cracking reactor through a pressure sensitive element.

8. The waste polyolefin plastic cracking and recovery system based on multidimensional data monitoring according to claim 7 is characterized in that: The detection unit also includes: The product detection subunit is connected to the cracking unit and is used to detect the long-chain alkane content and benzene concentration of the cracked gas by gas chromatography, measure the viscosity and olefin ratio of the cracked liquid by Brookfield viscometer, and obtain the carbon deposition rate by sampling and detecting the cracked solid on the inner wall of the cracking reactor.

9. The waste polyolefin plastic cracking and recovery system based on multi-dimensional data monitoring according to claim 8, characterized in that: The control unit comprises: a temperature subunit, connected to the cracking unit and the detection unit, respectively, for determining whether to increase the temperature based on the long-chain alkane content, and determining whether to decrease the temperature based on the benzene series concentration; a pressure subunit, connected to the cracking unit and the detection unit, respectively, for comparing the cracking pressure with a preset pressure and determining whether to open the exhaust valve based on the comparison result, wherein the preset pressure is positively correlated with the feed amount of the plastic raw material; a time subunit, connected to the cracking unit and the detection unit, respectively, for comparing the carbon deposition rate with a preset carbon deposition rate and determining whether the cracking reaction is completed based on the comparison result, wherein the preset carbon deposition rate is positively correlated with the feed amount of the plastic raw material; The stirring sub-unit is connected to the cracking unit and the detection unit respectively, and is used to determine whether to reduce the stirring rate based on the olefin ratio, and to determine whether to increase the stirring rate based on the viscosity.

10. The waste polyolefin plastic cracking and recovery system based on multi-dimensional data monitoring according to claim 9, characterized in that: The temperature subunit is further used for: receiving the reactor weight loss rate data detected in real time by the detection unit and the reactor weight loss rate curve predicted by the thermal analysis subunit through thermogravimetric analysis; Compare the deviation ΔW between the real-time detected reactor weight loss rate and the predicted reactor weight loss rate, and dynamically adjust the main reaction temperature. Only numerical values ​​are used during calculation, including: If ΔW > +5%, temperature rise compensation: ; If ΔW < -5%, temperature compensation: ; in, is the adjusted main reaction temperature, unit: °C; is the main reaction temperature before adjustment, unit is ℃.

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