A waste polyolefin plastic cracking and recycling system based on multidimensional data monitoring

Abstract

The application relates to the technical field of plastic cracking, in particular to a waste polyolefin plastic cracking and recycling system based on multidimensional data monitoring, which comprises a pretreatment unit used for crushing, cleaning and drying treatment of waste polyolefin plastics to generate plastic raw materials; a collection unit used for collecting the moisture content of the plastic raw materials, 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; a feeding unit used for constructing a plastic feeding model and regulating the feeding amount; a cracking unit used for matching cracking process parameters and adjusting a cracking reaction kettle; a detection unit used for detecting cracking process parameters and cracking products; and a control unit used for judging whether the cracking reaction is completed and adjusting the cracking process parameters; the application effectively monitors the plastic cracking process and further improves the accuracy of the existing waste polyolefin plastic cracking and recycling system.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of plastic cracking, in particular to a waste polyolefin plastic cracking and recycling system based on multidimensional data monitoring. BACKGROUND

[0002] Waste polyolefin plastics (such as polyethylene and polypropylene) are common waste plastics, which are difficult to naturally degrade and can cause serious pollution to soil, water and ecosystems if they are long-term accumulated. The traditional landfill and incineration treatment methods not only occupy a large amount of land resources, but also produce harmful gas and greenhouse gas emissions. With the global emphasis on sustainable development, how to effectively recycle and reuse waste plastics has become a problem to be solved. Cracking and recycling technology can convert waste plastics into high-value fuels or chemical raw materials, reduce the dependence on virgin resources, and realize the recycling of resources. With the rapid development of sensor technology, automation control technology and data analysis technology, a multidimensional data monitoring system can monitor the temperature, pressure, gas composition, liquid product composition and other multidimensional data in the cracking process in real time. These data can be used to optimize the cracking conditions, improve the cracking efficiency and product quality.

[0003] Chinese Patent Application Publication No. CN117417762A discloses an industrial continuous precise regulation and control of mixed waste plastic van-type cracking method. The invention provides an industrial continuous precise regulation and control of mixed waste plastic van-type cracking method. The process is realized by a plurality of van-type cracking reaction kettles constituting the total cracking system, which includes the following steps: setting the cracking process conditions in each van-type cracking reaction kettle according to the physicochemical properties of mixed waste plastics; mixed waste plastics are quantitatively transported into the van-type cracking reaction kettle through the feeding system according to the component proportion in the mixed waste plastics; the proportion of each monomer plastic in the mixed waste plastics such as PP, PE and PVC is preliminarily estimated through the feeding system, and the cracking process is finely regulated and controlled by the corresponding feeding amount and cracking process conditions of each monomer plastic in the mixed waste plastics in the system, so as to realize the regulation and control of the mixed waste plastic cracking products, greatly improving the quality of the mixed waste plastic cracking products and improving their economic added value.

[0004] However, the above method has the following problems: the cracking parameters cannot be adjusted by detailed analysis of the cracking products in the reaction process. SUMMARY

[0005] Therefore, the application provides a waste polyolefin plastic cracking and recycling system based on multidimensional data monitoring to overcome the problem that the cracking parameters cannot be adjusted by detailed analysis of the cracking products in the reaction process in the prior art.

[0006] To achieve the above purpose, the application provides a waste polyolefin plastic cracking and recycling system based on multidimensional data monitoring, which comprises:

[0007] a pretreatment unit configured to crush, clean and dry the waste polyolefin plastics to generate plastic raw materials;

[0008] a collection unit connected to the pretreatment unit and configured to collect water content, plastic density and component proportion of each monomer plastic of the plastic raw materials, and perform differential scanning calorimetry and thermogravimetric analysis on a representative sample of the plastic raw materials to obtain thermodynamic parameters including melting temperature, cracking initiation temperature, maximum weight loss rate temperature and predicted residual carbon rate;

[0009] a feeding unit connected to the collection unit and configured to construct a plastic feeding model based on the plastic density and the component proportion, regulate the amount of feedstock based on the plastic feeding model and the water content, and associate the thermodynamic parameters in real time to the feedstock batch corresponding to the sampling period;

[0010] a cracking unit connected to the collection unit and the feeding unit respectively, and configured to match cracking process parameters according to the plastic feeding model, the water content, the amount of feedstock and the thermodynamic parameters corresponding to the feedstock batch, and adjust the cracking reactor based on the cracking process parameters;

[0011] a detection unit connected to the cracking unit and configured to detect cracking process parameters of the cracking reactor, and detect 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;

[0012] a control unit connected to the cracking unit and the detection unit respectively, and configured to adjust the cracking process parameters based on the cracking products and determine whether the cracking reaction is completed, and in the state of determining that the cracking reaction is completed, record the cracking process parameters to adjust the cracking process parameters in combination with the plastic feeding model.

[0013] Further, the collection unit comprises:

[0014] a component subunit connected to the pretreatment unit and configured to determine the component proportion of each monomer plastic of the waste polyolefin plastics based on image analysis and infrared spectrum;

[0015] a measurement subunit connected to the pretreatment unit and configured to measure the plastic density based on density gradient column method, and detect the water content by drying method;

[0016] The thermal analysis subunit comprises a conveyor belt dynamic sampling device, a micro-differential scanning calorimeter (DSC) and a thermal gravimetric analyzer (TGA) combined device. The dry plastic raw material flow is obtained by the pneumatic sampling valve installed in the middle of the conveyor belt of the conveyor belt dynamic sampling device, and the representative sample is transported to the micro-differential scanning calorimeter (DSC) and thermal gravimetric analyzer (TGA) combined device for thermal analysis. Specifically, under the nitrogen atmosphere, the differential scanning calorimetry test program is executed: the plastic sample is heated from room temperature to 300℃ at a constant temperature rate of 20℃ / min, and the melting temperature is determined by monitoring the heat absorption / heat release change of the sample; and the thermal gravimetric analysis test program is executed: heating to 600℃ at a rate of 30℃ / min to obtain the cracking initiation temperature, the maximum weight loss rate temperature, and the predicted residual carbon rate.

[0017] Further, the feeding unit comprises:

[0018] The modeling subunit is connected with the collecting unit, and is used to calculate the weight ratio of each monomer plastic according to the plastic density and the component proportion to construct the plastic feeding model;

[0019] The execution subunit is connected with the collecting unit and the modeling subunit respectively, and is used to compare the water content with the preset water content, determine whether to start feeding according to the comparison result, and control the feeding amount based on the weight ratio in the state of determining to start feeding.

[0020] The preset water content is positively correlated with the weight ratio of the polar plastic.

[0021] Further, the cracking unit comprises:

[0022] The process subunit is connected with the collecting unit, the feeding unit and the thermal analysis subunit respectively, and is used to select a plurality of cracking process parameters of the same plastic density and the same component according to the plastic feeding model, calculate a difference value according to the water content and the feeding amount, and determine the optimal cracking process parameter according to the difference value and the thermodynamic parameter; wherein the optimal cracking process parameter comprises: temperature curve and time parameter, reaction pressure set value, stirring rate and catalyst dosage; wherein the temperature curve and time parameter are dynamically calculated based on the thermodynamic parameter.

[0023] The adjustment subunit is connected with the process subunit, and is used to adjust the working parameter of the cracking reactor based on the optimal cracking process parameter.

[0024] Further, wherein 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 a difference value according to the water content and the feed amount, and determines the optimal cracking process parameters according to the difference value and the thermodynamic parameters, including:

[0025] According to the plastic density difference ≤ ± 0.02 g / cm 3 And the composition ratio difference ≤ ± 3% from the historical process parameter library, get several groups of candidate cracking process parameters;

[0026] According to the following formula to calculate the difference value δ, only take the numerical value when calculating, take the minimum difference value δ of 3 groups of historical parameters, and then perform weighted average to generate the first cracking process parameters; wherein the difference value , wherein The current water content is %, unit %; The historical water content is %, unit %; The current feed amount is Kg, unit Kg; The historical feed amount is Kg, unit Kg;

[0027] According to the temperature curve and time parameters dynamically calculated according to the thermodynamic parameters, replace the temperature curve and time parameters in the first cracking process parameters to obtain the optimal cracking process parameters.

[0028] Further, wherein the temperature curve and time parameters are dynamically calculated based on thermodynamic parameters, including:

[0029] Take the cracking starting temperature Tonset as the benchmark, set the initial temperature rise segment end temperature: initial end temperature = Tonset - 20 °C;

[0030] Take the maximum weight loss rate temperature Tmax as the main reaction zone temperature set point: main reaction temperature = Tmax ± 10 °C;

[0031] According to the predicted residual carbon rate Char, set the final holding temperature: if the predicted residual carbon rate Char > 8%, the final holding temperature = Tmax + 30 °C, otherwise, the final holding temperature = Tmax + 10 °C;

[0032] Based on the difference between the melting temperature Tm and the cracking starting temperature Tonset, the material homogenization time is calculated: homogenization time = (Tonset - Tm) × 0.5, unit: min;

[0033] Main reaction time T = W × 2.5; wherein the unit of main reaction time T is min, W is the mass loss interval width, only take the numerical value when calculating, W is the 90% mass loss interval width in the thermogravimetric analysis test program.

[0034] Further, the detection unit comprises:

[0035] a parameter detection subunit connected with the cracking unit, for inserting a thermometer probe into the center of the material to measure the cracking temperature, and for measuring the cracking pressure in the gas phase space above the cracking reactor by a pressure-sensitive element.

[0036] Further, the detection unit further comprises:

[0037] a product detection subunit connected with the cracking unit, for detecting the long-chain alkane content and benzene series concentration of the cracking gas by gas chromatography, and for measuring the viscosity and olefin proportion of the cracking liquid by a Brookfield viscometer, and for obtaining the coke deposition rate by sampling the cracking solid on the inner wall of the cracking reactor.

[0038] Further, the control unit comprises:

[0039] a temperature subunit connected with 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;

[0040] a pressure subunit connected with 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 according to the comparison result, the preset pressure being positively correlated with the feed amount of the plastic raw material;

[0041] a time subunit connected with the cracking unit and the detection unit respectively, for comparing the coke deposition rate with a preset coke deposition rate, and determining whether the cracking reaction is completed according to the comparison result, the preset coke deposition rate being positively correlated with the feed amount of the plastic raw material;

[0042] a stirring subunit connected with the cracking unit and the detection unit respectively, for determining whether to decrease the stirring rate based on the olefin proportion, and determining whether to increase the stirring rate based on the viscosity.

[0043] Further, the temperature subunit is further used for:

[0044] receiving the reactor weight loss rate data detected by the detection unit in real time and the reactor weight loss rate curve predicted by the thermal analysis subunit through thermal gravimetric analysis;

[0045] comparing the deviation AW between the reactor weight loss rate detected in real time and the predicted reactor weight loss rate, and dynamically adjusting the main reaction temperature, the calculation being performed only on the numerical value, including:

[0046] if AW > +5%, increasing the temperature to compensate: ;

[0047] If ΔW < -5%, cooling compensation: ;

[0048] Wherein, is the adjusted main reaction temperature, unit ℃; is the unadjusted main reaction temperature, unit ℃.

[0049] Compared with the prior art, the beneficial effects of the present application are that the present application constructs a plastic feed model by collecting the parameters of the original plastic, adjusts the feed amount in combination with the moisture content and the weight ratio of each monomer plastic, the properties of the original plastic have an important influence on the cracking process and product distribution in the plastic cracking and recycling process, by collecting these parameters, the characteristics of the input material can be better understood, the moisture in the plastic will affect the cracking process, too much moisture may cause the cracking temperature to be unstable, increase energy consumption, and may affect the quality and yield 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 plastic is usually mixed by a plurality of monomer plastics, the cracking characteristics of different monomer plastics are different, therefore the feed amount needs to be adjusted according to the weight ratio of each monomer plastic, through multidimensional data monitoring, in combination with the feed model and parameter adjustment, fine management of the cracking process can be realized, and the accuracy of the waste polyolefin plastic cracking and recycling system based on multidimensional data monitoring is effectively improved.

[0050] Further, the present application detects the parameters of the original plastic, matches the same processing parameters as the past parameters based on each parameter in the processing system, guides the cracking process this time, detects the parameters of the original plastic, matches the processing parameters with the same parameters in the past, selects the basic cracking process parameter group, and then combines the thermodynamic parameters and the difference value calculated according to the water content and the feed amount to further determine the optimal cracking process parameters, wherein the cracking temperature curve and the time parameter are completely generated by the thermodynamic parameters, avoiding the deviation of historical experience, solving the defect of relying on fixed temperature in traditional process, so the temperature and time parameters are completely generated by thermal analysis data, and are not affected by historical parameters. In the traditional cracking process, it is often necessary to adjust the parameters several times to find the best cracking conditions, and this method reduces the trial and error process by matching experience, directly uses the 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 at the lowest energy consumption, and accurate process parameters can avoid the operation of equipment under unsuitable conditions, thereby reducing the wear and maintenance cost of equipment. This method relies on the detection of original plastic parameters and the analysis of past processing data, and is a data-driven decision-making method. By accumulating a large amount of processing data, the system can continuously optimize the matching algorithm to improve the accuracy of decision-making. By detecting and matching process parameters, the system can flexibly handle waste plastics of different components and states, further improving the accuracy of the waste polyolefin plastic cracking and recycling system based on multi-dimensional data monitoring.

[0051] Further, the present application detects and adjusts the parameters of the cracking process by detecting the products associated with the cracking process parameters. In the cracking process, the composition and yield of the products are affected by multiple parameters such as cracking temperature, pressure, and feed speed. 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 too many low-value by-products in the products, while under-cracking may result in incomplete conversion of raw materials. By detecting the products and adjusting the cracking parameters, these two situations can be effectively avoided to ensure that the cracking process is always in the best state. By detecting the products, the system can accurately adjust the cracking parameters according to the requirements of the target product to improve the quality and purity of the product. Some impurities and by-products may be produced during the cracking process, which will affect the quality of the product and subsequent application. By real-time monitoring of the products and adjusting the cracking parameters, the generation of these impurities and by-products can be reduced to improve the overall quality of the product. By precisely controlling the cracking process, the raw materials can be maximally converted into target products, reducing waste caused by incomplete cracking or improper parameters, and further improving the accuracy of the waste polyolefin plastic cracking and recycling system based on multi-dimensional data monitoring.

[0052] Furthermore, this invention improves the timeliness of monitoring the pyrolysis process by adjusting the pyrolysis-related parameters of the pyrolysis reactor. By adjusting the relevant parameters of the pyrolysis reactor, the system can acquire real-time data during the pyrolysis process more quickly. This real-time monitoring capability enables the system to promptly detect anomalies or deviations during the pyrolysis process and make rapid adjustments. Traditional pyrolysis recovery systems may fail to capture key changes in the pyrolysis process in a timely manner due to delays in monitoring equipment or slow data processing speeds. This invention reduces this lag by optimizing parameter adjustments, ensuring that the system can quickly respond to dynamic changes during the pyrolysis process. Through optimized adjustment of the pyrolysis reactor parameters, the system can more accurately control the pyrolysis process. Multidimensional data monitoring combined with parameter adjustment can reduce errors and uncertainties caused by changes in equipment, raw materials, or operating conditions. Traditional pyrolysis recovery systems may suffer from low pyrolysis efficiency due to unreasonable parameter settings. This invention avoids ineffective operations and improves pyrolysis 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 pyrolysis reactor, the system can flexibly handle different types of plastics, improving the system's versatility and adaptability, and further enhancing the accuracy of the waste polyolefin plastic pyrolysis recovery system based on multidimensional data monitoring. Attached Figure Description

[0053] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0054] Figure 1 This is a structural block diagram of the waste polyolefin plastic pyrolysis and recycling system based on multidimensional data monitoring according to the present invention;

[0055] Figure 2 This is a structural block diagram of the control unit in an embodiment of the present invention;

[0056] Figure 3 This is a logic diagram for determining whether to open the exhaust valve according to an embodiment of the present invention;

[0057] Figure 4 This is a logic diagram for determining whether a pyrolysis reaction is complete in an embodiment of the present invention. Detailed Implementation

[0058] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the following will be combined with the drawings in the embodiments of the present application to make a clear and complete description of the technical solutions in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0059] It should be noted that the terms "first", "second" and the like in the description and claims of the present application and the above drawings are used to distinguish similar objects, and do not necessarily indicate a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units need not be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0060] Please refer to Figure 1 As shown in the structure block diagram of the waste polyolefin plastic cracking and recycling system based on multi-dimensional data monitoring, the embodiments of the present application provide a waste polyolefin plastic cracking and recycling system based on multi-dimensional data monitoring, comprising:

[0061] A pretreatment unit is used to crush, wash and dry the waste polyolefin plastic to generate plastic raw materials;

[0062] A collection unit is connected with the pretreatment unit, used to collect the moisture content, plastic density and component proportion of each monomer plastic of the plastic raw materials, and perform differential scanning calorimetry and thermogravimetric analysis on a representative plastic raw material sample to obtain thermodynamic parameters including melting temperature, cracking initiation temperature, maximum weight loss rate temperature and predicted residual carbon rate;

[0063] A feeding unit is connected with the collection unit, used to construct a plastic feeding model based on the plastic density and the component proportion, and to regulate the feeding amount based on the plastic feeding model and the moisture content, and to associate the thermodynamic parameters in real time to the feeding batch corresponding to the sampling period;

[0064] A cracking unit is connected with the collection unit and the feeding unit respectively, used to match 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 to adjust the cracking reaction kettle based on the cracking process parameters;

[0065] a detection unit connected with the cracking unit, for detecting cracking process parameters and cracking products, the cracking process parameters including cracking temperature, cracking pressure and cracking time, the cracking products including cracking gas, cracking liquid and cracking solid;

[0066] a control unit connected with the cracking unit and the detection unit, for adjusting the cracking process parameters based on the cracking products and determining whether the cracking reaction is completed, and in the state of determining that the cracking reaction is completed, recording the cracking process parameters to adjust the cracking process parameters in combination with a plastic feed model.

[0067] Specifically, the collection unit comprises:

[0068] a component subunit connected with the pretreatment unit, for determining the component proportion of each monomer plastic of the waste polyolefin plastic based on image analysis and infrared spectrum;

[0069] a measurement subunit connected with the pretreatment unit, for measuring the plastic density based on the density gradient column method, and detecting the moisture content by the drying method;

[0070] a thermal analysis subunit comprising a conveyor belt dynamic sampling device, a micro-differential scanning calorimeter (DSC) and a thermogravimetric analyzer (TGA) combined device, which obtains the dried plastic raw material flow through the pneumatic sampling valve installed in the middle of the conveyor belt of the conveyor belt dynamic sampling device, and generates a certain mass of representative sample through the automatic division device to the micro-differential scanning calorimeter (DSC) and the thermogravimetric analyzer (TGA) combined device for thermal analysis. Specifically, under the nitrogen atmosphere, the differential scanning calorimetry test program is executed: the plastic sample is heated from room temperature to 300℃ at a constant temperature of 20℃ / min, and the melting temperature is determined by monitoring the heat absorption / heat release change of the sample; and the thermal gravimetric analysis test program is executed: heating to 600℃ at a rate of 30℃ / min to obtain the cracking initiation temperature, the maximum weight loss rate temperature and the predicted residual carbon rate. It can be understood that the pretreatment unit first cleans the waste polyolefin plastic, uses a high-resolution digital camera or an industrial camera to take pictures from different angles, processes the images to remove noise, extracts features, uses a Fourier transform infrared spectrometer to compare the collected spectrum with the infrared spectrum of standard polyolefin plastic, identifies characteristic absorption peaks, and fuses the results of image analysis and infrared spectrum analysis. Image analysis provides preliminary classification and appearance feature information, and infrared spectrum analysis provides accurate chemical component proportion.

[0071] It can be understood that according to the density range of the plastic to be measured, two suitable liquids are selected, for the plastic with a density of 0.83-0.96 g / cm3, a liquid with a density less than 0.83 g / cm3 and a liquid with a density greater than 0.96 g / cm3 are selected, for example, two liquids are selected as follows: acetone (density 0.7899 g / cm3) and saturated brine (density 1.2 g / cm3) or water (density 1 g / cm3), of course, other two mutually soluble liquids can also be selected according to actual needs, the two liquids are mixed in a certain proportion, poured into the density gradient column, the liquid with smaller density is added slowly, the liquid mixing is avoided, a plurality of points with known density are marked on the density gradient column, the positions of these points can be determined by adding standard samples with known density, the dried plastic sample is gently placed in the density gradient column, the sample is prevented from colliding with the liquid violently, after the sample is stationary, the suspension position of the sample in the density gradient column is observed, the sample will be suspended in the liquid layer with the same density as the sample, according to the suspension position of the sample, the corresponding density value on the density gradient column is read, if the sample is suspended between two marked points, the density of the sample can be calculated by interpolation method.

[0072] Specifically, the feeding unit comprises:

[0073] The modeling subunit is connected with the acquisition unit, and is used to calculate the weight ratio of each monomer plastic according to the plastic density and the proportion of the composition to construct a plastic feeding model;

[0074] The execution subunit is connected with the acquisition unit and the modeling subunit respectively, and is used to compare the water content with the preset water content, determine whether to start feeding according to the comparison result, and based on the weight ratio, control the feeding amount in the state of determining to start feeding;

[0075] If the water content is greater than or equal to the preset water content, it is determined to close the feeding;

[0076] If the water content is less than the preset water content, it is determined to start feeding;

[0077] In a specific embodiment, the preset water content is set to 2%, if the water content is 4% which is greater than the preset water content, it is determined to close the feeding;

[0078] If the water content is 1.2% which is less than the preset water content, it is determined to start feeding;

[0079] The preset water content is positively correlated with the weight ratio of the polar plastic.

[0080] It can be understood that the polar plastic has strong water absorption, the greater the weight ratio of the polar plastic, the greater the water content, so the preset water content is positively correlated with the weight ratio of the polar plastic.

[0081] Optionally, the preset water content value range is 2% to 3%.

[0082] Specifically, the application constructs a plastic feed model by collecting parameters of raw plastics, adjusts the feed amount according to the water content and the weight ratio of each monomer plastic, and in the plastic cracking and recycling process, the properties of raw plastics 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 yield of the product. By monitoring the water content, the feed amount can be adjusted to ensure the stability and efficiency of the cracking process. Waste polyolefin plastics are usually mixed by a plurality of monomer plastics, and the cracking characteristics of different monomer plastics are different. Therefore, the feed amount needs to be adjusted according to the weight ratio of each monomer plastic. Through multidimensional data monitoring, combined with the feed model and parameter adjustment, fine management of the cracking process can be realized, and the accuracy of the waste polyolefin plastic cracking and recycling system based on multidimensional data monitoring is effectively improved.

[0083] Specifically, the cracking unit comprises:

[0084] A process subunit connected to the collection unit, the feed unit and the thermal analysis subunit, for selecting a plurality of cracking process parameters with the same plastic density and the same composition according to the plastic feed model, and calculating a difference value according to the water content and the feed amount, and determining the optimal cracking process parameters according to the difference value and the thermodynamic parameters;

[0085] The optimal cracking process parameters are a combination of core adjustable variables that can maximize the cracking efficiency, and the optimal cracking process parameters include: temperature curve and time parameters, reaction pressure set value, stirring rate and catalyst dosage; wherein the temperature curve and time parameters are dynamically calculated based on the thermal analysis parameters;

[0086] An adjustment subunit connected to the process subunit for adjusting the working parameters of the cracking reactor based on the optimal cracking process parameters.

[0087] The process subunit selects a plurality of cracking process parameters with the same plastic density and the same composition according to the plastic feed model, and calculates a difference value according to the water content and the feed amount, and determines the optimal cracking process parameters according to the difference value and the thermodynamic parameters, which comprises:

[0088] According to the plastic density difference ≤ ± 0.02 g / cm 3 And the composition ratio difference ≤ ± 3% from the historical process parameter library, a plurality of candidate cracking process parameters are obtained;

[0089] The difference value δ is calculated according to the following formula, only the numerical value is taken, the minimum difference value δ of three groups of historical parameters is taken, and then a weighted average is generated to generate the first cracking process parameter; wherein the difference value δ wherein is the current water content, unit %; is the historical water content, unit %; is the current feed amount, unit Kg; is the historical feed amount, unit Kg;

[0090] According to the temperature curve and time parameter dynamically calculated by the thermodynamic parameters, the temperature curve and time parameter in the first cracking process parameter are replaced to obtain the optimal cracking process parameter.

[0091] wherein the temperature curve and time parameter are dynamically calculated based on the thermodynamic parameters, and specifically include:

[0092] Taking the cracking starting temperature Tonset as the benchmark, the initial heating end temperature is set: initial end temperature = Tonset - 20°C;

[0093] Taking the maximum weight loss rate temperature Tmax as the main reaction zone temperature set point: main reaction temperature = Tmax ± 10°C;

[0094] According to the predicted residual carbon rate Char, the final holding temperature is set: if the predicted residual carbon rate Char > 8%, the final holding temperature = Tmax + 30°C, otherwise, the final holding temperature = Tmax + 10°C;

[0095] Based on the difference between the melting temperature Tm and the cracking starting temperature Tonset, the material homogenization time is calculated: homogenization time = (Tonset - Tm) × 0.5, unit: min;

[0096] Main reaction time T = W × 2.5; wherein the unit of main reaction time T is min, W is the mass loss interval width, only the numerical value is taken when calculating, and W is specifically the 90% mass loss interval width in the thermogravimetric analysis test program.

[0097] Specifically, the present application detects the parameters of the original plastic, matches the same processing parameters as the past parameters in the processing system based on each parameter, guides the cracking processing this time, and selects the basic cracking process parameter group by detecting the parameters of the original plastic and matching the same parameters of the past processing process. Then combined with the thermodynamic parameters and the difference value calculated according to the moisture content and the feed amount to further determine the optimal cracking process parameters, wherein the cracking temperature curve and the time parameter are completely generated by the thermodynamic parameters, avoiding the deviation of historical experience, solving the defect of the traditional process relying on fixed temperature, so the temperature and time parameters are completely generated by the thermal analysis data, and are not affected by the historical parameters. Of course, the time parameter can also be generated according to the historical value and the thermodynamic parameter weighted. In the traditional cracking process, it is often necessary to adjust the parameters several times to find the best cracking condition, and this method reduces the trial and error process by experience matching, directly uses the 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 at the lowest energy consumption, and accurate process parameters can avoid the operation of equipment under unsuitable conditions, thereby reducing the wear and maintenance cost of equipment. This method relies on the detection of original plastic parameters and the analysis of past processing data, and is a data-driven decision-making method. By accumulating a large amount of processing data, the system can continuously optimize the matching algorithm to improve the accuracy of decision-making. Through the detection and matching of process parameters, the system can flexibly process waste plastics of different components and states, further improving the accuracy of the waste polyolefin plastic cracking and recycling system based on multi-dimensional data monitoring.

[0098] Specifically, the detection unit comprises:

[0099] The parameter detection subunit is connected with the cracking unit, and is used for inserting the temperature measuring end of the thermometer into the center of the material to measure the cracking temperature, and measuring the cracking pressure of the gas phase space in the upper part of the cracking reactor through the pressure sensitive element.

[0100] Specifically, the detection unit further comprises:

[0101] The product detection subunit is connected with the cracking unit, and is used for detecting the long-chain alkane content and benzene series concentration of the cracking gas by gas chromatography, measuring the viscosity and olefin proportion of the cracking liquid by the Brookfield viscometer, and obtaining the carbon deposition rate by sampling the cracking solid on the inner wall of the cracking reactor.

[0102] Specifically, the present application adjusts the parameters of the cracking process by detecting the products associated with the cracking process parameters, which are affected by various parameters such as cracking temperature, pressure, feed rate, etc. By detecting the products, the system can understand 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 may result in incomplete conversion of 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 best 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 produced during the cracking process, which will affect the quality of the product and subsequent application. 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 precisely controlling the cracking process, the raw materials can be maximally converted into target products, reducing waste due to incomplete cracking or improper parameters, and further improving the accuracy of the waste polyolefin plastic cracking and recycling system based on multi-dimensional data monitoring.

[0103] Referring to Figure 2 As shown in the figure, it is a structural block diagram of the control unit of the embodiment of the present application, and the control unit comprises:

[0104] A temperature sub-unit 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.

[0105] 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 cracking reactor is heated up;

[0106] It can be understood that if the benzene series concentration is greater than or equal to the preset benzene series concentration, it is determined that the reactor is heated up and cooled down;

[0107] In a specific embodiment, the preset long-chain alkane content is set to 5%, and if the long-chain alkane content is 6.2% greater than the preset long-chain alkane content, it is determined that the cracking reactor is heated up;

[0108] In a specific embodiment, the preset benzene series concentration is set to 1%, and if the benzene series concentration is 1.4% greater than the preset benzene series concentration, it is determined that the reactor is heated up and cooled down;

[0109] Optionally, the preset long-chain alkane content is 5% and the preset benzene series concentration is 1%.

[0110] Referring to Figure 3 As shown in the figure, it is a logic diagram for determining whether to open the exhaust valve of the embodiment of the present application, and the control unit further comprises:

[0111] A pressure sub-unit is connected to the cracking unit and the detection unit respectively, and is used to compare the cracking pressure with a preset pressure, and determine whether to open the exhaust valve according to the comparison result, the preset pressure being positively correlated with the feeding amount of the plastic raw material.

[0112] If the cracking pressure is greater than or equal to the preset pressure, it is determined that the exhaust valve is opened;

[0113] If the cracking pressure is less than the preset pressure, it is determined that the exhaust valve is closed;

[0114] In a specific embodiment, the preset pressure is set to 0.4 MPa, if the cracking pressure is 0.6 MPa which is greater than the preset pressure, it is determined that the exhaust valve is opened;

[0115] If the cracking pressure is 0.3 MPa which is less than the preset pressure, it is determined that the exhaust valve is closed;

[0116] It can be understood that the more the feeding amount of the plastic raw material, the greater the amount of gas generated per unit time, so the preset pressure is positively correlated with the feeding amount of the plastic raw material.

[0117] Please refer to Figure 4 The control unit further comprises:

[0118] A time sub-unit is connected to the cracking unit and the detection unit respectively, and is used to compare the carbon deposition rate with a preset carbon deposition rate, and determine whether the cracking reaction is completed according to the comparison result, the preset carbon deposition rate being positively correlated with the feeding amount of the plastic raw material.

[0119] If the carbon deposition rate is greater than or equal to the preset carbon deposition rate, it is determined that the cracking reaction is completed;

[0120] If the carbon deposition rate is less than the preset carbon deposition rate, it is determined that the cracking reaction is not completed;

[0121] In a specific embodiment, the preset carbon deposition rate is 5%, if the carbon deposition rate is 8% which is greater than the preset carbon deposition rate, it is determined that the cracking reaction is completed;

[0122] If the carbon deposition rate is 2% which is less than the preset carbon deposition rate, it is determined that the cracking reaction is not completed;

[0123] It can be understood that the more the feeding amount of the plastic raw material, the greater the amount of carbon deposition, so the preset carbon deposition rate is positively correlated with the feeding amount of the plastic raw material.

[0124] Further, the temperature sub-unit is further used for:

[0125] receiving the reaction kettle weight loss rate data detected by the detection unit in real time and the reaction kettle weight loss rate curve predicted by the thermal analysis sub-unit through thermal gravimetric analysis;

[0126] Based on the deviation AW of the reaction kettle weight loss rate based on real-time detection and the predicted reaction kettle weight loss rate, the main reaction temperature is dynamically adjusted, and only the numerical value is taken into account, including:

[0127] If AW > +5%, the temperature is compensated by increasing the temperature: ;

[0128] If AW < -5%, the temperature is compensated by decreasing the temperature: ;

[0129] Wherein, is the adjusted main reaction temperature, unit ℃; is the main reaction temperature before adjustment, unit ℃.

[0130] Specifically, the control unit further comprises:

[0131] The stirring sub-unit is connected with the cracking sub-unit and the detection sub-unit respectively, and is used to determine whether to reduce the stirring speed based on the olefin proportion, and to determine whether to increase the stirring speed based on the viscosity.

[0132] It can be understood that if the olefin proportion is greater than or equal to the preset olefin proportion, it is determined to reduce the stirring speed.

[0133] It can be understood that if the viscosity is greater than or equal to the preset viscosity, it is determined to increase the stirring speed.

[0134] In a specific embodiment, the preset olefin proportion is set to 60%, and if the olefin proportion is 72% greater than the preset olefin proportion, it is determined to reduce the stirring speed;

[0135] In a specific embodiment, the preset viscosity is set to 50 cP, and if the viscosity is 58 cP greater than the preset viscosity, it is determined to increase the stirring speed;

[0136] Optionally, the preset olefin proportion is 60%, and the preset viscosity is 50 cP.

[0137] Specifically, the present application improves the timeliness of monitoring the cracking process by adjusting the cracking-related parameters of the cracking reactor. By adjusting the related parameters of the cracking reactor, the system can quickly obtain real-time data during the cracking process. This real-time monitoring capability enables the system to promptly detect abnormal conditions or deviations during the cracking process and make rapid adjustments. Traditional cracking recovery systems may not be able to timely capture key changes in the cracking process due to delays in monitoring equipment or slow data processing speeds. The present application 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. Multi-dimensional data monitoring combined with parameter adjustment can reduce errors and uncertainties caused by changes in equipment, raw materials, or operating conditions. Traditional cracking recovery systems may have low cracking efficiency due to unreasonable parameter settings. The present application 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 handle different types of plastics, improving the system's versatility and adaptability, and further enhancing the accuracy of the waste polyolefin plastic cracking recovery system based on multi-dimensional data monitoring.

[0138] The scope of the present application is defined by the appended claims rather than by the description above, which is intended to be explanatory only. No admission is made herein that any reference constitutes prior art. The discussion of the references states what their authors assert, and applicants reserve the right to challenge the accuracy and pertinency of the cited references. Further, it will be clear that "including," "comprising," "incorporating," "has," "a" or "an," "by" or "contains" and other similar words mean "including but not limited to" and do not exclude other moieties, steps or materials. The singular encompasses the plural unless indicated otherwise. Also, it will be clear that "or" means "and / or" unless stated otherwise. Furthermore, it will be clear that "about" or "substantially" means "approximately," "around," or "in the order of" unless indicated otherwise. It will be clear that "even more preferably" or "preferred" or "preferably" means "even more preferred," "preferred," or "preferably," respectively, unless indicated otherwise.

[0139] The above description is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily make changes or replacements within the technical scope disclosed in the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be limited by the protection scope of the claims, and the above examples should be regarded as exemplary and non-limiting.

Claims

1. A waste polyolefin plastic pyrolysis recycling system based on multidimensional data monitoring, characterized by, The application relates to a waste polyolefin plastic pyrolysis system, which comprises the following units: a pretreatment unit for crushing, cleaning and drying waste polyolefin plastics to generate plastic raw materials; a collection unit connected with the pretreatment unit and used for collecting the water content, plastic density and component proportion of each monomer plastic of the plastic raw materials, and performing differential scanning calorimetry and thermogravimetric analysis on a representative plastic raw material sample to obtain thermodynamic parameters including a melting temperature, a cracking initiation temperature, a maximum weight loss rate temperature and a predicted residual carbon rate; a feeding unit connected with the collection unit and used for constructing a plastic feeding model based on the plastic density and the component proportion, adjusting a feeding amount based on the plastic feeding model and the water content, and associating the thermodynamic parameters with a feeding batch corresponding to a sampling period in real time; a cracking unit connected with the collection unit and the feeding unit and used for matching cracking process parameters according to the plastic feeding model, the water content, the feeding amount and the thermodynamic parameters corresponding to the feeding batch, and adjusting a cracking reaction kettle based on the cracking process parameters; a detection unit connected with the cracking unit and used for detecting cracking process parameters of the cracking reaction kettle, wherein the cracking process parameters include a cracking temperature, a cracking pressure and a cracking time, and detecting a cracking product including a cracking gas, a cracking liquid and a cracking solid; a control unit connected with the cracking unit and the detection unit and used for adjusting the cracking process parameters based on the cracking product and determining whether the cracking reaction is completed, and recording the cracking process parameters in a state where the cracking reaction is determined to be completed, and adjusting the cracking process parameters in combination with the plastic feeding model.

2. The waste polyolefin plastic pyrolysis recycling system based on multidimensional data monitoring according to claim 1, characterized in that, The collection unit comprises: a component subunit connected with the pretreatment unit and used for determining the component proportion of each monomer plastic of the waste polyolefin plastics based on image analysis and infrared spectroscopy; a measurement subunit connected with the pretreatment unit and used for measuring the plastic density based on a density gradient column method, and detecting the water content by a drying method; a thermal analysis subunit comprising a conveyor belt dynamic sampling device, a micro-differential scanning calorimeter and a thermogravimetric analyzer, which obtains a plastic raw material flow after drying through a pneumatic sampling valve installed in the middle of a conveyor belt of the conveyor belt dynamic sampling device, generates a representative sample through an automatic division device and delivers the sample to the micro-differential scanning calorimeter and the thermogravimetric analyzer for thermal analysis, specifically, differential scanning calorimetry test procedures are performed under a nitrogen atmosphere: the plastic sample is heated from room temperature to 300 DEG C at a constant temperature increasing rate of 20 DEG C / minute, and the melting temperature is determined by monitoring the heat absorption / heat release change of the sample; and thermogravimetric analysis test procedures are performed: the temperature is increased to 600 DEG C at a rate of 30 DEG C / minute to obtain the cracking initiation temperature, the maximum weight loss rate temperature and the predicted residual carbon rate.

3. The waste polyolefin plastic pyrolysis recycling system based on multidimensional data monitoring according to claim 2, characterized in that, The feeding unit comprises: a modeling subunit connected with the collection unit and used for calculating the weight ratio of each monomer plastic to construct the plastic feeding model according to the plastic density and the component proportion; The execution subunit is connected with the collection subunit and the modeling subunit respectively, and is used for comparing the water content with a preset water content, determining whether to start feeding according to a comparison result, and based on the weight ratio, regulating the feeding amount in a state of determining to start feeding; The preset water content is positively correlated with the weight ratio of the polar plastic.

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

5. The waste polyolefin plastic pyrolysis recycling system based on multidimensional data monitoring according to claim 4, characterized in that, The process subunit selects a plurality of cracking process parameters of the same plastic density and the same composition according to the plastic feeding model, and calculates a difference value according to the water content and the feeding amount, and determines optimal cracking process parameters according to the difference value and the thermodynamic parameters, comprising: The temperature curve and the time parameter dynamically calculated according to the thermodynamic parameters replace the temperature curve and the time parameter in the first cracking process parameters to obtain the optimal cracking process parameters. According to the plastic density difference ≤ ± 0.02 g / cm 3 And the component proportion difference ≤ ± 3% from the historical process parameter library, get a number of candidate groups of the cracking process parameters; The difference value δ is calculated according to the following formula, only the numerical value is taken, the three groups of historical parameters with the minimum difference value δ are taken, and then a weighted average is generated to generate the first cracking process parameter; wherein the difference value δ wherein is the current water cut; is the historical water cut; is the current feed rate, unit Kg; is the historical feed rate, unit Kg; The temperature curve and the time parameter are dynamically calculated based on the thermodynamic parameters, comprising:

6. The waste polyolefin plastic pyrolysis recycling system based on multidimensional data monitoring according to claim 5, characterized in that, Taking a cracking starting temperature Tonset as a reference, an initial temperature rising section end point temperature is set: initial end point temperature = Tonset - 20 °C; Taking a maximum weight loss rate temperature Tmax as a main reaction zone temperature set point: main reaction temperature = Tmax ± 10 °C; According to a predicted residual carbon rate Char, a final holding temperature is set: if the predicted residual carbon rate Char > 8%, the final holding temperature = Tmax + 30 °C, otherwise, the final holding temperature = Tmax + 10 °C; Based on a difference between a melting temperature Tm and the cracking starting temperature Tonset, a material homogenization time is calculated: homogenization time = (Tonset - Tm) × 0.5, unit: min; A main reaction time T = W × 2.5; wherein the unit of the main reaction time T is min, and W is a mass loss interval width, and only a numerical value is taken in calculation, and W is specifically a 90% mass loss interval width in a thermogravimetric analysis test program. The detection unit comprises: The parameter detection subunit is connected with the cracking unit, and is used for inserting a temperature measuring end of a thermometer into a material center to measure the cracking temperature, and measuring the cracking pressure of a gas phase space in an upper part of the cracking reactor through a pressure sensitive element.

7. The waste polyolefin plastic pyrolysis recycling system based on multidimensional data monitoring according to claim 4, characterized in that, The detection unit further comprises: ​ 8. The waste polyolefin plastic pyrolysis recycling system based on multidimensional data monitoring according to claim 7, characterized in that, ​ A product detection subunit connected with the cracking unit, for detecting the long-chain alkane content and benzene series concentration of the cracking gas by gas chromatography, and measuring the viscosity and olefin proportion of the cracking liquid by a Brookfield viscometer, and obtaining the coke deposition rate by sampling the cracking solid on the inner wall of the cracking reactor.

9. The waste polyolefin plastic pyrolysis recycling system based on multidimensional data monitoring according to claim 8, characterized in that, The control unit comprises: A temperature subunit connected with 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 with the cracking unit and the detection unit respectively, for comparing the cracking pressure with a preset pressure, and determining whether to open an exhaust valve according to the comparison result, the preset pressure being positively correlated with the feeding amount of the plastic raw material; A time subunit connected with the cracking unit and the detection unit respectively, for comparing the coke deposition rate with a preset coke deposition rate, and determining whether the cracking reaction is completed according to the comparison result, the preset coke deposition rate being positively correlated with the feeding amount of the plastic raw material; A stirring subunit connected with the cracking unit and the detection unit respectively, for determining whether to decrease the stirring rate based on the olefin proportion, and determining whether to increase the stirring rate based on the viscosity.

10. The waste polyolefin plastic pyrolysis recycling system based on multidimensional data monitoring according to claim 9, wherein, The temperature subunit is further configured to: receive the reactor weight loss rate data detected by the detection unit in real time and the reactor weight loss rate curve predicted by the thermal analysis subunit through thermal gravimetric analysis; compare the deviation AW between the reactor weight loss rate detected in real time and the predicted reactor weight loss rate, and dynamically adjust the main reaction temperature, and only take the numerical value when calculating, including: If ΔW > +5%, increase temperature compensation: ; If ΔW < -5%, temperature compensation: ; wherein, is the adjusted main reaction temperature, in °C; is the unadjusted main reaction temperature, in °C.

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