Method and system for controlling and / or regulating a production facility configured to manufacture thermoplastics

Abstract

The invention relates to a method for controlling and / or regulating a production facility which is configured to manufacture thermoplastics. The invention further relates to an apparatus and a system for carrying out the method. In order to reduce fluctuations in product quality, the invention proposes the following method steps: detecting a pressure value in the production facility; determining an estimate indicating viscosity at least partially based on the detected pressure value and at least partially based on a temperature dependency of the viscous behavior of the thermoplastic and at least partially based on a temperature dependency of a volume flow; and determining a viscosity value indicating the viscous behavior of the thermoplastic at least partially based on a correction factor, wherein the correction factor indicates a facility state and wherein the facility state is determined at least partially by at least one main production parameter.

Description

Technical Field

[0001] The invention relates to a method for controlling and / or regulating a production facility which is configured to produce thermoplastics. The invention also relates to an apparatus and a system for carrying out the method. Background Art

[0002] The process used on a large scale for producing polycarbonates is the melt polycarbonate (SPC) process. Polycarbonates produced according to the so-called melt transesterification process (also called melt process) from organic carbonates such as diaryl carbonates and bisphenols in the melt without the use of additional solvents are becoming increasingly economically important and are therefore suitable materials for many areas of application. The production of aromatic polycarbonates by the melt transesterification process is known and is described, for example, in “Schnell”, Chemistry and Physics of Polycarbonates, Polymer Reviews, Vol. 9, Interscience Publishers, New York, London, Sydney 1964, in “Synthesis of Poly(ester)carbonate Copolymers” by DC Prevorsek, BT Debona and Y. Kersten, Corporate Research Center, Allied Chemical Corporation, Moristown, New Jersey 07960, Journal of Polymer Science, Polymer Chemistry Edition, Vol. 19, 75-90 (1980), in “Polycarbonates” by D. Freitag, U. Grigo, PR Müller, N. Nouvertne, BAYER AG, Encyclopedia of Polymer Science and Engineering, Vol. 11, 2nd edition, 1988, pages 648-718 and finally in Des. U. Grigo, K. Kircher and PR Müller, “Polycarbonate”, Becker / Braun, Kunststoff-Handbuch, Band 3 / 1, Polycarbonate, Polyacetale, Polyester, Celluloseester, Carl Hanser Verlag München, Wien 1992, pages 117-299.

[0003] At the end of the production method, the thermoplastic produced is pelletized in a conventional manner in order to simplify its use as raw material within the scope of subsequent processing methods.

[0004] Polycarbonate can be processed using all common methods for thermoplastics. The viscosity of the material to be processed is very important, for example in injection molding. In order to produce products with properties suitable for these finishing methods and to achieve the required product quality, viscosity setpoints are predefined during the production of polycarbonate.

[0005] In the manufacture of thermoplastics such as polycarbonate, the real viscosity, that is, the actual viscosity of the manufactured plastic, can be influenced by means of controlled processes on the one hand, and by means of uncontrolled processes on the other hand. For example, the raw materials used for manufacture can be selected according to their influence on the viscosity of the plastic, which represents a controlled process that influences the viscosity. In addition, many uncontrolled factors may cause the real viscosity to change over time. These factors may be parameters related to the production facility (such as wear), or may be factors that are difficult to control, such as the ambient temperature that varies with the seasons at the production site. In particular, the actual viscosity of the manufactured plastic may change during the operation of the facility, for example due to fluctuations in the quality of the raw materials (impurity ratio, etc.), due to fluctuations in the ratio between two raw materials (such as DPC and BPA) and / or due to fluctuations in the pressure regulation of the various reactors that contribute to the production. In addition, product changes and changes in flow and load in the process may also cause the actual viscosity of the manufactured plastic to change.

[0006] Therefore, the actual viscosity of the produced plastic is monitored and the control of the production facility is adapted accordingly.

[0007] In order to carry out such monitoring or control of the production facility, in a known type of manufacturing method, samples are collected from the production facility during manufacturing and at specific discrete time intervals (for example, at a sampling rate of 1 to 4 hours). The collected samples are then analyzed and evaluated. By default, the evaluation provides one or more of the following information about the sample: MVR (melt volume-flow rate), MFI (meltflow index), V number (viscosity coefficient), solution viscosity, degree of branching or color (YI) and, in most cases, molecular weight. This information indicates the viscous behavior of the sample. The variables obtained by evaluating the sample are referred to as measured values ​​hereinafter.

[0008] The analysis and the evaluation can be carried out, for example, with the aid of the measurement method described in the Thomas Mezger handbook: Das Rheologie-Handbuch, 3. Print 2000, Vincentz Network GmbH & C, (page 332) so that the viscosity can be determined. The V value is related to the relative viscosity, for example, which is measured for a polymer concentration of 0.5% in dichloromethane. The value of MVR itself can be measured for highly viscous materials at 300° C. with a weight of 1.2 kg in a standardized device, for example according to standard DIN EN ISO 1133-1. In addition, it is well known that the following relationship exists between the V number and the MVR value: MVR=a*(V number) b , where a and b are relative real constants.

[0009] To evaluate a measured value of the type mentioned at the outset, the measured value is then compared in a known manner with a viscosity setpoint value which is predefined within the context of product quality. Based on the continuous sample collection, sample evaluation and the comparison, it can be assessed to what extent the control of the production facility needs to be adapted in order to bring the viscosity closer to the setpoint value.

[0010] Most manufacturing processes for thermoplastics such as polycarbonate are run continuously. In other words, the production facilities are mostly operated without interruption, in particular for economical manufacturing. Since the above-mentioned sample collection and evaluation of the properties of the manufactured plastic are carried out punctually at time intervals corresponding to the dead time, the control of the facility is adapted accordingly punctually. Due to the difference between the continuous nature of the manufacturing and the discrete nature of the measurement or adaptation of the control, the actual viscosity of the manufactured plastic will show irregularities over time. This ultimately affects the product quality and can result in a large number of rejects.

[0011] Furthermore, when evaluating the collected samples, it is difficult to take into account factors related to the production facility that may influence the viscosity of the manufactured plastic. Usually, only known factors, such as the temperature dependence of the viscosity, are taken into account in the evaluation. This results in a difference between the real viscosity and the measured value provided by the evaluation.

[0012] Thus, US5412060A discloses a method for producing polycarbonate with particularly uniform relative viscosity, even over long production times and when a continuous reaction is started and stopped, in which the influence of disturbances of feed quantity and raw material concentration on the V number is detected and used to adjust the dosage of the raw material taking into account the time delay between the dosage and the effect of the dosage on the measured variable. In this document, the difference between the prediction and the measurement is determined, for example in the form of statistics by variance and mean value or in the form of a white noise test. If there is a deviation from the expected value, these statistics are used to adapt the estimated dynamics. In addition, these deviations are monitored to identify disturbances.

[0013] Furthermore, US4425790A discloses a method and apparatus for rheologically characterizing thermoplastic polymers. In particular, US4425790A relates to continuous, real-time measurement of the viscosity of a polymer over a wide range of shear rates, wherein the extrusion properties of the polymer can be predicted.

[0014] However, it has been found that the prior art methods are difficult to operate because it is difficult to determine the viscosity directly in an ongoing production.

[0015] For the control of the production facility, the viscosity can be influenced in a simple manner, for example by changing the pressure (or vacuum) in the viscosity reactor. In addition, the reactor temperature, the residence time and / or the ratio of the reactants can be varied. Summary of the invention

[0016] Starting from this prior art, the object of the present invention is to provide a method for controlling and / or regulating a production facility which is configured to produce thermoplastics, which method avoids or reduces the above-mentioned problems and in particular allows fluctuations in product quality to be minimized.

[0017] In order to achieve this object technically, the invention proposes a method for controlling and / or regulating a production facility which is configured to produce thermoplastics, the method comprising:

[0018] - detecting the pressure value in the production facility;

[0019] - determining an estimate of the indicative viscosity based at least in part on the detected pressure value and at least in part on the temperature dependency of the viscous behavior of the thermoplastic and on the temperature dependency of the volume flow; and

[0020] - determining a viscosity value indicative of the viscous behavior of the thermoplastic at least partially as a function of a correction factor, wherein the correction factor is indicative of a plant state, and wherein the plant state is at least partially determined by at least one main production parameter.

[0021] The state of the production facility may change, for example due to a change in product type with a different viscosity rating and the transition phases inherent in the change. Furthermore, sensors may change over time and have an offset, which then continues to be substituted into the prediction of the viscosity. Volume flow measurements may also have deviations. Fouling and / or clogging may occur in static mixers, but may also occur in other facility parts and thereby change the state of the production facility (e.g. change in pressure loss, change in heat transfer).

[0022] The correction according to the invention allows a rapid reaction to changes in the state of the plant, thereby minimizing fluctuations in product quality.

[0023] On the one hand, the invention is based on the recognition that the viscosity of the manufactured plastic can be detected in real time or continuously by determining an estimated value indicating the viscosity at least partly based on the pressure value detected in the production facility. In other words, the viscosity of the manufactured plastic can be determined without dead time, that is to say in a continuous manner. The control of the production facility can thus be continuously adapted corresponding to the set viscosity setpoint value. As a result, the actual viscosity of the manufactured plastic is continuously kept close to the setpoint value, thereby improving the overall product quality.

[0024] Furthermore, this provides the possibility of detecting undesired disturbances which may occur during the operation of the manufacturing process and which affect the viscosity of the produced plastic, and of adapting the control of the production facility accordingly, thereby producing fewer rejects and thus improving the product quality overall.

[0025] On the other hand, the invention is based on the recognition that taking into account the correction factor KF offers the possibility of improving the product change process. Different products produced successively in the same production facility within the scope of the product change process may have different properties. These differences, in particular differences in the viscosity behavior of the various products, can be taken into account in the correction factor. Thus, by changing the correction factor, changes in the plastic produced can be taken into account and the viscosity can be determined continuously without further effort, which is adapted to the plastic currently being produced.

[0026] Changes in the state of the production facility, such as changes in conditions in the production facility due to scaling or sensor deviation (offset) or volume flow deviation and product changeover processes, can be mapped by the correction factor so that the facility state can be quickly adapted and products with desired specifications and minimized negative impact on product quality can be produced.

[0027] In the context of the present invention, the term "production facility" is to be understood in particular as a facility which is an arrangement of at least one device, each of which is configured to participate at least partially in the production of thermoplastics. In particular, the meaning of the present invention should include production facilities which are configured to produce polycarbonate in stages with respect to temperature and pressure. The temperature can be set in stages within a range of 150° C. to 400° C., wherein the residence time in each stage can be 15 minutes to 5 hours, and the pressure in each stage can be 1000 mbar to 0.01 mbar (millibar). Particularly preferably, the temperature increases gradually from one stage to another and the pressure decreases gradually from one stage to the next.

[0028] The production facility may have at least one or more devices that are configured to facilitate the production process of thermoplastics. Such equipment may, for example, be and / or include one or more of the following facilities:

[0029] - pressure sensor;

[0030] - Intake facilities for raw materials used to manufacture plastics;

[0031] - blending facilities arranged to blend raw materials;

[0032] -catalyst;

[0033] - Aggregation facilities;

[0034] - capacitors;

[0035] - Vacuum pump;

[0036] - Transmission facilities;

[0037] - a reactor configured to adjust the viscosity of the plastic; and

[0038] -Static mixer.

[0039] Typically, a static mixer is used in the process environment described to mix additives into the main stream, generally to achieve dispersion in multiple stages or when mixing different components or to improve heat transfer. The static mixer can be configured accordingly by a person skilled in the art on the basis of the prior art, for example according to one of the documents US4062524, DE2532355, US6394644, EP1617980 or EP2255947. The residence time is between 1 second and 600 seconds, preferably between 10 seconds and 100 seconds, particularly preferably between 20 seconds and 60 seconds. The introduction of the static mixer is accompanied by a pressure loss over its entire length.

[0040] Preferably, the pressure in the production facility is detected by means of a device for detecting pressure, wherein the pressure can be detected individually or at a plurality of locations in the production facility. By detecting the pressure at a plurality of locations in the production facility, a comparison can be made, for example, to obtain information about the pressure drop, such as a differential pressure value. The differential pressure value can in particular correspond to the difference between a first pressure detected at a first location, for example before a static mixer of the production facility, and a second pressure detected at a second location, for example after the static mixer.

[0041] The pressure difference can be detected in particular by means of the static mixer. For this purpose, the static mixer can introduce flow resistance due to the design of the internal components for dispersion. This results in a pressure difference or pressure loss over the entire length of the static mixer, which can be characterized by a pressure value. The static mixer is preferably arranged in the production facility downstream of the viscosity reactor and downstream of the discharge pump.

[0042] In the meaning of the present invention, the term "pressure value" is to be understood as a value indicating the pressure or pressure difference (e.g., a differential pressure value) in the production facility. This can be an absolute value or a relative value. A relative value such as a differential pressure value can be derived from the difference between a pre-set value and a current value. Similarly, a differential pressure value can be derived from the difference between a value determined and recorded in a previously performed acquisition process and the current value. Here, the term "pressure value" is to be understood in particular as the difference between the pressure detected before the equipment of the production facility and the pressure detected after the equipment. Therefore, such a pressure value corresponds to the pressure difference between the inlet and the outlet of the equipment in question. If the equipment in question is arranged between two adjacent stages in the production facility, such a pressure value corresponds to the pressure drop between these two stages. In the following, the pressure value is referred to as D mess .

[0043] The above estimated value indicating the viscosity is to be understood as the value obtained by calculating the previously detected pressure value D in the aforementioned determined range. mess To convert the detected pressure value D mess , for example, a calculation can be performed in which the correlation between pressure and viscosity is used. For this purpose, for example, the so-called Hagen-Poiseuill law can be used, which, by selecting the corresponding parameters, makes it possible to take into account the temperature dependence of the viscous behavior of the thermoplastic involved. In the following, for the sake of simplicity, the estimated value indicating the viscosity is referred to as V g .

[0044] It has been shown that such theoretical correlations alone cannot reflect the process, i.e. differences may occur between the viscosity values ​​determined with the aid of the correlations and the laboratory measured values. The laboratory value feedback is preferably carried out by means of a deviation update, so that possible changes in the correlation over time can be detected. In this way, the deviations between the predictions and the laboratory measurements can be minimized.

[0045] According to the invention, a viscosity value indicative of the viscous behavior of the thermoplastic is determined at least in part based on a correction factor. To simplify understanding, this viscosity value is referred to below as V KF For example, based on the estimated value V g And determine V by taking into account the correction factor KF KF Since the correction factor indicates the facility status and the facility status is at least partially determined by at least one main production parameter, interference factors related to the production facility can be taken into account in the correction factor. KF Corresponding to a ratio such as V g A viscosity that is closer to the actual viscosity of the plastic being manufactured.

[0046] In a first embodiment of the method, the correction factor KF corresponds to a result based on a statistical calculation based on an estimated value V indicating the viscosity g Compared with the viscosity V measured in the laboratory labor The historical value of the relationship between the two. From this, the viscosity value V is calculated KF When calculating the production cost, on the one hand, factors related to the production facilities can be taken into account, and on the other hand, unpredictable interference factors can be taken into account.

[0047] In a first implementation, the viscosity V measured in the laboratory is calculated using the correction factor KF. labor With the estimated value V g The difference (i.e. using KF = V labor -V g ) and the specific characteristics of the sample collected to calculate the viscosity V KF , the specific characteristic is linearly proportional to the pressure loss (e.g. V number) on the static mixer. This implementation results in that it is advantageously possible to labor and V g In this implementation, V can be expressed by a linear dependency based on constant adaptive parameters d1, d2, d3. g .

[0048] In another embodiment, the characteristic of the sample collected is inversely proportional to the pressure difference across the static mixer (eg, MVR). Here, the relationship KF=1 / V is selected. labor -1 / V g , so that by the 1 / Vlabor and 1 / V g In this implementation, 1 / V can be expressed by a linear dependence based on constant adaptive parameters d1, d2, d3. g .

[0049] In another embodiment, the characteristic of the sample collected is inversely proportional to the pressure difference across the static mixer (eg, MVR). Here, the relationship KF=(V labor / a)^ l / b -(V g / a)^ l / b , so that by (V labor / a)^ l / b and (V g / a)^ l / b The correction factor KF is expressed by a linear dependence of . In this implementation, it can be expressed by a linear dependence based on constant adaptive parameters d1, d2, d3 (V g / a)^ l / b .

[0050] The term "laboratory viscosity" is to be understood as meaning in particular the result of at least one laboratory experiment in which a sample taken from the production facility was analyzed. Such a laboratory viscosity thus corresponds to the directly measured viscosity of the plastic produced by the production facility. Such a viscosity is hereinafter referred to as V labor Furthermore, the laboratory values ​​and possible noise in the facility sensors are filtered to reduce the impact on the calculation of the correction factor KF.

[0051] The historical value, for example, indicates the estimated value V g With laboratory viscosity V labor The historical value thus corresponds, for example, to a possible difference between a directly measured viscosity behavior and a viscosity behavior estimated by theoretical calculation. By accumulating a plurality of such historical values ​​over time, the course of change or history of this relationship can be reproduced. This course of change can then be evaluated by statistical calculations in order then, for example, to be used in calculating the viscosity value V KF is taken into account in the correction factor.

[0052] In another embodiment of the method, the at least one main production parameter indicates one or more of the following characteristic values ​​i) to iii):

[0053] i) temperature of the plastic;

[0054] ii) pressure;

[0055] iii) The volume flow through the production facility.

[0056] The viscosity value V is thus calculated using the correction factor KF When calculating the production parameters, the changes in these production parameters or the influence of individual production parameters can be taken into account.

[0057] The viscosity value V is preferably calculated as follows KF , where the temperature T, the measured pressure difference D mess and the volume flow S flowing through the facility. KF Normalized to the temperature measured in the laboratory (T labor ).

[0058] In the implementation in which the viscosity is proportional to the pressure loss over the static mixer (eg V value), the following relationship is obtained

[0059] [V KF (T)]=[f(T) / S]*[(D mess *d1)+d2]+d3+KF.

[0060] In the implementation where the viscosity is inversely proportional to the pressure loss across the static mixer (eg MVR), it follows that

[0061] [1 / V KF (T)]=[f(T) / S]*[(D mess *d1)+d2]+d3+KF.

[0062] In which V~a*(D mess )^b form of the pressure loss D on the static mixer mess In the implementation of the nonlinear dependence of the viscosity, the constants a and b are used to obtain

[0063] [V KF (T) / a] ∧(1 / b) =[f(T) / S]*[(D mess *d1)+d2]+d3+KF.

[0064] Here, d1, d2 and d3 are constants that are dependent on the plastic being produced. These constants (values) are usually initially determined without KF values ​​by a least squares fit between laboratory values ​​and operating data. The exact values ​​are therefore plant- and / or product-specific.

[0065] Here, f(T) is the temperature correction and can be expressed as follows:

[0066] f(T)=exp(-T) / exp(-T labor ),

[0067] It is preferably assumed that the temperature Tlabor =300℃.

[0068] The correction factor KF is then obtained during ongoing operation by adaptation (deviation updating).

[0069] In another embodiment of the method, the historical value indicates the facility status and the type of the thermoplastic. For example, the previously detected historical value is at least partially based on the facility status and the type of the thermoplastic. KF The type of plastic currently being manufactured can be taken into account when calculating V. Since different types of plastics generally have different viscosity behaviors, the calculated V KF The value is close to or corresponds to V real .

[0070] In another embodiment of the method, the historical values ​​are the result of a series of measurements. A series of measurements is understood here to mean that the sample collection and the viscosity of the sample are repeatedly performed within a specific period of time and at specific time intervals. Thus, a series of historical values ​​can be obtained. Then, a statistical calculation based on the historical values ​​provides V within the time period of the series of measurements. g With V labor The changing process of the relationship between them.

[0071] The series of measurements can be performed, for example, once. However, it is preferred to repeat the series of measurements in order to calculate V KF Consider V g With V labor The first type of plastic is defined by at least one of the following variables: molecular weight, branching of the polymer chain of the plastic, solution viscosity, color (YI) and / or melt volume flow rate (MVR) or melt flow index (MFI). It is understood that different types of plastic can be provided.

[0072] In another embodiment of the method, the method further comprises the following steps:

[0073] - comparing the viscosity value determined and indicative of the viscous behavior of the thermoplastic with a setpoint viscosity value;

[0074] - determining at least one adjustment information, said adjustment information being based at least in part on a result of said comparing; and

[0075] - outputting the determined regulation information or initiating the output of the determined regulation information, wherein the production facility can be controlled and / or regulated based on the determined regulation information.

[0076] This provides, on the one hand, information on the viscosity of the produced plastic in real time and, on the other hand, the possibility of adapting the control of the production plant to the viscosity behavior of the produced plastic with respect to the viscosity to be achieved.

[0077] It is then possible to carry out meaningful regulatory interventions based on the information obtained, for example to change the pressure in one or more viscous reactors.

[0078] The term "nominal viscosity value" is to be understood as a predefined value, for example within the range of a demand curve for production. The nominal viscosity value may vary between the type of plastic to be manufactured and other types of plastic. In the following, the nominal viscosity value is referred to as V soll .

[0079] The viscosity value V indicates the viscous behavior of the thermoplastic KF The result of the comparison with the setpoint viscosity value may provide an absolute difference or a value within a tolerance range around the setpoint viscosity value.

[0080] The adjustment information preferably indicates one of the above-mentioned production parameters. Here, the adjustment information corresponds to the viscosity value V KF For the value to be achieved for one or more production parameters, the viscosity value V KF As close as possible to or equal to the rated viscosity value V soll .

[0081] In a further embodiment of the method, the production facility is controlled and / or regulated at least partially as a function of the control information, thereby resulting in a control loop which allows at least the type of plastic produced and the state of the facility to be taken into account in order to approximate the viscosity of the produced plastic to the setpoint viscosity value.

[0082] In the context of the present invention, the term "regulation" is understood to mean a process according to the DIN IEC 60050-351 standard, in which the variable of the detected manipulated variable is continuously compared with another variable, namely a reference variable, and the variable of the detected manipulated variable is influenced in a manner similar to the reference variable. The characteristic of the regulation is a closed action sequence, in which the manipulated variable continuously influences itself in the action path of the control loop. In contrast, control only includes the setting of a variable provided according to the control, without the variable continuously influencing itself.

[0083] The manipulated variable is the pressure value D mess , which is detected in the production facility. In addition, the reference variable is the rated viscosity value V soll As mentioned above, based on the pressure value D mess Calculated viscosity value V KFWith rated viscosity value V soll A comparison is made between the two for said adjustment.

[0084] In a further embodiment of the method, the method forms a control loop and is run continuously or discretely at predefined time intervals during the production of the thermoplastic.

[0085] By running the control continuously, the difference between the continuous nature of the manufacturing process and the discrete nature of the sample collection for laboratory experiments described at the beginning can be compensated. So-called dead times of the type mentioned at the beginning are thus avoided, and devices with short response times can be used in the production facility. In addition, the viscosity of the produced plastic can be compensated in real time with respect to the setpoint viscosity value V soll The deviation between .

[0086] In another embodiment of the method, the method further comprises the following steps:

[0087] A product change of the thermoplastic produced by the production facility from a first type of thermoplastic to a different type of thermoplastic is carried out, wherein the control loop continues to operate.

[0088] Thus, two different types of plastic produced successively by the production facility can be taken into account in the control. Since the control loop continues to run, that is, since the switchover is made between two correction factors that are respectively dependent on the type of plastic, bad and / or defective products are reduced or minimized during product changes.

[0089] In a further embodiment of the method, in order to determine the viscosity value which indicates the viscous behavior of the thermoplastic after the product change, the correction factor is based on historical values ​​which at least partially indicate other types of thermoplastics. In particular, the correction factor KF can be calculated based on the historical values ​​using a Kalman filter, a median filter or an nth-order delay element (PTn). This allows, for example, not only the plastic properties known from the literature to be taken into account, but also components that are related to the plant conditions and / or production conditions. As a result, the product quality can be improved.

[0090] The object according to the invention is also achieved by a device which is designed to carry out and / or control one or more of the above-described methods or comprises corresponding means for carrying out and / or controlling the steps of one or more of the above-described methods.

[0091] The device of the device according to the present invention may include hardware components and / or software components. The device may, for example, include at least one memory having program instructions of a computer program and at least one processor configured to execute the program instructions from the at least one memory. Therefore, according to the present invention, it should also be understood that a device is disclosed, the device includes at least one processor and at least one memory having program instructions, wherein the at least one memory and the program instructions are configured to cause the output module or the sensor module to perform and / or control the method according to the first aspect or the second aspect of the present invention together with the at least one processor.

[0092] Alternatively or additionally, the device's apparatus may further include one or more sensors and / or one or more communication interfaces.

[0093] A communication interface is to be understood as meaning, for example, a wireless communication interface and / or a wired communication interface.

[0094] The wireless communication interface is, for example, a communication interface according to a wireless communication technology. Examples of wireless communication technologies are local radio network technologies such as radio frequency identification (RFID) and / or near field communication (NFC) and / or Bluetooth (e.g., Bluetooth version 2.1 and / or 4.0) and / or wireless local area network (WLAN). For example, RFID and NFC are specified according to ISO standards 18000, 11784 / 11785 and ISO / IEC standards 14443-A and 15693. For example, WLAN is specified in the standards of the IEEE802.11 series. Another example of wireless communication technology is a super local area radio network technology, such as a mobile radio technology, such as a global system for mobile communications (GSM) and / or a universal mobile telecommunications system (UMTS) and / or a long term evolution (LTE). The GSM, UMTS and LTE specifications are maintained and developed by the Third Generation Partnership Project (3GPP).

[0095] The wired communication interface is, for example, a communication interface according to a wired communication technology. Examples of wired communication technologies are local area networks (LAN) and / or bus systems, such as controller area network bus (CAN bus) and / or universal serial bus (USB). The CAN bus is, for example, specified according to ISO standard ISO11898. LANs are, for example, specified in the standards of the IEEE802.3 series. It is understood that the output module and / or the sensor module may also include other devices not listed.

[0096] Furthermore, according to the present invention, a computer program is disclosed, which includes program instructions, and the program instructions are configured to cause a device to execute and / or control the method according to the first aspect and / or the second aspect of the present invention or the system according to the present invention when the computer program is executed by a processor.

[0097] In addition, a computer-readable storage medium is disclosed, which contains a computer program according to the present invention. The computer-readable storage medium can be constructed as, for example, magnetic, electrical, electromagnetic, optical and / or other types of storage media. Such a computer-readable storage medium is preferably tangible (i.e., "touchable"), for example, constructed as a data carrier device. Such a data carrier device is, for example, portable or fixedly installed in a device. Examples of such data carrier devices are volatile or non-volatile memories (e.g., NOR flash memory) with random access (RAM) or volatile or non-volatile memories (e.g., NAND flash memory) with sequential access and / or a memory (ROM) with read-only access or a memory with read / write access. For example, computer readable should be understood as a storage medium that can be read and / or written from a computer or server device, for example, by a processor.

[0098] In the context of the present invention, the term "control" is generally understood to mean influencing one or more production parameters via one or more devices. Such control includes regulation based on a comparison between an actual value and a setpoint value, wherein, for example, the controlled production parameter then influences further iterations of the production parameter regulated in this way. In the present case, this is V KF With V soll Compare between.

[0099] The device may represent the entire production facility or at least a part of a production facility. Other facilities that contribute to the manufacture of thermoplastics may also be considered as devices within the meaning of the present invention or included in the device.

[0100] In a first embodiment of the device, a viscosity reactor is provided. This has the advantage that, for example, such a viscosity reactor can be included in the above-mentioned control circuit. Thus, the viscosity of the produced plastic can be adapted by adjusting the viscosity reactor. In particular, the viscosity can be influenced by setting a pressure, more precisely a vacuum, in the high-viscosity reactor.

[0101] In this case, the static mixer for determining the pressure difference is preferably arranged downstream of the discharge pump and at the outlet of the viscous reactor.

[0102] A viscosity reactor is to be understood as a reactor which is designed specifically to influence the viscosity of the produced plastic, for example by influencing the pressure in the reactor. For example, a disk reactor is used. The disk reactor mixes and has the task of creating a large surface by pulling the viscous mass upwards almost as a film. This, for example, causes the solvent to evaporate. The viscosity increases with increasing reactor length / reaction time.

[0103] The viscosity varies with residence time. More than one reactor designed for different viscosities or viscosity ranges may be used.

[0104] The object according to the invention is also achieved by a system comprising one or more devices which are together constructed and / or arranged to perform one or more of the above-mentioned method steps. The system comprises, for example, a detection device for detecting a pressure value in a production facility, a determination device for determining an estimated value indicative of viscosity, wherein the determination is based at least in part on the detected pressure value and at least in part on the temperature dependence of the viscous behavior of the thermoplastic, and a determination device for determining a viscosity value indicative of the viscous behavior of the thermoplastic, wherein the determination is based at least in part on a correction factor indicative of a facility state, and wherein the facility state is at least in part determined by at least one main production parameter.

[0105] In a first embodiment of the system, an input device is provided for inputting historical values ​​and / or for inputting setpoint viscosity values. As a result, historical values ​​and / or setpoint viscosity values ​​can be taken into account when controlling and / or regulating one or more devices of the system, which historical values ​​were not generated by the system itself or are not yet stored in the system.

[0106] Such an input is particularly useful for setting a target viscosity value which is not known in advance to the system (for example for the production of new plastics).

[0107] In a further embodiment of the system, a determination device is provided for determining at least one adjustment information item, wherein the determination is based on a comparison between a determined viscosity value indicating the viscous behavior of the thermoplastic and a setpoint viscosity value.

[0108] The determining means may be, for example, a computer readable storage medium or a device according to the apparatus described above.

[0109] In a further embodiment of the system, an output device is provided for outputting the at least one control information determined. This enables communication between the devices of the system that participate in the control loop. Thus, for example, the control information can first be determined by the determination device and then output by the output device in order to be subsequently transmitted to the control device.

[0110] In another embodiment of the system, a regulating device is provided, which is configured to perform a control and / or regulation of one or more devices, wherein the control and / or regulation is at least partially based on the determined at least one regulating information.

[0111] The term "regulating device" is to be understood in particular as a device which is arranged in a regulating circuit to be connected between at least one device for detecting a pressure value and at least one control device of at least one device of the system. Preferably, such a control device is arranged to influence a production parameter, for example the pressure. In this case, the regulating device can have and / or include an estimated value V for calculating the viscosity. g Device for calculating the viscosity value V KF Device for storing the measured true viscosity V labor means for storing historical values ​​and at least one nominal viscosity value V soll means for comparing at least two of these values ​​with each other and means for transmitting information between the means for detecting pressure values ​​and said control means. BRIEF DESCRIPTION OF THE DRAWINGS

[0112] Figure 1 A schematic diagram shows a design for a method for controlling and / or regulating a production facility configured to manufacture thermoplastics; and

[0113] Figure 2 The schematic diagram shows the method for executing Figure 1 Methods for the design of systems. DETAILED DESCRIPTION

[0114] Figure 1 The schematic diagram shows a design of a method for controlling and / or regulating a production facility configured to produce thermoplastics. In the following, the steps of the method shown are indicated with Roman numerals to aid understanding. Figure 1 The following steps are shown in:

[0115] I: Detection pressure value D mess ;

[0116] II: Determine the temperature correction f(T) and determine the volume flow S;

[0117] III: Determine the estimated viscosity value V g (T);

[0118] IV: Through V g (T) and V labor The comparison between them determines the historical value;

[0119] V: According to f(T), D mess , volume flow S and correction factor KF to determine the viscosity value V KF (T);

[0120] VI: In V KF (T) and V soll Compare between;

[0121] VII: determining adjustment information RI according to the comparison result; and

[0122] VIII: Depending on the RI, for example, the pressure in the system is influenced.

[0123] Steps I to VIII are performed sequentially in the above order.

[0124] exist Figure 1 The other step marked L in the above corresponds to determining the laboratory viscosity V by selectively collecting a sample and directly measuring the viscosity of the collected sample. labor .

[0125] In a first step I, a first pressure before a device of the production facility and a second pressure after the device are measured in the distribution of the production facility. The difference between the first pressure and the second pressure is calculated, from which a pressure value D is determined. mess . Thus D mess Corresponds to the pressure difference between the inlet and the outlet of the device.

[0126] In a second step II, the temperature correction f(T) and the volume flow S are determined.

[0127] In a third step III, the pressure value D is introduced into the Hagen-Poisson correlation between pressure and viscosity and taking into account the temperature dependency. mess This gives an estimated value V g (T), this estimated value represents the viscosity and depends on the temperature T.

[0128] In the fourth step IV, the value V obtained from step III g (T) and the viscosity V determined in step L labor The relationship between the actual directly measured viscosity of the manufactured plastic and the calculated estimated viscosity is thus determined. This relationship is expressed as a historical value and is used in subsequent steps.

[0129] In the fifth step V, based on the pressure value D measured in step I mess , the temperature correction f(T) determined in step II and the volume flow S are used to determine the viscosity value V KF (T).

[0130] For a measurement method in which the viscosity is proportional to the pressure loss over the static mixer (eg V number), the following relationship results

[0131] [V KF (T)]=[f(T) / S]*[(D mess *d1)+d2]+d3+KF.

[0132] For measurement methods in which the viscosity is inversely proportional to the pressure loss over the static mixer (e.g. MVR), [1 / V KF (T)]=[f(T) / S]*[(D mess *d1)+d2]+d3+KF.

[0133] For which V~a*(D mess )^b form of the pressure loss D on the static mixer mess In the measurement method for determining the viscosity based on the nonlinear dependence of

[0134] [V KF (T) / a] ∧(1 / b) =[f(T) / S]*[(D mess *d1)+d2]+d3+KF.

[0135] In this case, d1, d2 and d3 are constants that depend on the plastic being produced. These constants (values) are usually initially determined by parameter adaptation between laboratory values ​​and operating data according to the least squares method without correction factors KF. The exact values ​​are therefore plant- and / or product-specific.

[0136] In the sixth step VI, the value V determined in the previous step is KF (T) and rated viscosity value V soll Here, V soll is a series of values, each value corresponding to the viscosity for a specific temperature. Thus, at the value V for temperature T1 KF The comparison is made with the nominal viscosity value for the same temperature T1. The result of the comparison is expressed as a relative value, the sign of which depends on V KF (T1) and V soll (T1) and its absolute value is equal to the absolute value of the difference.

[0137] In a seventh step VII, adjustment information RI is determined based on the comparison result from step VI. Here, the adjustment information is information about the pressure to be set in the equipment of the production facility in order to reduce V KF (T1) and V soll The difference between (T1) and (T2) is then adjusted or kept constant if the difference corresponds to a desired value. In most cases, the pressure is regulated, but the temperature and the volume flow can also be adapted.

[0138] The device is a device that measures the first pressure and the second pressure before or after the first pressure in step 1.

[0139] In an eighth step VIII, the regulation information RI from step VII is used to control and / or regulate (eg set) the device, thereby influencing the pressure in the device. The device is preferably a viscous reactor.

[0140] Figure 2 The schematic diagram shows the method for executing the Figure 1 The invention relates to a method for producing a thermoplastic material in a system 2. The system 2 comprises a static mixer 4 which is part of a production facility 6 and is configured to produce thermoplastics. Furthermore, the system 2 comprises a device for detecting pressure values, in the present case in the form of a pressure sensor 8, a storage medium, in the present case in the form of a data carrier 10, and a computing unit 12.

[0141] The respective components of the system are connected via a communication connection. Figure 2 This is schematically illustrated by means of thick dashed arrows.

[0142] When producing thermoplastics, the plastics are passed through a static mixer 4 . In the process, a pressure loss occurs between the inlet of the static mixer 4 and the outlet of the static mixer 4 .

[0143] The pressure sensor 8 is arranged to detect two pressures, for example by means of two sensors. Figure 2 In the embodiment, the pressure sensor 8 detects a first pressure D1 at the inlet of the static mixer 4 and a second pressure D2 at the outlet of the static mixer 4. The pressure sensor 8 has a calculation function to calculate the difference D mess = Processor unit of D1-D2 ( Figure 2 not shown).

[0144] The pressure sensor 8 has a communication device which is arranged to be in communication connection with the computing unit 12 and with the data carrier 10. Thus, on the one hand, the D obtained during the continuous pressure measurement mess The value is stored in the data carrier 10. On the other hand, D mess The corresponding current value of is transmitted to the calculation unit 12.

[0145] The setpoint viscosity value V is stored in the data carrier 10 soll —Each rated viscosity value V soll Corresponding to the viscosity value for a specific temperature are the temperature and volume flow S measured and transmitted from the production facility 6 by means of suitable devices (not explicitly shown here), and the actual viscosity value V measured directly in the laboratory at the specific temperature in each case labor The data carrier 10 is connected to the computing unit 12 via a bidirectional communication connection, so that information can be transmitted both from the data carrier 10 to the computing unit 12 and from the computing unit 12 to the data carrier 10 .

[0146] The computing unit 12 has a storage medium and program instructions, which are stored on the storage medium and can be executed. The program instructions are written in a common program and are respectively provided for performing calculations.

[0147] Based on the pressure value D transmitted from the pressure sensor 8 mess , the temperature T1 likewise transmitted from the data carrier 10 and the volume flow S transmitted from the data carrier 10 and the setpoint viscosity value V transmitted from the data carrier 10 soll , the calculation unit 12 performs a calculation by means of first program instructions, which calculation provides an estimated and temperature-dependent value V g (T1). In addition, the calculation unit 12 also calculates the value V transmitted from the data carrier 10 through other program instructions. labor To calculate the previously calculated value V as described above g (T1) and value V labor This difference forms a historical value which is stored in the data carrier 10 together with other historical values ​​as a correction factor KF.

[0148] The calculation unit 12 calculates the correction factor KF based on a plurality of historical values ​​and by other program instructions. Then, the calculation unit 12 calculates the correction factor KF by other program instructions and by taking into account the pressure value D transmitted from the pressure sensor 8. mess Calculate the viscosity value V corrected by the correction factor KF KF (T1). Based on V KF (T1) The calculation unit 12 determines the control information RI by means of further program instructions, taking into account the possibility of providing the control and / or regulating device 14 for setting the viscous reactor 16 on the one hand and the possibility of influencing the pressure on the other hand.

[0149] The adjustment information RI is then transmitted to a control and / or regulating device 14, which is set up to control a viscosity reactor 16. The viscosity reactor is arranged before the static mixer 4 in the production facility 6 and is set up to influence the viscous behavior of the plastic. The control and / or regulating device 14 sets the viscosity reactor 16 corresponding to the adjustment information RI. As a result, the viscous behavior of the plastic is influenced according to the adjustment information RI, so that the difference between the pressure at the inlet of the static mixer 4 and the pressure at the outlet of the static mixer 4 is changed when the plastic is later passed through the static mixer 4.

[0150] The system thus forms a regulatory loop that helps to reduce fluctuations in product quality.

[0151] The exemplary embodiments / embodiments described in this specification should be understood as being disclosed both individually and in all combinations with each other. In particular, the description of the features included in the described manner should not be understood as being necessary or important for the function of the embodiment in the present case, unless explicitly interpreted in the opposite manner. The order of the method steps described in the various flow charts in this specification is not mandatory, and alternative orders of the method steps can be thought of. These method steps can be implemented in different ways, so that it can be thought of that the method steps can be implemented in a way that software (by program instructions), hardware or a combination of the two can be implemented. Terms such as "including", "having", "including" used do not exclude other elements or steps. The phrase "at least partially" includes both the situation "partially" and the situation "completely". The phrase "and / or" should be understood as that both substitution and combination should be disclosed, that is, "A and / or B" means "(A) or (B) or (A and B)". In the context of this specification, multiple units, personnel, etc. refer to more than one unit, personnel, etc. A single device can perform the functions of multiple units or devices.

[0152] The embodiments shown and described in the drawings are only intended to explain the invention and are not intended to limit the invention.

[0153] Reference numerals list

[0154] 2 System

[0155] 4. Static mixer

[0156] 6Production Facilities

[0157] 8. Pressure sensor

[0158] 10 Data carrier

[0159] 12 computing units

[0160] 14 Control and / or regulating devices

[0161] 16 Viscous Reactor

[0162] 18 Temperature sensor.

Claims

1. A method for controlling and / or regulating a production facility configured to manufacture thermoplastics, the method being performed by at least one device, the method comprising: - detecting the pressure value in the production facility; - Determine temperature correction; - Determine volume flow; - determining an estimate of the indicative viscosity based at least in part on the detected pressure value and at least in part on the temperature dependency of the viscous behavior of the thermoplastic and on the temperature dependency of the volume flow; as well as - determining a viscosity value indicative of the viscous behavior of the thermoplastic at least partially as a function of a correction factor, wherein the correction factor is indicative of a facility state, and wherein the facility state is at least partially determined by at least one production parameter, wherein the correction factor corresponds to a result of a statistical calculation, wherein the statistical calculation is based on historical values ​​indicative of a relationship between the estimated value of the viscosity and the true viscosity, and wherein detecting a first pressure at a first position, - detecting a second pressure at a second location, and - the pressure value corresponds to the difference between the first pressure and the second pressure, and wherein the method further comprises: - comparing the viscosity value determined and indicative of the viscous behavior of the thermoplastic with a setpoint viscosity value; - determining at least one adjustment information, the at least one adjustment information being based at least in part on a result of the comparison; - outputting the determined regulation information or initiating the output of the determined regulation information, wherein the production facility can be controlled and / or regulated based on the determined regulation information; and - controlling and / or regulating the production facility at least partly as a function of the regulation information.

2. The method according to claim 1, in, The at least one production parameter indicates one or more of the following characteristic values ​​i) to iii): i) the temperature of the plastic; ii) pressure; and iii) The volume flow through the production facility.

3. The method according to claim 1 or 2, in, The historical values ​​indicate the facility status and the type of the thermoplastic.

4. The method according to any one of claims 1 to 2, in, The historical value is the result of repeatedly collecting samples and measuring the viscosity of the samples within a specific period of time and at specific time intervals.

5. The method according to any one of claims 1 to 2, in, The method forms a control loop and is run continuously or discretely at predefined time intervals during the production of the thermoplastic.

6. The method according to claim 5, further comprising: - a product change of the thermoplastic manufactured by the production facility from a first type of thermoplastic to a different type of thermoplastic, wherein the control loop continues to operate, wherein in order to determine a viscosity value indicative of the viscous behavior of the thermoplastic after the product change, the correction factor is based on historical values ​​which are at least partially indicative of the other type of thermoplastic.

7. A system for controlling and / or regulating a production facility configured to produce thermoplastics, comprising at least one device which is jointly constructed and / or configured to carry out the method according to any one of claims 1 to 6, It is characterized in that - providing a detection device for detecting the pressure value in the production facility (6), - providing a determination device for determining an estimated value indicative of the viscosity, wherein the determination of the estimated value indicative of the viscosity is based at least in part on the detected pressure value and at least in part on the temperature dependency of the viscous behavior of the thermoplastic and on the temperature dependency of the volume flow, and - providing a determination device for determining a viscosity value indicative of the viscous behavior of the thermoplastic, wherein the determination of the viscosity value indicative of the viscous behavior of the thermoplastic is at least partially based on a correction factor indicative of a facility state, and wherein the facility state is at least partially determined by at least one production parameter.

8. The system according to claim 7, It is characterized in that - the at least one device is a static mixer (4), - the detection device is arranged to detect a first pressure at a first position arranged before the static mixer and to detect a second pressure at a second position arranged after the static mixer (4), and - said pressure value corresponds to the difference between said first pressure and said second pressure.

9. The system according to claim 7 or 8, It is characterized in that An input device is provided for entering historical values ​​and / or for entering a setpoint viscosity value.

10. The system according to any one of claims 7 to 8, It is characterized in that A determination device is provided for determining at least one adjustment information (RI), wherein the determination of the at least one adjustment information is based on a comparison result between a viscosity value determined and indicative of the viscous behavior of the thermoplastic and a setpoint viscosity value, and an output device is provided for outputting the at least one adjustment information (RI) determined.

11. The system according to claim 10, It is characterized in that A regulation device is provided, which is arranged to perform a control and / or regulation of the at least one device, wherein the control and / or regulation is at least partially based on the determined at least one regulation information (RI).

12. The system according to claim 11, It is characterized in that - the system comprises a viscous reactor (16), - the viscosity reactor (16) is arranged to influence the viscosity behavior of the thermoplastic, and The regulating device is configured to control and / or regulate the viscous reactor (16).

Images