Information processor, polyester production system, information processing method, polyester production method, and, program

Abstract

To correctly predict a molecular weight, in a chemical treatment step in which a molecular weight of a polyester changes due to a chemical reaction.SOLUTION: An arithmetic unit acquires actual measured values of reaction condition variables in a chemical treatment process where the molecular weight of polyester changes due to a chemical reaction. The arithmetic unit calculates the predicted molecular weight based on the measured molecular weight and the reaction condition variables according to the elapsed time from the start of the reaction. The reaction condition variables include the amount of reaction slurry in the reaction vessel. This embodiment may be applied to an information processing apparatus, a polyester production system, an information processing method, a polyester production method, or a program.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present application relates to an information processing device, a polyester production system, an information processing method, a polyester production method, and a program.The present application relates to, for example, molecular weight control of polyester. [Background technology]

[0002] Molecular weight is an important indicator of the processing characteristics of synthetic resins. This is because molecular weight correlates with the melt flow rate (MFR) of synthetic resins. MFR is an indicator of the fluidity of resin. More specifically, MFR corresponds to the amount of resin extruded when a certain load is applied to a resin that has been melted by heating. Adjusting the molecular weight is important to produce synthetic resins with the required processing characteristics.

[0003] For example, the production process of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (P3HB3HH), a type of biodegradable polymer, involves a molecular weight adjustment step, in which the molecular weight is reduced to the desired molecular weight. P3HB3HH is a copolymer polyester of 3HB (3-hydroxybutyrate) and 3HH (3-hydroxyhexanoate). The reaction mechanism for the molecular weight reduction involves ester hydrolysis by hydroxide ions present in an alkaline environment. The molecular weight adjustment step is completed by stopping the reaction when the target molecular weight is reached.

[0004] Traditionally, the endpoint has been determined as the time when the target molecular weight is reached based on the actual molecular weight measurement. However, molecular weight measurement methods such as GPC (Gel Permeation Chromatography) require a considerable amount of analysis time (typically 1–2 hours or more) from sample collection to molecular weight determination. This analysis time is significant compared to the time required for the molecular weight adjustment process, and the number of measurements is limited. Furthermore, by the time the molecular weight measurement is obtained, the reaction has progressed beyond the time the sample was collected, so the measurement does not necessarily represent the actual molecular weight. Therefore, operators have often relied on experience and intuition to predict the endpoint based on a limited number of measurements (Figure 10). In response, molecular weight prediction using mathematical models has been investigated to determine the endpoint in real time. This is expected to stabilize the quality of polyester, which depends on the molecular weight, and reduce labor in the reaction process.

[0005] For example, the polyester production system described in Patent Document 1 acquires reaction condition information from a reactor in which a reaction accompanied by a change in molecular weight is taking place, acquires molecular weight information during the reaction at any time during the reaction, and predicts the molecular weight of the product during the reaction based on the reaction condition information, molecular weight conditions during the reaction, and related information relating the reaction condition information to molecular weight information indicating the molecular weight. The reaction condition information includes reaction temperature information, pH (hydrogen ion concentration index), and the amount of reaction promoter added.

[0006] The control system described in Patent Document 2 determines a molecular weight prediction model based on the measured molecular weight in the molecular weight adjustment process of a polymer compound and at least one production condition variable of the polymer compound production conditions, and calculates the predicted molecular weight value using the determined prediction model. The production condition variables include temperature, pH, and the type of strain of the microorganism that produces the polymer compound. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] International Publication No. 2022 / 163035 [Patent Document 2] Japanese Patent Application Publication No. 2022-182129 Summary of the Invention [Problem to be solved by the invention]

[0008] According to examples in each patent document, it is possible to obtain a predicted value of the molecular weight of a polyester during a chemical reaction accompanied by a change in molecular weight. The reaction completion time is predicted based on the obtained predicted value. However, in order to reduce the variability in the quality of the polyester obtained after the reaction, improvement of the prediction accuracy is expected.

[0009] The present application has been made in view of the above points, and one of the objects of the present application is to provide an information processing device, a polyester production system, an information processing method, a polyester production method, and a program that are capable of more accurately predicting the molecular weight in a chemical treatment process in which the molecular weight of a polyester changes due to a chemical reaction. [Means for solving the problem]

[0010] (1) The present application has been made to solve the above-mentioned problems, and one aspect of the present application is an information processing device that includes: an arithmetic unit that acquires actual measured values ​​of reaction condition variables in a chemical treatment process in which the molecular weight of a polyester changes due to a chemical reaction; and calculates a predicted value of the molecular weight according to the elapsed time from the start of the reaction based on the actual measured value of the molecular weight and the reaction condition variables, wherein the reaction condition variables include the amount of reaction suspension in a reaction vessel.

[0011] (2) Another aspect of the present invention is an information processing method in an information processing device, comprising: a step of acquiring an actual measured value of a reaction condition variable in a chemical processing process in which the molecular weight of a polyester changes due to a chemical reaction; and a calculation step of calculating a predicted value of the molecular weight according to the elapsed time from the start of the reaction based on the actual measured value of the molecular weight and the actual measured value of the reaction condition variable, wherein the reaction condition variable includes the amount of reaction suspension in a reaction vessel. [Effects of the Invention]

[0012] According to the present invention, the molecular weight can be more accurately predicted in chemical processing steps in which the molecular weight of polyester changes due to chemical reactions. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 2 is a schematic block diagram illustrating an example of the functional configuration of a control system according to the present embodiment. [Figure 2] FIG. 1 is a schematic block diagram illustrating an example of a hardware configuration of an information processing device according to an embodiment of the present invention. [Figure 3] FIG. 1 is an explanatory diagram illustrating an example of a polyester production process. [Figure 4] FIG. 1 is a diagram illustrating a polyester production facility. [Figure 5] FIG. 2 is a diagram showing an example of the change in molecular weight Mw over time in the molecular weight adjustment step. [Figure 6] FIG. 1 is an explanatory diagram for explaining an example of a molecular weight prediction method according to an embodiment of the present invention. [Figure 7] FIG. 10 is a diagram showing an example of timing for acquiring explanatory variables in a molecular weight adjustment step. [Figure 8] 1 is a table illustrating the prediction accuracy of hydroxide ion concentration. [Figure 9] 1 is a table illustrating the accuracy of molecular weight prediction. [Figure 10] FIG. 1 is a diagram illustrating the change in measured molecular weight over time. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, an embodiment of the present application will be described with reference to the drawings. First, an overview of this embodiment will be described. FIG. 1 is a schematic block diagram showing an example of the functional configuration of a control system 1 according to this embodiment. The control system 1 constitutes part of a polyester production system and is used to control a molecular weight adjustment process. The molecular weight adjustment process is one of the polyester production processes, and is a process in which the molecular weight of the polyester produced in the previous process is reduced by a chemical reaction. The following description mainly assumes that the polyester product is P3HB3HH, that the chemical reaction that changes the molecular weight of the polyester is ester hydrolysis of the polyester suspended in a reaction suspension, and that the reaction suspension is contained in an adjustment tank 72 (FIG. 4) of a production facility 70. The reaction suspension is an alkaline solution in which P3HB3HH is suspended as a solute. The following description mainly assumes that the alkaline solution is an aqueous solution containing caustic soda (NaOH: sodium hydroxide) as a solute (sometimes referred to as a "caustic soda solution" in this application), and that the reaction temperature is maintained at a constant set temperature during each molecular weight adjustment process.

[0015] The control system 1 includes an information processing device 10, a molecular weight measuring instrument 20, a process data detector 30, and a process control device 60. The information processing device 10 acquires molecular weight data from the molecular weight measuring device 20 and acquires process data from the process data detector 30. The molecular weight data is data indicating the actual measured value of the molecular weight measured by the molecular weight measuring device 20. The process data indicates the status of a chemical reaction in the production facility 70 (FIG. 4). The process data includes actual measured values ​​of reaction condition variables. The reaction condition variables are variables that are elements of the reaction conditions in a chemical reaction. The reaction condition variables also include values ​​that indicate the amount of reaction suspension in the reaction vessel.

[0016] The information processing device 10 calculates a predicted value of the molecular weight at the time elapsed since the start of the reaction (sometimes referred to herein as the "molecular weight adjustment elapsed time" or simply as "time") based on the actual measured value of the molecular weight and the actual measured values ​​of the reaction condition variables. The information processing device 10 controls the execution of the molecular weight adjustment process based on the calculated predicted value of the molecular weight. The information processing device 10 determines that the chemical reaction has stopped when the calculated predicted value reaches a predetermined target molecular weight. The information processing device 10 generates control information indicating the stop of the reaction and outputs the generated control information to the process control device 60.

[0017] The molecular weight measuring instrument 20 is an instrument that measures the molecular weight of P3HB3HH. The molecular weight measuring instrument 20 collects a small amount of reaction suspension as a sample from the adjustment tank 72 (FIG. 4) at predetermined intervals (e.g., every 1-2 hours). The molecular weight measuring instrument 20 measures the molecular weight of P3HB3HH suspended in the collected reaction suspension. The molecular weight measuring instrument 20 outputs molecular weight data indicating the measured molecular weight value to the information processing device 10. The molecular weight measuring instrument 20 may include the time when the sample to be measured was collected as the molecular weight measurement time in the molecular weight data. The molecular weight measuring instrument 20 can measure the molecular weight distribution of a suspended or dissolved polymer compound, for example, using the GPC method. The GPC method is a type of liquid chromatography.

[0018] The molecular weight measuring instrument 20 determines, for example, the weight-average molecular weight (Mw) as a representative value of the determined molecular weight distribution. The weight-average molecular weight corresponds to a weighted average of the molecular weights used as weighting coefficients proportional to the molecular weights of the components contained in the sample. In this application, the weight-average molecular weight is primarily used as a representative value of the molecular weight distribution, and the weight-average molecular weight may also be simply referred to as "molecular weight."

[0019] The process data detector 30 acquires process data from the production facility 70 (FIG. 4). The process data includes reaction condition variables of a chemical reaction in the production facility 70 (FIG. 4). The reaction condition variables may include an index value indicating the reaction state of the chemical reaction and an index value indicating the execution environment of the chemical reaction. The reaction condition variables include, for example, the volume of the reaction suspension, the flow rate of the alkaline solution, and pH. The volume of the reaction suspension is the volume of the reaction suspension contained in the adjustment tank 72 (FIG. 4). The flow rate of the alkaline solution corresponds to the flow rate of the alkaline solution flowing into the adjustment tank 72. The pH is the pH of the reaction suspension contained in the adjustment tank 72. The process data detector 30 outputs the acquired process data to the information processing device 10. The process data detector 30 is configured to include, for example, an input / output interface.

[0020] The process control device 60 controls the chemical reaction process in the molecular weight adjustment step. The process control device 60 controls the operation of the production equipment 70 (FIG. 4) so ​​that the actual measured values ​​indicating the reaction state or execution environment are closer to the target set values. The process control device 60 controls a controller provided in the production facility 70 so that the actual measured pH value, actual measured temperature value, and actual measured caustic flow rate value notified from the production facility 70 approximate the set pH value, set temperature value, and set caustic flow rate value, respectively. The caustic flow rate is the flow rate of the caustic soda solution flowing into the adjustment tank 72 (FIG. 4), i.e., corresponds to an example of the alkaline solution flow rate mentioned above. The process control device 60 can use known control techniques such as PI control and PID control.

[0021] Prior to the execution of the molecular weight adjustment step, various set values ​​that provide reaction conditions are preset in the process control device 60. For example, initial values ​​for pH, temperature, and caustic flow rate are set in the process control device 60. When control information indicating the set value of the reaction condition variable is input from the information processing device 10, the already set set value is updated to the set value indicated by the control information. When control information indicating reaction termination is input from the information processing device 10, hydrolysis in the adjustment tank 72 is suppressed and the molecular weight adjustment process is terminated. When the input control information includes a set value for the reaction condition variable, the process control device 60 updates the already set value to the set value instructed by the control information.

[0022] (Information processing device) Next, a description will be given of an example of the functional configuration of the information processing device 10. The information processing device 10 includes a processing unit 120 and a storage unit 170. The calculation processing unit 120 includes an input data processing unit 130 , a molecular weight calculation unit 140 , and a control information notification unit 150 . Various types of data are stored in the storage unit 170. The data stored in the storage unit 170 includes data acquired by the arithmetic processing unit 120, data used by the arithmetic processing unit 120, and the like.

[0023] The input data processing unit 130 acquires molecular weight data from the molecular weight measuring instrument 20 and acquires process data from the process data detector 30. Each time the input data processing unit 130 acquires molecular weight data, it associates the acquired molecular weight data with the time at that time and stores the data in the memory unit 170. Each time the input data processing unit 130 acquires process data, it may associate the acquired process data with the time at that time and store the data in the memory unit 170. The memory unit 170 accumulates the process data and molecular weight data at each time. The accumulated data is formed as log information. The input data processing unit 130 outputs newly input molecular weight data and process data to the molecular weight calculation unit 140.

[0024] The molecular weight calculation unit 140 calculates a predicted molecular weight value according to the elapsed time from the start of the reaction based on the actual molecular weight value indicated by the molecular weight data input from the input data processing unit 130 and the reaction condition variables indicated by the process data input from the input data processing unit 130. The molecular weight calculation unit 140 includes a hydroxide ion concentration calculation unit 142 , a reaction rate variable calculation unit 144 , a molecular weight prediction unit 146 , and a reaction condition setting unit 148 .

[0025] The hydroxide ion concentration calculation unit 142 calculates the hydroxide ion concentration [OH - Here, based on the fact that the product of pH and hydroxide ion concentration is constant at a constant temperature, the reaction rate variable calculation unit 144 converts the measured pH value indicated in the process data into a converted value of hydroxide ion concentration [OH-]. The hydroxide ion concentration calculation unit 142 calculates the hydroxide ion concentration [OH-] at the predicted time t using a predetermined regression analysis model (sometimes referred to as a "first model" in this application) based on the alkaline solution flow rate, the converted value of hydroxide ion concentration [OH-], and the reaction suspension volume up to the most recent measurement time indicated in the process data. - The hydroxide ion concentration calculation unit 142 outputs the calculated estimated value of the hydroxide ion concentration [OH-] to the molecular weight prediction unit 146. The prediction time t is the time of the molecular weight to be predicted. The prediction time t is a time later than the latest molecular weight measurement time t-1.

[0026] The reaction rate variable calculation unit 144 calculates the actual molecular weight Mw indicated in the molecular weight data at the latest molecular weight measurement time t-1 input from the input data processing unit 130. t-1 Based on the pH measurement value shown in the process data, the reaction rate variable K at the molecular weight measurement time t-1 t-1 The reaction rate variable calculation unit 144 calculates the calculated reaction rate variable K t-1 is output to the molecular weight prediction unit 146.

[0027] The molecular weight prediction unit 146 calculates the actual molecular weight Mw indicated in the molecular weight data at the latest molecular weight measurement time t-1 input from the input data processing unit 130. t-1 , the hydroxide ion concentration [OH - ], and the reaction rate variable K input from the reaction rate variable calculation unit 144t-1 Predict the molecular weight Mw at time t based on t The molecular weight prediction unit 146 calculates the calculated molecular weight Mw t to the control information notification unit 150.

[0028] The reaction condition setting unit 148 calculates the actual molecular weight Mw indicated in the molecular weight data at the latest molecular weight measurement time t-1 input from the input data processing unit 130. t-1 The reaction condition setting unit 148 determines the set values ​​of the reaction conditions using a reaction condition setting model based on the above. The reaction condition setting model may, for example, be set to the relationship between the reaction conditions and the actually measured molecular weight in a molecular weight adjustment step that was previously performed. The reaction condition setting unit 148 determines, for example, a temperature set value, a pH set value, and a caustic flow rate set value. The reaction condition setting unit 148 outputs the determined set values ​​of the reaction conditions to the control information notification unit 150.

[0029] The control information notification unit 150 outputs control information for controlling the molecular weight adjustment process to the process control device 60 based on the actually measured or estimated molecular weight. The control information notification unit 150 outputs control information indicating the set values ​​of the reaction conditions input from the reaction condition setting unit 148 to the process control device 60 during the execution of the molecular weight adjustment step. The control information notification unit 150 receives the molecular weight Mw at the predicted time t from the molecular weight prediction unit 146. t The control information notification unit 150 receives the molecular weight Mw t is the predetermined target molecular weight Mw end The time when the reaction ends is t end The control information notification unit 150 determines whether the current time t is the response end time t end When it is determined that the temperature has reached the predetermined value, the control information notification unit 150 generates notification information indicating the stop of the chemical reaction. The control information notification unit 150 outputs the generated notification information to the process control device 60.

[0030] Next, an example of the hardware configuration of the information processing device 10 will be described. The information processing device 10 may be configured to include dedicated hardware or a general-purpose computer system. Fig. 2 is a schematic block diagram showing an example of the hardware configuration of the information processing device 10 according to this embodiment. The example of Fig. 2 is based on the premise that the information processing device 10 is configured to include a general-purpose computer system. The information processing device 10 is a computer including a processor 102, an input unit 108, an output unit 110, a ROM 112, a RAM 114, an auxiliary storage unit 116, and an interface unit 118.

[0031] The processor 102 reads a predetermined program stored in advance in the ROM 112 and executes processing instructed by various instructions written in the read program. In this application, executing processing instructed by instructions written in a program may be referred to as "executing a program" or "running a program." The processor 102 includes, for example, a CPU (Central Processing Unit). The processor 102 executes the program and cooperates with other hardware, for example, the ROM 112, the RAM 114, the auxiliary storage unit 116, and the interface unit 118, to realize the functions of the arithmetic processing unit 120.

[0032] The input unit 108 receives a user operation and generates an operation signal indicated by the received operation. The input unit 108 outputs the generated operation signal to the processor 102. The input unit 108 includes components such as a touch sensor, a keyboard, and a mouse. The output unit 110 outputs output information indicated by various output data input from the processor 102. The output unit 110 includes, for example, a display for presenting an image.

[0033] The ROM (Read Only Memory) 112 is a storage medium that permanently stores various data used by the processor 102. RAM (Random Access Memory) 114 is a storage medium that temporarily stores various data (parameters, etc.) used in the operation of processor 102 and various data acquired by processor 102. RAM 114 is used as a working area for processor 102. The auxiliary storage unit 116 is a storage medium that permanently stores various data acquired by the processor 102 and various data used by the processor 102. The auxiliary storage unit 116 may be configured to include, for example, either an SSD (Solid State Drive), an HDD (Hard Disk Drive), or the like, or a predetermined combination thereof.

[0034] The interface unit 118 is connected to other devices wirelessly or via a wire so as to be able to send and receive various types of data. The interface unit 118 may be connected to other devices using a communication network. The interface unit 118 may be configured to include, for example, an input / output interface, a communication interface, or a combination thereof.

[0035] (Production process) Next, the polyester production process will be described using the P3HB3HH production process as an example. FIG. 3 is an explanatory diagram illustrating an example of the polyester production process. The P3HB3HH production process includes a production process, a purification process, and a post-treatment process, and is carried out in a production facility 70 (FIG. 4). The production process includes a culture process and an inactivation process. The purification process includes a cell membrane hydrolysis process (Lys treatment), a protein hydrolysis process (Alc treatment), a molecular weight adjustment process, a solubilization process (SDS treatment), and a separation process. The post-treatment process includes a membrane concentration process, a pH adjustment process, and a drying process.

[0036] The culturing step is a process of culturing microorganisms. The culturing target is a bacterial species or strain that synthesizes polymeric compounds in the process of metabolizing organic matter. Examples of such bacterial species or strains include Ralstonia eutropha, Candida maltosa, and Cupriavidus necator. These bacterial species or strains metabolize natural organic materials such as palm oil and fructose to synthesize P3HB3HH. P3HB3HH is a type of polyhydroxyalkanoate (PHA), which is biodegradable and has a low environmental impact. In the culturing step, a bacterial species or strain that can produce P3HB3HH with a weight-average molecular weight of approximately 1 to 2 million is used.

[0037] The inactivation process is a process for inactivating the activity of cultured microorganisms. For example, the cultured bacteria are heated during the inactivation process. During the inactivation process, some of the P3HB3HH retained within the bacterial cells may undergo a depolymerization reaction due to heat, resulting in a decrease in molecular weight.

[0038] The cell membrane hydrolysis treatment step is a step of hydrolyzing the cell membrane of a microorganism. The cell membrane contains phospholipids as a main component. In the cell membrane hydrolysis treatment step, a hydrolytic enzyme for phospholipids is added to a solution of inactivated microorganisms, and hydrolysis of the cell membrane is carried out. For example, lysine, lipase, etc. can be used as the hydrolytic enzyme. In the cell membrane hydrolysis treatment step, the cell membrane is destroyed, and various components within the cell are eluted into the solution, and the eluted components include P3HB3HH.

[0039] The protein hydrolysis process is a process for hydrolyzing the eluted protein. In the protein hydrolysis process, a protein hydrolase is added to carry out protein hydrolysis. Examples of hydrolase that can be used include serine alcohol and secondary threonine alcohol. In the cell membrane hydrolysis process and the protein hydrolysis process, some of the P3HB3HH eluted into the solution may undergo a depolymerization reaction, resulting in a decrease in molecular weight. The process then proceeds to the molecular weight adjustment process. After the molecular weight adjustment process is completed, the process proceeds to the solubilization process.

[0040] The solubilization step is a step of solubilizing other bacterial components and lipids contained in the suspension of molecular weight-adjusted P3HB3HH. In the solubilization step, a surfactant with a denaturing effect is added to the suspension of molecular weight-adjusted P3HB3HH. For example, sodium dodecyl sulfate (SDS) can be used as the surfactant. The separation step is a step of separating P3HB3HH from the suspension. In the separation step, for example, the suspension is centrifuged to extract P3HB3HH as a major component.

[0041] The membrane concentration process is a process in which a concentrated suspension and a dilute suspension of extracted P3HB3HH are separated using a reverse osmosis membrane, and the concentrated suspension is further concentrated by applying a pressure higher than the osmotic pressure to the concentrated suspension. The pH adjustment step is a step in which a pH adjuster is added to the concentrated suspension to neutralize the pH of the suspension. The drying step is a step in which the neutralized suspension is dried to extract P3HB3HH.

[0042] Next, the molecular weight adjustment step will be described. The molecular weight adjustment step is a step of adjusting the P3HB3HH suspended in the reaction suspension to a predetermined target molecular weight. The target molecular weight varies depending on the application, but is typically about 200,000 to 600,000. The molecular weight adjustment step involves irreversible ester hydrolysis by the P3HB3HH suspended in the reaction suspension and hydroxide ions. In ester hydrolysis, hydroxide ions (OH) are added to the ester bonds between the monomers constituting one P3HB3HH. - The polyester reacts with the carboxylic acid (R-COOH) and breaks down into a carboxylic acid molecule (R-COOH) having a terminal carboxyl group and a molecule (R-OH) having a hydroxyl group. The molecular weight adjustment step in the polyester production process does not necessarily have to be performed between the protein hydrolysis treatment step and the solubilization treatment step. The molecular weight adjustment step may be performed after the inactivation treatment and before the protein hydrolysis treatment step.

[0043] The molecular weight adjustment process is carried out in an adjustment tank 72. The adjustment tank 72 constitutes a part of the P3HB3HH production facility 70. As shown in FIG. 4, the adjustment tank 72 contains a reaction suspension, and a caustic soda solution is injected into the adjustment tank 72 during the chemical reaction. In the adjustment tank 72, the solution is stirred using an agitator 74 so that the pH and temperature of the solution become uniform. The adjustment tank 72 is equipped with a pH sensor 722, a temperature sensor 724, a flow rate sensor 726, and a level sensor 728. As described above, the pH sensor 722 and the temperature sensor 724 measure the pH and temperature of the reaction suspension, respectively. The flow rate sensor 726 is installed in the caustic soda solution conduit. The flow rate sensor 726 measures the flow rate of caustic soda injected into the adjustment tank 72 as the caustic flow rate. The level sensor 728 measures the liquid level of the reaction suspension contained in the adjustment tank 72 and converts the measured level into the volume of the reaction suspension based on a preset correspondence between the height and the volume of the reaction suspension. The measured pH value, temperature value, caustic flow rate, and volume of the reaction suspension are notified to the process control device 60. The notified pH value, temperature value, caustic flow rate, and volume of the reaction suspension are used by the process control device 60 to adjust the pH, temperature, and caustic flow rate of the reaction suspension contained in the adjustment tank 72.

[0044] FIG. 5 shows an example of the change in molecular weight Mw over time in the molecular weight adjustment step. The molecular weight at the start time of the molecular weight adjustment step is Mw0. As the depolymerization reaction progresses, the molecular weight gradually decreases. However, a certain amount of time is required for analysis from the start of one measurement until the actual measured molecular weight is obtained. Since the timing of molecular weight measurement is discrete, the actual measured value of the molecular weight at any given time point is not necessarily obtained. Furthermore, when the molecular weight at a certain molecular weight measurement time is obtained, the molecular weight will further decrease as the reaction progresses within the analysis time. According to this embodiment, the molecular weight at any time point after the last molecular weight measurement time is predicted. Therefore, the molecular weight Mw of the reaction suspension is set to the target molecular weight Mw end The time when the reaction ends is t end It can be quantitatively determined as follows.

[0045] Next, the molecular weight prediction method according to this embodiment will be described in more detail. Fig. 6 is an explanatory diagram for explaining an example of the molecular weight prediction method according to this embodiment. The hydroxide ion concentration calculation unit 142 calculates the hydroxide ion concentration [OH - ] is calculated. The converted value of hydroxide ion concentration is converted from the measured pH value indicated in the process data. The alkaline solution flow rate and the reaction suspension volume are notified in the process data. The hydroxide ion concentration calculation unit 142 identifies the parameters of the first model using a linear regression method such as multiple regression or partial least squares regression (PLS).

[0046] The reaction rate variable calculation unit 144 calculates the most recent n (n is an integer of 2 or more, for example, 4) measured molecular weights Mw t-n ~Mw t-1 and the measured pH value at each molecular weight measurement time t-n ~pH t-1 is used as an explanatory variable, and the reaction rate variable K t-1 Calculate.

[0047] The reaction rate variable calculation unit 144 calculates n-1 actual molecular weights Mw up to the molecular weight measurement time t-1. t-n-1 ~Mw t-1 and predicted molecular weight Mw_calc t-n-1 ~Mw_calc t-1 The parameters of the reaction rate equation for calculating the reaction rate variable from the molecular weight and pH at each time are searched for (minimizing the sum of squared residuals) so that the sum of squared residuals with ' is as small as possible. t-n-1 ~Mw_calc t-1 As such, the molecular weight already calculated using formula (1) can be applied.

[0048] The reaction rate variable calculation unit 144 applies the searched parameters and calculates the molecular weight measurement time tn-1 Reaction rate variable K from the molecular weight measurement time t t-n-1 ~K t The second model is a predetermined function for estimating the reaction rate variable at any time. For example, a simple regression equation showing the change over time from the reaction rate variable at a certain point in time is used as the second model. The reaction rate variable calculation unit 144 calculates the calculated reaction rate variable K t is output to the molecular weight prediction unit 146.

[0049] The molecular weight prediction unit 146 calculates the actual molecular weight Mw at the molecular weight measurement time t-1. t-1 , hydroxide ion concentration [OH - ], and the reaction rate variable K at the molecular weight measurement time t t Based on this, the predicted molecular weight Mw at the predicted time t is calculated using equation (1). t is calculated as the objective variable. In formula (1), [OH - ] t is the hydroxide ion concentration [OH - ] is shown as the average value.

[0050]

number

[0051] As mentioned above, since measuring and analyzing molecular weights takes a considerable amount of time, it is not possible to obtain the actual molecular weight at any measurement time. In addition, the actual measured value of the reaction rate variable is determined based on the actual molecular weight at each of multiple molecular weight measurement times. In other words, the latest actual measured value of the reaction rate variable is determined based on the actual molecular weight at at least the second most recent molecular weight measurement time and the latest molecular weight measurement time. In contrast, the process data indicating the actual pH value or the hydroxide ion concentration [OH - ] can be obtained in real time. Therefore, according to the above method, regardless of the difference in the time when the latest explanatory variables were obtained, the predicted value Mw of the molecular weight at any prediction time t after the latest molecular weight prediction time t-1 can be obtained.t The hydroxide ion concentration [OH - ] is determined based on the alkaline solution flow rate, so hydrolysis control based on the caustic flow rate is taken into consideration. Therefore, the hydroxide ion concentration [OH - ], a more stable predicted molecular weight value can be calculated.

[0052] Next, the hydroxide ion concentration [OH - 8 shows the prediction accuracy of the hydroxide ion concentration [OH - ] is used as explanatory variables, and corresponds to a comparative example in which the converted value of hydroxide ion concentration and the alkaline solution flow rate are used without using the reaction suspension volume. Pattern II corresponds to this embodiment in which the converted value of hydroxide ion concentration, the alkaline solution flow rate, and the reaction suspension volume are all used as described above. As an index of prediction accuracy, R 2 The mean absolute error (R) was calculated. 2 The R value indicates the correlation between the actual measured value and the predicted value in the lot. The mean absolute error corresponds to the average value within the lot for the absolute value of the difference between the actual measured value and the predicted value. Pattern II has a higher R value than Pattern I. 2 This means that by using the reaction suspension volume as in Pattern II, the hydroxide ion concentration [OH - ] shows that the prediction accuracy is improved.

[0053] Next, the prediction accuracy of the molecular weight according to this embodiment will be described. Fig. 9 illustrates the prediction accuracy of the molecular weight of one lot in the molecular weight adjustment process of P3HB3HH for each of Patterns I and II. Pattern I uses the converted value of hydroxide ion concentration and the hydroxide ion concentration [OH -] corresponds to a comparative example in which the molecular weight is predicted using the converted value of the hydroxide ion concentration, the alkaline solution flow rate, and the hydroxide ion concentration [OH - This corresponds to the present embodiment, in which the molecular weight is predicted using the formula

[0046] . FIG. 9 shows the mean absolute error of molecular weight for each of the elapsed times of molecular weight adjustment of 7 hours, 8 hours, 9 hours, and 10 hours. According to FIG. 9, the mean absolute error is lower for Pattern II than for Pattern I for each elapsed time of molecular weight adjustment. This indicates that the accuracy of molecular weight prediction can be improved by using the volume of reaction suspension as in Pattern II.

[0054] As described above, the information processing device 10 according to this embodiment includes a calculation unit (e.g., molecular weight calculation unit 140) that acquires actual measured values ​​of reaction condition variables in a chemical treatment process (e.g., a molecular weight adjustment process) in which the molecular weight of a polyester (e.g., P3HB3HH) is changed by a chemical reaction (e.g., hydrolysis), and calculates a predicted value of the molecular weight according to the elapsed time from the start of the reaction based on the actual measured value of the molecular weight (e.g., the measured molecular weight Mw) and the reaction condition variables. The reaction condition variables include the amount of reaction suspension in a reaction vessel (e.g., the adjustment tank 72). According to this configuration, by including the reaction suspension volume in the reaction condition variables, it is possible to more accurately predict the molecular weight at any time that is adjusted by the chemical reaction.

[0055] The calculation unit calculates the hydroxide ion concentration (e.g., [OH - ]) is calculated, and the reaction rate variable (e.g., K) is calculated based on the actual measured molecular weight values ​​(e.g., the most recent n measured molecular weights Mw) and the converted hydroxide ion concentration values ​​within a certain period up to the present time. t-1 ) and use the actual molecular weight, estimated hydroxide ion concentration, and reaction rate variables to calculate a predicted molecular weight. According to this configuration, it is possible to obtain a predicted value of molecular weight at any prediction time, regardless of the timing or frequency of obtaining the actual measured value of molecular weight, the reaction rate variable, and the converted value of hydroxide ion concentration.

[0056] The calculation unit may calculate an estimated hydroxide ion concentration based on the alkaline solution flow rate (e.g., caustic flow rate) introduced into the reaction vessel, the amount of reaction suspension in the reaction vessel, and the converted value of the hydroxide ion concentration in the reaction vessel. The set value of the alkaline solution flow rate may also be determined based on the actual measured value of the molecular weight. According to this configuration, the hydroxide ion concentration in the reaction vessel can be estimated with higher reliability by taking into account not only the converted value of the hydroxide ion concentration but also the reaction control in the reaction vessel based on the alkaline solution flow rate and the amount of reaction suspension.

[0057] The calculation unit may calculate the time when the predicted molecular weight value reaches a predetermined target value (for example, a target molecular weight) as the reaction end time. The information processing device 10 may also include a control information notification unit 150 that instructs the suppression of the chemical reaction in the reaction vessel at the reaction end time. That is, the polyester production system according to this embodiment may be configured to execute a polyester production method that suppresses the chemical reaction when the predicted value of the molecular weight reaches a predetermined target molecular weight. According to this configuration, a polyester having a molecular weight close to a target value can be obtained based on a highly accurately predicted molecular weight value, thereby suppressing the difference in physical properties of the produced polyester due to the molecular weight.

[0058] The embodiments of the present invention have been described in detail above with reference to the drawings, but the specific configuration is not limited to that described above, and various design changes can be made within the scope of the gist of the present invention.

[0059] For example, the control system S1 may be configured as a part of a production system including a production facility 70 that performs a production process for a polyester whose molecular weight is to be adjusted. The production facility 70 includes an adjustment tank 72 in which the molecular weight adjustment process is performed. The information processing device 10 in the above-described embodiment may be configured integrally with any of the molecular weight measuring device 20, the process data detector 30, and the process control device 60, or may be configured separately. The information processing device 10 may also be configured independent of the control system S1. The information processing device 10 may be connected to the production facility 70 wirelessly or via a wire so as to be able to send and receive various data.

[0060] In the above examples, the polyester to be adjusted in molecular weight is primarily P3HB3HH, a copolymer of 3HB and 3HH, but this is not limiting. The polyester to be adjusted in molecular weight may also be a poly(3-hydroxyalkanoate) (P3HA: poly(3-hydroxyalkanoate)) other than P3HB3HH, or even a polymer containing 3HB as a monomer. Examples of such substances include poly(3-hydroxybutyrate) (P3HB: poly(3-hydroxybutyrate)) and poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P3HB4HB: (3-hydroxybutyrate-co-4-hydroxybutyrate)). The alkaline solution constituting the reaction suspension is not limited to an aqueous solution containing dissolved caustic soda, as long as it is an aqueous solution capable of carrying out ester hydrolysis of polyester. For example, it may be an aqueous solution containing dissolved caustic potassium. [Explanation of symbols]

[0061] S1...control system, 10...information processing device, 20...molecular weight measuring device, 30...process data detector, 60...process control device, 120...arithmetic processing unit, 130...input data processing unit, 140...molecular weight calculation unit, 142...hydroxide ion concentration calculation unit, 144...reaction rate variable calculation unit, 146...molecular weight prediction unit, 148...reaction condition setting unit, 150...control information notification unit, 170...storage unit

Claims

1. Obtaining actual measured values ​​of reaction condition variables in a chemical treatment process in which the molecular weight of polyester changes due to a chemical reaction; Based on the measured molecular weight and the reaction condition variables, a calculation unit that calculates a predicted value of the molecular weight according to the elapsed time from the start of the reaction, The reaction condition variables include the volume of the reaction suspension in the reaction vessel. Information processing device.

2. The calculation unit calculating an estimate of the hydroxide ion concentration in the reaction vessel based on the reaction condition variables; Calculating a reaction rate variable based on the actual measured value of the molecular weight and the converted value of the hydroxide ion concentration within a certain period up to the present time; Calculating the predicted molecular weight using the measured molecular weight, the estimated hydroxide ion concentration, and the reaction rate variable. The information processing device according to claim 1 .

3. The calculation unit The estimated hydroxide ion concentration is calculated based on the flow rate of the alkaline solution introduced into the reaction vessel, the amount of the reaction suspension, and the converted value of the hydroxide ion concentration in the reaction vessel. The information processing device according to claim 2 .

4. The calculation unit The set value of the alkaline solution flow rate is determined based on the measured value of the molecular weight. The information processing device according to claim 3 .

5. The calculation unit The time when the predicted molecular weight value reaches a predetermined target value is calculated as the reaction end time. The information processing device according to claim 2 .

6. At the reaction completion time, a control information notification unit that instructs the suppression of the chemical reaction in the reaction vessel. The information processing device according to claim 5 .

7. To the computer A program for causing the information processing device according to claim 1 to function.

8. The information processing device according to claim 1 ; The reaction vessel Polyester production system.

9. An information processing method in an information processing device, acquiring actual measurements of reaction condition variables in a chemical treatment process in which a chemical reaction changes the molecular weight of the polyester; Based on the measured value of the molecular weight and the measured value of the reaction condition variable, a calculation step of calculating a predicted value of the molecular weight according to the elapsed time from the start of the reaction, The reaction condition variables include the volume of the reaction suspension in the reaction vessel. Information processing methods.

10. Execute the information processing method according to claim 9, when the predicted molecular weight reaches a predetermined target value; Suppress the chemical reaction Polyester production methods.

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