WO2023157700A1

WO2023157700A1 - Method for supporting air treatment in multitubular reactor, and device

Info

Publication number: WO2023157700A1
Application number: PCT/JP2023/003849
Authority: WO
Inventors: 成喜奥村; 智志河村; 佑太中澤
Original assignee: 日本化薬株式会社
Priority date: 2022-02-18
Filing date: 2023-02-06
Publication date: 2023-08-24

Abstract

This method for supporting air treatment in a multitubular reactor including a plurality of reaction tubes for producing at least one of unsaturated carboxylic acid and unsaturated aldehyde by means of an oxidation reaction using a catalyst or a conjugated diene by means of an oxidative dehydrogenation reaction causes a computer device to execute: an acquisition step for acquiring information pertaining to a gas flowing into and out of the reactor as reaction information; and an output step for outputting assistance information for assisting in the air treatment by numerically processing the reaction information.

Description

Method and apparatus for supporting air handling in multi-tubular reactors

The present invention relates to methods and apparatus for supporting air handling in multitubular reactors.

Patent Document 1 discloses a method of treating with a gas mixture in an oxidation reaction for producing unsaturated aldehydes, unsaturated carboxylic acids, and conjugated dienes using a multitubular reactor. The purpose of treatment with a gas mixture is various, for example, removing coke-like carbon compounds accumulated inside and outside the catalyst due to a long-term reaction, regenerating the catalyst in a reduced state, and reoxidizing the catalyst. Performance improvement by processing and the like can be mentioned. The gas to be used is appropriately selected depending on the purpose, but air containing no hydrocarbons and gas containing molecular oxygen are usually used as the inlet gas. As another inlet gas, water vapor may be introduced to improve the effectiveness of air treatment. Further, a treatment (hereinafter referred to as air treatment) in which part or all of each inlet gas flow rate, reaction bath temperature and reactor pressure are appropriately set is generally used.

WO2005/047224

On the other hand, if the catalyst used in the oxidation reaction is subjected to high-temperature air treatment, the combustion of coke-like carbon compounds and the reoxidation of the catalyst may cause sudden heat generation and damage to the catalyst. A temperature profile setting is required. Furthermore, in the case of a catalyst mainly composed of Mo (molybdenum), W (tungsten), and P (phosphorus), these components may disappear due to air treatment. In addition, in an actual plant, since the operation of the plant is stopped during air treatment, it is not preferable from the viewpoint of the productivity of the plant that the air treatment takes a long time. Therefore, in order to complete the air treatment in a short time, it is important to appropriately determine when the air treatment is finished. However, this determination is often made empirically, and it is by no means easy without a skilled technician. In other words, in the oxidation reaction that produces unsaturated aldehydes, unsaturated carboxylic acids, and conjugated dienes using a multitubular reactor, the air treatment work in the actual plant is, as described above, long-term use of the catalyst, improvement of stable operation, Although this work is necessary from the viewpoint of improving the performance of the catalyst, there has been a demand for a method that can be carried out efficiently in a shorter period of time.
The present invention provides conditions for setting and ending each treatment step during air treatment in a multi-tubular reactor containing a plurality of reaction tubes for producing unsaturated aldehydes, unsaturated carboxylic acids, or conjugated dienes by an oxidation reaction using a catalyst. The task is to facilitate the identification of

Means for solving the above problems are listed below.
1)
A method for supporting air treatment of a shell-and-tube reactor comprising a plurality of reactor tubes producing unsaturated aldehydes and/or unsaturated carboxylic acids by catalytic oxidation or conjugated dienes by oxidative dehydrogenation. and
computer equipment,
an obtaining step of obtaining, as reaction information, information on gases flowing into and out of the reactor;
and an output step of numerically processing the reaction information to output assistance information for assisting the air treatment.
2)
the reaction information includes information about gas composition at the outlet of the shell-and-tube reactor;
The support information includes at least one of information on the integrated carbon throughput of the multi-tubular reactor or information on the carbon throughput per unit time of the multi-tubular reactor,
A method of supporting air handling as described in 1) above.
3)
the reaction information includes information about gas composition at the outlet of the shell-and-tube reactor;
The support information includes at least one of information on the accumulated oxygen absorption amount of the multi-tubular reactor and information on the oxygen absorption amount per unit time of the multi-tubular reactor.
A method of supporting air handling as described in 1) above.
4)
the reaction information includes information about the temperature distribution in the reaction tubes of the multi-tubular reactor;
The support information includes information about changes in the pipe temperature distribution over time during the air treatment.
A method of supporting air handling according to any one of 1) to 3) above.
5)
to the computer device,
Any one of 1) to 4) above, further comprising executing an output step of outputting comparison information between the support information and support information output in the past air treatment in the multitubular reactor. Air handling support method as described in .
6)
Apparatus to support air treatment in multi-tube reactors containing multiple reaction tubes producing unsaturated aldehydes and/or unsaturated carboxylic acids by catalytic oxidation or conjugated dienes by oxidative dehydrogenation. and
The device has an acquisition unit and an output unit,
The acquisition unit is configured to acquire information about gas flowing into and out of the reactor as reaction information,
The output unit is configured to output support information for supporting the air treatment by numerically processing the reaction information.
A device that supports air handling.

According to the present invention, it is possible to support the setting of conditions for each treatment step in the air treatment process of a multi-tubular reactor and the determination of completion.

FIG. 4 is a schematic plan view showing a multi-tubular reactor according to an embodiment, and a diagram showing an example in which the multi-tubular reactor is spatially divided into three sections. FIG. 3 is a schematic diagram showing layers of catalyst packed in one reaction tube. Fig. 3 shows a flow chart of a method according to an embodiment; 2 is a graph plotting the concentration of carbon dioxide contained in the reactor outlet gas versus air treatment time, based on the data illustrated in Table 1; 2 is a graph plotting carbon throughput per unit time versus air treatment time based on the data illustrated in Table 1; 2 is a graph plotting integrated carbon throughput versus air treatment time based on the data illustrated in Table 1; 2 is a graph plotting catalyst peak temperature versus air treatment time based on the data illustrated in Table 1;

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The method according to the present embodiment is a method for supporting air treatment of a multi-tube reactor containing multiple reaction tubes for producing unsaturated aldehydes, unsaturated carboxylic acids, or conjugated dienes by catalytic oxidation reactions. . The method comprises a step of acquiring analysis information of gas inflow and outflow of the multi-tubular reactor, and supporting information for assisting air treatment of the multi-tubular reactor by statistically processing the analysis information in a computer device. and an output step of outputting.

The computer device used in this embodiment is a computer device comprising a microprocessor such as a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), a memory such as a flash memory, and a bus. The computer device may execute at least part of the method according to the present embodiment by means of a program recorded in a memory included in the computer device or in a recording medium readable by the computer device. The present embodiment also presents a program for causing a computer device to execute at least part of a method described later, and a recording medium recording the program. Note that the computer device that can be used in this embodiment is not limited to this aspect. For example, a cloud computing system in which computer resources are connected via a network may be used as the computer device used in the method of the present disclosure.

FIG. 1 is a schematic plan view showing a multi-tubular reactor 10 to be subjected to the method according to this embodiment. The shell-and-tube reactor 10 shown in FIG. 1 is cylindrical. FIG. 1 shows three compartments A, B, and C that are divided every 120° with respect to the center of the multi-tubular reactor 10 in plan view. A portion of the plurality of reaction tubes 20 included in section A is shown surrounded by a dashed line. A plurality of reaction tubes 20 are also provided outside the dashed line in section A and in sections B and C, but illustration of these reaction tubes 20 is omitted. The multitubular reactor 10 produces at least one of the target unsaturated aldehyde, unsaturated carboxylic acid, and conjugated diene depending on the catalyst to be filled, the raw material to be supplied, and the like. Examples of unsaturated aldehydes and unsaturated carboxylic acids to be produced include acrolein and acrylic acid, methacrolein and methacrylic acid, and examples of conjugated dienes include 1,3-butadiene and isoprene. Each of the plurality of reaction tubes 20 included in the multitubular reactor 10 is filled with a catalyst. In addition, in FIG. 1, as an example, the sections are divided in the direction of the rotation axis in the plane of the multi-tubular reactor 10, but other arbitrary division methods, such as the radial direction, the radial direction and the direction of the rotation axis, and further A method of partitioning with arbitrary polygons is also included in the present invention. Since the air treatment support method of the present invention is a method that uses analytical information on the inflow and outflow gases of the multi-tubular reactor, the arrangement of the reaction tubes in the reactor does not necessarily have to be divided into a plurality of compartments. do not have.

The catalyst is generally packed in the reaction tube 20 in a shell-and-tube reactor so that different catalyst species form two or more layers. FIG. 2 is a schematic diagram showing a catalyst layer packed in one reaction tube 20. As shown in FIG. In the example shown in FIG. 2, four layers of catalyst layers 22, 24, 26, 28 packed on the support ring 30 are shown. The activity of the plurality of layers is different from each other. For example, the activity of the fourth catalyst layer 28 is low in the order of filling on the inlet side where the raw material is supplied, and the activity increases toward the outlet side (support ring 30 side). (Counting from the inlet side, activity of the fourth catalyst layer 28<activity of the third catalyst layer 26<activity of the second catalyst layer 24<activity of the first catalyst layer 22) may be At least one of the target unsaturated aldehyde, unsaturated carboxylic acid, and conjugated diene is produced by supplying raw materials to a reaction tube 20 filled with a catalyst so as to form a plurality of layers and controlling operating conditions such as temperature. manufactured.

In addition, thermocouples are usually inserted in this reaction tube at regular intervals in the depth direction. The inserted thermocouples provide temperature information of the catalyst layer filled with catalyst and/or the inert layer filled with inert support. The temperature information obtained here is the in-pipe temperature information. The method of inserting the thermocouple is not limited as long as it is a method known to those skilled in the art, and examples thereof include the following. The direction in which the thermocouple is inserted is the depth direction of the reaction tube and/or the direction perpendicular to the depth direction of the reaction tube. The method of inserting the thermocouple is a method of directly inserting the thermocouple in parallel with the reaction tube, and/or a method of inserting a case (thermowell) in which the thermocouple is inserted and inserting the thermocouple inside it (i.e., The reaction tube has a double tube structure). The mode of change in the position of the thermocouple over time is a fixed type that does not move at all and/or a type that moves to an arbitrary position within the reaction tube over time.

Note that the reaction tubes into which thermocouples are usually inserted are not all the reaction tubes in the reactor, but some of the reaction tubes. For example, among thousands to tens of thousands of reaction tubes, usually 5 to 100, preferably 6 to 50, more preferably 7 to 40, particularly preferably 8 to 16. Insert a thermocouple. Further, the reaction tubes into which the thermocouples are inserted may be selected from only a portion of, for example, three divided sections in FIG. 1, or may be selected from all sections without bias. However, in order to grasp the temperature of the entire reactor, it is preferable that the section in which at least one reaction tube is selected occupies 40% or more of the total section, more preferably 60% or more. , More preferably, it is a mode that occupies 75% or more of the compartment. For example, in FIG. 1, when one reaction tube is selected from section A, one from section B, and zero reaction tube from section C, sections in which at least one reaction tube is selected account for 67% of all sections. . The greater the number of compartments, the more accurate the analysis. Therefore, the number of compartments is usually 3 or more, preferably 4 or more, more preferably 5 or more, and particularly preferably 6 or more. The partitioning method is not particularly limited, and can be appropriately determined when selecting reaction tubes. In addition to the selection of the section, it is also important to grasp the temperature information evenly in the radial direction within the plane of the multi-tubular reactor 10 as shown in FIG. In the present invention, unless otherwise specified, a reaction tube into which a thermocouple is inserted is simply referred to as a reaction tube.
The temperature information is information obtained by measuring the catalyst peak temperature during air treatment, and is information used to grasp how close the catalyst peak temperature is to the use limit temperature of the catalyst. As will be described later, the temperature information can also be used to understand the air treatment status. For example, when the catalyst peak temperature during air treatment remains flat over time, it can be determined that coke combustion is not occurring and air treatment is complete.

The air treatment of the multitubular reactor 10 in the present embodiment means that the reaction tube 20 filled with a catalyst for producing at least one of unsaturated aldehydes, unsaturated carboxylic acids, and conjugated dienes is oxidized for a certain period of time. After the reaction (hereinafter also referred to as operation), air containing no hydrocarbons and a molecular oxygen-containing gas are used as the inlet gas, and some or all of the inlet gas flow rate, reaction bath temperature, and reactor pressure are appropriately set. represent. The treatment is, for example, for the purpose of removing coke-like carbon compounds accumulated inside and outside the catalyst due to long-term reaction, regenerating the catalyst in a reduced state, improving performance by reoxidizing the catalyst, etc. It is the process that takes place. As shown in Table 1, the air treatment consists of one or more treatment steps, and the treatment of changing part or all of each inlet gas flow rate, reaction bath temperature and reactor pressure constitutes one treatment step. Configure. As mentioned above, since the actual plant is in a shutdown state during air treatment, it is necessary to proceed with the treatment steps quickly. It wasn't easy. The method of the present invention is for obtaining support information for making this determination more simply, efficiently, and quickly. By completing the air treatment in a short time, unnecessary activation of the catalyst can sometimes be prevented. This also has the advantage of reducing loss due to combustion of the target product due to unnecessary activation of the catalyst until recovery of selectivity and yield from restart. Catalyst species that cause such unwanted activation include, for example, a composite metal oxide catalyst containing molybdenum and bismuth as essential elements. The method of the present invention is particularly suitably applied to multitubular reactors using such catalysts.

The information about gas flowing in and out in the present invention (hereinafter referred to as inflow and outflow gas information) refers to the gas introduced into the reactor inlet side by air treatment (inlet gas) and/or the gas discharged from the outlet side ( outlet gas). The inflow and outflow gas information preferably includes information about the composition of the outlet gas, more preferably about the amount of carbon dioxide contained in the outlet gas. Inflow and outflow gas information can be obtained, for example, by analyzing the inlet gas and/or the outlet gas by gas chromatography. Furthermore, by processing the information on the amount of carbon dioxide, it is also possible to derive the carbon treatment amount and the integrated carbon treatment amount. Here, it is known to those skilled in the art that part of the carbon dioxide produced by air treatment is detected as carbon monoxide by the water gas shift reaction or the like. That is, in the present invention, carbon dioxide refers to a mixed gas of carbon dioxide and carbon monoxide in a broader sense, and is used in this sense unless otherwise specified.

FIG. 3 is a diagram showing a flow chart of the method according to this embodiment. The method according to the present embodiment comprises a step S1 of acquiring inflow and outflow gas information of the multi-tubular reactor 10, and (1) numerically processing the inflow and outflow gas information into the multi-tubular reactor. and an output step S2 of outputting assistance information to assist the air treatment of 10. Specifically, in the output step S2, visualization processing such as graphing, processing of comparing with information at a time different from the air treatment or in a different reactor, and the like can be performed. The method according to this embodiment optionally further comprises a providing step S3 of providing assistance information to the user of the shell-and-tube reactor 10 . The providing step S3 may be performed by a computer device, or may be performed by providing the support information output by the computer device to the user of the multi-tubular reactor 10 by telephone or FAX. Also, the support information may be provided to the user's terminal via the network. The provision of the support information via the network may be performed by a computer device that outputs the support information, or may be performed by a device separate from the computer device.

In the acquisition step S1, the computer device may acquire the inflow and outflow gas information by input from the terminal of the user of the multi-tube reactor 10 or input from the administrator of the computer device using an input device such as a keyboard. Inflow and outflow gas information may be obtained by sampling the gas from the inlet side and/or the outlet side of the reactor 10 and automatically inputting analysis data by gas chromatography at regular time intervals. The inflow/outflow gas information may be configured to be input from a user's terminal connected to the computer device via a network. In addition, the user of the multi-tubular reactor 10 and the administrator of the computer may be the same. Specific aspects of the method according to this embodiment will be described below with reference to the drawings. However, the present invention is not limited to this specific embodiment, and is intended to include all modifications within the technical scope indicated by the claims.

A method in a specific embodiment includes causing a computer device to execute step S1 of acquiring inflow and outflow gas information in an air treatment process for a multi-tubular reactor 10 including tens of thousands of reaction tubes 20 . The multi-tubular reactor 10 may be divided into a plurality of compartments A, B, C, etc., as shown in FIG. Obtain information about the gas on the inlet side and/or the gas on the outlet side of the vessel 10 .

FIG. 4 is a diagram showing a graph derived as information on the outlet carbon dioxide amount by numerically processing the inflow and outflow gas information obtained in step 1 using a computer device (detailed data is shown in Table 1). belongs to). The information on the exit carbon dioxide amount is also an example of the assistance information in the present invention, and the process of outputting this itself corresponds to step S2, but it is also possible to obtain easier-to-understand assistance information by further calculation. In the example of FIG. 4, the molar concentration of each gas is calculated by multiplying a single analysis value (area value) by gas chromatography by a previously derived factor. The data may be statistically processed numerical values such as the average value, median value, or mode value of two or more area values to ensure reliability, and measurement data judged to be outliers as necessary as described later It may be a numerical value calculated after rejecting If the analysis value by gas chromatography shows an abnormal value when compared with the data before and after or with the air treatment operation data used as a reference, and the above rejection criteria are clearly shown, the gas chromatography measuring instrument itself is deemed to be inadequate. can also judge. In this case, the present invention also includes a function of automatically displaying an alert notifying that there is a defect in the measuring device, and explicitly indicating it to the user of the multi-tubular reactor. The amount of outlet carbon dioxide can be in units known to those skilled in the art, such as ppm shown in the example of FIG. In addition, the type of gas detected by gas chromatography is not particularly limited, and in addition to the carbon dioxide gas shown in the example of FIG. and condensable liquids thereof, hydrocarbon gases and condensable liquids thereof, which are products and by-products of the catalytic reaction. For example, in bismuth molybdate mixed metal oxide catalysts, it is known to those skilled in the art that the water vapor used in air treatment sublimates the molybdenum in the catalyst, deactivating the catalyst or causing plugging in downstream purification systems. . Therefore, (1) the time-integrated value of the total amount of water vapor that entered the catalyst during the air treatment, and/or (2) the maximum catalyst temperature obtained from the thermocouple during the air treatment and the amount of water vapor entering. It is conceivable to prepare in advance a calculation formula for issuing an alert when a numerical value based on the relationship (for example, maximum temperature x water vapor flow rate) reaches a predetermined value, and these aspects are also included in the present invention.

Criteria for rejecting data include (1) statistically known methods such as Q-test (Q-test), 4d rule, Dixon's method, Grubbs' method, and (2) the same depth in multiple reaction tubes. Whether the standard deviation of the exit carbon dioxide amount at the location is within the range of the parameters obtained by multiplying the analysis accuracy of each instrument by an appropriate factor (if not, discard the questionable data), and so on. Among the above, the Q test is particularly preferable because it can determine whether or not the value is an abnormal value based on statistical grounds. Confidence limits of 19%, 34%, 38%, 43%, 48%, 49%, 86%, 90%, 95% and 99.7% are employed, preferably 86%, 90%, 95%, most preferably 90%. In the present invention, the data rejection operation is not limited to the molar concentration of each gas described above, but is applied to all the data and parameters of the present invention.
In FIG. 4, for example, measurement No. At point 3 (see Table 1), the outlet _CO2 concentration has dropped to around 1000 ppm, and at a reaction bath temperature of 320° C., the shell-and-tube reactor user can visually determine that the carbon is burning. be able to. Therefore, it is possible to quickly move to the next processing step, which is to increase the air flow rate. As described above, the method of the present invention enables early determination of a change in processing steps simply by inputting the outlet gas analysis result. Also, measurement No. At 14, the outlet CO ₂ concentration is reduced to a level equivalent to the atmospheric CO ₂ concentration of 400 ppm. At this time, if the computer device is set so that the background of the cell is automatically displayed in a dot pattern when the CO ₂ concentration at the outlet reaches the same level as that in the atmosphere, measurement No. 1 in Table 1 can be obtained. A dot pattern such as 14 outlet _CO2 concentration columns is displayed. This allows the shell-and-tube reactor user to determine that the air treatment in this treatment step is complete. By comparing the outlet _CO2 concentration results with past air treatment data and/or technical knowledge in this way, the computer automatically makes judgments as necessary, and changes the display to indicate air treatment and treatment steps. A method of explicitly indicating to the user of the shell-and-tube reactor the completion of is also included in the present invention. Here, criteria for automatic determination by the above-described computer device will be described later.

FIG. 5 shows information on the amount of carbon treated per unit time obtained by numerically processing the information on the amount of carbon dioxide at the outlet. This numerical processing is also an example of the process of obtaining support information, and is a process included in step S2 in FIG. Specifically, the amount of carbon treated per unit time at a certain measurement point can be obtained by the following formula (1). As described above, if the unit of the outlet carbon dioxide amount (the outlet CO ₂ concentration in the step in the formula below) is different, the coefficient 1000000 in the formula below is also modified as necessary. Also, the unit of carbon treatment amount is not particularly limited, and conversion known to those skilled in the art is performed as necessary (for example, [mol/hr], etc.). The outlet gas flow rate can be used instead of the inlet gas flow rate, and the calculation formula in that case is the same.
Amount of carbon processed per unit time [g/hr] = Inlet gas flow rate at the time of measurement [NL/hr] x Outlet _CO2 concentration at the time of measurement [ppm] ÷ 1000000 ÷ 22.4 [NL/mol] x 12 [ g/mol] (1)
By converting from outlet _CO2 concentration to carbon throughput per unit time, the view taking into account the time interval between measurements of outlet _CO2 concentration and the gas flow rate in the reaction tubes is made explicit to the user of the shell-and-tube reactor. can be shown. The amount of carbon treated per unit time is used to determine the progress of air treatment through relative evaluation for the same air treatment. In addition, by comparing and collating the amount of carbon treated per unit time with past air treatment data and/or technical knowledge, the computer device automatically makes a judgment as necessary, and changes the display to change the air treatment and/or treatment step A method of explicitly indicating to the user of the shell-and-tube reactor the completion of is also included in the present invention. Here, criteria for automatic determination by the above-described computer device will be described later.
In FIG. 5, measurement No. The outlet CO ₂ concentration of measurement No. 10 is about 6300 ppm. Although the CO ₂ concentration at the outlet of No. 6 is sufficiently lower than 13000 ppm, the amount of carbon treated per unit time is as high as about 0.34 g/hr because the inlet air flow rate is doubled. That is, it can be said that the inclusion of carbon throughput per unit time as well as outlet _CO2 concentration as aiding information makes it easier to determine the completion of air treatment and/or treatment steps.

FIG. 6 shows information on the integrated carbon treatment amount obtained by numerically processing the information on the carbon treatment amount per unit time. This numerical processing is also an example of the process of obtaining support information, and is a process included in step S2 in FIG. Specifically, the integrated carbon treatment amount can be obtained by the following formula (2). The unit of the integrated carbon treatment amount is not particularly limited either, and conversion known to those skilled in the art is performed as necessary (for example, [mol]). In addition, in the following formula, the piecewise quadrature is calculated by trapezoidal interpolation, but the calculation method may be any method known to those skilled in the art, such as rectangular interpolation, as long as it does not greatly affect the determination.
Cumulative carbon treatment amount [g] = (carbon treatment amount per unit time [g/hr] at the time of measurement + carbon treatment amount per unit time [g/hr] at the measurement point immediately before the measurement time) / 2 × Processing time from the time of measurement to the time of measurement one before the time of measurement [hr] + Cumulative amount of carbon processed at the time of measurement one before the time of measurement [g] (2)
As is clear from FIG. 6, the cumulative amount of carbon treated leveled off when the air treatment time exceeded 9 hours. This is considered to mean that the coke-like carbon compounds in the reactor have almost disappeared, and can be judged to indicate the end point of the air treatment. In the example of FIG. 6, measurement No. The integrated carbon treatment amount in measurement No. 14 is The computer device automatically determines that the integrated carbon treatment amount is approximately the same as in 13, and the computer device automatically changes the display pattern of the background of the cell so that it is displayed in Table 1. Based on this indication, the shell-and-tube reactor user can determine that the air treatment in this treatment step is complete. In this way, by comparing and collating the result of the accumulated carbon treatment amount with the past air treatment data and/or technical knowledge, the computer device automatically judges as necessary, and changes the display to change the air treatment and treatment step. A method of explicitly indicating to the user of the shell-and-tube reactor the completion of is also included in the present invention. Here, criteria for automatic determination by the above-described computer device will be described later.
By using such visual information, even in the absence of a skilled technician, it is possible to quickly determine whether the air treatment has been completed using a fixed flow chart.
It is also possible to optimize the frequency of air treatment (how often air treatment is performed during the long-term reaction in the plant) and reaction conditions based on the calculation result of the cumulative carbon treatment amount. For example, it can be estimated that the product of the raw material supply flow rate and the operating time (that is, the cumulative reaction raw material throughput by the catalyst) is proportional to the cumulative carbon throughput in air treatment. Therefore, when the cumulative amount of carbon treated is about twice as large as expected, it is possible to optimize the frequency of air treatment, such as by doubling the frequency of the next air treatment. Regarding the optimization of reaction conditions, by accumulating data on how the cumulative carbon treatment amount in air treatment changes when gas conditions and operating conditions are changed in a long-term reaction, it will be possible to empirically Alternatively, it becomes easier to quantitatively find optimal conditions. Of course, the present invention also includes optimizing the frequency of air treatment and the reaction conditions of other plants with similar operating conditions based on the data of the cumulative amount of carbon processed in a certain plant.

FIG. 7 is a diagram showing information on the catalyst peak temperature. This catalyst peak temperature calculation process is also a subsequent step of obtaining support information, and is a process included in step S2 in FIG. In the example of FIG. 7, measurement No. 12, the catalyst peak temperature reached 378° C., so an alert with a different cell background display pattern is set to be displayed in Table 1. If the temperature rises above this level, the deterioration of the catalyst is considered to progress, but in this example, the catalyst peak temperature decreases after that. By comparing the result of catalyst peak temperature with past air treatment data and/or technical knowledge in this way, the computer device automatically makes judgments as necessary, changes the display, and performs air treatment and treatment steps. A method of explicitly indicating completion as supporting information for a shell-and-tube reactor is also intended to be included in the present invention. Here, criteria for automatic determination by the above-described computer device will be described later. Furthermore, the example of FIG. 7 plots the catalyst peak temperature itself, but the difference between the catalyst peak temperature and the reaction bath temperature is calculated as the catalyst heat generation temperature, the heat generation situation is grasped, and an alert is automatically issued. The method of doing is also included in the present invention.

Also, hypothetically, in the above example, measurement No. If the catalyst peak temperature becomes higher after 12, air treatment should be discontinued. For example, when the catalyst peak temperature reaches the use limit temperature of the catalyst -20 ° C., the flow of air and / or oxygen-containing gas is stopped, and if necessary, an inert gas such as nitrogen gas or steam is flowed. to interrupt air treatment. The use limit temperature of the catalyst varies depending on the type of catalyst and is set separately, but is, for example, 350°C to 550°C.

Next, the method for obtaining the catalyst peak temperature is shown below. In-tube temperature information (temperature information obtained by a temperature sensor (thermocouple) installed in each reaction tube) is obtained from multiple reaction tubes in the reactor, and the user of the reactor inputs it into a computer device using an input device. Alternatively, a computer device acquires pipe temperature information automatically and at regular time intervals. The obtained in-pipe temperature information is first summarized in a tabular format. At this time, the temperature information in the tubes at the same depth position is compared in multiple reaction tubes, statistical processing such as averaging is performed, and it is determined whether or not there is data to be rejected, and may be rejected if necessary. . Rejection criteria include (1) statistically known methods such as Q-test, 4d rule, Dixon's method, Grubbs' method, and (2) tube temperature at the same depth position in multiple reaction tubes. Judging whether the standard deviation is within the range of parameters obtained by multiplying the analytical accuracy of thermocouples and various instruments by an appropriate coefficient (if not, discard questionable data). Objects to be rejected may be reaction tubes containing specific thermocouples, specific compartments, specific measurement points of specific thermocouples, and combinations thereof. After discarding the data as necessary, the pipe temperature information is statistically processed. This statistical processing includes a method of using the average value, minimum value, maximum value, median value, and mode of data at the same depth position in a plurality of reaction tubes. In the case of an exothermic reaction, it is required to be able to appropriately grasp the runaway of the reaction and to judge it quickly. Therefore, the method of obtaining the maximum value is most preferable. The pipe internal temperature information thus statistically processed is visualized (plotted on a graph). A scatter diagram in which the horizontal axis is the distance from the inlet of the reaction tube and the vertical axis is the statistically processed in-tube temperature information at each depth position is most preferable, but any visualization known to those skilled in the art may be used. The visualization information obtained by this processing is also called the temperature distribution of the catalyst layer in the present invention. The data with the highest temperature in the temperature distribution is called catalyst peak temperature in the present invention.

Next, criteria for air treatment and/or completion of the treatment step based on the outlet CO ₂ concentration in the reaction tube, the amount of carbon treated per unit time, the cumulative amount of carbon treated, and the peak temperature of the catalyst will be described. Examples of data used for judgment criteria are the gas _composition at the reactor inlet (inlet _CO2 concentration by analysis) if the outlet CO2 concentration, _CO2 concentration in the air, past air treatment in similar or identical plants data, and air treatment data during the operation. For example, for the carbon throughput per unit time and cumulative carbon throughput, past air treatment data in similar or identical plants and air treatment data during the operation can be used. As for the catalyst peak temperature, the use limit temperature of the catalyst, past air treatment data in a similar or the same plant, and air treatment data during the operation can be used. As a method of judgment, if the data obtained at a certain measurement time is within the range of (the average value of the data used as the judgment criterion or the data itself) ± (the standard deviation of the data or the measurement accuracy) × the coefficient X For example, it is assumed that the air treatment or treatment step is completed and the next treatment is proceeded to. As described above, it is also included in the present invention that the determination is automatically performed by a computer device and the result of the determination is automatically included in supporting information such as graphs and tables to be explicitly shown to the user. If the above-mentioned coefficient X is too large, there is a risk that the air treatment will not be performed properly, and if it is too small, the time required for air treatment will become longer, and the productivity of the plant will deteriorate. From these points of view, the appropriate range of the coefficient X is 0.1 or more and 1000 or less. The upper limits of the coefficient X are 750, 500, 250, 150, 100, 90, 80, 70, 60, 50, 40, 30, 20, 10, 8, 6, 5, 4, 3, and 2.0 in order of preference. and the lower limits are 0.2, 0.5, 0.8 and 1.0 in order of preference. That is, the most preferable range of X is 1.0 or more and 2.0 or less. In addition to the above, the criteria for deciding when to terminate the air treatment and treatment steps may be calculated backward from the start date of plant operation, or the treatment may be terminated midway due to other circumstances. Judgment criteria are known.
After the judgment is made manually or automatically by a computer device according to the judgment criteria as described above, when moving from the relevant treatment step to the next treatment step, as described above, each inlet gas flow rate, reaction bath temperature and reactor Set some or all of the pressure appropriately. This setting is carried out according to the predetermined procedure manual for air treatment. These are known to those skilled in the art and are intended to be included in the present invention.

The method according to the present embodiment further comprises causing the computer device to perform an output step of outputting comparison information between the assistance information and assistance information output in the past air treatment in the multi-tubular reactor 10. may contain. By comparing the support information output in the past air treatment with the support information output in the current air treatment, it becomes easier to judge abnormalities in the air treatment and the reactor, and the air treatment It becomes easy to optimize the frequency. The support information output in the past air processing may be the support information output in the previous air processing, or the support information output in the past multiple times of air processing. It may be information obtained by statistically processing assistance information output in a plurality of times of air processing. As a specific aspect of the comparison information, for example, information such as outlet CO ₂ concentration, carbon treatment amount per unit time, integrated carbon treatment amount, catalyst peak temperature, etc., which is support information output in the air treatment currently being performed. , and the same information output in the past air treatment are collectively displayed in one table. As another example of comparative information, graphs plotting outlet _CO2 concentration, carbon throughput per unit time, integrated carbon throughput, catalyst peak temperature, etc. against air treatment time as shown in FIGS. , a graph in which similar graphs output as support information in the past air treatment are overlaid.

As an advantage of the present invention, scrutinize information such as the above-mentioned progress rate of air treatment, problems, elapsed time, etc., and information on input (heat medium temperature, flow rate of each gas such as air and steam, pressure control, etc.) in air treatment work However, in order to make the air treatment operation more efficient in the next or other similar plant, it becomes possible to consider the implementation timing of air treatment, the air treatment method, the timing of catalyst replacement, and necessary equipment modifications. The timing of air treatment is particularly important. If the pressure difference inside the reaction tube rises due to damage to the catalyst due to long-term reaction and the deposition of coke-like carbon compounds on the catalyst, and the gas stops flowing, the productivity of the plant will drop significantly. In addition, the operation of extracting the catalyst becomes complicated. In addition, by performing air treatment at an appropriate time, it is possible to maintain a stable high yield of the target product over a long period of time. Catalyst damage, deposition of coke-like carbon compounds, and reduction in the yield of the target product due to long-term reaction can be said to be deterioration of the catalyst in a broad sense. From the viewpoint of suppressing deterioration of the catalyst, it is also important to estimate the air treatment timing by the method of the present invention.

As already explained, in Table 1, the background pattern of the cell (No. 12) in which the catalyst peak temperature was as high as 378°C and the cell (No. 14) in which the air treatment was judged to be completed was It is displayed by changing it to a cell.

Although the present invention has been described above using the above-described embodiments as examples, the present invention is not limited to these. For example, in the above embodiment, the amount of carbon treated per unit time and the cumulative amount of carbon treated are calculated from the viewpoint of removing coke-like carbon compounds by air treatment. From the viewpoint of performing the reoxidation treatment, the oxygen absorption amount per unit time or the accumulated oxygen absorption amount may be calculated. The method of calculating the amount of oxygen absorbed per unit time and the accumulated amount of absorbed oxygen conforms to the method of calculating the amount of carbon treated per unit time and the accumulated amount of carbon treated as described above, and detailed description thereof will be omitted.

This application is based on Japanese Patent Application No. 2022-23452 filed on February 18, 2022, the contents of which are incorporated herein by reference.

The present invention relates to a multi-tube reactor containing a plurality of reaction tubes for producing unsaturated aldehydes, unsaturated carboxylic acids or conjugated dienes by oxidation reaction using a catalyst, and air treatment required according to the reaction time. , more efficiently and with less catalyst deterioration.

10: multitubular reactor, 20: reaction tube, 22, 24, 26, 28: catalyst layer, 30: support ring, S1: acquisition step, S2: output step, S3: provision step

Claims

A method for supporting air treatment of a shell-and-tube reactor comprising a plurality of reactor tubes producing unsaturated aldehydes and/or unsaturated carboxylic acids by catalytic oxidation or conjugated dienes by oxidative dehydrogenation. and
computer equipment,
an obtaining step of obtaining, as reaction information, information on gases flowing into and out of the reactor;
and an output step of numerically processing the reaction information to output assistance information for assisting the air treatment.
the reaction information includes information about gas composition at the outlet of the shell-and-tube reactor;
The support information includes at least one of information on the integrated carbon throughput of the multi-tubular reactor or information on the carbon throughput per unit time of the multi-tubular reactor,
The method of claim 1 for supporting air handling.
the reaction information includes information about gas composition at the outlet of the shell-and-tube reactor;
The support information includes at least one of information on the accumulated oxygen absorption amount of the multi-tubular reactor and information on the oxygen absorption amount per unit time of the multi-tubular reactor.
The method of claim 1 for supporting air handling.
the reaction information includes information about the temperature distribution in the reaction tubes of the multi-tubular reactor;
The support information includes information about changes in the pipe temperature distribution over time during the air treatment.
4. A method of supporting air handling according to any one of claims 1-3.
to the computer device,
5. The method according to any one of claims 1 to 4, further comprising executing an output step of outputting comparison information between the assistance information and assistance information output in past air processing in the multitubular reactor. How to support air handling as described.
Apparatus to support air treatment in multi-tube reactors containing multiple reaction tubes producing unsaturated aldehydes and/or unsaturated carboxylic acids by catalytic oxidation or conjugated dienes by oxidative dehydrogenation. and
The device has an acquisition unit and an output unit,
The acquisition unit is configured to acquire information about gas flowing into and out of the reactor as reaction information,
The output unit is configured to output support information for supporting the air treatment by numerically processing the reaction information.
A device that supports air handling.