In-situ sampling and molecular weight measurement system of batch reactor

Abstract

An in-situ sampling and molecular weight measurement system of a batch reactor is disclosed. The system comprises: a batch reactor including an inlet through which a reactant solution is selectively supplied and an outlet through which a product formed by reaction of the reactant solution is selectively discharged; a sampling line connected to the reactor and through which the reactant solution in reaction selectively flows; and a plurality of sampling valves mounted on the sampling line and configured to selectively open and close the sampling line, wherein the plurality of sampling valves are configured to be sequentially opened and closed from those located relatively close to the batch reactor to those located relatively farther from the batch reactor.

Description

In-situ sampling and molecular weight measurement system for batch reactors

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2024-0077787, filed June 14, 2024, the entire contents of which are incorporated herein by reference.

[0003] The present invention relates to an in-situ molecular weight measurement system for a batch reactor, and more particularly, to an in-situ sampling and molecular weight measurement system for a batch reactor capable of sampling a sample in real time while maintaining the internal pressure in a high-pressure batch reactor and measuring the molecular weight, etc. of the sampled sample in real time.

[0004] A batch reactor is a device for performing chemical reactions. Chemical reactions using a batch reactor typically proceed through the following process.

[0005] First, the reactants are placed in the reactor and uniformly mixed using a mixer. Then, the reaction conditions are controlled using temperature and pressure controllers, and an appropriate reaction time is set as the reaction progresses. Through this process, the desired reaction can be efficiently performed under the desired conditions.

[0006] To set an appropriate reaction time, it is necessary to monitor the progress of the reaction in real time. However, conventional batch reactors have found it difficult to sample internal substances during the reaction. In particular, high-pressure batch reactors have found it extremely difficult to sample internal substances while maintaining the internal pressure required for the reaction.

[0007] Typically, in conventional batch reactors, pressure is completely released upon reaction completion to analyze the internal material. Therefore, it is difficult to directly monitor the progress of the reaction. Even when sampling the material inside the reactor during the reaction, the long sampling and drying times for analysis make it difficult to analyze information such as conversion, selectivity, or molecular weight in real time.

[0008] The information contained in this background section is intended to enhance understanding of the background of the invention and may include matters that are not prior art and are already known to those of ordinary skill in the art.

[0009] An embodiment of the present invention is to provide an in-situ sampling and molecular weight measurement system for a batch reactor, which can sample a sample in real time while maintaining the internal pressure in a high-pressure batch reactor and measure the molecular weight, etc. of the sampled sample in real time.

[0010] An in-situ sampling and molecular weight measurement system for a batch reactor according to an embodiment of the present invention comprises: a batch reactor including an inlet through which a reactant solution is selectively supplied, and an outlet through which a product formed by the reaction of the reactant solution is selectively discharged; a sampling line connected to the reactor through which a reactant solution in the process of reacting selectively flows; and a plurality of sampling valves mounted on the sampling line and configured to selectively open and close the sampling line, wherein the plurality of sampling valves may be configured to sequentially open and close from a sampling valve relatively close to the batch reactor to a sampling valve relatively far from the batch reactor.

[0011] The system may further include a Melt Flow Index (MFI) meter disposed in the sampling line downstream of the plurality of sampling valves and configured to measure the melt flow index (MFI) of the reactant solution flowing through the sampling line.

[0012] The plurality of sampling valves include a first sampling valve disposed relatively close to the batch reactor; and a second sampling valve disposed relatively close to the MFI meter, wherein the first sampling valve is configured to open and close a portion of a sampling line in which the first sampling valve is located, and the second sampling valve is configured to open and close a portion of the sampling line in which the second sampling valve is located, and the second sampling valve may be configured to open and close after the first sampling valve is opened and closed during sampling of the reactant solution.

[0013] The system may further include an inert gas supply source connected to the sampling line between the first and second sampling valves via an inert gas line and configured to supply inert gas to the sampling line.

[0014] The above inert gas line can be connected to the sampling line between the first and second sampling valves via a cleaning line.

[0015] The system may further include a steam supply source connected to the sampling line between the first and second sampling valves via a steam line and configured to supply steam or cleaning fluid to the sampling line.

[0016] The above steam line can be connected to a sampling line between the first and second sampling valves via a washing line.

[0017] The system may further include a check valve mounted on the washing line to prevent the reactant solution in the sampling line from flowing back into the washing line.

[0018] The system may further include heat tracing configured to keep the sampling line warm above a set temperature.

[0019] The above MFI meter may be equipped with a heat retention function to maintain the solution inside it at a set temperature or higher.

[0020] The system may further include a pressure sensor mounted in the sampling line upstream of the MFI meter and configured to measure the pressure within the sampling line upstream of the MFI meter.

[0021] The system may further include an inert gas valve disposed in the inert gas line and configured to open and close the inert gas line; a steam valve disposed in the steam line and configured to open and close the steam line; and a controller connected to the pressure sensor and configured to control the first and second sampling valves, the inert gas valve, and / or the steam valve based on a pressure in the sampling line upstream of the MFI meter.

[0022] The controller may be configured to be connected to an MFI meter to receive the measured MFI and to calculate the molecular weight of the reactant solution using the MFI.

[0023] According to the present invention, a separate sampling line is provided at the bottom of a batch reactor, a plurality of valves are installed in the sampling line, and when the plurality of valves are sequentially opened to sample a material inside the reactor, the pressure inside the reactor can be prevented from decreasing.

[0024] Additionally, a Melt Flow Index (MFI) measuring device can be installed on the sampling line to measure molecular weight, etc. in situ and in real time simultaneously with sampling of the internal material of the reactor.

[0025] Additionally, heat tracing can be installed in the sampling line to prevent the sampled material from solidifying.

[0026] Additionally, the steam line and inert gas line are connected to facilitate maintenance, such as cleaning of the sampling line.

[0027] In addition, the effects that can be obtained or expected from embodiments of the present invention will be disclosed directly or implicitly in the detailed description of the embodiments of the present invention. That is, the various effects expected according to embodiments of the present invention will be disclosed in the detailed description that follows.

[0028] Embodiments of the present disclosure may be better understood by reference to the following description taken in conjunction with the accompanying drawings in which like reference numerals designate identical or functionally similar elements.

[0029] Figure 1 is a schematic diagram of an in-situ sampling and molecular weight measurement system of a batch reactor according to an embodiment of the present invention.

[0030] Figure 2 is an enlarged view of part A of Figure 1.

[0031] The drawings referenced above are not necessarily drawn to scale, but should be understood to present rather simplified representations of various preferred features that illustrate the basic principles of the present invention. For example, specific design features of the present disclosure, including specific dimensions, orientations, positions, and shapes, will be determined in part by the specific intended application and usage environment.

[0032] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present invention. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly dictates otherwise. It will also be understood that the terms "comprises" and / or "comprising," when used herein, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. As used herein, the term "and / or" includes any one or all combinations of the associated listed items.

[0033] Additionally, it is understood that one or more of the methods or aspects thereof below may be implemented by at least one controller. The term "controller" may refer to a hardware device comprising a memory and a processor. The memory is configured to store program instructions, and the processor is specifically programmed to execute the program instructions to perform one or more processes described in more detail below. The controller may control the operation of units, modules, components, devices, or the like, as described herein. It is also understood that the methods below may be implemented by a device comprising the controller in conjunction with one or more other components, as will be appreciated by those skilled in the art.

[0034] Additionally, the controller of the present disclosure may be implemented as a non-transitory computer-readable recording medium containing executable program instructions executed by a processor. Examples of computer-readable recording media include, but are not limited to, read-only memory (ROM), random-access memory (RAM), compact disc (CD) ROM, magnetic tapes, floppy disks, flash drives, smart cards, and optical data storage devices. The computer-readable recording medium may also be distributed across a computer network so that the program instructions are stored and executed in a distributed manner, such as on a telematics server or a Controller Area Network (CAN).

[0035] According to an embodiment of the present invention, an in-situ sampling and molecular weight measurement system for a batch reactor is disclosed. The system comprises a batch reactor including an inlet through which a reactant solution is selectively supplied and an outlet through which a product formed by the reaction of the reactant solution is selectively discharged; a sampling line connected to the reactor through which a reactant solution undergoing a reaction selectively flows; and a plurality of sampling valves mounted on the sampling line and configured to open and close the sampling line. The plurality of sampling valves are configured such that a sampling valve relatively close to the batch reactor opens and closes, and a sampling valve relatively far from the batch reactor opens and closes. Accordingly, the amount of reactant solution flowing out through the sampling line during sampling is limited, and pressure fluctuations within the batch reactor can be reduced.

[0036] The system further includes a Melt Flow Index (MFI) measuring device arranged in the sampling line downstream of the plurality of sampling valves and configured to measure the melt flow index (MFI) of the reactant solution passing through the sampling line. Accordingly, the molecular weight, etc. of the reactant solution can be measured in situ and in real time simultaneously with sampling of the reactant solution.

[0037] The above system may further include heat tracing configured to maintain the sampling line at a temperature above a set temperature. Accordingly, a decrease in the temperature of the reactant solution within the sampling line can be prevented, thereby preventing the reactant solution from solidifying within the sampling line.

[0038] The plurality of sampling valves may include at least first and second sampling valves. The first sampling valve is relatively close to the batch reactor, and the second sampling valve is relatively close to the MFI meter. The system further includes an inert gas line connected to the sampling line between the first and second sampling valves and connected to an inert gas supply source. By supplying inert gas to the sampling line upstream of the MFI meter through the inert gas line, the pressure in the sampling line can be maintained constant. Furthermore, in order to control the supply of the inert gas, the system further includes a pressure sensor configured to measure the pressure in the sampling line in the sampling line upstream of the MFI meter. Furthermore, the system further includes a steam line connected to the sampling line between the first and second sampling valves and connected to a steam supply source. By supplying steam to the sampling line upstream of the MFI meter through the steam line, the sampling line can be flushed.

[0039]

[0040] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings.

[0041] FIG. 1 is a schematic diagram of an in-situ sampling and molecular weight measurement system of a batch reactor according to an embodiment of the present invention, and FIG. 2 is an enlarged view of part A of FIG. 1.

[0042] As illustrated in FIGS. 1 and 2, the in-situ sampling and molecular weight measurement system (10) of a batch reactor according to an embodiment of the present invention includes a batch reactor (20), a reactant supply source (30), a sampling line (40), and a melt flow index (MFI) measuring device (50).

[0043] The batch reactor (20) is a place where a reaction of reactants occurs. An inlet (22) is provided at the top of the batch reactor (20), and a reactant solution is selectively supplied to the batch reactor (20) through the inlet (22). An outlet (24) is provided at the bottom of the batch reactor (20), and a product produced by the reaction of the reactant solution is discharged from the batch reactor (20) through the outlet (24). The batch reactor (20) may be equipped with a stirring device for stirring the reactant solution, a pressure control device for controlling the pressure inside the reactor, and a temperature control device (e.g., a heater, etc.) for controlling the temperature inside the reactor.

[0044] The reactant supply source (30) stores the reactant and is connected to the inlet (22) of the batch reactor (20) via the supply line (32). The reactant stored in the reactant supply source (30) can be supplied to the batch reactor (20) via the supply line (32) and the inlet (22). For example, if the product is polyamide strands, the reactant can be adipic acid (ADA), pentamethylene diamine (PMDA), water, etc. The batch reactor (20) may further include a plurality of reactant supply sources (30), a plurality of supply lines (32) including each supply line (32) connecting each reactant supply source (30) to the inlet (22) of the batch reactor (20), and a plurality of supply valves including each supply valve (not shown) mounted on each supply line (32) to open and close the corresponding supply line (32).

[0045] The outlet (24) of the above batch reactor (20) is connected to a drain line (34), and a drain valve (36) is mounted on the drain line (34). When the reaction of the reactants is completed, the drain valve (36) opens the drain line (34) to discharge the product and unreacted substances to the outside of the batch reactor (20), particularly to a water tank, through the drain line (34).

[0046] A sampling line (40) is connected to the lower part of the batch reactor (20), and the reactant solution inside the batch reactor (20) can be selectively sampled through the sampling line (40). The sampling line (40) is equipped with a plurality of sampling valves (42, 43, 44), and each sampling valve (42, 43, 44) is arranged at a different position on the sampling line (40) and is configured to open and close the sampling line (40). Here, three sampling valves are provided as an example, but the number of sampling valves is not limited to three. However, for the convenience of explanation, a case in which three sampling valves (42, 43, 44) are provided is described as an example.

[0047] The first sampling valve (42) is positioned relatively close to the batch reactor (20), the third sampling valve (44) is positioned relatively close to the MFI measuring device (50), and the second sampling valve (43) is positioned between the first sampling valve (42) and the third sampling valve (44). The first, second, and third sampling valves (42, 43, 44) are configured so that after the first sampling valve (42) relatively close to the batch reactor (20) opens and closes, the second sampling valve (43) opens and closes, and then the third sampling valve (44) opens and closes. When the first sampling valve (42) is opened and closed, a reactant solution corresponding to the distance between the first and second sampling valves (42, 43) is sampled, when the second sampling valve (43) is opened and closed, the sampled reactant solution flows to the third sampling valve (44), and when the third sampling valve (44) is opened and closed, the sampled reactant solution flows to the MFI measuring device (50) (refer to the dotted line in FIG. 2, in which the dotted line indicates the flow of the reactant solution). Accordingly, the amount of the reactant solution sampled during sampling is limited, and thereby the pressure fluctuation inside the batch reactor (20) can be small.

[0048] A vent line (46) is connected to the downstream portion of the above sampling line (40), and a vent valve (48) configured to open and close the vent line (46) is mounted on the vent line (46). For example, the vent line (46) may be connected to the sampling line (40) between the second sampling valve (43) and the third sampling valve (44), but is not limited thereto. The vent line (46) may be opened by the vent valve (48) when the sampling line (40) is cleaned, so that the molten material remaining in the sampling line (40) may be discharged through the vent line (46). In addition, when the pressure within the sampling line (40) is too high, the vent valve (48) may open the vent line (46) to discharge a portion of the reactant solution within the vent line (46) to the outside, thereby lowering the pressure within the sampling line (40) (see the dotted line in FIG. 2).

[0049] The MFI meter (50) is mounted on the sampling line (40) downstream of the third sampling valve (44). The MFI meter (50) is connected to the sampling line (40), and the reactant solution flowing through the sampling line (40) flows into the MFI meter (50). In addition, the MFI meter (50) is connected to the MFI drain line (52), and the reactant solution that flows into the MFI meter (50) and passes through the MFI meter (50) can be discharged to the outside through the MFI drain line (52) (see the dotted line in FIG. 2). The MFI meter (50) is configured to measure the melt index (MFI) of the reactant solution passing through the MFI meter (50). The MFI is related to the time it takes for the reactant solution to pass through the MFI meter (50). A large MFI means good melt flowability, which means a small molecular weight of the melt. In contrast, if the MFI is small, the flowability of the melt is poor, which means that the molecular weight of the melt is large. Therefore, by measuring the MFI of the melt, the molecular weight of the melt can be indirectly measured. In this way, according to an embodiment of the present invention, when sampling the reactant solution using a plurality of sampling valves (42, 43, 44), the MFI of the sampled reactant solution can also be measured in situ through the MFI measuring device (50). Therefore, the molecular weight, etc. of the reactant solution can be measured in situ and in real time simultaneously with the sampling of the reactant solution.

[0050] In order to measure the molecular weight, etc. of the reactant solution in situ using the MFI meter (50), the reactant in the sample line (40) must be present in a molten state. For this purpose, the system (10) further includes a heat tracing (80) configured to supply heat to at least the sampling line (40), preferably the sampling line (40), the vent line (46), and the MFI drain line (52) to maintain the temperature above a set temperature. For example, in the case of a polyamide polymerization reaction, the set temperature may be 260°C, but is not limited thereto. The set temperature may be set according to the reaction occurring in the batch reactor (20).

[0051] The heat tracing (80) is not limited to the type as long as it is a device that can maintain the solution within the sampling line (40), the vent line (46), and the MFI drain line (52) above the set temperature. For example, the heat tracing (80) may be a double jacket that surrounds the sampling line (40), the vent line (46), and the MFI drain line (52) and allows the heat to flow therein, or may be a heat transfer band wrapped around the sampling line (40), the vent line (46), and the MFI drain line (52). The heat tracing (80) maintains the solution within the sampling line (40), the vent line (46), and the MFI drain line (52) above the set temperature to prevent the solution from solidifying within the lines (40, 46, 52) and blocking the lines (40, 46, 52). In addition, the above MFI measuring device (50) is equipped with a heat retention function to maintain the solution inside it above a set temperature.

[0052] The above system (10) may further include a steam supply source (70) for supplying steam to the sampling line (40) and an inert gas supply source (73) for supplying an inert gas to the sampling line (40).

[0053] A steam supply source (70) is connected to a sampling line (40) through a steam line (71), and a steam valve (72) is mounted on the steam line (71) to open and close the steam line (71). The steam line (71) is connected to a sampling line (40) downstream of a first sampling valve (42), preferably between the first sampling valve (42) and the second sampling valve (43), so that the steam supply source (70) supplies steam to the sampling line (40) between the first sampling valve (42) and the second sampling valve (43) through the steam line (71) to wash the sampling line (40), the MFI meter (50), the MFI drain line (52), and / or the vent line (46) with steam (see the solid line in FIG. 2, where the solid line represents the flow of steam or inert gas). Alternatively, the steam source (70) may inject a cleaning solution (e.g., triethylene glycol, etc.) into the sampling line (40) via the steam line (71) instead of or in addition to steam to clean the sampling line (40), the MFI meter (50), the MFI drain line (52), and / or the vent line (46).

[0054] An inert gas supply source (73) is connected to a sampling line (40) through an inert gas line (74), and an inert gas valve (75) is mounted on the inert gas line (74) to open and close the inert gas line (74). The inert gas line (74) is connected to a sampling line (40) downstream of a first sampling valve (42), preferably between the first sampling valve (42) and the second sampling valve (43), so that the inert gas supply source (73) can supply an inert gas to the sampling line (40) between the first sampling valve (42) and the second sampling valve (43) through the inert gas line (74). For example, when the pressure in the sampling line (40) is low and the reactant solution in the sampling line (40) does not flow smoothly to the MFI meter (50), the inert gas supply source (73) supplies an inert gas to the sampling line (40) through the inert gas line (74) to maintain the pressure in the sampling line (40) constant, thereby allowing the reactant solution in the sampling line (40) to flow smoothly to the MFI meter (50). In addition, the inert gas supplied to the sampling line (40) through the inert gas line (74) can wash the sampling line (40), the MFI meter (50), the MFI drain line (52), and / or the vent line (46) (see the solid line in FIG. 2). Here, the inert gas may be, but is not limited to, nitrogen.

[0055] The steam line (71) and the inert gas line (74) are joined to a washing line (76) and connected to a sampling line (40) through the washing line (76). A washing valve (77) is mounted on the washing line (76) to open and close the washing line (76). For example, when the pressure of the sampling line (40) is low or the reactant solution does not flow smoothly to the MFI meter (50), the washing valve (77) opens the washing line (76) to allow inert gas and / or steam to be supplied to the sampling line (40). In this case, depending on the required operation, the steam valve (72) may open the steam line (71) and / or the inert gas valve (75) may open the inert gas line (74).

[0056] The above washing line (76) may further be equipped with a check valve (78). The check valve (78) is mounted in the washing line (76) close to the sampling line (40) to prevent the reactant solution in the sampling line (40) from flowing back into the washing line (76).

[0057] In this specification, the steam line (71) and the inert gas line (74) are described as being joined to a washing line (76) and indirectly connected to a sampling line (40) through the washing line (76); however, each of the steam line (71) and the inert gas line (74) may be directly connected to the sampling line (40) without going through the washing line (76). In this case, the steam line (71) and the inert gas line (74) may each be equipped with a check valve (78).

[0058] The above system (10) further includes a pressure sensor (60) and a controller (90).

[0059] A pressure sensor (60) is mounted on a sampling line (40) upstream of an MFI meter (50) to measure the pressure in the sampling line (40) upstream of the MFI meter (50) and transmit a signal thereto to the controller (90).

[0060] The controller (90) is connected to the pressure sensor (60) to receive a signal regarding the pressure in the sampling line (40) upstream of the MFI meter (50). The controller (90) may be connected to valves within the system (10), such as the drain valve (36), the first, second, and third sampling valves (42, 43, 44), the vent valve (48), the steam valve (72), the inert gas valve (75), and / or the purge valve (77), to control the operation of the valves. In one example, the controller (90) may control the drain valve (36) to open the drain line (34) in response to completion of a target reaction within the batch reactor (20). In another example, the controller (90) may control the sequential opening and closing of the first, second, and third sampling valves (42, 43, 44) in response to receiving a request for sampling and molecular weight measurement of the reactant solution. In another example, the controller (90) may control the inert gas valve (75) to open the inert gas line (74) in response to determining that the pressure in the sampling line (40) measured by the pressure sensor (60) is lower than the lower pressure limit, the controller (90) may control the wash valve (77) to open the wash line (76), and the inert gas supply source (73) to supply inert gas to the sampling line (40). In another example, the controller (90) may, in response to determining that the pressure within the sampling line (40) measured by the pressure sensor (60) is lower than the upper pressure limit, control the vent valve (48) to open the vent line (46) to lower the pressure within the sampling line (40).In another example, the controller (90) may, in response to a determination that the sampling line (40) requires cleaning (e.g., completion of sampling and molecular weight measurement of the reactant solution or that the flow of the reactant solution within the sampling line (40) is not smooth, control the inert gas valve (75) to open the inert gas line (74) and / or the steam valve (72) to open the steam line (71), control the wash valve (77) to open the wash line (76), control the second and third sampling valves (43, 44) to open the sampling line (40) downstream of the first sampling valve (42), control the vent valve (48) to open the vent line (46), control the inert gas supply source (73) to supply inert gas to the sampling line (40) or control the steam supply source (70) to inject steam or a wash solution into the sampling line (40).

[0061] In addition, the controller (90) is connected to an MFI measuring device (50) and can calculate the molecular weight corresponding to the MFI measured by the MFI measuring device (50).

[0062]

[0063] (Examples and Comparative Examples)

[0064] According to Examples 1 to 3, adipic acid (ADA), pentamethylene diamine (PMDA), water, etc. were supplied to a batch reactor (20) according to a general polyamide manufacturing method, the reactant solution was stirred, and the temperature and pressure inside the batch reactor (20) were controlled so that the polymerization reaction was in progress. At the same time, the reactant solution was sampled through a sampling line (40) and the MFI of the reactant solution was measured through an MFI measuring device (50).

[0065] According to Comparative Examples 1, 3, and 5, polyamide was manufactured according to the above polyamide manufacturing method, the manufactured polyamide was melted, and then the MFI of the polyamide solution was measured using a conventional MFI measuring device.

[0066] According to Comparative Examples 2, 4, and 6, polyamide was manufactured according to the above polyamide manufacturing method, the manufactured polyamide was melted, and the relative viscosity (based on sulfuric acid) of the polyamide solution was measured using a relative viscosity measuring device.

[0067] The experimental results of the examples and comparative examples are listed in Table 1.

[0068] Measurement timeSample drying timeSampling timeTotal sample analysis timeAnalysis resultError(%)Example 15 min 0 min 2 min 7 min 80 (g / 10min @ 270℃) 12Comparative example 1 10 min 7 20 min 180 min 9 10 min 80 (g / 10min @ 270℃) 10Comparative example 2 240 min 7 20 min 180 min 1 140 min 2.76 (based on sulfuric acid) 1.6Example 2 5 min 0 min 2 min 7 min 105 (g / 10min @ 270℃) 15Comparative example 3 8 min 7 20 min 180 min 9 0 8 min 1 10.4 (g / 10min @ 270℃) 13.6Comparative example 4 240 min 7 20 min 180 min 1 140 min 2.50 (based on sulfuric acid) 1.6Example 3 5 min 0 min 2 min 7 min 50 (g / 10min @ 270℃)10Comparative Example 512 min 720 min 180 min 912 min 51.7 (g / 10min @ 270℃)9Comparative Example 6240 min 720 min 180 min 1140 min 2.94 (based on sulfuric acid) 1.6

[0069] Referring to Table 1, in the case of Examples 1 to 3, sampling is performed in situ during the reaction of the reactant solution, so the sampling time is very short at 2 minutes (sequential opening and closing time of the 1st, 2nd, and 3rd sampling valves (42, 43, and 44)), but in the case of the comparative examples, since the completed polyamide is used after the polymerization reaction of the polyamide is completed, the sampling time is the polymerization reaction time of the polyamide. Accordingly, the sampling time of the comparative examples is very long at 180 minutes. In the case of the examples, sampling and MFI measurement are performed simultaneously in situ during the reaction of the reactant solution, so there is no sample drying time, but in the case of the comparative examples, the moisture content of the polyamide solution must be lowered to measure the MFI or relative viscosity, so at least 10 hours or more is required.

[0070] The total sample time is the sum of the measurement time, sample drying time, and sampling time. In the case of the Examples, the total sample time is very short at about 7 minutes, but in the case of Comparative Examples 1, 3, and 5, the total sample analysis time is very long at over 900 minutes, and in the case of Comparative Examples 2, 4, and 6, the total sample analysis time is the longest at about 1140 minutes. In contrast, the error is the highest at about 15% in the Cases of the Examples, somewhat high at about 14% in the Cases of Comparative Examples 1, 3, and 5, and very low at 1.6% in the Cases of Comparative Examples 2, 4, and 6. Since the present invention is to check the progress of the reaction in real time by sampling and measuring molecular weight in situ, considering the total sample time and error, etc., the Examples are sufficient to achieve the purpose of the present invention, but it is difficult for the Comparative Examples to achieve the purpose of the present invention because sampling and measuring molecular weight in situ are not possible.

[0071]

[0072] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and includes all changes that can be easily modified and deemed equivalent by a person having ordinary skill in the art to which the invention pertains from the embodiments of the present invention.

Claims

1. A batch reactor including an inlet through which a reactant solution is selectively supplied and an outlet through which a product formed by the reaction of the reactant solution is selectively discharged; A sampling line connected to the above reactor through which the reactant solution in reaction selectively flows; and A plurality of sampling valves mounted on the above sampling line and configured to selectively open and close the sampling line; Includes, An in-situ sampling and molecular weight measurement system for a batch reactor, wherein the plurality of sampling valves are configured to sequentially open and close from a sampling valve relatively close to the batch reactor to a sampling valve relatively far from the batch reactor.

2. In paragraph 1, An in-situ sampling and molecular weight measurement system for a batch reactor further comprising a Melt Flow Index (MFI) meter disposed in the sampling line downstream of the plurality of sampling valves and configured to measure the melt flow index (MFI) of the reactant solution flowing in the sampling line.

3. In paragraph 2, The above multiple sampling valves a first sampling valve positioned relatively close to the batch reactor; and A second sampling valve positioned relatively close to the MFI meter; Including, The first sampling valve is configured to open and close a portion of the sampling line in which the first sampling valve is located, and the second sampling valve is configured to open and close a portion of the sampling line in which the second sampling valve is located. An in-situ sampling and molecular weight measurement system for a batch reactor configured such that a first sampling valve opens and closes when sampling a reactant solution, and then a second sampling valve opens and closes.

4. In paragraph 3, An in-situ sampling and molecular weight measurement system for a batch reactor further comprising an inert gas supply source connected to the sampling line between the first and second sampling valves via an inert gas line and configured to supply inert gas to the sampling line.

5. In paragraph 4, An in-situ sampling and molecular weight measurement system for a batch reactor, wherein the above inert gas line is connected to a sampling line between the first and second sampling valves via a washing line.

6. In paragraph 3, An in-situ sampling and molecular weight measurement system for a batch reactor further comprising a steam source connected to the sampling line between the first and second sampling valves via a steam line and configured to supply steam or a washing liquid to the sampling line.

7. In paragraph 6, An in-situ sampling and molecular weight measurement system for a batch reactor, wherein the steam line is connected to a sampling line between the first and second sampling valves via a washing line.

8. In paragraph 5 or paragraph 7, An in-situ sampling and molecular weight measurement system for a batch reactor further comprising a check valve mounted on the washing line to prevent the reactant solution in the sampling line from flowing back into the washing line.

9. In paragraph 2, An in-situ sampling and molecular weight measurement system for a batch reactor further comprising heat tracing configured to maintain the sampling line above a set temperature.

10. In paragraph 9, The above MFI meter is an in-situ sampling and molecular weight measurement system for a batch reactor having a heat retention function to maintain the solution therein above a set temperature.

11. In paragraph 4 or paragraph 6, An in-situ sampling and molecular weight measurement system for a batch reactor further comprising a pressure sensor mounted in a sampling line upstream of the MFI meter and configured to measure the pressure within the sampling line upstream of the MFI meter.

12. In paragraph 11, An inert gas line or steam line is connected to the sampling line between the first and second sampling valves through a cleaning line, The above system An inert gas valve arranged in an inert gas line and configured to open and close the inert gas line; A steam valve arranged in a steam line and configured to open and close the steam line; and A controller connected to the pressure sensor and configured to control the first and second sampling valves, the inert gas valve and / or the steam valve based on the pressure in the sampling line upstream of the MFI meter; An in-situ sampling and molecular weight measurement system for a batch reactor further comprising:

13. In paragraph 12, An in-situ sampling and molecular weight measurement system for a batch reactor, wherein the controller is connected to an MFI meter to receive the measured MFI and calculate the molecular weight of the reactant solution using the MFI.

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