Method for determining the filling state
The method efficiently determines catalyst filling state in reaction tubes by measuring representative values of gas flow and pressure, addressing the inefficiencies of conventional methods and ensuring high-quality hydrocarbon production.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- IHI CORP
- Filing Date
- 2024-12-18
- Publication Date
- 2026-06-30
Smart Images
Figure 2026106836000001_ABST
Abstract
Description
[Technical Field]
[0001] This disclosure relates to a method for determining the filling state. [Background technology]
[0002] Hydrocarbons are widely used as energy sources and raw materials for chemical products, and most are produced from fossil fuels. However, burning products derived from fossil fuels increases the concentration of carbon dioxide in the atmosphere, which is a major cause of global warming. On the other hand, hydrocarbons can be produced from raw materials that contain carbon dioxide. For example, it is expected that carbon dioxide emissions can be reduced by producing hydrocarbons from carbon dioxide contained in factory exhaust gases.
[0003] Incidentally, hydrocarbons can be produced in a multi-tube reactor filled with a catalyst. Patent Document 1 discloses a maintenance method for equalizing the differential pressure across each reaction tube. This maintenance method involves arbitrarily selecting at least 20% of the reaction tubes in the multi-tube reactor, flowing a predetermined flow rate of gas through each selected reaction tube, and measuring the differential pressure generated in each tube. The measured differential pressure is then compared with the average value of the differential pressure generated when the predetermined flow rate of gas is flowed through unused reaction tubes filled with the same type of catalyst, and reaction tubes showing abnormal differential pressures are separated and subjected to a predetermined treatment. [Prior art documents] [Patent Documents]
[0004] [Patent Document 1] Japanese Patent Publication No. 2005-334852 [Overview of the Initiative] [Problems that the invention aims to solve]
[0005] However, conventional techniques involve measuring the differential pressure generated in each reaction tube and comparing the measured differential pressure with the average initial differential pressure to identify reaction tubes exhibiting abnormal differential pressure. Therefore, conventional techniques may result in longer processing times for identifying reaction tubes exhibiting abnormal differential pressure.
[0006] The purpose of this disclosure is to provide a method for determining the packing state of a catalyst that can efficiently determine the packing state of the catalyst. [Means for solving the problem]
[0007] The packing state determination method according to this disclosure is a method for determining the packing state of catalysts packed in each of the multiple reaction tubes in a multi-tube reactor including multiple reaction tubes. The packing state determination method involves flowing gas through some of the multiple reaction tubes packed with catalysts, measuring characteristic values including at least one of the gas flow rate and differential pressure flowing through some of the reaction tubes, and determining the packing state of the catalyst in the reaction tubes based on representative values of the characteristic values.
[0008] The method for determining the filling state may involve calculating representative values of characteristic values and determining the filling state of the catalyst based on these calculated representative values.
[0009] Multiple reaction tubes may be divided into multiple lots, and one of these lots, the target lot, may contain some of the reaction tubes whose characteristic values are to be measured. The packing state determination method may measure the characteristic values of each reaction tube included in the target lot if the representative value of some of the reaction tubes is outside the range of the first threshold. The packing state determination method may also determine whether the characteristic values of each reaction tube included in the target lot are within the range of the second threshold.
[0010] The measure of central tendency may be the mean, median, or mode.
[0011] The catalyst may produce hydrocarbons.
[0012] The catalyst may be used without any additional equipment. [Effects of the Invention]
[0013] According to the present disclosure, it is possible to provide a filling state determination method capable of efficiently determining the filling state of a catalyst.
Brief Description of the Drawings
[0014] [Figure 1] It is a schematic diagram showing a catalyst filling state determination system according to an embodiment. [Figure 2] It is a schematic diagram showing a multitubular reactor according to an embodiment. [Figure 3] It is a flowchart showing a procedure for determining the filling state of a catalyst according to an embodiment. [Figure 4] It is an OC curve (Operating Characteristic curve) showing the relationship between the defective rate of a lot and the passing rate. [Figure 5] It is a graph showing the flow rate of each reaction tube of the first lot. [Figure 6] It is a graph showing the flow rate of each reaction tube of the second lot.
Modes for Carrying Out the Invention
[0015] Hereinafter, several exemplary embodiments will be described with reference to the drawings. Note that the dimensional ratios in the drawings are exaggerated for convenience of explanation and may be different from the actual ratios.
[0016] As shown in Figure 1, the filling state determination system 1 comprises a gas flow path 2, a compressor 3, a flow controller 4, a pressure gauge 5, a flow meter 6, and a multi-tube reactor 7. The compressor 3, flow controller 4, pressure gauge 5, flow meter 6, and multi-tube reactor 7 are arranged in the gas flow path 2 in this order. Gas G is supplied to the gas flow path 2. The compressor 3 compresses the gas G and supplies it to the multi-tube reactor 7. The flow controller 4 regulates the flow rate of the gas G that has been compressed by the compressor 3 and supplied to the multi-tube reactor 7. The pressure gauge 5 measures the pressure of the gas G supplied to the multi-tube reactor 7. The flow meter 6 measures the flow rate of the gas G supplied to the multi-tube reactor 7. The type of gas G is not particularly limited and may be air, for example.
[0017] As shown in Figure 2, the multitubular reactor 7 includes a plurality of reaction tubes 8. Each of the plurality of reaction tubes 8 is filled with catalyst 9. When a reaction is carried out in the multitubular reactor 7, the raw materials pass through the reaction tubes 8 and come into contact with the catalyst 9, thereby generating reaction products. The filling state determination system 1 according to this embodiment is a system for determining the filling state of the catalyst 9.
[0018] The multitube reactor 7 may include a fixed-bed reactor. The multitube reactor 7 may also be a shell-and-tube reactor. The multitube reactor 7 may include a plurality of reaction tubes 8 and a shell that houses the plurality of reaction tubes 8. By passing a heat transfer medium such as oil through the shell, the heat generated by exothermic reactions can be removed, thereby accelerating the reaction.
[0019] Catalyst 9 may produce hydrocarbons. Catalyst 9 may include at least one selected from the group consisting of, for example, nickel catalysts, ruthenium catalysts, iron catalysts, and cobalt catalysts. Catalyst 9 can be selected from the viewpoint of the type of hydrocarbon produced. Nickel catalysts or ruthenium catalysts can be used in methanation reactions to produce methane. Iron catalysts and cobalt catalysts can be used in FT reactions. Iron catalysts can mainly produce light hydrocarbons, and cobalt catalysts can mainly produce heavy hydrocarbons containing wax. Furthermore, iron catalysts can mainly produce alkenes and alkanes, and cobalt catalysts can mainly produce alkanes. Note that nickel catalysts are catalysts containing nickel as an active ingredient. Ruthenium catalysts are catalysts containing ruthenium as an active ingredient. Iron catalysts are catalysts containing iron as an active ingredient. Cobalt catalysts are catalysts containing cobalt as an active ingredient. The content of the active ingredient may be 20% by mass or more of the total catalyst.
[0020] The hydrocarbons produced in the multitubular reactor 7 may include at least one of alkanes and alkenes. These hydrocarbons can be produced by a methanation reaction or a Fischer-Tropsch (FT) reaction. The hydrocarbons produced in the multitubular reactor 7 may be used as sustainable aviation fuel (SAF). At least one of the alkanes and alkenes may contain at least one hydrocarbon having 1 to 100 carbon atoms. At least one of the alkanes and alkenes may contain at least one hydrocarbon having 1 to 4 carbon atoms. The alkanes may include, for example, at least one selected from the group consisting of methane, ethane, propane, and butane. The alkenes may include, for example, at least one selected from the group consisting of ethylene, propylene, 1-butene, 2-butene, isobutene, and 1,3-butadiene. Methane, ethane, and propane can be used as fuel for city gas. In addition, alkenes with 2 to 4 carbon atoms are useful as raw materials for plastics. The reaction product may also contain compounds other than hydrocarbons.
[0021] The raw materials supplied to the multi-tube reactor 7 may contain at least one of carbon monoxide and carbon dioxide, along with hydrogen. The carbon dioxide may include carbon dioxide recovered from a power plant or factory. Using such carbon dioxide as a raw material not only reduces the amount of carbon dioxide emitted from the power plant or factory, but also allows for the effective utilization of carbon dioxide. Furthermore, the hydrogen may be obtained by electrolyzing water using renewable energy sources such as solar, wind, and hydroelectric power. Using such hydrogen can reduce carbon dioxide emissions.
[0022] Next, the procedure for determining the charging state of catalyst 9 will be explained using the flowchart in Figure 3.
[0023] First, in step S1, catalyst 9 is packed into each of the multiple reaction tubes 8 in the multi-tube reactor 7. The catalyst 9 may be prepared in predetermined amounts and packed into each reaction tube 8 in predetermined amounts.
[0024] In step S2, gas is passed through some of the reaction tubes 8, which are filled with catalyst 9, and the characteristic values of the gas flowing through some of the reaction tubes 8 are measured. In step S2, the multiple reaction tubes 8 included in the multitube reactor 7 may be divided into multiple lots. For example, the multiple reaction tubes 8 included in the multitube reactor 7 may be divided into a total of 10 lots, from lot 1 to lot 10. Then, the target lot, which is one of the multiple lots, may contain the aforementioned some reaction tubes 8 whose characteristic values are measured. The method for selecting some of the reaction tubes 8 from the multiple reaction tubes 8 included in the target lot is not particularly limited, and for example, some of the reaction tubes 8 may be randomly selected from the target lot in accordance with the provisions of JIS Z9031:2012.
[0025] The number of reaction tubes 8 included in the multi-tube reactor 7 and the number of lots are arbitrary, and the number of lots and the number of reaction tubes 8 to be measured may be determined by prior testing. Figure 4 is an OC curve showing the relationship between the defect rate of a lot and the acceptance rate. Figure 4 shows OC curves for Examples 1 to 4. Example 1 is an OC curve when the number of reaction tubes 8 in a lot (lot size N) is 100 and the number of reaction tubes 8 sampled from the lot and measured (sample size n) is 19, measuring the characteristic values of approximately 1 / 5 of the reaction tubes 8 in the lot. Example 2 is an OC curve when the lot size N is 30 and the sample size n is 3, measuring the characteristic values of 1 / 10 of the reaction tubes 8 in the lot. Example 3 is an OC curve when the lot size N is 20 and the sample size n is 4, measuring the characteristic values of 1 / 5 of the reaction tubes 8 in the lot. Example 4 shows the OC curve when the lot size N is 20 tubes and the sample size n is 2 tubes, and the characteristic values of 1 / 10 of the reaction tubes 8 in the lot were measured.
[0026] As shown in Figure 4, the OC curve depends on the lot size N and the sample size n. Specifically, as shown in Example 1, the larger the lot size N and sample size n, the steeper the slope of the OC curve, which improves the accuracy of sorting unsuitable lots, but may lead to over-quality products and increased labor costs such as refilling. On the other hand, as shown in Examples 2 to 4, the smaller the lot size N and sample size n, the shallower the slope of the OC curve, which lowers the accuracy of sorting unsuitable lots, but reduces labor costs such as refilling. Therefore, when producing high-quality products in a multi-tube reactor 7, the lot size N and sample size n should be set to be large. On the other hand, when prioritizing work efficiency, the lot size N and sample size n should be set to be small. Thus, in the filling state determination method according to this embodiment, the lot size N and sample size n can be freely determined considering the balance between labor costs and sorting accuracy.
[0027] In step S2, as shown in Figure 1, gas G is compressed, the flow controller 4 is adjusted so that the pressure of gas G indicated by the pressure gauge 5 becomes a predetermined pressure, and the flow rate of gas G discharged from the multi-tube reactor 7 is measured by the flow meter 6. Alternatively, instead of measuring the flow rate of gas G, the flow controller 4 may be adjusted so that the flow rate of gas G indicated by the flow meter 6 becomes a predetermined flow rate, and the pressure of the adjusted gas G may be measured by the pressure gauge 5. Similar results can be obtained using this method as well. Therefore, the characteristic value may include at least one of the flow rate and differential pressure.
[0028] In step S3, a representative value of the characteristic value is calculated. The representative value may be the mean, median, or mode. Alternatively, instead of calculating a representative value of the characteristic value, the characteristic values of some of the reaction tubes 8 may be measured together in step S2. In such cases, it is not necessary to calculate a representative value of the characteristic value in step S3.
[0029] In step S4, the packing state of the catalyst 9 in the reaction tube 8 is determined based on the representative values of the calculated characteristic values. Specifically, it is determined whether the representative values of some of the reaction tubes 8 are outside the range of the first threshold. The first threshold is, for example, the upper limit specification value S specified in JIS Z9003-1979. U and lower specification limit S L It may contain [something]. If the representative value is within the range of the first threshold, the packing state of catalyst 9 within the lot is determined to be acceptable, and the process proceeds to step S8. On the other hand, if the representative value is outside the range of the first threshold, the process proceeds to step S5.
[0030] In step S5, the characteristic values of each reaction tube 8 included in the target lot are measured. The measurement of characteristic values can be performed in the same manner as in step S2.
[0031] In step S6, it is determined whether the characteristic value of each reaction tube 8 included in the target lot is within the range of the second threshold. The second threshold may be wider than the range of the first threshold. The second threshold is, for example, the upper limit acceptance value X (bar) specified in JIS Z9003-1979. Uand the lower limit of the passing grade X (bar) L It may also contain. If each characteristic value of the reaction tube 8 is within the range of the second threshold, the packing state of the catalyst 9 in the reaction tube 8 within the target lot is determined to be acceptable, and the process proceeds to step S8. On the other hand, if each characteristic value of the reaction tube 8 is outside the range of the second threshold, the reaction tube 8 that was outside the range of the second threshold is determined to be unacceptable, and the process proceeds to step S7.
[0032] In step S7, the packing state of the catalyst 9 in the reaction tube 8, which was outside the range of the second threshold, is adjusted. The method for adjusting the packing state of the catalyst 9 is not particularly limited. For example, if the flow rate of gas through the reaction tube 8 is low, some of the catalyst 9 packed in the reaction tube 8 may be removed, and if the flow rate of gas through the reaction tube 8 is high, the amount of catalyst 9 packed in the reaction tube 8 may be increased.
[0033] In step S8, it is confirmed whether the filling state of catalyst 9 has been determined for all lots. If there are any undetermined lots, the process returns to step S2 to determine the filling state of those lots. Once the filling state of catalyst 9 has been determined for all lots, the process is terminated. This step does not need to be performed if there is only one lot, for example.
[0034] The filling state determination method according to this embodiment can determine the filling state of the catalyst 9. The filling state may be determined before or after the start of use of the multi-tube reactor 7. That is, the catalyst 9 may be unused or used. In the filling state determination method according to this embodiment, the filling state of the catalyst 9 may be determined immediately after the catalyst 9 is filled.
[0035] As described above, the packing state determination method according to this embodiment is a method for determining the packing state of catalyst 9 packed in each of the multiple reaction tubes 8 in a multi-tube reactor 7 including a plurality of reaction tubes 8. In this method, gas G is flowed through some of the reaction tubes 8 among the plurality of reaction tubes 8 packed with catalyst 9, and characteristic values including at least one of the flow rate and differential pressure of the gas G flowing through some of the reaction tubes 8 are measured. In this method, the packing state of catalyst 9 in the reaction tubes 8 is determined based on representative values of the characteristic values.
[0036] According to the filling state determination method of this embodiment, the filling state of the catalyst 9 can be efficiently determined without measuring the characteristic values of each of the reaction tubes 8, by determining the filling state of the catalyst 9 based on representative values of the characteristic values. Therefore, the working time required to fill the catalyst 9 can be shortened while ensuring the filling quality of the catalyst 9.
[0037] The method for determining the packing state may involve calculating a representative value of the characteristic value and determining the packing state of the catalyst 9 based on the calculated representative value of the characteristic value. With this method, the representative value can be calculated from the characteristic value. Therefore, the characteristic value of the reaction tube 8 can be measured using a simple device.
[0038] Multiple reaction tubes 8 may be divided into multiple lots, and one of these lots, the target lot, may contain some of the reaction tubes 8 whose characteristic values are measured. The packing state determination method may measure the characteristic values of each reaction tube 8 included in the target lot if the representative value of some of the reaction tubes 8 is outside the range of the first threshold. The packing state determination method may then determine whether the characteristic values of each reaction tube 8 included in the target lot are within the range of the second threshold. With this method, even if the number of reaction tubes 8 in the multi-tube reactor 7 is large, such as 100 or more or 500 or more, the amount of work and sorting accuracy can be adjusted by determining the size of the lot and the number of reaction tubes 8 to be measured.
[0039] The representative value may be an average value, a median value, or a mode value. These representative values can be easily calculated. Therefore, by using these representative values, the state of the catalyst 9 in the reaction tube 8 can be grasped more easily.
[0040] The catalyst 9 may produce hydrocarbons. Hydrocarbons are widely used as energy sources and raw materials for chemical products, etc. Therefore, by efficiently determining the filling state of the catalyst 9, such hydrocarbons can be efficiently produced.
[0041] The catalyst 9 may be unused. By determining the filling state of such a catalyst 9, reaction products can be produced while maintaining an appropriate filling state within a proper range from the time of production.
[0042] Next, a specific example will be used to further explain the method for determining the filling state of the catalyst in more detail.
[0043] First, the catalyst powder divided into specified amounts was filled into all 170 reaction tubes of the multitubular reactor. Next, the characteristic value x in all the reaction tubes of the multitubular reactor was measured respectively. Then, the average value of these characteristic values x was calculated as the population mean, and the standard deviation was calculated as the population standard deviation (however, those outside the range of the upper limit acceptance determination value X(bar) U and the lower limit acceptance determination value X(bar) L were excluded). In this example, the characteristic value x was the flow rate value of the gas flowing in the reaction tube. As a result, the population mean was 1.8621 m 3 / hour, and the population standard deviation was 0.0646 m 3 / hour.
[0044] Next, for the multitubular reactor, in accordance with "6. Implementation of Inspection When Guaranteeing the Lot Nonconforming Rate" in JIS Z9003 - 1979, the upper limit acceptance determination value X(bar) U and the lower limit acceptance determination value X(bar) L were obtained as follows. Specifically, the upper limit acceptance determination value X(bar) U and the lower limit acceptance determination value X(bar) LThis was calculated based on the following formulas (1) and (2).
[0045] X(bar) U =S U -kσ (1) X(bar) L =S L +kσ (2)
[0046] Note that in the above formula (1), S U This is the upper specification limit, set at +10% of the population mean. In this example, the population mean is 1.8621m 3 It is / hour. Therefore, the upper specification limit S U This is 2.04831. In the above formula (2), S L This is the lower specification limit, set at -10% of the population mean. In this example, the population mean is 1.8621m 3 It is / time. Therefore, the lower specification limit S L This is 1.67589. In formulas (1) and (2) above, k is a coefficient, which was read as 1.13 from Appendix 2 of JIS Z9003-1979. In formulas (1) and (2) above, σ is the lot standard deviation, and was used as the population standard deviation. In this example, the population standard deviation is 0.0646m 3 The value is per hour. Therefore, the standard deviation σ of the lot is 0.0646m. 3 It is time.
[0047] The upper specification value S is applied to formulas (1) and (2) above. U Lower specification limit S L By substituting the coefficient k and the standard deviation σ of the lot, the upper limit of the acceptance criteria X (bar) can be obtained. U and the lower limit of the passing grade X (bar) L The following was calculated: The upper limit of the pass / fail judgment value X(bar) U It is 1.9753, and X(bar) L The value was 1.7489.
[0048] According to Appendix 2 of JIS Z9003-1979, the upper limit P0 for the defect rate of lots that should ideally be accepted was 2.50%, and the lower limit P1 for the defect rate of lots that should ideally be rejected was 31.50%. In addition, as commonly used values, producer risk α was set to 0.05 and consumer risk β to 0.1.
[0049] Based on the results of preliminary tests, and considering the balance between labor costs and sorting accuracy, the reaction tubes of the multi-tube reactor were divided into 10 lots in this example, with each lot having a size N of 16-18. The flow rates of the reaction tubes of the first and second lots are shown in Figures 5 and 6 for reference.
[0050] As shown in Figure 5, in the first lot, the flow rates of reaction tubes No. 2-4 and 7-17 were within the upper limit specification value S. U and lower specification limit S L The flow rates were within the first threshold range. On the other hand, the flow rates of reaction tubes No. 1, 5, and 6 were outside the first threshold range. However, the average flow rate of, for example, four reaction tubes randomly selected from the first lot is expected to be within the first threshold range. If the average value is within the first threshold range, the reaction tubes from the first lot can be judged as acceptable.
[0051] On the other hand, as shown in Figure 6, in the second lot, the flow rates of reaction tubes No. 1, 2, 4, 6, 12, and 14 were at the upper limit specification value S. U and lower specification limit S L The flow rates were within the first threshold range. On the other hand, the flow rates of reaction tubes No. 3, 5, 7-11, 13, and 15-16 were outside the first threshold range. Therefore, the average value of the flow rates of, for example, four reaction tubes randomly selected from the second lot is considered to be outside the first threshold range. If the average value is outside the first threshold range, the reaction tubes in the second lot are judged to be unacceptable. In this case, the flow rate of each reaction tube in the second lot is within the upper limit of the acceptance threshold value X (bar). U and the lower limit of the passing grade X (bar) LThe reaction tubes are then checked to determine if they are within the second threshold range. Reaction tubes No. 1-4, 6-8, and 12-15 of the second lot are within the second threshold range. Therefore, these reaction tubes are judged to be acceptable, and no special measures are taken; the catalyst filling state is left as is. On the other hand, reaction tubes No. 5, 9, 10, 11, and 16 of the second lot are outside the second threshold range. Therefore, these reaction tubes are judged to be unacceptable, and the catalyst filling state is adjusted.
[0052] By using the catalyst packing state determination method described above, the catalyst packing state can be efficiently determined for each lot, without having to measure the characteristic values of all the reaction tubes in a multi-tube reactor.
[0053] Although several embodiments have been described, it is possible to modify or transform the embodiments based on the above disclosure. All components of the above embodiments, and all features described in the claims, may be taken individually and combined, provided that they do not conflict with each other.
[0054] This disclosure can contribute, for example, to United Nations Sustainable Development Goal (SDG) 7, "Ensure access to affordable, reliable, sustainable, and modern energy for all," and Goal 13, "Take urgent action to combat climate change and its impacts." [Explanation of Symbols]
[0055] 7. Multitubular reactor 8 reaction tubes 9 Catalyst
Claims
1. A method for determining the packing state of catalysts packed in each of the multiple reaction tubes in a multi-tube reactor including multiple reaction tubes, By flowing gas through some of the plurality of reaction tubes filled with the catalyst, characteristic values including at least one of the flow rate and differential pressure of the gas flowing through the some reaction tubes are measured. A method for determining the packing state of the catalyst in the reaction tube, based on representative values of the aforementioned characteristic values.
2. The representative value of the aforementioned characteristic value is calculated, A method for determining the filling state of the catalyst according to claim 1, wherein the filling state of the catalyst is determined based on the representative value of the calculated characteristic value.
3. The plurality of reaction tubes are divided into multiple lots, and one of the multiple lots, which is the target lot, contains some of the reaction tubes whose characteristic values are measured. If the representative value of some of the reaction tubes is outside the range of the first threshold, the characteristic value of each of the reaction tubes included in the target lot is measured. The method for determining the filling state according to claim 1, which determines whether the characteristic value of each of the reaction tubes included in the target lot is within the range of a second threshold.
4. The method for determining the filling state according to claim 1 or 2, wherein the representative value is the mean, median, or mode.
5. The method for determining the packing state according to claim 1 or 2, wherein the catalyst generates hydrocarbons.
6. The method for determining the filling state according to claim 1 or 2, wherein the catalyst is unused.