Reactor and reaction device

Abstract

To provide a reactor and a reaction device which can simply estimate temperature distribution.SOLUTION: A reactor includes a hollow body, a plurality of reaction pipes which are arranged along a center line of the body in the body, a catalyst stored in the reaction pipes, and thermometers for detecting the temperature of the catalyst. When a center of gravity of a figure similar to the shape of the body is made to coincide with a center line in a cross section vertical to the center line, the thermometers are arranged one by one in at least the two reaction pipes out of the reaction pipes crossing the periphery of the figure, and positions where the thermometers detect the temperature of the catalyst are different from each other in a length direction of a part where the catalyst is arranged in the reaction pipes.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a multi-tubular reactor and a reactor. [Background technology]

[0002] In a multi-tubular reactor in which a heat transfer medium is made to flow around a reaction tube containing a catalyst to remove or supply reaction heat, the prior art disclosed in Patent Document 1 detects temperatures of parts of reaction tubes constituting a group of reaction tubes arranged adjacent to each other to grasp the overall temperature distribution. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2005 / 005037 Summary of the Invention [Problem to be solved by the invention]

[0004] In the prior art, it is necessary to detect the temperatures of many reaction tubes in order to grasp the temperature distribution, which is cumbersome.

[0005] The present invention has been made to solve this problem, and has an object to provide a reactor and a reaction apparatus that can easily estimate the temperature distribution. [Means for solving the problem]

[0006] To achieve this object, a first aspect of the present invention is a reactor comprising a hollow shell extending in a longitudinal direction, a plurality of reaction tubes arranged in the shell so as to extend along a center line of the shell, a catalyst accommodated in the reaction tube, and a plurality of thermometers for detecting a temperature of the catalyst, wherein the thermometers are arranged at at least two reaction tubes intersecting a periphery of a figure similar to the outline of the shell in a cross section perpendicular to the center line, the figure having a center of gravity coinciding with the center line and a distance between the outline of the shell and a periphery of the figure being equal, and the positions at which the plurality of thermometers detect the temperatures of the catalyst are different from each other in a longitudinal direction.

[0007] In the second embodiment, in the first embodiment, a distance between center lines of adjacent reaction tubes is 1.5 times or more the thickness of the reaction tubes.

[0008] In a third aspect, in the first or second aspect, the positions at which the plurality of thermometers detect the temperature of the catalyst include a first position between a center of the catalyst in a longitudinal direction and an inlet of the reaction tube, and a second position between the center of the catalyst in the longitudinal direction and an outlet of the reaction tube.

[0009] In the fourth embodiment, in any one of the first and second embodiments, a raw material gas flows from an inlet to an outlet of a reaction tube, and a product gas is obtained from the outlet by an exothermic chemical reaction.

[0010] A fifth embodiment is the fourth embodiment, wherein the product gas comprises a hydrocarbon.

[0011] In a sixth embodiment, in the fifth embodiment, the hydrocarbon has 1 to 10 carbon atoms.

[0012] A seventh aspect is a reaction apparatus comprising the reactor according to any one of the third to sixth aspects, and an estimation unit that estimates the position where the catalyst temperature is highest from the result detected by the thermometer. Effect of the Invention

[0013] According to the present invention, when the center of gravity of a figure similar to the outline of the body is aligned with the center line in a cross section perpendicular to the center line of the body extending in the longitudinal direction, one thermometer is disposed for at least two reaction tubes among the reaction tubes intersecting the circumference of the figure. Since the positions at which the thermometers detect the catalyst temperature are different in the longitudinal direction, the temperature distribution can be easily estimated. [Brief description of the drawings]

[0014] [Figure 1] FIG. 2 is a cross-sectional view of a reactor in one embodiment. [Diagram 2] 2(a) is a cross-sectional view of the reactor taken along line IIa-IIa in FIG. 1, and (b) is a cross-sectional view of adjacent reaction tubes. [Diagram 3] FIG. 2 is a piping diagram of a reaction apparatus. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. Fig. 1 is a cross-sectional view including a center line C of a body 11 of a reactor 10 in one embodiment. The reactor 10 includes a hollow body 11 and a plurality of reaction tubes 12 arranged in the body 11 along the center line C of the body 11. In Fig. 1, the number and diameters of the reaction tubes 12 are illustrated diagrammatically. A catalyst 13 is filled in the reaction tubes 12.

[0016] The catalyst 13 may be any suitable catalyst for various chemical reactions without any restrictions. Examples of the catalyst 13 include metal particles including one or more of Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, Ir, Pt, and Au, and semiconductor particles such as CuO, ZnO, V2O5, V2O3, Fe2O3, TiO2, CdO, NiO, CoO, MoO3, Cu2O, Cr2O3, MnO, FeO, and Ag2O. The catalyst 13 may be a porous carrier having metal or semiconductor particles fixed thereon. Examples of the carrier include oxides including one or more of alumina, silica, magnesia, titania, zirconia, niobia, silica-alumina, zeolite, and calcium phosphate. The reaction tube 12 is filled with the catalyst 13 so that the catalytic activities are approximately equal to each other.

[0017] The tube plates 14 arranged at both ends of the reaction tube 12 in the longitudinal direction fix the reaction tube 12 in the body 11 with a gap therebetween. The inlet 15 and outlet 16 of the reaction tube 12 are arranged near the tube plates 14. The raw material gas entering from the inlet 15 of the reaction tube 12 comes into contact with the catalyst 13 while passing through the reaction tube 12, and the reaction proceeds. The product gas after the catalytic reaction of the raw material gas goes out of the reaction tube 12 from the outlet 16. The type of catalytic reaction is not limited, but examples include a gas-phase oxidation reaction in which a hydrocarbon (raw material gas) is oxidized to obtain an oxide (product gas) such as ethylene oxide or acrylic acid, and a hydrogen addition reaction in which an oxocarbon (raw material gas) is converted into a hydrocarbon such as methane or a hydrocarbon-based substance (product gas) such as alcohol, ester, or aldehyde.

[0018] Baffles 17 are provided between the tube sheets 14. The heat transfer medium enters the body 11 from a medium inlet 18 provided near the outlet 16, flows around the reaction tubes 12 through the baffles 17, exchanges heat with the reaction tubes 12, and then exits the body 11 from a medium outlet 19 provided near the inlet 15. The heat transfer medium has the function of removing reaction heat from the reaction tubes 12 when the chemical reaction occurring in the reaction tubes 12 is an exothermic reaction, and has the function of supplying reaction heat to the reaction tubes 12 when the chemical reaction occurring in the reaction tubes 12 is an endothermic reaction.

[0019] A thermometer 20 for detecting the temperature of the catalyst 13 is disposed in the reaction tube 12. The thermometer 20 may be, for example, a thermocouple or a resistance thermometer, but is not limited thereto as long as it is industrially usable. The thermometer 20 is disposed in each of some of the reaction tubes 12 (four reaction tubes 12 in this embodiment) disposed in the body 11. The position at which the thermometer 20 detects the temperature of the catalyst 13 differs from one another in the longitudinal direction of the portion of the reaction tube 12 where the catalyst 13 is disposed.

[0020] In this embodiment, the temperature of the catalyst 13 is detected at four positions: a central position 21 at the center in the longitudinal direction, first positions 22 and 23 between the central position 21 and the inlet 15, and a second position 24 between the central position 21 and the outlet 16. The first positions 22 and 23 include a position 22 near the inlet 15 of the reaction tube 12 and a position 23 at half the distance between the central position 21 and the position 22. The first positions 22 and 23, the central position 21, and the second position 24 are provided at equal intervals. The positions and the number of positions at which the temperature of the catalyst 13 is detected are not limited to those described above. It is sufficient to detect the temperature at two or more positions necessary to estimate the temperature distribution of the reaction tube 12 in the flow direction of the raw material gas.

[0021] In this embodiment, the thermometer 20 is disposed in the reaction tube 12 and directly detects the temperature of the catalyst 13 in the reaction tube 12, but is not limited thereto. Since the catalyst 13 exchanges heat with the reaction tube 12 with which the heat transfer medium is in contact, the thermometer 20 may be disposed outside the reaction tube 12 so that the temperature of the catalyst 13 is indirectly detected by detecting the temperature of the outer surface of the reaction tube 12.

[0022] FIG. 2(a) is a cross-sectional view perpendicular to the center line C of the reactor 10 taken along line IIa-IIa in FIG. 1. In FIG. 2(a), the baffle 17 is omitted. The reaction tubes 12 are arranged parallel to the center line C of the body 11 with a gap between them. A figure 25 is a planar figure similar to the shape of the inner periphery of the body 11, and the center of gravity 26 is the geometric center of the figure 25. In this embodiment, the figure 25 is a circle, and the center of gravity 26 is the center of the circle, but this is not limited thereto. The outline of the cross section of the body 11 is appropriately set to an ellipse, a polygon, or the like. Therefore, the shape of the figure 25 and the position of the center of gravity 26 are appropriately determined according to the shape of the cross section of the body 11 perpendicular to the center line C.

[0023] When the figure 25 is arranged so that the center of gravity 26 of the figure 25 coincides with the center line C and the distance D3 between the contour of the body 11 and the circumference of the figure 25 is equal, the thermometer 20 (see FIG. 1 ) is arranged at least two of the reaction tubes 12 (four reaction tubes 12 in this embodiment) among the reaction tubes 12 intersecting the circumference of the figure 25. Since the figure 25 is a circle in this embodiment, the distance D3 becomes equal when the center of gravity 26 of the figure 25 coincides with the center line C. When the figure 25 is an ellipse or a polygon, the figure 25 is superimposed on the contour of the body 11 so that the distance D3 becomes equal.

[0024] Assuming that the temperature of the heat transfer medium around the reaction tube 12 intersecting the circumference of the figure 25 is almost uniform in the cross section perpendicular to the center line C of the body 11, the temperature distribution of the entire reaction tube 12 in the body 11 can be estimated by detecting a plurality of temperatures at different positions in the longitudinal direction of the reaction tube 12 intersecting the circumference of the figure 25. Since the number of the reaction tubes 12 to be detected can be reduced, the temperature distribution of the reaction tube 12 can be easily estimated.

[0025] It is more preferable that the thermometer 20 for detecting the temperature of the reaction tube 12 intersecting the circumference of the figure 25 is arranged so as to detect the temperature of the upper part (the reaction tube 12 and the catalyst 13) of the circumference of the figure 25. This is for improving the accuracy of estimating the temperature distribution of the reaction tube 12.

[0026] 2(b) is a cross-sectional view of adjacent reaction tubes 12. A distance D2 between center lines 27 of adjacent reaction tubes 12 is set to be 1.5 times or more the thickness D1 of the reaction tube 12. When the distance D2 is 1.5 times or more the thickness D1, depending on the flow rate of the heat transfer medium, the flow of the heat transfer medium around the reaction tube 12 and the heat transfer between the reaction tube 12 and the heat transfer medium can be prevented from being hindered, and therefore, the unevenness of the temperature distribution in the cross section of the body 11 can be reduced. This can reduce the deterioration of the accuracy of estimating the temperature distribution of the reaction tube 12.

[0027] FIG. 3 is a piping diagram of a reaction apparatus 30 including a reactor 10. Two pipes 31 and 34 are connected to the reactor 10. The pipe 31 is a pipe through which a first raw material gas is supplied, and a control valve 32 and a check valve 33 are arranged in this order from upstream to downstream. The pipe 34 is a pipe through which a second raw material gas is supplied, and a control valve 35 and a check valve 36 are arranged in this order from upstream to downstream. A gate valve 38 is arranged in a raw material gas pipe 37 where the pipes 31 and 34 join. The first and second raw material gases are set to an optimal mixing ratio through the control valves 32 and 35, respectively, and a mixed gas (raw material gas) obtained by mixing the two raw material gases flows through the raw material gas pipe 37 through the gate valve 38.

[0028] A heat exchanger 39 is connected downstream of a gate valve 38 disposed in the raw gas pipe 37. The heat exchanger 39 exchanges heat between the low-temperature raw gas flowing through the raw gas pipe 37 and the high-temperature produced gas flowing through a produced gas pipe 40 (described later). There are no limitations on the heat exchanger 39, but a plate-type heat exchanger that exchanges heat by alternately flowing the raw gas and the produced gas between stacked heat transfer plates is preferred because of its high heat transfer coefficient.

[0029] The upstream end of the product gas pipe 40 is connected to the outlet of the reactor 10. The downstream end of the raw material gas pipe 37 is connected to the inlet of the reactor 10. The catalyst 13 (see FIG. 1) lowers the activation energy of the chemical reaction of the raw material gas entering from the inlet of the reactor 10, making it easier for the chemical reaction to proceed. The product gas containing the products of the chemical reaction enters the product gas pipe 40 from the outlet of the reactor 10.

[0030] In this embodiment, a case will be described in which the first raw material gas is hydrogen, and the second raw material gas is an oxocarbon such as carbon monoxide or carbon dioxide. The reactor 10 is set at a moderate pressure, and generates a product gas containing a hydrocarbon such as methane, ethane, or propane by an exothermic reaction. The product gas is cooled by a condenser 41 connected to a product gas pipe 40, and separated into a gas containing the hydrocarbon and water. For superior versatility, the carbon number of the hydrocarbon is preferably 1 to 10. The gas containing the hydrocarbon may contain a portion of the raw material gas.

[0031] The heat transfer medium that enters the body 11 from the medium inlet 18 provided near the outlet of the reactor 10 exchanges heat with the reaction tubes 12 and exits the body 11 from the medium outlet 19 provided near the inlet of the reactor 10. This allows the heat transfer medium to remove the heat of reaction. Since the heat transfer medium flows in the opposite direction to the flow of the raw material gas in the reaction tubes 12, the logarithmic mean temperature difference between the reaction tubes 12 and the heat transfer medium can be made larger than when the raw material gas and the heat transfer medium flow in the same direction. Therefore, the amount of heat exchange between the reaction tubes 12 and the heat transfer medium can be made larger.

[0032] A heater 42 for heating the raw gas flowing through the raw gas pipe 37 is disposed in the raw gas pipe 37. The heater 42 may be, for example, one that uses gas combustion heat or electricity to heat a heat source to heat the raw gas pipe 37, one that uses induction heating, or one that uses exhaust heat from the reactor 10. In particular, the heater 42 that uses electricity to heat a heat source to heat the raw gas pipe 37 is preferred because of its high accuracy of temperature control.

[0033] When the raw material gas enters the reactor 10, a chemical reaction progresses while the raw material gas passes through the reaction tube 12, and a product gas comes out from the outlet of the reactor 10. Since the chemical reaction occurring in the reaction tube 12 is accompanied by heat generation, the catalyst 13 is heated by the reaction heat. The thermometer 20 detects the temperature of the catalyst 13, and the estimation unit 43 acquires the result detected by the thermometer 20.

[0034] The estimation unit 43 includes a CPU, a ROM, a RAM, and a backup RAM (none of which are shown). The ROM is a non-volatile memory that stores the programs executed by the CPU. The CPU executes calculation processing based on the programs stored in the ROM. The RAM is a memory that temporarily stores the calculation results of the CPU, data input from each sensor, etc. The backup RAM is a non-volatile memory that stores data to be saved, etc.

[0035] The estimation unit 43 estimates a temperature distribution 44 of the entire reaction tube 12 from the temperatures of a part of the reaction tube 12 detected by the thermometer 20. The temperature distribution 44 is created based on the temperatures detected at the positions 21, 22, 23, and 24, and is a diagram in which the vertical axis represents the longitudinal distance from the inlet 15 (see FIG. 1) of the reaction tube 12 in the part where the catalyst 13 is disposed in the reaction tube 12, and the horizontal axis represents the temperature of the catalyst 13.

[0036] The estimation unit 43 may estimate the temperature distribution 44 based only on the temperature detected by the thermometer 20, or may estimate the temperature distribution 44 based on knowledge (data) previously obtained by a thermal environment simulation or the like in addition to the temperature detected by the thermometer 20. The data from the thermal environment simulation or the like is stored in the ROM of the estimation unit 43.

[0037] The chemical reaction of obtaining hydrocarbons by the addition of hydrogen to oxocarbons generates a large amount of heat, and the reaction starts very quickly near the inlet 15 where the raw material gas entering the reaction tube 12 meets the catalyst 13. The start of this reaction heats up the catalyst 13, and a hot spot where the temperature of the catalyst 13 is the highest occurs near the inlet 15. Since the reaction products move downstream with the flow of the raw material gas, there are many reaction products near the outlet 16 of the reaction tube 12 (see Figure 1), and the reaction heat near the outlet 16 does not become very large.

[0038] The performance of the catalyst 13 gradually decreases with the operation of the reactor 30. This is the so-called deterioration of the catalyst 13. The deterioration of the catalyst 13, such as sintering, tends to occur around the hot spot where the catalyst 13 is exposed to high temperatures. As the deterioration of the catalyst 13 progresses, the reaction in the reaction tube 12 starts slowly, and the position of the hot spot gradually moves toward the outlet 16. Therefore, in the temperature distribution 44 after the catalyst 13 has deteriorated, the temperature at the positions 22 and 23 is lower and the temperature at the position 21 is higher than the temperature distribution 44 before the catalyst 13 deteriorated. The deterioration state of the catalyst 13 is diagnosed based on the change in the temperature distribution 44, and the catalyst 13 is replaced as necessary, thereby making it possible to produce hydrocarbons stably and efficiently.

[0039] Since the thermometer 20 detects the temperature on the side (first positions 22, 23) closer to the inlet 15 than the central position 21 of the reaction tube 12 more than the temperature on the side (second position 24) closer to the outlet 16 than the central position 21 of the reaction tube 12, the deterioration of the catalyst 13 in the exothermic reaction can be estimated with a small number of thermometers 20. Since the temperatures of the first positions 22, 23 and the second position 24 of the reaction tube 12 are detected, the accuracy of estimating the entire temperature distribution in the longitudinal direction of the reaction tube 12 can be improved compared to the case where only the temperatures of the first positions 22, 23 are detected without detecting the temperature of the second position 24. By increasing the accuracy of estimating the entire temperature distribution in the longitudinal direction of the reaction tube 12, the operating state of the reactor 10 can be easily optimized.

[0040] Since the reaction occurring in the reactor 10 is an exothermic reaction, once a chemical reaction starts near the inlet 15 of the reaction tube 12, the reaction proceeds spontaneously. In order for the chemical reaction to start near the inlet 15 of the reaction tube 12, it is advantageous for the raw material gas entering the reactor 10 to have a high temperature, for example, a temperature of 300-350°C is preferable. Since the temperature of the raw material gas flowing through the raw material gas pipe 37 is lower than the temperature of the product gas flowing through the product gas pipe 40, the raw material gas is heated by the product gas in the heat exchanger 39. Since the temperature of the raw material gas entering the reactor 10 can be increased, the reaction efficiency can be improved.

[0041] The product gas discharged from the reactor 10 is cooled by the feed gas in the heat exchanger 39. Since the condenser 41 is disposed downstream of the heat exchanger 39 in the flow of the product gas, the energy input to the condenser 41 for cooling the product gas can be reduced.

[0042] It is preferable to flow the raw material gas in the heat exchanger 39 in the opposite direction to the flow of the produced gas in the heat exchanger 39. This is because the logarithmic mean temperature difference between the raw material gas and the produced gas in the heat exchanger 39 can be made larger than when the raw material gas and the produced gas in the heat exchanger 39 flow in the same direction. This makes it possible to increase the amount of heat exchanged in the heat exchanger 39.

[0043] Since the heater 42 is disposed in the raw gas pipe 37, the temperature of the raw gas entering the reactor 10 from the raw gas pipe 37 can be further increased by operating the heater 42. As a result, the reaction efficiency can be further improved.

[0044] The present invention has been described above based on an embodiment, but the present invention is not limited to the above embodiment, and it can be easily inferred that various improvements and modifications are possible within the scope of the present invention without departing from the spirit of the present invention.

[0045] In the embodiment, when the center of gravity 25 of the figure 25 is aligned with the center line C of the body 11 in the cross section perpendicular to the center line C, the thermometers 20 are arranged in four of the reaction tubes 12 that intersect with the circumference of the figure 25. However, the present invention is not limited to this. The number (at least two) of the reaction tubes 12 that are arranged with the thermometers 20 among the reaction tubes 12 that intersect with the circumference of the figure 25 is appropriately set.

[0046] In the embodiment, a case has been described in which one figure 25 similar to the shape of the body 11 is drawn on the cross section perpendicular to the center line C, and a reaction tube 12 intersecting with the circumference of the figure 25 is selected, but the present invention is not necessarily limited to this. It is of course possible to draw two or more figures 25 different in size similar to the shape of the body 11 on the cross section perpendicular to the center line C, and select a reaction tube 12 intersecting with the circumference of these figures 25. When two or more figures 25 different in size are drawn, a reaction tube 12 intersecting with the circumference of the figure 25 is selected for each figure 25 different in size, and at least two thermometers 20 are arranged for each figure 25. In this case, it is preferable because the temperature distribution in the radial direction of the body 11 can be taken into consideration.

[0047] In the embodiment, the case where the temperatures at the first positions 22, 23 and the second position 24 of the reaction tube 12 are detected has been described, but the present invention is not necessarily limited to this. It is of course possible to omit the detection of the temperature at the second position 24. This is because a hot spot where the catalyst 13 is exposed to high temperatures usually appears at the first position from the central position 21 to the inlet 15, and therefore the deterioration of the catalyst 13 can be estimated by detecting the temperature at the first position and estimating the temperature distribution.

[0048] In the embodiment, the case where the temperature is detected at two first positions 22, 23 between the inlet 15 and the central position 21 of the reaction tube 12 has been described, but the present invention is not necessarily limited to this. The number of first positions for detecting the temperature between the inlet 15 and the central position 21 of the reaction tube 12 may be any number. Similarly, the number of second positions for detecting the temperature between the central position 21 and the outlet 16 of the reaction tube 12 is not limited to one, and may be any number.

[0049] In the embodiment, the heat exchanger 39 and the heater 42 are disposed in the raw material gas pipe 37, but the present invention is not limited to this. It is of course possible to omit the heat exchanger 39 and the heater 42.

[0050] In the embodiment, the heat exchanger 39, the medium inlet 18, and the medium outlet 19 are set so that the high-temperature fluid and the low-temperature fluid flow in countercurrent to each other, but this is not necessarily limited to this. It is of course possible to set the heat exchanger 39, the medium inlet 18, and the medium outlet 19 so that the high-temperature fluid and the low-temperature fluid flow in the same direction. [Explanation of symbols]

[0051] 10. Reactor 11 Torso 12 Reaction tube 15 Entrance 16 Exit 20 thermometer 22,23 1st position 24 2nd position 25 Shapes 26 Center of gravity 27 Reactor tube centerline 30 Reactor 43 Estimation part C Center line of the torso D1 Reaction tube size D2 Distance between the center lines of the reaction tubes

Claims

1. A hollow body extending in a longitudinal direction; A plurality of reaction tubes are disposed in the shell so as to extend along a center line of the shell; A catalyst contained in the reaction tube; A reactor comprising: a plurality of thermometers for detecting the temperature of the catalyst; the thermometers are arranged on at least two of the reaction tubes intersecting a circumference of a figure similar to a shape of an outline of the body, in a cross section perpendicular to the center line, such that a center of gravity of the figure coincides with the center line and a distance between the outline of the body and a circumference of the figure is equal; The positions at which the plurality of thermometers detect the temperatures of the catalyst are different from one another in the longitudinal direction of the reactor.

2. 2. The reactor according to claim 1, wherein a distance between center lines of adjacent reaction tubes among the reaction tubes is 1.5 times or more a thickness of the reaction tube.

3. 2. The reactor according to claim 1, wherein the positions at which the plurality of thermometers detect the temperature of the catalyst include a first position between a center of the catalyst in the longitudinal direction and an inlet of the reaction tube, and a second position between a center of the catalyst in the longitudinal direction and an outlet of the reaction tube.

4. 4. The reactor according to claim 1, wherein a raw material gas flows from an inlet to an outlet of the reaction tube, and a product gas is obtained from the outlet by an exothermic chemical reaction.

5. 5. The reactor of claim 4 wherein said product gas comprises a hydrocarbon.

6. 6. The reactor according to claim 5, wherein the hydrocarbon has 1 to 10 carbon atoms.

7. The reactor of claim 4; and an estimation unit that estimates a position where the temperature of the catalyst is the highest based on the result detected by the thermometer.

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