Multiple pipe-type reaction vessel

Abstract

To provide a multiple pipe-type reaction vessel excellent in cooling efficiency, while easy to exchange catalysts to be loaded.SOLUTION: A multiple pipe-type reaction vessel 1 includes: a catalyst fastening inner cooling pipe 3 configured to allow a cooling fluid to flow therein with a porous catalyst layer 9 fastened on an outer peripheral face; a reaction gas flow tube 5 with the catalyst fastening inner cooling pipe 3 removably inserted, and configured to allow a reaction gas to flow inside; and an outer cooling container 7 disposed on an outer periphery of the reaction gas flow tube 5, and configured to allow a cooling fluid to flow therein to cool the outer peripheral face of the reaction gas flow tube 5.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a reactor vessel having a catalyst-filled vessel through which a reaction gas flows and which is filled with a catalyst, and in particular to a multi-tube reactor vessel in which the reactor vessel has multiple tubes. [Background technology]

[0002] Catalytic reactions are often exothermic, and as the reactor scale increases, there is a concern that abnormal heat generation within the catalyst bed may cause the reaction to go out of control or damage the catalyst and equipment, so a cooling mechanism is important. For example, Patent Document 1 discloses a method in which a heat transfer tube through which a refrigerant flows is provided in a catalyst packed bed to cool the packed bed.

[0003] In addition, the activity of the catalyst gradually decreases due to poisoning by impurities contained in the raw materials, adhesion of products to the catalyst surface, etc. For this reason, the catalyst packed in the reactor is generally replaced periodically.

[0004] As a method for replacing a catalyst, for example, Patent Document 2 discloses a technique in which the tip of a double pipe is cut open, a vacuum pump hose is inserted to suck out the filler, and the pipe is refilled and then welded shut. Moreover, Patent Document 3 discloses a method in which a fluid is fed into a tube filled with a catalyst to flush out the filler. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2003-229147 A [Patent Document 2] Japanese Patent Application Publication No. 10-328555 [Patent Document 3] Japanese Patent Publication No. 60-71036 Summary of the Invention [Problem to be solved by the invention]

[0006] Regarding the cooling mechanism, the method of Patent Document 1 has a problem in that the cooling efficiency is good in areas close to the heat transfer tubes in the packed bed, but is poor in areas away from the heat transfer tubes, such as near the wall of the packed container.

[0007] In addition, in the method of Patent Document 2, the replacement of the catalyst requires the use of a vacuum pump to suck out the catalyst. In addition, since the catalyst is sucked up, the catalyst may fall due to the effect of gravity, making it difficult to recover all of it. Furthermore, in Patent Document 2, the container must be cut open prior to recovery of the catalyst, and the cut portion must be welded shut after filling, which is problematic in terms of labor and cost.

[0008] Furthermore, the method of Patent Document 3 has a problem in that it requires power to transport the fluid. In addition, when the filler is pushed away, depending on the shape of the container, the filler may be structurally trapped, making it impossible to recover the entire amount.

[0009] The present invention has been made to solve the above problems, and has an object to provide a multi-tube reaction vessel which is excellent in cooling efficiency and in which the catalyst packed therein can be easily replaced. [Means for solving the problem]

[0010] (1) The multi-tube reaction vessel according to the present invention is characterized in that it comprises: a catalyst-fixed inner cooling pipe through which a cooling fluid flows and which has a porous catalyst layer fixed to its outer peripheral surface; a reaction gas flow pipe into which the catalyst-fixed inner cooling pipe is removably inserted and through which a reaction gas flows; and an outer cooling vessel which is provided on the outer periphery of the reaction gas flow pipe and through which a cooling fluid flows to cool the outer peripheral surface of the reaction gas flow pipe.

[0011] (2) In addition, in the above-mentioned (1), the catalyst-attached inner cooling pipe is characterized in that the porous catalyst layer is attached to the outer peripheral surface of a metal pipe body via an intermediate layer, and the intermediate layer has a function of reducing the difference in thermal expansion coefficient between the porous catalyst layer and the pipe body.

[0012] (3) In the above (1) or (2), a baffle plate is provided which is disposed adjacent to the inner surface of the reaction gas flow pipe to prevent the porous catalyst layer from contacting the inner surface of the reaction gas flow pipe and which provides resistance to the flow of the reaction gas. Effect of the Invention

[0013] In the present invention, there are provided a catalyst-fixed inner cooling pipe through which a cooling fluid flows and which has a porous catalyst layer fixed to its outer peripheral surface, a reaction gas flow pipe into which the catalyst-fixed inner cooling pipe is removably inserted and through which a reaction gas flows, and an outer cooling vessel which is provided on the outer periphery of the reaction gas flow pipe and through which a cooling fluid flows to cool the outer surface of the reaction gas flow pipe, thereby making it possible to cool the porous catalyst layer from both the inside and the outside, resulting in excellent cooling efficiency. In addition, by removing the inner cooling pipe to which the catalyst is fixed, the porous catalyst layer can be removed at the same time, which provides excellent workability in catalyst replacement work. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is an explanatory diagram of a multi-tube reaction vessel according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view of the multi-tube reaction vessel shown in FIG. [Diagram 3] FIG. 2 is an explanatory diagram of a method for replacing a catalyst in the multi-tube reactor shown in FIG. [Figure 4] FIG. 2 is an explanatory diagram of an embodiment in which baffle plates are provided in the multi-tube reaction vessel shown in FIG. [Diagram 5] 5 is an explanatory diagram of the function when the baffle plate of FIG. 4 is provided. FIG. [Figure 6] FIG. 11 is an explanatory diagram of another embodiment of the baffle plate (part 1). [Figure 7] FIG. 2 is an explanatory diagram of another embodiment of the baffle plate (part 2). [Figure 8] FIG. 4 is an explanatory diagram of another embodiment of the baffle plate (part 3). [Figure 9] FIG. 2 is an explanatory view (part 1) of another aspect of a multi-tube reaction vessel according to an embodiment of the present invention. [Figure 10] FIG. 10 is an explanatory diagram of the operation of the multi-tube reaction vessel shown in FIG. [Figure 11] FIG. 2 is an explanatory view (part 2) of another aspect of a multi-tube reaction vessel according to an embodiment of the present invention. [Figure 12] FIG. 4 is an explanatory view (part 3) of another aspect of a multi-tube reaction vessel according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] A multi-tube reaction vessel 1 according to this embodiment includes a catalyst-fixed inner cooling tube 3, a reaction gas flow tube 5, and an outer cooling vessel 7, as shown in FIGS. Each component will be described in detail below.

[0016] <Catalyst fixed inner cooling pipe> The catalyst-fixed inner cooling pipe 3 has a cooling fluid flowing through it and has a porous catalyst layer 9 fixed to its outer peripheral surface, and the porous catalyst layer 9 is cooled from the inside by the cooling fluid flowing through it. The catalyst-fixed inner cooling pipe 3 is removably inserted into the reaction gas flow pipe 5, and in the inserted state, the space between the inner surface of the reaction gas flow pipe 5 and the outer surface of the catalyst-fixed inner cooling pipe 3, i.e., the space in which the porous catalyst layer 9 is arranged, becomes the space through which the reaction gas flows. A catalytic reaction takes place when the reaction gas passes through the porous catalyst layer 9 arranged in this space.

[0017] A cover member 11 is attached to the upper part of the catalyst-fixed inner cooling pipe 3, closing the upper end opening 5a (see Figure 3) of the reaction gas flow pipe 5 with the catalyst-fixed inner cooling pipe 3 inserted into the reaction gas flow pipe 5. In addition, the lower end of the catalyst-fixed inner cooling pipe 3 is adapted to close the lower end opening 5b (see FIG. 3) of the reaction gas flow pipe 5 in a state in which the catalyst-fixed inner cooling pipe 3 is inserted into the reaction gas flow pipe 5.

[0018] The porous catalyst layer 9 of the catalyst-attached inner cooling pipe 3 is formed as a film and attached (integrated) to the outer circumferential surface of the pipe. If the catalyst is a ceramic or carbon-based material such as alumina, silica, or zeolite, the film is formed directly by CVD or sputtering, or a precursor gel or slurry is dip-coated or wash-coated. After film formation, it is heated to adhere and attach. In addition, in the case of a zeolite material, it is possible to directly synthesize and form a membrane by hydrothermal synthesis.

[0019] Since the catalyst-fixed inner cooling pipe 3 is made of metal, it is preferable to provide an intermediate layer 13 made of a cermet or a binder material as shown in the enlarged view of FIG. 2 in order to reduce the difference in thermal expansion coefficient between the metal and the porous catalyst layer 9 (oxide carrier) and to ensure adhesion.

[0020] In this example, the cooling fluid flows in the catalyst-fixed inner cooling pipe 3 from the top to the bottom. Examples of cooling fluids include, but are not limited to, air, inert gas, water, seawater, ethylene glycol, and the like.

[0021] <Reaction gas flow tube> The catalyst-fixed inner cooling pipe 3 is removably inserted into the reaction gas flow pipe 5, and the reaction gas flows inside. A gas inlet 15 through which the reaction gas enters is provided at the bottom of the reaction gas flow pipe 5, and a gas outlet 17 through which the reaction gas (which may contain liquid) is discharged is provided at the top of the reaction gas flow pipe 5. Therefore, the flow of the reaction gas in the reaction gas flow pipe 5 is from bottom to top, opposite to the flow of the cooling fluid in the catalyst-fixed inner cooling pipe 3, and is a counterflow to the cooling fluid. Note that, as in this example, the reaction gas and the cooling fluid may be counterflowed, and in some cases, the reaction gas and the cooling fluid may be parallel flowed to preferentially cool the superheated part (gas inlet part).

[0022] <Outer cooling container> The outer cooling vessel 7 is provided on the outer periphery of the reaction gas flow pipe 5 and cools the outer periphery of the reaction gas flow pipe 5 by passing a cooling fluid therethrough. 1, the outer cooling vessel 7 of this embodiment is made of a cylinder having a larger diameter than the reaction gas flow pipe 5, and is provided with a cooling fluid inlet 19 on the upper side and a cooling fluid outlet 21 on the lower side. Therefore, the flow of the cooling fluid in the outer cooling vessel 7 is from the top to the bottom, similar to the catalyst fixing inner cooling pipe 3, and is a counterflow to the reaction gas.

[0023] In the multi-tube reaction vessel 1 configured as above, with the catalyst-fixed inner cooling pipe 3 inserted into the reaction gas flow pipe 5, a cooling fluid flows through the catalyst-fixed inner cooling pipe 3 and the outer cooling vessel 7. When the reaction gas flows through the reaction gas flow pipe 5, reaction heat is generated by a catalytic reaction as the reaction gas passes through the porous catalyst layer 9. This reaction heat is cooled from the inside by the cooling fluid flowing through the catalyst-fixed inner cooling pipe 3 and from the outside by the cooling fluid flowing through the outer cooling vessel 7.

[0024] In this way, in this embodiment, the heat of the catalytic reaction is cooled from both the inside and the outside, so the cooling efficiency is good. Also, by being able to cool from both the inside and the outside, it is possible to reduce the temperature unevenness of the catalyst and to suppress the occurrence of hot spots (a phenomenon in which a very small part of the packed bed generates abnormal heat).

[0025] In this embodiment, the catalyst-fixed inner cooling pipe 3 is disposed approximately at the center of the reaction gas flow pipe 5, so that cooling from the inside can be performed without bias. Similarly, the reaction gas flow pipe 5 is disposed approximately at the center of the outer cooling vessel 7, so that cooling from the outside can be performed without bias. However, since the present invention is characterized by cooling the porous catalyst layer 9 from the inside and the outside, it is not limited to the case where the catalyst-fixed inner cooling pipe 3 is disposed at the center of the reaction gas flow pipe 5, and it is also not limited to the case where the reaction gas flow pipe 5 is disposed at the center of the outer cooling vessel 7.

[0026] Furthermore, according to this embodiment, when it is time to replace the porous catalyst layer 9, the catalyst can be replaced by pulling out the catalyst-fixed inner cooling pipe 3 from the reaction gas flow pipe 5 and inserting a new catalyst-fixed inner cooling pipe 3, which makes the catalyst replacement work extremely easy.

[0027] As described above, according to this embodiment, the porous catalyst layer 9 can be cooled from both the inside and outside, and therefore the cooling efficiency is excellent. In addition, since the catalyst can be replaced by replacing the inner cooling pipe 3 to which the catalyst has adhered, the catalyst replacement work efficiency is excellent. In addition, since the catalyst is not discharged by gravity during replacement, the catalyst-fixed inner cooling pipe 3 can be placed horizontally, and the installation position of the multi-tube reaction vessel 1 is not limited.

[0028] As shown in FIG. 4, it is preferable to provide a baffle plate 23 on the outer periphery of the catalyst-fixed inner cooling pipe 3, which is disposed close to the inner surface of the reaction gas flow pipe 5 (dotted line in FIG. 4) to prevent the porous catalyst layer 9 (double-dotted line in FIG. 4) from contacting the inner surface of the reaction gas flow pipe 5 and to provide resistance to the flow of the reaction gas. In FIG. 4, the porous catalyst layer 9 is not shown. The baffle plate 23 shown in FIG. 4 is annular and has many gas passage holes 23a through which the reaction gas passes. By providing the gas passage holes 23a, the reaction gas is guided to the porous catalyst layer 9 side by the baffle plate 23, as shown in FIG. 5, and contact with the porous catalyst layer 9 is improved. The baffle plate 23 is also expected to have a holding effect on the porous catalyst layer 9.

[0029] The outer diameter of the baffle plate 23 is approximately equal to the inner diameter of the reaction gas flow pipe 5, and the outer diameter of the porous catalyst layer 9 is slightly smaller than the outer diameter of the baffle plate 23. The reason for this is as follows. By providing such a baffle plate 23, a small gap can be maintained between the porous catalyst layer 9 and the inner surface of the reaction gas flow pipe 5, thereby preventing the porous catalyst layer 9 from adhering to the inner surface of the reaction gas flow pipe 5 due to the catalytic reaction.

[0030] When it is time to replace the catalyst, the catalyst-fixed inner cooling pipe 3 is pulled out from the reaction gas flow pipe 5 and a new catalyst-fixed inner cooling pipe 3 is inserted. If the porous catalyst layer 9 hits the inner surface of the reaction gas flow pipe 5 during the pulling out or insertion, it will be damaged. However, since the outer peripheral end face of the baffle plate 23 protrudes beyond the porous catalyst layer 9, it is possible to prevent the porous catalyst layer 9 from hitting the inner surface of the reaction gas flow pipe 5. It is preferable to provide a plurality of baffle plates 23 in the axial direction of the catalyst-fixing inner cooling pipe 3 .

[0031] As another embodiment of the baffle plate 23, as shown in FIG. 6, semicircular rings divided in half in the circumferential direction may be provided at positions shifted in the axial direction.

[0032] Furthermore, if the outer peripheral end face of the baffle plate 23 abuts against the inner peripheral face of the reaction gas flow pipe 5, it is difficult to smoothly insert or remove the baffle plate 23, so it is preferable to provide a small gap. However, if there is a gap, the reaction gas will pass through the gap, so that a protrusion 25 that protrudes slightly around the entire circumference may be provided on the inner surface of the reaction gas flow pipe 5, and the outer peripheral end of the baffle plate 23 may be placed on the protrusion 25, as shown in Fig. 7. In this way, the gap is blocked by the protrusion 25 and the baffle plate 23, so that the reaction gas is guided to the porous catalyst layer 9 side, and the catalytic reaction can be carried out more reliably.

[0033] When a plurality of baffle plates 23 are provided, it is necessary to prevent interference between the baffle plates 23 and the protrusions 25 when inserting and removing the catalyst-fixed inner cooling pipe 3 into and from the reaction gas flow pipe 5. For this reason, for example, as shown in Fig. 8, the inner surface of the reaction gas flow pipe 5 may be tapered so that the diameter of the baffle plates 23 decreases downward, and the diameter of the baffle plates 23 on the lower side may be made smaller, so that the lower baffle plates 23 do not interfere with the upper protrusions 25.

[0034] In the above embodiment, the cover member 11 was required to close the upper end surface of the reaction gas flow pipe 5 in a state where the catalyst-fixed inner cooling pipe 3 was inserted into the reaction gas flow pipe 5. In this regard, as shown in Figures 9 and 10, the catalyst-fixed inner cooling pipe 3 has a tapered surface that narrows downward, and the upper part of the tapered surface is made slightly larger than the inner diameter of the reaction gas flow pipe 5 (see Figure 10), so that the upper end opening 5a of the reaction gas flow pipe 5 can be closed simply by inserting the catalyst-fixed inner cooling pipe 3 into the reaction gas flow pipe 5.

[0035] In addition, the porous catalyst layer 9 adhered to the tapered surface of the catalyst-adhered inner cooling pipe 3 is thinner at the top and thicker toward the bottom, as shown in Figures 9 and 10. Therefore, as shown in Figure 10, if the reaction gas is introduced from the top where the layer is thinner, the amount of catalyst in contact with the reaction gas at the top is small, so heat generation in the catalyst layer accompanying the catalytic reaction can be suppressed, and although the catalyst layer is thicker at the bottom, the amount of unreacted reaction gas is small, so heat generation is suppressed, and as a result, the temperature gradient between the upstream and downstream can be equalized.

[0036] In order to use the upper part of the catalyst-fixed inner cooling pipe 3 as a cover without providing the cover member 11, for example, as shown in FIG. 11, only the upper end part of the catalyst-fixed inner cooling pipe 3 may be tapered, and the porous catalyst layer 9 may be fixed to the straight pipe part below the tapered surface. In this embodiment, the thickness of the porous catalyst layer 9 is constant, and therefore the porous catalyst layer 9 can be easily controlled during its formation.

[0037] 12, only the upper end of the catalyst-fixed inner cooling pipe 3 may be enlarged in diameter to have a T-shaped cross section, and the lower surface of the part corresponding to the horizontal side of the T may be abutted against the upper end surface of the reaction gas flow pipe 5. In this embodiment, the catalyst-fixed inner cooling pipe 3 can be easily manufactured.

[0038] Furthermore, in the above example, one pair of a reaction gas flow pipe 5 and a catalyst-fixed inner cooling pipe 3 is provided for one outer cooling vessel 7, but the present invention is not limited to this, and multiple pairs of a reaction gas flow pipe 5 and a catalyst-fixed inner cooling pipe 3 may be provided for one outer cooling vessel 7. In this case, for example, when the same amount of porous catalyst layer 9 as that shown in FIG. 1 is used, the thickness of the porous catalyst layer 9 adhered to each catalyst-adhered inner cooling pipe 3 becomes thinner in this embodiment, and the cooling efficiency from the inside and outside is improved. [Explanation of symbols]

[0039] 1. Multi-tube reaction vessel 3 Catalyst fixed inner cooling pipe 5. Reaction gas flow tube 5a Top opening 5b Bottom opening 7 Outer cooling vessel 9 Porous catalyst layer 11 Cover member 13. Middle Class 15 Gas inlet 17 Gas exhaust port 19 Cooling fluid inlet 21 Cooling fluid outlet 23 Baffle plate 23a Gas passage hole 25 Protrusion

Claims

1. A multi-tube reaction vessel comprising: a catalyst-fixed inner cooling pipe through which a cooling fluid flows and which has a porous catalyst layer fixed to its outer peripheral surface; a reaction gas flow pipe into which the catalyst-fixed inner cooling pipe is removably inserted and through which a reaction gas flows; and an outer cooling vessel provided on the outer periphery of the reaction gas flow pipe and through which a cooling fluid flows to cool the outer peripheral surface of the reaction gas flow pipe.

2. 2. The multi-tube reaction vessel according to claim 1, wherein the catalyst-fixed inner cooling pipe is formed by fixing the porous catalyst layer to an outer circumferential surface of a metal pipe via an intermediate layer, and the intermediate layer has a function of reducing a difference in thermal expansion coefficient between the porous catalyst layer and the pipe.

3. 3. The multi-tube reaction vessel according to claim 1, further comprising a baffle plate disposed adjacent to an inner surface of the reaction gas flow pipe to prevent the porous catalyst layer from contacting the inner surface of the reaction gas flow pipe and to provide resistance to a flow of the reaction gas.

Images