JP3732080B2 - Catalytic gas phase oxidation reactor - Google Patents

Description

【００９９】
【発明の効果】
穴あき円板型邪魔板面積が支持しない反応管を配置したところ、軸流ポンプ電力を１／５．４に低減できた。しかも、選択率や目的生成物の収率を変化させずに軸流ポンプ電力を低減することができる。
【図面の簡単な説明】
【図１】 従来の多管式反応器を示す概略説明図である。
【図２】 本発明の反応器の穴あき円板型邪魔板、円板型邪魔板、反応管および空間部を示す図である。
【図３】 循環装置を有する反応器の熱媒の循環経路を示す図である。
【図４】 循環装置の一部から熱媒を取り出し、かつ循環装置に冷却後の熱媒を導入する反応器の概略図である。
【図５】 環状導管の開口列を示す図である。
【図６】 熱媒をダウンフローで流す場合の反応器の熱媒の流れを示す図である。
【図７】 上部管板部のガス排出口の配置を示す図である。
【図８】 本発明の２チャンバー式接触気相酸化反応器の縦断面の一例の説明図である。
【図９】 図８において、反応管内触媒層と中間管板との断面の拡大説明図である。
【符号の説明】
１…反応器シェル
２…穴あき円板型邪魔板
３…円板型邪魔板
４…反応管
４ａ…穴あき円板型邪魔板が支持しない反応管
４ｂ…円板型邪魔板が支持しない反応管
５，２１，２３…触媒
６ａ…下部管板
６ｂ…上部管板
７…タイロッド
８…中央管板
１０，１０ａ、１０ｂ…熱媒
１１ａ、１１ｂ…環状導管
１２…熱媒取り出し口
１３…熱媒排出ポット
１４…ノズル
１５、１６…ガス排出用導管
１７…ノズル
１８…受器
２２…不活性耐火物
２４…熱交換器
３０…循環装置
３１…熱媒循環口
３２、３２’…熱媒導入口
３３…撹拌翼
３４…熱媒排出口
３５…ポンプ
３６…ノズル
３７…仕切板
５０…原料供給口
５１…生成物排出口
φ１…穴あき円板型邪魔板穴径
φ２…円板型邪魔板径
φ３…反応器シェル内径
φ４…空間部径[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a multitubular reactor having a reaction tube that is not supported by a perforated disk-type baffle, and a method for producing (meth) acrylic acid or (meth) acrolein using the reactor.
[0002]
[Background Art and Problems to be Solved by the Invention]
The catalytic gas phase oxidation reaction using a multi-tubular reactor is a commonly used means for efficiently removing heat generated by the reaction. A multi-tubular reactor having a plurality of reaction tubes built in the reactor shell is used. The reaction tube is filled with a catalyst and a reaction raw material gas is supplied to perform a catalytic gas phase oxidation reaction. A heat medium that absorbs the heat of reaction is circulated to remove the generated heat of reaction.
[0003]
However, in the catalytic gas phase oxidation reaction using such a multi-tubular reactor, hot spots are likely to be generated on the raw material inlet side, and problems such as catalyst deterioration due to excessive exothermic reaction and reduction of the target product selectivity are problematic. It becomes.
[0004]
In order to solve such a problem, for example, Japanese Patent Publication No. 52-15272 discloses a multi-tubular reactor having a heat exchange medium circulating device, in which a baffle plate is arranged in a reactor shell. Is disclosed. It is disclosed that the presence of the baffle plate keeps the speed of the lateral flow in an area almost constant, which also keeps the heat transfer in one area constant. Specifically, the reactor shown in the publication has an upright reaction tube arranged in an annular shape in a reactor shell, and the upper and lower ends of the reaction tube are sealed and attached to a tube plate. In the reaction tube, a plurality of horizontal perforated disc-type baffles and disc-type baffles are alternately formed at the central and outer edges at intervals in the lateral direction. A tie rod and a spacer for attaching a disk-type baffle plate are provided in the center of the reactor shell.
[0005]
Here, FIG. 1 shows an outline of a conventional multi-tubular reaction tube containing a perforated disk-type baffle plate and a disk-type baffle plate. Tie rods and spacers 7 for connecting the baffle plates 3 are arranged. A perforated disc-type baffle plate 2 is connected to this via another tie rod and a spacer, and a reaction tube 4 is connected to a through-hole provided in each baffle plate, and the reaction tube connected to this baffle plate is a reactor. Built in the shell 1. Further, the heat medium 10 is introduced into the reactor shell 1 through the annular conduit 11a by an axial flow pump not shown in the drawing. The introduced heating medium 10 moves in the reactor shell 1 while changing the direction by the perforated disk-type baffle 2 and the disk-type baffle 3. In other words, the movement of the heat medium 10 is for removing heat from the reaction tube, and a baffle plate is required to secure the flow path of the heat medium 10, thereby uniformly removing heat from the reaction tube. In this case, all the reaction tubes 4 are always fully supported by the perforated disc type baffle plate 2. When the full support is not provided, that is, for example, the reaction tube 4 that is disposed in the hole portion of the perforated disc baffle plate 2 and is not supported by the baffle plate is connected to the heat medium 10 from the central hole portion of the perforated disc type baffle plate 2. This is because, in such a reaction tube 4, uniform heat removal is insufficient. However, a large amount of lateral movement of the heat medium causes an increase in pressure loss of the heat medium, and excessive motive energy is required.
[0006]
On the other hand, the heat medium introduced into the reactor shell is discharged out of the reactor shell after heat removal from the reaction tube, cooled by a heat exchanger or the like, and circulated and used in the reactor shell. For example, JP-A-8-92147 discloses a method in which a heat exchange agent is co-flowed in a method of catalytic vapor phase oxidation of propene to acrolein while maintaining a specific selectivity and conversion rate using a multi-tubular reactor. And a baffle plate is disposed in the reaction vessel, and a catalytic vapor phase oxidation method is disclosed in which the flow rate of the heat exchange agent is adjusted so that the temperature rise of the heat medium in the reactor is 2 to 10 ° C. According to the method described in this publication, acrolein is obtained by catalytic vapor phase oxidation of propene using a catalytically active composite metal oxide at a temperature warmed in a multi-tubular reactor while reducing the hot spot temperature. Is disclosed.
[0007]
However, the heat yield is calculated by the balance between the amount of heat generated by the reaction and the amount of heat consumed by cooling. In addition, the hot spot temperature is rate-controlled at the place where the highest amount of heat is obtained among the many reaction tubes. Therefore, even if a heat medium is introduced to the reactor shell side in order to remove the reaction heat, if the reaction heat is not uniformly removed throughout the reaction tube, an excessive temperature rise of the reaction tube occurs, and a side reaction occurs. This increases the yield, accelerates the deterioration of the catalyst, and can not deny the danger of runaway reaction. In this respect, as is clear from the example described in Japanese Patent Application Laid-Open No. 8-92147, under the same heat generation conditions, the heat medium can be flown countercurrently or in parallel flow in the reactor shell. The pump power required to limit the temperature rise of the heat medium to 1 ° C. has exactly the same result. Therefore, an efficient means for uniformly reducing the hot spot temperature of each reaction tube is required.
[0008]
Furthermore, gas may be introduced into the reactor shell as the heat medium is introduced into the reactor shell. Since the heat medium undergoes a large temperature change such as heating accompanying heat removal of the reaction tube and subsequent cooling, gas tends to be contained along with expansion and contraction, and this is accumulated in the reactor shell. Generally, when introducing a heat medium into the reactor shell at the start of use of the reactor, the gas vent is opened to facilitate the introduction of the heat medium. Accumulate on top of reactor. For this reason, there is no heat medium in the gas reservoir, and the heat removal from the reaction tube cannot be sufficiently performed. Moreover, the reaction tube may be corroded by the gas.
[0009]
As described above, in the conventional multi-tubular reactor, the baffle plate is disposed in order to remove the heat from the reaction tube, and the heat medium is circulated and used at a specific flow rate. However, the heat removal from the reaction tube is sufficient. Not a thing. In addition, when producing a target product industrially using such a multi-tubular reactor, it is also a serious problem to harmonize the yield of the target product with the power consumption. In particular, if the amount of the heat medium to be circulated is increased in order to efficiently remove the heat by the multitubular reactor, the motive energy for circulating the heat medium is finally increased, which is disadvantageous. Further, if the reaction tube is thinned to increase the heat transfer area, the number of reaction tubes is increased and the reaction apparatus becomes expensive.
[0010]
Accordingly, there is a need for the development of a reactor capable of achieving uniform reduction of heat, reducing the hot spot temperature, and achieving reduction in kinetic energy while maintaining the selectivity of the target product.
[0011]
[Means for Solving the Problems]
As a result of examining the movement of the heat medium in the reactor in detail, the present inventor can downsize the reactor when the reaction tube is also arranged inside the perforated disk-type baffle plate, In addition, the inventors have found that the yield of the target product is not different from the conventional product and completed the present invention.
[0012]
That is, the said subject is achieved by the following (1)-(10).
[0013]
(1) a cylindrical reactor shell in which a plurality of annular conduits for introducing or deriving a heat medium in the radial direction are arranged on the outer periphery and having a raw material supply port and a product discharge port;
A circulation device connecting the plurality of annular conduits to each other;
A plurality of reaction tubes in which the reactor is held by a plurality of tube plates;
In a multi-tubular reactor having a perforated disc-type baffle plate and a disc-type baffle plate in the longitudinal direction of the reaction tube for changing the direction of the heat medium introduced into the reactor shell,
The reaction tube is held at a center interval of 1.2 to 1.4 times the outer diameter of the reaction tube, has a space portion in which the reaction tubes are not arranged at the center of the reactor shell, and has a perforated disk type baffle A reactor for catalytic gas phase oxidation reaction, comprising a reaction tube not supported by a plate.
[0014]
(2) The reactor according to (1), further comprising a reaction tube that is not supported by the disk-type baffle.
[0015]
(3) The cross-sectional area of the space portion is 0.5 to 5% of the cross-sectional area of the reactor shell, the cross-sectional area of the disc-shaped baffle plate is 50 to 95% of the cross-sectional area of the reactor, and The reactor according to (1) or (2) above, wherein the hole cross-sectional area of the disc-shaped baffle is 2 to 25% of the reactor cross-sectional area.
[0016]
(4) Furthermore, the reactor shell Placed in At the circulation conduit of the annular conduit or circulation device , After cooling To circulate the heating medium to the reactor The reactor according to any one of (1) to (3) above, which has a heat medium inlet.
[0017]
(5) Further, a gas discharge conduit for discharging the gas introduced into the reactor shell together with the heat medium and collecting out of the reactor shell is disposed, (1) to (4) above A reactor according to any one of the above.
[0018]
(6) Further, the annular conduit has a plurality of opening rows through which the heat medium passes, the opening width being 5 to 50% of the center interval, and the opening length / opening width value being 0.2 to 20. The reactor according to any one of (1) to (5) above, which is in a range.
[0019]
(7) The reactor according to (6) above, wherein at least one of the opening rows has two or more openings.
[0020]
(8) One or more shielding plates which partition the inside of the reactor shell into two or more closed spaces with respect to the length direction of the reaction tube are provided. The reactor described.
[0021]
(9) The reactor according to any one of (1) to (8), which is for producing (meth) acrylic acid or (meth) acrolein.
[0022]
(10) A process for producing (meth) acrylic acid and / or (meth) acrolein using the reactor according to any one of (1) to (9) above.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to a cylindrical reactor shell having a plurality of annular conduits for introducing or discharging a heat medium in a radial direction arranged on the outer periphery and having a raw material supply port and a product discharge port, and the plurality of annular conduits connected to each other A circulating device, a plurality of reaction tubes holding the reactor by a plurality of tube plates, a perforated disc-type baffle plate and a circle for changing the direction of the heat medium introduced into the reactor shell In a multi-tube reactor having a plate-type baffle plate in the longitudinal direction of the reaction tube, the reaction tube is held at a center interval of 1.2 to 1.4 times the outer diameter of the reaction tube, It is a reactor for catalytic gas phase oxidation reaction which has a space part which does not arrange a reaction tube in the center of a shell, and has a reaction tube which a perforated disk type baffle plate does not support.
[0024]
Conventionally, the baffle plate secures the flow path of the heat medium. Unless all reaction tubes are fully supported by the baffle plate, for example, they exist in the holes of the perforated baffle plate and are not supported by the baffle plate. Since the reaction tubes do not come into contact with the heat medium flow flowing in the surface direction of the baffle plate, and only the up-down flow generated from the outer periphery of the hole portion does not perform sufficient heat exchange, the thermal efficiency is lowered. The disk part of the perforated disk type baffle was fully supported. However, when the reaction tube was also arranged inside the perforated disc type baffle plate, it was unexpected, but when the reaction tube was held at the center interval of the specific range of the outer diameter of the reaction tube, the target product The yield and the selectivity of the target product can be maintained, and the kinetic energy for flowing the heating medium can be reduced, and the cross-sectional area of the reactor with respect to the storage reaction tube can be reduced by this effect. . Hereinafter, embodiments of the present invention will be described with reference to FIG.
[0025]
The present invention includes a cylindrical reactor shell 1 in which a plurality of annular conduits 11a and 11b for introducing or deriving a heat medium in a radial direction are arranged on the outer periphery and having a raw material supply port 50 and a product discharge port 51, and the reaction A plurality of reaction tubes 4 held by two tube plates 6a and 6b separating the raw material supply port 50 and the product discharge port 51 of the reactor shell 1, and the direction of the heat medium introduced into the reactor shell 1 Is a multi-tubular reactor having a perforated disc-type baffle plate 2 and a disc-type baffle plate 3 in the longitudinal direction of the reaction tube.
[0026]
The perforated disc type baffle plate 2 and the disc type baffle plate 3 are alternately arranged in the longitudinal direction of the reaction tube 4, but the perforated disc type baffle plate 2 and the disc type baffle plate 3 The interval is not particularly limited. Accordingly, when the hot spot of the reaction tube varies depending on the catalytic gas phase oxidation reaction to be reacted, the hot spot can be appropriately selected according to the position of the hot spot, the temperature change of the hot spot, and the like.
[0027]
On the other hand, the reaction tube 4 needs to be arranged at a center interval of 1.2 to 1.4 times the outer diameter of the reaction tube, more preferably 1.25 to 1.35 times, particularly preferably. 1.25 to 1.30 times. If it is less than 1.2 times the outer diameter of the reaction tube, the interval between the reaction tubes becomes narrow, which is useful for downsizing the reactor, but the heat removal efficiency in the reaction tube near the center decreases, so the hot spot temperature is reduced. It is difficult to do. On the other hand, if it exceeds 1.4 times, the reactor becomes larger, the linear velocity in the shell decreases, the heat medium drifts, and the heat removal efficiency decreases. However, the inner and outer diameters of the built-in reaction tube itself and the reaction tube length are not particularly limited. Therefore, the size of the reaction tube used for the known catalytic oxidation reaction can be selected. In the present invention, the reaction tube preferably has an inner diameter of 15 to 50 mm, more preferably 20 to 40 mm, and particularly preferably 20 to 30 mm from the viewpoint of heat removal efficiency.
[0028]
In addition, the present invention is characterized by having a reaction tube 4a that is not supported by the perforated disk-type baffle plate 2 while having a space portion at the center of the reactor shell. Conventionally, the reactor shell may have a tie rod and a spacer at the center and all the reaction tubes 4 are supported by the perforated disc-type baffle 2 as described above. By arranging at least one or more rows of reaction tubes 4a shown in FIG. 2 inside the baffle plate 2, the number of reaction tubes accommodated in the same reactor shell diameter can be increased, and at the same time, the kinetic energy of the heat medium can be reduced. In addition, the heat removal efficiency that is different from the conventional one can be ensured. Although the details of this reason are unknown, the pressure loss of the heat medium is reduced by the central space and the arrangement of the reaction tube not supported by the perforated disk-type baffle 2, which leads to a reduction in power energy. In addition, since the linear velocity has been improved, the heat exchange rate has been improved, and it is considered possible to reduce the hot spot temperature and ensure the selectivity, which is different from the conventional one.
[0029]
The space cross-sectional area is preferably 0.5 to 5% with respect to the reactor shell cross-sectional area, more preferably 1 to 4%, and particularly preferably 1 to 2%. If it is less than 0.5%, the flow of the heat medium around the center is poor, the heat removal of the reaction tube becomes insufficient, and the hot spot temperature cannot be reduced. On the other hand, if it exceeds 5%, the reactor shell diameter increases, and the thermal efficiency decreases due to a decrease in linear velocity. In place of the tie rod at the center of the reactor shell 1 or the like, a tie rod and spacer for fixing the perforated disc type baffle plate 2 or the disc type baffle plate 3 are replaced with a perforated disc type baffle plate 2. A plurality of others can be provided so as to penetrate.
[0030]
Further, the cross-sectional area of the disc-shaped baffle plate 3 is preferably 50 to 95%, more preferably 60 to 90%, particularly preferably 70 to 85% of the cross-sectional area in the reactor shell 1. is there. If it is less than 50%, the flow of the heat medium near the reactor shell wall surface is poor and the thermal efficiency is lowered, and if it exceeds 95%, the power energy increases and the flow of the heat medium near the disk-type baffle plate is deteriorated and the heat efficiency is lowered. Because it does.
[0031]
Further, the hole cross-sectional area of the perforated disc type baffle 2 is preferably 2 to 25%, more preferably 4 to 20%, particularly preferably 6 of the cross-sectional area in the reactor shell. ~ 18%. This is because the pressure loss of the heat medium is increased when the content is less than 2%, and uniform heat removal becomes difficult when the content exceeds 25%.
[0032]
The present invention has a reaction tube 4a that is not supported by the perforated disk-type baffle plate 2, but simultaneously has a reaction tube 4b that is not supported by the disk-type baffle plate as shown in FIG. Also good. By disposing such a reaction tube 4b, the number of reaction tubes disposed in the reactor shell 1 can be increased. Moreover, in combination with the selection of the space portion of the central portion, the hole area of the perforated disc-type baffle plate, and the disc-type baffle plate area at a specific ratio, the hot spot temperature can be reduced and the target product can be collected. The rate can be secured.
[0033]
These baffle plates are preferably arranged so as not to overlap the hot spot position, more preferably 100 mm or more, particularly preferably 200 mm or more. This is because if the hot spot position of the reaction tube overlaps with the baffle plate support, the efficiency of heat removal by the heat medium is lowered, and it is difficult to reduce the hot spot temperature. Such a hot spot position can be known by supplying a raw material gas or the like to a reaction tube filled with a catalyst in advance and measuring the temperature of each part of the reaction tube. In addition, what is necessary is just to arrange | position a baffle plate in consideration of the change area, when a hot spot position changes with progress of reaction.
[0034]
In the reactor of the present invention, all or part of the heat medium 10 is discharged out of the reactor shell 1 from the heat medium outlet provided in the annular conduit 11a or 11b, and between the annular conduits 11a and 11b. It is circulated into the reactor shell 1 from the other annular conduit 11b or 11a via the circulation device provided. In the case of having such a circulation device, the heat medium 10 whose flow path is secured by the perforated disc-type baffle plate 2 and the disc-type baffle plate 3 is introduced in an upward flow from the bottom of the reactor toward the top. The flow of the heat medium 10 of the reaction apparatus in this case will be described with reference to FIG.
[0035]
First, among the heat medium 10 introduced from the annular conduit 11a and discharged from the annular conduit 11b, the heat medium (not immediately taken out of the reactor shell 1 and the circulation device 30 and directed toward the heat medium outlet 34 of the circulation device 30 ( The heat medium 10a) is introduced into the circulation device 30 from the heat medium circulation port 31 provided in the annular conduit 11b, and is introduced into the annular conduit 11a through the heat medium discharge port 34, and enters the reactor shell 1 Circulated.
[0036]
On the other hand, a part of the heat medium 10 is taken out of the reactor shell 1 from a heat medium outlet 12 provided in the annular conduit 11b, cooled by a heat exchanger (not shown), and a heat medium circulation port 31 of the circulation device 30. It is introduced from a heat medium introduction port 32 provided opposite to. The discharge of the heat medium 10 to the outside of the reactor shell does not stop through the annular conduit 11b. For example, as shown in FIG. 4, after the heat medium 10 enters the circulation device 30 through the heat medium circulation port 31 from the annular conduit 11b. Then, after being taken out of the reactor shell 1 from the heat medium outlet 12 provided in the upper part of the circulation device 30 and cooled by a heat exchanger (not shown), it is introduced from the heat medium inlet 32 provided in the annular conduit 11b. You may let them. In this way, when the heat medium 10b after cooling is circulated in the vicinity of the annular conduit 11b or the heat medium circulation port 31 of the circulation device 30 after being taken out of the reactor shell and cooled, the heat medium 10a and the heat medium in the circulation device 30 are circulated. Since the supply part with 10b adjoins, both become easy to mix. Further, the heat medium taken out from the heat medium outlet 12 shown in FIG. 4 can be circulated in the reactor shell through, for example, the annular conduit 11b. In this case, it is necessary to take sufficient residence time for mixing in the annular conduit 11b, and the heating medium introduction port 32 ′ is provided at a position facing the heating medium circulation port 31 also in the portion of the annular conduit 11b. Is preferred. FIG. 4 shows the heat medium introduction port 32 when introducing the cooled heat medium 10b into the annular conduit 11b as 32 '. In this case, the heat medium inlet 32 shown in FIG. 4 does not exist. As described above, the reactor of the present invention has the heat medium inlet 32 for introducing the cooled heat medium 10b into the reactor shell 1 or the circulation device 30, and the heat medium circulation port of the annular conduit 11b or the circulation device 30. 31 is preferable. When the heat medium 10b after cooling is circulated in the vicinity of the heat medium outlet 34 of the circulation device 30, the mixing of the heat medium 10a and 10b becomes insufficient, and the temperature of the heat medium 10 circulated in the reactor shell 1 The distribution was uneven and local abnormally high temperatures in the reaction tube 4 were likely to occur. According to the present invention, as described above, in the circulation device 30, the cooled heat medium (heat medium 10b) is supplied to the heat medium circulation port 31, or the heat medium introduction port 32 is provided in a part of the annular conduit 11b. By providing, the heat medium 10a and the heat medium 10b are mixed very efficiently. In addition, the amount of heat absorbed while moving in the circulation device 30 is extremely small, and the reaction heat can be sufficiently removed as a heat medium. In addition, by using the heating medium 10 having a uniform temperature distribution, an abnormally high temperature of the hot spot can be prevented uniformly, and the amount of circulating heating medium can also be reduced.
[0037]
In addition, when providing the heat medium introduction port 32 which introduces the heat medium 10b after cooling in this invention in the circulation apparatus 30, the position facing the heat medium circulation port 31 can be illustrated as shown in FIG. As shown in the embodiment of FIG. 4 to be described later, when the heat medium outlet 12 is provided at the upper part of the circulation device 30, when the heat medium 10 b is introduced from a position opposed to the heat medium circulation port 31, A part of the medium 10b goes out of the reactor from the heat medium outlet 12, which is disadvantageous in terms of thermal efficiency. In such a case, the heat medium outlet that is the closest to the heat medium circulation port 31 in the circulation device 30 and that is the outlet of the heat medium for discharging the heat medium from the circulation device to the reactor shell. 34 is the farthest position. Further, in the case where a plurality of heat medium circulation ports 31 are provided in the circulation device, the heat medium 10b may be introduced in any vicinity thereof. In any case, the mixing of the heat medium 10b and the heat medium 10a is performed efficiently.
[0038]
In the present invention, the heat medium introduction port 32 may be provided in a part of the reactor outlet-side annular conduit connected to the heat medium circulation port of the circulation device. This is because the heat medium 10a and 10b are already mixed when introduced into the circulation device 30 and the heat medium 10 having a uniform heat distribution in the circulation device 30 can be easily prepared. In such a case, it is preferable that the position of the heat medium introduction port 32 is a position facing the circulation device 30 so that the residence time after mixing in the annular conduit can be sufficiently taken.
[0039]
When the heat medium is circulated by upflow as shown in FIG. 4, it can be taken out from the heat medium outlet 12 provided at the upper part of the circulation device 30 using the pump 33. In this case, it is preferable to provide the partition plate 37 so as not to mix with the heat medium 10b introduced from the heat medium introduction port 32 provided in the lower part.
[0040]
The reactor of the present invention may have or be provided with a stirring blade instead of the pump 33 in order to efficiently mix the heat medium 10a and the heat medium 10b in the circulation device 30. . This is because a heat medium having a uniform heat distribution can be obtained more efficiently. The heat medium 10 (heat medium 10a + heat medium 10b) having a uniform heat distribution in this way is again introduced into the reactor shell 1 from the annular conduit 11a via the heat medium outlet 34 of the circulation device 30. In the figure, the flow of the heat medium 10 (10a + 10b), the heat medium 10a, and the heat medium 10b is shown with symbols attached to the arrows indicating the flow paths.
[0041]
In the present invention, the heat medium 10b taken out of the reactor shell 1 is preferably gas-liquid separated either before or after the heat exchange. When the heating medium 10b containing bubbles is used, gas pooling is likely to occur in the upper tube plate portion within the reactor shell, and uniform mixing of the heating medium 10a and the heating medium 10b uses the degassing heating medium. This is because the heat distribution can be made uniform easily. As such a gas-liquid separation method, a method of preventing gas entrainment by reducing the speed or securing the liquid height is representative, and other methods may be used.
[0042]
The reactor of the present invention has annular conduits 11a and 11b. By supplying or discharging the heat medium uniformly from the whole circumference direction of the reactor via the annular conduits 11a and 11b having the openings intermittently communicating with the entire circumference, the heat medium is uniformly supplied and discharged. This is because the temperature can be efficiently reduced. At this time, the annular conduit preferably has a plurality of opening rows through which the heat medium passes. Referring to FIG. 5, for example, the annular conduit 11a has a plurality of opening rows A1, A2, etc., and the center interval A, which is the center distance between the openings of the nearest opening rows in each opening row, is as follows. Each row may be the same or different and is 50 to 500 mm, more preferably 100 to 400 mm, and particularly preferably 200 to 300 mm. This is because if the center distance A is less than 50 mm, the manufacture becomes difficult, and if it exceeds 500 mm, it is difficult to uniformly feed the heat medium outside the reaction tube. Further, the numerical aperture in each aperture row is at least 1 or more. In FIG. 5, the column A1 indicates one numerical aperture, the column A2 indicates two, and the column An indicates four. As described above, since the number of apertures existing in each aperture row is different, the interval between adjacent apertures does not have to coincide with the center interval A as shown in FIG. The opening width B is 5 to 50%, more preferably 10 to 40%, and particularly preferably 20 to 30% of the average center distance, which is an average value of the center distance A. This is because if the opening width is less than 5%, the annular conduit height becomes high and large, while if it exceeds 50%, the opening height is low and it becomes difficult to feed the heat medium over a wide area of the pipe. Furthermore, the value of opening length C / opening width B is preferably in the range of 0.2-20. Note that the center interval A does not have to be the same in all the annular conduits, and similarly, the opening width B does not have to be the same in all the annular conduits. This is because providing a plurality of openings makes it possible to discharge and input the heating medium 10 more uniformly. For this reason, when calculating the opening width B in the present invention, it is calculated using the average center interval. The shape of the opening is not particularly limited, and examples thereof include a circle, an ellipse, an ellipse, and a rectangle.
[0043]
In addition, although the aspect shown to the said FIG.3 and FIG.4 showed the aspect which performs the heating medium 10 by an upflow irrespective of whether a raw material supply is performed by an upflow or a downflow, the reactor of this invention is In carrying out the catalytic gas phase oxidation reaction, the raw material gas introduced into the reaction tube 4 can be used without any limitation, whether upflow or downflow. Further, the heat medium 10 can be introduced with no particular limitation in parallel flow or counter flow with respect to the raw material supply.
[0044]
In addition, the reactor of the present invention is preferably piped with a gas outlet for exhausting the gas accumulated in the upper part of the reactor shell 1 being in close contact with the tube plate in the reactor shell. In general, gas is brought into the reactor shell 1 when the heat medium 10 is introduced, and a space in which no heat medium exists is likely to be formed in the upper part of the reactor shell 1, but there is no heat medium in such a gas reservoir. Sufficient heat removal cannot be performed locally, and abnormal temperature rise tends to occur. Therefore, by providing the gas discharge port, this gas can be removed and filled with a heat medium to prevent local abnormal temperature rise in the reaction tube, and the reaction conditions can be stabilized.
[0045]
Next, the case of introducing the heat medium in the down flow in the reactor of the present invention will be described with reference to FIG. In FIG. 6 as well, a reaction tube 4a that is not supported by the perforated disk-type baffle plate 2 is disposed at the center of the reactor shell. In addition, the cooled heat medium 10 b is introduced into the circulation device 30 from the heat medium introduction port 32. In this case, after the heat medium discharged from the heat medium outlet 12 provided in the annular conduit 11a is pushed up to the heat medium discharge pot 13 disposed above the upper tube plate 6b of the reactor shell 1, for example. It is discharged out of the system from the nozzle 14. In this case, the same amount of the cooling medium as the heating medium 10 b discharged from the system by the heating medium discharge pot 13 is supplied from the heating medium inlet 32. Thereby, the full liquid state of the heating medium 10 in the reactor shell 1 can be ensured. The heat medium 10b taken out from the reactor shell and circulated after cooling, and the heat medium 10a introduced into the circulation device 30 from the heat medium circulation port 31 (removed immediately without being taken out from the reactor shell) The heating medium) is mixed by a pump 33 such as an axial flow pump or a vortex pump, pumped upward, and introduced into the reactor shell 1 from the heating medium discharge port 34 through the annular conduit 11b. The introduction amount of the heat medium may be adjusted within the range of the circulation heat medium amount.
[0046]
In any of the embodiments of the reactor of the present invention, the supply of the heat medium to the reaction shell 1 side and the discharge from the shell side are annular conduits 11a disposed on the upper and lower outer peripheral portions of the reactor, respectively. , 11b. In this case, the heat medium 10 may be discharged and input at a plurality of locations of the annular conduits 11a and 11b. For this purpose, two or more circulation devices may be provided. Even if the number of pumps is simply increased, it is difficult to adjust a heat medium having a uniform temperature distribution. However, according to the present invention, since a heat medium having a uniform temperature distribution is supplied in the circulation device, a plurality of heat mediums are supplied. This is because more efficient heat removal can be achieved by arranging the circulation device.
[0047]
Furthermore, the reactor of the present invention is provided with back pressure means before and after the heat medium outlet of the heat medium 10b so that a sufficient back pressure is applied to the heat medium 10 flowing down the reaction tube. A state can be secured. When extracting the heat medium 10b to the outside of the reactor shell 1, it is preferable that a full liquid state by the heat medium 10 inside the reactor shell 1 can be secured. However, by providing a means with back pressure, the reaction tube flows down. This is because a sufficient back pressure can be applied to the heat medium to ensure a full liquid state. Examples of such back pressure applying means include a resistance orifice, a valve, and a heat exchanger. Therefore, such back pressure applying means can be further arranged in the reactor of the present invention.
[0048]
Also in the embodiment of FIG. 6, when the gas introduced along with the supply of the heat medium to the upper part of the reactor shell 1 is accumulated inside the reactor shell side, the reactor outer periphery is formed from the upper part of the reactor shell 1. Alternatively, the heat medium discharge pot 13 and the heat medium circulation device 30 may be extracted to the upper space through the pipe 15 and the pipe 16 inserted to the center. This is because such a gas extraction conduit can prevent the generation of gas pools in the reactor shell 1 which causes non-uniform heat removal in the reactor and causes abnormal reactions. For example, as shown in FIG. 6, a gas discharge conduit 16 disposed at the upper portion of the reactor shell 1 is communicated with a gas phase portion of a heat medium discharge pot 13 positioned at the upper portion of the reactor upper tube plate surface. The gas can be discharged from the outlet 17 or the gas discharge conduit 15 in the reactor shell 1 can be discharged to the upper space of the circulation device 30 having the gas discharge nozzle 36.
[0049]
FIG. 7 shows an example of the arrangement of the gas discharge conduit. For the gas accumulated on the outer periphery of the reactor, for example, a flow path is formed in the upper tube sheet 6b like the gas discharge conduit 15 to form the reactor. The gas may be connected to the outside of the shell 1, and with respect to the gas accumulated in the center of the reactor shell 1, a gas discharge conduit 16 may be disposed immediately below the upper tube sheet 6 b.
[0050]
Hereinafter, a method for producing (meth) acrylic acid or (meth) acrolein by a catalytic gas phase oxidation reaction of propylene or isobutylene-containing gas in the reactor of the present invention will be described with reference to FIG.
[0051]
The catalytic gas phase oxidation reaction of the present invention is performed by supplying a raw material gas to the catalyst 5 filled in the reaction tube 4, and the raw material gas mixed with the reaction raw material and air is supplied from the raw material gas supply port 50 to the reactor shell. 1 is supplied into the reaction tube 4 filled with the catalyst 5 in 1, is oxidized in the reaction tube to become a reaction product, and is then discharged from the product gas outlet 51.
[0052]
In order to produce acrylic acid by carrying out a two-stage contact gas phase oxidation reaction of propylene-containing gas in the present invention, for example, as a pre-stage catalyst, it is generally used to produce acrolein by gas phase oxidation reaction of a propylene-containing raw material gas. The oxidation catalyst used can be used. Similarly, the latter catalyst is not particularly limited, and is an oxidation generally used for producing acrylic acid by gas phase oxidation of a reaction gas mainly containing acrolein obtained by the former stage by a two-stage catalytic gas phase oxidation method. A catalyst can be used.
[0053]
As the pre-stage catalyst, the general formula Mo _a -Bi _b -Fe _c -A _d -B _e -C _f -D _g -O _x (Mo, Bi and Fe represent molybdenum, bismuth and iron, respectively, A represents at least one element selected from nickel and cobalt, B represents at least one element selected from alkali metal and thallium, C Represents at least one element selected from the group consisting of phosphorus, niobium, manganese, cerium, tellurium, tungsten, antimony and lead, and D represents at least one element selected from the group consisting of silicon, aluminum, zirconium and titanium O represents oxygen, a, b, c, d, e, f, g and x represent the atomic ratio of Mo, Bi, Fe, A, B, C, D and O, respectively, a = 12, b = 0.1-10, c = 0.1-10, d = 2-20, e = 0.001-5, f = 0-5, g = 0-30, x The materials can be exemplified that represented by a) a value determined by the oxidation state of each element.
[0054]
Further, as the latter stage catalyst, the general formula Mo _a -V _b -W _c -Cu _d -A _e -B _f -C _g -O _x (Mo represents molybdenum, V represents vanadium, W represents tungsten, Cu represents copper, A represents at least one element selected from antimony, bismuth, tin, niobium, cobalt, iron, nickel and chromium, B represents an alkali metal, Represents at least one element selected from alkaline earth metals and thallium, C represents at least one element selected from silicon, aluminum, zirconium and cerium, O represents oxygen, a, b, c, d, e, f, g, and x represent the atomic ratios of Mo, V, W, Cu, A, B, C, and O, respectively, and when a = 12, b = 2-14, c = 0 12, d = 0.1-5, e = 0-5, f = 0-5, g = 0-20, and x is a value determined by the oxidation state of each element). .
[0055]
As a catalyst used in the present invention for obtaining methacrylic acid by isobutylene, t-butanol, methyl-t-butyl ether by a two-stage catalytic gas phase oxidation reaction, for example, a raw material gas containing isobutylene or the like as a first stage catalyst is gas phase oxidized An oxidation catalyst generally used for reacting to produce methacrolein can be used. Similarly, the latter catalyst is not particularly limited, and is generally used to produce methacrylic acid by gas phase oxidation of a reaction gas mainly containing methacrolein obtained by the former stage by a two-stage catalytic gas phase oxidation method. An oxidation catalyst can be used.
[0056]
Specifically, as the pre-stage catalyst, the general formula Mo _a -W _b -Bi _c -Fe _d -A _e -B _f -C _g -D _h -O _x (Mo, W, and Bi represent molybdenum, tungsten, and bismuth, Fe represents iron, A represents nickel and / or cobalt, and B represents alkali metal, alkaline earth metal, and thallium, respectively. C represents at least one element selected from the group consisting of phosphorus, tellurium, antimony, tin, cerium, lead, niobium, manganese and zinc, and D represents silicon and aluminum. Represents at least one element selected from the group consisting of titanium and zirconium, O represents oxygen, and a, b, c, d, e, f, g, h and x represent Mo, W, respectively. , Bi, Fe, A, B, C, D and O, where a = 12, b = 0-10, c = 0.10, d = 0. ~20, e = 2~20, f = 0.001~10, g = 0~4, h = 0~30, and x is a numerical value determined by the oxidation state of each element.)
The latter catalyst is not particularly limited as long as it is one or more oxide catalysts containing molybdenum and phosphorus as main components. For example, a phosphomolybdic acid heteropolyacid or a metal salt thereof is preferable. General formula Mo _a -P _b -A _c -B _d -C _e -D _f -O _x The thing represented by these is preferable. (Wherein Mo represents molybdenum, P represents phosphorus, A represents at least one element selected from the group consisting of arsenic, antimony, germanium, bismuth, zirconium and selenium, B represents copper, Represents at least one element selected from the group consisting of iron, chromium, nickel, manganese, cobalt, tin, silver, zinc, palladium, rhodium and tellurium, and C represents a group consisting of vanadium, tungsten and niobium. D represents at least one element selected from the group consisting of alkali metals, alkaline earth metals and thallium, O represents oxygen, a, b, c, d, e, f and x represent the atomic ratios of Mo, P, A, B, C, D and O, respectively, and when a = 12 is fixed, b = 0.5-4 c = 0~5, d = 0~3, e = 0~4, f = 0.01~4 and x is a numerical value determined by the oxidation state of each element.)
The shape of the catalyst is not particularly limited, and it can be spherical, columnar, cylindrical, etc., and the molding method can be support molding, extrusion molding, tableting molding, etc. A form in which a catalyst material is supported is also useful.
[0057]
The conditions for the gas phase catalytic oxidation reaction of propylene and isobutylene with molecular oxygen can be performed by a conventionally known method. For example, taking propylene as an example, the concentration of propylene in the raw material gas is 3 to 15% by volume, the ratio of molecular oxygen to propylene is 1 to 3, and the rest is nitrogen, water vapor, carbon oxide, propane, and the like.
[0058]
Air is advantageously used as the supply source of molecular oxygen, but oxygen-enriched air or pure oxygen can be used if necessary, and a one-pass method or a recycling method is used. The reaction temperature is 250 ° C. to 450 ° C., the reaction pressure is from normal pressure to 500 kPa, and the space velocity is 500 to 3000 h. ^-1 It is preferable to carry out within the range of (STP).
[0059]
In the case of the gas phase catalytic oxidation reaction of isobutylene, the concentration of isobutylene in the raw material gas is 1 to 10% by volume, the concentration of molecular oxygen with respect to isobutylene is 3 to 20% by volume, and water vapor is 0 to 60% by volume. The rest is nitrogen, water vapor, carbon oxide and the like. Air is advantageously used as the molecular oxygen supply source, but oxygen-enriched air or pure oxygen can be used if necessary. The reaction temperature is 250 to 450 ° C., the reaction pressure is normal to 500 kPa atmospheric pressure, and the space velocity is 300 to 5000 h. ^-1 It is preferable to carry out within the range of (STP).
[0060]
Next, in the heat exchange type multi-tubular second reactor in which each tube of the tube bundle portion in the shell was filled with the above-described oxide catalyst (second-stage catalyst) to produce acrylic acid, the obtained reaction was obtained in the preceding stage reaction. A mixed gas obtained by adding secondary air, secondary oxygen or water vapor to the acrolein-containing gas as necessary is used at a reaction temperature (reactor heat medium temperature) of 100 to 380 ° C., preferably 150 to 350 ° C. and a space velocity of 300. ~ 5,000hr ^-1 (STP) is supplied and the subsequent reaction is performed to obtain acrylic acid.
[0061]
Further, in the heat exchange type multi-tubular second reactor in which each tube of the tube bundle portion in the shell is filled with an oxide catalyst containing molybdenum and phosphorus (second-stage catalyst) for generating methacrylic acid, A mixed gas obtained by adding secondary air, secondary oxygen or water vapor to the methacrolein-containing gas obtained by the reaction, if necessary, is reacted at a reaction temperature (reactor heat medium temperature) of 100 to 380 ° C., preferably 150 to 350 ° C. and space velocity 300 to 5,000 hr ^-1 (STP) is supplied, and the latter reaction is performed to obtain methacrylic acid.
[0062]
The present invention can also be applied to a reactor in which upper and lower chambers are formed by an intermediate tube plate.
[0063]
Next, application to a reactor of a type in which upper and lower chambers are formed by an intermediate tube plate will be described with reference to FIG. FIG. 8 is an explanatory view showing an example of a longitudinal section of the reactor of the present invention, and the reactor has two chambers A and B. FIG. A large number of reaction tubes 4 are loaded inside a reactor shell 1 having a circular cross-sectional shape, and each reaction tube is expanded at its lower end to the lower tube sheet 6a and at its upper end to the upper tube sheet 6b. Alternatively, it is fixed by a known method such as welding. Further, it is preferable that a passage from the bottom to the top of the heat medium is provided in the central portion of the reactor shell 1 without providing the reaction tube 4 so that the heat medium is efficiently moved also in the central portion. Further, the shell side of the reactor shell 1 is partitioned up and down by an intermediate tube plate 8 located at a substantially intermediate position between the upper end and the lower end of the reaction tube 4 to constitute two chambers A and B.
[0064]
In the chambers A and B of FIG. 8, in order to reduce the temperature distribution in the lateral direction by dispersing the heat medium in the lateral direction, a plurality of perforated disc-type baffle plates 2 and a plurality of discs as shown in the figure. The mold baffle plates 3 are provided alternately. In the present invention, it goes without saying that there are reaction tubes 4 that are not supported by the perforated disc-type baffle plate 2 or the disc-type baffle plate 3 disposed in each chamber. The reaction tube is held at a center interval 1.2 to 1.4 times the outer diameter of the reaction tube. A reaction tube not supported by the perforated disk-type baffle plate 2 is indicated by 4a, and a reaction tube not supported by the disk-type baffle plate 3 is indicated by 4b.
[0065]
FIG. 9 is an enlarged explanatory view of a cross section of a close contact portion between the reaction tube and the intermediate tube plate. The reaction tube 4 and the intermediate tube plate 8 are preferably made of the same material such as steel in consideration of expansion and contraction due to heating and cooling.
[0066]
The reaction tube 4 may use a catalyst as a fixed bed and may be filled with a catalyst according to the purpose of the reaction. For example, in order to produce acrylic acid by a two-stage catalytic gas phase oxidation reaction of a propylene-containing gas, As a side catalyst, an oxidation catalyst generally used for producing acrolein by gas phase oxidation reaction of a raw material gas containing propylene can be used. Similarly, the downstream catalyst is not particularly limited, and is generally used for producing acrylic acid by vapor phase oxidation of a reaction gas mainly containing acrolein obtained upstream by a two-stage catalytic gas phase oxidation method. The oxidation catalyst can be used.
[0067]
The upstream catalyst for the production of acrylic acid can be used as the upstream catalyst, and the downstream catalyst for the production of acrylic acid can be used as the downstream catalyst.
[0068]
The catalyst constituting the upstream catalyst layer and the downstream catalyst layer does not need to be a single catalyst. For example, a plurality of types of catalysts having different activities are sequentially filled, or a part of the catalyst if necessary. May be diluted with an inert material such as an inert carrier. The same applies to the other catalysts described below.
[0069]
Also, the shape of the catalyst is not particularly limited, and it can be a Raschig ring shape, a spherical shape, a cylindrical shape, a ring shape, etc., and the molding method can be support molding, extrusion molding, tableting molding, etc. A form in which these catalyst substances are supported on a carrier is also useful.
[0070]
Here, a method and a packing form of the catalyst in the reactor in which the upper and lower chambers are formed by the intermediate tube plate will be described.
[0071]
First, before filling the catalyst, a wire mesh or a receiver 14 is installed at the lower end of the reaction tube 4 to prevent the catalyst from dropping. Before the catalyst is filled, if necessary, a refractory 22 that is inert to the reaction is filled, and the upstream catalyst 21 is filled in the reaction tube 4. Next, the downstream catalyst 23 is filled. Between the upstream catalyst 21 and the downstream catalyst 23, a refractory 22 that is inert to the reaction can be filled.
[0072]
In FIG. 8, the filling of the catalyst is omitted for the sake of clarity of the drawing, but FIG. 9 shows an example of the filling of the catalyst with respect to one reaction tube. As shown in FIG. 9, an inert refractory 22 is filled in the lower part of the B chin bar area, then the upstream catalyst 21 is filled, and further, the inert gas from the upper part to the A chamber area through the intermediate tube plate 8. The refractory 22 is filled, and the downstream catalyst 23 is filled in the remaining A chamber region. When the temperature of the B chamber was higher than that of the A chamber, the raw material gas was partially oxidized by the upstream catalyst 21, then cooled at the site of the inert refractory 22, and then cooled at the site of the downstream catalyst 23. The target product is produced by further partial oxidation while maintaining the temperature. Therefore, in the A chamber region, the portion of the inert refractory 22 corresponds to the cooling layer, and the downstream catalyst 23 corresponds to the reaction layer.
[0073]
Examples of the inert refractory include α-alumina, alundum, mullite, carborundum, stainless steel, silicon carbide, steatite, earthenware, porcelain, iron, and various ceramics.
[0074]
The inert refractory is, for example, granular and does not necessarily need to be uniformly filled throughout the inert refractory layer, but for effective cooling of the reaction gas, It is preferable to fill substantially uniformly. The same applies to an inert refractory having a shape other than granular.
[0075]
One of the functions of the inert refractory layer is that when the A chamber temperature is lower than the B chamber temperature, the product-containing gas from the upstream catalyst is quenched to a temperature range suitable for the oxidation reaction in the downstream catalyst layer. Is to adjust the temperature of the reaction gas. For this reason, it is necessary to provide the inert refractory layer so as to have a length that can sufficiently exhibit the above-described function.
[0076]
Therefore, in the present invention, the inert refractory layer in the vicinity of the central tube plate is long enough to cool the reaction gas from the upstream catalyst layer to a temperature suitable for the downstream catalyst layer, and the upstream catalyst layer. It is preferable that the catalyst at the outlet and the catalyst at the inlet of the downstream catalyst layer are both arranged so as not to be substantially affected by heat from the intermediate tube plate. In this respect, in the present invention, since the movement of the heat medium between the chambers is mitigated and the thermal influence can be reduced, the length of the inert refractory layer can also be shortened. Therefore, the length of the reaction tube filled with the catalyst layer, that is, the height of the reactor can be shortened, and a simple apparatus can be obtained.
[0077]
Specifically, the length of the inert refractory layer is defined as the temperature of the reaction gas entering the downstream catalyst layer from the inert refractory layer, that is, the temperature of the reaction gas at the downstream catalyst layer inlet (the heating medium is In the case of flowing in parallel with the raw material or the product gas, the length may be long enough to cool so as to be equal to or lower than the heating medium inlet temperature + 15 ° C.
[0078]
Another function of the inert refractory layer is that the molybdenum component sublimated from the upstream catalyst in the production of impurities contained in the reaction gas, for example acrylic acid, when the reaction gas from the upstream reaction layer passes through. In addition to preventing pressure loss due to adhesion of high-boiling substances such as terephthalic acid as a by-product, it is also possible to prevent these impurities from directly entering the downstream catalyst layer and degrading the catalyst performance. For this function only, the porosity of the inert refractory may be lowered, but if it is too low, the pressure loss increases, which is not preferable. Therefore, in the present invention, the porosity of the inert refractory layer is usually 40 to 99.5%, preferably 45 to 99%. The “porosity” is defined by the following formula:
Porosity (%) = {(X−Y) / X} × 100
here,
X: Volume of inert refractory layer
Y: The actual volume of the inert refractory (the actual volume means, for example, in the case of a ring, the actual volume excluding the central space).
[0079]
If the porosity is less than 40%, the pressure loss increases. On the other hand, if it exceeds 99.5%, the impurity trapping function is lowered and the reaction gas cooling function is also lowered.
[0080]
An inert refractory is preferable because it leads to an improvement in the yield of the product if it is inserted into the inlet of the upstream catalyst for preheating the raw material gas.
[0081]
In addition, the filling of the catalyst in such a reaction tube does not ask | require whether each reaction tube is supported by a disk type baffle plate or a perforated disk type baffle plate. Therefore, even if it is the reaction tube arrange | positioned in any place in the reactor shell 1, what was similarly filled with the catalyst can be used.
[0082]
Next, the flow of the heat medium in the case of producing acrylic acid using a reactor in which upper and lower chambers are formed by an intermediate tube plate will be described with reference to FIG. Known conditions for obtaining acrolein from propylene can be applied to the source gas and inert gas supplied to chamber B, the catalyst to be filled, the reaction temperature, etc. Also, the source gas and inert gas supplied to chamber A can be applied. Known conditions for obtaining acrylic acid from acrolein can be applied to the gas, the catalyst to be filled, the reaction temperature, and the like. For this reason, the flow of the heat medium introduced into each chamber, which is a particularly characteristic feature, will be described here. In FIG. 8, the raw material gas is supplied from the lower part of the reactor and is brought into contact with the catalyst to obtain a product. Show the case.
[0083]
First, in the chamber B in which the first stage reaction is performed, the heat is discharged from the heat medium outlet 34 of the pump 35 to the chamber B through the lower tubular conduit 11 a provided on the outer periphery of the reactor shell 1. The heat medium enters the shell 1 from almost the entire circumference of the inner periphery of the reactor by the tubular conduit 11a, and then contacts the reaction tube 4 to absorb the reaction heat generated by the catalytic reaction, and has a perforated disk shape. The flow path is changed by the baffle plate 2 and the disk-type baffle plate 3, and the head is directed to the upper part of the reactor. At this time, the heat medium rises at the perforated portion of the perforated disk-type baffle plate 2, but the reaction tube is held at a center interval of 1.2 to 1.4 times the outer diameter of the reaction tube. In the reaction tube 4a that is not supported by the perforated disk-type baffle, sufficient heat exchange is performed. Next, the heat medium absorbs the reaction heat while being in contact with the reaction tube 4 substantially horizontally along the disc-shaped baffle plate 3 and proceeds toward almost the entire area of the inner periphery of the reactor, as described above. As a result of the reaction tube being held at a center interval 1.2 to 1.4 times the outer diameter of the reaction tube, sufficient heat exchange is performed even in the reaction tube 4b not supported by the disc-shaped baffle plate 3. Ascending from the outer periphery of the disc-shaped baffle plate 3. The heat medium reaching the upper part of the reactor shell 1 is discharged from the heat medium circulation port 31 of the upper tubular conduit 11 a in the chamber B, and then cooled by the heat exchanger 24. The cooled heat medium enters the reactor shell 1 from the heat medium outlet 34 of the pump through the lower tubular conduit 11a by using a known pump 35 such as a spiral pump or an axial flow pump, and repeats the above circulation. Although there may be a gap between the perforated disk-type baffle plate 2 and the reactor shell 1, it is preferable to eliminate the gap for the purpose of reducing the temperature distribution of the heat medium in the reactor. The reaction gas can be supplied from the upper part of the reactor by changing the order of filling the catalyst. In the chamber A as well, the heat medium is circulated similarly to the chamber B. Moreover, the circulation method of a heat medium can also circulate either or both of AB in the reverse direction as needed. However, from the viewpoint of protecting the pump 35, it is preferable that the heat medium passes through the pump 35 after the heat medium becomes relatively low temperature through the heat exchanger 24.
[0084]
According to the present invention, it is also possible to produce maleic anhydride with a known catalyst and reaction system using benzene or butane as a raw material gas, and phthalic anhydride with a known catalyst and reaction system using xylene and / or naphthalene as a raw material gas. .
[0085]
As the heat medium to be circulated in the reactor shell 1, any conventionally known heat medium can be used. For example, a molten ether, a nighter, or a phenyl ether heat medium that is a dowsum organic heat medium can be used.
[0086]
According to the present invention, by disposing the space in the center of the reactor shell and the reaction tube that is not supported by the perforated disk-type baffle plate, the kinetic energy can be reduced, and the selectivity of the target product and Yield can be tampered with. In addition, since the hot spots in the reaction tube can be reduced uniformly, deterioration of the catalyst can be efficiently prevented and the life of the catalyst can be extended.
[0087]
【Example】
Hereinafter, examples of the present invention will be described in detail.
[0088]
(Catalyst Production Example 1)
While heating and stirring 150 liters of pure water, 100 kg of ammonium molybdate, 6.3 kg of ammonium paratungstate, and 27.5 kg of nickel nitrate were dissolved. Separately, 68.7 kg of cobalt nitrate is dissolved in 100 liters of pure water, 19 kg of ferric nitrate is dissolved in 30 liters of pure water, and 22.9 kg of bismuth nitrate is dissolved in 30 liters of pure water to which 6 liters of concentrated nitric acid is added. After that, a mixed nitrate aqueous solution was added dropwise. Subsequently, a solution prepared by dissolving 14.2 kg of a 20 mass% silica sol solution and 0.38 kg of potassium nitrate in 15 liters of pure water was added. The suspension thus obtained was heated and stirred to evaporate to dryness, and then dried and ground. The obtained powder was molded into a cylindrical shape with a diameter of 5 mm and calcined at 460 ° C. for 6 hours under air flow to obtain a catalyst. The molar composition of the catalyst was Mo 12, Bi 1.0, Fe 1.0, Co 5, Ni 2.0, W 0.5, Si 1.0, K 0.08.
[0089]
(Catalyst production example 2)
While heating and stirring 500 liters of pure water, 100 kg of ammonium molybdate, 19.1 kg of ammonium paratungstate and 30.4 kg of ammonium metavanadate were added and dissolved. Separately, 20.5 kg of copper nitrate and 3.4 kg of antimony trioxide were added to 50 liters of pure water. Further, 350 kg of a silica-alumina carrier having an average particle diameter of 5 mm was added to this mixed solution, and the catalyst component was supported on the carrier by evaporating to dryness. By repeating this, a predetermined amount of catalyst was obtained. The molar composition of the catalyst was Mo 12, V 5.5, W 1.5, Cu 1.8, Sb 0.5.
[0090]
Example 1
Using the reactor shown in FIG. 3, 5.6 m of a catalyst for mainly producing acrolein from propylene in the reaction tube obtained in Catalyst Production Example 1 above. ^Three The raw material gas of 7vol% of propylene, 12.6vol% of oxygen, 10vol% of water vapor, 70.4vol% such as nitrogen was charged so that the catalyst contact time was 2 seconds. As a heating medium, a heating medium consisting of 50% by mass of potassium nitrate and 50% by mass of sodium nitrite is 2900 m at an inlet temperature of 315 ° C. ^Three / H axial flow pump. In the reactor, there are a reaction tube that is not supported by the perforated disc baffle and a reaction tube that is not supported by the disc baffle.
[0091]
When the product from the reactor product outlet was measured, the propylene reaction rate was 97.0% and the acrolein selectivity was 84.8%. Further, when estimated by simulation, the propylene reaction rate was 97.1% and the acrolein selectivity was 84.7%, which was almost traceable.
[0092]
(Comparative Example 1)
In Example 1, the propylene reaction rate and acrolein selectivity were simulated in the same manner as in Example 1 except that the hole diameter of the perforated disk-type baffle was changed to the diameter shown in Table 1. The results are shown in Table 1. As a result, the axial pump power increased 5.4 times without any change in selectivity and yield. In the reactor, there are no reaction tubes that are not supported by the perforated disk-type baffle, and there are reaction tubes that are not supported by the disk-type baffle.
[0093]
(Comparative Example 2)
As a reactor that does not have a reaction tube that is not supported by the perforated disk-type baffle, the hollow diameter shown in Table 1 and the hole diameter of the perforated disk-type baffle are changed, and the same operation as in Example 1 is performed. I got acrolein. The results are shown in Table 1. In the reactor, there are no reaction tubes that are not supported by the perforated disk-type baffle, and there are reaction tubes that are not supported by the disk-type baffle. As a result, the axial pump power increased 1.8 times without changing the selectivity and yield.
[0094]
(Example 2)
Except that the diameter of the perforated disk-type baffle plate and the central space portion are the same as in Example 1, and the diameter of the disk-type baffle plate and the reactor shell diameter are the values shown in Table 1, the same as in Example 1. I got acrolein. The results are shown in Table 1. In the reactor, there are reaction tubes that are not supported by the perforated disk-type baffle, but there are no reaction tubes that are not supported by the disk-type baffle. As a result, the axial pump power ratio was 0.97.
[0095]
(Comparative Example 3)
Acrolein was obtained by operating under the same conditions as in Example 2 except that the hole diameter of the perforated disk type baffle plate was changed to the value shown in Table 1. The results are shown in Table 1. In the reactor, there is no reaction tube that is not supported by the perforated disk-type baffle and no reaction tube that is not supported by the disk-type baffle.
[0096]
Example 3
Using the reactor shown in FIG. 8, the length of one reaction tube is 7 m, the inner diameter is 25 mm, the outer diameter is 29 mm, 4100 steel reaction tubes, an intermediate tube plate, and a pre-stage catalyst. Except for using the catalyst of Catalyst Production Example 1 as the latter stage catalyst, the reactor body diameter, the central space diameter, the disk-type baffle diameter, the perforated disk-type baffle plate The reactor was operated using a single reactor having the same hole diameter, hollow area / body area, disc area / body area, and perforated area / body area as in Example 1. The results are shown in Table 1.
[0097]
(Comparative Example 4)
The reactor was operated under the same conditions as in Example 3 except that the diameter of the reactor barrel, the diameter of the disk-type baffle and the hole diameter of the perforated disk-type baffle were changed to the values shown in Table 1. The results are shown in Table 1. In the reactor, there is no reaction tube that is not supported by the perforated disk-type baffle and no reaction tube that is not supported by the disk-type baffle.
[0098]
[Table 1]

[0099]
【The invention's effect】
When a reaction tube that does not support the holed disk type baffle area was placed, the axial pump power could be reduced to 1 / 5.4. Moreover, the axial pump power can be reduced without changing the selectivity and the yield of the target product.
[Brief description of the drawings]
FIG. 1 is a schematic explanatory view showing a conventional multitubular reactor.
FIG. 2 is a view showing a perforated disk-type baffle plate, a disk-type baffle plate, a reaction tube, and a space portion of the reactor of the present invention.
FIG. 3 is a diagram showing a circulation path of a heat medium in a reactor having a circulation device.
FIG. 4 is a schematic view of a reactor in which a heat medium is taken out from a part of the circulation device and a cooled heat medium is introduced into the circulation device.
FIG. 5 shows an opening row of annular conduits.
FIG. 6 is a diagram showing the flow of the heat medium in the reactor when the heat medium is flowed in a down flow.
FIG. 7 is a view showing the arrangement of gas discharge ports in the upper tube sheet portion.
FIG. 8 is an explanatory view of an example of a longitudinal section of the two-chamber catalytic gas phase oxidation reactor of the present invention.
FIG. 9 is an enlarged explanatory view of a cross section of a catalyst layer in a reaction tube and an intermediate tube plate in FIG.
[Explanation of symbols]
1 ... Reactor shell
2 ... Perforated disk type baffle
3 ... Disc type baffle
4 ... Reaction tube
4a ... Reaction tube not supported by a perforated disk-type baffle
4b ... Reaction tube not supported by disk-type baffle
5, 21, 23 ... Catalyst
6a ... Lower tube sheet
6b ... Upper tube sheet
7 ... Tie rod
8 ... Central tube sheet
10, 10a, 10b ... heating medium
11a, 11b ... annular conduit
12 ... Heat medium outlet
13 ... Heating medium discharge pot
14 ... Nozzle
15, 16 ... Gas discharge conduit
17 ... Nozzle
18 ... Receiver
22 ... Inert refractory
24 ... Heat exchanger
30 ... circulator
31 ... Heat medium circulation port
32, 32 '... Heat medium inlet
33 ... stirring blade
34 ... Heat medium outlet
35 ... Pump
36 ... Nozzle
37 ... Partition plate
50 ... Raw material supply port
51 ... Product outlet
φ1 ... perforated disk type baffle hole diameter
φ2 ... Disk type baffle diameter
φ3: Reactor shell inner diameter
φ4 ... Space part diameter

Claims (10)

A cylindrical reactor shell having a plurality of annular conduits for introducing or deriving a heat medium in a radial direction arranged on the outer periphery and having a raw material supply port and a product discharge port;
A circulation device connecting the plurality of annular conduits to each other;
A plurality of reaction tubes in which the reactor is held by a plurality of tube plates;
In a multi-tubular reactor having a perforated disc-type baffle plate and a disc-type baffle plate in the longitudinal direction of the reaction tube for changing the direction of the heat medium introduced into the reactor shell,
The reaction tube is held at a center interval of 1.2 to 1.4 times the outer diameter of the reaction tube, has a space portion in which the reaction tubes are not arranged at the center of the reactor shell, and has a perforated disk type baffle A reactor for catalytic gas phase oxidation reaction, comprising a reaction tube not supported by a plate. The reactor according to claim 1, further comprising a reaction tube which is not supported by the disk-type baffle plate. The cross-sectional area of the space is 0.5 to 5% of the cross-sectional area of the reactor shell, the cross-sectional area of the disc-type baffle is 50 to 95% of the cross-sectional area of the reactor, and the perforated disk type The reactor according to claim 1 or 2, wherein the baffle plate has a hole cross-sectional area of 2 to 25% of the cross-sectional area of the reactor. Furthermore, the heating medium circulation port of the reactor shell arranged annular conduit or circulation apparatus, characterized by having a heating medium inlet for circulating the reactor heating medium after cooling, claim 1 The reactor in any one of -3. The reaction according to any one of claims 1 to 4, further comprising a gas discharge conduit for discharging a gas introduced into the reactor shell together with the heat medium and accumulated outside the reactor shell. vessel. Further, the annular conduit has a plurality of opening rows through which the heat medium passes, the opening width is 5 to 50% of the center interval, and the opening length / opening width value is in the range of 0.2 to 20. The reactor according to any one of claims 1 to 5, wherein The reactor according to claim 6, wherein at least one of the openings has two or more openings. The reaction according to any one of claims 1 to 7, further comprising one or more shielding plates for partitioning the inside of the reactor shell into two or more closed spaces with respect to the length direction of the reaction tube. vessel. The reactor according to any one of claims 1 to 8, which is used for producing (meth) acrylic acid or (meth) acrolein. The manufacturing method of (meth) acrylic acid and / or (meth) acrolein using the reactor in any one of Claims 1-9.

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